masqmail

annotate src/lookup.c @ 387:a408411ff8df

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Added a glob-pattern aliasing facility. One use-case is virtual hosting another catch-all maildrops, but you may use it as a more flexible aliasing mechanism as well.
author markus schnalke <meillo@marmaro.de>
date Sat, 18 Feb 2012 12:35:12 +0100
parents 41958685480d
children
rev   line source
meillo@367 1 /*
meillo@367 2 ** MasqMail
meillo@367 3 ** Copyright (C) Oliver Kurth
meillo@367 4 ** Copyright (C) markus schnalke <meillo@marmaro.de>
meillo@367 5 **
meillo@367 6 ** This program is free software; you can redistribute it and/or modify
meillo@367 7 ** it under the terms of the GNU General Public License as published by
meillo@367 8 ** the Free Software Foundation; either version 2 of the License, or
meillo@367 9 ** (at your option) any later version.
meillo@367 10 **
meillo@367 11 ** This program is distributed in the hope that it will be useful,
meillo@367 12 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
meillo@367 13 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
meillo@367 14 ** GNU General Public License for more details.
meillo@367 15 **
meillo@367 16 ** You should have received a copy of the GNU General Public License
meillo@367 17 ** along with this program; if not, write to the Free Software
meillo@367 18 ** Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
meillo@367 19 */
meillo@0 20
meillo@0 21 #include <sys/types.h>
meillo@0 22 #include <netinet/in.h>
meillo@0 23 #include <arpa/nameser.h>
meillo@0 24 #include <resolv.h>
meillo@0 25
meillo@0 26 #include "masqmail.h"
meillo@0 27
meillo@0 28
meillo@0 29 #ifdef ENABLE_RESOLVER
meillo@0 30
meillo@0 31 static union {
meillo@10 32 HEADER hdr;
meillo@10 33 unsigned char buf[PACKETSZ];
meillo@0 34 } response;
meillo@0 35 static unsigned char *resp_end;
meillo@0 36 static unsigned char *resp_pos;
meillo@0 37
meillo@0 38 static int num_answers;
meillo@0 39 static char name[MAX_DNSNAME];
meillo@0 40
meillo@0 41 unsigned short rr_type;
meillo@0 42 unsigned short rr_dlen;
meillo@0 43
meillo@10 44 static unsigned short
meillo@10 45 getshort(unsigned char *c)
meillo@0 46 {
meillo@10 47 unsigned short u;
meillo@10 48 u = c[0];
meillo@10 49 return (u << 8) + c[1];
meillo@0 50 }
meillo@0 51
meillo@10 52 static int
meillo@10 53 dns_resolve(char *domain, int type, gboolean do_search)
meillo@0 54 {
meillo@10 55 int n;
meillo@10 56 int i;
meillo@207 57 int resp_len;
meillo@0 58
meillo@10 59 DEBUG(5) debugf("DNS: before res_search()\n");
meillo@10 60 if (do_search)
meillo@10 61 resp_len = res_search(domain, C_IN, type, response.buf, sizeof(response));
meillo@10 62 else
meillo@10 63 resp_len = res_query(domain, C_IN, type, response.buf, sizeof(response));
meillo@10 64 DEBUG(5) debugf("DBG: after res_search()\n");
meillo@0 65
meillo@10 66 if (resp_len <= 0) {
meillo@10 67 /*
meillo@367 68 ** if (errno == ECONNREFUSED) return DNS_SOFT;
meillo@367 69 ** if (h_errno == TRY_AGAIN) return DNS_SOFT;
meillo@367 70 ** return DNS_HARD;
meillo@367 71 */
meillo@10 72 return -1;
meillo@10 73 }
meillo@10 74 if (resp_len >= sizeof(response))
meillo@10 75 resp_len = sizeof(response);
meillo@0 76
meillo@10 77 resp_end = response.buf + resp_len;
meillo@10 78 resp_pos = response.buf + sizeof(HEADER);
meillo@10 79 n = ntohs(response.hdr.qdcount);
meillo@0 80
meillo@10 81 while (n-- > 0) {
meillo@10 82 i = dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME);
meillo@10 83 if (i < 0)
meillo@10 84 return -1;
meillo@10 85 DEBUG(5) debugf("DBG: resolve name = %s\n", name);
meillo@10 86 resp_pos += i;
meillo@10 87 i = resp_end - resp_pos;
meillo@10 88 if (i < QFIXEDSZ)
meillo@10 89 return -1;
meillo@10 90 resp_pos += QFIXEDSZ;
meillo@10 91 }
meillo@10 92 num_answers = ntohs(response.hdr.ancount);
meillo@0 93
meillo@10 94 return 0;
meillo@0 95 }
meillo@0 96
meillo@10 97 static int
meillo@10 98 dns_next()
meillo@0 99 {
meillo@10 100 int i;
meillo@0 101
meillo@10 102 if (num_answers <= 0)
meillo@10 103 return 2;
meillo@10 104 num_answers--;
meillo@0 105
meillo@10 106 if (resp_pos == resp_end)
meillo@10 107 return -1; /* soft */
meillo@0 108
meillo@10 109 i = dn_expand(response.buf, resp_end, resp_pos, name, 256);
meillo@10 110 if (i < 0)
meillo@10 111 return -1; /* soft */
meillo@10 112 resp_pos += i;
meillo@0 113
meillo@10 114 i = resp_end - resp_pos;
meillo@10 115 if (i < 4 + 3 * 2)
meillo@10 116 return -1; /* soft */
meillo@0 117
meillo@10 118 rr_type = getshort(resp_pos);
meillo@10 119 rr_dlen = getshort(resp_pos + 8);
meillo@10 120 resp_pos += 10;
meillo@10 121
meillo@10 122 return 0;
meillo@0 123 }
meillo@0 124
meillo@10 125 static int
meillo@366 126 dns_getip(guint32 *ip)
meillo@0 127 {
meillo@10 128 int ret;
meillo@0 129
meillo@10 130 if ((ret = dns_next()))
meillo@10 131 return ret;
meillo@0 132
meillo@10 133 if (rr_type == T_A) {
meillo@10 134 if (rr_dlen < 4)
meillo@10 135 return -1; /* soft */
meillo@10 136 *ip = *(guint32 *) (resp_pos);
meillo@10 137 DEBUG(5) debugf("DNS: dns_getip(): ip = %s\n", inet_ntoa(*(struct in_addr *) ip));
meillo@10 138 resp_pos += rr_dlen;
meillo@0 139
meillo@10 140 return 1;
meillo@10 141 }
meillo@10 142 resp_pos += rr_dlen;
meillo@10 143 return 0;
meillo@0 144 }
meillo@0 145
meillo@10 146 static int
meillo@10 147 dns_getmx(int *pref)
meillo@0 148 {
meillo@10 149 int ret;
meillo@0 150
meillo@10 151 if ((ret = dns_next()))
meillo@10 152 return ret;
meillo@0 153
meillo@10 154 if (rr_type == T_MX) {
meillo@10 155 if (rr_dlen < 3)
meillo@10 156 return -1; /* soft */
meillo@0 157
meillo@10 158 *pref = (resp_pos[0] << 8) + resp_pos[1];
meillo@10 159 if (dn_expand(response.buf, resp_end, resp_pos + 2, name, MAX_DNSNAME) < 0)
meillo@10 160 return -1;
meillo@0 161
meillo@10 162 resp_pos += rr_dlen;
meillo@10 163
meillo@10 164 return 1;
meillo@10 165 }
meillo@10 166 resp_pos += rr_dlen;
meillo@10 167 return 0;
meillo@0 168 }
meillo@0 169
meillo@200 170 int
meillo@366 171 dns_look_ip(gchar *domain, guint32 *ip)
meillo@0 172 {
meillo@10 173 gchar *n = domain;
meillo@0 174
meillo@10 175 while (TRUE) {
meillo@200 176 if (dns_resolve(n, T_A, FALSE) != 0) {
meillo@200 177 return -1;
meillo@200 178 }
meillo@0 179
meillo@200 180 dns_next();
meillo@200 181 if (rr_type == T_A) {
meillo@200 182 if (rr_dlen < 4) {
meillo@200 183 return -1; /* soft */
meillo@200 184 }
meillo@200 185 *ip = *(guint32 *) (resp_pos);
meillo@10 186
meillo@200 187 DEBUG(5) debugf("DNS: dns_look_ip(): ip = %s\n", inet_ntoa(*(struct in_addr *) ip));
meillo@10 188
meillo@200 189 resp_pos += rr_dlen;
meillo@200 190 return 0;
meillo@200 191 } else if (rr_type == T_CNAME) {
meillo@200 192 if (dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME) < 0) {
meillo@200 193 return -1;
meillo@200 194 }
meillo@10 195
meillo@200 196 DEBUG(5) debugf("DNS: (CNAME) dns_look_ip(): name = %s\n", name);
meillo@200 197
meillo@200 198 resp_pos += rr_dlen;
meillo@200 199 n = name;
meillo@200 200 } else {
meillo@10 201 return -1;
meillo@200 202 }
meillo@10 203 }
meillo@0 204 }
meillo@0 205
meillo@10 206 GList*
meillo@366 207 resolve_dns_a(GList *list, gchar *domain)
meillo@0 208 {
meillo@10 209 int ret;
meillo@0 210
meillo@10 211 DEBUG(5) debugf("DNS: resolve_dns_a entered\n");
meillo@0 212
meillo@10 213 if (dns_resolve(domain, T_A, TRUE) == 0) {
meillo@10 214 mxip_addr mxip;
meillo@10 215 while ((ret = dns_getip(&(mxip.ip))) != 2) {
meillo@10 216 if (ret == 1) {
meillo@10 217 mxip.name = g_strdup(name);
meillo@10 218 mxip.pref = 0;
meillo@10 219 list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
meillo@10 220 }
meillo@10 221 }
meillo@10 222 }
meillo@10 223 return list;
meillo@0 224 }
meillo@0 225
meillo@10 226 static gint
meillo@10 227 _mx_sort_func(gconstpointer aa, gconstpointer bb)
meillo@0 228 {
meillo@10 229 const mxip_addr *a = (mxip_addr *) aa;
meillo@10 230 const mxip_addr *b = (mxip_addr *) bb;
meillo@0 231
meillo@10 232 if (a->pref == b->pref)
meillo@10 233 return a->ip - b->ip;
meillo@10 234 else
meillo@10 235 return a->pref - b->pref;
meillo@0 236 }
meillo@0 237
meillo@10 238 GList*
meillo@366 239 resolve_dns_mx(GList *list, gchar *domain)
meillo@0 240 {
meillo@10 241 GList *node;
meillo@10 242 int ret;
meillo@10 243 int cnt = 0;
meillo@0 244
meillo@10 245 DEBUG(5) debugf("DNS: resolve_dns_mx entered\n");
meillo@0 246
meillo@10 247 if (dns_resolve(domain, T_MX, TRUE) == 0) {
meillo@10 248 GList *node_next;
meillo@10 249 mxip_addr mxip;
meillo@10 250 while ((ret = dns_getmx(&(mxip.pref))) != 2) {
meillo@10 251 if (ret == 1) {
meillo@10 252 mxip.name = g_strdup(name);
meillo@10 253 mxip.ip = rand();
meillo@10 254 list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
meillo@10 255 cnt++;
meillo@10 256 }
meillo@10 257 }
meillo@0 258
meillo@10 259 DEBUG(5) debugf("DNS: found %d mx records\n", cnt);
meillo@0 260
meillo@367 261 /*
meillo@367 262 ** to randomize sequences with equal pref values,
meillo@367 263 ** we temporarily 'misused' the ip field and
meillo@367 264 ** put a random number in it as a secondary sort key.
meillo@367 265 */
meillo@10 266 list = g_list_sort(list, _mx_sort_func);
meillo@0 267
meillo@10 268 /* CNAME resolving has to be added as well. */
meillo@0 269
meillo@10 270 for (node = g_list_first(list); node != NULL; node = node_next) {
meillo@0 271
meillo@10 272 mxip_addr *p_mxip = (mxip_addr *) (node->data);
meillo@10 273 node_next = g_list_next(node);
meillo@0 274
meillo@10 275 if (dns_look_ip(p_mxip->name, &(p_mxip->ip)) != 0) {
meillo@10 276 DEBUG(1) debugf("DNS: could not resolve target of mx %s\n", p_mxip->name);
meillo@10 277 list = g_list_remove_link(list, node);
meillo@10 278 g_free(node->data);
meillo@10 279 g_list_free_1(node);
meillo@10 280 }
meillo@10 281 }
meillo@10 282 }
meillo@10 283 return list;
meillo@0 284 }
meillo@0 285
meillo@0 286 #endif
meillo@0 287
meillo@0 288 /* now something completely different... */
meillo@0 289
meillo@10 290 GList*
meillo@366 291 resolve_byname(GList *list, gchar *domain)
meillo@0 292 {
meillo@10 293 struct hostent *hent;
meillo@0 294
meillo@10 295 DEBUG(5) debugf("DNS: resolve_byname entered\n");
meillo@0 296
meillo@10 297 if ((hent = gethostbyname(domain))) {
meillo@10 298 char *haddr;
meillo@10 299 int i = 0;
meillo@10 300 while ((haddr = hent->h_addr_list[i++])) {
meillo@10 301 mxip_addr mxip;
meillo@10 302 mxip.ip = *(guint32 *) (haddr);
meillo@10 303 mxip.pref = 0;
meillo@10 304 mxip.name = g_strdup(hent->h_name);
meillo@10 305 list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
meillo@10 306 }
meillo@10 307 }
meillo@10 308 return list;
meillo@0 309 }