--- /dev/null
+/* RxRPC remote transport endpoint management
+ *
+ * Copyright (C) 2007 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.
+ */
+
+#include <linux/module.h>
+#include <linux/net.h>
+#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 <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 void rxrpc_destroy_peer(struct work_struct *work);
+
+/*
+ * 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 new peer
+ */
+static struct rxrpc_peer *rxrpc_alloc_peer(struct sockaddr_rxrpc *srx,
+ gfp_t gfp)
+{
+ struct rxrpc_peer *peer;
+
+ _enter("");
+
+ peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
+ if (peer) {
+ INIT_WORK(&peer->destroyer, &rxrpc_destroy_peer);
+ INIT_LIST_HEAD(&peer->link);
+ 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);
+ 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_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_get_peer(struct sockaddr_rxrpc *srx, gfp_t gfp)
+{
+ struct rxrpc_peer *peer, *candidate;
+ const char *new = "old";
+ int usage;
+
+ _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 */
+ 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);
+ }
+
+ write_lock_bh(&rxrpc_peer_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;
+ }
+
+ /* we can now add the new candidate to the list */
+ peer = candidate;
+ candidate = NULL;
+ usage = atomic_read(&peer->usage);
+
+ list_add_tail(&peer->link, &rxrpc_peers);
+ write_unlock_bh(&rxrpc_peer_lock);
+ new = "new";
+
+success:
+ _net("PEER %s %d {%d,%u,%pI4+%hu}",
+ new,
+ 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);
+ 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
+ */
+void rxrpc_put_peer(struct rxrpc_peer *peer)
+{
+ _enter("%p{u=%d}", peer, atomic_read(&peer->usage));
+
+ 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);
+ }
+
+ _leave("");
+}
Code Review / kvmfornfv.git / blobdiff