Re: [PATCH net-next v3 3/3] net: icmp: add reasons of the skb drops to icmp protocol

[David Ahern]

On 3/18/22 1:26 AM, Menglong Dong wrote:
> Yeah, PTYPE seems not suitable. I mean that replace SKB_DROP_REASON_PTYPE_ABSENT
> that is used in __netif_receive_skb_core() with L3_PROTO, which means no L3
> protocol handler (or other device handler) is not found for the
> packet. This seems more
> friendly and not code based.
> 
>>> And use SKB_DROP_REASON_L4_PROTO for the L4 protocol problem,
>>> such as GRE version not supported, ICMP type not supported, etc.
> Is this L4_PROTO followed by anyone?

how about just a generic
	SKB_DROP_REASON_UNHANDLED_PROTO  /* protocol not implemented
					  * or not supported
					  */

in place of current PTYPE_ABSENT (so a rename to remove a Linux code
reference), and then use it for no L3 protocol handler, no L4 protocol
handler, version extensions etc. The instruction pointer to symbol gives
the context of the unsupported protocol.