Subject: Re: [PATCH bpf 1/6] selftest/bpf: Support more socket types in create_pair()

From: Jakub Sitnicki <[email-masked]>
Date: Fri, 26 Jul 2024 19:23:41 +0200

On Wed, Jul 24, 2024 at 01:32 PM +02, Michal Luczaj wrote:
> Extend the function to allow creating socket pairs of SOCK_STREAM,
> SOCK_DGRAM and SOCK_SEQPACKET.
>
> Adapt direct callers and leave further cleanups for the following patch.
>
> Suggested-by: Jakub Sitnicki <[email-masked]>
> Signed-off-by: Michal Luczaj <[email-masked]>
> ---
>  .../selftests/bpf/prog_tests/sockmap_basic.c       |  19 +--
>  .../selftests/bpf/prog_tests/sockmap_helpers.h     | 138 ++++++++++++++-------
>  2 files changed, 96 insertions(+), 61 deletions(-)
>

[...]

> diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h b/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
> index e880f97bc44d..77b73333f091 100644
> --- a/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
> +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h

[...]

> +static inline int create_pair(int family, int sotype, int *p0, int *p1)
> +{
> +	struct sockaddr_storage addr;
> +	socklen_t len = sizeof(addr);
> +	int s, c, p, err;
> +
> +	s = socket_loopback(family, sotype);
> +	if (s < 0)
> +		return s;
> +
> +	err = xgetsockname(s, sockaddr(&addr), &len);
> +	if (err)
> +		goto close_s;
> +
> +	c = xsocket(family, sotype, 0);
> +	if (c < 0) {
> +		err = c;
> +		goto close_s;
> +	}
> +
> +	err = connect(c, sockaddr(&addr), len);
> +	if (err) {
> +		if (errno != EINPROGRESS) {
> +			FAIL_ERRNO("connect");
> +			goto close_c;
> +		}
> +
> +		err = poll_connect(c, IO_TIMEOUT_SEC);
> +		if (err) {
> +			FAIL_ERRNO("poll_connect");
> +			goto close_c;
> +		}
> +	}
> +
> +	switch (sotype & SOCK_TYPE_MASK) {
> +	case SOCK_DGRAM:
> +		err = xgetsockname(c, sockaddr(&addr), &len);
> +		if (err)
> +			goto close_c;
> +
> +		err = xconnect(s, sockaddr(&addr), len);
> +		if (!err) {
> +			*p0 = s;
> +			*p1 = c;
> +			return err;
> +		}
> +		break;
> +	case SOCK_STREAM:
> +	case SOCK_SEQPACKET:
> +		p = xaccept_nonblock(s, NULL, NULL);
> +		if (p >= 0) {
> +			*p0 = p;
> +			*p1 = c;
> +			goto close_s;
> +		}
> +
> +		err = p;
> +		break;
> +	default:
> +		FAIL("Unsupported socket type %#x", sotype);
> +		err = -EOPNOTSUPP;
> +	}
> +
> +close_c:
> +	close(c);
> +close_s:
> +	close(s);
> +	return err;
> +}

I was going to suggest that a single return path for success is better
than two (diff below), but I see that this is what you ended up with
after patch 6.

So I think we can leave it as is.

---
diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h b/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
index 77b73333f091..ed266c6c0117 100644
--- a/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
@@ -408,28 +408,31 @@ static inline int create_pair(int family, int sotype, int *p0, int *p1)
                        goto close_c;

                err = xconnect(s, sockaddr(&addr), len);
-               if (!err) {
-                       *p0 = s;
-                       *p1 = c;
-                       return err;
-               }
+               if (err)
+                       goto close_c;
+
+               p = s;
                break;
        case SOCK_STREAM:
        case SOCK_SEQPACKET:
                p = xaccept_nonblock(s, NULL, NULL);
-               if (p >= 0) {
-                       *p0 = p;
-                       *p1 = c;
-                       goto close_s;
+               if (p < 0) {
+                       err = p;
+                       goto close_c;
                }

-               err = p;
+               xclose(s);
                break;
        default:
                FAIL("Unsupported socket type %#x", sotype);
                err = -EOPNOTSUPP;
+               goto close_c;
        }

+       *p0 = p;
+       *p1 = c;
+       return 0;
+
 close_c:
        close(c);
 close_s: