Simple client/server test for SCTP

sctptest.c

/*
 * Compile:
 *
 *   gcc sctptest.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 62324

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

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

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

        ret = setsockopt(listen_fd, IPPROTO_SCTP, SCTP_INITMSG, &initmsg, sizeof(initmsg));
        if (ret < 0)
                die("setsockopt");

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

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

                printf("Waiting for connection\n");
                fflush(stdout);

                conn_fd = accept(listen_fd, (struct sockaddr *) NULL, NULL);
                if(conn_fd < 0)
                        die("accept()");

                printf("New client connected\n");
                fflush(stdout);

                in = sctp_recvmsg(conn_fd, buffer, sizeof(buffer), NULL, 0, &sndrcvinfo, &flags);
                if (in > 0) {
                        printf("Received data: %s\n", buffer);
                        fflush(stdout);
                }

                close(conn_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("127.0.0.1"),
        };

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

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

        ret = sctp_sendmsg(conn_fd, (void *) msg, strlen(msg) + 1, NULL, 0, 0, 0, 0, 0, 0 );
        if (ret < 0)
                die("sctp_sendmsg");

        close(conn_fd);
}

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

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

        return 0;
}

Good code!!!

A small suggestion about the notes at the beginning.
First to run server then client. Otherwise, it will fail.
/*

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

Yes, that's what the comment suggests already?

…

On November 26, 2020 6:54:41 AM GMT+01:00, QinLongFei ***@***.***> wrote: Good code!!! A small suggestion about the notes at the beginning. First to run server then client. Otherwise, it will fail. /* * Compile: * * gcc sctptest.c -o server -lsctp -Wall * ln -s server client * * Invoke: * * ./server * ./client */

-- Sent from my mobile. Please excuse typos and brevity.

Is there any example of the other way around where the client is pulling data?

Does any of you know a public-facing server that can be used to test SCTP connections?