Re: [PATCH] xen-netfront: reset skb transport header before checksum
From: Eric Dumazet <hidden>
Date: 2015-05-12 01:51:35
On Mon, 2015-05-11 at 18:34 -0700, Venkat Venkatsubra wrote:
quoted hunk ↗ jump to hunk
In ed1f50c3a ("net: add skb_checksum_setup") some checksum functions were introduced in core. Subsequent change b5cf66cd1 ("xen-netfront: use new skb_checksum_setup function") made use of those functions to replace its own implementation. With that change ip_hdr() and tcp_hdr() were not pointing at the right place. d554f73df ("xen-netfront: reset skb network header before checksum") fixed the ip_hdr(). This patch fixes tcp_hdr(). We saw this problem when LRO was enabled on the host and it results in netfront setting skb->ip_summed to CHECKSUM_UNNECESSARY. Signed-off-by: Venkat Venkatsubra <redacted> --- drivers/net/xen-netfront.c | 1 + 1 file changed, 1 insertion(+)diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 3f45afd..ed5c242 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c@@ -889,6 +889,7 @@ static int handle_incoming_queue(struct netfront_queue *queue, /* Ethernet work: Delayed to here as it peeks the header. */ skb->protocol = eth_type_trans(skb, queue->info->netdev); skb_reset_network_header(skb); + skb_set_transport_header(skb, ip_hdrlen(skb)); if (checksum_setup(queue->info->netdev, skb)) { kfree_skb(skb);
This looks bogus for IPv6. I would rather fix skb_checksum_setup_ip() and skb_checksum_setup_ipv6(), since you already use correctly skb_maybe_pull_tail() there. In general, setting network and transport header at this point seems extra work.