summaryrefslogtreecommitdiffstats
path: root/net/rxrpc/peer_object.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/rxrpc/peer_object.c')
-rw-r--r--net/rxrpc/peer_object.c315
1 files changed, 315 insertions, 0 deletions
diff --git a/net/rxrpc/peer_object.c b/net/rxrpc/peer_object.c
new file mode 100644
index 000000000000..538e9831c699
--- /dev/null
+++ b/net/rxrpc/peer_object.c
@@ -0,0 +1,315 @@
+/* RxRPC remote transport endpoint record management
+ *
+ * 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
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/net.h>
+#include <linux/skbuff.h>
+#include <linux/udp.h>
+#include <linux/in.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 DEFINE_HASHTABLE(rxrpc_peer_hash, 10);
+static DEFINE_SPINLOCK(rxrpc_peer_hash_lock);
+
+/*
+ * 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;
+ default:
+ WARN(1, "AF_RXRPC: Unsupported transport address family\n");
+ return 0;
+ }
+
+ /* 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
+ * reached
+ */
+static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer)
+{
+ struct rtable *rt;
+ struct flowi4 fl4;
+
+ peer->if_mtu = 1500;
+
+ rt = ip_route_output_ports(&init_net, &fl4, NULL,
+ peer->srx.transport.sin.sin_addr.s_addr, 0,
+ htons(7000), htons(7001),
+ IPPROTO_UDP, 0, 0);
+ if (IS_ERR(rt)) {
+ _leave(" [route err %ld]", PTR_ERR(rt));
+ return;
+ }
+
+ peer->if_mtu = dst_mtu(&rt->dst);
+ dst_release(&rt->dst);
+
+ _leave(" [if_mtu %u]", peer->if_mtu);
+}
+
+/*
+ * Allocate a peer.
+ */
+struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
+{
+ struct rxrpc_peer *peer;
+
+ _enter("");
+
+ peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
+ if (peer) {
+ atomic_set(&peer->usage, 1);
+ peer->local = local;
+ INIT_HLIST_HEAD(&peer->error_targets);
+ INIT_WORK(&peer->error_distributor,
+ &rxrpc_peer_error_distributor);
+ peer->service_conns = RB_ROOT;
+ seqlock_init(&peer->service_conn_lock);
+ spin_lock_init(&peer->lock);
+ 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);
+ peer->mtu = peer->if_mtu;
+
+ if (srx->transport.family == AF_INET) {
+ peer->hdrsize = sizeof(struct iphdr);
+ switch (srx->transport_type) {
+ case SOCK_DGRAM:
+ peer->hdrsize += sizeof(struct udphdr);
+ break;
+ default:
+ BUG();
+ break;
+ }
+ } else {
+ BUG();
+ }
+
+ peer->hdrsize += sizeof(struct rxrpc_wire_header);
+ peer->maxdata = peer->mtu - peer->hdrsize;
+ }
+
+ _leave(" = %p", peer);
+ return peer;
+}
+
+/*
+ * obtain a remote transport endpoint for the specified address
+ */
+struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
+ struct sockaddr_rxrpc *srx, gfp_t gfp)
+{
+ struct rxrpc_peer *peer, *candidate;
+ unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
+
+ _enter("{%d,%d,%pI4+%hu}",
+ srx->transport_type,
+ srx->transport_len,
+ &srx->transport.sin.sin_addr,
+ ntohs(srx->transport.sin.sin_port));
+
+ /* search the peer list first */
+ 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;
+ }
+
+ spin_lock(&rxrpc_peer_hash_lock);
+
+ /* 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);
+
+ spin_unlock(&rxrpc_peer_hash_lock);
+
+ if (peer)
+ kfree(candidate);
+ else
+ peer = candidate;
+ }
+
+ _net("PEER %d {%d,%pI4+%hu}",
+ peer->debug_id,
+ peer->srx.transport_type,
+ &peer->srx.transport.sin.sin_addr,
+ ntohs(peer->srx.transport.sin.sin_port));
+
+ _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
+ return peer;
+}
+
+/*
+ * Discard a ref on a remote peer record.
+ */
+void __rxrpc_put_peer(struct rxrpc_peer *peer)
+{
+ ASSERT(hlist_empty(&peer->error_targets));
+
+ spin_lock(&rxrpc_peer_hash_lock);
+ hash_del_rcu(&peer->hash_link);
+ spin_unlock(&rxrpc_peer_hash_lock);
+
+ kfree_rcu(peer, rcu);
+}