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3d6143ec DC |
1 | /* |
2 | * idnlookup - ICMP Domain Name lookup utility for Linux | |
3 | * Copyright (C) 2005 Fredrik Tolf <fredrik@dolda2000.com> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
18 | */ | |
51a62941 DC |
19 | #include <stdlib.h> |
20 | #include <unistd.h> | |
21 | #include <stdio.h> | |
22 | #include <string.h> | |
23 | #include <errno.h> | |
3d6143ec | 24 | #include <netdb.h> |
51a62941 DC |
25 | #include <sys/socket.h> |
26 | #include <netinet/in.h> | |
3d6143ec | 27 | #include <netinet/ip.h> |
51a62941 DC |
28 | #include <arpa/inet.h> |
29 | #include <sys/types.h> | |
3d6143ec DC |
30 | #include <sys/poll.h> |
31 | #include <sys/time.h> | |
51a62941 DC |
32 | |
33 | struct icmphdr { | |
34 | u_int8_t type; | |
35 | u_int8_t code; | |
36 | u_int16_t checksum; | |
3d6143ec DC |
37 | }; |
38 | ||
39 | struct reqhdr { | |
40 | u_int8_t type; | |
41 | u_int8_t code; | |
42 | u_int16_t checksum; | |
43 | u_int16_t id; | |
44 | u_int16_t seq; | |
45 | }; | |
46 | ||
47 | struct rephdr { | |
48 | u_int8_t type; | |
49 | u_int8_t code; | |
50 | u_int16_t checksum; | |
51a62941 DC |
51 | u_int16_t id; |
52 | u_int16_t seq; | |
3d6143ec DC |
53 | int32_t ttl; |
54 | ||
51a62941 DC |
55 | }; |
56 | ||
57 | #define ICMP_NAMEREQ 37 | |
58 | #define ICMP_NAMEREP 38 | |
59 | ||
3d6143ec DC |
60 | unsigned char buf[65536]; |
61 | ||
62 | /* DN decompression not yet implemented, since I don't know where to | |
63 | * begin counting the offset from -- the beginning of the ICMP | |
64 | * payload, or from the beginning of the DN data buffer? */ | |
65 | void printdn(FILE *f, unsigned char *dnbuf, size_t size) | |
66 | { | |
67 | unsigned char *p; | |
68 | ||
69 | p = dnbuf; | |
70 | while(p - dnbuf < size) { | |
71 | while(*p != 0) { | |
72 | if(*p & 0xc0) { | |
73 | fprintf(stderr, "domain name decompression not implemented, aborting\n"); | |
74 | exit(1); | |
75 | } | |
bfd59ca0 | 76 | fprintf(f, "%.*s", (int)*p, p + 1); |
3d6143ec | 77 | p += 1 + (int)*p; |
bfd59ca0 DC |
78 | if(*p != 0) |
79 | fprintf(f, "."); | |
3d6143ec DC |
80 | } |
81 | p++; | |
bfd59ca0 | 82 | fprintf(f, "\n"); |
3d6143ec DC |
83 | } |
84 | } | |
85 | ||
86 | void cksum(void *hdr, size_t len) | |
87 | { | |
88 | struct icmphdr *ih; | |
89 | u_int8_t *cb; | |
90 | int i; | |
9cc7607e | 91 | int b1, b2; |
3d6143ec DC |
92 | |
93 | ih = (struct icmphdr *)hdr; | |
94 | cb = (u_int8_t *)hdr; | |
95 | ih->checksum = 0; | |
96 | b1 = b2 = 0; | |
97 | for(i = 0; i < (len & ~1); i += 2) { | |
98 | b1 += cb[i]; | |
99 | b2 += cb[i + 1]; | |
100 | } | |
101 | if(i & 1) | |
102 | b1 += cb[len - 1]; | |
9cc7607e DC |
103 | while(1) { |
104 | if(b1 >= 256) { | |
105 | b2 += b1 >> 8; | |
106 | b1 &= 0xff; | |
107 | continue; | |
108 | } | |
109 | if(b2 >= 256) { | |
110 | b1 += b2 >> 8; | |
111 | b2 &= 0xff; | |
112 | continue; | |
113 | } | |
114 | break; | |
115 | } | |
3d6143ec | 116 | cb = (u_int8_t *)&ih->checksum; |
9cc7607e DC |
117 | cb[0] = ~(u_int8_t)b1; |
118 | cb[1] = ~(u_int8_t)b2; | |
3d6143ec DC |
119 | } |
120 | ||
121 | void usage(void) | |
122 | { | |
123 | fprintf(stderr, "usage: idnlookup [-h] [-t timeout] host\n"); | |
124 | } | |
125 | ||
51a62941 DC |
126 | int main(int argc, char **argv) |
127 | { | |
128 | int ret; | |
3d6143ec DC |
129 | int s, c; |
130 | int id; | |
131 | int namelen; | |
132 | struct reqhdr req; | |
133 | struct rephdr rep; | |
134 | struct iphdr iphdr; | |
135 | struct addrinfo *ai, *cai, aihint; | |
136 | struct pollfd pfd; | |
137 | struct timeval tvb, tvc; | |
138 | struct sockaddr_storage name; | |
139 | int timeout, elapsed; | |
51a62941 | 140 | |
3d6143ec DC |
141 | timeout = 3000; |
142 | while((c = getopt(argc, argv, "ht:")) != -1) { | |
143 | switch(c) { | |
144 | case 't': | |
145 | timeout = atoi(optarg); | |
146 | break; | |
147 | case 'h': | |
148 | case '?': | |
149 | case ':': | |
150 | default: | |
151 | usage(); | |
152 | exit((c == 'h')?0:1); | |
153 | } | |
51a62941 DC |
154 | } |
155 | ||
3d6143ec DC |
156 | if(argc - optind < 1) { |
157 | usage(); | |
158 | exit(1); | |
159 | } | |
51a62941 | 160 | |
3d6143ec DC |
161 | memset(&aihint, 0, sizeof(aihint)); |
162 | aihint.ai_family = PF_INET; /* Only IPv4 for now. */ | |
163 | aihint.ai_socktype = SOCK_RAW; | |
164 | aihint.ai_protocol = IPPROTO_ICMP; | |
165 | ret = getaddrinfo(argv[optind], NULL, &aihint, &ai); | |
51a62941 | 166 | |
3d6143ec DC |
167 | for(cai = ai; cai != NULL; cai = cai->ai_next) { |
168 | if((s = socket(cai->ai_family, SOCK_RAW, IPPROTO_ICMP)) < 0) { | |
169 | perror("could not create raw socket"); | |
170 | exit(1); | |
171 | } | |
172 | ||
173 | id = random() % 65536; | |
174 | memset(&req, 0, sizeof(req)); | |
175 | req.type = ICMP_NAMEREQ; | |
176 | req.id = htons(id); | |
177 | cksum(&req, sizeof(req)); | |
178 | ||
179 | ret = sendto(s, &req, sizeof(req), 0, cai->ai_addr, cai->ai_addrlen); | |
180 | if(ret < 0) { | |
181 | perror("sendto"); | |
182 | exit(1); | |
183 | } else if(ret != sizeof(req)) { | |
184 | fprintf(stderr, "socket would not send entire packet\n"); | |
185 | exit(1); | |
186 | } | |
187 | ||
188 | gettimeofday(&tvb, NULL); | |
189 | while(1) { | |
190 | pfd.fd = s; | |
191 | pfd.events = POLLIN; | |
192 | gettimeofday(&tvc, NULL); | |
193 | elapsed = ((tvc.tv_sec - tvb.tv_sec) * 1000) + ((tvc.tv_usec - tvb.tv_usec) / 1000); | |
194 | if(elapsed > timeout) { | |
195 | fprintf(stderr, "idnlookup: timeout\n"); | |
196 | exit(1); | |
197 | } | |
198 | ret = poll(&pfd, 1, timeout - elapsed); | |
199 | if(ret < 0) { | |
200 | perror("idnlookup: reading data"); | |
201 | exit(1); | |
202 | } | |
203 | ||
204 | if(pfd.revents & POLLIN) { | |
205 | namelen = sizeof(name); | |
206 | ret = recvfrom(s, buf, sizeof(buf), 0, (struct sockaddr *)&name, &namelen); | |
207 | if(ret < 0) { | |
208 | perror("idnlookup: receiving data"); | |
209 | exit(1); | |
210 | } | |
211 | ||
212 | if(name.ss_family != cai->ai_addr->sa_family) | |
213 | continue; | |
214 | if(name.ss_family == AF_INET) { | |
215 | if(memcmp(&(((struct sockaddr_in *)&name)->sin_addr), &(((struct sockaddr_in *)cai->ai_addr)->sin_addr), sizeof(struct in_addr))) | |
216 | continue; | |
217 | } else if(name.ss_family == AF_INET6) { | |
218 | if(memcmp(&(((struct sockaddr_in6 *)&name)->sin6_addr), &(((struct sockaddr_in6 *)cai->ai_addr)->sin6_addr), sizeof(struct in6_addr))) | |
219 | continue; | |
220 | } else { | |
221 | continue; | |
222 | } | |
223 | ||
224 | if(ret < sizeof(iphdr) + sizeof(rep)) | |
225 | continue; | |
226 | memcpy(&iphdr, buf, sizeof(iphdr)); | |
227 | memcpy(&rep, buf + sizeof(iphdr), sizeof(rep)); | |
228 | if(iphdr.protocol != IPPROTO_ICMP) | |
229 | continue; | |
230 | if(rep.type != ICMP_NAMEREP) | |
231 | continue; | |
232 | if((ntohs(rep.id) != id) || (ntohs(rep.seq != 0))) | |
233 | continue; | |
234 | ||
235 | break; | |
236 | } | |
237 | } | |
238 | ||
239 | printdn(stdout, buf + sizeof(iphdr) + sizeof(rep), ret - sizeof(iphdr) - sizeof(rep)); | |
240 | ||
241 | close(s); | |
51a62941 | 242 | } |
3d6143ec | 243 | |
51a62941 DC |
244 | return(0); |
245 | } |