/*
 * Copyright (C) 1998-2003 by Darren Reed
 *
 * See the IPFILTER.LICENCE file for details on licencing.
 *
 * $Id: ip_rcmd_pxy.c,v 1.41.2.4 2005/02/04 10:22:55 darrenr Exp $
 *
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * Simple RCMD transparent proxy for in-kernel use.  For use with the NAT
 * code.
 */

#define IPF_RCMD_PROXY

typedef struct ifs_rcmdpxy {
        frentry_t       rcmdfr;
        int             rcmd_proxy_init;
} ifs_rcmdpxy_t;

int ippr_rcmd_init __P((void **, ipf_stack_t *));
void ippr_rcmd_fini __P((void **, ipf_stack_t *));
int ippr_rcmd_new __P((fr_info_t *, ap_session_t *, nat_t *, void *));
int ippr_rcmd_out __P((fr_info_t *, ap_session_t *, nat_t *, void *));
int ippr_rcmd_in __P((fr_info_t *, ap_session_t *, nat_t *, void *));
u_short ipf_rcmd_atoi __P((char *));
int ippr_rcmd_portmsg __P((fr_info_t *, ap_session_t *, nat_t *, ifs_rcmdpxy_t *));

/*
 * RCMD application proxy initialization.
 */
/*ARGSUSED*/
int ippr_rcmd_init(private, ifs)
void **private;
ipf_stack_t *ifs;
{
        ifs_rcmdpxy_t *ifsrcmd;

        KMALLOC(ifsrcmd, ifs_rcmdpxy_t *);
        if (ifsrcmd == NULL)
                return -1;

        bzero((char *)&ifsrcmd->rcmdfr, sizeof(ifsrcmd->rcmdfr));
        ifsrcmd->rcmdfr.fr_ref = 1;
        ifsrcmd->rcmdfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
        MUTEX_INIT(&ifsrcmd->rcmdfr.fr_lock, "RCMD proxy rule lock");
        ifsrcmd->rcmd_proxy_init = 1;

        *private = (void *)ifsrcmd;

        return 0;
}


/*ARGSUSED*/
void ippr_rcmd_fini(private, ifs)
void **private;
ipf_stack_t *ifs;
{
        ifs_rcmdpxy_t *ifsrcmd = *((ifs_rcmdpxy_t **)private);

        if (ifsrcmd->rcmd_proxy_init == 1) {
                MUTEX_DESTROY(&ifsrcmd->rcmdfr.fr_lock);
                ifsrcmd->rcmd_proxy_init = 0;
        }

        KFREE(ifsrcmd);
        *private = NULL;
}


/*
 * Setup for a new RCMD proxy.
 */
/*ARGSUSED*/
int ippr_rcmd_new(fin, aps, nat, private)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
void *private;
{
        tcphdr_t *tcp = (tcphdr_t *)fin->fin_dp;

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

        aps->aps_psiz = sizeof(u_32_t);
        KMALLOCS(aps->aps_data, u_32_t *, sizeof(u_32_t));
        if (aps->aps_data == NULL) {
#ifdef IP_RCMD_PROXY_DEBUG
                printf("ippr_rcmd_new:KMALLOCS(%d) failed\n", sizeof(u_32_t));
#endif
                return -1;
        }
        *(u_32_t *)aps->aps_data = 0;
        aps->aps_sport = tcp->th_sport;
        aps->aps_dport = tcp->th_dport;
        return 0;
}


/*
 * ipf_rcmd_atoi - implement a simple version of atoi
 */
u_short ipf_rcmd_atoi(ptr)
char *ptr;
{
        register char *s = ptr, c;
        register u_short i = 0;

        while (((c = *s++) != '\0') && ISDIGIT(c)) {
                i *= 10;
                i += c - '0';
        }
        return i;
}


int ippr_rcmd_portmsg(fin, aps, nat, ifsrcmd)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
ifs_rcmdpxy_t *ifsrcmd;
{
        tcphdr_t *tcp, tcph, *tcp2 = &tcph;
        struct in_addr swip, swip2;
        int off, dlen, nflags;
        char portbuf[8], *s;
        fr_info_t fi;
        u_short sp;
        nat_t *nat2;
        ip_t *ip;
        mb_t *m;

        tcp = (tcphdr_t *)fin->fin_dp;

        if (tcp->th_flags & TH_SYN) {
                *(u_32_t *)aps->aps_data = htonl(ntohl(tcp->th_seq) + 1);
                return 0;
        }

        if ((*(u_32_t *)aps->aps_data != 0) &&
            (tcp->th_seq != *(u_32_t *)aps->aps_data))
                return 0;

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

#ifdef __sgi
        dlen = fin->fin_plen - off;
#else
        dlen = MSGDSIZE(m) - off;
#endif
        if (dlen <= 0)
                return 0;

        bzero(portbuf, sizeof(portbuf));
        COPYDATA(m, off, MIN(sizeof(portbuf), dlen), portbuf);

        portbuf[sizeof(portbuf) - 1] = '\0';
        s = portbuf;
        sp = ipf_rcmd_atoi(s);
        if (sp == 0) {
#ifdef IP_RCMD_PROXY_DEBUG
                printf("ippr_rcmd_portmsg:sp == 0 dlen %d [%s]\n",
                       dlen, portbuf);
#endif
                return 0;
        }

        /*
         * 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] = sp;
        fi.fin_data[1] = 0;
        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(*tcp);
                bzero((char *)tcp2, sizeof(*tcp2));
                tcp2->th_win = htons(8192);
                tcp2->th_sport = htons(sp);
                tcp2->th_dport = 0; /* XXX - don't specify remote port */
                TCP_OFF_A(tcp2, 5);
                tcp2->th_flags = TH_SYN;
                fi.fin_dp = (char *)tcp2;
                fi.fin_fr = &ifsrcmd->rcmdfr;
                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;
                nflags = NAT_SLAVE|IPN_TCP|SI_W_DPORT;

                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 {
                        fi.fin_fi.fi_saddr = nat->nat_oip.s_addr;
                        ip->ip_src = nat->nat_oip;
                        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, nat2->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;
        }
        return 0;
}


int ippr_rcmd_out(fin, aps, nat, private)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
void *private;
{
        if (nat->nat_dir == NAT_OUTBOUND)
                return ippr_rcmd_portmsg(fin, aps, nat, (ifs_rcmdpxy_t *)private);
        return 0;
}


int ippr_rcmd_in(fin, aps, nat, private)
fr_info_t *fin;
ap_session_t *aps;
nat_t *nat;
void *private;
{
        if (nat->nat_dir == NAT_INBOUND)
                return ippr_rcmd_portmsg(fin, aps, nat, (ifs_rcmdpxy_t *)private);
        return 0;
}