--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/lookup.c	Fri Sep 26 17:05:23 2008 +0200
@@ -0,0 +1,376 @@
+/* MasqMail Copyright (C) Oliver Kurth,
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
+
+#include "masqmail.h"
+
+#ifdef RESOLV_TEST
+
+#undef DEBUG
+#define DEBUG(x) if(x > 0)
+
+#define debugf g_print
+#endif
+
+#ifdef ENABLE_RESOLVER
+
+static union {
+  HEADER hdr;
+  unsigned char buf[PACKETSZ];
+} response;
+static unsigned char *resp_end;
+static unsigned char *resp_pos;
+
+static int num_answers;
+static char name[MAX_DNSNAME];
+
+unsigned short rr_type;
+unsigned short rr_dlen;
+
+static
+unsigned short getshort(unsigned char *c)
+{
+  unsigned short u;
+  u = c[0];
+  return (u << 8) + c[1];
+}
+
+static
+int dns_resolve(char *domain, int type, gboolean do_search)
+{
+  int n;
+  int i;
+
+  int resp_len;
+  /*errno = 0;*/
+
+  /*
+  if (!stralloc_copy(&glue,domain)) return DNS_MEM;
+  if (!stralloc_0(&glue)) return DNS_MEM;
+  */
+
+  //  resp_len = res_query(domain, C_IN, type, response.buf, sizeof(response));
+  DEBUG(5) debugf("DNS: before res_search()\n");
+  if(do_search)
+    resp_len = res_search(domain, C_IN, type, response.buf, sizeof(response));
+  else
+    resp_len = res_query(domain, C_IN, type, response.buf, sizeof(response));
+  DEBUG(5) debugf("DBG: after res_search()\n");
+
+  if (resp_len <= 0){
+    /*
+    if (errno == ECONNREFUSED) return DNS_SOFT;
+    if (h_errno == TRY_AGAIN) return DNS_SOFT;
+    return DNS_HARD;
+    */
+    return -1;
+  }
+  if (resp_len >= sizeof(response))
+    resp_len = sizeof(response);
+
+  resp_end = response.buf + resp_len;
+  resp_pos = response.buf + sizeof(HEADER);
+  n = ntohs(response.hdr.qdcount);
+
+  while (n-- > 0){
+    i = dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME);
+    if (i < 0)
+      return -1;
+    DEBUG(5) debugf("DBG: resolve name = %s\n", name);
+    resp_pos += i;
+    i = resp_end - resp_pos;
+    if (i < QFIXEDSZ)
+      return -1;
+    resp_pos += QFIXEDSZ;
+  }
+  num_answers = ntohs(response.hdr.ancount);
+
+  return 0;
+}
+
+static int dns_next()
+{
+  int i;
+
+  if (num_answers <= 0) return 2;
+  num_answers--;
+
+  if (resp_pos == resp_end)
+    return -1 /* soft */;
+
+  i = dn_expand(response.buf, resp_end, resp_pos, name, 256);
+  if (i < 0)
+    return -1; /* soft */
+  resp_pos += i;
+
+  i = resp_end - resp_pos;
+  if (i < 4 + 3 * 2)
+    return -1; /* soft */
+   
+  rr_type = getshort(resp_pos);
+  rr_dlen = getshort(resp_pos + 8);
+  resp_pos += 10;
+
+  return 0;
+}
+
+static
+int dns_getip(guint32 *ip)
+{
+  int ret;
+
+  if((ret = dns_next())) return ret;
+
+  if (rr_type == T_A){
+    if (rr_dlen < 4)
+      return -1; /* soft */
+    *ip = *(guint32 *)(resp_pos);
+    DEBUG(5) debugf("DNS: dns_getip(): ip = %s\n", inet_ntoa(*(struct in_addr*)ip));
+    resp_pos += rr_dlen;
+
+    return 1;
+  }
+  resp_pos += rr_dlen;
+  return 0;
+}
+
+static
+int dns_getmx(int *pref)
+{
+  int ret;
+
+  if((ret = dns_next())) return ret;
+
+  if (rr_type == T_MX){
+    if (rr_dlen < 3)
+      return -1; /* soft */
+
+    *pref = (resp_pos[0] << 8) + resp_pos[1];
+    if (dn_expand(response.buf, resp_end, resp_pos + 2, name, MAX_DNSNAME) < 0)
+      return -1;
+   
+    resp_pos += rr_dlen;
+
+    return 1;
+  }
+  resp_pos += rr_dlen;
+  return 0;
+}
+
+/*
+static
+int dns_getname(int type)
+{
+  int ret;
+
+  if((ret = dns_next())) return ret;
+
+  if (rr_type == type){
+    if (dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME) < 0)
+      return -1;
+   
+    resp_pos += rr_dlen;
+
+    return 1;
+  }
+  resp_pos += rr_dlen;
+  return 0;
+}
+*/
+
+static
+int dns_look_ip(gchar *domain, guint32 *ip)
+{
+  gchar *n = domain;
+
+  while(TRUE){
+    if(dns_resolve(n, T_A, FALSE) == 0){
+      dns_next();
+      if(rr_type == T_A){
+	if (rr_dlen < 4)
+	  return -1; /* soft */
+	*ip = *(guint32 *)(resp_pos);
+	
+	DEBUG(5) debugf("DNS: dns_look_ip(): ip = %s\n",
+			inet_ntoa(*(struct in_addr*)ip));
+	
+	resp_pos += rr_dlen;
+	return 0;
+      }else if(rr_type == T_CNAME){
+	if (dn_expand(response.buf, resp_end, resp_pos, name, MAX_DNSNAME) < 0)
+	  return -1;
+
+	DEBUG(5) debugf("DNS: (CNAME) dns_look_ip(): name = %s\n", name);
+	
+	resp_pos += rr_dlen;
+	n = name;
+      }else
+	return -1;
+    }else
+      return -1;
+  }
+}
+
+GList *resolve_dns_a(GList *list, gchar *domain)
+{
+  int ret;
+
+  DEBUG(5) debugf("DNS: resolve_dns_a entered\n");
+
+  if(dns_resolve(domain, T_A, TRUE) == 0){
+    mxip_addr mxip;
+    while((ret = dns_getip(&(mxip.ip))) != 2){
+      if(ret == 1){
+	mxip.name = g_strdup(name);
+	mxip.pref = 0;
+	list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
+      }
+    }
+  }
+  return list;
+}
+
+static
+gint _mx_sort_func(gconstpointer aa, gconstpointer bb)
+{
+  const mxip_addr *a = (mxip_addr *)aa;
+  const mxip_addr *b = (mxip_addr *)bb;
+
+  if(a->pref == b->pref)
+    return a->ip - b->ip;
+  else
+    return a->pref - b->pref;
+}
+
+GList *resolve_dns_mx(GList *list, gchar *domain)
+{
+  GList *node;
+  int ret;
+  int cnt = 0;
+
+  DEBUG(5) debugf("DNS: resolve_dns_mx entered\n");
+
+  if(dns_resolve(domain, T_MX, TRUE) == 0){
+    GList *node_next;
+    mxip_addr mxip;
+    while((ret = dns_getmx(&(mxip.pref))) != 2){
+      if(ret == 1){
+	mxip.name = g_strdup(name);
+	mxip.ip = rand();
+	list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
+	cnt++;
+      }
+    }
+
+    DEBUG(5) debugf("DNS: found %d mx records\n", cnt);
+
+    /* to randomize sequences with equal pref values,
+       we temporarily 'misused' the ip field and
+       put a random number in it as a secondary sort key.
+    */
+    list = g_list_sort(list, _mx_sort_func);
+
+    /* CNAME resolving has to be added as well. */
+
+    for(node = g_list_first(list);
+	node != NULL;
+	node = node_next){
+
+      mxip_addr *p_mxip = (mxip_addr *)(node->data);
+      node_next = g_list_next(node);
+
+      if(dns_look_ip(p_mxip->name, &(p_mxip->ip)) != 0){
+	DEBUG(1) debugf("DNS: could not resolve target of mx %s\n", p_mxip->name);
+	list = g_list_remove_link(list, node);
+	g_free(node->data);
+	g_list_free_1(node);
+      }
+    }
+  }
+  return list;
+}
+
+#endif
+
+/* now something completely different... */
+
+GList *resolve_byname(GList *list, gchar *domain)
+{
+  struct hostent *hent;
+
+  DEBUG(5) debugf("DNS: resolve_byname entered\n");
+
+  if((hent = gethostbyname(domain))){
+    char *haddr;
+    int i = 0;
+    while((haddr = hent->h_addr_list[i++])){
+      mxip_addr mxip;
+      mxip.ip = *(guint32 *)(haddr);
+      mxip.pref = 0;
+      mxip.name = g_strdup(hent->h_name);
+      list = g_list_append(list, g_memdup(&mxip, sizeof(mxip)));
+    }
+  }
+  return list;
+}
+
+#ifdef RESOLV_TEST
+int main(int argc, char *argv[])
+{
+  GList *addr_list = NULL, *node;
+
+  g_print("starting res_init()\n");
+
+  g_print("retrans = %d, retry = %d\n", _res.retrans, _res.retry);
+
+  if(res_init() == 0){
+    
+    addr_list = resolve_dns_a(NULL, argv[1]);
+    g_print("A:\n");
+
+    foreach(addr_list, node){
+      mxip_addr *p_mxip = (mxip_addr *)(node->data);
+    
+      printf("name = %s\n IP = %s\n",
+	     p_mxip->name,
+	     inet_ntoa(*(struct in_addr *)&(p_mxip->ip)));
+    }
+    addr_list = resolve_dns_mx(NULL, argv[1]);
+    g_print("MX:\n");
+
+    foreach(addr_list, node){
+      mxip_addr *p_mxip = (mxip_addr *)(node->data);
+    
+      printf("name = %s\n IP = %s pref = %d\n",
+	     p_mxip->name,
+	     inet_ntoa(*(struct in_addr *)&(p_mxip->ip)),
+	     p_mxip->pref);
+    }
+    {
+      guint32 ip;
+      dns_look_ip(argv[1], &ip);
+      printf("dns_look_ip: %s\n", inet_ntoa(*((struct in_addr *)(&ip))));
+    }
+  }else
+    printf("res_init() failed.\n");
+  
+}
+#endif