From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Zhixing Chen <running910@gmail.com>
Cc: Harald Welte <laforge@gnumonks.org>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S . Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
osmocom-net-gprs@lists.osmocom.org, netdev@vger.kernel.org
Subject: Re: [PATCH net v2] gtp: parse extension headers before reading inner protocol
Date: Fri, 3 Jul 2026 13:38:36 +0200 [thread overview]
Message-ID: <akefPJ5cCrsZcpRw@chamomile> (raw)
In-Reply-To: <20260703093708.18141-1-running910@gmail.com>
On Fri, Jul 03, 2026 at 05:37:08PM +0800, Zhixing Chen wrote:
> GTPv1-U packets may carry a chain of extension headers before the inner
> IP packet. The receive path already parses and skips these extension
> headers, but it currently reads the inner protocol before doing so.
>
> As a result, the first extension header byte is interpreted as the inner
> IP version. Packets with extension headers are then dropped before PDP
> lookup.
>
> Parse the extension header chain before calling gtp_inner_proto(), so the
> inner protocol is read from the actual inner IP header.
>
> Fixes: c75fc0b9e5be ("gtp: identify tunnel via GTP device + GTP version + TEID + family")
> Signed-off-by: Zhixing Chen <running910@gmail.com>
Reviewed-by: Pablo Neira Ayuso <pablo@netfilter.org>
prev parent reply other threads:[~2026-07-03 11:38 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-03 9:37 [PATCH net v2] gtp: parse extension headers before reading inner protocol Zhixing Chen
2026-07-03 11:38 ` Pablo Neira Ayuso [this message]
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