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The sockaddr_in and sockaddr_un structures have been replaced
by sockaddr_storage to handle Unix, IPv4 and IPv6 sockets.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

1 files changed, 53 insertions, 52 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;