![David Howells](/assets/img/avatar_default.png)
Use the peer record to distribute network errors rather than the transport object (which I want to get rid of). An error from a particular peer terminates all calls on that peer. For future consideration: (1) For ICMP-induced errors it might be worth trying to extract the RxRPC header from the offending packet, if one is returned attached to the ICMP packet, to better direct the error. This may be overkill, though, since an ICMP packet would be expected to be relating to the destination port, machine or network. RxRPC ABORT and BUSY packets give notice at RxRPC level. (2) To also abort connection-level communications (such as CHALLENGE packets) where indicted by an error - but that requires some revamping of the connection event handling first. Signed-off-by: David Howells <dhowells@redhat.com>
282 lines
6.4 KiB
C
282 lines
6.4 KiB
C
/* Peer event handling, typically ICMP messages.
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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/errqueue.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 <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 "ar-internal.h"
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static void rxrpc_store_error(struct rxrpc_peer *, struct sock_exterr_skb *);
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/*
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* Find the peer associated with an ICMP packet.
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*/
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static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
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const struct sk_buff *skb)
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{
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struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
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struct sockaddr_rxrpc srx;
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_enter("");
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memset(&srx, 0, sizeof(srx));
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srx.transport_type = local->srx.transport_type;
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srx.transport.family = local->srx.transport.family;
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/* Can we see an ICMP4 packet on an ICMP6 listening socket? and vice
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* versa?
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*/
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switch (srx.transport.family) {
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case AF_INET:
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srx.transport.sin.sin_port = serr->port;
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srx.transport_len = sizeof(struct sockaddr_in);
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switch (serr->ee.ee_origin) {
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case SO_EE_ORIGIN_ICMP:
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_net("Rx ICMP");
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memcpy(&srx.transport.sin.sin_addr,
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skb_network_header(skb) + serr->addr_offset,
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sizeof(struct in_addr));
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break;
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case SO_EE_ORIGIN_ICMP6:
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_net("Rx ICMP6 on v4 sock");
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memcpy(&srx.transport.sin.sin_addr,
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skb_network_header(skb) + serr->addr_offset + 12,
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sizeof(struct in_addr));
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break;
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default:
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memcpy(&srx.transport.sin.sin_addr, &ip_hdr(skb)->saddr,
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sizeof(struct in_addr));
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break;
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}
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break;
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default:
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BUG();
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}
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return rxrpc_lookup_peer_rcu(local, &srx);
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}
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/*
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* Handle an MTU/fragmentation problem.
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*/
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static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr)
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{
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u32 mtu = serr->ee.ee_info;
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_net("Rx ICMP Fragmentation Needed (%d)", mtu);
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/* wind down the local interface MTU */
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if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
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peer->if_mtu = mtu;
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_net("I/F MTU %u", mtu);
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}
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if (mtu == 0) {
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/* they didn't give us a size, estimate one */
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mtu = peer->if_mtu;
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if (mtu > 1500) {
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mtu >>= 1;
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if (mtu < 1500)
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mtu = 1500;
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} else {
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mtu -= 100;
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if (mtu < peer->hdrsize)
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mtu = peer->hdrsize + 4;
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}
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}
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if (mtu < peer->mtu) {
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spin_lock_bh(&peer->lock);
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peer->mtu = mtu;
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peer->maxdata = peer->mtu - peer->hdrsize;
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spin_unlock_bh(&peer->lock);
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_net("Net MTU %u (maxdata %u)",
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peer->mtu, peer->maxdata);
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}
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}
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/*
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* Handle an error received on the local endpoint.
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*/
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void rxrpc_error_report(struct sock *sk)
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{
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struct sock_exterr_skb *serr;
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struct rxrpc_local *local = sk->sk_user_data;
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struct rxrpc_peer *peer;
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struct sk_buff *skb;
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_enter("%p{%d}", sk, local->debug_id);
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skb = sock_dequeue_err_skb(sk);
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if (!skb) {
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_leave("UDP socket errqueue empty");
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return;
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}
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serr = SKB_EXT_ERR(skb);
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if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
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_leave("UDP empty message");
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kfree_skb(skb);
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return;
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}
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rxrpc_new_skb(skb);
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rcu_read_lock();
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peer = rxrpc_lookup_peer_icmp_rcu(local, skb);
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if (peer && !rxrpc_get_peer_maybe(peer))
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peer = NULL;
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if (!peer) {
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rcu_read_unlock();
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rxrpc_free_skb(skb);
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_leave(" [no peer]");
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return;
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}
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if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
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serr->ee.ee_type == ICMP_DEST_UNREACH &&
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serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
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rxrpc_adjust_mtu(peer, serr);
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rcu_read_unlock();
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rxrpc_free_skb(skb);
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rxrpc_put_peer(peer);
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_leave(" [MTU update]");
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return;
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}
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rxrpc_store_error(peer, serr);
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rcu_read_unlock();
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rxrpc_free_skb(skb);
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/* The ref we obtained is passed off to the work item */
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rxrpc_queue_work(&peer->error_distributor);
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_leave("");
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}
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/*
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* Map an error report to error codes on the peer record.
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*/
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static void rxrpc_store_error(struct rxrpc_peer *peer,
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struct sock_exterr_skb *serr)
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{
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struct sock_extended_err *ee;
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int err;
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_enter("");
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ee = &serr->ee;
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_net("Rx Error o=%d t=%d c=%d e=%d",
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ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
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err = ee->ee_errno;
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switch (ee->ee_origin) {
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case SO_EE_ORIGIN_ICMP:
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switch (ee->ee_type) {
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case ICMP_DEST_UNREACH:
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switch (ee->ee_code) {
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case ICMP_NET_UNREACH:
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_net("Rx Received ICMP Network Unreachable");
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break;
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case ICMP_HOST_UNREACH:
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_net("Rx Received ICMP Host Unreachable");
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break;
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case ICMP_PORT_UNREACH:
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_net("Rx Received ICMP Port Unreachable");
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break;
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case ICMP_NET_UNKNOWN:
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_net("Rx Received ICMP Unknown Network");
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break;
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case ICMP_HOST_UNKNOWN:
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_net("Rx Received ICMP Unknown Host");
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break;
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default:
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_net("Rx Received ICMP DestUnreach code=%u",
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ee->ee_code);
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break;
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}
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break;
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case ICMP_TIME_EXCEEDED:
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_net("Rx Received ICMP TTL Exceeded");
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break;
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default:
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_proto("Rx Received ICMP error { type=%u code=%u }",
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ee->ee_type, ee->ee_code);
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break;
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}
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break;
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case SO_EE_ORIGIN_NONE:
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case SO_EE_ORIGIN_LOCAL:
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_proto("Rx Received local error { error=%d }", err);
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err += RXRPC_LOCAL_ERROR_OFFSET;
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break;
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case SO_EE_ORIGIN_ICMP6:
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default:
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_proto("Rx Received error report { orig=%u }", ee->ee_origin);
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break;
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}
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peer->error_report = err;
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}
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/*
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* Distribute an error that occurred on a peer
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*/
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void rxrpc_peer_error_distributor(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, error_distributor);
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struct rxrpc_call *call;
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int error_report;
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_enter("");
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error_report = READ_ONCE(peer->error_report);
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_debug("ISSUE ERROR %d", error_report);
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spin_lock_bh(&peer->lock);
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while (!hlist_empty(&peer->error_targets)) {
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call = hlist_entry(peer->error_targets.first,
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struct rxrpc_call, error_link);
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hlist_del_init(&call->error_link);
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write_lock(&call->state_lock);
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if (call->state != RXRPC_CALL_COMPLETE &&
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call->state < RXRPC_CALL_NETWORK_ERROR) {
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call->error_report = error_report;
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call->state = RXRPC_CALL_NETWORK_ERROR;
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set_bit(RXRPC_CALL_EV_RCVD_ERROR, &call->events);
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rxrpc_queue_call(call);
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}
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write_unlock(&call->state_lock);
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}
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spin_unlock_bh(&peer->lock);
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rxrpc_put_peer(peer);
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_leave("");
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}
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