mdw@git.distorted.org.uk Git - secnet/blob - secnet.h

   1 /* Core interface of secnet, to be used by all modules */
   2
   3 #ifndef secnet_h
   4 #define secnet_h
   5
   6 #include "config.h"
   7 #include <stdlib.h>
   8 #include <stdarg.h>
   9 #include <stdio.h>
  10 #include <sys/poll.h>
  11 #include <sys/types.h>
  12 #include <sys/time.h>
  13 #include <netinet/in.h>
  14
  15 /*
  16  * Macros added by SGT for endianness-independence
  17  */
  18 #define GET_32BIT_MSB_FIRST(cp) \
  19   (((unsigned long)(unsigned char)(cp)[0] << 24) | \
  20   ((unsigned long)(unsigned char)(cp)[1] << 16) | \
  21   ((unsigned long)(unsigned char)(cp)[2] << 8) | \
  22   ((unsigned long)(unsigned char)(cp)[3]))
  23
  24 #define PUT_32BIT_MSB_FIRST(cp, value) ( \
  25   (cp)[0] = (char)((value) >> 24), \
  26   (cp)[1] = (char)((value) >> 16), \
  27   (cp)[2] = (char)((value) >> 8), \
  28   (cp)[3] = (char)(value) )
  29
  30 typedef char *string_t;
  31 typedef const char *cstring_t;
  32 typedef enum {False,True} bool_t;
  33
  34 #define ASSERT(x) do { if (!(x)) { fatal("assertion failed line %d file " \
  35                                          __FILE__,__LINE__); } } while(0)
  36
  37 /* from version.c */
  38
  39 extern char version[];
  40
  41 /* from logmsg.c */
  42 extern uint32_t message_level;
  43 extern bool_t secnet_is_daemon;
  44 extern struct log_if *system_log;
  45
  46 /* from process.c */
  47 extern void start_signal_handling(void);
  48
  49 /***** CONFIGURATION support *****/
  50
  51 extern bool_t just_check_config; /* If True then we're going to exit after
  52                                     reading the configuration file */
  53 extern bool_t background; /* If True then we'll eventually run as a daemon */
  54
  55 typedef struct dict dict_t;        /* Configuration dictionary */
  56 typedef struct closure closure_t;
  57 typedef struct item item_t;
  58 typedef struct list list_t;        /* A list of items */
  59
  60 /* Configuration file location, for error-reporting */
  61 struct cloc {
  62     cstring_t file;
  63     int line;
  64 };
  65
  66 /* Modules export closures, which can be invoked from the configuration file.
  67    "Invoking" a closure usually returns another closure (of a different
  68    type), but can actually return any configuration object. */
  69 typedef list_t *(apply_fn)(closure_t *self, struct cloc loc,
  70                            dict_t *context, list_t *data);
  71 struct closure {
  72     cstring_t description; /* For debugging */
  73     uint32_t type; /* Central registry... */
  74     apply_fn *apply;
  75     void *interface; /* Interface for use inside secnet; depends on type */
  76 };
  77
  78 enum types { t_null, t_bool, t_string, t_number, t_dict, t_closure };
  79 struct item {
  80     enum types type;
  81     union {
  82         bool_t bool;
  83         string_t string;
  84         uint32_t number;
  85         dict_t *dict;
  86         closure_t *closure;
  87     } data;
  88     struct cloc loc;
  89 };
  90
  91 /* Note that it is unwise to use this structure directly; use the list
  92    manipulation functions instead. */
  93 struct list {
  94     item_t *item;
  95     struct list *next;
  96 };
  97
  98 /* In the following two lookup functions, NULL means 'not found' */
  99 /* Lookup a value in the specified dictionary, or its parents */
 100 extern list_t *dict_lookup(dict_t *dict, cstring_t key);
 101 /* Lookup a value in just the specified dictionary */
 102 extern list_t *dict_lookup_primitive(dict_t *dict, cstring_t key);
 103 /* Add a value to the specified dictionary */
 104 extern void dict_add(dict_t *dict, cstring_t key, list_t *val);
 105 /* Obtain an array of keys in the dictionary. malloced; caller frees */
 106 extern cstring_t *dict_keys(dict_t *dict);
 107
 108 /* List-manipulation functions */
 109 extern list_t *list_new(void);
 110 extern int32_t list_length(list_t *a);
 111 extern list_t *list_append(list_t *a, item_t *i);
 112 extern list_t *list_append_list(list_t *a, list_t *b);
 113 /* Returns an item from the list (index starts at 0), or NULL */
 114 extern item_t *list_elem(list_t *l, int32_t index);
 115
 116 /* Convenience functions */
 117 extern list_t *new_closure(closure_t *cl);
 118 extern void add_closure(dict_t *dict, cstring_t name, apply_fn apply);
 119 extern void *find_cl_if(dict_t *dict, cstring_t name, uint32_t type,
 120                         bool_t fail_if_invalid, cstring_t desc,
 121                         struct cloc loc);
 122 extern item_t *dict_find_item(dict_t *dict, cstring_t key, bool_t required,
 123                               cstring_t desc, struct cloc loc);
 124 extern string_t dict_read_string(dict_t *dict, cstring_t key, bool_t required,
 125                                  cstring_t desc, struct cloc loc);
 126 extern uint32_t dict_read_number(dict_t *dict, cstring_t key, bool_t required,
 127                                  cstring_t desc, struct cloc loc,
 128                                  uint32_t def);
 129   /* return value can safely be assigned to int32_t */
 130 extern bool_t dict_read_bool(dict_t *dict, cstring_t key, bool_t required,
 131                              cstring_t desc, struct cloc loc, bool_t def);
 132 struct flagstr {
 133     cstring_t name;
 134     uint32_t value;
 135 };
 136 extern uint32_t string_to_word(cstring_t s, struct cloc loc,
 137                                struct flagstr *f, cstring_t desc);
 138 extern uint32_t string_list_to_word(list_t *l, struct flagstr *f,
 139                                     cstring_t desc);
 140
 141 /***** END of configuration support *****/
 142
 143 /***** UTILITY functions *****/
 144
 145 extern char *safe_strdup(const char *string, const char *message);
 146 extern void *safe_malloc(size_t size, const char *message);
 147 extern void *safe_malloc_ary(size_t size, size_t count, const char *message);
 148
 149 extern int sys_cmd(const char *file, const char *argc, ...);
 150
 151 /***** END of utility functions *****/
 152
 153 /***** SCHEDULING support */
 154
 155 /* "now" is current program time, in milliseconds. It is derived
 156    (once) from tv_now. If nfds_io is insufficient for your needs, set
 157    it to the required number and return ERANGE. timeout is in milliseconds;
 158    if it is too high then lower it. It starts at -1 (==infinite) */
 159 typedef int beforepoll_fn(void *st, struct pollfd *fds, int *nfds_io,
 160                           int *timeout_io, const struct timeval *tv_now,
 161                           uint64_t *now);
 162 typedef void afterpoll_fn(void *st, struct pollfd *fds, int nfds,
 163                           const struct timeval *tv_now, uint64_t *now);
 164
 165 /* Register interest in the main loop of the program. Before a call
 166    to poll() your supplied beforepoll function will be called. After
 167    the call to poll() the supplied afterpoll function will be called.
 168    max_nfds is a _hint_ about the maximum number of struct pollfd
 169    structures you may require - you can always ask for more in
 170    *nfds_io. */
 171 extern void register_for_poll(void *st, beforepoll_fn *before,
 172                               afterpoll_fn *after, int32_t max_nfds,
 173                               cstring_t desc);
 174
 175 /***** END of scheduling support */
 176
 177 /***** PROGRAM LIFETIME support */
 178
 179 /* The secnet program goes through a number of phases in its lifetime.
 180    Module code may arrange to be called just as various phases are
 181    entered. */
 182
 183 #define PHASE_INIT          0
 184 #define PHASE_GETOPTS       1  /* Process command-line arguments */
 185 #define PHASE_READCONFIG    2  /* Parse and process configuration file */
 186 #define PHASE_SETUP         3  /* Process information in configuration */
 187 #define PHASE_GETRESOURCES  4  /* Obtain all external resources */
 188 #define PHASE_DROPPRIV      5  /* Last chance for privileged operations */
 189 #define PHASE_RUN           6
 190 #define PHASE_SHUTDOWN      7  /* About to die; delete key material, etc. */
 191 #define NR_PHASES           8
 192
 193 typedef void hook_fn(void *self, uint32_t newphase);
 194 bool_t add_hook(uint32_t phase, hook_fn *f, void *state);
 195 bool_t remove_hook(uint32_t phase, hook_fn *f, void *state);
 196
 197 extern uint32_t current_phase;
 198 extern void enter_phase(uint32_t new_phase);
 199
 200 /* Some features (like netlink 'soft' routes) require that secnet
 201    retain root privileges.  They should indicate that here when
 202    appropriate. */
 203 extern bool_t require_root_privileges;
 204 extern cstring_t require_root_privileges_explanation;
 205
 206 /***** END of program lifetime support *****/
 207
 208 /***** MODULE support *****/
 209
 210 /* Module initialisation function type - modules export one function of
 211    this type which is called to initialise them. For dynamically loaded
 212    modules it's called "secnet_module". */
 213 typedef void init_module(dict_t *dict);
 214
 215 extern void init_builtin_modules(dict_t *dict);
 216
 217 extern init_module resolver_module;
 218 extern init_module random_module;
 219 extern init_module udp_module;
 220 extern init_module util_module;
 221 extern init_module site_module;
 222 extern init_module transform_module;
 223 extern init_module netlink_module;
 224 extern init_module rsa_module;
 225 extern init_module dh_module;
 226 extern init_module md5_module;
 227 extern init_module slip_module;
 228 extern init_module tun_module;
 229 extern init_module sha1_module;
 230 extern init_module log_module;
 231
 232 /***** END of module support *****/
 233
 234 /***** CLOSURE TYPES and interface definitions *****/
 235
 236 #define CL_PURE         0
 237 #define CL_RESOLVER     1
 238 #define CL_RANDOMSRC    2
 239 #define CL_RSAPUBKEY    3
 240 #define CL_RSAPRIVKEY   4
 241 #define CL_COMM         5
 242 #define CL_IPIF         6
 243 #define CL_LOG          7
 244 #define CL_SITE         8
 245 #define CL_TRANSFORM    9
 246 #define CL_DH          11
 247 #define CL_HASH        12
 248 #define CL_BUFFER      13
 249 #define CL_NETLINK     14
 250
 251 struct buffer_if;
 252
 253 /* PURE closure requires no interface */
 254
 255 /* RESOLVER interface */
 256
 257 /* Answers to queries are delivered to a function of this
 258    type. 'address' will be NULL if there was a problem with the query. It
 259    will be freed once resolve_answer_fn returns. It is in network byte
 260    order. */
 261 /* XXX extend to be able to provide multiple answers */
 262 typedef void resolve_answer_fn(void *st, struct in_addr *addr);
 263 typedef bool_t resolve_request_fn(void *st, cstring_t name,
 264                                   resolve_answer_fn *cb, void *cst);
 265 struct resolver_if {
 266     void *st;
 267     resolve_request_fn *request;
 268 };
 269
 270 /* RANDOMSRC interface */
 271
 272 /* Return some random data. Returns TRUE for success. */
 273 typedef bool_t random_fn(void *st, int32_t bytes, uint8_t *buff);
 274
 275 struct random_if {
 276     void *st;
 277     bool_t blocking;
 278     random_fn *generate;
 279 };
 280
 281 /* RSAPUBKEY interface */
 282
 283 typedef bool_t rsa_checksig_fn(void *st, uint8_t *data, int32_t datalen,
 284                                cstring_t signature);
 285 struct rsapubkey_if {
 286     void *st;
 287     rsa_checksig_fn *check;
 288 };
 289
 290 /* RSAPRIVKEY interface */
 291
 292 typedef string_t rsa_makesig_fn(void *st, uint8_t *data, int32_t datalen);
 293 struct rsaprivkey_if {
 294     void *st;
 295     rsa_makesig_fn *sign;
 296 };
 297
 298 /* COMM interface */
 299
 300 /* Return True if the packet was processed, and shouldn't be passed to
 301    any other potential receivers. */
 302 typedef bool_t comm_notify_fn(void *state, struct buffer_if *buf,
 303                             struct sockaddr_in *source);
 304 typedef void comm_request_notify_fn(void *commst, void *nst,
 305                                     comm_notify_fn *fn);
 306 typedef void comm_release_notify_fn(void *commst, void *nst,
 307                                     comm_notify_fn *fn);
 308 typedef bool_t comm_sendmsg_fn(void *commst, struct buffer_if *buf,
 309                                struct sockaddr_in *dest);
 310 struct comm_if {
 311     void *st;
 312     int32_t min_start_pad;
 313     int32_t min_end_pad;
 314     comm_request_notify_fn *request_notify;
 315     comm_release_notify_fn *release_notify;
 316     comm_sendmsg_fn *sendmsg;
 317 };
 318
 319 /* LOG interface */
 320
 321 typedef void log_msg_fn(void *st, int class, const char *message, ...);
 322 typedef void log_vmsg_fn(void *st, int class, const char *message,
 323                          va_list args);
 324 struct log_if {
 325     void *st;
 326     log_msg_fn *log;
 327     log_vmsg_fn *vlog;
 328 };
 329 /* (convenience functions, defined in util.c) */
 330 extern void slilog(struct log_if *lf, int class, const char *message, ...)
 331 FORMAT(printf,3,4);
 332 extern void vslilog(struct log_if *lf, int class, const char *message, va_list)
 333 FORMAT(printf,3,0);
 334
 335 /* SITE interface */
 336
 337 /* Pretty much a placeholder; allows starting and stopping of processing,
 338    key expiry, etc. */
 339 typedef void site_control_fn(void *st, bool_t run);
 340 typedef uint32_t site_status_fn(void *st);
 341 struct site_if {
 342     void *st;
 343     site_control_fn *control;
 344     site_status_fn *status;
 345 };
 346
 347 /* TRANSFORM interface */
 348
 349 /* A reversable transformation. Transforms buffer in-place; may add
 350    data to start or end. Maximum amount of data to be added specified
 351    in max_start_pad and max_end_pad. (Reverse transformations decrease
 352    length, of course.)  Transformations may be key-dependent, in which
 353    case key material is passed in at initialisation time. They may
 354    also depend on internal factors (eg. time) and keep internal
 355    state. A struct transform_if only represents a particular type of
 356    transformation; instances of the transformation (eg. with
 357    particular key material) have a different C type. */
 358
 359 typedef struct transform_inst_if *transform_createinstance_fn(void *st);
 360 typedef bool_t transform_setkey_fn(void *st, uint8_t *key, int32_t keylen);
 361 typedef void transform_delkey_fn(void *st);
 362 typedef void transform_destroyinstance_fn(void *st);
 363 /* Returns 0 for 'all is well', any other value for a problem */
 364 typedef uint32_t transform_apply_fn(void *st, struct buffer_if *buf,
 365                                     const char **errmsg);
 366
 367 struct transform_inst_if {
 368     void *st;
 369     transform_setkey_fn *setkey;
 370     transform_delkey_fn *delkey;
 371     transform_apply_fn *forwards;
 372     transform_apply_fn *reverse;
 373     transform_destroyinstance_fn *destroy;
 374 };
 375
 376 struct transform_if {
 377     void *st;
 378     int32_t max_start_pad; /* these three are all <<< INT_MAX */
 379     int32_t max_end_pad;
 380     int32_t keylen;
 381     transform_createinstance_fn *create;
 382 };
 383
 384 /* NETLINK interface */
 385
 386 /* Used by netlink to deliver to site, and by site to deliver to
 387    netlink.  cid is the client identifier returned by
 388    netlink_regnets_fn.  If buf has size 0 then the function is just
 389    being called for its site-effects (eg. making the site code attempt
 390    to bring up a network link) */
 391 typedef void netlink_deliver_fn(void *st, struct buffer_if *buf);
 392 /* site code can tell netlink when outgoing packets will be dropped,
 393    so netlink can generate appropriate ICMP and make routing decisions */
 394 #define LINK_QUALITY_DOWN 0   /* No chance of a packet being delivered */
 395 #define LINK_QUALITY_DOWN_STALE_ADDRESS 1 /* Link down, old address information */
 396 #define LINK_QUALITY_DOWN_CURRENT_ADDRESS 2 /* Link down, current address information */
 397 #define LINK_QUALITY_UP 3     /* Link active */
 398 #define MAXIMUM_LINK_QUALITY 3
 399 typedef void netlink_link_quality_fn(void *st, uint32_t quality);
 400 typedef void netlink_register_fn(void *st, netlink_deliver_fn *deliver,
 401                                  void *dst, int32_t max_start_pad,
 402                                  int32_t max_end_pad);
 403 typedef void netlink_output_config_fn(void *st, struct buffer_if *buf);
 404 typedef bool_t netlink_check_config_fn(void *st, struct buffer_if *buf);
 405 typedef void netlink_set_mtu_fn(void *st, int32_t new_mtu);
 406 struct netlink_if {
 407     void *st;
 408     netlink_register_fn *reg;
 409     netlink_deliver_fn *deliver;
 410     netlink_link_quality_fn *set_quality;
 411     netlink_output_config_fn *output_config;
 412     netlink_check_config_fn *check_config;
 413     netlink_set_mtu_fn *set_mtu;
 414 };
 415
 416 /* DH interface */
 417
 418 /* Returns public key as a malloced hex string */
 419 typedef string_t dh_makepublic_fn(void *st, uint8_t *secret,
 420                                   int32_t secretlen);
 421 /* Fills buffer (up to buflen) with shared secret */
 422 typedef void dh_makeshared_fn(void *st, uint8_t *secret,
 423                               int32_t secretlen, cstring_t rempublic,
 424                               uint8_t *sharedsecret, int32_t buflen);
 425 struct dh_if {
 426     void *st;
 427     int32_t len; /* Approximate size of modulus in bytes */
 428     dh_makepublic_fn *makepublic;
 429     dh_makeshared_fn *makeshared;
 430 };
 431
 432 /* HASH interface */
 433
 434 typedef void *hash_init_fn(void);
 435 typedef void hash_update_fn(void *st, uint8_t const *buf, int32_t len);
 436 typedef void hash_final_fn(void *st, uint8_t *digest);
 437 struct hash_if {
 438     int32_t len; /* Hash output length in bytes */
 439     hash_init_fn *init;
 440     hash_update_fn *update;
 441     hash_final_fn *final;
 442 };
 443
 444 /* BUFFER interface */
 445
 446 struct buffer_if {
 447     bool_t free;
 448     cstring_t owner; /* Set to constant string */
 449     uint32_t flags; /* How paranoid should we be? */
 450     struct cloc loc; /* Where we were defined */
 451     uint8_t *base;
 452     uint8_t *start;
 453     int32_t size; /* Size of buffer contents */
 454     int32_t len; /* Total length allocated at base */
 455 };
 456
 457 /***** LOG functions *****/
 458
 459 #define M_DEBUG_CONFIG 0x001
 460 #define M_DEBUG_PHASE  0x002
 461 #define M_DEBUG        0x004
 462 #define M_INFO         0x008
 463 #define M_NOTICE       0x010
 464 #define M_WARNING      0x020
 465 #define M_ERR          0x040
 466 #define M_SECURITY     0x080
 467 #define M_FATAL        0x100
 468
 469 /* The fatal() family of functions require messages that do not end in '\n' */
 470 extern NORETURN(fatal(const char *message, ...));
 471 extern NORETURN(fatal_perror(const char *message, ...));
 472 extern NORETURN(fatal_status(int status, const char *message, ...));
 473 extern NORETURN(fatal_perror_status(int status, const char *message, ...));
 474
 475 /* The cfgfatal() family of functions require messages that end in '\n' */
 476 extern NORETURN(cfgfatal(struct cloc loc, cstring_t facility,
 477                          const char *message, ...));
 478 extern void cfgfile_postreadcheck(struct cloc loc, FILE *f);
 479 extern NORETURN(vcfgfatal_maybefile(FILE *maybe_f, struct cloc loc,
 480                                     cstring_t facility, const char *message,
 481                                     va_list));
 482 extern NORETURN(cfgfatal_maybefile(FILE *maybe_f, struct cloc loc,
 483                                    cstring_t facility,
 484                                    const char *message, ...));
 485
 486 extern void Message(uint32_t class, const char *message, ...)
 487     FORMAT(printf,2,3);
 488 extern void log_from_fd(int fd, cstring_t prefix, struct log_if *log);
 489
 490 /***** END of log functions *****/
 491
 492 #endif /* secnet_h */