net: stmmac: fix l3l4 filter rejecting unsupported offload requests

The basic flow parser in tc_add_basic_flow() does not validate match
keys before proceeding. Unsupported offload configurations such as
partial protocol masks, non-IPv4 network proto, or non-TCP/UDP transport
proto are silently accepted instead of returning -EOPNOTSUPP.

Add validation to return -EOPNOTSUPP early for:
- No network or transport proto present in the key
- Partial protocol mask (only full mask supported)
- Network proto is not IPv4
- Transport proto is not TCP or UDP

Each rejection includes an extack message so the user knows which part
of the match is unsupported.

Also propagate -EOPNOTSUPP from tc_add_basic_flow() in tc_add_flow()
by returning it directly rather than using break. The break was silently
discarding the error for FLOW_CLS_REPLACE operations where entry->in_use
is already true, causing tc_add_flow() to return 0 (success) for
unsupported replace requests.

Fixes: 425eabddaf0f ("net: stmmac: Implement L3/L4 Filters using TC Flower")
Signed-off-by: Rohan G Thomas <rohan.g.thomas@altera.com>
Signed-off-by: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20260714023716.29865-4-muhammad.nazim.amirul.nazle.asmade@altera.com
Reviewed-by: Jakub Raczynski <j.raczynski@samsung.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

0 files changed, 0 insertions, 0 deletions