Re: [PATCH v5 bpf-next 7/7] selftests/bpf: Test bpf_sock_destroy

Stanislav Fomichev
2023-03-30T18:46:10Z

On 03/30, Aditi Ghag wrote:
> The test cases for destroying sockets mirror the intended usages of the
> bpf_sock_destroy kfunc using iterators.

> The destroy helpers set `ECONNABORTED` error code that we can validate in
> the test code with client sockets. But UDP sockets have an overriding
> error
> code from the disconnect called during abort, so the error code the
> validation is only done for TCP sockets.

> Signed-off-by: Aditi Ghag <aditi.ghag@isovalent.com>
> ---
> .../selftests/bpf/prog_tests/sock_destroy.c | 203 ++++++++++++++++++
> .../selftests/bpf/progs/sock_destroy_prog.c | 147 +++++++++++++
> 2 files changed, 350 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/sock_destroy.c
> create mode 100644 tools/testing/selftests/bpf/progs/sock_destroy_prog.c

> diff --git a/tools/testing/selftests/bpf/prog_tests/sock_destroy.c
> b/tools/testing/selftests/bpf/prog_tests/sock_destroy.c
> new file mode 100644
> index 000000000000..d5d16fabac48
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/sock_destroy.c
> @@ -0,0 +1,203 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <test_progs.h>
> +#include <bpf/bpf_endian.h>
> +
> +#include "sock_destroy_prog.skel.h"
> +#include "network_helpers.h"
> +
> +static void start_iter_sockets(struct bpf_program *prog)
> +{
> + struct bpf_link *link;
> + char buf[50] = {};
> + int iter_fd, len;
> +
> + link = bpf_program__attach_iter(prog, NULL);
> + if (!ASSERT_OK_PTR(link, "attach_iter"))
> + return;
> +
> + iter_fd = bpf_iter_create(bpf_link__fd(link));
> + if (!ASSERT_GE(iter_fd, 0, "create_iter"))
> + goto free_link;
> +
> + while ((len = read(iter_fd, buf, sizeof(buf))) > 0)
> + ;
> + ASSERT_GE(len, 0, "read");
> +
> + close(iter_fd);
> +
> +free_link:
> + bpf_link__destroy(link);
> +}
> +
> +static void test_tcp_client(struct sock_destroy_prog *skel)
> +{
> + int serv = -1, clien = -1, n = 0;
> +
> + serv = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
> + if (!ASSERT_GE(serv, 0, "start_server"))
> + goto cleanup_serv;
> +
> + clien = connect_to_fd(serv, 0);
> + if (!ASSERT_GE(clien, 0, "connect_to_fd"))
> + goto cleanup_serv;
> +
> + serv = accept(serv, NULL, NULL);
> + if (!ASSERT_GE(serv, 0, "serv accept"))
> + goto cleanup;
> +
> + n = send(clien, "t", 1, 0);
> + if (!ASSERT_GE(n, 0, "client send"))
> + goto cleanup;
> +
> + /* Run iterator program that destroys connected client sockets. */
> + start_iter_sockets(skel->progs.iter_tcp6_client);
> +
> + n = send(clien, "t", 1, 0);
> + if (!ASSERT_LT(n, 0, "client_send on destroyed socket"))
> + goto cleanup;
> + ASSERT_EQ(errno, ECONNABORTED, "error code on destroyed socket");
> +
> +
> +cleanup:
> + close(clien);
> +cleanup_serv:
> + close(serv);
> +}
> +
> +static void test_tcp_server(struct sock_destroy_prog *skel)
> +{
> + int serv = -1, clien = -1, n = 0, err;
> + __u16 serv_port = 0;
> +
> + serv = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
> + if (!ASSERT_GE(serv, 0, "start_server"))
> + goto cleanup_serv;
> + err = get_sock_port6(serv, &serv_port);
> + if (!ASSERT_EQ(err, 0, "get_sock_port6"))
> + goto cleanup;
> + skel->bss->serv_port = ntohs(serv_port);

This looks great, thank you for removing those hard codes!

I have one optional nit, feel free to ignore: you do ntohs here and in
the bpf program. Why not store the port in network byte order? Then
you can avoid all those ntohs and compare the ports directly...

> +
> + clien = connect_to_fd(serv, 0);
> + if (!ASSERT_GE(clien, 0, "connect_to_fd"))
> + goto cleanup_serv;
> +
> + serv = accept(serv, NULL, NULL);
> + if (!ASSERT_GE(serv, 0, "serv accept"))
> + goto cleanup;
> +
> + n = send(clien, "t", 1, 0);
> + if (!ASSERT_GE(n, 0, "client send"))
> + goto cleanup;
> +
> + /* Run iterator program that destroys server sockets. */
> + start_iter_sockets(skel->progs.iter_tcp6_server);
> +
> + n = send(clien, "t", 1, 0);
> + if (!ASSERT_LT(n, 0, "client_send on destroyed socket"))
> + goto cleanup;
> + ASSERT_EQ(errno, ECONNRESET, "error code on destroyed socket");
> +
> +
> +cleanup:
> + close(clien);
> +cleanup_serv:
> + close(serv);
> +}
> +
> +
> +static void test_udp_client(struct sock_destroy_prog *skel)
> +{
> + int serv = -1, clien = -1, n = 0;
> +
> + serv = start_server(AF_INET6, SOCK_DGRAM, NULL, 0, 0);
> + if (!ASSERT_GE(serv, 0, "start_server"))
> + goto cleanup_serv;
> +
> + clien = connect_to_fd(serv, 0);
> + if (!ASSERT_GE(clien, 0, "connect_to_fd"))
> + goto cleanup_serv;
> +
> + n = send(clien, "t", 1, 0);
> + if (!ASSERT_GE(n, 0, "client send"))
> + goto cleanup;
> +
> + /* Run iterator program that destroys sockets. */
> + start_iter_sockets(skel->progs.iter_udp6_client);
> +
> + n = send(clien, "t", 1, 0);
> + if (!ASSERT_LT(n, 0, "client_send on destroyed socket"))
> + goto cleanup;
> + /* UDP sockets have an overriding error code after they are
> disconnected,
> + * so we don't check for ECONNABORTED error code.
> + */
> +
> +cleanup:
> + close(clien);
> +cleanup_serv:
> + close(serv);
> +}
> +
> +static void test_udp_server(struct sock_destroy_prog *skel)
> +{
> + int *listen_fds = NULL, n, i, err;
> + unsigned int num_listens = 5;
> + char buf[1];
> + __u16 serv_port;
> +
> + /* Start reuseport servers. */
> + listen_fds = start_reuseport_server(AF_INET6, SOCK_DGRAM,
> + "::1", 0, 0, num_listens);
> + if (!ASSERT_OK_PTR(listen_fds, "start_reuseport_server"))
> + goto cleanup;
> + err = get_sock_port6(listen_fds[0], &serv_port);
> + if (!ASSERT_EQ(err, 0, "get_sock_port6"))
> + goto cleanup;
> + skel->bss->serv_port = ntohs(serv_port);
> +
> + /* Run iterator program that destroys server sockets. */
> + start_iter_sockets(skel->progs.iter_udp6_server);
> +
> + for (i = 0; i < num_listens; ++i) {
> + n = read(listen_fds[i], buf, sizeof(buf));
> + if (!ASSERT_EQ(n, -1, "read") ||
> + !ASSERT_EQ(errno, ECONNABORTED, "error code on destroyed socket"))
> + break;
> + }
> + ASSERT_EQ(i, num_listens, "server socket");
> +
> +cleanup:
> + free_fds(listen_fds, num_listens);
> +}
> +
> +void test_sock_destroy(void)
> +{
> + struct sock_destroy_prog *skel;
> + int cgroup_fd = 0;
> +
> + skel = sock_destroy_prog__open_and_load();
> + if (!ASSERT_OK_PTR(skel, "skel_open"))
> + return;
> +
> + cgroup_fd = test__join_cgroup("/sock_destroy");
> + if (!ASSERT_GE(cgroup_fd, 0, "join_cgroup"))
> + goto close_cgroup_fd;
> +
> + skel->links.sock_connect = bpf_program__attach_cgroup(
> + skel->progs.sock_connect, cgroup_fd);
> + if (!ASSERT_OK_PTR(skel->links.sock_connect, "prog_attach"))
> + goto close_cgroup_fd;
> +
> + if (test__start_subtest("tcp_client"))
> + test_tcp_client(skel);
> + if (test__start_subtest("tcp_server"))
> + test_tcp_server(skel);
> + if (test__start_subtest("udp_client"))
> + test_udp_client(skel);
> + if (test__start_subtest("udp_server"))
> + test_udp_server(skel);
> +
> +
> +close_cgroup_fd:
> + close(cgroup_fd);
> + sock_destroy_prog__destroy(skel);
> +}
> diff --git a/tools/testing/selftests/bpf/progs/sock_destroy_prog.c
> b/tools/testing/selftests/bpf/progs/sock_destroy_prog.c
> new file mode 100644
> index 000000000000..5c1e65d50598
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/sock_destroy_prog.c
> @@ -0,0 +1,147 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include "vmlinux.h"
> +#include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_endian.h>
> +
> +#include "bpf_tracing_net.h"
> +
> +#define AF_INET6 10
> +
> +__u16 serv_port = 0;
> +
> +int bpf_sock_destroy(struct sock_common *sk) __ksym;
> +
> +struct {
> + __uint(type, BPF_MAP_TYPE_ARRAY);
> + __uint(max_entries, 1);
> + __type(key, __u32);
> + __type(value, __u64);
> +} tcp_conn_sockets SEC(".maps");
> +
> +struct {
> + __uint(type, BPF_MAP_TYPE_ARRAY);
> + __uint(max_entries, 1);
> + __type(key, __u32);
> + __type(value, __u64);
> +} udp_conn_sockets SEC(".maps");
> +
> +SEC("cgroup/connect6")
> +int sock_connect(struct bpf_sock_addr *ctx)
> +{
> + int key = 0;
> + __u64 sock_cookie = 0;
> + __u32 keyc = 0;
> +
> + if (ctx->family != AF_INET6 || ctx->user_family != AF_INET6)
> + return 1;
> +
> + sock_cookie = bpf_get_socket_cookie(ctx);
> + if (ctx->protocol == IPPROTO_TCP)
> + bpf_map_update_elem(&tcp_conn_sockets, &key, &sock_cookie, 0);
> + else if (ctx->protocol == IPPROTO_UDP)
> + bpf_map_update_elem(&udp_conn_sockets, &keyc, &sock_cookie, 0);
> + else
> + return 1;
> +
> + return 1;
> +}
> +
> +SEC("iter/tcp")
> +int iter_tcp6_client(struct bpf_iter__tcp *ctx)
> +{
> + struct sock_common *sk_common = ctx->sk_common;
> + __u64 sock_cookie = 0;
> + __u64 *val;
> + int key = 0;
> +
> + if (!sk_common)
> + return 0;
> +
> + if (sk_common->skc_family != AF_INET6)
> + return 0;
> +
> + sock_cookie = bpf_get_socket_cookie(sk_common);
> + val = bpf_map_lookup_elem(&tcp_conn_sockets, &key);
> + if (!val)
> + return 0;
> + /* Destroy connected client sockets. */
> + if (sock_cookie == *val)
> + bpf_sock_destroy(sk_common);
> +
> + return 0;
> +}
> +
> +SEC("iter/tcp")
> +int iter_tcp6_server(struct bpf_iter__tcp *ctx)
> +{
> + struct sock_common *sk_common = ctx->sk_common;
> + struct tcp6_sock *tcp_sk;
> + const struct inet_connection_sock *icsk;
> + const struct inet_sock *inet;
> + __u16 srcp;
> +
> + if (!sk_common)
> + return 0;
> +
> + if (sk_common->skc_family != AF_INET6)
> + return 0;
> +
> + tcp_sk = bpf_skc_to_tcp6_sock(sk_common);
> + if (!tcp_sk)
> + return 0;
> +
> + icsk = &tcp_sk->tcp.inet_conn;
> + inet = &icsk->icsk_inet;
> + srcp = bpf_ntohs(inet->inet_sport);
> +
> + /* Destroy server sockets. */
> + if (srcp == serv_port)
> + bpf_sock_destroy(sk_common);
> +
> + return 0;
> +}
> +
> +
> +SEC("iter/udp")
> +int iter_udp6_client(struct bpf_iter__udp *ctx)
> +{
> + struct udp_sock *udp_sk = ctx->udp_sk;
> + struct sock *sk = (struct sock *) udp_sk;
> + __u64 sock_cookie = 0, *val;
> + int key = 0;
> +
> + if (!sk)
> + return 0;
> +
> + sock_cookie = bpf_get_socket_cookie(sk);
> + val = bpf_map_lookup_elem(&udp_conn_sockets, &key);
> + if (!val)
> + return 0;
> + /* Destroy connected client sockets. */
> + if (sock_cookie == *val)
> + bpf_sock_destroy((struct sock_common *)sk);
> +
> + return 0;
> +}
> +
> +SEC("iter/udp")
> +int iter_udp6_server(struct bpf_iter__udp *ctx)
> +{
> + struct udp_sock *udp_sk = ctx->udp_sk;
> + struct sock *sk = (struct sock *) udp_sk;
> + __u16 srcp;
> + struct inet_sock *inet;
> +
> + if (!sk)
> + return 0;
> +
> + inet = &udp_sk->inet;
> + srcp = bpf_ntohs(inet->inet_sport);
> + if (srcp == serv_port)
> + bpf_sock_destroy((struct sock_common *)sk);
> +
> + return 0;
> +}
> +
> +char _license[] SEC("license") = "GPL";
> --
> 2.34.1