diff options
Diffstat (limited to 'net/rxrpc/local_object.c')
| -rw-r--r-- | net/rxrpc/local_object.c | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c new file mode 100644 index 000000000000..a753796fbe8f --- /dev/null +++ b/net/rxrpc/local_object.c @@ -0,0 +1,390 @@ +/* Local endpoint object management + * + * Copyright (C) 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 Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, 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/slab.h> +#include <linux/udp.h> +#include <linux/ip.h> +#include <linux/hashtable.h> +#include <net/sock.h> +#include <net/af_rxrpc.h> +#include "ar-internal.h" + +static void rxrpc_local_processor(struct work_struct *); +static void rxrpc_local_rcu(struct rcu_head *); + +static DEFINE_MUTEX(rxrpc_local_mutex); +static LIST_HEAD(rxrpc_local_endpoints); + +/* + * Compare a local to an address. Return -ve, 0 or +ve to indicate less than, + * same or greater than. + * + * We explicitly don't compare the RxRPC service ID as we want to reject + * conflicting uses by differing services. Further, we don't want to share + * addresses with different options (IPv6), so we don't compare those bits + * either. + */ +static long rxrpc_local_cmp_key(const struct rxrpc_local *local, + const struct sockaddr_rxrpc *srx) +{ + long diff; + + diff = ((local->srx.transport_type - srx->transport_type) ?: + (local->srx.transport_len - srx->transport_len) ?: + (local->srx.transport.family - srx->transport.family)); + if (diff != 0) + return diff; + + switch (srx->transport.family) { + case AF_INET: + /* If the choice of UDP port is left up to the transport, then + * the endpoint record doesn't match. + */ + return ((u16 __force)local->srx.transport.sin.sin_port - + (u16 __force)srx->transport.sin.sin_port) ?: + memcmp(&local->srx.transport.sin.sin_addr, + &srx->transport.sin.sin_addr, + sizeof(struct in_addr)); + default: + BUG(); + } +} + +/* + * Allocate a new local endpoint. + */ +static struct rxrpc_local *rxrpc_alloc_local(const struct sockaddr_rxrpc *srx) +{ + struct rxrpc_local *local; + + local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL); + if (local) { + atomic_set(&local->usage, 1); + INIT_LIST_HEAD(&local->link); + INIT_WORK(&local->processor, rxrpc_local_processor); + INIT_LIST_HEAD(&local->services); + init_rwsem(&local->defrag_sem); + skb_queue_head_init(&local->accept_queue); + skb_queue_head_init(&local->reject_queue); + skb_queue_head_init(&local->event_queue); + local->client_conns = RB_ROOT; + spin_lock_init(&local->client_conns_lock); + spin_lock_init(&local->lock); + rwlock_init(&local->services_lock); + 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_mutex locked + */ +static int rxrpc_open_socket(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(&init_net, 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 %d", ret); + 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; + } + + /* 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_error_report; + _leave(" = 0"); + return 0; + +error: + kernel_sock_shutdown(local->socket, SHUT_RDWR); + local->socket->sk->sk_user_data = NULL; + sock_release(local->socket); + local->socket = NULL; + + _leave(" = %d", ret); + return ret; +} + +/* + * Look up or create a new local endpoint using the specified local address. + */ +struct rxrpc_local *rxrpc_lookup_local(const struct sockaddr_rxrpc *srx) +{ + struct rxrpc_local *local; + struct list_head *cursor; + const char *age; + long diff; + int ret; + + if (srx->transport.family == AF_INET) { + _enter("{%d,%u,%pI4+%hu}", + srx->transport_type, + srx->transport.family, + &srx->transport.sin.sin_addr, + ntohs(srx->transport.sin.sin_port)); + } else { + _enter("{%d,%u}", + srx->transport_type, + srx->transport.family); + return ERR_PTR(-EAFNOSUPPORT); + } + + mutex_lock(&rxrpc_local_mutex); + + for (cursor = rxrpc_local_endpoints.next; + cursor != &rxrpc_local_endpoints; + cursor = cursor->next) { + local = list_entry(cursor, struct rxrpc_local, link); + + diff = rxrpc_local_cmp_key(local, srx); + if (diff < 0) + continue; + if (diff > 0) + break; + + /* Services aren't allowed to share transport sockets, so + * reject that here. It is possible that the object is dying - + * but it may also still have the local transport address that + * we want bound. + */ + if (srx->srx_service) { + local = NULL; + goto addr_in_use; + } + + /* Found a match. We replace a dying object. Attempting to + * bind the transport socket may still fail if we're attempting + * to use a local address that the dying object is still using. + */ + if (!rxrpc_get_local_maybe(local)) { + cursor = cursor->next; + list_del_init(&local->link); + break; + } + + age = "old"; + goto found; + } + + local = rxrpc_alloc_local(srx); + if (!local) + goto nomem; + + ret = rxrpc_open_socket(local); + if (ret < 0) + goto sock_error; + + list_add_tail(&local->link, cursor); + age = "new"; + +found: + mutex_unlock(&rxrpc_local_mutex); + + _net("LOCAL %s %d {%d,%u,%pI4+%hu}", + age, + local->debug_id, + local->srx.transport_type, + local->srx.transport.family, + &local->srx.transport.sin.sin_addr, + ntohs(local->srx.transport.sin.sin_port)); + + _leave(" = %p", local); + return local; + +nomem: + ret = -ENOMEM; +sock_error: + mutex_unlock(&rxrpc_local_mutex); + kfree(local); + _leave(" = %d", ret); + return ERR_PTR(ret); + +addr_in_use: + mutex_unlock(&rxrpc_local_mutex); + _leave(" = -EADDRINUSE"); + return ERR_PTR(-EADDRINUSE); +} + +/* + * A local endpoint reached its end of life. + */ +void __rxrpc_put_local(struct rxrpc_local *local) +{ + _enter("%d", local->debug_id); + rxrpc_queue_work(&local->processor); +} + +/* + * Destroy a local endpoint's socket and then hand the record to RCU to dispose + * of. + * + * Closing the socket cannot be done from bottom half context or RCU callback + * context because it might sleep. + */ +static void rxrpc_local_destroyer(struct rxrpc_local *local) +{ + struct socket *socket = local->socket; + + _enter("%d", local->debug_id); + + /* We can get a race between an incoming call packet queueing the + * processor again and the work processor starting the destruction + * process which will shut down the UDP socket. + */ + if (local->dead) { + _leave(" [already dead]"); + return; + } + local->dead = true; + + mutex_lock(&rxrpc_local_mutex); + list_del_init(&local->link); + mutex_unlock(&rxrpc_local_mutex); + + ASSERT(RB_EMPTY_ROOT(&local->client_conns)); + ASSERT(list_empty(&local->services)); + + if (socket) { + local->socket = NULL; + kernel_sock_shutdown(socket, SHUT_RDWR); + socket->sk->sk_user_data = NULL; + sock_release(socket); + } + + /* At this point, there should be no more packets coming in to the + * local endpoint. + */ + rxrpc_purge_queue(&local->accept_queue); + rxrpc_purge_queue(&local->reject_queue); + rxrpc_purge_queue(&local->event_queue); + + _debug("rcu local %d", local->debug_id); + call_rcu(&local->rcu, rxrpc_local_rcu); +} + +/* + * Process events on an endpoint + */ +static void rxrpc_local_processor(struct work_struct *work) +{ + struct rxrpc_local *local = + container_of(work, struct rxrpc_local, processor); + bool again; + + _enter("%d", local->debug_id); + + do { + again = false; + if (atomic_read(&local->usage) == 0) + return rxrpc_local_destroyer(local); + + if (!skb_queue_empty(&local->accept_queue)) { + rxrpc_accept_incoming_calls(local); + again = true; + } + + if (!skb_queue_empty(&local->reject_queue)) { + rxrpc_reject_packets(local); + again = true; + } + + if (!skb_queue_empty(&local->event_queue)) { + rxrpc_process_local_events(local); + again = true; + } + } while (again); +} + +/* + * Destroy a local endpoint after the RCU grace period expires. + */ +static void rxrpc_local_rcu(struct rcu_head *rcu) +{ + struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu); + + _enter("%d", local->debug_id); + + ASSERT(!work_pending(&local->processor)); + + _net("DESTROY LOCAL %d", local->debug_id); + kfree(local); + _leave(""); +} + +/* + * Verify the local endpoint list is empty by this point. + */ +void __exit rxrpc_destroy_all_locals(void) +{ + struct rxrpc_local *local; + + _enter(""); + + flush_workqueue(rxrpc_workqueue); + + if (!list_empty(&rxrpc_local_endpoints)) { + mutex_lock(&rxrpc_local_mutex); + list_for_each_entry(local, &rxrpc_local_endpoints, link) { + pr_err("AF_RXRPC: Leaked local %p {%d}\n", + local, atomic_read(&local->usage)); + } + mutex_unlock(&rxrpc_local_mutex); + BUG(); + } + + rcu_barrier(); +} |