1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/lookup.c	Fri Sep 26 17:05:23 2008 +0200
     1.3 @@ -0,0 +1,376 @@
     1.4 +/* MasqMail Copyright (C) Oliver Kurth,
     1.5 + *
     1.6 + * This program is free software; you can redistribute it and/or modify
     1.7 + * it under the terms of the GNU General Public License as published by
     1.8 + * the Free Software Foundation; either version 2 of the License, or
     1.9 + * (at your option) any later version.
    1.10 + * 
    1.11 + * This program is distributed in the hope that it will be useful,
    1.12 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    1.13 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    1.14 + * GNU General Public License for more details.
    1.15 + *
    1.16 + * You should have received a copy of the GNU General Public License
    1.17 + * along with this program; if not, write to the Free Software
    1.18 + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
    1.19 + */
    1.20 +
    1.21 +#include <sys/types.h>
    1.22 +#include <netinet/in.h>
    1.23 +#include <arpa/nameser.h>
    1.24 +#include <resolv.h>
    1.25 +
    1.26 +#include "masqmail.h"
    1.27 +
    1.28 +#ifdef RESOLV_TEST
    1.29 +
    1.30 +#undef DEBUG
    1.31 +#define DEBUG(x) if(x > 0)
    1.32 +
    1.33 +#define debugf g_print
    1.34 +#endif
    1.35 +
    1.36 +#ifdef ENABLE_RESOLVER
    1.37 +
    1.38 +static union {
    1.39 +  HEADER hdr;
    1.40 +  unsigned char buf[PACKETSZ];
    1.41 +} response;
    1.42 +static unsigned char *resp_end;
    1.43 +static unsigned char *resp_pos;
    1.44 +
    1.45 +static int num_answers;
    1.46 +static char name[MAX_DNSNAME];
    1.47 +
    1.48 +unsigned short rr_type;
    1.49 +unsigned short rr_dlen;
    1.50 +
    1.51 +static
    1.52 +unsigned short getshort(unsigned char *c)
    1.53 +{
    1.54 +  unsigned short u;
    1.55 +  u = c[0];
    1.56 +  return (u << 8) + c[1];
    1.57 +}
    1.58 +
    1.59 +static
    1.60 +int dns_resolve(char *domain, int type, gboolean do_search)
    1.61 +{
    1.62 +  int n;
    1.63 +  int i;
    1.64 +
    1.65 +  int resp_len;
    1.66 +  /*errno = 0;*/
    1.67 +
    1.68 +  /*
    1.69 +  if (!stralloc_copy(&glue,domain)) return DNS_MEM;
    1.70 +  if (!stralloc_0(&glue)) return DNS_MEM;
    1.71 +  */
    1.72 +
    1.73 +  //  resp_len = res_query(domain, C_IN, type, response.buf, sizeof(response));
    1.74 +  DEBUG(5) debugf("DNS: before res_search()\n");
    1.75 +  if(do_search)
    1.76 +    resp_len = res_search(domain, C_IN, type, response.buf, sizeof(response));
    1.77 +  else
    1.78 +    resp_len = res_query(domain, C_IN, type, response.buf, sizeof(response));
    1.79 +  DEBUG(5) debugf("DBG: after res_search()\n");
    1.80 +
    1.81 +  if (resp_len <= 0){
    1.82 +    /*
    1.83 +    if (errno == ECONNREFUSED) return DNS_SOFT;
    1.84 +    if (h_errno == TRY_AGAIN) return DNS_SOFT;
    1.85 +    return DNS_HARD;
    1.86 +    */
    1.87 +    return -1;
    1.88 +  }
    1.89 +  if (resp_len >= sizeof(response))
    1.90 +    resp_len = sizeof(response);
    1.91 +
    1.92 +  resp_end = response.buf + resp_len;
    1.93 +  resp_pos = response.buf + sizeof(HEADER);
    1.94 +  n = ntohs(response.hdr.qdcount);
    1.95 +
    1.96 +  while (n-- > 0){
    1.97 +    i = dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME);
    1.98 +    if (i < 0)
    1.99 +      return -1;
   1.100 +    DEBUG(5) debugf("DBG: resolve name = %s\n", name);
   1.101 +    resp_pos += i;
   1.102 +    i = resp_end - resp_pos;
   1.103 +    if (i < QFIXEDSZ)
   1.104 +      return -1;
   1.105 +    resp_pos += QFIXEDSZ;
   1.106 +  }
   1.107 +  num_answers = ntohs(response.hdr.ancount);
   1.108 +
   1.109 +  return 0;
   1.110 +}
   1.111 +
   1.112 +static int dns_next()
   1.113 +{
   1.114 +  int i;
   1.115 +
   1.116 +  if (num_answers <= 0) return 2;
   1.117 +  num_answers--;
   1.118 +
   1.119 +  if (resp_pos == resp_end)
   1.120 +    return -1 /* soft */;
   1.121 +
   1.122 +  i = dn_expand(response.buf, resp_end, resp_pos, name, 256);
   1.123 +  if (i < 0)
   1.124 +    return -1; /* soft */
   1.125 +  resp_pos += i;
   1.126 +
   1.127 +  i = resp_end - resp_pos;
   1.128 +  if (i < 4 + 3 * 2)
   1.129 +    return -1; /* soft */
   1.130 +   
   1.131 +  rr_type = getshort(resp_pos);
   1.132 +  rr_dlen = getshort(resp_pos + 8);
   1.133 +  resp_pos += 10;
   1.134 +
   1.135 +  return 0;
   1.136 +}
   1.137 +
   1.138 +static
   1.139 +int dns_getip(guint32 *ip)
   1.140 +{
   1.141 +  int ret;
   1.142 +
   1.143 +  if((ret = dns_next())) return ret;
   1.144 +
   1.145 +  if (rr_type == T_A){
   1.146 +    if (rr_dlen < 4)
   1.147 +      return -1; /* soft */
   1.148 +    *ip = *(guint32 *)(resp_pos);
   1.149 +    DEBUG(5) debugf("DNS: dns_getip(): ip = %s\n", inet_ntoa(*(struct in_addr*)ip));
   1.150 +    resp_pos += rr_dlen;
   1.151 +
   1.152 +    return 1;
   1.153 +  }
   1.154 +  resp_pos += rr_dlen;
   1.155 +  return 0;
   1.156 +}
   1.157 +
   1.158 +static
   1.159 +int dns_getmx(int *pref)
   1.160 +{
   1.161 +  int ret;
   1.162 +
   1.163 +  if((ret = dns_next())) return ret;
   1.164 +
   1.165 +  if (rr_type == T_MX){
   1.166 +    if (rr_dlen < 3)
   1.167 +      return -1; /* soft */
   1.168 +
   1.169 +    *pref = (resp_pos[0] << 8) + resp_pos[1];
   1.170 +    if (dn_expand(response.buf, resp_end, resp_pos + 2, name, MAX_DNSNAME) < 0)
   1.171 +      return -1;
   1.172 +   
   1.173 +    resp_pos += rr_dlen;
   1.174 +
   1.175 +    return 1;
   1.176 +  }
   1.177 +  resp_pos += rr_dlen;
   1.178 +  return 0;
   1.179 +}
   1.180 +
   1.181 +/*
   1.182 +static
   1.183 +int dns_getname(int type)
   1.184 +{
   1.185 +  int ret;
   1.186 +
   1.187 +  if((ret = dns_next())) return ret;
   1.188 +
   1.189 +  if (rr_type == type){
   1.190 +    if (dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME) < 0)
   1.191 +      return -1;
   1.192 +   
   1.193 +    resp_pos += rr_dlen;
   1.194 +
   1.195 +    return 1;
   1.196 +  }
   1.197 +  resp_pos += rr_dlen;
   1.198 +  return 0;
   1.199 +}
   1.200 +*/
   1.201 +
   1.202 +static
   1.203 +int dns_look_ip(gchar *domain, guint32 *ip)
   1.204 +{
   1.205 +  gchar *n = domain;
   1.206 +
   1.207 +  while(TRUE){
   1.208 +    if(dns_resolve(n, T_A, FALSE) == 0){
   1.209 +      dns_next();
   1.210 +      if(rr_type == T_A){
   1.211 +	if (rr_dlen < 4)
   1.212 +	  return -1; /* soft */
   1.213 +	*ip = *(guint32 *)(resp_pos);
   1.214 +	
   1.215 +	DEBUG(5) debugf("DNS: dns_look_ip(): ip = %s\n",
   1.216 +			inet_ntoa(*(struct in_addr*)ip));
   1.217 +	
   1.218 +	resp_pos += rr_dlen;
   1.219 +	return 0;
   1.220 +      }else if(rr_type == T_CNAME){
   1.221 +	if (dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME) < 0)
   1.222 +	  return -1;
   1.223 +
   1.224 +	DEBUG(5) debugf("DNS: (CNAME) dns_look_ip(): name = %s\n", name);
   1.225 +	
   1.226 +	resp_pos += rr_dlen;
   1.227 +	n = name;
   1.228 +      }else
   1.229 +	return -1;
   1.230 +    }else
   1.231 +      return -1;
   1.232 +  }
   1.233 +}
   1.234 +
   1.235 +GList *resolve_dns_a(GList *list, gchar *domain)
   1.236 +{
   1.237 +  int ret;
   1.238 +
   1.239 +  DEBUG(5) debugf("DNS: resolve_dns_a entered\n");
   1.240 +
   1.241 +  if(dns_resolve(domain, T_A, TRUE) == 0){
   1.242 +    mxip_addr mxip;
   1.243 +    while((ret = dns_getip(&(mxip.ip))) != 2){
   1.244 +      if(ret == 1){
   1.245 +	mxip.name = g_strdup(name);
   1.246 +	mxip.pref = 0;
   1.247 +	list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
   1.248 +      }
   1.249 +    }
   1.250 +  }
   1.251 +  return list;
   1.252 +}
   1.253 +
   1.254 +static
   1.255 +gint _mx_sort_func(gconstpointer aa, gconstpointer bb)
   1.256 +{
   1.257 +  const mxip_addr *a = (mxip_addr *)aa;
   1.258 +  const mxip_addr *b = (mxip_addr *)bb;
   1.259 +
   1.260 +  if(a->pref == b->pref)
   1.261 +    return a->ip - b->ip;
   1.262 +  else
   1.263 +    return a->pref - b->pref;
   1.264 +}
   1.265 +
   1.266 +GList *resolve_dns_mx(GList *list, gchar *domain)
   1.267 +{
   1.268 +  GList *node;
   1.269 +  int ret;
   1.270 +  int cnt = 0;
   1.271 +
   1.272 +  DEBUG(5) debugf("DNS: resolve_dns_mx entered\n");
   1.273 +
   1.274 +  if(dns_resolve(domain, T_MX, TRUE) == 0){
   1.275 +    GList *node_next;
   1.276 +    mxip_addr mxip;
   1.277 +    while((ret = dns_getmx(&(mxip.pref))) != 2){
   1.278 +      if(ret == 1){
   1.279 +	mxip.name = g_strdup(name);
   1.280 +	mxip.ip = rand();
   1.281 +	list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
   1.282 +	cnt++;
   1.283 +      }
   1.284 +    }
   1.285 +
   1.286 +    DEBUG(5) debugf("DNS: found %d mx records\n", cnt);
   1.287 +
   1.288 +    /* to randomize sequences with equal pref values,
   1.289 +       we temporarily 'misused' the ip field and
   1.290 +       put a random number in it as a secondary sort key.
   1.291 +    */
   1.292 +    list = g_list_sort(list, _mx_sort_func);
   1.293 +
   1.294 +    /* CNAME resolving has to be added as well. */
   1.295 +
   1.296 +    for(node = g_list_first(list);
   1.297 +	node != NULL;
   1.298 +	node = node_next){
   1.299 +
   1.300 +      mxip_addr *p_mxip = (mxip_addr *)(node->data);
   1.301 +      node_next = g_list_next(node);
   1.302 +
   1.303 +      if(dns_look_ip(p_mxip->name, &(p_mxip->ip)) != 0){
   1.304 +	DEBUG(1) debugf("DNS: could not resolve target of mx %s\n", p_mxip->name);
   1.305 +	list = g_list_remove_link(list, node);
   1.306 +	g_free(node->data);
   1.307 +	g_list_free_1(node);
   1.308 +      }
   1.309 +    }
   1.310 +  }
   1.311 +  return list;
   1.312 +}
   1.313 +
   1.314 +#endif
   1.315 +
   1.316 +/* now something completely different... */
   1.317 +
   1.318 +GList *resolve_byname(GList *list, gchar *domain)
   1.319 +{
   1.320 +  struct hostent *hent;
   1.321 +
   1.322 +  DEBUG(5) debugf("DNS: resolve_byname entered\n");
   1.323 +
   1.324 +  if((hent = gethostbyname(domain))){
   1.325 +    char *haddr;
   1.326 +    int i = 0;
   1.327 +    while((haddr = hent->h_addr_list[i++])){
   1.328 +      mxip_addr mxip;
   1.329 +      mxip.ip = *(guint32 *)(haddr);
   1.330 +      mxip.pref = 0;
   1.331 +      mxip.name = g_strdup(hent->h_name);
   1.332 +      list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
   1.333 +    }
   1.334 +  }
   1.335 +  return list;
   1.336 +}
   1.337 +
   1.338 +#ifdef RESOLV_TEST
   1.339 +int main(int argc, char *argv[])
   1.340 +{
   1.341 +  GList *addr_list = NULL, *node;
   1.342 +
   1.343 +  g_print("starting res_init()\n");
   1.344 +
   1.345 +  g_print("retrans = %d, retry = %d\n", _res.retrans, _res.retry);
   1.346 +
   1.347 +  if(res_init() == 0){
   1.348 +    
   1.349 +    addr_list = resolve_dns_a(NULL, argv[1]);
   1.350 +    g_print("A:\n");
   1.351 +
   1.352 +    foreach(addr_list, node){
   1.353 +      mxip_addr *p_mxip = (mxip_addr *)(node->data);
   1.354 +    
   1.355 +      printf("name = %s\n IP = %s\n",
   1.356 +	     p_mxip->name,
   1.357 +	     inet_ntoa(*(struct in_addr *)&(p_mxip->ip)));
   1.358 +    }
   1.359 +    addr_list = resolve_dns_mx(NULL, argv[1]);
   1.360 +    g_print("MX:\n");
   1.361 +
   1.362 +    foreach(addr_list, node){
   1.363 +      mxip_addr *p_mxip = (mxip_addr *)(node->data);
   1.364 +    
   1.365 +      printf("name = %s\n IP = %s pref = %d\n",
   1.366 +	     p_mxip->name,
   1.367 +	     inet_ntoa(*(struct in_addr *)&(p_mxip->ip)),
   1.368 +	     p_mxip->pref);
   1.369 +    }
   1.370 +    {
   1.371 +      guint32 ip;
   1.372 +      dns_look_ip(argv[1], &ip);
   1.373 +      printf("dns_look_ip: %s\n", inet_ntoa(*((struct in_addr *)(&ip))));
   1.374 +    }
   1.375 +  }else
   1.376 +    printf("res_init() failed.\n");
   1.377 +  
   1.378 +}
   1.379 +#endif