Re: [PATCH bpf-next 1/6] selftests/bpf: Add post_socket_cb for network_helper_opts

[Martin KaFai Lau <martin.lau@xxxxxxxxx>]

On 5/5/24 4:35 AM, Geliang Tang wrote:
> From: Geliang Tang <tanggeliang@xxxxxxxxxx>
>
> __start_server() sets SO_REUSPORT through setsockopt() when the parameter
> 'reuseport' is set. This patch makes it more flexible by adding a function
> pointer post_socket_cb, together with 'struct post_socket_opts cb_opts'
> for future extension into struct network_helper_opts. Then 'reuseport'
> parameter can be dropped.
>
> Now the original start_reuseport_server() can be implemented by setting a
> newly defined reuseport_cb() function pointer to post_socket_cb filed of
> struct network_helper_opts.
>
> Signed-off-by: Geliang Tang <tanggeliang@xxxxxxxxxx>
> ---
>   tools/testing/selftests/bpf/network_helpers.c | 25 ++++++++++++-------
>   tools/testing/selftests/bpf/network_helpers.h |  4 +++
>   2 files changed, 20 insertions(+), 9 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
> index 054d26e383e0..a7ab05baedb6 100644
> --- a/tools/testing/selftests/bpf/network_helpers.c
> +++ b/tools/testing/selftests/bpf/network_helpers.c
> @@ -81,9 +81,8 @@ int settimeo(int fd, int timeout_ms)
>   #define save_errno_close(fd) ({ int __save = errno; close(fd); errno = __save; })
>   
>   static int __start_server(int type, const struct sockaddr *addr, socklen_t addrlen,
> -			  bool reuseport, const struct network_helper_opts *opts)
> +			  const struct network_helper_opts *opts)
>   {
> -	int on = 1;
>   	int fd;
>   
>   	fd = socket(addr->sa_family, type, opts->proto);
> @@ -95,9 +94,9 @@ static int __start_server(int type, const struct sockaddr *addr, socklen_t addrl
>   	if (settimeo(fd, opts->timeout_ms))
>   		goto error_close;
>   
> -	if (reuseport &&
> -	    setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on))) {
> -		log_err("Failed to set SO_REUSEPORT");
> +	if (opts->post_socket_cb &&
> +	    opts->post_socket_cb(fd, &opts->cb_opts)) {
> +		log_err("Failed to call post_socket_cb");
>   		goto error_close;
>   	}
>   
> @@ -132,7 +131,14 @@ int start_server(int family, int type, const char *addr_str, __u16 port,
>   	if (make_sockaddr(family, addr_str, port, &addr, &addrlen))
>   		return -1;
>   
> -	return __start_server(type, (struct sockaddr *)&addr, addrlen, false, &opts);
> +	return __start_server(type, (struct sockaddr *)&addr, addrlen, &opts);
> +}
> +
> +static int reuseport_cb(int fd, const struct post_socket_opts *opts)
> +{
> +	int on = 1;
> +
> +	return setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on));
>   }
>   
>   int *start_reuseport_server(int family, int type, const char *addr_str,
> @@ -140,6 +146,7 @@ int *start_reuseport_server(int family, int type, const char *addr_str,
>   {
>   	struct network_helper_opts opts = {
>   		.timeout_ms = timeout_ms,
> +		.post_socket_cb = reuseport_cb,
>   	};
>   	struct sockaddr_storage addr;
>   	unsigned int nr_fds = 0;
> @@ -156,7 +163,7 @@ int *start_reuseport_server(int family, int type, const char *addr_str,
>   	if (!fds)
>   		return NULL;
>   
> -	fds[0] = __start_server(type, (struct sockaddr *)&addr, addrlen, true, &opts);
> +	fds[0] = __start_server(type, (struct sockaddr *)&addr, addrlen, &opts);
>   	if (fds[0] == -1)
>   		goto close_fds;
>   	nr_fds = 1;
> @@ -165,7 +172,7 @@ int *start_reuseport_server(int family, int type, const char *addr_str,
>   		goto close_fds;
>   
>   	for (; nr_fds < nr_listens; nr_fds++) {
> -		fds[nr_fds] = __start_server(type, (struct sockaddr *)&addr, addrlen, true, &opts);
> +		fds[nr_fds] = __start_server(type, (struct sockaddr *)&addr, addrlen, &opts);
>   		if (fds[nr_fds] == -1)
>   			goto close_fds;
>   	}
> @@ -183,7 +190,7 @@ int start_server_addr(int type, const struct sockaddr_storage *addr, socklen_t l
>   	if (!opts)
>   		opts = &default_opts;
>   
> -	return __start_server(type, (struct sockaddr *)addr, len, 0, opts);
> +	return __start_server(type, (struct sockaddr *)addr, len, opts);
>   }
>   
>   void free_fds(int *fds, unsigned int nr_close_fds)
> diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
> index c62b54daa914..887075fbf6ec 100644
> --- a/tools/testing/selftests/bpf/network_helpers.h
> +++ b/tools/testing/selftests/bpf/network_helpers.h
> @@ -21,6 +21,8 @@ typedef __u16 __sum16;
>   #define VIP_NUM 5
>   #define MAGIC_BYTES 123
>   
> +struct post_socket_opts {};
> +
>   struct network_helper_opts {
>   	const char *cc;
>   	int timeout_ms;
> @@ -28,6 +30,8 @@ struct network_helper_opts {
>   	bool noconnect;
>   	int type;
>   	int proto;
> +	int (*post_socket_cb)(int fd, const struct post_socket_opts *opts);
> +	struct post_socket_opts cb_opts;

I am going to remove cb_opts from network_helper_opts for now. Lets wait for the 
first use case of post_socket_opts comes up. NULL is always passed to 
post_socket_cb for now.

>   };
>   
>   /* ipv4 test vector */