// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
// Copyright (c) 2020 Cloudflare
/*
 * Test BPF attach point for INET socket lookup (BPF_SK_LOOKUP).
 *
 * Tests exercise:
 *  - attaching/detaching/querying programs to BPF_SK_LOOKUP hook,
 *  - redirecting socket lookup to a socket selected by BPF program,
 *  - failing a socket lookup on BPF program's request,
 *  - error scenarios for selecting a socket from BPF program,
 *  - accessing BPF program context,
 *  - attaching and running multiple BPF programs.
 *
 * Tests run in a dedicated network namespace.
 */

#define _GNU_SOURCE
#include <arpa/inet.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <sched.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

#include <bpf/libbpf.h>
#include <bpf/bpf.h>

#include "test_progs.h"
#include "bpf_util.h"
#include "cgroup_helpers.h"
#include "network_helpers.h"
#include "testing_helpers.h"
#include "test_sk_lookup.skel.h"

/* External (address, port) pairs the client sends packets to. */
#define EXT_IP4         "127.0.0.1"
#define EXT_IP6         "fd00::1"
#define EXT_PORT        7007

/* Internal (address, port) pairs the server listens/receives at. */
#define INT_IP4         "127.0.0.2"
#define INT_IP4_V6      "::ffff:127.0.0.2"
#define INT_IP6         "fd00::2"
#define INT_PORT        8008

enum server {
        SERVER_A = 0,
        SERVER_B = 1,
        MAX_SERVERS,
};

enum {
        PROG1 = 0,
        PROG2,
};

struct inet_addr {
        const char *ip;
        unsigned short port;
};

struct test {
        const char *desc;
        struct bpf_program *lookup_prog;
        struct bpf_program *reuseport_prog;
        struct bpf_map *sock_map;
        int sotype;
        struct inet_addr connect_to;
        struct inet_addr listen_at;
        enum server accept_on;
        bool reuseport_has_conns; /* Add a connected socket to reuseport group */
};

struct cb_opts {
        int family;
        int sotype;
        bool reuseport;
};

static __u32 duration;          /* for CHECK macro */

static bool is_ipv6(const char *ip)
{
        return !!strchr(ip, ':');
}

static int attach_reuseport(int sock_fd, struct bpf_program *reuseport_prog)
{
        int err, prog_fd;

        prog_fd = bpf_program__fd(reuseport_prog);
        if (prog_fd < 0) {
                errno = -prog_fd;
                return -1;
        }

        err = setsockopt(sock_fd, SOL_SOCKET, SO_ATTACH_REUSEPORT_EBPF,
                         &prog_fd, sizeof(prog_fd));
        if (err)
                return -1;

        return 0;
}

static int setsockopts(int fd, void *opts)
{
        struct cb_opts *co = (struct cb_opts *)opts;
        const int one = 1;
        int err = 0;

        /* Enabled for UDPv6 sockets for IPv4-mapped IPv6 to work. */
        if (co->sotype == SOCK_DGRAM) {
                err = setsockopt(fd, SOL_IP, IP_RECVORIGDSTADDR, &one,
                                 sizeof(one));
                if (CHECK(err, "setsockopt(IP_RECVORIGDSTADDR)", "failed\n")) {
                        log_err("failed to enable IP_RECVORIGDSTADDR");
                        goto fail;
                }
        }

        if (co->sotype == SOCK_DGRAM && co->family == AF_INET6) {
                err = setsockopt(fd, SOL_IPV6, IPV6_RECVORIGDSTADDR, &one,
                                 sizeof(one));
                if (CHECK(err, "setsockopt(IPV6_RECVORIGDSTADDR)", "failed\n")) {
                        log_err("failed to enable IPV6_RECVORIGDSTADDR");
                        goto fail;
                }
        }

        if (co->sotype == SOCK_STREAM) {
                err = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one,
                                 sizeof(one));
                if (CHECK(err, "setsockopt(SO_REUSEADDR)", "failed\n")) {
                        log_err("failed to enable SO_REUSEADDR");
                        goto fail;
                }
        }

        if (co->reuseport) {
                err = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &one,
                                 sizeof(one));
                if (CHECK(err, "setsockopt(SO_REUSEPORT)", "failed\n")) {
                        log_err("failed to enable SO_REUSEPORT");
                        goto fail;
                }
        }

fail:
        return err;
}

static int make_server(int sotype, const char *ip, int port,
                       struct bpf_program *reuseport_prog)
{
        struct cb_opts cb_opts = {
                .family = is_ipv6(ip) ? AF_INET6 : AF_INET,
                .sotype = sotype,
                .reuseport = reuseport_prog,
        };
        struct network_helper_opts opts = {
                .backlog        = SOMAXCONN,
                .post_socket_cb = setsockopts,
                .cb_opts        = &cb_opts,
        };
        int err, fd;

        fd = start_server_str(cb_opts.family, sotype, ip, port, &opts);
        if (!ASSERT_OK_FD(fd, "start_server_str"))
                return -1;

        /* Late attach reuseport prog so we can have one init path */
        if (reuseport_prog) {
                err = attach_reuseport(fd, reuseport_prog);
                if (CHECK(err, "attach_reuseport", "failed\n")) {
                        log_err("failed to attach reuseport prog");
                        goto fail;
                }
        }

        return fd;
fail:
        close(fd);
        return -1;
}

static __u64 socket_cookie(int fd)
{
        __u64 cookie;
        socklen_t cookie_len = sizeof(cookie);

        if (CHECK(getsockopt(fd, SOL_SOCKET, SO_COOKIE, &cookie, &cookie_len) < 0,
                  "getsockopt(SO_COOKIE)", "%s\n", strerror(errno)))
                return 0;
        return cookie;
}

static int fill_sk_lookup_ctx(struct bpf_sk_lookup *ctx, const char *local_ip, __u16 local_port,
                              const char *remote_ip, __u16 remote_port)
{
        void *local, *remote;
        int err;

        memset(ctx, 0, sizeof(*ctx));
        ctx->local_port = local_port;
        ctx->remote_port = htons(remote_port);

        if (is_ipv6(local_ip)) {
                ctx->family = AF_INET6;
                local = &ctx->local_ip6[0];
                remote = &ctx->remote_ip6[0];
        } else {
                ctx->family = AF_INET;
                local = &ctx->local_ip4;
                remote = &ctx->remote_ip4;
        }

        err = inet_pton(ctx->family, local_ip, local);
        if (CHECK(err != 1, "inet_pton", "local_ip failed\n"))
                return 1;

        err = inet_pton(ctx->family, remote_ip, remote);
        if (CHECK(err != 1, "inet_pton", "remote_ip failed\n"))
                return 1;

        return 0;
}

static int send_byte(int fd)
{
        ssize_t n;

        errno = 0;
        n = send(fd, "a", 1, 0);
        if (CHECK(n <= 0, "send_byte", "send")) {
                log_err("failed/partial send");
                return -1;
        }
        return 0;
}

static int recv_byte(int fd)
{
        char buf[1];
        ssize_t n;

        n = recv(fd, buf, sizeof(buf), 0);
        if (CHECK(n <= 0, "recv_byte", "recv")) {
                log_err("failed/partial recv");
                return -1;
        }
        return 0;
}

static int tcp_recv_send(int server_fd)
{
        char buf[1];
        int ret, fd;
        ssize_t n;

        fd = accept(server_fd, NULL, NULL);
        if (CHECK(fd < 0, "accept", "failed\n")) {
                log_err("failed to accept");
                return -1;
        }

        n = recv(fd, buf, sizeof(buf), 0);
        if (CHECK(n <= 0, "recv", "failed\n")) {
                log_err("failed/partial recv");
                ret = -1;
                goto close;
        }

        n = send(fd, buf, n, 0);
        if (CHECK(n <= 0, "send", "failed\n")) {
                log_err("failed/partial send");
                ret = -1;
                goto close;
        }

        ret = 0;
close:
        close(fd);
        return ret;
}

static void v4_to_v6(struct sockaddr_storage *ss)
{
        struct sockaddr_in6 *v6 = (struct sockaddr_in6 *)ss;
        struct sockaddr_in v4 = *(struct sockaddr_in *)ss;

        v6->sin6_family = AF_INET6;
        v6->sin6_port = v4.sin_port;
        v6->sin6_addr.s6_addr[10] = 0xff;
        v6->sin6_addr.s6_addr[11] = 0xff;
        memcpy(&v6->sin6_addr.s6_addr[12], &v4.sin_addr.s_addr, 4);
        memset(&v6->sin6_addr.s6_addr[0], 0, 10);
}

static int udp_recv_send(int server_fd)
{
        char cmsg_buf[CMSG_SPACE(sizeof(struct sockaddr_storage))];
        struct sockaddr_storage _src_addr = { 0 };
        struct sockaddr_storage *src_addr = &_src_addr;
        struct sockaddr_storage *dst_addr = NULL;
        struct msghdr msg = { 0 };
        struct iovec iov = { 0 };
        struct cmsghdr *cm;
        char buf[1];
        int ret, fd;
        ssize_t n;

        iov.iov_base = buf;
        iov.iov_len = sizeof(buf);

        msg.msg_name = src_addr;
        msg.msg_namelen = sizeof(*src_addr);
        msg.msg_iov = &iov;
        msg.msg_iovlen = 1;
        msg.msg_control = cmsg_buf;
        msg.msg_controllen = sizeof(cmsg_buf);

        errno = 0;
        n = recvmsg(server_fd, &msg, 0);
        if (CHECK(n <= 0, "recvmsg", "failed\n")) {
                log_err("failed to receive");
                return -1;
        }
        if (CHECK(msg.msg_flags & MSG_CTRUNC, "recvmsg", "truncated cmsg\n"))
                return -1;

        for (cm = CMSG_FIRSTHDR(&msg); cm; cm = CMSG_NXTHDR(&msg, cm)) {
                if ((cm->cmsg_level == SOL_IP &&
                     cm->cmsg_type == IP_ORIGDSTADDR) ||
                    (cm->cmsg_level == SOL_IPV6 &&
                     cm->cmsg_type == IPV6_ORIGDSTADDR)) {
                        dst_addr = (struct sockaddr_storage *)CMSG_DATA(cm);
                        break;
                }
                log_err("warning: ignored cmsg at level %d type %d",
                        cm->cmsg_level, cm->cmsg_type);
        }
        if (CHECK(!dst_addr, "recvmsg", "missing ORIGDSTADDR\n"))
                return -1;

        /* Server socket bound to IPv4-mapped IPv6 address */
        if (src_addr->ss_family == AF_INET6 &&
            dst_addr->ss_family == AF_INET) {
                v4_to_v6(dst_addr);
        }

        /* Reply from original destination address. */
        fd = start_server_addr(SOCK_DGRAM, dst_addr, sizeof(*dst_addr), NULL);
        if (!ASSERT_OK_FD(fd, "start_server_addr")) {
                log_err("failed to create tx socket");
                return -1;
        }

        msg.msg_control = NULL;
        msg.msg_controllen = 0;
        n = sendmsg(fd, &msg, 0);
        if (CHECK(n <= 0, "sendmsg", "failed\n")) {
                log_err("failed to send echo reply");
                ret = -1;
                goto out;
        }

        ret = 0;
out:
        close(fd);
        return ret;
}

static int tcp_echo_test(int client_fd, int server_fd)
{
        int err;

        err = send_byte(client_fd);
        if (err)
                return -1;
        err = tcp_recv_send(server_fd);
        if (err)
                return -1;
        err = recv_byte(client_fd);
        if (err)
                return -1;

        return 0;
}

static int udp_echo_test(int client_fd, int server_fd)
{
        int err;

        err = send_byte(client_fd);
        if (err)
                return -1;
        err = udp_recv_send(server_fd);
        if (err)
                return -1;
        err = recv_byte(client_fd);
        if (err)
                return -1;

        return 0;
}

static struct bpf_link *attach_lookup_prog(struct bpf_program *prog)
{
        struct bpf_link *link;
        int net_fd;

        net_fd = open("/proc/self/ns/net", O_RDONLY);
        if (CHECK(net_fd < 0, "open", "failed\n")) {
                log_err("failed to open /proc/self/ns/net");
                return NULL;
        }

        link = bpf_program__attach_netns(prog, net_fd);
        if (!ASSERT_OK_PTR(link, "bpf_program__attach_netns")) {
                errno = -PTR_ERR(link);
                log_err("failed to attach program '%s' to netns",
                        bpf_program__name(prog));
                link = NULL;
        }

        close(net_fd);
        return link;
}

static int update_lookup_map(struct bpf_map *map, int index, int sock_fd)
{
        int err, map_fd;
        uint64_t value;

        map_fd = bpf_map__fd(map);
        if (CHECK(map_fd < 0, "bpf_map__fd", "failed\n")) {
                errno = -map_fd;
                log_err("failed to get map FD");
                return -1;
        }

        value = (uint64_t)sock_fd;
        err = bpf_map_update_elem(map_fd, &index, &value, BPF_NOEXIST);
        if (CHECK(err, "bpf_map_update_elem", "failed\n")) {
                log_err("failed to update redir_map @ %d", index);
                return -1;
        }

        return 0;
}

static void query_lookup_prog(struct test_sk_lookup *skel)
{
        struct bpf_link *link[3] = {};
        struct bpf_link_info info;
        __u32 attach_flags = 0;
        __u32 prog_ids[3] = {};
        __u32 prog_cnt = 3;
        __u32 prog_id;
        int net_fd;
        int err;

        net_fd = open("/proc/self/ns/net", O_RDONLY);
        if (CHECK(net_fd < 0, "open", "failed\n")) {
                log_err("failed to open /proc/self/ns/net");
                return;
        }

        link[0] = attach_lookup_prog(skel->progs.lookup_pass);
        if (!link[0])
                goto close;
        link[1] = attach_lookup_prog(skel->progs.lookup_pass);
        if (!link[1])
                goto detach;
        link[2] = attach_lookup_prog(skel->progs.lookup_drop);
        if (!link[2])
                goto detach;

        err = bpf_prog_query(net_fd, BPF_SK_LOOKUP, 0 /* query flags */,
                             &attach_flags, prog_ids, &prog_cnt);
        if (CHECK(err, "bpf_prog_query", "failed\n")) {
                log_err("failed to query lookup prog");
                goto detach;
        }

        errno = 0;
        if (CHECK(attach_flags != 0, "bpf_prog_query",
                  "wrong attach_flags on query: %u", attach_flags))
                goto detach;
        if (CHECK(prog_cnt != 3, "bpf_prog_query",
                  "wrong program count on query: %u", prog_cnt))
                goto detach;
        prog_id = link_info_prog_id(link[0], &info);
        CHECK(prog_ids[0] != prog_id, "bpf_prog_query",
              "invalid program #0 id on query: %u != %u\n",
              prog_ids[0], prog_id);
        CHECK(info.netns.netns_ino == 0, "netns_ino",
              "unexpected netns_ino: %u\n", info.netns.netns_ino);
        prog_id = link_info_prog_id(link[1], &info);
        CHECK(prog_ids[1] != prog_id, "bpf_prog_query",
              "invalid program #1 id on query: %u != %u\n",
              prog_ids[1], prog_id);
        CHECK(info.netns.netns_ino == 0, "netns_ino",
              "unexpected netns_ino: %u\n", info.netns.netns_ino);
        prog_id = link_info_prog_id(link[2], &info);
        CHECK(prog_ids[2] != prog_id, "bpf_prog_query",
              "invalid program #2 id on query: %u != %u\n",
              prog_ids[2], prog_id);
        CHECK(info.netns.netns_ino == 0, "netns_ino",
              "unexpected netns_ino: %u\n", info.netns.netns_ino);

        err = bpf_link__detach(link[0]);
        if (CHECK(err, "link_detach", "failed %d\n", err))
                goto detach;

        /* prog id is still there, but netns_ino is zeroed out */
        prog_id = link_info_prog_id(link[0], &info);
        CHECK(prog_ids[0] != prog_id, "bpf_prog_query",
              "invalid program #0 id on query: %u != %u\n",
              prog_ids[0], prog_id);
        CHECK(info.netns.netns_ino != 0, "netns_ino",
              "unexpected netns_ino: %u\n", info.netns.netns_ino);

detach:
        if (link[2])
                bpf_link__destroy(link[2]);
        if (link[1])
                bpf_link__destroy(link[1]);
        if (link[0])
                bpf_link__destroy(link[0]);
close:
        close(net_fd);
}

static void run_lookup_prog(const struct test *t)
{
        int server_fds[] = { [0 ... MAX_SERVERS - 1] = -1 };
        int client_fd, reuse_conn_fd = -1;
        struct bpf_link *lookup_link;
        int i, err;

        lookup_link = attach_lookup_prog(t->lookup_prog);
        if (!lookup_link)
                return;

        for (i = 0; i < ARRAY_SIZE(server_fds); i++) {
                server_fds[i] = make_server(t->sotype, t->listen_at.ip,
                                            t->listen_at.port,
                                            t->reuseport_prog);
                if (server_fds[i] < 0)
                        goto close;

                err = update_lookup_map(t->sock_map, i, server_fds[i]);
                if (err)
                        goto close;

                /* want just one server for non-reuseport test */
                if (!t->reuseport_prog)
                        break;
        }

        /* Regular UDP socket lookup with reuseport behaves
         * differently when reuseport group contains connected
         * sockets. Check that adding a connected UDP socket to the
         * reuseport group does not affect how reuseport works with
         * BPF socket lookup.
         */
        if (t->reuseport_has_conns) {
                /* Add an extra socket to reuseport group */
                reuse_conn_fd = make_server(t->sotype, t->listen_at.ip,
                                            t->listen_at.port,
                                            t->reuseport_prog);
                if (reuse_conn_fd < 0)
                        goto close;

                 /* Connect the extra socket to itself */
                err = connect_fd_to_fd(reuse_conn_fd, reuse_conn_fd, 0);
                if (!ASSERT_OK(err, "connect_fd_to_fd"))
                        goto close;
        }

        client_fd = connect_to_addr_str(is_ipv6(t->connect_to.ip) ? AF_INET6 : AF_INET,
                                        t->sotype, t->connect_to.ip, t->connect_to.port, NULL);
        if (!ASSERT_OK_FD(client_fd, "connect_to_addr_str"))
                goto close;

        if (t->sotype == SOCK_STREAM)
                tcp_echo_test(client_fd, server_fds[t->accept_on]);
        else
                udp_echo_test(client_fd, server_fds[t->accept_on]);

        close(client_fd);
close:
        if (reuse_conn_fd != -1)
                close(reuse_conn_fd);
        for (i = 0; i < ARRAY_SIZE(server_fds); i++) {
                if (server_fds[i] != -1)
                        close(server_fds[i]);
        }
        bpf_link__destroy(lookup_link);
}

static void test_redirect_lookup(struct test_sk_lookup *skel)
{
        const struct test tests[] = {
                {
                        .desc           = "TCP IPv4 redir port",
                        .lookup_prog    = skel->progs.redir_port,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { EXT_IP4, INT_PORT },
                },
                {
                        .desc           = "TCP IPv4 redir addr",
                        .lookup_prog    = skel->progs.redir_ip4,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { INT_IP4, EXT_PORT },
                },
                {
                        .desc           = "TCP IPv4 redir with reuseport",
                        .lookup_prog    = skel->progs.select_sock_a,
                        .reuseport_prog = skel->progs.select_sock_b,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { INT_IP4, INT_PORT },
                        .accept_on      = SERVER_B,
                },
                {
                        .desc           = "TCP IPv4 redir skip reuseport",
                        .lookup_prog    = skel->progs.select_sock_a_no_reuseport,
                        .reuseport_prog = skel->progs.select_sock_b,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { INT_IP4, INT_PORT },
                        .accept_on      = SERVER_A,
                },
                {
                        .desc           = "TCP IPv6 redir port",
                        .lookup_prog    = skel->progs.redir_port,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { EXT_IP6, INT_PORT },
                },
                {
                        .desc           = "TCP IPv6 redir addr",
                        .lookup_prog    = skel->progs.redir_ip6,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { INT_IP6, EXT_PORT },
                },
                {
                        .desc           = "TCP IPv4->IPv6 redir port",
                        .lookup_prog    = skel->progs.redir_port,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { INT_IP4_V6, INT_PORT },
                },
                {
                        .desc           = "TCP IPv6 redir with reuseport",
                        .lookup_prog    = skel->progs.select_sock_a,
                        .reuseport_prog = skel->progs.select_sock_b,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { INT_IP6, INT_PORT },
                        .accept_on      = SERVER_B,
                },
                {
                        .desc           = "TCP IPv6 redir skip reuseport",
                        .lookup_prog    = skel->progs.select_sock_a_no_reuseport,
                        .reuseport_prog = skel->progs.select_sock_b,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { INT_IP6, INT_PORT },
                        .accept_on      = SERVER_A,
                },
                {
                        .desc           = "UDP IPv4 redir port",
                        .lookup_prog    = skel->progs.redir_port,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { EXT_IP4, INT_PORT },
                },
                {
                        .desc           = "UDP IPv4 redir addr",
                        .lookup_prog    = skel->progs.redir_ip4,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { INT_IP4, EXT_PORT },
                },
                {
                        .desc           = "UDP IPv4 redir with reuseport",
                        .lookup_prog    = skel->progs.select_sock_a,
                        .reuseport_prog = skel->progs.select_sock_b,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { INT_IP4, INT_PORT },
                        .accept_on      = SERVER_B,
                },
                {
                        .desc           = "UDP IPv4 redir and reuseport with conns",
                        .lookup_prog    = skel->progs.select_sock_a,
                        .reuseport_prog = skel->progs.select_sock_b,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { INT_IP4, INT_PORT },
                        .accept_on      = SERVER_B,
                        .reuseport_has_conns = true,
                },
                {
                        .desc           = "UDP IPv4 redir skip reuseport",
                        .lookup_prog    = skel->progs.select_sock_a_no_reuseport,
                        .reuseport_prog = skel->progs.select_sock_b,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { INT_IP4, INT_PORT },
                        .accept_on      = SERVER_A,
                },
                {
                        .desc           = "UDP IPv6 redir port",
                        .lookup_prog    = skel->progs.redir_port,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { EXT_IP6, INT_PORT },
                },
                {
                        .desc           = "UDP IPv6 redir addr",
                        .lookup_prog    = skel->progs.redir_ip6,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { INT_IP6, EXT_PORT },
                },
                {
                        .desc           = "UDP IPv4->IPv6 redir port",
                        .lookup_prog    = skel->progs.redir_port,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_DGRAM,
                        .listen_at      = { INT_IP4_V6, INT_PORT },
                        .connect_to     = { EXT_IP4, EXT_PORT },
                },
                {
                        .desc           = "UDP IPv6 redir and reuseport",
                        .lookup_prog    = skel->progs.select_sock_a,
                        .reuseport_prog = skel->progs.select_sock_b,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { INT_IP6, INT_PORT },
                        .accept_on      = SERVER_B,
                },
                {
                        .desc           = "UDP IPv6 redir and reuseport with conns",
                        .lookup_prog    = skel->progs.select_sock_a,
                        .reuseport_prog = skel->progs.select_sock_b,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { INT_IP6, INT_PORT },
                        .accept_on      = SERVER_B,
                        .reuseport_has_conns = true,
                },
                {
                        .desc           = "UDP IPv6 redir skip reuseport",
                        .lookup_prog    = skel->progs.select_sock_a_no_reuseport,
                        .reuseport_prog = skel->progs.select_sock_b,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { INT_IP6, INT_PORT },
                        .accept_on      = SERVER_A,
                },
        };
        const struct test *t;

        for (t = tests; t < tests + ARRAY_SIZE(tests); t++) {
                if (test__start_subtest(t->desc))
                        run_lookup_prog(t);
        }
}

static void drop_on_lookup(const struct test *t)
{
        int family = is_ipv6(t->connect_to.ip) ? AF_INET6 : AF_INET;
        struct sockaddr_storage dst = {};
        int client_fd, server_fd, err;
        struct bpf_link *lookup_link;
        socklen_t len;
        ssize_t n;

        lookup_link = attach_lookup_prog(t->lookup_prog);
        if (!lookup_link)
                return;

        server_fd = make_server(t->sotype, t->listen_at.ip, t->listen_at.port,
                                t->reuseport_prog);
        if (server_fd < 0)
                goto detach;

        client_fd = client_socket(family, t->sotype, NULL);
        if (!ASSERT_OK_FD(client_fd, "client_socket"))
                goto close_srv;

        err = make_sockaddr(family, t->connect_to.ip, t->connect_to.port, &dst, &len);
        if (!ASSERT_OK(err, "make_sockaddr"))
                goto close_all;
        err = connect(client_fd, (void *)&dst, len);
        if (t->sotype == SOCK_DGRAM) {
                err = send_byte(client_fd);
                if (err)
                        goto close_all;

                /* Read out asynchronous error */
                n = recv(client_fd, NULL, 0, 0);
                err = n == -1;
        }
        if (CHECK(!err || errno != ECONNREFUSED, "connect",
                  "unexpected success or error\n"))
                log_err("expected ECONNREFUSED on connect");

close_all:
        close(client_fd);
close_srv:
        close(server_fd);
detach:
        bpf_link__destroy(lookup_link);
}

static void test_drop_on_lookup(struct test_sk_lookup *skel)
{
        const struct test tests[] = {
                {
                        .desc           = "TCP IPv4 drop on lookup",
                        .lookup_prog    = skel->progs.lookup_drop,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { EXT_IP4, EXT_PORT },
                },
                {
                        .desc           = "TCP IPv6 drop on lookup",
                        .lookup_prog    = skel->progs.lookup_drop,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { EXT_IP6, EXT_PORT },
                },
                {
                        .desc           = "UDP IPv4 drop on lookup",
                        .lookup_prog    = skel->progs.lookup_drop,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { EXT_IP4, EXT_PORT },
                },
                {
                        .desc           = "UDP IPv6 drop on lookup",
                        .lookup_prog    = skel->progs.lookup_drop,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { EXT_IP6, INT_PORT },
                },
                /* The program will drop on success, meaning that the ifindex
                 * was 1.
                 */
                {
                        .desc           = "TCP IPv4 drop on valid ifindex",
                        .lookup_prog    = skel->progs.check_ifindex,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { EXT_IP4, EXT_PORT },
                },
                {
                        .desc           = "TCP IPv6 drop on valid ifindex",
                        .lookup_prog    = skel->progs.check_ifindex,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { EXT_IP6, EXT_PORT },
                },
                {
                        .desc           = "UDP IPv4 drop on valid ifindex",
                        .lookup_prog    = skel->progs.check_ifindex,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { EXT_IP4, EXT_PORT },
                },
                {
                        .desc           = "UDP IPv6 drop on valid ifindex",
                        .lookup_prog    = skel->progs.check_ifindex,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { EXT_IP6, EXT_PORT },
                },
        };
        const struct test *t;

        for (t = tests; t < tests + ARRAY_SIZE(tests); t++) {
                if (test__start_subtest(t->desc))
                        drop_on_lookup(t);
        }
}

static void drop_on_reuseport(const struct test *t)
{
        int family = is_ipv6(t->connect_to.ip) ? AF_INET6 : AF_INET;
        struct sockaddr_storage dst = { 0 };
        int client, server1, server2, err;
        struct bpf_link *lookup_link;
        socklen_t len;
        ssize_t n;

        lookup_link = attach_lookup_prog(t->lookup_prog);
        if (!lookup_link)
                return;

        server1 = make_server(t->sotype, t->listen_at.ip, t->listen_at.port,
                              t->reuseport_prog);
        if (server1 < 0)
                goto detach;

        err = update_lookup_map(t->sock_map, SERVER_A, server1);
        if (err)
                goto close_srv1;

        /* second server on destination address we should never reach */
        server2 = make_server(t->sotype, t->connect_to.ip, t->connect_to.port,
                              NULL /* reuseport prog */);
        if (server2 < 0)
                goto close_srv1;

        client = client_socket(family, t->sotype, NULL);
        if (!ASSERT_OK_FD(client, "client_socket"))
                goto close_srv2;

        err = make_sockaddr(family, t->connect_to.ip, t->connect_to.port, &dst, &len);
        if (!ASSERT_OK(err, "make_sockaddr"))
                goto close_all;
        err = connect(client, (void *)&dst, len);
        if (t->sotype == SOCK_DGRAM) {
                err = send_byte(client);
                if (err)
                        goto close_all;

                /* Read out asynchronous error */
                n = recv(client, NULL, 0, 0);
                err = n == -1;
        }
        if (CHECK(!err || errno != ECONNREFUSED, "connect",
                  "unexpected success or error\n"))
                log_err("expected ECONNREFUSED on connect");

close_all:
        close(client);
close_srv2:
        close(server2);
close_srv1:
        close(server1);
detach:
        bpf_link__destroy(lookup_link);
}

static void test_drop_on_reuseport(struct test_sk_lookup *skel)
{
        const struct test tests[] = {
                {
                        .desc           = "TCP IPv4 drop on reuseport",
                        .lookup_prog    = skel->progs.select_sock_a,
                        .reuseport_prog = skel->progs.reuseport_drop,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { INT_IP4, INT_PORT },
                },
                {
                        .desc           = "TCP IPv6 drop on reuseport",
                        .lookup_prog    = skel->progs.select_sock_a,
                        .reuseport_prog = skel->progs.reuseport_drop,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { INT_IP6, INT_PORT },
                },
                {
                        .desc           = "UDP IPv4 drop on reuseport",
                        .lookup_prog    = skel->progs.select_sock_a,
                        .reuseport_prog = skel->progs.reuseport_drop,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_DGRAM,
                        .connect_to     = { EXT_IP4, EXT_PORT },
                        .listen_at      = { INT_IP4, INT_PORT },
                },
                {
                        .desc           = "TCP IPv6 drop on reuseport",
                        .lookup_prog    = skel->progs.select_sock_a,
                        .reuseport_prog = skel->progs.reuseport_drop,
                        .sock_map       = skel->maps.redir_map,
                        .sotype         = SOCK_STREAM,
                        .connect_to     = { EXT_IP6, EXT_PORT },
                        .listen_at      = { INT_IP6, INT_PORT },
                },
        };
        const struct test *t;

        for (t = tests; t < tests + ARRAY_SIZE(tests); t++) {
                if (test__start_subtest(t->desc))
                        drop_on_reuseport(t);
        }
}

static void run_sk_assign(struct test_sk_lookup *skel,
                          struct bpf_program *lookup_prog,
                          const char *remote_ip, const char *local_ip)
{
        int server_fds[] = { [0 ... MAX_SERVERS - 1] = -1 };
        struct bpf_sk_lookup ctx;
        __u64 server_cookie;
        int i, err;

        DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts,
                .ctx_in = &ctx,
                .ctx_size_in = sizeof(ctx),
                .ctx_out = &ctx,
                .ctx_size_out = sizeof(ctx),
        );

        if (fill_sk_lookup_ctx(&ctx, local_ip, EXT_PORT, remote_ip, INT_PORT))
                return;

        ctx.protocol = IPPROTO_TCP;

        for (i = 0; i < ARRAY_SIZE(server_fds); i++) {
                server_fds[i] = make_server(SOCK_STREAM, local_ip, 0, NULL);
                if (server_fds[i] < 0)
                        goto close_servers;

                err = update_lookup_map(skel->maps.redir_map, i,
                                        server_fds[i]);
                if (err)
                        goto close_servers;
        }

        server_cookie = socket_cookie(server_fds[SERVER_B]);
        if (!server_cookie)
                return;

        err = bpf_prog_test_run_opts(bpf_program__fd(lookup_prog), &opts);
        if (CHECK(err, "test_run", "failed with error %d\n", errno))
                goto close_servers;

        if (CHECK(ctx.cookie == 0, "ctx.cookie", "no socket selected\n"))
                goto close_servers;

        CHECK(ctx.cookie != server_cookie, "ctx.cookie",
              "selected sk %llu instead of %llu\n", ctx.cookie, server_cookie);

close_servers:
        for (i = 0; i < ARRAY_SIZE(server_fds); i++) {
                if (server_fds[i] != -1)
                        close(server_fds[i]);
        }
}

static void run_sk_assign_v4(struct test_sk_lookup *skel,
                             struct bpf_program *lookup_prog)
{
        run_sk_assign(skel, lookup_prog, INT_IP4, EXT_IP4);
}

static void run_sk_assign_v6(struct test_sk_lookup *skel,
                             struct bpf_program *lookup_prog)
{
        run_sk_assign(skel, lookup_prog, INT_IP6, EXT_IP6);
}

static void run_sk_assign_connected(struct test_sk_lookup *skel,
                                    int sotype)
{
        int err, client_fd, connected_fd, server_fd;
        struct bpf_link *lookup_link;

        server_fd = make_server(sotype, EXT_IP4, EXT_PORT, NULL);
        if (server_fd < 0)
                return;

        connected_fd = connect_to_addr_str(AF_INET, sotype, EXT_IP4, EXT_PORT, NULL);
        if (!ASSERT_OK_FD(connected_fd, "connect_to_addr_str"))
                goto out_close_server;

        /* Put a connected socket in redirect map */
        err = update_lookup_map(skel->maps.redir_map, SERVER_A, connected_fd);
        if (err)
                goto out_close_connected;

        lookup_link = attach_lookup_prog(skel->progs.sk_assign_esocknosupport);
        if (!lookup_link)
                goto out_close_connected;

        /* Try to redirect TCP SYN / UDP packet to a connected socket */
        client_fd = connect_to_addr_str(AF_INET, sotype, EXT_IP4, EXT_PORT, NULL);
        if (!ASSERT_OK_FD(client_fd, "connect_to_addr_str"))
                goto out_unlink_prog;
        if (sotype == SOCK_DGRAM) {
                send_byte(client_fd);
                recv_byte(server_fd);
        }

        close(client_fd);
out_unlink_prog:
        bpf_link__destroy(lookup_link);
out_close_connected:
        close(connected_fd);
out_close_server:
        close(server_fd);
}

static void test_sk_assign_helper(struct test_sk_lookup *skel)
{
        if (test__start_subtest("sk_assign returns EEXIST"))
                run_sk_assign_v4(skel, skel->progs.sk_assign_eexist);
        if (test__start_subtest("sk_assign honors F_REPLACE"))
                run_sk_assign_v4(skel, skel->progs.sk_assign_replace_flag);
        if (test__start_subtest("sk_assign accepts NULL socket"))
                run_sk_assign_v4(skel, skel->progs.sk_assign_null);
        if (test__start_subtest("access ctx->sk"))
                run_sk_assign_v4(skel, skel->progs.access_ctx_sk);
        if (test__start_subtest("narrow access to ctx v4"))
                run_sk_assign_v4(skel, skel->progs.ctx_narrow_access);
        if (test__start_subtest("narrow access to ctx v6"))
                run_sk_assign_v6(skel, skel->progs.ctx_narrow_access);
        if (test__start_subtest("sk_assign rejects TCP established"))
                run_sk_assign_connected(skel, SOCK_STREAM);
        if (test__start_subtest("sk_assign rejects UDP connected"))
                run_sk_assign_connected(skel, SOCK_DGRAM);
}

struct test_multi_prog {
        const char *desc;
        struct bpf_program *prog1;
        struct bpf_program *prog2;
        struct bpf_map *redir_map;
        struct bpf_map *run_map;
        int expect_errno;
        struct inet_addr listen_at;
};

static void run_multi_prog_lookup(const struct test_multi_prog *t)
{
        struct sockaddr_storage dst = {};
        int map_fd, server_fd, client_fd;
        struct bpf_link *link1, *link2;
        int prog_idx, done, err;
        socklen_t len;

        map_fd = bpf_map__fd(t->run_map);

        done = 0;
        prog_idx = PROG1;
        err = bpf_map_update_elem(map_fd, &prog_idx, &done, BPF_ANY);
        if (CHECK(err, "bpf_map_update_elem", "failed\n"))
                return;
        prog_idx = PROG2;
        err = bpf_map_update_elem(map_fd, &prog_idx, &done, BPF_ANY);
        if (CHECK(err, "bpf_map_update_elem", "failed\n"))
                return;

        link1 = attach_lookup_prog(t->prog1);
        if (!link1)
                return;
        link2 = attach_lookup_prog(t->prog2);
        if (!link2)
                goto out_unlink1;

        server_fd = make_server(SOCK_STREAM, t->listen_at.ip,
                                t->listen_at.port, NULL);
        if (server_fd < 0)
                goto out_unlink2;

        err = update_lookup_map(t->redir_map, SERVER_A, server_fd);
        if (err)
                goto out_close_server;

        client_fd = client_socket(AF_INET, SOCK_STREAM, NULL);
        if (!ASSERT_OK_FD(client_fd, "client_socket"))
                goto out_close_server;

        err = make_sockaddr(AF_INET, EXT_IP4, EXT_PORT, &dst, &len);
        if (!ASSERT_OK(err, "make_sockaddr"))
                goto out_close_client;
        err = connect(client_fd, (void *)&dst, len);
        if (CHECK(err && !t->expect_errno, "connect",
                  "unexpected error %d\n", errno))
                goto out_close_client;
        if (CHECK(err && t->expect_errno && errno != t->expect_errno,
                  "connect", "unexpected error %d\n", errno))
                goto out_close_client;

        done = 0;
        prog_idx = PROG1;
        err = bpf_map_lookup_elem(map_fd, &prog_idx, &done);
        CHECK(err, "bpf_map_lookup_elem", "failed\n");
        CHECK(!done, "bpf_map_lookup_elem", "PROG1 !done\n");

        done = 0;
        prog_idx = PROG2;
        err = bpf_map_lookup_elem(map_fd, &prog_idx, &done);
        CHECK(err, "bpf_map_lookup_elem", "failed\n");
        CHECK(!done, "bpf_map_lookup_elem", "PROG2 !done\n");

out_close_client:
        close(client_fd);
out_close_server:
        close(server_fd);
out_unlink2:
        bpf_link__destroy(link2);
out_unlink1:
        bpf_link__destroy(link1);
}

static void test_multi_prog_lookup(struct test_sk_lookup *skel)
{
        struct test_multi_prog tests[] = {
                {
                        .desc           = "multi prog - pass, pass",
                        .prog1          = skel->progs.multi_prog_pass1,
                        .prog2          = skel->progs.multi_prog_pass2,
                        .listen_at      = { EXT_IP4, EXT_PORT },
                },
                {
                        .desc           = "multi prog - drop, drop",
                        .prog1          = skel->progs.multi_prog_drop1,
                        .prog2          = skel->progs.multi_prog_drop2,
                        .listen_at      = { EXT_IP4, EXT_PORT },
                        .expect_errno   = ECONNREFUSED,
                },
                {
                        .desc           = "multi prog - pass, drop",
                        .prog1          = skel->progs.multi_prog_pass1,
                        .prog2          = skel->progs.multi_prog_drop2,
                        .listen_at      = { EXT_IP4, EXT_PORT },
                        .expect_errno   = ECONNREFUSED,
                },
                {
                        .desc           = "multi prog - drop, pass",
                        .prog1          = skel->progs.multi_prog_drop1,
                        .prog2          = skel->progs.multi_prog_pass2,
                        .listen_at      = { EXT_IP4, EXT_PORT },
                        .expect_errno   = ECONNREFUSED,
                },
                {
                        .desc           = "multi prog - pass, redir",
                        .prog1          = skel->progs.multi_prog_pass1,
                        .prog2          = skel->progs.multi_prog_redir2,
                        .listen_at      = { INT_IP4, INT_PORT },
                },
                {
                        .desc           = "multi prog - redir, pass",
                        .prog1          = skel->progs.multi_prog_redir1,
                        .prog2          = skel->progs.multi_prog_pass2,
                        .listen_at      = { INT_IP4, INT_PORT },
                },
                {
                        .desc           = "multi prog - drop, redir",
                        .prog1          = skel->progs.multi_prog_drop1,
                        .prog2          = skel->progs.multi_prog_redir2,
                        .listen_at      = { INT_IP4, INT_PORT },
                },
                {
                        .desc           = "multi prog - redir, drop",
                        .prog1          = skel->progs.multi_prog_redir1,
                        .prog2          = skel->progs.multi_prog_drop2,
                        .listen_at      = { INT_IP4, INT_PORT },
                },
                {
                        .desc           = "multi prog - redir, redir",
                        .prog1          = skel->progs.multi_prog_redir1,
                        .prog2          = skel->progs.multi_prog_redir2,
                        .listen_at      = { INT_IP4, INT_PORT },
                },
        };
        struct test_multi_prog *t;

        for (t = tests; t < tests + ARRAY_SIZE(tests); t++) {
                t->redir_map = skel->maps.redir_map;
                t->run_map = skel->maps.run_map;
                if (test__start_subtest(t->desc))
                        run_multi_prog_lookup(t);
        }
}

static void run_tests(struct test_sk_lookup *skel)
{
        if (test__start_subtest("query lookup prog"))
                query_lookup_prog(skel);
        test_redirect_lookup(skel);
        test_drop_on_lookup(skel);
        test_drop_on_reuseport(skel);
        test_sk_assign_helper(skel);
        test_multi_prog_lookup(skel);
}

static int switch_netns(void)
{
        static const char * const setup_script[] = {
                "ip -6 addr add dev lo " EXT_IP6 "/128",
                "ip -6 addr add dev lo " INT_IP6 "/128",
                "ip link set dev lo up",
                NULL,
        };
        const char * const *cmd;
        int err;

        err = unshare(CLONE_NEWNET);
        if (CHECK(err, "unshare", "failed\n")) {
                log_err("unshare(CLONE_NEWNET)");
                return -1;
        }

        for (cmd = setup_script; *cmd; cmd++) {
                err = system(*cmd);
                if (CHECK(err, "system", "failed\n")) {
                        log_err("system(%s)", *cmd);
                        return -1;
                }
        }

        return 0;
}

void test_sk_lookup(void)
{
        struct test_sk_lookup *skel;
        int err;

        err = switch_netns();
        if (err)
                return;

        skel = test_sk_lookup__open_and_load();
        if (CHECK(!skel, "skel open_and_load", "failed\n"))
                return;

        run_tests(skel);

        test_sk_lookup__destroy(skel);
}