[PATCH 1/2] GIT: Try all addresses for given remote name

Hello.

Try all addresses for given remote name until it succeeds.
Also supports IPv6.

Signed-of-by: Hideaki YOSHIFUJI [off-list ref]

diff --git a/connect.c b/connect.c
--- a/connect.c
+++ b/connect.c

@@ -96,42 +96,57 @@ static enum protocol get_protocol(const 
 	die("I don't handle protocol '%s'", name);
 }
 
-static void lookup_host(const char *host, struct sockaddr *in)
-{
-	struct addrinfo *res;
-	int ret;
-
-	ret = getaddrinfo(host, NULL, NULL, &res);
-	if (ret)
-		die("Unable to look up %s (%s)", host, gai_strerror(ret));
-	*in = *res->ai_addr;
-	freeaddrinfo(res);
-}
+#define STR_(s)	# s
+#define STR(s)	STR_(s)
 
 static int git_tcp_connect(int fd[2], const char *prog, char *host, char *path)
 {
-	struct sockaddr addr;
-	int port = DEFAULT_GIT_PORT, sockfd;
-	char *colon;
-
-	colon = strchr(host, ':');
-	if (colon) {
-		char *end;
-		unsigned long n = strtoul(colon+1, &end, 0);
-		if (colon[1] && !*end) {
-			*colon = 0;
-			port = n;
+	int sockfd = -1;
+	char *colon, *end;
+	char *port = STR(DEFAULT_GIT_PORT);
+	struct addrinfo hints, *ai0, *ai;
+	int gai;
+
+	if (host[0] == '[') {
+		end = strchr(host + 1, ']');
+		if (end) {
+			*end = 0;
+			end++;
+			host++;
+		} else
+			end = host;
+	} else
+		end = host;
+	colon = strchr(end, ':');
+
+	if (colon)
+		port = colon + 1;
+
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_socktype = SOCK_STREAM;
+	hints.ai_protocol = IPPROTO_TCP;
+
+	gai = getaddrinfo(host, port, &hints, &ai);
+	if (gai)
+		die("Unable to look up %s (%s)", host, gai_strerror(gai));
+
+	for (ai0 = ai; ai; ai = ai->ai_next) {
+		sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+		if (sockfd < 0)
+			continue;
+		if (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
+			close(sockfd);
+			sockfd = -1;
+			continue;
 		}
+		break;
 	}
 
-	lookup_host(host, &addr);
-	((struct sockaddr_in *)&addr)->sin_port = htons(port);
+	freeaddrinfo(ai0);
 
-	sockfd = socket(PF_INET, SOCK_STREAM, IPPROTO_IP);
 	if (sockfd < 0)
 		die("unable to create socket (%s)", strerror(errno));
-	if (connect(sockfd, (void *)&addr, sizeof(addr)) < 0)
-		die("unable to connect (%s)", strerror(errno));
+
 	fd[0] = sockfd;
 	fd[1] = sockfd;
 	packet_write(sockfd, "%s %s\n", prog, path);

-- 
YOSHIFUJI Hideaki @ USAGI Project  <yoshfuji@linux-ipv6.org>
GPG-FP  : 9022 65EB 1ECF 3AD1 0BDF  80D8 4807 F894 E062 0EEA

Dear diary, on Thu, Jul 21, 2005 at 03:10:36PM CEST, I got a letter
where "YOSHIFUJI Hideaki / ?$B5HF#1QL@" [off-list ref] told me that...

Hello.

Hello,

Uh-huh? Why two macros? Well, why any macros at all?

 static int git_tcp_connect(int fd[2], const char *prog, char *host, char *path)
 {
-	struct sockaddr addr;
-	int port = DEFAULT_GIT_PORT, sockfd;
-	char *colon;
-
-	colon = strchr(host, ':');
-	if (colon) {
-		char *end;
-		unsigned long n = strtoul(colon+1, &end, 0);
-		if (colon[1] && !*end) {
-			*colon = 0;
-			port = n;
+	int sockfd = -1;
+	char *colon, *end;
+	char *port = STR(DEFAULT_GIT_PORT);
+	struct addrinfo hints, *ai0, *ai;
+	int gai;
+
+	if (host[0] == '[') {
+		end = strchr(host + 1, ']');
+		if (end) {
+			*end = 0;
+			end++;
+			host++;
+		} else
+			end = host;
+	} else
+		end = host;
+	colon = strchr(end, ':');
+
+	if (colon)
+		port = colon + 1;
+
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_socktype = SOCK_STREAM;
+	hints.ai_protocol = IPPROTO_TCP;
+
+	gai = getaddrinfo(host, port, &hints, &ai);
+	if (gai)
+		die("Unable to look up %s (%s)", host, gai_strerror(gai));
+
+	for (ai0 = ai; ai; ai = ai->ai_next) {
+		sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+		if (sockfd < 0)
+			continue;
+		if (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
+			close(sockfd);
+			sockfd = -1;
+			continue;
 		}
+		break;
 	}
 
-	lookup_host(host, &addr);
-	((struct sockaddr_in *)&addr)->sin_port = htons(port);
+	freeaddrinfo(ai0);
 
-	sockfd = socket(PF_INET, SOCK_STREAM, IPPROTO_IP);
 	if (sockfd < 0)
 		die("unable to create socket (%s)", strerror(errno));
-	if (connect(sockfd, (void *)&addr, sizeof(addr)) < 0)
-		die("unable to connect (%s)", strerror(errno));
+
 	fd[0] = sockfd;
 	fd[1] = sockfd;
 	packet_write(sockfd, "%s %s\n", prog, path);

You are saying that you were unable to create socket while you just were
unable to connect.  Not any biggie, but it saves the user the trouble of
one strace after being confused by an error message. :-)

-- 
				Petr "Pasky" Baudis
Stuff: http://pasky.or.cz/
If you want the holes in your knowledge showing up try teaching
someone.  -- Alan Cox

In article [off-list ref] (at Fri, 22 Jul 2005 23:09:13 +0200), Petr Baudis [off-list ref] says:

quoted

-}
+#define STR_(s)	# s
+#define STR(s)	STR_(s)

Uh-huh? Why two macros? Well, why any macros at all?

:

quoted

+	char *colon, *end;
+	char *port = STR(DEFAULT_GIT_PORT);
+	struct addrinfo hints, *ai0, *ai;

The macro is used here.
This is trick.

After preprocess,

/* --- cut here --- */
#define TEST 12345
#define STR_(s) # s
#define STR(s) STR_(s)

test(STR(TEST));
test(STR_(TEST));
test(# TEST);
/* --- cut here --- */

becomes

test("12345");
test("TEST");
test(# 12345);

quoted

 	if (sockfd < 0)
 		die("unable to create socket (%s)", strerror(errno));
-	if (connect(sockfd, (void *)&addr, sizeof(addr)) < 0)
-		die("unable to connect (%s)", strerror(errno));

:

You are saying that you were unable to create socket while you just were
unable to connect.  Not any biggie, but it saves the user the trouble of
one strace after being confused by an error message. :-)

In fact, I don't think it is really worng, because it says that
it could not create (connected) socket or endpoint of connection.

Anyway, I agree that it would be confusing.
Better ideas / wordings?

--yoshfuji

Dear diary, on Fri, Jul 22, 2005 at 11:26:29PM CEST, I got a letter
where "YOSHIFUJI Hideaki / ?$B5HF#1QL@" [off-list ref] told me that...

In article [off-list ref] (at Fri, 22 Jul 2005 23:09:13 +0200), Petr Baudis [off-list ref] says:

quoted

quoted

-}
+#define STR_(s)	# s
+#define STR(s)	STR_(s)

Uh-huh? Why two macros? Well, why any macros at all?

:

quoted

quoted

+	char *colon, *end;
+	char *port = STR(DEFAULT_GIT_PORT);
+	struct addrinfo hints, *ai0, *ai;

The macro is used here.
This is trick.

After preprocess,

/* --- cut here --- */
#define TEST 12345
#define STR_(s) # s
#define STR(s) STR_(s)

test(STR(TEST));
test(STR_(TEST));
test(# TEST);
/* --- cut here --- */

becomes

test("12345");
test("TEST");
test(# 12345);

I see, I didn't know about this. Well, I didn't actually use the #
stringificator many times. Perhaps a short comment would be due.

quoted

quoted

 	if (sockfd < 0)
 		die("unable to create socket (%s)", strerror(errno));
-	if (connect(sockfd, (void *)&addr, sizeof(addr)) < 0)
-		die("unable to connect (%s)", strerror(errno));

:

quoted

You are saying that you were unable to create socket while you just were
unable to connect.  Not any biggie, but it saves the user the trouble of
one strace after being confused by an error message. :-)

In fact, I don't think it is really worng, because it says that
it could not create (connected) socket or endpoint of connection.

It uses only two words ("create socket") from that, though. ;-)

Anyway, I agree that it would be confusing.
Better ideas / wordings?

	if (connect() < 0) sockfd = -2;
	...
	if (sockfd == -1) die("unable to create socket");
	else die("unable to connect")

or I'd prefer the second error message "unable to connect", which is
perhaps more descriptive regarding what effectively happened.

BTW, could the close() on the socket ever fail (read as "modify errno")
here?

-- 
				Petr "Pasky" Baudis
Stuff: http://pasky.or.cz/
If you want the holes in your knowledge showing up try teaching
someone.  -- Alan Cox

On Fri, Jul 22, 2005 at 05:26:29PM -0400, YOSHIFUJI Hideaki / ?$B5HF#1QL@ wrote:

In article [off-list ref] (at Fri, 22 Jul 2005 23:09:13 +0200), Petr Baudis [off-list ref] says:

quoted

quoted

-}
+#define STR_(s)	# s
+#define STR(s)	STR_(s)

Uh-huh? Why two macros? Well, why any macros at all?

:

quoted

quoted

+	char *colon, *end;
+	char *port = STR(DEFAULT_GIT_PORT);
+	struct addrinfo hints, *ai0, *ai;

The macro is used here.

You could copy the include/linux/stingify.h file from the kernel also.
That makes it available for other users also.

	Sam