netpoll causes malformed protocol message

netpoll causes malformed protocol message

[Stephen Hemminger]

Now that I know what this is, perhaps others should know.

> Linus Torvalds <torvalds@osdl.org> wrote:
>   
> > 
> > Since I've been re-testing the Apple Intel Mac Mini suspend/resume due to 
> > a USB problem, I thought I might as well see if this rings any bells..
> > 
> > On resume, networking does actually eventually work, but it takes a while 
> > before it gets going. The dmesg for the resume shows:
> > 
> > 	sky2 eth0: Link is up at 100 Mbps, full duplex, flow control both
> > 	protocol 0000 is buggy, dev eth0
> > 	protocol 0000 is buggy, dev eth0  
> 
> 


The packets created by netpoll trigger the check for bogus protocol
in net/core/dev.c if it gets busy enough to actually use the netpoll
tx queue.

I'll whip a fix, the skb should be setup better and it shouldn't call
different xmit paths for the queued/non-queued case. Follow on patch
to replace the roll your own skb queue's with the already there sk_buff_head
routines. Given the normal case is lots of small writes, probably
better to just have a character queue to cause coalescing.

The netpoll code is a step child it looks like and ignores using
standard code when it should.

[RFT] netpoll: fully initialize skb

[Stephen Hemminger]

This stops the 
	protocol 0000 is buggy, dev eth0
messages from occurring when netpoll decides to queue packets.
It fully initializes the protocol fields.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>

If you want to wait on including it, I intend to rollup all the netpoll
patches into a patchbomb tomorrow.

--- netpoll.orig/net/core/netpoll.c
+++ netpoll/net/core/netpoll.c
@@ -335,13 +335,13 @@ void netpoll_send_udp(struct netpoll *np
 	memcpy(skb->data, msg, len);
 	skb->len += len;
 
-	udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
+	skb->h.uh = udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
 	udph->source = htons(np->local_port);
 	udph->dest = htons(np->remote_port);
 	udph->len = htons(udp_len);
 	udph->check = 0;
 
-	iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
+	skb->nh.iph = iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
 
 	/* iph->version = 4; iph->ihl = 5; */
 	put_unaligned(0x45, (unsigned char *)iph);
@@ -357,8 +357,8 @@ void netpoll_send_udp(struct netpoll *np
 	iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);
 
 	eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
-
-	eth->h_proto = htons(ETH_P_IP);
+	skb->mac.raw = skb->data;
+	skb->protocol = eth->h_proto = htons(ETH_P_IP);
 	memcpy(eth->h_source, np->local_mac, 6);
 	memcpy(eth->h_dest, np->remote_mac, 6);