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 = sock_dequeue_err_skb(sk);
 41	if (!skb) {
 42		_leave("UDP socket errqueue empty");
 43		return;
 44	}
 45	serr = SKB_EXT_ERR(skb);
 46	if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
 47		_leave("UDP empty message");
 48		kfree_skb(skb);
 49		return;
 50	}
 51
 52	rxrpc_new_skb(skb);
 53
 54	addr = *(__be32 *)(skb_network_header(skb) + serr->addr_offset);
 55	port = serr->port;
 56
 57	_net("Rx UDP Error from %pI4:%hu", &addr, ntohs(port));
 58	_debug("Msg l:%d d:%d", skb->len, skb->data_len);
 59
 60	peer = rxrpc_find_peer(local, addr, port);
 61	if (IS_ERR(peer)) {
 62		rxrpc_free_skb(skb);
 63		_leave(" [no peer]");
 64		return;
 65	}
 66
 67	trans = rxrpc_find_transport(local, peer);
 68	if (!trans) {
 69		rxrpc_put_peer(peer);
 70		rxrpc_free_skb(skb);
 71		_leave(" [no trans]");
 72		return;
 73	}
 74
 75	if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
 76	    serr->ee.ee_type == ICMP_DEST_UNREACH &&
 77	    serr->ee.ee_code == ICMP_FRAG_NEEDED
 78	    ) {
 79		u32 mtu = serr->ee.ee_info;
 80
 81		_net("Rx Received ICMP Fragmentation Needed (%d)", mtu);
 82
 83		/* wind down the local interface MTU */
 84		if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
 85			peer->if_mtu = mtu;
 86			_net("I/F MTU %u", mtu);
 87		}
 88
 89		if (mtu == 0) {
 90			/* they didn't give us a size, estimate one */
 91			mtu = peer->if_mtu;
 92			if (mtu > 1500) {
 93				mtu >>= 1;
 94				if (mtu < 1500)
 95					mtu = 1500;
 96			} else {
 97				mtu -= 100;
 98				if (mtu < peer->hdrsize)
 99					mtu = peer->hdrsize + 4;
100			}
101		}
102
103		if (mtu < peer->mtu) {
104			spin_lock_bh(&peer->lock);
105			peer->mtu = mtu;
106			peer->maxdata = peer->mtu - peer->hdrsize;
107			spin_unlock_bh(&peer->lock);
108			_net("Net MTU %u (maxdata %u)",
109			     peer->mtu, peer->maxdata);
110		}
111	}
112
113	rxrpc_put_peer(peer);
114
115	/* pass the transport ref to error_handler to release */
116	skb_queue_tail(&trans->error_queue, skb);
117	rxrpc_queue_work(&trans->error_handler);
118	_leave("");
119}
120
121/*
122 * deal with UDP error messages
123 */
124void rxrpc_UDP_error_handler(struct work_struct *work)
125{
126	struct sock_extended_err *ee;
127	struct sock_exterr_skb *serr;
128	struct rxrpc_transport *trans =
129		container_of(work, struct rxrpc_transport, error_handler);
130	struct sk_buff *skb;
131	int err;
132
133	_enter("");
134
135	skb = skb_dequeue(&trans->error_queue);
136	if (!skb)
137		return;
138
139	serr = SKB_EXT_ERR(skb);
140	ee = &serr->ee;
141
142	_net("Rx Error o=%d t=%d c=%d e=%d",
143	     ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
144
145	err = ee->ee_errno;
146
147	switch (ee->ee_origin) {
148	case SO_EE_ORIGIN_ICMP:
149		switch (ee->ee_type) {
150		case ICMP_DEST_UNREACH:
151			switch (ee->ee_code) {
152			case ICMP_NET_UNREACH:
153				_net("Rx Received ICMP Network Unreachable");
154				break;
155			case ICMP_HOST_UNREACH:
156				_net("Rx Received ICMP Host Unreachable");
157				break;
158			case ICMP_PORT_UNREACH:
159				_net("Rx Received ICMP Port Unreachable");
160				break;
161			case ICMP_NET_UNKNOWN:
162				_net("Rx Received ICMP Unknown Network");
163				break;
164			case ICMP_HOST_UNKNOWN:
165				_net("Rx Received ICMP Unknown Host");
166				break;
167			default:
168				_net("Rx Received ICMP DestUnreach code=%u",
169				     ee->ee_code);
170				break;
171			}
172			break;
173
174		case ICMP_TIME_EXCEEDED:
175			_net("Rx Received ICMP TTL Exceeded");
176			break;
177
178		default:
179			_proto("Rx Received ICMP error { type=%u code=%u }",
180			       ee->ee_type, ee->ee_code);
181			break;
182		}
183		break;
184
185	case SO_EE_ORIGIN_LOCAL:
186		_proto("Rx Received local error { error=%d }",
187		       ee->ee_errno);
188		break;
189
190	case SO_EE_ORIGIN_NONE:
191	case SO_EE_ORIGIN_ICMP6:
192	default:
193		_proto("Rx Received error report { orig=%u }",
194		       ee->ee_origin);
195		break;
196	}
197
198	/* terminate all the affected calls if there's an unrecoverable
199	 * error */
200	if (err) {
201		struct rxrpc_call *call, *_n;
202
203		_debug("ISSUE ERROR %d", err);
204
205		spin_lock_bh(&trans->peer->lock);
206		trans->peer->net_error = err;
207
208		list_for_each_entry_safe(call, _n, &trans->peer->error_targets,
209					 error_link) {
210			write_lock(&call->state_lock);
211			if (call->state != RXRPC_CALL_COMPLETE &&
212			    call->state < RXRPC_CALL_NETWORK_ERROR) {
213				call->state = RXRPC_CALL_NETWORK_ERROR;
214				set_bit(RXRPC_CALL_EV_RCVD_ERROR, &call->events);
215				rxrpc_queue_call(call);
216			}
217			write_unlock(&call->state_lock);
218			list_del_init(&call->error_link);
219		}
220
221		spin_unlock_bh(&trans->peer->lock);
222	}
223
224	if (!skb_queue_empty(&trans->error_queue))
225		rxrpc_queue_work(&trans->error_handler);
226
227	rxrpc_free_skb(skb);
228	rxrpc_put_transport(trans);
229	_leave("");
230}