On Wed, Jan 24, 2024 at 10:54 AM -08, John Fastabend wrote:
> Sendmsg path with multiple buffers is slightly different from a single
> send in how we have to handle and walk the sg when doing pops. Lets
> ensure this walk is correct.
>
> Signed-off-by: John Fastabend <john.fastabend@xxxxxxxxx>
> ---
> .../bpf/prog_tests/sockmap_helpers.h | 8 +++
> .../bpf/prog_tests/sockmap_msg_helpers.c | 53 +++++++++++++++++++
> 2 files changed, 61 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h b/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
> index 781cbdf01d7b..4d8d24482032 100644
> --- a/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
> +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
> @@ -103,6 +103,14 @@
> __ret; \
> })
>
> +#define xsendmsg(fd, msg, flags) \
> + ({ \
> + ssize_t __ret = sendmsg((fd), (msg), (flags)); \
> + if (__ret == -1) \
> + FAIL_ERRNO("sendmsg"); \
> + __ret; \
> + })
> +
> #define xrecv_nonblock(fd, buf, len, flags) \
> ({ \
> ssize_t __ret = recv_timeout((fd), (buf), (len), (flags), \
> diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_msg_helpers.c b/tools/testing/selftests/bpf/prog_tests/sockmap_msg_helpers.c
> index 9ffe02f45808..e5e618e84950 100644
> --- a/tools/testing/selftests/bpf/prog_tests/sockmap_msg_helpers.c
> +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_msg_helpers.c
> @@ -52,6 +52,50 @@ static void pop_simple_send(struct msg_test_opts *opts, int start, int len)
> ASSERT_OK(cmp, "pop cmp end bytes failed");
> }
>
> +static void pop_complex_send(struct msg_test_opts *opts, int start, int len)
> +{
> + struct test_sockmap_msg_helpers *skel = opts->skel;
> + char buf[] = "abcdefghijklmnopqrstuvwxyz";
> + size_t sent, recv, total = 0;
> + struct msghdr msg = {0};
> + struct iovec iov[15];
> + char *recvbuf;
> + int i;
> +
> + for (i = 0; i < 15; i++) {
Always nice to use ARRAY_SIZE.
> + iov[i].iov_base = buf;
> + iov[i].iov_len = sizeof(buf);
> + total += sizeof(buf);
> + }
> +
> + recvbuf = malloc(total);
> + if (!recvbuf)
> + FAIL("pop complex send malloc failure\n");
390 bytes, why not have it on stack?
> +
> + msg.msg_iov = iov;
> + msg.msg_iovlen = 15;
> +
> + skel->bss->pop = true;
> +
> + if (start == -1)
> + start = sizeof(buf) - len - 1;
> +
> + skel->bss->pop_start = start;
> + skel->bss->pop_len = len;
> +
> + sent = xsendmsg(opts->client, &msg, 0);
> + if (sent != total)
> + FAIL("xsend failed");
> +
> + ASSERT_OK(skel->bss->err, "pop error");
> +
> + recv = xrecv_nonblock(opts->server, recvbuf, total, 0);
> + if (recv != sent - skel->bss->pop_len)
> + FAIL("Received incorrect number number of bytes after pop");
> +
> + free(recvbuf);
> +}
> +
> static void test_sockmap_pop(void)
> {
> struct msg_test_opts opts;
> @@ -92,6 +136,15 @@ static void test_sockmap_pop(void)
> /* Pop from end */
> pop_simple_send(&opts, POP_END, 5);
>
> + /* Empty pop from start of sendmsg */
> + pop_complex_send(&opts, 0, 0);
> + /* Pop from start of sendmsg */
> + pop_complex_send(&opts, 0, 10);
> + /* Pop from middle of sendmsg */
> + pop_complex_send(&opts, 100, 10);
> + /* Pop from end of sendmsg */
> + pop_complex_send(&opts, 394, 10);
Isn't the start offset here past the end? 15*26=390?
> +
> close_sockets:
> close(client);
> close(server);
