1 files changed, 325 insertions, 608 deletions

diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index f4bda06b7d2d..0d47db886f6e 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -14,336 +14,326 @@
 #include <linux/net.h>
 #include <linux/gfp.h>
 #include <linux/skbuff.h>
-#include <linux/circ_buf.h>
 #include <linux/export.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
 #include "ar-internal.h"
 
-/*
- * Time till packet resend (in jiffies).
- */
-unsigned int rxrpc_resend_timeout = 4 * HZ;
-
-static int rxrpc_send_data(struct rxrpc_sock *rx,
-			   struct rxrpc_call *call,
-			   struct msghdr *msg, size_t len);
+struct rxrpc_pkt_buffer {
+	struct rxrpc_wire_header whdr;
+	union {
+		struct {
+			struct rxrpc_ackpacket ack;
+			u8 acks[255];
+			u8 pad[3];
+		};
+		__be32 abort_code;
+	};
+	struct rxrpc_ackinfo ackinfo;
+};
 
 /*
- * extract control messages from the sendmsg() control buffer
+ * Fill out an ACK packet.
  */
-static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
-			      unsigned long *user_call_ID,
-			      enum rxrpc_command *command,
-			      u32 *abort_code,
-			      bool *_exclusive)
+static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
+				 struct rxrpc_pkt_buffer *pkt,
+				 rxrpc_seq_t *_hard_ack,
+				 rxrpc_seq_t *_top)
 {
-	struct cmsghdr *cmsg;
-	bool got_user_ID = false;
-	int len;
-
-	*command = RXRPC_CMD_SEND_DATA;
-
-	if (msg->msg_controllen == 0)
-		return -EINVAL;
-
-	for_each_cmsghdr(cmsg, msg) {
-		if (!CMSG_OK(msg, cmsg))
-			return -EINVAL;
-
-		len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
-		_debug("CMSG %d, %d, %d",
-		       cmsg->cmsg_level, cmsg->cmsg_type, len);
-
-		if (cmsg->cmsg_level != SOL_RXRPC)
-			continue;
-
-		switch (cmsg->cmsg_type) {
-		case RXRPC_USER_CALL_ID:
-			if (msg->msg_flags & MSG_CMSG_COMPAT) {
-				if (len != sizeof(u32))
-					return -EINVAL;
-				*user_call_ID = *(u32 *) CMSG_DATA(cmsg);
-			} else {
-				if (len != sizeof(unsigned long))
-					return -EINVAL;
-				*user_call_ID = *(unsigned long *)
-					CMSG_DATA(cmsg);
-			}
-			_debug("User Call ID %lx", *user_call_ID);
-			got_user_ID = true;
-			break;
-
-		case RXRPC_ABORT:
-			if (*command != RXRPC_CMD_SEND_DATA)
-				return -EINVAL;
-			*command = RXRPC_CMD_SEND_ABORT;
-			if (len != sizeof(*abort_code))
-				return -EINVAL;
-			*abort_code = *(unsigned int *) CMSG_DATA(cmsg);
-			_debug("Abort %x", *abort_code);
-			if (*abort_code == 0)
-				return -EINVAL;
-			break;
-
-		case RXRPC_ACCEPT:
-			if (*command != RXRPC_CMD_SEND_DATA)
-				return -EINVAL;
-			*command = RXRPC_CMD_ACCEPT;
-			if (len != 0)
-				return -EINVAL;
-			break;
-
-		case RXRPC_EXCLUSIVE_CALL:
-			*_exclusive = true;
-			if (len != 0)
-				return -EINVAL;
-			break;
-		default:
-			return -EINVAL;
-		}
+	rxrpc_serial_t serial;
+	rxrpc_seq_t hard_ack, top, seq;
+	int ix;
+	u32 mtu, jmax;
+	u8 *ackp = pkt->acks;
+
+	/* Barrier against rxrpc_input_data(). */
+	serial = call->ackr_serial;
+	hard_ack = READ_ONCE(call->rx_hard_ack);
+	top = smp_load_acquire(&call->rx_top);
+	*_hard_ack = hard_ack;
+	*_top = top;
+
+	pkt->ack.bufferSpace	= htons(8);
+	pkt->ack.maxSkew	= htons(call->ackr_skew);
+	pkt->ack.firstPacket	= htonl(hard_ack + 1);
+	pkt->ack.previousPacket	= htonl(call->ackr_prev_seq);
+	pkt->ack.serial		= htonl(serial);
+	pkt->ack.reason		= call->ackr_reason;
+	pkt->ack.nAcks		= top - hard_ack;
+
+	if (pkt->ack.reason == RXRPC_ACK_PING)
+		pkt->whdr.flags |= RXRPC_REQUEST_ACK;
+
+	if (after(top, hard_ack)) {
+		seq = hard_ack + 1;
+		do {
+			ix = seq & RXRPC_RXTX_BUFF_MASK;
+			if (call->rxtx_buffer[ix])
+				*ackp++ = RXRPC_ACK_TYPE_ACK;
+			else
+				*ackp++ = RXRPC_ACK_TYPE_NACK;
+			seq++;
+		} while (before_eq(seq, top));
 	}
 
-	if (!got_user_ID)
-		return -EINVAL;
-	_leave(" = 0");
-	return 0;
+	mtu = call->conn->params.peer->if_mtu;
+	mtu -= call->conn->params.peer->hdrsize;
+	jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
+	pkt->ackinfo.rxMTU	= htonl(rxrpc_rx_mtu);
+	pkt->ackinfo.maxMTU	= htonl(mtu);
+	pkt->ackinfo.rwind	= htonl(call->rx_winsize);
+	pkt->ackinfo.jumbo_max	= htonl(jmax);
+
+	*ackp++ = 0;
+	*ackp++ = 0;
+	*ackp++ = 0;
+	return top - hard_ack + 3;
 }
 
 /*
- * abort a call, sending an ABORT packet to the peer
+ * Send an ACK or ABORT call packet.
  */
-static void rxrpc_send_abort(struct rxrpc_call *call, u32 abort_code)
+int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
 {
-	write_lock_bh(&call->state_lock);
-
-	if (call->state <= RXRPC_CALL_COMPLETE) {
-		call->state = RXRPC_CALL_LOCALLY_ABORTED;
-		call->local_abort = abort_code;
-		set_bit(RXRPC_CALL_EV_ABORT, &call->events);
-		del_timer_sync(&call->resend_timer);
-		del_timer_sync(&call->ack_timer);
-		clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
-		clear_bit(RXRPC_CALL_EV_ACK, &call->events);
-		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
-		rxrpc_queue_call(call);
+	struct rxrpc_connection *conn = NULL;
+	struct rxrpc_pkt_buffer *pkt;
+	struct msghdr msg;
+	struct kvec iov[2];
+	rxrpc_serial_t serial;
+	rxrpc_seq_t hard_ack, top;
+	size_t len, n;
+	bool ping = false;
+	int ioc, ret;
+	u32 abort_code;
+
+	_enter("%u,%s", call->debug_id, rxrpc_pkts[type]);
+
+	spin_lock_bh(&call->lock);
+	if (call->conn)
+		conn = rxrpc_get_connection_maybe(call->conn);
+	spin_unlock_bh(&call->lock);
+	if (!conn)
+		return -ECONNRESET;
+
+	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+	if (!pkt) {
+		rxrpc_put_connection(conn);
+		return -ENOMEM;
 	}
 
-	write_unlock_bh(&call->state_lock);
-}
-
-/*
- * Create a new client call for sendmsg().
- */
-static struct rxrpc_call *
-rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
-				  unsigned long user_call_ID, bool exclusive)
-{
-	struct rxrpc_conn_parameters cp;
-	struct rxrpc_call *call;
-	struct key *key;
-
-	DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
+	msg.msg_name	= &call->peer->srx.transport;
+	msg.msg_namelen	= call->peer->srx.transport_len;
+	msg.msg_control	= NULL;
+	msg.msg_controllen = 0;
+	msg.msg_flags	= 0;
+
+	pkt->whdr.epoch		= htonl(conn->proto.epoch);
+	pkt->whdr.cid		= htonl(call->cid);
+	pkt->whdr.callNumber	= htonl(call->call_id);
+	pkt->whdr.seq		= 0;
+	pkt->whdr.type		= type;
+	pkt->whdr.flags		= conn->out_clientflag;
+	pkt->whdr.userStatus	= 0;
+	pkt->whdr.securityIndex	= call->security_ix;
+	pkt->whdr._rsvd		= 0;
+	pkt->whdr.serviceId	= htons(call->service_id);
+
+	iov[0].iov_base	= pkt;
+	iov[0].iov_len	= sizeof(pkt->whdr);
+	len = sizeof(pkt->whdr);
+
+	switch (type) {
+	case RXRPC_PACKET_TYPE_ACK:
+		spin_lock_bh(&call->lock);
+		if (!call->ackr_reason) {
+			spin_unlock_bh(&call->lock);
+			ret = 0;
+			goto out;
+		}
+		ping = (call->ackr_reason == RXRPC_ACK_PING);
+		n = rxrpc_fill_out_ack(call, pkt, &hard_ack, &top);
+		call->ackr_reason = 0;
 
-	_enter("");
+		spin_unlock_bh(&call->lock);
 
-	if (!msg->msg_name)
-		return ERR_PTR(-EDESTADDRREQ);
 
-	key = rx->key;
-	if (key && !rx->key->payload.data[0])
-		key = NULL;
+		pkt->whdr.flags |= RXRPC_SLOW_START_OK;
 
-	memset(&cp, 0, sizeof(cp));
-	cp.local		= rx->local;
-	cp.key			= rx->key;
-	cp.security_level	= rx->min_sec_level;
-	cp.exclusive		= rx->exclusive | exclusive;
-	cp.service_id		= srx->srx_service;
-	call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL);
+		iov[0].iov_len += sizeof(pkt->ack) + n;
+		iov[1].iov_base = &pkt->ackinfo;
+		iov[1].iov_len	= sizeof(pkt->ackinfo);
+		len += sizeof(pkt->ack) + n + sizeof(pkt->ackinfo);
+		ioc = 2;
+		break;
 
-	_leave(" = %p\n", call);
-	return call;
-}
+	case RXRPC_PACKET_TYPE_ABORT:
+		abort_code = call->abort_code;
+		pkt->abort_code = htonl(abort_code);
+		iov[0].iov_len += sizeof(pkt->abort_code);
+		len += sizeof(pkt->abort_code);
+		ioc = 1;
+		break;
 
-/*
- * send a message forming part of a client call through an RxRPC socket
- * - caller holds the socket locked
- * - the socket may be either a client socket or a server socket
- */
-int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
-{
-	enum rxrpc_command cmd;
-	struct rxrpc_call *call;
-	unsigned long user_call_ID = 0;
-	bool exclusive = false;
-	u32 abort_code = 0;
-	int ret;
-
-	_enter("");
-
-	ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code,
-				 &exclusive);
-	if (ret < 0)
-		return ret;
-
-	if (cmd == RXRPC_CMD_ACCEPT) {
-		if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
-			return -EINVAL;
-		call = rxrpc_accept_call(rx, user_call_ID);
-		if (IS_ERR(call))
-			return PTR_ERR(call);
-		rxrpc_put_call(call);
-		return 0;
+	default:
+		BUG();
+		ret = -ENOANO;
+		goto out;
 	}
 
-	call = rxrpc_find_call_by_user_ID(rx, user_call_ID);
-	if (!call) {
-		if (cmd != RXRPC_CMD_SEND_DATA)
-			return -EBADSLT;
-		call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID,
-							 exclusive);
-		if (IS_ERR(call))
-			return PTR_ERR(call);
+	serial = atomic_inc_return(&conn->serial);
+	pkt->whdr.serial = htonl(serial);
+	switch (type) {
+	case RXRPC_PACKET_TYPE_ACK:
+		trace_rxrpc_tx_ack(call, serial,
+				   ntohl(pkt->ack.firstPacket),
+				   ntohl(pkt->ack.serial),
+				   pkt->ack.reason, pkt->ack.nAcks);
+		break;
 	}
 
-	_debug("CALL %d USR %lx ST %d on CONN %p",
-	       call->debug_id, call->user_call_ID, call->state, call->conn);
-
-	if (call->state >= RXRPC_CALL_COMPLETE) {
-		/* it's too late for this call */
-		ret = -ECONNRESET;
-	} else if (cmd == RXRPC_CMD_SEND_ABORT) {
-		rxrpc_send_abort(call, abort_code);
-		ret = 0;
-	} else if (cmd != RXRPC_CMD_SEND_DATA) {
-		ret = -EINVAL;
-	} else if (!call->in_clientflag &&
-		   call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
-		/* request phase complete for this client call */
-		ret = -EPROTO;
-	} else if (call->in_clientflag &&
-		   call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
-		   call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
-		/* Reply phase not begun or not complete for service call. */
-		ret = -EPROTO;
-	} else {
-		ret = rxrpc_send_data(rx, call, msg, len);
+	if (ping) {
+		call->ackr_ping = serial;
+		smp_wmb();
+		/* We need to stick a time in before we send the packet in case
+		 * the reply gets back before kernel_sendmsg() completes - but
+		 * asking UDP to send the packet can take a relatively long
+		 * time, so we update the time after, on the assumption that
+		 * the packet transmission is more likely to happen towards the
+		 * end of the kernel_sendmsg() call.
+		 */
+		call->ackr_ping_time = ktime_get_real();
+		set_bit(RXRPC_CALL_PINGING, &call->flags);
+		trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_ping, serial);
 	}
-
-	rxrpc_put_call(call);
-	_leave(" = %d", ret);
-	return ret;
-}
-
-/**
- * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
- * @call: The call to send data through
- * @msg: The data to send
- * @len: The amount of data to send
- *
- * Allow a kernel service to send data on a call.  The call must be in an state
- * appropriate to sending data.  No control data should be supplied in @msg,
- * nor should an address be supplied.  MSG_MORE should be flagged if there's
- * more data to come, otherwise this data will end the transmission phase.
- */
-int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
-			   size_t len)
-{
-	int ret;
-
-	_enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
-
-	ASSERTCMP(msg->msg_name, ==, NULL);
-	ASSERTCMP(msg->msg_control, ==, NULL);
-
-	lock_sock(&call->socket->sk);
-
-	_debug("CALL %d USR %lx ST %d on CONN %p",
-	       call->debug_id, call->user_call_ID, call->state, call->conn);
-
-	if (call->state >= RXRPC_CALL_COMPLETE) {
-		ret = -ESHUTDOWN; /* it's too late for this call */
-	} else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
-		   call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
-		   call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
-		ret = -EPROTO; /* request phase complete for this client call */
-	} else {
-		ret = rxrpc_send_data(call->socket, call, msg, len);
+	ret = kernel_sendmsg(conn->params.local->socket,
+			     &msg, iov, ioc, len);
+	if (ping)
+		call->ackr_ping_time = ktime_get_real();
+
+	if (type == RXRPC_PACKET_TYPE_ACK &&
+	    call->state < RXRPC_CALL_COMPLETE) {
+		if (ret < 0) {
+			clear_bit(RXRPC_CALL_PINGING, &call->flags);
+			rxrpc_propose_ACK(call, pkt->ack.reason,
+					  ntohs(pkt->ack.maxSkew),
+					  ntohl(pkt->ack.serial),
+					  true, true,
+					  rxrpc_propose_ack_retry_tx);
+		} else {
+			spin_lock_bh(&call->lock);
+			if (after(hard_ack, call->ackr_consumed))
+				call->ackr_consumed = hard_ack;
+			if (after(top, call->ackr_seen))
+				call->ackr_seen = top;
+			spin_unlock_bh(&call->lock);
+		}
 	}
 
-	release_sock(&call->socket->sk);
-	_leave(" = %d", ret);
+out:
+	rxrpc_put_connection(conn);
+	kfree(pkt);
 	return ret;
 }
 
-EXPORT_SYMBOL(rxrpc_kernel_send_data);
-
-/**
- * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
- * @call: The call to be aborted
- * @abort_code: The abort code to stick into the ABORT packet
- *
- * Allow a kernel service to abort a call, if it's still in an abortable state.
- */
-void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code)
-{
-	_enter("{%d},%d", call->debug_id, abort_code);
-
-	lock_sock(&call->socket->sk);
-
-	_debug("CALL %d USR %lx ST %d on CONN %p",
-	       call->debug_id, call->user_call_ID, call->state, call->conn);
-
-	if (call->state < RXRPC_CALL_COMPLETE)
-		rxrpc_send_abort(call, abort_code);
-
-	release_sock(&call->socket->sk);
-	_leave("");
-}
-
-EXPORT_SYMBOL(rxrpc_kernel_abort_call);
-
 /*
  * send a packet through the transport endpoint
  */
-int rxrpc_send_data_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
+int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
+			   bool retrans)
 {
-	struct kvec iov[1];
+	struct rxrpc_connection *conn = call->conn;
+	struct rxrpc_wire_header whdr;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	struct msghdr msg;
+	struct kvec iov[2];
+	rxrpc_serial_t serial;
+	size_t len;
+	bool lost = false;
 	int ret, opt;
 
 	_enter(",{%d}", skb->len);
 
-	iov[0].iov_base = skb->head;
-	iov[0].iov_len = skb->len;
+	/* Each transmission of a Tx packet needs a new serial number */
+	serial = atomic_inc_return(&conn->serial);
+
+	whdr.epoch	= htonl(conn->proto.epoch);
+	whdr.cid	= htonl(call->cid);
+	whdr.callNumber	= htonl(call->call_id);
+	whdr.seq	= htonl(sp->hdr.seq);
+	whdr.serial	= htonl(serial);
+	whdr.type	= RXRPC_PACKET_TYPE_DATA;
+	whdr.flags	= sp->hdr.flags;
+	whdr.userStatus	= 0;
+	whdr.securityIndex = call->security_ix;
+	whdr._rsvd	= htons(sp->hdr._rsvd);
+	whdr.serviceId	= htons(call->service_id);
+
+	iov[0].iov_base = &whdr;
+	iov[0].iov_len = sizeof(whdr);
+	iov[1].iov_base = skb->head;
+	iov[1].iov_len = skb->len;
+	len = iov[0].iov_len + iov[1].iov_len;
 
-	msg.msg_name = &conn->params.peer->srx.transport;
-	msg.msg_namelen = conn->params.peer->srx.transport_len;
+	msg.msg_name = &call->peer->srx.transport;
+	msg.msg_namelen = call->peer->srx.transport_len;
 	msg.msg_control = NULL;
 	msg.msg_controllen = 0;
 	msg.msg_flags = 0;
 
-	/* send the packet with the don't fragment bit set if we currently
-	 * think it's small enough */
-	if (skb->len - sizeof(struct rxrpc_wire_header) < conn->params.peer->maxdata) {
-		down_read(&conn->params.local->defrag_sem);
-		/* send the packet by UDP
-		 * - returns -EMSGSIZE if UDP would have to fragment the packet
-		 *   to go out of the interface
-		 *   - in which case, we'll have processed the ICMP error
-		 *     message and update the peer record
-		 */
-		ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
-				     iov[0].iov_len);
+	/* If our RTT cache needs working on, request an ACK.  Also request
+	 * ACKs if a DATA packet appears to have been lost.
+	 */
+	if (retrans ||
+	    call->cong_mode == RXRPC_CALL_SLOW_START ||
+	    (call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
+	    ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
+			 ktime_get_real()))
+		whdr.flags |= RXRPC_REQUEST_ACK;
+
+	if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
+		static int lose;
+		if ((lose++ & 7) == 7) {
+			ret = 0;
+			lost = true;
+			goto done;
+		}
+	}
 
-		up_read(&conn->params.local->defrag_sem);
-		if (ret == -EMSGSIZE)
-			goto send_fragmentable;
+	_proto("Tx DATA %%%u { #%u }", serial, sp->hdr.seq);
 
-		_leave(" = %d [%u]", ret, conn->params.peer->maxdata);
-		return ret;
+	/* send the packet with the don't fragment bit set if we currently
+	 * think it's small enough */
+	if (iov[1].iov_len >= call->peer->maxdata)
+		goto send_fragmentable;
+
+	down_read(&conn->params.local->defrag_sem);
+	/* send the packet by UDP
+	 * - returns -EMSGSIZE if UDP would have to fragment the packet
+	 *   to go out of the interface
+	 *   - in which case, we'll have processed the ICMP error
+	 *     message and update the peer record
+	 */
+	ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
+
+	up_read(&conn->params.local->defrag_sem);
+	if (ret == -EMSGSIZE)
+		goto send_fragmentable;
+
+done:
+	trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags,
+			    retrans, lost);
+	if (ret >= 0) {
+		ktime_t now = ktime_get_real();
+		skb->tstamp = now;
+		smp_wmb();
+		sp->hdr.serial = serial;
+		if (whdr.flags & RXRPC_REQUEST_ACK) {
+			call->peer->rtt_last_req = now;
+			trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
+		}
 	}
+	_leave(" = %d [%u]", ret, call->peer->maxdata);
+	return ret;
 
 send_fragmentable:
 	/* attempt to send this message with fragmentation enabled */
@@ -358,8 +348,8 @@ send_fragmentable:
 					SOL_IP, IP_MTU_DISCOVER,
 					(char *)&opt, sizeof(opt));
 		if (ret == 0) {
-			ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
-					     iov[0].iov_len);
+			ret = kernel_sendmsg(conn->params.local->socket, &msg,
+					     iov, 2, len);
 
 			opt = IP_PMTUDISC_DO;
 			kernel_setsockopt(conn->params.local->socket, SOL_IP,
@@ -367,355 +357,82 @@ send_fragmentable:
 					  (char *)&opt, sizeof(opt));
 		}
 		break;
-	}
-
-	up_write(&conn->params.local->defrag_sem);
-	_leave(" = %d [frag %u]", ret, conn->params.peer->maxdata);
-	return ret;
-}
 
-/*
- * wait for space to appear in the transmit/ACK window
- * - caller holds the socket locked
- */
-static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
-				    struct rxrpc_call *call,
-				    long *timeo)
-{
-	DECLARE_WAITQUEUE(myself, current);
-	int ret;
-
-	_enter(",{%d},%ld",
-	       CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail),
-			  call->acks_winsz),
-	       *timeo);
-
-	add_wait_queue(&call->tx_waitq, &myself);
-
-	for (;;) {
-		set_current_state(TASK_INTERRUPTIBLE);
-		ret = 0;
-		if (CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail),
-			       call->acks_winsz) > 0)
-			break;
-		if (signal_pending(current)) {
-			ret = sock_intr_errno(*timeo);
-			break;
-		}
-
-		release_sock(&rx->sk);
-		*timeo = schedule_timeout(*timeo);
-		lock_sock(&rx->sk);
-	}
-
-	remove_wait_queue(&call->tx_waitq, &myself);
-	set_current_state(TASK_RUNNING);
-	_leave(" = %d", ret);
-	return ret;
-}
-
-/*
- * attempt to schedule an instant Tx resend
- */
-static inline void rxrpc_instant_resend(struct rxrpc_call *call)
-{
-	read_lock_bh(&call->state_lock);
-	if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
-		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
-		if (call->state < RXRPC_CALL_COMPLETE &&
-		    !test_and_set_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events))
-			rxrpc_queue_call(call);
-	}
-	read_unlock_bh(&call->state_lock);
-}
+#ifdef CONFIG_AF_RXRPC_IPV6
+	case AF_INET6:
+		opt = IPV6_PMTUDISC_DONT;
+		ret = kernel_setsockopt(conn->params.local->socket,
+					SOL_IPV6, IPV6_MTU_DISCOVER,
+					(char *)&opt, sizeof(opt));
+		if (ret == 0) {
+			ret = kernel_sendmsg(conn->params.local->socket, &msg,
+					     iov, 1, iov[0].iov_len);
 
-/*
- * queue a packet for transmission, set the resend timer and attempt
- * to send the packet immediately
- */
-static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
-			       bool last)
-{
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	int ret;
-
-	_net("queue skb %p [%d]", skb, call->acks_head);
-
-	ASSERT(call->acks_window != NULL);
-	call->acks_window[call->acks_head] = (unsigned long) skb;
-	smp_wmb();
-	call->acks_head = (call->acks_head + 1) & (call->acks_winsz - 1);
-
-	if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
-		_debug("________awaiting reply/ACK__________");
-		write_lock_bh(&call->state_lock);
-		switch (call->state) {
-		case RXRPC_CALL_CLIENT_SEND_REQUEST:
-			call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
-			break;
-		case RXRPC_CALL_SERVER_ACK_REQUEST:
-			call->state = RXRPC_CALL_SERVER_SEND_REPLY;
-			if (!last)
-				break;
-		case RXRPC_CALL_SERVER_SEND_REPLY:
-			call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
-			break;
-		default:
-			break;
+			opt = IPV6_PMTUDISC_DO;
+			kernel_setsockopt(conn->params.local->socket,
+					  SOL_IPV6, IPV6_MTU_DISCOVER,
+					  (char *)&opt, sizeof(opt));
 		}
-		write_unlock_bh(&call->state_lock);
-	}
-
-	_proto("Tx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
-
-	sp->need_resend = false;
-	sp->resend_at = jiffies + rxrpc_resend_timeout;
-	if (!test_and_set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags)) {
-		_debug("run timer");
-		call->resend_timer.expires = sp->resend_at;
-		add_timer(&call->resend_timer);
-	}
-
-	/* attempt to cancel the rx-ACK timer, deferring reply transmission if
-	 * we're ACK'ing the request phase of an incoming call */
-	ret = -EAGAIN;
-	if (try_to_del_timer_sync(&call->ack_timer) >= 0) {
-		/* the packet may be freed by rxrpc_process_call() before this
-		 * returns */
-		ret = rxrpc_send_data_packet(call->conn, skb);
-		_net("sent skb %p", skb);
-	} else {
-		_debug("failed to delete ACK timer");
-	}
-
-	if (ret < 0) {
-		_debug("need instant resend %d", ret);
-		sp->need_resend = true;
-		rxrpc_instant_resend(call);
+		break;
+#endif
 	}
 
-	_leave("");
-}
-
-/*
- * Convert a host-endian header into a network-endian header.
- */
-static void rxrpc_insert_header(struct sk_buff *skb)
-{
-	struct rxrpc_wire_header whdr;
-	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-
-	whdr.epoch	= htonl(sp->hdr.epoch);
-	whdr.cid	= htonl(sp->hdr.cid);
-	whdr.callNumber	= htonl(sp->hdr.callNumber);
-	whdr.seq	= htonl(sp->hdr.seq);
-	whdr.serial	= htonl(sp->hdr.serial);
-	whdr.type	= sp->hdr.type;
-	whdr.flags	= sp->hdr.flags;
-	whdr.userStatus	= sp->hdr.userStatus;
-	whdr.securityIndex = sp->hdr.securityIndex;
-	whdr._rsvd	= htons(sp->hdr._rsvd);
-	whdr.serviceId	= htons(sp->hdr.serviceId);
-
-	memcpy(skb->head, &whdr, sizeof(whdr));
+	up_write(&conn->params.local->defrag_sem);
+	goto done;
 }
 
 /*
- * send data through a socket
- * - must be called in process context
- * - caller holds the socket locked
+ * reject packets through the local endpoint
  */
-static int rxrpc_send_data(struct rxrpc_sock *rx,
-			   struct rxrpc_call *call,
-			   struct msghdr *msg, size_t len)
+void rxrpc_reject_packets(struct rxrpc_local *local)
 {
+	struct sockaddr_rxrpc srx;
 	struct rxrpc_skb_priv *sp;
+	struct rxrpc_wire_header whdr;
 	struct sk_buff *skb;
-	struct sock *sk = &rx->sk;
-	long timeo;
-	bool more;
-	int ret, copied;
-
-	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
-
-	/* this should be in poll */
-	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
-
-	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
-		return -EPIPE;
-
-	more = msg->msg_flags & MSG_MORE;
-
-	skb = call->tx_pending;
-	call->tx_pending = NULL;
-
-	copied = 0;
-	do {
-		if (!skb) {
-			size_t size, chunk, max, space;
-
-			_debug("alloc");
-
-			if (CIRC_SPACE(call->acks_head,
-				       ACCESS_ONCE(call->acks_tail),
-				       call->acks_winsz) <= 0) {
-				ret = -EAGAIN;
-				if (msg->msg_flags & MSG_DONTWAIT)
-					goto maybe_error;
-				ret = rxrpc_wait_for_tx_window(rx, call,
-							       &timeo);
-				if (ret < 0)
-					goto maybe_error;
-			}
-
-			max = call->conn->params.peer->maxdata;
-			max -= call->conn->security_size;
-			max &= ~(call->conn->size_align - 1UL);
-
-			chunk = max;
-			if (chunk > msg_data_left(msg) && !more)
-				chunk = msg_data_left(msg);
-
-			space = chunk + call->conn->size_align;
-			space &= ~(call->conn->size_align - 1UL);
-
-			size = space + call->conn->header_size;
-
-			_debug("SIZE: %zu/%zu/%zu", chunk, space, size);
-
-			/* create a buffer that we can retain until it's ACK'd */
-			skb = sock_alloc_send_skb(
-				sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
-			if (!skb)
-				goto maybe_error;
-
-			rxrpc_new_skb(skb);
-
-			_debug("ALLOC SEND %p", skb);
-
-			ASSERTCMP(skb->mark, ==, 0);
+	struct msghdr msg;
+	struct kvec iov[2];
+	size_t size;
+	__be32 code;
 
-			_debug("HS: %u", call->conn->header_size);
-			skb_reserve(skb, call->conn->header_size);
-			skb->len += call->conn->header_size;
+	_enter("%d", local->debug_id);
 
-			sp = rxrpc_skb(skb);
-			sp->remain = chunk;
-			if (sp->remain > skb_tailroom(skb))
-				sp->remain = skb_tailroom(skb);
+	iov[0].iov_base = &whdr;
+	iov[0].iov_len = sizeof(whdr);
+	iov[1].iov_base = &code;
+	iov[1].iov_len = sizeof(code);
+	size = sizeof(whdr) + sizeof(code);
 
-			_net("skb: hr %d, tr %d, hl %d, rm %d",
-			       skb_headroom(skb),
-			       skb_tailroom(skb),
-			       skb_headlen(skb),
-			       sp->remain);
+	msg.msg_name = &srx.transport;
+	msg.msg_control = NULL;
+	msg.msg_controllen = 0;
+	msg.msg_flags = 0;
 
-			skb->ip_summed = CHECKSUM_UNNECESSARY;
-		}
+	memset(&whdr, 0, sizeof(whdr));
+	whdr.type = RXRPC_PACKET_TYPE_ABORT;
 
-		_debug("append");
+	while ((skb = skb_dequeue(&local->reject_queue))) {
+		rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
 		sp = rxrpc_skb(skb);
 
-		/* append next segment of data to the current buffer */
-		if (msg_data_left(msg) > 0) {
-			int copy = skb_tailroom(skb);
-			ASSERTCMP(copy, >, 0);
-			if (copy > msg_data_left(msg))
-				copy = msg_data_left(msg);
-			if (copy > sp->remain)
-				copy = sp->remain;
-
-			_debug("add");
-			ret = skb_add_data(skb, &msg->msg_iter, copy);
-			_debug("added");
-			if (ret < 0)
-				goto efault;
-			sp->remain -= copy;
-			skb->mark += copy;
-			copied += copy;
-		}
+		if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
+			msg.msg_namelen = srx.transport_len;
 
-		/* check for the far side aborting the call or a network error
-		 * occurring */
-		if (call->state > RXRPC_CALL_COMPLETE)
-			goto call_aborted;
-
-		/* add the packet to the send queue if it's now full */
-		if (sp->remain <= 0 ||
-		    (msg_data_left(msg) == 0 && !more)) {
-			struct rxrpc_connection *conn = call->conn;
-			uint32_t seq;
-			size_t pad;
-
-			/* pad out if we're using security */
-			if (conn->security_ix) {
-				pad = conn->security_size + skb->mark;
-				pad = conn->size_align - pad;
-				pad &= conn->size_align - 1;
-				_debug("pad %zu", pad);
-				if (pad)
-					memset(skb_put(skb, pad), 0, pad);
-			}
-
-			seq = atomic_inc_return(&call->sequence);
-
-			sp->hdr.epoch	= conn->proto.epoch;
-			sp->hdr.cid	= call->cid;
-			sp->hdr.callNumber = call->call_id;
-			sp->hdr.seq	= seq;
-			sp->hdr.serial	= atomic_inc_return(&conn->serial);
-			sp->hdr.type	= RXRPC_PACKET_TYPE_DATA;
-			sp->hdr.userStatus = 0;
-			sp->hdr.securityIndex = conn->security_ix;
-			sp->hdr._rsvd	= 0;
-			sp->hdr.serviceId = call->service_id;
-
-			sp->hdr.flags = conn->out_clientflag;
-			if (msg_data_left(msg) == 0 && !more)
-				sp->hdr.flags |= RXRPC_LAST_PACKET;
-			else if (CIRC_SPACE(call->acks_head,
-					    ACCESS_ONCE(call->acks_tail),
-					    call->acks_winsz) > 1)
-				sp->hdr.flags |= RXRPC_MORE_PACKETS;
-			if (more && seq & 1)
-				sp->hdr.flags |= RXRPC_REQUEST_ACK;
-
-			ret = conn->security->secure_packet(
-				call, skb, skb->mark,
-				skb->head + sizeof(struct rxrpc_wire_header));
-			if (ret < 0)
-				goto out;
-
-			rxrpc_insert_header(skb);
-			rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
-			skb = NULL;
-		}
-	} while (msg_data_left(msg) > 0);
+			code = htonl(skb->priority);
 
-success:
-	ret = copied;
-out:
-	call->tx_pending = skb;
-	_leave(" = %d", ret);
-	return ret;
+			whdr.epoch	= htonl(sp->hdr.epoch);
+			whdr.cid	= htonl(sp->hdr.cid);
+			whdr.callNumber	= htonl(sp->hdr.callNumber);
+			whdr.serviceId	= htons(sp->hdr.serviceId);
+			whdr.flags	= sp->hdr.flags;
+			whdr.flags	^= RXRPC_CLIENT_INITIATED;
+			whdr.flags	&= RXRPC_CLIENT_INITIATED;
 
-call_aborted:
-	rxrpc_free_skb(skb);
-	if (call->state == RXRPC_CALL_NETWORK_ERROR)
-		ret = call->error_report < RXRPC_LOCAL_ERROR_OFFSET ?
-			call->error_report :
-			call->error_report - RXRPC_LOCAL_ERROR_OFFSET;
-	else
-		ret = -ECONNABORTED;
-	_leave(" = %d", ret);
-	return ret;
+			kernel_sendmsg(local->socket, &msg, iov, 2, size);
+		}
 
-maybe_error:
-	if (copied)
-		goto success;
-	goto out;
+		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
+	}
 
-efault:
-	ret = -EFAULT;
-	goto out;
+	_leave("");
 }