1 files changed, 349 insertions, 0 deletions

diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c
new file mode 100644
index 000000000..552ba84a2
--- /dev/null
+++ b/net/rxrpc/peer_event.c
@@ -0,0 +1,349 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Peer event handling, typically ICMP messages.
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#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 sk_buff *);
+static void rxrpc_distribute_error(struct rxrpc_peer *, struct sk_buff *,
+				   enum rxrpc_call_completion, int);
+
+/*
+ * Find the peer associated with a local error.
+ */
+static struct rxrpc_peer *rxrpc_lookup_peer_local_rcu(struct rxrpc_local *local,
+						      const struct sk_buff *skb,
+						      struct sockaddr_rxrpc *srx)
+{
+	struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
+
+	_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_len = sizeof(srx->transport.sin);
+		srx->transport.family = AF_INET;
+		srx->transport.sin.sin_port = serr->port;
+		switch (serr->ee.ee_origin) {
+		case SO_EE_ORIGIN_ICMP:
+			memcpy(&srx->transport.sin.sin_addr,
+			       skb_network_header(skb) + serr->addr_offset,
+			       sizeof(struct in_addr));
+			break;
+		case SO_EE_ORIGIN_ICMP6:
+			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:
+		switch (serr->ee.ee_origin) {
+		case SO_EE_ORIGIN_ICMP6:
+			srx->transport.sin6.sin6_port = serr->port;
+			memcpy(&srx->transport.sin6.sin6_addr,
+			       skb_network_header(skb) + serr->addr_offset,
+			       sizeof(struct in6_addr));
+			break;
+		case SO_EE_ORIGIN_ICMP:
+			srx->transport_len = sizeof(srx->transport.sin);
+			srx->transport.family = AF_INET;
+			srx->transport.sin.sin_port = serr->port;
+			memcpy(&srx->transport.sin.sin_addr,
+			       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, unsigned int mtu)
+{
+	/* wind down the local interface MTU */
+	if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu)
+		peer->if_mtu = 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(&peer->lock);
+		peer->mtu = mtu;
+		peer->maxdata = peer->mtu - peer->hdrsize;
+		spin_unlock(&peer->lock);
+	}
+}
+
+/*
+ * Handle an error received on the local endpoint.
+ */
+void rxrpc_input_error(struct rxrpc_local *local, struct sk_buff *skb)
+{
+	struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
+	struct sockaddr_rxrpc srx;
+	struct rxrpc_peer *peer = NULL;
+
+	_enter("L=%x", local->debug_id);
+
+	if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
+		_leave("UDP empty message");
+		return;
+	}
+
+	rcu_read_lock();
+	peer = rxrpc_lookup_peer_local_rcu(local, skb, &srx);
+	if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_input_error))
+		peer = NULL;
+	rcu_read_unlock();
+	if (!peer)
+		return;
+
+	trace_rxrpc_rx_icmp(peer, &serr->ee, &srx);
+
+	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->ee.ee_info);
+		goto out;
+	}
+
+	rxrpc_store_error(peer, skb);
+out:
+	rxrpc_put_peer(peer, rxrpc_peer_put_input_error);
+}
+
+/*
+ * Map an error report to error codes on the peer record.
+ */
+static void rxrpc_store_error(struct rxrpc_peer *peer, struct sk_buff *skb)
+{
+	enum rxrpc_call_completion compl = RXRPC_CALL_NETWORK_ERROR;
+	struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
+	struct sock_extended_err *ee = &serr->ee;
+	int err = ee->ee_errno;
+
+	_enter("");
+
+	switch (ee->ee_origin) {
+	case SO_EE_ORIGIN_NONE:
+	case SO_EE_ORIGIN_LOCAL:
+		compl = RXRPC_CALL_LOCAL_ERROR;
+		break;
+
+	case SO_EE_ORIGIN_ICMP6:
+		if (err == EACCES)
+			err = EHOSTUNREACH;
+		fallthrough;
+	case SO_EE_ORIGIN_ICMP:
+	default:
+		break;
+	}
+
+	rxrpc_distribute_error(peer, skb, compl, err);
+}
+
+/*
+ * Distribute an error that occurred on a peer.
+ */
+static void rxrpc_distribute_error(struct rxrpc_peer *peer, struct sk_buff *skb,
+				   enum rxrpc_call_completion compl, int err)
+{
+	struct rxrpc_call *call;
+	HLIST_HEAD(error_targets);
+
+	spin_lock(&peer->lock);
+	hlist_move_list(&peer->error_targets, &error_targets);
+
+	while (!hlist_empty(&error_targets)) {
+		call = hlist_entry(error_targets.first,
+				   struct rxrpc_call, error_link);
+		hlist_del_init(&call->error_link);
+		spin_unlock(&peer->lock);
+
+		rxrpc_see_call(call, rxrpc_call_see_distribute_error);
+		rxrpc_set_call_completion(call, compl, 0, -err);
+		rxrpc_input_call_event(call, skb);
+
+		spin_lock(&peer->lock);
+	}
+
+	spin_unlock(&peer->lock);
+}
+
+/*
+ * Perform keep-alive pings.
+ */
+static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet,
+					  struct list_head *collector,
+					  time64_t base,
+					  u8 cursor)
+{
+	struct rxrpc_peer *peer;
+	const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
+	time64_t keepalive_at;
+	bool use;
+	int slot;
+
+	spin_lock(&rxnet->peer_hash_lock);
+
+	while (!list_empty(collector)) {
+		peer = list_entry(collector->next,
+				  struct rxrpc_peer, keepalive_link);
+
+		list_del_init(&peer->keepalive_link);
+		if (!rxrpc_get_peer_maybe(peer, rxrpc_peer_get_keepalive))
+			continue;
+
+		use = __rxrpc_use_local(peer->local, rxrpc_local_use_peer_keepalive);
+		spin_unlock(&rxnet->peer_hash_lock);
+
+		if (use) {
+			keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
+			slot = keepalive_at - base;
+			_debug("%02x peer %u t=%d {%pISp}",
+			       cursor, peer->debug_id, slot, &peer->srx.transport);
+
+			if (keepalive_at <= base ||
+			    keepalive_at > base + RXRPC_KEEPALIVE_TIME) {
+				rxrpc_send_keepalive(peer);
+				slot = RXRPC_KEEPALIVE_TIME;
+			}
+
+			/* A transmission to this peer occurred since last we
+			 * examined it so put it into the appropriate future
+			 * bucket.
+			 */
+			slot += cursor;
+			slot &= mask;
+			spin_lock(&rxnet->peer_hash_lock);
+			list_add_tail(&peer->keepalive_link,
+				      &rxnet->peer_keepalive[slot & mask]);
+			spin_unlock(&rxnet->peer_hash_lock);
+			rxrpc_unuse_local(peer->local, rxrpc_local_unuse_peer_keepalive);
+		}
+		rxrpc_put_peer(peer, rxrpc_peer_put_keepalive);
+		spin_lock(&rxnet->peer_hash_lock);
+	}
+
+	spin_unlock(&rxnet->peer_hash_lock);
+}
+
+/*
+ * Perform keep-alive pings with VERSION packets to keep any NAT alive.
+ */
+void rxrpc_peer_keepalive_worker(struct work_struct *work)
+{
+	struct rxrpc_net *rxnet =
+		container_of(work, struct rxrpc_net, peer_keepalive_work);
+	const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
+	time64_t base, now, delay;
+	u8 cursor, stop;
+	LIST_HEAD(collector);
+
+	now = ktime_get_seconds();
+	base = rxnet->peer_keepalive_base;
+	cursor = rxnet->peer_keepalive_cursor;
+	_enter("%lld,%u", base - now, cursor);
+
+	if (!rxnet->live)
+		return;
+
+	/* Remove to a temporary list all the peers that are currently lodged
+	 * in expired buckets plus all new peers.
+	 *
+	 * Everything in the bucket at the cursor is processed this
+	 * second; the bucket at cursor + 1 goes at now + 1s and so
+	 * on...
+	 */
+	spin_lock(&rxnet->peer_hash_lock);
+	list_splice_init(&rxnet->peer_keepalive_new, &collector);
+
+	stop = cursor + ARRAY_SIZE(rxnet->peer_keepalive);
+	while (base <= now && (s8)(cursor - stop) < 0) {
+		list_splice_tail_init(&rxnet->peer_keepalive[cursor & mask],
+				      &collector);
+		base++;
+		cursor++;
+	}
+
+	base = now;
+	spin_unlock(&rxnet->peer_hash_lock);
+
+	rxnet->peer_keepalive_base = base;
+	rxnet->peer_keepalive_cursor = cursor;
+	rxrpc_peer_keepalive_dispatch(rxnet, &collector, base, cursor);
+	ASSERT(list_empty(&collector));
+
+	/* Schedule the timer for the next occupied timeslot. */
+	cursor = rxnet->peer_keepalive_cursor;
+	stop = cursor + RXRPC_KEEPALIVE_TIME - 1;
+	for (; (s8)(cursor - stop) < 0; cursor++) {
+		if (!list_empty(&rxnet->peer_keepalive[cursor & mask]))
+			break;
+		base++;
+	}
+
+	now = ktime_get_seconds();
+	delay = base - now;
+	if (delay < 1)
+		delay = 1;
+	delay *= HZ;
+	if (rxnet->live)
+		timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay);
+
+	_leave("");
+}