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selftests/bpf: Pass page size from userspace in sockopt_sk

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Since there is no convenient way for bpf program to get PAGE_SIZE
from inside of the kernel, pass the value from userspace.

Zero-initialize the variable in bpf prog, otherwise it will cause
problems on some versions of Clang.

Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210408061310.95877-3-yauheni.kaliuta@redhat.com
This commit is contained in:
Yauheni Kaliuta 2021-04-08 09:13:04 +03:00 committed by Andrii Nakryiko
parent cad99cce13
commit 361d32028c
2 changed files with 6 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
tools/testing/selftests/bpf/prog_tests/sockopt_sk.c
View file

@ -200,6 +200,8 @@ static void run_test(int cgroup_fd)
if (!ASSERT_OK_PTR(skel, "skel_load"))
goto cleanup;
skel->bss->page_size = getpagesize();
skel->links._setsockopt =
bpf_program__attach_cgroup(skel->progs._setsockopt, cgroup_fd);
if (!ASSERT_OK_PTR(skel->links._setsockopt, "setsockopt_link"))

10
tools/testing/selftests/bpf/progs/sockopt_sk.c
View file

@ -7,9 +7,7 @@
char _license[] SEC("license") = "GPL";
#ifndef PAGE_SIZE
#define PAGE_SIZE 4096
#endif
int page_size = 0; /* userspace should set it */
#ifndef SOL_TCP
#define SOL_TCP IPPROTO_TCP
@ -89,7 +87,7 @@ int _getsockopt(struct bpf_sockopt *ctx)
* program can only see the first PAGE_SIZE
* bytes of data.
*/
if (optval_end - optval != PAGE_SIZE)
if (optval_end - optval != page_size)
return 0; /* EPERM, unexpected data size */
return 1;
@ -160,7 +158,7 @@ int _setsockopt(struct bpf_sockopt *ctx)
if (ctx->level == SOL_IP && ctx->optname == IP_FREEBIND) {
/* Original optlen is larger than PAGE_SIZE. */
if (ctx->optlen != PAGE_SIZE * 2)
if (ctx->optlen != page_size * 2)
return 0; /* EPERM, unexpected data size */
if (optval + 1 > optval_end)
@ -174,7 +172,7 @@ int _setsockopt(struct bpf_sockopt *ctx)
* program can only see the first PAGE_SIZE
* bytes of data.
*/
if (optval_end - optval != PAGE_SIZE)
if (optval_end - optval != page_size)
return 0; /* EPERM, unexpected data size */
return 1;