Commit | Line | Data |
---|---|---|
3415540f FT |
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> | |
b5038e15 FT |
7 | #include <arpa/inet.h> |
8 | #include <errno.h> | |
49697920 FT |
9 | #include <net/if.h> |
10 | #include <linux/if_tun.h> | |
11 | #include <fcntl.h> | |
12 | #include <sys/ioctl.h> | |
13 | #include <sys/poll.h> | |
b5038e15 FT |
14 | |
15 | #include "utils.h" | |
3415540f FT |
16 | |
17 | static void usage(FILE *out) | |
18 | { | |
49697920 | 19 | fprintf(out, "usage: mctap [-h] [-D TAPNAME] MCASTGROUP PORT\n"); |
b5038e15 FT |
20 | } |
21 | ||
49697920 | 22 | static __attribute__ ((unused)) char *formataddress(struct sockaddr *arg, socklen_t arglen) |
b5038e15 FT |
23 | { |
24 | struct sockaddr_in *ipv4; | |
25 | struct sockaddr_in6 *ipv6; | |
26 | static char *ret = NULL; | |
27 | char buf[1024]; | |
28 | ||
29 | if(ret != NULL) | |
30 | free(ret); | |
31 | ret = NULL; | |
32 | switch(arg->sa_family) | |
33 | { | |
34 | case AF_UNIX: | |
49697920 | 35 | ret = sstrdup("Unix socket"); |
b5038e15 FT |
36 | break; |
37 | case AF_INET: | |
38 | ipv4 = (struct sockaddr_in *)arg; | |
39 | if(inet_ntop(AF_INET, &ipv4->sin_addr, buf, sizeof(buf)) == NULL) | |
40 | return(NULL); | |
41 | ret = sprintf2("%s:%i", buf, (int)ntohs(ipv4->sin_port)); | |
42 | break; | |
43 | case AF_INET6: | |
44 | ipv6 = (struct sockaddr_in6 *)arg; | |
45 | if(inet_ntop(AF_INET6, &ipv6->sin6_addr, buf, sizeof(buf)) == NULL) | |
46 | return(NULL); | |
47 | ret = sprintf2("[%s]:%i", buf, (int)ntohs(ipv6->sin6_port)); | |
48 | break; | |
49 | default: | |
50 | errno = EPFNOSUPPORT; | |
51 | break; | |
52 | } | |
53 | return(ret); | |
54 | } | |
55 | ||
56 | static int mkmcastsk4(struct in_addr group, int port) | |
57 | { | |
58 | int fd; | |
aeddd223 | 59 | int soval; |
b5038e15 FT |
60 | struct sockaddr_in nm; |
61 | struct ip_mreqn mreq; | |
62 | ||
63 | fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); | |
aeddd223 FT |
64 | soval = 1; |
65 | if(setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &soval, sizeof(soval))) | |
66 | return(-1); | |
b5038e15 FT |
67 | memset(&nm, 0, sizeof(nm)); |
68 | nm.sin_family = AF_INET; | |
69 | nm.sin_port = htons(port); | |
70 | if(bind(fd, (struct sockaddr *)&nm, sizeof(nm))) | |
71 | return(-1); | |
72 | memset(&mreq, 0, sizeof(mreq)); | |
73 | mreq.imr_multiaddr = group; | |
aeddd223 | 74 | if(setsockopt(fd, SOL_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq))) |
b5038e15 | 75 | return(-1); |
af3fc4a5 FT |
76 | soval = 1; |
77 | if(setsockopt(fd, SOL_IP, IP_MULTICAST_LOOP, &soval, sizeof(soval))) | |
78 | return(-1); | |
b5038e15 FT |
79 | return(fd); |
80 | } | |
81 | ||
49697920 | 82 | static __attribute__ ((unused)) void test(int fd) |
b5038e15 FT |
83 | { |
84 | char buf[65536]; | |
4f6c7408 | 85 | int i, ret; |
49697920 | 86 | struct pollfd pfd; |
b5038e15 FT |
87 | |
88 | while(1) { | |
49697920 FT |
89 | pfd.fd = fd; |
90 | pfd.events = POLLIN; | |
91 | ret = poll(&pfd, 1, -1); | |
b5038e15 | 92 | if(ret < 0) { |
49697920 | 93 | fprintf(stderr, "mctap: poll: %s\n", strerror(errno)); |
b5038e15 FT |
94 | exit(1); |
95 | } | |
49697920 FT |
96 | if(pfd.revents) { |
97 | ret = read(fd, buf, sizeof(buf)); | |
98 | if(ret < 0) { | |
99 | fprintf(stderr, "mctap: read: %s\n", strerror(errno)); | |
100 | exit(1); | |
101 | } | |
102 | for(i = 0; i < ret; i++) { | |
103 | printf("%02x ", (unsigned char)buf[i]); | |
104 | if(i % 20 == 19) | |
105 | putchar(10); | |
106 | } | |
107 | putchar(10); | |
4f6c7408 | 108 | } |
b5038e15 | 109 | } |
3415540f FT |
110 | } |
111 | ||
49697920 FT |
112 | static void bridge(int sock, int tap, struct sockaddr *dst, socklen_t dstlen) |
113 | { | |
114 | char buf[65536]; | |
115 | int ret; | |
116 | struct pollfd pfds[2]; | |
117 | struct tun_pi pi; | |
118 | ||
119 | fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) | O_NONBLOCK); | |
120 | fcntl(tap, F_SETFL, fcntl(tap, F_GETFL) | O_NONBLOCK); | |
121 | while(1) { | |
122 | pfds[0].fd = sock; | |
123 | pfds[0].events = POLLIN; | |
124 | pfds[1].fd = tap; | |
125 | pfds[1].events = POLLIN; | |
126 | ret = poll(pfds, 2, -1); | |
127 | if(ret < 0) { | |
128 | if(errno != EINTR) { | |
129 | fprintf(stderr, "mctap: poll: %s\n", strerror(errno)); | |
130 | exit(1); | |
131 | } | |
132 | continue; | |
133 | } | |
134 | if(pfds[0].revents) { | |
135 | ret = read(sock, buf, sizeof(buf)); | |
136 | if(ret < 0) { | |
137 | if((errno != EINTR) && (errno != EAGAIN)) { | |
138 | fprintf(stderr, "mctap: mcast packet: %s\n", strerror(errno)); | |
139 | exit(1); | |
140 | } | |
141 | } else { | |
142 | if(sizeof(buf) - ret < sizeof(pi)) { | |
143 | /* Drop */ | |
144 | } else { | |
145 | memmove(buf + sizeof(pi), buf, ret); | |
146 | pi.flags = 0; | |
147 | pi.proto = 0; | |
148 | memcpy(buf, &pi, sizeof(pi)); | |
3cb771e8 | 149 | write(tap, buf, sizeof(pi) + ret); |
49697920 FT |
150 | } |
151 | } | |
152 | } | |
153 | if(pfds[1].revents) { | |
154 | ret = read(tap, buf, sizeof(buf)); | |
155 | if(ret < 0) { | |
156 | if((errno != EINTR) && (errno != EAGAIN)) { | |
157 | fprintf(stderr, "mctap: mcast packet: %s\n", strerror(errno)); | |
158 | exit(1); | |
159 | } | |
160 | } else { | |
161 | if(ret < sizeof(pi)) { | |
162 | /* Drop */ | |
163 | } else { | |
164 | memcpy(&pi, buf, sizeof(pi)); | |
165 | if(pi.flags & TUN_PKT_STRIP) { | |
166 | /* Drop */ | |
167 | } else { | |
168 | sendto(sock, buf + sizeof(pi), ret - sizeof(pi), 0, dst, dstlen); | |
169 | } | |
170 | } | |
171 | } | |
172 | } | |
173 | } | |
174 | } | |
175 | ||
176 | static int maketap(char *name) | |
177 | { | |
178 | int fd; | |
179 | struct ifreq rb; | |
180 | ||
181 | if((fd = open("/dev/net/tun", O_RDWR)) < 0) | |
182 | return(-1); | |
183 | memset(&rb, 0, sizeof(rb)); | |
184 | rb.ifr_flags = IFF_TAP; | |
185 | strncpy(rb.ifr_name, name, IFNAMSIZ); | |
186 | if(ioctl(fd, TUNSETIFF, &rb)) | |
187 | return(-1); | |
188 | return(fd); | |
189 | } | |
190 | ||
3415540f FT |
191 | int main(int argc, char **argv) |
192 | { | |
193 | int c; | |
49697920 | 194 | int sock, tap; |
b5038e15 FT |
195 | struct in_addr group; |
196 | int port; | |
49697920 FT |
197 | char *tapname; |
198 | struct sockaddr_in dst; | |
3415540f | 199 | |
49697920 FT |
200 | tapname = "mctap"; |
201 | while((c = getopt(argc, argv, "hD:")) >= 0) { | |
3415540f | 202 | switch(c) { |
49697920 FT |
203 | case 'D': |
204 | tapname = optarg; | |
205 | break; | |
3415540f FT |
206 | case 'h': |
207 | usage(stdout); | |
208 | return(0); | |
209 | default: | |
210 | usage(stderr); | |
211 | exit(1); | |
212 | } | |
213 | } | |
b5038e15 FT |
214 | if(argc - optind < 2) { |
215 | usage(stderr); | |
216 | exit(1); | |
217 | } | |
218 | if(!inet_aton(argv[optind], &group)) { | |
219 | fprintf(stderr, "mctap: invalid group address: %s\n", argv[optind]); | |
220 | exit(1); | |
221 | } | |
222 | port = atoi(argv[optind + 1]); | |
223 | if((sock = mkmcastsk4(group, port)) < 0) { | |
224 | fprintf(stderr, "mctap: could not create multicast socket: %s\n", strerror(errno)); | |
225 | exit(1); | |
226 | } | |
49697920 FT |
227 | if((tap = maketap(tapname)) < 0) { |
228 | fprintf(stderr, "mctap: could not create TAP device: %s\n", strerror(errno)); | |
229 | exit(1); | |
230 | } | |
3415540f | 231 | |
49697920 FT |
232 | memset(&dst, 0, sizeof(dst)); |
233 | dst.sin_family = AF_INET; | |
234 | dst.sin_addr = group; | |
235 | dst.sin_port = htons(port); | |
236 | bridge(sock, tap, (struct sockaddr *)&dst, sizeof(dst)); | |
3415540f FT |
237 | return(0); |
238 | } |