SUNRPC: add support for IPv6 to the kernel's rpcbind client

Prepare for adding IPv6 support to the RPC client by adding IPv6
capabilities to rpcbind.  Note that this is support on the query side
only; registering IPv6 addresses with the local portmapper will come
later.

Note we have to take care not to fall back to using version 2 of the
rpcbind protocol if we're dealing with IPv6 address.  Version 2 doesn't
support IPv6 at all.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: Aurelien Charbon <aurelien.charbon@ext.bull.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/rpcb_clnt.c

@@ -16,6 +16,8 @@
 
 #include <linux/types.h>
 #include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/in6.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
 
@@ -137,10 +139,13 @@ struct rpcbind_args {
 static struct rpc_procinfo rpcb_procedures2[];
 static struct rpc_procinfo rpcb_procedures3[];
 
-static struct rpcb_info {
+struct rpcb_info {
 	int			rpc_vers;
 	struct rpc_procinfo *	rpc_proc;
-} rpcb_next_version[];
+};
+
+static struct rpcb_info rpcb_next_version[];
+static struct rpcb_info rpcb_next_version6[];
 
 static void rpcb_getport_prepare(struct rpc_task *task, void *calldata)
 {
@@ -190,7 +195,17 @@ static struct rpc_clnt *rpcb_create(char *hostname, struct sockaddr *srvaddr,
 				   RPC_CLNT_CREATE_INTR),
 	};
 
-	((struct sockaddr_in *)srvaddr)->sin_port = htons(RPCBIND_PORT);
+	switch (srvaddr->sa_family) {
+	case AF_INET:
+		((struct sockaddr_in *)srvaddr)->sin_port = htons(RPCBIND_PORT);
+		break;
+	case AF_INET6:
+		((struct sockaddr_in6 *)srvaddr)->sin6_port = htons(RPCBIND_PORT);
+		break;
+	default:
+		return NULL;
+	}
+
 	if (!privileged)
 		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 	return rpc_create(&args);
@@ -316,6 +331,7 @@ void rpcb_getport_async(struct rpc_task *task)
 	struct rpc_task	*child;
 	struct sockaddr addr;
 	int status;
+	struct rpcb_info *info;
 
 	dprintk("RPC: %5u %s(%s, %u, %u, %d)\n",
 		task->tk_pid, __FUNCTION__,
@@ -343,14 +359,30 @@ void rpcb_getport_async(struct rpc_task *task)
 		goto bailout_nofree;
 	}
 
-	if (rpcb_next_version[xprt->bind_index].rpc_proc == NULL) {
+	rpc_peeraddr(clnt, (void *)&addr, sizeof(addr));
+
+	/* Don't ever use rpcbind v2 for AF_INET6 requests */
+	switch (addr.sa_family) {
+	case AF_INET:
+		info = rpcb_next_version;
+		break;
+	case AF_INET6:
+		info = rpcb_next_version6;
+		break;
+	default:
+		status = -EAFNOSUPPORT;
+		dprintk("RPC: %5u %s: bad address family\n",
+				task->tk_pid, __FUNCTION__);
+		goto bailout_nofree;
+	}
+	if (info[xprt->bind_index].rpc_proc == NULL) {
 		xprt->bind_index = 0;
 		status = -EACCES;	/* tell caller to try again later */
 		dprintk("RPC: %5u %s: no more getport versions available\n",
 			task->tk_pid, __FUNCTION__);
 		goto bailout_nofree;
 	}
-	bind_version = rpcb_next_version[xprt->bind_index].rpc_vers;
+	bind_version = info[xprt->bind_index].rpc_vers;
 
 	dprintk("RPC: %5u %s: trying rpcbind version %u\n",
 		task->tk_pid, __FUNCTION__, bind_version);
@@ -373,7 +405,6 @@ void rpcb_getport_async(struct rpc_task *task)
 			sizeof(map->r_addr));
 	map->r_owner = RPCB_OWNER_STRING;	/* ignored for GETADDR */
 
-	rpc_peeraddr(clnt, (void *)&addr, sizeof(addr));
 	rpcb_clnt = rpcb_create(clnt->cl_server, &addr, xprt->prot, bind_version, 0);
 	if (IS_ERR(rpcb_clnt)) {
 		status = PTR_ERR(rpcb_clnt);
@@ -594,6 +625,14 @@ static struct rpcb_info rpcb_next_version[] = {
 	{ 0, NULL },
 };
 
+static struct rpcb_info rpcb_next_version6[] = {
+#ifdef CONFIG_SUNRPC_BIND34
+	{ 4, &rpcb_procedures4[RPCBPROC_GETVERSADDR] },
+	{ 3, &rpcb_procedures3[RPCBPROC_GETADDR] },
+#endif
+	{ 0, NULL },
+};
+
 static struct rpc_version rpcb_version2 = {
 	.number		= 2,
 	.nrprocs	= RPCB_HIGHPROC_2,