diff options
| -rw-r--r-- | tools/testing/selftests/bpf/progs/test_pkt_access.c | 38 |
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; |