SCTP Programmer's Guide

sd = socket(PF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);

sd = socket(PF_INET6, SOCK_SEQPACKET, IPPROTO_SCTP);

where:

SOCK_SEQPACKET

Indicates the creation of a one-to-one or one-to-many style

socket.

IPProto_SCTP

Specifies the type of the protocol.

PF_INET

Specifies the IPv4 domain.

PF_INET6

Specifies the IPv6 domain.

The first syntax of socket() creates an endpoint that can use only IPv4 addresses,

while the second syntax creates an endpoint that can use both IPv6 and IPv4 addresses.

The bind() Socket API

Applications use bind() to specify the local address to which an SCTP endpoint must

associate.

An SCTP endpoint can be associated with multiple addresses. The sctp_bindx()

API enables applications to associate with multiple addresses. For information on

sctp_bindx(), see “The sctp_bindx() SCTP Socket API” (page 61). These addresses,

associated with a socket, are eligible transport addresses for the endpoint to send and

receive data. The endpoint also presents these addresses to its peers during the

association initialization process. To accept new associations on the socket, applications

must call listen(), after calling bind(). For information on listen(), see “The

listen() Socket API” (page 45).

Following is the syntax for the bind() socket API:

ret = bind(int sd, struct sockaddr *addr, socklen_t addrlen);

where:

sd Represents the socket descriptor returned by the socket() call.

addr

Represents the address structure (struct sockaddr_in or struct

sockaddr_in6).

addrlen

Represents the size of the address structure.

If sd is an IPv4 socket, the address passed must be an IPv4 address. If sd is an IPv6

socket, the address passed can be either an IPv4 or an IPv6 address.

Applications cannot call bind() multiple times to associate multiple addresses to an

endpoint. After the first call to bind(), all the subsequent calls will return an error.

If addr is specified as a wildcard (INADDR_ANY for an IPv4 address, or

IN6ADDR_ANY_INIT or in6addr_any for an IPv6 address), the operating system

associates the endpoint with an optimal address set of the available interfaces.

If a bind() call is not called before a sendmsg() call that initiates a new association,

the endpoint picks a transient port and chooses an address set that is equivalent to

50 SCTP Socket APIs