学步园

以下源码是基于linux操作系统的。实现了基于SCTP协议的一对多模式的服务器端代码，该段不但处理的用户数据，而且处理了的通知类的消息，即notification消息。

#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 <stdlib.h>
#include <unistd.h>

static void handle_event(void *buf)
{

	struct sctp_assoc_change   *sac;
	struct sctp_send_failed    *ssf;
	struct sctp_paddr_change   *spc;
	struct sctp_remote_error   *sre;
	struct sctp_shutdown_event *sse;

	union sctp_notification  *snp;

	snp = (sctp_notification*)buf;
	switch (snp->sn_header.sn_type)
	{

		case SCTP_ASSOC_CHANGE:
		{
			sac = &snp->sn_assoc_change;
			printf("assoc_change: state=%hu, error=%hu, instr=%hu outstr=%hu associd=%d\n", 
				sac->sac_state, 
				sac->sac_error,
				sac->sac_inbound_streams, 
				sac->sac_outbound_streams,
				sac->sac_assoc_id);
			break;
		}
		case SCTP_SEND_FAILED:
		{
			ssf = &snp->sn_send_failed;
			printf("sendfailed: len=%hu err=%d assoc_i=%d ssf_data=%d\n", ssf->ssf_length, ssf->ssf_error, ssf->ssf_assoc_id, ssf->ssf_data[0]);
			break;
		}
		case SCTP_PEER_ADDR_CHANGE:
		{
			spc = &snp->sn_paddr_change;
			struct sockaddr_in  *sin = (struct sockaddr_in *)&spc->spc_aaddr;
			char  addrbuf[INET6_ADDRSTRLEN];
			inet_ntop(AF_INET, &sin->sin_addr, addrbuf, INET6_ADDRSTRLEN);
			printf("peeraddrchange: %s state=%d, error=%d\n", addrbuf, spc->spc_state, spc->spc_error);
			break;
		}
		case SCTP_REMOTE_ERROR:
		{
			sre = &snp->sn_remote_error;
			printf("remote_error: err=%hu len=%hu\n", ntohs(sre->sre_error), ntohs(sre->sre_length));
			break;
		}

		case SCTP_SHUTDOWN_EVENT:
		{
			sse = &snp->sn_shutdown_event;
			printf("shutdown event: assoc_id=%d\n", sse->sse_assoc_id);
			break;
		}
		default:
		{
			printf("unknown type: %hu\n", snp->sn_header.sn_type);
			break;
		}
	}
}


int main(int agrc, char* agrv[])
{
	/* Create a 1-to-many style SCTP socket. */
	int fd = -1;
	if ((fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP)) < 0)
	{
		perror("socket");
		exit(1);
	}

     /* Enable all notifications and events */
	struct sctp_event_subscribe event;
     event.sctp_data_io_event = 1;
     event.sctp_association_event = 1;
     event.sctp_address_event = 1;
     event.sctp_send_failure_event = 1;
     event.sctp_peer_error_event = 1;
     event.sctp_shutdown_event = 1;
     event.sctp_partial_delivery_event = 1;
     event.sctp_adaption_layer_event = 1;
     if (setsockopt(fd, IPPROTO_SCTP, SCTP_EVENTS, &event, sizeof(event)) != 0)
	{
          perror("setevent failed");
		exit(1);
	}

	/* Configure auto-close timer. */
	int timeout = 5;
	if (setsockopt(fd, IPPROTO_SCTP, SCTP_AUTOCLOSE, &timeout, 4) < 0) 
	{
		perror("setsockopt SCTP_AUTOCLOSE");
		exit(1);
	}


	/* Bind the socket to all local addresses. */
	struct sockaddr_in sin;
	bzero((char*)&sin, sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_port = htons(19000);
	sin.sin_addr.s_addr = inet_addr("192.168.10.120");
	if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)) == -1)
	{
		perror("bind");
		exit(1);
	}

	/* Enable accepting associations. */
	if (listen(fd, 1) < 0) 
	{
		perror("listen");
		exit(1);
	}

	char buffer[256];
	int bufferlen = 256;
	bzero(buffer, bufferlen);
	
	struct sockaddr_in clientaddr;
	int fromlen = sizeof(clientaddr);
	struct sctp_sndrcvinfo sndrcvinfo;
	int msg_flag;
	
	while(true) 
	{ 
	
		int length = sctp_recvmsg(fd, buffer, bufferlen, (struct sockaddr*)&clientaddr, (socklen_t*)&fromlen, &sndrcvinfo, &msg_flag);

		if (msg_flag &  MSG_NOTIFICATION)
		{
			printf("****************************************************\n");
			printf("Event: notificaiton length=%d\n", length);
			handle_event((void*)buffer);
		}
		else
		{
			printf("****************************************************\n");
			printf("Event: data event length=%d\n", length);
			char addrbuf[100];
			inet_ntop(AF_INET, &clientaddr.sin_addr, addrbuf, INET6_ADDRSTRLEN);
			int port = ntohs(clientaddr.sin_port);
			printf("data from=%s:%d\n", addrbuf, port);
			printf("data=%s\n", buffer);
		}
	}


	if (close(fd) < 0) 
	{
		perror("close");
		exit(1);
	}

	return (0);
}