Re: [PATCH v1 bpf-next 11/11] bpf: Test BPF_SK_REUSEPORT_SELECT_OR_MIGRATE.

[Martin KaFai Lau]

On Tue, Dec 01, 2020 at 11:44:18PM +0900, Kuniyuki Iwashima wrote:
> This patch adds a test for BPF_SK_REUSEPORT_SELECT_OR_MIGRATE.
> 
> Reviewed-by: Benjamin Herrenschmidt <benh@xxxxxxxxxx>
> Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxxxx>
> ---
>  .../bpf/prog_tests/migrate_reuseport.c        | 164 ++++++++++++++++++
>  .../bpf/progs/test_migrate_reuseport_kern.c   |  54 ++++++
>  2 files changed, 218 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/prog_tests/migrate_reuseport.c
>  create mode 100644 tools/testing/selftests/bpf/progs/test_migrate_reuseport_kern.c
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/migrate_reuseport.c b/tools/testing/selftests/bpf/prog_tests/migrate_reuseport.c
> new file mode 100644
> index 000000000000..87c72d9ccadd
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/migrate_reuseport.c
> @@ -0,0 +1,164 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Check if we can migrate child sockets.
> + *
> + *   1. call listen() for 5 server sockets.
> + *   2. update a map to migrate all child socket
> + *        to the last server socket (migrate_map[cookie] = 4)
> + *   3. call connect() for 25 client sockets.
> + *   4. call close() for first 4 server sockets.
> + *   5. call accept() for the last server socket.
> + *
> + * Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxxxx>
> + */
> +
> +#include <stdlib.h>
> +#include <unistd.h>
> +#include <fcntl.h>
> +#include <netinet/in.h>
> +#include <arpa/inet.h>
> +#include <linux/bpf.h>
> +#include <sys/socket.h>
> +#include <sys/types.h>
> +#include <bpf/bpf.h>
> +#include <bpf/libbpf.h>
> +
> +#define NUM_SOCKS 5
> +#define LOCALHOST "127.0.0.1"
> +#define err_exit(condition, message)			      \
> +	do {						      \
> +		if (condition) {			      \
> +			perror("ERROR: " message " ");	      \
> +			exit(1);			      \
> +		}					      \
> +	} while (0)
> +
> +__u64 server_fds[NUM_SOCKS];
> +int prog_fd, reuseport_map_fd, migrate_map_fd;
> +
> +
> +void setup_bpf(void)
> +{
> +	struct bpf_object *obj;
> +	struct bpf_program *prog;
> +	struct bpf_map *reuseport_map, *migrate_map;
> +	int err;
> +
> +	obj = bpf_object__open("test_migrate_reuseport_kern.o");
> +	err_exit(libbpf_get_error(obj), "opening BPF object file failed");
> +
> +	err = bpf_object__load(obj);
> +	err_exit(err, "loading BPF object failed");
> +
> +	prog = bpf_program__next(NULL, obj);
> +	err_exit(!prog, "loading BPF program failed");
> +
> +	reuseport_map = bpf_object__find_map_by_name(obj, "reuseport_map");
> +	err_exit(!reuseport_map, "loading BPF reuseport_map failed");
> +
> +	migrate_map = bpf_object__find_map_by_name(obj, "migrate_map");
> +	err_exit(!migrate_map, "loading BPF migrate_map failed");
> +
> +	prog_fd = bpf_program__fd(prog);
> +	reuseport_map_fd = bpf_map__fd(reuseport_map);
> +	migrate_map_fd = bpf_map__fd(migrate_map);
> +}
> +
> +void test_listen(void)
> +{
> +	struct sockaddr_in addr;
> +	socklen_t addr_len = sizeof(addr);
> +	int i, err, optval = 1, migrated_to = NUM_SOCKS - 1;
> +	__u64 value;
> +
> +	addr.sin_family = AF_INET;
> +	addr.sin_port = htons(80);
> +	inet_pton(AF_INET, LOCALHOST, &addr.sin_addr.s_addr);
> +
> +	for (i = 0; i < NUM_SOCKS; i++) {
> +		server_fds[i] = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
> +		err_exit(server_fds[i] == -1, "socket() for listener sockets failed");
> +
> +		err = setsockopt(server_fds[i], SOL_SOCKET, SO_REUSEPORT,
> +				 &optval, sizeof(optval));
> +		err_exit(err == -1, "setsockopt() for SO_REUSEPORT failed");
> +
> +		if (i == 0) {
> +			err = setsockopt(server_fds[i], SOL_SOCKET, SO_ATTACH_REUSEPORT_EBPF,
> +					 &prog_fd, sizeof(prog_fd));
> +			err_exit(err == -1, "setsockopt() for SO_ATTACH_REUSEPORT_EBPF failed");
> +		}
> +
> +		err = bind(server_fds[i], (struct sockaddr *)&addr, addr_len);
> +		err_exit(err == -1, "bind() failed");
> +
> +		err = listen(server_fds[i], 32);
> +		err_exit(err == -1, "listen() failed");
> +
> +		err = bpf_map_update_elem(reuseport_map_fd, &i, &server_fds[i], BPF_NOEXIST);
> +		err_exit(err == -1, "updating BPF reuseport_map failed");
> +
> +		err = bpf_map_lookup_elem(reuseport_map_fd, &i, &value);
> +		err_exit(err == -1, "looking up BPF reuseport_map failed");
> +
> +		printf("fd[%d] (cookie: %llu) -> fd[%d]\n", i, value, migrated_to);
> +		err = bpf_map_update_elem(migrate_map_fd, &value, &migrated_to, BPF_NOEXIST);
> +		err_exit(err == -1, "updating BPF migrate_map failed");
> +	}
> +}
> +
> +void test_connect(void)
> +{
> +	struct sockaddr_in addr;
> +	socklen_t addr_len = sizeof(addr);
> +	int i, err, client_fd;
> +
> +	addr.sin_family = AF_INET;
> +	addr.sin_port = htons(80);
> +	inet_pton(AF_INET, LOCALHOST, &addr.sin_addr.s_addr);
> +
> +	for (i = 0; i < NUM_SOCKS * 5; i++) {
> +		client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
> +		err_exit(client_fd == -1, "socket() for listener sockets failed");
> +
> +		err = connect(client_fd, (struct sockaddr *)&addr, addr_len);
> +		err_exit(err == -1, "connect() failed");
> +
> +		close(client_fd);
> +	}
> +}
> +
> +void test_close(void)
> +{
> +	int i;
> +
> +	for (i = 0; i < NUM_SOCKS - 1; i++)
> +		close(server_fds[i]);
> +}
> +
> +void test_accept(void)
> +{
> +	struct sockaddr_in addr;
> +	socklen_t addr_len = sizeof(addr);
> +	int cnt, client_fd;
> +
> +	fcntl(server_fds[NUM_SOCKS - 1], F_SETFL, O_NONBLOCK);
> +
> +	for (cnt = 0; cnt < NUM_SOCKS * 5; cnt++) {
> +		client_fd = accept(server_fds[NUM_SOCKS - 1], (struct sockaddr *)&addr, &addr_len);
> +		err_exit(client_fd == -1, "accept() failed");
> +	}
> +
> +	printf("%d accepted, %d is expected\n", cnt, NUM_SOCKS * 5);
> +}
> +
> +int main(void)
I am pretty sure "make -C tools/testing/selftests/bpf"
will not compile here because of double main() with
the test_progs.c.

Please take a look at how other tests are written in
tools/testing/selftests/bpf/prog_tests/. e.g.
the test function in tcp_hdr_options.c is
test_tcp_hdr_options().

Also, instead of bpf_object__open(), please use skeleton
like most of the tests do.


> +{
> +	setup_bpf();
> +	test_listen();
> +	test_connect();
> +	test_close();
> +	test_accept();
> +	close(server_fds[NUM_SOCKS - 1]);
> +	return 0;
> +}