We are trying UDP multicast with follwoing sender & receiver codes. We are unable to receive when we send from any PC
Also find binaries atatched, We are trying the Sender on X86 PC & receiver on IMX27 ADS board
We don't get any error as such, it just don't receive the packets
******************************Receiver************************************#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #define MAX_LEN 1024int main(int argc, char *argv[]){ int sock; int flag_on = 1; struct sockaddr_in multicast_addr; char message_received[MAX_LEN+1]; int msgrecv_len; struct ip_mreq mc_req; char* multicast_ip; unsigned short multicast_port; struct sockaddr_in from_addr; unsigned int from_len; if (argc != 3) { fprintf(stderr, "Usage: %s Multicast_IP Multicast_Port\n", argv[0]); exit(1); } multicast_ip = argv[1]; /* arg 1: multicast ip address */ multicast_port = atoi(argv[2]); /* arg 2: multicast port number */ if ((sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) { perror("socket() failed"); exit(1); } /* set reuse port to on to allow multiple binds per host */ if ((setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &flag_on, sizeof(flag_on))) < 0) { perror("setsockopt() failed"); exit(1); } /* construct a multicast address structure */ memset(&multicast_addr, 0, sizeof(multicast_addr)); multicast_addr.sin_family = AF_INET; multicast_addr.sin_addr.s_addr = htonl(INADDR_ANY); multicast_addr.sin_port = htons(multicast_port); /* bind to multicast address to socket */ if ((bind(sock, (struct sockaddr *) &multicast_addr, sizeof(multicast_addr))) < 0) { perror("bind() failed"); exit(1); } /* construct an IGMP join request structure */ mc_req.imr_multiaddr.s_addr = inet_addr(multicast_ip); mc_req.imr_interface.s_addr = htonl(INADDR_ANY); /* send an ADD MEMBERSHIP message via setsockopt */ if ((setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (void*) &mc_req, sizeof(mc_req))) < 0) { perror("setsockopt() failed"); exit(1); } while(1) { memset(message_received, 0, sizeof(message_received)); from_len = sizeof(from_addr); memset(&from_addr, 0, from_len); /* block waiting to receive a packet */ if ((msgrecv_len = recvfrom(sock, message_received, MAX_LEN, 0, (struct sockaddr*)&from_addr, &from_len)) < 0) { perror("recvfrom() failed"); break; } printf("Received %d bytes from %s: ", msgrecv_len, inet_ntoa(from_addr.sin_addr)); printf("%s", message_received); } /* send a DROP MEMBERSHIP message via setsockopt */ if ((setsockopt(sock, IPPROTO_IP, IP_DROP_MEMBERSHIP, (void*) &mc_req, sizeof(mc_req))) < 0) { perror("setsockopt() failed"); exit(1); } close(sock);}***************************Receiver END*************************************************************Sender***********************#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #define MAX_LEN 1024 int main(int argc, char *argv[]){ int sock; char message_to_send[MAX_LEN]; unsigned int send_len; char* multicast_ip; unsigned short multicast_port; unsigned char multicast_ttl=1; struct sockaddr_in multicast_addr; if (argc != 3) { fprintf(stderr, "Usage: %s Multicast_IP Multicast_Port\n", argv[0]); exit(1); } multicast_ip = argv[1]; /* arg 1: multicast IP address */ multicast_port = atoi(argv[2]); /* arg 2: multicast port number */ /* create a socket */ if ((sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) { perror("Socket creation failed"); exit(1); } /* set the TTL (time to live/hop count) for(i=0;i<5;i++){} the send */ if ((setsockopt(sock, IPPROTO_IP, IP_MULTICAST_TTL, (void*) &multicast_ttl, sizeof(multicast_ttl))) < 0) { perror("setsockopt() failed"); exit(1); } memset(&multicast_addr, 0, sizeof(multicast_addr)); multicast_addr.sin_family = AF_INET; multicast_addr.sin_addr.s_addr = inet_addr(multicast_ip); multicast_addr.sin_port = htons(multicast_port); printf("Type the message below (Press Enter to send, ctrl-C to quit):\n"); memset(message_to_send, 0, sizeof(message_to_send)); while(fgets(message_to_send, MAX_LEN, stdin)) { send_len = strlen(message_to_send); if ((sendto(sock, message_to_send, send_len, 0, (struct sockaddr *) &multicast_addr, sizeof(multicast_addr))) != send_len) { perror("Error include<> number of bytes"); exit(1); } memset(message_to_send, 0, sizeof(message_to_send)); } close(sock); exit(0);}*************************************Receiver END
Please note that this code works fine when we enable the external controller on the IMX27 ADS board.