From 38502af77e07b5d6650b9ff99a0b482d86366592 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Mon, 25 Mar 2013 20:19:56 +0000 Subject: [PATCH] tuntap: set transport header before passing it to kernel Currently, for the packets receives from tuntap, before doing header check, kernel just reset the transport header in netif_receive_skb() which pretends no l4 header. This is suboptimal for precise packet length estimation (introduced in 1def9238) which needs correct l4 header for gso packets. So this patch set the transport header to csum_start for partial checksum packets, otherwise it first try skb_flow_dissect(), if it fails, just reset the transport header. Cc: Eric Dumazet Signed-off-by: Jason Wang Signed-off-by: David S. Miller --- drivers/net/tun.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 95837c1b197a..48cd73a2dc55 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -70,6 +70,7 @@ #include #include +#include /* Uncomment to enable debugging */ /* #define TUN_DEBUG 1 */ @@ -1049,6 +1050,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, bool zerocopy = false; int err; u32 rxhash; + struct flow_keys keys; if (!(tun->flags & TUN_NO_PI)) { if ((len -= sizeof(pi)) > total_len) @@ -1203,6 +1205,14 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, } skb_reset_network_header(skb); + + if (skb->ip_summed == CHECKSUM_PARTIAL) + skb_set_transport_header(skb, skb_checksum_start_offset(skb)); + else if (skb_flow_dissect(skb, &keys)) + skb_set_transport_header(skb, keys.thoff); + else + skb_reset_transport_header(skb); + rxhash = skb_get_rxhash(skb); netif_rx_ni(skb);