Date:   Mon, 30 Jul 2018 16:59:36 -0700
From:   Yonghong Song <yhs@...com>
To:     Andrey Ignatov <rdna@...com>, <netdev@...r.kernel.org>
CC:     <ast@...nel.org>, <daniel@...earbox.net>, <brakmo@...com>,
        <kernel-team@...com>
Subject: Re: [PATCH bpf-next 4/4] selftests/bpf: Test for get_socket_cookie



On 7/30/18 9:04 AM, Andrey Ignatov wrote:
> Add test to use get_socket_cookie() from BPF programs of types
> BPF_PROG_TYPE_SOCK_OPS and BPF_PROG_TYPE_CGROUP_SOCK_ADDR.
> 
> The test attaches two programs to cgroup, runs TCP server and client in
> the cgroup and checks that two operations are done properly on client
> socket when user calls connect(2):
> 
> 1. In BPF_CGROUP_INET6_CONNECT socket cookie is used as the key to write
>     new value in a map for client socket.
> 
> 2. In BPF_CGROUP_SOCK_OPS (BPF_SOCK_OPS_TCP_CONNECT_CB callback) the
>     value written in "1." is found by socket cookie, since it's the same
>     socket, and updated.
> 
> Finally the test verifies the value in the map.
> 
> Signed-off-by: Andrey Ignatov <rdna@...com>
> ---
>   tools/testing/selftests/bpf/Makefile          |   6 +-
>   .../selftests/bpf/socket_cookie_prog.c        |  60 +++++
>   .../selftests/bpf/test_socket_cookie.c        | 249 ++++++++++++++++++
>   3 files changed, 313 insertions(+), 2 deletions(-)
>   create mode 100644 tools/testing/selftests/bpf/socket_cookie_prog.c
>   create mode 100644 tools/testing/selftests/bpf/test_socket_cookie.c
> 
> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index 478bf1bcbbf5..1b28277998e2 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -22,7 +22,8 @@ $(TEST_CUSTOM_PROGS): $(OUTPUT)/%: %.c
>   # Order correspond to 'make run_tests' order
>   TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
>   	test_align test_verifier_log test_dev_cgroup test_tcpbpf_user \
> -	test_sock test_btf test_sockmap test_lirc_mode2_user get_cgroup_id_user
> +	test_sock test_btf test_sockmap test_lirc_mode2_user get_cgroup_id_user \
> +	test_socket_cookie
>   
>   TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
>   	test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o     \
> @@ -33,7 +34,7 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
>   	test_btf_haskv.o test_btf_nokv.o test_sockmap_kern.o test_tunnel_kern.o \
>   	test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o \
>   	test_lwt_seg6local.o sendmsg4_prog.o sendmsg6_prog.o test_lirc_mode2_kern.o \
> -	get_cgroup_id_kern.o
> +	get_cgroup_id_kern.o socket_cookie_prog.o
>   
>   # Order correspond to 'make run_tests' order
>   TEST_PROGS := test_kmod.sh \
> @@ -60,6 +61,7 @@ $(TEST_GEN_PROGS_EXTENDED): $(OUTPUT)/libbpf.a
>   $(OUTPUT)/test_dev_cgroup: cgroup_helpers.c
>   $(OUTPUT)/test_sock: cgroup_helpers.c
>   $(OUTPUT)/test_sock_addr: cgroup_helpers.c
> +$(OUTPUT)/test_socket_cookie: cgroup_helpers.c
>   $(OUTPUT)/test_sockmap: cgroup_helpers.c
>   $(OUTPUT)/test_tcpbpf_user: cgroup_helpers.c
>   $(OUTPUT)/test_progs: trace_helpers.c
> diff --git a/tools/testing/selftests/bpf/socket_cookie_prog.c b/tools/testing/selftests/bpf/socket_cookie_prog.c
> new file mode 100644
> index 000000000000..9ff8ac4b0bf6
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/socket_cookie_prog.c
> @@ -0,0 +1,60 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2018 Facebook
> +
> +#include <linux/bpf.h>
> +#include <sys/socket.h>
> +
> +#include "bpf_helpers.h"
> +#include "bpf_endian.h"
> +
> +struct bpf_map_def SEC("maps") socket_cookies = {
> +	.type = BPF_MAP_TYPE_HASH,
> +	.key_size = sizeof(__u64),
> +	.value_size = sizeof(__u32),
> +	.max_entries = 1 << 8,
> +};
> +
> +SEC("cgroup/connect6")
> +int set_cookie(struct bpf_sock_addr *ctx)
> +{
> +	__u32 cookie_value = 0xFF;
> +	__u64 cookie_key;
> +
> +	if (ctx->family != AF_INET6 || ctx->user_family != AF_INET6)
> +		return 1;
> +
> +	cookie_key = bpf_get_socket_cookie(ctx);
> +	if (bpf_map_update_elem(&socket_cookies, &cookie_key, &cookie_value, 0))
> +		return 0;
> +
> +	return 1;
> +}
> +
> +SEC("sockops")
> +int update_cookie(struct bpf_sock_ops *ctx)
> +{
> +	__u32 new_cookie_value;
> +	__u32 *cookie_value;
> +	__u64 cookie_key;
> +
> +	if (ctx->family != AF_INET6)
> +		return 1;
> +
> +	if (ctx->op != BPF_SOCK_OPS_TCP_CONNECT_CB)
> +		return 1;
> +
> +	cookie_key = bpf_get_socket_cookie(ctx);
> +
> +	cookie_value = bpf_map_lookup_elem(&socket_cookies, &cookie_key);
> +	if (!cookie_value)
> +		return 1;
> +
> +	new_cookie_value = (ctx->local_port << 8) | *cookie_value;
> +	bpf_map_update_elem(&socket_cookies, &cookie_key, &new_cookie_value, 0);
> +
> +	return 1;
> +}
> +
> +int _version SEC("version") = 1;
> +
> +char _license[] SEC("license") = "GPL";
> diff --git a/tools/testing/selftests/bpf/test_socket_cookie.c b/tools/testing/selftests/bpf/test_socket_cookie.c
> new file mode 100644
> index 000000000000..eed4b3bc9fcd
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/test_socket_cookie.c
> @@ -0,0 +1,249 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2018 Facebook
> +
> +#include <string.h>
> +#include <unistd.h>
> +
> +#include <arpa/inet.h>
> +#include <netinet/in.h>
> +#include <sys/types.h>
> +#include <sys/socket.h>
> +
> +#include <bpf/bpf.h>
> +#include <bpf/libbpf.h>
> +
> +#include "bpf_rlimit.h"
> +#include "cgroup_helpers.h"
> +
> +#define CG_PATH			"/foo"
> +#define SOCKET_COOKIE_PROG	"./socket_cookie_prog.o"
> +
> +static int attach_type_by_name(const char *prog_name,
> +			       enum bpf_attach_type *attach_type)
> +{
> +	enum bpf_attach_type expected_attach_type;
> +	enum bpf_prog_type prog_type;
> +	int err = 0;
> +
> +	err = libbpf_prog_type_by_name(prog_name, &prog_type,
> +				       &expected_attach_type);
> +	if (err) {
> +		log_err("Failed to get type for prog %s", prog_name);
> +		goto out;
> +	}
> +
> +	if (expected_attach_type) {
> +		*attach_type = expected_attach_type;
> +		goto out;
> +	}
> +
> +	switch (prog_type) {
> +	case BPF_PROG_TYPE_SOCK_OPS:
> +		*attach_type = BPF_CGROUP_SOCK_OPS;
> +		break;
> +	default:
> +		log_err("Can't detect attach type for prog %s", prog_name);
> +		err = -1;
> +	}
> +out:
> +	return err;
> +}
> +
> +static int start_server(void)
> +{
> +	struct sockaddr_in6 addr;
> +	int fd;
> +
> +	fd = socket(AF_INET6, SOCK_STREAM, 0);
> +	if (fd == -1) {
> +		log_err("Failed to create server socket");
> +		goto out;
> +	}
> +
> +	memset(&addr, 0, sizeof(addr));
> +	addr.sin6_family = AF_INET6;
> +	addr.sin6_addr = in6addr_loopback;
> +	addr.sin6_port = 0;
> +
> +	if (bind(fd, (const struct sockaddr *)&addr, sizeof(addr)) == -1) {
> +		log_err("Failed to bind server socket");
> +		goto close_out;
> +	}
> +
> +	if (listen(fd, 128) == -1) {
> +		log_err("Failed to listen on server socket");
> +		goto close_out;
> +	}
> +
> +	goto out;
> +
> +close_out:
> +	close(fd);
> +	fd = -1;
> +out:
> +	return fd;
> +}
> +
> +static int connect_to_server(int server_fd)
> +{
> +	struct sockaddr_storage addr;
> +	socklen_t len = sizeof(addr);
> +	int fd;
> +
> +	fd = socket(AF_INET6, SOCK_STREAM, 0);
> +	if (fd == -1) {
> +		log_err("Failed to create client socket");
> +		goto out;
> +	}
> +
> +	if (getsockname(server_fd, (struct sockaddr *)&addr, &len)) {
> +		log_err("Failed to get server addr");
> +		goto close_out;
> +	}
> +
> +	if (connect(fd, (const struct sockaddr *)&addr, len) == -1) {
> +		log_err("Fail to connect to server");
> +		goto close_out;
> +	}
> +
> +	goto out;
> +
> +close_out:
> +	close(fd);
> +	fd = -1;
> +out:
> +	return fd;
> +}
> +
> +static int validate_map(struct bpf_map *map, int client_fd)
> +{
> +	__u32 cookie_expected_value;
> +	struct sockaddr_in6 addr;
> +	socklen_t len = sizeof(addr);
> +	__u32 cookie_value;
> +	__u64 cookie_key;
> +	int err = 0;
> +	int map_fd;
> +
> +	if (!map) {
> +		log_err("Map not found in BPF object");
> +		goto err;
> +	}
> +
> +	map_fd = bpf_map__fd(map);
> +
> +	err = bpf_map_get_next_key(map_fd, NULL, &cookie_key);
> +	if (err) {
> +		log_err("Can't get cookie key from map");
> +		goto out;
> +	}
> +
> +	err = bpf_map_lookup_elem(map_fd, &cookie_key, &cookie_value);
> +	if (err) {
> +		log_err("Can't get cookie value from map");
> +		goto out;
> +	}
> +
> +	err = getsockname(client_fd, (struct sockaddr *)&addr, &len);
> +	if (err) {
> +		log_err("Can't get client local addr");
> +		goto out;
> +	}
> +
> +	cookie_expected_value = (ntohs(addr.sin6_port) << 8) | 0xFF;
> +	if (cookie_value != cookie_expected_value) {
> +		log_err("Unexpected value in map: %x != %x", cookie_value,
> +			cookie_expected_value);
> +		goto err;
> +	}
> +
> +	goto out;
> +err:
> +	err = -1;
> +out:
> +	return err;
> +}
> +
> +static int run_test(int cgfd)
> +{
> +	enum bpf_attach_type attach_type;
> +	struct bpf_prog_load_attr attr;
> +	struct bpf_program *prog;
> +	struct bpf_object *pobj;
> +	const char *prog_name;
> +	int server_fd = -1;
> +	int client_fd = -1;
> +	int prog_fd = -1;
> +	int err = 0;
> +
> +	memset(&attr, 0, sizeof(attr));
> +	attr.file = SOCKET_COOKIE_PROG;
> +	attr.prog_type = BPF_PROG_TYPE_UNSPEC;
> +
> +	err = bpf_prog_load_xattr(&attr, &pobj, &prog_fd);
> +	if (err) {
> +		log_err("Failed to load %s", attr.file);
> +		goto out;
> +	}
> +
> +	bpf_object__for_each_program(prog, pobj) {
> +		prog_name = bpf_program__title(prog, /*needs_copy*/ false);
> +		err = attach_type_by_name(prog_name, &attach_type);
> +		if (err)
> +			goto out;
> +		err = bpf_prog_attach(bpf_program__fd(prog), cgfd, attach_type,
> +				      BPF_F_ALLOW_OVERRIDE);
> +		if (err) {
> +			log_err("Failed to attach prog %s", prog_name);
> +			goto out;
> +		}
> +	}

Tested and the program runs correctly in my FC27 environment.
I kind of feel that the above attach program and attach_type_by_name
are a little bit complicated since we only have two programs here.

There is a API in libbpf called bpf_object__find_program_by_title, which 
can be used to find the program based on program section name. Could 
this be used to simplify the program load/attachment logic here?

> +	server_fd = start_server();
> +	if (server_fd == -1)
> +		goto err;
> +
> +	client_fd = connect_to_server(server_fd);
> +	if (client_fd == -1)
> +		goto err;
> +
> +	if (validate_map(bpf_map__next(NULL, pobj), client_fd))
> +		goto err;
> +
> +	goto out;
> +err:
> +	err = -1;
> +out:
> +	close(client_fd);
> +	close(server_fd);
> +	bpf_object__close(pobj);
> +	printf("%s\n", err ? "FAILED" : "PASSED");
> +	return err;
> +}
> +
> +int main(int argc, char **argv)
> +{
> +	int cgfd = -1;
> +	int err = 0;
> +
> +	if (setup_cgroup_environment())
> +		goto err;
> +
> +	cgfd = create_and_get_cgroup(CG_PATH);
> +	if (!cgfd)
> +		goto err;
> +
> +	if (join_cgroup(CG_PATH))
> +		goto err;
> +
> +	if (run_test(cgfd))
> +		goto err;
> +
> +	goto out;
> +err:
> +	err = -1;
> +out:
> +	close(cgfd);
> +	cleanup_cgroup_environment();
> +	return err;
> +}
> 

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