net: filter: BPF testsuite

The testsuite covers classic and internal BPF instructions.
It is particularly useful for JIT compiler developers.
Adds to "net" selftest target.

The testsuite can be used as a set of micro-benchmarks.
It measures execution time of each BPF program in nsec.

This patch adds core framework.

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/Makefile

@@ -14,6 +14,12 @@ all: $(NET_PROGS)
 run_tests: all
 	@/bin/sh ./run_netsocktests || echo "sockettests: [FAIL]"
 	@/bin/sh ./run_afpackettests || echo "afpackettests: [FAIL]"
-
+	@if /sbin/modprobe test_bpf ; then \
+		/sbin/rmmod test_bpf; \
+		echo "test_bpf: ok"; \
+	else \
+		echo "test_bpf: [FAIL]"; \
+		exit 1; \
+	fi
 clean:
 	$(RM) $(NET_PROGS)