Antonio Pastor a024e377ef net: llc: reset skb->transport_header ... 802.2+LLC+SNAP frames received by napi_complete_done with GRO and DSA have skb->transport_header set two bytes short, or pointing 2 bytes before network_header & skb->data. As snap_rcv expects transport_header to point to SNAP header (OID:PID) after LLC processing advances offset over LLC header (llc_rcv & llc_fixup_skb), code doesn't find a match and packet is dropped. Between napi_complete_done and snap_rcv, transport_header is not used until __netif_receive_skb_core, where originally it was being reset. Commit fda55eca5a ("net: introduce skb_transport_header_was_set()") only does so if not set, on the assumption the value was set correctly by GRO (and also on assumption that "network stacks usually reset the transport header anyway"). Afterwards it is moved forward by llc_fixup_skb. Locally generated traffic shows up at __netif_receive_skb_core with no transport_header set and is processed without issue. On a setup with GRO but no DSA, transport_header and network_header are both set to point to skb->data which is also correct. As issue is LLC specific, to avoid impacting non-LLC traffic, and to follow up on original assumption made on previous code change, llc_fixup_skb to reset the offset after skb pull. llc_fixup_skb assumes the LLC header is at skb->data, and by definition SNAP header immediately follows. Fixes: fda55eca5a ("net: introduce skb_transport_header_was_set()") Signed-off-by: Antonio Pastor <antonio.pastor@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20241225010723.2830290-1-antonio.pastor@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>		2024-12-27 11:23:37 -08:00
..
af_llc.c	llc: Improve setsockopt() handling of malformed user input	2024-11-28 08:57:42 +01:00
Kconfig
llc_c_ac.c
llc_c_ev.c
llc_c_st.c	llc: Constify struct llc_conn_state_trans	2024-07-15 08:51:01 -07:00
llc_conn.c	llc: Constify struct llc_conn_state_trans	2024-07-15 08:51:01 -07:00
llc_core.c	llc: Drop support for ETH_P_TR_802_2.	2024-01-19 21:30:09 -08:00
llc_if.c
llc_input.c	net: llc: reset skb->transport_header	2024-12-27 11:23:37 -08:00
llc_output.c
llc_pdu.c
llc_proc.c
llc_s_ac.c
llc_s_ev.c
llc_s_st.c	llc: Constify struct llc_sap_state_trans	2024-07-15 08:51:19 -07:00
llc_sap.c	llc: Constify struct llc_sap_state_trans	2024-07-15 08:51:19 -07:00
llc_station.c
Makefile
sysctl_net_llc.c	net: Remove ctl_table sentinel elements from several networking subsystems	2024-05-03 13:29:42 +01:00