c - 基于sctp套接字的c中服务器客户端程序

问题描述

我已经用 sctp 协议编写了这个服务器-客户端程序。当我在本地机器上以环回 IP 作为目标运行这个程序时，这个程序可以正常工作。但是当我在两个不同的远程系统中运行服务器和客户端代码时，代码不起作用。

sctp_sendmsg 函数需要太多发送，当发送成功时，我在服务器上看不到任何消息。

    /*
 * Compile:
 *
 *   gcc sctp.c -o server -lsctp -Wall
 *   ln -s server client
 *
 * Invoke:
 *
 *   ./client
 *   ./server
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libgen.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netinet/sctp.h>
#include <arpa/inet.h>

#define MY_PORT_NUM 21233

static void die(const char *s) {
        perror(s);
        exit(1);
}

static void server(void) {
        int listen_fd, conn_fd, flags, ret, in;
        struct sctp_sndrcvinfo sndrcvinfo;
        struct sockaddr_in servaddr = {
                .sin_family = AF_INET,
                .sin_addr.s_addr = htonl(INADDR_ANY),
                .sin_port = htons(MY_PORT_NUM),
        };
        struct sockaddr_in client_addr;
        socklen_t clilen=sizeof(client_addr);
        struct sctp_initmsg initmsg = {
                .sinit_num_ostreams = 5,
                .sinit_max_instreams = 5,
                .sinit_max_attempts = 4,
        };

        listen_fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (listen_fd < 0)
                die("socket");

        ret = bind(listen_fd, (struct sockaddr *) &servaddr, sizeof(servaddr));
        if (ret < 0)
                die("bind");


        ret = listen(listen_fd, initmsg.sinit_max_instreams);
        if (ret < 0)
                die("listen");

        for (;;) {
                char buffer[1024];

                printf("Waiting for connection\n");

                in = sctp_recvmsg(listen_fd, buffer, sizeof(buffer),(struct sockaddr*)&client_addr,&clilen,0,0);
                printf("%d\n",in);
                    if (in > 0) {
                            printf("Received data: %s\n", buffer);
                            fflush(stdout);
                    }
        }
        close(listen_fd);
}

static void client(void) {
        int conn_fd, ret;
        const char *msg = "Hello, Server!";
        struct sockaddr_in servaddr = {
                .sin_family = AF_INET,
                .sin_port = htons(MY_PORT_NUM),
                .sin_addr.s_addr = inet_addr("45.125.222.112"),
        };

        conn_fd = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);
        if (conn_fd < 0)
                die("socket()");

        struct sctp_initmsg initmsg = {
                .sinit_num_ostreams = 5,
                .sinit_max_instreams = 5,
                .sinit_max_attempts = 4,
        };

        setsockopt(conn_fd, IPPROTO_SCTP, SCTP_INITMSG, &initmsg, sizeof(initmsg));
        int i;
        for(i=0;i<4;i++){
            printf("before sending\n");
            ret = sctp_sendmsg(conn_fd, (void *) msg, strlen(msg) + 1,(struct sockaddr*)&servaddr,sizeof(struct sockaddr),0,0,0,0,0);
            printf("after sending\n");
            if (ret < 0)
                    printf("failed to send %d\n",i);
            else 
                printf("success %d\n",i);

        }
        close(conn_fd);

}

int main(int argc, char **argv) {

        if (strstr(basename(argv[0]), "server"))
                server();
        else
                client();

        return 0;
}

标签： csocketssctp

c - 基于sctp套接字的c中服务器客户端程序

问题描述

解决方案

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