Linux-libre 4.8.2-gnupck-4.8.2-gnu

1 files changed, 757 insertions, 0 deletions

diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
new file mode 100644
index 000000000..70bb77818
--- /dev/null
+++ b/net/rxrpc/input.c
@@ -0,0 +1,757 @@
+/* RxRPC packet reception
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#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 <linux/gfp.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include <net/ip.h>
+#include <net/udp.h>
+#include <net/net_namespace.h>
+#include "ar-internal.h"
+
+/*
+ * queue a packet for recvmsg to pass to userspace
+ * - the caller must hold a lock on call->lock
+ * - must not be called with interrupts disabled (sk_filter() disables BH's)
+ * - eats the packet whether successful or not
+ * - there must be just one reference to the packet, which the caller passes to
+ *   this function
+ */
+int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
+			bool force, bool terminal)
+{
+	struct rxrpc_skb_priv *sp;
+	struct rxrpc_sock *rx = call->socket;
+	struct sock *sk;
+	int ret;
+
+	_enter(",,%d,%d", force, terminal);
+
+	ASSERT(!irqs_disabled());
+
+	sp = rxrpc_skb(skb);
+	ASSERTCMP(sp->call, ==, call);
+
+	/* if we've already posted the terminal message for a call, then we
+	 * don't post any more */
+	if (test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
+		_debug("already terminated");
+		ASSERTCMP(call->state, >=, RXRPC_CALL_COMPLETE);
+		rxrpc_free_skb(skb);
+		return 0;
+	}
+
+	sk = &rx->sk;
+
+	if (!force) {
+		/* cast skb->rcvbuf to unsigned...  It's pointless, but
+		 * reduces number of warnings when compiling with -W
+		 * --ANK */
+//		ret = -ENOBUFS;
+//		if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
+//		    (unsigned int) sk->sk_rcvbuf)
+//			goto out;
+
+		ret = sk_filter(sk, skb);
+		if (ret < 0)
+			goto out;
+	}
+
+	spin_lock_bh(&sk->sk_receive_queue.lock);
+	if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags) &&
+	    !test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
+	    call->socket->sk.sk_state != RXRPC_CLOSE) {
+		skb->destructor = rxrpc_packet_destructor;
+		skb->dev = NULL;
+		skb->sk = sk;
+		atomic_add(skb->truesize, &sk->sk_rmem_alloc);
+
+		if (terminal) {
+			_debug("<<<< TERMINAL MESSAGE >>>>");
+			set_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags);
+		}
+
+		/* allow interception by a kernel service */
+		if (rx->interceptor) {
+			rx->interceptor(sk, call->user_call_ID, skb);
+			spin_unlock_bh(&sk->sk_receive_queue.lock);
+		} else {
+			_net("post skb %p", skb);
+			__skb_queue_tail(&sk->sk_receive_queue, skb);
+			spin_unlock_bh(&sk->sk_receive_queue.lock);
+
+			if (!sock_flag(sk, SOCK_DEAD))
+				sk->sk_data_ready(sk);
+		}
+		skb = NULL;
+	} else {
+		spin_unlock_bh(&sk->sk_receive_queue.lock);
+	}
+	ret = 0;
+
+out:
+	rxrpc_free_skb(skb);
+
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * process a DATA packet, posting the packet to the appropriate queue
+ * - eats the packet if successful
+ */
+static int rxrpc_fast_process_data(struct rxrpc_call *call,
+				   struct sk_buff *skb, u32 seq)
+{
+	struct rxrpc_skb_priv *sp;
+	bool terminal;
+	int ret, ackbit, ack;
+	u32 serial;
+	u8 flags;
+
+	_enter("{%u,%u},,{%u}", call->rx_data_post, call->rx_first_oos, seq);
+
+	sp = rxrpc_skb(skb);
+	ASSERTCMP(sp->call, ==, NULL);
+	flags = sp->hdr.flags;
+	serial = sp->hdr.serial;
+
+	spin_lock(&call->lock);
+
+	if (call->state > RXRPC_CALL_COMPLETE)
+		goto discard;
+
+	ASSERTCMP(call->rx_data_expect, >=, call->rx_data_post);
+	ASSERTCMP(call->rx_data_post, >=, call->rx_data_recv);
+	ASSERTCMP(call->rx_data_recv, >=, call->rx_data_eaten);
+
+	if (seq < call->rx_data_post) {
+		_debug("dup #%u [-%u]", seq, call->rx_data_post);
+		ack = RXRPC_ACK_DUPLICATE;
+		ret = -ENOBUFS;
+		goto discard_and_ack;
+	}
+
+	/* we may already have the packet in the out of sequence queue */
+	ackbit = seq - (call->rx_data_eaten + 1);
+	ASSERTCMP(ackbit, >=, 0);
+	if (__test_and_set_bit(ackbit, call->ackr_window)) {
+		_debug("dup oos #%u [%u,%u]",
+		       seq, call->rx_data_eaten, call->rx_data_post);
+		ack = RXRPC_ACK_DUPLICATE;
+		goto discard_and_ack;
+	}
+
+	if (seq >= call->ackr_win_top) {
+		_debug("exceed #%u [%u]", seq, call->ackr_win_top);
+		__clear_bit(ackbit, call->ackr_window);
+		ack = RXRPC_ACK_EXCEEDS_WINDOW;
+		goto discard_and_ack;
+	}
+
+	if (seq == call->rx_data_expect) {
+		clear_bit(RXRPC_CALL_EXPECT_OOS, &call->flags);
+		call->rx_data_expect++;
+	} else if (seq > call->rx_data_expect) {
+		_debug("oos #%u [%u]", seq, call->rx_data_expect);
+		call->rx_data_expect = seq + 1;
+		if (test_and_set_bit(RXRPC_CALL_EXPECT_OOS, &call->flags)) {
+			ack = RXRPC_ACK_OUT_OF_SEQUENCE;
+			goto enqueue_and_ack;
+		}
+		goto enqueue_packet;
+	}
+
+	if (seq != call->rx_data_post) {
+		_debug("ahead #%u [%u]", seq, call->rx_data_post);
+		goto enqueue_packet;
+	}
+
+	if (test_bit(RXRPC_CALL_RCVD_LAST, &call->flags))
+		goto protocol_error;
+
+	/* if the packet need security things doing to it, then it goes down
+	 * the slow path */
+	if (call->conn->security_ix)
+		goto enqueue_packet;
+
+	sp->call = call;
+	rxrpc_get_call(call);
+	atomic_inc(&call->skb_count);
+	terminal = ((flags & RXRPC_LAST_PACKET) &&
+		    !(flags & RXRPC_CLIENT_INITIATED));
+	ret = rxrpc_queue_rcv_skb(call, skb, false, terminal);
+	if (ret < 0) {
+		if (ret == -ENOMEM || ret == -ENOBUFS) {
+			__clear_bit(ackbit, call->ackr_window);
+			ack = RXRPC_ACK_NOSPACE;
+			goto discard_and_ack;
+		}
+		goto out;
+	}
+
+	skb = NULL;
+	sp = NULL;
+
+	_debug("post #%u", seq);
+	ASSERTCMP(call->rx_data_post, ==, seq);
+	call->rx_data_post++;
+
+	if (flags & RXRPC_LAST_PACKET)
+		set_bit(RXRPC_CALL_RCVD_LAST, &call->flags);
+
+	/* if we've reached an out of sequence packet then we need to drain
+	 * that queue into the socket Rx queue now */
+	if (call->rx_data_post == call->rx_first_oos) {
+		_debug("drain rx oos now");
+		read_lock(&call->state_lock);
+		if (call->state < RXRPC_CALL_COMPLETE &&
+		    !test_and_set_bit(RXRPC_CALL_EV_DRAIN_RX_OOS, &call->events))
+			rxrpc_queue_call(call);
+		read_unlock(&call->state_lock);
+	}
+
+	spin_unlock(&call->lock);
+	atomic_inc(&call->ackr_not_idle);
+	rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, serial, false);
+	_leave(" = 0 [posted]");
+	return 0;
+
+protocol_error:
+	ret = -EBADMSG;
+out:
+	spin_unlock(&call->lock);
+	_leave(" = %d", ret);
+	return ret;
+
+discard_and_ack:
+	_debug("discard and ACK packet %p", skb);
+	__rxrpc_propose_ACK(call, ack, serial, true);
+discard:
+	spin_unlock(&call->lock);
+	rxrpc_free_skb(skb);
+	_leave(" = 0 [discarded]");
+	return 0;
+
+enqueue_and_ack:
+	__rxrpc_propose_ACK(call, ack, serial, true);
+enqueue_packet:
+	_net("defer skb %p", skb);
+	spin_unlock(&call->lock);
+	skb_queue_tail(&call->rx_queue, skb);
+	atomic_inc(&call->ackr_not_idle);
+	read_lock(&call->state_lock);
+	if (call->state < RXRPC_CALL_DEAD)
+		rxrpc_queue_call(call);
+	read_unlock(&call->state_lock);
+	_leave(" = 0 [queued]");
+	return 0;
+}
+
+/*
+ * assume an implicit ACKALL of the transmission phase of a client socket upon
+ * reception of the first reply packet
+ */
+static void rxrpc_assume_implicit_ackall(struct rxrpc_call *call, u32 serial)
+{
+	write_lock_bh(&call->state_lock);
+
+	switch (call->state) {
+	case RXRPC_CALL_CLIENT_AWAIT_REPLY:
+		call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
+		call->acks_latest = serial;
+
+		_debug("implicit ACKALL %%%u", call->acks_latest);
+		set_bit(RXRPC_CALL_EV_RCVD_ACKALL, &call->events);
+		write_unlock_bh(&call->state_lock);
+
+		if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
+			clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
+			clear_bit(RXRPC_CALL_EV_RESEND, &call->events);
+			clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
+		}
+		break;
+
+	default:
+		write_unlock_bh(&call->state_lock);
+		break;
+	}
+}
+
+/*
+ * post an incoming packet to the nominated call to deal with
+ * - must get rid of the sk_buff, either by freeing it or by queuing it
+ */
+void rxrpc_fast_process_packet(struct rxrpc_call *call, struct sk_buff *skb)
+{
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	__be32 wtmp;
+	u32 hi_serial, abort_code;
+
+	_enter("%p,%p", call, skb);
+
+	ASSERT(!irqs_disabled());
+
+#if 0 // INJECT RX ERROR
+	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
+		static int skip = 0;
+		if (++skip == 3) {
+			printk("DROPPED 3RD PACKET!!!!!!!!!!!!!\n");
+			skip = 0;
+			goto free_packet;
+		}
+	}
+#endif
+
+	/* track the latest serial number on this connection for ACK packet
+	 * information */
+	hi_serial = atomic_read(&call->conn->hi_serial);
+	while (sp->hdr.serial > hi_serial)
+		hi_serial = atomic_cmpxchg(&call->conn->hi_serial, hi_serial,
+					   sp->hdr.serial);
+
+	/* request ACK generation for any ACK or DATA packet that requests
+	 * it */
+	if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
+		_proto("ACK Requested on %%%u", sp->hdr.serial);
+		rxrpc_propose_ACK(call, RXRPC_ACK_REQUESTED, sp->hdr.serial, false);
+	}
+
+	switch (sp->hdr.type) {
+	case RXRPC_PACKET_TYPE_ABORT:
+		_debug("abort");
+
+		if (skb_copy_bits(skb, 0, &wtmp, sizeof(wtmp)) < 0)
+			goto protocol_error;
+
+		abort_code = ntohl(wtmp);
+		_proto("Rx ABORT %%%u { %x }", sp->hdr.serial, abort_code);
+
+		write_lock_bh(&call->state_lock);
+		if (call->state < RXRPC_CALL_COMPLETE) {
+			call->state = RXRPC_CALL_REMOTELY_ABORTED;
+			call->remote_abort = abort_code;
+			set_bit(RXRPC_CALL_EV_RCVD_ABORT, &call->events);
+			rxrpc_queue_call(call);
+		}
+		goto free_packet_unlock;
+
+	case RXRPC_PACKET_TYPE_BUSY:
+		_proto("Rx BUSY %%%u", sp->hdr.serial);
+
+		if (rxrpc_conn_is_service(call->conn))
+			goto protocol_error;
+
+		write_lock_bh(&call->state_lock);
+		switch (call->state) {
+		case RXRPC_CALL_CLIENT_SEND_REQUEST:
+			call->state = RXRPC_CALL_SERVER_BUSY;
+			set_bit(RXRPC_CALL_EV_RCVD_BUSY, &call->events);
+			rxrpc_queue_call(call);
+		case RXRPC_CALL_SERVER_BUSY:
+			goto free_packet_unlock;
+		default:
+			goto protocol_error_locked;
+		}
+
+	default:
+		_proto("Rx %s %%%u", rxrpc_pkts[sp->hdr.type], sp->hdr.serial);
+		goto protocol_error;
+
+	case RXRPC_PACKET_TYPE_DATA:
+		_proto("Rx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
+
+		if (sp->hdr.seq == 0)
+			goto protocol_error;
+
+		call->ackr_prev_seq = sp->hdr.seq;
+
+		/* received data implicitly ACKs all of the request packets we
+		 * sent when we're acting as a client */
+		if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
+			rxrpc_assume_implicit_ackall(call, sp->hdr.serial);
+
+		switch (rxrpc_fast_process_data(call, skb, sp->hdr.seq)) {
+		case 0:
+			skb = NULL;
+			goto done;
+
+		default:
+			BUG();
+
+			/* data packet received beyond the last packet */
+		case -EBADMSG:
+			goto protocol_error;
+		}
+
+	case RXRPC_PACKET_TYPE_ACKALL:
+	case RXRPC_PACKET_TYPE_ACK:
+		/* ACK processing is done in process context */
+		read_lock_bh(&call->state_lock);
+		if (call->state < RXRPC_CALL_DEAD) {
+			skb_queue_tail(&call->rx_queue, skb);
+			rxrpc_queue_call(call);
+			skb = NULL;
+		}
+		read_unlock_bh(&call->state_lock);
+		goto free_packet;
+	}
+
+protocol_error:
+	_debug("protocol error");
+	write_lock_bh(&call->state_lock);
+protocol_error_locked:
+	if (call->state <= RXRPC_CALL_COMPLETE) {
+		call->state = RXRPC_CALL_LOCALLY_ABORTED;
+		call->local_abort = RX_PROTOCOL_ERROR;
+		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
+		rxrpc_queue_call(call);
+	}
+free_packet_unlock:
+	write_unlock_bh(&call->state_lock);
+free_packet:
+	rxrpc_free_skb(skb);
+done:
+	_leave("");
+}
+
+/*
+ * split up a jumbo data packet
+ */
+static void rxrpc_process_jumbo_packet(struct rxrpc_call *call,
+				       struct sk_buff *jumbo)
+{
+	struct rxrpc_jumbo_header jhdr;
+	struct rxrpc_skb_priv *sp;
+	struct sk_buff *part;
+
+	_enter(",{%u,%u}", jumbo->data_len, jumbo->len);
+
+	sp = rxrpc_skb(jumbo);
+
+	do {
+		sp->hdr.flags &= ~RXRPC_JUMBO_PACKET;
+
+		/* make a clone to represent the first subpacket in what's left
+		 * of the jumbo packet */
+		part = skb_clone(jumbo, GFP_ATOMIC);
+		if (!part) {
+			/* simply ditch the tail in the event of ENOMEM */
+			pskb_trim(jumbo, RXRPC_JUMBO_DATALEN);
+			break;
+		}
+		rxrpc_new_skb(part);
+
+		pskb_trim(part, RXRPC_JUMBO_DATALEN);
+
+		if (!pskb_pull(jumbo, RXRPC_JUMBO_DATALEN))
+			goto protocol_error;
+
+		if (skb_copy_bits(jumbo, 0, &jhdr, sizeof(jhdr)) < 0)
+			goto protocol_error;
+		if (!pskb_pull(jumbo, sizeof(jhdr)))
+			BUG();
+
+		sp->hdr.seq	+= 1;
+		sp->hdr.serial	+= 1;
+		sp->hdr.flags	= jhdr.flags;
+		sp->hdr._rsvd	= ntohs(jhdr._rsvd);
+
+		_proto("Rx DATA Jumbo %%%u", sp->hdr.serial - 1);
+
+		rxrpc_fast_process_packet(call, part);
+		part = NULL;
+
+	} while (sp->hdr.flags & RXRPC_JUMBO_PACKET);
+
+	rxrpc_fast_process_packet(call, jumbo);
+	_leave("");
+	return;
+
+protocol_error:
+	_debug("protocol error");
+	rxrpc_free_skb(part);
+	rxrpc_free_skb(jumbo);
+	write_lock_bh(&call->state_lock);
+	if (call->state <= RXRPC_CALL_COMPLETE) {
+		call->state = RXRPC_CALL_LOCALLY_ABORTED;
+		call->local_abort = RX_PROTOCOL_ERROR;
+		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
+		rxrpc_queue_call(call);
+	}
+	write_unlock_bh(&call->state_lock);
+	_leave("");
+}
+
+/*
+ * post an incoming packet to the appropriate call/socket to deal with
+ * - must get rid of the sk_buff, either by freeing it or by queuing it
+ */
+static void rxrpc_post_packet_to_call(struct rxrpc_call *call,
+				      struct sk_buff *skb)
+{
+	struct rxrpc_skb_priv *sp;
+
+	_enter("%p,%p", call, skb);
+
+	sp = rxrpc_skb(skb);
+
+	_debug("extant call [%d]", call->state);
+
+	read_lock(&call->state_lock);
+	switch (call->state) {
+	case RXRPC_CALL_LOCALLY_ABORTED:
+		if (!test_and_set_bit(RXRPC_CALL_EV_ABORT, &call->events)) {
+			rxrpc_queue_call(call);
+			goto free_unlock;
+		}
+	case RXRPC_CALL_REMOTELY_ABORTED:
+	case RXRPC_CALL_NETWORK_ERROR:
+	case RXRPC_CALL_DEAD:
+		goto dead_call;
+	case RXRPC_CALL_COMPLETE:
+	case RXRPC_CALL_CLIENT_FINAL_ACK:
+		/* complete server call */
+		if (rxrpc_conn_is_service(call->conn))
+			goto dead_call;
+		/* resend last packet of a completed call */
+		_debug("final ack again");
+		rxrpc_get_call(call);
+		set_bit(RXRPC_CALL_EV_ACK_FINAL, &call->events);
+		rxrpc_queue_call(call);
+		goto free_unlock;
+	default:
+		break;
+	}
+
+	read_unlock(&call->state_lock);
+	rxrpc_get_call(call);
+
+	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
+	    sp->hdr.flags & RXRPC_JUMBO_PACKET)
+		rxrpc_process_jumbo_packet(call, skb);
+	else
+		rxrpc_fast_process_packet(call, skb);
+
+	rxrpc_put_call(call);
+	goto done;
+
+dead_call:
+	if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
+		skb->priority = RX_CALL_DEAD;
+		rxrpc_reject_packet(call->conn->params.local, skb);
+		goto unlock;
+	}
+free_unlock:
+	rxrpc_free_skb(skb);
+unlock:
+	read_unlock(&call->state_lock);
+done:
+	_leave("");
+}
+
+/*
+ * post connection-level events to the connection
+ * - this includes challenges, responses and some aborts
+ */
+static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
+				      struct sk_buff *skb)
+{
+	_enter("%p,%p", conn, skb);
+
+	skb_queue_tail(&conn->rx_queue, skb);
+	rxrpc_queue_conn(conn);
+}
+
+/*
+ * post endpoint-level events to the local endpoint
+ * - this includes debug and version messages
+ */
+static void rxrpc_post_packet_to_local(struct rxrpc_local *local,
+				       struct sk_buff *skb)
+{
+	_enter("%p,%p", local, skb);
+
+	skb_queue_tail(&local->event_queue, skb);
+	rxrpc_queue_local(local);
+}
+
+/*
+ * Extract the wire header from a packet and translate the byte order.
+ */
+static noinline
+int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
+{
+	struct rxrpc_wire_header whdr;
+
+	/* dig out the RxRPC connection details */
+	if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
+		return -EBADMSG;
+	if (!pskb_pull(skb, sizeof(whdr)))
+		BUG();
+
+	memset(sp, 0, sizeof(*sp));
+	sp->hdr.epoch		= ntohl(whdr.epoch);
+	sp->hdr.cid		= ntohl(whdr.cid);
+	sp->hdr.callNumber	= ntohl(whdr.callNumber);
+	sp->hdr.seq		= ntohl(whdr.seq);
+	sp->hdr.serial		= ntohl(whdr.serial);
+	sp->hdr.flags		= whdr.flags;
+	sp->hdr.type		= whdr.type;
+	sp->hdr.userStatus	= whdr.userStatus;
+	sp->hdr.securityIndex	= whdr.securityIndex;
+	sp->hdr._rsvd		= ntohs(whdr._rsvd);
+	sp->hdr.serviceId	= ntohs(whdr.serviceId);
+	return 0;
+}
+
+/*
+ * handle data received on the local endpoint
+ * - may be called in interrupt context
+ *
+ * The socket is locked by the caller and this prevents the socket from being
+ * shut down and the local endpoint from going away, thus sk_user_data will not
+ * be cleared until this function returns.
+ */
+void rxrpc_data_ready(struct sock *sk)
+{
+	struct rxrpc_connection *conn;
+	struct rxrpc_skb_priv *sp;
+	struct rxrpc_local *local = sk->sk_user_data;
+	struct sk_buff *skb;
+	int ret;
+
+	_enter("%p", sk);
+
+	ASSERT(!irqs_disabled());
+
+	skb = skb_recv_datagram(sk, 0, 1, &ret);
+	if (!skb) {
+		if (ret == -EAGAIN)
+			return;
+		_debug("UDP socket error %d", ret);
+		return;
+	}
+
+	rxrpc_new_skb(skb);
+
+	_net("recv skb %p", skb);
+
+	/* we'll probably need to checksum it (didn't call sock_recvmsg) */
+	if (skb_checksum_complete(skb)) {
+		rxrpc_free_skb(skb);
+		__UDP_INC_STATS(&init_net, UDP_MIB_INERRORS, 0);
+		_leave(" [CSUM failed]");
+		return;
+	}
+
+	__UDP_INC_STATS(&init_net, UDP_MIB_INDATAGRAMS, 0);
+
+	/* The socket buffer we have is owned by UDP, with UDP's data all over
+	 * it, but we really want our own data there.
+	 */
+	skb_orphan(skb);
+	sp = rxrpc_skb(skb);
+
+	_net("Rx UDP packet from %08x:%04hu",
+	     ntohl(ip_hdr(skb)->saddr), ntohs(udp_hdr(skb)->source));
+
+	/* dig out the RxRPC connection details */
+	if (rxrpc_extract_header(sp, skb) < 0)
+		goto bad_message;
+
+	_net("Rx RxRPC %s ep=%x call=%x:%x",
+	     sp->hdr.flags & RXRPC_CLIENT_INITIATED ? "ToServer" : "ToClient",
+	     sp->hdr.epoch, sp->hdr.cid, sp->hdr.callNumber);
+
+	if (sp->hdr.type >= RXRPC_N_PACKET_TYPES ||
+	    !((RXRPC_SUPPORTED_PACKET_TYPES >> sp->hdr.type) & 1)) {
+		_proto("Rx Bad Packet Type %u", sp->hdr.type);
+		goto bad_message;
+	}
+
+	if (sp->hdr.type == RXRPC_PACKET_TYPE_VERSION) {
+		rxrpc_post_packet_to_local(local, skb);
+		goto out;
+	}
+
+	if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
+	    (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
+		goto bad_message;
+
+	rcu_read_lock();
+
+	conn = rxrpc_find_connection_rcu(local, skb);
+	if (!conn)
+		goto cant_route_call;
+
+	if (sp->hdr.callNumber == 0) {
+		/* Connection-level packet */
+		_debug("CONN %p {%d}", conn, conn->debug_id);
+		rxrpc_post_packet_to_conn(conn, skb);
+	} else {
+		/* Call-bound packets are routed by connection channel. */
+		unsigned int channel = sp->hdr.cid & RXRPC_CHANNELMASK;
+		struct rxrpc_channel *chan = &conn->channels[channel];
+		struct rxrpc_call *call = rcu_dereference(chan->call);
+
+		if (!call || atomic_read(&call->usage) == 0)
+			goto cant_route_call;
+
+		rxrpc_post_packet_to_call(call, skb);
+	}
+
+	rcu_read_unlock();
+out:
+	return;
+
+cant_route_call:
+	rcu_read_unlock();
+
+	_debug("can't route call");
+	if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
+	    sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {
+		if (sp->hdr.seq == 1) {
+			_debug("first packet");
+			skb_queue_tail(&local->accept_queue, skb);
+			rxrpc_queue_work(&local->processor);
+			_leave(" [incoming]");
+			return;
+		}
+		skb->priority = RX_INVALID_OPERATION;
+	} else {
+		skb->priority = RX_CALL_DEAD;
+	}
+
+	if (sp->hdr.type != RXRPC_PACKET_TYPE_ABORT) {
+		_debug("reject type %d",sp->hdr.type);
+		rxrpc_reject_packet(local, skb);
+	} else {
+		rxrpc_free_skb(skb);
+	}
+	_leave(" [no call]");
+	return;
+
+bad_message:
+	skb->priority = RX_PROTOCOL_ERROR;
+	rxrpc_reject_packet(local, skb);
+	_leave(" [badmsg]");
+}