daemon: consider only address in kill_some_child()

kill_some_child() compares the entire sockaddr_storage
structure (with the pad-bits zeroed out) when trying to
find out if connections originate from the same host.
However, sockaddr_storage contains the port-number for
the connection (which varies between connections), so
the comparison always fails.

Change the code so we only consider the host-address,
by introducing the addrcmp()-function that inspects
the address family and compare as appropriate.

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

daemon.c

@@ -562,6 +562,24 @@ static int execute(struct sockaddr *addr)
 	return -1;
 }
 
+static int addrcmp(const struct sockaddr_storage *s1,
+    const struct sockaddr_storage *s2)
+{
+	if (s1->ss_family != s2->ss_family)
+		return s1->ss_family - s2->ss_family;
+	if (s1->ss_family == AF_INET)
+		return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
+		    &((struct sockaddr_in *)s2)->sin_addr,
+		    sizeof(struct in_addr));
+#ifndef NO_IPV6
+	if (s1->ss_family == AF_INET6)
+		return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
+		    &((struct sockaddr_in6 *)s2)->sin6_addr,
+		    sizeof(struct in6_addr));
+#endif
+	return 0;
+}
+
 static int max_connections = 32;
 
 static unsigned int live_children;
@@ -576,17 +594,12 @@ static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 {
 	struct child *newborn, **cradle;
 
-	/*
-	 * This must be xcalloc() -- we'll compare the whole sockaddr_storage
-	 * but individual address may be shorter.
-	 */
 	newborn = xcalloc(1, sizeof(*newborn));
 	live_children++;
 	newborn->pid = pid;
 	memcpy(&newborn->address, addr, addrlen);
 	for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
-		if (!memcmp(&(*cradle)->address, &newborn->address,
-			    sizeof(newborn->address)))
+		if (!addrcmp(&(*cradle)->address, &newborn->address))
 			break;
 	newborn->next = *cradle;
 	*cradle = newborn;
@@ -619,8 +632,7 @@ static void kill_some_child(void)
 		return;
 
 	for (; (next = blanket->next); blanket = next)
-		if (!memcmp(&blanket->address, &next->address,
-			    sizeof(next->address))) {
+		if (!addrcmp(&blanket->address, &next->address)) {
 			kill(blanket->pid, SIGTERM);
 			break;
 		}