/* 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 <linux/slab.h> #include <net/sock.h> #include <net/af_rxrpc.h> #include <net/ip.h> #include <net/route.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); /* * assess the MTU size for the network interface through which this peer is * reached */ static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer) { struct rtable *rt; struct flowi4 fl4; peer->if_mtu = 1500; rt = ip_route_output_ports(&init_net, &fl4, NULL, peer->srx.transport.sin.sin_addr.s_addr, 0, htons(7000), htons(7001), IPPROTO_UDP, 0, 0); if (IS_ERR(rt)) { _leave(" [route err %ld]", PTR_ERR(rt)); return; } peer->if_mtu = dst_mtu(&rt->dst); dst_release(&rt->dst); _leave(" [if_mtu %u]", peer->if_mtu); } /* * 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)); rxrpc_assess_MTU_size(peer); peer->mtu = peer->if_mtu; 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,%pI4+%hu}", srx->transport_type, srx->transport_len, &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; usage = atomic_read(&peer->usage); list_add_tail(&peer->link, &rxrpc_peers); write_unlock_bh(&rxrpc_peer_lock); new = "new"; success: _net("PEER %s %d {%d,%u,%pI4+%hu}", new, peer->debug_id, peer->srx.transport_type, peer->srx.transport.family, &peer->srx.transport.sin.sin_addr, ntohs(peer->srx.transport.sin.sin_port)); _leave(" = %p {u=%d}", 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"); 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; } rxrpc_queue_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(""); }