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

Aditi Ghag
2023-03-30T15:19:49Z

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);
+
+ 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