rxrpc: Support network namespacing

Support network namespacing in AF_RXRPC with the following changes:

 (1) All the local endpoint, peer and call lists, locks, counters, etc. are
     moved into the per-namespace record.

 (2) All the connection tracking is moved into the per-namespace record
     with the exception of the client connection ID tree, which is kept
     global so that connection IDs are kept unique per-machine.

 (3) Each namespace gets its own epoch.  This allows each network namespace
     to pretend to be a separate client machine.

 (4) The /proc/net/rxrpc_xxx files are now called /proc/net/rxrpc/xxx and
     the contents reflect the namespace.

fs/afs/ should be okay with this patch as it explicitly requires the current
net namespace to be init_net to permit a mount to proceed at the moment.  It
will, however, need updating so that cells, IP addresses and DNS records are
per-namespace also.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 17 deletions

diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index 47f7f4205653..692110808baa 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -44,8 +44,6 @@ const char *const rxrpc_call_completions[NR__RXRPC_CALL_COMPLETIONS] = {
 };
 
 struct kmem_cache *rxrpc_call_jar;
-LIST_HEAD(rxrpc_calls);
-DEFINE_RWLOCK(rxrpc_call_lock);
 
 static void rxrpc_call_timer_expired(unsigned long _call)
 {
@@ -207,6 +205,7 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
 	__releases(&rx->sk.sk_lock.slock)
 {
 	struct rxrpc_call *call, *xcall;
+	struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
 	struct rb_node *parent, **pp;
 	const void *here = __builtin_return_address(0);
 	int ret;
@@ -255,9 +254,9 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
 
 	write_unlock(&rx->call_lock);
 
-	write_lock(&rxrpc_call_lock);
-	list_add_tail(&call->link, &rxrpc_calls);
-	write_unlock(&rxrpc_call_lock);
+	write_lock(&rxnet->call_lock);
+	list_add_tail(&call->link, &rxnet->calls);
+	write_unlock(&rxnet->call_lock);
 
 	/* From this point on, the call is protected by its own lock. */
 	release_sock(&rx->sk);
@@ -508,6 +507,7 @@ void rxrpc_release_calls_on_socket(struct rxrpc_sock *rx)
  */
 void rxrpc_put_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
 {
+	struct rxrpc_net *rxnet;
 	const void *here = __builtin_return_address(0);
 	int n;
 
@@ -520,9 +520,12 @@ void rxrpc_put_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
 		_debug("call %d dead", call->debug_id);
 		ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
 
-		write_lock(&rxrpc_call_lock);
-		list_del_init(&call->link);
-		write_unlock(&rxrpc_call_lock);
+		if (!list_empty(&call->link)) {
+			rxnet = rxrpc_net(sock_net(&call->socket->sk));
+			write_lock(&rxnet->call_lock);
+			list_del_init(&call->link);
+			write_unlock(&rxnet->call_lock);
+		}
 
 		rxrpc_cleanup_call(call);
 	}
@@ -570,21 +573,23 @@ void rxrpc_cleanup_call(struct rxrpc_call *call)
 }
 
 /*
- * Make sure that all calls are gone.
+ * Make sure that all calls are gone from a network namespace.  To reach this
+ * point, any open UDP sockets in that namespace must have been closed, so any
+ * outstanding calls cannot be doing I/O.
  */
-void __exit rxrpc_destroy_all_calls(void)
+void rxrpc_destroy_all_calls(struct rxrpc_net *rxnet)
 {
 	struct rxrpc_call *call;
 
 	_enter("");
 
-	if (list_empty(&rxrpc_calls))
+	if (list_empty(&rxnet->calls))
 		return;
 
-	write_lock(&rxrpc_call_lock);
+	write_lock(&rxnet->call_lock);
 
-	while (!list_empty(&rxrpc_calls)) {
-		call = list_entry(rxrpc_calls.next, struct rxrpc_call, link);
+	while (!list_empty(&rxnet->calls)) {
+		call = list_entry(rxnet->calls.next, struct rxrpc_call, link);
 		_debug("Zapping call %p", call);
 
 		rxrpc_see_call(call);
@@ -595,10 +600,10 @@ void __exit rxrpc_destroy_all_calls(void)
 		       rxrpc_call_states[call->state],
 		       call->flags, call->events);
 
-		write_unlock(&rxrpc_call_lock);
+		write_unlock(&rxnet->call_lock);
 		cond_resched();
-		write_lock(&rxrpc_call_lock);
+		write_lock(&rxnet->call_lock);
 	}
 
-	write_unlock(&rxrpc_call_lock);
+	write_unlock(&rxnet->call_lock);
 }