> On Mar 27, 2023, at 9:54 AM, Stanislav Fomichev <sdf@xxxxxxxxxx> wrote:
>
> On 03/27, Aditi Ghag wrote:
>
>
>> > On Mar 24, 2023, at 2:52 PM, Stanislav Fomichev <sdf@xxxxxxxxxx> wrote:
>> >
>> > On 03/23, 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@xxxxxxxxxxxxx>
>> >> ---
>> >> .../selftests/bpf/prog_tests/sock_destroy.c | 195 ++++++++++++++++++
>> >> .../selftests/bpf/progs/sock_destroy_prog.c | 151 ++++++++++++++
>> >> 2 files changed, 346 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..cbce966af568
>> >> --- /dev/null
>> >> +++ b/tools/testing/selftests/bpf/prog_tests/sock_destroy.c
>> >> @@ -0,0 +1,195 @@
>> >> +// SPDX-License-Identifier: GPL-2.0
>> >> +#include <test_progs.h>
>> >> +
>> >> +#include "sock_destroy_prog.skel.h"
>> >> +#include "network_helpers.h"
>> >> +
>> >> +#define SERVER_PORT 6062
>> >> +
>> >> +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;
>> >> +
>> >> + serv = start_server(AF_INET6, SOCK_STREAM, NULL, SERVER_PORT, 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 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, 6161, 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;
>> >> + unsigned int num_listens = 5;
>> >> + char buf[1];
>> >> +
>> >> + /* Start reuseport servers. */
>> >> + listen_fds = start_reuseport_server(AF_INET6, SOCK_DGRAM,
>> >> + "::1", SERVER_PORT, 0,
>> >> + num_listens);
>> >> + if (!ASSERT_OK_PTR(listen_fds, "start_reuseport_server"))
>> >> + goto cleanup;
>> >> +
>> >> + /* 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)
>> >> +{
>> >> + int cgroup_fd = 0;
>> >> + struct sock_destroy_prog *skel;
>> >> +
>> >> + 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..8e09d82c50f3
>> >> --- /dev/null
>> >> +++ b/tools/testing/selftests/bpf/progs/sock_destroy_prog.c
>> >> @@ -0,0 +1,151 @@
>> >> +// SPDX-License-Identifier: GPL-2.0
>> >> +
>> >> +#include "vmlinux.h"
>> >> +
>> >> +#include "bpf_tracing_net.h"
>> >> +#include <bpf/bpf_helpers.h>
>> >> +#include <bpf/bpf_endian.h>
>> >> +
>> >> +#define AF_INET6 10
>> >
>> > [..]
>> >
>> >> +/* Keep it in sync with prog_test/sock_destroy. */
>> >> +#define SERVER_PORT 6062
>> >
>> > The test looks good, one optional unrelated nit maybe:
>> >
>> > I've been guilty of these hard-coded ports in the past, but maybe
>> > we should stop hard-coding them? Getting the address of the listener (bound to
>> > port 0) and passing it to the bpf program via global variable should be super
>> > easy now (with the skeletons and network_helpers).
>
>
>> I briefly considered adding the ports in a map, and retrieving them in the test. But it didn't seem worthwhile as the tests should fail clearly when there is a mismatch.
>
> My worry is that the amount of those tests that have a hard-coded port
> grows and at some point somebody will clash with somebody else.
> And it might not be 100% apparent because test_progs is now multi-threaded
> and racy..
>
So you would like the ports to be unique across all the tests.
>Getting the address of the listener (bound to
> port 0) and passing it to the bpf program via global variable should be super
> easy now (with the skeletons and network_helpers).
Just so that we are on the same page, could you point to which network helpers are you referring to here for passing global variables?
>> >
>> > And, unrelated, maybe also fix a bunch of places where the reverse christmas
>> > tree doesn't look reverse anymore?
>
>> Ok. The checks should be part of tooling (e.g., checkpatch) though if they are meant to be enforced consistently, no?
>
> They are networking specific, so they are not part of a checkpath :-(
> I won't say they are consistently enforced, but we try to keep then
> whenever possible.
>
>> >
>> >> +
>> >> +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;
>> >> + struct seq_file *seq = ctx->meta->seq;
>> >> + __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 seq_file *seq = ctx->meta->seq;
>> >> + 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 == SERVER_PORT)
>> >> + bpf_sock_destroy(sk_common);
>> >> +
>> >> + return 0;
>> >> +}
>> >> +
>> >> +
>> >> +SEC("iter/udp")
>> >> +int iter_udp6_client(struct bpf_iter__udp *ctx)
>> >> +{
>> >> + struct seq_file *seq = ctx->meta->seq;
>> >> + 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 seq_file *seq = ctx->meta->seq;
>> >> + 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 == SERVER_PORT)
>> >> + bpf_sock_destroy((struct sock_common *)sk);
>> >> +
>> >> + return 0;
>> >> +}
>> >> +
>> >> +char _license[] SEC("license") = "GPL";
>> >> --
>> >> 2.34.1
