diff options
Diffstat (limited to 'net/rxrpc/local_object.c')
| -rw-r--r-- | net/rxrpc/local_object.c | 474 |
1 files changed, 474 insertions, 0 deletions
diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c new file mode 100644 index 000000000..38ea98ff4 --- /dev/null +++ b/net/rxrpc/local_object.c @@ -0,0 +1,474 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Local endpoint object management + * + * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#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/udp.h> +#include <net/udp_tunnel.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 *); + +/* + * 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)); +#ifdef CONFIG_AF_RXRPC_IPV6 + case AF_INET6: + /* If the choice of UDP6 port is left up to the transport, then + * the endpoint record doesn't match. + */ + return ((u16 __force)local->srx.transport.sin6.sin6_port - + (u16 __force)srx->transport.sin6.sin6_port) ?: + memcmp(&local->srx.transport.sin6.sin6_addr, + &srx->transport.sin6.sin6_addr, + sizeof(struct in6_addr)); +#endif + default: + BUG(); + } +} + +/* + * Allocate a new local endpoint. + */ +static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet, + const struct sockaddr_rxrpc *srx) +{ + struct rxrpc_local *local; + + local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL); + if (local) { + refcount_set(&local->ref, 1); + atomic_set(&local->active_users, 1); + local->rxnet = rxnet; + INIT_HLIST_NODE(&local->link); + INIT_WORK(&local->processor, rxrpc_local_processor); + init_rwsem(&local->defrag_sem); + skb_queue_head_init(&local->reject_queue); + skb_queue_head_init(&local->event_queue); + local->client_bundles = RB_ROOT; + spin_lock_init(&local->client_bundles_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)); + local->srx.srx_service = 0; + trace_rxrpc_local(local->debug_id, rxrpc_local_new, 1, NULL); + } + + _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 net *net) +{ + struct udp_tunnel_sock_cfg tuncfg = {NULL}; + struct sockaddr_rxrpc *srx = &local->srx; + struct udp_port_cfg udp_conf = {0}; + struct sock *usk; + int ret; + + _enter("%p{%d,%d}", + local, srx->transport_type, srx->transport.family); + + udp_conf.family = srx->transport.family; + udp_conf.use_udp_checksums = true; + if (udp_conf.family == AF_INET) { + udp_conf.local_ip = srx->transport.sin.sin_addr; + udp_conf.local_udp_port = srx->transport.sin.sin_port; +#if IS_ENABLED(CONFIG_AF_RXRPC_IPV6) + } else { + udp_conf.local_ip6 = srx->transport.sin6.sin6_addr; + udp_conf.local_udp_port = srx->transport.sin6.sin6_port; + udp_conf.use_udp6_tx_checksums = true; + udp_conf.use_udp6_rx_checksums = true; +#endif + } + ret = udp_sock_create(net, &udp_conf, &local->socket); + if (ret < 0) { + _leave(" = %d [socket]", ret); + return ret; + } + + tuncfg.encap_type = UDP_ENCAP_RXRPC; + tuncfg.encap_rcv = rxrpc_input_packet; + tuncfg.encap_err_rcv = rxrpc_encap_err_rcv; + tuncfg.sk_user_data = local; + setup_udp_tunnel_sock(net, local->socket, &tuncfg); + + /* set the socket up */ + usk = local->socket->sk; + usk->sk_error_report = rxrpc_error_report; + + switch (srx->transport.family) { + case AF_INET6: + /* we want to receive ICMPv6 errors */ + ip6_sock_set_recverr(usk); + + /* Fall through and set IPv4 options too otherwise we don't get + * errors from IPv4 packets sent through the IPv6 socket. + */ + fallthrough; + case AF_INET: + /* we want to receive ICMP errors */ + ip_sock_set_recverr(usk); + + /* we want to set the don't fragment bit */ + ip_sock_set_mtu_discover(usk, IP_PMTUDISC_DO); + + /* We want receive timestamps. */ + sock_enable_timestamps(usk); + break; + + default: + BUG(); + } + + _leave(" = 0"); + return 0; +} + +/* + * Look up or create a new local endpoint using the specified local address. + */ +struct rxrpc_local *rxrpc_lookup_local(struct net *net, + const struct sockaddr_rxrpc *srx) +{ + struct rxrpc_local *local; + struct rxrpc_net *rxnet = rxrpc_net(net); + struct hlist_node *cursor; + const char *age; + long diff; + int ret; + + _enter("{%d,%d,%pISp}", + srx->transport_type, srx->transport.family, &srx->transport); + + mutex_lock(&rxnet->local_mutex); + + hlist_for_each(cursor, &rxnet->local_endpoints) { + local = hlist_entry(cursor, struct rxrpc_local, link); + + diff = rxrpc_local_cmp_key(local, srx); + if (diff != 0) + continue; + + /* 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 want to 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_use_local(local)) + break; + + age = "old"; + goto found; + } + + local = rxrpc_alloc_local(rxnet, srx); + if (!local) + goto nomem; + + ret = rxrpc_open_socket(local, net); + if (ret < 0) + goto sock_error; + + if (cursor) { + hlist_replace_rcu(cursor, &local->link); + cursor->pprev = NULL; + } else { + hlist_add_head_rcu(&local->link, &rxnet->local_endpoints); + } + age = "new"; + +found: + mutex_unlock(&rxnet->local_mutex); + + _net("LOCAL %s %d {%pISp}", + age, local->debug_id, &local->srx.transport); + + _leave(" = %p", local); + return local; + +nomem: + ret = -ENOMEM; +sock_error: + mutex_unlock(&rxnet->local_mutex); + if (local) + call_rcu(&local->rcu, rxrpc_local_rcu); + _leave(" = %d", ret); + return ERR_PTR(ret); + +addr_in_use: + mutex_unlock(&rxnet->local_mutex); + _leave(" = -EADDRINUSE"); + return ERR_PTR(-EADDRINUSE); +} + +/* + * Get a ref on a local endpoint. + */ +struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local) +{ + const void *here = __builtin_return_address(0); + int r; + + __refcount_inc(&local->ref, &r); + trace_rxrpc_local(local->debug_id, rxrpc_local_got, r + 1, here); + return local; +} + +/* + * Get a ref on a local endpoint unless its usage has already reached 0. + */ +struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local) +{ + const void *here = __builtin_return_address(0); + int r; + + if (local) { + if (__refcount_inc_not_zero(&local->ref, &r)) + trace_rxrpc_local(local->debug_id, rxrpc_local_got, + r + 1, here); + else + local = NULL; + } + return local; +} + +/* + * Queue a local endpoint and pass the caller's reference to the work item. + */ +void rxrpc_queue_local(struct rxrpc_local *local) +{ + const void *here = __builtin_return_address(0); + unsigned int debug_id = local->debug_id; + int r = refcount_read(&local->ref); + + if (rxrpc_queue_work(&local->processor)) + trace_rxrpc_local(debug_id, rxrpc_local_queued, r + 1, here); + else + rxrpc_put_local(local); +} + +/* + * Drop a ref on a local endpoint. + */ +void rxrpc_put_local(struct rxrpc_local *local) +{ + const void *here = __builtin_return_address(0); + unsigned int debug_id; + bool dead; + int r; + + if (local) { + debug_id = local->debug_id; + + dead = __refcount_dec_and_test(&local->ref, &r); + trace_rxrpc_local(debug_id, rxrpc_local_put, r, here); + + if (dead) + call_rcu(&local->rcu, rxrpc_local_rcu); + } +} + +/* + * Start using a local endpoint. + */ +struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local) +{ + local = rxrpc_get_local_maybe(local); + if (!local) + return NULL; + + if (!__rxrpc_use_local(local)) { + rxrpc_put_local(local); + return NULL; + } + + return local; +} + +/* + * Cease using a local endpoint. Once the number of active users reaches 0, we + * start the closure of the transport in the work processor. + */ +void rxrpc_unuse_local(struct rxrpc_local *local) +{ + if (local) { + if (__rxrpc_unuse_local(local)) { + rxrpc_get_local(local); + rxrpc_queue_local(local); + } + } +} + +/* + * 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; + struct rxrpc_net *rxnet = local->rxnet; + + _enter("%d", local->debug_id); + + local->dead = true; + + mutex_lock(&rxnet->local_mutex); + hlist_del_init_rcu(&local->link); + mutex_unlock(&rxnet->local_mutex); + + rxrpc_clean_up_local_conns(local); + rxrpc_service_connection_reaper(&rxnet->service_conn_reaper); + ASSERT(!local->service); + + 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->reject_queue); + rxrpc_purge_queue(&local->event_queue); +} + +/* + * Process events on an endpoint. The work item carries a ref which + * we must release. + */ +static void rxrpc_local_processor(struct work_struct *work) +{ + struct rxrpc_local *local = + container_of(work, struct rxrpc_local, processor); + bool again; + + if (local->dead) + return; + + trace_rxrpc_local(local->debug_id, rxrpc_local_processing, + refcount_read(&local->ref), NULL); + + do { + again = false; + if (!__rxrpc_use_local(local)) { + rxrpc_local_destroyer(local); + break; + } + + 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; + } + + __rxrpc_unuse_local(local); + } while (again); + + rxrpc_put_local(local); +} + +/* + * 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 rxrpc_destroy_all_locals(struct rxrpc_net *rxnet) +{ + struct rxrpc_local *local; + + _enter(""); + + flush_workqueue(rxrpc_workqueue); + + if (!hlist_empty(&rxnet->local_endpoints)) { + mutex_lock(&rxnet->local_mutex); + hlist_for_each_entry(local, &rxnet->local_endpoints, link) { + pr_err("AF_RXRPC: Leaked local %p {%d}\n", + local, refcount_read(&local->ref)); + } + mutex_unlock(&rxnet->local_mutex); + BUG(); + } +} |