/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1983, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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/ioctl.h>
#include <sys/socket.h>
#include <net/if.h>

#include <ctype.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ifaddrs.h>

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <arpa/inet.h>
#include <netdb.h>

#include "ifconfig.h"
#include "ifconfig_netlink.h"

#ifdef WITHOUT_NETLINK
static struct in_aliasreq in_addreq;
static struct ifreq in_ridreq;
#else
struct in_px {
        struct in_addr          addr;
        int                     plen;
        bool                    addrset;
        bool                    maskset;
};
struct in_pdata {
        struct in_px            addr;
        struct in_px            dst_addr;
        struct in_px            brd_addr;
        uint32_t                flags;
        uint32_t                vhid;
};
static struct in_pdata in_add, in_del;
#endif

static char addr_buf[NI_MAXHOST];       /*for getnameinfo()*/
extern char *f_inet, *f_addr;

static void
print_addr(struct sockaddr_in *sin)
{
        int error, n_flags;

        if (f_addr != NULL && strcmp(f_addr, "fqdn") == 0)
                n_flags = 0;
        else if (f_addr != NULL && strcmp(f_addr, "host") == 0)
                n_flags = NI_NOFQDN;
        else
                n_flags = NI_NUMERICHOST;

        error = getnameinfo((struct sockaddr *)sin, sin->sin_len, addr_buf,
                            sizeof(addr_buf), NULL, 0, n_flags);

        if (error)
                inet_ntop(AF_INET, &sin->sin_addr, addr_buf, sizeof(addr_buf));
        
        printf("\tinet %s", addr_buf);
}

#ifdef WITHOUT_NETLINK
static void
in_status(if_ctx *ctx __unused, const struct ifaddrs *ifa)
{
        struct sockaddr_in *sin, null_sin = {};

        sin = satosin(ifa->ifa_addr);
        if (sin == NULL)
                return;

        print_addr(sin);

        if (ifa->ifa_flags & IFF_POINTOPOINT) {
                sin = satosin(ifa->ifa_dstaddr);
                if (sin == NULL)
                        sin = &null_sin;
                printf(" --> %s", inet_ntoa(sin->sin_addr));
        }

        sin = satosin(ifa->ifa_netmask);
        if (sin == NULL)
                sin = &null_sin;
        if (f_inet != NULL && strcmp(f_inet, "cidr") == 0) {
                int cidr = 32;
                unsigned long smask;

                smask = ntohl(sin->sin_addr.s_addr);
                while ((smask & 1) == 0) {
                        smask = smask >> 1;
                        cidr--;
                        if (cidr == 0)
                                break;
                }
                printf("/%d", cidr);
        } else if (f_inet != NULL && strcmp(f_inet, "dotted") == 0)
                printf(" netmask %s", inet_ntoa(sin->sin_addr));
        else
                printf(" netmask 0x%lx", (unsigned long)ntohl(sin->sin_addr.s_addr));

        if (ifa->ifa_flags & IFF_BROADCAST) {
                sin = satosin(ifa->ifa_broadaddr);
                if (sin != NULL && sin->sin_addr.s_addr != 0)
                        printf(" broadcast %s", inet_ntoa(sin->sin_addr));
        }

        print_vhid(ifa);

        putchar('\n');
}

#else
static struct in_addr
get_mask(int plen)
{
        struct in_addr a;

        a.s_addr = htonl(plen ? ~((1 << (32 - plen)) - 1) : 0);

        return (a);
}

static void
in_status_nl(if_ctx *ctx __unused, if_link_t *link, if_addr_t *ifa)
{
        struct sockaddr_in *sin = satosin(ifa->ifa_local);
        int plen = ifa->ifa_prefixlen;

        print_addr(sin);

        if (link->ifi_flags & IFF_POINTOPOINT) {
                struct sockaddr_in *dst = satosin(ifa->ifa_address);

                printf(" --> %s", inet_ntoa(dst->sin_addr));
        }
        if (f_inet != NULL && strcmp(f_inet, "cidr") == 0) {
                printf("/%d", plen);
        } else if (f_inet != NULL && strcmp(f_inet, "dotted") == 0)
                printf(" netmask %s", inet_ntoa(get_mask(plen)));
        else
                printf(" netmask 0x%lx", (unsigned long)ntohl(get_mask(plen).s_addr));

        if ((link->ifi_flags & IFF_BROADCAST) && plen != 0)  {
                struct sockaddr_in *brd = satosin(ifa->ifa_broadcast);
                if (brd != NULL)
                        printf(" broadcast %s", inet_ntoa(brd->sin_addr));
        }

        if (ifa->ifaf_vhid != 0)
                printf(" vhid %d", ifa->ifaf_vhid);

        putchar('\n');
}
#endif


#ifdef WITHOUT_NETLINK
#define SIN(x) ((struct sockaddr_in *) &(x))
static struct sockaddr_in *sintab[] = {
        SIN(in_ridreq.ifr_addr), SIN(in_addreq.ifra_addr),
        SIN(in_addreq.ifra_mask), SIN(in_addreq.ifra_broadaddr)
};

static void
in_copyaddr(if_ctx *ctx __unused, int to, int from)
{
        memcpy(sintab[to], sintab[from], sizeof(struct sockaddr_in));
}

static void
in_getaddr(const char *s, int which)
{
        struct sockaddr_in *sin = sintab[which];
        struct hostent *hp;
        struct netent *np;

        sin->sin_len = sizeof(*sin);
        sin->sin_family = AF_INET;

        if (which == ADDR) {
                char *p = NULL;

                if((p = strrchr(s, '/')) != NULL) {
                        const char *errstr;
                        /* address is `name/masklen' */
                        int masklen = 0;
                        struct sockaddr_in *min = sintab[MASK];
                        *p = '\0';
                        if (!isdigit(*(p + 1)))
                                errstr = "invalid";
                        else
                                masklen = (int)strtonum(p + 1, 0, 32, &errstr);
                        if (errstr != NULL) {
                                *p = '/';
                                errx(1, "%s: bad value (width %s)", s, errstr);
                        }
                        min->sin_family = AF_INET;
                        min->sin_len = sizeof(*min);
                        min->sin_addr.s_addr = htonl(~((1LL << (32 - masklen)) - 1) & 
                                              0xffffffff);
                }
        }

        if (inet_aton(s, &sin->sin_addr))
                return;
        if ((hp = gethostbyname(s)) != NULL)
                bcopy(hp->h_addr, (char *)&sin->sin_addr, 
                    MIN((size_t)hp->h_length, sizeof(sin->sin_addr)));
        else if ((np = getnetbyname(s)) != NULL)
                sin->sin_addr = inet_makeaddr(np->n_net, INADDR_ANY);
        else
                errx(1, "%s: bad value", s);
}

#else

static struct in_px *sintab_nl[] = {
        &in_del.addr,           /* RIDADDR */
        &in_add.addr,           /* ADDR */
        NULL,                   /* MASK */
        &in_add.dst_addr,       /* DSTADDR*/
        &in_add.brd_addr,       /* BRDADDR*/
};

static void
in_copyaddr(if_ctx *ctx __unused, int to, int from)
{
        sintab_nl[to]->addr = sintab_nl[from]->addr;
        sintab_nl[to]->addrset = sintab_nl[from]->addrset;
}

static void
in_getip(const char *addr_str, struct in_addr *ip)
{
        struct hostent *hp;
        struct netent *np;

        if (inet_aton(addr_str, ip))
                return;
        if ((hp = gethostbyname(addr_str)) != NULL)
                bcopy(hp->h_addr, (char *)ip,
                    MIN((size_t)hp->h_length, sizeof(ip)));
        else if ((np = getnetbyname(addr_str)) != NULL)
                *ip = inet_makeaddr(np->n_net, INADDR_ANY);
        else
                errx(1, "%s: bad value", addr_str);
}

static void
in_getaddr(const char *s, int which)
{
        struct in_px *px = sintab_nl[which];

        if (which == MASK) {
                struct in_px *px_addr = sintab_nl[ADDR];
                struct in_addr mask = {};

                in_getip(s, &mask);
                px_addr->plen = __bitcount32(mask.s_addr);
                px_addr->maskset = true;
                return;
        }

        if (which == ADDR) {
                char *p = NULL;

                if((p = strrchr(s, '/')) != NULL) {
                        const char *errstr;
                        /* address is `name/masklen' */
                        int masklen;
                        *p = '\0';
                        if (!isdigit(*(p + 1)))
                                errstr = "invalid";
                        else
                                masklen = (int)strtonum(p + 1, 0, 32, &errstr);
                        if (errstr != NULL) {
                                *p = '/';
                                errx(1, "%s: bad value (width %s)", s, errstr);
                        }
                        px->plen = masklen;
                        px->maskset = true;
                }
        }

        in_getip(s, &px->addr);
        px->addrset = true;
}

/*
 * Deletes the first found IPv4 interface address for the interface.
 *
 * This function provides SIOCDIFADDR semantics missing in Netlink.
 * When no valid IPv4 address is specified (sin_family or sin_len is wrong) to
 * the SIOCDIFADDR call, it deletes the first found IPv4 address on the interface.
 * 'ifconfig IFNAME inet addr/prefix' relies on that behavior, as it
 *  executes empty SIOCDIFADDR before adding a new address.
 */
static int
in_delete_first_nl(if_ctx *ctx)
{
        struct nlmsghdr *hdr;
        struct ifaddrmsg *ifahdr;
        uint32_t nlmsg_seq;
        struct in_addr addr;
        struct snl_writer nw = {};
        struct snl_errmsg_data e = {};
        struct snl_state *ss = ctx->io_ss;
        bool found = false;

        uint32_t ifindex = if_nametoindex_nl(ss, ctx->ifname);
        if (ifindex == 0) {
                /* No interface with the desired name, nothing to delete */
                return (EADDRNOTAVAIL);
        }

        snl_init_writer(ss, &nw);
        hdr = snl_create_msg_request(&nw, NL_RTM_GETADDR);
        hdr->nlmsg_flags |= NLM_F_DUMP;
        ifahdr = snl_reserve_msg_object(&nw, struct ifaddrmsg);
        ifahdr->ifa_family = AF_INET;
        ifahdr->ifa_index = ifindex;

        if (! (hdr = snl_finalize_msg(&nw)) || !snl_send_message(ss, hdr))
                return (EINVAL);

        nlmsg_seq = hdr->nlmsg_seq;
        while ((hdr = snl_read_reply_multi(ss, nlmsg_seq, &e)) != NULL) {
                struct snl_parsed_addr attrs = {};
                if (snl_parse_nlmsg(ss, hdr, &snl_rtm_addr_parser, &attrs)) {
                        addr = satosin(attrs.ifa_local)->sin_addr;
                        ifindex = attrs.ifa_index;
                        found = true;
                        break;
                } else
                        return (EINVAL);
        }
        if (e.error != 0) {
                if (e.error_str != NULL)
                        warnx("%s(): %s", __func__, e.error_str);
                return (e.error);
        }

        if (!found)
                return (0);

        /* Try to delete the found address */
        snl_init_writer(ss, &nw);
        hdr = snl_create_msg_request(&nw, NL_RTM_DELADDR);
        ifahdr = snl_reserve_msg_object(&nw, struct ifaddrmsg);
        ifahdr->ifa_family = AF_INET;
        ifahdr->ifa_index = ifindex;
        snl_add_msg_attr_ip4(&nw, IFA_LOCAL, &addr);

        if (! (hdr = snl_finalize_msg(&nw)) || !snl_send_message(ss, hdr))
                return (EINVAL);
        memset(&e, 0, sizeof(e));
        snl_read_reply_code(ss, hdr->nlmsg_seq, &e);
        if (e.error_str != NULL)
                warnx("%s(): %s", __func__, e.error_str);

        return (e.error);
}


static int
in_exec_nl(if_ctx *ctx, unsigned long action, void *data)
{
        struct in_pdata *pdata = (struct in_pdata *)data;
        struct snl_writer nw = {};

        if (action == NL_RTM_DELADDR && !pdata->addr.addrset)
                return (in_delete_first_nl(ctx));

        snl_init_writer(ctx->io_ss, &nw);
        struct nlmsghdr *hdr = snl_create_msg_request(&nw, action);
        struct ifaddrmsg *ifahdr = snl_reserve_msg_object(&nw, struct ifaddrmsg);

        ifahdr->ifa_family = AF_INET;
        ifahdr->ifa_prefixlen = pdata->addr.plen;
        ifahdr->ifa_index = if_nametoindex_nl(ctx->io_ss, ctx->ifname);

        snl_add_msg_attr_ip4(&nw, IFA_LOCAL, &pdata->addr.addr);
        if (action == NL_RTM_NEWADDR && pdata->dst_addr.addrset)
                snl_add_msg_attr_ip4(&nw, IFA_ADDRESS, &pdata->dst_addr.addr);
        if (action == NL_RTM_NEWADDR && pdata->brd_addr.addrset)
                snl_add_msg_attr_ip4(&nw, IFA_BROADCAST, &pdata->brd_addr.addr);

        int off = snl_add_msg_attr_nested(&nw, IFA_FREEBSD);
        snl_add_msg_attr_u32(&nw, IFAF_FLAGS, pdata->flags);
        if (pdata->vhid != 0)
                snl_add_msg_attr_u32(&nw, IFAF_VHID, pdata->vhid);
        snl_end_attr_nested(&nw, off);

        if (! (hdr = snl_finalize_msg(&nw)) || !snl_send_message(ctx->io_ss, hdr))
                return (0);

        struct snl_errmsg_data e = {};
        snl_read_reply_code(ctx->io_ss, hdr->nlmsg_seq, &e);
        if (e.error_str != NULL)
                warnx("%s(): %s", __func__, e.error_str);

        return (e.error);
}
#endif

static void
err_nomask(int ifflags)
{
    if ((ifflags & (IFF_POINTOPOINT | IFF_LOOPBACK)) == 0) {
        errx(1, "ERROR: setting interface address without mask is no longer supported.");
    }
}

static void
in_postproc(if_ctx *ctx __unused, int newaddr, int ifflags)
{
#ifdef WITHOUT_NETLINK
        if (sintab[ADDR]->sin_len != 0 && sintab[MASK]->sin_len == 0 && newaddr) {
                err_nomask(ifflags);
        }
#else
        if (sintab_nl[ADDR]->addrset && !sintab_nl[ADDR]->maskset && newaddr) {
                err_nomask(ifflags);
        }
#endif
}

static void
in_status_tunnel(if_ctx *ctx)
{
        char src[NI_MAXHOST];
        char dst[NI_MAXHOST];
        struct ifreq ifr;
        const struct sockaddr *sa = (const struct sockaddr *) &ifr.ifr_addr;

        memset(&ifr, 0, sizeof(ifr));
        strlcpy(ifr.ifr_name, ctx->ifname, IFNAMSIZ);

        if (ioctl_ctx(ctx, SIOCGIFPSRCADDR, (caddr_t)&ifr) < 0)
                return;
        if (sa->sa_family != AF_INET)
                return;
        if (getnameinfo(sa, sa->sa_len, src, sizeof(src), 0, 0, NI_NUMERICHOST) != 0)
                src[0] = '\0';

        if (ioctl_ctx(ctx, SIOCGIFPDSTADDR, (caddr_t)&ifr) < 0)
                return;
        if (sa->sa_family != AF_INET)
                return;
        if (getnameinfo(sa, sa->sa_len, dst, sizeof(dst), 0, 0, NI_NUMERICHOST) != 0)
                dst[0] = '\0';

        printf("\ttunnel inet %s --> %s\n", src, dst);
}

static void
in_set_tunnel(if_ctx *ctx, struct addrinfo *srcres, struct addrinfo *dstres)
{
        struct in_aliasreq addreq;

        memset(&addreq, 0, sizeof(addreq));
        strlcpy(addreq.ifra_name, ctx->ifname, IFNAMSIZ);
        memcpy(&addreq.ifra_addr, srcres->ai_addr, srcres->ai_addr->sa_len);
        memcpy(&addreq.ifra_dstaddr, dstres->ai_addr, dstres->ai_addr->sa_len);

        if (ioctl_ctx(ctx, SIOCSIFPHYADDR, &addreq) < 0)
                warn("SIOCSIFPHYADDR");
}

static void
in_set_vhid(int vhid)
{
#ifdef WITHOUT_NETLINK
        in_addreq.ifra_vhid = vhid;
#else
        in_add.vhid = (uint32_t)vhid;
#endif
}

static struct afswtch af_inet = {
        .af_name        = "inet",
        .af_af          = AF_INET,
#ifdef WITHOUT_NETLINK
        .af_status      = in_status,
#else
        .af_status      = in_status_nl,
#endif
        .af_getaddr     = in_getaddr,
        .af_copyaddr    = in_copyaddr,
        .af_postproc    = in_postproc,
        .af_status_tunnel = in_status_tunnel,
        .af_settunnel   = in_set_tunnel,
        .af_setvhid     = in_set_vhid,
#ifdef WITHOUT_NETLINK
        .af_difaddr     = SIOCDIFADDR,
        .af_aifaddr     = SIOCAIFADDR,
        .af_ridreq      = &in_ridreq,
        .af_addreq      = &in_addreq,
        .af_exec        = af_exec_ioctl,
#else
        .af_difaddr     = NL_RTM_DELADDR,
        .af_aifaddr     = NL_RTM_NEWADDR,
        .af_ridreq      = &in_del,
        .af_addreq      = &in_add,
        .af_exec        = in_exec_nl,
#endif
};

static __constructor void
inet_ctor(void)
{

#ifndef RESCUE
        if (!feature_present("inet"))
                return;
#endif
        af_register(&af_inet);
}