1 files changed, 273 insertions, 0 deletions

diff --git a/net/rxrpc/ar-peer.c b/net/rxrpc/ar-peer.c
new file mode 100644
index 000000000000..69ac355546ae
--- /dev/null
+++ b/net/rxrpc/ar-peer.c
@@ -0,0 +1,273 @@
+/* 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 <net/sock.h>
+#include <net/af_rxrpc.h>
+#include <net/ip.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);
+
+/*
+ * 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));
+
+                peer->mtu = peer->if_mtu = 65535;
+
+                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,%u.%u.%u.%u+%hu}",
+               srx->transport_type,
+               srx->transport_len,
+               NIPQUAD(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;
+
+        list_add_tail(&peer->link, &rxrpc_peers);
+        write_unlock_bh(&rxrpc_peer_lock);
+        new = "new";
+
+success:
+        _net("PEER %s %d {%d,%u,%u.%u.%u.%u+%hu}",
+             new,
+             peer->debug_id,
+             peer->srx.transport_type,
+             peer->srx.transport.family,
+             NIPQUAD(peer->srx.transport.sin.sin_addr),
+             ntohs(peer->srx.transport.sin.sin_port));
+
+        _leave(" = %p {u=%d}", peer, atomic_read(&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 %d", peer->debug_id);
+        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;
+        }
+
+        schedule_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("");
+}