mongoose/examples/mcast_udp_server/mcast_udp_server.c
Dmitry Frank e5b3b8ad32 Ensure not to overflow buf in udp server example
PUBLISHED_FROM=413f5073b0fc267d66ce04d8d40e9e9d7abac94d
2018-01-30 20:39:50 +00:00

108 lines
2.9 KiB
C

// Copyright (c) 2016 Cesanta Software Limited
// All rights reserved
//
// This software is dual-licensed: you can redistribute it and/or modify
// it under the terms of the GNU General Public License version 2 as
// published by the Free Software Foundation. For the terms of this
// license, see <http://www.gnu.org/licenses/>.
//
// You are free to use this software under the terms of the GNU General
// Public License, but WITHOUT ANY WARRANTY; without even the implied
// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License for more details.
//
// Alternatively, you can license this software under a commercial
// license, as set out in <https://www.cesanta.com/license>.
//
// This demo shows how to configure a mongoose UDP connection to receive
// multicast traffic.
#include <netinet/in.h>
#include "mongoose.h"
#define MCAST_GROUP "224.0.22.1"
#define DEFAULT_PORT "1234"
static void ev_handler(struct mg_connection *nc, int ev, void *p) {
struct mbuf *io = &nc->recv_mbuf;
(void) p;
switch (ev) {
case MG_EV_POLL: {
const char *peer;
peer = inet_ntoa(nc->sa.sin.sin_addr);
printf("nc->sa: %s %d\n", peer, ntohs(nc->sa.sin.sin_port));
break;
}
case MG_EV_RECV:
printf("Received (%zu bytes): '%.*s'\n", io->len, (int) io->len, io->buf);
mbuf_remove(io, io->len);
nc->flags |= MG_F_SEND_AND_CLOSE;
break;
default:
break;
}
}
void usage(char **argv) {
fprintf(stderr, "%s: -i address_of_mcast_interface [ -g %s ] [ -p %s ]\n",
argv[0], MCAST_GROUP, DEFAULT_PORT);
exit(1);
}
int main(int argc, char **argv) {
struct mg_mgr mgr;
const char *port = "1234";
struct mg_connection *nc;
struct ip_mreq group;
const char *interface = NULL;
const char *mcast_group = MCAST_GROUP;
int i;
/* Parse command line arguments */
for (i = 1; i < argc; i++) {
// IP address of the interface where to join a multicast group.
if (strcmp(argv[i], "-i") == 0) {
interface = argv[++i];
} else if (strcmp(argv[i], "-g") == 0) {
mcast_group = argv[++i];
} else if (strcmp(argv[i], "-p") == 0) {
port = argv[++i];
}
}
if (interface == NULL) {
usage(argv);
}
mg_mgr_init(&mgr, NULL);
{
char listen[256];
snprintf(listen, sizeof(listen), "udp://%s", port);
nc = mg_bind(&mgr, listen, ev_handler);
}
if (nc == NULL) {
perror("cannot bind\n");
exit(1);
}
group.imr_multiaddr.s_addr = inet_addr(mcast_group);
group.imr_interface.s_addr = inet_addr(interface);
if (setsockopt(nc->sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *) &group,
sizeof(group)) < 0) {
perror("Adding multicast group error");
exit(1);
}
printf("Starting mcast server on port %s listening to group %s\n", port,
mcast_group);
for (;;) {
mg_mgr_poll(&mgr, 1000);
}
mg_mgr_free(&mgr);
return 0;
}