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[109.236.14.10]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-cc75f3d5794sm1741392a12.14.2026.09.23.18.15.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Sep 2026 18:16:01 -0700 (PDT) Sender: Yuyang Huang From: Yuyang Huang To: Yuyang Huang Cc: Aleksandr Loktionov , Andrew Lunn , "David S. Miller" , David Ahern , Donald Hunter , Eric Dumazet , Ido Schimmel , Jacob Keller , Jakub Kicinski , Kuniyuki Iwashima , Nicolas Dichtel , Nikolaos Gkarlis , Paolo Abeni , Sabrina Dubroca , Shuah Khan , Simon Horman , Stanislav Fomichev , Willem de Bruijn , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH net-next v7 0/5] rtnetlink: dump link-layer multicast addresses Date: Thu, 24 Sep 2026 10:15:49 +0900 Message-ID: <20260924011554.3494-1-sigefriedhyy@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit "ip maddr show" prints link-layer, IPv4 and IPv6 entries. The IPv4 and IPv6 ones come over netlink today, with IFA_MC_USERS for the user count. The link-layer list, dev->mc, is only exported via /proc/net/dev_mcast, so iproute2 and other users still parse procfs for it. This series adds the AF_PACKET family to RTM_GETMULTICAST so that the link-layer multicast addresses are reported the same way. Patch 3 dumps dev->mc in the ifaddrmsg format of the IPv4 and IPv6 dumps: IFA_MULTICAST carries the address, IFA_MC_USERS the reference count and a new IFA_F_GLOBAL flag marks entries added explicitly, the "static" column of /proc/net/dev_mcast. ifa_index limits the dump to one device and IFA_TARGET_NETNSID selects another netns. Patch 2 adds a generation counter for dev->mc changes so a multi-part dump reports NLM_F_DUMP_INTR like the IPv4 and IPv6 ones. Patches 1 and 4 update the rt-addr spec and patch 5 adds a selftest. AF_PACKET dumps returned -EOPNOTSUPP before, so iproute2 can keep the procfs fallback for older kernels. The iproute2 side is ready and will be posted once this is in. Changes in v7: - Add a per netns generation counter bumped on dev->mc changes and fold it into cb->seq, dev_base_seq alone did not cover the dumped entries - Sample cb->seq under the address lock of each device and again when a dump round ends, so the NLMSG_DONE check sees a change too - Drop the Reviewed-by tag of patch 3 after these changes Changes in v6: - Move the dump to net/core/dev_addr_lists.c next to the dev->mc helpers - Stamp cb->seq from dev_base_seq and check dump consistency - Let an unexpected dump error propagate instead of skipping - Check for an address only present in the peer netns in the target-netnsid selftest, the peer and local ifindex can be equal - Document the ifa-index filter and the zero header fields in the spec Changes in v5: - Filter the target-netnsid selftest dump by ifa-index, a new netns also contains the fallback tunnel devices Changes in v4: - Reset the resume offset when the device the dump stopped at is gone - Use a tracked netns reference (put_net_track) - Say ifa-family must be set in the spec doc, drop the AF_UNSPEC remark - Close the netlink socket and guard the checks in the selftest - Drop the Fixes tag Changes in v3: - Report the static bit as a new IFA_F_GLOBAL flag in IFA_FLAGS instead of IFA_F_PERMANENT - Support IFA_TARGET_NETNSID and test it - Describe global_use accurately, it is also set by dev_mc_add_excl() - Fix the target-netnsid type in the rt-addr spec, as its own patch Changes in v2: - Always validate the request header, not only with strict checking - Use a single "with" statement in the selftest (ruff) Yuyang Huang (5): netlink: specs: rt-addr: fix the type of target-netnsid net: add a generation counter for dev->mc changes net: add AF_PACKET multicast dumps netlink: specs: rt-addr: document AF_PACKET multicast dumps selftests: net: test AF_PACKET multicast dumps Documentation/netlink/specs/rt-addr.yaml | 19 +- include/linux/netdevice.h | 4 + include/net/net_namespace.h | 1 + include/uapi/linux/if_addr.h | 1 + net/core/dev_addr_lists.c | 216 +++++++++++++++++++++++ net/core/rtnetlink.c | 2 + tools/testing/selftests/net/rtnetlink.py | 73 +++++++- 7 files changed, 311 insertions(+), 5 deletions(-) -- 2.43.0