/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2026 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 <arpa/inet.h>
#include <netinet/ip.h>
#include <net/if.h>
#include <errno.h>
#include <stdlib.h>

#include <atf-c.h>

#define PROT1           253 /* RFC3692 */
#define PROT2           254 /* RFC3692 */
#define ADDR1           { htonl(0xc0000202) }   /* RFC5737 */
#define ADDR2           { htonl(0xc0000203) }   /* RFC5737 */
#define WILD            { htonl(INADDR_ANY) }
#define LOOP(x)         { htonl(INADDR_LOOPBACK + (x)) }
#define MULT(x)         { htonl(INADDR_UNSPEC_GROUP + (x)) }

static int
rawsender(bool mcast)
{
        int s;

        ATF_REQUIRE((s = socket(PF_INET, SOCK_RAW, 0)) != -1);
        ATF_REQUIRE(setsockopt(s, IPPROTO_IP, IP_HDRINCL, &(int){1},
            sizeof(int)) == 0);
        /*
         * Make sending socket connected.  The socket API requires connected
         * status to use send(2), even with IP_HDRINCL.
         */
        ATF_REQUIRE(connect(s,
            (struct sockaddr *)&(struct sockaddr_in){
                .sin_family = AF_INET,
                .sin_len = sizeof(struct sockaddr_in),
                .sin_addr = { htonl(INADDR_ANY) },
            }, sizeof(struct sockaddr_in)) == 0);

        if (mcast)
                ATF_REQUIRE(setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
                    &(struct ip_mreqn){
                        .imr_ifindex = if_nametoindex("lo0"),
                    }, sizeof(struct ip_mreqn)) == 0);

        return (s);
}

/*
 * The 'input' test exercises logic of rip_input().  The best documentation
 * for raw socket input behavior is collected in Stevens's UNIX Network
 * Programming, Section 28.4.  We create several sockets, with different
 * remote and local bindings, as well as a socket with multicast membership
 * and then we send different packets and see which sockets received their
 * copy.
 * The table tests[] describes our expectations.
 */
ATF_TC_WITHOUT_HEAD(input);
ATF_TC_BODY(input, tc)
{
        static const struct rcvr {
                struct in_addr laddr, faddr, maddr;
                uint8_t proto;
        } rcvrs[] = {
                { WILD,    WILD,    WILD,    0 },
                { WILD,    WILD,    WILD,    PROT1 },
                { LOOP(0), WILD,    WILD,    0 },
                { LOOP(0), WILD,    WILD,    PROT1 },
                { LOOP(1), WILD,    WILD,    0 },
                { LOOP(1), WILD,    WILD,    PROT1 },
                { LOOP(0), LOOP(2), WILD,    0 },
                { LOOP(0), LOOP(2), WILD,    PROT1 },
                { LOOP(0), LOOP(3), WILD,    0 },
                { LOOP(0), LOOP(3), WILD,    PROT1 },
                { LOOP(1), LOOP(3), WILD,    0 },
                { LOOP(1), LOOP(3), WILD,    PROT1 },
                { WILD,    WILD,    MULT(1), 0 },
        };
        static const struct test {
                struct in_addr src, dst;
                uint8_t proto;
                bool results[nitems(rcvrs)];
        } tests[] = {
#define x true
#define o false
                { LOOP(2), LOOP(0), PROT1,
                  { x, x, x, x, o, o, x, x, o, o, o, o, x } },
                { LOOP(2), LOOP(0), PROT2,
                  { x, o, x, o, o, o, x, o, o, o, o, o, x } },
                { LOOP(3), LOOP(0), PROT1,
                  { x, x, x, x, o, o, o, o, x, x, o, o, x } },
                { LOOP(3), LOOP(0), PROT2,
                  { x, o, x, o, o, o, o, o, x, o, o, o, x } },
                { LOOP(2), LOOP(1), PROT1,
                  { x, x, o, o, x, x, o, o, o, o, o, o, x } },
                { LOOP(2), LOOP(1), PROT2,
                  { x, o, o, o, x, o, o, o, o, o, o, o, x } },
                { LOOP(3), LOOP(1), PROT1,
                  { x, x, o, o, x, x, o, o, o, o, x, x, x } },
                { LOOP(3), LOOP(1), PROT2,
                  { x, o, o, o, x, o, o, o, o, o, x, o, x } },
                { LOOP(3), MULT(1), PROT1,
                  { x, x, o, o, o, o, o, o, o, o, o, o, x } },
                { LOOP(3), MULT(2), PROT1,
                  { x, x, o, o, o, o, o, o, o, o, o, o, o } },
#undef x
#undef o
        };
        struct pkt {
                struct ip ip;
                char payload[100];
        } __packed pkt = {
                .ip.ip_v = IPVERSION,
                .ip.ip_hl = sizeof(struct ip) >> 2,
                .ip.ip_len = htons(sizeof(struct pkt)),
                .ip.ip_ttl = 16,
        };
        struct sockaddr_in sin = {
                .sin_family = AF_INET,
                .sin_len = sizeof(sin),
        };
        struct ip_mreqn mreqn = {
                .imr_ifindex = if_nametoindex("lo0"),
        };
        int r[nitems(rcvrs)];
        int s;

        /*
         * This XXX to be removed when kyua provides generic framework for
         * constructing test jail environments.
         */
        system("/sbin/ifconfig lo0 127.0.0.1/32");
        system("/sbin/ifconfig lo0 127.0.0.2/32 alias");

        for (u_int i = 0; i < nitems(rcvrs); i++) {
                /*
                 * To avoid a race between send(2) and packet queueing in
                 * netisr(9) and our recv(2), set the very first receiver
                 * socket to blocking mode.  Note in the above table that first
                 * receiver is supposed to receive something in every test.
                 */
                ATF_REQUIRE((r[i] = socket(PF_INET, SOCK_RAW |
                    (i != 0 ? SOCK_NONBLOCK : 0),
                    rcvrs[i].proto)) != -1);
                if (rcvrs[i].laddr.s_addr != htonl(INADDR_ANY)) {
                        sin.sin_addr = rcvrs[i].laddr;
                        ATF_REQUIRE(bind(r[i], (struct sockaddr *)&sin,
                            sizeof(sin)) == 0);
                }
                if (rcvrs[i].faddr.s_addr != htonl(INADDR_ANY)) {
                        sin.sin_addr = rcvrs[i].faddr;
                        ATF_REQUIRE(connect(r[i], (struct sockaddr *)&sin,
                            sizeof(sin)) == 0);
                }
                if (rcvrs[i].maddr.s_addr != htonl(INADDR_ANY)) {
                        mreqn.imr_multiaddr = rcvrs[i].maddr;
                        ATF_REQUIRE(setsockopt(r[i], IPPROTO_IP,
                            IP_ADD_MEMBERSHIP, &mreqn, sizeof(mreqn)) == 0);
                }
        }

        /*
         * Force multicast interface for the sending socket to be able to
         * send to MULT(x) destinations.
         */
        s = rawsender(true);

        for (u_int i = 0; i < nitems(tests); i++) {
                arc4random_buf(&pkt.payload, sizeof(pkt.payload));
                pkt.ip.ip_src = tests[i].src;
                pkt.ip.ip_dst = tests[i].dst;
                pkt.ip.ip_p = tests[i].proto;
                ATF_REQUIRE(send(s, &pkt, sizeof(pkt), 0) == sizeof(pkt));
                for (u_int j = 0; j < nitems(rcvrs); j++) {
                        char buf[sizeof(pkt)];
                        char p[4][INET_ADDRSTRLEN];
                        ssize_t ss;

                        ss = recv(r[j], buf, sizeof(buf), 0);

                        ATF_REQUIRE_MSG((tests[i].results[j] == true &&
                            ss == sizeof(buf) && memcmp(buf + sizeof(struct ip),
                            pkt.payload, sizeof(pkt.payload)) == 0) ||
                            (tests[i].results[j] == false &&
                            ss == -1 && errno == EAGAIN),
                            "test #%u %s->%s %u unexpected receive of %zd "
                             "bytes errno %d on socket #%u %s->%s %u", i,
                            inet_ntop(AF_INET, &tests[i].src, p[0],
                                INET_ADDRSTRLEN),
                            inet_ntop(AF_INET, &tests[i].dst, p[1],
                                INET_ADDRSTRLEN),
                            tests[i].proto, ss, errno, j,
                            inet_ntop(AF_INET, &rcvrs[j].faddr, p[2],
                                INET_ADDRSTRLEN),
                            inet_ntop(AF_INET, &rcvrs[j].laddr, p[3],
                                INET_ADDRSTRLEN),
                            rcvrs[j].proto);
                }
        }
}

/*
 * Test input on the same socket that changes its connection status.  We send
 * packets with different sources in each iteration and check results.
 * Check that connect(INADDR_ANY) is effectively a disconnect and turns socket
 * back to receive-all mode.
 */
ATF_TC_WITHOUT_HEAD(reconnect);
ATF_TC_BODY(reconnect, tc)
{
        static const struct in_addr srcs[] = { ADDR1, ADDR2 };
        static const struct test {
                struct in_addr faddr;
                bool results[nitems(srcs)];
        } tests[] = {
                { ADDR1,        { true, false } },
                { ADDR2,        { false, true } },
                { {INADDR_ANY}, { true, true } },
        };
        struct pkt {
                struct ip ip;
                char payload[100];
        } __packed pkt = {
                .ip.ip_v = IPVERSION,
                .ip.ip_hl = sizeof(struct ip) >> 2,
                .ip.ip_len = htons(sizeof(struct pkt)),
                .ip.ip_ttl = 16,
                .ip.ip_p = PROT1,
                .ip.ip_dst = LOOP(0),
        };
        int r, s;

        /* XXX */
        system("/sbin/ifconfig lo0 127.0.0.1/32");

        ATF_REQUIRE((r = socket(PF_INET, SOCK_RAW | SOCK_NONBLOCK, 0)) != -1);
        s = rawsender(false);

        for (u_int i = 0; i < nitems(tests); i++) {
                ATF_REQUIRE(connect(r,
                    (struct sockaddr *)&(struct sockaddr_in){
                        .sin_family = AF_INET,
                        .sin_len = sizeof(struct sockaddr_in),
                        .sin_addr = tests[i].faddr,
                    }, sizeof(struct sockaddr_in)) == 0);

                for (u_int j = 0; j < nitems(srcs); j++) {
                        char buf[sizeof(pkt)];
                        char p[2][INET_ADDRSTRLEN];
                        ssize_t ss;

                        arc4random_buf(&pkt.payload, sizeof(pkt.payload));
                        pkt.ip.ip_src = srcs[j];
                        ATF_REQUIRE(send(s, &pkt, sizeof(pkt), 0) ==
                            sizeof(pkt));

                        /*
                         * The sender is a blocking socket, so we first receive
                         * from the sender and when this read returns we are
                         * guaranteed that the test socket also received the
                         * datagram.
                         */
                        ss = recv(s, buf, sizeof(buf), 0);
                        ATF_REQUIRE(ss == sizeof(buf) &&
                            memcmp(buf + sizeof(struct ip),
                            pkt.payload, sizeof(pkt.payload)) == 0);

                        ss = recv(r, buf, sizeof(buf), 0);

                        ATF_REQUIRE_MSG((tests[i].results[j] == true &&
                            ss == sizeof(buf) && memcmp(buf + sizeof(struct ip),
                            pkt.payload, sizeof(pkt.payload)) == 0) ||
                            (tests[i].results[j] == false && ss == -1 &&
                            errno == EAGAIN),
                            "test #%u src %s connect address %s unexpected "
                            "receive of %zd bytes errno %d", i,
                            inet_ntop(AF_INET, &srcs[j], p[0],
                                INET_ADDRSTRLEN),
                            inet_ntop(AF_INET, &tests[i].faddr, p[1],
                                INET_ADDRSTRLEN),
                            ss, errno);
                }
        }
}

ATF_TP_ADD_TCS(tp)
{
        ATF_TP_ADD_TC(tp, input);
        ATF_TP_ADD_TC(tp, reconnect);

        return (atf_no_error());
}