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Commit 0eb3ec0a authored by Peilin Ye's avatar Peilin Ye Committed by Greg Kroah-Hartman
Browse files

ip6_gre: Make o_seqno start from 0 in native mode 



[ Upstream commit fde98ae91f79cab4e020f40c35ed23cbdc59661c ]

For IP6GRE and IP6GRETAP devices, currently o_seqno starts from 1 in
native mode.  According to RFC 2890 2.2., "The first datagram is sent
with a sequence number of 0."  Fix it.

It is worth mentioning that o_seqno already starts from 0 in collect_md
mode, see the "if (tunnel->parms.collect_md)" clause in __gre6_xmit(),
where tunnel->o_seqno is passed to gre_build_header() before getting
incremented.

Fixes: c12b395a ("gre: Support GRE over IPv6")
Signed-off-by: default avatarPeilin Ye <peilin.ye@bytedance.com>
Acked-by: default avatarWilliam Tu <u9012063@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Stable-dep-of: d80fc101d2eb ("erspan: get the proto with the md version for collect_md")
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 30409624

net/ipv6/ip6_gre.c

+5 −6
Original line number Diff line number Diff line
@@ -711,6 +711,7 @@ static netdev_tx_t __gre6_xmit(struct sk_buff *skb, 
{

	struct ip6_tnl *tunnel = netdev_priv(dev);

	__be16 protocol;

	__be16 flags;



	if (dev->type == ARPHRD_ETHER)

		IPCB(skb)->flags = 0;
@@ -726,7 +727,6 @@ static netdev_tx_t __gre6_xmit(struct sk_buff *skb, 
	if (tunnel->parms.collect_md) {

		struct ip_tunnel_info *tun_info;

		const struct ip_tunnel_key *key;

		__be16 flags;

		int tun_hlen;



		tun_info = skb_tunnel_info(skb);
@@ -758,15 +758,14 @@ static netdev_tx_t __gre6_xmit(struct sk_buff *skb, 
						      : 0);



	} else {

		if (tunnel->parms.o_flags & TUNNEL_SEQ)

			tunnel->o_seqno++;



		if (skb_cow_head(skb, dev->needed_headroom ?: tunnel->hlen))

			return -ENOMEM;



		gre_build_header(skb, tunnel->tun_hlen, tunnel->parms.o_flags,

		flags = tunnel->parms.o_flags;



		gre_build_header(skb, tunnel->tun_hlen, flags,

				 protocol, tunnel->parms.o_key,

				 htonl(tunnel->o_seqno));

				 (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0);

	}



	return ip6_tnl_xmit(skb, dev, dsfield, fl6, encap_limit, pmtu,