1 files changed, 556 insertions, 310 deletions

diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
index 9ed66d533002..f05ea0a88076 100644
--- a/net/rxrpc/recvmsg.c
+++ b/net/rxrpc/recvmsg.c
@@ -19,399 +19,645 @@
 #include "ar-internal.h"
 
 /*
- * removal a call's user ID from the socket tree to make the user ID available
- * again and so that it won't be seen again in association with that call
+ * Post a call for attention by the socket or kernel service.  Further
+ * notifications are suppressed by putting recvmsg_link on a dummy queue.
  */
-void rxrpc_remove_user_ID(struct rxrpc_sock *rx, struct rxrpc_call *call)
+void rxrpc_notify_socket(struct rxrpc_call *call)
 {
-	_debug("RELEASE CALL %d", call->debug_id);
+	struct rxrpc_sock *rx;
+	struct sock *sk;
+
+	_enter("%d", call->debug_id);
+
+	if (!list_empty(&call->recvmsg_link))
+		return;
+
+	rcu_read_lock();
+
+	rx = rcu_dereference(call->socket);
+	sk = &rx->sk;
+	if (rx && sk->sk_state < RXRPC_CLOSE) {
+		if (call->notify_rx) {
+			call->notify_rx(sk, call, call->user_call_ID);
+		} else {
+			write_lock_bh(&rx->recvmsg_lock);
+			if (list_empty(&call->recvmsg_link)) {
+				rxrpc_get_call(call, rxrpc_call_got);
+				list_add_tail(&call->recvmsg_link, &rx->recvmsg_q);
+			}
+			write_unlock_bh(&rx->recvmsg_lock);
 
-	if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
-		write_lock_bh(&rx->call_lock);
-		rb_erase(&call->sock_node, &call->socket->calls);
-		clear_bit(RXRPC_CALL_HAS_USERID, &call->flags);
-		write_unlock_bh(&rx->call_lock);
+			if (!sock_flag(sk, SOCK_DEAD)) {
+				_debug("call %ps", sk->sk_data_ready);
+				sk->sk_data_ready(sk);
+			}
+		}
 	}
 
-	read_lock_bh(&call->state_lock);
-	if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
-	    !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
-		rxrpc_queue_call(call);
-	read_unlock_bh(&call->state_lock);
+	rcu_read_unlock();
+	_leave("");
 }
 
 /*
- * receive a message from an RxRPC socket
- * - we need to be careful about two or more threads calling recvmsg
- *   simultaneously
+ * Pass a call terminating message to userspace.
  */
-int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
-		  int flags)
+static int rxrpc_recvmsg_term(struct rxrpc_call *call, struct msghdr *msg)
 {
-	struct rxrpc_skb_priv *sp;
-	struct rxrpc_call *call = NULL, *continue_call = NULL;
-	struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
-	struct sk_buff *skb;
-	long timeo;
-	int copy, ret, ullen, offset, copied = 0;
-	u32 abort_code;
-
-	DEFINE_WAIT(wait);
-
-	_enter(",,,%zu,%d", len, flags);
-
-	if (flags & (MSG_OOB | MSG_TRUNC))
-		return -EOPNOTSUPP;
-
-	ullen = msg->msg_flags & MSG_CMSG_COMPAT ? 4 : sizeof(unsigned long);
+	u32 tmp = 0;
+	int ret;
+
+	switch (call->completion) {
+	case RXRPC_CALL_SUCCEEDED:
+		ret = 0;
+		if (rxrpc_is_service_call(call))
+			ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &tmp);
+		break;
+	case RXRPC_CALL_REMOTELY_ABORTED:
+		tmp = call->abort_code;
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
+		break;
+	case RXRPC_CALL_LOCALLY_ABORTED:
+		tmp = call->abort_code;
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
+		break;
+	case RXRPC_CALL_NETWORK_ERROR:
+		tmp = call->error;
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &tmp);
+		break;
+	case RXRPC_CALL_LOCAL_ERROR:
+		tmp = call->error;
+		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4, &tmp);
+		break;
+	default:
+		pr_err("Invalid terminal call state %u\n", call->state);
+		BUG();
+		break;
+	}
 
-	timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
-	msg->msg_flags |= MSG_MORE;
+	trace_rxrpc_recvmsg(call, rxrpc_recvmsg_terminal, call->rx_hard_ack,
+			    call->rx_pkt_offset, call->rx_pkt_len, ret);
+	return ret;
+}
 
-	lock_sock(&rx->sk);
+/*
+ * Pass back notification of a new call.  The call is added to the
+ * to-be-accepted list.  This means that the next call to be accepted might not
+ * be the last call seen awaiting acceptance, but unless we leave this on the
+ * front of the queue and block all other messages until someone gives us a
+ * user_ID for it, there's not a lot we can do.
+ */
+static int rxrpc_recvmsg_new_call(struct rxrpc_sock *rx,
+				  struct rxrpc_call *call,
+				  struct msghdr *msg, int flags)
+{
+	int tmp = 0, ret;
 
-	for (;;) {
-		/* return immediately if a client socket has no outstanding
-		 * calls */
-		if (RB_EMPTY_ROOT(&rx->calls)) {
-			if (copied)
-				goto out;
-			if (rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
-				release_sock(&rx->sk);
-				if (continue_call)
-					rxrpc_put_call(continue_call);
-				return -ENODATA;
-			}
-		}
+	ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NEW_CALL, 0, &tmp);
 
-		/* get the next message on the Rx queue */
-		skb = skb_peek(&rx->sk.sk_receive_queue);
-		if (!skb) {
-			/* nothing remains on the queue */
-			if (copied &&
-			    (flags & MSG_PEEK || timeo == 0))
-				goto out;
+	if (ret == 0 && !(flags & MSG_PEEK)) {
+		_debug("to be accepted");
+		write_lock_bh(&rx->recvmsg_lock);
+		list_del_init(&call->recvmsg_link);
+		write_unlock_bh(&rx->recvmsg_lock);
 
-			/* wait for a message to turn up */
-			release_sock(&rx->sk);
-			prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait,
-						  TASK_INTERRUPTIBLE);
-			ret = sock_error(&rx->sk);
-			if (ret)
-				goto wait_error;
-
-			if (skb_queue_empty(&rx->sk.sk_receive_queue)) {
-				if (signal_pending(current))
-					goto wait_interrupted;
-				timeo = schedule_timeout(timeo);
-			}
-			finish_wait(sk_sleep(&rx->sk), &wait);
-			lock_sock(&rx->sk);
-			continue;
-		}
+		rxrpc_get_call(call, rxrpc_call_got);
+		write_lock(&rx->call_lock);
+		list_add_tail(&call->accept_link, &rx->to_be_accepted);
+		write_unlock(&rx->call_lock);
+	}
 
-	peek_next_packet:
-		sp = rxrpc_skb(skb);
-		call = sp->call;
-		ASSERT(call != NULL);
+	trace_rxrpc_recvmsg(call, rxrpc_recvmsg_to_be_accepted, 1, 0, 0, ret);
+	return ret;
+}
 
-		_debug("next pkt %s", rxrpc_pkts[sp->hdr.type]);
+/*
+ * End the packet reception phase.
+ */
+static void rxrpc_end_rx_phase(struct rxrpc_call *call, rxrpc_serial_t serial)
+{
+	_enter("%d,%s", call->debug_id, rxrpc_call_states[call->state]);
 
-		/* make sure we wait for the state to be updated in this call */
-		spin_lock_bh(&call->lock);
-		spin_unlock_bh(&call->lock);
+	trace_rxrpc_receive(call, rxrpc_receive_end, 0, call->rx_top);
+	ASSERTCMP(call->rx_hard_ack, ==, call->rx_top);
 
-		if (test_bit(RXRPC_CALL_RELEASED, &call->flags)) {
-			_debug("packet from released call");
-			if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
-				BUG();
-			rxrpc_free_skb(skb);
-			continue;
-		}
+	if (call->state == RXRPC_CALL_CLIENT_RECV_REPLY) {
+		rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, serial, true, false,
+				  rxrpc_propose_ack_terminal_ack);
+		rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
+	}
 
-		/* determine whether to continue last data receive */
-		if (continue_call) {
-			_debug("maybe cont");
-			if (call != continue_call ||
-			    skb->mark != RXRPC_SKB_MARK_DATA) {
-				release_sock(&rx->sk);
-				rxrpc_put_call(continue_call);
-				_leave(" = %d [noncont]", copied);
-				return copied;
-			}
-		}
+	write_lock_bh(&call->state_lock);
 
-		rxrpc_get_call(call);
+	switch (call->state) {
+	case RXRPC_CALL_CLIENT_RECV_REPLY:
+		__rxrpc_call_completed(call);
+		break;
 
-		/* copy the peer address and timestamp */
-		if (!continue_call) {
-			if (msg->msg_name) {
-				size_t len =
-					sizeof(call->conn->params.peer->srx);
-				memcpy(msg->msg_name,
-				       &call->conn->params.peer->srx, len);
-				msg->msg_namelen = len;
-			}
-			sock_recv_timestamp(msg, &rx->sk, skb);
-		}
+	case RXRPC_CALL_SERVER_RECV_REQUEST:
+		call->tx_phase = true;
+		call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
+		break;
+	default:
+		break;
+	}
 
-		/* receive the message */
-		if (skb->mark != RXRPC_SKB_MARK_DATA)
-			goto receive_non_data_message;
+	write_unlock_bh(&call->state_lock);
+}
 
-		_debug("recvmsg DATA #%u { %d, %d }",
-		       sp->hdr.seq, skb->len, sp->offset);
+/*
+ * Discard a packet we've used up and advance the Rx window by one.
+ */
+static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
+{
+	struct rxrpc_skb_priv *sp;
+	struct sk_buff *skb;
+	rxrpc_serial_t serial;
+	rxrpc_seq_t hard_ack, top;
+	u8 flags;
+	int ix;
+
+	_enter("%d", call->debug_id);
+
+	hard_ack = call->rx_hard_ack;
+	top = smp_load_acquire(&call->rx_top);
+	ASSERT(before(hard_ack, top));
+
+	hard_ack++;
+	ix = hard_ack & RXRPC_RXTX_BUFF_MASK;
+	skb = call->rxtx_buffer[ix];
+	rxrpc_see_skb(skb, rxrpc_skb_rx_rotated);
+	sp = rxrpc_skb(skb);
+	flags = sp->hdr.flags;
+	serial = sp->hdr.serial;
+	if (call->rxtx_annotations[ix] & RXRPC_RX_ANNO_JUMBO)
+		serial += (call->rxtx_annotations[ix] & RXRPC_RX_ANNO_JUMBO) - 1;
+
+	call->rxtx_buffer[ix] = NULL;
+	call->rxtx_annotations[ix] = 0;
+	/* Barrier against rxrpc_input_data(). */
+	smp_store_release(&call->rx_hard_ack, hard_ack);
+
+	rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
+
+	_debug("%u,%u,%02x", hard_ack, top, flags);
+	trace_rxrpc_receive(call, rxrpc_receive_rotate, serial, hard_ack);
+	if (flags & RXRPC_LAST_PACKET) {
+		rxrpc_end_rx_phase(call, serial);
+	} else {
+		/* Check to see if there's an ACK that needs sending. */
+		if (after_eq(hard_ack, call->ackr_consumed + 2) ||
+		    after_eq(top, call->ackr_seen + 2) ||
+		    (hard_ack == top && after(hard_ack, call->ackr_consumed)))
+			rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, 0, serial,
+					  true, false,
+					  rxrpc_propose_ack_rotate_rx);
+		if (call->ackr_reason)
+			rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
+	}
+}
 
-		if (!continue_call) {
-			/* only set the control data once per recvmsg() */
-			ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
-				       ullen, &call->user_call_ID);
-			if (ret < 0)
-				goto copy_error;
-			ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
-		}
+/*
+ * Decrypt and verify a (sub)packet.  The packet's length may be changed due to
+ * padding, but if this is the case, the packet length will be resident in the
+ * socket buffer.  Note that we can't modify the master skb info as the skb may
+ * be the home to multiple subpackets.
+ */
+static int rxrpc_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
+			       u8 annotation,
+			       unsigned int offset, unsigned int len)
+{
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	rxrpc_seq_t seq = sp->hdr.seq;
+	u16 cksum = sp->hdr.cksum;
 
-		ASSERTCMP(sp->hdr.seq, >=, call->rx_data_recv);
-		ASSERTCMP(sp->hdr.seq, <=, call->rx_data_recv + 1);
-		call->rx_data_recv = sp->hdr.seq;
+	_enter("");
 
-		ASSERTCMP(sp->hdr.seq, >, call->rx_data_eaten);
+	/* For all but the head jumbo subpacket, the security checksum is in a
+	 * jumbo header immediately prior to the data.
+	 */
+	if ((annotation & RXRPC_RX_ANNO_JUMBO) > 1) {
+		__be16 tmp;
+		if (skb_copy_bits(skb, offset - 2, &tmp, 2) < 0)
+			BUG();
+		cksum = ntohs(tmp);
+		seq += (annotation & RXRPC_RX_ANNO_JUMBO) - 1;
+	}
 
-		offset = sp->offset;
-		copy = skb->len - offset;
-		if (copy > len - copied)
-			copy = len - copied;
+	return call->conn->security->verify_packet(call, skb, offset, len,
+						   seq, cksum);
+}
 
-		ret = skb_copy_datagram_msg(skb, offset, msg, copy);
+/*
+ * Locate the data within a packet.  This is complicated by:
+ *
+ * (1) An skb may contain a jumbo packet - so we have to find the appropriate
+ *     subpacket.
+ *
+ * (2) The (sub)packets may be encrypted and, if so, the encrypted portion
+ *     contains an extra header which includes the true length of the data,
+ *     excluding any encrypted padding.
+ */
+static int rxrpc_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
+			     u8 *_annotation,
+			     unsigned int *_offset, unsigned int *_len)
+{
+	unsigned int offset = sizeof(struct rxrpc_wire_header);
+	unsigned int len = *_len;
+	int ret;
+	u8 annotation = *_annotation;
+
+	/* Locate the subpacket */
+	len = skb->len - offset;
+	if ((annotation & RXRPC_RX_ANNO_JUMBO) > 0) {
+		offset += (((annotation & RXRPC_RX_ANNO_JUMBO) - 1) *
+			   RXRPC_JUMBO_SUBPKTLEN);
+		len = (annotation & RXRPC_RX_ANNO_JLAST) ?
+			skb->len - offset : RXRPC_JUMBO_SUBPKTLEN;
+	}
 
+	if (!(annotation & RXRPC_RX_ANNO_VERIFIED)) {
+		ret = rxrpc_verify_packet(call, skb, annotation, offset, len);
 		if (ret < 0)
-			goto copy_error;
-
-		/* handle piecemeal consumption of data packets */
-		_debug("copied %d+%d", copy, copied);
+			return ret;
+		*_annotation |= RXRPC_RX_ANNO_VERIFIED;
+	}
 
-		offset += copy;
-		copied += copy;
+	*_offset = offset;
+	*_len = len;
+	call->conn->security->locate_data(call, skb, _offset, _len);
+	return 0;
+}
 
-		if (!(flags & MSG_PEEK))
-			sp->offset = offset;
+/*
+ * Deliver messages to a call.  This keeps processing packets until the buffer
+ * is filled and we find either more DATA (returns 0) or the end of the DATA
+ * (returns 1).  If more packets are required, it returns -EAGAIN.
+ */
+static int rxrpc_recvmsg_data(struct socket *sock, struct rxrpc_call *call,
+			      struct msghdr *msg, struct iov_iter *iter,
+			      size_t len, int flags, size_t *_offset)
+{
+	struct rxrpc_skb_priv *sp;
+	struct sk_buff *skb;
+	rxrpc_seq_t hard_ack, top, seq;
+	size_t remain;
+	bool last;
+	unsigned int rx_pkt_offset, rx_pkt_len;
+	int ix, copy, ret = -EAGAIN, ret2;
+
+	rx_pkt_offset = call->rx_pkt_offset;
+	rx_pkt_len = call->rx_pkt_len;
+
+	if (call->state >= RXRPC_CALL_SERVER_ACK_REQUEST) {
+		seq = call->rx_hard_ack;
+		ret = 1;
+		goto done;
+	}
 
-		if (sp->offset < skb->len) {
-			_debug("buffer full");
-			ASSERTCMP(copied, ==, len);
+	/* Barriers against rxrpc_input_data(). */
+	hard_ack = call->rx_hard_ack;
+	top = smp_load_acquire(&call->rx_top);
+	for (seq = hard_ack + 1; before_eq(seq, top); seq++) {
+		ix = seq & RXRPC_RXTX_BUFF_MASK;
+		skb = call->rxtx_buffer[ix];
+		if (!skb) {
+			trace_rxrpc_recvmsg(call, rxrpc_recvmsg_hole, seq,
+					    rx_pkt_offset, rx_pkt_len, 0);
 			break;
 		}
+		smp_rmb();
+		rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
+		sp = rxrpc_skb(skb);
 
-		/* we transferred the whole data packet */
 		if (!(flags & MSG_PEEK))
-			rxrpc_kernel_data_consumed(call, skb);
-
-		if (sp->hdr.flags & RXRPC_LAST_PACKET) {
-			_debug("last");
-			if (rxrpc_conn_is_client(call->conn)) {
-				 /* last byte of reply received */
-				ret = copied;
-				goto terminal_message;
+			trace_rxrpc_receive(call, rxrpc_receive_front,
+					    sp->hdr.serial, seq);
+
+		if (msg)
+			sock_recv_timestamp(msg, sock->sk, skb);
+
+		if (rx_pkt_offset == 0) {
+			ret2 = rxrpc_locate_data(call, skb,
+						 &call->rxtx_annotations[ix],
+						 &rx_pkt_offset, &rx_pkt_len);
+			trace_rxrpc_recvmsg(call, rxrpc_recvmsg_next, seq,
+					    rx_pkt_offset, rx_pkt_len, ret2);
+			if (ret2 < 0) {
+				ret = ret2;
+				goto out;
 			}
+		} else {
+			trace_rxrpc_recvmsg(call, rxrpc_recvmsg_cont, seq,
+					    rx_pkt_offset, rx_pkt_len, 0);
+		}
 
-			/* last bit of request received */
-			if (!(flags & MSG_PEEK)) {
-				_debug("eat packet");
-				if (skb_dequeue(&rx->sk.sk_receive_queue) !=
-				    skb)
-					BUG();
-				rxrpc_free_skb(skb);
+		/* We have to handle short, empty and used-up DATA packets. */
+		remain = len - *_offset;
+		copy = rx_pkt_len;
+		if (copy > remain)
+			copy = remain;
+		if (copy > 0) {
+			ret2 = skb_copy_datagram_iter(skb, rx_pkt_offset, iter,
+						      copy);
+			if (ret2 < 0) {
+				ret = ret2;
+				goto out;
 			}
-			msg->msg_flags &= ~MSG_MORE;
-			break;
+
+			/* handle piecemeal consumption of data packets */
+			rx_pkt_offset += copy;
+			rx_pkt_len -= copy;
+			*_offset += copy;
 		}
 
-		/* move on to the next data message */
-		_debug("next");
-		if (!continue_call)
-			continue_call = sp->call;
-		else
-			rxrpc_put_call(call);
-		call = NULL;
-
-		if (flags & MSG_PEEK) {
-			_debug("peek next");
-			skb = skb->next;
-			if (skb == (struct sk_buff *) &rx->sk.sk_receive_queue)
-				break;
-			goto peek_next_packet;
+		if (rx_pkt_len > 0) {
+			trace_rxrpc_recvmsg(call, rxrpc_recvmsg_full, seq,
+					    rx_pkt_offset, rx_pkt_len, 0);
+			ASSERTCMP(*_offset, ==, len);
+			ret = 0;
+			break;
 		}
 
-		_debug("eat packet");
-		if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
-			BUG();
-		rxrpc_free_skb(skb);
+		/* The whole packet has been transferred. */
+		last = sp->hdr.flags & RXRPC_LAST_PACKET;
+		if (!(flags & MSG_PEEK))
+			rxrpc_rotate_rx_window(call);
+		rx_pkt_offset = 0;
+		rx_pkt_len = 0;
+
+		if (last) {
+			ASSERTCMP(seq, ==, READ_ONCE(call->rx_top));
+			ret = 1;
+			goto out;
+		}
 	}
 
-	/* end of non-terminal data packet reception for the moment */
-	_debug("end rcv data");
 out:
-	release_sock(&rx->sk);
-	if (call)
-		rxrpc_put_call(call);
-	if (continue_call)
-		rxrpc_put_call(continue_call);
-	_leave(" = %d [data]", copied);
-	return copied;
-
-	/* handle non-DATA messages such as aborts, incoming connections and
-	 * final ACKs */
-receive_non_data_message:
-	_debug("non-data");
-
-	if (skb->mark == RXRPC_SKB_MARK_NEW_CALL) {
-		_debug("RECV NEW CALL");
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NEW_CALL, 0, &abort_code);
-		if (ret < 0)
-			goto copy_error;
-		if (!(flags & MSG_PEEK)) {
-			if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
-				BUG();
-			rxrpc_free_skb(skb);
-		}
-		goto out;
+	if (!(flags & MSG_PEEK)) {
+		call->rx_pkt_offset = rx_pkt_offset;
+		call->rx_pkt_len = rx_pkt_len;
 	}
+done:
+	trace_rxrpc_recvmsg(call, rxrpc_recvmsg_data_return, seq,
+			    rx_pkt_offset, rx_pkt_len, ret);
+	return ret;
+}
 
-	ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
-		       ullen, &call->user_call_ID);
-	if (ret < 0)
-		goto copy_error;
-	ASSERT(test_bit(RXRPC_CALL_HAS_USERID, &call->flags));
+/*
+ * Receive a message from an RxRPC socket
+ * - we need to be careful about two or more threads calling recvmsg
+ *   simultaneously
+ */
+int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
+		  int flags)
+{
+	struct rxrpc_call *call;
+	struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
+	struct list_head *l;
+	size_t copied = 0;
+	long timeo;
+	int ret;
+
+	DEFINE_WAIT(wait);
+
+	trace_rxrpc_recvmsg(NULL, rxrpc_recvmsg_enter, 0, 0, 0, 0);
+
+	if (flags & (MSG_OOB | MSG_TRUNC))
+		return -EOPNOTSUPP;
+
+	timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
+
+try_again:
+	lock_sock(&rx->sk);
+
+	/* Return immediately if a client socket has no outstanding calls */
+	if (RB_EMPTY_ROOT(&rx->calls) &&
+	    list_empty(&rx->recvmsg_q) &&
+	    rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
+		release_sock(&rx->sk);
+		return -ENODATA;
+	}
+
+	if (list_empty(&rx->recvmsg_q)) {
+		ret = -EWOULDBLOCK;
+		if (timeo == 0) {
+			call = NULL;
+			goto error_no_call;
+		}
+
+		release_sock(&rx->sk);
+
+		/* Wait for something to happen */
+		prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait,
+					  TASK_INTERRUPTIBLE);
+		ret = sock_error(&rx->sk);
+		if (ret)
+			goto wait_error;
+
+		if (list_empty(&rx->recvmsg_q)) {
+			if (signal_pending(current))
+				goto wait_interrupted;
+			trace_rxrpc_recvmsg(NULL, rxrpc_recvmsg_wait,
+					    0, 0, 0, 0);
+			timeo = schedule_timeout(timeo);
+		}
+		finish_wait(sk_sleep(&rx->sk), &wait);
+		goto try_again;
+	}
 
-	switch (skb->mark) {
-	case RXRPC_SKB_MARK_DATA:
+	/* Find the next call and dequeue it if we're not just peeking.  If we
+	 * do dequeue it, that comes with a ref that we will need to release.
+	 */
+	write_lock_bh(&rx->recvmsg_lock);
+	l = rx->recvmsg_q.next;
+	call = list_entry(l, struct rxrpc_call, recvmsg_link);
+	if (!(flags & MSG_PEEK))
+		list_del_init(&call->recvmsg_link);
+	else
+		rxrpc_get_call(call, rxrpc_call_got);
+	write_unlock_bh(&rx->recvmsg_lock);
+
+	trace_rxrpc_recvmsg(call, rxrpc_recvmsg_dequeue, 0, 0, 0, 0);
+
+	if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
 		BUG();
-	case RXRPC_SKB_MARK_FINAL_ACK:
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &abort_code);
-		break;
-	case RXRPC_SKB_MARK_BUSY:
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_BUSY, 0, &abort_code);
-		break;
-	case RXRPC_SKB_MARK_REMOTE_ABORT:
-		abort_code = call->remote_abort;
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &abort_code);
-		break;
-	case RXRPC_SKB_MARK_LOCAL_ABORT:
-		abort_code = call->local_abort;
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &abort_code);
-		break;
-	case RXRPC_SKB_MARK_NET_ERROR:
-		_debug("RECV NET ERROR %d", sp->error);
-		abort_code = sp->error;
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &abort_code);
+
+	if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
+		if (flags & MSG_CMSG_COMPAT) {
+			unsigned int id32 = call->user_call_ID;
+
+			ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
+				       sizeof(unsigned int), &id32);
+		} else {
+			ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
+				       sizeof(unsigned long),
+				       &call->user_call_ID);
+		}
+		if (ret < 0)
+			goto error;
+	}
+
+	if (msg->msg_name) {
+		size_t len = sizeof(call->conn->params.peer->srx);
+		memcpy(msg->msg_name, &call->conn->params.peer->srx, len);
+		msg->msg_namelen = len;
+	}
+
+	switch (call->state) {
+	case RXRPC_CALL_SERVER_ACCEPTING:
+		ret = rxrpc_recvmsg_new_call(rx, call, msg, flags);
 		break;
-	case RXRPC_SKB_MARK_LOCAL_ERROR:
-		_debug("RECV LOCAL ERROR %d", sp->error);
-		abort_code = sp->error;
-		ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4,
-			       &abort_code);
+	case RXRPC_CALL_CLIENT_RECV_REPLY:
+	case RXRPC_CALL_SERVER_RECV_REQUEST:
+	case RXRPC_CALL_SERVER_ACK_REQUEST:
+		ret = rxrpc_recvmsg_data(sock, call, msg, &msg->msg_iter, len,
+					 flags, &copied);
+		if (ret == -EAGAIN)
+			ret = 0;
+
+		if (after(call->rx_top, call->rx_hard_ack) &&
+		    call->rxtx_buffer[(call->rx_hard_ack + 1) & RXRPC_RXTX_BUFF_MASK])
+			rxrpc_notify_socket(call);
 		break;
 	default:
-		pr_err("Unknown packet mark %u\n", skb->mark);
-		BUG();
+		ret = 0;
 		break;
 	}
 
 	if (ret < 0)
-		goto copy_error;
-
-terminal_message:
-	_debug("terminal");
-	msg->msg_flags &= ~MSG_MORE;
-	msg->msg_flags |= MSG_EOR;
+		goto error;
 
-	if (!(flags & MSG_PEEK)) {
-		_net("free terminal skb %p", skb);
-		if (skb_dequeue(&rx->sk.sk_receive_queue) != skb)
-			BUG();
-		rxrpc_free_skb(skb);
-		rxrpc_remove_user_ID(rx, call);
+	if (call->state == RXRPC_CALL_COMPLETE) {
+		ret = rxrpc_recvmsg_term(call, msg);
+		if (ret < 0)
+			goto error;
+		if (!(flags & MSG_PEEK))
+			rxrpc_release_call(rx, call);
+		msg->msg_flags |= MSG_EOR;
+		ret = 1;
 	}
 
-	release_sock(&rx->sk);
-	rxrpc_put_call(call);
-	if (continue_call)
-		rxrpc_put_call(continue_call);
-	_leave(" = %d", ret);
-	return ret;
+	if (ret == 0)
+		msg->msg_flags |= MSG_MORE;
+	else
+		msg->msg_flags &= ~MSG_MORE;
+	ret = copied;
 
-copy_error:
-	_debug("copy error");
+error:
+	rxrpc_put_call(call, rxrpc_call_put);
+error_no_call:
 	release_sock(&rx->sk);
-	rxrpc_put_call(call);
-	if (continue_call)
-		rxrpc_put_call(continue_call);
-	_leave(" = %d", ret);
+	trace_rxrpc_recvmsg(call, rxrpc_recvmsg_return, 0, 0, 0, ret);
 	return ret;
 
 wait_interrupted:
 	ret = sock_intr_errno(timeo);
 wait_error:
 	finish_wait(sk_sleep(&rx->sk), &wait);
-	if (continue_call)
-		rxrpc_put_call(continue_call);
-	if (copied)
-		copied = ret;
-	_leave(" = %d [waitfail %d]", copied, ret);
-	return copied;
-
+	call = NULL;
+	goto error_no_call;
 }
 
 /**
- * rxrpc_kernel_is_data_last - Determine if data message is last one
- * @skb: Message holding data
+ * rxrpc_kernel_recv_data - Allow a kernel service to receive data/info
+ * @sock: The socket that the call exists on
+ * @call: The call to send data through
+ * @buf: The buffer to receive into
+ * @size: The size of the buffer, including data already read
+ * @_offset: The running offset into the buffer.
+ * @want_more: True if more data is expected to be read
+ * @_abort: Where the abort code is stored if -ECONNABORTED is returned
  *
- * Determine if data message is last one for the parent call.
+ * Allow a kernel service to receive data and pick up information about the
+ * state of a call.  Returns 0 if got what was asked for and there's more
+ * available, 1 if we got what was asked for and we're at the end of the data
+ * and -EAGAIN if we need more data.
+ *
+ * Note that we may return -EAGAIN to drain empty packets at the end of the
+ * data, even if we've already copied over the requested data.
+ *
+ * This function adds the amount it transfers to *_offset, so this should be
+ * precleared as appropriate.  Note that the amount remaining in the buffer is
+ * taken to be size - *_offset.
+ *
+ * *_abort should also be initialised to 0.
  */
-bool rxrpc_kernel_is_data_last(struct sk_buff *skb)
+int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
+			   void *buf, size_t size, size_t *_offset,
+			   bool want_more, u32 *_abort)
 {
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	struct iov_iter iter;
+	struct kvec iov;
+	int ret;
 
-	ASSERTCMP(skb->mark, ==, RXRPC_SKB_MARK_DATA);
+	_enter("{%d,%s},%zu/%zu,%d",
+	       call->debug_id, rxrpc_call_states[call->state],
+	       *_offset, size, want_more);
 
-	return sp->hdr.flags & RXRPC_LAST_PACKET;
-}
+	ASSERTCMP(*_offset, <=, size);
+	ASSERTCMP(call->state, !=, RXRPC_CALL_SERVER_ACCEPTING);
 
-EXPORT_SYMBOL(rxrpc_kernel_is_data_last);
+	iov.iov_base = buf + *_offset;
+	iov.iov_len = size - *_offset;
+	iov_iter_kvec(&iter, ITER_KVEC | READ, &iov, 1, size - *_offset);
 
-/**
- * rxrpc_kernel_get_abort_code - Get the abort code from an RxRPC abort message
- * @skb: Message indicating an abort
- *
- * Get the abort code from an RxRPC abort message.
- */
-u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb)
-{
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	lock_sock(sock->sk);
+
+	switch (call->state) {
+	case RXRPC_CALL_CLIENT_RECV_REPLY:
+	case RXRPC_CALL_SERVER_RECV_REQUEST:
+	case RXRPC_CALL_SERVER_ACK_REQUEST:
+		ret = rxrpc_recvmsg_data(sock, call, NULL, &iter, size, 0,
+					 _offset);
+		if (ret < 0)
+			goto out;
+
+		/* We can only reach here with a partially full buffer if we
+		 * have reached the end of the data.  We must otherwise have a
+		 * full buffer or have been given -EAGAIN.
+		 */
+		if (ret == 1) {
+			if (*_offset < size)
+				goto short_data;
+			if (!want_more)
+				goto read_phase_complete;
+			ret = 0;
+			goto out;
+		}
+
+		if (!want_more)
+			goto excess_data;
+		goto out;
+
+	case RXRPC_CALL_COMPLETE:
+		goto call_complete;
 
-	switch (skb->mark) {
-	case RXRPC_SKB_MARK_REMOTE_ABORT:
-		return sp->call->remote_abort;
-	case RXRPC_SKB_MARK_LOCAL_ABORT:
-		return sp->call->local_abort;
 	default:
-		BUG();
+		ret = -EINPROGRESS;
+		goto out;
 	}
-}
-
-EXPORT_SYMBOL(rxrpc_kernel_get_abort_code);
 
-/**
- * rxrpc_kernel_get_error - Get the error number from an RxRPC error message
- * @skb: Message indicating an error
- *
- * Get the error number from an RxRPC error message.
- */
-int rxrpc_kernel_get_error_number(struct sk_buff *skb)
-{
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+read_phase_complete:
+	ret = 1;
+out:
+	release_sock(sock->sk);
+	_leave(" = %d [%zu,%d]", ret, *_offset, *_abort);
+	return ret;
 
-	return sp->error;
+short_data:
+	ret = -EBADMSG;
+	goto out;
+excess_data:
+	ret = -EMSGSIZE;
+	goto out;
+call_complete:
+	*_abort = call->abort_code;
+	ret = call->error;
+	if (call->completion == RXRPC_CALL_SUCCEEDED) {
+		ret = 1;
+		if (size > 0)
+			ret = -ECONNRESET;
+	}
+	goto out;
 }
-
-EXPORT_SYMBOL(rxrpc_kernel_get_error_number);
+EXPORT_SYMBOL(rxrpc_kernel_recv_data);