/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2020 Mariusz Zaborski <oshogbo@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 AUTHORS 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 AUTHORS 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/cdefs.h>
#include <sys/cnv.h>
#include <sys/dnv.h>
#include <sys/nv.h>
#include <sys/socket.h>
#include <netinet/in.h>

#include <assert.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <libcasper.h>
#include <libcasper_service.h>

#include "cap_net.h"

#define CAPNET_MASK     (CAPNET_ADDR2NAME | CAPNET_NAME2ADDR    \
    CAPNET_DEPRECATED_ADDR2NAME | CAPNET_DEPRECATED_NAME2ADDR | \
    CAPNET_CONNECT | CAPNET_BIND | CAPNET_CONNECTDNS)

/*
 * Defines for the names of the limits.
 * XXX: we should convert all string constats to this to avoid typos.
 */
#define LIMIT_NV_BIND                   "bind"
#define LIMIT_NV_CONNECT                "connect"
#define LIMIT_NV_ADDR2NAME              "addr2name"
#define LIMIT_NV_NAME2ADDR              "name2addr"

struct cap_net_limit {
        cap_channel_t   *cnl_chan;
        uint64_t         cnl_mode;
        nvlist_t        *cnl_addr2name;
        nvlist_t        *cnl_name2addr;
        nvlist_t        *cnl_connect;
        nvlist_t        *cnl_bind;
};

static struct hostent hent;

static void
hostent_free(struct hostent *hp)
{
        unsigned int ii;

        free(hp->h_name);
        hp->h_name = NULL;
        if (hp->h_aliases != NULL) {
                for (ii = 0; hp->h_aliases[ii] != NULL; ii++)
                        free(hp->h_aliases[ii]);
                free(hp->h_aliases);
                hp->h_aliases = NULL;
        }
        if (hp->h_addr_list != NULL) {
                for (ii = 0; hp->h_addr_list[ii] != NULL; ii++)
                        free(hp->h_addr_list[ii]);
                free(hp->h_addr_list);
                hp->h_addr_list = NULL;
        }
}

static struct hostent *
hostent_unpack(const nvlist_t *nvl, struct hostent *hp)
{
        unsigned int ii, nitems;
        char nvlname[64];
        int n;

        hostent_free(hp);

        hp->h_name = strdup(nvlist_get_string(nvl, "name"));
        if (hp->h_name == NULL)
                goto fail;
        hp->h_addrtype = (int)nvlist_get_number(nvl, "addrtype");
        hp->h_length = (int)nvlist_get_number(nvl, "length");

        nitems = (unsigned int)nvlist_get_number(nvl, "naliases");
        hp->h_aliases = calloc(nitems + 1, sizeof(hp->h_aliases[0]));
        if (hp->h_aliases == NULL)
                goto fail;
        for (ii = 0; ii < nitems; ii++) {
                n = snprintf(nvlname, sizeof(nvlname), "alias%u", ii);
                assert(n > 0 && n < (int)sizeof(nvlname));
                hp->h_aliases[ii] =
                    strdup(nvlist_get_string(nvl, nvlname));
                if (hp->h_aliases[ii] == NULL)
                        goto fail;
        }
        hp->h_aliases[ii] = NULL;

        nitems = (unsigned int)nvlist_get_number(nvl, "naddrs");
        hp->h_addr_list = calloc(nitems + 1, sizeof(hp->h_addr_list[0]));
        if (hp->h_addr_list == NULL)
                goto fail;
        for (ii = 0; ii < nitems; ii++) {
                hp->h_addr_list[ii] = malloc(hp->h_length);
                if (hp->h_addr_list[ii] == NULL)
                        goto fail;
                n = snprintf(nvlname, sizeof(nvlname), "addr%u", ii);
                assert(n > 0 && n < (int)sizeof(nvlname));
                bcopy(nvlist_get_binary(nvl, nvlname, NULL),
                    hp->h_addr_list[ii], hp->h_length);
        }
        hp->h_addr_list[ii] = NULL;

        return (hp);
fail:
        hostent_free(hp);
        h_errno = NO_RECOVERY;
        return (NULL);
}

static int
request_cb(cap_channel_t *chan, const char *name, int s,
    const struct sockaddr *saddr, socklen_t len)
{
        nvlist_t *nvl;
        int serrno;

        nvl = nvlist_create(0);
        nvlist_add_string(nvl, "cmd", name);
        nvlist_add_descriptor(nvl, "s", s);
        nvlist_add_binary(nvl, "saddr", saddr, len);

        nvl = cap_xfer_nvlist(chan, nvl);
        if (nvl == NULL)
                return (-1);

        if (nvlist_get_number(nvl, "error") != 0) {
                serrno = (int)nvlist_get_number(nvl, "error");
                nvlist_destroy(nvl);
                errno = serrno;
                return (-1);
        }

        s = dup2(s, nvlist_get_descriptor(nvl, "s"));
        nvlist_destroy(nvl);

        return (s == -1 ? -1 : 0);
}

int
cap_bind(cap_channel_t *chan, int s, const struct sockaddr *addr,
    socklen_t addrlen)
{

        return (request_cb(chan, LIMIT_NV_BIND, s, addr, addrlen));
}

int
cap_connect(cap_channel_t *chan, int s, const struct sockaddr *name,
    socklen_t namelen)
{

        return (request_cb(chan, LIMIT_NV_CONNECT, s, name, namelen));
}


struct hostent *
cap_gethostbyname(cap_channel_t *chan, const char *name)
{

        return (cap_gethostbyname2(chan, name, AF_INET));
}

struct hostent *
cap_gethostbyname2(cap_channel_t *chan, const char *name, int af)
{
        struct hostent *hp;
        nvlist_t *nvl;

        nvl = nvlist_create(0);
        nvlist_add_string(nvl, "cmd", "gethostbyname");
        nvlist_add_number(nvl, "family", (uint64_t)af);
        nvlist_add_string(nvl, "name", name);
        nvl = cap_xfer_nvlist(chan, nvl);
        if (nvl == NULL) {
                h_errno = NO_RECOVERY;
                return (NULL);
        }
        if (nvlist_get_number(nvl, "error") != 0) {
                h_errno = (int)nvlist_get_number(nvl, "error");
                nvlist_destroy(nvl);
                return (NULL);
        }

        hp = hostent_unpack(nvl, &hent);
        nvlist_destroy(nvl);
        return (hp);
}

struct hostent *
cap_gethostbyaddr(cap_channel_t *chan, const void *addr, socklen_t len,
    int af)
{
        struct hostent *hp;
        nvlist_t *nvl;

        nvl = nvlist_create(0);
        nvlist_add_string(nvl, "cmd", "gethostbyaddr");
        nvlist_add_binary(nvl, "addr", addr, (size_t)len);
        nvlist_add_number(nvl, "family", (uint64_t)af);
        nvl = cap_xfer_nvlist(chan, nvl);
        if (nvl == NULL) {
                h_errno = NO_RECOVERY;
                return (NULL);
        }
        if (nvlist_get_number(nvl, "error") != 0) {
                h_errno = (int)nvlist_get_number(nvl, "error");
                nvlist_destroy(nvl);
                return (NULL);
        }
        hp = hostent_unpack(nvl, &hent);
        nvlist_destroy(nvl);
        return (hp);
}

static struct addrinfo *
addrinfo_unpack(const nvlist_t *nvl)
{
        struct addrinfo *ai;
        const void *addr;
        size_t addrlen;
        const char *canonname;

        addr = nvlist_get_binary(nvl, "ai_addr", &addrlen);
        ai = malloc(sizeof(*ai) + addrlen);
        if (ai == NULL)
                return (NULL);
        ai->ai_flags = (int)nvlist_get_number(nvl, "ai_flags");
        ai->ai_family = (int)nvlist_get_number(nvl, "ai_family");
        ai->ai_socktype = (int)nvlist_get_number(nvl, "ai_socktype");
        ai->ai_protocol = (int)nvlist_get_number(nvl, "ai_protocol");
        ai->ai_addrlen = (socklen_t)addrlen;
        canonname = dnvlist_get_string(nvl, "ai_canonname", NULL);
        if (canonname != NULL) {
                ai->ai_canonname = strdup(canonname);
                if (ai->ai_canonname == NULL) {
                        free(ai);
                        return (NULL);
                }
        } else {
                ai->ai_canonname = NULL;
        }
        ai->ai_addr = (void *)(ai + 1);
        bcopy(addr, ai->ai_addr, addrlen);
        ai->ai_next = NULL;

        return (ai);
}

int
cap_getaddrinfo(cap_channel_t *chan, const char *hostname, const char *servname,
    const struct addrinfo *hints, struct addrinfo **res)
{
        struct addrinfo *firstai, *prevai, *curai;
        unsigned int ii;
        const nvlist_t *nvlai;
        char nvlname[64];
        nvlist_t *nvl;
        int error, serrno, n;

        nvl = nvlist_create(0);
        nvlist_add_string(nvl, "cmd", "getaddrinfo");
        if (hostname != NULL)
                nvlist_add_string(nvl, "hostname", hostname);
        if (servname != NULL)
                nvlist_add_string(nvl, "servname", servname);
        if (hints != NULL) {
                nvlist_add_number(nvl, "hints.ai_flags",
                    (uint64_t)hints->ai_flags);
                nvlist_add_number(nvl, "hints.ai_family",
                    (uint64_t)hints->ai_family);
                nvlist_add_number(nvl, "hints.ai_socktype",
                    (uint64_t)hints->ai_socktype);
                nvlist_add_number(nvl, "hints.ai_protocol",
                    (uint64_t)hints->ai_protocol);
        }
        nvl = cap_xfer_nvlist(chan, nvl);
        if (nvl == NULL)
                return (EAI_MEMORY);
        if (nvlist_get_number(nvl, "error") != 0) {
                error = (int)nvlist_get_number(nvl, "error");
                serrno = dnvlist_get_number(nvl, "errno", 0);
                nvlist_destroy(nvl);
                errno = (error == EAI_SYSTEM) ? serrno : 0;
                return (error);
        }

        nvlai = NULL;
        firstai = prevai = curai = NULL;
        for (ii = 0; ; ii++) {
                n = snprintf(nvlname, sizeof(nvlname), "res%u", ii);
                assert(n > 0 && n < (int)sizeof(nvlname));
                if (!nvlist_exists_nvlist(nvl, nvlname))
                        break;
                nvlai = nvlist_get_nvlist(nvl, nvlname);
                curai = addrinfo_unpack(nvlai);
                if (curai == NULL) {
                        nvlist_destroy(nvl);
                        return (EAI_MEMORY);
                }
                if (prevai != NULL)
                        prevai->ai_next = curai;
                else
                        firstai = curai;
                prevai = curai;
        }
        nvlist_destroy(nvl);
        if (curai == NULL && nvlai != NULL) {
                if (firstai == NULL)
                        freeaddrinfo(firstai);
                return (EAI_MEMORY);
        }

        *res = firstai;
        return (0);
}

int
cap_getnameinfo(cap_channel_t *chan, const struct sockaddr *sa, socklen_t salen,
    char *host, size_t hostlen, char *serv, size_t servlen, int flags)
{
        nvlist_t *nvl;
        int error, serrno;

        nvl = nvlist_create(0);
        nvlist_add_string(nvl, "cmd", "getnameinfo");
        nvlist_add_number(nvl, "hostlen", (uint64_t)hostlen);
        nvlist_add_number(nvl, "servlen", (uint64_t)servlen);
        nvlist_add_binary(nvl, "sa", sa, (size_t)salen);
        nvlist_add_number(nvl, "flags", (uint64_t)flags);
        nvl = cap_xfer_nvlist(chan, nvl);
        if (nvl == NULL)
                return (EAI_MEMORY);
        if (nvlist_get_number(nvl, "error") != 0) {
                error = (int)nvlist_get_number(nvl, "error");
                serrno = dnvlist_get_number(nvl, "errno", 0);
                nvlist_destroy(nvl);
                errno = (error == EAI_SYSTEM) ? serrno : 0;
                return (error);
        }

        if (host != NULL && nvlist_exists_string(nvl, "host"))
                strlcpy(host, nvlist_get_string(nvl, "host"), hostlen);
        if (serv != NULL && nvlist_exists_string(nvl, "serv"))
                strlcpy(serv, nvlist_get_string(nvl, "serv"), servlen);
        nvlist_destroy(nvl);
        return (0);
}

cap_net_limit_t *
cap_net_limit_init(cap_channel_t *chan, uint64_t mode)
{
        cap_net_limit_t *limit;

        limit = calloc(1, sizeof(*limit));
        if (limit != NULL) {
                limit->cnl_mode = mode;
                limit->cnl_chan = chan;
                limit->cnl_addr2name = nvlist_create(0);
                limit->cnl_name2addr = nvlist_create(0);
                limit->cnl_connect = nvlist_create(0);
                limit->cnl_bind = nvlist_create(0);
        }

        return (limit);
}

static void
pack_limit(nvlist_t *lnvl, const char *name, nvlist_t *limit)
{

        if (!nvlist_empty(limit)) {
                nvlist_move_nvlist(lnvl, name, limit);
        } else {
                nvlist_destroy(limit);
        }
}

int
cap_net_limit(cap_net_limit_t *limit)
{
        nvlist_t *lnvl;
        cap_channel_t *chan;

        lnvl = nvlist_create(0);
        nvlist_add_number(lnvl, "mode", limit->cnl_mode);

        pack_limit(lnvl, LIMIT_NV_ADDR2NAME, limit->cnl_addr2name);
        pack_limit(lnvl, LIMIT_NV_NAME2ADDR, limit->cnl_name2addr);
        pack_limit(lnvl, LIMIT_NV_CONNECT, limit->cnl_connect);
        pack_limit(lnvl, LIMIT_NV_BIND, limit->cnl_bind);

        chan = limit->cnl_chan;
        free(limit);

        return (cap_limit_set(chan, lnvl));
}

void
cap_net_free(cap_net_limit_t *limit)
{

        if (limit == NULL)
                return;

        nvlist_destroy(limit->cnl_addr2name);
        nvlist_destroy(limit->cnl_name2addr);
        nvlist_destroy(limit->cnl_connect);
        nvlist_destroy(limit->cnl_bind);

        free(limit);
}

static void
pack_family(nvlist_t *nvl, int *family, size_t size)
{
        size_t i;

        i = 0;
        if (!nvlist_exists_number_array(nvl, "family")) {
                uint64_t val;

                val = family[0];
                nvlist_add_number_array(nvl, "family", &val, 1);
                i += 1;
        }

        for (; i < size; i++) {
                nvlist_append_number_array(nvl, "family", family[i]);
        }
}

static void
pack_sockaddr(nvlist_t *res, const struct sockaddr *sa, socklen_t salen)
{
        nvlist_t *nvl;

        if (!nvlist_exists_nvlist(res, "sockaddr")) {
                nvl = nvlist_create(NV_FLAG_NO_UNIQUE);
        } else {
                nvl = nvlist_take_nvlist(res, "sockaddr");
        }

        nvlist_add_binary(nvl, "", sa, salen);
        nvlist_move_nvlist(res, "sockaddr", nvl);
}

cap_net_limit_t *
cap_net_limit_addr2name_family(cap_net_limit_t *limit, int *family, size_t size)
{

        pack_family(limit->cnl_addr2name, family, size);
        return (limit);
}

cap_net_limit_t *
cap_net_limit_name2addr_family(cap_net_limit_t *limit, int *family, size_t size)
{

        pack_family(limit->cnl_name2addr, family, size);
        return (limit);
}

cap_net_limit_t *
cap_net_limit_name2addr(cap_net_limit_t *limit, const char *host,
    const char *serv)
{
        nvlist_t *nvl;

        if (!nvlist_exists_nvlist(limit->cnl_name2addr, "hosts")) {
                nvl = nvlist_create(NV_FLAG_NO_UNIQUE);
        } else {
                nvl = nvlist_take_nvlist(limit->cnl_name2addr, "hosts");
        }

        nvlist_add_string(nvl,
            host != NULL ? host : "",
            serv != NULL ? serv : "");

        nvlist_move_nvlist(limit->cnl_name2addr, "hosts", nvl);
        return (limit);
}

cap_net_limit_t *
cap_net_limit_addr2name(cap_net_limit_t *limit, const struct sockaddr *sa,
    socklen_t salen)
{

        pack_sockaddr(limit->cnl_addr2name, sa, salen);
        return (limit);
}


cap_net_limit_t *
cap_net_limit_connect(cap_net_limit_t *limit, const struct sockaddr *sa,
    socklen_t salen)
{

        pack_sockaddr(limit->cnl_connect, sa, salen);
        return (limit);
}

cap_net_limit_t *
cap_net_limit_bind(cap_net_limit_t *limit, const struct sockaddr *sa,
    socklen_t salen)
{

        pack_sockaddr(limit->cnl_bind, sa, salen);
        return (limit);
}

/*
 * Service functions.
 */

static nvlist_t *capdnscache;

static void
net_add_sockaddr_to_cache(struct sockaddr *sa, socklen_t salen, bool deprecated)
{
        void *cookie;

        if (capdnscache == NULL) {
                capdnscache = nvlist_create(NV_FLAG_NO_UNIQUE);
        } else {
                /* Lets keep it clean. Look for dups. */
                cookie = NULL;
                while (nvlist_next(capdnscache, NULL, &cookie) != NULL) {
                        const void *data;
                        size_t size;

                        assert(cnvlist_type(cookie) == NV_TYPE_BINARY);

                        data = cnvlist_get_binary(cookie, &size);
                        if (salen != size)
                                continue;
                        if (memcmp(data, sa, size) == 0)
                                return;
                }
        }

        nvlist_add_binary(capdnscache, deprecated ? "d" : "", sa, salen);
}

static void
net_add_hostent_to_cache(const char *address, size_t asize, int family)
{

        if (family != AF_INET && family != AF_INET6)
                return;

        if (family == AF_INET6) {
                struct sockaddr_in6 connaddr;

                memset(&connaddr, 0, sizeof(connaddr));
                connaddr.sin6_family = AF_INET6;
                memcpy((char *)&connaddr.sin6_addr, address, asize);
                connaddr.sin6_port = 0;

                net_add_sockaddr_to_cache((struct sockaddr *)&connaddr,
                    sizeof(connaddr), true);
        } else {
                struct sockaddr_in connaddr;

                memset(&connaddr, 0, sizeof(connaddr));
                connaddr.sin_family = AF_INET;
                memcpy((char *)&connaddr.sin_addr.s_addr, address, asize);
                connaddr.sin_port = 0;

                net_add_sockaddr_to_cache((struct sockaddr *)&connaddr,
                    sizeof(connaddr), true);
        }
}

static bool
net_allowed_mode(const nvlist_t *limits, uint64_t mode)
{

        if (limits == NULL)
                return (true);

        return ((nvlist_get_number(limits, "mode") & mode) == mode);
}

static bool
net_allowed_family(const nvlist_t *limits, int family)
{
        const uint64_t *allowedfamily;
        size_t i, allsize;

        if (limits == NULL)
                return (true);

        /* If there are no familes at all, allow any mode. */
        if (!nvlist_exists_number_array(limits, "family"))
                return (true);

        allowedfamily = nvlist_get_number_array(limits, "family", &allsize);
        for (i = 0; i < allsize; i++) {
                /* XXX: what with AF_UNSPEC? */
                if (allowedfamily[i] == (uint64_t)family) {
                        return (true);
                }
        }

        return (false);
}

static bool
net_allowed_bsaddr_impl(const nvlist_t *salimits, const void *saddr,
    size_t saddrsize)
{
        void *cookie;
        const void *limit;
        size_t limitsize;

        cookie = NULL;
        while (nvlist_next(salimits, NULL, &cookie) != NULL) {
                limit = cnvlist_get_binary(cookie, &limitsize);

                if (limitsize != saddrsize) {
                        continue;
                }
                if (memcmp(limit, saddr, limitsize) == 0) {
                        return (true);
                }

                /*
                 * In case of deprecated version (gethostbyname) we have to
                 * ignore port, because there is no such info in the hostent.
                 * Suporting only AF_INET and AF_INET6.
                 */
                if (strcmp(cnvlist_name(cookie), "d") != 0 ||
                    (saddrsize != sizeof(struct sockaddr_in) &&
                    saddrsize != sizeof(struct sockaddr_in6))) {
                        continue;
                }
                if (saddrsize == sizeof(struct sockaddr_in)) {
                        const struct sockaddr_in *saddrptr;
                        struct sockaddr_in sockaddr;

                        saddrptr = (const struct sockaddr_in *)saddr;
                        memcpy(&sockaddr, limit, sizeof(sockaddr));
                        sockaddr.sin_port = saddrptr->sin_port;

                        if (memcmp(&sockaddr, saddr, saddrsize) == 0) {
                                return (true);
                        }
                } else if (saddrsize == sizeof(struct sockaddr_in6)) {
                        const struct sockaddr_in6 *saddrptr;
                        struct sockaddr_in6 sockaddr;

                        saddrptr = (const struct sockaddr_in6 *)saddr;
                        memcpy(&sockaddr, limit, sizeof(sockaddr));
                        sockaddr.sin6_port = saddrptr->sin6_port;

                        if (memcmp(&sockaddr, saddr, saddrsize) == 0) {
                                return (true);
                        }
                }
        }

        return (false);
}

static bool
net_allowed_bsaddr(const nvlist_t *limits, const void *saddr, size_t saddrsize)
{

        if (limits == NULL)
                return (true);

        if (!nvlist_exists_nvlist(limits, "sockaddr"))
                return (true);

        return (net_allowed_bsaddr_impl(nvlist_get_nvlist(limits, "sockaddr"),
            saddr, saddrsize));
}

static bool
net_allowed_hosts(const nvlist_t *limits, const char *name, const char *srvname)
{
        void *cookie;
        const nvlist_t *hlimits;
        const char *testname, *testsrvname;

        if (limits == NULL) {
                return (true);
        }

        /* If there are no hosts at all, allow any. */
        if (!nvlist_exists_nvlist(limits, "hosts")) {
                return (true);
        }

        cookie = NULL;
        testname = (name == NULL ? "" : name);
        testsrvname = (srvname == NULL ? "" : srvname);
        hlimits = nvlist_get_nvlist(limits, "hosts");
        while (nvlist_next(hlimits, NULL, &cookie) != NULL) {
                if (strcmp(cnvlist_name(cookie), "") != 0 &&
                    strcmp(cnvlist_name(cookie), testname) != 0) {
                        continue;
                }

                if (strcmp(cnvlist_get_string(cookie), "") != 0 &&
                    strcmp(cnvlist_get_string(cookie), testsrvname) != 0) {
                        continue;
                }

                return (true);
        }

        return (false);
}

static void
hostent_pack(const struct hostent *hp, nvlist_t *nvl, bool addtocache)
{
        unsigned int ii;
        char nvlname[64];
        int n;

        nvlist_add_string(nvl, "name", hp->h_name);
        nvlist_add_number(nvl, "addrtype", (uint64_t)hp->h_addrtype);
        nvlist_add_number(nvl, "length", (uint64_t)hp->h_length);

        if (hp->h_aliases == NULL) {
                nvlist_add_number(nvl, "naliases", 0);
        } else {
                for (ii = 0; hp->h_aliases[ii] != NULL; ii++) {
                        n = snprintf(nvlname, sizeof(nvlname), "alias%u", ii);
                        assert(n > 0 && n < (int)sizeof(nvlname));
                        nvlist_add_string(nvl, nvlname, hp->h_aliases[ii]);
                }
                nvlist_add_number(nvl, "naliases", (uint64_t)ii);
        }

        if (hp->h_addr_list == NULL) {
                nvlist_add_number(nvl, "naddrs", 0);
        } else {
                for (ii = 0; hp->h_addr_list[ii] != NULL; ii++) {
                        n = snprintf(nvlname, sizeof(nvlname), "addr%u", ii);
                        assert(n > 0 && n < (int)sizeof(nvlname));
                        nvlist_add_binary(nvl, nvlname, hp->h_addr_list[ii],
                            (size_t)hp->h_length);
                        if (addtocache) {
                                net_add_hostent_to_cache(hp->h_addr_list[ii],
                                    hp->h_length, hp->h_addrtype);
                        }
                }
                nvlist_add_number(nvl, "naddrs", (uint64_t)ii);
        }
}

static int
net_gethostbyname(const nvlist_t *limits, const nvlist_t *nvlin,
    nvlist_t *nvlout)
{
        struct hostent *hp;
        int family;
        const nvlist_t *funclimit;
        const char *name;
        bool dnscache;

        if (!net_allowed_mode(limits, CAPNET_DEPRECATED_NAME2ADDR))
                return (ENOTCAPABLE);

        dnscache = net_allowed_mode(limits, CAPNET_CONNECTDNS);
        funclimit = NULL;
        if (limits != NULL) {
                funclimit = dnvlist_get_nvlist(limits, LIMIT_NV_NAME2ADDR,
                    NULL);
        }

        family = (int)nvlist_get_number(nvlin, "family");
        if (!net_allowed_family(funclimit, family))
                return (ENOTCAPABLE);

        name = nvlist_get_string(nvlin, "name");
        if (!net_allowed_hosts(funclimit, name, ""))
                return (ENOTCAPABLE);

        hp = gethostbyname2(name, family);
        if (hp == NULL)
                return (h_errno);
        hostent_pack(hp, nvlout, dnscache);
        return (0);
}

static int
net_gethostbyaddr(const nvlist_t *limits, const nvlist_t *nvlin,
    nvlist_t *nvlout)
{
        struct hostent *hp;
        const void *addr;
        size_t addrsize;
        int family;
        const nvlist_t *funclimit;

        if (!net_allowed_mode(limits, CAPNET_DEPRECATED_ADDR2NAME))
                return (ENOTCAPABLE);

        funclimit = NULL;
        if (limits != NULL) {
                funclimit = dnvlist_get_nvlist(limits, LIMIT_NV_ADDR2NAME,
                    NULL);
        }

        family = (int)nvlist_get_number(nvlin, "family");
        if (!net_allowed_family(funclimit, family))
                return (ENOTCAPABLE);

        addr = nvlist_get_binary(nvlin, "addr", &addrsize);
        if (!net_allowed_bsaddr(funclimit, addr, addrsize))
                return (ENOTCAPABLE);

        hp = gethostbyaddr(addr, (socklen_t)addrsize, family);
        if (hp == NULL)
                return (h_errno);
        hostent_pack(hp, nvlout, false);
        return (0);
}

static int
net_getnameinfo(const nvlist_t *limits, const nvlist_t *nvlin, nvlist_t *nvlout)
{
        struct sockaddr_storage sast;
        const void *sabin;
        char *host, *serv;
        size_t sabinsize, hostlen, servlen;
        socklen_t salen;
        int error, serrno, flags;
        const nvlist_t *funclimit;

        host = serv = NULL;
        if (!net_allowed_mode(limits, CAPNET_ADDR2NAME)) {
                serrno = ENOTCAPABLE;
                error = EAI_SYSTEM;
                goto out;
        }
        funclimit = NULL;
        if (limits != NULL) {
                funclimit = dnvlist_get_nvlist(limits, LIMIT_NV_ADDR2NAME,
                    NULL);
        }
        error = 0;
        memset(&sast, 0, sizeof(sast));

        hostlen = (size_t)nvlist_get_number(nvlin, "hostlen");
        servlen = (size_t)nvlist_get_number(nvlin, "servlen");

        if (hostlen > 0) {
                host = calloc(1, hostlen);
                if (host == NULL) {
                        error = EAI_MEMORY;
                        goto out;
                }
        }
        if (servlen > 0) {
                serv = calloc(1, servlen);
                if (serv == NULL) {
                        error = EAI_MEMORY;
                        goto out;
                }
        }

        sabin = nvlist_get_binary(nvlin, "sa", &sabinsize);
        if (sabinsize > sizeof(sast)) {
                error = EAI_FAIL;
                goto out;
        }
        if (!net_allowed_bsaddr(funclimit, sabin, sabinsize)) {
                serrno = ENOTCAPABLE;
                error = EAI_SYSTEM;
                goto out;
        }

        memcpy(&sast, sabin, sabinsize);
        salen = (socklen_t)sabinsize;

        if ((sast.ss_family != AF_INET ||
             salen != sizeof(struct sockaddr_in)) &&
            (sast.ss_family != AF_INET6 ||
             salen != sizeof(struct sockaddr_in6))) {
                error = EAI_FAIL;
                goto out;
        }

        if (!net_allowed_family(funclimit, (int)sast.ss_family)) {
                serrno = ENOTCAPABLE;
                error = EAI_SYSTEM;
                goto out;
        }

        flags = (int)nvlist_get_number(nvlin, "flags");

        error = getnameinfo((struct sockaddr *)&sast, salen, host, hostlen,
            serv, servlen, flags);
        serrno = errno;
        if (error != 0)
                goto out;

        if (host != NULL)
                nvlist_move_string(nvlout, "host", host);
        if (serv != NULL)
                nvlist_move_string(nvlout, "serv", serv);
out:
        if (error != 0) {
                free(host);
                free(serv);
                if (error == EAI_SYSTEM)
                        nvlist_add_number(nvlout, "errno", serrno);
        }
        return (error);
}

static nvlist_t *
addrinfo_pack(const struct addrinfo *ai)
{
        nvlist_t *nvl;

        nvl = nvlist_create(0);
        nvlist_add_number(nvl, "ai_flags", (uint64_t)ai->ai_flags);
        nvlist_add_number(nvl, "ai_family", (uint64_t)ai->ai_family);
        nvlist_add_number(nvl, "ai_socktype", (uint64_t)ai->ai_socktype);
        nvlist_add_number(nvl, "ai_protocol", (uint64_t)ai->ai_protocol);
        nvlist_add_binary(nvl, "ai_addr", ai->ai_addr, (size_t)ai->ai_addrlen);
        if (ai->ai_canonname != NULL)
                nvlist_add_string(nvl, "ai_canonname", ai->ai_canonname);

        return (nvl);
}

static int
net_getaddrinfo(const nvlist_t *limits, const nvlist_t *nvlin, nvlist_t *nvlout)
{
        struct addrinfo hints, *hintsp, *res, *cur;
        const char *hostname, *servname;
        char nvlname[64];
        nvlist_t *elem;
        unsigned int ii;
        int error, serrno, family, n;
        const nvlist_t *funclimit;
        bool dnscache;

        if (!net_allowed_mode(limits, CAPNET_NAME2ADDR)) {
                serrno = ENOTCAPABLE;
                error = EAI_SYSTEM;
                goto out;
        }
        dnscache = net_allowed_mode(limits, CAPNET_CONNECTDNS);
        funclimit = NULL;
        if (limits != NULL) {
                funclimit = dnvlist_get_nvlist(limits, LIMIT_NV_NAME2ADDR,
                    NULL);
        }

        hostname = dnvlist_get_string(nvlin, "hostname", NULL);
        servname = dnvlist_get_string(nvlin, "servname", NULL);
        if (nvlist_exists_number(nvlin, "hints.ai_flags")) {
                hints.ai_flags = (int)nvlist_get_number(nvlin,
                    "hints.ai_flags");
                hints.ai_family = (int)nvlist_get_number(nvlin,
                    "hints.ai_family");
                hints.ai_socktype = (int)nvlist_get_number(nvlin,
                    "hints.ai_socktype");
                hints.ai_protocol = (int)nvlist_get_number(nvlin,
                    "hints.ai_protocol");
                hints.ai_addrlen = 0;
                hints.ai_addr = NULL;
                hints.ai_canonname = NULL;
                hints.ai_next = NULL;
                hintsp = &hints;
                family = hints.ai_family;
        } else {
                hintsp = NULL;
                family = AF_UNSPEC;
        }

        if (!net_allowed_family(funclimit, family)) {
                errno = ENOTCAPABLE;
                error = EAI_SYSTEM;
                goto out;
        }
        if (!net_allowed_hosts(funclimit, hostname, servname)) {
                errno = ENOTCAPABLE;
                error = EAI_SYSTEM;
                goto out;
        }
        error = getaddrinfo(hostname, servname, hintsp, &res);
        serrno = errno;
        if (error != 0) {
                goto out;
        }

        for (cur = res, ii = 0; cur != NULL; cur = cur->ai_next, ii++) {
                elem = addrinfo_pack(cur);
                n = snprintf(nvlname, sizeof(nvlname), "res%u", ii);
                assert(n > 0 && n < (int)sizeof(nvlname));
                nvlist_move_nvlist(nvlout, nvlname, elem);
                if (dnscache) {
                        net_add_sockaddr_to_cache(cur->ai_addr,
                            cur->ai_addrlen, false);
                }
        }

        freeaddrinfo(res);
        error = 0;
out:
        if (error == EAI_SYSTEM)
                nvlist_add_number(nvlout, "errno", serrno);
        return (error);
}

static int
net_bind(const nvlist_t *limits, nvlist_t *nvlin, nvlist_t *nvlout)
{
        int socket, serrno;
        const void *saddr;
        size_t len;
        const nvlist_t *funclimit;

        if (!net_allowed_mode(limits, CAPNET_BIND))
                return (ENOTCAPABLE);
        funclimit = NULL;
        if (limits != NULL)
                funclimit = dnvlist_get_nvlist(limits, LIMIT_NV_BIND, NULL);

        saddr = nvlist_get_binary(nvlin, "saddr", &len);

        if (!net_allowed_bsaddr(funclimit, saddr, len))
                return (ENOTCAPABLE);

        socket = nvlist_take_descriptor(nvlin, "s");
        if (bind(socket, saddr, len) < 0) {
                serrno = errno;
                close(socket);
                return (serrno);
        }

        nvlist_move_descriptor(nvlout, "s", socket);

        return (0);
}

static int
net_connect(const nvlist_t *limits, nvlist_t *nvlin, nvlist_t *nvlout)
{
        int socket, serrno;
        const void *saddr;
        const nvlist_t *funclimit;
        size_t len;
        bool conn, conndns, allowed;

        conn = net_allowed_mode(limits, CAPNET_CONNECT);
        conndns = net_allowed_mode(limits, CAPNET_CONNECTDNS);

        if (!conn && !conndns)
                return (ENOTCAPABLE);

        funclimit = NULL;
        if (limits != NULL)
                funclimit = dnvlist_get_nvlist(limits, LIMIT_NV_CONNECT, NULL);

        saddr = nvlist_get_binary(nvlin, "saddr", &len);
        allowed = false;

        if (conn && net_allowed_bsaddr(funclimit, saddr, len)) {
                allowed = true;
        }
        if (conndns && capdnscache != NULL &&
           net_allowed_bsaddr_impl(capdnscache, saddr, len)) {
                allowed = true;
        }

        if (allowed == false) {
                return (ENOTCAPABLE);
        }

        socket = dup(nvlist_get_descriptor(nvlin, "s"));
        if (connect(socket, saddr, len) < 0) {
                serrno = errno;
                close(socket);
                return (serrno);
        }

        nvlist_move_descriptor(nvlout, "s", socket);

        return (0);
}

static bool
verify_only_sa_newlimts(const nvlist_t *oldfunclimits,
    const nvlist_t *newfunclimit)
{
        void *cookie;

        cookie = NULL;
        while (nvlist_next(newfunclimit, NULL, &cookie) != NULL) {
                void *sacookie;

                if (strcmp(cnvlist_name(cookie), "sockaddr") != 0)
                        return (false);

                if (cnvlist_type(cookie) != NV_TYPE_NVLIST)
                        return (false);

                sacookie = NULL;
                while (nvlist_next(cnvlist_get_nvlist(cookie), NULL,
                    &sacookie) != NULL) {
                        const void *sa;
                        size_t sasize;

                        if (cnvlist_type(sacookie) != NV_TYPE_BINARY)
                                return (false);

                        sa = cnvlist_get_binary(sacookie, &sasize);
                        if (!net_allowed_bsaddr(oldfunclimits, sa, sasize))
                                return (false);
                }
        }

        return (true);
}

static bool
verify_bind_newlimts(const nvlist_t *oldlimits,
    const nvlist_t *newfunclimit)
{
        const nvlist_t *oldfunclimits;

        oldfunclimits = NULL;
        if (oldlimits != NULL) {
                oldfunclimits = dnvlist_get_nvlist(oldlimits, LIMIT_NV_BIND,
                    NULL);
        }

        return (verify_only_sa_newlimts(oldfunclimits, newfunclimit));
}


static bool
verify_connect_newlimits(const nvlist_t *oldlimits,
    const nvlist_t *newfunclimit)
{
        const nvlist_t *oldfunclimits;

        oldfunclimits = NULL;
        if (oldlimits != NULL) {
                oldfunclimits = dnvlist_get_nvlist(oldlimits, LIMIT_NV_CONNECT,
                    NULL);
        }

        return (verify_only_sa_newlimts(oldfunclimits, newfunclimit));
}

static bool
verify_addr2name_newlimits(const nvlist_t *oldlimits,
    const nvlist_t *newfunclimit)
{
        void *cookie;
        const nvlist_t *oldfunclimits;

        oldfunclimits = NULL;
        if (oldlimits != NULL) {
                oldfunclimits = dnvlist_get_nvlist(oldlimits,
                    LIMIT_NV_ADDR2NAME, NULL);
        }

        cookie = NULL;
        while (nvlist_next(newfunclimit, NULL, &cookie) != NULL) {
                if (strcmp(cnvlist_name(cookie), "sockaddr") == 0) {
                        void *sacookie;

                        if (cnvlist_type(cookie) != NV_TYPE_NVLIST)
                                return (false);

                        sacookie = NULL;
                        while (nvlist_next(cnvlist_get_nvlist(cookie), NULL,
                            &sacookie) != NULL) {
                                const void *sa;
                                size_t sasize;

                                if (cnvlist_type(sacookie) != NV_TYPE_BINARY)
                                        return (false);

                                sa = cnvlist_get_binary(sacookie, &sasize);
                                if (!net_allowed_bsaddr(oldfunclimits, sa,
                                    sasize)) {
                                        return (false);
                                }
                        }
                } else if (strcmp(cnvlist_name(cookie), "family") == 0) {
                        size_t i, sfamilies;
                        const uint64_t *families;

                        if (cnvlist_type(cookie) != NV_TYPE_NUMBER_ARRAY)
                                return (false);

                        families = cnvlist_get_number_array(cookie, &sfamilies);
                        for (i = 0; i < sfamilies; i++) {
                                if (!net_allowed_family(oldfunclimits,
                                    families[i])) {
                                        return (false);
                                }
                        }
                } else {
                        return (false);
                }
        }

        return (true);
}

static bool
verify_name2addr_newlimits(const nvlist_t *oldlimits,
    const nvlist_t *newfunclimit)
{
        void *cookie;
        const nvlist_t *oldfunclimits;

        oldfunclimits = NULL;
        if (oldlimits != NULL) {
                oldfunclimits = dnvlist_get_nvlist(oldlimits,
                    LIMIT_NV_NAME2ADDR, NULL);
        }

        cookie = NULL;
        while (nvlist_next(newfunclimit, NULL, &cookie) != NULL) {
                if (strcmp(cnvlist_name(cookie), "hosts") == 0) {
                        void *hostcookie;

                        if (cnvlist_type(cookie) != NV_TYPE_NVLIST)
                                return (false);

                        hostcookie = NULL;
                        while (nvlist_next(cnvlist_get_nvlist(cookie), NULL,
                            &hostcookie) != NULL) {
                                if (cnvlist_type(hostcookie) != NV_TYPE_STRING)
                                        return (false);

                                if (!net_allowed_hosts(oldfunclimits,
                                    cnvlist_name(hostcookie),
                                    cnvlist_get_string(hostcookie))) {
                                        return (false);
                                }
                        }
                } else if (strcmp(cnvlist_name(cookie), "family") == 0) {
                        size_t i, sfamilies;
                        const uint64_t *families;

                        if (cnvlist_type(cookie) != NV_TYPE_NUMBER_ARRAY)
                                return (false);

                        families = cnvlist_get_number_array(cookie, &sfamilies);
                        for (i = 0; i < sfamilies; i++) {
                                if (!net_allowed_family(oldfunclimits,
                                    families[i])) {
                                        return (false);
                                }
                        }
                } else {
                        return (false);
                }
        }

        return (true);
}

static int
net_limit(const nvlist_t *oldlimits, const nvlist_t *newlimits)
{
        const char *name;
        void *cookie;
        bool hasmode, hasconnect, hasbind, hasaddr2name, hasname2addr;

        /*
         * Modes:
         *      ADDR2NAME:
         *              getnameinfo
         *      DEPRECATED_ADDR2NAME:
         *              gethostbyaddr
         *
         *      NAME2ADDR:
         *              getaddrinfo
         *      DEPRECATED_NAME2ADDR:
         *              gethostbyname
         *
         * Limit scheme:
         *      mode    : NV_TYPE_NUMBER
         *      connect : NV_TYPE_NVLIST
         *              sockaddr : NV_TYPE_NVLIST
         *                      ""      : NV_TYPE_BINARY
         *                      ...     : NV_TYPE_BINARY
         *      bind    : NV_TYPE_NVLIST
         *              sockaddr : NV_TYPE_NVLIST
         *                      ""      : NV_TYPE_BINARY
         *                      ...     : NV_TYPE_BINARY
         *      addr2name : NV_TYPE_NVLIST
         *              family  : NV_TYPE_NUMBER_ARRAY
         *              sockaddr : NV_TYPE_NVLIST
         *                      ""      : NV_TYPE_BINARY
         *                      ...     : NV_TYPE_BINARY
         *      name2addr : NV_TYPE_NVLIST
         *              family : NV_TYPE_NUMBER
         *              hosts   : NV_TYPE_NVLIST
         *                      host    : servname : NV_TYPE_STRING
         */

        hasmode = false;
        hasconnect = false;
        hasbind = false;
        hasaddr2name = false;
        hasname2addr = false;

        cookie = NULL;
        while ((name = nvlist_next(newlimits, NULL, &cookie)) != NULL) {
                if (strcmp(name, "mode") == 0) {
                        if (cnvlist_type(cookie) != NV_TYPE_NUMBER) {
                                return (NO_RECOVERY);
                        }
                        if (!net_allowed_mode(oldlimits,
                            cnvlist_get_number(cookie))) {
                                return (ENOTCAPABLE);
                        }
                        hasmode = true;
                        continue;
                }

                if (cnvlist_type(cookie) != NV_TYPE_NVLIST) {
                        return (NO_RECOVERY);
                }

                if (strcmp(name, LIMIT_NV_BIND) == 0) {
                        hasbind = true;
                        if (!verify_bind_newlimts(oldlimits,
                            cnvlist_get_nvlist(cookie))) {
                                return (ENOTCAPABLE);
                        }
                } else if (strcmp(name, LIMIT_NV_CONNECT) == 0) {
                        hasconnect = true;
                        if (!verify_connect_newlimits(oldlimits,
                            cnvlist_get_nvlist(cookie))) {
                                return (ENOTCAPABLE);
                        }
                } else if (strcmp(name, LIMIT_NV_ADDR2NAME) == 0) {
                        hasaddr2name = true;
                        if (!verify_addr2name_newlimits(oldlimits,
                            cnvlist_get_nvlist(cookie))) {
                                return (ENOTCAPABLE);
                        }
                } else if (strcmp(name, LIMIT_NV_NAME2ADDR) == 0) {
                        hasname2addr = true;
                        if (!verify_name2addr_newlimits(oldlimits,
                            cnvlist_get_nvlist(cookie))) {
                                return (ENOTCAPABLE);
                        }
                }
        }

        /* Mode is required. */
        if (!hasmode)
                return (ENOTCAPABLE);

        /*
         * If the new limit doesn't mention mode or family we have to
         * check if the current limit does have those. Missing mode or
         * family in the limit means that all modes or families are
         * allowed.
         */
        if (oldlimits == NULL)
                return (0);
        if (!hasbind && nvlist_exists(oldlimits, LIMIT_NV_BIND))
                return (ENOTCAPABLE);
        if (!hasconnect && nvlist_exists(oldlimits, LIMIT_NV_CONNECT))
                return (ENOTCAPABLE);
        if (!hasaddr2name && nvlist_exists(oldlimits, LIMIT_NV_ADDR2NAME))
                return (ENOTCAPABLE);
        if (!hasname2addr && nvlist_exists(oldlimits, LIMIT_NV_NAME2ADDR))
                return (ENOTCAPABLE);
        return (0);
}

static int
net_command(const char *cmd, const nvlist_t *limits, nvlist_t *nvlin,
    nvlist_t *nvlout)
{

        if (strcmp(cmd, "bind") == 0)
                return (net_bind(limits, nvlin, nvlout));
        else if (strcmp(cmd, "connect") == 0)
                return (net_connect(limits, nvlin, nvlout));
        else if (strcmp(cmd, "gethostbyname") == 0)
                return (net_gethostbyname(limits, nvlin, nvlout));
        else if (strcmp(cmd, "gethostbyaddr") == 0)
                return (net_gethostbyaddr(limits, nvlin, nvlout));
        else if (strcmp(cmd, "getnameinfo") == 0)
                return (net_getnameinfo(limits, nvlin, nvlout));
        else if (strcmp(cmd, "getaddrinfo") == 0)
                return (net_getaddrinfo(limits, nvlin, nvlout));

        return (EINVAL);
}

CREATE_SERVICE("system.net", net_limit, net_command, 0);