masqmail-0.2

view src/lookup.c @ 179:ec3fe72a3e99

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Fixed an important bug with folded headers! g_strconcat() returns a *copy* of the string, but hdr->value still pointed to the old header (which probably was a memory leak, too). If the folded part had been quite small it was likely that the new string was at the same position as the old one, thus making everything go well. But if pretty long headers were folded several times it was likely that the new string was allocated somewhere else in memory, thus breaking things. In result mails to lots of recipients (folded header) were frequently only sent to the ones in the first line. Sorry for the inconvenience.
author meillo@marmaro.de
date Fri, 03 Jun 2011 09:52:17 +0200
parents 26e34ae9a3e3
children
line source
1 /* MasqMail Copyright (C) Oliver Kurth,
2 *
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation; either version 2 of the License, or
6 * (at your option) any later version.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
16 */
17
18 #include <sys/types.h>
19 #include <netinet/in.h>
20 #include <arpa/nameser.h>
21 #include <resolv.h>
22
23 #include "masqmail.h"
24
25 #ifdef RESOLV_TEST
26 #undef DEBUG
27 #define DEBUG(x) if(x > 0)
28 #define debugf g_print
29 #endif
30
31 #ifdef ENABLE_RESOLVER
32
33 static union {
34 HEADER hdr;
35 unsigned char buf[PACKETSZ];
36 } response;
37 static unsigned char *resp_end;
38 static unsigned char *resp_pos;
39
40 static int num_answers;
41 static char name[MAX_DNSNAME];
42
43 unsigned short rr_type;
44 unsigned short rr_dlen;
45
46 static unsigned short
47 getshort(unsigned char *c)
48 {
49 unsigned short u;
50 u = c[0];
51 return (u << 8) + c[1];
52 }
53
54 static int
55 dns_resolve(char *domain, int type, gboolean do_search)
56 {
57 int n;
58 int i;
59
60 int resp_len;
61 /*errno = 0; */
62
63 /*
64 if (!stralloc_copy(&glue,domain)) return DNS_MEM;
65 if (!stralloc_0(&glue)) return DNS_MEM;
66 */
67
68 // resp_len = res_query(domain, C_IN, type, response.buf, sizeof(response));
69 DEBUG(5) debugf("DNS: before res_search()\n");
70 if (do_search)
71 resp_len = res_search(domain, C_IN, type, response.buf, sizeof(response));
72 else
73 resp_len = res_query(domain, C_IN, type, response.buf, sizeof(response));
74 DEBUG(5) debugf("DBG: after res_search()\n");
75
76 if (resp_len <= 0) {
77 /*
78 if (errno == ECONNREFUSED) return DNS_SOFT;
79 if (h_errno == TRY_AGAIN) return DNS_SOFT;
80 return DNS_HARD;
81 */
82 return -1;
83 }
84 if (resp_len >= sizeof(response))
85 resp_len = sizeof(response);
86
87 resp_end = response.buf + resp_len;
88 resp_pos = response.buf + sizeof(HEADER);
89 n = ntohs(response.hdr.qdcount);
90
91 while (n-- > 0) {
92 i = dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME);
93 if (i < 0)
94 return -1;
95 DEBUG(5) debugf("DBG: resolve name = %s\n", name);
96 resp_pos += i;
97 i = resp_end - resp_pos;
98 if (i < QFIXEDSZ)
99 return -1;
100 resp_pos += QFIXEDSZ;
101 }
102 num_answers = ntohs(response.hdr.ancount);
103
104 return 0;
105 }
106
107 static int
108 dns_next()
109 {
110 int i;
111
112 if (num_answers <= 0)
113 return 2;
114 num_answers--;
115
116 if (resp_pos == resp_end)
117 return -1; /* soft */
118
119 i = dn_expand(response.buf, resp_end, resp_pos, name, 256);
120 if (i < 0)
121 return -1; /* soft */
122 resp_pos += i;
123
124 i = resp_end - resp_pos;
125 if (i < 4 + 3 * 2)
126 return -1; /* soft */
127
128 rr_type = getshort(resp_pos);
129 rr_dlen = getshort(resp_pos + 8);
130 resp_pos += 10;
131
132 return 0;
133 }
134
135 static int
136 dns_getip(guint32 * ip)
137 {
138 int ret;
139
140 if ((ret = dns_next()))
141 return ret;
142
143 if (rr_type == T_A) {
144 if (rr_dlen < 4)
145 return -1; /* soft */
146 *ip = *(guint32 *) (resp_pos);
147 DEBUG(5) debugf("DNS: dns_getip(): ip = %s\n", inet_ntoa(*(struct in_addr *) ip));
148 resp_pos += rr_dlen;
149
150 return 1;
151 }
152 resp_pos += rr_dlen;
153 return 0;
154 }
155
156 static int
157 dns_getmx(int *pref)
158 {
159 int ret;
160
161 if ((ret = dns_next()))
162 return ret;
163
164 if (rr_type == T_MX) {
165 if (rr_dlen < 3)
166 return -1; /* soft */
167
168 *pref = (resp_pos[0] << 8) + resp_pos[1];
169 if (dn_expand(response.buf, resp_end, resp_pos + 2, name, MAX_DNSNAME) < 0)
170 return -1;
171
172 resp_pos += rr_dlen;
173
174 return 1;
175 }
176 resp_pos += rr_dlen;
177 return 0;
178 }
179
180 /*
181 static int
182 dns_getname(int type)
183 {
184 int ret;
185
186 if((ret = dns_next())) return ret;
187
188 if (rr_type == type){
189 if (dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME) < 0)
190 return -1;
191
192 resp_pos += rr_dlen;
193
194 return 1;
195 }
196 resp_pos += rr_dlen;
197 return 0;
198 }
199 */
200
201 static int
202 dns_look_ip(gchar * domain, guint32 * ip)
203 {
204 gchar *n = domain;
205
206 while (TRUE) {
207 if (dns_resolve(n, T_A, FALSE) == 0) {
208 dns_next();
209 if (rr_type == T_A) {
210 if (rr_dlen < 4)
211 return -1; /* soft */
212 *ip = *(guint32 *) (resp_pos);
213
214 DEBUG(5) debugf("DNS: dns_look_ip(): ip = %s\n", inet_ntoa(*(struct in_addr *) ip));
215
216 resp_pos += rr_dlen;
217 return 0;
218 } else if (rr_type == T_CNAME) {
219 if (dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME) < 0)
220 return -1;
221
222 DEBUG(5) debugf("DNS: (CNAME) dns_look_ip(): name = %s\n", name);
223
224 resp_pos += rr_dlen;
225 n = name;
226 } else
227 return -1;
228 } else
229 return -1;
230 }
231 }
232
233 GList*
234 resolve_dns_a(GList * list, gchar * domain)
235 {
236 int ret;
237
238 DEBUG(5) debugf("DNS: resolve_dns_a entered\n");
239
240 if (dns_resolve(domain, T_A, TRUE) == 0) {
241 mxip_addr mxip;
242 while ((ret = dns_getip(&(mxip.ip))) != 2) {
243 if (ret == 1) {
244 mxip.name = g_strdup(name);
245 mxip.pref = 0;
246 list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
247 }
248 }
249 }
250 return list;
251 }
252
253 static gint
254 _mx_sort_func(gconstpointer aa, gconstpointer bb)
255 {
256 const mxip_addr *a = (mxip_addr *) aa;
257 const mxip_addr *b = (mxip_addr *) bb;
258
259 if (a->pref == b->pref)
260 return a->ip - b->ip;
261 else
262 return a->pref - b->pref;
263 }
264
265 GList*
266 resolve_dns_mx(GList * list, gchar * domain)
267 {
268 GList *node;
269 int ret;
270 int cnt = 0;
271
272 DEBUG(5) debugf("DNS: resolve_dns_mx entered\n");
273
274 if (dns_resolve(domain, T_MX, TRUE) == 0) {
275 GList *node_next;
276 mxip_addr mxip;
277 while ((ret = dns_getmx(&(mxip.pref))) != 2) {
278 if (ret == 1) {
279 mxip.name = g_strdup(name);
280 mxip.ip = rand();
281 list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
282 cnt++;
283 }
284 }
285
286 DEBUG(5) debugf("DNS: found %d mx records\n", cnt);
287
288 /* to randomize sequences with equal pref values,
289 we temporarily 'misused' the ip field and
290 put a random number in it as a secondary sort key.
291 */
292 list = g_list_sort(list, _mx_sort_func);
293
294 /* CNAME resolving has to be added as well. */
295
296 for (node = g_list_first(list); node != NULL; node = node_next) {
297
298 mxip_addr *p_mxip = (mxip_addr *) (node->data);
299 node_next = g_list_next(node);
300
301 if (dns_look_ip(p_mxip->name, &(p_mxip->ip)) != 0) {
302 DEBUG(1) debugf("DNS: could not resolve target of mx %s\n", p_mxip->name);
303 list = g_list_remove_link(list, node);
304 g_free(node->data);
305 g_list_free_1(node);
306 }
307 }
308 }
309 return list;
310 }
311
312 #endif
313
314 /* now something completely different... */
315
316 GList*
317 resolve_byname(GList * list, gchar * domain)
318 {
319 struct hostent *hent;
320
321 DEBUG(5) debugf("DNS: resolve_byname entered\n");
322
323 if ((hent = gethostbyname(domain))) {
324 char *haddr;
325 int i = 0;
326 while ((haddr = hent->h_addr_list[i++])) {
327 mxip_addr mxip;
328 mxip.ip = *(guint32 *) (haddr);
329 mxip.pref = 0;
330 mxip.name = g_strdup(hent->h_name);
331 list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
332 }
333 }
334 return list;
335 }
336
337 #ifdef RESOLV_TEST
338 int
339 main(int argc, char *argv[])
340 {
341 GList *addr_list = NULL, *node;
342
343 g_print("starting res_init()\n");
344 g_print("retrans = %d, retry = %d\n", _res.retrans, _res.retry);
345 if (res_init() == 0) {
346 addr_list = resolve_dns_a(NULL, argv[1]);
347 g_print("A:\n");
348 foreach(addr_list, node) {
349 mxip_addr *p_mxip = (mxip_addr *) (node->data);
350 printf("name = %s\n IP = %s\n", p_mxip->name, inet_ntoa(*(struct in_addr *) &(p_mxip->ip)));
351 }
352 addr_list = resolve_dns_mx(NULL, argv[1]);
353 g_print("MX:\n");
354 foreach(addr_list, node) {
355 mxip_addr *p_mxip = (mxip_addr *) (node->data);
356 printf("name = %s\n IP = %s pref = %d\n", p_mxip->name,
357 inet_ntoa(*(struct in_addr *) &(p_mxip->ip)), p_mxip->pref);
358 }
359 {
360 guint32 ip;
361 dns_look_ip(argv[1], &ip);
362 printf("dns_look_ip: %s\n", inet_ntoa(*((struct in_addr *) (&ip))));
363 }
364 } else
365 printf("res_init() failed.\n");
366 }
367 #endif