1/* Error message handling (ICMP)
  2 *
  3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
  4 * Written by David Howells (dhowells@redhat.com)
  5 *
  6 * This program is free software; you can redistribute it and/or
  7 * modify it under the terms of the GNU General Public License
  8 * as published by the Free Software Foundation; either version
  9 * 2 of the License, or (at your option) any later version.
 10 */
 11
 12#include <linux/module.h>
 13#include <linux/net.h>
 14#include <linux/skbuff.h>
 15#include <linux/errqueue.h>
 16#include <linux/udp.h>
 17#include <linux/in.h>
 18#include <linux/in6.h>
 19#include <linux/icmp.h>
 20#include <net/sock.h>
 21#include <net/af_rxrpc.h>
 22#include <net/ip.h>
 23#include "ar-internal.h"
 24
 25/*
 26 * handle an error received on the local endpoint
 27 */
 28void rxrpc_UDP_error_report(struct sock *sk)
 29{
 30	struct sock_exterr_skb *serr;
 31	struct rxrpc_transport *trans;
 32	struct rxrpc_local *local = sk->sk_user_data;
 33	struct rxrpc_peer *peer;
 34	struct sk_buff *skb;
 35	__be32 addr;
 36	__be16 port;
 37
 38	_enter("%p{%d}", sk, local->debug_id);
 39
 40	skb = skb_dequeue(&sk->sk_error_queue);
 41	if (!skb) {
 42		_leave("UDP socket errqueue empty");
 43		return;
 44	}
 45
 46	rxrpc_new_skb(skb);
 47
 48	serr = SKB_EXT_ERR(skb);
 49	addr = *(__be32 *)(skb_network_header(skb) + serr->addr_offset);
 50	port = serr->port;
 51
 52	_net("Rx UDP Error from %pI4:%hu", &addr, ntohs(port));
 53	_debug("Msg l:%d d:%d", skb->len, skb->data_len);
 54
 55	peer = rxrpc_find_peer(local, addr, port);
 56	if (IS_ERR(peer)) {
 57		rxrpc_free_skb(skb);
 58		_leave(" [no peer]");
 59		return;
 60	}
 61
 62	trans = rxrpc_find_transport(local, peer);
 63	if (!trans) {
 64		rxrpc_put_peer(peer);
 65		rxrpc_free_skb(skb);
 66		_leave(" [no trans]");
 67		return;
 68	}
 69
 70	if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
 71	    serr->ee.ee_type == ICMP_DEST_UNREACH &&
 72	    serr->ee.ee_code == ICMP_FRAG_NEEDED
 73	    ) {
 74		u32 mtu = serr->ee.ee_info;
 75
 76		_net("Rx Received ICMP Fragmentation Needed (%d)", mtu);
 77
 78		/* wind down the local interface MTU */
 79		if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
 80			peer->if_mtu = mtu;
 81			_net("I/F MTU %u", mtu);
 82		}
 83
 84		/* ip_rt_frag_needed() may have eaten the info */
 85		if (mtu == 0)
 86			mtu = ntohs(icmp_hdr(skb)->un.frag.mtu);
 87
 88		if (mtu == 0) {
 89			/* they didn't give us a size, estimate one */
 90			if (mtu > 1500) {
 91				mtu >>= 1;
 92				if (mtu < 1500)
 93					mtu = 1500;
 94			} else {
 95				mtu -= 100;
 96				if (mtu < peer->hdrsize)
 97					mtu = peer->hdrsize + 4;
 98			}
 99		}
100
101		if (mtu < peer->mtu) {
102			spin_lock_bh(&peer->lock);
103			peer->mtu = mtu;
104			peer->maxdata = peer->mtu - peer->hdrsize;
105			spin_unlock_bh(&peer->lock);
106			_net("Net MTU %u (maxdata %u)",
107			     peer->mtu, peer->maxdata);
108		}
109	}
110
111	rxrpc_put_peer(peer);
112
113	/* pass the transport ref to error_handler to release */
114	skb_queue_tail(&trans->error_queue, skb);
115	rxrpc_queue_work(&trans->error_handler);
116
117	/* reset and regenerate socket error */
118	spin_lock_bh(&sk->sk_error_queue.lock);
119	sk->sk_err = 0;
120	skb = skb_peek(&sk->sk_error_queue);
121	if (skb) {
122		sk->sk_err = SKB_EXT_ERR(skb)->ee.ee_errno;
123		spin_unlock_bh(&sk->sk_error_queue.lock);
124		sk->sk_error_report(sk);
125	} else {
126		spin_unlock_bh(&sk->sk_error_queue.lock);
127	}
128
129	_leave("");
130}
131
132/*
133 * deal with UDP error messages
134 */
135void rxrpc_UDP_error_handler(struct work_struct *work)
136{
137	struct sock_extended_err *ee;
138	struct sock_exterr_skb *serr;
139	struct rxrpc_transport *trans =
140		container_of(work, struct rxrpc_transport, error_handler);
141	struct sk_buff *skb;
142	int err;
143
144	_enter("");
145
146	skb = skb_dequeue(&trans->error_queue);
147	if (!skb)
148		return;
149
150	serr = SKB_EXT_ERR(skb);
151	ee = &serr->ee;
152
153	_net("Rx Error o=%d t=%d c=%d e=%d",
154	     ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
155
156	err = ee->ee_errno;
157
158	switch (ee->ee_origin) {
159	case SO_EE_ORIGIN_ICMP:
160		switch (ee->ee_type) {
161		case ICMP_DEST_UNREACH:
162			switch (ee->ee_code) {
163			case ICMP_NET_UNREACH:
164				_net("Rx Received ICMP Network Unreachable");
165				err = ENETUNREACH;
166				break;
167			case ICMP_HOST_UNREACH:
168				_net("Rx Received ICMP Host Unreachable");
169				err = EHOSTUNREACH;
170				break;
171			case ICMP_PORT_UNREACH:
172				_net("Rx Received ICMP Port Unreachable");
173				err = ECONNREFUSED;
174				break;
175			case ICMP_FRAG_NEEDED:
176				_net("Rx Received ICMP Fragmentation Needed (%d)",
177				     ee->ee_info);
178				err = 0; /* dealt with elsewhere */
179				break;
180			case ICMP_NET_UNKNOWN:
181				_net("Rx Received ICMP Unknown Network");
182				err = ENETUNREACH;
183				break;
184			case ICMP_HOST_UNKNOWN:
185				_net("Rx Received ICMP Unknown Host");
186				err = EHOSTUNREACH;
187				break;
188			default:
189				_net("Rx Received ICMP DestUnreach code=%u",
190				     ee->ee_code);
191				break;
192			}
193			break;
194
195		case ICMP_TIME_EXCEEDED:
196			_net("Rx Received ICMP TTL Exceeded");
197			break;
198
199		default:
200			_proto("Rx Received ICMP error { type=%u code=%u }",
201			       ee->ee_type, ee->ee_code);
202			break;
203		}
204		break;
205
206	case SO_EE_ORIGIN_LOCAL:
207		_proto("Rx Received local error { error=%d }",
208		       ee->ee_errno);
209		break;
210
211	case SO_EE_ORIGIN_NONE:
212	case SO_EE_ORIGIN_ICMP6:
213	default:
214		_proto("Rx Received error report { orig=%u }",
215		       ee->ee_origin);
216		break;
217	}
218
219	/* terminate all the affected calls if there's an unrecoverable
220	 * error */
221	if (err) {
222		struct rxrpc_call *call, *_n;
223
224		_debug("ISSUE ERROR %d", err);
225
226		spin_lock_bh(&trans->peer->lock);
227		trans->peer->net_error = err;
228
229		list_for_each_entry_safe(call, _n, &trans->peer->error_targets,
230					 error_link) {
231			write_lock(&call->state_lock);
232			if (call->state != RXRPC_CALL_COMPLETE &&
233			    call->state < RXRPC_CALL_NETWORK_ERROR) {
234				call->state = RXRPC_CALL_NETWORK_ERROR;
235				set_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
236				rxrpc_queue_call(call);
237			}
238			write_unlock(&call->state_lock);
239			list_del_init(&call->error_link);
240		}
241
242		spin_unlock_bh(&trans->peer->lock);
243	}
244
245	if (!skb_queue_empty(&trans->error_queue))
246		rxrpc_queue_work(&trans->error_handler);
247
248	rxrpc_free_skb(skb);
249	rxrpc_put_transport(trans);
250	_leave("");
251}