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authorAlexei Starovoitov <ast@kernel.org>2019-11-14 10:57:19 -0800
committerDaniel Borkmann <daniel@iogearbox.net>2019-11-15 23:45:50 +0100
commit4c0963243c5f56bffe8eaba6acc5b076d51797f4 (patch)
treedcf2b3e9e78fc78843bb1c0b28287309049feb4d /tools
parente7bf94dbb882b7d679a6a18e40e4f28076eb249f (diff)
downloadlinux-4c0963243c5f56bffe8eaba6acc5b076d51797f4.tar.bz2
selftests/bpf: Extend test_pkt_access test
The test_pkt_access.o is used by multiple tests. Fix its section name so that program type can be automatically detected by libbpf and make it call other subprograms with skb argument. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191114185720.1641606-20-ast@kernel.org
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/bpf/progs/test_pkt_access.c38
1 files changed, 36 insertions, 2 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_pkt_access.c b/tools/testing/selftests/bpf/progs/test_pkt_access.c
index 7cf42d14103f..3a7b4b607ed3 100644
--- a/tools/testing/selftests/bpf/progs/test_pkt_access.c
+++ b/tools/testing/selftests/bpf/progs/test_pkt_access.c
@@ -17,8 +17,38 @@
#define barrier() __asm__ __volatile__("": : :"memory")
int _version SEC("version") = 1;
-SEC("test1")
-int process(struct __sk_buff *skb)
+/* llvm will optimize both subprograms into exactly the same BPF assembly
+ *
+ * Disassembly of section .text:
+ *
+ * 0000000000000000 test_pkt_access_subprog1:
+ * ; return skb->len * 2;
+ * 0: 61 10 00 00 00 00 00 00 r0 = *(u32 *)(r1 + 0)
+ * 1: 64 00 00 00 01 00 00 00 w0 <<= 1
+ * 2: 95 00 00 00 00 00 00 00 exit
+ *
+ * 0000000000000018 test_pkt_access_subprog2:
+ * ; return skb->len * val;
+ * 3: 61 10 00 00 00 00 00 00 r0 = *(u32 *)(r1 + 0)
+ * 4: 64 00 00 00 01 00 00 00 w0 <<= 1
+ * 5: 95 00 00 00 00 00 00 00 exit
+ *
+ * Which makes it an interesting test for BTF-enabled verifier.
+ */
+static __attribute__ ((noinline))
+int test_pkt_access_subprog1(volatile struct __sk_buff *skb)
+{
+ return skb->len * 2;
+}
+
+static __attribute__ ((noinline))
+int test_pkt_access_subprog2(int val, volatile struct __sk_buff *skb)
+{
+ return skb->len * val;
+}
+
+SEC("classifier/test_pkt_access")
+int test_pkt_access(struct __sk_buff *skb)
{
void *data_end = (void *)(long)skb->data_end;
void *data = (void *)(long)skb->data;
@@ -48,6 +78,10 @@ int process(struct __sk_buff *skb)
tcp = (struct tcphdr *)((void *)(ip6h) + ihl_len);
}
+ if (test_pkt_access_subprog1(skb) != skb->len * 2)
+ return TC_ACT_SHOT;
+ if (test_pkt_access_subprog2(2, skb) != skb->len * 2)
+ return TC_ACT_SHOT;
if (tcp) {
if (((void *)(tcp) + 20) > data_end || proto != 6)
return TC_ACT_SHOT;