/*
 * Copyright (C) 2012 by Darren Reed.
 *
 * See the IPFILTER.LICENCE file for details on licencing.
 *
 * Simple FTP transparent proxy for in-kernel use.  For use with the NAT
 * code.
 * Id: ip_ftp_pxy.c,v 2.88.2.19 2006/04/01 10:14:53 darrenr Exp $
 */

#define IPF_FTP_PROXY

#define IPF_MINPORTLEN  18
#define IPF_MINEPRTLEN  20
#define IPF_MAXPORTLEN  30
#define IPF_MIN227LEN   39
#define IPF_MAX227LEN   51
#define IPF_MIN229LEN   47
#define IPF_MAX229LEN   51

#define FTPXY_GO        0
#define FTPXY_INIT      1
#define FTPXY_USER_1    2
#define FTPXY_USOK_1    3
#define FTPXY_PASS_1    4
#define FTPXY_PAOK_1    5
#define FTPXY_AUTH_1    6
#define FTPXY_AUOK_1    7
#define FTPXY_ADAT_1    8
#define FTPXY_ADOK_1    9
#define FTPXY_ACCT_1    10
#define FTPXY_ACOK_1    11
#define FTPXY_USER_2    12
#define FTPXY_USOK_2    13
#define FTPXY_PASS_2    14
#define FTPXY_PAOK_2    15

#define FTPXY_JUNK_OK   0
#define FTPXY_JUNK_BAD  1       /* Ignore all commands for this connection */
#define FTPXY_JUNK_EOL  2       /* consume the rest of this line only */
#define FTPXY_JUNK_CONT 3       /* Saerching for next numeric */

/*
 * Values for FTP commands.  Numerics cover 0-999
 */
#define FTPXY_C_PASV    1000
#define FTPXY_C_PORT    1001
#define FTPXY_C_EPSV    1002
#define FTPXY_C_EPRT    1003


typedef struct ipf_ftp_softc_s {
        int     ipf_p_ftp_pasvonly;
        /* Do not require logins before transfers */
        int     ipf_p_ftp_insecure;
        int     ipf_p_ftp_pasvrdr;
        /* PASV must be last command prior to 227 */
        int     ipf_p_ftp_forcepasv;
        int     ipf_p_ftp_debug;
        int     ipf_p_ftp_single_xfer;
        void    *ipf_p_ftp_tune;
} ipf_ftp_softc_t;


void ipf_p_ftp_main_load(void);
void ipf_p_ftp_main_unload(void);
void *ipf_p_ftp_soft_create(ipf_main_softc_t *);
void ipf_p_ftp_soft_destroy(ipf_main_softc_t *, void *);

int ipf_p_ftp_client(ipf_ftp_softc_t *, fr_info_t *, ip_t *, nat_t *,
                          ftpinfo_t *, int);
int ipf_p_ftp_complete(char *, size_t);
int ipf_p_ftp_in(void *, fr_info_t *, ap_session_t *, nat_t *);
int ipf_p_ftp_new(void *, fr_info_t *, ap_session_t *, nat_t *);
void ipf_p_ftp_del(ipf_main_softc_t *, ap_session_t *);
int ipf_p_ftp_out(void *, fr_info_t *, ap_session_t *, nat_t *);
int ipf_p_ftp_pasv(ipf_ftp_softc_t *, fr_info_t *, ip_t *, nat_t *,
                        ftpinfo_t *, int);
int ipf_p_ftp_epsv(ipf_ftp_softc_t *, fr_info_t *, ip_t *, nat_t *,
                        ftpinfo_t *, int);
int ipf_p_ftp_port(ipf_ftp_softc_t *, fr_info_t *, ip_t *, nat_t *,
                        ftpinfo_t *, int);
int ipf_p_ftp_process(ipf_ftp_softc_t *, fr_info_t *, nat_t *,
                           ftpinfo_t *, int);
int ipf_p_ftp_server(ipf_ftp_softc_t *, fr_info_t *, ip_t *, nat_t *,
                          ftpinfo_t *, int);
int ipf_p_ftp_valid(ipf_ftp_softc_t *, ftpinfo_t *, int, char *, size_t);
int ipf_p_ftp_server_valid(ipf_ftp_softc_t *, ftpside_t *, char *,
                                size_t);
int ipf_p_ftp_client_valid(ipf_ftp_softc_t *, ftpside_t *, char *,
                                size_t);
u_short ipf_p_ftp_atoi(char **);
int ipf_p_ftp_pasvreply(ipf_ftp_softc_t *, fr_info_t *, ip_t *, nat_t *,
                             ftpinfo_t *, u_int, char *, char *);
int ipf_p_ftp_eprt(ipf_ftp_softc_t *, fr_info_t *, ip_t *, nat_t *,
                        ftpinfo_t *, int);
int ipf_p_ftp_eprt4(ipf_ftp_softc_t *, fr_info_t *, ip_t *, nat_t *,
                         ftpinfo_t *, int);
int ipf_p_ftp_eprt6(ipf_ftp_softc_t *, fr_info_t *, ip_t *, nat_t *,
                         ftpinfo_t *, int);
int ipf_p_ftp_addport(ipf_ftp_softc_t *, fr_info_t *, ip_t *, nat_t *,
                           ftpinfo_t *, int, int, int);
void ipf_p_ftp_setpending(ipf_main_softc_t *, ftpinfo_t *);

/*
 * Debug levels
 */
#define DEBUG_SECURITY          0x01
#define DEBUG_ERROR             0x02
#define DEBUG_INFO              0x04
#define DEBUG_PARSE_ERR         0x08
#define DEBUG_PARSE_INFO        0x10
#define DEBUG_PARSE             0x20

static  int     ipf_p_ftp_proxy_init = 0;
static  frentry_t       ftppxyfr;
static  ipftuneable_t   ipf_ftp_tuneables[] = {
        { { (void *)offsetof(ipf_ftp_softc_t, ipf_p_ftp_debug) },
                "ftp_debug",    0,      0x7f,
                stsizeof(ipf_ftp_softc_t, ipf_p_ftp_debug),
                0, NULL, NULL },
        { { (void *)offsetof(ipf_ftp_softc_t, ipf_p_ftp_pasvonly) },
                "ftp_pasvonly", 0,      1,
                stsizeof(ipf_ftp_softc_t, ipf_p_ftp_pasvonly),
                0, NULL, NULL },
        { { (void *)offsetof(ipf_ftp_softc_t, ipf_p_ftp_insecure) },
                "ftp_insecure", 0,      1,
                stsizeof(ipf_ftp_softc_t, ipf_p_ftp_insecure),
                0, NULL, NULL },
        { { (void *)offsetof(ipf_ftp_softc_t, ipf_p_ftp_pasvrdr) },
                "ftp_pasvrdr",  0,      1,
                stsizeof(ipf_ftp_softc_t, ipf_p_ftp_pasvrdr),
                0, NULL, NULL },
        { { (void *)offsetof(ipf_ftp_softc_t, ipf_p_ftp_forcepasv) },
                "ftp_forcepasv", 0,     1,
                stsizeof(ipf_ftp_softc_t, ipf_p_ftp_forcepasv),
                0, NULL, NULL },
        { { (void *)offsetof(ipf_ftp_softc_t, ipf_p_ftp_single_xfer) },
                "ftp_single_xfer", 0,   1,
                stsizeof(ipf_ftp_softc_t, ipf_p_ftp_single_xfer),
                0, NULL, NULL },
        { { NULL }, NULL, 0, 0, 0, 0, NULL, NULL }
};


void
ipf_p_ftp_main_load(void)
{
        bzero((char *)&ftppxyfr, sizeof(ftppxyfr));
        ftppxyfr.fr_ref = 1;
        ftppxyfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;

        MUTEX_INIT(&ftppxyfr.fr_lock, "FTP Proxy Mutex");
        ipf_p_ftp_proxy_init = 1;
}


void
ipf_p_ftp_main_unload(void)
{

        if (ipf_p_ftp_proxy_init == 1) {
                MUTEX_DESTROY(&ftppxyfr.fr_lock);
                ipf_p_ftp_proxy_init = 0;
        }
}


/*
 * Initialize local structures.
 */
void *
ipf_p_ftp_soft_create(ipf_main_softc_t *softc)
{
        ipf_ftp_softc_t *softf;

        KMALLOC(softf, ipf_ftp_softc_t *);
        if (softf == NULL)
                return (NULL);

        bzero((char *)softf, sizeof(*softf));
#if defined(_KERNEL)
        softf->ipf_p_ftp_debug = 0;
#else
        softf->ipf_p_ftp_debug = DEBUG_PARSE_ERR;
#endif
        softf->ipf_p_ftp_forcepasv = 1;

        softf->ipf_p_ftp_tune = ipf_tune_array_copy(softf,
                                                    sizeof(ipf_ftp_tuneables),
                                                    ipf_ftp_tuneables);
        if (softf->ipf_p_ftp_tune == NULL) {
                ipf_p_ftp_soft_destroy(softc, softf);
                return (NULL);
        }
        if (ipf_tune_array_link(softc, softf->ipf_p_ftp_tune) == -1) {
                ipf_p_ftp_soft_destroy(softc, softf);
                return (NULL);
        }

        return (softf);
}


void
ipf_p_ftp_soft_destroy(ipf_main_softc_t *softc, void *arg)
{
        ipf_ftp_softc_t *softf = arg;

        if (softf->ipf_p_ftp_tune != NULL) {
                ipf_tune_array_unlink(softc, softf->ipf_p_ftp_tune);
                KFREES(softf->ipf_p_ftp_tune, sizeof(ipf_ftp_tuneables));
                softf->ipf_p_ftp_tune = NULL;
        }

        KFREE(softf);
}


int
ipf_p_ftp_new(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat __unused)
{
        ftpinfo_t *ftp;
        ftpside_t *f;

        KMALLOC(ftp, ftpinfo_t *);
        if (ftp == NULL)
                return (-1);

        aps->aps_data = ftp;
        aps->aps_psiz = sizeof(ftpinfo_t);
        aps->aps_sport = htons(fin->fin_sport);
        aps->aps_dport = htons(fin->fin_dport);

        bzero((char *)ftp, sizeof(*ftp));
        f = &ftp->ftp_side[0];
        f->ftps_rptr = f->ftps_buf;
        f->ftps_wptr = f->ftps_buf;
        f = &ftp->ftp_side[1];
        f->ftps_rptr = f->ftps_buf;
        f->ftps_wptr = f->ftps_buf;
        ftp->ftp_passok = FTPXY_INIT;
        ftp->ftp_incok = 0;
        return (0);
}


void
ipf_p_ftp_setpending(ipf_main_softc_t *softc, ftpinfo_t *ftp)
{
        if (ftp->ftp_pendnat != NULL)
                ipf_nat_setpending(softc, ftp->ftp_pendnat);

        if (ftp->ftp_pendstate != NULL) {
                READ_ENTER(&softc->ipf_state);
                ipf_state_setpending(softc, ftp->ftp_pendstate);
                RWLOCK_EXIT(&softc->ipf_state);
        }
}


void
ipf_p_ftp_del(ipf_main_softc_t *softc, ap_session_t *aps)
{
        ftpinfo_t *ftp;

        ftp = aps->aps_data;
        if (ftp != NULL)
                ipf_p_ftp_setpending(softc, ftp);
}


int
ipf_p_ftp_port(ipf_ftp_softc_t *softf, fr_info_t *fin, ip_t *ip, nat_t *nat,
        ftpinfo_t *ftp, int dlen)
{
        char newbuf[IPF_FTPBUFSZ], *s;
        u_int a1, a2, a3, a4;
        u_short a5, a6, sp;
        size_t nlen, olen;
        tcphdr_t *tcp;
        int inc, off;
        ftpside_t *f;
        mb_t *m;

        m = fin->fin_m;
        f = &ftp->ftp_side[0];
        tcp = (tcphdr_t *)fin->fin_dp;
        off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;

        /*
         * Check for client sending out PORT message.
         */
        if (dlen < IPF_MINPORTLEN) {
                DT3(ftp_PORT_error_dlen, nat_t *, nat, ftpside_t *, f,
                    u_int, dlen);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE)
                        printf("ipf_p_ftp_port:dlen(%d) < IPF_MINPORTLEN\n",
                               dlen);
                return (0);
        }
        /*
         * Skip the PORT command + space
         */
        s = f->ftps_rptr + 5;
        /*
         * Pick out the address components, two at a time.
         */
        a1 = ipf_p_ftp_atoi(&s);
        if (s == NULL) {
                DT2(ftp_PORT_error_atoi_1, nat_t *, nat, ftpside_t *, f);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_port:ipf_p_ftp_atoi(%d) failed\n", 1);
                return (0);
        }
        a2 = ipf_p_ftp_atoi(&s);
        if (s == NULL) {
                DT2(ftp_PORT_error_atoi_2, nat_t *, nat, ftpside_t *, f);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_port:ipf_p_ftp_atoi(%d) failed\n", 2);
                return (0);
        }

        /*
         * Check that IP address in the PORT/PASV reply is the same as the
         * sender of the command - prevents using PORT for port scanning.
         */
        a1 <<= 16;
        a1 |= a2;
        if (((nat->nat_dir == NAT_OUTBOUND) &&
             (a1 != ntohl(nat->nat_osrcaddr))) ||
            ((nat->nat_dir == NAT_INBOUND) &&
             (a1 != ntohl(nat->nat_nsrcaddr)))) {
                DT3(ftp_PORT_error_address, nat_t *, nat, ftpside_t *, f,
                    u_int, a1);
                if (softf->ipf_p_ftp_debug & DEBUG_ERROR)
                        printf("ipf_p_ftp_port:%s != nat->nat_inip\n", "a1");
                return (APR_ERR(1));
        }

        a5 = ipf_p_ftp_atoi(&s);
        if (s == NULL) {
                DT2(ftp_PORT_error_atoi_3, nat_t *, nat, ftpside_t *, f);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_port:ipf_p_ftp_atoi(%d) failed\n", 3);
                return (0);
        }
        if (*s == ')')
                s++;

        /*
         * check for CR-LF at the end.
         */
        if (*s == '\n')
                s--;
        if ((*s != '\r') || (*(s + 1) != '\n')) {
                DT2(ftp_PORT_error_no_crlf, nat_t *, nat, ftpside_t *, f);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_port:missing %s\n", "cr-lf");
                return (0);
        }
        s += 2;
        a6 = a5 & 0xff;

        /*
         * Calculate the source port. Verification of > 1024 is in
         * ipf_p_ftp_addport.
         */
        a5 >>= 8;
        a5 &= 0xff;
        sp = a5 << 8 | a6;

        /*
         * Calculate new address parts for PORT command
         */
        if (nat->nat_dir == NAT_INBOUND)
                a1 = ntohl(nat->nat_ndstaddr);
        else
                a1 = ntohl(ip->ip_src.s_addr);
        a1 = ntohl(ip->ip_src.s_addr);
        a2 = (a1 >> 16) & 0xff;
        a3 = (a1 >> 8) & 0xff;
        a4 = a1 & 0xff;
        a1 >>= 24;
        olen = s - f->ftps_rptr;
        (void) snprintf(newbuf, sizeof(newbuf), "%s %u,%u,%u,%u,%u,%u\r\n",
                       "PORT", a1, a2, a3, a4, a5, a6);

        nlen = strlen(newbuf);
        inc = nlen - olen;
        if ((inc + fin->fin_plen) > 65535) {
                DT3(ftp_PORT_error_inc, nat_t *, nat, ftpside_t *, f,
                    int, inc);
                if (softf->ipf_p_ftp_debug & DEBUG_ERROR)
                        printf("ipf_p_ftp_port:inc(%d) + ip->ip_len > 65535\n",
                               inc);
                return (0);
        }

#if !defined(_KERNEL)
        M_ADJ(m, inc);
#else
        /*
         * m_adj takes care of pkthdr.len, if required and treats inc<0 to
         * mean remove -len bytes from the end of the packet.
         * The mbuf chain will be extended if necessary by m_copyback().
         */
        if (inc < 0)
                M_ADJ(m, inc);
#endif /* !defined(_KERNEL) */
        COPYBACK(m, off, nlen, newbuf);
        fin->fin_flx |= FI_DOCKSUM;

        if (inc != 0) {
                fin->fin_plen += inc;
                ip->ip_len = htons(fin->fin_plen);
                fin->fin_dlen += inc;
        }

        f->ftps_cmd = FTPXY_C_PORT;
        return (ipf_p_ftp_addport(softf, fin, ip, nat, ftp, dlen, sp, inc));
}


int
ipf_p_ftp_addport(ipf_ftp_softc_t *softf, fr_info_t *fin, ip_t *ip, nat_t *nat,
        ftpinfo_t *ftp, int dlen, int nport, int inc)
{
        tcphdr_t tcph, *tcp2 = &tcph;
        ipf_main_softc_t *softc;
        ipf_nat_softc_t *softn;
        int direction;
        fr_info_t fi;
        ipnat_t *ipn;
        nat_t *nat2;
        u_short sp;
        int flags;

        softc = fin->fin_main_soft;
        softn = softc->ipf_nat_soft;

        if ((ftp->ftp_pendnat != NULL)  || (ftp->ftp_pendstate != NULL)) {
                if (softf->ipf_p_ftp_single_xfer != 0) {
                        DT2(ftp_PORT_error_add_active, nat_t *, nat,
                            ftpinfo_t *, ftp);
                        if (softf->ipf_p_ftp_debug & DEBUG_ERROR)
                                printf("ipf_p_ftp_addport:xfer active %p/%p\n",
                                       ftp->ftp_pendnat, ftp->ftp_pendstate);
                        return (0);
                }
                ipf_p_ftp_setpending(softc, ftp);
        }

        /*
         * Add skeleton NAT entry for connection which will come back the
         * other way.
         */
        sp = nport;
        /*
         * Don't allow the PORT command to specify a port < 1024 due to
         * security risks.
         */
        if (sp < 1024) {
                DT3(ftp_PORT_error_port, nat_t *, nat, ftpinfo_t *, ftp,
                    u_int, sp);
                if (softf->ipf_p_ftp_debug & DEBUG_SECURITY)
                        printf("ipf_p_ftp_addport:sp(%d) < 1024\n", sp);
                return (0);
        }
        /*
         * The server may not make the connection back from port 20, but
         * it is the most likely so use it here to check for a conflicting
         * mapping.
         */
        bcopy((char *)fin, (char *)&fi, sizeof(fi));
        fi.fin_flx |= FI_IGNORE;
        fi.fin_data[0] = sp;
        fi.fin_data[1] = fin->fin_data[1] - 1;
        fi.fin_src6 = nat->nat_ndst6;
        fi.fin_dst6 = nat->nat_nsrc6;

#ifndef USE_INET6
        if (nat->nat_v[0] == 6)
                return (APR_INC(inc));
#endif

        /*
         * If an existing entry already exists, use it instead.
         */
#ifdef USE_INET6
        if (nat->nat_v[0] == 6) {
                if (nat->nat_dir == NAT_OUTBOUND) {
                        nat2 = ipf_nat6_outlookup(&fi, IPN_TCP|NAT_SEARCH,
                                                  nat->nat_pr[1],
                                                  &nat->nat_osrc6.in6,
                                                  &nat->nat_odst6.in6);
                } else {
                        nat2 = ipf_nat6_inlookup(&fi, IPN_TCP|NAT_SEARCH,
                                                 nat->nat_pr[0],
                                                 &nat->nat_odst6.in6,
                                                 &nat->nat_osrc6.in6);
                }
        } else
#endif
        {
                if (nat->nat_dir == NAT_OUTBOUND) {
                        nat2 = ipf_nat_outlookup(&fi, IPN_TCP|NAT_SEARCH,
                                                 nat->nat_pr[1],
                                                 nat->nat_osrcip,
                                                 nat->nat_odstip);
                } else {
                        nat2 = ipf_nat_inlookup(&fi, IPN_TCP|NAT_SEARCH,
                                                nat->nat_pr[0],
                                                nat->nat_odstip,
                                                nat->nat_osrcip);
                }
        }
        if (nat2 != NULL)
                return (APR_INC(inc));

        /*
         * An existing entry doesn't exist. Let's make one.
         */
        ipn = ipf_proxy_rule_rev(nat);
        if (ipn == NULL)
                return (APR_ERR(1));
        ipn->in_use = 0;

        fi.fin_fr = &ftppxyfr;
        fi.fin_dp = (char *)tcp2;
        fi.fin_dlen = sizeof(*tcp2);
        fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
        fi.fin_flx &= FI_LOWTTL|FI_FRAG|FI_TCPUDP|FI_OPTIONS|FI_IGNORE;
        fi.fin_data[1] = sp;
        fi.fin_data[0] = 0;

        bzero((char *)tcp2, sizeof(*tcp2));
        tcp2->th_sport = 0;
        tcp2->th_dport = htons(sp);

        tcp2->th_win = htons(8192);
        TCP_OFF_A(tcp2, 5);
        tcp_set_flags(tcp2, TH_SYN);

        if (nat->nat_dir == NAT_INBOUND) {
                fi.fin_out = 1;
                direction = NAT_OUTBOUND;
        } else {
                fi.fin_out = 0;
                direction = NAT_INBOUND;
        }
        flags = SI_W_SPORT|NAT_SLAVE|IPN_TCP;

        MUTEX_ENTER(&softn->ipf_nat_new);
#ifdef USE_INET6
        if (nat->nat_v[0] == 6)
                nat2 = ipf_nat6_add(&fi, ipn, &ftp->ftp_pendnat, flags,
                                    direction);
        else
#endif
                nat2 = ipf_nat_add(&fi, ipn, &ftp->ftp_pendnat, flags,
                                   direction);
        MUTEX_EXIT(&softn->ipf_nat_new);

        if (nat2 == NULL) {
                KFREES(ipn, ipn->in_size);
                return (APR_ERR(1));
        }

        (void) ipf_nat_proto(&fi, nat2, IPN_TCP);
        MUTEX_ENTER(&nat2->nat_lock);
        ipf_nat_update(&fi, nat2);
        MUTEX_EXIT(&nat2->nat_lock);
        fi.fin_ifp = NULL;
        if (nat2->nat_dir == NAT_INBOUND)
                fi.fin_dst6 = nat->nat_osrc6;
        if (ipf_state_add(softc, &fi, (ipstate_t **)&ftp->ftp_pendstate,
                          SI_W_SPORT) != 0)
                ipf_nat_setpending(softc, nat2);

        return (APR_INC(inc));
}


int
ipf_p_ftp_client(ipf_ftp_softc_t *softf, fr_info_t *fin, ip_t *ip,
        nat_t *nat, ftpinfo_t *ftp, int dlen)
{
        char *rptr, *wptr, cmd[6], c;
        ftpside_t *f;
        int inc, i;

        inc = 0;
        f = &ftp->ftp_side[0];
        rptr = f->ftps_rptr;
        wptr = f->ftps_wptr;

        for (i = 0; (i < 5) && (i < dlen); i++) {
                c = rptr[i];
                if (ISALPHA(c)) {
                        cmd[i] = TOUPPER(c);
                } else {
                        cmd[i] = c;
                }
        }
        cmd[i] = '\0';

        ftp->ftp_incok = 0;
        DT2(ftp_client_command, char [], cmd, int, ftp->ftp_passok);
        if (!strncmp(cmd, "USER ", 5) || !strncmp(cmd, "XAUT ", 5)) {
                if (ftp->ftp_passok == FTPXY_ADOK_1 ||
                    ftp->ftp_passok == FTPXY_AUOK_1) {
                        ftp->ftp_passok = FTPXY_USER_2;
                        ftp->ftp_incok = 1;
                } else {
                        ftp->ftp_passok = FTPXY_USER_1;
                        ftp->ftp_incok = 1;
                }
        } else if (!strncmp(cmd, "AUTH ", 5)) {
                ftp->ftp_passok = FTPXY_AUTH_1;
                ftp->ftp_incok = 1;
        } else if (!strncmp(cmd, "PASS ", 5)) {
                if (ftp->ftp_passok == FTPXY_USOK_1) {
                        ftp->ftp_passok = FTPXY_PASS_1;
                        ftp->ftp_incok = 1;
                } else if (ftp->ftp_passok == FTPXY_USOK_2) {
                        ftp->ftp_passok = FTPXY_PASS_2;
                        ftp->ftp_incok = 1;
                }
        } else if ((ftp->ftp_passok == FTPXY_AUOK_1) &&
                   !strncmp(cmd, "ADAT ", 5)) {
                ftp->ftp_passok = FTPXY_ADAT_1;
                ftp->ftp_incok = 1;
        } else if ((ftp->ftp_passok == FTPXY_PAOK_1 ||
                    ftp->ftp_passok == FTPXY_PAOK_2) &&
                 !strncmp(cmd, "ACCT ", 5)) {
                ftp->ftp_passok = FTPXY_ACCT_1;
                ftp->ftp_incok = 1;
        } else if ((ftp->ftp_passok == FTPXY_GO) &&
                   !softf->ipf_p_ftp_pasvonly &&
                 !strncmp(cmd, "PORT ", 5)) {
                inc = ipf_p_ftp_port(softf, fin, ip, nat, ftp, dlen);
        } else if ((ftp->ftp_passok == FTPXY_GO) &&
                   !softf->ipf_p_ftp_pasvonly &&
                 !strncmp(cmd, "EPRT ", 5)) {
                inc = ipf_p_ftp_eprt(softf, fin, ip, nat, ftp, dlen);
        } else if (softf->ipf_p_ftp_insecure &&
                   !softf->ipf_p_ftp_pasvonly &&
                   !strncmp(cmd, "PORT ", 5)) {
                inc = ipf_p_ftp_port(softf, fin, ip, nat, ftp, dlen);
        }
        if (softf->ipf_p_ftp_debug & DEBUG_PARSE)
                printf("ipf_p_ftp_client: cmd[%s] passok %d incok %d inc %d\n",
                       cmd, ftp->ftp_passok, ftp->ftp_incok, inc);

        DT2(ftp_client_passok, char *, cmd, int, ftp->ftp_passok);
        while ((*rptr++ != '\n') && (rptr < wptr))
                ;
        f->ftps_rptr = rptr;
        return (inc);
}


int
ipf_p_ftp_pasv(ipf_ftp_softc_t *softf, fr_info_t *fin, ip_t *ip, nat_t *nat,
        ftpinfo_t *ftp, int dlen)
{
        u_int a1, a2, a3, a4, data_ip;
        char newbuf[IPF_FTPBUFSZ];
        const char *brackets[2];
        u_short a5, a6;
        ftpside_t *f;
        char *s;

        if ((softf->ipf_p_ftp_forcepasv != 0) &&
            (ftp->ftp_side[0].ftps_cmd != FTPXY_C_PASV)) {
                DT2(ftp_PASV_error_state, nat_t *, nat, ftpinfo_t *, ftp);
                if (softf->ipf_p_ftp_debug & DEBUG_ERROR)
                        printf("ipf_p_ftp_pasv:ftps_cmd(%d) != FTPXY_C_PASV\n",
                               ftp->ftp_side[0].ftps_cmd);
                return (0);
        }

        f = &ftp->ftp_side[1];

#define PASV_REPLEN     24
        /*
         * Check for PASV reply message.
         */
        if (dlen < IPF_MIN227LEN) {
                DT3(ftp_PASV_error_short, nat_t *, nat, ftpinfo_t *, ftp,
                    int, dlen);
                if (softf->ipf_p_ftp_debug & DEBUG_ERROR)
                        printf("ipf_p_ftp_pasv:dlen(%d) < IPF_MIN227LEN\n",
                               dlen);
                return (0);
        } else if (strncmp(f->ftps_rptr,
                           "227 Entering Passive Mod", PASV_REPLEN)) {
                DT2(ftp_PASV_error_string, nat_t *, nat, ftpinfo_t *, ftp);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_pasv:%d reply wrong\n", 227);
                return (0);
        }

        brackets[0] = "";
        brackets[1] = "";
        /*
         * Skip the PASV reply + space
         */
        s = f->ftps_rptr + PASV_REPLEN;
        while (*s && !ISDIGIT(*s)) {
                if (*s == '(') {
                        brackets[0] = "(";
                        brackets[1] = ")";
                }
                s++;
        }

        /*
         * Pick out the address components, two at a time.
         */
        a1 = ipf_p_ftp_atoi(&s);
        if (s == NULL) {
                DT2(ftp_PASV_error_atoi_1, nat_t *, nat, ftpside_t *, f);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_pasv:ipf_p_ftp_atoi(%d) failed\n", 1);
                return (0);
        }
        a2 = ipf_p_ftp_atoi(&s);
        if (s == NULL) {
                DT2(ftp_PASV_error_atoi_2, nat_t *, nat, ftpside_t *, f);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_pasv:ipf_p_ftp_atoi(%d) failed\n", 2);
                return (0);
        }

        /*
         * check that IP address in the PASV reply is the same as the
         * sender of the command - prevents using PASV for port scanning.
         */
        a1 <<= 16;
        a1 |= a2;

        if (((nat->nat_dir == NAT_INBOUND) &&
             (a1 != ntohl(nat->nat_ndstaddr))) ||
            ((nat->nat_dir == NAT_OUTBOUND) &&
             (a1 != ntohl(nat->nat_odstaddr)))) {
                DT3(ftp_PASV_error_address, nat_t *, nat, ftpside_t *, f,
                    u_int, a1);
                if (softf->ipf_p_ftp_debug & DEBUG_ERROR)
                        printf("ipf_p_ftp_pasv:%s != nat->nat_oip\n", "a1");
                return (0);
        }

        a5 = ipf_p_ftp_atoi(&s);
        if (s == NULL) {
                DT2(ftp_PASV_error_atoi_3, nat_t *, nat, ftpside_t *, f);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_pasv:ipf_p_ftp_atoi(%d) failed\n", 3);
                return (0);
        }

        if (*s == ')')
                s++;
        if (*s == '.')
                s++;
        if (*s == '\n')
                s--;
        /*
         * check for CR-LF at the end.
         */
        if ((*s != '\r') || (*(s + 1) != '\n')) {
                DT(pasv_missing_crlf);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_pasv:missing %s", "cr-lf\n");
                return (0);
        }
        s += 2;

        a6 = a5 & 0xff;
        a5 >>= 8;
        /*
         * Calculate new address parts for 227 reply
         */
        if (nat->nat_dir == NAT_INBOUND) {
                data_ip = nat->nat_odstaddr;
                a1 = ntohl(data_ip);
        } else
                data_ip = htonl(a1);

        a2 = (a1 >> 16) & 0xff;
        a3 = (a1 >> 8) & 0xff;
        a4 = a1 & 0xff;
        a1 >>= 24;

        (void) snprintf(newbuf, sizeof(newbuf), "%s %s%u,%u,%u,%u,%u,%u%s\r\n",
                "227 Entering Passive Mode", brackets[0], a1, a2, a3, a4,
                a5, a6, brackets[1]);
        return (ipf_p_ftp_pasvreply(softf, fin, ip, nat, ftp, (a5 << 8 | a6),
                                   newbuf, s));
}

int
ipf_p_ftp_pasvreply(ipf_ftp_softc_t *softf, fr_info_t *fin, ip_t *ip,
        nat_t *nat, ftpinfo_t *ftp, u_int port, char *newmsg, char *s)
{
        int inc, off, nflags;
        tcphdr_t *tcp, tcph, *tcp2;
        ipf_main_softc_t *softc;
        ipf_nat_softc_t *softn;
        size_t nlen, olen;
#ifdef USE_INET6
        ip6_t *ip6;
#endif
        ipnat_t *ipn;
        fr_info_t fi;
        ftpside_t *f;
        nat_t *nat2;
        mb_t *m;

        softc = fin->fin_main_soft;
        softn = softc->ipf_nat_soft;

        if ((ftp->ftp_pendnat != NULL) || (ftp->ftp_pendstate != NULL))
                ipf_p_ftp_setpending(softc, ftp);

        m = fin->fin_m;
        tcp = (tcphdr_t *)fin->fin_dp;
        off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;

        tcp2 = &tcph;
        inc = 0;

        f = &ftp->ftp_side[1];
        olen = s - f->ftps_rptr;
        nlen = strlen(newmsg);
        inc = nlen - olen;
        if ((inc + fin->fin_plen) > 65535) {
                DT3(ftp_PASV_error_inc, nat_t *, nat, ftpside_t *, f,
                    int, inc);
                if (softf->ipf_p_ftp_debug & DEBUG_ERROR)
                        printf("ipf_p_ftp_pasv:inc(%d) + ip->ip_len > 65535\n",
                               inc);
                return (0);
        }

        ipn = ipf_proxy_rule_fwd(nat);
        if (ipn == NULL)
                return (APR_ERR(1));
        ipn->in_use = 0;

        /*
         * Add skeleton NAT entry for connection which will come back the
         * other way.
         */
        bzero((char *)tcp2, sizeof(*tcp2));
        bcopy((char *)fin, (char *)&fi, sizeof(fi));
        fi.fin_flx |= FI_IGNORE;
        fi.fin_data[0] = 0;
        fi.fin_data[1] = port;
        nflags = IPN_TCP|SI_W_SPORT;

        fi.fin_fr = &ftppxyfr;
        fi.fin_dp = (char *)tcp2;
        fi.fin_out = 1 - fin->fin_out;
        fi.fin_dlen = sizeof(*tcp2);
        fi.fin_src6 = nat->nat_osrc6;
        fi.fin_dst6 = nat->nat_odst6;
        fi.fin_plen = fi.fin_hlen + sizeof(*tcp);
        fi.fin_flx &= FI_LOWTTL|FI_FRAG|FI_TCPUDP|FI_OPTIONS|FI_IGNORE;

        TCP_OFF_A(tcp2, 5);
        tcp_set_flags(tcp2, TH_SYN);
        tcp2->th_win = htons(8192);
        tcp2->th_dport = htons(port);

        MUTEX_ENTER(&softn->ipf_nat_new);
#ifdef USE_INET6
        if (nat->nat_v[0] == 6)
                nat2 = ipf_nat6_add(&fi, ipn, &ftp->ftp_pendnat,
                                    nflags, nat->nat_dir);
        else
#endif
                nat2 = ipf_nat_add(&fi, ipn, &ftp->ftp_pendnat,
                                   nflags, nat->nat_dir);
        MUTEX_EXIT(&softn->ipf_nat_new);

        if (nat2 == NULL) {
                KFREES(ipn, ipn->in_size);
                return (APR_ERR(1));
        }

        (void) ipf_nat_proto(&fi, nat2, IPN_TCP);
        MUTEX_ENTER(&nat2->nat_lock);
        ipf_nat_update(&fi, nat2);
        MUTEX_EXIT(&nat2->nat_lock);
        fi.fin_ifp = NULL;
        if (nat->nat_dir == NAT_INBOUND) {
#ifdef USE_INET6
                if (nat->nat_v[0] == 6)
                        fi.fin_dst6 = nat->nat_ndst6;
                else
#endif
                        fi.fin_daddr = nat->nat_ndstaddr;
        }
        if (ipf_state_add(softc, &fi, (ipstate_t **)&ftp->ftp_pendstate,
                          SI_W_SPORT) != 0)
                ipf_nat_setpending(softc, nat2);

#if !defined(_KERNEL)
        M_ADJ(m, inc);
#else
        /*
         * m_adj takes care of pkthdr.len, if required and treats inc<0 to
         * mean remove -len bytes from the end of the packet.
         * The mbuf chain will be extended if necessary by m_copyback().
         */
        if (inc < 0)
                M_ADJ(m, inc);
#endif /* !defined(_KERNEL) */
        COPYBACK(m, off, nlen, newmsg);
        fin->fin_flx |= FI_DOCKSUM;

        if (inc != 0) {
                fin->fin_plen += inc;
                fin->fin_dlen += inc;
#ifdef USE_INET6
                if (nat->nat_v[0] == 6) {
                        ip6 = (ip6_t *)fin->fin_ip;
                        u_short len = ntohs(ip6->ip6_plen) + inc;
                        ip6->ip6_plen = htons(len);
                } else
#endif
                        ip->ip_len = htons(fin->fin_plen);
        }

        return (APR_INC(inc));
}


int
ipf_p_ftp_server(ipf_ftp_softc_t *softf, fr_info_t *fin, ip_t *ip, nat_t *nat,
        ftpinfo_t *ftp, int dlen)
{
        char *rptr, *wptr;
        ftpside_t *f;
        int inc;

        inc = 0;
        f = &ftp->ftp_side[1];
        rptr = f->ftps_rptr;
        wptr = f->ftps_wptr;

        DT2(ftp_server_response, char *, rptr, int, ftp->ftp_passok);
        if (*rptr == ' ')
                goto server_cmd_ok;
        if (!ISDIGIT(*rptr) || !ISDIGIT(*(rptr + 1)) || !ISDIGIT(*(rptr + 2)))
                return (0);
        if (softf->ipf_p_ftp_debug & DEBUG_PARSE)
                printf("ipf_p_ftp_server_1: cmd[%4.4s] passok %d\n",
                       rptr, ftp->ftp_passok);
        if (ftp->ftp_passok == FTPXY_GO) {
                if (!strncmp(rptr, "227 ", 4))
                        inc = ipf_p_ftp_pasv(softf, fin, ip, nat, ftp, dlen);
                else if (!strncmp(rptr, "229 ", 4))
                        inc = ipf_p_ftp_epsv(softf, fin, ip, nat, ftp, dlen);
                else if (strncmp(rptr, "200", 3)) {
                        /*
                         * 200 is returned for a successful command.
                         */
                        ;
                }
        } else if (softf->ipf_p_ftp_insecure && !strncmp(rptr, "227 ", 4)) {
                inc = ipf_p_ftp_pasv(softf, fin, ip, nat, ftp, dlen);
        } else if (softf->ipf_p_ftp_insecure && !strncmp(rptr, "229 ", 4)) {
                inc = ipf_p_ftp_epsv(softf, fin, ip, nat, ftp, dlen);
        } else if (*rptr == '5' || *rptr == '4')
                ftp->ftp_passok = FTPXY_INIT;
        else if (ftp->ftp_incok) {
                if (*rptr == '3') {
                        if (ftp->ftp_passok == FTPXY_ACCT_1)
                                ftp->ftp_passok = FTPXY_GO;
                        else
                                ftp->ftp_passok++;
                } else if (*rptr == '2') {
                        switch (ftp->ftp_passok)
                        {
                        case FTPXY_USER_1 :
                        case FTPXY_USER_2 :
                        case FTPXY_PASS_1 :
                        case FTPXY_PASS_2 :
                        case FTPXY_ACCT_1 :
                                ftp->ftp_passok = FTPXY_GO;
                                break;
                        default :
                                ftp->ftp_passok += 3;
                                break;
                        }
                }
        }
        ftp->ftp_incok = 0;
server_cmd_ok:
        if (softf->ipf_p_ftp_debug & DEBUG_PARSE)
                printf("ipf_p_ftp_server_2: cmd[%4.4s] passok %d\n",
                       rptr, ftp->ftp_passok);
        DT3(ftp_server_passok, char *,rptr, int, ftp->ftp_incok,
            int, ftp->ftp_passok);

        while ((*rptr++ != '\n') && (rptr < wptr))
                ;
        f->ftps_rptr = rptr;
        return (inc);
}


/*
 * 0 FTPXY_JUNK_OK
 * 1 FTPXY_JUNK_BAD
 * 2 FTPXY_JUNK_EOL
 * 3 FTPXY_JUNK_CONT
 *
 * Look to see if the buffer starts with something which we recognise as
 * being the correct syntax for the FTP protocol.
 */
int
ipf_p_ftp_client_valid(ipf_ftp_softc_t *softf, ftpside_t *ftps, char *buf,
        size_t len)
{
        register char *s, c, pc;
        register size_t i = len;
        char cmd[5];

        s = buf;

        if (ftps->ftps_junk == FTPXY_JUNK_BAD)
                return (FTPXY_JUNK_BAD);

        if (i < 5) {
                DT1(client_valid, int, i);
                if (softf->ipf_p_ftp_debug & DEBUG_ERROR)
                        printf("ipf_p_ftp_client_valid:i(%d) < 5\n", (int)i);
                return (2);
        }

        i--;
        c = *s++;

        if (ISALPHA(c)) {
                cmd[0] = TOUPPER(c);
                c = *s++;
                i--;
                if (ISALPHA(c)) {
                        cmd[1] = TOUPPER(c);
                        c = *s++;
                        i--;
                        if (ISALPHA(c)) {
                                cmd[2] = TOUPPER(c);
                                c = *s++;
                                i--;
                                if (ISALPHA(c)) {
                                        cmd[3] = TOUPPER(c);
                                        c = *s++;
                                        i--;
                                        if ((c != ' ') && (c != '\r'))
                                                goto bad_client_command;
                                } else if ((c != ' ') && (c != '\r'))
                                        goto bad_client_command;
                        } else
                                goto bad_client_command;
                } else
                        goto bad_client_command;
        } else {
bad_client_command:
                DT4(client_junk, int, len, int, i, int, c, char *, buf);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("%s:bad:junk %d len %d/%d c 0x%x buf [%*.*s]\n",
                               "ipf_p_ftp_client_valid",
                               ftps->ftps_junk, (int)len, (int)i, c,
                               (int)len, (int)len, buf);
                return (FTPXY_JUNK_BAD);
        }

        for (; i; i--) {
                pc = c;
                c = *s++;
                if ((pc == '\r') && (c == '\n')) {
                        cmd[4] = '\0';
                        if (!strcmp(cmd, "PASV")) {
                                ftps->ftps_cmd = FTPXY_C_PASV;
                        } else if (!strcmp(cmd, "EPSV")) {
                                ftps->ftps_cmd = FTPXY_C_EPSV;
                        } else {
                                ftps->ftps_cmd = 0;
                        }
                        return (0);
                }
        }
#if !defined(_KERNEL)
        printf("ipf_p_ftp_client_valid:junk after cmd[%*.*s]\n",
               (int)len, (int)len, buf);
#endif
        return (FTPXY_JUNK_EOL);
}


int
ipf_p_ftp_server_valid(ipf_ftp_softc_t *softf, ftpside_t *ftps, char *buf,
        size_t len)
{
        register char *s, c, pc;
        register size_t i = len;
        int cmd;

        s = buf;
        cmd = 0;

        if (ftps->ftps_junk == FTPXY_JUNK_BAD)
                return (FTPXY_JUNK_BAD);

        if (i < 5) {
                DT1(server_valid, int, i);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_servert_valid:i(%d) < 5\n", (int)i);
                return (2);
        }

        c = *s++;
        i--;
        if (c == ' ') {
                cmd = -1;
                goto search_eol;
        }

        if (ISDIGIT(c)) {
                cmd = (c - '0') * 100;
                c = *s++;
                i--;
                if (ISDIGIT(c)) {
                        cmd += (c - '0') * 10;
                        c = *s++;
                        i--;
                        if (ISDIGIT(c)) {
                                cmd += (c - '0');
                                c = *s++;
                                i--;
                                if ((c != '-') && (c != ' '))
                                        goto bad_server_command;
                                if (c == '-')
                                        return (FTPXY_JUNK_CONT);
                        } else
                                goto bad_server_command;
                } else
                        goto bad_server_command;
        } else {
bad_server_command:
                DT4(server_junk, int len, buf, int, i, int, c, char *, buf);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_INFO)
                        printf("%s:bad:junk %d len %d/%d c 0x%x buf [%*.*s]\n",
                               "ipf_p_ftp_server_valid",
                               ftps->ftps_junk, (int)len, (int)i,
                               c, (int)len, (int)len, buf);
                if (ftps->ftps_junk == FTPXY_JUNK_CONT)
                        return (FTPXY_JUNK_CONT);
                return (FTPXY_JUNK_BAD);
        }
search_eol:
        for (; i; i--) {
                pc = c;
                c = *s++;
                if ((pc == '\r') && (c == '\n')) {
                        if (cmd == -1) {
                                if (ftps->ftps_junk == FTPXY_JUNK_CONT)
                                        return (FTPXY_JUNK_CONT);
                        } else {
                                ftps->ftps_cmd = cmd;
                        }
                        return (FTPXY_JUNK_OK);
                }
        }

        DT2(junk_eol, int, len, char *, buf);
        if (softf->ipf_p_ftp_debug & DEBUG_PARSE_INFO)
                printf("ipf_p_ftp_server_valid:junk after cmd[%*.*s]\n",
                       (int)len, (int)len, buf);
        return (FTPXY_JUNK_EOL);
}


int
ipf_p_ftp_valid(ipf_ftp_softc_t *softf, ftpinfo_t *ftp, int side, char *buf,
        size_t len)
{
        ftpside_t *ftps;

        ftps = &ftp->ftp_side[side];

        if (side == 0)
                return (ipf_p_ftp_client_valid(softf, ftps, buf, len));
        else
                return (ipf_p_ftp_server_valid(softf, ftps, buf, len));
}


/*
 * For map rules, the following applies:
 * rv == 0 for outbound processing,
 * rv == 1 for inbound processing.
 * For rdr rules, the following applies:
 * rv == 0 for inbound processing,
 * rv == 1 for outbound processing.
 */
int
ipf_p_ftp_process(ipf_ftp_softc_t *softf, fr_info_t *fin, nat_t *nat,
        ftpinfo_t *ftp, int rv)
{
        int mlen, len, off, inc, i, sel, sel2, ok, ackoff, seqoff, retry;
        char *rptr, *wptr, *s;
        u_32_t thseq, thack;
        ap_session_t *aps;
        ftpside_t *f, *t;
        tcphdr_t *tcp;
        ip_t *ip;
        mb_t *m;

        m = fin->fin_m;
        ip = fin->fin_ip;
        tcp = (tcphdr_t *)fin->fin_dp;
        off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;

        f = &ftp->ftp_side[rv];
        t = &ftp->ftp_side[1 - rv];
        thseq = ntohl(tcp->th_seq);
        thack = ntohl(tcp->th_ack);
        mlen = MSGDSIZE(m) - off;

        DT3(process_debug, tcphdr_t *, tcp, int, off, int, mlen);
        if (softf->ipf_p_ftp_debug & DEBUG_INFO)
                printf("ipf_p_ftp_process: %d:%d,%d, mlen %d flags %x\n",
                       fin->fin_out, fin->fin_sport, fin->fin_dport,
                       mlen, tcp_get_flags(tcp));

        if ((mlen == 0) && ((tcp_get_flags(tcp) & TH_OPENING) == TH_OPENING)) {
                f->ftps_seq[0] = thseq + 1;
                t->ftps_seq[0] = thack;
                return (0);
        } else if (mlen < 0) {
                return (0);
        }

        aps = nat->nat_aps;

        sel = aps->aps_sel[1 - rv];
        sel2 = aps->aps_sel[rv];
        if (rv == 1) {
                seqoff = aps->aps_seqoff[sel];
                if (aps->aps_seqmin[sel] > seqoff + thseq)
                        seqoff = aps->aps_seqoff[!sel];
                ackoff = aps->aps_ackoff[sel2];
                if (aps->aps_ackmin[sel2] > ackoff + thack)
                        ackoff = aps->aps_ackoff[!sel2];
        } else {
                seqoff = aps->aps_ackoff[sel];
                if (softf->ipf_p_ftp_debug & DEBUG_INFO)
                        printf("seqoff %d thseq %x ackmin %x\n", seqoff, thseq,
                               aps->aps_ackmin[sel]);
                if (aps->aps_ackmin[sel] > seqoff + thseq)
                        seqoff = aps->aps_ackoff[!sel];

                ackoff = aps->aps_seqoff[sel2];
                if (softf->ipf_p_ftp_debug & DEBUG_INFO)
                        printf("ackoff %d thack %x seqmin %x\n", ackoff, thack,
                               aps->aps_seqmin[sel2]);
                if (ackoff > 0) {
                        if (aps->aps_seqmin[sel2] > ackoff + thack)
                                ackoff = aps->aps_seqoff[!sel2];
                } else {
                        if (aps->aps_seqmin[sel2] > thack)
                                ackoff = aps->aps_seqoff[!sel2];
                }
        }
        if (softf->ipf_p_ftp_debug & DEBUG_INFO) {
                printf("%s: %x seq %x/%d ack %x/%d len %d/%d off %d\n",
                       rv ? "IN" : "OUT", tcp_get_flags(tcp), thseq, seqoff,
                       thack, ackoff, mlen, fin->fin_plen, off);
                printf("sel %d seqmin %x/%x offset %d/%d\n", sel,
                       aps->aps_seqmin[sel], aps->aps_seqmin[sel2],
                       aps->aps_seqoff[sel], aps->aps_seqoff[sel2]);
                printf("sel %d ackmin %x/%x offset %d/%d\n", sel2,
                       aps->aps_ackmin[sel], aps->aps_ackmin[sel2],
                       aps->aps_ackoff[sel], aps->aps_ackoff[sel2]);
        }

        /*
         * XXX - Ideally, this packet should get dropped because we now know
         * that it is out of order (and there is no real danger in doing so
         * apart from causing packets to go through here ordered).
         */
        if (softf->ipf_p_ftp_debug & DEBUG_INFO) {
                printf("rv %d t:seq[0] %x seq[1] %x %d/%d\n",
                       rv, t->ftps_seq[0], t->ftps_seq[1], seqoff, ackoff);
        }

        ok = 0;
        if (t->ftps_seq[0] == 0) {
                t->ftps_seq[0] = thack;
                ok = 1;
        } else {
                if (ackoff == 0) {
                        if (t->ftps_seq[0] == thack)
                                ok = 1;
                        else if (t->ftps_seq[1] == thack) {
                                t->ftps_seq[0] = thack;
                                ok = 1;
                        }
                } else {
                        if (t->ftps_seq[0] + ackoff == thack) {
                                t->ftps_seq[0] = thack;
                                ok = 1;
                        } else if (t->ftps_seq[0] == thack + ackoff) {
                                t->ftps_seq[0] = thack + ackoff;
                                ok = 1;
                        } else if (t->ftps_seq[1] + ackoff == thack) {
                                t->ftps_seq[0] = thack;
                                ok = 1;
                        } else if (t->ftps_seq[1] == thack + ackoff) {
                                t->ftps_seq[0] = thack + ackoff;
                                ok = 1;
                        }
                }
        }

        if (softf->ipf_p_ftp_debug & DEBUG_INFO) {
                if (!ok)
                        printf("%s ok\n", "not");
        }

        if (!mlen) {
                if (t->ftps_seq[0] + ackoff != thack &&
                    t->ftps_seq[1] + ackoff != thack) {
                        DT3(thack, ftpside_t *t, t, int, ackoff, u_32_t, thack);
                        if (softf->ipf_p_ftp_debug & DEBUG_ERROR) {
                                printf("%s:seq[0](%u) + (%d) != (%u)\n",
                                       "ipf_p_ftp_process", t->ftps_seq[0],
                                       ackoff, thack);
                                printf("%s:seq[1](%u) + (%d) != (%u)\n",
                                       "ipf_p_ftp_process", t->ftps_seq[1],
                                       ackoff, thack);
                        }
                        return (APR_ERR(1));
                }

                if (softf->ipf_p_ftp_debug & DEBUG_PARSE) {
                        printf("ipf_p_ftp_process:f:seq[0] %x seq[1] %x\n",
                                f->ftps_seq[0], f->ftps_seq[1]);
                }

                if (tcp_get_flags(tcp) & TH_FIN) {
                        if (thseq == f->ftps_seq[1]) {
                                f->ftps_seq[0] = f->ftps_seq[1] - seqoff;
                                f->ftps_seq[1] = thseq + 1 - seqoff;
                        } else {
                                DT2(thseq, ftpside_t *t, t, u_32_t, thseq);
                                if (softf->ipf_p_ftp_debug & DEBUG_ERROR) {
                                        printf("FIN: thseq %x seqoff %d ftps_seq %x\n",
                                               thseq, seqoff, f->ftps_seq[0]);
                                }
                                return (APR_ERR(1));
                        }
                }
                f->ftps_len = 0;
                return (0);
        }

        ok = 0;
        if ((thseq == f->ftps_seq[0]) || (thseq == f->ftps_seq[1])) {
                ok = 1;
        /*
         * Retransmitted data packet.
         */
        } else if ((thseq + mlen == f->ftps_seq[0]) ||
                   (thseq + mlen == f->ftps_seq[1])) {
                ok = 1;
        }

        if (ok == 0) {
                DT3(ok_0, ftpside_t *, f, u_32_t, thseq, int, mlen);
                inc = thseq - f->ftps_seq[0];
                if (softf->ipf_p_ftp_debug & DEBUG_ERROR) {
                        printf("inc %d sel %d rv %d\n", inc, sel, rv);
                        printf("th_seq %x ftps_seq %x/%x\n",
                               thseq, f->ftps_seq[0], f->ftps_seq[1]);
                        printf("ackmin %x ackoff %d\n", aps->aps_ackmin[sel],
                               aps->aps_ackoff[sel]);
                        printf("seqmin %x seqoff %d\n", aps->aps_seqmin[sel],
                               aps->aps_seqoff[sel]);
                }

                return (APR_ERR(1));
        }

        inc = 0;
        rptr = f->ftps_rptr;
        wptr = f->ftps_wptr;
        f->ftps_seq[0] = thseq;
        f->ftps_seq[1] = f->ftps_seq[0] + mlen;
        f->ftps_len = mlen;

        while (mlen > 0) {
                len = MIN(mlen, sizeof(f->ftps_buf) - (wptr - rptr));
                if (len == 0)
                        break;
                COPYDATA(m, off, len, wptr);
                mlen -= len;
                off += len;
                wptr += len;

whilemore:
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE)
                        printf("%s:len %d/%d off %d wptr %lx junk %d [%*.*s]\n",
                               "ipf_p_ftp_process",
                               len, mlen, off, (u_long)wptr, f->ftps_junk,
                               len, len, rptr);

                f->ftps_wptr = wptr;
                if (f->ftps_junk != FTPXY_JUNK_OK) {
                        i = f->ftps_junk;
                        f->ftps_junk = ipf_p_ftp_valid(softf, ftp, rv, rptr,
                                                      wptr - rptr);
                        DT2(junk_transit, int, i, int, f->ftps_junk);

                        if (softf->ipf_p_ftp_debug & DEBUG_PARSE)
                                printf("%s:junk %d -> %d\n",
                                       "ipf_p_ftp_process", i, f->ftps_junk);

                        if (f->ftps_junk == FTPXY_JUNK_BAD) {
                                DT(buffer_full);
                                if (wptr - rptr == sizeof(f->ftps_buf)) {
                                        if (softf->ipf_p_ftp_debug &
                                            DEBUG_PARSE_INFO)
                                                printf("%s:full buffer\n",
                                                       "ipf_p_ftp_process");
                                        f->ftps_rptr = f->ftps_buf;
                                        f->ftps_wptr = f->ftps_buf;
                                        rptr = f->ftps_rptr;
                                        wptr = f->ftps_wptr;
                                        continue;
                                }
                        }
                }

                while ((f->ftps_junk == FTPXY_JUNK_OK) && (wptr > rptr)) {
                        len = wptr - rptr;
                        f->ftps_junk = ipf_p_ftp_valid(softf, ftp, rv,
                                                       rptr, len);
                        DT5(junk_ftp_valid, int, len, int, rv, u_long, rptr,
                            u_long, wptr, int, f->ftps_junk);

                        if (softf->ipf_p_ftp_debug & DEBUG_PARSE) {
                                printf("%s=%d len %d rv %d ptr %lx/%lx ",
                                       "ipf_p_ftp_valid",
                                       f->ftps_junk, len, rv, (u_long)rptr,
                                       (u_long)wptr);
                                printf("buf [%*.*s]\n", len, len, rptr);
                        }

                        if (f->ftps_junk == FTPXY_JUNK_OK) {
                                f->ftps_cmds++;
                                f->ftps_rptr = rptr;
                                if (rv)
                                        inc += ipf_p_ftp_server(softf, fin, ip,
                                                                nat, ftp, len);
                                else
                                        inc += ipf_p_ftp_client(softf, fin, ip,
                                                                nat, ftp, len);
                                rptr = f->ftps_rptr;
                                wptr = f->ftps_wptr;
                        }
                }

                /*
                 * Off to a bad start so lets just forget about using the
                 * ftp proxy for this connection.
                 */
                if ((f->ftps_cmds == 0) && (f->ftps_junk == FTPXY_JUNK_BAD)) {
                        /* f->ftps_seq[1] += inc; */

                        DT(ftp_junk_cmd);
                        if (softf->ipf_p_ftp_debug & DEBUG_ERROR)
                                printf("%s:cmds == 0 junk == 1\n",
                                       "ipf_p_ftp_process");
                        return (APR_ERR(2));
                }

                retry = 0;
                if ((f->ftps_junk != FTPXY_JUNK_OK) && (rptr < wptr)) {
                        for (s = rptr; s < wptr; s++) {
                                if ((*s == '\r') && (s + 1 < wptr) &&
                                    (*(s + 1) == '\n')) {
                                        rptr = s + 2;
                                        retry = 1;
                                        if (f->ftps_junk != FTPXY_JUNK_CONT)
                                                f->ftps_junk = FTPXY_JUNK_OK;
                                        break;
                                }
                        }
                }

                if (rptr == wptr) {
                        rptr = wptr = f->ftps_buf;
                } else {
                        /*
                         * Compact the buffer back to the start.  The junk
                         * flag should already be set and because we're not
                         * throwing away any data, it is preserved from its
                         * current state.
                         */
                        if (rptr > f->ftps_buf) {
                                bcopy(rptr, f->ftps_buf, wptr - rptr);
                                wptr -= rptr - f->ftps_buf;
                                rptr = f->ftps_buf;
                        }
                }
                f->ftps_rptr = rptr;
                f->ftps_wptr = wptr;
                if (retry)
                        goto whilemore;
        }

        /* f->ftps_seq[1] += inc; */
        if (tcp_get_flags(tcp) & TH_FIN)
                f->ftps_seq[1]++;
        if (softf->ipf_p_ftp_debug & DEBUG_PARSE_INFO) {
                mlen = MSGDSIZE(m);
                mlen -= off;
                printf("ftps_seq[1] = %x inc %d len %d\n",
                       f->ftps_seq[1], inc, mlen);
        }

        f->ftps_rptr = rptr;
        f->ftps_wptr = wptr;
        return (APR_INC(inc));
}


int
ipf_p_ftp_out(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat)
{
        ipf_ftp_softc_t *softf = arg;
        ftpinfo_t *ftp;
        int rev;

        ftp = aps->aps_data;
        if (ftp == NULL)
                return (0);

        rev = (nat->nat_dir == NAT_OUTBOUND) ? 0 : 1;
        if (ftp->ftp_side[1 - rev].ftps_ifp == NULL)
                ftp->ftp_side[1 - rev].ftps_ifp = fin->fin_ifp;

        return (ipf_p_ftp_process(softf, fin, nat, ftp, rev));
}


int
ipf_p_ftp_in(void *arg, fr_info_t *fin, ap_session_t *aps, nat_t *nat)
{
        ipf_ftp_softc_t *softf = arg;
        ftpinfo_t *ftp;
        int rev;

        ftp = aps->aps_data;
        if (ftp == NULL)
                return (0);

        rev = (nat->nat_dir == NAT_OUTBOUND) ? 0 : 1;
        if (ftp->ftp_side[rev].ftps_ifp == NULL)
                ftp->ftp_side[rev].ftps_ifp = fin->fin_ifp;

        return (ipf_p_ftp_process(softf, fin, nat, ftp, 1 - rev));
}


/*
 * ipf_p_ftp_atoi - implement a version of atoi which processes numbers in
 * pairs separated by commas (which are expected to be in the range 0 - 255),
 * returning a 16 bit number combining either side of the , as the MSB and
 * LSB.
 */
u_short
ipf_p_ftp_atoi(char **ptr)
{
        register char *s = *ptr, c;
        register u_char i = 0, j = 0;

        while (((c = *s++) != '\0') && ISDIGIT(c)) {
                i *= 10;
                i += c - '0';
        }
        if (c != ',') {
                *ptr = NULL;
                return (0);
        }
        while (((c = *s++) != '\0') && ISDIGIT(c)) {
                j *= 10;
                j += c - '0';
        }
        *ptr = s;
        i &= 0xff;
        j &= 0xff;
        return (i << 8) | j;
}


int
ipf_p_ftp_eprt(ipf_ftp_softc_t *softf, fr_info_t *fin, ip_t *ip, nat_t *nat,
        ftpinfo_t *ftp, int dlen)
{
        ftpside_t *f;

        /*
         * Check for client sending out EPRT message.
         */
        if (dlen < IPF_MINEPRTLEN) {
                DT1(epert_dlen, int, dlen);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_eprt:dlen(%d) < IPF_MINEPRTLEN\n",
                                dlen);
                return (0);
        }

        /*
         * Parse the EPRT command.  Format is:
         * "EPRT |1|1.2.3.4|2000|" for IPv4 and
         * "EPRT |2|ef00::1:2|2000|" for IPv6
         */
        f = &ftp->ftp_side[0];
        if (f->ftps_rptr[5] != '|')
                return (0);
        if (f->ftps_rptr[5] == f->ftps_rptr[7]) {
                if (f->ftps_rptr[6] == '1' && nat->nat_v[0] == 4)
                        return (ipf_p_ftp_eprt4(softf, fin, ip, nat, ftp, dlen));
#ifdef USE_INET6
                if (f->ftps_rptr[6] == '2' && nat->nat_v[0] == 6)
                        return (ipf_p_ftp_eprt6(softf, fin, ip, nat, ftp, dlen));
#endif
        }
        return (0);
}


int
ipf_p_ftp_eprt4(ipf_ftp_softc_t *softf, fr_info_t *fin, ip_t *ip, nat_t *nat,
        ftpinfo_t *ftp, int dlen)
{
        int a1, a2, a3, a4, port, olen, nlen, inc, off;
        char newbuf[IPF_FTPBUFSZ];
        char *s, c, delim;
        u_32_t addr, i;
        tcphdr_t *tcp;
        ftpside_t *f;
        mb_t *m;

        m = fin->fin_m;
        tcp = (tcphdr_t *)fin->fin_dp;
        off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
        f = &ftp->ftp_side[0];
        delim = f->ftps_rptr[5];
        s = f->ftps_rptr + 8;

        /*
         * get the IP address.
         */
        i = 0;
        while (((c = *s++) != '\0') && ISDIGIT(c)) {
                i *= 10;
                i += c - '0';
        }
        if (i > 255)
                return (0);
        if (c != '.')
                return (0);
        addr = (i << 24);

        i = 0;
        while (((c = *s++) != '\0') && ISDIGIT(c)) {
                i *= 10;
                i += c - '0';
        }
        if (i > 255)
                return (0);
        if (c != '.')
                return (0);
        addr |= (addr << 16);

        i = 0;
        while (((c = *s++) != '\0') && ISDIGIT(c)) {
                i *= 10;
                i += c - '0';
        }
        if (i > 255)
                return (0);
        if (c != '.')
                return (0);
        addr |= (addr << 8);

        i = 0;
        while (((c = *s++) != '\0') && ISDIGIT(c)) {
                i *= 10;
                i += c - '0';
        }
        if (i > 255)
                return (0);
        if (c != delim)
                return (0);
#if 0
        addr |= (addr << 0);
#endif

        /*
         * Get the port number
         */
        i = 0;
        while (((c = *s++) != '\0') && ISDIGIT(c)) {
                i *= 10;
                i += c - '0';
        }
        if (i > 65535)
                return (0);
        if (c != delim)
                return (0);
        port = i;

        /*
         * Check for CR-LF at the end of the command string.
         */
        if ((*s != '\r') || (*(s + 1) != '\n')) {
                DT(eprt4_no_crlf);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_eprt4:missing %s\n", "cr-lf");
                return (0);
        }
        s += 2;

        /*
         * Calculate new address parts for PORT command
         */
        if (nat->nat_dir == NAT_INBOUND)
                a1 = ntohl(nat->nat_odstaddr);
        else
                a1 = ntohl(ip->ip_src.s_addr);
        a2 = (a1 >> 16) & 0xff;
        a3 = (a1 >> 8) & 0xff;
        a4 = a1 & 0xff;
        a1 >>= 24;
        olen = s - f->ftps_rptr;
        /* DO NOT change this to snprintf! */
        /*
         * While we could force the use of | as a delimiter here, it makes
         * sense to preserve whatever character is being used by the systems
         * involved in the communication.
         */
        (void) snprintf(newbuf, sizeof(newbuf), "%s %c1%c%u.%u.%u.%u%c%u%c\r\n",
                       "EPRT", delim, delim, a1, a2, a3, a4, delim, port,
                        delim);

        nlen = strlen(newbuf);
        inc = nlen - olen;
        if ((inc + fin->fin_plen) > 65535) {
                DT2(eprt4_len, int, inc, int, fin->fin_plen);
                if (softf->ipf_p_ftp_debug & DEBUG_ERROR)
                        printf("ipf_p_ftp_eprt4:inc(%d) + ip->ip_len > 65535\n",
                                inc);
                return (0);
        }

        off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
#if !defined(_KERNEL)
        M_ADJ(m, inc);
#else
        if (inc < 0)
                M_ADJ(m, inc);
#endif
        /* the mbuf chain will be extended if necessary by m_copyback() */
        COPYBACK(m, off, nlen, newbuf);
        fin->fin_flx |= FI_DOCKSUM;

        if (inc != 0) {
                fin->fin_plen += inc;
                ip->ip_len = htons(fin->fin_plen);
                fin->fin_dlen += inc;
        }

        f->ftps_cmd = FTPXY_C_EPRT;
        return (ipf_p_ftp_addport(softf, fin, ip, nat, ftp, dlen, port, inc));
}


int
ipf_p_ftp_epsv(ipf_ftp_softc_t *softf, fr_info_t *fin, ip_t *ip, nat_t *nat,
        ftpinfo_t *ftp, int dlen)
{
        char newbuf[IPF_FTPBUFSZ];
        u_short ap = 0;
        ftpside_t *f;
        char *s;

        if ((softf->ipf_p_ftp_forcepasv != 0) &&
            (ftp->ftp_side[0].ftps_cmd != FTPXY_C_EPSV)) {
                DT1(epsv_cmd, int, ftp->ftp_side[0].ftps_cmd);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_epsv:ftps_cmd(%d) != FTPXY_C_EPSV\n",
                               ftp->ftp_side[0].ftps_cmd);
                return (0);
        }
        f = &ftp->ftp_side[1];

#define EPSV_REPLEN     33
        /*
         * Check for EPSV reply message.
         */
        if (dlen < IPF_MIN229LEN) {
                return (0);
        } else if (strncmp(f->ftps_rptr,
                         "229 Entering Extended Passive Mode", EPSV_REPLEN)) {
                return (0);
}

        /*
         * Skip the EPSV command + space
         */
        s = f->ftps_rptr + 33;
        while (*s && !ISDIGIT(*s))
                s++;

        /*
         * As per RFC 2428, there are no address components in the EPSV
         * response.  So we'll go straight to getting the port.
         */
        while (*s && ISDIGIT(*s)) {
                ap *= 10;
                ap += *s++ - '0';
        }

        if (*s == '|')
                s++;
        if (*s == ')')
                s++;
        if (*s == '\n')
                s--;
        /*
         * check for CR-LF at the end.
         */
        if ((*s != '\r') || (*(s + 1) != '\n')) {
                return (0);
        }
        s += 2;

        (void) snprintf(newbuf, sizeof(newbuf), "%s (|||%u|)\r\n",
                       "229 Entering Extended Passive Mode", ap);

        return (ipf_p_ftp_pasvreply(softf, fin, ip, nat, ftp, (u_int)ap,
                                   newbuf, s));
}

#ifdef USE_INET6
int
ipf_p_ftp_eprt6(ipf_ftp_softc_t *softf, fr_info_t *fin, ip_t *ip, nat_t *nat,
        ftpinfo_t *ftp, int dlen)
{
        int port, olen, nlen, inc, off, left, i;
        char newbuf[IPF_FTPBUFSZ];
        char *s, c;
        i6addr_t addr, *a6;
        tcphdr_t *tcp;
        ip6_t *ip6;
        char delim;
        u_short whole;
        u_short part;
        ftpside_t *f;
        u_short *t;
        int fwd;
        mb_t *m;
        u_32_t a;

        m = fin->fin_m;
        ip6 = (ip6_t *)ip;
        f = &ftp->ftp_side[0];
        s = f->ftps_rptr + 8;
        f = &ftp->ftp_side[0];
        delim = f->ftps_rptr[5];
        tcp = (tcphdr_t *)fin->fin_dp;
        off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;

        addr.i6[0] = 0;
        addr.i6[1] = 0;
        addr.i6[2] = 0;
        addr.i6[3] = 0;
        /*
         * Parse an IPv6 address.
         * Go forward until either :: or | is found. If :: is found,
         * reverse direction. Direction change is performed to ease
         * parsing an unknown number of 0s in the middle.
         */
        whole = 0;
        t = (u_short *)&addr;
        fwd = 1;
        for (part = 0; (c = *s) != '\0'; ) {
                if (c == delim) {
                        *t = htons((u_short)whole);
                        break;
                }
                if (c == ':') {
                        *t = part;
                        if (fwd) {
                                *t = htons((u_short)whole);
                                t++;
                        } else {
                                *t = htons((u_short)(whole >> 16));
                                t--;
                        }
                        whole = 0;
                        if (fwd == 1 && s[1] == ':') {
                                while (*s && *s != '|')
                                        s++;
                                if ((c = *s) != delim)
                                        break;
                                t = (u_short *)&addr.i6[3];
                                t++;
                                fwd = 0;
                        } else if (fwd == 0 && s[-1] == ':') {
                                break;
                        }
                } else {
                        if (c >= '0' && c <= '9') {
                                c -= '0';
                        } else if (c >= 'a' && c <= 'f') {
                                c -= 'a' + 10;
                        } else if (c >= 'A' && c <= 'F') {
                                c -= 'A' + 10;
                        }
                        if (fwd) {
                                whole <<= 8;
                                whole |= c;
                        } else {
                                whole >>= 8;
                                whole |= ((u_32_t)c) << 24;
                        }
                }
                if (fwd)
                        s++;
                else
                        s--;
        }
        if (c != ':' && c != delim)
                return (0);

        while (*s != '|')
                s++;
        s++;

        /*
         * Get the port number
         */
        i = 0;
        while (((c = *s++) != '\0') && ISDIGIT(c)) {
                i *= 10;
                i += c - '0';
        }
        if (i > 65535)
                return (0);
        if (c != delim)
                return (0);
        port = (u_short)(i & 0xffff);

        /*
         * Check for CR-LF at the end of the command string.
         */
        if ((*s != '\r') || (*(s + 1) != '\n')) {
                DT(eprt6_no_crlf);
                if (softf->ipf_p_ftp_debug & DEBUG_PARSE_ERR)
                        printf("ipf_p_ftp_eprt6:missing %s\n", "cr-lf");
                return (0);
        }
        s += 2;

        /*
         * Calculate new address parts for PORT command
         */
        a6 = (i6addr_t *)&ip6->ip6_src;
        olen = s - f->ftps_rptr;
        /* DO NOT change this to snprintf! */
        /*
         * While we could force the use of | as a delimiter here, it makes
         * sense to preserve whatever character is being used by the systems
         * involved in the communication.
         */
        s = newbuf;
        left = sizeof(newbuf);
        (void) snprintf(s, left, "EPRT %c2%c", delim, delim);
        s += strlen(s);
        a = ntohl(a6->i6[0]);
        snprintf(s, left, "%x:%x:", a >> 16, a & 0xffff);
        left -= strlen(s);
        s += strlen(s);
        a = ntohl(a6->i6[1]);
        snprintf(s, left, "%x:%x:", a >> 16, a & 0xffff);
        left -= strlen(s);
        s += strlen(s);
        a = ntohl(a6->i6[2]);
        snprintf(s,  left,"%x:%x:", a >> 16, a & 0xffff);
        left -= strlen(s);
        s += strlen(s);
        a = ntohl(a6->i6[3]);
        snprintf(s, left, "%x:%x", a >> 16, a & 0xffff);
        left -= strlen(s);
        s += strlen(s);
        snprintf(s, left, "|%d|\r\n", port);
        nlen = strlen(newbuf);
        inc = nlen - olen;
        if ((inc + fin->fin_plen) > 65535) {
                DT2(eprt6_len, int, inc, int, fin->fin_plen);
                if (softf->ipf_p_ftp_debug & DEBUG_ERROR)
                        printf("ipf_p_ftp_eprt6:inc(%d) + ip->ip_len > 65535\n",
                                inc);
                return (0);
        }

        off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
#if !defined(_KERNEL)
        M_ADJ(m, inc);
#else
        if (inc < 0)
                M_ADJ(m, inc);
#endif
        /* the mbuf chain will be extended if necessary by m_copyback() */
        COPYBACK(m, off, nlen, newbuf);
        fin->fin_flx |= FI_DOCKSUM;

        if (inc != 0) {
                fin->fin_plen += inc;
                ip6->ip6_plen = htons(fin->fin_plen - fin->fin_hlen);
                fin->fin_dlen += inc;
        }

        f->ftps_cmd = FTPXY_C_EPRT;
        return (ipf_p_ftp_addport(softf, fin, ip, nat, ftp, dlen, port, inc));
}
#endif