The bridge input code may drop frames for various reasons and at various points in the ingress handling logic. Currently kfree_skb() is used everywhere, and therefore no drop reason is specified. Add drop reasons to the most common drop points. The purpose of this series is to address the most common drop points on the bridge ingress path. It does not exhaustively add drop reasons to the entire bridge code. The intention here is to incrementally add drop reasons to the rest of the bridge code in follow up patches. Most of the skb drop points that are addressed in this series can be easily tested by sending crafted packets. The diagram below shows a simple test configuration, and some examples using `packit`(*) are also included. The bridge is set up with STP disabled. (*) https://github.com/resurrecting-open-source-projects/packit The following changes were *not* tested: * SKB_DROP_REASON_NOMEM in br_flood(). It's not easy to trigger an OOM condition for testing purposes, while everything else works correctly. * All drop reasons in br_multicast_flood(). I could not find an easy way to make a crafted packet get there. * SKB_DROP_REASON_BRIDGE_INGRESS_STP_STATE in br_handle_frame_finish() when the port state is BR_STATE_DISABLED, because in that case the frame is already dropped in the switch/case block at the end of br_handle_frame(). +-------+ | br0 | +---+---+ | +---+---+ veth pair +-------+ | veth0 +-------------+ xeth0 | +-------+ +-------+ SKB_DROP_REASON_MAC_INVALID_SOURCE - br_handle_frame() packit -t UDP -s 192.168.0.1 -d 192.168.0.2 -S 8000 -D 8000 \ -e 01:22:33:44:55:66 -E aa:bb:cc:dd:ee:ff -c 1 \ -p '0x de ad be ef' -i xeth0 SKB_DROP_REASON_MAC_IEEE_MAC_CONTROL - br_handle_frame() packit -t UDP -s 192.168.0.1 -d 192.168.0.2 -S 8000 -D 8000 \ -e 02:22:33:44:55:66 -E 01:80:c2:00:00:01 -c 1 \ -p '0x de ad be ef' -i xeth0 SKB_DROP_REASON_BRIDGE_INGRESS_STP_STATE - br_handle_frame() bridge link set dev veth0 state 0 # disabled packit -t UDP -s 192.168.0.1 -d 192.168.0.2 -S 8000 -D 8000 \ -e 02:22:33:44:55:66 -E aa:bb:cc:dd:ee:ff -c 1 \ -p '0x de ad be ef' -i xeth0 SKB_DROP_REASON_BRIDGE_INGRESS_STP_STATE - br_handle_frame_finish() bridge link set dev veth0 state 2 # learning packit -t UDP -s 192.168.0.1 -d 192.168.0.2 -S 8000 -D 8000 \ -e 02:22:33:44:55:66 -E aa:bb:cc:dd:ee:ff -c 1 \ -p '0x de ad be ef' -i xeth0 SKB_DROP_REASON_NO_TX_TARGET - br_flood() packit -t UDP -s 192.168.0.1 -d 192.168.0.2 -S 8000 -D 8000 \ -e 02:22:33:44:55:66 -E aa:bb:cc:dd:ee:ff -c 1 \ -p '0x de ad be ef' -i xeth0 Changes since v1: - Add patch #1, which makes it possible to reuse the existing SKB_DROP_REASON_VXLAN_NO_REMOTE drop reason from vxlan in the bridge module, where a similar drop case exists. - Don't add SKB_DROP_REASON_BRIDGE_NO_EGRESS_PORT. Instead, use either SKB_DROP_REASON_NO_TX_TARGET or SKB_DROP_REASON_NOMEM, depending on the case. - For better clarity, rename SKB_DROP_REASON_BRIDGE_INGRESS_PORT_NFWD to SKB_DROP_REASON_BRIDGE_INGRESS_STP_STATE. Radu Rendec (2): net: vxlan: rename SKB_DROP_REASON_VXLAN_NO_REMOTE net: bridge: add skb drop reasons to the most common drop points drivers/net/vxlan/vxlan_core.c | 4 ++-- drivers/net/vxlan/vxlan_mdb.c | 2 +- include/net/dropreason-core.h | 18 +++++++++++++++--- net/bridge/br_forward.c | 16 ++++++++++++---- net/bridge/br_input.c | 24 +++++++++++++++--------- 5 files changed, 45 insertions(+), 19 deletions(-) -- 2.47.1
