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, 18 insertions, 11 deletions

diff --git a/net/rxrpc/ar-local.c b/net/rxrpc/ar-local.c
index 78483b4602bf..4e1e6db0050b 100644
--- a/net/rxrpc/ar-local.c
+++ b/net/rxrpc/ar-local.c
@@ -323,9 +323,11 @@ void __exit rxrpc_destroy_all_locals(void)
  * Reply to a version request
  */
 static void rxrpc_send_version_request(struct rxrpc_local *local,
-				       struct rxrpc_header *hdr,
+				       struct rxrpc_host_header *hdr,
 				       struct sk_buff *skb)
 {
+	struct rxrpc_wire_header whdr;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	struct sockaddr_in sin;
 	struct msghdr msg;
 	struct kvec iov[2];
@@ -344,15 +346,20 @@ static void rxrpc_send_version_request(struct rxrpc_local *local,
 	msg.msg_controllen = 0;
 	msg.msg_flags	= 0;
 
-	hdr->seq	= 0;
-	hdr->serial	= 0;
-	hdr->type	= RXRPC_PACKET_TYPE_VERSION;
-	hdr->flags	= RXRPC_LAST_PACKET | (~hdr->flags & RXRPC_CLIENT_INITIATED);
-	hdr->userStatus	= 0;
-	hdr->_rsvd	= 0;
-
-	iov[0].iov_base	= hdr;
-	iov[0].iov_len	= sizeof(*hdr);
+	whdr.epoch	= htonl(sp->hdr.epoch);
+	whdr.cid	= htonl(sp->hdr.cid);
+	whdr.callNumber	= htonl(sp->hdr.callNumber);
+	whdr.seq	= 0;
+	whdr.serial	= 0;
+	whdr.type	= RXRPC_PACKET_TYPE_VERSION;
+	whdr.flags	= RXRPC_LAST_PACKET | (~hdr->flags & RXRPC_CLIENT_INITIATED);
+	whdr.userStatus	= 0;
+	whdr.securityIndex = 0;
+	whdr._rsvd	= 0;
+	whdr.serviceId	= htons(sp->hdr.serviceId);
+
+	iov[0].iov_base	= &whdr;
+	iov[0].iov_len	= sizeof(whdr);
 	iov[1].iov_base	= (char *)rxrpc_version_string;
 	iov[1].iov_len	= sizeof(rxrpc_version_string);
 
@@ -383,7 +390,7 @@ static void rxrpc_process_local_events(struct work_struct *work)
 	while ((skb = skb_dequeue(&local->event_queue))) {
 		struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 
-		kdebug("{%d},{%u}", local->debug_id, sp->hdr.type);
+		_debug("{%d},{%u}", local->debug_id, sp->hdr.type);
 
 		switch (sp->hdr.type) {
 		case RXRPC_PACKET_TYPE_VERSION: