diff mbox series

[net,2/3] ip6_gre: Make o_seqno start from 0 in native mode

Message ID 950bfd124e4f87bd9e1acbf6303545875c3681fe.1650575919.git.peilin.ye@bytedance.com (mailing list archive)
State Accepted
Commit fde98ae91f79cab4e020f40c35ed23cbdc59661c
Delegated to: Netdev Maintainers
Headers show
Series ip_gre, ip6_gre: o_seqno fixes | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 16 of 16 maintainers
netdev/build_clang success Errors and warnings before: 2 this patch: 2
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: line length of 86 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Peilin Ye April 21, 2022, 10:08 p.m. UTC 
From: Peilin Ye <peilin.ye@bytedance.com>

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: c12b395a4664 ("gre: Support GRE over IPv6")
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
---
 net/ipv6/ip6_gre.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

Comments

William Tu April 22, 2022, 4:25 p.m. UTC | #1 
On Thu, Apr 21, 2022 at 3:08 PM Peilin Ye <yepeilin.cs@gmail.com> wrote:
>
> From: Peilin Ye <peilin.ye@bytedance.com>
>
> 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: c12b395a4664 ("gre: Support GRE over IPv6")
> Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>

LGTM
Acked-by: William Tu <u9012063@gmail.com>
diff mbox series

Patch

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 976236736146..d9e4ac94eab4 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -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,