The GRO self-test, gro.c, currently constructs IPv6 packets containing a Hop-by-Hop Options header (IPPROTO_HOPOPTS) to ensure the GRO path correctly handles IPv6 extension headers.

However, network elements may be configured to drop packets with the Hop-by-Hop Options header (HBH). This causes the self-test to fail in environments where such network elements are present.

To improve the robustness and reliability of this test in diverse network environments, switch from using IPPROTO_HOPOPTS to IPPROTO_DSTOPTS (Destination Options).

The Destination Options header is less likely to be dropped by intermediate routers and still serves the core purpose of the test: validating GRO's handling of an IPv6 extension header. This change ensures the test can execute successfully without being incorrectly failed by network policies outside the kernel's control.

Fixes: 7d1575014a63 ("selftests/net: GRO coalesce test") Reviewed-by: Willem de Bruijn willemb@google.com Signed-off-by: Anubhav Singh anubhavsinggh@google.com --- tools/testing/selftests/net/gro.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/gro.c b/tools/testing/selftests/net/gro.c index 2b1d9f2b3e9e..d8c29fe39c1d 100644 --- a/tools/testing/selftests/net/gro.c +++ b/tools/testing/selftests/net/gro.c @@ -754,11 +754,11 @@ static void send_ipv6_exthdr(int fd, struct sockaddr_ll *daddr, char *ext_data1, static char exthdr_pck[sizeof(buf) + MIN_EXTHDR_SIZE];

create_packet(buf, 0, 0, PAYLOAD_LEN, 0); - add_ipv6_exthdr(buf, exthdr_pck, IPPROTO_HOPOPTS, ext_data1); + add_ipv6_exthdr(buf, exthdr_pck, IPPROTO_DSTOPTS, ext_data1); write_packet(fd, exthdr_pck, total_hdr_len + PAYLOAD_LEN + MIN_EXTHDR_SIZE, daddr);

create_packet(buf, PAYLOAD_LEN * 1, 0, PAYLOAD_LEN, 0); - add_ipv6_exthdr(buf, exthdr_pck, IPPROTO_HOPOPTS, ext_data2); + add_ipv6_exthdr(buf, exthdr_pck, IPPROTO_DSTOPTS, ext_data2); write_packet(fd, exthdr_pck, total_hdr_len + PAYLOAD_LEN + MIN_EXTHDR_SIZE, daddr); }