rxrpc: Keep the skb private record of the Rx header in host byte order

Currently, a copy of the Rx packet header is copied into the the sk_buff
private data so that we can advance the pointer into the buffer,
potentially discarding the original.  At the moment, this copy is held in
network byte order, but this means we're doing a lot of unnecessary
translations.

The reasons it was done this way are that we need the values in network
byte order occasionally and we can use the copy, slightly modified, as part
of an iov array when sending an ack or an abort packet.

However, it seems more reasonable on review that it would be better kept in
host byte order and that we make up a new header when we want to send
another packet.

To this end, rename the original header struct to rxrpc_wire_header (with
BE fields) and institute a variant called rxrpc_host_header that has host
order fields.  Change the struct in the sk_buff private data into an
rxrpc_host_header and translate the values when filling it in.

This further allows us to keep values kept in various structures in host
byte order rather than network byte order and allows removal of some fields
that are byteswapped duplicates.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 51 insertions, 57 deletions

diff --git a/net/rxrpc/ar-ack.c b/net/rxrpc/ar-ack.c
index 9183da740600..20f3f001694e 100644
--- a/net/rxrpc/ar-ack.c
+++ b/net/rxrpc/ar-ack.c
@@ -91,7 +91,7 @@ static const s8 rxrpc_ack_priority[] = {
  * propose an ACK be sent
  */
 void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
-			 __be32 serial, bool immediate)
+			 u32 serial, bool immediate)
 {
 	unsigned long expiry;
 	s8 prior = rxrpc_ack_priority[ack_reason];
@@ -99,8 +99,7 @@ void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
 	ASSERTCMP(prior, >, 0);
 
 	_enter("{%d},%s,%%%x,%u",
-	       call->debug_id, rxrpc_acks(ack_reason), ntohl(serial),
-	       immediate);
+	       call->debug_id, rxrpc_acks(ack_reason), serial, immediate);
 
 	if (prior < rxrpc_ack_priority[call->ackr_reason]) {
 		if (immediate)
@@ -139,7 +138,7 @@ void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
 		expiry = rxrpc_requested_ack_delay;
 		if (!expiry)
 			goto cancel_timer;
-		if (!immediate || serial == cpu_to_be32(1)) {
+		if (!immediate || serial == 1) {
 			_debug("run defer timer");
 			goto run_timer;
 		}
@@ -157,7 +156,7 @@ run_timer:
 	return;
 
 cancel_timer:
-	_debug("cancel timer %%%u", ntohl(serial));
+	_debug("cancel timer %%%u", serial);
 	try_to_del_timer_sync(&call->ack_timer);
 	read_lock_bh(&call->state_lock);
 	if (call->state <= RXRPC_CALL_COMPLETE &&
@@ -170,7 +169,7 @@ cancel_timer:
  * propose an ACK be sent, locking the call structure
  */
 void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
-		       __be32 serial, bool immediate)
+		       u32 serial, bool immediate)
 {
 	s8 prior = rxrpc_ack_priority[ack_reason];
 
@@ -214,8 +213,8 @@ static void rxrpc_set_resend(struct rxrpc_call *call, u8 resend,
  */
 static void rxrpc_resend(struct rxrpc_call *call)
 {
+	struct rxrpc_wire_header *whdr;
 	struct rxrpc_skb_priv *sp;
-	struct rxrpc_header *hdr;
 	struct sk_buff *txb;
 	unsigned long *p_txb, resend_at;
 	bool stop;
@@ -247,14 +246,13 @@ static void rxrpc_resend(struct rxrpc_call *call)
 			sp->need_resend = false;
 
 			/* each Tx packet has a new serial number */
-			sp->hdr.serial =
-				htonl(atomic_inc_return(&call->conn->serial));
+			sp->hdr.serial = atomic_inc_return(&call->conn->serial);
 
-			hdr = (struct rxrpc_header *) txb->head;
-			hdr->serial = sp->hdr.serial;
+			whdr = (struct rxrpc_wire_header *)txb->head;
+			whdr->serial = htonl(sp->hdr.serial);
 
 			_proto("Tx DATA %%%u { #%d }",
-			       ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
+			       sp->hdr.serial, sp->hdr.seq);
 			if (rxrpc_send_packet(call->conn->trans, txb) < 0) {
 				stop = true;
 				sp->resend_at = jiffies + 3;
@@ -428,7 +426,7 @@ static void rxrpc_rotate_tx_window(struct rxrpc_call *call, u32 hard)
 	int tail = call->acks_tail, old_tail;
 	int win = CIRC_CNT(call->acks_head, tail, call->acks_winsz);
 
-	_enter("{%u,%u},%u", call->acks_hard, win, hard);
+	kenter("{%u,%u},%u", call->acks_hard, win, hard);
 
 	ASSERTCMP(hard - call->acks_hard, <=, win);
 
@@ -478,11 +476,11 @@ static int rxrpc_drain_rx_oos_queue(struct rxrpc_call *call)
 		sp = rxrpc_skb(skb);
 
 		_debug("drain OOS packet %d [%d]",
-		       ntohl(sp->hdr.seq), call->rx_first_oos);
+		       sp->hdr.seq, call->rx_first_oos);
 
-		if (ntohl(sp->hdr.seq) != call->rx_first_oos) {
+		if (sp->hdr.seq != call->rx_first_oos) {
 			skb_queue_head(&call->rx_oos_queue, skb);
-			call->rx_first_oos = ntohl(rxrpc_skb(skb)->hdr.seq);
+			call->rx_first_oos = rxrpc_skb(skb)->hdr.seq;
 			_debug("requeue %p {%u}", skb, call->rx_first_oos);
 		} else {
 			skb->mark = RXRPC_SKB_MARK_DATA;
@@ -496,8 +494,7 @@ static int rxrpc_drain_rx_oos_queue(struct rxrpc_call *call)
 			/* find out what the next packet is */
 			skb = skb_peek(&call->rx_oos_queue);
 			if (skb)
-				call->rx_first_oos =
-					ntohl(rxrpc_skb(skb)->hdr.seq);
+				call->rx_first_oos = rxrpc_skb(skb)->hdr.seq;
 			else
 				call->rx_first_oos = 0;
 			_debug("peek %p {%u}", skb, call->rx_first_oos);
@@ -522,7 +519,7 @@ static void rxrpc_insert_oos_packet(struct rxrpc_call *call,
 	u32 seq;
 
 	sp = rxrpc_skb(skb);
-	seq = ntohl(sp->hdr.seq);
+	seq = sp->hdr.seq;
 	_enter(",,{%u}", seq);
 
 	skb->destructor = rxrpc_packet_destructor;
@@ -535,9 +532,8 @@ static void rxrpc_insert_oos_packet(struct rxrpc_call *call,
 
 	skb_queue_walk(&call->rx_oos_queue, p) {
 		psp = rxrpc_skb(p);
-		if (ntohl(psp->hdr.seq) > seq) {
-			_debug("insert oos #%u before #%u",
-			       seq, ntohl(psp->hdr.seq));
+		if (psp->hdr.seq > seq) {
+			_debug("insert oos #%u before #%u", seq, psp->hdr.seq);
 			skb_insert(p, skb, &call->rx_oos_queue);
 			goto inserted;
 		}
@@ -586,7 +582,7 @@ static void rxrpc_zap_tx_window(struct rxrpc_call *call)
 
 		skb = (struct sk_buff *) _skb;
 		sp = rxrpc_skb(skb);
-		_debug("+++ clear Tx %u", ntohl(sp->hdr.seq));
+		_debug("+++ clear Tx %u", sp->hdr.seq);
 		rxrpc_free_skb(skb);
 	}
 
@@ -657,8 +653,7 @@ process_further:
 		/* data packets that wind up here have been received out of
 		 * order, need security processing or are jumbo packets */
 	case RXRPC_PACKET_TYPE_DATA:
-		_proto("OOSQ DATA %%%u { #%u }",
-		       ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
+		_proto("OOSQ DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
 
 		/* secured packets must be verified and possibly decrypted */
 		if (rxrpc_verify_packet(call, skb, _abort_code) < 0)
@@ -676,7 +671,7 @@ process_further:
 		if (!skb_pull(skb, sizeof(ack)))
 			BUG();
 
-		latest = ntohl(sp->hdr.serial);
+		latest = sp->hdr.serial;
 		hard = ntohl(ack.firstPacket);
 		tx = atomic_read(&call->sequence);
 
@@ -881,9 +876,9 @@ void rxrpc_process_call(struct work_struct *work)
 {
 	struct rxrpc_call *call =
 		container_of(work, struct rxrpc_call, processor);
+	struct rxrpc_wire_header whdr;
 	struct rxrpc_ackpacket ack;
 	struct rxrpc_ackinfo ackinfo;
-	struct rxrpc_header hdr;
 	struct msghdr msg;
 	struct kvec iov[5];
 	enum rxrpc_call_event genbit;
@@ -891,7 +886,7 @@ void rxrpc_process_call(struct work_struct *work)
 	__be32 data, pad;
 	size_t len;
 	int loop, nbit, ioc, ret, mtu;
-	u32 abort_code = RX_PROTOCOL_ERROR;
+	u32 serial, abort_code = RX_PROTOCOL_ERROR;
 	u8 *acks = NULL;
 
 	//printk("\n--------------------\n");
@@ -912,20 +907,20 @@ void rxrpc_process_call(struct work_struct *work)
 	msg.msg_controllen = 0;
 	msg.msg_flags	= 0;
 
-	hdr.epoch	= call->conn->epoch;
-	hdr.cid		= call->cid;
-	hdr.callNumber	= call->call_id;
-	hdr.seq		= 0;
-	hdr.type	= RXRPC_PACKET_TYPE_ACK;
-	hdr.flags	= call->conn->out_clientflag;
-	hdr.userStatus	= 0;
-	hdr.securityIndex = call->conn->security_ix;
-	hdr._rsvd	= 0;
-	hdr.serviceId	= call->conn->service_id;
+	whdr.epoch	= htonl(call->conn->epoch);
+	whdr.cid	= htonl(call->cid);
+	whdr.callNumber	= htonl(call->call_id);
+	whdr.seq	= 0;
+	whdr.type	= RXRPC_PACKET_TYPE_ACK;
+	whdr.flags	= call->conn->out_clientflag;
+	whdr.userStatus	= 0;
+	whdr.securityIndex = call->conn->security_ix;
+	whdr._rsvd	= 0;
+	whdr.serviceId	= htons(call->service_id);
 
 	memset(iov, 0, sizeof(iov));
-	iov[0].iov_base	= &hdr;
-	iov[0].iov_len	= sizeof(hdr);
+	iov[0].iov_base	= &whdr;
+	iov[0].iov_len	= sizeof(whdr);
 
 	/* deal with events of a final nature */
 	if (test_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
@@ -966,7 +961,7 @@ void rxrpc_process_call(struct work_struct *work)
 	}
 
 	if (test_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events)) {
-		hdr.type = RXRPC_PACKET_TYPE_BUSY;
+		whdr.type = RXRPC_PACKET_TYPE_BUSY;
 		genbit = RXRPC_CALL_EV_REJECT_BUSY;
 		goto send_message;
 	}
@@ -977,7 +972,7 @@ void rxrpc_process_call(struct work_struct *work)
 		if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 				       ECONNABORTED, true) < 0)
 			goto no_mem;
-		hdr.type = RXRPC_PACKET_TYPE_ABORT;
+		whdr.type = RXRPC_PACKET_TYPE_ABORT;
 		data = htonl(call->abort_code);
 		iov[1].iov_base = &data;
 		iov[1].iov_len = sizeof(data);
@@ -996,9 +991,9 @@ void rxrpc_process_call(struct work_struct *work)
 		call->ackr_reason = 0;
 
 		spin_lock_bh(&call->lock);
-		ack.serial = call->ackr_serial;
-		ack.previousPacket = call->ackr_prev_seq;
-		ack.firstPacket = htonl(call->rx_data_eaten + 1);
+		ack.serial	= htonl(call->ackr_serial);
+		ack.previousPacket = htonl(call->ackr_prev_seq);
+		ack.firstPacket	= htonl(call->rx_data_eaten + 1);
 		spin_unlock_bh(&call->lock);
 
 		pad = 0;
@@ -1100,13 +1095,11 @@ void rxrpc_process_call(struct work_struct *work)
 		//hdr.flags	= RXRPC_SLOW_START_OK;
 		ack.bufferSpace	= htons(8);
 		ack.maxSkew	= 0;
-		ack.serial	= 0;
-		ack.reason	= 0;
 
 		spin_lock_bh(&call->lock);
-		ack.reason = call->ackr_reason;
-		ack.serial = call->ackr_serial;
-		ack.previousPacket = call->ackr_prev_seq;
+		ack.reason	= call->ackr_reason;
+		ack.serial	= htonl(call->ackr_serial);
+		ack.previousPacket = htonl(call->ackr_prev_seq);
 		ack.firstPacket = htonl(call->rx_data_eaten + 1);
 
 		ack.nAcks = 0;
@@ -1225,9 +1218,10 @@ send_ACK:
 	ackinfo.rxMTU	= htonl(rxrpc_rx_mtu);
 	ackinfo.jumbo_max = htonl(rxrpc_rx_jumbo_max);
 
-	hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
+	serial = atomic_inc_return(&call->conn->serial);
+	whdr.serial = htonl(serial);
 	_proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
-	       ntohl(hdr.serial),
+	       serial,
 	       ntohs(ack.maxSkew),
 	       ntohl(ack.firstPacket),
 	       ntohl(ack.previousPacket),
@@ -1243,8 +1237,9 @@ send_ACK:
 send_message:
 	_debug("send message");
 
-	hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
-	_proto("Tx %s %%%u", rxrpc_pkts[hdr.type], ntohl(hdr.serial));
+	serial = atomic_inc_return(&call->conn->serial);
+	whdr.serial = htonl(serial);
+	_proto("Tx %s %%%u", rxrpc_pkts[whdr.type], serial);
 send_message_2:
 
 	len = iov[0].iov_len;
@@ -1327,8 +1322,7 @@ maybe_reschedule:
 	if (call->state >= RXRPC_CALL_COMPLETE &&
 	    !list_empty(&call->accept_link)) {
 		_debug("X unlinking once-pending call %p { e=%lx f=%lx c=%x }",
-		       call, call->events, call->flags,
-		       ntohl(call->conn->cid));
+		       call, call->events, call->flags, call->conn->cid);
 
 		read_lock_bh(&call->state_lock);
 		if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
@@ -1346,7 +1340,7 @@ error:
 	 * this means there's a race between clearing the flag and setting the
 	 * work pending bit and the work item being processed again */
 	if (call->events && !work_pending(&call->processor)) {
-		_debug("jumpstart %x", ntohl(call->conn->cid));
+		_debug("jumpstart %x", call->conn->cid);
 		rxrpc_queue_call(call);
 	}