net/rxrpc/peer_event.c - kernel/common - Git at Google

 /* Peer event handling, typically ICMP messages.
  *
  * 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/errqueue.h>
 #include <linux/udp.h>
 #include <linux/in.h>
 #include <linux/in6.h>
 #include <linux/icmp.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
 #include <net/ip.h>
 #include "ar-internal.h"

 static void rxrpc_store_error(struct rxrpc_peer *, struct sock_exterr_skb *);

 /*
  * Find the peer associated with an ICMP packet.
  */
 static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
 						     const struct sk_buff *skb)
 {
 	struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
 	struct sockaddr_rxrpc srx;

 	_enter("");

 	memset(&srx, 0, sizeof(srx));
 	srx.transport_type = local->srx.transport_type;
 	srx.transport_len = local->srx.transport_len;
 	srx.transport.family = local->srx.transport.family;

 	/* Can we see an ICMP4 packet on an ICMP6 listening socket?  and vice
 	 * versa?
 	 */
 	switch (srx.transport.family) {
 	case AF_INET:
 		srx.transport.sin.sin_port = serr->port;
 		switch (serr->ee.ee_origin) {
 		case SO_EE_ORIGIN_ICMP:
 			_net("Rx ICMP");
 			memcpy(&srx.transport.sin.sin_addr,
 			       skb_network_header(skb) + serr->addr_offset,
 			       sizeof(struct in_addr));
 			break;
 		case SO_EE_ORIGIN_ICMP6:
 			_net("Rx ICMP6 on v4 sock");
 			memcpy(&srx.transport.sin.sin_addr,
 			       skb_network_header(skb) + serr->addr_offset + 12,
 			       sizeof(struct in_addr));
 			break;
 		default:
 			memcpy(&srx.transport.sin.sin_addr, &ip_hdr(skb)->saddr,
 			       sizeof(struct in_addr));
 			break;
 		}
 		break;

 #ifdef CONFIG_AF_RXRPC_IPV6
 	case AF_INET6:
 		srx.transport.sin6.sin6_port = serr->port;
 		switch (serr->ee.ee_origin) {
 		case SO_EE_ORIGIN_ICMP6:
 			_net("Rx ICMP6");
 			memcpy(&srx.transport.sin6.sin6_addr,
 			       skb_network_header(skb) + serr->addr_offset,
 			       sizeof(struct in6_addr));
 			break;
 		case SO_EE_ORIGIN_ICMP:
 			_net("Rx ICMP on v6 sock");
 			srx.transport.sin6.sin6_addr.s6_addr32[0] = 0;
 			srx.transport.sin6.sin6_addr.s6_addr32[1] = 0;
 			srx.transport.sin6.sin6_addr.s6_addr32[2] = htonl(0xffff);
 			memcpy(srx.transport.sin6.sin6_addr.s6_addr + 12,
 			       skb_network_header(skb) + serr->addr_offset,
 			       sizeof(struct in_addr));
 			break;
 		default:
 			memcpy(&srx.transport.sin6.sin6_addr,
 			       &ipv6_hdr(skb)->saddr,
 			       sizeof(struct in6_addr));
 			break;
 		}
 		break;
 #endif

 	default:
 		BUG();
 	}

 	return rxrpc_lookup_peer_rcu(local, &srx);
 }

 /*
  * Handle an MTU/fragmentation problem.
  */
 static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr)
 {
 	u32 mtu = serr->ee.ee_info;

 	_net("Rx ICMP Fragmentation Needed (%d)", mtu);

 	/* wind down the local interface MTU */
 	if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
 		peer->if_mtu = mtu;
 		_net("I/F MTU %u", mtu);
 	}

 	if (mtu == 0) {
 		/* they didn't give us a size, estimate one */
 		mtu = peer->if_mtu;
 		if (mtu > 1500) {
 			mtu >>= 1;
 			if (mtu < 1500)
 				mtu = 1500;
 		} else {
 			mtu -= 100;
 			if (mtu < peer->hdrsize)
 				mtu = peer->hdrsize + 4;
 		}
 	}

 	if (mtu < peer->mtu) {
 		spin_lock_bh(&peer->lock);
 		peer->mtu = mtu;
 		peer->maxdata = peer->mtu - peer->hdrsize;
 		spin_unlock_bh(&peer->lock);
 		_net("Net MTU %u (maxdata %u)",
 		     peer->mtu, peer->maxdata);
 	}
 }

 /*
  * Handle an error received on the local endpoint.
  */
 void rxrpc_error_report(struct sock *sk)
 {
 	struct sock_exterr_skb *serr;
 	struct rxrpc_local *local = sk->sk_user_data;
 	struct rxrpc_peer *peer;
 	struct sk_buff *skb;

 	_enter("%p{%d}", sk, local->debug_id);

 	skb = sock_dequeue_err_skb(sk);
 	if (!skb) {
 		_leave("UDP socket errqueue empty");
 		return;
 	}
 	rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 	serr = SKB_EXT_ERR(skb);
 	if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
 		_leave("UDP empty message");
 		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 		return;
 	}

 	rcu_read_lock();
 	peer = rxrpc_lookup_peer_icmp_rcu(local, skb);
 	if (peer && !rxrpc_get_peer_maybe(peer))
 		peer = NULL;
 	if (!peer) {
 		rcu_read_unlock();
 		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 		_leave(" [no peer]");
 		return;
 	}

 	if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
 	     serr->ee.ee_type == ICMP_DEST_UNREACH &&
 	     serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
 		rxrpc_adjust_mtu(peer, serr);
 		rcu_read_unlock();
 		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 		rxrpc_put_peer(peer);
 		_leave(" [MTU update]");
 		return;
 	}

 	rxrpc_store_error(peer, serr);
 	rcu_read_unlock();
 	rxrpc_free_skb(skb, rxrpc_skb_rx_freed);

 	/* The ref we obtained is passed off to the work item */
 	rxrpc_queue_work(&peer->error_distributor);
 	_leave("");
 }

 /*
  * Map an error report to error codes on the peer record.
  */
 static void rxrpc_store_error(struct rxrpc_peer *peer,
 			      struct sock_exterr_skb *serr)
 {
 	struct sock_extended_err *ee;
 	int err;

 	_enter("");

 	ee = &serr->ee;

 	_net("Rx Error o=%d t=%d c=%d e=%d",
 	     ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);

 	err = ee->ee_errno;

 	switch (ee->ee_origin) {
 	case SO_EE_ORIGIN_ICMP:
 		switch (ee->ee_type) {
 		case ICMP_DEST_UNREACH:
 			switch (ee->ee_code) {
 			case ICMP_NET_UNREACH:
 				_net("Rx Received ICMP Network Unreachable");
 				break;
 			case ICMP_HOST_UNREACH:
 				_net("Rx Received ICMP Host Unreachable");
 				break;
 			case ICMP_PORT_UNREACH:
 				_net("Rx Received ICMP Port Unreachable");
 				break;
 			case ICMP_NET_UNKNOWN:
 				_net("Rx Received ICMP Unknown Network");
 				break;
 			case ICMP_HOST_UNKNOWN:
 				_net("Rx Received ICMP Unknown Host");
 				break;
 			default:
 				_net("Rx Received ICMP DestUnreach code=%u",
 				     ee->ee_code);
 				break;
 			}
 			break;

 		case ICMP_TIME_EXCEEDED:
 			_net("Rx Received ICMP TTL Exceeded");
 			break;

 		default:
 			_proto("Rx Received ICMP error { type=%u code=%u }",
 			       ee->ee_type, ee->ee_code);
 			break;
 		}
 		break;

 	case SO_EE_ORIGIN_NONE:
 	case SO_EE_ORIGIN_LOCAL:
 		_proto("Rx Received local error { error=%d }", err);
 		err += RXRPC_LOCAL_ERROR_OFFSET;
 		break;

 	case SO_EE_ORIGIN_ICMP6:
 	default:
 		_proto("Rx Received error report { orig=%u }", ee->ee_origin);
 		break;
 	}

 	peer->error_report = err;
 }

 /*
  * Distribute an error that occurred on a peer
  */
 void rxrpc_peer_error_distributor(struct work_struct *work)
 {
 	struct rxrpc_peer *peer =
 		container_of(work, struct rxrpc_peer, error_distributor);
 	struct rxrpc_call *call;
 	enum rxrpc_call_completion compl;
 	int error;

 	_enter("");

 	error = READ_ONCE(peer->error_report);
 	if (error < RXRPC_LOCAL_ERROR_OFFSET) {
 		compl = RXRPC_CALL_NETWORK_ERROR;
 	} else {
 		compl = RXRPC_CALL_LOCAL_ERROR;
 		error -= RXRPC_LOCAL_ERROR_OFFSET;
 	}

 	_debug("ISSUE ERROR %s %d", rxrpc_call_completions[compl], error);

 	spin_lock_bh(&peer->lock);

 	while (!hlist_empty(&peer->error_targets)) {
 		call = hlist_entry(peer->error_targets.first,
 				   struct rxrpc_call, error_link);
 		hlist_del_init(&call->error_link);
 		rxrpc_see_call(call);

 		if (rxrpc_set_call_completion(call, compl, 0, -error))
 			rxrpc_notify_socket(call);
 	}

 	spin_unlock_bh(&peer->lock);

 	rxrpc_put_peer(peer);
 	_leave("");
 }

 /*
  * Add RTT information to cache.  This is called in softirq mode and has
  * exclusive access to the peer RTT data.
  */
 void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
 			rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
 			ktime_t send_time, ktime_t resp_time)
 {
 	struct rxrpc_peer *peer = call->peer;
 	s64 rtt;
 	u64 sum = peer->rtt_sum, avg;
 	u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;

 	rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
 	if (rtt < 0)
 		return;

 	/* Replace the oldest datum in the RTT buffer */
 	sum -= peer->rtt_cache[cursor];
 	sum += rtt;
 	peer->rtt_cache[cursor] = rtt;
 	peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
 	peer->rtt_sum = sum;
 	if (usage < RXRPC_RTT_CACHE_SIZE) {
 		usage++;
 		peer->rtt_usage = usage;
 	}

 	/* Now recalculate the average */
 	if (usage == RXRPC_RTT_CACHE_SIZE) {
 		avg = sum / RXRPC_RTT_CACHE_SIZE;
 	} else {
 		avg = sum;
 		do_div(avg, usage);
 	}

 	peer->rtt = avg;
 	trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
 			   usage, avg);
 }
	/* Peer event handling, typically ICMP messages.
	*
	* 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/errqueue.h>
	#include <linux/udp.h>
	#include <linux/in.h>
	#include <linux/in6.h>
	#include <linux/icmp.h>
	#include <net/sock.h>
	#include <net/af_rxrpc.h>
	#include <net/ip.h>
	#include "ar-internal.h"

	static void rxrpc_store_error(struct rxrpc_peer , struct sock_exterr_skb );

	/*
	* Find the peer associated with an ICMP packet.
	*/
	static struct rxrpc_peer rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local local,
	const struct sk_buff *skb)
	{
	struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
	struct sockaddr_rxrpc srx;

	_enter("");

	memset(&srx, 0, sizeof(srx));
	srx.transport_type = local->srx.transport_type;
	srx.transport_len = local->srx.transport_len;
	srx.transport.family = local->srx.transport.family;

	/* Can we see an ICMP4 packet on an ICMP6 listening socket? and vice
	* versa?
	*/
	switch (srx.transport.family) {
	case AF_INET:
	srx.transport.sin.sin_port = serr->port;
	switch (serr->ee.ee_origin) {
	case SO_EE_ORIGIN_ICMP:
	_net("Rx ICMP");
	memcpy(&srx.transport.sin.sin_addr,
	skb_network_header(skb) + serr->addr_offset,
	sizeof(struct in_addr));
	break;
	case SO_EE_ORIGIN_ICMP6:
	_net("Rx ICMP6 on v4 sock");
	memcpy(&srx.transport.sin.sin_addr,
	skb_network_header(skb) + serr->addr_offset + 12,
	sizeof(struct in_addr));
	break;
	default:
	memcpy(&srx.transport.sin.sin_addr, &ip_hdr(skb)->saddr,
	sizeof(struct in_addr));
	break;
	}
	break;

	#ifdef CONFIG_AF_RXRPC_IPV6
	case AF_INET6:
	srx.transport.sin6.sin6_port = serr->port;
	switch (serr->ee.ee_origin) {
	case SO_EE_ORIGIN_ICMP6:
	_net("Rx ICMP6");
	memcpy(&srx.transport.sin6.sin6_addr,
	skb_network_header(skb) + serr->addr_offset,
	sizeof(struct in6_addr));
	break;
	case SO_EE_ORIGIN_ICMP:
	_net("Rx ICMP on v6 sock");
	srx.transport.sin6.sin6_addr.s6_addr32[0] = 0;
	srx.transport.sin6.sin6_addr.s6_addr32[1] = 0;
	srx.transport.sin6.sin6_addr.s6_addr32[2] = htonl(0xffff);
	memcpy(srx.transport.sin6.sin6_addr.s6_addr + 12,
	skb_network_header(skb) + serr->addr_offset,
	sizeof(struct in_addr));
	break;
	default:
	memcpy(&srx.transport.sin6.sin6_addr,
	&ipv6_hdr(skb)->saddr,
	sizeof(struct in6_addr));
	break;
	}
	break;
	#endif

	default:
	BUG();
	}

	return rxrpc_lookup_peer_rcu(local, &srx);
	}

	/*
	* Handle an MTU/fragmentation problem.
	*/
	static void rxrpc_adjust_mtu(struct rxrpc_peer peer, struct sock_exterr_skb serr)
	{
	u32 mtu = serr->ee.ee_info;

	_net("Rx ICMP Fragmentation Needed (%d)", mtu);

	/* wind down the local interface MTU */
	if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
	peer->if_mtu = mtu;
	_net("I/F MTU %u", mtu);
	}

	if (mtu == 0) {
	/* they didn't give us a size, estimate one */
	mtu = peer->if_mtu;
	if (mtu > 1500) {
	mtu >>= 1;
	if (mtu < 1500)
	mtu = 1500;
	} else {
	mtu -= 100;
	if (mtu < peer->hdrsize)
	mtu = peer->hdrsize + 4;
	}
	}

	if (mtu < peer->mtu) {
	spin_lock_bh(&peer->lock);
	peer->mtu = mtu;
	peer->maxdata = peer->mtu - peer->hdrsize;
	spin_unlock_bh(&peer->lock);
	_net("Net MTU %u (maxdata %u)",
	peer->mtu, peer->maxdata);
	}
	}

	/*
	* Handle an error received on the local endpoint.
	*/
	void rxrpc_error_report(struct sock *sk)
	{
	struct sock_exterr_skb *serr;
	struct rxrpc_local *local = sk->sk_user_data;
	struct rxrpc_peer *peer;
	struct sk_buff *skb;

	_enter("%p{%d}", sk, local->debug_id);

	skb = sock_dequeue_err_skb(sk);
	if (!skb) {
	_leave("UDP socket errqueue empty");
	return;
	}
	rxrpc_new_skb(skb, rxrpc_skb_rx_received);
	serr = SKB_EXT_ERR(skb);
	if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
	_leave("UDP empty message");
	rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
	return;
	}

	rcu_read_lock();
	peer = rxrpc_lookup_peer_icmp_rcu(local, skb);
	if (peer && !rxrpc_get_peer_maybe(peer))
	peer = NULL;
	if (!peer) {
	rcu_read_unlock();
	rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
	_leave(" [no peer]");
	return;
	}

	if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
	serr->ee.ee_type == ICMP_DEST_UNREACH &&
	serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
	rxrpc_adjust_mtu(peer, serr);
	rcu_read_unlock();
	rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
	rxrpc_put_peer(peer);
	_leave(" [MTU update]");
	return;
	}

	rxrpc_store_error(peer, serr);
	rcu_read_unlock();
	rxrpc_free_skb(skb, rxrpc_skb_rx_freed);

	/* The ref we obtained is passed off to the work item */
	rxrpc_queue_work(&peer->error_distributor);
	_leave("");
	}

	/*
	* Map an error report to error codes on the peer record.
	*/
	static void rxrpc_store_error(struct rxrpc_peer *peer,
	struct sock_exterr_skb *serr)
	{
	struct sock_extended_err *ee;
	int err;

	_enter("");

	ee = &serr->ee;

	_net("Rx Error o=%d t=%d c=%d e=%d",
	ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);

	err = ee->ee_errno;

	switch (ee->ee_origin) {
	case SO_EE_ORIGIN_ICMP:
	switch (ee->ee_type) {
	case ICMP_DEST_UNREACH:
	switch (ee->ee_code) {
	case ICMP_NET_UNREACH:
	_net("Rx Received ICMP Network Unreachable");
	break;
	case ICMP_HOST_UNREACH:
	_net("Rx Received ICMP Host Unreachable");
	break;
	case ICMP_PORT_UNREACH:
	_net("Rx Received ICMP Port Unreachable");
	break;
	case ICMP_NET_UNKNOWN:
	_net("Rx Received ICMP Unknown Network");
	break;
	case ICMP_HOST_UNKNOWN:
	_net("Rx Received ICMP Unknown Host");
	break;
	default:
	_net("Rx Received ICMP DestUnreach code=%u",
	ee->ee_code);
	break;
	}
	break;

	case ICMP_TIME_EXCEEDED:
	_net("Rx Received ICMP TTL Exceeded");
	break;

	default:
	_proto("Rx Received ICMP error { type=%u code=%u }",
	ee->ee_type, ee->ee_code);
	break;
	}
	break;

	case SO_EE_ORIGIN_NONE:
	case SO_EE_ORIGIN_LOCAL:
	_proto("Rx Received local error { error=%d }", err);
	err += RXRPC_LOCAL_ERROR_OFFSET;
	break;

	case SO_EE_ORIGIN_ICMP6:
	default:
	_proto("Rx Received error report { orig=%u }", ee->ee_origin);
	break;
	}

	peer->error_report = err;
	}

	/*
	* Distribute an error that occurred on a peer
	*/
	void rxrpc_peer_error_distributor(struct work_struct *work)
	{
	struct rxrpc_peer *peer =
	container_of(work, struct rxrpc_peer, error_distributor);
	struct rxrpc_call *call;
	enum rxrpc_call_completion compl;
	int error;

	_enter("");

	error = READ_ONCE(peer->error_report);
	if (error < RXRPC_LOCAL_ERROR_OFFSET) {
	compl = RXRPC_CALL_NETWORK_ERROR;
	} else {
	compl = RXRPC_CALL_LOCAL_ERROR;
	error -= RXRPC_LOCAL_ERROR_OFFSET;
	}

	_debug("ISSUE ERROR %s %d", rxrpc_call_completions[compl], error);

	spin_lock_bh(&peer->lock);

	while (!hlist_empty(&peer->error_targets)) {
	call = hlist_entry(peer->error_targets.first,
	struct rxrpc_call, error_link);
	hlist_del_init(&call->error_link);
	rxrpc_see_call(call);

	if (rxrpc_set_call_completion(call, compl, 0, -error))
	rxrpc_notify_socket(call);
	}

	spin_unlock_bh(&peer->lock);

	rxrpc_put_peer(peer);
	_leave("");
	}

	/*
	* Add RTT information to cache. This is called in softirq mode and has
	* exclusive access to the peer RTT data.
	*/
	void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
	rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
	ktime_t send_time, ktime_t resp_time)
	{
	struct rxrpc_peer *peer = call->peer;
	s64 rtt;
	u64 sum = peer->rtt_sum, avg;
	u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;

	rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
	if (rtt < 0)
	return;

	/* Replace the oldest datum in the RTT buffer */
	sum -= peer->rtt_cache[cursor];
	sum += rtt;
	peer->rtt_cache[cursor] = rtt;
	peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
	peer->rtt_sum = sum;
	if (usage < RXRPC_RTT_CACHE_SIZE) {
	usage++;
	peer->rtt_usage = usage;
	}

	/* Now recalculate the average */
	if (usage == RXRPC_RTT_CACHE_SIZE) {
	avg = sum / RXRPC_RTT_CACHE_SIZE;
	} else {
	avg = sum;
	do_div(avg, usage);
	}

	peer->rtt = avg;
	trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
	usage, avg);
	}