302 lines
7.1 KiB
C
302 lines
7.1 KiB
C
/* RxRPC remote transport endpoint management
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/net.h>
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#include <linux/skbuff.h>
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#include <linux/udp.h>
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#include <linux/in.h>
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#include <linux/in6.h>
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#include <linux/icmp.h>
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#include <linux/slab.h>
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#include <net/sock.h>
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#include <net/af_rxrpc.h>
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#include <net/ip.h>
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#include <net/route.h>
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#include "ar-internal.h"
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static LIST_HEAD(rxrpc_peers);
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static DEFINE_RWLOCK(rxrpc_peer_lock);
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static DECLARE_WAIT_QUEUE_HEAD(rxrpc_peer_wq);
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static void rxrpc_destroy_peer(struct work_struct *work);
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/*
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* assess the MTU size for the network interface through which this peer is
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* reached
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*/
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static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer)
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{
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struct rtable *rt;
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peer->if_mtu = 1500;
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rt = ip_route_output_ports(&init_net, NULL,
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peer->srx.transport.sin.sin_addr.s_addr, 0,
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htons(7000), htons(7001),
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IPPROTO_UDP, 0, 0);
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if (IS_ERR(rt)) {
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_leave(" [route err %ld]", PTR_ERR(rt));
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return;
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}
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peer->if_mtu = dst_mtu(&rt->dst);
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dst_release(&rt->dst);
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_leave(" [if_mtu %u]", peer->if_mtu);
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}
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/*
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* allocate a new peer
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*/
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static struct rxrpc_peer *rxrpc_alloc_peer(struct sockaddr_rxrpc *srx,
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gfp_t gfp)
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{
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struct rxrpc_peer *peer;
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_enter("");
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peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
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if (peer) {
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INIT_WORK(&peer->destroyer, &rxrpc_destroy_peer);
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INIT_LIST_HEAD(&peer->link);
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INIT_LIST_HEAD(&peer->error_targets);
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spin_lock_init(&peer->lock);
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atomic_set(&peer->usage, 1);
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peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
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memcpy(&peer->srx, srx, sizeof(*srx));
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rxrpc_assess_MTU_size(peer);
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peer->mtu = peer->if_mtu;
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if (srx->transport.family == AF_INET) {
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peer->hdrsize = sizeof(struct iphdr);
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switch (srx->transport_type) {
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case SOCK_DGRAM:
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peer->hdrsize += sizeof(struct udphdr);
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break;
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default:
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BUG();
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break;
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}
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} else {
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BUG();
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}
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peer->hdrsize += sizeof(struct rxrpc_header);
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peer->maxdata = peer->mtu - peer->hdrsize;
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}
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_leave(" = %p", peer);
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return peer;
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}
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/*
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* obtain a remote transport endpoint for the specified address
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*/
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struct rxrpc_peer *rxrpc_get_peer(struct sockaddr_rxrpc *srx, gfp_t gfp)
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{
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struct rxrpc_peer *peer, *candidate;
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const char *new = "old";
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int usage;
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_enter("{%d,%d,%pI4+%hu}",
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srx->transport_type,
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srx->transport_len,
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&srx->transport.sin.sin_addr,
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ntohs(srx->transport.sin.sin_port));
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/* search the peer list first */
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read_lock_bh(&rxrpc_peer_lock);
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list_for_each_entry(peer, &rxrpc_peers, link) {
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_debug("check PEER %d { u=%d t=%d l=%d }",
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peer->debug_id,
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atomic_read(&peer->usage),
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peer->srx.transport_type,
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peer->srx.transport_len);
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if (atomic_read(&peer->usage) > 0 &&
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peer->srx.transport_type == srx->transport_type &&
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peer->srx.transport_len == srx->transport_len &&
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memcmp(&peer->srx.transport,
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&srx->transport,
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srx->transport_len) == 0)
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goto found_extant_peer;
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}
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read_unlock_bh(&rxrpc_peer_lock);
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/* not yet present - create a candidate for a new record and then
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* redo the search */
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candidate = rxrpc_alloc_peer(srx, gfp);
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if (!candidate) {
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_leave(" = -ENOMEM");
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return ERR_PTR(-ENOMEM);
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}
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write_lock_bh(&rxrpc_peer_lock);
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list_for_each_entry(peer, &rxrpc_peers, link) {
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if (atomic_read(&peer->usage) > 0 &&
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peer->srx.transport_type == srx->transport_type &&
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peer->srx.transport_len == srx->transport_len &&
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memcmp(&peer->srx.transport,
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&srx->transport,
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srx->transport_len) == 0)
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goto found_extant_second;
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}
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/* we can now add the new candidate to the list */
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peer = candidate;
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candidate = NULL;
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list_add_tail(&peer->link, &rxrpc_peers);
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write_unlock_bh(&rxrpc_peer_lock);
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new = "new";
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success:
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_net("PEER %s %d {%d,%u,%pI4+%hu}",
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new,
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peer->debug_id,
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peer->srx.transport_type,
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peer->srx.transport.family,
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&peer->srx.transport.sin.sin_addr,
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ntohs(peer->srx.transport.sin.sin_port));
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_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
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return peer;
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/* we found the peer in the list immediately */
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found_extant_peer:
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usage = atomic_inc_return(&peer->usage);
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read_unlock_bh(&rxrpc_peer_lock);
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goto success;
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/* we found the peer on the second time through the list */
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found_extant_second:
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usage = atomic_inc_return(&peer->usage);
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write_unlock_bh(&rxrpc_peer_lock);
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kfree(candidate);
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goto success;
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}
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/*
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* find the peer associated with a packet
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*/
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struct rxrpc_peer *rxrpc_find_peer(struct rxrpc_local *local,
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__be32 addr, __be16 port)
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{
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struct rxrpc_peer *peer;
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_enter("");
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/* search the peer list */
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read_lock_bh(&rxrpc_peer_lock);
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if (local->srx.transport.family == AF_INET &&
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local->srx.transport_type == SOCK_DGRAM
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) {
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list_for_each_entry(peer, &rxrpc_peers, link) {
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if (atomic_read(&peer->usage) > 0 &&
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peer->srx.transport_type == SOCK_DGRAM &&
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peer->srx.transport.family == AF_INET &&
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peer->srx.transport.sin.sin_port == port &&
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peer->srx.transport.sin.sin_addr.s_addr == addr)
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goto found_UDP_peer;
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}
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goto new_UDP_peer;
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}
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read_unlock_bh(&rxrpc_peer_lock);
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_leave(" = -EAFNOSUPPORT");
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return ERR_PTR(-EAFNOSUPPORT);
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found_UDP_peer:
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_net("Rx UDP DGRAM from peer %d", peer->debug_id);
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atomic_inc(&peer->usage);
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read_unlock_bh(&rxrpc_peer_lock);
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_leave(" = %p", peer);
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return peer;
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new_UDP_peer:
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_net("Rx UDP DGRAM from NEW peer %d", peer->debug_id);
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read_unlock_bh(&rxrpc_peer_lock);
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_leave(" = -EBUSY [new]");
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return ERR_PTR(-EBUSY);
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}
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/*
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* release a remote transport endpoint
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*/
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void rxrpc_put_peer(struct rxrpc_peer *peer)
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{
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_enter("%p{u=%d}", peer, atomic_read(&peer->usage));
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ASSERTCMP(atomic_read(&peer->usage), >, 0);
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if (likely(!atomic_dec_and_test(&peer->usage))) {
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_leave(" [in use]");
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return;
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}
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rxrpc_queue_work(&peer->destroyer);
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_leave("");
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}
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/*
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* destroy a remote transport endpoint
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*/
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static void rxrpc_destroy_peer(struct work_struct *work)
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{
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struct rxrpc_peer *peer =
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container_of(work, struct rxrpc_peer, destroyer);
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_enter("%p{%d}", peer, atomic_read(&peer->usage));
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write_lock_bh(&rxrpc_peer_lock);
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list_del(&peer->link);
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write_unlock_bh(&rxrpc_peer_lock);
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_net("DESTROY PEER %d", peer->debug_id);
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kfree(peer);
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if (list_empty(&rxrpc_peers))
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wake_up_all(&rxrpc_peer_wq);
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_leave("");
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}
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/*
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* preemptively destroy all the peer records from a transport endpoint rather
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* than waiting for them to time out
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*/
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void __exit rxrpc_destroy_all_peers(void)
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{
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DECLARE_WAITQUEUE(myself,current);
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_enter("");
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/* we simply have to wait for them to go away */
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if (!list_empty(&rxrpc_peers)) {
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set_current_state(TASK_UNINTERRUPTIBLE);
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add_wait_queue(&rxrpc_peer_wq, &myself);
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while (!list_empty(&rxrpc_peers)) {
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schedule();
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set_current_state(TASK_UNINTERRUPTIBLE);
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}
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remove_wait_queue(&rxrpc_peer_wq, &myself);
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set_current_state(TASK_RUNNING);
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}
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_leave("");
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}
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