Optimise lokkup_domain()

src/dnsmasq.h

@@ -564,7 +564,7 @@ struct randfd_list {
 
 
 struct server {
-  int flags;
+  u16 flags, domain_len;
   char *domain;
   struct server *next;
   int serial, arrayposn;
@@ -583,23 +583,23 @@ struct server {
 #endif
 };
 
-/* First three fields must match struct server in next three definitions.. */
+/* First four fields must match struct server in next three definitions.. */
 struct serv_addr4 {
-  int flags;
+  u16 flags, domain_len;
   char *domain;
   struct server *next;
   struct in_addr addr;
 };
 
 struct serv_addr6 {
-  int flags;
+  u16 flags, domain_len;
   char *domain;
   struct server *next;
   struct in6_addr addr;
 };
 
 struct serv_local {
-  int flags;
+  u16 flags, domain_len;
   char *domain;
   struct server *next;
 };
@@ -1381,7 +1381,7 @@ void set_option_bool(unsigned int opt);
 void reset_option_bool(unsigned int opt);
 struct hostsfile *expand_filelist(struct hostsfile *list);
 char *parse_server(char *arg, union mysockaddr *addr, 
-		   union mysockaddr *source_addr, char *interface, int *flags);
+		   union mysockaddr *source_addr, char *interface, u16 *flags);
 int option_read_dynfile(char *file, int flags);
 
 /* forward.c */

src/domain-match.c

@@ -79,18 +79,18 @@ void build_server_array(void)
 */
 int lookup_domain(char *qdomain, int flags, int *lowout, int *highout)
 {
-  int rc, nodots, leading_dot = 1;
-  ssize_t qlen, maxlen;
+  int rc, crop_query, nodots, leading_dot = 1;
+  ssize_t qlen;
   int try, high, low = 0;
   int nlow = 0, nhigh = 0;
   char *cp;
 
+  int compares = 0;
+
   /* may be no configured servers. */
   if (daemon->serverarraysz == 0)
     return 0;
   
-  maxlen = strlen(daemon->serverarray[0]->domain);
-  
   /* find query length and presence of '.' */
   for (cp = qdomain, nodots = 1, qlen = 0; *cp; qlen++, cp++)
     if (*cp == '.')
@@ -101,13 +101,8 @@ int lookup_domain(char *qdomain, int flags, int *lowout, int *highout)
   if (qlen == 0 || flags & F_DNSSECOK)
     nodots = 0;
 
-  /* No point trying to match more than the largest server domain */
-  if (qlen > maxlen)
-    {
-      qdomain += qlen - maxlen;
-      qlen = maxlen;
-      leading_dot = 0;
-    }
+  /* account for leading dot */
+  qlen++;
   
   /* Search shorter and shorter RHS substrings for a match */
   while (qlen >= 0)
@@ -115,14 +110,19 @@ int lookup_domain(char *qdomain, int flags, int *lowout, int *highout)
       /* Note that when we chop off a character, all the possible matches
 	 MUST be at a larger index than the nearest failing match with one more
 	 character, since the array is sorted longest to smallest. Hence 
-	 we don't reset low here. */
+	 we don't reset low to zero here, we can go further below and crop the 
+	 search string to the size of the largest remaining server
+	 when this match fails. */
       high = daemon->serverarraysz;
+      crop_query = 1;
       
       /* binary search */
-      do 
+      while (1) 
 	{
 	  try = (low + high)/2;
 
+	  compares++;
+
 	  if ((rc = order(qdomain, leading_dot, qlen, daemon->serverarray[try])) == 0)
 	    break;
 	  
@@ -138,19 +138,14 @@ int lookup_domain(char *qdomain, int flags, int *lowout, int *highout)
 		break;
 	      low = try;
 	    }
-	}
-      while (low != high);
+	};
       
       if (rc == 0)
 	{
 	  /* We've matched a setting which says to use servers without a domain.
-	     Continue the search with empty query (the last character gets stripped
-	     by the loop. */
+	     Continue the search with empty query */
 	  if (daemon->serverarray[try]->flags & SERV_USE_RESOLV)
-	    {
-	      qdomain += qlen - 1;
-	      qlen = 1;
-	    }
+	    crop_query = qlen;
 	  else
 	    {
 	      /* We have a match, but it may only be (say) an IPv6 address, and
@@ -160,27 +155,50 @@ int lookup_domain(char *qdomain, int flags, int *lowout, int *highout)
 		break;
 	    }
 	}
-
-      if (leading_dot)
-	leading_dot = 0;
       else
 	{
-	  qlen--;
-	  qdomain++;
+	  /* try now points to the last domain that sorts before the query, so 
+	     we know that a substring of the query shorter than it is required to match, so
+	     find the largest domain that's shorter than try. Note that just going to
+	     try+1 is not optimal, consider searching bbb in (aaa,ccc,bb). try will point
+	     to aaa, since ccc sorts after bbb, but the first domain that has a chance to 
+	     match is dd. So find the length of the first domain later than try which is
+	     is shorter than it. */
+	  ssize_t len, old = daemon->serverarray[try]->domain_len;
+	  while (++try != daemon->serverarraysz)
+	    {
+	      if (old != (len = daemon->serverarray[try]->domain_len))
+	      {
+		/* crop_query must be at least one always. */
+		if (qlen != len)
+		  crop_query = qlen - len;
+		break;
 	      }
 	    }
+	}
+      
+      qlen -= crop_query;
+      if (leading_dot)
+	{
+	  leading_dot = 0;
+	  crop_query--;
+	}
+      qdomain += crop_query;
+    }
+
+  printf("compares: %d\n", compares);
   
   /* domain has no dots, and we have at least one server configured to handle such,
      These servers always sort to the very end of the array. 
      A configured server eg server=/lan/ will take precdence. */
   if (nodots &&
       (daemon->serverarray[daemon->serverarraysz-1]->flags & SERV_FOR_NODOTS) &&
-      (nlow == nhigh || strlen(daemon->serverarray[nlow]->domain) == 0))
+      (nlow == nhigh || daemon->serverarray[nlow]->domain_len == 0))
     filter_servers(daemon->serverarraysz-1, flags, &nlow, &nhigh);
   
   /* F_DOMAINSRV returns only domain-specific servers, so if we got to a 
      general server, return empty set. */
-  if (nlow != nhigh && (flags & F_DOMAINSRV) && strlen(daemon->serverarray[nlow]->domain) == 0)
+  if (nlow != nhigh && (flags & F_DOMAINSRV) && daemon->serverarray[nlow]->domain_len == 0)
     nlow = nhigh;
   
   if (lowout)
@@ -382,10 +400,7 @@ static int order(char *qdomain, int leading_dot, size_t qlen, struct server *ser
   if (serv->flags & SERV_FOR_NODOTS)
     return -1;
 
-  if (leading_dot)
-    qlen++;
-  
-  dlen = strlen(serv->domain);
+  dlen = serv->domain_len;
   
   if (qlen < dlen)
     return 1;
@@ -401,14 +416,13 @@ static int order(char *qdomain, int leading_dot, size_t qlen, struct server *ser
 
 static int order_servers(struct server *s1, struct server *s2)
 {
-   size_t dlen = strlen(s1->domain);
-
   /* need full comparison of dotless servers in 
      order_qsort() and filter_servers() */
+
   if (s1->flags & SERV_FOR_NODOTS)
      return (s2->flags & SERV_FOR_NODOTS) ? 0 : 1;
    
-   return order(s1->domain, 0, dlen, s2);
+   return order(s1->domain, 0, s1->domain_len, s2);
 }
   
 static int order_qsort(const void *a, const void *b)

src/forward.c

@@ -153,9 +153,8 @@ static int domain_no_rebind(char *domain)
   struct server *serv;
   int dlen = (int)strlen(domain);
   
-  /* flags is misused to hold length of domain. */
   for (serv = daemon->no_rebind; serv; serv = serv->next)
-    if (dlen >= serv->flags && strcmp(serv->domain, &domain[dlen - serv->flags]) == 0)
+    if (dlen >= serv->domain_len && strcmp(serv->domain, &domain[dlen - serv->flags]) == 0)
       return 1;
 
   return 0;

src/network.c

@@ -1617,7 +1617,7 @@ void add_update_server(int flags,
 
       serv->flags = flags;
       serv->domain = domain_str;
-
+      serv->domain_len = strlen(domain_str);
 
       if (!(flags & SERV_IS_LOCAL))
 	{

src/option.c

@@ -812,7 +812,7 @@ static char *parse_mysockaddr(char *arg, union mysockaddr *addr)
   return NULL;
 }
 
-char *parse_server(char *arg, union mysockaddr *addr, union mysockaddr *source_addr, char *interface, int *flags)
+char *parse_server(char *arg, union mysockaddr *addr, union mysockaddr *source_addr, char *interface, u16 *flags)
 {
   int source_port = 0, serv_port = NAMESERVER_PORT;
   char *portno, *source;
@@ -2617,7 +2617,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	  comma = split_chr(arg, '/');
 	  new = opt_malloc(sizeof(struct serv_local));
 	  new->domain = opt_string_alloc(arg);
-	  new->flags = strlen(arg);
+	  new->domain_len = strlen(arg);
 	  new->next = daemon->no_rebind;
 	  daemon->no_rebind = new;
 	  arg = comma;
@@ -2634,7 +2634,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	size_t size;
 	char *lastdomain = NULL, *domain = "";
 	char *alloc_domain;
-	int flags = 0;
+	u16 flags = 0;
 	char *err;
 	struct in_addr addr4;
 	struct in6_addr addr6;
@@ -2730,6 +2730,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	  }
 	
 	new->domain = alloc_domain;
+	new->domain_len = strlen(alloc_domain);
 	
 	/* server=//1.2.3.4 is special. */
 	if (strlen(domain) == 0 && lastdomain)
@@ -2751,6 +2752,8 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	       new = opt_malloc(size);
 	       memcpy(new, last, size);
 	       new->domain = alloc_domain;
+	       new->domain_len = strlen(alloc_domain);
+
 	       if (flags & (SERV_USE_RESOLV | SERV_LITERAL_ADDRESS))
 		 {
 		   new->next = daemon->local_domains;