linux-toradex.git/tools/testing/selftests/bpf/progs/icmp_send.c, branch master

selftests/bpf: Add bpf_icmp_send recursion test

2026-07-10T09:56:56+00:00

This test is similar to test_icmp_send_unreach_cgroup but checks that,
in case of recursion, meaning that the BPF program calling the kfunc was
re-triggered by the icmp_send done by the kfunc, the kfunc will stop
early and return -EBUSY.

The test attaches to the root cgroup to ensure the ICMP packet generated
by the kfunc re-triggers the BPF program.

Signed-off-by: Mahe Tardy 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Emil Tsalapatis 
Reviewed-by: Jordan Rife 
Acked-by: Stanislav Fomichev 
Link: https://lore.kernel.org/bpf/20260709144900.245904-5-mahe.tardy@gmail.com

selftests/bpf: Add bpf_icmp_send kfunc cgroup_skb IPv6 tests

2026-07-10T09:56:47+00:00

This test extends the existing cgroup_skb tests with IPv6 support.

Note that we need to set IPV6_RECVERR on the socket for IPv6 in
connect_to_fd_nonblock otherwise the error will be ignored even if
we are in the middle of the TCP handshake. See in
net/ipv6/datagram.c:ipv6_icmp_error for more details.

Signed-off-by: Mahe Tardy 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Jordan Rife 
Acked-by: Stanislav Fomichev 
Link: https://lore.kernel.org/bpf/20260709144900.245904-4-mahe.tardy@gmail.com

selftests/bpf: Add bpf_icmp_send kfunc cgroup_skb tests

2026-07-10T09:56:43+00:00

This test opens a server and client, enters a new cgroup, attach a
cgroup_skb program on egress and calls the bpf_icmp_send function from
the client egress so that an ICMP unreach control message is sent back
to the client. It then fetches the message from the error queue to
confirm the correct ICMP unreach code has been sent.

Note that, for the client, we have to connect in non-blocking mode to
let the test execute faster. Otherwise, we need to wait for the TCP
three-way handshake to timeout in the kernel before reading the errno.

Also note that we don't set IP_RECVERR on the socket in
connect_to_fd_nonblock since the error will be transferred anyway in our
test because the connection is rejected at the beginning of the TCP
handshake. See in net/ipv4/tcp_ipv4.c:tcp_v4_err for more details.

Signed-off-by: Mahe Tardy 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Jordan Rife 
Reviewed-by: Emil Tsalapatis 
Acked-by: Stanislav Fomichev 
Link: https://lore.kernel.org/bpf/20260709144900.245904-3-mahe.tardy@gmail.com