SCTP客户端与服务器

 /**
  * @brief - Send a message, using advanced SCTP features
  * The sctp_sendmsg() function allows you to send extra information to a remote application.
  * Using advanced SCTP features, you can send a message through a specified stream,
  * pass extra opaque information to a remote application, or define a timeout for the particular message.
  *
  * @header - #include <netinet/sctp.h>
  *
  * @return ssize_t - The number of bytes sent, or -1 if an error occurs (errno is set).
  *
  * @ERRORS
  * EBADF
  *     An invalid descriptor was specified.
  * EDESTADDRREQ
  *     A destination address is required.
  * EFAULT
  *     An invalid user space address was specified for a parameter.
  * EMSGSIZE
  *     The socket requires that the message be sent atomically, but the size of the message made this impossible.
  * ENOBUFS
  *     The system couldn't allocate an internal buffer. The operation may succeed when buffers become available.
  * ENOTSOCK
  *     The argument s isn't a socket.
  * EWOULDBLOCK
  *     The socket is marked nonblocking and the requested operation would block.
  */
 ssize_t sctp_sendmsg(int s,                             /*! Socket descriptor. */
                      const void *msg,         /*! Message to be sent. */
                      size_t len,                     /*! Length of the message. */
                      struct sockaddr *to, /*! Destination address of the message. */
                      socklen_t tolen,         /*! Length of the destination address. */
                      uint32_t ppid,             /*! An opaque unsigned value that is passed to the remote end in each user message.
                                                                         The byte order issues are not accounted for and this information is passed opaquely
                                                                           by the SCTP stack from one end to the other. */
                      uint32_t flags,             /*! Flags composed of bitwise OR of these values:
                                                                          MSG_UNORDERED
                                                                              This flag requests the unordered delivery of the message.
                                                                              If the flag is clear, the datagram is considered an ordered send.
                                                                          MSG_ADDR_OVER
                                                                              This flag, in one-to-many style, requests the SCTP stack to override the primary destination address.
                                                                          MSG_ABORT
                                                                              This flag causes the specified association to abort -- by sending
                                                                              an ABORT message to the peer (one-to-many style only).
                                                                          MSG_EOF
                                                                              This flag invokes the SCTP graceful shutdown procedures on the specified association.
                                                                              Graceful shutdown assures that all data enqueued by both endpoints is successfully
                                                                              transmitted before closing the association (one-to-many style only). */
                      uint16_t stream_no,     /*! Message stream number -- for the application to send a message.
                                                                          If a sender specifies an invalid stream number, an error indication is returned and the call fails. */
                      uint32_t timetolive,    /*! Message time to live in milliseconds.
                                                                          The sending side expires the message within the specified time period
                                                                          if the message has not been sent to the peer within this time period.
                                                                          This value overrides any default value set using socket option.
                                                                          If you use a value of 0, it indicates that no timeout should occur on this message. */
                      uint32_t context);        /*! An opaque 32-bit context datum.
                                                                          This value is passed back to the upper layer if an error occurs while sending a message,
                                                                          and is retrieved with each undelivered message. */

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <time.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <netinet/in.h>
 #include <netinet/sctp.h>
 //#include "common.h"
 #define MAX_BUFFER  1024
 #define MY_PORT_NUM 19000
 #define LOCALTIME_STREAM    0
 #define GMT_STREAM   1  

 int main()
 {
     int listenSock, connSock, ret;
     struct sockaddr_in servaddr;
     char buffer[MAX_BUFFER + ];
     time_t currentTime;

     /* Create SCTP TCP-Style. Socket */
     listenSock = socket( AF_INET, SOCK_STREAM, IPPROTO_SCTP ); // 注意这里的IPPROTO_SCTP
     /* Accept connections from any interface */
     bzero( (void *)&servaddr, sizeof(servaddr) );
     servaddr.sin_family = AF_INET;
     servaddr.sin_addr.s_addr = htonl( INADDR_ANY );
     servaddr.sin_port = htons(MY_PORT_NUM);
     /* Bind to the wildcard address (all) and MY_PORT_NUM */
     ret = bind( listenSock,
                 (struct sockaddr *)&servaddr, sizeof(servaddr) );
     /* Place the server socket into the listening state */
     listen( listenSock,  );
     /* Server loop... */
     while(  )
     {
         /* Await a new client connection */
         connSock = accept( listenSock,
                            (struct sockaddr *)NULL, (int *)NULL );
         /* New client socket has connected */
         /* Grab the current time */
         currentTime = time(NULL);
         /* Send local time on stream 0 (local time stream) */
         snprintf( buffer, MAX_BUFFER, "%s\n", ctime(currentTime) );
         ret = sctp_sendmsg( connSock,
                             (void *)buffer, (size_t)strlen(buffer),
                             NULL, , , , LOCALTIME_STREAM, ,  );
         /* Send GMT on stream 1 (GMT stream) */
         snprintf( buffer, MAX_BUFFER, "%s\n",
                   asctime( gmtime( currentTime ) ) );
         ret = sctp_sendmsg( connSock,
                             (void *)buffer, (size_t)strlen(buffer),
                             NULL, , , , GMT_STREAM, ,  );
         /* Close the client connection */
         close( connSock );
     }
     return ;
 }

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <netinet/in.h>
 #include <netinet/sctp.h>
 #include <arpa/inet.h>
 //#include "common.h"
 #define MAX_BUFFER  1024
 #define MY_PORT_NUM 19000
 #define LOCALTIME_STREAM    0
 #define GMT_STREAM   1  

 int main()
 {
     int connSock, in, i, flags;
     struct sockaddr_in servaddr;
     struct sctp_sndrcvinfo sndrcvinfo;
     struct sctp_event_subscribe events;
     char buffer[MAX_BUFFER + ];
     /* Create an SCTP TCP-Style. Socket */
     connSock = socket( AF_INET, SOCK_STREAM, IPPROTO_SCTP );
     /* Specify the peer endpoint to which we'll connect */
     bzero( (void *)&servaddr, sizeof(servaddr) );
     servaddr.sin_family = AF_INET;
     servaddr.sin_port = htons(MY_PORT_NUM);
     servaddr.sin_addr.s_addr = inet_addr( "127.0.0.1" );
     /* Connect to the server */
     connect( connSock, (struct sockaddr *)&servaddr, sizeof(servaddr) );
     /* Enable receipt of SCTP Snd/Rcv Data via sctp_recvmsg */
     memset( (void *)&events, , sizeof(events) );
     events.sctp_data_io_event = ;
     setsockopt( connSock, SOL_SCTP, SCTP_EVENTS,
                 (const void *)&events, sizeof(events) );
     /* Expect two messages from the peer */
     for (i =  ; i <  ; i++)
     {
         in = sctp_recvmsg( connSock, (void *)buffer, sizeof(buffer),
                            (struct sockaddr *)NULL, ,
                            &sndrcvinfo, &flags );
         /* Null terminate the incoming string */
         buffer[in] = ;
         if (sndrcvinfo.sinfo_stream == LOCALTIME_STREAM)
         {
             printf("(Local) %s\n", buffer);
         }
         else if (sndrcvinfo.sinfo_stream == GMT_STREAM)
         {
             printf("(GMT  ) %s\n", buffer);
         }
     }
     /* Close our socket and exit */
     close(connSock);
     return ;
 }