diff options
Diffstat (limited to 'net/rxrpc/ar-peer.c')
| -rw-r--r-- | net/rxrpc/ar-peer.c | 273 |
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 0000000..69ac355 --- /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(""); +} |