// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2023 Facebook */
#include <test_progs.h>
#include <linux/in6.h>
#include <sys/socket.h>
#include <sched.h>
#include <unistd.h>
#include "cgroup_helpers.h"
#include "testing_helpers.h"
#include "cgroup_tcp_skb.skel.h"
#include "cgroup_tcp_skb.h"
#include "network_helpers.h"

#define CGROUP_TCP_SKB_PATH "/test_cgroup_tcp_skb"

static int install_filters(int cgroup_fd,
                           struct bpf_link **egress_link,
                           struct bpf_link **ingress_link,
                           struct bpf_program *egress_prog,
                           struct bpf_program *ingress_prog,
                           struct cgroup_tcp_skb *skel)
{
        /* Prepare filters */
        skel->bss->g_sock_state = 0;
        skel->bss->g_unexpected = 0;
        *egress_link =
                bpf_program__attach_cgroup(egress_prog,
                                           cgroup_fd);
        if (!ASSERT_OK_PTR(egress_link, "egress_link"))
                return -1;
        *ingress_link =
                bpf_program__attach_cgroup(ingress_prog,
                                           cgroup_fd);
        if (!ASSERT_OK_PTR(ingress_link, "ingress_link"))
                return -1;

        return 0;
}

static void uninstall_filters(struct bpf_link **egress_link,
                              struct bpf_link **ingress_link)
{
        bpf_link__destroy(*egress_link);
        *egress_link = NULL;
        bpf_link__destroy(*ingress_link);
        *ingress_link = NULL;
}

static int create_client_sock_v6(void)
{
        int fd;

        fd = socket(AF_INET6, SOCK_STREAM, 0);
        if (fd < 0) {
                perror("socket");
                return -1;
        }

        return fd;
}

/* Connect to the server in a cgroup from the outside of the cgroup. */
static int talk_to_cgroup(int *client_fd, int *listen_fd, int *service_fd,
                          struct cgroup_tcp_skb *skel)
{
        int err, cp;
        char buf[5];
        int port;

        /* Create client & server socket */
        err = join_root_cgroup();
        if (!ASSERT_OK(err, "join_root_cgroup"))
                return -1;
        *client_fd = create_client_sock_v6();
        if (!ASSERT_GE(*client_fd, 0, "client_fd"))
                return -1;
        err = join_cgroup(CGROUP_TCP_SKB_PATH);
        if (!ASSERT_OK(err, "join_cgroup"))
                return -1;
        *listen_fd = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
        if (!ASSERT_GE(*listen_fd, 0, "listen_fd"))
                return -1;
        port = get_socket_local_port(*listen_fd);
        if (!ASSERT_GE(port, 0, "get_socket_local_port"))
                return -1;
        skel->bss->g_sock_port = ntohs(port);

        /* Connect client to server */
        err = connect_fd_to_fd(*client_fd, *listen_fd, 0);
        if (!ASSERT_OK(err, "connect_fd_to_fd"))
                return -1;
        *service_fd = accept(*listen_fd, NULL, NULL);
        if (!ASSERT_GE(*service_fd, 0, "service_fd"))
                return -1;
        err = join_root_cgroup();
        if (!ASSERT_OK(err, "join_root_cgroup"))
                return -1;
        cp = write(*client_fd, "hello", 5);
        if (!ASSERT_EQ(cp, 5, "write"))
                return -1;
        cp = read(*service_fd, buf, 5);
        if (!ASSERT_EQ(cp, 5, "read"))
                return -1;

        return 0;
}

/* Connect to the server out of a cgroup from inside the cgroup. */
static int talk_to_outside(int *client_fd, int *listen_fd, int *service_fd,
                           struct cgroup_tcp_skb *skel)

{
        int err, cp;
        char buf[5];
        int port;

        /* Create client & server socket */
        err = join_root_cgroup();
        if (!ASSERT_OK(err, "join_root_cgroup"))
                return -1;
        *listen_fd = start_server(AF_INET6, SOCK_STREAM, NULL, 0, 0);
        if (!ASSERT_GE(*listen_fd, 0, "listen_fd"))
                return -1;
        err = join_cgroup(CGROUP_TCP_SKB_PATH);
        if (!ASSERT_OK(err, "join_cgroup"))
                return -1;
        *client_fd = create_client_sock_v6();
        if (!ASSERT_GE(*client_fd, 0, "client_fd"))
                return -1;
        err = join_root_cgroup();
        if (!ASSERT_OK(err, "join_root_cgroup"))
                return -1;
        port = get_socket_local_port(*listen_fd);
        if (!ASSERT_GE(port, 0, "get_socket_local_port"))
                return -1;
        skel->bss->g_sock_port = ntohs(port);

        /* Connect client to server */
        err = connect_fd_to_fd(*client_fd, *listen_fd, 0);
        if (!ASSERT_OK(err, "connect_fd_to_fd"))
                return -1;
        *service_fd = accept(*listen_fd, NULL, NULL);
        if (!ASSERT_GE(*service_fd, 0, "service_fd"))
                return -1;
        cp = write(*client_fd, "hello", 5);
        if (!ASSERT_EQ(cp, 5, "write"))
                return -1;
        cp = read(*service_fd, buf, 5);
        if (!ASSERT_EQ(cp, 5, "read"))
                return -1;

        return 0;
}

static int close_connection(int *closing_fd, int *peer_fd, int *listen_fd,
                            struct cgroup_tcp_skb *skel)
{
        __u32 saved_packet_count = 0;
        int err;
        int i;

        /* Wait for ACKs to be sent */
        saved_packet_count = skel->bss->g_packet_count;
        usleep(100000);         /* 0.1s */
        for (i = 0;
             skel->bss->g_packet_count != saved_packet_count && i < 10;
             i++) {
                saved_packet_count = skel->bss->g_packet_count;
                usleep(100000); /* 0.1s */
        }
        if (!ASSERT_EQ(skel->bss->g_packet_count, saved_packet_count,
                       "packet_count"))
                return -1;

        skel->bss->g_packet_count = 0;
        saved_packet_count = 0;

        /* Half shutdown to make sure the closing socket having a chance to
         * receive a FIN from the peer.
         */
        err = shutdown(*closing_fd, SHUT_WR);
        if (!ASSERT_OK(err, "shutdown closing_fd"))
                return -1;

        /* Wait for FIN and the ACK of the FIN to be observed */
        for (i = 0;
             skel->bss->g_packet_count < saved_packet_count + 2 && i < 10;
             i++)
                usleep(100000); /* 0.1s */
        if (!ASSERT_GE(skel->bss->g_packet_count, saved_packet_count + 2,
                       "packet_count"))
                return -1;

        saved_packet_count = skel->bss->g_packet_count;

        /* Fully shutdown the connection */
        err = close(*peer_fd);
        if (!ASSERT_OK(err, "close peer_fd"))
                return -1;
        *peer_fd = -1;

        /* Wait for FIN and the ACK of the FIN to be observed */
        for (i = 0;
             skel->bss->g_packet_count < saved_packet_count + 2 && i < 10;
             i++)
                usleep(100000); /* 0.1s */
        if (!ASSERT_GE(skel->bss->g_packet_count, saved_packet_count + 2,
                       "packet_count"))
                return -1;

        err = close(*closing_fd);
        if (!ASSERT_OK(err, "close closing_fd"))
                return -1;
        *closing_fd = -1;

        close(*listen_fd);
        *listen_fd = -1;

        return 0;
}

/* This test case includes four scenarios:
 * 1. Connect to the server from outside the cgroup and close the connection
 *    from outside the cgroup.
 * 2. Connect to the server from outside the cgroup and close the connection
 *    from inside the cgroup.
 * 3. Connect to the server from inside the cgroup and close the connection
 *    from outside the cgroup.
 * 4. Connect to the server from inside the cgroup and close the connection
 *    from inside the cgroup.
 *
 * The test case is to verify that cgroup_skb/{egress,ingress} filters
 * receive expected packets including SYN, SYN/ACK, ACK, FIN, and FIN/ACK.
 */
void test_cgroup_tcp_skb(void)
{
        struct bpf_link *ingress_link = NULL;
        struct bpf_link *egress_link = NULL;
        int client_fd = -1, listen_fd = -1;
        struct cgroup_tcp_skb *skel;
        int service_fd = -1;
        int cgroup_fd = -1;
        int err;

        skel = cgroup_tcp_skb__open_and_load();
        if (!ASSERT_OK(!skel, "skel_open_load"))
                return;

        err = setup_cgroup_environment();
        if (!ASSERT_OK(err, "setup_cgroup_environment"))
                goto cleanup;

        cgroup_fd = create_and_get_cgroup(CGROUP_TCP_SKB_PATH);
        if (!ASSERT_GE(cgroup_fd, 0, "cgroup_fd"))
                goto cleanup;

        /* Scenario 1 */
        err = install_filters(cgroup_fd, &egress_link, &ingress_link,
                              skel->progs.server_egress,
                              skel->progs.server_ingress,
                              skel);
        if (!ASSERT_OK(err, "install_filters"))
                goto cleanup;

        err = talk_to_cgroup(&client_fd, &listen_fd, &service_fd, skel);
        if (!ASSERT_OK(err, "talk_to_cgroup"))
                goto cleanup;

        err = close_connection(&client_fd, &service_fd, &listen_fd, skel);
        if (!ASSERT_OK(err, "close_connection"))
                goto cleanup;

        ASSERT_EQ(skel->bss->g_unexpected, 0, "g_unexpected");
        ASSERT_EQ(skel->bss->g_sock_state, CLOSED, "g_sock_state");

        uninstall_filters(&egress_link, &ingress_link);

        /* Scenario 2 */
        err = install_filters(cgroup_fd, &egress_link, &ingress_link,
                              skel->progs.server_egress_srv,
                              skel->progs.server_ingress_srv,
                              skel);

        err = talk_to_cgroup(&client_fd, &listen_fd, &service_fd, skel);
        if (!ASSERT_OK(err, "talk_to_cgroup"))
                goto cleanup;

        err = close_connection(&service_fd, &client_fd, &listen_fd, skel);
        if (!ASSERT_OK(err, "close_connection"))
                goto cleanup;

        ASSERT_EQ(skel->bss->g_unexpected, 0, "g_unexpected");
        ASSERT_EQ(skel->bss->g_sock_state, TIME_WAIT, "g_sock_state");

        uninstall_filters(&egress_link, &ingress_link);

        /* Scenario 3 */
        err = install_filters(cgroup_fd, &egress_link, &ingress_link,
                              skel->progs.client_egress_srv,
                              skel->progs.client_ingress_srv,
                              skel);

        err = talk_to_outside(&client_fd, &listen_fd, &service_fd, skel);
        if (!ASSERT_OK(err, "talk_to_outside"))
                goto cleanup;

        err = close_connection(&service_fd, &client_fd, &listen_fd, skel);
        if (!ASSERT_OK(err, "close_connection"))
                goto cleanup;

        ASSERT_EQ(skel->bss->g_unexpected, 0, "g_unexpected");
        ASSERT_EQ(skel->bss->g_sock_state, CLOSED, "g_sock_state");

        uninstall_filters(&egress_link, &ingress_link);

        /* Scenario 4 */
        err = install_filters(cgroup_fd, &egress_link, &ingress_link,
                              skel->progs.client_egress,
                              skel->progs.client_ingress,
                              skel);

        err = talk_to_outside(&client_fd, &listen_fd, &service_fd, skel);
        if (!ASSERT_OK(err, "talk_to_outside"))
                goto cleanup;

        err = close_connection(&client_fd, &service_fd, &listen_fd, skel);
        if (!ASSERT_OK(err, "close_connection"))
                goto cleanup;

        ASSERT_EQ(skel->bss->g_unexpected, 0, "g_unexpected");
        ASSERT_EQ(skel->bss->g_sock_state, TIME_WAIT, "g_sock_state");

        uninstall_filters(&egress_link, &ingress_link);

cleanup:
        close(client_fd);
        close(listen_fd);
        close(service_fd);
        close(cgroup_fd);
        bpf_link__destroy(egress_link);
        bpf_link__destroy(ingress_link);
        cleanup_cgroup_environment();
        cgroup_tcp_skb__destroy(skel);
}