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  * $DragonFly: src/sys/contrib/ipfilter/netinet/ip_ipsec_pxy.c,v 1.3 2003/08/27 11:02:14 rob Exp $
   8  *
   9  */
  10 #define IPF_IPSEC_PROXY
  11
  12
  13 int ippr_ipsec_init (void);
  14 int ippr_ipsec_new (fr_info_t *, ip_t *, ap_session_t *, nat_t *);
  15 void ippr_ipsec_del (ap_session_t *);
  16 int ippr_ipsec_out (fr_info_t *, ip_t *, ap_session_t *, nat_t *);
  17 int ippr_ipsec_match (fr_info_t *, ap_session_t *, nat_t *);
  18
  19 static  frentry_t       ipsecfr;
  20
  21
  22 static  char    ipsec_buffer[1500];
  23
  24 /*
  25  * RCMD application proxy initialization.
  26  */
  27 int ippr_ipsec_init()
  28 {
  29         bzero((char *)&ipsecfr, sizeof(ipsecfr));
  30         ipsecfr.fr_ref = 1;
  31         ipsecfr.fr_flags = FR_OUTQUE|FR_PASS|FR_QUICK|FR_KEEPSTATE;
  32         return 0;
  33 }
  34
  35
  36 /*
  37  * Setup for a new IPSEC proxy.
  38  */
  39 int ippr_ipsec_new(fin, ip, aps, nat)
  40 fr_info_t *fin;
  41 ip_t *ip;
  42 ap_session_t *aps;
  43 nat_t *nat;
  44 {
  45         ipsec_pxy_t *ipsec;
  46         fr_info_t fi;
  47         ipnat_t *ipn;
  48         char *ptr;
  49         int p, off, dlen;
  50         mb_t *m;
  51
  52         bzero(ipsec_buffer, sizeof(ipsec_buffer));
  53         off = fin->fin_hlen + sizeof(udphdr_t);
  54 #ifdef  _KERNEL
  55 # if     SOLARIS
  56         m = fin->fin_qfm;
  57
  58         dlen = msgdsize(m) - off;
  59         if (dlen < 16)
  60                 return -1;
  61         copyout_mblk(m, off, MIN(sizeof(ipsec_buffer), dlen), ipsec_buffer);
  62 # else
  63         m = *(mb_t **)fin->fin_mp;
  64         dlen = mbufchainlen(m) - off;
  65         if (dlen < 16)
  66                 return -1;
  67         m_copydata(m, off, MIN(sizeof(ipsec_buffer), dlen), ipsec_buffer);
  68 # endif
  69 #else
  70         m = *(mb_t **)fin->fin_mp;
  71         dlen = ip->ip_len - off;
  72         ptr = (char *)m;
  73         ptr += off;
  74         bcopy(ptr, ipsec_buffer, MIN(sizeof(ipsec_buffer), dlen));
  75 #endif
  76
  77         /*
  78          * Because _new() gets called from nat_new(), ipf_nat is held with a
  79          * write lock so pass rw=1 to nat_outlookup().
  80          */
  81         if (nat_outlookup(fin, 0, IPPROTO_ESP, nat->nat_inip,
  82                           ip->ip_dst, 1) != NULL)
  83                 return -1;
  84
  85         aps->aps_psiz = sizeof(*ipsec);
  86         KMALLOCS(aps->aps_data, ipsec_pxy_t *, sizeof(*ipsec));
  87         if (aps->aps_data == NULL)
  88                 return -1;
  89
  90         ipsec = aps->aps_data;
  91         bzero((char *)ipsec, sizeof(*ipsec));
  92
  93         /*
  94          * Create NAT rule against which the tunnel/transport mapping is
  95          * created.  This is required because the current NAT rule does not
  96          * describe ESP but UDP instead.
  97          */
  98         ipn = &ipsec->ipsc_rule;
  99         ipn->in_ifp = fin->fin_ifp;
 100         ipn->in_apr = NULL;
 101         ipn->in_use = 1;
 102         ipn->in_hits = 1;
 103         ipn->in_nip = ntohl(nat->nat_outip.s_addr);
 104         ipn->in_ippip = 1;
 105         ipn->in_inip = nat->nat_inip.s_addr;
 106         ipn->in_inmsk = 0xffffffff;
 107         ipn->in_outip = nat->nat_outip.s_addr;
 108         ipn->in_outmsk = 0xffffffff;
 109         ipn->in_srcip = fin->fin_saddr;
 110         ipn->in_srcmsk = 0xffffffff;
 111         ipn->in_redir = NAT_MAP;
 112         bcopy(nat->nat_ptr->in_ifname, ipn->in_ifname, sizeof(ipn->in_ifname));
 113         ipn->in_p = IPPROTO_ESP;
 114
 115         bcopy((char *)fin, (char *)&fi, sizeof(fi));
 116         fi.fin_fi.fi_p = IPPROTO_ESP;
 117         fi.fin_fr = &ipsecfr;
 118         fi.fin_data[0] = 0;
 119         fi.fin_data[1] = 0;
 120         p = ip->ip_p;
 121         ip->ip_p = IPPROTO_ESP;
 122         fi.fin_fl &= ~FI_TCPUDP;
 123
 124         ptr = ipsec_buffer;
 125         bcopy(ptr, ipsec->ipsc_icookie, sizeof(ipsec_cookie_t));
 126         ptr += sizeof(ipsec_cookie_t);
 127         bcopy(ptr, ipsec->ipsc_rcookie, sizeof(ipsec_cookie_t));
 128         /*
 129          * The responder cookie should only be non-zero if the initiator
 130          * cookie is non-zero.  Therefore, it is safe to assume(!) that the
 131          * cookies are both set after copying if the responder is non-zero.
 132          */
 133         if ((ipsec->ipsc_rcookie[0]|ipsec->ipsc_rcookie[1]) != 0)
 134                 ipsec->ipsc_rckset = 1;
 135         else
 136                 nat->nat_age = 60;      /* 30 seconds */
 137
 138         ipsec->ipsc_nat = nat_new(&fi, ip, ipn, &ipsec->ipsc_nat, FI_IGNOREPKT,
 139                                    NAT_OUTBOUND);
 140         if (ipsec->ipsc_nat != NULL) {
 141                 fi.fin_data[0] = 0;
 142                 fi.fin_data[1] = 0;
 143                 ipsec->ipsc_state = fr_addstate(ip, &fi, &ipsec->ipsc_state,
 144                                                 FI_IGNOREPKT|FI_NORULE);
 145         }
 146         ip->ip_p = p;
 147         return 0;
 148 }
 149
 150
 151 /*
 152  * For outgoing IKE packets.  refresh timeouts for NAT & stat entries, if
 153  * we can.  If they have disappeared, recreate them.
 154  */
 155 int ippr_ipsec_out(fin, ip, aps, nat)
 156 fr_info_t *fin;
 157 ip_t *ip;
 158 ap_session_t *aps;
 159 nat_t *nat;
 160 {
 161         ipsec_pxy_t *ipsec;
 162         fr_info_t fi;
 163         int p;
 164
 165         bcopy((char *)fin, (char *)&fi, sizeof(fi));
 166         fi.fin_fi.fi_p = IPPROTO_ESP;
 167         fi.fin_fr = &ipsecfr;
 168         fi.fin_data[0] = 0;
 169         fi.fin_data[1] = 0;
 170         p = ip->ip_p;
 171         ip->ip_p = IPPROTO_ESP;
 172         fi.fin_fl &= ~FI_TCPUDP;
 173
 174         ipsec = aps->aps_data;
 175         if (ipsec != NULL) {
 176                 /*
 177                  * Update NAT timeout/create NAT if missing.
 178                  */
 179                 if (ipsec->ipsc_rckset == 0)
 180                         nat->nat_age = 60;      /* 30 seconds */
 181                 if (ipsec->ipsc_nat != NULL)
 182                         ipsec->ipsc_nat->nat_age = nat->nat_age;
 183                 else
 184                         ipsec->ipsc_nat = nat_new(&fi, ip, &ipsec->ipsc_rule,
 185                                                   &ipsec->ipsc_nat,
 186                                                   FI_IGNOREPKT, NAT_OUTBOUND);
 187
 188                 /*
 189                  * Update state timeout/create state if missing.
 190                  */
 191                 READ_ENTER(&ipf_state);
 192                 if (ipsec->ipsc_state != NULL) {
 193                         ipsec->ipsc_state->is_age = nat->nat_age;
 194                         RWLOCK_EXIT(&ipf_state);
 195                 } else {
 196                         RWLOCK_EXIT(&ipf_state);
 197                         fi.fin_data[0] = 0;
 198                         fi.fin_data[1] = 0;
 199                         ipsec->ipsc_state = fr_addstate(ip, &fi,
 200                                                         &ipsec->ipsc_state,
 201                                                         FI_IGNOREPKT|FI_NORULE);
 202                 }
 203         }
 204         ip->ip_p = p;
 205         return 0;
 206 }
 207
 208
 209 /*
 210  * This extends the NAT matching to be based on the cookies associated with
 211  * a session and found at the front of IKE packets.  The cookies are always
 212  * in the same order (not reversed depending on packet flow direction as with
 213  * UDP/TCP port numbers).
 214  */
 215 int ippr_ipsec_match(fin, aps, nat)
 216 fr_info_t *fin;
 217 ap_session_t *aps;
 218 nat_t *nat;
 219 {
 220         ipsec_pxy_t *ipsec;
 221         u_32_t cookies[4];
 222         mb_t *m;
 223         int off;
 224
 225         if ((fin->fin_dlen < sizeof(cookies)) || (fin->fin_fl & FI_FRAG))
 226                 return -1;
 227
 228         ipsec = aps->aps_data;
 229         off = fin->fin_hlen + sizeof(udphdr_t);
 230 #ifdef  _KERNEL
 231 # if     SOLARIS
 232         m = fin->fin_qfm;
 233
 234         copyout_mblk(m, off, sizeof(cookies), (char *)cookies);
 235 # else
 236         m = *(mb_t **)fin->fin_mp;
 237         m_copydata(m, off, sizeof(cookies), (char *)cookies);
 238 # endif
 239 #else
 240         m = *(mb_t **)fin->fin_mp;
 241         bcopy((char *)m + off, cookies, sizeof(cookies));
 242 #endif
 243
 244         if ((cookies[0] != ipsec->ipsc_icookie[0]) ||
 245             (cookies[1] != ipsec->ipsc_icookie[1]))
 246                 return -1;
 247
 248         if (ipsec->ipsc_rckset == 0) {
 249                 if ((cookies[2]|cookies[3]) == 0) {
 250                         nat->nat_age = 60;      /* 30 seconds */
 251                         return 0;
 252                 }
 253                 ipsec->ipsc_rckset = 1;
 254                 ipsec->ipsc_rcookie[0] = cookies[2];
 255                 ipsec->ipsc_rcookie[1] = cookies[3];
 256                 return 0;
 257         }
 258
 259         if ((cookies[2] != ipsec->ipsc_rcookie[0]) ||
 260             (cookies[3] != ipsec->ipsc_rcookie[1]))
 261                 return -1;
 262         return 0;
 263 }
 264
 265
 266 /*
 267  * clean up after ourselves.
 268  */
 269 void ippr_ipsec_del(aps)
 270 ap_session_t *aps;
 271 {
 272         ipsec_pxy_t *ipsec;
 273
 274         ipsec = aps->aps_data;
 275
 276         if (ipsec != NULL) {
 277                 /*
 278                  * Don't delete it from here, just schedule it to be
 279                  * deleted ASAP.
 280                  */
 281                 if (ipsec->ipsc_nat != NULL) {
 282                         ipsec->ipsc_nat->nat_age = 1;
 283                         ipsec->ipsc_nat->nat_ptr = NULL;
 284                 }
 285
 286                 READ_ENTER(&ipf_state);
 287                 if (ipsec->ipsc_state != NULL)
 288                         ipsec->ipsc_state->is_age = 1;
 289                 RWLOCK_EXIT(&ipf_state);
 290
 291                 ipsec->ipsc_state = NULL;
 292                 ipsec->ipsc_nat = NULL;
 293         }
 294 }