lib9/dial: add support for IPv6

The function p9dialparse() returns the host as a sockaddr_storage
structure instead of a u32int, to be able to handle both IPv4
and IPv6 addresses. Because the sockaddr_storage structure also
handle port numbers and Unix path names, there is no longer
need to set them in the calling functions. However, these values
are still returned for convenience.

The sockaddr_in and sockaddr_un structures have been replaced
by sockaddr_storage to handle Unix, IPv4 and IPv6 sockets.

Names and addresses are resolved using either gethostbyname()
or getaddrinfo() functions.

The getaddrinfo() function is documented in RFC2553 and standardized
since POSIX.1-2001. It supports both IPv4 and IPv6 addresses.
The gethostbyname() function is deprecated since POSIX.1-2008.
However, some libc implementations don't handle getaddrinfo()
properly, thus we preferred to try gethostbyname() first.

I've tried to preserve most of the old code logic to prevent
from surprising or unwanted behavior.

R=rsc
http://codereview.appspot.com/6255068

3 files changed, 86 insertions, 100 deletions

diff --git a/src/lib9/_p9dialparse.c b/src/lib9/_p9dialparse.c
index 0c84ecdb..d8e91003 100644
--- a/src/lib9/_p9dialparse.c
+++ b/src/lib9/_p9dialparse.c
@@ -31,58 +31,35 @@ static struct {
 };
 
 static int
-parseip(char *host, u32int *pip)
+setport(struct sockaddr_storage *ss, int port)
 {
-	uchar addr[4];
-	int x, i;
-	char *p;
-
-	p = host;
-	for(i=0; i<4 && *p; i++){
-		x = strtoul(p, &p, 0);
-		if(x < 0 || x >= 256)
-			return -1;
-		if(*p != '.' && *p != 0)
-			return -1;
-		if(*p == '.')
-			p++;
-		addr[i] = x;
-	}
-
-	switch(CLASS(addr)){
-	case 0:
-	case 1:
-		if(i == 3){
-			addr[3] = addr[2];
-			addr[2] = addr[1];
-			addr[1] = 0;
-		}else if(i == 2){
-			addr[3] = addr[1];
-			addr[2] = 0;
-			addr[1] = 0;
-		}else if(i != 4)
-			return -1;
+	switch(ss->ss_family){
+	case AF_INET:
+		((struct sockaddr_in*)ss)->sin_port = htons(port);
 		break;
-	case 2:
-		if(i == 3){
-			addr[3] = addr[2];
-			addr[2] = 0;
-		}else if(i != 4)
-			return -1;
+	case AF_INET6:
+		((struct sockaddr_in6*)ss)->sin6_port = htons(port);
 		break;
+	default:
+		errstr("unknown protocol family %d", ss->ss_family);
+		return -1;
 	}
-	memmove(pip, addr, 4);
 	return 0;
 }
 
 int
-p9dialparse(char *addr, char **pnet, char **punix, u32int *phost, int *pport)
+p9dialparse(char *addr, char **pnet, char **punix, void *phost, int *pport)
 {
 	char *net, *host, *port, *e;
 	int i;
 	struct servent *se;
 	struct hostent *he;
-	struct sockaddr_un *sockun;
+	struct sockaddr_storage *ss;
+	struct addrinfo *result;
+
+	ss = phost;
+
+	memset(ss, 0, sizeof(ss));
 
 	*punix = nil;
 	net = addr;
@@ -94,13 +71,14 @@ p9dialparse(char *addr, char **pnet, char **punix, u32int *phost, int *pport)
 	if((port = strchr(host, '!')) == nil){
 		if(strcmp(net, "unix")==0 || strcmp(net, "net")==0){
 		Unix:
-			if(strlen(host)+1 > sizeof sockun->sun_path){
+			if(strlen(host)+1 > sizeof ((struct sockaddr_un*)&ss)->sun_path){
 				werrstr("unix socket name too long");
 				return -1;
 			}
 			*punix = host;
 			*pnet = "unix";
-			*phost = 0;
+			ss->ss_family = AF_UNIX;
+			strcpy(((struct sockaddr_un*)ss)->sun_path, host);
 			*pport = 0;
 			return 0;
 		}
@@ -127,13 +105,36 @@ p9dialparse(char *addr, char **pnet, char **punix, u32int *phost, int *pport)
 	}
 
 	/* translate host */
-	if(strcmp(host, "*") == 0)
-		*phost = 0;
-	else if(parseip(host, phost) == 0)
-		{}
-	else if((he = gethostbyname(host)) != nil)
-		*phost = *(u32int*)(he->h_addr);
-	else{
+	if(strcmp(host, "*") == 0){
+		ss->ss_family = AF_INET6;
+		((struct sockaddr_in6*)ss)->sin6_addr = in6addr_any;
+	}else if((he = gethostbyname(host)) != nil){
+		ss->ss_family = he->h_addrtype;
+		switch(ss->ss_family){
+		case AF_INET:
+			((struct sockaddr_in*)ss)->sin_addr = *(struct in_addr*) *(he->h_addr_list);
+			break;
+		case AF_INET6:
+			((struct sockaddr_in6*)ss)->sin6_addr = *(struct in6_addr*) *(he->h_addr_list);
+			break;
+		default:
+			errstr("unknown protocol family %d", ss->ss_family);
+			return -1;
+		}
+	}else if(getaddrinfo(host, NULL, NULL, &result) == 0) {
+		ss->ss_family = result->ai_family;
+		switch (ss->ss_family) {
+		case AF_INET:
+			memcpy((struct sockaddr_in*)ss, result->ai_addr, result->ai_addrlen);
+			break;
+		case AF_INET6:
+			memcpy((struct sockaddr_in6*)ss, result->ai_addr, result->ai_addrlen);
+			break;
+		default:
+			errstr("unknown protocol family %d", ss->ss_family);
+			return -1;
+		}
+	}else{
 		werrstr("unknown host %s", host);
 		return -1;
 	}
@@ -144,7 +145,7 @@ p9dialparse(char *addr, char **pnet, char **punix, u32int *phost, int *pport)
 			if((se = getservbyname(port, nets[i])) != nil){
 				*pnet = nets[i];
 				*pport = ntohs(se->s_port);
-				return 0;
+				return setport(ss, *pport);
 			}
 		}
 	}
@@ -154,7 +155,7 @@ p9dialparse(char *addr, char **pnet, char **punix, u32int *phost, int *pport)
 		if(strcmp(porttbl[i].service, port) == 0){
 			*pnet = porttbl[i].net;
 			*pport = porttbl[i].port;
-			return 0;
+			return setport(ss, *pport);
 		}
 	}
 
@@ -172,12 +173,12 @@ p9dialparse(char *addr, char **pnet, char **punix, u32int *phost, int *pport)
 	i = strtol(port, &e, 0);
 	if(*e == 0){
 		*pport = i;
-		return 0;
+		return setport(ss, *pport);
 	}
 
 	if((se = getservbyname(port, net)) != nil){
 		*pport = ntohs(se->s_port);
-		return 0;
+		return setport(ss, *pport);
 	}
 	werrstr("unknown service %s!*!%s", net, port);
 	return -1;
diff --git a/src/lib9/announce.c b/src/lib9/announce.c
index ecdd897a..6e5357c5 100644
--- a/src/lib9/announce.c
+++ b/src/lib9/announce.c
@@ -39,18 +39,16 @@ p9announce(char *addr, char *dir)
 	int proto;
 	char *buf, *unix;
 	char *net;
-	u32int host;
 	int port, s;
 	int n;
 	socklen_t sn;
-	struct sockaddr_in sa;
-	struct sockaddr_un sun;
+	struct sockaddr_storage ss;
 
 	buf = strdup(addr);
 	if(buf == nil)
 		return -1;
 
-	if(p9dialparse(buf, &net, &unix, &host, &port) < 0){
+	if(p9dialparse(buf, &net, &unix, &ss, &port) < 0){
 		free(buf);
 		return -1;
 	}
@@ -67,11 +65,7 @@ p9announce(char *addr, char *dir)
 	}
 	free(buf);
 
-	memset(&sa, 0, sizeof sa);
-	memmove(&sa.sin_addr, &host, 4);
-	sa.sin_family = AF_INET;
-	sa.sin_port = htons(port);
-	if((s = socket(AF_INET, proto, 0)) < 0)
+	if((s = socket(ss.ss_family, proto, 0)) < 0)
 		return -1;
 	sn = sizeof n;
 	if(port && getsockopt(s, SOL_SOCKET, SO_TYPE, (void*)&n, &sn) >= 0
@@ -79,7 +73,7 @@ p9announce(char *addr, char *dir)
 		n = 1;
 		setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char*)&n, sizeof n);
 	}
-	if(bind(s, (struct sockaddr*)&sa, sizeof sa) < 0){
+	if(bind(s, (struct sockaddr*)&ss, sizeof ss) < 0){
 		close(s);
 		return -1;
 	}
@@ -90,22 +84,18 @@ p9announce(char *addr, char *dir)
 	return s;
 
 Unix:
-	memset(&sun, 0, sizeof sun);
-	sun.sun_family = AF_UNIX;
-	strcpy(sun.sun_path, unix);
-	if((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
+	if((s = socket(ss.ss_family, SOCK_STREAM, 0)) < 0)
 		return -1;
-	sn = sizeof sun;
-	if(bind(s, (struct sockaddr*)&sun, sizeof sun) < 0){
+	if(bind(s, (struct sockaddr*)&ss, sizeof (struct sockaddr_un)) < 0){
 		if(errno == EADDRINUSE
-		&& connect(s, (struct sockaddr*)&sun, sizeof sun) < 0
+		&& connect(s, (struct sockaddr*)&ss, sizeof (struct sockaddr_un)) < 0
 		&& errno == ECONNREFUSED){
 			/* dead socket, so remove it */
 			remove(unix);
 			close(s);
-			if((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
+			if((s = socket(ss.ss_family, SOCK_STREAM, 0)) < 0)
 				return -1;
-			if(bind(s, (struct sockaddr*)&sun, sizeof sun) >= 0)
+			if(bind(s, (struct sockaddr*)&ss, sizeof (struct sockaddr_un)) >= 0)
 				goto Success;
 		}
 		close(s);
diff --git a/src/lib9/dial.c b/src/lib9/dial.c
index 7c7f7480..730b60e3 100644
--- a/src/lib9/dial.c
+++ b/src/lib9/dial.c
@@ -19,18 +19,29 @@
 #undef unix
 #define unix xunix
 
+static int
+isany(struct sockaddr_storage *ss)
+{
+	switch(ss->ss_family){
+	case AF_INET:
+		return (((struct sockaddr_in*)ss)->sin_addr.s_addr == INADDR_ANY);
+	case AF_INET6:
+		return (memcmp(((struct sockaddr_in6*)ss)->sin6_addr.s6_addr,
+			in6addr_any.s6_addr, sizeof (struct in6_addr)) == 0);
+	}
+	return 0;
+}
+
 int
 p9dial(char *addr, char *local, char *dummy2, int *dummy3)
 {
 	char *buf;
 	char *net, *unix;
-	u32int host;
 	int port;
 	int proto;
 	socklen_t sn;
 	int n;
-	struct sockaddr_in sa, sal;	
-	struct sockaddr_un su;
+	struct sockaddr_storage ss, ssl;
 	int s;
 
 	if(dummy2 || dummy3){
@@ -42,11 +53,11 @@ p9dial(char *addr, char *local, char *dummy2, int *dummy3)
 	if(buf == nil)
 		return -1;
 
-	if(p9dialparse(buf, &net, &unix, &host, &port) < 0){
+	if(p9dialparse(buf, &net, &unix, &ss, &port) < 0){
 		free(buf);
 		return -1;
 	}
-	if(strcmp(net, "unix") != 0 && host == 0){
+	if(strcmp(net, "unix") != 0 && isany(&ss)){
 		werrstr("invalid dial address 0.0.0.0 (aka *)");
 		free(buf);
 		return -1;
@@ -65,7 +76,7 @@ p9dial(char *addr, char *local, char *dummy2, int *dummy3)
 	}
 	free(buf);
 
-	if((s = socket(AF_INET, proto, 0)) < 0)
+	if((s = socket(ss.ss_family, proto, 0)) < 0)
 		return -1;
 		
 	if(local){
@@ -74,7 +85,7 @@ p9dial(char *addr, char *local, char *dummy2, int *dummy3)
 			close(s);
 			return -1;
 		}
-		if(p9dialparse(buf, &net, &unix, &host, &port) < 0){
+		if(p9dialparse(buf, &net, &unix, &ss, &port) < 0){
 		badlocal:
 			free(buf);
 			close(s);
@@ -84,29 +95,21 @@ p9dial(char *addr, char *local, char *dummy2, int *dummy3)
 			werrstr("bad local address %s for dial %s", local, addr);
 			goto badlocal;
 		}
-		memset(&sal, 0, sizeof sal);
-		memmove(&sal.sin_addr, &host, 4);
-		sal.sin_family = AF_INET;
-		sal.sin_port = htons(port);
 		sn = sizeof n;
 		if(port && getsockopt(s, SOL_SOCKET, SO_TYPE, (void*)&n, &sn) >= 0
 		&& n == SOCK_STREAM){
 			n = 1;
 			setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char*)&n, sizeof n);
 		}
-		if(bind(s, (struct sockaddr*)&sal, sizeof sal) < 0)
+		if(bind(s, (struct sockaddr*)&ssl, sizeof ssl) < 0)
 			goto badlocal;
 		free(buf);
 	}
 
 	n = 1;
 	setsockopt(s, SOL_SOCKET, SO_BROADCAST, &n, sizeof n);
-	if(host != 0){
-		memset(&sa, 0, sizeof sa);
-		memmove(&sa.sin_addr, &host, 4);
-		sa.sin_family = AF_INET;
-		sa.sin_port = htons(port);
-		if(connect(s, (struct sockaddr*)&sa, sizeof sa) < 0){
+	if(!isany(&ss)){
+		if(connect(s, (struct sockaddr*)&ss, sizeof ss) < 0){
 			close(s);
 			return -1;
 		}
@@ -126,21 +129,13 @@ Unix:
 	/* Allow regular files in addition to Unix sockets. */
 	if((s = open(unix, ORDWR)) >= 0)
 		return s;
-	memset(&su, 0, sizeof su);
-	su.sun_family = AF_UNIX;
-	if(strlen(unix)+1 > sizeof su.sun_path){
-		werrstr("unix socket name too long");
-		free(buf);
-		return -1;
-	}
-	strcpy(su.sun_path, unix);
 	free(buf);
-	if((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0){
+	if((s = socket(ss.ss_family, SOCK_STREAM, 0)) < 0){
 		werrstr("socket: %r");
 		return -1;
 	}
-	if(connect(s, (struct sockaddr*)&su, sizeof su) < 0){
-		werrstr("connect %s: %r", su.sun_path);
+	if(connect(s, (struct sockaddr*)&ss, sizeof (struct sockaddr_un)) < 0){
+		werrstr("connect %s: %r", ((struct sockaddr_un*)&ss)->sun_path);
 		close(s);
 		return -1;
 	}