/*-
 * Copyright (c) 2002-2003 Luigi Rizzo
 * Copyright (c) 1996 Alex Nash, Paul Traina, Poul-Henning Kamp
 * Copyright (c) 1994 Ugen J.S.Antsilevich
 *
 * Idea and grammar partially left from:
 * Copyright (c) 1993 Daniel Boulet
 *
 * Redistribution and use in source forms, with and without modification,
 * are permitted provided that this entire comment appears intact.
 *
 * Redistribution in binary form may occur without any restrictions.
 * Obviously, it would be nice if you gave credit where credit is due
 * but requiring it would be too onerous.
 *
 * This software is provided ``AS IS'' without any warranties of any kind.
 *
 * NEW command line interface for IP firewall facility
 *
 * In-kernel nat support
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sysctl.h>

#include "ipfw2.h"

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h> /* def. of struct route */
#include <netinet/in.h>
#include <netinet/ip_fw.h>
#include <arpa/inet.h>
#include <alias.h>

typedef int (nat_cb_t)(struct nat44_cfg_nat *cfg, void *arg);
static void nat_show_cfg(struct nat44_cfg_nat *n, void *arg);
static void nat_show_log(struct nat44_cfg_nat *n, void *arg);
static int nat_show_data(struct nat44_cfg_nat *cfg, void *arg);
static int natname_cmp(const void *a, const void *b);
static int nat_foreach(nat_cb_t *f, void *arg, int sort);
static int nat_get_cmd(char *name, uint16_t cmd, ipfw_obj_header **ooh);

static struct _s_x nat_params[] = {
        { "ip",                 TOK_IP },
        { "if",                 TOK_IF },
        { "log",                TOK_ALOG },
        { "deny_in",            TOK_DENY_INC },
        { "same_ports",         TOK_SAME_PORTS },
        { "unreg_only",         TOK_UNREG_ONLY },
        { "unreg_cgn",          TOK_UNREG_CGN },
        { "skip_global",        TOK_SKIP_GLOBAL },
        { "reset",              TOK_RESET_ADDR },
        { "reverse",            TOK_ALIAS_REV },
        { "proxy_only",         TOK_PROXY_ONLY },
        { "port_range",         TOK_PORT_ALIAS },
        { "redirect_addr",      TOK_REDIR_ADDR },
        { "redirect_port",      TOK_REDIR_PORT },
        { "redirect_proto",     TOK_REDIR_PROTO },
        { "udp_eim",            TOK_UDP_EIM },
        { NULL, 0 }     /* terminator */
};


/*
 * Search for interface with name "ifn", and fill n accordingly:
 *
 * n->ip        ip address of interface "ifn"
 * n->if_name   copy of interface name "ifn"
 */
static void
set_addr_dynamic(const char *ifn, struct nat44_cfg_nat *n)
{
        size_t needed;
        int mib[6];
        char *buf, *lim, *next;
        struct if_msghdr *ifm;
        struct ifa_msghdr *ifam;
        struct sockaddr_dl *sdl;
        struct sockaddr_in *sin;
        int ifIndex;

        mib[0] = CTL_NET;
        mib[1] = PF_ROUTE;
        mib[2] = 0;
        mib[3] = AF_INET;
        mib[4] = NET_RT_IFLIST;
        mib[5] = 0;
/*
 * Get interface data.
 */
        if (sysctl(mib, 6, NULL, &needed, NULL, 0) == -1)
                err(1, "iflist-sysctl-estimate");
        buf = safe_calloc(1, needed);
        if (sysctl(mib, 6, buf, &needed, NULL, 0) == -1)
                err(1, "iflist-sysctl-get");
        lim = buf + needed;
/*
 * Loop through interfaces until one with
 * given name is found. This is done to
 * find correct interface index for routing
 * message processing.
 */
        ifIndex = 0;
        next = buf;
        while (next < lim) {
                ifm = (struct if_msghdr *)next;
                next += ifm->ifm_msglen;
                if (ifm->ifm_version != RTM_VERSION) {
                        if (g_co.verbose)
                                warnx("routing message version %d "
                                    "not understood", ifm->ifm_version);
                        continue;
                }
                if (ifm->ifm_type == RTM_IFINFO) {
                        sdl = (struct sockaddr_dl *)(ifm + 1);
                        if (strlen(ifn) == sdl->sdl_nlen &&
                            strncmp(ifn, sdl->sdl_data, sdl->sdl_nlen) == 0) {
                                ifIndex = ifm->ifm_index;
                                break;
                        }
                }
        }
        if (!ifIndex)
                errx(1, "unknown interface name %s", ifn);
/*
 * Get interface address.
 */
        sin = NULL;
        while (next < lim) {
                ifam = (struct ifa_msghdr *)next;
                next += ifam->ifam_msglen;
                if (ifam->ifam_version != RTM_VERSION) {
                        if (g_co.verbose)
                                warnx("routing message version %d "
                                    "not understood", ifam->ifam_version);
                        continue;
                }
                if (ifam->ifam_type != RTM_NEWADDR)
                        break;
                if (ifam->ifam_addrs & RTA_IFA) {
                        int i;
                        char *cp = (char *)(ifam + 1);

                        for (i = 1; i < RTA_IFA; i <<= 1) {
                                if (ifam->ifam_addrs & i)
                                        cp += SA_SIZE((struct sockaddr *)cp);
                        }
                        if (((struct sockaddr *)cp)->sa_family == AF_INET) {
                                sin = (struct sockaddr_in *)cp;
                                break;
                        }
                }
        }
        if (sin == NULL)
                n->ip.s_addr = htonl(INADDR_ANY);
        else
                n->ip = sin->sin_addr;
        strncpy(n->if_name, ifn, IF_NAMESIZE);

        free(buf);
}

/*
 * XXX - The following functions, macros and definitions come from natd.c:
 * it would be better to move them outside natd.c, in a file
 * (redirect_support.[ch]?) shared by ipfw and natd, but for now i can live
 * with it.
 */

/*
 * Definition of a port range, and macros to deal with values.
 * FORMAT:  HI 16-bits == first port in range, 0 == all ports.
 *        LO 16-bits == number of ports in range
 * NOTES:   - Port values are not stored in network byte order.
 */

#define port_range u_long

#define GETLOPORT(x)    ((x) >> 0x10)
#define GETNUMPORTS(x)  ((x) & 0x0000ffff)
#define GETHIPORT(x)    (GETLOPORT((x)) + GETNUMPORTS((x)))

/* Set y to be the low-port value in port_range variable x. */
#define SETLOPORT(x,y)   ((x) = ((x) & 0x0000ffff) | ((y) << 0x10))

/* Set y to be the number of ports in port_range variable x. */
#define SETNUMPORTS(x,y) ((x) = ((x) & 0xffff0000) | (y))

static void
StrToAddr (const char* str, struct in_addr* addr)
{
        struct hostent* hp;

        if (inet_aton (str, addr))
                return;

        hp = gethostbyname (str);
        if (!hp)
                errx (1, "unknown host %s", str);

        memcpy (addr, hp->h_addr, sizeof (struct in_addr));
}

static int
StrToPortRange (const char* str, const char* proto, port_range *portRange)
{
        char*      sep;
        struct servent* sp;
        char*           end;
        u_short  loPort;
        u_short  hiPort;

        /* First see if this is a service, return corresponding port if so. */
        sp = getservbyname (str,proto);
        if (sp) {
                SETLOPORT(*portRange, ntohs(sp->s_port));
                SETNUMPORTS(*portRange, 1);
                return 0;
        }

        /* Not a service, see if it's a single port or port range. */
        sep = strchr (str, '-');
        if (sep == NULL) {
                SETLOPORT(*portRange, strtol(str, &end, 10));
                if (end != str) {
                        /* Single port. */
                        SETNUMPORTS(*portRange, 1);
                        return 0;
                }

                /* Error in port range field. */
                errx (EX_DATAERR, "%s/%s: unknown service", str, proto);
        }

        /* Port range, get the values and sanity check. */
        sscanf (str, "%hu-%hu", &loPort, &hiPort);
        SETLOPORT(*portRange, loPort);
        SETNUMPORTS(*portRange, 0);     /* Error by default */
        if (loPort <= hiPort)
                SETNUMPORTS(*portRange, hiPort - loPort + 1);

        if (GETNUMPORTS(*portRange) == 0)
                errx (EX_DATAERR, "invalid port range %s", str);

        return 0;
}

static int
StrToProto (const char* str)
{
        if (!strcmp (str, "tcp"))
                return IPPROTO_TCP;

        if (!strcmp (str, "udp"))
                return IPPROTO_UDP;

        if (!strcmp (str, "sctp"))
                return IPPROTO_SCTP;
        errx (EX_DATAERR, "unknown protocol %s. Expected sctp, tcp or udp", str);
}

static int
StrToAddrAndPortRange (const char* str, struct in_addr* addr, char* proto,
                        port_range *portRange)
{
        char*   ptr;

        ptr = strchr (str, ':');
        if (!ptr)
                errx (EX_DATAERR, "%s is missing port number", str);

        *ptr = '\0';
        ++ptr;

        StrToAddr (str, addr);
        return StrToPortRange (ptr, proto, portRange);
}

/* End of stuff taken from natd.c. */

/*
 * The next 3 functions add support for the addr, port and proto redirect and
 * their logic is loosely based on SetupAddressRedirect(), SetupPortRedirect()
 * and SetupProtoRedirect() from natd.c.
 *
 * Every setup_* function fills at least one redirect entry
 * (struct nat44_cfg_redir) and zero or more server pool entry
 * (struct nat44_cfg_spool) in buf.
 *
 * The format of data in buf is:
 *
 *  nat44_cfg_nat nat44_cfg_redir nat44_cfg_spool    ......  nat44_cfg_spool
 *
 *    -------------------------------------        ------------
 *   |           | .....X ..... |          |         |           |  .....
 *    ------------------------------------- ...... ------------
 *                     ^
 *                spool_cnt       n=0       ......   n=(X-1)
 *
 * len points to the amount of available space in buf
 * space counts the memory consumed by every function
 *
 * XXX - Every function get all the argv params so it
 * has to check, in optional parameters, that the next
 * args is a valid option for the redir entry and not
 * another token. Only redir_port and redir_proto are
 * affected by this.
 */

static int
estimate_redir_addr(int *ac, char ***av)
{
        size_t space = sizeof(struct nat44_cfg_redir);
        char *sep = **av;
        u_int c = 0;

        (void)ac;       /* UNUSED */
        while ((sep = strchr(sep, ',')) != NULL) {
                c++;
                sep++;
        }

        if (c > 0)
                c++;

        space += c * sizeof(struct nat44_cfg_spool);

        return (space);
}

static int
setup_redir_addr(char *buf, int *ac, char ***av)
{
        struct nat44_cfg_redir *r;
        char *sep;
        size_t space;

        r = (struct nat44_cfg_redir *)buf;
        r->mode = REDIR_ADDR;
        /* Skip nat44_cfg_redir at beginning of buf. */
        buf = &buf[sizeof(struct nat44_cfg_redir)];
        space = sizeof(struct nat44_cfg_redir);

        /* Extract local address. */
        if (strchr(**av, ',') != NULL) {
                struct nat44_cfg_spool *spool;

                /* Setup LSNAT server pool. */
                r->laddr.s_addr = INADDR_NONE;
                sep = strtok(**av, ",");
                while (sep != NULL) {
                        spool = (struct nat44_cfg_spool *)buf;
                        space += sizeof(struct nat44_cfg_spool);
                        StrToAddr(sep, &spool->addr);
                        spool->port = ~0;
                        r->spool_cnt++;
                        /* Point to the next possible nat44_cfg_spool. */
                        buf = &buf[sizeof(struct nat44_cfg_spool)];
                        sep = strtok(NULL, ",");
                }
        } else
                StrToAddr(**av, &r->laddr);
        (*av)++; (*ac)--;

        /* Extract public address. */
        StrToAddr(**av, &r->paddr);
        (*av)++; (*ac)--;

        return (space);
}

static int
estimate_redir_port(int *ac, char ***av)
{
        size_t space = sizeof(struct nat44_cfg_redir);
        char *sep = **av;
        u_int c = 0;

        (void)ac;       /* UNUSED */
        while ((sep = strchr(sep, ',')) != NULL) {
                c++;
                sep++;
        }

        if (c > 0)
                c++;

        space += c * sizeof(struct nat44_cfg_spool);

        return (space);
}

static int
setup_redir_port(char *buf, int *ac, char ***av)
{
        struct nat44_cfg_redir *r;
        char *sep, *protoName, *lsnat = NULL;
        size_t space;
        u_short numLocalPorts;
        port_range portRange;

        numLocalPorts = 0;

        r = (struct nat44_cfg_redir *)buf;
        r->mode = REDIR_PORT;
        /* Skip nat44_cfg_redir at beginning of buf. */
        buf = &buf[sizeof(struct nat44_cfg_redir)];
        space = sizeof(struct nat44_cfg_redir);

        /*
         * Extract protocol.
         */
        r->proto = StrToProto(**av);
        protoName = **av;
        (*av)++; (*ac)--;

        /*
         * Extract local address.
         */
        if (strchr(**av, ',') != NULL) {
                r->laddr.s_addr = INADDR_NONE;
                r->lport = ~0;
                numLocalPorts = 1;
                lsnat = **av;
        } else {
                /*
                 * The sctp nat does not allow the port numbers to be mapped to
                 * new port numbers. Therefore, no ports are to be specified
                 * in the target port field.
                 */
                if (r->proto == IPPROTO_SCTP) {
                        if (strchr(**av, ':'))
                                errx(EX_DATAERR, "redirect_port:"
                                    "port numbers do not change in sctp, so do "
                                    "not specify them as part of the target");
                        else
                                StrToAddr(**av, &r->laddr);
                } else {
                        if (StrToAddrAndPortRange(**av, &r->laddr, protoName,
                            &portRange) != 0)
                                errx(EX_DATAERR, "redirect_port: "
                                    "invalid local port range");

                        r->lport = GETLOPORT(portRange);
                        numLocalPorts = GETNUMPORTS(portRange);
                }
        }
        (*av)++; (*ac)--;

        /*
         * Extract public port and optionally address.
         */
        if (strchr(**av, ':') != NULL) {
                if (StrToAddrAndPortRange(**av, &r->paddr, protoName,
                    &portRange) != 0)
                        errx(EX_DATAERR, "redirect_port: "
                            "invalid public port range");
        } else {
                r->paddr.s_addr = INADDR_ANY;
                if (StrToPortRange(**av, protoName, &portRange) != 0)
                        errx(EX_DATAERR, "redirect_port: "
                            "invalid public port range");
        }

        r->pport = GETLOPORT(portRange);
        if (r->proto == IPPROTO_SCTP) { /* so the logic below still works */
                numLocalPorts = GETNUMPORTS(portRange);
                r->lport = r->pport;
        }
        r->pport_cnt = GETNUMPORTS(portRange);
        (*av)++; (*ac)--;

        /*
         * Extract remote address and optionally port.
         */
        /*
         * NB: isdigit(**av) => we've to check that next parameter is really an
         * option for this redirect entry, else stop here processing arg[cv].
         */
        if (*ac != 0 && isdigit(***av)) {
                if (strchr(**av, ':') != NULL) {
                        if (StrToAddrAndPortRange(**av, &r->raddr, protoName,
                            &portRange) != 0)
                                errx(EX_DATAERR, "redirect_port: "
                                    "invalid remote port range");
                } else {
                        SETLOPORT(portRange, 0);
                        SETNUMPORTS(portRange, 1);
                        StrToAddr(**av, &r->raddr);
                }
                (*av)++; (*ac)--;
        } else {
                SETLOPORT(portRange, 0);
                SETNUMPORTS(portRange, 1);
                r->raddr.s_addr = INADDR_ANY;
        }
        r->rport = GETLOPORT(portRange);
        r->rport_cnt = GETNUMPORTS(portRange);

        /*
         * Make sure port ranges match up, then add the redirect ports.
         */
        if (numLocalPorts != r->pport_cnt)
                errx(EX_DATAERR, "redirect_port: "
                    "port ranges must be equal in size");

        /* Remote port range is allowed to be '0' which means all ports. */
        if (r->rport_cnt != numLocalPorts &&
            (r->rport_cnt != 1 || r->rport != 0))
                errx(EX_DATAERR, "redirect_port: remote port must"
                    "be 0 or equal to local port range in size");

        /* Setup LSNAT server pool. */
        if (lsnat != NULL) {
                struct nat44_cfg_spool *spool;

                sep = strtok(lsnat, ",");
                while (sep != NULL) {
                        spool = (struct nat44_cfg_spool *)buf;
                        space += sizeof(struct nat44_cfg_spool);
                        /*
                         * The sctp nat does not allow the port numbers to
                         * be mapped to new port numbers. Therefore, no ports
                         * are to be specified in the target port field.
                         */
                        if (r->proto == IPPROTO_SCTP) {
                                if (strchr (sep, ':')) {
                                        errx(EX_DATAERR, "redirect_port:"
                                            "port numbers do not change in "
                                            "sctp, so do not specify them as "
                                            "part of the target");
                                } else {
                                        StrToAddr(sep, &spool->addr);
                                        spool->port = r->pport;
                                }
                        } else {
                                if (StrToAddrAndPortRange(sep, &spool->addr,
                                        protoName, &portRange) != 0)
                                        errx(EX_DATAERR, "redirect_port:"
                                            "invalid local port range");
                                if (GETNUMPORTS(portRange) != 1)
                                        errx(EX_DATAERR, "redirect_port: "
                                            "local port must be single in "
                                            "this context");
                                spool->port = GETLOPORT(portRange);
                        }
                        r->spool_cnt++;
                        /* Point to the next possible nat44_cfg_spool. */
                        buf = &buf[sizeof(struct nat44_cfg_spool)];
                        sep = strtok(NULL, ",");
                }
        }

        return (space);
}

static int
setup_redir_proto(char *buf, int *ac, char ***av)
{
        struct nat44_cfg_redir *r;
        struct protoent *protoent;
        size_t space;

        r = (struct nat44_cfg_redir *)buf;
        r->mode = REDIR_PROTO;
        /* Skip nat44_cfg_redir at beginning of buf. */
        buf = &buf[sizeof(struct nat44_cfg_redir)];
        space = sizeof(struct nat44_cfg_redir);

        /*
         * Extract protocol.
         */
        protoent = getprotobyname(**av);
        if (protoent == NULL)
                errx(EX_DATAERR, "redirect_proto: unknown protocol %s", **av);
        else
                r->proto = protoent->p_proto;

        (*av)++; (*ac)--;

        /*
         * Extract local address.
         */
        StrToAddr(**av, &r->laddr);

        (*av)++; (*ac)--;

        /*
         * Extract optional public address.
         */
        if (*ac == 0) {
                r->paddr.s_addr = INADDR_ANY;
                r->raddr.s_addr = INADDR_ANY;
        } else {
                /* see above in setup_redir_port() */
                if (isdigit(***av)) {
                        StrToAddr(**av, &r->paddr);
                        (*av)++; (*ac)--;

                        /*
                         * Extract optional remote address.
                         */
                        /* see above in setup_redir_port() */
                        if (*ac != 0 && isdigit(***av)) {
                                StrToAddr(**av, &r->raddr);
                                (*av)++; (*ac)--;
                        }
                }
        }

        return (space);
}

static void
nat_show_log(struct nat44_cfg_nat *n, void *arg __unused)
{
        char *buf;

        buf = (char *)(n + 1);
        if (buf[0] != '\0')
                printf("nat %s: %s\n", n->name, buf);
}

static void
nat_show_cfg(struct nat44_cfg_nat *n, void *arg __unused)
{
        struct nat44_cfg_redir *t;
        struct nat44_cfg_spool *s;
        caddr_t buf;
        struct protoent *p;
        uint32_t cnt;
        int i, off;

        buf = (caddr_t)n;
        off = sizeof(*n);
        printf("ipfw nat %s config", n->name);
        if (strlen(n->if_name) != 0)
                printf(" if %s", n->if_name);
        else if (n->ip.s_addr != 0)
                printf(" ip %s", inet_ntoa(n->ip));
        while (n->mode != 0) {
                if (n->mode & PKT_ALIAS_LOG) {
                        printf(" log");
                        n->mode &= ~PKT_ALIAS_LOG;
                } else if (n->mode & PKT_ALIAS_DENY_INCOMING) {
                        printf(" deny_in");
                        n->mode &= ~PKT_ALIAS_DENY_INCOMING;
                } else if (n->mode & PKT_ALIAS_SAME_PORTS) {
                        printf(" same_ports");
                        n->mode &= ~PKT_ALIAS_SAME_PORTS;
                } else if (n->mode & PKT_ALIAS_SKIP_GLOBAL) {
                        printf(" skip_global");
                        n->mode &= ~PKT_ALIAS_SKIP_GLOBAL;
                } else if (n->mode & PKT_ALIAS_UNREGISTERED_ONLY) {
                        printf(" unreg_only");
                        n->mode &= ~PKT_ALIAS_UNREGISTERED_ONLY;
                } else if (n->mode & PKT_ALIAS_UNREGISTERED_CGN) {
                        printf(" unreg_cgn");
                        n->mode &= ~PKT_ALIAS_UNREGISTERED_CGN;
                } else if (n->mode & PKT_ALIAS_RESET_ON_ADDR_CHANGE) {
                        printf(" reset");
                        n->mode &= ~PKT_ALIAS_RESET_ON_ADDR_CHANGE;
                } else if (n->mode & PKT_ALIAS_REVERSE) {
                        printf(" reverse");
                        n->mode &= ~PKT_ALIAS_REVERSE;
                } else if (n->mode & PKT_ALIAS_PROXY_ONLY) {
                        printf(" proxy_only");
                        n->mode &= ~PKT_ALIAS_PROXY_ONLY;
                } else if (n->mode & PKT_ALIAS_UDP_EIM) {
                        printf(" udp_eim");
                        n->mode &= ~PKT_ALIAS_UDP_EIM;
                }
        }
        /* Print all the redirect's data configuration. */
        for (cnt = 0; cnt < n->redir_cnt; cnt++) {
                t = (struct nat44_cfg_redir *)&buf[off];
                off += sizeof(struct nat44_cfg_redir);
                switch (t->mode) {
                case REDIR_ADDR:
                        printf(" redirect_addr");
                        if (t->spool_cnt == 0)
                                printf(" %s", inet_ntoa(t->laddr));
                        else
                                for (i = 0; i < t->spool_cnt; i++) {
                                        s = (struct nat44_cfg_spool *)&buf[off];
                                        if (i)
                                                printf(",");
                                        else
                                                printf(" ");
                                        printf("%s", inet_ntoa(s->addr));
                                        off += sizeof(struct nat44_cfg_spool);
                                }
                        printf(" %s", inet_ntoa(t->paddr));
                        break;
                case REDIR_PORT:
                        p = getprotobynumber(t->proto);
                        printf(" redirect_port %s ", p->p_name);
                        if (!t->spool_cnt) {
                                printf("%s:%u", inet_ntoa(t->laddr), t->lport);
                                if (t->pport_cnt > 1)
                                        printf("-%u", t->lport +
                                            t->pport_cnt - 1);
                        } else
                                for (i=0; i < t->spool_cnt; i++) {
                                        s = (struct nat44_cfg_spool *)&buf[off];
                                        if (i)
                                                printf(",");
                                        printf("%s:%u", inet_ntoa(s->addr),
                                            s->port);
                                        off += sizeof(struct nat44_cfg_spool);
                                }

                        printf(" ");
                        if (t->paddr.s_addr)
                                printf("%s:", inet_ntoa(t->paddr));
                        printf("%u", t->pport);
                        if (!t->spool_cnt && t->pport_cnt > 1)
                                printf("-%u", t->pport + t->pport_cnt - 1);

                        if (t->raddr.s_addr) {
                                printf(" %s", inet_ntoa(t->raddr));
                                if (t->rport) {
                                        printf(":%u", t->rport);
                                        if (!t->spool_cnt && t->rport_cnt > 1)
                                                printf("-%u", t->rport +
                                                    t->rport_cnt - 1);
                                }
                        }
                        break;
                case REDIR_PROTO:
                        p = getprotobynumber(t->proto);
                        printf(" redirect_proto %s %s", p->p_name,
                            inet_ntoa(t->laddr));
                        if (t->paddr.s_addr != 0) {
                                printf(" %s", inet_ntoa(t->paddr));
                                if (t->raddr.s_addr)
                                        printf(" %s", inet_ntoa(t->raddr));
                        }
                        break;
                default:
                        errx(EX_DATAERR, "unknown redir mode");
                        break;
                }
        }
        printf("\n");
}

static int
nat_port_alias_parse(char *str, u_short *lpout, u_short *hpout) {
        long lp, hp;
        char *ptr;
        /* Lower port parsing */
        lp = (long) strtol(str, &ptr, 10);
        if (lp < 1024 || lp > 65535)
                return 0;
        if (!ptr || *ptr != '-')
                return 0;
        /* Upper port parsing */
        hp = (long) strtol(ptr, &ptr, 10);
        if (hp < 1024 || hp > 65535)
                return 0;
        if (ptr)
                return 0;

        *lpout = (u_short) lp;
        *hpout = (u_short) hp;
        return 1;
}

void
ipfw_config_nat(int ac, char **av)
{
        ipfw_obj_header *oh;
        struct nat44_cfg_nat *n;                /* Nat instance configuration. */
        int i, off, tok, ac1;
        u_short lp, hp;
        char *id, *buf, **av1, *end;
        size_t len;

        av++;
        ac--;
        /* Nat id. */
        if (ac == 0)
                errx(EX_DATAERR, "missing nat id");
        id = *av;
        i = (int)strtol(id, &end, 0);
        if (i <= 0 || *end != '\0')
                errx(EX_DATAERR, "illegal nat id: %s", id);
        av++;
        ac--;
        if (ac == 0)
                errx(EX_DATAERR, "missing option");

        len = sizeof(*oh) + sizeof(*n);
        ac1 = ac;
        av1 = av;
        while (ac1 > 0) {
                tok = match_token(nat_params, *av1);
                ac1--;
                av1++;
                switch (tok) {
                case TOK_IP:
                case TOK_IF:
                case TOK_PORT_ALIAS:
                        ac1--;
                        av1++;
                        break;
                case TOK_ALOG:
                case TOK_DENY_INC:
                case TOK_SAME_PORTS:
                case TOK_SKIP_GLOBAL:
                case TOK_UNREG_ONLY:
                case TOK_UNREG_CGN:
                case TOK_RESET_ADDR:
                case TOK_ALIAS_REV:
                case TOK_PROXY_ONLY:
                case TOK_UDP_EIM:
                        break;
                case TOK_REDIR_ADDR:
                        if (ac1 < 2)
                                errx(EX_DATAERR, "redirect_addr: "
                                    "not enough arguments");
                        len += estimate_redir_addr(&ac1, &av1);
                        av1 += 2;
                        ac1 -= 2;
                        break;
                case TOK_REDIR_PORT:
                        if (ac1 < 3)
                                errx(EX_DATAERR, "redirect_port: "
                                    "not enough arguments");
                        av1++;
                        ac1--;
                        len += estimate_redir_port(&ac1, &av1);
                        av1 += 2;
                        ac1 -= 2;
                        /* Skip optional remoteIP/port */
                        if (ac1 != 0 && isdigit(**av1)) {
                                av1++;
                                ac1--;
                        }
                        break;
                case TOK_REDIR_PROTO:
                        if (ac1 < 2)
                                errx(EX_DATAERR, "redirect_proto: "
                                    "not enough arguments");
                        len += sizeof(struct nat44_cfg_redir);
                        av1 += 2;
                        ac1 -= 2;
                        /* Skip optional remoteIP/port */
                        if (ac1 != 0 && isdigit(**av1)) {
                                av1++;
                                ac1--;
                        }
                        if (ac1 != 0 && isdigit(**av1)) {
                                av1++;
                                ac1--;
                        }
                        break;
                default:
                        errx(EX_DATAERR, "unrecognised option ``%s''", av1[-1]);
                }
        }

        if ((buf = malloc(len)) == NULL)
                errx(EX_OSERR, "malloc failed");

        /* Offset in buf: save space for header at the beginning. */
        off = sizeof(*oh) + sizeof(*n);
        memset(buf, 0, len);
        oh = (ipfw_obj_header *)buf;
        n = (struct nat44_cfg_nat *)(oh + 1);
        oh->ntlv.head.length = sizeof(oh->ntlv);
        snprintf(oh->ntlv.name, sizeof(oh->ntlv.name), "%d", i);
        snprintf(n->name, sizeof(n->name), "%d", i);

        while (ac > 0) {
                tok = match_token(nat_params, *av);
                ac--;
                av++;
                switch (tok) {
                case TOK_IP:
                        if (ac == 0)
                                errx(EX_DATAERR, "missing option");
                        if (!inet_aton(av[0], &(n->ip)))
                                errx(EX_DATAERR, "bad ip address ``%s''",
                                    av[0]);
                        ac--;
                        av++;
                        break;
                case TOK_IF:
                        if (ac == 0)
                                errx(EX_DATAERR, "missing option");
                        set_addr_dynamic(av[0], n);
                        ac--;
                        av++;
                        break;
                case TOK_ALOG:
                        n->mode |= PKT_ALIAS_LOG;
                        break;
                case TOK_DENY_INC:
                        n->mode |= PKT_ALIAS_DENY_INCOMING;
                        break;
                case TOK_SAME_PORTS:
                        n->mode |= PKT_ALIAS_SAME_PORTS;
                        break;
                case TOK_UNREG_ONLY:
                        n->mode |= PKT_ALIAS_UNREGISTERED_ONLY;
                        break;
                case TOK_UNREG_CGN:
                        n->mode |= PKT_ALIAS_UNREGISTERED_CGN;
                        break;
                case TOK_SKIP_GLOBAL:
                        n->mode |= PKT_ALIAS_SKIP_GLOBAL;
                        break;
                case TOK_RESET_ADDR:
                        n->mode |= PKT_ALIAS_RESET_ON_ADDR_CHANGE;
                        break;
                case TOK_ALIAS_REV:
                        n->mode |= PKT_ALIAS_REVERSE;
                        break;
                case TOK_PROXY_ONLY:
                        n->mode |= PKT_ALIAS_PROXY_ONLY;
                        break;
                case TOK_UDP_EIM:
                        n->mode |= PKT_ALIAS_UDP_EIM;
                        break;
                        /*
                         * All the setup_redir_* functions work directly in
                         * the final buffer, see above for details.
                         */
                case TOK_REDIR_ADDR:
                case TOK_REDIR_PORT:
                case TOK_REDIR_PROTO:
                        switch (tok) {
                        case TOK_REDIR_ADDR:
                                i = setup_redir_addr(&buf[off], &ac, &av);
                                break;
                        case TOK_REDIR_PORT:
                                i = setup_redir_port(&buf[off], &ac, &av);
                                break;
                        case TOK_REDIR_PROTO:
                                i = setup_redir_proto(&buf[off], &ac, &av);
                                break;
                        }
                        n->redir_cnt++;
                        off += i;
                        break;
                case TOK_PORT_ALIAS:
                        if (ac == 0)
                                errx(EX_DATAERR, "missing option");
                        if (!nat_port_alias_parse(av[0], &lp, &hp))
                                errx(EX_DATAERR,
                                    "You need a range of port(s) from 1024 <= x < 65536");
                        if (lp >= hp)
                                errx(EX_DATAERR,
                                    "Upper port has to be greater than lower port");
                        n->alias_port_lo = lp;
                        n->alias_port_hi = hp;
                        ac--;
                        av++;
                        break;
                }
        }
        if (n->mode & PKT_ALIAS_SAME_PORTS && n->alias_port_lo)
                errx(EX_DATAERR, "same_ports and port_range cannot both be selected");

        i = do_set3(IP_FW_NAT44_XCONFIG, &oh->opheader, len);
        if (i != 0)
                err(1, "setsockopt(%s)", "IP_FW_NAT44_XCONFIG");

        if (!g_co.do_quiet) {
                /* After every modification, we show the resultant rule. */
                int _ac = 3;
                const char *_av[] = {"show", "config", id};
                ipfw_show_nat(_ac, (char **)(void *)_av);
        }
}

static void
nat_fill_ntlv(ipfw_obj_ntlv *ntlv, int i)
{

        ntlv->head.type = IPFW_TLV_EACTION_NAME(1); /* it doesn't matter */
        ntlv->head.length = sizeof(ipfw_obj_ntlv);
        ntlv->idx = 1;
        ntlv->set = 0; /* not yet */
        snprintf(ntlv->name, sizeof(ntlv->name), "%d", i);
}

int
ipfw_delete_nat(int i)
{
        ipfw_obj_header oh;
        int ret;

        memset(&oh, 0, sizeof(oh));
        nat_fill_ntlv(&oh.ntlv, i);
        ret = do_set3(IP_FW_NAT44_DESTROY, &oh.opheader, sizeof(oh));
        if (ret == -1) {
                if (!g_co.do_quiet)
                        warn("nat %u not available", i);
                return (EX_UNAVAILABLE);
        }
        return (EX_OK);
}

struct nat_list_arg {
        uint16_t        cmd;
        int             is_all;
};

static int
nat_show_data(struct nat44_cfg_nat *cfg, void *arg)
{
        struct nat_list_arg *nla;
        ipfw_obj_header *oh;

        nla = (struct nat_list_arg *)arg;

        switch (nla->cmd) {
        case IP_FW_NAT44_XGETCONFIG:
                if (nat_get_cmd(cfg->name, nla->cmd, &oh) != 0) {
                        warnx("Error getting nat instance %s info", cfg->name);
                        break;
                }
                nat_show_cfg((struct nat44_cfg_nat *)(oh + 1), NULL);
                free(oh);
                break;
        case IP_FW_NAT44_XGETLOG:
                if (nat_get_cmd(cfg->name, nla->cmd, &oh) == 0) {
                        nat_show_log((struct nat44_cfg_nat *)(oh + 1), NULL);
                        free(oh);
                        break;
                }
                /* Handle error */
                if (nla->is_all != 0 && errno == ENOENT)
                        break;
                warn("Error getting nat instance %s info", cfg->name);
                break;
        }

        return (0);
}

/*
 * Compare nat names.
 * Honor number comparison.
 */
static int
natname_cmp(const void *a, const void *b)
{
        const struct nat44_cfg_nat *ia, *ib;

        ia = (const struct nat44_cfg_nat *)a;
        ib = (const struct nat44_cfg_nat *)b;

        return (stringnum_cmp(ia->name, ib->name));
}

/*
 * Retrieves nat list from kernel,
 * optionally sorts it and calls requested function for each table.
 * Returns 0 on success.
 */
static int
nat_foreach(nat_cb_t *f, void *arg, int sort)
{
        ipfw_obj_lheader *olh;
        struct nat44_cfg_nat *cfg;
        size_t sz;
        uint32_t i;

        /* Start with reasonable default */
        sz = sizeof(*olh) + 16 * sizeof(struct nat44_cfg_nat);

        for (;;) {
                if ((olh = calloc(1, sz)) == NULL)
                        return (ENOMEM);

                olh->size = sz;
                if (do_get3(IP_FW_NAT44_LIST_NAT, &olh->opheader, &sz) != 0) {
                        sz = olh->size;
                        free(olh);
                        if (errno == ENOMEM)
                                continue;
                        return (errno);
                }

                if (sort != 0)
                        qsort(olh + 1, olh->count, olh->objsize, natname_cmp);

                cfg = (struct nat44_cfg_nat*)(olh + 1);
                for (i = 0; i < olh->count; i++) {
                        (void)f(cfg, arg); /* Ignore errors for now */
                        cfg = (struct nat44_cfg_nat *)((caddr_t)cfg +
                            olh->objsize);
                }

                free(olh);
                break;
        }

        return (0);
}

static int
nat_get_cmd(char *name, uint16_t cmd, ipfw_obj_header **ooh)
{
        ipfw_obj_header *oh;
        struct nat44_cfg_nat *cfg;
        size_t sz;

        /* Start with reasonable default */
        sz = sizeof(*oh) + sizeof(*cfg) + 128;

        for (;;) {
                if ((oh = calloc(1, sz)) == NULL)
                        return (ENOMEM);
                cfg = (struct nat44_cfg_nat *)(oh + 1);
                oh->ntlv.head.length = sizeof(oh->ntlv);
                strlcpy(oh->ntlv.name, name, sizeof(oh->ntlv.name));
                strlcpy(cfg->name, name, sizeof(cfg->name));

                if (do_get3(cmd, &oh->opheader, &sz) != 0) {
                        sz = cfg->size;
                        free(oh);
                        if (errno == ENOMEM)
                                continue;
                        return (errno);
                }

                *ooh = oh;
                break;
        }

        return (0);
}

void
ipfw_show_nat(int ac, char **av)
{
        ipfw_obj_header *oh;
        char *name;
        int cmd;
        struct nat_list_arg nla;

        ac--;
        av++;

        if (g_co.test_only)
                return;

        /* Parse parameters. */
        cmd = 0; /* XXX: Change to IP_FW_NAT44_XGETLOG @ MFC */
        name = NULL;
        for ( ; ac != 0; ac--, av++) {
                if (!strncmp(av[0], "config", strlen(av[0]))) {
                        cmd = IP_FW_NAT44_XGETCONFIG;
                        continue;
                }
                if (strcmp(av[0], "log") == 0) {
                        cmd = IP_FW_NAT44_XGETLOG;
                        continue;
                }
                if (name != NULL)
                        err(EX_USAGE,"only one instance name may be specified");
                name = av[0];
        }

        if (cmd == 0)
                errx(EX_USAGE, "Please specify action. Available: config,log");

        if (name == NULL) {
                memset(&nla, 0, sizeof(nla));
                nla.cmd = cmd;
                nla.is_all = 1;
                nat_foreach(nat_show_data, &nla, 1);
        } else {
                if (nat_get_cmd(name, cmd, &oh) != 0)
                        err(EX_OSERR, "Error getting nat %s instance info", name);
                nat_show_cfg((struct nat44_cfg_nat *)(oh + 1), NULL);
                free(oh);
        }
}