masqmail

annotate src/lookup.c @ 117:5ec5e6637049

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added server-side SMTP SIZE support (patch by Paolo) ``SIZE 0'' (= unlimited) is currently not supported client-side support was already implemented
author meillo@marmaro.de
date Thu, 01 Jul 2010 13:08:53 +0200
parents 26e34ae9a3e3
children 116b0269c934
rev   line source
meillo@0 1 /* MasqMail Copyright (C) Oliver Kurth,
meillo@0 2 *
meillo@0 3 * This program is free software; you can redistribute it and/or modify
meillo@0 4 * it under the terms of the GNU General Public License as published by
meillo@0 5 * the Free Software Foundation; either version 2 of the License, or
meillo@0 6 * (at your option) any later version.
meillo@10 7 *
meillo@0 8 * This program is distributed in the hope that it will be useful,
meillo@0 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
meillo@0 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
meillo@0 11 * GNU General Public License for more details.
meillo@0 12 *
meillo@0 13 * You should have received a copy of the GNU General Public License
meillo@0 14 * along with this program; if not, write to the Free Software
meillo@0 15 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
meillo@0 16 */
meillo@0 17
meillo@0 18 #include <sys/types.h>
meillo@0 19 #include <netinet/in.h>
meillo@0 20 #include <arpa/nameser.h>
meillo@0 21 #include <resolv.h>
meillo@0 22
meillo@0 23 #include "masqmail.h"
meillo@0 24
meillo@0 25 #ifdef RESOLV_TEST
meillo@0 26 #undef DEBUG
meillo@0 27 #define DEBUG(x) if(x > 0)
meillo@0 28 #define debugf g_print
meillo@0 29 #endif
meillo@0 30
meillo@0 31 #ifdef ENABLE_RESOLVER
meillo@0 32
meillo@0 33 static union {
meillo@10 34 HEADER hdr;
meillo@10 35 unsigned char buf[PACKETSZ];
meillo@0 36 } response;
meillo@0 37 static unsigned char *resp_end;
meillo@0 38 static unsigned char *resp_pos;
meillo@0 39
meillo@0 40 static int num_answers;
meillo@0 41 static char name[MAX_DNSNAME];
meillo@0 42
meillo@0 43 unsigned short rr_type;
meillo@0 44 unsigned short rr_dlen;
meillo@0 45
meillo@10 46 static unsigned short
meillo@10 47 getshort(unsigned char *c)
meillo@0 48 {
meillo@10 49 unsigned short u;
meillo@10 50 u = c[0];
meillo@10 51 return (u << 8) + c[1];
meillo@0 52 }
meillo@0 53
meillo@10 54 static int
meillo@10 55 dns_resolve(char *domain, int type, gboolean do_search)
meillo@0 56 {
meillo@10 57 int n;
meillo@10 58 int i;
meillo@0 59
meillo@10 60 int resp_len;
meillo@10 61 /*errno = 0; */
meillo@0 62
meillo@10 63 /*
meillo@10 64 if (!stralloc_copy(&glue,domain)) return DNS_MEM;
meillo@10 65 if (!stralloc_0(&glue)) return DNS_MEM;
meillo@10 66 */
meillo@0 67
meillo@10 68 // resp_len = res_query(domain, C_IN, type, response.buf, sizeof(response));
meillo@10 69 DEBUG(5) debugf("DNS: before res_search()\n");
meillo@10 70 if (do_search)
meillo@10 71 resp_len = res_search(domain, C_IN, type, response.buf, sizeof(response));
meillo@10 72 else
meillo@10 73 resp_len = res_query(domain, C_IN, type, response.buf, sizeof(response));
meillo@10 74 DEBUG(5) debugf("DBG: after res_search()\n");
meillo@0 75
meillo@10 76 if (resp_len <= 0) {
meillo@10 77 /*
meillo@10 78 if (errno == ECONNREFUSED) return DNS_SOFT;
meillo@10 79 if (h_errno == TRY_AGAIN) return DNS_SOFT;
meillo@10 80 return DNS_HARD;
meillo@10 81 */
meillo@10 82 return -1;
meillo@10 83 }
meillo@10 84 if (resp_len >= sizeof(response))
meillo@10 85 resp_len = sizeof(response);
meillo@0 86
meillo@10 87 resp_end = response.buf + resp_len;
meillo@10 88 resp_pos = response.buf + sizeof(HEADER);
meillo@10 89 n = ntohs(response.hdr.qdcount);
meillo@0 90
meillo@10 91 while (n-- > 0) {
meillo@10 92 i = dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME);
meillo@10 93 if (i < 0)
meillo@10 94 return -1;
meillo@10 95 DEBUG(5) debugf("DBG: resolve name = %s\n", name);
meillo@10 96 resp_pos += i;
meillo@10 97 i = resp_end - resp_pos;
meillo@10 98 if (i < QFIXEDSZ)
meillo@10 99 return -1;
meillo@10 100 resp_pos += QFIXEDSZ;
meillo@10 101 }
meillo@10 102 num_answers = ntohs(response.hdr.ancount);
meillo@0 103
meillo@10 104 return 0;
meillo@0 105 }
meillo@0 106
meillo@10 107 static int
meillo@10 108 dns_next()
meillo@0 109 {
meillo@10 110 int i;
meillo@0 111
meillo@10 112 if (num_answers <= 0)
meillo@10 113 return 2;
meillo@10 114 num_answers--;
meillo@0 115
meillo@10 116 if (resp_pos == resp_end)
meillo@10 117 return -1; /* soft */
meillo@0 118
meillo@10 119 i = dn_expand(response.buf, resp_end, resp_pos, name, 256);
meillo@10 120 if (i < 0)
meillo@10 121 return -1; /* soft */
meillo@10 122 resp_pos += i;
meillo@0 123
meillo@10 124 i = resp_end - resp_pos;
meillo@10 125 if (i < 4 + 3 * 2)
meillo@10 126 return -1; /* soft */
meillo@0 127
meillo@10 128 rr_type = getshort(resp_pos);
meillo@10 129 rr_dlen = getshort(resp_pos + 8);
meillo@10 130 resp_pos += 10;
meillo@10 131
meillo@10 132 return 0;
meillo@0 133 }
meillo@0 134
meillo@10 135 static int
meillo@10 136 dns_getip(guint32 * ip)
meillo@0 137 {
meillo@10 138 int ret;
meillo@0 139
meillo@10 140 if ((ret = dns_next()))
meillo@10 141 return ret;
meillo@0 142
meillo@10 143 if (rr_type == T_A) {
meillo@10 144 if (rr_dlen < 4)
meillo@10 145 return -1; /* soft */
meillo@10 146 *ip = *(guint32 *) (resp_pos);
meillo@10 147 DEBUG(5) debugf("DNS: dns_getip(): ip = %s\n", inet_ntoa(*(struct in_addr *) ip));
meillo@10 148 resp_pos += rr_dlen;
meillo@0 149
meillo@10 150 return 1;
meillo@10 151 }
meillo@10 152 resp_pos += rr_dlen;
meillo@10 153 return 0;
meillo@0 154 }
meillo@0 155
meillo@10 156 static int
meillo@10 157 dns_getmx(int *pref)
meillo@0 158 {
meillo@10 159 int ret;
meillo@0 160
meillo@10 161 if ((ret = dns_next()))
meillo@10 162 return ret;
meillo@0 163
meillo@10 164 if (rr_type == T_MX) {
meillo@10 165 if (rr_dlen < 3)
meillo@10 166 return -1; /* soft */
meillo@0 167
meillo@10 168 *pref = (resp_pos[0] << 8) + resp_pos[1];
meillo@10 169 if (dn_expand(response.buf, resp_end, resp_pos + 2, name, MAX_DNSNAME) < 0)
meillo@10 170 return -1;
meillo@0 171
meillo@10 172 resp_pos += rr_dlen;
meillo@10 173
meillo@10 174 return 1;
meillo@10 175 }
meillo@10 176 resp_pos += rr_dlen;
meillo@10 177 return 0;
meillo@0 178 }
meillo@0 179
meillo@0 180 /*
meillo@10 181 static int
meillo@10 182 dns_getname(int type)
meillo@0 183 {
meillo@0 184 int ret;
meillo@0 185
meillo@0 186 if((ret = dns_next())) return ret;
meillo@0 187
meillo@0 188 if (rr_type == type){
meillo@0 189 if (dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME) < 0)
meillo@0 190 return -1;
meillo@10 191
meillo@0 192 resp_pos += rr_dlen;
meillo@0 193
meillo@0 194 return 1;
meillo@0 195 }
meillo@0 196 resp_pos += rr_dlen;
meillo@0 197 return 0;
meillo@0 198 }
meillo@0 199 */
meillo@0 200
meillo@10 201 static int
meillo@10 202 dns_look_ip(gchar * domain, guint32 * ip)
meillo@0 203 {
meillo@10 204 gchar *n = domain;
meillo@0 205
meillo@10 206 while (TRUE) {
meillo@10 207 if (dns_resolve(n, T_A, FALSE) == 0) {
meillo@10 208 dns_next();
meillo@10 209 if (rr_type == T_A) {
meillo@10 210 if (rr_dlen < 4)
meillo@10 211 return -1; /* soft */
meillo@10 212 *ip = *(guint32 *) (resp_pos);
meillo@0 213
meillo@10 214 DEBUG(5) debugf("DNS: dns_look_ip(): ip = %s\n", inet_ntoa(*(struct in_addr *) ip));
meillo@10 215
meillo@10 216 resp_pos += rr_dlen;
meillo@10 217 return 0;
meillo@10 218 } else if (rr_type == T_CNAME) {
meillo@10 219 if (dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME) < 0)
meillo@10 220 return -1;
meillo@10 221
meillo@10 222 DEBUG(5) debugf("DNS: (CNAME) dns_look_ip(): name = %s\n", name);
meillo@10 223
meillo@10 224 resp_pos += rr_dlen;
meillo@10 225 n = name;
meillo@10 226 } else
meillo@10 227 return -1;
meillo@10 228 } else
meillo@10 229 return -1;
meillo@10 230 }
meillo@0 231 }
meillo@0 232
meillo@10 233 GList*
meillo@10 234 resolve_dns_a(GList * list, gchar * domain)
meillo@0 235 {
meillo@10 236 int ret;
meillo@0 237
meillo@10 238 DEBUG(5) debugf("DNS: resolve_dns_a entered\n");
meillo@0 239
meillo@10 240 if (dns_resolve(domain, T_A, TRUE) == 0) {
meillo@10 241 mxip_addr mxip;
meillo@10 242 while ((ret = dns_getip(&(mxip.ip))) != 2) {
meillo@10 243 if (ret == 1) {
meillo@10 244 mxip.name = g_strdup(name);
meillo@10 245 mxip.pref = 0;
meillo@10 246 list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
meillo@10 247 }
meillo@10 248 }
meillo@10 249 }
meillo@10 250 return list;
meillo@0 251 }
meillo@0 252
meillo@10 253 static gint
meillo@10 254 _mx_sort_func(gconstpointer aa, gconstpointer bb)
meillo@0 255 {
meillo@10 256 const mxip_addr *a = (mxip_addr *) aa;
meillo@10 257 const mxip_addr *b = (mxip_addr *) bb;
meillo@0 258
meillo@10 259 if (a->pref == b->pref)
meillo@10 260 return a->ip - b->ip;
meillo@10 261 else
meillo@10 262 return a->pref - b->pref;
meillo@0 263 }
meillo@0 264
meillo@10 265 GList*
meillo@10 266 resolve_dns_mx(GList * list, gchar * domain)
meillo@0 267 {
meillo@10 268 GList *node;
meillo@10 269 int ret;
meillo@10 270 int cnt = 0;
meillo@0 271
meillo@10 272 DEBUG(5) debugf("DNS: resolve_dns_mx entered\n");
meillo@0 273
meillo@10 274 if (dns_resolve(domain, T_MX, TRUE) == 0) {
meillo@10 275 GList *node_next;
meillo@10 276 mxip_addr mxip;
meillo@10 277 while ((ret = dns_getmx(&(mxip.pref))) != 2) {
meillo@10 278 if (ret == 1) {
meillo@10 279 mxip.name = g_strdup(name);
meillo@10 280 mxip.ip = rand();
meillo@10 281 list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
meillo@10 282 cnt++;
meillo@10 283 }
meillo@10 284 }
meillo@0 285
meillo@10 286 DEBUG(5) debugf("DNS: found %d mx records\n", cnt);
meillo@0 287
meillo@10 288 /* to randomize sequences with equal pref values,
meillo@10 289 we temporarily 'misused' the ip field and
meillo@10 290 put a random number in it as a secondary sort key.
meillo@10 291 */
meillo@10 292 list = g_list_sort(list, _mx_sort_func);
meillo@0 293
meillo@10 294 /* CNAME resolving has to be added as well. */
meillo@0 295
meillo@10 296 for (node = g_list_first(list); node != NULL; node = node_next) {
meillo@0 297
meillo@10 298 mxip_addr *p_mxip = (mxip_addr *) (node->data);
meillo@10 299 node_next = g_list_next(node);
meillo@0 300
meillo@10 301 if (dns_look_ip(p_mxip->name, &(p_mxip->ip)) != 0) {
meillo@10 302 DEBUG(1) debugf("DNS: could not resolve target of mx %s\n", p_mxip->name);
meillo@10 303 list = g_list_remove_link(list, node);
meillo@10 304 g_free(node->data);
meillo@10 305 g_list_free_1(node);
meillo@10 306 }
meillo@10 307 }
meillo@10 308 }
meillo@10 309 return list;
meillo@0 310 }
meillo@0 311
meillo@0 312 #endif
meillo@0 313
meillo@0 314 /* now something completely different... */
meillo@0 315
meillo@10 316 GList*
meillo@10 317 resolve_byname(GList * list, gchar * domain)
meillo@0 318 {
meillo@10 319 struct hostent *hent;
meillo@0 320
meillo@10 321 DEBUG(5) debugf("DNS: resolve_byname entered\n");
meillo@0 322
meillo@10 323 if ((hent = gethostbyname(domain))) {
meillo@10 324 char *haddr;
meillo@10 325 int i = 0;
meillo@10 326 while ((haddr = hent->h_addr_list[i++])) {
meillo@10 327 mxip_addr mxip;
meillo@10 328 mxip.ip = *(guint32 *) (haddr);
meillo@10 329 mxip.pref = 0;
meillo@10 330 mxip.name = g_strdup(hent->h_name);
meillo@10 331 list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
meillo@10 332 }
meillo@10 333 }
meillo@10 334 return list;
meillo@0 335 }
meillo@0 336
meillo@0 337 #ifdef RESOLV_TEST
meillo@10 338 int
meillo@10 339 main(int argc, char *argv[])
meillo@0 340 {
meillo@10 341 GList *addr_list = NULL, *node;
meillo@0 342
meillo@10 343 g_print("starting res_init()\n");
meillo@10 344 g_print("retrans = %d, retry = %d\n", _res.retrans, _res.retry);
meillo@10 345 if (res_init() == 0) {
meillo@10 346 addr_list = resolve_dns_a(NULL, argv[1]);
meillo@10 347 g_print("A:\n");
meillo@10 348 foreach(addr_list, node) {
meillo@10 349 mxip_addr *p_mxip = (mxip_addr *) (node->data);
meillo@10 350 printf("name = %s\n IP = %s\n", p_mxip->name, inet_ntoa(*(struct in_addr *) &(p_mxip->ip)));
meillo@10 351 }
meillo@10 352 addr_list = resolve_dns_mx(NULL, argv[1]);
meillo@10 353 g_print("MX:\n");
meillo@10 354 foreach(addr_list, node) {
meillo@10 355 mxip_addr *p_mxip = (mxip_addr *) (node->data);
meillo@15 356 printf("name = %s\n IP = %s pref = %d\n", p_mxip->name,
meillo@15 357 inet_ntoa(*(struct in_addr *) &(p_mxip->ip)), p_mxip->pref);
meillo@10 358 }
meillo@10 359 {
meillo@10 360 guint32 ip;
meillo@10 361 dns_look_ip(argv[1], &ip);
meillo@10 362 printf("dns_look_ip: %s\n", inet_ntoa(*((struct in_addr *) (&ip))));
meillo@10 363 }
meillo@10 364 } else
meillo@10 365 printf("res_init() failed.\n");
meillo@0 366 }
meillo@0 367 #endif