From 8fb58f1ecf5cbcc7805dd339243b7d9837cbabbe Mon Sep 17 00:00:00 2001 From: "Nikita V. Shirokov" Date: Tue, 17 Apr 2018 21:42:19 -0700 Subject: [PATCH] bpf: make tun compatible w/ bpf_xdp_adjust_tail w/ bpf_xdp_adjust_tail helper xdp's data_end pointer could be changed as well (only "decrease" of pointer's location is going to be supported). changing of this pointer will change packet's size. for tun driver we need to adjust XDP_PASS handling by recalculating length of the packet if it was passed to the TCP/IP stack (in case if after xdp's prog run data_end pointer was adjusted) Reviewed-by: Jason Wang Signed-off-by: Nikita V. Shirokov Acked-by: Michael S. Tsirkin Signed-off-by: Daniel Borkmann --- drivers/net/tun.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 1e58be152d5c..901351a6ed21 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1696,6 +1696,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, return NULL; case XDP_PASS: delta = orig_data - xdp.data; + len = xdp.data_end - xdp.data; break; default: bpf_warn_invalid_xdp_action(act); @@ -1716,7 +1717,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, } skb_reserve(skb, pad - delta); - skb_put(skb, len + delta); + skb_put(skb, len); get_page(alloc_frag->page); alloc_frag->offset += buflen; -- 2.30.2