masqmail-0.2: 9fb7ddbaf129 src/lookup.c

masqmail-0.2

view src/lookup.c @ 12:9fb7ddbaf129

removed noop-code; some beautifying

author	meillo@marmaro.de
date	Wed, 29 Oct 2008 16:34:13 +0100
parents	08114f7dcc23
children	f671821d8222

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 */

18 #include <sys/types.h>

19 #include <netinet/in.h>

20 #include <arpa/nameser.h>

21 #include <resolv.h>

23 #include "masqmail.h"

25 #ifdef RESOLV_TEST

27 #undef DEBUG

28 #define DEBUG(x) if(x > 0)

30 #define debugf g_print

31 #endif

33 #ifdef ENABLE_RESOLVER

35 static union {

36 HEADER hdr;

37 unsigned char buf[PACKETSZ];

38 } response;

39 static unsigned char *resp_end;

40 static unsigned char *resp_pos;

42 static int num_answers;

43 static char name[MAX_DNSNAME];

45 unsigned short rr_type;

46 unsigned short rr_dlen;

48 static unsigned short

49 getshort(unsigned char *c)

50 {

51 unsigned short u;

52 u = c[0];

53 return (u << 8) + c[1];

54 }

56 static int

57 dns_resolve(char *domain, int type, gboolean do_search)

58 {

59 int n;

60 int i;

62 int resp_len;

63 /*errno = 0; */

65 /*

66 if (!stralloc_copy(&glue,domain)) return DNS_MEM;

67 if (!stralloc_0(&glue)) return DNS_MEM;

68 */

70 // resp_len = res_query(domain, C_IN, type, response.buf, sizeof(response));

71 DEBUG(5) debugf("DNS: before res_search()\n");

72 if (do_search)

73 resp_len = res_search(domain, C_IN, type, response.buf, sizeof(response));

74 else

75 resp_len = res_query(domain, C_IN, type, response.buf, sizeof(response));

76 DEBUG(5) debugf("DBG: after res_search()\n");

78 if (resp_len <= 0) {

79 /*

80 if (errno == ECONNREFUSED) return DNS_SOFT;

81 if (h_errno == TRY_AGAIN) return DNS_SOFT;

82 return DNS_HARD;

83 */

84 return -1;

85 }

86 if (resp_len >= sizeof(response))

87 resp_len = sizeof(response);

89 resp_end = response.buf + resp_len;

90 resp_pos = response.buf + sizeof(HEADER);

91 n = ntohs(response.hdr.qdcount);

93 while (n-- > 0) {

94 i = dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME);

95 if (i < 0)

96 return -1;

97 DEBUG(5) debugf("DBG: resolve name = %s\n", name);

98 resp_pos += i;

99 i = resp_end - resp_pos;

100 if (i < QFIXEDSZ)

101 return -1;

102 resp_pos += QFIXEDSZ;

103 }

104 num_answers = ntohs(response.hdr.ancount);

105

106 return 0;

107 }

108

109 static int

110 dns_next()

111 {

112 int i;

113

114 if (num_answers <= 0)

115 return 2;

116 num_answers--;

117

118 if (resp_pos == resp_end)

119 return -1; /* soft */

120

121 i = dn_expand(response.buf, resp_end, resp_pos, name, 256);

122 if (i < 0)

123 return -1; /* soft */

124 resp_pos += i;

125

126 i = resp_end - resp_pos;

127 if (i < 4 + 3 * 2)

128 return -1; /* soft */

129

130 rr_type = getshort(resp_pos);

131 rr_dlen = getshort(resp_pos + 8);

132 resp_pos += 10;

133

134 return 0;

135 }

136

137 static int

138 dns_getip(guint32 * ip)

139 {

140 int ret;

141

142 if ((ret = dns_next()))

143 return ret;

144

145 if (rr_type == T_A) {

146 if (rr_dlen < 4)

147 return -1; /* soft */

148 *ip = *(guint32 *) (resp_pos);

149 DEBUG(5) debugf("DNS: dns_getip(): ip = %s\n", inet_ntoa(*(struct in_addr *) ip));

150 resp_pos += rr_dlen;

151

152 return 1;

153 }

154 resp_pos += rr_dlen;

155 return 0;

156 }

157

158 static int

159 dns_getmx(int *pref)

160 {

161 int ret;

162

163 if ((ret = dns_next()))

164 return ret;

165

166 if (rr_type == T_MX) {

167 if (rr_dlen < 3)

168 return -1; /* soft */

169

170 *pref = (resp_pos[0] << 8) + resp_pos[1];

171 if (dn_expand(response.buf, resp_end, resp_pos + 2, name, MAX_DNSNAME) < 0)

172 return -1;

173

174 resp_pos += rr_dlen;

175

176 return 1;

177 }

178 resp_pos += rr_dlen;

179 return 0;

180 }

181

182 /*

183 static int

184 dns_getname(int type)

185 {

186 int ret;

187

188 if((ret = dns_next())) return ret;

189

190 if (rr_type == type){

191 if (dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME) < 0)

192 return -1;

193

194 resp_pos += rr_dlen;

195

196 return 1;

197 }

198 resp_pos += rr_dlen;

199 return 0;

200 }

201 */

202

203 static int

204 dns_look_ip(gchar * domain, guint32 * ip)

205 {

206 gchar *n = domain;

207

208 while (TRUE) {

209 if (dns_resolve(n, T_A, FALSE) == 0) {

210 dns_next();

211 if (rr_type == T_A) {

212 if (rr_dlen < 4)

213 return -1; /* soft */

214 *ip = *(guint32 *) (resp_pos);

215

216 DEBUG(5) debugf("DNS: dns_look_ip(): ip = %s\n", inet_ntoa(*(struct in_addr *) ip));

217

218 resp_pos += rr_dlen;

219 return 0;

220 } else if (rr_type == T_CNAME) {

221 if (dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME) < 0)

222 return -1;

223

224 DEBUG(5) debugf("DNS: (CNAME) dns_look_ip(): name = %s\n", name);

225

226 resp_pos += rr_dlen;

227 n = name;

228 } else

229 return -1;

230 } else

231 return -1;

232 }

233 }

234

235 GList*

236 resolve_dns_a(GList * list, gchar * domain)

237 {

238 int ret;

239

240 DEBUG(5) debugf("DNS: resolve_dns_a entered\n");

241

242 if (dns_resolve(domain, T_A, TRUE) == 0) {

243 mxip_addr mxip;

244 while ((ret = dns_getip(&(mxip.ip))) != 2) {

245 if (ret == 1) {

246 mxip.name = g_strdup(name);

247 mxip.pref = 0;

248 list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));

249 }

250 }

251 }

252 return list;

253 }

254

255 static gint

256 _mx_sort_func(gconstpointer aa, gconstpointer bb)

257 {

258 const mxip_addr *a = (mxip_addr *) aa;

259 const mxip_addr *b = (mxip_addr *) bb;

260

261 if (a->pref == b->pref)

262 return a->ip - b->ip;

263 else

264 return a->pref - b->pref;

265 }

266

267 GList*

268 resolve_dns_mx(GList * list, gchar * domain)

269 {

270 GList *node;

271 int ret;

272 int cnt = 0;

273

274 DEBUG(5) debugf("DNS: resolve_dns_mx entered\n");

275

276 if (dns_resolve(domain, T_MX, TRUE) == 0) {

277 GList *node_next;

278 mxip_addr mxip;

279 while ((ret = dns_getmx(&(mxip.pref))) != 2) {

280 if (ret == 1) {

281 mxip.name = g_strdup(name);

282 mxip.ip = rand();

283 list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));

284 cnt++;

285 }

286 }

287

288 DEBUG(5) debugf("DNS: found %d mx records\n", cnt);

289

290 /* to randomize sequences with equal pref values,

291 we temporarily 'misused' the ip field and

292 put a random number in it as a secondary sort key.

293 */

294 list = g_list_sort(list, _mx_sort_func);

295

296 /* CNAME resolving has to be added as well. */

297

298 for (node = g_list_first(list); node != NULL; node = node_next) {

299

300 mxip_addr *p_mxip = (mxip_addr *) (node->data);

301 node_next = g_list_next(node);

302

303 if (dns_look_ip(p_mxip->name, &(p_mxip->ip)) != 0) {

304 DEBUG(1) debugf("DNS: could not resolve target of mx %s\n", p_mxip->name);

305 list = g_list_remove_link(list, node);

306 g_free(node->data);

307 g_list_free_1(node);

308 }

309 }

310 }

311 return list;

312 }

313

314 #endif

315

316 /* now something completely different... */

317

318 GList*

319 resolve_byname(GList * list, gchar * domain)

320 {

321 struct hostent *hent;

322

323 DEBUG(5) debugf("DNS: resolve_byname entered\n");

324

325 if ((hent = gethostbyname(domain))) {

326 char *haddr;

327 int i = 0;

328 while ((haddr = hent->h_addr_list[i++])) {

329 mxip_addr mxip;

330 mxip.ip = *(guint32 *) (haddr);

331 mxip.pref = 0;

332 mxip.name = g_strdup(hent->h_name);

333 list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));

334 }

335 }

336 return list;

337 }

338

339 #ifdef RESOLV_TEST

340 int

341 main(int argc, char *argv[])

342 {

343 GList *addr_list = NULL, *node;

344

345 g_print("starting res_init()\n");

346

347 g_print("retrans = %d, retry = %d\n", _res.retrans, _res.retry);

348

349 if (res_init() == 0) {

350

351 addr_list = resolve_dns_a(NULL, argv[1]);

352 g_print("A:\n");

353

354 foreach(addr_list, node) {

355 mxip_addr *p_mxip = (mxip_addr *) (node->data);

356

357 printf("name = %s\n IP = %s\n", p_mxip->name, inet_ntoa(*(struct in_addr *) &(p_mxip->ip)));

358 }

359 addr_list = resolve_dns_mx(NULL, argv[1]);

360 g_print("MX:\n");

361

362 foreach(addr_list, node) {

363 mxip_addr *p_mxip = (mxip_addr *) (node->data);

364

365 printf("name = %s\n IP = %s pref = %d\n", p_mxip->name, inet_ntoa(*(struct in_addr *) &(p_mxip->ip)), p_mxip->pref);

366 }

367 {

368 guint32 ip;

369 dns_look_ip(argv[1], &ip);

370 printf("dns_look_ip: %s\n", inet_ntoa(*((struct in_addr *) (&ip))));

371 }

372 } else

373 printf("res_init() failed.\n");

374

375 }

376 #endif