| 1 | #include <stdlib.h> |
| 2 | #include <stdio.h> |
| 3 | #include <string.h> |
| 4 | #include <unistd.h> |
| 5 | #include <sys/socket.h> |
| 6 | #include <netinet/in.h> |
| 7 | #include <arpa/inet.h> |
| 8 | #include <errno.h> |
| 9 | |
| 10 | #include "utils.h" |
| 11 | |
| 12 | static void usage(FILE *out) |
| 13 | { |
| 14 | fprintf(out, "usage: mctap [-h] MCASTGROUP PORT\n"); |
| 15 | } |
| 16 | |
| 17 | static char *formataddress(struct sockaddr *arg, socklen_t arglen) |
| 18 | { |
| 19 | struct sockaddr_in *ipv4; |
| 20 | struct sockaddr_in6 *ipv6; |
| 21 | static char *ret = NULL; |
| 22 | char buf[1024]; |
| 23 | |
| 24 | if(ret != NULL) |
| 25 | free(ret); |
| 26 | ret = NULL; |
| 27 | switch(arg->sa_family) |
| 28 | { |
| 29 | case AF_UNIX: |
| 30 | ret = strdup("Unix socket"); |
| 31 | break; |
| 32 | case AF_INET: |
| 33 | ipv4 = (struct sockaddr_in *)arg; |
| 34 | if(inet_ntop(AF_INET, &ipv4->sin_addr, buf, sizeof(buf)) == NULL) |
| 35 | return(NULL); |
| 36 | ret = sprintf2("%s:%i", buf, (int)ntohs(ipv4->sin_port)); |
| 37 | break; |
| 38 | case AF_INET6: |
| 39 | ipv6 = (struct sockaddr_in6 *)arg; |
| 40 | if(inet_ntop(AF_INET6, &ipv6->sin6_addr, buf, sizeof(buf)) == NULL) |
| 41 | return(NULL); |
| 42 | ret = sprintf2("[%s]:%i", buf, (int)ntohs(ipv6->sin6_port)); |
| 43 | break; |
| 44 | default: |
| 45 | errno = EPFNOSUPPORT; |
| 46 | break; |
| 47 | } |
| 48 | return(ret); |
| 49 | } |
| 50 | |
| 51 | static int mkmcastsk4(struct in_addr group, int port) |
| 52 | { |
| 53 | int fd; |
| 54 | int soval; |
| 55 | struct sockaddr_in nm; |
| 56 | struct ip_mreqn mreq; |
| 57 | |
| 58 | fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); |
| 59 | soval = 1; |
| 60 | if(setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &soval, sizeof(soval))) |
| 61 | return(-1); |
| 62 | memset(&nm, 0, sizeof(nm)); |
| 63 | nm.sin_family = AF_INET; |
| 64 | nm.sin_port = htons(port); |
| 65 | if(bind(fd, (struct sockaddr *)&nm, sizeof(nm))) |
| 66 | return(-1); |
| 67 | memset(&mreq, 0, sizeof(mreq)); |
| 68 | mreq.imr_multiaddr = group; |
| 69 | if(setsockopt(fd, SOL_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq))) |
| 70 | return(-1); |
| 71 | soval = 1; |
| 72 | if(setsockopt(fd, SOL_IP, IP_MULTICAST_LOOP, &soval, sizeof(soval))) |
| 73 | return(-1); |
| 74 | return(fd); |
| 75 | } |
| 76 | |
| 77 | static void test(int fd) |
| 78 | { |
| 79 | char buf[65536]; |
| 80 | int ret; |
| 81 | struct sockaddr_storage nm; |
| 82 | socklen_t nmlen; |
| 83 | |
| 84 | while(1) { |
| 85 | nmlen = sizeof(nm); |
| 86 | ret = recvfrom(fd, buf, sizeof(buf), 0, (struct sockaddr *)&nm, &nmlen); |
| 87 | if(ret < 0) { |
| 88 | fprintf(stderr, "mctap: recvfrom: %s\n", strerror(ret)); |
| 89 | exit(1); |
| 90 | } |
| 91 | printf("%s %i:\n", formataddress((struct sockaddr *)&nm, nmlen), ret); |
| 92 | } |
| 93 | } |
| 94 | |
| 95 | int main(int argc, char **argv) |
| 96 | { |
| 97 | int c; |
| 98 | int sock; |
| 99 | struct in_addr group; |
| 100 | int port; |
| 101 | |
| 102 | while((c = getopt(argc, argv, "h")) >= 0) { |
| 103 | switch(c) { |
| 104 | case 'h': |
| 105 | usage(stdout); |
| 106 | return(0); |
| 107 | default: |
| 108 | usage(stderr); |
| 109 | exit(1); |
| 110 | } |
| 111 | } |
| 112 | if(argc - optind < 2) { |
| 113 | usage(stderr); |
| 114 | exit(1); |
| 115 | } |
| 116 | if(!inet_aton(argv[optind], &group)) { |
| 117 | fprintf(stderr, "mctap: invalid group address: %s\n", argv[optind]); |
| 118 | exit(1); |
| 119 | } |
| 120 | port = atoi(argv[optind + 1]); |
| 121 | if((sock = mkmcastsk4(group, port)) < 0) { |
| 122 | fprintf(stderr, "mctap: could not create multicast socket: %s\n", strerror(errno)); |
| 123 | exit(1); |
| 124 | } |
| 125 | |
| 126 | test(sock); |
| 127 | return(0); |
| 128 | } |