/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2025 Gleb Smirnoff <glebius@FreeBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <errno.h>
#include <ifaddrs.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <atf-c.h>

static const char buf[] = "Hello";

/* Create a UDP socket with SO_BROADCAST set. */
static int
bcastsock(void)
{
        int s;

        ATF_REQUIRE((s = socket(PF_INET, SOCK_DGRAM, 0)) > 0);
        ATF_REQUIRE(setsockopt(s, SOL_SOCKET, SO_BROADCAST, &(int){1},
            sizeof(int)) == 0);
        return (s);
}

/* Send on socket 's' with address 'to', confirm receive on 'r'. */
static void
bcastecho(int s, struct sockaddr_in *to, int r)
{
        char rbuf[sizeof(buf)];

        printf("Sending to %s\n", inet_ntoa(to->sin_addr));
        ATF_REQUIRE_MSG(sendto(s, buf, sizeof(buf), 0, (struct sockaddr *)to,
            sizeof(*to)) == sizeof(buf), "sending of broadcast failed: %d",
            errno);
        ATF_REQUIRE(recv(r, rbuf, sizeof(rbuf), 0) == sizeof(rbuf));
        ATF_REQUIRE_MSG(memcmp(buf, rbuf, sizeof(buf)) == 0,
            "failed to receive own broadcast");
}

/* Find a first broadcast capable interface and copy its broadcast address. */
static void
firstbcast(struct in_addr *out)
{
        struct ifaddrs *ifa0, *ifa;
        struct sockaddr_in sin;

        ATF_REQUIRE(getifaddrs(&ifa0) == 0);
        for (ifa = ifa0; ifa != NULL; ifa = ifa->ifa_next)
                if (ifa->ifa_addr->sa_family == AF_INET &&
                    (ifa->ifa_flags & IFF_BROADCAST))
                        break;
        if (ifa == NULL) {
                freeifaddrs(ifa0);
                atf_tc_skip("No broadcast address found");
        }
        memcpy(&sin, ifa->ifa_broadaddr, sizeof(struct sockaddr_in));
        *out = sin.sin_addr;
        freeifaddrs(ifa0);
}

/* Application sends to INADDR_BROADCAST, and this goes on the wire. */
ATF_TC(INADDR_BROADCAST);
ATF_TC_HEAD(INADDR_BROADCAST, tc)
{
        atf_tc_set_md_var(tc, "require.config", "allow_network_access");
}
ATF_TC_BODY(INADDR_BROADCAST, tc)
{
        struct sockaddr_in sin = {
                .sin_family = AF_INET,
                .sin_len = sizeof(struct sockaddr_in),
        };
        socklen_t slen = sizeof(sin);
        int l, s;

        l = bcastsock();
        ATF_REQUIRE(bind(l, (struct sockaddr *)&sin, sizeof(sin)) == 0);
        ATF_REQUIRE(getsockname(l, (struct sockaddr *)&sin, &slen) == 0);
        sin.sin_addr.s_addr = htonl(INADDR_BROADCAST);

        s = bcastsock();
        bcastecho(s, &sin, l);

        close(s);
        close(l);
}

/*
 * Application sends on broadcast address of an interface, INADDR_BROADCAST
 * goes on the wire of the selected interface.
 */
ATF_TC_WITHOUT_HEAD(IP_ONESBCAST);
ATF_TC_BODY(IP_ONESBCAST, tc)
{
        struct ifaddrs *ifa0, *ifa;
        struct sockaddr_in sin = {
                .sin_family = AF_INET,
                .sin_len = sizeof(struct sockaddr_in),
        };
        socklen_t slen = sizeof(sin);
        int s, l;
        in_port_t port;
        bool skip = true;

        s = bcastsock();
        ATF_REQUIRE(setsockopt(s, IPPROTO_IP, IP_ONESBCAST, &(int){1},
            sizeof(int)) == 0);

        l = bcastsock();
        ATF_REQUIRE(bind(l, (struct sockaddr *)&sin, sizeof(sin)) == 0);
        ATF_REQUIRE(getsockname(l, (struct sockaddr *)&sin, &slen) == 0);
        port = sin.sin_port;

        ATF_REQUIRE(getifaddrs(&ifa0) == 0);
        for (ifa = ifa0; ifa != NULL; ifa = ifa->ifa_next) {
                if (ifa->ifa_addr->sa_family != AF_INET)
                        continue;
                if (!(ifa->ifa_flags & IFF_BROADCAST))
                        continue;
                skip = false;
                memcpy(&sin, ifa->ifa_broadaddr, sizeof(struct sockaddr_in));
                sin.sin_port = port;
                bcastecho(s, &sin, l);
        }
        freeifaddrs(ifa0);
        close(s);
        close(l);
        if (skip)
                atf_tc_skip("No broadcast address found");
}

/*
 * Application sends on broadcast address of an interface, and this is what
 * goes out the wire.
 */
ATF_TC_WITHOUT_HEAD(local_broadcast);
ATF_TC_BODY(local_broadcast, tc)
{
        struct sockaddr_in sin = {
                .sin_family = AF_INET,
                .sin_len = sizeof(struct sockaddr_in),
        };
        socklen_t slen = sizeof(sin);
        int s, l;

        s = bcastsock();
        l = bcastsock();
        ATF_REQUIRE(bind(l, (struct sockaddr *)&sin, sizeof(sin)) == 0);
        ATF_REQUIRE(getsockname(l, (struct sockaddr *)&sin, &slen) == 0);
        firstbcast(&sin.sin_addr);

        bcastecho(s, &sin, l);

        close(s);
        close(l);
}

ATF_TP_ADD_TCS(tp)
{
        ATF_TP_ADD_TC(tp, INADDR_BROADCAST);
        ATF_TP_ADD_TC(tp, IP_ONESBCAST);
        ATF_TP_ADD_TC(tp, local_broadcast);

        return (atf_no_error());
}