sys/contrib/ipfilter/netinet/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  * $FreeBSD: src/sys/contrib/ipfilter/netinet/ip_ipsec_pxy.c,v 1.1.1.1.2.1 2002/04/27 17:37:12 darrenr Exp $
   7  *
   8  */
   9 #define IPF_IPSEC_PROXY
  10
  11
  12 int ippr_ipsec_init __P((void));
  13 int ippr_ipsec_new __P((fr_info_t *, ip_t *, ap_session_t *, nat_t *));
  14 void ippr_ipsec_del __P((ap_session_t *));
  15 int ippr_ipsec_out __P((fr_info_t *, ip_t *, ap_session_t *, nat_t *));
  16 int ippr_ipsec_match __P((fr_info_t *, ap_session_t *, nat_t *));
  17
  18 static  frentry_t       ipsecfr;
  19
  20
  21 static  char    ipsec_buffer[1500];
  22
  23 /*
  24  * RCMD application proxy initialization.
  25  */
  26 int ippr_ipsec_init()
  27 {
  28         bzero((char *)&ipsecfr, sizeof(ipsecfr));
  29         ipsecfr.fr_ref = 1;
  30         ipsecfr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
  31         return 0;
  32 }
  33
  34
  35 /*
  36  * Setup for a new IPSEC proxy.
  37  */
  38 int ippr_ipsec_new(fin, ip, aps, nat)
  39 fr_info_t *fin;
  40 ip_t *ip;
  41 ap_session_t *aps;
  42 nat_t *nat;
  43 {
  44         ipsec_pxy_t *ipsec;
  45         fr_info_t fi;
  46         ipnat_t *ipn;
  47         char *ptr;
  48         int p, off, dlen;
  49         mb_t *m;
  50
  51         bzero(ipsec_buffer, sizeof(ipsec_buffer));
  52         off = fin->fin_hlen + sizeof(udphdr_t);
  53 #ifdef  _KERNEL
  54 # if     SOLARIS
  55         m = fin->fin_qfm;
  56
  57         dlen = msgdsize(m) - off;
  58         if (dlen < 16)
  59                 return -1;
  60         copyout_mblk(m, off, MIN(sizeof(ipsec_buffer), dlen), ipsec_buffer);
  61 # else
  62         m = *(mb_t **)fin->fin_mp;
  63         dlen = mbufchainlen(m) - off;
  64         if (dlen < 16)
  65                 return -1;
  66         m_copydata(m, off, MIN(sizeof(ipsec_buffer), dlen), ipsec_buffer);
  67 # endif
  68 #else
  69         m = *(mb_t **)fin->fin_mp;
  70         dlen = ip->ip_len - off;
  71         ptr = (char *)m;
  72         ptr += off;
  73         bcopy(ptr, ipsec_buffer, MIN(sizeof(ipsec_buffer), dlen));
  74 #endif
  75
  76         /*
  77          * Because _new() gets called from nat_new(), ipf_nat is held with a
  78          * write lock so pass rw=1 to nat_outlookup().
  79          */
  80         if (nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_inip,
  81                           ip->ip_dst, 1) != NULL)
  82                 return -1;
  83
  84         aps->aps_psiz = sizeof(*ipsec);
  85         KMALLOCS(aps->aps_data, ipsec_pxy_t *, sizeof(*ipsec));
  86         if (aps->aps_data == NULL)
  87                 return -1;
  88
  89         ipsec = aps->aps_data;
  90         bzero((char *)ipsec, sizeof(*ipsec));
  91
  92         /*
  93          * Create NAT rule against which the tunnel/transport mapping is
  94          * created.  This is required because the current NAT rule does not
  95          * describe ESP but UDP instead.
  96          */
  97         ipn = &ipsec->ipsc_rule;
  98         ipn->in_ifp = fin->fin_ifp;
  99         ipn->in_apr = NULL;
 100         ipn->in_use = 1;
 101         ipn->in_hits = 1;
 102         ipn->in_nip = ntohl(nat->nat_outip.s_addr);
 103         ipn->in_ippip = 1;
 104         ipn->in_inip = nat->nat_inip.s_addr;
 105         ipn->in_inmsk = 0xffffffff;
 106         ipn->in_outip = nat->nat_outip.s_addr;
 107         ipn->in_outmsk = 0xffffffff;
 108         ipn->in_srcip = fin->fin_saddr;
 109         ipn->in_srcmsk = 0xffffffff;
 110         ipn->in_redir = NAT_MAP;
 111         bcopy(nat->nat_ptr->in_ifname, ipn->in_ifname, sizeof(ipn->in_ifname));
 112         ipn->in_p = IPPROTO_ESP;
 113
 114         bcopy((char *)fin, (char *)&fi, sizeof(fi));
 115         fi.fin_fi.fi_p = IPPROTO_ESP;
 116         fi.fin_fr = &ipsecfr;
 117         fi.fin_data[0] = 0;
 118         fi.fin_data[1] = 0;
 119         p = ip->ip_p;
 120         ip->ip_p = IPPROTO_ESP;
 121         fi.fin_fl &= ~FI_TCPUDP;
 122
 123         ptr = ipsec_buffer;
 124         bcopy(ptr, ipsec->ipsc_icookie, sizeof(ipsec_cookie_t));
 125         ptr += sizeof(ipsec_cookie_t);
 126         bcopy(ptr, ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t));
 127         /*
 128          * The responder cookie should only be non-zero if the initiator
 129          * cookie is non-zero.  Therefore, it is safe to assume(!) that the
 130          * cookies are both set after copying if the responder is non-zero.
 131          */
 132         if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0)
 133                 ipsec->ipsc_rckset = 1;
 134         else
 135                 nat->nat_age = 60;      /* 30 seconds */
 136
 137         ipsec->ipsc_nat = nat_new(&fi, ip, ipn, &ipsec->ipsc_nat, FI_IGNOREPKT,
 138                                    NAT_OUTBOUND);
 139         if (ipsec->ipsc_nat != NULL) {
 140                 fi.fin_data[0] = 0;
 141                 fi.fin_data[1] = 0;
 142                 ipsec->ipsc_state = fr_addstate(ip, &fi, &ipsec->ipsc_state,
 143                                                 FI_IGNOREPKT|FI_NORULE);
 144         }
 145         ip->ip_p = p;
 146         return 0;
 147 }
 148
 149
 150 /*
 151  * For outgoing IKE packets.  refresh timeouts for NAT & stat entries, if
 152  * we can.  If they have disappeared, recreate them.
 153  */
 154 int ippr_ipsec_out(fin, ip, aps, nat)
 155 fr_info_t *fin;
 156 ip_t *ip;
 157 ap_session_t *aps;
 158 nat_t *nat;
 159 {
 160         ipsec_pxy_t *ipsec;
 161         fr_info_t fi;
 162         int p;
 163
 164         bcopy((char *)fin, (char *)&fi, sizeof(fi));
 165         fi.fin_fi.fi_p = IPPROTO_ESP;
 166         fi.fin_fr = &ipsecfr;
 167         fi.fin_data[0] = 0;
 168         fi.fin_data[1] = 0;
 169         p = ip->ip_p;
 170         ip->ip_p = IPPROTO_ESP;
 171         fi.fin_fl &= ~FI_TCPUDP;
 172
 173         ipsec = aps->aps_data;
 174         if (ipsec != NULL) {
 175                 /*
 176                  * Update NAT timeout/create NAT if missing.
 177                  */
 178                 if (ipsec->ipsc_rckset == 0)
 179                         nat->nat_age = 60;      /* 30 seconds */
 180                 if (ipsec->ipsc_nat != NULL)
 181                         ipsec->ipsc_nat->nat_age = nat->nat_age;
 182                 else
 183                         ipsec->ipsc_nat = nat_new(&fi, ip, &ipsec->ipsc_rule,
 184                                                   &ipsec->ipsc_nat,
 185                                                   FI_IGNOREPKT, NAT_OUTBOUND);
 186
 187                 /*
 188                  * Update state timeout/create state if missing.
 189                  */
 190                 READ_ENTER(&ipf_state);
 191                 if (ipsec->ipsc_state != NULL) {
 192                         ipsec->ipsc_state->is_age = nat->nat_age;
 193                         RWLOCK_EXIT(&ipf_state);
 194                 } else {
 195                         RWLOCK_EXIT(&ipf_state);
 196                         fi.fin_data[0] = 0;
 197                         fi.fin_data[1] = 0;
 198                         ipsec->ipsc_state = fr_addstate(ip, &fi,
 199                                                         &ipsec->ipsc_state,
 200                                                         FI_IGNOREPKT|FI_NORULE);
 201                 }
 202         }
 203         ip->ip_p = p;
 204         return 0;
 205 }
 206
 207
 208 /*
 209  * This extends the NAT matching to be based on the cookies associated with
 210  * a session and found at the front of IKE packets.  The cookies are always
 211  * in the same order (not reversed depending on packet flow direction as with
 212  * UDP/TCP port numbers).
 213  */
 214 int ippr_ipsec_match(fin, aps, nat)
 215 fr_info_t *fin;
 216 ap_session_t *aps;
 217 nat_t *nat;
 218 {
 219         ipsec_pxy_t *ipsec;
 220         u_32_t cookies[4];
 221         mb_t *m;
 222         int off;
 223
 224         if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_fl & FI_FRAG))
 225                 return -1;
 226
 227         ipsec = aps->aps_data;
 228         off = fin->fin_hlen + sizeof(udphdr_t);
 229 #ifdef  _KERNEL
 230 # if     SOLARIS
 231         m = fin->fin_qfm;
 232
 233         copyout_mblk(m, off, sizeof(cookies), (char *)cookies);
 234 # else
 235         m = *(mb_t **)fin->fin_mp;
 236         m_copydata(m, off, sizeof(cookies), (char *)cookies);
 237 # endif
 238 #else
 239         m = *(mb_t **)fin->fin_mp;
 240         bcopy((char *)m + off, cookies, sizeof(cookies));
 241 #endif
 242
 243         if ((cookies[0] != ipsec->ipsc_icookie[0]) ||
 244             (cookies[1] != ipsec->ipsc_icookie[1]))
 245                 return -1;
 246
 247         if (ipsec->ipsc_rckset == 0) {
 248                 if ((cookies[2]|cookies[3]) == 0) {
 249                         nat->nat_age = 60;      /* 30 seconds */
 250                         return 0;
 251                 }
 252                 ipsec->ipsc_rckset = 1;
 253                 ipsec->ipsc_rcookie[0] = cookies[2];
 254                 ipsec->ipsc_rcookie[1] = cookies[3];
 255                 return 0;
 256         }
 257
 258         if ((cookies[2] != ipsec->ipsc_rcookie[0]) ||
 259             (cookies[3] != ipsec->ipsc_rcookie[1]))
 260                 return -1;
 261         return 0;
 262 }
 263
 264
 265 /*
 266  * clean up after ourselves.
 267  */
 268 void ippr_ipsec_del(aps)
 269 ap_session_t *aps;
 270 {
 271         ipsec_pxy_t *ipsec;
 272
 273         ipsec = aps->aps_data;
 274
 275         if (ipsec != NULL) {
 276                 /*
 277                  * Don't delete it from here, just schedule it to be
 278                  * deleted ASAP.
 279                  */
 280                 if (ipsec->ipsc_nat != NULL) {
 281                         ipsec->ipsc_nat->nat_age = 1;
 282                         ipsec->ipsc_nat->nat_ptr = NULL;
 283                 }
 284
 285                 READ_ENTER(&ipf_state);
 286                 if (ipsec->ipsc_state != NULL)
 287                         ipsec->ipsc_state->is_age = 1;
 288                 RWLOCK_EXIT(&ipf_state);
 289
 290                 ipsec->ipsc_state = NULL;
 291                 ipsec->ipsc_nat = NULL;
 292         }
 293 }