RTSP服务器：RTSP协议实现（与vlc交互）
点击 RTSP实时监控项目：项目索引，回到目录。
协议实现过程：
1）创建TCP连接，与VLC客户端连接。
工作流程：创建tcp套接字，绑定端口，监听
2）解析客户端请求
客户端请求格式：
method url vesion\r\n
CSeq: x\r\n
xxx\r\n
...
\r\n
客户端的请求方法包括OPTIONS, DESCRIBE, SETUP, PLAY。。。
分析：首先我们先解析得到请求方法method，对于SETUP之外的方法，我们只解析CSeq；而对于SETUP，我们需要将client_port解析出来。
工作流程：sscanf解析第一行得到method，依次解析第二行得到CSeq，如果方法是SETUP则再解析得到RTP端口和RTCP端口。
3）对客户端请求进行响应
服务端响应格式：
vesion 200 OK\r\n
CSeq: x\r\n
...
\r\n
工作流程：根据不同method进行处理，将内容装载到封包，然后发送给客户端。
源代码
处理流程：
int rtsp_talk_with_client(int server_sockfd) {
// 创建SERVER_RTP和SERVER_RTCP端口的套接字
int rtp_fd = create_udp_socket();
int rtcp_fd = create_udp_socket();
if (rtp_fd < 0 || rtcp_fd < 0) {
printf("failed to create_udp_socket\n");
return -1;
}
if (bind_socket_addr(rtp_fd, "0.0.0.0", SERVER_RTP_PORT) < 0 || \
bind_socket_addr(rtcp_fd, "0.0.0.0", SERVER_RTCP_PORT) < 0) {
printf("failed to bind addr\n");
return -1;
}
int client_sockfd, client_port;
char client_ip[40];
while(1) {
client_sockfd = accept_client(server_sockfd, client_ip, &client_port);
if (client_sockfd < 0) {
printf("failed to accept client\n");
return -1;
}
printf("accept client: %s:%d\r\n", client_ip, client_port);
do_client(client_sockfd, client_ip, client_port, rtp_fd, rtcp_fd);
close_socket(client_sockfd);
}
close_socket(rtp_fd);
close_socket(rtcp_fd);
return 0;
}
int rtsp_test(void)
{
int server_sockfd = create_tcp_connect(SERVER_TCP_PORT);
if (server_sockfd < 0) return -1;
printf("rtsp://127.0.0.1:%d\n", SERVER_TCP_PORT);
rtsp_talk_with_client(server_sockfd);
close_socket(server_sockfd);
return 0;
}
解析请求并响应：
static char* getLineFromBuf(char* buf, char* line)
{
while(*buf != '\n') {
*line = *buf;
line++;
buf++;
}
*line = '\n'; ++line;
*line = '\0';
++buf;
return buf;
}
static void do_client(int clientSockfd, const char* clientIP, int clientPort,
int serverRtpSockfd, int serverRtcpSockfd)
{
char method[40], url[100], version[40];
int clientRtpPort, clientRtcpPort;
char *bufPtr;
char* rbuf = malloc(BUF_MAX_SIZE);
char* sbuf = malloc(BUF_MAX_SIZE);
char line[400];
int cseq = 0;
while(1)
{
int recvLen;
recvLen = recv(clientSockfd, rbuf, BUF_MAX_SIZE, 0);
if(recvLen <= 0)
goto out;
rbuf[recvLen] = '\0';
printf("---------------C->S--------------\n");
printf("%s", rbuf);
/* 解析方法 */
bufPtr = getLineFromBuf(rbuf, line);
if(sscanf(line, "%s %s %s\r\n", method, url, version) != 3)
{
printf("parse err\n");
goto out;
}
/* 解析序列号 */
bufPtr = getLineFromBuf(bufPtr, line);
if(sscanf(line, "CSeq: %d\r\n", &cseq) != 1)
{
printf("parse err\n");
goto out;
}
/* 如果是SETUP，那么就再解析client_port */
if(!strcmp(method, "SETUP"))
{
while(1)
{
bufPtr = getLineFromBuf(bufPtr, line);
if(!strncmp(line, "Transport:", strlen("Transport:")))
{
sscanf(line, "Transport: RTP/AVP;unicast;client_port=%d-%d\r\n",
&clientRtpPort, &clientRtcpPort);
break;
}
}
}
if(!strcmp(method, "OPTIONS"))
{
if(handleCmd_OPTIONS(sbuf, cseq))
{
printf("failed to handle options\n");
goto out;
}
}
else if(!strcmp(method, "DESCRIBE"))
{
if(handleCmd_DESCRIBE(sbuf, cseq, url))
{
printf("failed to handle describe\n");
goto out;
}
}
else if(!strcmp(method, "SETUP"))
{
if(handleCmd_SETUP(sbuf, cseq, clientRtpPort))
{
printf("failed to handle setup\n");
goto out;
}
}
else if(!strcmp(method, "PLAY"))
{
if(handleCmd_PLAY(sbuf, cseq))
{
printf("failed to handle play\n");
goto out;
}
}
else
{
goto out;
}
printf("---------------S->C--------------\n");
printf("%s", sbuf);
send(clientSockfd, sbuf, strlen(sbuf), 0);
}
out:
close_socket(clientSockfd);
free(rbuf);
free(sbuf);
}
封装响应数据包：
static int handleCmd_OPTIONS(char* result, int cseq)
{
sprintf(result, "RTSP/1.0 200 OK\r\n"
"CSeq: %d\r\n"
"Public: OPTIONS, DESCRIBE, SETUP, PLAY\r\n"
"\r\n",
cseq);
return 0;
}
static int handleCmd_DESCRIBE(char* result, int cseq, char* url)
{
char sdp[500];
char localIp[100];
sscanf(url, "rtsp://%[^:]:", localIp);
sprintf(sdp, "v=0\r\n"
"o=- 9%ld 1 IN IP4 %s\r\n"
"t=0 0\r\n"
"a=control:*\r\n"
"m=video 0 RTP/AVP 96\r\n"
"a=rtpmap:96 H264/90000\r\n"
"a=control:track0\r\n",
time(NULL), localIp);
sprintf(result, "RTSP/1.0 200 OK\r\nCSeq: %d\r\n"
"Content-Base: %s\r\n"
"Content-type: application/sdp\r\n"
"Content-length: %d\r\n\r\n"
"%s",
cseq,
url,
strlen(sdp),
sdp);
return 0;
}
static int handleCmd_SETUP(char* result, int cseq, int clientRtpPort)
{
sprintf(result, "RTSP/1.0 200 OK\r\n"
"CSeq: %d\r\n"
"Transport: RTP/AVP;unicast;client_port=%d-%d;server_port=%d-%d\r\n"
"Session: 66334873\r\n"
"\r\n",
cseq,
clientRtpPort,
clientRtpPort+1,
SERVER_RTP_PORT,
SERVER_RTCP_PORT);
return 0;
}
static int handleCmd_PLAY(char* result, int cseq)
{
sprintf(result, "RTSP/1.0 200 OK\r\n"
"CSeq: %d\r\n"
"Range: npt=0.000-\r\n"
"Session: 66334873; timeout=60\r\n\r\n",
cseq);
return 0;
}
rtsp协议代码例程（作者：JT）：https://blog.csdn.net/weixin_42462202/article/details/99068041
vlc客户端打开网络串流rtsp://192.168.174.3:1935/live
