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Gennaro Cimmino
52852ca38b
The RTL839x route rules match the destination in the template's DIP
fields, and the trap rules the switch MAC too, but never the frame
type. An IPv6 frame fills those fields too, so an
IPv6 frame to the switch whose destination ends in the 32 bits of an
offloaded IPv4 prefix takes that prefix's rule and is routed in
hardware, as IPv6, to the IPv4 route's gateway. IPv4-embedded IPv6
addresses under a /96 prefix (RFC 6052), such as the NAT64 prefix
64:ff9b::/96, end that way.
Match FRAME_TYPE IPv4 (2, USER_FIELD_FRAME_TYPE in the Realtek GPL
SDK), which the IACL entry keeps at bits 337:336 with its mask at
121:120, where the PIE writer already puts frame_type.
Measured on an HPE 1920-48G (RTL8393), 10.99.0.0/16 offloaded via
gateway G, forwarding off, 8 IPv6 echo requests to the switch for
2001:db8:5::a63:601 to ...:608, whose low 32 bits are 10.99.6.1 to .8:
- without this change: 8/8 routed to G (hop limit 63), the rule's
packet counter +8
- with this change: none at G, 8/8 at the CPU, counter +0
Destinations with 10.99.6.x in their high 32 bits were not routed on
either. IPv4 routing through the rules was unchanged (prefix order,
neighbour loss and back, a gateway shared by two routes). Both images
were main c282dd1f4d with bench debugfs files and the switch MAC change
for items 3 and 4 of #25768, not posted yet (a later revision of it on
the second, differing in how routes follow a MAC change).
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Gennaro Cimmino <gcimmino@rayonra.net>
Link: https://github.com/openwrt/openwrt/pull/25818
Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>