selftests/bpf: Add selftests for netkit

Add a bigger batch of test coverage to assert correct operation of
netkit devices and their BPF program management:

# ./test_progs -t tc_netkit
[...]
[ 1.166267] bpf_testmod: loading out-of-tree module taints kernel.
[ 1.166831] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
[ 1.270957] tsc: Refined TSC clocksource calibration: 3407.988 MHz
[ 1.272579] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fc932722, max_idle_ns: 440795381586 ns
[ 1.275336] clocksource: Switched to clocksource tsc
#257 tc_netkit_basic:OK
#258 tc_netkit_device:OK
#259 tc_netkit_multi_links:OK
#260 tc_netkit_multi_opts:OK
#261 tc_netkit_neigh_links:OK
Summary: 5/0 PASSED, 0 SKIPPED, 0 FAILED
[...]

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20231024214904.29825-8-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

selftests/bpf: Add various more tcx test cases

Add several new tcx test cases to improve test coverage. This also includes
a few new tests with ingress instead of clsact qdisc, to cover the fix from
commit dc644b540a2d ("tcx: Fix splat in ingress_destroy upon tcx_entry_free").

# ./test_progs -t tc
[...]
#234 tc_links_after:OK
#235 tc_links_append:OK
#236 tc_links_basic:OK
#237 tc_links_before:OK
#238 tc_links_chain_classic:OK
#239 tc_links_chain_mixed:OK
#240 tc_links_dev_cleanup:OK
#241 tc_links_dev_mixed:OK
#242 tc_links_ingress:OK
#243 tc_links_invalid:OK
#244 tc_links_prepend:OK
#245 tc_links_replace:OK
#246 tc_links_revision:OK
#247 tc_opts_after:OK
#248 tc_opts_append:OK
#249 tc_opts_basic:OK
#250 tc_opts_before:OK
#251 tc_opts_chain_classic:OK
#252 tc_opts_chain_mixed:OK
#253 tc_opts_delete_empty:OK
#254 tc_opts_demixed:OK
#255 tc_opts_detach:OK
#256 tc_opts_detach_after:OK
#257 tc_opts_detach_before:OK
#258 tc_opts_dev_cleanup:OK
#259 tc_opts_invalid:OK
#260 tc_opts_mixed:OK
#261 tc_opts_prepend:OK
#262 tc_opts_replace:OK
#263 tc_opts_revision:OK
[...]
Summary: 44/38 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/8699efc284b75ccdc51ddf7062fa2370330dc6c0.1692029283.git.daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

selftests/bpf: Add mprog API tests for BPF tcx opts

Add a big batch of test coverage to assert all aspects of the tcx opts
attach, detach and query API:

# ./vmtest.sh -- ./test_progs -t tc_opts
[...]
#238 tc_opts_after:OK
#239 tc_opts_append:OK
#240 tc_opts_basic:OK
#241 tc_opts_before:OK
#242 tc_opts_chain_classic:OK
#243 tc_opts_demixed:OK
#244 tc_opts_detach:OK
#245 tc_opts_detach_after:OK
#246 tc_opts_detach_before:OK
#247 tc_opts_dev_cleanup:OK
#248 tc_opts_invalid:OK
#249 tc_opts_mixed:OK
#250 tc_opts_prepend:OK
#251 tc_opts_replace:OK
#252 tc_opts_revision:OK
Summary: 15/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20230719140858.13224-8-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>