From: Geliang Tang tanggeliang@kylinos.cn
Some callers expect __start_server() helper to pass their own "backlog" value to listen() instead of the default of 1. So this patch adds struct member "backlog" for network_helper_opts to allow callers to set "backlog" value via start_server_str() helper.
listen(fd, 0 /* backlog */) can be used to enforce syncookie. Meaning backlog 0 is a legit value.
Using 0 as a default and changing it to 1 here is fine. It makes the test program easier to write for the common case. Enforcing syncookie mode by using backlog 0 is a niche use case but it should at least have a way for the caller to do that.
Signed-off-by: Geliang Tang tanggeliang@kylinos.cn --- tools/testing/selftests/bpf/network_helpers.c | 2 +- tools/testing/selftests/bpf/network_helpers.h | 4 ++++ 2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c index 44c2c8fa542a..e0cba4178e41 100644 --- a/tools/testing/selftests/bpf/network_helpers.c +++ b/tools/testing/selftests/bpf/network_helpers.c @@ -106,7 +106,7 @@ static int __start_server(int type, const struct sockaddr *addr, socklen_t addrl }
if (type == SOCK_STREAM) { - if (listen(fd, 1) < 0) { + if (listen(fd, opts->backlog ? MAX(opts->backlog, 0) : 1) < 0) { log_err("Failed to listed on socket"); goto error_close; } diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h index 9ea36524b9db..4f26bfc2dbf5 100644 --- a/tools/testing/selftests/bpf/network_helpers.h +++ b/tools/testing/selftests/bpf/network_helpers.h @@ -25,6 +25,10 @@ struct network_helper_opts { int timeout_ms; bool must_fail; int proto; + /* The backlog argument for listen(), defines the maximum length to which + * the queue of pending connections for sockfd may grow. + */ + int backlog; int (*post_socket_cb)(int fd, void *opts); void *cb_opts; };