From: David Howells dhowells@redhat.com
[ Upstream commit 33912c2639ad76660988c8ca97e4d18fca89b668 ]
Allow the list of in-use local UDP endpoints in the current network namespace to be viewed in /proc.
To aid with this, the endpoint list is converted to an hlist and RCU-safe manipulation is used so that the list can be read with only the RCU read lock held.
Signed-off-by: David Howells dhowells@redhat.com cc: Marc Dionne marc.dionne@auristor.com cc: linux-afs@lists.infradead.org Signed-off-by: David S. Miller davem@davemloft.net Stable-dep-of: 3bcd6c7eaa53 ("rxrpc: Fix race between conn bundle lookup and bundle removal [ZDI-CAN-15975]") Signed-off-by: Sasha Levin sashal@kernel.org --- net/rxrpc/ar-internal.h | 5 +-- net/rxrpc/local_object.c | 37 +++++++++++---------- net/rxrpc/net_ns.c | 5 ++- net/rxrpc/proc.c | 69 ++++++++++++++++++++++++++++++++++++++++ 4 files changed, 94 insertions(+), 22 deletions(-)
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index f2e3fb77a02d..38dd63169aac 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -88,7 +88,7 @@ struct rxrpc_net { struct work_struct client_conn_reaper; struct timer_list client_conn_reap_timer;
- struct list_head local_endpoints; + struct hlist_head local_endpoints; struct mutex local_mutex; /* Lock for ->local_endpoints */
DECLARE_HASHTABLE (peer_hash, 10); @@ -281,7 +281,7 @@ struct rxrpc_local { atomic_t active_users; /* Number of users of the local endpoint */ atomic_t usage; /* Number of references to the structure */ struct rxrpc_net *rxnet; /* The network ns in which this resides */ - struct list_head link; + struct hlist_node link; struct socket *socket; /* my UDP socket */ struct work_struct processor; struct rxrpc_sock __rcu *service; /* Service(s) listening on this endpoint */ @@ -1016,6 +1016,7 @@ void rxrpc_put_peer_locked(struct rxrpc_peer *); extern const struct seq_operations rxrpc_call_seq_ops; extern const struct seq_operations rxrpc_connection_seq_ops; extern const struct seq_operations rxrpc_peer_seq_ops; +extern const struct seq_operations rxrpc_local_seq_ops;
/* * recvmsg.c diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c index 1d15940f61d7..0cbbbbcf490e 100644 --- a/net/rxrpc/local_object.c +++ b/net/rxrpc/local_object.c @@ -82,7 +82,7 @@ static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet, atomic_set(&local->usage, 1); atomic_set(&local->active_users, 1); local->rxnet = rxnet; - INIT_LIST_HEAD(&local->link); + INIT_HLIST_NODE(&local->link); INIT_WORK(&local->processor, rxrpc_local_processor); init_rwsem(&local->defrag_sem); skb_queue_head_init(&local->reject_queue); @@ -181,7 +181,7 @@ struct rxrpc_local *rxrpc_lookup_local(struct net *net, { struct rxrpc_local *local; struct rxrpc_net *rxnet = rxrpc_net(net); - struct list_head *cursor; + struct hlist_node *cursor; const char *age; long diff; int ret; @@ -191,16 +191,12 @@ struct rxrpc_local *rxrpc_lookup_local(struct net *net,
mutex_lock(&rxnet->local_mutex);
- for (cursor = rxnet->local_endpoints.next; - cursor != &rxnet->local_endpoints; - cursor = cursor->next) { - local = list_entry(cursor, struct rxrpc_local, link); + hlist_for_each(cursor, &rxnet->local_endpoints) { + local = hlist_entry(cursor, struct rxrpc_local, link);
diff = rxrpc_local_cmp_key(local, srx); - if (diff < 0) + if (diff != 0) continue; - if (diff > 0) - break;
/* Services aren't allowed to share transport sockets, so * reject that here. It is possible that the object is dying - @@ -212,9 +208,10 @@ struct rxrpc_local *rxrpc_lookup_local(struct net *net, goto addr_in_use; }
- /* Found a match. We replace a dying object. Attempting to - * bind the transport socket may still fail if we're attempting - * to use a local address that the dying object is still using. + /* Found a match. We want to replace a dying object. + * Attempting to bind the transport socket may still fail if + * we're attempting to use a local address that the dying + * object is still using. */ if (!rxrpc_use_local(local)) break; @@ -231,10 +228,12 @@ struct rxrpc_local *rxrpc_lookup_local(struct net *net, if (ret < 0) goto sock_error;
- if (cursor != &rxnet->local_endpoints) - list_replace_init(cursor, &local->link); - else - list_add_tail(&local->link, cursor); + if (cursor) { + hlist_replace_rcu(cursor, &local->link); + cursor->pprev = NULL; + } else { + hlist_add_head_rcu(&local->link, &rxnet->local_endpoints); + } age = "new";
found: @@ -375,7 +374,7 @@ static void rxrpc_local_destroyer(struct rxrpc_local *local) local->dead = true;
mutex_lock(&rxnet->local_mutex); - list_del_init(&local->link); + hlist_del_init_rcu(&local->link); mutex_unlock(&rxnet->local_mutex);
rxrpc_clean_up_local_conns(local); @@ -462,9 +461,9 @@ void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet)
flush_workqueue(rxrpc_workqueue);
- if (!list_empty(&rxnet->local_endpoints)) { + if (!hlist_empty(&rxnet->local_endpoints)) { mutex_lock(&rxnet->local_mutex); - list_for_each_entry(local, &rxnet->local_endpoints, link) { + hlist_for_each_entry(local, &rxnet->local_endpoints, link) { pr_err("AF_RXRPC: Leaked local %p {%d}\n", local, atomic_read(&local->usage)); } diff --git a/net/rxrpc/net_ns.c b/net/rxrpc/net_ns.c index e4d6d432515b..bb4c25d6df64 100644 --- a/net/rxrpc/net_ns.c +++ b/net/rxrpc/net_ns.c @@ -72,7 +72,7 @@ static __net_init int rxrpc_init_net(struct net *net) timer_setup(&rxnet->client_conn_reap_timer, rxrpc_client_conn_reap_timeout, 0);
- INIT_LIST_HEAD(&rxnet->local_endpoints); + INIT_HLIST_HEAD(&rxnet->local_endpoints); mutex_init(&rxnet->local_mutex);
hash_init(rxnet->peer_hash); @@ -98,6 +98,9 @@ static __net_init int rxrpc_init_net(struct net *net) proc_create_net("peers", 0444, rxnet->proc_net, &rxrpc_peer_seq_ops, sizeof(struct seq_net_private)); + proc_create_net("locals", 0444, rxnet->proc_net, + &rxrpc_local_seq_ops, + sizeof(struct seq_net_private)); return 0;
err_proc: diff --git a/net/rxrpc/proc.c b/net/rxrpc/proc.c index 5a67955cc00f..7d007a66eba5 100644 --- a/net/rxrpc/proc.c +++ b/net/rxrpc/proc.c @@ -328,3 +328,72 @@ const struct seq_operations rxrpc_peer_seq_ops = { .stop = rxrpc_peer_seq_stop, .show = rxrpc_peer_seq_show, }; + +/* + * Generate a list of extant virtual local endpoints in /proc/net/rxrpc/locals + */ +static int rxrpc_local_seq_show(struct seq_file *seq, void *v) +{ + struct rxrpc_local *local; + char lbuff[50]; + + if (v == SEQ_START_TOKEN) { + seq_puts(seq, + "Proto Local " + " Use Act\n"); + return 0; + } + + local = hlist_entry(v, struct rxrpc_local, link); + + sprintf(lbuff, "%pISpc", &local->srx.transport); + + seq_printf(seq, + "UDP %-47.47s %3u %3u\n", + lbuff, + atomic_read(&local->usage), + atomic_read(&local->active_users)); + + return 0; +} + +static void *rxrpc_local_seq_start(struct seq_file *seq, loff_t *_pos) + __acquires(rcu) +{ + struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq)); + unsigned int n; + + rcu_read_lock(); + + if (*_pos >= UINT_MAX) + return NULL; + + n = *_pos; + if (n == 0) + return SEQ_START_TOKEN; + + return seq_hlist_start_rcu(&rxnet->local_endpoints, n - 1); +} + +static void *rxrpc_local_seq_next(struct seq_file *seq, void *v, loff_t *_pos) +{ + struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq)); + + if (*_pos >= UINT_MAX) + return NULL; + + return seq_hlist_next_rcu(v, &rxnet->local_endpoints, _pos); +} + +static void rxrpc_local_seq_stop(struct seq_file *seq, void *v) + __releases(rcu) +{ + rcu_read_unlock(); +} + +const struct seq_operations rxrpc_local_seq_ops = { + .start = rxrpc_local_seq_start, + .next = rxrpc_local_seq_next, + .stop = rxrpc_local_seq_stop, + .show = rxrpc_local_seq_show, +};