sys/dist/ipf/netinet/ip_rcmd_pxy.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (C) 1998-2003 by Darren Reed
   5  *
   6  * See the IPFILTER.LICENCE file for details on licencing.
   7  *
   8  * Id: ip_rcmd_pxy.c,v 1.41.2.10 2008/11/06 21:18:36 darrenr Exp
   9  *
  10  * Simple RCMD transparent proxy for in-kernel use.  For use with the NAT
  11  * code.
  12  */
  13
  14 #include <sys/cdefs.h>
  15 __KERNEL_RCSID(1, "$NetBSD$");
  16
  17 #define IPF_RCMD_PROXY
  18
  19
  20 int ippr_rcmd_init __P((void));
  21 void ippr_rcmd_fini __P((void));
  22 int ippr_rcmd_new __P((fr_info_t *, ap_session_t *, nat_t *));
  23 int ippr_rcmd_out __P((fr_info_t *, ap_session_t *, nat_t *));
  24 int ippr_rcmd_in __P((fr_info_t *, ap_session_t *, nat_t *));
  25 u_short ipf_rcmd_atoi __P((char *));
  26 int ippr_rcmd_portmsg __P((fr_info_t *, ap_session_t *, nat_t *));
  27
  28 static  frentry_t       rcmdfr;
  29
  30 int     rcmd_proxy_init = 0;
  31
  32
  33 /*
  34  * RCMD application proxy initialization.
  35  */
  36 int ippr_rcmd_init()
  37 {
  38         bzero((char *)&rcmdfr, sizeof(rcmdfr));
  39         rcmdfr.fr_ref = 1;
  40         rcmdfr.fr_flags = FR_INQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
  41         MUTEX_INIT(&rcmdfr.fr_lock, "RCMD proxy rule lock");
  42         rcmd_proxy_init = 1;
  43
  44         return 0;
  45 }
  46
  47
  48 void ippr_rcmd_fini()
  49 {
  50         if (rcmd_proxy_init == 1) {
  51                 MUTEX_DESTROY(&rcmdfr.fr_lock);
  52                 rcmd_proxy_init = 0;
  53         }
  54 }
  55
  56
  57 /*
  58  * Setup for a new RCMD proxy.
  59  */
  60 int ippr_rcmd_new(fin, aps, nat)
  61 fr_info_t *fin;
  62 ap_session_t *aps;
  63 nat_t *nat;
  64 {
  65         tcphdr_t *tcp = (tcphdr_t *)fin->fin_dp;
  66
  67         fin = fin;      /* LINT */
  68         nat = nat;      /* LINT */
  69
  70         aps->aps_psiz = sizeof(u_32_t);
  71         KMALLOCS(aps->aps_data, u_32_t *, sizeof(u_32_t));
  72         if (aps->aps_data == NULL) {
  73 #ifdef IP_RCMD_PROXY_DEBUG
  74                 printf("ippr_rcmd_new:KMALLOCS(%d) failed\n", sizeof(u_32_t));
  75 #endif
  76                 return -1;
  77         }
  78         *(u_32_t *)aps->aps_data = 0;
  79         aps->aps_sport = tcp->th_sport;
  80         aps->aps_dport = tcp->th_dport;
  81         return 0;
  82 }
  83
  84
  85 /*
  86  * ipf_rcmd_atoi - implement a simple version of atoi
  87  */
  88 u_short ipf_rcmd_atoi(ptr)
  89 char *ptr;
  90 {
  91         register char *s = ptr, c;
  92         register u_short i = 0;
  93
  94         while (((c = *s++) != '\0') && ISDIGIT(c)) {
  95                 i *= 10;
  96                 i += c - '0';
  97         }
  98         return i;
  99 }
 100
 101
 102 int ippr_rcmd_portmsg(fin, aps, nat)
 103 fr_info_t *fin;
 104 ap_session_t *aps;
 105 nat_t *nat;
 106 {
 107         tcphdr_t *tcp, tcph, *tcp2 = &tcph;
 108         struct in_addr swip, swip2;
 109         int off, dlen, nflags;
 110         char portbuf[8], *s;
 111         fr_info_t fi;
 112         u_short sp;
 113         nat_t *nat2;
 114         ip_t *ip;
 115         mb_t *m;
 116
 117         tcp = (tcphdr_t *)fin->fin_dp;
 118
 119         if (tcp->th_flags & TH_SYN) {
 120                 *(u_32_t *)aps->aps_data = htonl(ntohl(tcp->th_seq) + 1);
 121                 return 0;
 122         }
 123
 124         if ((*(u_32_t *)aps->aps_data != 0) &&
 125             (tcp->th_seq != *(u_32_t *)aps->aps_data))
 126                 return 0;
 127
 128         m = fin->fin_m;
 129         ip = fin->fin_ip;
 130         off = (char *)tcp - (char *)ip + (TCP_OFF(tcp) << 2) + fin->fin_ipoff;
 131
 132 #ifdef __sgi
 133         dlen = fin->fin_plen - off;
 134 #else
 135         dlen = MSGDSIZE(m) - off;
 136 #endif
 137         if (dlen <= 0)
 138                 return 0;
 139
 140         bzero(portbuf, sizeof(portbuf));
 141         COPYDATA(m, off, MIN(sizeof(portbuf), dlen), portbuf);
 142
 143         portbuf[sizeof(portbuf) - 1] = '\0';
 144         s = portbuf;
 145         sp = ipf_rcmd_atoi(s);
 146         if (sp == 0) {
 147 #ifdef IP_RCMD_PROXY_DEBUG
 148                 printf("ippr_rcmd_portmsg:sp == 0 dlen %d [%s]\n",
 149                        dlen, portbuf);
 150 #endif
 151                 return 0;
 152         }
 153
 154         /*
 155          * Add skeleton NAT entry for connection which will come back the
 156          * other way.
 157          */
 158         bcopy((char *)fin, (char *)&fi, sizeof(fi));
 159         fi.fin_flx |= FI_IGNORE;
 160         fi.fin_data[0] = sp;
 161         fi.fin_data[1] = 0;
 162         if (nat->nat_dir == NAT_OUTBOUND)
 163                 nat2 = nat_outlookup(&fi, NAT_SEARCH|IPN_TCP, nat->nat_p,
 164                                      nat->nat_inip, nat->nat_oip);
 165         else
 166                 nat2 = nat_inlookup(&fi, NAT_SEARCH|IPN_TCP, nat->nat_p,
 167                                     nat->nat_inip, nat->nat_oip);
 168         if (nat2 == NULL) {
 169                 int slen;
 170
 171                 slen = ip->ip_len;
 172                 ip->ip_len = fin->fin_hlen + sizeof(*tcp);
 173                 bzero((char *)tcp2, sizeof(*tcp2));
 174                 tcp2->th_win = htons(8192);
 175                 tcp2->th_sport = htons(sp);
 176                 tcp2->th_dport = 0; /* XXX - don't specify remote port */
 177                 TCP_OFF_A(tcp2, 5);
 178                 tcp2->th_flags = TH_SYN;
 179                 fi.fin_dp = (char *)tcp2;
 180                 fi.fin_fr = &rcmdfr;
 181                 fi.fin_dlen = sizeof(*tcp2);
 182                 fi.fin_plen = fi.fin_hlen + sizeof(*tcp2);
 183                 fi.fin_flx &= FI_LOWTTL|FI_FRAG|FI_TCPUDP|FI_OPTIONS|FI_IGNORE;
 184                 nflags = NAT_SLAVE|IPN_TCP|SI_W_DPORT;
 185
 186                 swip = ip->ip_src;
 187                 swip2 = ip->ip_dst;
 188
 189                 if (nat->nat_dir == NAT_OUTBOUND) {
 190                         fi.fin_fi.fi_saddr = nat->nat_inip.s_addr;
 191                         ip->ip_src = nat->nat_inip;
 192                 } else {
 193                         fi.fin_fi.fi_saddr = nat->nat_oip.s_addr;
 194                         ip->ip_src = nat->nat_oip;
 195                         nflags |= NAT_NOTRULEPORT;
 196                 }
 197
 198                 MUTEX_ENTER(&ipf_nat_new);
 199                 nat2 = nat_new(&fi, nat->nat_ptr, NULL, nflags, nat->nat_dir);
 200                 MUTEX_EXIT(&ipf_nat_new);
 201
 202                 if (nat2 != NULL) {
 203                         (void) nat_proto(&fi, nat2, IPN_TCP);
 204                         MUTEX_ENTER(&nat2->nat_lock);
 205                         nat_update(&fi, nat2);
 206                         MUTEX_EXIT(&nat2->nat_lock);
 207                         fi.fin_ifp = NULL;
 208                         if (nat->nat_dir == NAT_INBOUND) {
 209                                 fi.fin_fi.fi_daddr = nat->nat_inip.s_addr;
 210                                 ip->ip_dst = nat->nat_inip;
 211                         }
 212                         (void) fr_addstate(&fi, NULL, SI_W_DPORT);
 213                 }
 214                 ip->ip_len = slen;
 215                 ip->ip_src = swip;
 216                 ip->ip_dst = swip2;
 217         }
 218         return 0;
 219 }
 220
 221
 222 int ippr_rcmd_out(fin, aps, nat)
 223 fr_info_t *fin;
 224 ap_session_t *aps;
 225 nat_t *nat;
 226 {
 227         if (nat->nat_dir == NAT_OUTBOUND)
 228                 return ippr_rcmd_portmsg(fin, aps, nat);
 229         return 0;
 230 }
 231
 232
 233 int ippr_rcmd_in(fin, aps, nat)
 234 fr_info_t *fin;
 235 ap_session_t *aps;
 236 nat_t *nat;
 237 {
 238         if (nat->nat_dir == NAT_INBOUND)
 239                 return ippr_rcmd_portmsg(fin, aps, nat);
 240         return 0;
 241 }