[svn] Don't reuse IP addresses proven to be faulty, unless only such ones remain.

Published in <sxs8zcsfemf.fsf@florida.arsdigita.de>.

src/ChangeLog

@@ -1,3 +1,12 @@
+2001-11-27  Hrvoje Niksic  <hniksic@arsdigita.com>
+
+	* connect.c (connect_to_many): Use address_list_set_faulty to
+	prevent the faulty address from being reused.
+
+	* host.c (address_list_set_faulty): New function.
+	(address_list_get_bounds): New function, instead of
+	address_list_count.
+
 2001-11-27  Hrvoje Niksic  <hniksic@arsdigita.com>
 
 	* url.c (convert_links): Don't translate %d-%d.

src/connect.c

@@ -146,9 +146,10 @@ connect_to_one (const unsigned char *addr, unsigned short port, int silent)
 int
 connect_to_many (struct address_list *al, unsigned short port, int silent)
 {
-  int i;
+  int i, start, end;
 
-  for (i = 0; i < address_list_count (al); i++)
+  address_list_get_bounds (al, &start, &end);
+  for (i = start; i < end; i++)
     {
       unsigned char addr[4];
       int sock;
@@ -156,10 +157,10 @@ connect_to_many (struct address_list *al, unsigned short port, int silent)
 
       sock = connect_to_one (addr, port, silent);
       if (sock >= 0)
+	/* Success. */
 	return sock;
 
-      /* Perhaps we should have a way of removing the failing entry
-	 from the address list?  */
+      address_list_set_faulty (al, i);
 
       /* The attempt to connect has failed.  Continue with the loop
 	 and try next address. */

src/host.c

@@ -72,18 +72,21 @@ struct address_list {
   int count;			/* number of adrresses */
   unsigned char *buffer;	/* buffer which holds all of them. */
 
+  int faulty;			/* number of addresses known not to
+				   work. */
   int refcount;			/* so we know whether to free it or
 				   not. */
 };
 
 #define ADDR_LOCATION(al, index) ((al)->buffer + index * IP4_ADDRESS_LENGTH)
 
-/* Return the number of addresses in the list. */
+/* Get the bounds of the address list.  */
 
-int
-address_list_count (struct address_list *al)
+void
+address_list_get_bounds (struct address_list *al, int *start, int *end)
 {
-  return al->count;
+  *start = al->faulty;
+  *end   = al->count;
 }
 
 /* Copy address number INDEX to IP_STORE.  */
@@ -92,6 +95,7 @@ void
 address_list_copy_one (struct address_list *al, int index,
 		       unsigned char *ip_store)
 {
+  assert (index >= al->faulty && index < al->count);
   memcpy (ip_store, ADDR_LOCATION (al, index), IP4_ADDRESS_LENGTH);
 }
 
@@ -108,6 +112,21 @@ address_list_match_all (struct address_list *al1, struct address_list *al2)
 		      al1->count * IP4_ADDRESS_LENGTH);
 }
 
+/* Mark the INDEXth element of AL as faulty, so that the next time
+   this address list is used, the faulty element will be skipped.  */
+
+void
+address_list_set_faulty (struct address_list *al, int index)
+{
+  ++al->faulty;
+  if (al->faulty >= al->count)
+    /* All addresses have been proven faulty.  Since there's not much
+       sense in returning the user an empty address list the next
+       time, we'll rather make them all clean, so that they can be
+       retried anew.  */
+    al->faulty = 0;
+}
+
 /* Create an address_list out of a NULL-terminated list of addresses,
    as returned by gethostbyname.  */
 

src/host.h

@@ -27,12 +27,13 @@ struct address_list;
 struct address_list *lookup_host PARAMS ((const char *, int));
 char *herrmsg PARAMS ((int));
 
-int address_list_count PARAMS ((struct address_list *));
+void address_list_get_bounds PARAMS ((struct address_list *, int *, int *));
 void address_list_copy_one PARAMS ((struct address_list *, int,
 				    unsigned char *));
-void address_list_release PARAMS ((struct address_list *));
 int address_list_match_all PARAMS ((struct address_list *,
 				    struct address_list *));
+void address_list_set_faulty PARAMS ((struct address_list *, int));
+void address_list_release PARAMS ((struct address_list *));
 
 /* This was originally going to be a macro, but then every caller
    would have to #include the netinet stuff.  */