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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
This commit is contained in:
Alexei Starovoitov 2019-11-14 10:57:19 -08:00 committed by Daniel Borkmann
parent e7bf94dbb8
commit 4c0963243c
1 changed files with 36 additions and 2 deletions
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38
tools/testing/selftests/bpf/progs/test_pkt_access.c
View File

@ -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;