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A YANG Data Model for IP Management
RFC 8344

Document	Type	RFC - Proposed Standard (March 2018) Obsoletes RFC 7277 Was draft-ietf-netmod-rfc7277bis (netmod WG)
	Author	Martin Björklund
	Last updated	2018-12-19
	RFC stream	Internet Engineering Task Force (IETF)
	Formats	txt html pdf htmlized bibtex
	Additional resources	Mailing list discussion
IESG	Responsible AD	Benoît Claise
	Send notices to	(None)

Email authors Email WG IPR References Referenced by Search Lists

RFC 8344

Internet Engineering Task Force (IETF) M. Bjorklund
Request for Comments: 8344 Tail-f Systems
Obsoletes: 7277 March 2018
Category: Standards Track
ISSN: 2070-1721

A YANG Data Model for IP Management

Abstract

This document defines a YANG data model for management of IP
implementations. The data model includes configuration and system
state.

The YANG data model in this document conforms to the Network
Management Datastore Architecture defined in RFC 8342.

This document obsoletes RFC 7277.

Status of This Memo

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.

Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8344.

This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.

Bjorklund Standards Track [Page 1]
RFC 8344 YANG IP Management March 2018

Table of Contents

1. Introduction ....................................................2
1.1. Summary of Changes from RFC 7277 ...........................2
1.2. Terminology ................................................3
1.3. Tree Diagrams ..............................................3
2. IP Data Model ...................................................4
3. Relationship to the IP-MIB ......................................5
4. IP Management YANG Module .......................................7
5. IANA Considerations ............................................27
6. Security Considerations ........................................27
7. References .....................................................29
7.1. Normative References ......................................29
7.2. Informative References ....................................31
Appendix A. Example: NETCONF <get-config> Reply ...................32
Appendix B. Example: NETCONF <get-data> Reply .....................33
Acknowledgments ...................................................34
Author's Address ..................................................34

1. Introduction

This document defines a YANG data model [RFC7950] for management of
IP implementations.

The data model covers configuration of per-interface IPv4 and IPv6
parameters as well as mappings of IP addresses to link-layer
addresses. It also provides information about which IP addresses are
operationally used and which link-layer mappings exist.
Per-interface parameters are added through augmentation of the
interface data model defined in [RFC8343].

This version of the IP data model supports the Network Management
Datastore Architecture (NMDA) [RFC8342].

1.1. Summary of Changes from RFC 7277

The "ipv4" and "ipv6" subtrees with "config false" data nodes in the
"/interfaces-state/interface" subtree are deprecated. All
"config false" data nodes are now present in the "ipv4" and "ipv6"
subtrees in the "/interfaces/interface" subtree.

Servers that do not implement NMDA or that wish to support clients
that do not implement NMDA MAY implement the deprecated "ipv4" and
"ipv6" subtrees in the "/interfaces-state/interface" subtree.

Bjorklund Standards Track [Page 2]
RFC 8344 YANG IP Management March 2018

1.2. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.

The following terms are defined in [RFC8342] and are not redefined
here:

o client

o server

o configuration

o system state

o intended configuration

o running configuration datastore

o operational state

o operational state datastore

The following terms are defined in [RFC7950] and are not redefined
here:

o augment

o data model

o data node

The terminology for describing YANG data models is found in
[RFC7950].

1.3. Tree Diagrams

Tree diagrams used in this document follow the notation defined in
[RFC8340].

Bjorklund Standards Track [Page 3]
RFC 8344 YANG IP Management March 2018

2. IP Data Model

This document defines the YANG module "ietf-ip", which augments the
"interface&Stewart, et al. Informational [Page 46]
RFC 6458 SCTP Sockets API December 2011

sre_type: This field should be set to SCTP_REMOTE_ERROR.

sre_flags: This field is currently unused.

sre_length: This field is the total length of the notification data,
including the notification header and the contents of sre_data.

sre_error: This value represents one of the Operation Error causes
defined in the SCTP specification [RFC4960], in network byte
order.

sre_assoc_id: The sre_assoc_id field holds the identifier for the
association. All notifications for a given association have the
same association identifier. For a one-to-one style socket, this
field is ignored.

sre_data: This contains the ERROR chunk as defined in Section 3.3.10
of the SCTP specification [RFC4960].

6.1.4. SCTP_SEND_FAILED - DEPRECATED

Please note that this notification is deprecated. Use
SCTP_SEND_FAILED_EVENT instead.

If SCTP cannot deliver a message, it can return back the message as a
notification if the SCTP_SEND_FAILED event is enabled. The
notification has the following format:

struct sctp_send_failed {
uint16_t ssf_type;
uint16_t ssf_flags;
uint32_t ssf_length;
uint32_t ssf_error;
struct sctp_sndrcvinfo ssf_info;
sctp_assoc_t ssf_assoc_id;
uint8_t ssf_data[];
};

ssf_type: This field should be set to SCTP_SEND_FAILED.

ssf_flags: The flag value will take one of the following values:

SCTP_DATA_UNSENT: This value indicates that the data was never
put on the wire.

SCTP_DATA_SENT: This value indicates that the data was put on the
wire. Note that this does not necessarily mean that the data
was (or was not) successfully delivered.

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ssf_length: This field is the total length of the notification data,
including the notification header and the payload in ssf_data.

ssf_error: This value represents the reason why the send failed, and
if set, will be an SCTP protocol error code as defined in
Section 3.3.10 of [RFC4960].

ssf_info: This field includes the ancillary data (struct
sctp_sndrcvinfo) used to send the undelivered message. Regardless
of whether ancillary data is used or not, the ssf_info.sinfo_flags
field indicates whether the complete message or only part of the
message is returned in ssf_data. If only part of the message is
returned, it means that the part that is not present has been sent
successfully to the peer.

If the complete message cannot be sent, the SCTP_DATA_NOT_FRAG
flag is set in ssf_info.sinfo_flags. If the first part of the
message is sent successfully, SCTP_DATA_LAST_FRAG is set. This
means that the tail end of the message is returned in ssf_data.

ssf_assoc_id: The ssf_assoc_id field, ssf_assoc_id, holds the
identifier for the association. All notifications for a given
association have the same association identifier. For a one-to-
one style socket, this field is ignored.

ssf_data: The undelivered message or part of the undelivered message
will be present in the ssf_data field. Note that the
ssf_info.sinfo_flags field as noted above should be used to
determine whether a complete message or just a piece of the
message is present. Note that only user data is present in this
field; any chunk headers or SCTP common headers must be removed by
the SCTP stack.

6.1.5. SCTP_SHUTDOWN_EVENT

When a peer sends a SHUTDOWN, SCTP delivers this notification to
inform the application that it should cease sending data.

struct sctp_shutdown_event {
uint16_t sse_type;
uint16_t sse_flags;
uint32_t sse_length;
sctp_assoc_t sse_assoc_id;
};

sse_type: This field should be set to SCTP_SHUTDOWN_EVENT.

sse_flags: This field is currently unused.

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sse_length: This field is the total length of the notification data,
including the notification header. It will generally be
sizeof(struct sctp_shutdown_event).

sse_assoc_id: The sse_assoc_id field holds the identifier for the
association. All notifications for a given association have the
same association identifier. For a one-to-one style socket, this
field is ignored.

6.1.6. SCTP_ADAPTATION_INDICATION

When a peer sends an Adaptation Layer Indication parameter as
described in [RFC5061], SCTP delivers this notification to inform the
application about the peer's adaptation layer indication.

struct sctp_adaptation_event {
uint16_t sai_type;
uint16_t sai_flags;
uint32_t sai_length;
uint32_t sai_adaptation_ind;
sctp_assoc_t sai_assoc_id;
};

sai_type: This field should be set to SCTP_ADAPTATION_INDICATION.

sai_flags: This field is currently unused.

sai_length: This field is the total length of the notification data,
including the notification header. It will generally be
sizeof(struct sctp_adaptation_event).

sai_adaptation_ind: This field holds the bit array sent by the peer
in the Adaptation Layer Indication parameter.

sai_assoc_id: The sai_assoc_id field holds the identifier for the
association. All notifications for a given association have the
same association identifier. For a one-to-one style socket, this
field is ignored.

6.1.7. SCTP_PARTIAL_DELIVERY_EVENT

When a receiver is engaged in a partial delivery of a message, this
notification will be used to indicate various events.

struct sctp_pdapi_event {
uint16_t pdapi_type;
uint16_t pdapi_flags;
uint32_t pdapi_length;

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uint32_t pdapi_indication;
uint32_t pdapi_stream;
uint32_t pdapi_seq;
sctp_assoc_t pdapi_assoc_id;
};

pdapi_type: This field should be set to SCTP_PARTIAL_DELIVERY_EVENT.

pdapi_flags: This field is currently unused.

pdapi_length: This field is the total length of the notification
data, including the notification header. It will generally be
sizeof(struct sctp_pdapi_event).

pdapi_indication: This field holds the indication being sent to the
application. Currently, there is only one defined value:

SCTP_PARTIAL_DELIVERY_ABORTED: This indicates that the partial
delivery of a user message has been aborted. This happens, for
example, if an association is aborted while a partial delivery
is going on or the user message gets abandoned using PR-SCTP
while the partial delivery of this message is going on.

pdapi_stream: This field holds the stream on which the partial
delivery event happened.

pdapi_seq: This field holds the stream sequence number that was
being partially delivered.

pdapi_assoc_id: The pdapi_assoc_id field holds the identifier for
the association. All notifications for a given association have
the same association identifier. For a one-to-one style socket,
this field is ignored.

6.1.8. SCTP_AUTHENTICATION_EVENT

[RFC4895] defines an extension to authenticate SCTP messages. The
following notification is used to report different events relating to
the use of this extension.

struct sctp_authkey_event {
uint16_t auth_type;
uint16_t auth_flags;
uint32_t auth_length;
uint16_t auth_keynumber;
uint32_t auth_indication;
sctp_assoc_t auth_assoc_id;
};

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auth_type: This field should be set to SCTP_AUTHENTICATION_EVENT.

auth_flags: This field is currently unused.

auth_length: This field is the total length of the notification
data, including the notification header. It will generally be
sizeof(struct sctp_authkey_event).

auth_keynumber: This field holds the key number for the affected key
indicated in the event (depends on auth_indication).

auth_indication: This field holds the error or indication being
reported. The following values are currently defined:

SCTP_AUTH_NEW_KEY: This report indicates that a new key has been
made active (used for the first time by the peer) and is now
the active key. The auth_keynumber field holds the user-
specified key number.

SCTP_AUTH_NO_AUTH: This report indicates that the peer does not
support SCTP authentication as defined in [RFC4895].

SCTP_AUTH_FREE_KEY: This report indicates that the SCTP
implementation will no longer use the key identifier specified
in auth_keynumber.

auth_assoc_id: The auth_assoc_id field holds the identifier for the
association. All notifications for a given association have the
same association identifier. For a one-to-one style socket, this
field is ignored.

6.1.9. SCTP_SENDER_DRY_EVENT

When the SCTP stack has no more user data to send or retransmit, this
notification is given to the user. Also, at the time when a user app
subscribes to this event, if there is no data to be sent or
retransmit, the stack will immediately send up this notification.

struct sctp_sender_dry_event {
uint16_t sender_dry_type;
uint16_t sender_dry_flags;
uint32_t sender_dry_length;
sctp_assoc_t sender_dry_assoc_id;
};

sender_dry_type: This field should be set to SCTP_SENDER_DRY_EVENT.

sender_dry_flags: This field is currently unused.

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sender_dry_length: This field is the total length of the
notification data, including the notification header. It will
generally be sizeof(struct sctp_sender_dry_event).

sender_dry_assoc_id: The sender_dry_assoc_id field holds the
identifier for the association. All notifications for a given
association have the same association identifier. For a one-to-
one style socket, this field is ignored.

6.1.10. SCTP_NOTIFICATIONS_STOPPED_EVENT

SCTP notifications, when subscribed to, are reliable. They are
always delivered as long as there is space in the socket receive
buffer. However, if an implementation experiences a notification
storm, it may run out of socket buffer space. When this occurs, it
may wish to disable notifications. If the implementation chooses to
do this, it will append a final notification
SCTP_NOTIFICATIONS_STOPPED_EVENT. This notification is a union
sctp_notification, where only the sctp_tlv structure (see the union
above) is used. It only contains this type in the sn_type field, the
sn_length field set to the size of an sctp_tlv structure, and the
sn_flags set to 0. If an application receives this notification, it
will need to re-subscribe to any notifications of interest to it,
except for the sctp_data_io_event (note that SCTP_EVENTS is
deprecated).

An endpoint is automatically subscribed to this event as soon as it
is subscribed to any event other than data io events.

6.1.11. SCTP_SEND_FAILED_EVENT

If SCTP cannot deliver a message, it can return back the message as a
notification if the SCTP_SEND_FAILED_EVENT event is enabled. The
notification has the following format:

struct sctp_send_failed_event {
uint16_t ssfe_type;
uint16_t ssfe_flags;
uint32_t ssfe_length;
uint32_t ssfe_error;
struct sctp_sndinfo ssfe_info;
sctp_assoc_t ssfe_assoc_id;
uint8_t ssfe_data[];
};

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ssfe_type: This field should be set to SCTP_SEND_FAILED_EVENT.

ssfe_flags: The flag value will take one of the following values:

SCTP_DATA_UNSENT: This value indicates that the data was never
put on the wire.

SCTP_DATA_SENT: This value indicates that the data was put on the
wire. Note that this does not necessarily mean that the data
was (or was not) successfully delivered.

ssfe_length: This field is the total length of the notification
data, including the notification header and the payload in
ssf_data.

ssfe_error: This value represents the reason why the send failed,
and if set, will be an SCTP protocol error code as defined in
Section 3.3.10 of [RFC4960].

ssfe_info: This field includes the ancillary data (struct
sctp_sndinfo) used to send the undelivered message. Regardless of
whether ancillary data is used or not, the ssfe_info.sinfo_flags
field indicates whether the complete message or only part of the
message is returned in ssf_data. If only part of the message is
returned, it means that the part that is not present has been sent
successfully to the peer.

If the complete message cannot be sent, the SCTP_DATA_NOT_FRAG
flag is set in ssfe_info.sinfo_flags. If the first part of the
message is sent successfully, SCTP_DATA_LAST_FRAG is set. This
means that the tail end of the message is returned in ssf_data.

ssfe_assoc_id: The ssfe_assoc_id field, ssf_assoc_id, holds the
identifier for the association. All notifications for a given
association have the same association identifier. For a one-to-
one style socket, this field is ignored.

ssfe_data: The undelivered message or part of the undelivered
message will be present in the ssf_data field. Note that the
ssf_info.sinfo_flags field as noted above should be used to
determine whether a complete message or just a piece of the
message is present. Note that only user data is present in this
field; any chunk headers or SCTP common headers must be removed by
the SCTP stack.

Stewart, et al. Informational [Page 53]
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6.2. Notification Interest Options

6.2.1. SCTP_EVENTS Option - DEPRECATED

Please note that this option is deprecated. Use the SCTP_EVENT
option described in Section 6.2.2 instead.

To receive SCTP event notifications, an application registers its
interest by setting the SCTP_EVENTS socket option. The application
then uses recvmsg() to retrieve notifications. A notification is
stored in the data part (msg_iov) of the msghdr structure. The
socket option uses the following structure:

struct sctp_event_subscribe {
uint8_t sctp_data_io_event;
uint8_t sctp_association_event;
uint8_t sctp_address_event;
uint8_t sctp_send_failure_event;
uint8_t sctp_peer_error_event;
uint8_t sctp_shutdown_event;
uint8_t sctp_partial_delivery_event;
uint8_t sctp_adaptation_layer_event;
uint8_t sctp_authentication_event;
uint8_t sctp_sender_dry_event;
};

sctp_data_io_event: Setting this flag to 1 will cause the reception
of SCTP_SNDRCV information on a per-message basis. The
application will need to use the recvmsg() interface so that it
can receive the event information contained in the msg_control
field. Setting the flag to 0 will disable the reception of the
message control information. Note that this flag is not really a
notification and is stored in the ancillary data (msg_control),
not in the data part (msg_iov).

sctp_association_event: Setting this flag to 1 will enable the
reception of association event notifications. Setting the flag to
0 will disable association event notifications.

sctp_address_event: Setting this flag to 1 will enable the reception
of address event notifications. Setting the flag to 0 will
disable address event notifications.

sctp_send_failure_event: Setting this flag to 1 will enable the
reception of send failure event notifications. Setting the flag
to 0 will disable send failure event notifications.

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sctp_peer_error_event: Setting this flag to 1 will enable the
reception of peer error event notifications. Setting the flag to
0 will disable peer error event notifications.

sctp_shutdown_event: Setting this flag to 1 will enable the
reception of shutdown event notifications. Setting the flag to 0
will disable shutdown event notifications.

sctp_partial_delivery_event: Setting this flag to 1 will enable the
reception of partial delivery event notifications. Setting the
flag to 0 will disable partial delivery event notifications.

sctp_adaptation_layer_event: Setting this flag to 1 will enable the
reception of adaptation layer event notifications. Setting the
flag to 0 will disable adaptation layer event notifications.

sctp_authentication_event: Setting this flag to 1 will enable the
reception of authentication layer event notifications. Setting
the flag to 0 will disable authentication layer event
notifications.

sctp_sender_dry_event: Setting this flag to 1 will enable the
reception of sender dry event notifications. Setting the flag to
0 will disable sender dry event notifications.

An example where an application would like to receive data_io_events
and association_events but no others would be as follows:

{
struct sctp_event_subscribe events;

memset(&events, 0, sizeof(events));

events.sctp_data_io_event = 1;
events.sctp_association_event = 1;

setsockopt(sd, IPPROTO_SCTP, SCTP_EVENTS, &events, sizeof(events));
}

Note that for one-to-many style SCTP sockets, the caller of recvmsg()
receives ancillary data and notifications for all associations bound
to the file descriptor. For one-to-one style SCTP sockets, the
caller receives ancillary data and notifications only for the single
association bound to the file descriptor.

By default, both the one-to-one style and the one-to-many style
socket do not subscribe to any notification.

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6.2.2. SCTP_EVENT Option

The SCTP_EVENTS socket option has one issue for future compatibility.
As new features are added, the structure (sctp_event_subscribe) must
be expanded. This can cause an application binary interface (ABI)
issue unless an implementation has added padding at the end of the
structure. To avoid this problem, SCTP_EVENTS has been deprecated
and a new socket option SCTP_EVENT has taken its place. The option
is used with the following structure:

struct sctp_event {
sctp_assoc_t se_assoc_id;
uint16_t se_type;
uint8_t se_on;
};

se_assoc_id: The se_assoc_id field is ignored for one-to-one style
sockets. For one-to-many style sockets, this field can be a
particular association identifier or SCTP_{FUTURE|CURRENT|
ALL}_ASSOC.

se_type: The se_type field can be filled with any value that would
show up in the respective sn_type field (in the sctp_tlv structure
of the notification).

se_on: The se_on field is set to 1 to turn on an event and set to 0
to turn off an event.

To use this option, the user fills in this structure and then calls
setsockopt() to turn on or off an individual event. The following is
an example use of this option:

{
struct sctp_event event;

memset(&event, 0, sizeof(event));

event.se_assoc_id = SCTP_FUTURE_ASSOC;
event.se_type = SCTP_SENDER_DRY_EVENT;
event.se_on = 1;
setsockopt(sd, IPPROTO_SCTP, SCTP_EVENT, &event, sizeof(event));
}

By default, both the one-to-one style and the one-to-many style
socket do not subscribe to any notification.

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7. Common Operations for Both Styles

7.1. send(), recv(), sendto(), and recvfrom()

Applications can use send() and sendto() to transmit data to the peer
of an SCTP endpoint. recv() and recvfrom() can be used to receive
data from the peer.

The function prototypes are

ssize_t send(int sd,
const void *msg,
size_t len,
int flags);

ssize_t sendto(int sd,
const void *msg,
size_t len,
int flags,
const struct sockaddr *to,
socklen_t tolen);

ssize_t recv(int sd,
void *buf,
size_t len,
int flags);

ssize_t recvfrom(int sd,
void *buf,
size_t len,
int flags,
struct sockaddr *from,
socklen_t *fromlen);

and the arguments are

sd: The socket descriptor of an SCTP endpoint.

msg: The message to be sent.

len: The size of the message or the size of the buffer.

to: One of the peer addresses of the association to be used to send
the message.

tolen: The size of the address.

buf: The buffer to store a received message.

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from: The buffer to store the peer address used to send the received
message.

fromlen: The size of the from address.

flags: (described below).

These calls give access to only basic SCTP protocol features. If
either peer in the association uses multiple streams, or sends
unordered data, these calls will usually be inadequate and may
deliver the data in unpredictable ways.

SCTP has the concept of multiple streams in one association. The
above calls do not allow the caller to specify on which stream a
message should be sent. The system uses stream 0 as the default
stream for send() and sendto(). recv() and recvfrom() return data
from any stream, but the caller cannot distinguish the different
streams. This may result in data seeming to arrive out of order.
Similarly, if a DATA chunk is sent unordered, recv() and recvfrom()
provide no indication.

SCTP is message based. The msg buffer above in send() and sendto()
is considered to be a single message. This means that if the caller
wants to send a message that is composed by several buffers, the
caller needs to combine them before calling send() or sendto().
Alternately, the caller can use sendmsg() to do that without
combining them. Sending a message using send() or sendto() is atomic
unless explicit EOR marking is enabled on the socket specified by sd.
Using sendto() on a non-connected one-to-one style socket for
implicit connection setup may or may not work, depending on the SCTP
implementation. recv() and recvfrom() cannot distinguish message
boundaries (i.e., there is no way to observe the MSG_EOR flag to
detect partial delivery).

When receiving, if the buffer supplied is not large enough to hold a
complete message, the receive call acts like a stream socket and
returns as much data as will fit in the buffer.

Note that the send() and recv() calls may not be used for a one-to-
many style socket.

Note that if an application calls a send() or sendto() function with
no user data, the SCTP implementation should reject the request with
an appropriate error message. An implementation is not allowed to
send a DATA chunk with no user data [RFC4960].

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7.2. setsockopt() and getsockopt()

Applications use setsockopt() and getsockopt() to set or retrieve
socket options. Socket options are used to change the default
behavior of socket calls. They are described in Section 8.

The function prototypes are

int getsockopt(int sd,
int level,
int optname,
void *optval,
socklen_t *optlen);

and

int setsockopt(int sd,
int level,
int optname,
const void *optval,
socklen_t optlen);

and the arguments are

sd: The socket descriptor.

level: Set to IPPROTO_SCTP for all SCTP options.

optname: The option name.

optval: The buffer to store the value of the option.

optlen: The size of the buffer (or the length of the option
returned).

These functions return 0 on success and -1 in case of an error.

All socket options set on a one-to-one style listening socket also
apply to all future accepted sockets. For one-to-many style sockets,
often a socket option will pass a structure that includes an assoc_id
field. This field can be filled with the association identifier of a
particular association and unless otherwise specified can be filled
with one of the following constants:

SCTP_FUTURE_ASSOC: Specifies that only future associations created
after this socket option will be affected by this call.

Stewart, et al. Informational [Page 59]
RFC 6458 SCTP Sockets API December 2011

SCTP_CURRENT_ASSOC: Specifies that only currently existing
associations will be affected by this call, and future
associations will still receive the previous default value.

SCTP_ALL_ASSOC: Specifies that all current and future associations
will be affected by this call.

7.3. read() and write()

Applications can use read() and write() to receive and send data from
and to a peer. They have the same semantics as recv() and send(),
except that the flags parameter cannot be used.

7.4. getsockname()

Applications use getsockname() to retrieve the locally bound socket
address of the specified socket. This is especially useful if the
caller let SCTP choose a local port. This call is for single-homed
endpoints. It does not work well with multi-homed endpoints. See
Section 9.5 for a multi-homed version of the call.

The function prototype is

int getsockname(int sd,
struct sockaddr *address,
socklen_t *len);

and the arguments are

sd: The socket descriptor to be queried.

address: On return, one locally bound address (chosen by the SCTP
stack) is stored in this buffer. If the socket is an IPv4 socket,
the address will be IPv4. If the socket is an IPv6 socket, the
address will be either an IPv6 or IPv4 address.

len: The caller should set the length of the address here. On
return, this is set to the length of the returned address.

getsockname() returns 0 on success and -1 in case of an error.

If the actual length of the address is greater than the length of the
supplied sockaddr structure, the stored address will be truncated.

If the socket has not been bound to a local name, the value stored in
the object pointed to by address is unspecified.

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7.5. Implicit Association Setup

The application can begin sending and receiving data using the
sendmsg()/recvmsg() or sendto()/recvfrom() calls, without going
through any explicit association setup procedures (i.e., no connect()
calls required).

Whenever sendmsg() or sendto() is called and the SCTP stack at the
sender finds that no association exists between the sender and the
intended receiver (identified by the address passed either in the
msg_name field of the msghdr structure in the sendmsg() call or the
dest_addr field in the sendto() call), the SCTP stack will
automatically set up an association to the intended receiver.

Upon successful association setup, an SCTP_COMM_UP notification will
be dispatched to the socket at both the sender and receiver side.
This notification can be read by the recvmsg() system call (see
Section 3.1.4).

Note that if the SCTP stack at the sender side supports bundling, the
first user message may be bundled with the COOKIE ECHO message
[RFC4960].

When the SCTP stack sets up a new association implicitly, the
SCTP_INIT type ancillary data may also be passed along (see
Section 5.3.1 for details of the data structures) to change some
parameters used in setting up a new association.

If this information is not present in the sendmsg() call, or if the
implicit association setup is triggered by a sendto() call, the
default association initialization parameters will be used. These
default association parameters may be set with respective
setsockopt() calls or be left to the system defaults.

Implicit association setup cannot be initiated by send() calls.

8. Socket Options

The following subsection describes various SCTP-level socket options
that are common to both styles. SCTP associations can be
multi-homed. Therefore, certain option parameters include a
sockaddr_storage structure to select to which peer address the option
should be applied.

For the one-to-many style sockets, an sctp_assoc_t (association
identifier) parameter is used to identify the association instance
that the operation affects. So it must be set when using this style.

Stewart, et al. Informational [Page 61]
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For the one-to-one style sockets and branched-off one-to-many style
sockets (see Section 9.2), this association ID parameter is ignored.

Note that socket- or IP-level options are set or retrieved per
socket. This means that for one-to-many style sockets, the options
will be applied to all associations (similar to using SCTP_ALL_ASSOC
as the association identifier) belonging to the socket. For the one-
to-one style, these options will be applied to all peer addresses of
the association controlled by the socket. Applications should be
careful in setting those options.

For some IP stacks, getsockopt() is read-only, so a new interface
will be needed when information must be passed both into and out of
the SCTP stack. The syntax for sctp_opt_info() is

int sctp_opt_info(int sd,
sctp_assoc_t id,
int opt,
void *arg,
socklen_t *size);

The sctp_opt_info() call is a replacement for getsockopt() only and
will not set any options associated with the specified socket. A
setsockopt() call must be used to set any writable option.

For one-to-many style sockets, id specifies the association to query.
For one-to-one style sockets, id is ignored. For one-to-many style
sockets, any association identifier in the structure provided as arg
is ignored, and id takes precedence.

Note that SCTP_CURRENT_ASSOC and SCTP_ALL_ASSOC cannot be used with
sctp_opt_info() or in getsockopt() calls. Using them will result in
an error (returning -1 and errno set to EINVAL). SCTP_FUTURE_ASSOC
can be used to query information for future associations.

The field opt specifies which SCTP socket option to get. It can get
any socket option currently supported that requests information
(either read/write options or read-only) such as

SCTP_RTOINFO

SCTP_ASSOCINFO

SCTP_PRIMARY_ADDR

SCTP_PEER_ADDR_PARAMS

SCTP_DEFAULT_SEND_PARAM

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SCTP_MAX_SEG

SCTP_AUTH_ACTIVE_KEY

SCTP_DELAYED_SACK

SCTP_MAX_BURST

SCTP_CONTEXT

SCTP_EVENT

SCTP_DEFAULT_SNDINFO

SCTP_DEFAULT_PRINFO

SCTP_STATUS

SCTP_GET_PEER_ADDR_INFO

SCTP_PEER_AUTH_CHUNKS

SCTP_LOCAL_AUTH_CHUNKS

The arg field is an option-specific structure buffer provided by the
caller. See the rest of this section for more information on these
options and option-specific structures.

sctp_opt_info() returns 0 on success, or on failure returns -1 and
sets errno to the appropriate error code.

8.1. Read/Write Options

8.1.1. Retransmission Timeout Parameters (SCTP_RTOINFO)

The protocol parameters used to initialize and limit the
retransmission timeout (RTO) are tunable. See [RFC4960] for more
information on how these parameters are used in RTO calculation.

The following structure is used to access and modify these
parameters:

struct sctp_rtoinfo {
sctp_assoc_t srto_assoc_id;
uint32_t srto_initial;
uint32_t srto_max;
uint32_t srto_min;
};

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srto_assoc_id: This parameter is ignored for one-to-one style
sockets. For one-to-many style sockets, the application may fill
in an association identifier or SCTP_FUTURE_ASSOC. It is an error
to use SCTP_{CURRENT|ALL}_ASSOC in srto_assoc_id.

srto_initial: This parameter contains the initial RTO value.

srto_max and srto_min: These parameters contain the maximum and
minimum bounds for all RTOs.

All times are given in milliseconds. A value of 0, when modifying
the parameters, indicates that the current value should not be
changed.

To access or modify these parameters, the application should call
getsockopt() or setsockopt(), respectively, with the option name
SCTP_RTOINFO.

8.1.2. Association Parameters (SCTP_ASSOCINFO)

This option is used to both examine and set various association and
endpoint parameters. See [RFC4960] for more information on how these
parameters are used.

The following structure is used to access and modify these
parameters:

struct sctp_assocparams {
sctp_assoc_t sasoc_assoc_id;
uint16_t sasoc_asocmaxrxt;
uint16_t sasoc_number_peer_destinations;
uint32_t sasoc_peer_rwnd;
uint32_t sasoc_local_rwnd;
uint32_t sasoc_cookie_life;
};

sasoc_assoc_id: This parameter is ignored for one-to-one style
sockets. For one-to-many style sockets, the application may fill
in an association identifier or SCTP_FUTURE_ASSOC. It is an error
to use SCTP_{CURRENT|ALL}_ASSOC in sasoc_assoc_id.

sasoc_asocmaxrxt: This parameter contains the maximum retransmission
attempts to make for the association.

sasoc_number_peer_destinations: This parameter is the number of
destination addresses that the peer has.

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sasoc_peer_rwnd: This parameter holds the current value of the
peer's rwnd (reported in the last selective acknowledgment (SACK))
minus any outstanding data (i.e., data in flight).

sasoc_local_rwnd: This parameter holds the last reported rwnd that
was sent to the peer.

sasoc_cookie_life: This parameter is the association's cookie life
value used when issuing cookies.

The value of sasoc_peer_rwnd is meaningless when examining endpoint
information (i.e., it is only valid when examining information on a
specific association).

All time values are given in milliseconds. A value of 0, when
modifying the parameters, indicates that the current value should not
be changed.

The values of sasoc_asocmaxrxt and sasoc_cookie_life may be set on
either an endpoint or association basis. The rwnd and destination
counts (sasoc_number_peer_destinations, sasoc_peer_rwnd,
sasoc_local_rwnd) are not settable, and any value placed in these is
ignored.

To access or modify these parameters, the application should call
getsockopt() or setsockopt(), respectively, with the option name
SCTP_ASSOCINFO.

The maximum number of retransmissions before an address is considered
unreachable is also tunable, but is address-specific, so it is
covered in a separate option. If an application attempts to set the
value of the association's maximum retransmission parameter to more
than the sum of all maximum retransmission parameters, setsockopt()
may return an error. The reason for this, from Section 8.2 of
[RFC4960], is as follows:

Note: When configuring the SCTP endpoint, the user should avoid
having the value of 'Association.Max.Retrans' (sasoc_maxrxt in
this option) larger than the summation of the 'Path.Max.Retrans'
(see spp_pathmaxrxt in Section 8.1.12) of all of the destination
addresses for the remote endpoint. Otherwise, all of the
destination addresses may become inactive while the endpoint still
considers the peer endpoint reachable.

Stewart, et al. Informational [Page 65]
RFC 6458 SCTP Sockets API December 2011quot; lists defined in the "ietf-interfaces" module [RFC8343]
with IP-specific data nodes.

The data model has the following structure for IP data nodes per
interface, excluding the deprecated data nodes:

module: ietf-ip
augment /if:interfaces/if:interface:
+--rw ipv4!
| +--rw enabled? boolean
| +--rw forwarding? boolean
| +--rw mtu? uint16
| +--rw address* [ip]
| | +--rw ip inet:ipv4-address-no-zone
| | +--rw (subnet)
| | | +--:(prefix-length)
| | | | +--rw prefix-length? uint8
| | | +--:(netmask)
| | | +--rw netmask? yang:dotted-quad
| | | {ipv4-non-contiguous-netmasks}?
| | +--ro origin? ip-address-origin
| +--rw neighbor* [ip]
| +--rw ip inet:ipv4-address-no-zone
| +--rw link-layer-address yang:phys-address
| +--ro origin? neighbor-origin
+--rw ipv6!
+--rw enabled? boolean
+--rw forwarding? boolean
+--rw mtu? uint32
+--rw address* [ip]
| +--rw ip inet:ipv6-address-no-zone
| +--rw prefix-length uint8
| +--ro origin? ip-address-origin
| +--ro status? enumeration
+--rw neighbor* [ip]
| +--rw ip inet:ipv6-address-no-zone
| +--rw link-layer-address yang:phys-address
| +--ro origin? neighbor-origin
| +--ro is-router? empty
| +--ro state? enumeration
+--rw dup-addr-detect-transmits? uint32

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+--rw autoconf
+--rw create-global-addresses? boolean
+--rw create-temporary-addresses? boolean
| {ipv6-privacy-autoconf}?
+--rw temporary-valid-lifetime? uint32
| {ipv6-privacy-autoconf}?
+--rw temporary-preferred-lifetime? uint32
{ipv6-privacy-autoconf}?

The data model defines two containers per interface -- "ipv4" and
"ipv6", representing the IPv4 and IPv6 address families. In each
container, there is a leaf "enabled" that controls whether or not the
address family is enabled on that interface, and a leaf "forwarding"
that controls whether or not IP packet forwarding for the address
family is enabled on the interface. In each container, there is also
a list of addresses and a list of mappings from IP addresses to
link-layer addresses.

3. Relationship to the IP-MIB

If the device implements the IP-MIB [RFC4293], each entry in the
"ipv4/address" and "ipv6/address" lists is mapped to one
ipAddressEntry, where the ipAddressIfIndex refers to the "address"
entry's interface.

The IP-MIB defines objects to control IPv6 Router Advertisement
messages. The corresponding YANG data nodes are defined in
[RFC8022].

The entries in "ipv4/neighbor" and "ipv6/neighbor" are mapped to
ipNetToPhysicalTable.

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The following table lists the YANG data nodes with corresponding
objects in the IP-MIB.

YANG Interface Data Nodes and Related IP-MIB Objects

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4. IP Management YANG Module

This module imports typedefs from [RFC6991] and [RFC8343], and it
references [RFC791], [RFC826], [RFC4861], [RFC4862], [RFC4941],
[RFC7217], and [RFC8200].

<CODE BEGINS> file "ietf-ip@2018-02-22.yang"
module ietf-ip {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-ip";
prefix ip;

import ietf-interfaces {
prefix if;
}
import ietf-inet-types {
prefix inet;
}
import ietf-yang-types {
prefix yang;
}

organization
"IETF NETMOD (Network Modeling) Working Group";

contact
"WG Web: <https://datatracker.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org>

Editor: Martin Bjorklund
<mailto:mbj@tail-f.com>";
description
"This module contains a collection of YANG definitions for
managing IP implementations.

Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).

This version of this YANG module is part of RFC 8344; see
the RFC itself for full legal notices.";

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revision 2018-02-22 {
description
"Updated to support NMDA.";
reference
"RFC 8344: A YANG Data Model for IP Management";
}

revision 2014-06-16 {
description
"Initial revision.";
reference
"RFC 7277: A YANG Data Model for IP Management";
}

/*
* Features
*/

feature ipv4-non-contiguous-netmasks {
description
"Indicates support for configuring non-contiguous
subnet masks.";
}

feature ipv6-privacy-autoconf {
description
"Indicates support for privacy extensions for stateless address
autoconfiguration in IPv6.";
reference
"RFC 4941: Privacy Extensions for Stateless Address
Autoconfiguration in IPv6";
}

/*
* Typedefs
*/

typedef ip-address-origin {
type enumeration {
enum other {
description
"None of the following.";
}

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enum static {
description
"Indicates that the address has been statically
configured -- for example, using the Network Configuration
Protocol (NETCONF) or a command line interface.";
}
enum dhcp {
description
"Indicates an address that has been assigned to this
system by a DHCP server.";
}
enum link-layer {
description
"Indicates an address created by IPv6 stateless
autoconfiguration that embeds a link-layer address in its
interface identifier.";
}
enum random {
description
"Indicates an address chosen by the system at
random, e.g., an IPv4 address within 169.254/16, a
temporary address as described in RFC 4941, or a
semantically opaque address as described in RFC 7217.";
reference
"RFC 4941: Privacy Extensions for Stateless Address
Autoconfiguration in IPv6
RFC 7217: A Method for Generating Semantically Opaque
Interface Identifiers with IPv6 Stateless
Address Autoconfiguration (SLAAC)";
}
}
description
"The origin of an address.";
}

typedef neighbor-origin {
type enumeration {
enum other {
description
"None of the following.";
}
enum static {
description
"Indicates that the mapping has been statically
configured -- for example, using NETCONF or a command line
interface.";
}

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enum dynamic {
description
"Indicates that the mapping has been dynamically resolved
using, for example, IPv4 ARP or the IPv6 Neighbor
Discovery protocol.";
}
}
description
"The origin of a neighbor entry.";
}

/*
* Data nodes
*/

augment "/if:interfaces/if:interface" {
description
"IP parameters on interfaces.

If an interface is not capable of running IP, the server
must not allow the client to configure these parameters.";

container ipv4 {
presence
"Enables IPv4 unless the 'enabled' leaf
(which defaults to 'true') is set to 'false'";
description
"Parameters for the IPv4 address family.";

leaf enabled {
type boolean;
default true;
description
"Controls whether IPv4 is enabled or disabled on this
interface. When IPv4 is enabled, this interface is
connected to an IPv4 stack, and the interface can send
and receive IPv4 packets.";
}
leaf forwarding {
type boolean;
default false;
description
"Controls IPv4 packet forwarding of datagrams received by,
but not addressed to, this interface. IPv4 routers
forward datagrams. IPv4 hosts do not (except those
source-routed via the host).";
}

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leaf mtu {
type uint16 {
range "68..max";
}
units "octets";
description
"The size, in octets, of the largest IPv4 packet that the
interface will send and receive.

The server may restrict the allowed values for this leaf,
depending on the interface's type.

If this leaf is not configured, the operationally used MTU
depends on the interface's type.";
reference
"RFC 791: Internet Protocol";
}
list address {
key "ip";
description
"The list of IPv4 addresses on the interface.";

leaf ip {
type inet:ipv4-address-no-zone;
description
"The IPv4 address on the interface.";
}
choice subnet {
mandatory true;
description
"The subnet can be specified as a prefix length or,
if the server supports non-contiguous netmasks, as
a netmask.";
leaf prefix-length {
type uint8 {
range "0..32";
}
description
"The length of the subnet prefix.";
}
leaf netmask {
if-feature ipv4-non-contiguous-netmasks;
type yang:dotted-quad;
description
"The subnet specified as a netmask.";
}
}

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leaf origin {
type ip-address-origin;
config false;
description
"The origin of this address.";
}
}
list neighbor {
key "ip";
description
"A list of mappings from IPv4 addresses to
link-layer addresses.

Entries in this list in the intended configuration are
used as static entries in the ARP Cache.

In the operational state, this list represents the ARP
Cache.";
reference
"RFC 826: An Ethernet Address Resolution Protocol";

leaf ip {
type inet:ipv4-address-no-zone;
description
"The IPv4 address of the neighbor node.";
}
leaf link-layer-address {
type yang:phys-address;
mandatory true;
description
"The link-layer address of the neighbor node.";
}
leaf origin {
type neighbor-origin;
config false;
description
"The origin of this neighbor entry.";
}
}
}

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container ipv6 {
presence
"Enables IPv6 unless the 'enabled' leaf
(which defaults to 'true') is set to 'false'";
description
"Parameters for the IPv6 address family.";

leaf enabled {
type boolean;
default true;
description
"Controls whether IPv6 is enabled or disabled on this
interface. When IPv6 is enabled, this interface is
connected to an IPv6 stack, and the interface can send
and receive IPv6 packets.";
}
leaf forwarding {
type boolean;
default false;
description
"Controls IPv6 packet forwarding of datagrams received by,
but not addressed to, this interface. IPv6 routers
forward datagrams. IPv6 hosts do not (except those
source-routed via the host).";
reference
"RFC 4861: Neighbor Discovery for IP version 6 (IPv6)
Section 6.2.1, IsRouter";
}
leaf mtu {
type uint32 {
range "1280..max";
}
units "octets";
description
"The size, in octets, of the largest IPv6 packet that the
interface will send and receive.

The server may restrict the allowed values for this leaf,
depending on the interface's type.

If this leaf is not configured, the operationally used MTU
depends on the interface's type.";
reference
"RFC 8200: Internet Protocol, Version 6 (IPv6)
Specification
Section 5";
}

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list address {
key "ip";
description
"The list of IPv6 addresses on the interface.";

leaf ip {
type inet:ipv6-address-no-zone;
description
"The IPv6 address on the interface.";
}
leaf prefix-length {
type uint8 {
range "0..128";
}
mandatory true;
description
"The length of the subnet prefix.";
}
leaf origin {
type ip-address-origin;
config false;
description
"The origin of this address.";
}
leaf status {
type enumeration {
enum preferred {
description
"This is a valid address that can appear as the
destination or source address of a packet.";
}
enum deprecated {
description
"This is a valid but deprecated address that should
no longer be used as a source address in new
communications, but packets addressed to such an
address are processed as expected.";
}
enum invalid {
description
"This isn't a valid address, and it shouldn't appear
as the destination or source address of a packet.";
}

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enum inaccessible {
description
"The address is not accessible because the interface
to which this address is assigned is not
operational.";
}
enum unknown {
description
"The status cannot be determined for some reason.";
}
enum tentative {
description
"The uniqueness of the address on the link is being
verified. Addresses in this state should not be
used for general communication and should only be
used to determine the uniqueness of the address.";
}
enum duplicate {
description
"The address has been determined to be non-unique on
the link and so must not be used.";
}
enum optimistic {
description
"The address is available for use, subject to
restrictions, while its uniqueness on a link is
being verified.";
}
}
config false;
description
"The status of an address. Most of the states correspond
to states from the IPv6 Stateless Address
Autoconfiguration protocol.";
reference
"RFC 4293: Management Information Base for the
Internet Protocol (IP)
- IpAddressStatusTC
RFC 4862: IPv6 Stateless Address Autoconfiguration";
}
}

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list neighbor {
key "ip";
description
&

8.1.3. Initialization Parameters (SCTP_INITMSG)

Applications can specify protocol parameters for the default
association initialization. The structure used to access and modify
these parameters is defined in Section 5.3.1. The option name
argument to setsockopt() and getsockopt() is SCTP_INITMSG.

Setting initialization parameters is effective only on an unconnected
socket (for one-to-many style sockets, only future associations are
affected by the change).

8.1.4. SO_LINGER

An application can use this option to perform the SCTP ABORT
primitive. This option affects all associations related to the
socket.

The linger option structure is

struct linger {
int l_onoff; /* option on/off */
int l_linger; /* linger time */
};

To enable the option, set l_onoff to 1. If the l_linger value is set
to 0, calling close() is the same as the ABORT primitive. If the
value is set to a negative value, the setsockopt() call will return
an error. If the value is set to a positive value linger_time, the
close() can be blocked for at most linger_time. Please note that the
time unit is in seconds, according to POSIX, but might be different
on specific platforms. If the graceful shutdown phase does not
finish during this period, close() will return, but the graceful
shutdown phase will continue in the system.

Note that this is a socket-level option, not an SCTP-level option.
When using this option, an application must specify a level of
SOL_SOCKET in the call.

8.1.5. SCTP_NODELAY

This option turns on/off any Nagle-like algorithm. This means that
packets are generally sent as soon as possible, and no unnecessary
delays are introduced, at the cost of more packets in the network.
In particular, not using any Nagle-like algorithm might reduce the
bundling of small user messages in cases where this would require an
additional delay.

Turning this option on disables any Nagle-like algorithm.

Stewart, et al. Informational [Page 66]
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This option expects an integer boolean flag, where a non-zero value
turns on the option, and a zero value turns off the option.

8.1.6. SO_RCVBUF

This option sets the receive buffer size in octets. For SCTP one-to-
one style sockets, this option controls the receiver window size.
For one-to-many style sockets, the meaning is implementation
dependent. It might control the receive buffer for each association
bound to the socket descriptor, or it might control the receive
buffer for the whole socket. This option expects an integer.

Note that this is a socket-level option, not an SCTP-level option.
When using this option, an application must specify a level of
SOL_SOCKET in the call.

8.1.7. SO_SNDBUF

This option sets the send buffer size. For SCTP one-to-one style
sockets, this option controls the amount of data SCTP may have
waiting in internal buffers to be sent. This option therefore bounds
the maximum size of data that can be sent in a single send call. For
one-to-many style sockets, the effect is the same, except that it
applies to one or all associations (see Section 3.3) bound to the
socket descriptor used in the setsockopt() or getsockopt() call. The
option applies to each association's window size separately. This
option expects an integer.

Note that this is a socket-level option, not an SCTP-level option.
When using this option, an application must specify a level of
SOL_SOCKET in the call.

8.1.8. Automatic Close of Associations (SCTP_AUTOCLOSE)

This socket option is applicable to the one-to-many style socket
only. When set, it will cause associations that are idle for more
than the specified number of seconds to automatically close using the
graceful shutdown procedure. An idle association is defined as an
association that has not sent or received user data. The special
value of '0' indicates that no automatic close of any association
should be performed; this is the default value. This option expects
an integer defining the number of seconds of idle time before an
association is closed.

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An application using this option should enable the ability to receive
the association change notification. This is the only mechanism by
which an application is informed about the closing of an association.
After an association is closed, the association identifier assigned
to it can be reused. An application should be aware of this to avoid
the possible problem of sending data to an incorrect peer endpoint.

8.1.9. Set Primary Address (SCTP_PRIMARY_ADDR)

This option requests that the local SCTP stack uses the enclosed peer
address as the association's primary. The enclosed address must be
one of the association peer's addresses.

The following structure is used to make a set peer primary request:

struct sctp_setprim {
sctp_assoc_t ssp_assoc_id;
struct sockaddr_storage ssp_addr;
};

ssp_assoc_id: This parameter is ignored for one-to-one style
sockets. For one-to-many style sockets, it identifies the
association for this request. Note that the special sctp_assoc_t
SCTP_{FUTURE|ALL|CURRENT}_ASSOC are not allowed.

ssp_addr: This parameter is the address to set as primary. No
wildcard address is allowed.

8.1.10. Set Adaptation Layer Indicator (SCTP_ADAPTATION_LAYER)

This option requests that the local endpoint set the specified
Adaptation Layer Indication parameter for all future INIT and
INIT-ACK exchanges.

The following structure is used to access and modify this parameter:

struct sctp_setadaptation {
uint32_t ssb_adaptation_ind;
};

ssb_adaptation_ind: The adaptation layer indicator that will be
included in any outgoing Adaptation Layer Indication parameter.

8.1.11. Enable/Disable Message Fragmentation (SCTP_DISABLE_FRAGMENTS)

This option is an on/off flag and is passed as an integer, where a
non-zero is on and a zero is off. If enabled, no SCTP message
fragmentation will be performed. The effect of enabling this option

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is that if a message being sent exceeds the current Path MTU (PMTU)
size, the message will not be sent and instead an error will be
indicated to the user. If this option is disabled (the default),
then a message exceeding the size of the PMTU will be fragmented and
reassembled by the peer.

8.1.12. Peer Address Parameters (SCTP_PEER_ADDR_PARAMS)

Applications can enable or disable heartbeats for any peer address of
an association, modify an address's heartbeat interval, force a
heartbeat to be sent immediately, and adjust the address's maximum
number of retransmissions sent before an address is considered
unreachable.

The following structure is used to access and modify an address's
parameters:

struct sctp_paddrparams {
sctp_assoc_t spp_assoc_id;
struct sockaddr_storage spp_address;
uint32_t spp_hbinterval;
uint16_t spp_pathmaxrxt;
uint32_t spp_pathmtu;
uint32_t spp_flags;
uint32_t spp_ipv6_flowlabel;
uint8_t spp_dscp;
};

spp_assoc_id: This parameter is ignored for one-to-one style
sockets. For one-to-many style sockets, the application may fill
in an association identifier or SCTP_FUTURE_ASSOC for this query.
It is an error to use SCTP_{CURRENT|ALL}_ASSOC in spp_assoc_id.

spp_address: This specifies which address is of interest. If a
wildcard address is provided, it applies to all current and future
paths.

spp_hbinterval: This contains the value of the heartbeat interval,
in milliseconds (HB.Interval in [RFC4960]). Note that unless the
spp_flags field is set to SPP_HB_ENABLE, the value of this field
is ignored. Note also that a value of zero indicates that the
current setting should be left unchanged. To set an actual value
of zero, the SPP_HB_TIME_IS_ZERO flag should be used. Even when
it is set to 0, it does not mean that SCTP will continuously send
out heartbeats, since the actual interval also includes the
current RTO and jitter (see Section 8.3 of [RFC4960]).

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spp_pathmaxrxt: This contains the maximum number of retransmissions
before this address shall be considered unreachable. Note that a
value of zero indicates that the current setting should be left
unchanged.

spp_pathmtu: This field contains the current Path MTU of the peer
address. It is the number of bytes available in an SCTP packet
for chunks. Providing a value of 0 does not change the current
setting. If a positive value is provided and SPP_PMTUD_DISABLE is
set in the spp_flags field, the given value is used as the Path
MTU. If SPP_PMTUD_ENABLE is set in the spp_flags field, the
spp_pathmtu field is ignored.

spp_flags: These flags are used to control various features on an
association. The flag field is a bitmask that may contain zero or
more of the following options:

SPP_HB_ENABLE: This field enables heartbeats on the specified
address.

SPP_HB_DISABLE: This field disables heartbeats on the specified
address. Note that SPP_HB_ENABLE and SPP_HB_DISABLE are
mutually exclusive; only one of these two should be specified.
Enabling both fields will yield undetermined results.

SPP_HB_DEMAND: This field requests that a user-initiated
heartbeat be made immediately. This must not be used in
conjunction with a wildcard address.

SPP_HB_TIME_IS_ZERO: This field specifies that the time for
heartbeat delay is to be set to 0 milliseconds.

SPP_PMTUD_ENABLE: This field will enable PMTU discovery on the
specified address.

SPP_PMTUD_DISABLE: This field will disable PMTU discovery on the
specified address. Note that if the address field is empty,
then all addresses on the association are affected. Note also
that SPP_PMTUD_ENABLE and SPP_PMTUD_DISABLE are mutually
exclusive. Enabling both fields will yield undetermined
results.

SPP_IPV6_FLOWLABEL: Setting this flag enables the setting of the
IPV6 flow label value. The value is contained in the
spp_ipv6_flowlabel field.

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Upon retrieval, this flag will be set to indicate that the
spp_ipv6_flowlabel field has a valid value returned. If a
specific destination address is set (in the spp_address field),
then the value returned is that of the address. If just an
association is specified (and no address), then the
association's default flow label is returned. If neither an
association nor a destination is specified, then the socket's
default flow label is returned. For non-IPv6 sockets, this
flag will be left cleared.

SPP_DSCP: Setting this flag enables the setting of the
Differentiated Services Code Point (DSCP) value associated with
either the association or a specific address. The value is
obtained in the spp_dscp field.

Upon retrieval, this flag will be set to indicate that the
spp_dscp field has a valid value returned. If a specific
destination address is set when called (in the spp_address
field), then that specific destination address's DSCP value is
returned. If just an association is specified, then the
association's default DSCP is returned. If neither an
association nor a destination is specified, then the socket's
default DSCP is returned.

spp_ipv6_flowlabel: This field is used in conjunction with the
SPP_IPV6_FLOWLABEL flag and contains the IPv6 flow label. The 20
least significant bits are used for the flow label. This setting
has precedence over any IPv6-layer setting.

spp_dscp: This field is used in conjunction with the SPP_DSCP flag
and contains the DSCP. The 6 most significant bits are used for
the DSCP. This setting has precedence over any IPv4- or IPv6-
layer setting.

Please note that changing the flow label or DSCP value will affect
all packets sent by the SCTP stack after setting these parameters.
The flow label might also be set via the sin6_flowinfo field of the
sockaddr_in6 structure.

8.1.13. Set Default Send Parameters (SCTP_DEFAULT_SEND_PARAM) -
DEPRECATED

Please note that this option is deprecated. SCTP_DEFAULT_SNDINFO
(Section 8.1.31) should be used instead.

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such an application to set the default sctp_sndrcvinfo structure.
The application that wishes to use this socket option simply passes
the sctp_sndrcvinfo structure (defined in Section 5.3.2) to this
call. The input parameters accepted by this call include
sinfo_stream, sinfo_flags, sinfo_ppid, sinfo_context, and
sinfo_timetolive. The sinfo_flags field is composed of a bitwise OR
of SCTP_UNORDERED, SCTP_EOF, and SCTP_SENDALL. The sinfo_assoc_id
field specifies the association to which to apply the parameters.
For a one-to-many style socket, any of the predefined constants are
also allowed in this field. The field is ignored for one-to-one
style sockets.

8.1.14. Set Notification and Ancillary Events (SCTP_EVENTS) -
DEPRECATED

This socket option is used to specify various notifications and
ancillary data the user wishes to receive. Please see Section 6.2.1
for a full description of this option and its usage. Note that this
option is considered deprecated and is present for backward
compatibility. New applications should use the SCTP_EVENT option.
See Section 6.2.2 for a full description of that option as well.

8.1.15. Set/Clear IPv4 Mapped Addresses (SCTP_I_WANT_MAPPED_V4_ADDR)

This socket option is a boolean flag that turns on or off the mapping
of IPv4 addresses. If this option is turned on, then IPv4 addresses
will be mapped to IPv6 representation. If this option is turned off,
then no mapping will be done of IPv4 addresses, and a user will
receive both PF_INET6 and PF_INET type addresses on the socket. See
[RFC3542] for more details on mapped IPv6 addresses.

If this socket option is used on a socket of type PF_INET, an error
is returned.

By default, this option is turned off and expects an integer to be
passed where a non-zero value turns on the option and a zero value
turns off the option.

8.1.16. Get or Set the Maximum Fragmentation Size (SCTP_MAXSEG)

This option will get or set the maximum size to put in any outgoing
SCTP DATA chunk. If a message is larger than this maximum size, it
will be fragmented by SCTP into the specified size. Note that the
underlying SCTP implementation may fragment into smaller sized chunks
when the PMTU of the underlying association is smaller than the value
set by the user. The default value for this option is '0', which
indicates that the user is not limiting fragmentation and only the
PMTU will affect SCTP's choice of DATA chunk size. Note also that

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values set larger than the maximum size of an IP datagram will
effectively let SCTP control fragmentation (i.e., the same as setting
this option to 0).

The following structure is used to access and modify this parameter:

struct sctp_assoc_value {
sctp_assoc_t assoc_id;
uint32_t assoc_value;
};

assoc_id: This parameter is ignored for one-to-one style sockets.
For one-to-many style sockets, this parameter indicates upon which
association the user is performing an action. It is an error to
use SCTP_{CURRENT|ALL}_ASSOC in assoc_id.

assoc_value: This parameter specifies the maximum size in bytes.

8.1.17. Get or Set the List of Supported HMAC Identifiers
(SCTP_HMAC_IDENT)

This option gets or sets the list of Hashed Message Authentication
Code (HMAC) algorithms that the local endpoint requires the peer
to use.

The following structure is used to get or set these identifiers:

struct sctp_hmacalgo {
uint32_t shmac_number_of_idents;
uint16_t shmac_idents[];
};

shmac_number_of_idents: This field gives the number of elements
present in the array shmac_idents.

shmac_idents: This parameter contains an array of HMAC identifiers
that the local endpoint is requesting the peer to use, in priority
order. The following identifiers are valid:

* SCTP_AUTH_HMAC_ID_SHA1

* SCTP_AUTH_HMAC_ID_SHA256

Note that the list supplied must include SCTP_AUTH_HMAC_ID_SHA1 and
may include any of the other values in its preferred order (lowest
list position has the highest preference in algorithm selection).

quot;A list of mappings from IPv6 addresses to
link-layer addresses.

Entries in this list in the intended configuration are
used as static entries in the Neighbor Cache.

In the operational state, this list represents the
Neighbor Cache.";
reference
"RFC 4861: Neighbor Discovery for IP version 6 (IPv6)";

leaf ip {
type inet:ipv6-address-no-zone;
description
"The IPv6 address of the neighbor node.";
}
leaf link-layer-address {
type yang:phys-address;
mandatory true;
description
"The link-layer address of the neighbor node.

In the operational state, if the neighbor's 'state' leaf
is 'incomplete', this leaf is not instantiated.";
}
leaf origin {
type neighbor-origin;
config false;
description
"The origin of this neighbor entry.";
}
leaf is-router {
type empty;
config false;
description
"Indicates that the neighbor node acts as a router.";
}

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leaf state {
type enumeration {
enum incomplete {
description
"Address resolution is in progress, and the
link-layer address of the neighbor has not yet been
determined.";
}
enum reachable {
description
"Roughly speaking, the neighbor is known to have been
reachable recently (within tens of seconds ago).";
}
enum stale {
description
"The neighbor is no longer known to be reachable, but
until traffic is sent to the neighbor no attempt
should be made to verify its reachability.";
}
enum delay {
description
"The neighbor is no longer known to be reachable, and
traffic has recently been sent to the neighbor.
Rather than probe the neighbor immediately, however,
delay sending probes for a short while in order to
give upper-layer protocols a chance to provide
reachability confirmation.";
}
enum probe {
description
"The neighbor is no longer known to be reachable, and
unicast Neighbor Solicitation probes are being sent
to verify reachability.";
}
}
config false;
description
"The Neighbor Unreachability Detection state of this
entry.";
reference
"RFC 4861: Neighbor Discovery for IP version 6 (IPv6)
Section 7.3.2";
}
}

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leaf dup-addr-detect-transmits {
type uint32;
default 1;
description
"The number of consecutive Neighbor Solicitation messages
sent while performing Duplicate Address Detection on a
tentative address. A value of zero indicates that
Duplicate Address Detection is not performed on
tentative addresses. A value of one indicates a single
transmission with no follow-up retransmissions.";
reference
"RFC 4862: IPv6 Stateless Address Autoconfiguration";
}
container autoconf {
description
"Parameters to control the autoconfiguration of IPv6
addresses, as described in RFC 4862.";
reference
"RFC 4862: IPv6 Stateless Address Autoconfiguration";

leaf create-global-addresses {
type boolean;
default true;
description
"If enabled, the host creates global addresses as
described in RFC 4862.";
reference
"RFC 4862: IPv6 Stateless Address Autoconfiguration
Section 5.5";
}
leaf create-temporary-addresses {
if-feature ipv6-privacy-autoconf;
type boolean;
default false;
description
"If enabled, the host creates temporary addresses as
described in RFC 4941.";
reference
"RFC 4941: Privacy Extensions for Stateless Address
Autoconfiguration in IPv6";
}

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leaf temporary-valid-lifetime {
if-feature ipv6-privacy-autoconf;
type uint32;
units "seconds";
default 604800;
description
"The time period during which the temporary address
is valid.";
reference
"RFC 4941: Privacy Extensions for Stateless Address
Autoconfiguration in IPv6
- TEMP_VALID_LIFETIME";
}
leaf temporary-preferred-lifetime {
if-feature ipv6-privacy-autoconf;
type uint32;
units "seconds";
default 86400;
description
"The time period during which the temporary address is
preferred.";
reference
"RFC 4941: Privacy Extensions for Stateless Address
Autoconfiguration in IPv6
- TEMP_PREFERRED_LIFETIME";
}
}
}
}

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/*
* Legacy operational state data nodes
*/

augment "/if:interfaces-state/if:interface" {
status deprecated;
description
"Data nodes for the operational state of IP on interfaces.";

container ipv4 {
presence
"Present if IPv4 is enabled on this interface";
config false;
status deprecated;
description
"Interface-specific parameters for the IPv4 address family.";

leaf forwarding {
type boolean;
status deprecated;
description
"Indicates whether IPv4 packet forwarding is enabled or
disabled on this interface.";
}
leaf mtu {
type uint16 {
range "68..max";
}
units "octets";
status deprecated;
description
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Note also that the lack of SCTP_AUTH_HMAC_ID_SHA1, or the inclusion
of an unknown HMAC identifier (including optional identifiers unknown
to the implementation), will cause the set option to fail and return
an error.

8.1.18. Get or Set the Active Shared Key (SCTP_AUTH_ACTIVE_KEY)

This option will get or set the active shared key to be used to build
the association shared key.

The following structure is used to access and modify these
parameters:

struct sctp_authkeyid {
sctp_assoc_t scact_assoc_id;
uint16_t scact_keynumber;
};

scact_assoc_id: This parameter sets the active key of the specified
association. The special SCTP_{FUTURE|CURRENT|ALL}_ASSOC can be
used. For one-to-one style sockets, this parameter is ignored.
Note, however, that this option will set the active key on the
association if the socket is connected; otherwise, this option
will set the default active key for the endpoint.

scact_keynumber: This parameter is the shared key identifier that
the application is requesting to become the active shared key to
be used for sending authenticated chunks. The key identifier must
correspond to an existing shared key. Note that shared key
identifier '0' defaults to a null key.

When used with setsockopt(), the SCTP implementation must use the
indicated shared key identifier for all messages being given to an
SCTP implementation via a send call after the setsockopt() call,
until changed again. Therefore, the SCTP implementation must not
bundle user messages that should be authenticated using different
shared key identifiers.

Initially, the key with key identifier 0 is the active key.

8.1.19. Get or Set Delayed SACK Timer (SCTP_DELAYED_SACK)

This option will affect the way delayed SACKs are performed. This
option allows the application to get or set the delayed SACK time, in
milliseconds. It also allows changing the delayed SACK frequency.
Changing the frequency to 1 disables the delayed SACK algorithm.
Note that if sack_delay or sack_freq is 0 when setting this option,
the current values will remain unchanged.

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The following structure is used to access and modify these
parameters:

struct sctp_sack_info {
sctp_assoc_t sack_assoc_id;
uint32_t sack_delay;
uint32_t sack_freq;
};

sack_assoc_id: This parameter is ignored for one-to-one style
sockets. For one-to-many style sockets, this parameter indicates
upon which association the user is performing an action. The
special SCTP_{FUTURE|CURRENT|ALL}_ASSOC can also be used.

sack_delay: This parameter contains the number of milliseconds the
user is requesting that the delayed SACK timer be set to. Note
that this value is defined in [RFC4960] to be between 200 and 500
milliseconds.

sack_freq: This parameter contains the number of packets that must
be received before a SACK is sent without waiting for the delay
timer to expire. The default value is 2; setting this value to 1
will disable the delayed SACK algorithm.

8.1.20. Get or Set Fragmented Interleave (SCTP_FRAGMENT_INTERLEAVE)

Fragmented interleave controls how the presentation of messages
occurs for the message receiver. There are three levels of fragment
interleave defined. Two of the levels affect one-to-one style
sockets, while one-to-many style sockets are affected by all three
levels.

This option takes an integer value. It can be set to a value of 0,
1, or 2. Attempting to set this level to other values will return an
error.

Setting the three levels provides the following receiver
interactions:

level 0: Prevents the interleaving of any messages. This means that
when a partial delivery begins, no other messages will be received
except the message being partially delivered. If another message
arrives on a different stream (or association) that could be
delivered, it will be blocked waiting for the user to read all of
the partially delivered message.

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level 1: Allows interleaving of messages that are from different
associations. For one-to-one style sockets, level 0 and level 1
thus have the same meaning, since a one-to-one style socket always
receives messages from the same association. Note that setting a
one-to-many style socket to this level may cause multiple partial
deliveries from different associations, but for any given
association, only one message will be delivered until all parts of
a message have been delivered. This means that one large message,
being read with an association identifier of "X", will block other
messages from association "X" from being delivered.

level 2: Allows complete interleaving of messages. This level
requires that the sender not only carefully observe the peer
association identifier (or address) but also pay careful attention
to the stream number. With this option enabled, a partially
delivered message may begin being delivered for association "X"
stream "Y", and the next subsequent receive may return a message
from association "X" stream "Z". Note that no other messages
would be delivered for association "X" stream "Y" until all of
stream "Y"'s partially delivered message was read. Note that this
option also affects one-to-one style sockets. Also note that for
one-to-many style sockets, not only another stream's message from
the same association may be delivered upon the next receive, but
some other association's message may also be delivered upon the
next receive.

An implementation should default one-to-many style sockets to level
1, because otherwise, it is possible that a peer could begin sending
a partial message and thus block all other peers from sending data.
However, a setting of level 2 requires that the application not only
be aware of the association (via the association identifier or peer's
address) but also the stream number. The stream number is not
present unless the user has subscribed to the sctp_data_io_event (see
Section 6.2), which is deprecated, or has enabled the
SCTP_RECVRCVINFO socket option (see Section 8.1.29). This is also
why we recommend that one-to-one style sockets be defaulted to level
0 (level 1 for one-to-one style sockets has no effect). Note that an
implementation should return an error if an application attempts to
set the level to 2 and has not subscribed to the sctp_data_io_event
event, which is deprecated, or has enabled the SCTP_RECVRCVINFO
socket option.

For applications that have subscribed to events, those events appear
in the normal socket buffer data stream. This means that unless the
user has set the fragmentation interleave level to 0, notifications
may also be interleaved with partially delivered messages.

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8.1.21. Set or Get the SCTP Partial Delivery Point
(SCTP_PARTIAL_DELIVERY_POINT)

This option will set or get the SCTP partial delivery point. This
point is the size of a message where the partial delivery API will be
invoked to help free up rwnd space for the peer. Setting this to a
lower value will cause partial deliveries to happen more often. This
option expects an integer that sets or gets the partial delivery
point in bytes. Note also that the call will fail if the user
attempts to set this value larger than the socket receive buffer
size.

Note that any single message having a length smaller than or equal to
the SCTP partial delivery point will be delivered in a single read
call as long as the user-provided buffer is large enough to hold the
message.

8.1.22. Set or Get the Use of Extended Receive Info
(SCTP_USE_EXT_RCVINFO) - DEPRECATED

This option will enable or disable the use of the extended version of
the sctp_sndrcvinfo structure. If this option is disabled, then the
normal sctp_sndrcvinfo structure is returned in all receive message
calls. If this option is enabled, then the sctp_extrcvinfo structure
is returned in all receive message calls. The default is off.

Note that the sctp_extrcvinfo structure is never used in any send
call.

This option is present for compatibility with older applications and
is deprecated. Future applications should use SCTP_NXTINFO to
retrieve this same information via ancillary data.

8.1.23. Set or Get the Auto ASCONF Flag (SCTP_AUTO_ASCONF)

This option will enable or disable the use of the automatic
generation of ASCONF chunks to add and delete addresses to an
existing association. Note that this option has two caveats, namely
a) it only affects sockets that are bound to all addresses available
to the SCTP stack, and b) the system administrator may have an
overriding control that turns the ASCONF feature off no matter what
setting the socket option may have.

This option expects an integer boolean flag, where a non-zero value
turns on the option, and a zero value turns off the option.

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8.1.24. Set or Get the Maximum Burst (SCTP_MAX_BURST)

This option will allow a user to change the maximum burst of packets
that can be emitted by this association. Note that the default value
is 4, and some implementations may restrict this setting so that it
can only be lowered to positive values.

To set or get this option, the user fills in the following structure:

struct sctp_assoc_value {
sctp_assoc_t assoc_id;
uint32_t assoc_value;
};

assoc_id: This parameter is ignored for one-to-one style sockets.
For one-to-many style sockets, this parameter indicates upon which
association the user is performing an action. The special
SCTP_{FUTURE|CURRENT|ALL}_ASSOC can also be used.

assoc_value: This parameter contains the maximum burst. Setting the
value to 0 disables burst mitigation.

8.1.25. Set or Get the Default Context (SCTP_CONTEXT)

The context field in the sctp_sndrcvinfo structure is normally only
used when a failed message is retrieved holding the value that was
sent down on the actual send call. This option allows the setting,
on an association basis, of a default context that will be received
on reading messages from the peer. This is especially helpful for an
application when using one-to-many style sockets to keep some
reference to an internal state machine that is processing messages on
the association. Note that the setting of this value only affects
received messages from the peer and does not affect the value that is
saved with outbound messages.

To set or get this option, the user fills in the following structure:

struct sctp_assoc_value {
sctp_assoc_t assoc_id;
uint32_t assoc_value;
};

assoc_id: This parameter is ignored for one-to-one style sockets.
For one-to-many style sockets, this parameter indicates upon which
association the user is performing an action. The special
SCTP_{FUTURE|CURRENT|ALL}_ASSOC can also be used.

assoc_value: This parameter contains the context.

Stewart, et al. Informational [Page 78]
quot;The size, in octets, of the largest IPv4 packet that the
interface will send and receive.";
reference
"RFC 791: Internet Protocol";
}
list address {
key "ip";
status deprecated;
description
"The list of IPv4 addresses on the interface.";

leaf ip {
type inet:ipv4-address-no-zone;
status deprecated;
description
"The IPv4 address on the interface.";
}

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choice subnet {
status deprecated;
description
"The subnet can be specified as a prefix length or,
if the server supports non-contiguous netmasks, as
a netmask.";
leaf prefix-length {
type uint8 {
range "0..32";
}
status deprecated;
description
"The length of the subnet prefix.";
}
leaf netmask {
if-feature ipv4-non-contiguous-netmasks;
type yang:dotted-quad;
status deprecated;
description
"The subnet specified as a netmask.";
}
}
leaf origin {
type ip-address-origin;
status deprecated;
description
"The origin of this address.";
}
}
list neighbor {
key "ip";
status deprecated;
description
"A list of mappings from IPv4 addresses to
link-layer addresses.

This list represents the ARP Cache.";
reference
"RFC 826: An Ethernet Address Resolution Protocol";

leaf ip {
type inet:ipv4-address-no-zone;
status deprecated;
description
"The IPv4 address of the neighbor node.";
}

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leaf link-layer-address {
type yang:phys-address;
status deprecated;
description
"The link-layer address of the neighbor node.";
}
leaf origin {
type neighbor-origin;
status deprecated;
description
"The origin of this neighbor entry.";
}
}
}

container ipv6 {
presence
"Present if IPv6 is enabled on this interface";
config false;
status deprecated;
description
"Parameters for the IPv6 address family.";

leaf forwarding {
type boolean;
default false;
status deprecated;
description
"Indicates whether IPv6 packet forwarding is enabled or
disabled on this interface.";
reference
"RFC 4861: Neighbor Discovery for IP version 6 (IPv6)
Section 6.2.1, IsRouter";
}
leaf mtu {
type uint32 {
range "1280..max";
}
units "octets";
status deprecated;
description
"The size, in octets, of the largest IPv6 packet that the
interface will send and receive.";
reference
"RFC 8200: Internet Protocol, Version 6 (IPv6)
Specification
Section 5";
}

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list address {
key "ip";
status deprecated;
description
"The list of IPv6 addresses on the interface.";

leaf ip {
type inet:ipv6-address-no-zone;
status deprecated;
description
"The IPv6 address on the interface.";
}
leaf prefix-length {
type uint8 {
range "0..128";
}
mandatory true;
status deprecated;
description
"The length of the subnet prefix.";
}
leaf origin {
type ip-address-origin;
status deprecated;
description
"The origin of this address.";
}
leaf status {
type enumeration {
enum preferred {
description
"This is a valid address that can appear as the
destination or source address of a packet.";
}
enum deprecated {
description
"This is a valid but deprecated address that should
no longer be used as a source address in new
communications, but packets addressed to such an
address are processed as expected.";
}
enum invalid {
description
"This isn't a valid address, and it shouldn't appear
as the destination or source address of a packet.";
}

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enum inaccessible {
description
"The address is not accessible because the interface
to which this address is assigned is not
operational.";
}
enum unknown {
description
"The status cannot be determined for some reason.";
}
enum tentative {
description
"The uniqueness of the address on the link is being
verified. Addresses in this state should not be
used for general communication and should only be
used to determine the uniqueness of the address.";
}
enum duplicate {
description
"The address has been determined to be non-unique on
the link and so must not be used.";
}
enum optimistic {
description
"The address is available for use, subject to
restrictions, while its uniqueness on a link is
being verified.";
}
}
status deprecated;
description
"The status of an address. Most of the states correspond
to states from the IPv6 Stateless Address
Autoconfiguration protocol.";
reference
"RFC 4293: Management Information Base for the
Internet Protocol (IP)
- IpAddressStatusTC
RFC 4862: IPv6 Stateless Address Autoconfiguration";
}
}

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list neighbor {
key "ip";
status deprecated;
description
"A list of mappings from IPv6 addresses to
link-layer addresses.

This list represents the Neighbor Cache.";
reference
"RFC 4861: Neighbor Discovery for IP version 6 (IPv6)";

leaf ip {
type inet:ipv6-address-no-zone;
status deprecated;
description
"The IPv6 address of the neighbor node.";
}
leaf link-layer-address {
type yang:phys-address;
status deprecated;
description
"The link-layer address of the neighbor node.";
}
leaf origin {
type neighbor-origin;
status deprecated;
description
"The origin of this neighbor entry.";
}
leaf is-router {
type empty;
status deprecated;
description
"Indicates that the neighbor node acts as a router.";
}
leaf state {
type enumeration {
enum incomplete {
description
"Address resolution is in progress, and the
link-layer address of the neighbor has not yet been
determined.";
}
enum reachable {
description
"Roughly speaking, the neighbor is known to have been
reachable recently (within tens of seconds ago).";
}

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enum stale {
description
"The neighbor is no longer known to be reachable, but
until traffic is sent to the neighbor no attempt
should be made to verify its reachability.";
}
enum delay {
description
"The neighbor is no longer known to be reachable, and
traffic has recently been sent to the neighbor.
Rather than probe the neighbor immediately, however,
delay sending probes for a short while in order to
give upper-layer protocols a chance to provide
reachability confirmation.";
}
enum probe {
description
"The neighbor is no longer known to be reachable, and
unicast Neighbor Solicitation probes are being sent
to verify reachability.";
}
}
status deprecated;
description
"The Neighbor Unreachability Detection state of this
entry.";
reference
"RFC 4861: Neighbor Discovery for IP version 6 (IPv6)
Section 7.3.2";
}
}
}
}
}
<CODE ENDS>

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5. IANA Considerations

This document registers a URI in the "IETF XML Registry" [RFC3688].
Following the format in RFC 3688, the following registration has been
made.

URI: urn:ietf:params:xml:ns:yang:ietf-ip
Registrant Contact: The NETMOD WG of the IETF.
XML: N/A; the requested URI is an XML namespace.

This document registers a YANG module in the "YANG Module Names"
registry [RFC6020].

Name: ietf-ip
Namespace: urn:ietf:params:xml:ns:yang:ietf-ip
Prefix: ip
Reference: RFC 8344

6. Security Considerations

The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such
as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer
is the secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer
is HTTPS, and the mandatory-to-implement secure transport is TLS
[RFC5246].

The NETCONF access control model [RFC8341] provides the means to
restrict access for particular NETCONF or RESTCONF users to a
preconfigured subset of all available NETCONF or RESTCONF protocol
operations and content.

There are a number of data nodes defined in this YANG module that are
writable/creatable/deletable (i.e., config true, which is the
default). These data nodes may be considered sensitive or vulnerable
in some network environments. Write operations (e.g., edit-config)
to these data nodes without proper protection can have a negative
effect on network operations. These are the subtrees and data nodes
and their sensitivity/vulnerability:

ipv4/enabled and ipv6/enabled: These leafs are used to enable or
disable IPv4 and IPv6 on a specific interface. By enabling a
protocol on an interface, an attacker might be able to create an
unsecured path into a node (or through it if routing is also
enabled). By disabling a protocol on an interface, an attacker

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RFC 8344 YANG IP Management March 2018

RFC 6458 SCTP Sockets API December 2011

8.1.26. Enable or Disable Explicit EOR Marking (SCTP_EXPLICIT_EOR)

This boolean flag is used to enable or disable explicit end of record
(EOR) marking. When this option is enabled, a user may make multiple
send system calls to send a record and must indicate that they are
finished sending a particular record by including the SCTP_EOR flag.
If this boolean flag is disabled, then each individual send system
call is considered to have an SCTP_EOR indicator set on it implicitly
without the user having to explicitly add this flag. The default
is off.

This option expects an integer boolean flag, where a non-zero value
turns on the option, and a zero value turns off the option.

8.1.27. Enable SCTP Port Reusage (SCTP_REUSE_PORT)

This option only supports one-to-one style SCTP sockets. If used on
a one-to-many style SCTP socket, an error is indicated.

This option expects an integer boolean flag, where a non-zero value
turns on the option, and a zero value turns off the option.

This socket option must not be used after calling bind() or
sctp_bindx() for a one-to-one style SCTP socket. If using bind() or
sctp_bindx() on a socket with the SCTP_REUSE_PORT option, all other
SCTP sockets bound to the same port must have set the SCTP_REUSE_PORT
option. Calling bind() or sctp_bindx() for a socket without having
set the SCTP_REUSE_PORT option will fail if there are other sockets
bound to the same port. At most one socket being bound to the same
port may be listening.

It should be noted that the behavior of the socket-level socket
option to reuse ports and/or addresses for SCTP sockets is
unspecified.

8.1.28. Set Notification Event (SCTP_EVENT)

This socket option is used to set a specific notification option.
Please see Section 6.2.2 for a full description of this option and
its usage.

8.1.29. Enable or Disable the Delivery of SCTP_RCVINFO as Ancillary
Data (SCTP_RECVRCVINFO)

Setting this option specifies that SCTP_RCVINFO (defined in
Section 5.3.5) is returned as ancillary data by recvmsg().

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RFC 6458 SCTP Sockets API December 2011

This option expects an integer boolean flag, where a non-zero value
turns on the option, and a zero value turns off the option.

8.1.30. Enable or Disable the Delivery of SCTP_NXTINFO as Ancillary
Data (SCTP_RECVNXTINFO)

Setting this option specifies that SCTP_NXTINFO (defined in
Section 5.3.6) is returned as ancillary data by recvmsg().

This option expects an integer boolean flag, where a non-zero value
turns on the option, and a zero value turns off the option.

8.1.31. Set Default Send Parameters (SCTP_DEFAULT_SNDINFO)

Applications that wish to use the sendto() system call may wish to
specify a default set of parameters that would normally be supplied
through the inclusion of ancillary data. This socket option allows
such an application to set the default sctp_sndinfo structure. The
application that wishes to use this socket option simply passes the
sctp_sndinfo structure (defined in Section 5.3.4) to this call. The
input parameters accepted by this call include snd_sid, snd_flags,
snd_ppid, and snd_context. The snd_flags parameter is composed of a
bitwise OR of SCTP_UNORDERED, SCTP_EOF, and SCTP_SENDALL. The
snd_assoc_id field specifies the association to which to apply the
parameters. For a one-to-many style socket, any of the predefined
constants are also allowed in this field. The field is ignored for
one-to-one style sockets.

8.1.32. Set Default PR-SCTP Parameters (SCTP_DEFAULT_PRINFO)

This option sets and gets the default parameters for PR-SCTP. They
can be overwritten by specific information provided in send calls.

The following structure is used to access and modify these
parameters:

struct sctp_default_prinfo {
uint16_t pr_policy;
uint32_t pr_value;
sctp_assoc_t pr_assoc_id;
};

pr_policy: This field is the same as that described in
Section 5.3.7.

pr_value: This field is the same as that described in Section 5.3.7.

Stewart, et al. Informational [Page 80]
RFC 6458 SCTP Sockets API December 2011

pr_assoc_id: This field is ignored for one-to-one style sockets.
For one-to-many style sockets, pr_assoc_id can be a particular
association identifier or SCTP_{FUTURE|CURRENT|ALL}_ASSOC.

8.2. Read-Only Options

The options defined in this subsection are read-only. Using this
option in a setsockopt() call will result in an error indicating
EOPNOTSUPP.

8.2.1. Association Status (SCTP_STATUS)

Applications can retrieve current status information about an
association, including association state, peer receiver window size,
number of unacknowledged DATA chunks, and number of DATA chunks
pending receipt. This information is read-only.

The following structure is used to access this information:

struct sctp_status {
sctp_assoc_t sstat_assoc_id;
int32_t sstat_state;
uint32_t sstat_rwnd;
uint16_t sstat_unackdata;
uint16_t sstat_penddata;
uint16_t sstat_instrms;
uint16_t sstat_outstrms;
uint32_t sstat_fragmentation_point;
struct sctp_paddrinfo sstat_primary;
};

sstat_assoc_id: This parameter is ignored for one-to-one style
sockets. For one-to-many style sockets, it holds the identifier
for the association. All notifications for a given association
have the same association identifier. The special SCTP_{FUTURE|
CURRENT|ALL}_ASSOC cannot be used.

sstat_state: This contains the association's current state, i.e.,
one of the following values:

* SCTP_CLOSED

* SCTP_BOUND

* SCTP_LISTEN

* SCTP_COOKIE_WAIT

Stewart, et al. Informational [Page 81]
RFC 6458 SCTP Sockets API December 2011

* SCTP_COOKIE_ECHOED

* SCTP_ESTABLISHED

* SCTP_SHUTDOWN_PENDING

* SCTP_SHUTDOWN_SENT

* SCTP_SHUTDOWN_RECEIVED

* SCTP_SHUTDOWN_ACK_SENT

sstat_rwnd: This contains the association peer's current receiver
window size.

sstat_unackdata: This is the number of unacknowledged DATA chunks.

sstat_penddata: This is the number of DATA chunks pending receipt.

sstat_instrms: This is the number of streams that the peer will be
using outbound.

sstat_outstrms: This is the number of outbound streams that the
endpoint is allowed to use.

sstat_fragmentation_point: This is the size at which SCTP
fragmentation will occur.

sstat_primary: This is information on the current primary peer
address.

To access these status values, the application calls getsockopt()
with the option name SCTP_STATUS.

8.2.2. Peer Address Information (SCTP_GET_PEER_ADDR_INFO)

Applications can retrieve information about a specific peer address
of an association, including its reachability state, congestion
window, and retransmission timer values. This information is
read-only.

The following structure is used to access this information:

struct sctp_paddrinfo {
sctp_assoc_t spinfo_assoc_id;
struct sockaddr_storage spinfo_address;
int32_t spinfo_state;
uint32_t spinfo_cwnd;

Stewart, et al. Informational [Page 82]
RFC 6458 SCTP Sockets API December 2011

uint32_t spinfo_srtt;
uint32_t spinfo_rto;
uint32_t spinfo_mtu;
};

spinfo_assoc_id: This parameter is ignored for one-to-one style
sockets.

For one-to-many style sockets, this field may be filled by the
application, and if so, this field will have priority in looking
up the association instead of using the address specified in
spinfo_address. Note that if the address does not belong to the
association specified, then this call will fail. If the
application does not fill in the spinfo_assoc_id, then the address
will be used to look up the association, and on return, this field
will have the valid association identifier. In other words, this
call can be used to translate an address into an association
identifier. Note that the predefined constants are not allowed
for this option.

spinfo_address: This is filled by the application and contains the
peer address of interest.

spinfo_state: This contains the peer address's state:

SCTP_UNCONFIRMED: This is the initial state of a peer address.

SCTP_ACTIVE: This state is entered the first time after path
verification. It can also be entered if the state is
SCTP_INACTIVE and the path supervision detects that the peer
address is reachable again.

SCTP_INACTIVE: This state is entered whenever a path failure is
detected.

spinfo_cwnd: This contains the peer address's current congestion
window.

spinfo_srtt: This contains the peer address's current smoothed
round-trip time calculation in milliseconds.

spinfo_rto: This contains the peer address's current retransmission
timeout value in milliseconds.

spinfo_mtu: This is the current Path MTU of the peer address. It is
the number of bytes available in an SCTP packet for chunks.

Stewart, et al. Informational [Page 83]
RFC 6458 SCTP Sockets API December 2011

8.2.3. Get the List of Chunks the Peer Requires to Be Authenticated
(SCTP_PEER_AUTH_CHUNKS)

This option gets a list of chunk types (see [RFC4960]) for a
specified association that the peer requires to be received
authenticated only.

The following structure is used to access these parameters:

struct sctp_authchunks {
sctp_assoc_t gauth_assoc_id;
uint32_t gauth_number_of_chunks
uint8_t gauth_chunks[];
};

gauth_assoc_id: This parameter indicates for which association the
user is requesting the list of peer-authenticated chunks. For
one-to-one style sockets, this parameter is ignored. Note that
the predefined constants are not allowed with this option.

gauth_number_of_chunks: This parameter gives the number of elements
in the array gauth_chunks.

gauth_chunks: This parameter contains an array of chunk types that
the peer is requesting to be authenticated. If the passed-in
buffer size is not large enough to hold the list of chunk types,
ENOBUFS is returned.

8.2.4. Get the List of Chunks the Local Endpoint Requires to Be
Authenticated (SCTP_LOCAL_AUTH_CHUNKS)

This option gets a list of chunk types (see [RFC4960]) for a
specified association that the local endpoint requires to be received
authenticated only.

The following structure is used to access these parameters:

struct sctp_authchunks {
sctp_assoc_t gauth_assoc_id;
uint32_t gauth_number_of_chunks;
uint8_t gauth_chunks[];
};

gauth_assoc_id: This parameter is ignored for one-to-one style
sockets. For one-to-many style sockets, the application may fill
in an association identifier or SCTP_FUTURE_ASSOC. It is an error
to use SCTP_{CURRENT|ALL}_ASSOC in gauth_assoc_id.

Stewart, et al. Informational [Page 84]
RFC 6458 SCTP Sockets API December 2011

gauth_number_of_chunks: This parameter gives the number of elements
in the array gauth_chunks.

gauth_chunks: This parameter contains an array of chunk types that
the local endpoint is requesting to be authenticated. If the
passed-in buffer is not large enough to hold the list of chunk
types, ENOBUFS is returned.

8.2.5. Get the Current Number of Associations (SCTP_GET_ASSOC_NUMBER)

This option gets the current number of associations that are attached
to a one-to-many style socket. The option value is an uint32_t.
Note that this number is only a snapshot. This means that the number
of associations may have changed when the caller gets back the option
result.

For a one-to-one style socket, this socket option results in an
error.

8.2.6. Get the Current Identifiers of Associations
(SCTP_GET_ASSOC_ID_LIST)

This option gets the current list of SCTP association identifiers of
the SCTP associations handled by a one-to-many style socket.

The option value has the structure

struct sctp_assoc_ids {
uint32_t gaids_number_of_ids;
sctp_assoc_t gaids_assoc_id[];
};

The caller must provide a large enough buffer to hold all association
identifiers. If the buffer is too small, an error must be returned.
The user can use the SCTP_GET_ASSOC_NUMBER socket option to get an
idea of how large the buffer has to be. gaids_number_of_ids gives
the number of elements in the array gaids_assoc_id. Note also that
some or all of sctp_assoc_t returned in the array may become invalid
by the time the caller gets back the result.

For a one-to-one style socket, this socket option results in an
error.

8.3. Write-Only Options

The options defined in this subsection are write-only. Using this
option in a getsockopt() or sctp_opt_info() call will result in an
error indicating EOPNOTSUPP.

might be able to force packets to be routed through some other
interface or deny access to some or all of the network via that
protocol.

ipv4/address and ipv6/address: These lists specify the configured IP
addresses on an interface. By modifying this information, an
attacker can cause a node to either ignore messages destined to it
or accept (at least at the IP layer) messages it would otherwise
ignore. The use of filtering or security associations may reduce
the potential damage in the latter case.

ipv4/forwarding and ipv6/forwarding: These leafs allow a client to
enable or disable the forwarding functions on the entity. By
disabling the forwarding functions, an attacker would possibly be
able to deny service to users. By enabling the forwarding
functions, an attacker could open a conduit into an area. This
might result in the area providing transit for packets it
shouldn't, or it might allow the attacker access to the area,
bypassing security safeguards.

ipv6/autoconf: The leafs in this branch control the
autoconfiguration of IPv6 addresses and, in particular, whether or
not temporary addresses are used. By modifying the corresponding
leafs, an attacker might impact the addresses used by a node and
-- thus, indirectly -- the privacy of the users using the node.

ipv4/mtu and ipv6/mtu: Setting these leafs to very small values can
be used to slow down interfaces.

Bjorklund Standards Track [Page 28]
RFC 8344 YANG IP Management March 2018

7. References

7.1. Normative References

[RFC791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981,
<https://www.rfc-editor.org/info/rfc791>.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.

[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.

[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>.

[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>.

[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007,
<https://www.rfc-editor.org/info/rfc4941>.

[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>.

[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.

[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.

Bjorklund Standards Track [Page 29]
RFC 8344 YANG IP Management March 2018

[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/info/rfc6242>.

[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.

[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.

[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.

[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in
RFC 2119 Key Words", BCP 14, RFC 8174,
DOI 10.17487/RFC8174, May 2017,
<https://www.rfc-editor.org/info/rfc8174>.

[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.

[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.

[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>.

[RFC8343] Bjorklund, M., "A YANG Data Model for Interface
Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
<https://www.rfc-editor.org/info/rfc8343>.

[W3C.REC-xml-20081126]
Bray, T., Paoli, J., Sperberg-McQueen, M., Maler, E., and
F. Yergeau, "Extensible Markup Language (XML) 1.0
(Fifth Edition)", World Wide Web Consortium Recommendation
REC-xml-20081126, November 2008,
<https://www.w3.org/TR/2008/REC-xml-20081126>.

Bjorklund Standards Track [Page 30]
RFC 8344 YANG IP Management March 2018

7.2. Informative References

[RFC826] Plummer, D., "An Ethernet Address Resolution Protocol: Or
Converting Network Protocol Addresses to 48.bit Ethernet
Address for Transmission on Ethernet Hardware", STD 37,
RFC 826, DOI 10.17487/RFC0826, November 1982,
<https://www.rfc-editor.org/info/rfc826>.

[RFC4293] Routhier, S., Ed., "Management Information Base for the
Internet Protocol (IP)", RFC 4293, DOI 10.17487/RFC4293,
April 2006, <https://www.rfc-editor.org/info/rfc4293>.

[RFC7217] Gont, F., "A Method for Generating Semantically Opaque
Interface Identifiers with IPv6 Stateless Address
Autoconfiguration (SLAAC)", RFC 7217,
DOI 10.17487/RFC7217, April 2014,
<https://www.rfc-editor.org/info/rfc7217>.

[RFC8022] Lhotka, L. and A. Lindem, "A YANG Data Model for Routing
Management", RFC 8022, DOI 10.17487/RFC8022,
November 2016, <https://www.rfc-editor.org/info/rfc8022>.

[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.

Bjorklund Standards Track [Page 31]
RFC 8344 YANG IP Management March 2018

Appendix A. Example: NETCONF <get-config> Reply

This section gives an example of a reply to the NETCONF <get-config>
request for the running configuration datastore for a device that
implements the data model defined in this document.

The XML [W3C.REC-xml-20081126] snippets that follow in this section
and in Appendix B are provided as examples only.

<rpc-reply
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
message-id="101">
<data>
<interfaces
xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
<interface>
<name>eth0</name>
<typeStewart, et al. Informational [Page 85]
RFC 6458 SCTP Sockets API December 2011

8.3.1. Set Peer Primary Address (SCTP_SET_PEER_PRIMARY_ADDR)

This call requests that the peer mark the enclosed address as the
association primary (see [RFC5061]). The enclosed address must be
one of the association's locally bound addresses.

The following structure is used to make a set peer primary request:

struct sctp_setpeerprim {
sctp_assoc_t sspp_assoc_id;
struct sockaddr_storage sspp_addr;
};

sspp_assoc_id: This parameter is ignored for one-to-one style
sockets. For one-to-many style sockets, it identifies the
association for this request. Note that the predefined constants
are not allowed for this option.

sspp_addr: The address to set as primary.

8.3.2. Add a Chunk That Must Be Authenticated (SCTP_AUTH_CHUNK)

This set option adds a chunk type that the user is requesting to be
received only in an authenticated way. Changes to the list of chunks
will only affect future associations on the socket.

The following structure is used to add a chunk:

struct sctp_authchunk {
uint8_t sauth_chunk;
};

sauth_chunk: This parameter contains a chunk type that the user is
requesting to be authenticated.

The chunk types for INIT, INIT-ACK, SHUTDOWN-COMPLETE, and AUTH
chunks must not be used. If they are used, an error must be
returned. The usage of this option enables SCTP AUTH in cases where
it is not required by other means (for example, the use of dynamic
address reconfiguration).

8.3.3. Set a Shared Key (SCTP_AUTH_KEY)

This option will set a shared secret key that is used to build an
association shared key.

The following structure is used to access and modify these
parameters:

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struct sctp_authkey {
sctp_assoc_t sca_assoc_id;
uint16_t sca_keynumber;
uint16_t sca_keylength;
uint8_t sca_key[];
};

sca_assoc_id: This parameter indicates on what association the
shared key is being set. The special SCTP_{FUTURE|CURRENT|
ALL}_ASSOC can be used. For one-to-one style sockets, this
parameter is ignored. Note, however, that on one-to-one style
sockets, this option will set a key on the association if the
socket is connected; otherwise, this option will set a key on the
endpoint.

sca_keynumber: This parameter is the shared key identifier by which
the application will refer to this shared key. If a key of the
specified index already exists, then this new key will replace the
old existing key. Note that shared key identifier '0' defaults to
a null key.

sca_keylength: This parameter is the length of the array sca_key.

sca_key: This parameter contains an array of bytes that is to be
used by the endpoint (or association) as the shared secret key.
Note that if the length of this field is zero, a null key is set.

8.3.4. Deactivate a Shared Key (SCTP_AUTH_DEACTIVATE_KEY)

This set option indicates that the application will no longer send
user messages using the indicated key identifier.

struct sctp_authkeyid {
sctp_assoc_t scact_assoc_id;
uint16_t scact_keynumber;
};

scact_assoc_id: This parameter indicates from which association the
shared key identifier is being deleted. The special SCTP_{FUTURE|
CURRENT|ALL}_ASSOC can be used. For one-to-one style sockets,
this parameter is ignored. Note, however, that this option will
deactivate the key from the association if the socket is
connected; otherwise, this option will deactivate the key from the
endpoint.

Stewart, et al. Informational [Page 87]
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scact_keynumber: This parameter is the shared key identifier that
the application is requesting to be deactivated. The key
identifier must correspond to an existing shared key. Note that
if this parameter is zero, use of the null key identifier '0' is
deactivated on the endpoint and/or association.

The currently active key cannot be deactivated.

8.3.5. Delete a Shared Key (SCTP_AUTH_DELETE_KEY)

This set option will delete an SCTP association's shared secret key
that has been deactivated.

struct sctp_authkeyid {
sctp_assoc_t scact_assoc_id;
uint16_t scact_keynumber;
};

scact_assoc_id: This parameter indicates from which association the
shared key identifier is being deleted. The special SCTP_{FUTURE|
CURRENT|ALL}_ASSOC can be used. For one-to-one style sockets,
this parameter is ignored. Note, however, that this option will
delete the key from the association if the socket is connected;
otherwise, this option will delete the key from the endpoint.

scact_keynumber: This parameter is the shared key identifier that
the application is requesting to be deleted. The key identifier
must correspond to an existing shared key and must not be in use
for any packet being sent by the SCTP implementation. This means,
in particular, that it must be deactivated first. Note that if
this parameter is zero, use of the null key identifier '0' is
deleted from the endpoint and/or association.

Only deactivated keys that are no longer used by an association can
be deleted.

9. New Functions

Depending on the system, the following interface can be implemented
as a system call or library function.

9.1. sctp_bindx()

This function allows the user to bind a specific subset of addresses
or, if the SCTP extension described in [RFC5061] is supported, add or
delete specific addresses.

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The function prototype is

int sctp_bindx(int sd,
struct sockaddr *addrs,
int addrcnt,
int flags);

If sd is an IPv4 socket, the addresses passed must be IPv4 addresses.
If the sd is an IPv6 socket, the addresses passed can either be IPv4
or IPv6 addresses.

A single address may be specified as INADDR_ANY for an IPv4 address,
or as IN6ADDR_ANY_INIT or in6addr_any for an IPv6 address; see
Section 3.1.2 for this usage.

addrs is a pointer to an array of one or more socket addresses. Each
address is contained in its appropriate structure. For an IPv6
socket, an array of sockaddr_in6 is used. For an IPv4 socket, an
array of sockaddr_in is used. The caller specifies the number of
addresses in the array with addrcnt. Note that the wildcard
addresses cannot be used in combination with non-wildcard addresses
on a socket with this function; doing so will result in an error.

On success, sctp_bindx() returns 0. On failure, sctp_bindx() returns
-1 and sets errno to the appropriate error code.

For SCTP, the port given in each socket address must be the same, or
sctp_bindx() will fail, setting errno to EINVAL.

The flags parameter is formed from the bitwise OR of zero or more of
the following currently defined flags:

o SCTP_BINDX_ADD_ADDR

o SCTP_BINDX_REM_ADDR

SCTP_BINDX_ADD_ADDR directs SCTP to add the given addresses to the
socket (i.e., endpoint), and SCTP_BINDX_REM_ADDR directs SCTP to
remove the given addresses from the socket. The two flags are
mutually exclusive; if both are given, sctp_bindx() will fail with
EINVAL. A caller may not remove all addresses from a socket;
sctp_bindx() will reject such an attempt with EINVAL.

An application can use sctp_bindx(SCTP_BINDX_ADD_ADDR) to associate
additional addresses with an endpoint after calling bind(). Or, an
application can use sctp_bindx(SCTP_BINDX_REM_ADDR) to remove some
addresses with which a listening socket is associated, so that no new
association accepted will be associated with these addresses. If the

Stewart, et al. Informational [Page 89]
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endpoint supports dynamic address reconfiguration, an
SCTP_BINDX_REM_ADDR or SCTP_BINDX_ADD_ADDR may cause an endpoint to
send the appropriate message to its peers to change the peers'
address lists.

Adding and removing addresses from established associations is an
optional functionality. Implementations that do not support this
functionality should return -1 and set errno to EOPNOTSUPP.

sctp_bindx() can be called on an already bound socket or on an
unbound socket. If the socket is unbound and the first port number
in the addrs parameter is zero, the kernel will choose a port number.
All port numbers after the first one being 0 must also be zero. If
the first port number is not zero, the following port numbers must be
zero or have the same value as the first one. For an already bound
socket, all port numbers provided must be the bound one or 0.

sctp_bindx() is an atomic operation. Therefore, the binding will
either succeed on all addresses or fail on all addresses. If
multiple addresses are provided and the sctp_bindx() call fails,
there is no indication of which address is responsible for the
failure. The only way to identify the specific error indication is
to call sctp_bindx() sequentially with only one address per call.

9.2. sctp_peeloff()

After an association is established on a one-to-many style socket,
the application may wish to branch off the association into a
separate socket/file descriptor.

This is particularly desirable when, for instance, the application
wishes to have a number of sporadic message senders/receivers remain
under the original one-to-many style socket but branch off these
associations carrying high-volume data traffic into their own
separate socket descriptors.

The application uses the sctp_peeloff() call to branch off an
association into a separate socket. (Note that the semantics are
somewhat changed from the traditional one-to-one style accept()
call.) Note also that the new socket is a one-to-one style socket.
Thus, it will be confined to operations allowed for a one-to-one
style socket.

The function prototype is

int sctp_peeloff(int sd,
sctp_assoc_t assoc_id);

Stewart, et al. Informational [Page 90]
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and the arguments are

sd: The original one-to-many style socket descriptor returned from
the socket() system call (see Section 3.1.1).

assoc_id: The specified identifier of the association that is to be
branched off to a separate file descriptor. (Note that in a
traditional one-to-one style accept() call, this would be an out
parameter, but for the one-to-many style call, this is an in
parameter.)

The function returns a non-negative file descriptor representing the
branched-off association, or -1 if an error occurred. The variable
errno is then set appropriately.

9.3. sctp_getpaddrs()

sctp_getpaddrs() returns all peer addresses in an association.

The function prototype is

int sctp_getpaddrs(int sd,
sctp_assoc_t id,
struct sockaddr **addrs);

On return, addrs will point to a dynamically allocated array of
sockaddr structures of the appropriate type for the socket type. The
caller should use sctp_freepaddrs() to free the memory. Note that
the in/out parameter addrs must not be NULL.

If sd is an IPv4 socket, the addresses returned will be all IPv4
addresses. If sd is an IPv6 socket, the addresses returned can be a
mix of IPv4 or IPv6 addresses, with IPv4 addresses returned according
to the SCTP_I_WANT_MAPPED_V4_ADDR option setting.

For one-to-many style sockets, id specifies the association to query.
For one-to-one style sockets, id is ignored.

On success, sctp_getpaddrs() returns the number of peer addresses in
the association. If there is no association on this socket,
sctp_getpaddrs() returns 0, and the value of *addrs is undefined. If
an error occurs, sctp_getpaddrs() returns -1, and the value of *addrs
is undefined.

Stewart, et al. Informational [Page 91]
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9.4. sctp_freepaddrs()

sctp_freepaddrs() frees all resources allocated by sctp_getpaddrs().

The function prototype is

void sctp_freepaddrs(struct sockaddr *addrs);

and addrs is the array of peer addresses returned by
sctp_getpaddrs().

9.5. sctp_getladdrs()

sctp_getladdrs() returns all locally bound addresses on a socket.

The function prototype is

int sctp_getladdrs(int sd,
sctp_assoc_t id,
struct sockaddr **addrs);

On return, addrs will point to a dynamically allocated array of
sockaddr structures of the appropriate type for the socket type. The
caller should use sctp_freeladdrs() to free the memory. Note that
the in/out parameter addrs must not be NULL.

For one-to-many style sockets, id specifies the association to query.
For one-to-one style sockets, id is ignored.

If the id field is set to the value '0', then the locally bound
addresses are returned without regard to any particular association.

On success, sctp_getladdrs() returns the number of local addresses
bound to the socket. If the socket is unbound, sctp_getladdrs()
returns 0, and the value of *addrs is undefined. If an error occurs,
sctp_getladdrs() returns -1, and the value of *addrs is undefined.

Stewart, et al. Informational [Page 92]
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9.6. sctp_freeladdrs()

sctp_freeladdrs() frees all resources allocated by sctp_getladdrs().

The function prototype is

void sctp_freeladdrs(struct sockaddr *addrs);

and addrs is the array of local addresses returned by
sctp_getladdrs().

9.7. sctp_sendmsg() - DEPRECATED

This function is deprecated; sctp_sendv() (see Section 9.12) should
be used instead.

An implementation may provide a library function (or possibly system
call) to assist the user with the advanced features of SCTP.

The function prototype is

ssize_t sctp_sendmsg(int sd,
const void *msg,
size_t len,
const struct sockaddr *to,
socklen_t tolen,
uint32_t ppid,
uint32_t flags,
uint16_t stream_no,
uint32_t timetolive,
uint32_t context);

and the arguments are

sd: The socket descriptor.

msg: The message to be sent.

len: The length of the message.

to: The destination address of the message.

tolen: The length of the destination address.

ppid: The same as sinfo_ppid (see Section 5.3.2).

flags: The same as sinfo_flags (see Section 5.3.2).

Stewart, et al. Informational [Page 93]
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stream_no: The same as sinfo_stream (see Section 5.3.2).

timetolive: The same as sinfo_timetolive (see Section 5.3.2).

context: The same as sinfo_context (see Section 5.3.2).

The call returns the number of characters sent, or -1 if an error
occurred. The variable errno is then set appropriately.

Sending a message using sctp_sendmsg() is atomic (unless explicit EOR
marking is enabled on the socket specified by sd).

Using sctp_sendmsg() on a non-connected one-to-one style socket for
implicit connection setup may or may not work, depending on the SCTP
implementation.

9.8. sctp_recvmsg() - DEPRECATED

This function is deprecated; sctp_recvv() (see Section 9.13) should
be used instead.

An implementation may provide a library function (or possibly system
call) to assist the user with the advanced features of SCTP. Note
that in order for the sctp_sndrcvinfo structure to be filled in by
sctp_recvmsg(), the caller must enable the sctp_data_io_event with
the SCTP_EVENTS option. Note that the setting of the
SCTP_USE_EXT_RCVINFO will affect this function as well, causing the
sctp_sndrcvinfo information to be extended.

The function prototype is

ssize_t sctp_recvmsg(int sd,
void *msg,
size_t len,
struct sockaddr *from,
socklen_t *fromlen
struct sctp_sndrcvinfo *sinfo
int *msg_flags);

and the arguments are

sd: The socket descriptor.

msg: The message buffer to be filled.

len: The length of the message buffer.

Stewart, et al. Informational [Page 94]
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from: A pointer to an address to be filled with the address of the
sender of this message.

fromlen: An in/out parameter describing the from length.

sinfo: A pointer to an sctp_sndrcvinfo structure to be filled upon
receipt of the message.

msg_flags: A pointer to an integer to be filled with any message
flags (e.g., MSG_NOTIFICATION). Note that this field is an in-out
field. Options for the receive may also be passed into the value
(e.g., MSG_PEEK). On return from the call, the msg_flags value
will be different than what was sent in to the call. If
implemented via a recvmsg() call, the msg_flags parameter should
only contain the value of the flags from the recvmsg() call.

The call returns the number of bytes received, or -1 if an error
occurred. The variable errno is then set appropriately.

9.9. sctp_connectx()

An implementation may provide a library function (or possibly system
call) to assist the user with associating to an endpoint that is
multi-homed. Much like sctp_bindx(), this call allows a caller to
specify multiple addresses at which a peer can be reached. The way
the SCTP stack uses the list of addresses to set up the association
is implementation dependent. This function only specifies that the
stack will try to make use of all of the addresses in the list when
needed.

Note that the list of addresses passed in is only used for setting up
the association. It does not necessarily equal the set of addresses
the peer uses for the resulting association. If the caller wants to
find out the set of peer addresses, it must use sctp_getpaddrs() to
retrieve them after the association has been set up.

The function prototype is

int sctp_connectx(int sd,
struct sockaddr *addrs,
int addrcnt,
sctp_assoc_t *id);

and the arguments are

sd: The socket descriptor.

addrs: An array of addresses.

Stewart, et al. Informational [Page 95]
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addrcnt: The number of addresses in the array.

id: An output parameter that, if passed in as non-NULL, will return
the association identifier for the newly created association (if
successful).

The call returns 0 on success or -1 if an error occurred. The
variable errno is then set appropriately.

9.10. sctp_send() - DEPRECATED

This function is deprecated; sctp_sendv() should be used instead.

An implementation may provide another alternative function or system
call to assist an application with the sending of data without the
use of the cmsghdr structures.

The function prototype is

ssize_t sctp_send(int sd,
const void *msg,
size_t len,
const struct sctp_sndrcvinfo *sinfo,
int flags);

and the arguments are

sd: The socket descriptor.

msg: The message to be sent.

len: The length of the message.

sinfo: A pointer to an sctp_sndrcvinfo structure used as described
in Section 5.3.2 for a sendmsg() call.

flags: The same flags as used by the sendmsg() call flags (e.g.,
MSG_DONTROUTE).

The call returns the number of bytes sent, or -1 if an error
occurred. The variable errno is then set appropriately.

This function call may also be used to terminate an association using
an association identifier by setting the sinfo.sinfo_flags to
SCTP_EOF and the sinfo.sinfo_assoc_id to the association that needs
to be terminated. In such a case, len can be zero.

Stewart, et al. Informational [Page 96]
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Using sctp_send() on a non-connected one-to-one style socket for
implicit connection setup may or may not work, depending on the SCTP
implementation.

Sending a message using sctp_send() is atomic unless explicit EOR
marking is enabled on the socket specified by sd.

9.11. sctp_sendx() - DEPRECATED

This function is deprecated; sctp_sendv() should be used instead.

An implementation may provide another alternative function or system
call to assist an application with the sending of data without the
use of the cmsghdr structure, and to provide a list of addresses.
The list of addresses is provided for implicit association setup. In
such a case, the list of addresses serves the same purpose as the
addresses given in sctp_connectx() (see Section 9.9).

The function prototype is

ssize_t sctp_sendx(int sd,
const void *msg,
size_t len,
struct sockaddr *addrs,
int addrcnt,
struct sctp_sndrcvinfo *sinfo,
int flags);

and the arguments are

sd: The socket descriptor.

msg: The message to be sent.

len: The length of the message.

addrs: An array of addresses.

addrcnt: The number of addresses in the array.

sinfo: A pointer to an sctp_sndrcvinfo structure used as described
in Section 5.3.2 for a sendmsg() call.

flags: The same flags as used by the sendmsg() call flags (e.g.,
MSG_DONTROUTE).

The call returns the number of bytes sent, or -1 if an error
occurred. The variable errno is then set appropriately.

Stewart, et al. Informational [Page 97]
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Note that in the case of implicit connection setup, on return from
this call, the sinfo_assoc_id field of the sinfo structure will
contain the new association identifier.

Sending a message using sctp_sendx() is atomic unless explicit EOR
marking is enabled on the socket specified by sd.

Using sctp_sendx() on a non-connected one-to-one style socket for
implicit connection setup may or may not work, depending on the SCTP
implementation.

9.12. sctp_sendv()

The function prototype is

ssize_t sctp_sendv(int sd,
const struct iovec *iov,
int iovcnt,
struct sockaddr *addrs,
int addrcnt,
void *info,
socklen_t infolen,
unsigned int infotype,
int flags);

The function sctp_sendv() provides an extensible way for an
application to communicate different send attributes to the SCTP
stack when sending a message. An implementation may provide
sctp_sendv() as a library function or a system call.

This document defines three types of attributes that can be used to
describe a message to be sent. They are struct sctp_sndinfo
(Section 5.3.4), struct sctp_prinfo (Section 5.3.7), and struct
sctp_authinfo (Section 5.3.8). The following structure,
sctp_sendv_spa, is defined to be used when more than one of the above
attributes are needed to describe a message to be sent.

struct sctp_sendv_spa {
uint32_t sendv_flags;
struct sctp_sndinfo sendv_sndinfo;
struct sctp_prinfo sendv_prinfo;
struct sctp_authinfo sendv_authinfo;
};

Stewart, et al. Informational [Page 98]
RFC 6458 SCTP Sockets API December 2011>ianaift:ethernetCsmacd</type>
<ipv4 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
<address>
<ip>192.0.2.1</ip>
<prefix-length>24</prefix-length>
</address>
</ipv4>
<ipv6 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
<mtu>1280</mtu>
<address>
<ip>2001:db8::10</ip>
<prefix-length>32</prefix-length>
</address>
<dup-addr-detect-transmits>0</dup-addr-detect-transmits>
</ipv6>
</interface>
</interfaces>
</data>
</rpc-reply>

Bjorklund Standards Track [Page 32]
RFC 8344 YANG IP Management March 2018

Appendix B. Example: NETCONF <get-data> Reply

This section gives an example of a reply to the NETCONF <get-data>
request for the operational state datastore for a device that
implements the data model defined in this document.

This example uses the "origin" annotation, which is defined in the
module "ietf-origin" [RFC8342].

<rpc-reply
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
message-id="101">
<data xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-datastores">
<interfaces
xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type"
xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin">

<interface or:origin="or:intended">
<name>eth0</name>
<type>ianaift:ethernetCsmacd</type>

<ipv4 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
<enabled or:origin="or:default">true</enabled>
<forwarding or:origin="or:default">false</forwarding>
<mtu or:origin="or:system">1500</mtu>
<address>
<ip>192.0.2.1</ip>
<prefix-length>24</prefix-length>
<origin>static</origin>
</address>
<neighbor or:origin="or:learned">
<ip>192.0.2.2</ip>
<link-layer-address>
00:00:5E:00:53:AB
</link-layer-address>
</neighbor>
</ipv4>
<ipv6 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
<enabled or:origin="or:default">true</enabled>
<forwarding or:origin="or:default">false</forwarding>
&

The sendv_flags field holds a bitwise OR of SCTP_SEND_SNDINFO_VALID,
SCTP_SEND_PRINFO_VALID, and SCTP_SEND_AUTHINFO_VALID indicating if
the sendv_sndinfo/sendv_prinfo/sendv_authinfo fields contain valid
information.

In future, when new send attributes are needed, new structures can be
defined. But those new structures do not need to be based on any of
the above defined structures.

The function takes the following arguments:

sd: The socket descriptor.

iov: The gather buffer. The data in the buffer is treated as a
single user message.

iovcnt: The number of elements in iov.

addrs: An array of addresses to be used to set up an association or
a single address to be used to send the message. NULL is passed
in if the caller neither wants to set up an association nor wants
to send the message to a specific address.

addrcnt: The number of addresses in the addrs array.

info: A pointer to the buffer containing the attribute associated
with the message to be sent. The type is indicated by the
info_type parameter.

infolen: The length of info, in bytes.

infotype: Identifies the type of the information provided in info.
The current defined values are as follows:

SCTP_SENDV_NOINFO: No information is provided. The parameter
info is a NULL pointer, and infolen is 0.

SCTP_SENDV_SNDINFO: The parameter info is pointing to a struct
sctp_sndinfo.

SCTP_SENDV_PRINFO: The parameter info is pointing to a struct
sctp_prinfo.

SCTP_SENDV_AUTHINFO: The parameter info is pointing to a struct
sctp_authinfo.

SCTP_SENDV_SPA: The parameter info is pointing to a struct
sctp_sendv_spa.

Stewart, et al. Informational [Page 99]
RFC 6458 SCTP Sockets API December 2011

flags: The same flags as used by the sendmsg() call flags (e.g.,
MSG_DONTROUTE).

The call returns the number of bytes sent, or -1 if an error
occurred. The variable errno is then set appropriately.

A note on the one-to-many style socket: The struct sctp_sndinfo
attribute must always be used in order to specify the association on
which the message is to be sent. The only case where it is not
needed is when this call is used to set up a new association.

The caller provides a list of addresses in the addrs parameter to set
up an association. This function will behave like calling
sctp_connectx() (see Section 9.9), first using the list of addresses
and then calling sendmsg() with the given message and attributes.
For a one-to-many style socket, if the struct sctp_sndinfo attribute
is provided, the snd_assoc_id field must be 0. When this function
returns, the snd_assoc_id field will contain the association
identifier of the newly established association. Note that the
struct sctp_sndinfo attribute is not required to set up an
association for a one-to-many style socket. If this attribute is not
provided, the caller can enable the SCTP_ASSOC_CHANGE notification
and use the SCTP_COMM_UP message to find out the association
identifier.

If the caller wants to send the message to a specific peer address
(hence overriding the primary address), it can provide the specific
address in the addrs parameter and provide a struct sctp_sndinfo
attribute with the field snd_flags set to SCTP_ADDR_OVER.

This function call may also be used to terminate an association. The
caller provides an sctp_sndinfo attribute with the snd_flags set to
SCTP_EOF. In this case, len would be zero.

Sending a message using sctp_sendv() is atomic unless explicit EOR
marking is enabled on the socket specified by sd.

Stewart, et al. Informational [Page 100]
RFC 6458 SCTP Sockets API December 2011

9.13. sctp_recvv()

The function prototype is

ssize_t sctp_recvv(int sd,
const struct iovec *iov,
int iovlen,
struct sockaddr *from,
socklen_t *fromlen,
void *info,
socklen_t *infolen,
unsigned int *infotype,
int *flags);

The function sctp_recvv() provides an extensible way for the SCTP
stack to pass up different SCTP attributes associated with a received
message to an application. An implementation may provide
sctp_recvv() as a library function or as a system call.

This document defines two types of attributes that can be returned by
this call: the attribute of the received message and the attribute of
the next message in the receive buffer. The caller enables the
SCTP_RECVRCVINFO and SCTP_RECVNXTINFO socket options, respectively,
to receive these attributes. Attributes of the received message are
returned in struct sctp_rcvinfo (Section 5.3.5), and attributes of
the next message are returned in struct sctp_nxtinfo (Section 5.3.6).
If both options are enabled, both attributes are returned using the
following structure.

struct sctp_recvv_rn {
struct sctp_rcvinfo recvv_rcvinfo;
struct sctp_nxtinfo recvv_nxtinfo;
};

In future, new structures can be defined to hold new types of
attributes. The new structures do not need to be based on struct
sctp_recvv_rn or struct sctp_rcvinfo.

This function takes the following arguments:

sd: The socket descriptor.

iov: The scatter buffer. Only one user message is returned in this
buffer.

iovlen: The number of elements in iov.

Stewart, et al. Informational [Page 101]
RFC 6458 SCTP Sockets API December 2011

from: A pointer to an address to be filled with the sender of the
received message's address.

fromlen: An in/out parameter describing the from length.

info: A pointer to the buffer to hold the attributes of the received
message. The structure type of info is determined by the
info_type parameter.

infolen: An in/out parameter describing the size of the info buffer.

infotype: On return, *info_type is set to the type of the info
buffer. The current defined values are as follows:

SCTP_RECVV_NOINFO: If both SCTP_RECVRCVINFO and SCTP_RECVNXTINFO
options are not enabled, no attribute will be returned. If
only the SCTP_RECVNXTINFO option is enabled but there is no
next message in the buffer, no attribute will be returned. In
these cases, *info_type will be set to SCTP_RECVV_NOINFO.

SCTP_RECVV_RCVINFO: The type of info is struct sctp_rcvinfo, and
the attribute relates to the received message.

SCTP_RECVV_NXTINFO: The type of info is struct sctp_nxtinfo, and
the attribute relates to the next message in the receive
buffer. This is the case when only the SCTP_RECVNXTINFO option
is enabled and there is a next message in the buffer.

SCTP_RECVV_RN: The type of info is struct sctp_recvv_rn. The
recvv_rcvinfo field is the attribute of the received message,
and the recvv_nxtinfo field is the attribute of the next
message in the buffer. This is the case when both
SCTP_RECVRCVINFO and SCTP_RECVNXTINFO options are enabled and
there is a next message in the receive buffer.

flags: A pointer to an integer to be filled with any message flags
(e.g., MSG_NOTIFICATION). Note that this field is an in/out
parameter. Options for the receive may also be passed into the
value (e.g., MSG_PEEK). On return from the call, the flags value
will be different than what was sent in to the call. If
implemented via a recvmsg() call, the flags should only contain
the value of the flags from the recvmsg() call when calling
sctp_recvv(), and on return it has the value from msg_flags.

The call returns the number of bytes received, or -1 if an error
occurred. The variable errno is then set appropriately.

Stewart, et al. Informational [Page 102]
RFC 6458 SCTP Sockets API December 2011

10. Security Considerations

Many TCP and UDP implementations reserve port numbers below 1024 for
privileged users. If the target platform supports privileged users,
the SCTP implementation should restrict the ability to call bind() or
sctp_bindx() on these port numbers to privileged users.

Similarly, unprivileged users should not be able to set protocol
parameters that could result in the congestion control algorithm
being more aggressive than permitted on the public Internet. These
parameters are as follows:

o struct sctp_rtoinfo

If an unprivileged user inherits a one-to-many style socket with open
associations on a privileged port, accepting new associations might
be permitted, but opening new associations should not be permitted.
This could be relevant for the r* family (rsh, rlogin, rwho, ...) of
protocols.

Applications using the one-to-many style sockets and using the
interleave level (if 0) are subject to denial-of-service attacks, as
described in Section 8.1.20.

Applications needing transport layer security can use Datagram
Transport Layer Security/SCTP (DTLS/SCTP) as specified in [RFC6083].
This can be implemented using the sockets API described in this
document.

11. Acknowledgments

Special acknowledgment is given to Ken Fujita, Jonathan Woods,
Qiaobing Xie, and La Monte Yarroll, who helped extensively in the
early formation of this document.

The authors also wish to thank Kavitha Baratakke, Mike Bartlett,
Martin Becke, Jon Berger, Mark Butler, Thomas Dreibholz, Andreas
Fink, Scott Kimble, Jonathan Leighton, Renee Revis, Irene Ruengeler,
Dan Wing, and many others on the TSVWG mailing list for contributing
valuable comments.

A special thanks to Phillip Conrad, for his suggested text, quick and
constructive insights, and most of all his persistent fighting to
keep the interface to SCTP usable for the application programmer.

Stewart, et al. Informational [Page 103]
RFC 6458 SCTP Sockets API December 2011

12. References

12.1. Normative References

[IEEE-1003.1-2008]
Institute of Electrical and Electronics Engineers,
"Information Technology - Portable Operating System
Interface (POSIX)", IEEE Standard 1003.1, 2008.

[RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W.
Stevens, "Basic Socket Interface Extensions for IPv6",
RFC 3493, February 2003.

[RFC3542] Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei,
"Advanced Sockets Application Program Interface (API) for
IPv6", RFC 3542, May 2003.

[RFC3758] Stewart, R., Ramalho, M., Xie, Q., Tuexen, M., and P.
Conrad, "Stream Control Transmission Protocol (SCTP)
Partial Reliability Extension", RFC 3758, May 2004.

[RFC4895] Tuexen, M., Stewart, R., Lei, P., and E. Rescorla,
"Authenticated Chunks for the Stream Control Transmission
Protocol (SCTP)", RFC 4895, August 2007.

[RFC4960] Stewart, R., Ed., "Stream Control Transmission Protocol",
RFC 4960, September 2007.

[RFC5061] Stewart, R., Xie, Q., Tuexen, M., Maruyama, S., and M.
Kozuka, "Stream Control Transmission Protocol (SCTP)
Dynamic Address Reconfiguration", RFC 5061,
September 2007.

12.2. Informative References

[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
August 1980.

[RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, September 1981.

[RFC1644] Braden, R., "T/TCP -- TCP Extensions for Transactions
Functional Specification", RFC 1644, July 1994.

Stewart, et al. Informational [Page 104]
RFC 6458 SCTP Sockets API December 2011

[RFC6083] Tuexen, M., Seggelmann, R., and E. Rescorla, "Datagram
Transport Layer Security (DTLS) for Stream Control
Transmission Protocol (SCTP)", RFC 6083, January 2011.

[RFC6247] Eggert, L., "Moving the Undeployed TCP Extensions RFC
1072, RFC 1106, RFC 1110, RFC 1145, RFC 1146, RFC 1379,
RFC 1644, and RFC 1693 to Historic Status", RFC 6247,
May 2011.

Stewart, et al. Informational [Page 105]
RFC 6458 SCTP Sockets API December 2011

Appendix A. Example Using One-to-One Style Sockets

The following code is an implementation of a simple client that sends
a number of messages marked for unordered delivery to an echo server
making use of all outgoing streams. The example shows how to use
some features of one-to-one style IPv4 SCTP sockets, including

o Creating and connecting an SCTP socket.

o Making a request to negotiate a number of outgoing streams.

o Determining the negotiated number of outgoing streams.

o Setting an adaptation layer indication.

o Sending messages with a given payload protocol identifier on a
particular stream using sctp_sendv().

<CODE BEGINS>
/*

Redistribution and use in source and binary forms, with
or without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents (http://trustee.ietf.org/license-info).

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

#define PORT 9
#define ADDR "127.0.0.1<mtu>1280</mtu>

Bjorklund Standards Track [Page 33]
RFC 8344 YANG IP Management March 2018

<address>
<ip>2001:db8::10</ip>
<prefix-length>32</prefix-length>
<origin>static</origin>
<status>preferred</status>
</address>
<address or:origin="or:learned">
<ip>2001:db8::1:100</ip>
<prefix-length>32</prefix-length>
<origin>dhcp</origin>
<status>preferred</status>
</address>
<dup-addr-detect-transmits>0</dup-addr-detect-transmits>
<neighbor or:origin="or:learned">
<ip>2001:db8::1</ip>
<link-layer-address>
00:00:5E:00:53:AB
</link-layer-address>
<origin>dynamic</origin>
<is-router/>
<state>reachable</state>
</neighbor>
<neighbor or:origin="or:learned">
<ip>2001:db8::4</ip>
<origin>dynamic</origin>
<state>incomplete</state>
</neighbor>
</ipv6>
</interface>
</interfaces>
</data>
</rpc-reply>

Acknowledgments

The author wishes to thank Jeffrey Lange, Ladislav Lhotka, Juergen
Schoenwaelder, and Dave Thaler for their helpful comments.

Author's Address

Martin Bjorklund
Tail-f Systems

Email: mbj@tail-f.com

Bjorklund Standards Track [Page 34]

A YANG Data Model for IP Management RFC 8344

A YANG Data Model for IP Management
RFC 8344