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[152.2.130.143]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-67a462a2e74sm3315307d50.18.2026.10.26.05.57.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Oct 2026 05:57:05 -0700 (PDT) From: Hengyu Liang To: gnault@redhat.com Cc: netdev@vger.kernel.org, davem@davemloft.net, edumazet@kernel.org, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, jchapman@katalix.com, tparkin@katalix.com Subject: Re: [PATCH net] l2tp: only return sessions of the given tunnel in l2tp_session_get() Date: Mon, 26 Oct 2026 08:57:02 -0400 Message-ID: <20261026125702.3101778-1-hengyul@cs.unc.edu> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi Guillaume, Thanks for looking at this. I wasn't sure about the intended semantics. l2tp.rst says "L2TPv3 session ids are unique across all tunnels", but it also says Linux allows the same ID in different tunnels, told apart by sk, and l2tp_session_register() still allows that for UDP encap. The patch only changes callers of l2tp_session_get() that pass a tunnel_id, and the result differs from v6.8: - pppol2tp_connect() for session 5 in tunnel 2 fails with EEXIST if tunnel 1 (another UDP socket) already has a connected session 5. - "ip l2tp del session tunnel_id 4 session_id 7" deletes tunnel 3's session 7 when only tunnel 3 has it. On v6.8 it fails. l2tp.rst describes CONN_ID there as the parent tunnel of the session. Am I misreading the documentation, is the documentation out of date, or is this behaviour not intended? Thanks, Hengyu