From: Mariusz Klimek <maklimek97@gmail.com>
To: netdev@vger.kernel.org
Cc: andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com,
kuba@kernel.org, pabeni@redhat.com, dsahern@kernel.org,
idosch@nvidia.com, ncardwell@google.com, shuah@kernel.org,
kuniyu@google.com, alice@isovalent.com,
Mariusz Klimek <maklimek97@gmail.com>
Subject: [PATCH net-next 01/10] ipv6: do not fragment packets into jumbograms
Date: Mon, 8 Jun 2026 15:07:46 +0200 [thread overview]
Message-ID: <20260608130755.5626-2-maklimek97@gmail.com> (raw)
In-Reply-To: <20260608130755.5626-1-maklimek97@gmail.com>
This patch prevents packets from being fragmented into jumbograms by
capping the effective MTU to IP6_MAX_MTU in ip6_fragment, as RFC2675
prohibits a Jumbo Payload option from being carried in a packet that
carries a fragment header.
Signed-off-by: Mariusz Klimek <maklimek97@gmail.com>
---
net/ipv6/ip6_output.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index c14adcdd4396..67c34fb281c6 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -935,6 +935,8 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
}
if (mtu < hlen + sizeof(struct frag_hdr) + 8)
goto fail_toobig;
+ else if (unlikely(mtu > IP6_MAX_MTU))
+ mtu = IP6_MAX_MTU;
mtu -= hlen + sizeof(struct frag_hdr);
frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,
--
2.47.3
next parent reply other threads:[~2026-06-08 13:08 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260608130755.5626-1-maklimek97@gmail.com>
2026-06-08 13:07 ` Mariusz Klimek [this message]
2026-06-08 13:07 ` [PATCH net-next 02/10] ipv6: allow route exceptions with MTUs above 65535 Mariusz Klimek
2026-06-08 13:07 ` [PATCH net-next 03/10] ipv6: add jumbo payload option to non-gso jumbograms Mariusz Klimek
2026-06-08 13:07 ` [PATCH net-next 04/10] tcp: decouple TSO segment length from MSS Mariusz Klimek
2026-06-08 13:07 ` [PATCH net-next 05/10] tcp: split jumbograms with urgent pointer correctly Mariusz Klimek
2026-06-08 13:07 ` [PATCH net-next 06/10] tcp: set MSS correctly for PMTU above 65535 Mariusz Klimek
2026-06-08 13:07 ` [PATCH net-next 07/10] veth: raise the max MTU " Mariusz Klimek
2026-06-08 13:07 ` [PATCH net-next 08/10] selftests/net: test sending TCP jumbograms over veth Mariusz Klimek
2026-06-08 13:07 ` [PATCH net-next 09/10] selftests/net: add test cases with MTU above 65535 to big_tcp.sh Mariusz Klimek
2026-06-08 13:07 ` [PATCH net-next 10/10] selftests/net: add jumbogram test case to msg_zerocopy.sh Mariusz Klimek
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