Support addresses with ':' in git-daemon

If host address could have ':' in it (e.g. numeric IPv6 address), then
host and port could not be uniquely parsed. Fix this by parsing the
"["<host>"]":<port> and "["<host>"]" notations. Currently the built-in
git:// client would send <host>:<port> or <host> for such thing, but
it doesn't matter as due to bugs, resolving address fails if <host>
contains ':'.
Signed-off-by: NIlari Liusvaara <ilari.liusvaara@elisanet.fi>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

daemon.c

@@ -445,6 +445,33 @@ static char *xstrdup_tolower(const char *str)
 	return dup;
 }
 
+static void parse_host_and_port(char *hostport, char **host,
+	char **port)
+{
+	if (*hostport == '[') {
+		char *end;
+
+		end = strchr(hostport, ']');
+		if (!end)
+			die("Invalid reqeuest ('[' without ']')");
+		*end = '\0';
+		*host = hostport + 1;
+		if (!end[1])
+			*port = NULL;
+		else if (end[1] == ':')
+			*port = end + 2;
+		else
+			die("Garbage after end of host part");
+	} else {
+		*host = hostport;
+		*port = strrchr(hostport, ':');
+		if (*port) {
+			*port = '\0';
+			++*port;
+		}
+	}
+}
+
 /*
  * Read the host as supplied by the client connection.
  */
@@ -461,11 +488,10 @@ static void parse_host_arg(char *extra_args, int buflen)
 			vallen = strlen(val) + 1;
 			if (*val) {
 				/* Split <host>:<port> at colon. */
-				char *host = val;
-				char *port = strrchr(host, ':');
+				char *host;
+				char *port;
+				parse_host_and_port(val, &host, &port);
 				if (port) {
-					*port = 0;
-					port++;
 					free(tcp_port);
 					tcp_port = xstrdup(port);
 				}