From a3016a27cea8e6d10b200b9e19c19961c402d106 Mon Sep 17 00:00:00 2001
From: Geliang Tang <tanggeliang@kylinos.cn>
Date: Tue, 9 Jul 2024 17:16:17 +0800
Subject: [PATCH] selftests/bpf: Add backlog for network_helper_opts
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. Thus, -ve backlog value is used here for the
syncookie use case. Please see the comment in network_helpers.h for
the details.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/1660229659b66eaad07aa2126e9c9fe217eba0dd.1720515893.git.tanggeliang@kylinos.cn
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
tools/testing/selftests/bpf/network_helpers.c | 2 +-
tools/testing/selftests/bpf/network_helpers.h | 10 ++++++++++
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 44c2c8fa542ab..e0cba4178e41d 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 9ea36524b9db4..aac5b94d63799 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -25,6 +25,16 @@ struct network_helper_opts {
int timeout_ms;
bool must_fail;
int proto;
+ /* +ve: Passed to listen() as-is.
+ * 0: Default when the test does not set
+ * a particular value during the struct init.
+ * It is changed to 1 before passing to listen().
+ * Most tests only have one on-going connection.
+ * -ve: It is changed to 0 before passing to listen().
+ * It is useful to force syncookie without
+ * changing the "tcp_syncookies" sysctl from 1 to 2.
+ */
+ int backlog;
int (*post_socket_cb)(int fd, void *opts);
void *cb_opts;
};
--
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