$ sudo apt-get install libsctp-dev lksctp-tools下面有一個範例程式：
server.c
//==============================include header file============================
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//=============================================================================
//==============================define variable================================
#define BUFFERSIZE 8192
#define SERV_PORT 9877
#define LISTENQ 1024
//=============================================================================
int main(int argc,char **argv)
{
int echo_to_all = 0;
int ret_value;
int sock_fd;
int msg_flags; // 記錄要傳送訊息時的相關設定
char readbuf[BUFFERSIZE];
struct sockaddr_in servaddr,cliaddr;
struct sctp_sndrcvinfo sri; // 記錄send, recv, association的相關資訊
struct sctp_event_subscribe evnts;
int stream_increment = 1;
socklen_t len;
size_t rd_sz; // size_t指的就是unsigned long:rd_sz表示recv,send-size
if (argc == 2) {
// 把字串轉換成數字
stream_increment = atoi(argv[1]);
}
// 建立socket的型態為SCTP的one-to-many的型態
sock_fd = socket(AF_INET,SOCK_SEQPACKET,IPPROTO_SCTP);
if (sock_fd == -1) {
printf("socket error\n");
exit(-1);
}
// 初始化server address的設定
memset(&servaddr,0,sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(SERV_PORT);
// 把socket與所建立的address綁在一起
ret_value = bind(sock_fd,(struct sockaddr *) &servaddr,sizeof(servaddr));
if (ret_value == -1) {
printf("bind error\n");
exit(-1);
}
// Set up for notifications of internet
bzero(&evnts,sizeof(evnts));
evnts.sctp_data_io_event = 1; // 使得sctp_sndrcvinfo可以伴隨資料傳送過來
ret_value = setsockopt(sock_fd,IPPROTO_SCTP,SCTP_EVENTS,&evnts,sizeof(evnts));
if (ret_value == -1) {
printf("setsockopt error\n");
exit(-1);
}
// 設定等待多少個client端連線
ret_value = listen(sock_fd,LISTENQ);
if (ret_value == -1) {
printf("listen error\n");
exit(-1);
}
printf("start wait...\n");
for (;;) {
len = sizeof(struct sockaddr_in);
// 等待client端連線
rd_sz = sctp_recvmsg(sock_fd,readbuf,sizeof(readbuf),(struct sockaddr *) &cliaddr,&len,&sri,&msg_flags);
if (stream_increment) {
sri.sinfo_stream++;
if (sri.sinfo_stream >= 100) {
sri.sinfo_stream = 0;
}
}
// 把接收到的資料回送給client
ret_value = sctp_sendmsg(sock_fd,readbuf,rd_sz,(struct sockaddr *) &cliaddr,len,sri.sinfo_ppid,sri.sinfo_flags,sri.sinfo_stream,0,0);
if (ret_value == -1) {
printf("sctp_sendmsg error\n");
exit(-1);
}
}
return 0;
}client.c
//==============================include header file============================
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//=============================================================================
//==============================define variable================================
#define BUFFERSIZE 8192
#define SERV_PORT 9877
#define LISTENQ 1024
#define MAXLINE 4096
#define SCTP_MAXLINE 800
#define SERV_MAX_SCTP_STRM 10
//=============================================================================
//==============================define function================================
void sctpstr_cli(FILE *fp,int sock_fd,struct sockaddr *to,socklen_t tolen);
void sctpstr_cli_echoall(FILE *fp,int sock_fd,struct sockaddr *to,socklen_t tolen);
//=============================================================================
//==============================main function==================================
int main(int argc,char **argv)
{
int sock_fd; // client所建立的socket
struct sockaddr_in servaddr; // 記錄server的sockaddr_in的相關資訊
struct sctp_event_subscribe evnts; // 設定要觀查的事件
int echo_to_all = 0; // 決定server是否有多個
int ret_value = 0;
// 沒有設定server的ip
if (argc < 2) {
printf("Missing host argument - use '%s host [echo]'\n",argv[0]);
exit(-1);
}
// 設定多個server的ip
if (argc > 2) {
printf("Echoing messages to all streams\n");
echo_to_all = 1;
}
// init setting
sock_fd = socket(AF_INET,SOCK_SEQPACKET,IPPROTO_SCTP); // 設定為sctp為one-to-many的型態
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY); // 感覺這一行應該是多餘的
servaddr.sin_port = htons(SERV_PORT);
ret_value = inet_pton(AF_INET,argv[1],&servaddr.sin_addr); // 把字串轉換成網路位元組序二進位值,當回傳為1時,表轉換
成功
if (ret_value != 1) {
printf("translate server ip address error!!\n");
exit(-1);
}
// 設定要觀察的事件,所有都清除,只設定io event
memset(&evnts,0,sizeof(evnts));
evnts.sctp_data_io_event = 1; // 監控sctp的data的io事件:1是打開的意思
ret_value = setsockopt(sock_fd,IPPROTO_SCTP,SCTP_EVENTS,&evnts,sizeof(evnts));
if (ret_value == -1) {
printf("setsockopt error\n");
exit(-1);
}
if (echo_to_all == 0) {
// 此client只傳給一個server
sctpstr_cli(stdin,sock_fd,(struct sockaddr *) &servaddr,sizeof(servaddr));
}
else {
// 要設定傳給許多個server
sctpstr_cli_echoall(stdin,sock_fd,(struct sockaddr *) &servaddr,sizeof(servaddr));
}
close(sock_fd);
return 0;
}
//=============================================================================
//==============================function implemen==============================
void sctpstr_cli(FILE *fp,int sock_fd,struct sockaddr *to,socklen_t tolen)
{
struct sockaddr_in peeraddr; // client的相關位址資料
struct sctp_sndrcvinfo sri; // send and recv端的資料
char sendline[MAXLINE],recvline[MAXLINE];
socklen_t len;
int out_sz,rd_sz;
int msg_flags;
int ret_value=0;
bzero(&sri,sizeof(sri));
// block住,等待client端輸入
while (fgets(sendline,MAXLINE,fp) != NULL) {
if (sendline[0] != '[') {
printf("Error, line must be of the form '[streamnum]text'\n");
continue;
}
// string to long integer,表示sendline這一個字串是base在10進位去轉換
// 透過設定的stream number來傳送資料
sri.sinfo_stream = strtol(&sendline[1],NULL,0);
out_sz = strlen(sendline); // 輸入字串的長度,用來記錄等一下要傳送幾個字元
ret_value = sctp_sendmsg(sock_fd,sendline,out_sz,to,tolen,0,0,sri.sinfo_stream,0,0);
if (ret_value == -1) {
printf("sctp_sendmsg error\n");
exit(-1);
}
len = sizeof(peeraddr);
rd_sz = sctp_recvmsg(sock_fd,recvline,sizeof(recvline),(struct sockaddr *) &peeraddr,&len,&sri,&msg_flags);
printf("From str:%d seq:%d (assoc:0x%x):",sri.sinfo_stream,sri.sinfo_ssn,(u_int) sri.sinfo_assoc_id);
printf("%.*s",rd_sz,recvline);
}
}
void sctpstr_cli_echoall(FILE *fp,int sock_fd,struct sockaddr *to,socklen_t tolen)
{
struct sockaddr_in peeraddr;
struct sctp_sndrcvinfo sri;
char sendline[SCTP_MAXLINE], recvline[SCTP_MAXLINE];
socklen_t len;
int rd_sz,i,strsz;
int msg_flags;
int ret_value=0;
// the client initializes the sri structure used to set up the stream it will be sending and receiving from
bzero(sendline,sizeof(sendline));
bzero(&sri,sizeof(sri));
while(fgets(sendline,SCTP_MAXLINE-9,fp) != NULL) {
strsz = strlen(sendline);
// delete the newline character that is at the end of the buffer
if (sendline[strsz-1] == '\n') {
sendline[strsz-1]='\0';
strsz--;
}
// 傳送SERV_MAX_SCTP_STRM筆資料給server
for (i=0;i<SERV_MAX_SCTP_STRM;i++) {
snprintf(sendline+strsz,sizeof(sendline)-strsz,".msg.%d",i);
ret_value = sctp_sendmsg(sock_fd,sendline,sizeof(sendline),to,tolen,0,0,i,0,0);
if (ret_value == -1) {
printf("sctp_sendmsg error\n");
exit(-1);
}
}
// 由server接收SERV_MAX_SCTP_STRM筆資料
for (i=0;i<SERV_MAX_SCTP_STRM;i++) {
len = sizeof(peeraddr);
rd_sz = sctp_recvmsg(sock_fd,recvline,sizeof(recvline),(struct sockaddr *) &peeraddr,&len,&sri,&msg_flags);
printf("From str:%d seq:%d (assoc:0x%x):",sri.sinfo_stream,sri.sinfo_ssn,(u_int) sri.sinfo_assoc_id);
printf("%.*s\n",rd_sz,recvline);
}
}
}編譯：
$ gcc server.c -o server -lsctp
$ gcc client.c -o client -lsctp
$ ./server &
$ ./client 127.0.0.1
> [1]Hello World!!參考資料：
網絡編程基礎--學習筆記
UNIX Network Programming
sctp_exporter.cc
SCTP Ancillary Data Structures
Stream Control Transmission Protocol
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