SCTP_CONNECTX(3)          Linux Programmer's Manual         SCTP_CONNECTX(3)

NAME         top

       sctp_connectx  - initiate a connection on an SCTP socket using multi‐
       ple destination addresses.

SYNOPSIS         top

       #include <sys/types.h>
       #include <sys/socket.h>
       #include <netinet/sctp.h>

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

DESCRIPTION         top

       sctp_connectx initiates a connection to a set of addresses passed in
       the array addrs to/from the socket sd.  addrcnt is the number of
       addresses in the array.

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

       addrs is a pointer to an array of one or more socket addresses. Each
       address is contained in its appropriate structure(i.e. struct
       sockaddr_in or struct sockaddr_in6). The family of the address type
       must be used to distinguish the address length. The caller specifies
       the number of addresses in the array with addrcnt.

       id is a pointer to the association id and, if provided, will be set
       to the identifier of the newly created association.

RETURN VALUE         top

       On success, 0 is returned. On failure, -1 is returned, and errno is
       set appropriately.

ERRORS         top

       EBADF  sd is not a valid descriptor.

              sd is a descriptor for a file, not a socket.

       EFAULT Error while copying in or out from the user address space.

       EINVAL Invalid port or address.

       EACCES The address is protected, and the user is not the super-user.

              The socket is already connected.

              No one listening on the remote address.

              Timeout while attempting connection. The server may be too
              busy to accept new connections. Note that for IP sockets the
              timeout may be very long when syncookies are enabled on the

              Network is unreachable.

              Local address is already in use.

              The socket is non-blocking and the connection cannot be
              completed immediately.  It is possible to select(2) or poll(2)
              for completion by selecting the socket for writing. After
              select indicates writability, use getsockopt(2) to read the
              SO_ERROR option at level SOL_SOCKET to determine whether
              connect completed successfully (SO_ERROR is zero) or
              unsuccessfully (SO_ERROR is one of the usual error codes
              listed here, explaining the reason for the failure).

              The socket is non-blocking and a previous connection attempt
              has not yet been completed.

       EAGAIN No more free local ports or insufficient entries in the
              routing cache. For PF_INET see the
              net.ipv4.ip_local_port_range sysctl in ip(7) on how to
              increase the number of local ports.

              The passed address didn't have the correct address family in
              its sa_family field.

              The user tried to connect to a broadcast address without
              having the socket broadcast flag enabled or the connection
              request failed because of a local firewall rule.

SEE ALSO         top

       sctp(7) sctp_bindx(3), sctp_sendmsg(3), sctp_send(3),
       sctp_recvmsg(3), sctp_peeloff(3), sctp_getpaddrs(3),
       sctp_getladdrs(3), sctp_opt_info(3),

COLOPHON         top

       This page is part of the lksctp-tools (Linux kernel SCTP tools)
       project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug report for this manual page,
       send it to  This page was obtained from the
       project's upstream Git repository 
       ⟨git://⟩ on 2017-03-13.  If you dis‐
       cover any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail

Linux 2.6                        2005-10-25                 SCTP_CONNECTX(3)