On Thu, Oct 05, 2023 at 10:18 PM -07, Martin KaFai Lau wrote:
> On 10/5/23 12:21 AM, Geliang Tang wrote:
>> --- a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
>> +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
>> @@ -1336,32 +1336,22 @@ static void test_redir(struct test_sockmap_listen *skel, struct bpf_map *map,
>> }
>> }
>> -static void unix_redir_to_connected(int sotype, int sock_mapfd,
>> - int verd_mapfd, enum redir_mode mode)
>> +static void pairs_redir_to_connected(int cli0, int peer0, int cli1, int peer1,
>> + int sock_mapfd, int verd_mapfd, enum redir_mode mode)
>> {
>> const char *log_prefix = redir_mode_str(mode);
>> - int c0, c1, p0, p1;
>> unsigned int pass;
>> int err, n;
>> - int sfd[2];
>> u32 key;
>> char b;
>> zero_verdict_count(verd_mapfd);
>> - if (socketpair(AF_UNIX, sotype | SOCK_NONBLOCK, 0, sfd))
>> - return;
>> - c0 = sfd[0], p0 = sfd[1];
>> -
>> - if (socketpair(AF_UNIX, sotype | SOCK_NONBLOCK, 0, sfd))
>> - goto close0;
>> - c1 = sfd[0], p1 = sfd[1];
>> -
>> - err = add_to_sockmap(sock_mapfd, p0, p1);
>> + err = add_to_sockmap(sock_mapfd, peer0, peer1);
>> if (err)
>> goto close;
>> - n = write(c1, "a", 1);
>> + n = write(cli1, "a", 1);
>> if (n < 0)
>> FAIL_ERRNO("%s: write", log_prefix);
>> if (n == 0)
>> @@ -1376,16 +1366,34 @@ static void unix_redir_to_connected(int sotype, int sock_mapfd,
>> if (pass != 1)
>> FAIL("%s: want pass count 1, have %d", log_prefix, pass);
>> - n = recv_timeout(mode == REDIR_INGRESS ? p0 : c0, &b, 1, 0,
>> IO_TIMEOUT_SEC);
>> + n = recv_timeout(mode == REDIR_INGRESS ? peer0 : cli0, &b, 1, 0, IO_TIMEOUT_SEC);
>> if (n < 0)
>> FAIL_ERRNO("%s: recv_timeout", log_prefix);
>> if (n == 0)
>> FAIL("%s: incomplete recv", log_prefix);
>> close:
>> - xclose(c1);
>> - xclose(p1);
>> -close0:
>> + xclose(cli1);
>> + xclose(peer1);
>> +}
>> +
>> +static void unix_redir_to_connected(int sotype, int sock_mapfd,
>> + int verd_mapfd, enum redir_mode mode)
>> +{
>> + int c0, c1, p0, p1;
>> + int sfd[2];
>> +
>> + if (socketpair(AF_UNIX, sotype | SOCK_NONBLOCK, 0, sfd))
>> + return;
>> + c0 = sfd[0], p0 = sfd[1];
>> +
>> + if (socketpair(AF_UNIX, sotype | SOCK_NONBLOCK, 0, sfd))
>> + goto close;
>> + c1 = sfd[0], p1 = sfd[1];
>> +
>> + pairs_redir_to_connected(c0, p0, c1, p1, sock_mapfd, verd_mapfd, mode);
>> +
>> +close:
>> xclose(c0);
>> xclose(p0);
>> }
>> @@ -1661,51 +1669,19 @@ static int inet_socketpair(int family, int type, int *s, int *c)
>> static void udp_redir_to_connected(int family, int sock_mapfd, int verd_mapfd,
>> enum redir_mode mode)
>> {
>> - const char *log_prefix = redir_mode_str(mode);
>> int c0, c1, p0, p1;
>> - unsigned int pass;
>> - int err, n;
>> - u32 key;
>> - char b;
>> -
>> - zero_verdict_count(verd_mapfd);
>> + int err;
>> err = inet_socketpair(family, SOCK_DGRAM, &p0, &c0);
>> if (err)
>> return;
>> err = inet_socketpair(family, SOCK_DGRAM, &p1, &c1);
>> if (err)
>> - goto close_cli0;
>> -
>> - err = add_to_sockmap(sock_mapfd, p0, p1);
>> - if (err)
>> - goto close_cli1;
>> -
>> - n = write(c1, "a", 1);
>> - if (n < 0)
>> - FAIL_ERRNO("%s: write", log_prefix);
>> - if (n == 0)
>> - FAIL("%s: incomplete write", log_prefix);
>> - if (n < 1)
>> - goto close_cli1;
>> -
>> - key = SK_PASS;
>> - err = xbpf_map_lookup_elem(verd_mapfd, &key, &pass);
>> - if (err)
>> - goto close_cli1;
>> - if (pass != 1)
>> - FAIL("%s: want pass count 1, have %d", log_prefix, pass);
>> + goto close;
>> - n = recv_timeout(mode == REDIR_INGRESS ? p0 : c0, &b, 1, 0,
>> IO_TIMEOUT_SEC);
>> - if (n < 0)
>> - FAIL_ERRNO("%s: recv_timeout", log_prefix);
>> - if (n == 0)
>> - FAIL("%s: incomplete recv", log_prefix);
>> + pairs_redir_to_connected(c0, p0, c1, p1, sock_mapfd, verd_mapfd, mode);
>> -close_cli1:
>> - xclose(c1);
>> - xclose(p1);
>> -close_cli0:
>> +close:
>> xclose(c0);
>> xclose(p0);
>
> Patch 1 is applied. Thanks.
>
> In patch 2, the xclose() here is confusing after this change. It is also
> inconsistent from how other tests in sockmap_listen.c is doing it. c0/p0 and
> c1/p1 are opened here but only c0/p0 is closed here and c1/p1 is closed in the
> pairs_redir_to_connected() above instead.
I agree with Martin.
The refactoring idea itself is nice. But, I also find it surprising that
newly extracted pairs_redir_to_connected helper takes ownership of cli1
& peer1 FDs.
For me, ideally, we would start using the __cleanup__ attribute, like we
do now in the kernel code [1], to auto-close FDs on return. That would
make error recovery and resource release less verbose.
[1] https://elixir.bootlin.com/linux/v6.5/source/include/linux/cleanup.h
