diff mbox series

[net,1/3] ip_gre: Make o_seqno start from 0 in native mode

Message ID dd63f881729052aa4e08a5c7cb9732724c557dfd.1650575919.git.peilin.ye@bytedance.com (mailing list archive)
State Accepted
Commit ff827beb706ed719c766acf36449801ded0c17fc
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: 30 this patch: 30
netdev/cc_maintainers success CCed 15 of 15 maintainers
netdev/build_clang success Errors and warnings before: 12 this patch: 12
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: 28 this patch: 28
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 17 lines checked
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, 10:07 p.m. UTC 
From: Peilin Ye <peilin.ye@bytedance.com>

For GRE and GRETAP 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 gre_fb_xmit(), where tunnel->o_seqno is passed to
gre_build_header() before getting incremented.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
---
 net/ipv4/ip_gre.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 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 GRE and GRETAP 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 gre_fb_xmit(), where tunnel->o_seqno is passed to
> gre_build_header() before getting incremented.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> 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/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 99db2e41ed10..ca70b92e80d9 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -459,14 +459,12 @@  static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
 		       __be16 proto)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
-
-	if (tunnel->parms.o_flags & TUNNEL_SEQ)
-		tunnel->o_seqno++;
+	__be16 flags = tunnel->parms.o_flags;
 
 	/* Push GRE header. */
 	gre_build_header(skb, tunnel->tun_hlen,
-			 tunnel->parms.o_flags, proto, tunnel->parms.o_key,
-			 htonl(tunnel->o_seqno));
+			 flags, proto, tunnel->parms.o_key,
+			 (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0);
 
 	ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol);
 }