contrib/ipfilter/ip_ipsec_pxy.c

   1 /*
   2  * Simple ISAKMP transparent proxy for in-kernel use.  For use with the NAT
   3  * code.
   4  *
   5  * $Id: ip_ipsec_pxy.c,v 1.1.2.10 2002/01/13 04:58:29 darrenr Exp $
   6  *
   7  */
   8 #define IPF_IPSEC_PROXY
   9
  10
  11 int ippr_ipsec_init __P((void));
  12 int ippr_ipsec_new __P((fr_info_t *, ip_t *, ap_session_t *, nat_t *));
  13 void ippr_ipsec_del __P((ap_session_t *));
  14 int ippr_ipsec_out __P((fr_info_t *, ip_t *, ap_session_t *, nat_t *));
  15 int ippr_ipsec_match __P((fr_info_t *, ap_session_t *, nat_t *));
  16
  17 static  frentry_t       ipsecfr;
  18
  19
  20 static  char    ipsec_buffer[1500];
  21
  22 /*
  23  * RCMD application proxy initialization.
  24  */
  25 int ippr_ipsec_init()
  26 {
  27         bzero((char *)&ipsecfr, sizeof(ipsecfr));
  28         ipsecfr.fr_ref = 1;
  29         ipsecfr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
  30         return 0;
  31 }
  32
  33
  34 /*
  35  * Setup for a new IPSEC proxy.
  36  */
  37 int ippr_ipsec_new(fin, ip, aps, nat)
  38 fr_info_t *fin;
  39 ip_t *ip;
  40 ap_session_t *aps;
  41 nat_t *nat;
  42 {
  43         ipsec_pxy_t *ipsec;
  44         fr_info_t fi;
  45         ipnat_t *ipn;
  46         char *ptr;
  47         int p, off, dlen;
  48         mb_t *m;
  49
  50         bzero(ipsec_buffer, sizeof(ipsec_buffer));
  51         off = fin->fin_hlen + sizeof(udphdr_t);
  52 #ifdef  _KERNEL
  53 # if     SOLARIS
  54         m = fin->fin_qfm;
  55
  56         dlen = msgdsize(m) - off;
  57         if (dlen < 16)
  58                 return -1;
  59         copyout_mblk(m, off, MIN(sizeof(ipsec_buffer), dlen), ipsec_buffer);
  60 # else
  61         m = *(mb_t **)fin->fin_mp;
  62         dlen = mbufchainlen(m) - off;
  63         if (dlen < 16)
  64                 return -1;
  65         m_copydata(m, off, MIN(sizeof(ipsec_buffer), dlen), ipsec_buffer);
  66 # endif
  67 #else
  68         m = *(mb_t **)fin->fin_mp;
  69         dlen = ip->ip_len - off;
  70         ptr = (char *)m;
  71         ptr += off;
  72         bcopy(ptr, ipsec_buffer, MIN(sizeof(ipsec_buffer), dlen));
  73 #endif
  74
  75         /*
  76          * Because _new() gets called from nat_new(), ipf_nat is held with a
  77          * write lock so pass rw=1 to nat_outlookup().
  78          */
  79         if (nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_inip,
  80                           ip->ip_dst, 1) != NULL)
  81                 return -1;
  82
  83         aps->aps_psiz = sizeof(*ipsec);
  84         KMALLOCS(aps->aps_data, ipsec_pxy_t *, sizeof(*ipsec));
  85         if (aps->aps_data == NULL)
  86                 return -1;
  87
  88         ipsec = aps->aps_data;
  89         bzero((char *)ipsec, sizeof(*ipsec));
  90
  91         /*
  92          * Create NAT rule against which the tunnel/transport mapping is
  93          * created.  This is required because the current NAT rule does not
  94          * describe ESP but UDP instead.
  95          */
  96         ipn = &ipsec->ipsc_rule;
  97         ipn->in_ifp = fin->fin_ifp;
  98         ipn->in_apr = NULL;
  99         ipn->in_use = 1;
 100         ipn->in_hits = 1;
 101         ipn->in_nip = ntohl(nat->nat_outip.s_addr);
 102         ipn->in_ippip = 1;
 103         ipn->in_inip = nat->nat_inip.s_addr;
 104         ipn->in_inmsk = 0xffffffff;
 105         ipn->in_outip = nat->nat_outip.s_addr;
 106         ipn->in_outmsk = 0xffffffff;
 107         ipn->in_srcip = fin->fin_saddr;
 108         ipn->in_srcmsk = 0xffffffff;
 109         ipn->in_redir = NAT_MAP;
 110         bcopy(nat->nat_ptr->in_ifname, ipn->in_ifname, sizeof(ipn->in_ifname));
 111         ipn->in_p = IPPROTO_ESP;
 112
 113         bcopy((char *)fin, (char *)&fi, sizeof(fi));
 114         fi.fin_fi.fi_p = IPPROTO_ESP;
 115         fi.fin_fr = &ipsecfr;
 116         fi.fin_data[0] = 0;
 117         fi.fin_data[1] = 0;
 118         p = ip->ip_p;
 119         ip->ip_p = IPPROTO_ESP;
 120         fi.fin_fl &= ~FI_TCPUDP;
 121
 122         ptr = ipsec_buffer;
 123         bcopy(ptr, ipsec->ipsc_icookie, sizeof(ipsec_cookie_t));
 124         ptr += sizeof(ipsec_cookie_t);
 125         bcopy(ptr, ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t));
 126         /*
 127          * The responder cookie should only be non-zero if the initiator
 128          * cookie is non-zero.  Therefore, it is safe to assume(!) that the
 129          * cookies are both set after copying if the responder is non-zero.
 130          */
 131         if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0)
 132                 ipsec->ipsc_rckset = 1;
 133         else
 134                 nat->nat_age = 60;      /* 30 seconds */
 135
 136         ipsec->ipsc_nat = nat_new(&fi, ip, ipn, &ipsec->ipsc_nat, FI_IGNOREPKT,
 137                                    NAT_OUTBOUND);
 138         if (ipsec->ipsc_nat != NULL) {
 139                 fi.fin_data[0] = 0;
 140                 fi.fin_data[1] = 0;
 141                 ipsec->ipsc_state = fr_addstate(ip, &fi, &ipsec->ipsc_state,
 142                                                 FI_IGNOREPKT|FI_NORULE);
 143         }
 144         ip->ip_p = p;
 145         return 0;
 146 }
 147
 148
 149 /*
 150  * For outgoing IKE packets.  refresh timeouts for NAT & stat entries, if
 151  * we can.  If they have disappeared, recreate them.
 152  */
 153 int ippr_ipsec_out(fin, ip, aps, nat)
 154 fr_info_t *fin;
 155 ip_t *ip;
 156 ap_session_t *aps;
 157 nat_t *nat;
 158 {
 159         ipsec_pxy_t *ipsec;
 160         fr_info_t fi;
 161         int p;
 162
 163         bcopy((char *)fin, (char *)&fi, sizeof(fi));
 164         fi.fin_fi.fi_p = IPPROTO_ESP;
 165         fi.fin_fr = &ipsecfr;
 166         fi.fin_data[0] = 0;
 167         fi.fin_data[1] = 0;
 168         p = ip->ip_p;
 169         ip->ip_p = IPPROTO_ESP;
 170         fi.fin_fl &= ~FI_TCPUDP;
 171
 172         ipsec = aps->aps_data;
 173         if (ipsec != NULL) {
 174                 /*
 175                  * Update NAT timeout/create NAT if missing.
 176                  */
 177                 if (ipsec->ipsc_rckset == 0)
 178                         nat->nat_age = 60;      /* 30 seconds */
 179                 if (ipsec->ipsc_nat != NULL)
 180                         ipsec->ipsc_nat->nat_age = nat->nat_age;
 181                 else
 182                         ipsec->ipsc_nat = nat_new(&fi, ip, &ipsec->ipsc_rule,
 183                                                   &ipsec->ipsc_nat,
 184                                                   FI_IGNOREPKT, NAT_OUTBOUND);
 185
 186                 /*
 187                  * Update state timeout/create state if missing.
 188                  */
 189                 READ_ENTER(&ipf_state);
 190                 if (ipsec->ipsc_state != NULL) {
 191                         ipsec->ipsc_state->is_age = nat->nat_age;
 192                         RWLOCK_EXIT(&ipf_state);
 193                 } else {
 194                         RWLOCK_EXIT(&ipf_state);
 195                         fi.fin_data[0] = 0;
 196                         fi.fin_data[1] = 0;
 197                         ipsec->ipsc_state = fr_addstate(ip, &fi,
 198                                                         &ipsec->ipsc_state,
 199                                                         FI_IGNOREPKT|FI_NORULE);
 200                 }
 201         }
 202         ip->ip_p = p;
 203         return 0;
 204 }
 205
 206
 207 /*
 208  * This extends the NAT matching to be based on the cookies associated with
 209  * a session and found at the front of IKE packets.  The cookies are always
 210  * in the same order (not reversed depending on packet flow direction as with
 211  * UDP/TCP port numbers).
 212  */
 213 int ippr_ipsec_match(fin, aps, nat)
 214 fr_info_t *fin;
 215 ap_session_t *aps;
 216 nat_t *nat;
 217 {
 218         ipsec_pxy_t *ipsec;
 219         u_32_t cookies[4];
 220         mb_t *m;
 221         int off;
 222
 223         if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_fl & FI_FRAG))
 224                 return -1;
 225
 226         ipsec = aps->aps_data;
 227         off = fin->fin_hlen + sizeof(udphdr_t);
 228 #ifdef  _KERNEL
 229 # if     SOLARIS
 230         m = fin->fin_qfm;
 231
 232         copyout_mblk(m, off, sizeof(cookies), (char *)cookies);
 233 # else
 234         m = *(mb_t **)fin->fin_mp;
 235         m_copydata(m, off, sizeof(cookies), (char *)cookies);
 236 # endif
 237 #else
 238         m = *(mb_t **)fin->fin_mp;
 239         bcopy((char *)m + off, cookies, sizeof(cookies));
 240 #endif
 241
 242         if ((cookies[0] != ipsec->ipsc_icookie[0]) ||
 243             (cookies[1] != ipsec->ipsc_icookie[1]))
 244                 return -1;
 245
 246         if (ipsec->ipsc_rckset == 0) {
 247                 if ((cookies[2]|cookies[3]) == 0) {
 248                         nat->nat_age = 60;      /* 30 seconds */
 249                         return 0;
 250                 }
 251                 ipsec->ipsc_rckset = 1;
 252                 ipsec->ipsc_rcookie[0] = cookies[2];
 253                 ipsec->ipsc_rcookie[1] = cookies[3];
 254                 return 0;
 255         }
 256
 257         if ((cookies[2] != ipsec->ipsc_rcookie[0]) ||
 258             (cookies[3] != ipsec->ipsc_rcookie[1]))
 259                 return -1;
 260         return 0;
 261 }
 262
 263
 264 /*
 265  * clean up after ourselves.
 266  */
 267 void ippr_ipsec_del(aps)
 268 ap_session_t *aps;
 269 {
 270         ipsec_pxy_t *ipsec;
 271
 272         ipsec = aps->aps_data;
 273
 274         if (ipsec != NULL) {
 275                 /*
 276                  * Don't delete it from here, just schedule it to be
 277                  * deleted ASAP.
 278                  */
 279                 if (ipsec->ipsc_nat != NULL) {
 280                         ipsec->ipsc_nat->nat_age = 1;
 281                         ipsec->ipsc_nat->nat_ptr = NULL;
 282                 }
 283
 284                 READ_ENTER(&ipf_state);
 285                 if (ipsec->ipsc_state != NULL)
 286                         ipsec->ipsc_state->is_age = 1;
 287                 RWLOCK_EXIT(&ipf_state);
 288
 289                 ipsec->ipsc_state = NULL;
 290                 ipsec->ipsc_nat = NULL;
 291         }
 292 }