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ip6_gre: Make o_seqno start from 0 in native mode

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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: c12b395a46 ("gre: Support GRE over IPv6")
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Acked-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Peilin Ye 2022-04-21 15:08:38 -07:00 committed by David S. Miller
parent ff827beb70
commit fde98ae91f
1 changed files with 5 additions and 6 deletions
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11
net/ipv6/ip6_gre.c
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@ -724,6 +724,7 @@ 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;
@ -739,7 +740,6 @@ 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_txcheck(skb);
@ -770,15 +770,14 @@ 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,