-/* RxRPC remote transport endpoint management
+/* RxRPC remote transport endpoint record management
*
- * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
#include <linux/skbuff.h>
#include <linux/udp.h>
#include <linux/in.h>
-#include <linux/in6.h>
-#include <linux/icmp.h>
#include <linux/slab.h>
+#include <linux/hashtable.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
#include <net/route.h>
#include "ar-internal.h"
-static LIST_HEAD(rxrpc_peers);
-static DEFINE_RWLOCK(rxrpc_peer_lock);
-static DECLARE_WAIT_QUEUE_HEAD(rxrpc_peer_wq);
+static DEFINE_HASHTABLE(rxrpc_peer_hash, 10);
+static DEFINE_SPINLOCK(rxrpc_peer_hash_lock);
-static void rxrpc_destroy_peer(struct work_struct *work);
+/*
+ * Hash a peer key.
+ */
+static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local,
+ const struct sockaddr_rxrpc *srx)
+{
+ const u16 *p;
+ unsigned int i, size;
+ unsigned long hash_key;
+
+ _enter("");
+
+ hash_key = (unsigned long)local / __alignof__(*local);
+ hash_key += srx->transport_type;
+ hash_key += srx->transport_len;
+ hash_key += srx->transport.family;
+
+ switch (srx->transport.family) {
+ case AF_INET:
+ hash_key += (u16 __force)srx->transport.sin.sin_port;
+ size = sizeof(srx->transport.sin.sin_addr);
+ p = (u16 *)&srx->transport.sin.sin_addr;
+ break;
+ }
+
+ /* Step through the peer address in 16-bit portions for speed */
+ for (i = 0; i < size; i += sizeof(*p), p++)
+ hash_key += *p;
+
+ _leave(" 0x%lx", hash_key);
+ return hash_key;
+}
+
+/*
+ * Compare a peer to a key. Return -ve, 0 or +ve to indicate less than, same
+ * or greater than.
+ *
+ * Unfortunately, the primitives in linux/hashtable.h don't allow for sorted
+ * buckets and mid-bucket insertion, so we don't make full use of this
+ * information at this point.
+ */
+static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
+ struct rxrpc_local *local,
+ const struct sockaddr_rxrpc *srx,
+ unsigned long hash_key)
+{
+ long diff;
+
+ diff = ((peer->hash_key - hash_key) ?:
+ ((unsigned long)peer->local - (unsigned long)local) ?:
+ (peer->srx.transport_type - srx->transport_type) ?:
+ (peer->srx.transport_len - srx->transport_len) ?:
+ (peer->srx.transport.family - srx->transport.family));
+ if (diff != 0)
+ return diff;
+
+ switch (srx->transport.family) {
+ case AF_INET:
+ return ((u16 __force)peer->srx.transport.sin.sin_port -
+ (u16 __force)srx->transport.sin.sin_port) ?:
+ memcmp(&peer->srx.transport.sin.sin_addr,
+ &srx->transport.sin.sin_addr,
+ sizeof(struct in_addr));
+ default:
+ BUG();
+ }
+}
+
+/*
+ * Look up a remote transport endpoint for the specified address using RCU.
+ */
+static struct rxrpc_peer *__rxrpc_lookup_peer_rcu(
+ struct rxrpc_local *local,
+ const struct sockaddr_rxrpc *srx,
+ unsigned long hash_key)
+{
+ struct rxrpc_peer *peer;
+
+ hash_for_each_possible_rcu(rxrpc_peer_hash, peer, hash_link, hash_key) {
+ if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0) {
+ if (atomic_read(&peer->usage) == 0)
+ return NULL;
+ return peer;
+ }
+ }
+
+ return NULL;
+}
+
+/*
+ * Look up a remote transport endpoint for the specified address using RCU.
+ */
+struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local,
+ const struct sockaddr_rxrpc *srx)
+{
+ struct rxrpc_peer *peer;
+ unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
+
+ peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
+ if (peer) {
+ switch (srx->transport.family) {
+ case AF_INET:
+ _net("PEER %d {%d,%u,%pI4+%hu}",
+ peer->debug_id,
+ peer->srx.transport_type,
+ peer->srx.transport.family,
+ &peer->srx.transport.sin.sin_addr,
+ ntohs(peer->srx.transport.sin.sin_port));
+ break;
+ }
+
+ _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
+ }
+ return peer;
+}
/*
* assess the MTU size for the network interface through which this peer is
}
/*
- * allocate a new peer
+ * Allocate a peer.
*/
-static struct rxrpc_peer *rxrpc_alloc_peer(struct sockaddr_rxrpc *srx,
- gfp_t gfp)
+struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
{
struct rxrpc_peer *peer;
peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
if (peer) {
- INIT_WORK(&peer->destroyer, &rxrpc_destroy_peer);
- INIT_LIST_HEAD(&peer->link);
+ atomic_set(&peer->usage, 1);
+ peer->local = local;
INIT_LIST_HEAD(&peer->error_targets);
spin_lock_init(&peer->lock);
- atomic_set(&peer->usage, 1);
peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
+ }
+
+ _leave(" = %p", peer);
+ return peer;
+}
+
+/*
+ * Set up a new peer.
+ */
+static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local,
+ struct sockaddr_rxrpc *srx,
+ unsigned long hash_key,
+ gfp_t gfp)
+{
+ struct rxrpc_peer *peer;
+
+ _enter("");
+
+ peer = rxrpc_alloc_peer(local, gfp);
+ if (peer) {
+ peer->hash_key = hash_key;
memcpy(&peer->srx, srx, sizeof(*srx));
rxrpc_assess_MTU_size(peer);
/*
* obtain a remote transport endpoint for the specified address
*/
-struct rxrpc_peer *rxrpc_get_peer(struct sockaddr_rxrpc *srx, gfp_t gfp)
+struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
+ struct sockaddr_rxrpc *srx, gfp_t gfp)
{
struct rxrpc_peer *peer, *candidate;
- const char *new = "old";
- int usage;
+ unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
_enter("{%d,%d,%pI4+%hu}",
srx->transport_type,
ntohs(srx->transport.sin.sin_port));
/* search the peer list first */
- read_lock_bh(&rxrpc_peer_lock);
- list_for_each_entry(peer, &rxrpc_peers, link) {
- _debug("check PEER %d { u=%d t=%d l=%d }",
- peer->debug_id,
- atomic_read(&peer->usage),
- peer->srx.transport_type,
- peer->srx.transport_len);
-
- if (atomic_read(&peer->usage) > 0 &&
- peer->srx.transport_type == srx->transport_type &&
- peer->srx.transport_len == srx->transport_len &&
- memcmp(&peer->srx.transport,
- &srx->transport,
- srx->transport_len) == 0)
- goto found_extant_peer;
- }
- read_unlock_bh(&rxrpc_peer_lock);
-
- /* not yet present - create a candidate for a new record and then
- * redo the search */
- candidate = rxrpc_alloc_peer(srx, gfp);
- if (!candidate) {
- _leave(" = -ENOMEM");
- return ERR_PTR(-ENOMEM);
- }
+ rcu_read_lock();
+ peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
+ if (peer && !rxrpc_get_peer_maybe(peer))
+ peer = NULL;
+ rcu_read_unlock();
+
+ if (!peer) {
+ /* The peer is not yet present in hash - create a candidate
+ * for a new record and then redo the search.
+ */
+ candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
+ if (!candidate) {
+ _leave(" = NULL [nomem]");
+ return NULL;
+ }
- write_lock_bh(&rxrpc_peer_lock);
+ spin_lock(&rxrpc_peer_hash_lock);
- list_for_each_entry(peer, &rxrpc_peers, link) {
- if (atomic_read(&peer->usage) > 0 &&
- peer->srx.transport_type == srx->transport_type &&
- peer->srx.transport_len == srx->transport_len &&
- memcmp(&peer->srx.transport,
- &srx->transport,
- srx->transport_len) == 0)
- goto found_extant_second;
- }
+ /* Need to check that we aren't racing with someone else */
+ peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
+ if (peer && !rxrpc_get_peer_maybe(peer))
+ peer = NULL;
+ if (!peer)
+ hash_add_rcu(rxrpc_peer_hash,
+ &candidate->hash_link, hash_key);
- /* we can now add the new candidate to the list */
- peer = candidate;
- candidate = NULL;
- usage = atomic_read(&peer->usage);
+ spin_unlock(&rxrpc_peer_hash_lock);
- list_add_tail(&peer->link, &rxrpc_peers);
- write_unlock_bh(&rxrpc_peer_lock);
- new = "new";
+ if (peer)
+ kfree(candidate);
+ else
+ peer = candidate;
+ }
-success:
- _net("PEER %s %d {%d,%u,%pI4+%hu}",
- new,
+ _net("PEER %d {%d,%pI4+%hu}",
peer->debug_id,
peer->srx.transport_type,
- peer->srx.transport.family,
&peer->srx.transport.sin.sin_addr,
ntohs(peer->srx.transport.sin.sin_port));
- _leave(" = %p {u=%d}", peer, usage);
- return peer;
-
- /* we found the peer in the list immediately */
-found_extant_peer:
- usage = atomic_inc_return(&peer->usage);
- read_unlock_bh(&rxrpc_peer_lock);
- goto success;
-
- /* we found the peer on the second time through the list */
-found_extant_second:
- usage = atomic_inc_return(&peer->usage);
- write_unlock_bh(&rxrpc_peer_lock);
- kfree(candidate);
- goto success;
-}
-
-/*
- * find the peer associated with a packet
- */
-struct rxrpc_peer *rxrpc_find_peer(struct rxrpc_local *local,
- __be32 addr, __be16 port)
-{
- struct rxrpc_peer *peer;
-
- _enter("");
-
- /* search the peer list */
- read_lock_bh(&rxrpc_peer_lock);
-
- if (local->srx.transport.family == AF_INET &&
- local->srx.transport_type == SOCK_DGRAM
- ) {
- list_for_each_entry(peer, &rxrpc_peers, link) {
- if (atomic_read(&peer->usage) > 0 &&
- peer->srx.transport_type == SOCK_DGRAM &&
- peer->srx.transport.family == AF_INET &&
- peer->srx.transport.sin.sin_port == port &&
- peer->srx.transport.sin.sin_addr.s_addr == addr)
- goto found_UDP_peer;
- }
-
- goto new_UDP_peer;
- }
-
- read_unlock_bh(&rxrpc_peer_lock);
- _leave(" = -EAFNOSUPPORT");
- return ERR_PTR(-EAFNOSUPPORT);
-
-found_UDP_peer:
- _net("Rx UDP DGRAM from peer %d", peer->debug_id);
- atomic_inc(&peer->usage);
- read_unlock_bh(&rxrpc_peer_lock);
- _leave(" = %p", peer);
+ _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
return peer;
-
-new_UDP_peer:
- _net("Rx UDP DGRAM from NEW peer");
- read_unlock_bh(&rxrpc_peer_lock);
- _leave(" = -EBUSY [new]");
- return ERR_PTR(-EBUSY);
}
/*
- * release a remote transport endpoint
+ * Discard a ref on a remote peer record.
*/
-void rxrpc_put_peer(struct rxrpc_peer *peer)
+void __rxrpc_put_peer(struct rxrpc_peer *peer)
{
- _enter("%p{u=%d}", peer, atomic_read(&peer->usage));
+ ASSERT(list_empty(&peer->error_targets));
- ASSERTCMP(atomic_read(&peer->usage), >, 0);
-
- if (likely(!atomic_dec_and_test(&peer->usage))) {
- _leave(" [in use]");
- return;
- }
-
- rxrpc_queue_work(&peer->destroyer);
- _leave("");
-}
-
-/*
- * destroy a remote transport endpoint
- */
-static void rxrpc_destroy_peer(struct work_struct *work)
-{
- struct rxrpc_peer *peer =
- container_of(work, struct rxrpc_peer, destroyer);
-
- _enter("%p{%d}", peer, atomic_read(&peer->usage));
-
- write_lock_bh(&rxrpc_peer_lock);
- list_del(&peer->link);
- write_unlock_bh(&rxrpc_peer_lock);
-
- _net("DESTROY PEER %d", peer->debug_id);
- kfree(peer);
-
- if (list_empty(&rxrpc_peers))
- wake_up_all(&rxrpc_peer_wq);
- _leave("");
-}
-
-/*
- * preemptively destroy all the peer records from a transport endpoint rather
- * than waiting for them to time out
- */
-void __exit rxrpc_destroy_all_peers(void)
-{
- DECLARE_WAITQUEUE(myself,current);
-
- _enter("");
-
- /* we simply have to wait for them to go away */
- if (!list_empty(&rxrpc_peers)) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- add_wait_queue(&rxrpc_peer_wq, &myself);
-
- while (!list_empty(&rxrpc_peers)) {
- schedule();
- set_current_state(TASK_UNINTERRUPTIBLE);
- }
-
- remove_wait_queue(&rxrpc_peer_wq, &myself);
- set_current_state(TASK_RUNNING);
- }
+ spin_lock(&rxrpc_peer_hash_lock);
+ hash_del_rcu(&peer->hash_link);
+ spin_unlock(&rxrpc_peer_hash_lock);
- _leave("");
+ kfree_rcu(peer, rcu);
}
projects / deliverable / linux.git / blobdiff