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[34.85.134.180]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-65009200901sm4033085d50.1.2026.03.30.06.42.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Mar 2026 06:42:26 -0700 (PDT) Date: Mon, 30 Mar 2026 09:42:26 -0400 From: Willem de Bruijn To: Jakub Kicinski , bpf@vger.kernel.org Cc: netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, Jakub Kicinski , maze@google.com, willemdebruijn.kernel@gmail.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org Message-ID: In-Reply-To: <20260329180428.2657785-1-kuba@kernel.org> References: <20260329180428.2657785-1-kuba@kernel.org> Subject: Re: [PATCH bpf-next v2 1/2] net: clear the dst when performing encap / decap Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Jakub Kicinski wrote: > Commit ba9db6f907ac ("net: clear the dst when changing skb protocol") > added dst clearing when a BPF program changes the skb protocol > (e.g. IPv4 to IPv6). Since that was a fix we only cleared the dst when > the L3 protocol actually changes to keep it minimal. As suggested during > the discussion (see Link) encap or decap operation which wraps or unwraps > a same-protocol header may also render the existing dst incorrect - even > if that doesn't result in a crash, just the wrong route for the now-outermost > IP dst. > > Make dropping dst unconditional for bpf_skb_change_proto() and all > L3 encap / decap ops. > > Link: https://lore.kernel.org/CANP3RGfRaYwve_xgxH6Tp2zenzKn2-DjZ9tg023WVzfdJF3p_w@mail.gmail.com > Signed-off-by: Jakub Kicinski Reviewed-by: Willem de Bruijn