Re: [PATCH net-next v2 6/7] net: add ip4_parse()

Hi Michael,

On Thu, Oct 15, 2026 at 08:41:45AM -0400, Michael S. Tsirkin wrote:

Multiple places in the net stack open-code the same minimal IPv4 header
validation: pull the fixed header, check version 4 and IHL >= 5 (where 5
is the fixed header size in 32-bit units) - and locate the transport
header at IHL * 4 past the network header.

Add a helper for doing that: it returns the validated header and
the transport header offset, or NULL if truncated or malformed.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: LLM

Reviewed-by: Phil Sutter <phil@nwl.cc>

Did you consider nft_inner_parse_l2l3 in net/netfilter/nft_inner.c and
ip_mc_check_iphdr in net/ipv4/igmp.c as well?

Cheers, Phil