1 files changed, 309 insertions, 0 deletions

diff --git a/net/rxrpc/ar-local.c b/net/rxrpc/ar-local.c
new file mode 100644
index 000000000000..a20a2c0fe105
--- /dev/null
+++ b/net/rxrpc/ar-local.c
@@ -0,0 +1,309 @@
+/* AF_RXRPC local 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 <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+static LIST_HEAD(rxrpc_locals);
+DEFINE_RWLOCK(rxrpc_local_lock);
+static DECLARE_RWSEM(rxrpc_local_sem);
+static DECLARE_WAIT_QUEUE_HEAD(rxrpc_local_wq);
+
+static void rxrpc_destroy_local(struct work_struct *work);
+
+/*
+ * allocate a new local
+ */
+static
+struct rxrpc_local *rxrpc_alloc_local(struct sockaddr_rxrpc *srx)
+{
+        struct rxrpc_local *local;
+
+        local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
+        if (local) {
+                INIT_WORK(&local->destroyer, &rxrpc_destroy_local);
+                INIT_WORK(&local->acceptor, &rxrpc_accept_incoming_calls);
+                INIT_WORK(&local->rejecter, &rxrpc_reject_packets);
+                INIT_LIST_HEAD(&local->services);
+                INIT_LIST_HEAD(&local->link);
+                init_rwsem(&local->defrag_sem);
+                skb_queue_head_init(&local->accept_queue);
+                skb_queue_head_init(&local->reject_queue);
+                spin_lock_init(&local->lock);
+                rwlock_init(&local->services_lock);
+                atomic_set(&local->usage, 1);
+                local->debug_id = atomic_inc_return(&rxrpc_debug_id);
+                memcpy(&local->srx, srx, sizeof(*srx));
+        }
+
+        _leave(" = %p", local);
+        return local;
+}
+
+/*
+ * create the local socket
+ * - must be called with rxrpc_local_sem writelocked
+ */
+static int rxrpc_create_local(struct rxrpc_local *local)
+{
+        struct sock *sock;
+        int ret, opt;
+
+        _enter("%p{%d}", local, local->srx.transport_type);
+
+        /* create a socket to represent the local endpoint */
+        ret = sock_create_kern(PF_INET, local->srx.transport_type, IPPROTO_UDP,
+                               &local->socket);
+        if (ret < 0) {
+                _leave(" = %d [socket]", ret);
+                return ret;
+        }
+
+        /* if a local address was supplied then bind it */
+        if (local->srx.transport_len > sizeof(sa_family_t)) {
+                _debug("bind");
+                ret = kernel_bind(local->socket,
+                                  (struct sockaddr *) &local->srx.transport,
+                                  local->srx.transport_len);
+                if (ret < 0) {
+                        _debug("bind failed");
+                        goto error;
+                }
+        }
+
+        /* we want to receive ICMP errors */
+        opt = 1;
+        ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
+                                (char *) &opt, sizeof(opt));
+        if (ret < 0) {
+                _debug("setsockopt failed");
+                goto error;
+        }
+
+        /* we want to set the don't fragment bit */
+        opt = IP_PMTUDISC_DO;
+        ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
+                                (char *) &opt, sizeof(opt));
+        if (ret < 0) {
+                _debug("setsockopt failed");
+                goto error;
+        }
+
+        write_lock_bh(&rxrpc_local_lock);
+        list_add(&local->link, &rxrpc_locals);
+        write_unlock_bh(&rxrpc_local_lock);
+
+        /* set the socket up */
+        sock = local->socket->sk;
+        sock->sk_user_data      = local;
+        sock->sk_data_ready     = rxrpc_data_ready;
+        sock->sk_error_report   = rxrpc_UDP_error_report;
+        _leave(" = 0");
+        return 0;
+
+error:
+        local->socket->ops->shutdown(local->socket, 2);
+        local->socket->sk->sk_user_data = NULL;
+        sock_release(local->socket);
+        local->socket = NULL;
+
+        _leave(" = %d", ret);
+        return ret;
+}
+
+/*
+ * create a new local endpoint using the specified UDP address
+ */
+struct rxrpc_local *rxrpc_lookup_local(struct sockaddr_rxrpc *srx)
+{
+        struct rxrpc_local *local;
+        int ret;
+
+        _enter("{%d,%u,%u.%u.%u.%u+%hu}",
+               srx->transport_type,
+               srx->transport.family,
+               NIPQUAD(srx->transport.sin.sin_addr),
+               ntohs(srx->transport.sin.sin_port));
+
+        down_write(&rxrpc_local_sem);
+
+        /* see if we have a suitable local local endpoint already */
+        read_lock_bh(&rxrpc_local_lock);
+
+        list_for_each_entry(local, &rxrpc_locals, link) {
+                _debug("CMP {%d,%u,%u.%u.%u.%u+%hu}",
+                       local->srx.transport_type,
+                       local->srx.transport.family,
+                       NIPQUAD(local->srx.transport.sin.sin_addr),
+                       ntohs(local->srx.transport.sin.sin_port));
+
+                if (local->srx.transport_type != srx->transport_type ||
+                    local->srx.transport.family != srx->transport.family)
+                        continue;
+
+                switch (srx->transport.family) {
+                case AF_INET:
+                        if (local->srx.transport.sin.sin_port !=
+                            srx->transport.sin.sin_port)
+                                continue;
+                        if (memcmp(&local->srx.transport.sin.sin_addr,
+                                   &srx->transport.sin.sin_addr,
+                                   sizeof(struct in_addr)) != 0)
+                                continue;
+                        goto found_local;
+
+                default:
+                        BUG();
+                }
+        }
+
+        read_unlock_bh(&rxrpc_local_lock);
+
+        /* we didn't find one, so we need to create one */
+        local = rxrpc_alloc_local(srx);
+        if (!local) {
+                up_write(&rxrpc_local_sem);
+                return ERR_PTR(-ENOMEM);
+        }
+
+        ret = rxrpc_create_local(local);
+        if (ret < 0) {
+                up_write(&rxrpc_local_sem);
+                kfree(local);
+                _leave(" = %d", ret);
+                return ERR_PTR(ret);
+        }
+
+        up_write(&rxrpc_local_sem);
+
+        _net("LOCAL new %d {%d,%u,%u.%u.%u.%u+%hu}",
+             local->debug_id,
+             local->srx.transport_type,
+             local->srx.transport.family,
+             NIPQUAD(local->srx.transport.sin.sin_addr),
+             ntohs(local->srx.transport.sin.sin_port));
+
+        _leave(" = %p [new]", local);
+        return local;
+
+found_local:
+        rxrpc_get_local(local);
+        read_unlock_bh(&rxrpc_local_lock);
+        up_write(&rxrpc_local_sem);
+
+        _net("LOCAL old %d {%d,%u,%u.%u.%u.%u+%hu}",
+             local->debug_id,
+             local->srx.transport_type,
+             local->srx.transport.family,
+             NIPQUAD(local->srx.transport.sin.sin_addr),
+             ntohs(local->srx.transport.sin.sin_port));
+
+        _leave(" = %p [reuse]", local);
+        return local;
+}
+
+/*
+ * release a local endpoint
+ */
+void rxrpc_put_local(struct rxrpc_local *local)
+{
+        _enter("%p{u=%d}", local, atomic_read(&local->usage));
+
+        ASSERTCMP(atomic_read(&local->usage), >, 0);
+
+        /* to prevent a race, the decrement and the dequeue must be effectively
+         * atomic */
+        write_lock_bh(&rxrpc_local_lock);
+        if (unlikely(atomic_dec_and_test(&local->usage))) {
+                _debug("destroy local");
+                schedule_work(&local->destroyer);
+        }
+        write_unlock_bh(&rxrpc_local_lock);
+        _leave("");
+}
+
+/*
+ * destroy a local endpoint
+ */
+static void rxrpc_destroy_local(struct work_struct *work)
+{
+        struct rxrpc_local *local =
+                container_of(work, struct rxrpc_local, destroyer);
+
+        _enter("%p{%d}", local, atomic_read(&local->usage));
+
+        down_write(&rxrpc_local_sem);
+
+        write_lock_bh(&rxrpc_local_lock);
+        if (atomic_read(&local->usage) > 0) {
+                write_unlock_bh(&rxrpc_local_lock);
+                up_read(&rxrpc_local_sem);
+                _leave(" [resurrected]");
+                return;
+        }
+
+        list_del(&local->link);
+        local->socket->sk->sk_user_data = NULL;
+        write_unlock_bh(&rxrpc_local_lock);
+
+        downgrade_write(&rxrpc_local_sem);
+
+        ASSERT(list_empty(&local->services));
+        ASSERT(!work_pending(&local->acceptor));
+        ASSERT(!work_pending(&local->rejecter));
+
+        /* finish cleaning up the local descriptor */
+        rxrpc_purge_queue(&local->accept_queue);
+        rxrpc_purge_queue(&local->reject_queue);
+        local->socket->ops->shutdown(local->socket, 2);
+        sock_release(local->socket);
+
+        up_read(&rxrpc_local_sem);
+
+        _net("DESTROY LOCAL %d", local->debug_id);
+        kfree(local);
+
+        if (list_empty(&rxrpc_locals))
+                wake_up_all(&rxrpc_local_wq);
+
+        _leave("");
+}
+
+/*
+ * preemptively destroy all local local endpoint rather than waiting for
+ * them to be destroyed
+ */
+void __exit rxrpc_destroy_all_locals(void)
+{
+        DECLARE_WAITQUEUE(myself,current);
+
+        _enter("");
+
+        /* we simply have to wait for them to go away */
+        if (!list_empty(&rxrpc_locals)) {
+                set_current_state(TASK_UNINTERRUPTIBLE);
+                add_wait_queue(&rxrpc_local_wq, &myself);
+
+                while (!list_empty(&rxrpc_locals)) {
+                        schedule();
+                        set_current_state(TASK_UNINTERRUPTIBLE);
+                }
+
+                remove_wait_queue(&rxrpc_local_wq, &myself);
+                set_current_state(TASK_RUNNING);
+        }
+
+        _leave("");
+}