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 extern uint64_t now_global;
 152 extern struct timeval tv_now_global;
 153
 154 static const uint64_t       *const now    = &now_global;
 155 static const struct timeval *const tv_now = &tv_now_global;
 156
 157 /* "now" is current program time, in milliseconds. It is derived
 158    from tv_now. Both are provided by the event loop. */
 159
 160 /***** END of utility functions *****/
 161
 162 /***** SCHEDULING support */
 163
 164 /* If nfds_io is insufficient for your needs, set it to the required
 165    number and return ERANGE. timeout is in milliseconds; if it is too
 166    high then lower it. It starts at -1 (==infinite) */
 167 typedef int beforepoll_fn(void *st, struct pollfd *fds, int *nfds_io,
 168                           int *timeout_io);
 169 typedef void afterpoll_fn(void *st, struct pollfd *fds, int nfds);
 170
 171 /* Register interest in the main loop of the program. Before a call
 172    to poll() your supplied beforepoll function will be called. After
 173    the call to poll() the supplied afterpoll function will be called.
 174    max_nfds is a _hint_ about the maximum number of struct pollfd
 175    structures you may require - you can always ask for more in
 176    *nfds_io. */
 177 extern void register_for_poll(void *st, beforepoll_fn *before,
 178                               afterpoll_fn *after, int32_t max_nfds,
 179                               cstring_t desc);
 180
 181 /***** END of scheduling support */
 182
 183 /***** PROGRAM LIFETIME support */
 184
 185 /* The secnet program goes through a number of phases in its lifetime.
 186    Module code may arrange to be called just as various phases are
 187    entered.
 188
 189    Remember to update the table in util.c if changing the set of
 190    phases. */
 191
 192 enum phase {
 193     PHASE_INIT,
 194     PHASE_GETOPTS,             /* Process command-line arguments */
 195     PHASE_READCONFIG,          /* Parse and process configuration file */
 196     PHASE_SETUP,               /* Process information in configuration */
 197     PHASE_DAEMONIZE,           /* Become a daemon (if necessary) */
 198     PHASE_GETRESOURCES,        /* Obtain all external resources */
 199     PHASE_DROPPRIV,            /* Last chance for privileged operations */
 200     PHASE_RUN,
 201     PHASE_SHUTDOWN,            /* About to die; delete key material, etc. */
 202     /* Keep this last: */
 203     NR_PHASES,
 204 };
 205
 206 typedef void hook_fn(void *self, uint32_t newphase);
 207 bool_t add_hook(uint32_t phase, hook_fn *f, void *state);
 208 bool_t remove_hook(uint32_t phase, hook_fn *f, void *state);
 209
 210 extern uint32_t current_phase;
 211 extern void enter_phase(uint32_t new_phase);
 212
 213 /* Some features (like netlink 'soft' routes) require that secnet
 214    retain root privileges.  They should indicate that here when
 215    appropriate. */
 216 extern bool_t require_root_privileges;
 217 extern cstring_t require_root_privileges_explanation;
 218
 219 /***** END of program lifetime support *****/
 220
 221 /***** MODULE support *****/
 222
 223 /* Module initialisation function type - modules export one function of
 224    this type which is called to initialise them. For dynamically loaded
 225    modules it's called "secnet_module". */
 226 typedef void init_module(dict_t *dict);
 227
 228 extern void init_builtin_modules(dict_t *dict);
 229
 230 extern init_module resolver_module;
 231 extern init_module random_module;
 232 extern init_module udp_module;
 233 extern init_module util_module;
 234 extern init_module site_module;
 235 extern init_module transform_module;
 236 extern init_module netlink_module;
 237 extern init_module rsa_module;
 238 extern init_module dh_module;
 239 extern init_module md5_module;
 240 extern init_module slip_module;
 241 extern init_module tun_module;
 242 extern init_module sha1_module;
 243 extern init_module log_module;
 244
 245 /***** END of module support *****/
 246
 247 /***** CLOSURE TYPES and interface definitions *****/
 248
 249 #define CL_PURE         0
 250 #define CL_RESOLVER     1
 251 #define CL_RANDOMSRC    2
 252 #define CL_RSAPUBKEY    3
 253 #define CL_RSAPRIVKEY   4
 254 #define CL_COMM         5
 255 #define CL_IPIF         6
 256 #define CL_LOG          7
 257 #define CL_SITE         8
 258 #define CL_TRANSFORM    9
 259 #define CL_DH          11
 260 #define CL_HASH        12
 261 #define CL_BUFFER      13
 262 #define CL_NETLINK     14
 263
 264 struct buffer_if;
 265
 266 /* PURE closure requires no interface */
 267
 268 /* RESOLVER interface */
 269
 270 /* Answers to queries are delivered to a function of this
 271    type. 'address' will be NULL if there was a problem with the query. It
 272    will be freed once resolve_answer_fn returns. It is in network byte
 273    order. */
 274 /* XXX extend to be able to provide multiple answers */
 275 typedef void resolve_answer_fn(void *st, struct in_addr *addr);
 276 typedef bool_t resolve_request_fn(void *st, cstring_t name,
 277                                   resolve_answer_fn *cb, void *cst);
 278 struct resolver_if {
 279     void *st;
 280     resolve_request_fn *request;
 281 };
 282
 283 /* RANDOMSRC interface */
 284
 285 /* Return some random data. Returns TRUE for success. */
 286 typedef bool_t random_fn(void *st, int32_t bytes, uint8_t *buff);
 287
 288 struct random_if {
 289     void *st;
 290     bool_t blocking;
 291     random_fn *generate;
 292 };
 293
 294 /* RSAPUBKEY interface */
 295
 296 typedef bool_t rsa_checksig_fn(void *st, uint8_t *data, int32_t datalen,
 297                                cstring_t signature);
 298 struct rsapubkey_if {
 299     void *st;
 300     rsa_checksig_fn *check;
 301 };
 302
 303 /* RSAPRIVKEY interface */
 304
 305 typedef string_t rsa_makesig_fn(void *st, uint8_t *data, int32_t datalen);
 306 struct rsaprivkey_if {
 307     void *st;
 308     rsa_makesig_fn *sign;
 309 };
 310
 311 /* COMM interface */
 312
 313 struct comm_addr {
 314     /* This struct is pure data; in particular comm's clients may
 315        freely copy it. */
 316     /* Everyone is also guaranteed that all padding is set to zero, ie
 317        that comm_addrs referring to semantically identical peers will
 318        compare equal with memcmp.  Anyone who constructs a comm_addr
 319        must start by memsetting it with FILLZERO, or some
 320        equivalent. */
 321     struct comm_if *comm;
 322     struct sockaddr_in sin;
 323 };
 324
 325 /* Return True if the packet was processed, and shouldn't be passed to
 326    any other potential receivers. */
 327 typedef bool_t comm_notify_fn(void *state, struct buffer_if *buf,
 328                               const struct comm_addr *source);
 329 typedef void comm_request_notify_fn(void *commst, void *nst,
 330                                     comm_notify_fn *fn);
 331 typedef void comm_release_notify_fn(void *commst, void *nst,
 332                                     comm_notify_fn *fn);
 333 typedef bool_t comm_sendmsg_fn(void *commst, struct buffer_if *buf,
 334                                const struct comm_addr *dest);
 335 typedef const char *comm_addr_to_string_fn(void *commst,
 336                                            const struct comm_addr *ca);
 337         /* Returned string is in a static buffer. */
 338 struct comm_if {
 339     void *st;
 340     int32_t min_start_pad;
 341     int32_t min_end_pad;
 342     comm_request_notify_fn *request_notify;
 343     comm_release_notify_fn *release_notify;
 344     comm_sendmsg_fn *sendmsg;
 345     comm_addr_to_string_fn *addr_to_string;
 346 };
 347
 348 /* LOG interface */
 349
 350 typedef void log_msg_fn(void *st, int class, const char *message, ...);
 351 typedef void log_vmsg_fn(void *st, int class, const char *message,
 352                          va_list args);
 353 struct log_if {
 354     void *st;
 355     log_msg_fn *log;
 356     log_vmsg_fn *vlog;
 357 };
 358 /* (convenience functions, defined in util.c) */
 359 extern void slilog(struct log_if *lf, int class, const char *message, ...)
 360 FORMAT(printf,3,4);
 361 extern void vslilog(struct log_if *lf, int class, const char *message, va_list)
 362 FORMAT(printf,3,0);
 363
 364 /* SITE interface */
 365
 366 /* Pretty much a placeholder; allows starting and stopping of processing,
 367    key expiry, etc. */
 368 typedef void site_control_fn(void *st, bool_t run);
 369 typedef uint32_t site_status_fn(void *st);
 370 struct site_if {
 371     void *st;
 372     site_control_fn *control;
 373     site_status_fn *status;
 374 };
 375
 376 /* TRANSFORM interface */
 377
 378 /* A reversable transformation. Transforms buffer in-place; may add
 379    data to start or end. Maximum amount of data to be added specified
 380    in max_start_pad and max_end_pad. (Reverse transformations decrease
 381    length, of course.)  Transformations may be key-dependent, in which
 382    case key material is passed in at initialisation time. They may
 383    also depend on internal factors (eg. time) and keep internal
 384    state. A struct transform_if only represents a particular type of
 385    transformation; instances of the transformation (eg. with
 386    particular key material) have a different C type. */
 387
 388 typedef struct transform_inst_if *transform_createinstance_fn(void *st);
 389 typedef bool_t transform_setkey_fn(void *st, uint8_t *key, int32_t keylen);
 390 typedef bool_t transform_valid_fn(void *st); /* 0: no key; 1: ok */
 391 typedef void transform_delkey_fn(void *st);
 392 typedef void transform_destroyinstance_fn(void *st);
 393 /* Returns:
 394  *   0: all is well
 395  *   1: for any other problem
 396  *   2: message decrypted but sequence number was out of range
 397  */
 398 typedef uint32_t transform_apply_fn(void *st, struct buffer_if *buf,
 399                                     const char **errmsg);
 400
 401 struct transform_inst_if {
 402     void *st;
 403     transform_setkey_fn *setkey;
 404     transform_valid_fn *valid;
 405     transform_delkey_fn *delkey;
 406     transform_apply_fn *forwards;
 407     transform_apply_fn *reverse;
 408     transform_destroyinstance_fn *destroy;
 409 };
 410
 411 struct transform_if {
 412     void *st;
 413     int32_t max_start_pad; /* these three are all <<< INT_MAX */
 414     int32_t max_end_pad;
 415     int32_t keylen;
 416     transform_createinstance_fn *create;
 417 };
 418
 419 /* NETLINK interface */
 420
 421 /* Used by netlink to deliver to site, and by site to deliver to
 422    netlink.  cid is the client identifier returned by
 423    netlink_regnets_fn.  If buf has size 0 then the function is just
 424    being called for its site-effects (eg. making the site code attempt
 425    to bring up a network link) */
 426 typedef void netlink_deliver_fn(void *st, struct buffer_if *buf);
 427 /* site code can tell netlink when outgoing packets will be dropped,
 428    so netlink can generate appropriate ICMP and make routing decisions */
 429 #define LINK_QUALITY_UNUSED 0   /* This link is unused, do not make this netlink */
 430 #define LINK_QUALITY_DOWN 1   /* No chance of a packet being delivered right away*/
 431 #define LINK_QUALITY_DOWN_STALE_ADDRESS 2 /* Link down, old address information */
 432 #define LINK_QUALITY_DOWN_CURRENT_ADDRESS 3 /* Link down, current address information */
 433 #define LINK_QUALITY_UP 4     /* Link active */
 434 #define MAXIMUM_LINK_QUALITY 3
 435 typedef void netlink_link_quality_fn(void *st, uint32_t quality);
 436 typedef void netlink_register_fn(void *st, netlink_deliver_fn *deliver,
 437                                  void *dst, int32_t max_start_pad,
 438                                  int32_t max_end_pad);
 439 typedef void netlink_output_config_fn(void *st, struct buffer_if *buf);
 440 typedef bool_t netlink_check_config_fn(void *st, struct buffer_if *buf);
 441 typedef void netlink_set_mtu_fn(void *st, int32_t new_mtu);
 442 struct netlink_if {
 443     void *st;
 444     netlink_register_fn *reg;
 445     netlink_deliver_fn *deliver;
 446     netlink_link_quality_fn *set_quality;
 447     netlink_set_mtu_fn *set_mtu;
 448 };
 449
 450 /* DH interface */
 451
 452 /* Returns public key as a malloced hex string */
 453 typedef string_t dh_makepublic_fn(void *st, uint8_t *secret,
 454                                   int32_t secretlen);
 455 /* Fills buffer (up to buflen) with shared secret */
 456 typedef void dh_makeshared_fn(void *st, uint8_t *secret,
 457                               int32_t secretlen, cstring_t rempublic,
 458                               uint8_t *sharedsecret, int32_t buflen);
 459 struct dh_if {
 460     void *st;
 461     int32_t len; /* Approximate size of modulus in bytes */
 462     dh_makepublic_fn *makepublic;
 463     dh_makeshared_fn *makeshared;
 464 };
 465
 466 /* HASH interface */
 467
 468 typedef void *hash_init_fn(void);
 469 typedef void hash_update_fn(void *st, const void *buf, int32_t len);
 470 typedef void hash_final_fn(void *st, uint8_t *digest);
 471 struct hash_if {
 472     int32_t len; /* Hash output length in bytes */
 473     hash_init_fn *init;
 474     hash_update_fn *update;
 475     hash_final_fn *final;
 476 };
 477
 478 /* BUFFER interface */
 479
 480 struct buffer_if {
 481     bool_t free;
 482     cstring_t owner; /* Set to constant string */
 483     uint32_t flags; /* How paranoid should we be? */
 484     struct cloc loc; /* Where we were defined */
 485     uint8_t *base;
 486     uint8_t *start;
 487     int32_t size; /* Size of buffer contents */
 488     int32_t len; /* Total length allocated at base */
 489 };
 490
 491 /***** LOG functions *****/
 492
 493 #define M_DEBUG_CONFIG 0x001
 494 #define M_DEBUG_PHASE  0x002
 495 #define M_DEBUG        0x004
 496 #define M_INFO         0x008
 497 #define M_NOTICE       0x010
 498 #define M_WARNING      0x020
 499 #define M_ERR          0x040
 500 #define M_SECURITY     0x080
 501 #define M_FATAL        0x100
 502
 503 /* The fatal() family of functions require messages that do not end in '\n' */
 504 extern NORETURN(fatal(const char *message, ...));
 505 extern NORETURN(fatal_perror(const char *message, ...));
 506 extern NORETURN(fatal_status(int status, const char *message, ...));
 507 extern NORETURN(fatal_perror_status(int status, const char *message, ...));
 508
 509 /* The cfgfatal() family of functions require messages that end in '\n' */
 510 extern NORETURN(cfgfatal(struct cloc loc, cstring_t facility,
 511                          const char *message, ...));
 512 extern void cfgfile_postreadcheck(struct cloc loc, FILE *f);
 513 extern NORETURN(vcfgfatal_maybefile(FILE *maybe_f, struct cloc loc,
 514                                     cstring_t facility, const char *message,
 515                                     va_list));
 516 extern NORETURN(cfgfatal_maybefile(FILE *maybe_f, struct cloc loc,
 517                                    cstring_t facility,
 518                                    const char *message, ...));
 519
 520 extern void Message(uint32_t class, const char *message, ...)
 521     FORMAT(printf,2,3);
 522 extern void log_from_fd(int fd, cstring_t prefix, struct log_if *log);
 523
 524 /***** END of log functions *****/
 525
 526 #define STRING2(x) #x
 527 #define STRING(x) STRING2(x)
 528
 529 #define FILLZERO(obj) (memset(&(obj),0,sizeof((obj))))
 530
 531 #endif /* secnet_h */