Problem statement -- I am able to establish connection with broadcast IP 255.255.255.255 when both applications are in two different Linux machines. Linux Machine where server is running is replying when client broadcast-ed a message to the above mentioned address. But when I am porting client to FreeBSD machine. I am not able to get message at Linux server machine when I broadcast-ed a message from server (FreeBSD machine) to 255.255.255.255 Could you please help me what change I can do in the client/broadcaster source to make it compatible for FreeBSD machine too. You can find sample source code of server/listener and client/broadcaster as below --
Client/Broadcaster sample :
C:
/*
** listener.c -- a datagram sockets "server" demo
*/
#include <arpa/inet.h> // for inet_ntop
#include <netdb.h> // for addrinfo, freeaddrinfo, gai_strerror
#include <netinet/in.h> // for INET6_ADDRSTRLEN, sockaddr_in, sockadd...
#include <stdio.h> // for printf, fprintf, perror, NULL, stderr
#include <stdlib.h> // for exit
#include <string.h> // for memset
#include <sys/socket.h> // for sockaddr_storage, bind, socket, AF_INET
#include <unistd.h> // for close
#define MYPORT "4950" // the port users will be connecting to
#define MAXBUFLEN 100
// get sockaddr, IPv4 or IPv6:
static void *get_in_addr(struct sockaddr *sa) {
if (sa->sa_family == AF_INET) {
return &(((struct sockaddr_in *)sa)->sin_addr);
}
return &(((struct sockaddr_in6 *)sa)->sin6_addr);
}
int main(void) {
int sockfd;
struct addrinfo hints, *servinfo, *p;
int rv;
ssize_t numbytes;
struct sockaddr_storage their_addr;
char buf[MAXBUFLEN];
socklen_t addr_len;
char s[INET6_ADDRSTRLEN];
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC; // set to AF_INET to force IPv4
hints.ai_socktype = SOCK_DGRAM;
hints.ai_flags = AI_PASSIVE; // use my IP
if ((rv = getaddrinfo(NULL, MYPORT, &hints, &servinfo)) != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
return 1;
}
// loop through all the results and bind to the first we can
for (p = servinfo; p != NULL; p = p->ai_next) {
if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) ==
-1) {
perror("listener: socket");
continue;
}
if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
close(sockfd);
perror("listener: bind");
continue;
}
break;
}
freeaddrinfo(servinfo);
if (p == NULL) {
fprintf(stderr, "listener: failed to bind socket\n");
return 2;
}
printf("listener: waiting to recvfrom...\n");
addr_len = sizeof their_addr;
if ((numbytes = recvfrom(sockfd, buf, MAXBUFLEN - 1, 0,
(struct sockaddr *)&their_addr, &addr_len)) ==
-1) {
perror("recvfrom");
exit(1);
}
printf("listener: got packet from %s\n",
inet_ntop(their_addr.ss_family,
get_in_addr((struct sockaddr *)&their_addr), s, sizeof s));
printf("listener: packet is %ld bytes long\n", numbytes);
buf[numbytes] = '\0';
printf("listener: packet contains \"%s\"\n", buf);
close(sockfd);
return 0;
}Client/Broadcaster sample :
C:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#define SERVERPORT 4950 // the port users will be connecting to
int main(int argc, char *argv[])
{
int sockfd;
struct sockaddr_in their_addr; // connector's address information
struct hostent *he;
int numbytes;
int broadcast = 1;
//char broadcast = '1'; // if that doesn't work, try this
if (argc != 3) {
fprintf(stderr,"usage: broadcaster hostname message\n");
exit(1);
}
if ((he=gethostbyname(argv[1])) == NULL) { // get the host info
perror("gethostbyname");
exit(1);
}
if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
perror("socket");
exit(1);
}
// this call is what allows broadcast packets to be sent:
if (setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &broadcast,
sizeof broadcast) == -1) {
perror("setsockopt (SO_BROADCAST)");
exit(1);
}
their_addr.sin_family = AF_INET; // host byte order
their_addr.sin_port = htons(SERVERPORT); // short, network byte order
their_addr.sin_addr = *((struct in_addr *)he->h_addr);
memset(their_addr.sin_zero, '\0', sizeof their_addr.sin_zero);
if ((numbytes=sendto(sockfd, argv[2], strlen(argv[2]), 0,
(struct sockaddr *)&their_addr, sizeof their_addr)) == -1) {
perror("sendto");
exit(1);
}
printf("sent %d bytes to %s\n", numbytes,
inet_ntoa(their_addr.sin_addr));
close(sockfd);
return 0;
}