/*-
 * 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
 *
 * ipv6 support
 */

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

#include "ipfw2.h"

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

#include <net/if.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/icmp6.h>
#include <netinet/ip_fw.h>
#include <arpa/inet.h>

#define CHECK_LENGTH(v, len) do {                       \
        if ((v) < (len))                                \
                errx(EX_DATAERR, "Rule too long");      \
        } while (0)

static struct _s_x icmp6codes[] = {
        { "no-route",           ICMP6_DST_UNREACH_NOROUTE },
        { "admin-prohib",               ICMP6_DST_UNREACH_ADMIN },
        { "address",            ICMP6_DST_UNREACH_ADDR },
        { "port",                       ICMP6_DST_UNREACH_NOPORT },
        { NULL, 0 }
};

uint16_t
get_unreach6_code(const char *str)
{
        int val;
        char *s;

        val = strtoul(str, &s, 0);
        if (s == str || *s != '\0' || val >= 0x100)
                val = match_token(icmp6codes, str);
        if (val < 0)
                errx(EX_DATAERR, "unknown ICMPv6 unreachable code ``%s''", str);
        return (val);
}

void
print_unreach6_code(struct buf_pr *bp, uint16_t code)
{
        char const *s = match_value(icmp6codes, code);

        if (s != NULL)
                bprintf(bp, "unreach6 %s", s);
        else
                bprintf(bp, "unreach6 %u", code);
}

/*
 * Print the ip address contained in a command.
 */
void
print_ip6(struct buf_pr *bp, const ipfw_insn_ip6 *cmd)
{
        char trad[255];
        struct hostent *he = NULL;
        const struct in6_addr *a = &(cmd->addr6);
        int len, mb;

        len = F_LEN((const ipfw_insn *)cmd) - 1;
        if (cmd->o.opcode == O_IP6_SRC_ME || cmd->o.opcode == O_IP6_DST_ME) {
                bprintf(bp, " me6");
                return;
        }
        if (cmd->o.opcode == O_IP6) {
                bprintf(bp, " ip6");
                return;
        }

        /*
         * len == 4 indicates a single IP, whereas lists of 1 or more
         * addr/mask pairs have len = (2n+1). We convert len to n so we
         * use that to count the number of entries.
         */
        bprintf(bp, " ");
        for (len = len / 4; len > 0; len -= 2, a += 2) {
                /* mask length */
                mb = (cmd->o.opcode == O_IP6_SRC ||
                    cmd->o.opcode == O_IP6_DST) ?  128:
                    contigmask((const uint8_t *)&(a[1]), 128);

                if (mb == 128 && g_co.do_resolv)
                        he = gethostbyaddr((const char *)a, sizeof(*a),
                            AF_INET6);

                if (he != NULL)      /* resolved to name */
                        bprintf(bp, "%s", he->h_name);
                else if (mb == 0)          /* any */
                        bprintf(bp, "any");
                else {    /* numeric IP followed by some kind of mask */
                        if (inet_ntop(AF_INET6,  a, trad,
                            sizeof(trad)) == NULL)
                                bprintf(bp, "Error ntop in print_ip6\n");
                        bprintf(bp, "%s",  trad );
                        if (mb < 0) /* mask not contiguous */
                                bprintf(bp, "/%s", inet_ntop(AF_INET6, &a[1],
                                    trad, sizeof(trad)));
                        else if (mb < 128)
                                bprintf(bp, "/%d", mb);
                }
                if (len > 2)
                        bprintf(bp, ",");
        }
}

void
fill_icmp6types(ipfw_insn_icmp6 *cmd, char *av, int cblen)
{
       uint8_t type;

       CHECK_LENGTH(cblen, (int)F_INSN_SIZE(ipfw_insn_icmp6));
       memset(cmd, 0, sizeof(*cmd));
       while (*av) {
               if (*av == ',')
                       av++;
               type = strtoul(av, &av, 0);
               if (*av != ',' && *av != '\0')
                       errx(EX_DATAERR, "invalid ICMP6 type");
               /*
                * XXX: shouldn't this be 0xFF?  I can't see any reason why
                * we shouldn't be able to filter all possiable values
                * regardless of the ability of the rest of the kernel to do
                * anything useful with them.
                */
               if (type > ICMP6_MAXTYPE)
                       errx(EX_DATAERR, "ICMP6 type out of range");
               cmd->d[type / 32] |= ( 1 << (type % 32));
       }
       cmd->o.opcode = O_ICMP6TYPE;
       cmd->o.len |= F_INSN_SIZE(ipfw_insn_icmp6);
}

void
print_icmp6types(struct buf_pr *bp, const ipfw_insn_u32 *cmd)
{
        int i, j;
        char sep= ' ';

        bprintf(bp, " icmp6types");
        for (i = 0; i < 7; i++)
                for (j=0; j < 32; ++j) {
                        if ( (cmd->d[i] & (1 << (j))) == 0)
                                continue;
                        bprintf(bp, "%c%d", sep, (i*32 + j));
                        sep = ',';
                }
}

void
print_flow6id(struct buf_pr *bp, const ipfw_insn_u32 *cmd)
{
        uint16_t i, limit = cmd->o.arg1;
        char sep = ',';

        bprintf(bp, " flow-id ");
        for( i=0; i < limit; ++i) {
                if (i == limit - 1)
                        sep = ' ';
                bprintf(bp, "%d%c", cmd->d[i], sep);
        }
}

/* structure and define for the extension header in ipv6 */
static struct _s_x ext6hdrcodes[] = {
        { "frag",       EXT_FRAGMENT },
        { "hopopt",     EXT_HOPOPTS },
        { "route",      EXT_ROUTING },
        { "dstopt",     EXT_DSTOPTS },
        { "ah",  EXT_AH },
        { "esp",        EXT_ESP },
        { "rthdr0",     EXT_RTHDR0 },
        { "rthdr2",     EXT_RTHDR2 },
        { NULL,  0 }
};

/* fills command for the extension header filtering */
int
fill_ext6hdr( ipfw_insn *cmd, char *av)
{
        int tok;
        char *s = av;

        cmd->arg1 = 0;
        while(s) {
                av = strsep( &s, ",") ;
                tok = match_token(ext6hdrcodes, av);
                switch (tok) {
                case EXT_FRAGMENT:
                        cmd->arg1 |= EXT_FRAGMENT;
                        break;
                case EXT_HOPOPTS:
                        cmd->arg1 |= EXT_HOPOPTS;
                        break;
                case EXT_ROUTING:
                        cmd->arg1 |= EXT_ROUTING;
                        break;
                case EXT_DSTOPTS:
                        cmd->arg1 |= EXT_DSTOPTS;
                        break;
                case EXT_AH:
                        cmd->arg1 |= EXT_AH;
                        break;
                case EXT_ESP:
                        cmd->arg1 |= EXT_ESP;
                        break;
                case EXT_RTHDR0:
                        cmd->arg1 |= EXT_RTHDR0;
                        break;
                case EXT_RTHDR2:
                        cmd->arg1 |= EXT_RTHDR2;
                        break;
                default:
                        errx(EX_DATAERR,
                            "invalid option for ipv6 exten header");
                        break;
                }
        }
        if (cmd->arg1 == 0)
                return (0);
        cmd->opcode = O_EXT_HDR;
        cmd->len |= F_INSN_SIZE(ipfw_insn);
        return (1);
}

void
print_ext6hdr(struct buf_pr *bp, const ipfw_insn *cmd )
{
        char sep = ' ';

        bprintf(bp, " extension header:");
        if (cmd->arg1 & EXT_FRAGMENT) {
                bprintf(bp, "%cfragmentation", sep);
                sep = ',';
        }
        if (cmd->arg1 & EXT_HOPOPTS) {
                bprintf(bp, "%chop options", sep);
                sep = ',';
        }
        if (cmd->arg1 & EXT_ROUTING) {
                bprintf(bp, "%crouting options", sep);
                sep = ',';
        }
        if (cmd->arg1 & EXT_RTHDR0) {
                bprintf(bp, "%crthdr0", sep);
                sep = ',';
        }
        if (cmd->arg1 & EXT_RTHDR2) {
                bprintf(bp, "%crthdr2", sep);
                sep = ',';
        }
        if (cmd->arg1 & EXT_DSTOPTS) {
                bprintf(bp, "%cdestination options", sep);
                sep = ',';
        }
        if (cmd->arg1 & EXT_AH) {
                bprintf(bp, "%cauthentication header", sep);
                sep = ',';
        }
        if (cmd->arg1 & EXT_ESP) {
                bprintf(bp, "%cencapsulating security payload", sep);
        }
}

/* Try to find ipv6 address by hostname */
static int
lookup_host6 (char *host, struct in6_addr *ip6addr)
{
        struct hostent *he;

        if (!inet_pton(AF_INET6, host, ip6addr)) {
                if ((he = gethostbyname2(host, AF_INET6)) == NULL)
                        return(-1);
                memcpy(ip6addr, he->h_addr_list[0], sizeof( struct in6_addr));
        }
        return (0);
}


/*
 * fill the addr and mask fields in the instruction as appropriate from av.
 * Update length as appropriate.
 * The following formats are allowed:
 *     any     matches any IP6. Actually returns an empty instruction.
 *     me      returns O_IP6_*_ME
 *
 *     03f1::234:123:0342                       single IP6 address
 *     03f1::234:123:0342/24                    address/masklen
 *     03f1::234:123:0342/ffff::ffff:ffff       address/mask
 *     03f1::234:123:0342/24,03f1::234:123:0343/        List of address
 *
 * Set of address (as in ipv6) not supported because ipv6 address
 * are typically random past the initial prefix.
 * Return 1 on success, 0 on failure.
 */
static int
fill_ip6(ipfw_insn_ip6 *cmd, char *av, int cblen, struct tidx *tstate)
{
        int len = 0;
        struct in6_addr *d = &(cmd->addr6);
        char *oav;
        /*
         * Needed for multiple address.
         * Note d[1] points to struct in6_add r mask6 of cmd
         */

        cmd->o.len &= ~F_LEN_MASK;      /* zero len */

        if (strcmp(av, "any") == 0)
                return (1);

        /* Set the data for "me" opt */
        if (strcmp(av, "me") == 0 || strcmp(av, "me6") == 0) {
                cmd->o.len |= F_INSN_SIZE(ipfw_insn);
                return (1);
        }

        if (strncmp(av, "table(", 6) == 0) {
                fill_table(&cmd->o, av, O_IP_DST_LOOKUP, tstate);
                return (1);
        }

        oav = av = strdup(av);
        while (av) {
                /*
                 * After the address we can have '/' indicating a mask,
                 * or ',' indicating another address follows.
                 */

                char *p, *q;
                int masklen;
                char md = '\0';

                CHECK_LENGTH(cblen,
                    1 + len + 2 * (int)F_INSN_SIZE(struct in6_addr));

                if ((q = strchr(av, ',')) ) {
                        *q = '\0';
                        q++;
                }

                if ((p = strchr(av, '/')) ) {
                        md = *p;        /* save the separator */
                        *p = '\0';      /* terminate address string */
                        p++;            /* and skip past it */
                }
                /* now p points to NULL, mask or next entry */

                /* lookup stores address in *d as a side effect */
                if (lookup_host6(av, d) != 0) {
                        /* XXX: failed. Free memory and go */
                        errx(EX_DATAERR, "bad address \"%s\"", av);
                }
                /* next, look at the mask, if any */
                if (md == '/' && strchr(p, ':')) {
                        if (!inet_pton(AF_INET6, p, &d[1]))
                                errx(EX_DATAERR, "bad mask \"%s\"", p);

                        masklen = contigmask((uint8_t *)&(d[1]), 128);
                } else {
                        masklen = (md == '/') ? atoi(p) : 128;
                        if (masklen > 128 || masklen < 0)
                                errx(EX_DATAERR, "bad width \"%s\''", p);
                        else
                                n2mask(&d[1], masklen);
                }

                APPLY_MASK(d, &d[1]);   /* mask base address with mask */

                av = q;

                /* Check this entry */
                if (masklen == 0) {
                        /*
                         * 'any' turns the entire list into a NOP.
                         * 'not any' never matches, so it is removed from the
                         * list unless it is the only item, in which case we
                         * report an error.
                         */
                        if (cmd->o.len & F_NOT && av == NULL && len == 0)
                                errx(EX_DATAERR, "not any never matches");
                        continue;
                }

                /*
                 * A single IP can be stored alone
                 */
                if (masklen == 128 && av == NULL && len == 0) {
                        len = F_INSN_SIZE(struct in6_addr);
                        break;
                }

                /* Update length and pointer to arguments */
                len += F_INSN_SIZE(struct in6_addr)*2;
                d += 2;
        } /* end while */

        /*
         * Total length of the command, remember that 1 is the size of
         * the base command.
         */
        if (len + 1 > F_LEN_MASK)
                errx(EX_DATAERR, "address list too long");
        cmd->o.len |= len+1;
        free(oav);
        return (1);
}

/*
 * fills command for ipv6 flow-id filtering
 * note that the 20 bit flow number is stored in a array of u_int32_t
 * it's supported lists of flow-id, so in the o.arg1 we store how many
 * additional flow-id we want to filter, the basic is 1
 */
void
fill_flow6( ipfw_insn_u32 *cmd, char *av, int cblen)
{
        u_int32_t type;  /* Current flow number */
        u_int16_t nflow = 0;    /* Current flow index */
        char *s = av;
        cmd->d[0] = 0;    /* Initializing the base number*/

        while (s) {
                CHECK_LENGTH(cblen,
                    (int)F_INSN_SIZE(ipfw_insn_u32) + nflow + 1);

                av = strsep( &s, ",") ;
                type = strtoul(av, &av, 0);
                if (*av != ',' && *av != '\0')
                        errx(EX_DATAERR, "invalid ipv6 flow number %s", av);
                if (type > 0xfffff)
                        errx(EX_DATAERR, "flow number out of range %s", av);
                cmd->d[nflow] |= type;
                nflow++;
        }
        if( nflow > 0 ) {
                cmd->o.opcode = O_FLOW6ID;
                cmd->o.len |= F_INSN_SIZE(ipfw_insn_u32) + nflow;
                cmd->o.arg1 = nflow;
        }
        else {
                errx(EX_DATAERR, "invalid ipv6 flow number %s", av);
        }
}

ipfw_insn *
add_srcip6(ipfw_insn *cmd, char *av, int cblen, struct tidx *tstate)
{

        fill_ip6((ipfw_insn_ip6 *)cmd, av, cblen, tstate);
        if (cmd->opcode == O_IP_DST_SET)                        /* set */
                cmd->opcode = O_IP_SRC_SET;
        else if (cmd->opcode == O_IP_DST_LOOKUP)                /* table */
                cmd->opcode = O_IP_SRC_LOOKUP;
        else if (F_LEN(cmd) == 0) {                             /* any */
        } else if (F_LEN(cmd) == F_INSN_SIZE(ipfw_insn)) {      /* "me" */
                cmd->opcode = O_IP6_SRC_ME;
        } else if (F_LEN(cmd) ==
            (F_INSN_SIZE(struct in6_addr) + F_INSN_SIZE(ipfw_insn))) {
                /* single IP, no mask*/
                cmd->opcode = O_IP6_SRC;
        } else {                                        /* addr/mask opt */
                cmd->opcode = O_IP6_SRC_MASK;
        }
        return cmd;
}

ipfw_insn *
add_dstip6(ipfw_insn *cmd, char *av, int cblen, struct tidx *tstate)
{

        fill_ip6((ipfw_insn_ip6 *)cmd, av, cblen, tstate);
        if (cmd->opcode == O_IP_DST_SET)                        /* set */
                ;
        else if (cmd->opcode == O_IP_DST_LOOKUP)                /* table */
                ;
        else if (F_LEN(cmd) == 0) {                             /* any */
        } else if (F_LEN(cmd) == F_INSN_SIZE(ipfw_insn)) {      /* "me" */
                cmd->opcode = O_IP6_DST_ME;
        } else if (F_LEN(cmd) ==
            (F_INSN_SIZE(struct in6_addr) + F_INSN_SIZE(ipfw_insn))) {
                /* single IP, no mask*/
                cmd->opcode = O_IP6_DST;
        } else {                                        /* addr/mask opt */
                cmd->opcode = O_IP6_DST_MASK;
        }
        return cmd;
}