Add --ignore-address option.

src/dnsmasq.h

@@ -930,7 +930,7 @@ extern struct daemon {
   char *runfile; 
   char *lease_change_command;
   struct iname *if_names, *if_addrs, *if_except, *dhcp_except, *auth_peers, *tftp_interfaces;
-  struct bogus_addr *bogus_addr;
+  struct bogus_addr *bogus_addr, *ignore_addr;
   struct server *servers;
   struct ipsets *ipsets;
   int log_fac; /* log facility */
@@ -1093,6 +1093,7 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
 		      time_t now, int *ad_reqd, int *do_bit);
 int check_for_bogus_wildcard(struct dns_header *header, size_t qlen, char *name, 
 			     struct bogus_addr *addr, time_t now);
+int check_for_ignored_address(struct dns_header *header, size_t qlen, struct bogus_addr *baddr);
 unsigned char *find_pseudoheader(struct dns_header *header, size_t plen,
 				 size_t *len, unsigned char **p, int *is_sign);
 int check_for_local_domain(char *name, time_t now);

src/forward.c

@@ -724,6 +724,10 @@ void reply_query(int fd, int family, time_t now)
   if (!(forward = lookup_frec(ntohs(header->id), hash)))
     return;
   
+  if (daemon->ignore_addr && RCODE(header) == NOERROR &&
+      check_for_ignored_address(header, n, daemon->ignore_addr))
+    return;
+
   if ((RCODE(header) == SERVFAIL || RCODE(header) == REFUSED) &&
       !option_bool(OPT_ORDER) &&
       forward->forwardall == 0)

src/option.c

@@ -147,6 +147,7 @@ struct myoption {
 #define LOPT_LOCAL_SERVICE 335
 #define LOPT_DNSSEC_TIME   336
 #define LOPT_LOOP_DETECT   337
+#define LOPT_IGNORE_ADDR   338
 
 #ifdef HAVE_GETOPT_LONG
 static const struct option opts[] =  
@@ -181,6 +182,7 @@ static const struct myoption opts[] =
     { "local-service", 0, 0, LOPT_LOCAL_SERVICE },
     { "bogus-priv", 0, 0, 'b' },
     { "bogus-nxdomain", 1, 0, 'B' },
+    { "ignore-address", 1, 0, LOPT_IGNORE_ADDR },
     { "selfmx", 0, 0, 'e' },
     { "filterwin2k", 0, 0, 'f' },
     { "pid-file", 2, 0, 'x' },
@@ -457,6 +459,7 @@ static struct {
   { LOPT_QUIET_RA, OPT_QUIET_RA, NULL, gettext_noop("Do not log RA."), NULL },
   { LOPT_LOCAL_SERVICE, OPT_LOCAL_SERVICE, NULL, gettext_noop("Accept queries only from directly-connected networks"), NULL },
   { LOPT_LOOP_DETECT, OPT_LOOP_DETECT, NULL, gettext_noop("Detect and remove DNS forwarding loops"), NULL },
+  { LOPT_IGNORE_ADDR, ARG_DUP, "<ipaddr>", gettext_noop("Ignore DNS responses containing ipaddr."), NULL }, 
   { 0, 0, NULL, NULL, NULL }
 }; 
 
@@ -2119,14 +2122,23 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
       break;
       
     case 'B':  /* --bogus-nxdomain */
-      {
+    case LOPT_IGNORE_ADDR: /* --ignore-address */
+     {
 	struct in_addr addr;
 	unhide_metas(arg);
 	if (arg && (inet_pton(AF_INET, arg, &addr) > 0))
 	  {
 	    struct bogus_addr *baddr = opt_malloc(sizeof(struct bogus_addr));
-	    baddr->next = daemon->bogus_addr;
-	    daemon->bogus_addr = baddr;
+	    if (option == 'B')
+	      {
+		baddr->next = daemon->bogus_addr;
+		daemon->bogus_addr = baddr;
+	      }
+	    else
+	      {
+		baddr->next = daemon->ignore_addr;
+		daemon->ignore_addr = baddr;
+	      }
 	    baddr->addr = addr;
 	  }
 	else

src/rfc1035.c

@@ -1328,6 +1328,43 @@ int check_for_bogus_wildcard(struct dns_header *header, size_t qlen, char *name,
   return 0;
 }
 
+int check_for_ignored_address(struct dns_header *header, size_t qlen, struct bogus_addr *baddr)
+{
+  unsigned char *p;
+  int i, qtype, qclass, rdlen;
+  struct bogus_addr *baddrp;
+
+  /* skip over questions */
+  if (!(p = skip_questions(header, qlen)))
+    return 0; /* bad packet */
+
+  for (i = ntohs(header->ancount); i != 0; i--)
+    {
+      if (!(p = skip_name(p, header, qlen, 10)))
+	return 0; /* bad packet */
+      
+      GETSHORT(qtype, p); 
+      GETSHORT(qclass, p);
+      p += 4; /* TTL */
+      GETSHORT(rdlen, p);
+      
+      if (qclass == C_IN && qtype == T_A)
+	{
+	  if (!CHECK_LEN(header, p, qlen, INADDRSZ))
+	    return 0;
+	  
+	  for (baddrp = baddr; baddrp; baddrp = baddrp->next)
+	    if (memcmp(&baddrp->addr, p, INADDRSZ) == 0)
+	      return 1;
+	}
+      
+      if (!ADD_RDLEN(header, p, qlen, rdlen))
+	return 0;
+    }
+  
+  return 0;
+}
+
 int add_resource_record(struct dns_header *header, char *limit, int *truncp, int nameoffset, unsigned char **pp, 
 			unsigned long ttl, int *offset, unsigned short type, unsigned short class, char *format, ...)
 {