/*
 * Copyright (C) 1997-2003 by Darren Reed
 *
 * See the IPFILTER.LICENCE file for details on licencing.
 *
 * $Id: ip_ftp_pxy.c,v 2.88.2.15 2005/03/19 19:38:10 darrenr Exp $
 *
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * Simple FTP transparent proxy for in-kernel use.  For use with the NAT
 * code.
*/

#define IPF_FTP_PROXY

#define IPF_MINPORTLEN  18
#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

/*
 * Values for FTP commands.  Numerics cover 0-999
 */
#define FTPXY_C_PASV    1000

typedef struct ifs_ftppxy {
        frentry_t               ftppxyfr;
        int                     ftp_proxy_init;
        int                     ippr_ftp_pasvonly;
        int                     ippr_ftp_insecure;
                                /* Do not require logins before transfers */
        int                     ippr_ftp_pasvrdr;
        int                     ippr_ftp_forcepasv;
                                /* PASV must be last command prior to 227 */
        /*
         * 1 - security
         * 2 - errors
         * 3 - error debugging
         * 4 - parsing errors
         * 5 - parsing info
         * 6 - parsing debug
         */
        int                     ippr_ftp_debug;
        ipftuneable_t           ftptune;
} ifs_ftppxy_t;

int ippr_ftp_client __P((fr_info_t *, ip_t *, nat_t *, ftpinfo_t *, int,
    ifs_ftppxy_t *));
int ippr_ftp_complete __P((char *, size_t));
int ippr_ftp_in __P((fr_info_t *, ap_session_t *, nat_t *, void *));
int ippr_ftp_init __P((void **, ipf_stack_t *));
void ippr_ftp_fini __P((void **, ipf_stack_t *));
int ippr_ftp_new __P((fr_info_t *, ap_session_t *, nat_t *, void *));
int ippr_ftp_out __P((fr_info_t *, ap_session_t *, nat_t *, void *));
int ippr_ftp_pasv __P((fr_info_t *, ip_t *, nat_t *, ftpinfo_t *, int,
    ifs_ftppxy_t *));
int ippr_ftp_epsv __P((fr_info_t *, ip_t *, nat_t *, ftpside_t *, int,
    ifs_ftppxy_t *));
int ippr_ftp_port __P((fr_info_t *, ip_t *, nat_t *, ftpside_t *, int,
    ifs_ftppxy_t *));
int ippr_ftp_process __P((fr_info_t *, nat_t *, ftpinfo_t *, int,
    ifs_ftppxy_t *));
int ippr_ftp_server __P((fr_info_t *, ip_t *, nat_t *, ftpinfo_t *, int,
    ifs_ftppxy_t *));
int ippr_ftp_valid __P((ftpinfo_t *, int, char *, size_t, ifs_ftppxy_t *));
int ippr_ftp_server_valid __P((ftpside_t *, char *, size_t, ifs_ftppxy_t *));
int ippr_ftp_client_valid __P((ftpside_t *, char *, size_t, ifs_ftppxy_t *));
u_short ippr_ftp_atoi __P((char **));
int ippr_ftp_pasvreply __P((fr_info_t *, ip_t *, nat_t *, ftpside_t *,
                            u_int, char *, char *, u_int, ifs_ftppxy_t *));

/*
 * Initialize local structures.
 */
int ippr_ftp_init(private, ifs)
void **private;
ipf_stack_t *ifs;
{
        ifs_ftppxy_t *ifsftp;

        KMALLOC(ifsftp, ifs_ftppxy_t *);
        if (ifsftp == NULL)
                return -1;

        bzero((char *)&ifsftp->ftppxyfr, sizeof(ifsftp->ftppxyfr));
        ifsftp->ftppxyfr.fr_ref = 1;
        ifsftp->ftppxyfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
        MUTEX_INIT(&ifsftp->ftppxyfr.fr_lock, "FTP Proxy Mutex");
        ifsftp->ftp_proxy_init = 1;
        ifsftp->ippr_ftp_pasvonly = 0;
        ifsftp->ippr_ftp_insecure = 0;
        ifsftp->ippr_ftp_pasvrdr = 0;
        ifsftp->ippr_ftp_forcepasv = 0;
#if defined(_KERNEL)
        ifsftp->ippr_ftp_debug = 0;
#else
        ifsftp->ippr_ftp_debug = 2;
#endif
        bzero((char *)&ifsftp->ftptune, sizeof(ifsftp->ftptune));
        ifsftp->ftptune.ipft_pint = (uint_t *)&ifsftp->ippr_ftp_debug;
        ifsftp->ftptune.ipft_name = "ippr_ftp_debug";
        ifsftp->ftptune.ipft_max = 10;
        ifsftp->ftptune.ipft_sz = sizeof(ifsftp->ippr_ftp_debug);
        ifsftp->ftptune.ipft_next = NULL;

        (void) fr_addipftune(&ifsftp->ftptune, ifs);

        *private = (void *)ifsftp;

        return 0;
}


void ippr_ftp_fini(private, ifs)
void **private;
ipf_stack_t *ifs;
{
        ifs_ftppxy_t *ifsftp = *((ifs_ftppxy_t **)private);

        (void) fr_delipftune(&ifsftp->ftptune, ifs);

        if (ifsftp->ftp_proxy_init == 1) {
                MUTEX_DESTROY(&ifsftp->ftppxyfr.fr_lock);
                ifsftp->ftp_proxy_init = 0;
        }

        KFREE(ifsftp);
        *private = NULL;
}


/*ARGSUSED*/
int ippr_ftp_new(fin, aps, nat, private)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
void *private;
{
        ftpinfo_t *ftp;
        ftpside_t *f;

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

        fin = fin;      /* LINT */
        nat = nat;      /* LINT */

        aps->aps_data = ftp;
        aps->aps_psiz = sizeof(ftpinfo_t);

        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;
}


int ippr_ftp_port(fin, ip, nat, f, dlen, ifsftp)
fr_info_t *fin;
ip_t *ip;
nat_t *nat;
ftpside_t *f;
int dlen;
ifs_ftppxy_t *ifsftp;
{
        tcphdr_t *tcp, tcph, *tcp2 = &tcph;
        char newbuf[IPF_FTPBUFSZ], *s;
        struct in_addr swip, swip2;
        u_int a1, a2, a3, a4;
        int inc, off, flags;
        u_short a5, a6, sp;
        size_t nlen, olen;
        fr_info_t fi;
        nat_t *nat2;
        mb_t *m;
        ipf_stack_t *ifs = fin->fin_ifs;

        m = fin->fin_m;
        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) {
                if (ifsftp->ippr_ftp_debug > 1)
                        printf("ippr_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 = ippr_ftp_atoi(&s);
        if (s == NULL) {
                if (ifsftp->ippr_ftp_debug > 1)
                        printf("ippr_ftp_port:ippr_ftp_atoi(%d) failed\n", 1);
                return 0;
        }
        a2 = ippr_ftp_atoi(&s);
        if (s == NULL) {
                if (ifsftp->ippr_ftp_debug > 1)
                        printf("ippr_ftp_port:ippr_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_inip.s_addr))) ||
            ((nat->nat_dir == NAT_INBOUND) &&
             (a1 != ntohl(nat->nat_oip.s_addr)))) {
                if (ifsftp->ippr_ftp_debug > 0)
                        printf("ippr_ftp_port:%s != nat->nat_inip\n", "a1");
                return APR_ERR(1);
        }

        a5 = ippr_ftp_atoi(&s);
        if (s == NULL) {
                if (ifsftp->ippr_ftp_debug > 1)
                        printf("ippr_ftp_port:ippr_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')) {
                s += 2;
                a6 = a5 & 0xff;
        } else {
                if (ifsftp->ippr_ftp_debug > 1)
                        printf("ippr_ftp_port:missing %s\n", "cr-lf");
                return 0;
        }

        a5 >>= 8;
        a5 &= 0xff;
        sp = a5 << 8 | a6;
        /*
         * Don't allow the PORT command to specify a port < 1024 due to
         * security crap.
         */
        if (sp < 1024) {
                if (ifsftp->ippr_ftp_debug > 0)
                        printf("ippr_ftp_port:sp(%d) < 1024\n", sp);
                return 0;
        }
        /*
         * Calculate new address parts for PORT command
         */
        if (nat->nat_dir == NAT_INBOUND)
                a1 = ntohl(nat->nat_oip.s_addr);
        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! */
#if defined(SNPRINTF) && defined(_KERNEL)
        (void) SNPRINTF(newbuf, sizeof(newbuf), "%s %u,%u,%u,%u,%u,%u\r\n",
                 "PORT", a1, a2, a3, a4, a5, a6);
#else
        (void) sprintf(newbuf, "%s %u,%u,%u,%u,%u,%u\r\n",
                       "PORT", a1, a2, a3, a4, a5, a6);
#endif

        nlen = strlen(newbuf);
        inc = nlen - olen;
        if ((inc + ip->ip_len) > 65535) {
                if (ifsftp->ippr_ftp_debug > 0)
                        printf("ippr_ftp_port:inc(%d) + ip->ip_len > 65535\n",
                               inc);
                return 0;
        }

#if !defined(_KERNEL)
        bcopy(newbuf, MTOD(m, char *) + off, nlen);
#else
# if defined(MENTAT)
        if (inc < 0)
                (void)adjmsg(m, inc);
# else /* defined(MENTAT) */
        /*
         * 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(MENTAT) */
#endif /* !defined(_KERNEL) */
        COPYBACK(m, off, nlen, newbuf);

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

        /*
         * 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;
        /*
         * Add skeleton NAT entry for connection which will come back the
         * other way.
         */
        if (nat->nat_dir == NAT_OUTBOUND)
                nat2 = nat_outlookup(&fi, NAT_SEARCH|IPN_TCP, nat->nat_p,
                                     nat->nat_inip, nat->nat_oip);
        else
                nat2 = nat_inlookup(&fi, NAT_SEARCH|IPN_TCP, nat->nat_p,
                                    nat->nat_inip, nat->nat_oip);
        if (nat2 == NULL) {
                int slen;

                slen = ip->ip_len;
                ip->ip_len = fin->fin_hlen + sizeof(*tcp2);
                bzero((char *)tcp2, sizeof(*tcp2));
                tcp2->th_win = htons(8192);
                tcp2->th_sport = htons(sp);
                TCP_OFF_A(tcp2, 5);
                tcp2->th_flags = TH_SYN;
                tcp2->th_dport = 0; /* XXX - don't specify remote port */
                fi.fin_data[1] = 0;
                fi.fin_dlen = sizeof(*tcp2);
                fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
                fi.fin_dp = (char *)tcp2;
                fi.fin_fr = &ifsftp->ftppxyfr;
                fi.fin_out = nat->nat_dir;
                fi.fin_flx &= FI_LOWTTL|FI_FRAG|FI_TCPUDP|FI_OPTIONS|FI_IGNORE;
                swip = ip->ip_src;
                swip2 = ip->ip_dst;
                if (nat->nat_dir == NAT_OUTBOUND) {
                        fi.fin_fi.fi_saddr = nat->nat_inip.s_addr;
                        ip->ip_src = nat->nat_inip;
                } else if (nat->nat_dir == NAT_INBOUND) {
                        fi.fin_fi.fi_saddr = nat->nat_oip.s_addr;
                        ip->ip_src = nat->nat_oip;
                }

                flags = NAT_SLAVE|IPN_TCP|SI_W_DPORT;
                if (nat->nat_dir == NAT_INBOUND)
                        flags |= NAT_NOTRULEPORT;
                nat2 = nat_new(&fi, nat->nat_ptr, NULL, flags, nat->nat_dir);

                if (nat2 != NULL) {
                        (void) nat_proto(&fi, nat2, IPN_TCP);
                        nat_update(&fi, nat2, nat->nat_ptr);
                        fi.fin_ifp = NULL;
                        if (nat->nat_dir == NAT_INBOUND) {
                                fi.fin_fi.fi_daddr = nat->nat_inip.s_addr;
                                ip->ip_dst = nat->nat_inip;
                        }
                        (void) fr_addstate(&fi, &nat2->nat_state, SI_W_DPORT);
                }
                ip->ip_len = slen;
                ip->ip_src = swip;
                ip->ip_dst = swip2;
        } else {
                ipstate_t *is;

                nat_update(&fi, nat2, nat->nat_ptr);
                READ_ENTER(&ifs->ifs_ipf_state);
                is = nat2->nat_state;
                if (is != NULL) {
                        MUTEX_ENTER(&is->is_lock);
                        (void)fr_tcp_age(&is->is_sti, &fi, ifs->ifs_ips_tqtqb,
                                         is->is_flags);
                        MUTEX_EXIT(&is->is_lock);
                }
                RWLOCK_EXIT(&ifs->ifs_ipf_state);
        }
        return APR_INC(inc);
}


int ippr_ftp_client(fin, ip, nat, ftp, dlen, ifsftp)
fr_info_t *fin;
nat_t *nat;
ftpinfo_t *ftp;
ip_t *ip;
int dlen;
ifs_ftppxy_t *ifsftp;
{
        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;
        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) &&
                 !ifsftp->ippr_ftp_pasvonly &&
                 !strncmp(cmd, "PORT ", 5)) {
                inc = ippr_ftp_port(fin, ip, nat, f, dlen, ifsftp);
        } else if (ifsftp->ippr_ftp_insecure && !ifsftp->ippr_ftp_pasvonly &&
                   !strncmp(cmd, "PORT ", 5)) {
                inc = ippr_ftp_port(fin, ip, nat, f, dlen, ifsftp);
        }

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


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

        if (ifsftp->ippr_ftp_forcepasv != 0 &&
            ftp->ftp_side[0].ftps_cmds != FTPXY_C_PASV) {
                if (ifsftp->ippr_ftp_debug > 0)
                        printf("ippr_ftp_pasv:ftps_cmds(%d) != FTPXY_C_PASV\n",
                               ftp->ftp_side[0].ftps_cmds);
                return 0;
        }

        f = &ftp->ftp_side[1];

#define PASV_REPLEN     24
        /*
         * Check for PASV reply message.
         */
        if (dlen < IPF_MIN227LEN) {
                if (ifsftp->ippr_ftp_debug > 1)
                        printf("ippr_ftp_pasv:dlen(%d) < IPF_MIN227LEN\n",
                               dlen);
                return 0;
        } else if (strncmp(f->ftps_rptr,
                           "227 Entering Passive Mod", PASV_REPLEN)) {
                if (ifsftp->ippr_ftp_debug > 0)
                        printf("ippr_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 = ippr_ftp_atoi(&s);
        if (s == NULL) {
                if (ifsftp->ippr_ftp_debug > 1)
                        printf("ippr_ftp_pasv:ippr_ftp_atoi(%d) failed\n", 1);
                return 0;
        }
        a2 = ippr_ftp_atoi(&s);
        if (s == NULL) {
                if (ifsftp->ippr_ftp_debug > 1)
                        printf("ippr_ftp_pasv:ippr_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_inip.s_addr))) ||
            ((nat->nat_dir == NAT_OUTBOUND) &&
             (a1 != ntohl(nat->nat_oip.s_addr)))) {
                if (ifsftp->ippr_ftp_debug > 0)
                        printf("ippr_ftp_pasv:%s != nat->nat_oip\n", "a1");
                return 0;
        }

        a5 = ippr_ftp_atoi(&s);
        if (s == NULL) {
                if (ifsftp->ippr_ftp_debug > 1)
                        printf("ippr_ftp_pasv:ippr_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')) {
                s += 2;
        } else {
                if (ifsftp->ippr_ftp_debug > 1)
                        printf("ippr_ftp_pasv:missing %s", "cr-lf\n");
                return 0;
        }

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

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

#if defined(SNPRINTF) && defined(_KERNEL)
        (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]);
#else
        (void) sprintf(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]);
#endif
        return ippr_ftp_pasvreply(fin, ip, nat, f, (a5 << 8 | a6),
                                  newbuf, s, data_ip, ifsftp);
}

int ippr_ftp_pasvreply(fin, ip, nat, f, port, newmsg, s, data_ip, ifsftp)
fr_info_t *fin;
ip_t *ip;
nat_t *nat;
ftpside_t *f;
u_int port;
char *newmsg;
char *s;
u_int data_ip;
ifs_ftppxy_t *ifsftp;
{
        int inc, off, nflags, sflags;
        tcphdr_t *tcp, tcph, *tcp2;
        struct in_addr swip, swip2;
        struct in_addr data_addr;
        size_t nlen, olen;
        fr_info_t fi;
        nat_t *nat2;
        mb_t *m;
        ipf_stack_t *ifs = fin->fin_ifs;

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

        data_addr.s_addr = data_ip;
        tcp2 = &tcph;
        inc = 0;


        olen = s - f->ftps_rptr;
        nlen = strlen(newmsg);
        inc = nlen - olen;
        if ((inc + ip->ip_len) > 65535) {
                if (ifsftp->ippr_ftp_debug > 0)
                        printf("ippr_ftp_pasv:inc(%d) + ip->ip_len > 65535\n",
                               inc);
                return 0;
        }

#if !defined(_KERNEL)
        bcopy(newmsg, MTOD(m, char *) + off, nlen);
#else
# if defined(MENTAT)
        if (inc < 0)
                (void)adjmsg(m, inc);
# else /* defined(MENTAT) */
        /*
         * 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(MENTAT) */
#endif /* !defined(_KERNEL) */
        COPYBACK(m, off, nlen, newmsg);

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

        /*
         * Add skeleton NAT entry for connection which will come back the
         * other way.
         */
        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;
        if (ifsftp->ippr_ftp_pasvrdr && f->ftps_ifp)
                nflags |= SI_W_DPORT;
        if (nat->nat_dir == NAT_OUTBOUND)
                nat2 = nat_outlookup(&fi, nflags|NAT_SEARCH,
                                     nat->nat_p, nat->nat_inip, nat->nat_oip);
        else
                nat2 = nat_inlookup(&fi, nflags|NAT_SEARCH,
                                    nat->nat_p, nat->nat_inip, nat->nat_oip);
        if (nat2 == NULL) {
                int slen;

                slen = ip->ip_len;
                ip->ip_len = fin->fin_hlen + sizeof(*tcp2);
                bzero((char *)tcp2, sizeof(*tcp2));
                tcp2->th_win = htons(8192);
                tcp2->th_sport = 0;             /* XXX - fake it for nat_new */
                TCP_OFF_A(tcp2, 5);
                tcp2->th_flags = TH_SYN;
                fi.fin_data[1] = port;
                fi.fin_dlen = sizeof(*tcp2);
                tcp2->th_dport = htons(port);
                fi.fin_data[0] = 0;
                fi.fin_dp = (char *)tcp2;
                fi.fin_plen = fi.fin_hlen + sizeof(*tcp);
                fi.fin_fr = &ifsftp->ftppxyfr;
                fi.fin_out = nat->nat_dir;
                fi.fin_flx &= FI_LOWTTL|FI_FRAG|FI_TCPUDP|FI_OPTIONS|FI_IGNORE;
                swip = ip->ip_src;
                swip2 = ip->ip_dst;
                if (nat->nat_dir == NAT_OUTBOUND) {
                        fi.fin_fi.fi_daddr = data_addr.s_addr;
                        fi.fin_fi.fi_saddr = nat->nat_inip.s_addr;
                        ip->ip_dst = data_addr;
                        ip->ip_src = nat->nat_inip;
                } else if (nat->nat_dir == NAT_INBOUND) {
                        fi.fin_fi.fi_saddr = nat->nat_oip.s_addr;
                        fi.fin_fi.fi_daddr = nat->nat_outip.s_addr;
                        ip->ip_src = nat->nat_oip;
                        ip->ip_dst = nat->nat_outip;
                }

                sflags = nflags;
                nflags |= NAT_SLAVE;
                if (nat->nat_dir == NAT_INBOUND)
                        nflags |= NAT_NOTRULEPORT;
                nat2 = nat_new(&fi, nat->nat_ptr, NULL, nflags, nat->nat_dir);
                if (nat2 != NULL) {
                        (void) nat_proto(&fi, nat2, IPN_TCP);
                        nat_update(&fi, nat2, nat->nat_ptr);
                        fi.fin_ifp = NULL;
                        if (nat->nat_dir == NAT_INBOUND) {
                                fi.fin_fi.fi_daddr = nat->nat_inip.s_addr;
                                ip->ip_dst = nat->nat_inip;
                        }
                        (void) fr_addstate(&fi, &nat2->nat_state, sflags);
                }

                ip->ip_len = slen;
                ip->ip_src = swip;
                ip->ip_dst = swip2;
        } else {
                ipstate_t *is;

                nat_update(&fi, nat2, nat->nat_ptr);
                READ_ENTER(&ifs->ifs_ipf_state);
                is = nat2->nat_state;
                if (is != NULL) {
                        MUTEX_ENTER(&is->is_lock);
                        (void) fr_tcp_age(&is->is_sti, &fi, ifs->ifs_ips_tqtqb,
                                          is->is_flags);
                        MUTEX_EXIT(&is->is_lock);
                }
                RWLOCK_EXIT(&ifs->ifs_ipf_state);
        }
        return inc;
}


int ippr_ftp_server(fin, ip, nat, ftp, dlen, ifsftp)
fr_info_t *fin;
ip_t *ip;
nat_t *nat;
ftpinfo_t *ftp;
int dlen;
ifs_ftppxy_t *ifsftp;
{
        char *rptr, *wptr;
        ftpside_t *f;
        int inc;

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

        if (*rptr == ' ')
                goto server_cmd_ok;
        if (!ISDIGIT(*rptr) || !ISDIGIT(*(rptr + 1)) || !ISDIGIT(*(rptr + 2)))
                return 0;
        if (ftp->ftp_passok == FTPXY_GO) {
                if (!strncmp(rptr, "227 ", 4))
                        inc = ippr_ftp_pasv(fin, ip, nat, ftp, dlen, ifsftp);
                else if (!strncmp(rptr, "229 ", 4))
                        inc = ippr_ftp_epsv(fin, ip, nat, f, dlen, ifsftp);
        } else if (ifsftp->ippr_ftp_insecure && !strncmp(rptr, "227 ", 4)) {
                inc = ippr_ftp_pasv(fin, ip, nat, ftp, dlen, ifsftp);
        } else if (ifsftp->ippr_ftp_insecure && !strncmp(rptr, "229 ", 4)) {
                inc = ippr_ftp_epsv(fin, ip, nat, f, dlen, ifsftp);
        } 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;
                        }
                }
        }
server_cmd_ok:
        ftp->ftp_incok = 0;

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


/*
 * Look to see if the buffer starts with something which we recognise as
 * being the correct syntax for the FTP protocol.
 */
int ippr_ftp_client_valid(ftps, buf, len, ifsftp)
ftpside_t *ftps;
char *buf;
size_t len;
ifs_ftppxy_t *ifsftp;
{
        register char *s, c, pc;
        register size_t i = len;
        char cmd[5];

        s = buf;

        if (ftps->ftps_junk == 1)
                return 1;

        if (i < 5) {
                if (ifsftp->ippr_ftp_debug > 3)
                        printf("ippr_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:
                if (ifsftp->ippr_ftp_debug > 3)
                        printf("%s:bad:junk %d len %d/%d c 0x%x buf [%*s]\n",
                               "ippr_ftp_client_valid",
                               ftps->ftps_junk, (int)len, (int)i, c,
                               (int)len, buf);
                return 1;
        }

        for (; i; i--) {
                pc = c;
                c = *s++;
                if ((pc == '\r') && (c == '\n')) {
                        cmd[4] = '\0';
                        if (!strcmp(cmd, "PASV"))
                                ftps->ftps_cmds = FTPXY_C_PASV;
                        else
                                ftps->ftps_cmds = 0;
                        return 0;
                }
        }
#if !defined(_KERNEL)
        printf("ippr_ftp_client_valid:junk after cmd[%*.*s]\n",
               (int)len, (int)len, buf);
#endif
        return 2;
}


int ippr_ftp_server_valid(ftps, buf, len, ifsftp)
ftpside_t *ftps;
char *buf;
size_t len;
ifs_ftppxy_t *ifsftp;
{
        register char *s, c, pc;
        register size_t i = len;
        int cmd;

        s = buf;
        cmd = 0;

        if (ftps->ftps_junk == 1)
                return 1;

        if (i < 5) {
                if (ifsftp->ippr_ftp_debug > 3)
                        printf("ippr_ftp_servert_valid:i(%d) < 5\n", (int)i);
                return 2;
        }

        c = *s++;
        i--;
        if (c == ' ')
                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;
                        } else
                                goto bad_server_command;
                } else
                        goto bad_server_command;
        } else {
bad_server_command:
                if (ifsftp->ippr_ftp_debug > 3)
                        printf("%s:bad:junk %d len %d/%d c 0x%x buf [%*s]\n",
                               "ippr_ftp_server_valid",
                               ftps->ftps_junk, (int)len, (int)i,
                               c, (int)len, buf);
                return 1;
        }
search_eol:
        for (; i; i--) {
                pc = c;
                c = *s++;
                if ((pc == '\r') && (c == '\n')) {
                        ftps->ftps_cmds = cmd;
                        return 0;
                }
        }
        if (ifsftp->ippr_ftp_debug > 3)
                printf("ippr_ftp_server_valid:junk after cmd[%*s]\n",
                       (int)len, buf);
        return 2;
}


int ippr_ftp_valid(ftp, side, buf, len, ifsftp)
ftpinfo_t *ftp;
int side;
char *buf;
size_t len;
ifs_ftppxy_t *ifsftp;
{
        ftpside_t *ftps;
        int ret;

        ftps = &ftp->ftp_side[side];

        if (side == 0)
                ret = ippr_ftp_client_valid(ftps, buf, len, ifsftp);
        else
                ret = ippr_ftp_server_valid(ftps, buf, len, ifsftp);
        return ret;
}


/*
 * 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 ippr_ftp_process(fin, nat, ftp, rv, ifsftp)
fr_info_t *fin;
nat_t *nat;
ftpinfo_t *ftp;
int rv;
ifs_ftppxy_t *ifsftp;
{
        int mlen, len, off, inc, i, sel, sel2, ok, ackoff, seqoff;
        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);

#ifdef __sgi
        mlen = fin->fin_plen - off;
#else
        mlen = MSGDSIZE(m) - off;
#endif
        if (ifsftp->ippr_ftp_debug > 4)
                printf("ippr_ftp_process: mlen %d\n", mlen);

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

        sel = aps->aps_sel[1 - rv];
        sel2 = aps->aps_sel[rv];
        if (rv == 0) {
                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 (ifsftp->ippr_ftp_debug > 2)
                        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 (ifsftp->ippr_ftp_debug > 2)
                        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 (ifsftp->ippr_ftp_debug > 2) {
                printf("%s: %x seq %x/%d ack %x/%d len %d/%d off %d\n",
                       rv ? "IN" : "OUT", tcp->th_flags, 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 (ifsftp->ippr_ftp_debug > 2) {
                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)
                                ok = 1;
                        else if (t->ftps_seq[0] == thack + ackoff)
                                ok = 1;
                        else if (t->ftps_seq[1] + ackoff == thack) {
                                t->ftps_seq[0] = thack - ackoff;
                                ok = 1;
                        } else if (t->ftps_seq[1] == thack + ackoff) {
                                t->ftps_seq[0] = thack - ackoff;
                                ok = 1;
                        }
                }
        }

        if (ifsftp->ippr_ftp_debug > 2) {
                if (!ok)
                        printf("%s ok\n", "not");
        }

        if (!mlen) {
                if (t->ftps_seq[0] + ackoff != thack) {
                        if (ifsftp->ippr_ftp_debug > 1) {
                                printf("%s:seq[0](%x) + (%x) != (%x)\n",
                                       "ippr_ftp_process", t->ftps_seq[0],
                                       ackoff, thack);
                        }
                        return APR_ERR(1);
                }

                if (ifsftp->ippr_ftp_debug > 2) {
                        printf("ippr_ftp_process:f:seq[0] %x seq[1] %x\n",
                                f->ftps_seq[0], f->ftps_seq[1]);
                }

                if (tcp->th_flags & 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 {
                                if (ifsftp->ippr_ftp_debug > 1) {
                                        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) {
                inc = thseq - f->ftps_seq[0];
                if (ifsftp->ippr_ftp_debug > 1) {
                        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));
                COPYDATA(m, off, len, wptr);
                mlen -= len;
                off += len;
                wptr += len;

                if (ifsftp->ippr_ftp_debug > 3)
                        printf("%s:len %d/%d off %d wptr %lx junk %d [%*s]\n",
                               "ippr_ftp_process",
                               len, mlen, off, (u_long)wptr, f->ftps_junk,
                               len, rptr);

                f->ftps_wptr = wptr;
                if (f->ftps_junk != 0) {
                        i = f->ftps_junk;
                        f->ftps_junk = ippr_ftp_valid(ftp, rv, rptr,
                                                      wptr - rptr, ifsftp);

                        if (ifsftp->ippr_ftp_debug > 5)
                                printf("%s:junk %d -> %d\n",
                                       "ippr_ftp_process", i, f->ftps_junk);

                        if (f->ftps_junk != 0) {
                                if (wptr - rptr == sizeof(f->ftps_buf)) {
                                        if (ifsftp->ippr_ftp_debug > 4)
                                                printf("%s:full buffer\n",
                                                       "ippr_ftp_process");
                                        f->ftps_rptr = f->ftps_buf;
                                        f->ftps_wptr = f->ftps_buf;
                                        rptr = f->ftps_rptr;
                                        wptr = f->ftps_wptr;
                                        /*
                                         * Because we throw away data here that
                                         * we would otherwise parse, set the
                                         * junk flag to indicate just ignore
                                         * any data upto the next CRLF.
                                         */
                                        f->ftps_junk = 1;
                                        continue;
                                }
                        }
                }

                while ((f->ftps_junk == 0) && (wptr > rptr)) {
                        len = wptr - rptr;
                        f->ftps_junk = ippr_ftp_valid(ftp, rv, rptr, len, ifsftp);

                        if (ifsftp->ippr_ftp_debug > 3) {
                                printf("%s=%d len %d rv %d ptr %lx/%lx ",
                                       "ippr_ftp_valid",
                                       f->ftps_junk, len, rv, (u_long)rptr,
                                       (u_long)wptr);
                                printf("buf [%*s]\n", len, rptr);
                        }

                        if (f->ftps_junk == 0) {
                                f->ftps_rptr = rptr;
                                if (rv)
                                        inc += ippr_ftp_server(fin, ip, nat,
                                                               ftp, len, ifsftp);
                                else
                                        inc += ippr_ftp_client(fin, ip, nat,
                                                               ftp, len, ifsftp);
                                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 == 1)) {
                        /* f->ftps_seq[1] += inc; */

                        if (ifsftp->ippr_ftp_debug > 1)
                                printf("%s:cmds == 0 junk == 1\n",
                                       "ippr_ftp_process");
                        return APR_ERR(2);
                }

                if ((f->ftps_junk != 0) && (rptr < wptr)) {
                        for (s = rptr; s < wptr; s++) {
                                if ((*s == '\r') && (s + 1 < wptr) &&
                                    (*(s + 1) == '\n')) {
                                        rptr = s + 2;
                                        f->ftps_junk = 0;
                                        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, len);
                                wptr -= rptr - f->ftps_buf;
                                rptr = f->ftps_buf;
                        }
                }
                f->ftps_rptr = rptr;
                f->ftps_wptr = wptr;
        }

        /* f->ftps_seq[1] += inc; */
        if (tcp->th_flags & TH_FIN)
                f->ftps_seq[1]++;
        if (ifsftp->ippr_ftp_debug > 3) {
#ifdef __sgi
                mlen = fin->fin_plen;
#else
                mlen = MSGDSIZE(m);
#endif
                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 ippr_ftp_out(fin, aps, nat, private)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
void *private;
{
        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 ippr_ftp_process(fin, nat, ftp, rev, (ifs_ftppxy_t *)private);
}


int ippr_ftp_in(fin, aps, nat, private)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
void *private;
{
        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 ippr_ftp_process(fin, nat, ftp, 1 - rev, (ifs_ftppxy_t *)private);
}


/*
 * ippr_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 ippr_ftp_atoi(ptr)
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 ippr_ftp_epsv(fin, ip, nat, f, dlen, ifsftp)
fr_info_t *fin;
ip_t *ip;
nat_t *nat;
ftpside_t *f;
int dlen;
ifs_ftppxy_t *ifsftp;
{
        char newbuf[IPF_FTPBUFSZ];
        char *s;
        u_short ap = 0;

#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 addres 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)
                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')) {
                s += 2;
        } else
                return 0;

#if defined(SNPRINTF) && defined(_KERNEL)
        (void) SNPRINTF(newbuf, sizeof(newbuf), "%s (|||%u|)\r\n",
                 "229 Entering Extended Passive Mode", ap);
#else
        (void) sprintf(newbuf, "%s (|||%u|)\r\n",
                       "229 Entering Extended Passive Mode", ap);
#endif

        return ippr_ftp_pasvreply(fin, ip, nat, f, (u_int)ap, newbuf, s,
                                  ip->ip_src.s_addr, ifsftp);
}