Commit | Line | Data |
---|---|---|
732b8359 DC |
1 | /* |
2 | * nss-icmp or libnss_icmp - GNU C Library NSS module to query host | |
3 | * names by ICMP. | |
4 | * Copyright (C) 2005 Fredrik Tolf <fredrik@dolda2000.com> | |
5 | * | |
6 | * This library is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Library General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * This library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Library General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Library General Public | |
17 | * License along with this library; if not, write to the Free | |
18 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
19 | * MA 02111-1307, USA | |
20 | */ | |
21 | ||
2dec74ab DC |
22 | #include <stdlib.h> |
23 | #include <stdio.h> | |
24 | #include <unistd.h> | |
25 | #include <string.h> | |
26 | #include <errno.h> | |
f0df8f66 | 27 | #include <time.h> |
2dec74ab DC |
28 | #include <sys/socket.h> |
29 | #include <netinet/in.h> | |
30 | #include <netdb.h> | |
31 | #include <arpa/inet.h> | |
32 | #include <nss.h> | |
33 | #include <sys/types.h> | |
34 | #include <fcntl.h> | |
46c36380 | 35 | #include <sys/wait.h> |
2dec74ab | 36 | |
15a913c2 | 37 | #define CONFIGFILE "/etc/nss-icmp.conf" |
78d913fb DC |
38 | #if 0 |
39 | #define DEBUGP(format...) fprintf(stderr, "nss-icmp: " format); | |
40 | #else | |
41 | #define DEBUGP(format...) | |
42 | #endif | |
15a913c2 DC |
43 | |
44 | struct cache { | |
45 | struct cache *next, *prev; | |
46 | char *addr; | |
47 | socklen_t addrlen; | |
48 | int af; | |
49 | int notfound; | |
50 | char **names; | |
f0df8f66 | 51 | time_t at, ttl; |
15a913c2 DC |
52 | }; |
53 | ||
54 | static int inited = 0; | |
55 | static int timeout = -1; | |
56 | static int usecache = 1; | |
f0df8f66 | 57 | static time_t nfttl = 300; |
15a913c2 DC |
58 | static struct cache *cache = NULL; |
59 | ||
60 | static void readconfig(void) | |
61 | { | |
62 | FILE *f; | |
63 | char linebuf[1024]; | |
64 | char *p, *p2; | |
65 | ||
66 | if((f = fopen(CONFIGFILE, "r")) == NULL) | |
67 | return; | |
68 | ||
69 | while(fgets(linebuf, sizeof(linebuf), f) != NULL) { | |
70 | if(linebuf[0] == '#') | |
71 | continue; | |
72 | if((p = strchr(linebuf, '\n')) != NULL) | |
73 | *p = 0; | |
74 | if((p = strchr(linebuf, ' ')) != NULL) { | |
75 | p2 = p + 1; | |
76 | *p = 0; | |
77 | } | |
78 | if(!strcmp(linebuf, "timeout")) { | |
79 | if(p2 == NULL) | |
80 | continue; | |
81 | timeout = atoi(p2); | |
82 | } | |
f0df8f66 DC |
83 | if(!strcmp(linebuf, "ttlnotfound")) { |
84 | if(p2 == NULL) | |
85 | continue; | |
86 | nfttl = atoi(p2); | |
87 | } | |
15a913c2 DC |
88 | if(!strcmp(linebuf, "nocache")) { |
89 | usecache = 0; | |
90 | } | |
91 | } | |
92 | ||
93 | fclose(f); | |
94 | } | |
95 | ||
96 | static void freecache(struct cache *cc) | |
97 | { | |
98 | int i; | |
99 | ||
100 | if(cc->next != NULL) | |
101 | cc->next->prev = cc->prev; | |
102 | if(cc->prev != NULL) | |
103 | cc->prev->next = cc->next; | |
104 | if(cc == cache) | |
105 | cache = cc->next; | |
106 | if(cc->addr != NULL) | |
107 | free(cc->addr); | |
108 | if(cc->names != NULL) { | |
109 | for(i = 0; cc->names[i] != NULL; i++) | |
110 | free(cc->names[i]); | |
111 | free(cc->names); | |
112 | } | |
113 | free(cc); | |
114 | } | |
115 | ||
f0df8f66 | 116 | static void cachenotfound(const void *addr, socklen_t len, int af, time_t ttl) |
15a913c2 DC |
117 | { |
118 | struct cache *cc; | |
119 | ||
120 | for(cc = cache; cc != NULL; cc = cc->next) { | |
121 | if((cc->af == af) && (cc->addrlen == len) && !memcmp(cc->addr, addr, len)) | |
122 | break; | |
123 | } | |
124 | if(cc == NULL) { | |
125 | if((cc = malloc(sizeof(*cc))) == NULL) | |
126 | return; | |
127 | memset(cc, 0, sizeof(*cc)); | |
128 | if((cc->addr = malloc(len)) == NULL) { | |
129 | freecache(cc); | |
130 | return; | |
131 | } | |
132 | memcpy(cc->addr, addr, len); | |
133 | cc->addrlen = len; | |
134 | cc->af = af; | |
f0df8f66 DC |
135 | cc->at = time(NULL); |
136 | cc->ttl = ttl; | |
15a913c2 DC |
137 | |
138 | cc->notfound = 1; | |
139 | ||
140 | cc->next = cache; | |
141 | if(cache != NULL) | |
142 | cache->prev = cc; | |
143 | cache = cc; | |
144 | } | |
145 | } | |
146 | ||
f0df8f66 | 147 | static void updatecache(const void *addr, socklen_t len, int af, char **names, time_t ttl) |
15a913c2 DC |
148 | { |
149 | int i; | |
150 | struct cache *cc; | |
151 | ||
152 | for(cc = cache; cc != NULL; cc = cc->next) { | |
f0df8f66 | 153 | if((cc->af == af) && (cc->addrlen == len) && !memcmp(cc->addr, addr, len)) |
15a913c2 DC |
154 | break; |
155 | } | |
156 | if(cc == NULL) { | |
157 | if((cc = malloc(sizeof(*cc))) == NULL) | |
158 | return; | |
159 | memset(cc, 0, sizeof(*cc)); | |
f0df8f66 | 160 | if((cc->addr = malloc(len)) == NULL) { |
15a913c2 DC |
161 | freecache(cc); |
162 | return; | |
163 | } | |
f0df8f66 DC |
164 | memcpy(cc->addr, addr, len); |
165 | cc->addrlen = len; | |
166 | cc->af = af; | |
167 | cc->at = time(NULL); | |
168 | cc->ttl = ttl; | |
15a913c2 | 169 | |
f0df8f66 | 170 | for(i = 0; names[i] != NULL; i++); |
15a913c2 DC |
171 | if((cc->names = malloc(sizeof(*(cc->names)) * (i + 1))) == NULL) { |
172 | freecache(cc); | |
173 | return; | |
174 | } | |
175 | memset(cc->names, 0, sizeof(*(cc->names)) * (i + 1)); | |
f0df8f66 DC |
176 | for(i = 0; names[i] != NULL; i++) { |
177 | if((cc->names[i] = malloc(strlen(names[i]) + 1)) == NULL) { | |
15a913c2 DC |
178 | freecache(cc); |
179 | return; | |
180 | } | |
f0df8f66 | 181 | strcpy(cc->names[i], names[i]); |
15a913c2 DC |
182 | } |
183 | ||
184 | cc->next = cache; | |
185 | if(cache != NULL) | |
186 | cache->prev = cc; | |
187 | cache = cc; | |
188 | } | |
189 | } | |
190 | ||
f0df8f66 DC |
191 | static void expirecache(void) |
192 | { | |
193 | struct cache *cc, *next; | |
194 | time_t now; | |
195 | ||
196 | now = time(NULL); | |
197 | for(cc = cache; cc != NULL; cc = next) { | |
198 | next = cc->next; | |
199 | if(now - cc->at > cc->ttl) { | |
200 | freecache(cc); | |
201 | continue; | |
202 | } | |
203 | } | |
204 | } | |
205 | ||
2dec74ab DC |
206 | enum nss_status _nss_icmp_gethostbyaddr_r(const void *addr, socklen_t len, int af, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop) |
207 | { | |
15a913c2 | 208 | int i, ret; |
2dec74ab DC |
209 | struct retstruct { |
210 | char *aliaslist[16]; | |
211 | char *addrlist[2]; | |
212 | char retaddr[16]; | |
213 | } *retbuf; | |
214 | char addrbuf[1024]; | |
f0df8f66 | 215 | int an, thislen, ttl; |
2dec74ab DC |
216 | char *p, *p2, *p3; |
217 | u_int8_t *ap; | |
218 | pid_t child; | |
219 | int pfd[2]; | |
220 | int rl; | |
46c36380 | 221 | int status; |
15a913c2 DC |
222 | struct cache *cc; |
223 | ||
224 | if(!inited) { | |
225 | readconfig(); | |
226 | inited = 1; | |
227 | } | |
2dec74ab DC |
228 | |
229 | retbuf = (struct retstruct *)buffer; | |
230 | if((buflen < sizeof(*retbuf)) || (len > sizeof(retbuf->retaddr))) { | |
231 | *errnop = ENOMEM; | |
232 | *h_errnop = NETDB_INTERNAL; | |
233 | return(NSS_STATUS_UNAVAIL); | |
234 | } | |
235 | ||
78d913fb DC |
236 | DEBUGP("starting lookup\n"); |
237 | ||
f416a8cd | 238 | if(usecache) { |
f0df8f66 | 239 | expirecache(); |
f416a8cd DC |
240 | for(cc = cache; cc != NULL; cc = cc->next) { |
241 | if((cc->af == af) && (cc->addrlen == len) && !memcmp(cc->addr, addr, len)) | |
242 | break; | |
243 | } | |
244 | } else { | |
245 | cc = NULL; | |
2dec74ab DC |
246 | } |
247 | ||
15a913c2 | 248 | if(cc == NULL) { |
78d913fb | 249 | DEBUGP("address not in cache, looking up for real\n"); |
15a913c2 DC |
250 | ap = (u_int8_t *)addr; |
251 | if(inet_ntop(af, addr, addrbuf, sizeof(addrbuf)) == NULL) { | |
2dec74ab DC |
252 | *errnop = errno; |
253 | *h_errnop = NETDB_INTERNAL; | |
2dec74ab DC |
254 | return(NSS_STATUS_UNAVAIL); |
255 | } | |
78d913fb | 256 | DEBUGP("address is %s\n", addrbuf); |
15a913c2 DC |
257 | |
258 | if(pipe(pfd)) { | |
259 | *errnop = errno; | |
2dec74ab | 260 | *h_errnop = NETDB_INTERNAL; |
2dec74ab DC |
261 | return(NSS_STATUS_UNAVAIL); |
262 | } | |
15a913c2 DC |
263 | /* I honestly don't know if it is considered OK to fork in other |
264 | * people's programs. We need a SUID worker, though, so there's | |
265 | * little choice that I can see. */ | |
266 | if((child = fork()) < 0) { | |
267 | *errnop = errno; | |
2dec74ab DC |
268 | *h_errnop = NETDB_INTERNAL; |
269 | return(NSS_STATUS_UNAVAIL); | |
270 | } | |
15a913c2 DC |
271 | |
272 | if(child == 0) { | |
273 | int i, fd; | |
274 | char timeoutbuf[128]; | |
275 | ||
276 | if((fd = open("/dev/null", O_WRONLY)) < 0) | |
277 | exit(127); | |
278 | close(pfd[0]); | |
279 | dup2(pfd[1], 1); | |
280 | dup2(fd, 2); | |
281 | for(i = 3; i < FD_SETSIZE; i++) | |
282 | close(i); | |
283 | ||
284 | if(timeout != -1) { | |
285 | snprintf(timeoutbuf, sizeof(timeoutbuf), "%i", timeout); | |
f0df8f66 | 286 | execlp("idnlookup", "idnlookup", "-Tt", timeoutbuf, addrbuf, NULL); |
15a913c2 | 287 | } else { |
f0df8f66 | 288 | execlp("idnlookup", "idnlookup", "-T", addrbuf, NULL); |
15a913c2 DC |
289 | } |
290 | exit(127); | |
291 | } | |
292 | ||
293 | close(pfd[1]); | |
294 | ||
295 | rl = 0; | |
296 | do { | |
297 | ret = read(pfd[0], addrbuf + rl, sizeof(addrbuf) - rl); | |
298 | if(ret < 0) { | |
299 | *errnop = errno; | |
300 | *h_errnop = NETDB_INTERNAL; | |
301 | close(pfd[0]); | |
302 | return(NSS_STATUS_UNAVAIL); | |
303 | } | |
304 | rl += ret; | |
305 | if(rl >= sizeof(addrbuf) - 1) { | |
306 | *errnop = ENOMEM; | |
307 | *h_errnop = NETDB_INTERNAL; | |
308 | close(pfd[0]); | |
309 | return(NSS_STATUS_UNAVAIL); | |
310 | } | |
311 | } while(ret != 0); | |
312 | addrbuf[rl] = 0; | |
313 | close(pfd[0]); | |
f0df8f66 | 314 | |
46c36380 DC |
315 | waitpid(child, &status, 0); |
316 | ||
f0df8f66 DC |
317 | if((p = strchr(addrbuf, '\n')) == NULL) { |
318 | if(usecache) | |
319 | cachenotfound(addr, len, af, nfttl); | |
320 | *h_errnop = TRY_AGAIN; /* XXX: Is this correct? */ | |
321 | return(NSS_STATUS_NOTFOUND); | |
322 | } | |
323 | *(p++) = 0; | |
324 | ttl = atoi(addrbuf); | |
325 | ||
15a913c2 | 326 | an = 0; |
15a913c2 DC |
327 | p3 = buffer + sizeof(*retbuf); |
328 | while((p2 = strchr(p, '\n')) != NULL) { | |
329 | *p2 = 0; | |
330 | thislen = p2 - p; | |
331 | if(thislen == 0) | |
332 | continue; | |
333 | if((p3 - buffer) + thislen + 1 > buflen) { | |
334 | *errnop = ENOMEM; | |
335 | *h_errnop = NETDB_INTERNAL; | |
336 | return(NSS_STATUS_UNAVAIL); | |
337 | } | |
338 | memcpy(p3, p, thislen + 1); | |
339 | retbuf->aliaslist[an] = p3; | |
340 | p3 += thislen + 1; | |
341 | p = p2 + 1; | |
342 | if(++an == 16) { | |
343 | *errnop = ENOMEM; | |
344 | *h_errnop = NETDB_INTERNAL; | |
345 | return(NSS_STATUS_UNAVAIL); | |
346 | } | |
347 | } | |
348 | if(an == 0) { | |
f416a8cd | 349 | if(usecache) |
f0df8f66 | 350 | cachenotfound(addr, len, af, nfttl); |
15a913c2 DC |
351 | *h_errnop = TRY_AGAIN; /* XXX: Is this correct? */ |
352 | return(NSS_STATUS_NOTFOUND); | |
353 | } | |
354 | retbuf->aliaslist[an] = NULL; | |
f0df8f66 DC |
355 | |
356 | if(usecache) | |
357 | updatecache(addr, len, af, retbuf->aliaslist, ttl); | |
15a913c2 | 358 | } else { |
78d913fb | 359 | DEBUGP("address found in cache\n"); |
15a913c2 DC |
360 | if(cc->notfound) { |
361 | *h_errnop = TRY_AGAIN; /* XXX: Is this correct? */ | |
362 | return(NSS_STATUS_NOTFOUND); | |
363 | } | |
364 | ||
365 | p3 = buffer + sizeof(*retbuf); | |
366 | for(i = 0; cc->names[i] != NULL; i++) { | |
367 | thislen = strlen(cc->names[i]); | |
78d913fb | 368 | DEBUGP("filling in address %s, length %i\n", cc->names[i], thislen); |
15a913c2 DC |
369 | if((p3 - buffer) + thislen + 1 > buflen) { |
370 | *errnop = ENOMEM; | |
371 | *h_errnop = NETDB_INTERNAL; | |
372 | return(NSS_STATUS_UNAVAIL); | |
373 | } | |
374 | memcpy(p3, cc->names[i], thislen + 1); | |
78d913fb | 375 | retbuf->aliaslist[i] = p3; |
15a913c2 | 376 | p3 += thislen + 1; |
2dec74ab | 377 | } |
78d913fb | 378 | retbuf->aliaslist[i] = NULL; |
2dec74ab | 379 | } |
2dec74ab | 380 | |
78d913fb | 381 | DEBUGP("returning hostent\n"); |
2dec74ab DC |
382 | memcpy(retbuf->retaddr, addr, len); |
383 | retbuf->addrlist[0] = retbuf->retaddr; | |
384 | retbuf->addrlist[1] = NULL; | |
385 | result->h_name = retbuf->aliaslist[0]; | |
386 | result->h_aliases = retbuf->aliaslist; | |
387 | result->h_addr_list = retbuf->addrlist; | |
388 | result->h_addrtype = af; | |
389 | result->h_length = len; | |
390 | ||
391 | *h_errnop = NETDB_SUCCESS; | |
78d913fb | 392 | DEBUGP("returning\n"); |
2dec74ab DC |
393 | return(NSS_STATUS_SUCCESS); |
394 | } | |
732b8359 DC |
395 | |
396 | /* | |
397 | * Local Variables: | |
398 | * compile-command: "gcc -shared -Wall -g -o libnss_icmp.so.2 nss-icmp.c" | |
399 | * End: | |
400 | */ |