src/libhydra/kernel/kernel_ipsec.h

   1 /*
   2  * Copyright (C) 2006-2011 Tobias Brunner
   3  * Copyright (C) 2006 Daniel Roethlisberger
   4  * Copyright (C) 2005-2006 Martin Willi
   5  * Copyright (C) 2005 Jan Hutter
   6  * Hochschule fuer Technik Rapperswil
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the
  10  * Free Software Foundation; either version 2 of the License, or (at your
  11  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  15  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16  * for more details.
  17  */
  18
  19 /**
  20  * @defgroup kernel_ipsec kernel_ipsec
  21  * @{ @ingroup hkernel
  22  */
  23
  24 #ifndef KERNEL_IPSEC_H_
  25 #define KERNEL_IPSEC_H_
  26
  27 typedef enum ipsec_mode_t ipsec_mode_t;
  28 typedef enum policy_dir_t policy_dir_t;
  29 typedef enum policy_type_t policy_type_t;
  30 typedef enum policy_priority_t policy_priority_t;
  31 typedef enum ipcomp_transform_t ipcomp_transform_t;
  32 typedef struct kernel_ipsec_t kernel_ipsec_t;
  33 typedef struct ipsec_sa_cfg_t ipsec_sa_cfg_t;
  34 typedef struct lifetime_cfg_t lifetime_cfg_t;
  35 typedef struct mark_t mark_t;
  36
  37 #include <utils/host.h>
  38 #include <crypto/prf_plus.h>
  39 #include <selectors/traffic_selector.h>
  40 #include <plugins/plugin.h>
  41
  42 /**
  43  * Mode of an IPsec SA.
  44  */
  45 enum ipsec_mode_t {
  46         /** not using any encapsulation */
  47         MODE_NONE = 0,
  48         /** transport mode, no inner address */
  49         MODE_TRANSPORT = 1,
  50         /** tunnel mode, inner and outer addresses */
  51         MODE_TUNNEL,
  52         /** BEET mode, tunnel mode but fixed, bound inner addresses */
  53         MODE_BEET,
  54         /** passthrough policy for traffic without an IPsec SA */
  55         MODE_PASS,
  56         /** drop policy discarding traffic */
  57         MODE_DROP
  58 };
  59
  60 /**
  61  * enum names for ipsec_mode_t.
  62  */
  63 extern enum_name_t *ipsec_mode_names;
  64
  65 /**
  66  * Direction of a policy. These are equal to those
  67  * defined in xfrm.h, but we want to stay implementation
  68  * neutral here.
  69  */
  70 enum policy_dir_t {
  71         /** Policy for inbound traffic */
  72         POLICY_IN = 0,
  73         /** Policy for outbound traffic */
  74         POLICY_OUT = 1,
  75         /** Policy for forwarded traffic */
  76         POLICY_FWD = 2,
  77 };
  78
  79 /**
  80  * enum names for policy_dir_t.
  81  */
  82 extern enum_name_t *policy_dir_names;
  83
  84 /**
  85  * Type of a policy.
  86  */
  87 enum policy_type_t {
  88         /** Normal IPsec policy */
  89         POLICY_IPSEC = 1,
  90         /** Passthrough policy (traffic is ignored by IPsec) */
  91         POLICY_PASS,
  92         /** Drop policy (traffic is discarded) */
  93         POLICY_DROP,
  94 };
  95
  96 /**
  97  * High-level priority of a policy.
  98  */
  99 enum policy_priority_t {
 100         /** Default priority */
 101         POLICY_PRIORITY_DEFAULT,
 102         /** Priority for trap policies */
 103         POLICY_PRIORITY_ROUTED,
 104         /** Priority for fallback drop policies */
 105         POLICY_PRIORITY_FALLBACK,
 106 };
 107
 108 /**
 109  * IPComp transform IDs, as in RFC 4306
 110  */
 111 enum ipcomp_transform_t {
 112         IPCOMP_NONE = 0,
 113         IPCOMP_OUI = 1,
 114         IPCOMP_DEFLATE = 2,
 115         IPCOMP_LZS = 3,
 116         IPCOMP_LZJH = 4,
 117 };
 118
 119 /**
 120  * enum strings for ipcomp_transform_t.
 121  */
 122 extern enum_name_t *ipcomp_transform_names;
 123
 124 /**
 125  * This struct contains details about IPsec SA(s) tied to a policy.
 126  */
 127 struct ipsec_sa_cfg_t {
 128         /** mode of SA (tunnel, transport) */
 129         ipsec_mode_t mode;
 130         /** unique ID */
 131         u_int32_t reqid;
 132         /** details about ESP/AH */
 133         struct {
 134                 /** TRUE if this protocol is used */
 135                 bool use;
 136                 /** SPI for ESP/AH */
 137                 u_int32_t spi;
 138         } esp, ah;
 139         /** details about IPComp */
 140         struct {
 141                 /** the IPComp transform used */
 142                 u_int16_t transform;
 143                 /** CPI for IPComp */
 144                 u_int16_t cpi;
 145         } ipcomp;
 146 };
 147
 148 /**
 149  * A lifetime_cfg_t defines the lifetime limits of an SA.
 150  *
 151  * Set any of these values to 0 to ignore.
 152  */
 153 struct lifetime_cfg_t {
 154         struct {
 155                 /** Limit before the SA gets invalid. */
 156                 u_int64_t       life;
 157                 /** Limit before the SA gets rekeyed. */
 158                 u_int64_t       rekey;
 159                 /** The range of a random value subtracted from rekey. */
 160                 u_int64_t       jitter;
 161         } time, bytes, packets;
 162 };
 163
 164 /**
 165  * A mark_t defines an optional mark in an IPsec SA.
 166  */
 167 struct mark_t {
 168         /** Mark value */
 169         u_int32_t value;
 170         /** Mark mask */
 171         u_int32_t mask;
 172 };
 173
 174 /**
 175  * Interface to the ipsec subsystem of the kernel.
 176  *
 177  * The kernel ipsec interface handles the communication with the kernel
 178  * for SA and policy management. It allows setup of these, and provides
 179  * further the handling of kernel events.
 180  * Policy information are cached in the interface. This is necessary to do
 181  * reference counting. The Linux kernel does not allow the same policy
 182  * installed twice, but we need this as CHILD_SA exist multiple times
 183  * when rekeying. Thats why we do reference counting of policies.
 184  */
 185 struct kernel_ipsec_t {
 186
 187         /**
 188          * Get a SPI from the kernel.
 189          *
 190          * @param src           source address of SA
 191          * @param dst           destination address of SA
 192          * @param protocol      protocol for SA (ESP/AH)
 193          * @param reqid         unique ID for this SA
 194          * @param spi           allocated spi
 195          * @return                              SUCCESS if operation completed
 196          */
 197         status_t (*get_spi)(kernel_ipsec_t *this, host_t *src, host_t *dst,
 198                                                 u_int8_t protocol, u_int32_t reqid, u_int32_t *spi);
 199
 200         /**
 201          * Get a Compression Parameter Index (CPI) from the kernel.
 202          *
 203          * @param src           source address of SA
 204          * @param dst           destination address of SA
 205          * @param reqid         unique ID for the corresponding SA
 206          * @param cpi           allocated cpi
 207          * @return                              SUCCESS if operation completed
 208          */
 209         status_t (*get_cpi)(kernel_ipsec_t *this, host_t *src, host_t *dst,
 210                                                 u_int32_t reqid, u_int16_t *cpi);
 211
 212         /**
 213          * Add an SA to the SAD.
 214          *
 215          * add_sa() may update an already allocated
 216          * SPI (via get_spi). In this case, the replace
 217          * flag must be set.
 218          * This function does install a single SA for a
 219          * single protocol in one direction.
 220          *
 221          * @param src                   source address for this SA
 222          * @param dst                   destination address for this SA
 223          * @param spi                   SPI allocated by us or remote peer
 224          * @param protocol              protocol for this SA (ESP/AH)
 225          * @param reqid                 unique ID for this SA
 226          * @param mark                  mark for this SA
 227          * @param tfc                   Traffic Flow Confidentiality padding for this SA
 228          * @param lifetime              lifetime_cfg_t for this SA
 229          * @param enc_alg               Algorithm to use for encryption (ESP only)
 230          * @param enc_key               key to use for encryption
 231          * @param int_alg               Algorithm to use for integrity protection
 232          * @param int_key               key to use for integrity protection
 233          * @param mode                  mode of the SA (tunnel, transport)
 234          * @param ipcomp                IPComp transform to use
 235          * @param cpi                   CPI for IPComp
 236          * @param encap                 enable UDP encapsulation for NAT traversal
 237          * @param esn                   TRUE to use Extended Sequence Numbers
 238          * @param inbound               TRUE if this is an inbound SA
 239          * @param src_ts                traffic selector with BEET source address
 240          * @param dst_ts                traffic selector with BEET destination address
 241          * @return                              SUCCESS if operation completed
 242          */
 243         status_t (*add_sa) (kernel_ipsec_t *this,
 244                                                 host_t *src, host_t *dst, u_int32_t spi,
 245                                                 u_int8_t protocol, u_int32_t reqid,
 246                                                 mark_t mark, u_int32_t tfc, lifetime_cfg_t *lifetime,
 247                                                 u_int16_t enc_alg, chunk_t enc_key,
 248                                                 u_int16_t int_alg, chunk_t int_key,
 249                                                 ipsec_mode_t mode, u_int16_t ipcomp, u_int16_t cpi,
 250                                                 bool encap, bool esn, bool inbound,
 251                                                 traffic_selector_t *src_ts, traffic_selector_t *dst_ts);
 252
 253         /**
 254          * Update the hosts on an installed SA.
 255          *
 256          * We cannot directly update the destination address as the kernel
 257          * requires the spi, the protocol AND the destination address (and family)
 258          * to identify SAs. Therefore if the destination address changed we
 259          * create a new SA and delete the old one.
 260          *
 261          * @param spi                   SPI of the SA
 262          * @param protocol              protocol for this SA (ESP/AH)
 263          * @param cpi                   CPI for IPComp, 0 if no IPComp is used
 264          * @param src                   current source address
 265          * @param dst                   current destination address
 266          * @param new_src               new source address
 267          * @param new_dst               new destination address
 268          * @param encap                 current use of UDP encapsulation
 269          * @param new_encap             new use of UDP encapsulation
 270          * @param mark                  optional mark for this SA
 271          * @return                              SUCCESS if operation completed, NOT_SUPPORTED if
 272          *                                        the kernel interface can't update the SA
 273          */
 274         status_t (*update_sa)(kernel_ipsec_t *this,
 275                                                   u_int32_t spi, u_int8_t protocol, u_int16_t cpi,
 276                                                   host_t *src, host_t *dst,
 277                                                   host_t *new_src, host_t *new_dst,
 278                                                   bool encap, bool new_encap, mark_t mark);
 279
 280         /**
 281          * Query the number of bytes processed by an SA from the SAD.
 282          *
 283          * @param src                   source address for this SA
 284          * @param dst                   destination address for this SA
 285          * @param spi                   SPI allocated by us or remote peer
 286          * @param protocol              protocol for this SA (ESP/AH)
 287          * @param mark                  optional mark for this SA
 288          * @param[out] bytes    the number of bytes processed by SA
 289          * @return                              SUCCESS if operation completed
 290          */
 291         status_t (*query_sa) (kernel_ipsec_t *this, host_t *src, host_t *dst,
 292                                                   u_int32_t spi, u_int8_t protocol, mark_t mark,
 293                                                   u_int64_t *bytes);
 294
 295         /**
 296          * Delete a previusly installed SA from the SAD.
 297          *
 298          * @param src                   source address for this SA
 299          * @param dst                   destination address for this SA
 300          * @param spi                   SPI allocated by us or remote peer
 301          * @param protocol              protocol for this SA (ESP/AH)
 302          * @param cpi                   CPI for IPComp or 0
 303          * @param mark                  optional mark for this SA
 304          * @return                              SUCCESS if operation completed
 305          */
 306         status_t (*del_sa) (kernel_ipsec_t *this, host_t *src, host_t *dst,
 307                                                 u_int32_t spi, u_int8_t protocol, u_int16_t cpi,
 308                                                 mark_t mark);
 309
 310         /**
 311          * Flush all SAs from the SAD.
 312          *
 313          * @return                              SUCCESS if operation completed
 314          */
 315         status_t (*flush_sas) (kernel_ipsec_t *this);
 316
 317         /**
 318          * Add a policy to the SPD.
 319          *
 320          * A policy is always associated to an SA. Traffic which matches a
 321          * policy is handled by the SA with the same reqid.
 322          *
 323          * @param src                   source address of SA
 324          * @param dst                   dest address of SA
 325          * @param src_ts                traffic selector to match traffic source
 326          * @param dst_ts                traffic selector to match traffic dest
 327          * @param direction             direction of traffic, POLICY_(IN|OUT|FWD)
 328          * @param type                  type of policy, POLICY_(IPSEC|PASS|DROP)
 329          * @param sa                    details about the SA(s) tied to this policy
 330          * @param mark                  mark for this policy
 331          * @param priority              priority of this policy
 332          * @return                              SUCCESS if operation completed
 333          */
 334         status_t (*add_policy) (kernel_ipsec_t *this,
 335                                                         host_t *src, host_t *dst,
 336                                                         traffic_selector_t *src_ts,
 337                                                         traffic_selector_t *dst_ts,
 338                                                         policy_dir_t direction, policy_type_t type,
 339                                                         ipsec_sa_cfg_t *sa, mark_t mark,
 340                                                         policy_priority_t priority);
 341
 342         /**
 343          * Query the use time of a policy.
 344          *
 345          * The use time of a policy is the time the policy was used for the last
 346          * time. It is not the system time, but a monotonic timestamp as returned
 347          * by time_monotonic.
 348          *
 349          * @param src_ts                traffic selector to match traffic source
 350          * @param dst_ts                traffic selector to match traffic dest
 351          * @param direction             direction of traffic, POLICY_(IN|OUT|FWD)
 352          * @param mark                  optional mark
 353          * @param[out] use_time the monotonic timestamp of this SA's last use
 354          * @return                              SUCCESS if operation completed
 355          */
 356         status_t (*query_policy) (kernel_ipsec_t *this,
 357                                                           traffic_selector_t *src_ts,
 358                                                           traffic_selector_t *dst_ts,
 359                                                           policy_dir_t direction, mark_t mark,
 360                                                           u_int32_t *use_time);
 361
 362         /**
 363          * Remove a policy from the SPD.
 364          *
 365          * The kernel interface implements reference counting for policies.
 366          * If the same policy is installed multiple times (in the case of rekeying),
 367          * the reference counter is increased. del_policy() decreases the ref counter
 368          * and removes the policy only when no more references are available.
 369          *
 370          * @param src_ts                traffic selector to match traffic source
 371          * @param dst_ts                traffic selector to match traffic dest
 372          * @param direction             direction of traffic, POLICY_(IN|OUT|FWD)
 373          * @param reqid                 unique ID of the associated SA
 374          * @param mark                  optional mark
 375          * @param priority              priority of the policy
 376          * @return                              SUCCESS if operation completed
 377          */
 378         status_t (*del_policy) (kernel_ipsec_t *this,
 379                                                         traffic_selector_t *src_ts,
 380                                                         traffic_selector_t *dst_ts,
 381                                                         policy_dir_t direction, u_int32_t reqid,
 382                                                         mark_t mark, policy_priority_t priority);
 383
 384         /**
 385          * Flush all policies from the SPD.
 386          *
 387          * @return                              SUCCESS if operation completed
 388          */
 389         status_t (*flush_policies) (kernel_ipsec_t *this);
 390
 391         /**
 392          * Install a bypass policy for the given socket.
 393          *
 394          * @param fd                    socket file descriptor to setup policy for
 395          * @param family                protocol family of the socket
 396          * @return                              TRUE of policy set up successfully
 397          */
 398         bool (*bypass_socket)(kernel_ipsec_t *this, int fd, int family);
 399
 400         /**
 401          * Destroy the implementation.
 402          */
 403         void (*destroy) (kernel_ipsec_t *this);
 404 };
 405
 406 /**
 407  * Helper function to (un-)register IPsec kernel interfaces from plugin features.
 408  *
 409  * This function is a plugin_feature_callback_t and can be used with the
 410  * PLUGIN_CALLBACK macro to register an IPsec kernel interface constructor.
 411  *
 412  * @param plugin                plugin registering the kernel interface
 413  * @param feature               associated plugin feature
 414  * @param reg                   TRUE to register, FALSE to unregister
 415  * @param data                  data passed to callback, an kernel_ipsec_constructor_t
 416  */
 417 bool kernel_ipsec_register(plugin_t *plugin, plugin_feature_t *feature,
 418                                                    bool reg, void *data);
 419
 420 #endif /** KERNEL_IPSEC_H_ @}*/