bpf: Add selftests for raw syncookie helpers

This commit adds selftests for the new BPF helpers:
bpf_tcp_raw_{gen,check}_syncookie_ipv{4,6}.

xdp_synproxy_kern.c is a BPF program that generates SYN cookies on
allowed TCP ports and sends SYNACKs to clients, accelerating synproxy
iptables module.

xdp_synproxy.c is a userspace control application that allows to
configure the following options in runtime: list of allowed ports, MSS,
window scale, TTL.

test_xdp_synproxy.sh is a script that demonstrates the setup of synproxy
with XDP acceleration and serves as a selftest for the new feature.

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>

tools/testing/selftests/bpf/.gitignore

@@ -42,3 +42,4 @@ test_cpp
 *.tmp
 xdpxceiver
 xdp_redirect_multi
+xdp_synproxy

tools/testing/selftests/bpf/Makefile

@@ -72,7 +72,8 @@ TEST_PROGS := test_kmod.sh \
 	test_bpftool.sh \
 	test_bpftool_metadata.sh \
 	test_doc_build.sh \
-	test_xsk.sh
+	test_xsk.sh \
+	test_xdp_synproxy.sh
 
 TEST_PROGS_EXTENDED := with_addr.sh \
 	with_tunnels.sh \
@@ -82,7 +83,7 @@ TEST_PROGS_EXTENDED := with_addr.sh \
 TEST_GEN_PROGS_EXTENDED = test_sock_addr test_skb_cgroup_id_user \
 	flow_dissector_load test_flow_dissector test_tcp_check_syncookie_user \
 	test_lirc_mode2_user xdping test_cpp runqslower bench bpf_testmod.ko \
-	xdpxceiver xdp_redirect_multi
+	xdpxceiver xdp_redirect_multi xdp_synproxy
 
 TEST_CUSTOM_PROGS = $(OUTPUT)/urandom_read