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 typedef char *string_t;
  16 typedef const char *cstring_t;
  17 typedef enum {False,True} bool_t;
  18
  19 #define ASSERT(x) do { if (!(x)) { fatal("assertion failed line %d file " \
  20                                          __FILE__,__LINE__); } } while(0)
  21
  22 /* from version.c */
  23
  24 extern char version[];
  25
  26 /* from logmsg.c */
  27 extern uint32_t message_level;
  28 extern bool_t secnet_is_daemon;
  29 extern struct log_if *system_log;
  30
  31 /* from process.c */
  32 extern void start_signal_handling(void);
  33
  34 /***** CONFIGURATION support *****/
  35
  36 extern bool_t just_check_config; /* If True then we're going to exit after
  37                                     reading the configuration file */
  38 extern bool_t background; /* If True then we'll eventually run as a daemon */
  39
  40 typedef struct dict dict_t;        /* Configuration dictionary */
  41 typedef struct closure closure_t;
  42 typedef struct item item_t;
  43 typedef struct list list_t;        /* A list of items */
  44
  45 /* Configuration file location, for error-reporting */
  46 struct cloc {
  47     cstring_t file;
  48     int line;
  49 };
  50
  51 /* Modules export closures, which can be invoked from the configuration file.
  52    "Invoking" a closure usually returns another closure (of a different
  53    type), but can actually return any configuration object. */
  54 typedef list_t *(apply_fn)(closure_t *self, struct cloc loc,
  55                            dict_t *context, list_t *data);
  56 struct closure {
  57     cstring_t description; /* For debugging */
  58     uint32_t type; /* Central registry... */
  59     apply_fn *apply;
  60     void *interface; /* Interface for use inside secnet; depends on type */
  61 };
  62
  63 enum types { t_null, t_bool, t_string, t_number, t_dict, t_closure };
  64 struct item {
  65     enum types type;
  66     union {
  67         bool_t bool;
  68         string_t string;
  69         uint32_t number;
  70         dict_t *dict;
  71         closure_t *closure;
  72     } data;
  73     struct cloc loc;
  74 };
  75
  76 /* Note that it is unwise to use this structure directly; use the list
  77    manipulation functions instead. */
  78 struct list {
  79     item_t *item;
  80     struct list *next;
  81 };
  82
  83 /* In the following two lookup functions, NULL means 'not found' */
  84 /* Lookup a value in the specified dictionary, or its parents */
  85 extern list_t *dict_lookup(dict_t *dict, cstring_t key);
  86 /* Lookup a value in just the specified dictionary */
  87 extern list_t *dict_lookup_primitive(dict_t *dict, cstring_t key);
  88 /* Add a value to the specified dictionary */
  89 extern void dict_add(dict_t *dict, cstring_t key, list_t *val);
  90 /* Obtain an array of keys in the dictionary. malloced; caller frees */
  91 extern cstring_t *dict_keys(dict_t *dict);
  92
  93 /* List-manipulation functions */
  94 extern list_t *list_new(void);
  95 extern int32_t list_length(list_t *a);
  96 extern list_t *list_append(list_t *a, item_t *i);
  97 extern list_t *list_append_list(list_t *a, list_t *b);
  98 /* Returns an item from the list (index starts at 0), or NULL */
  99 extern item_t *list_elem(list_t *l, int32_t index);
 100
 101 /* Convenience functions */
 102 extern list_t *new_closure(closure_t *cl);
 103 extern void add_closure(dict_t *dict, cstring_t name, apply_fn apply);
 104 extern void *find_cl_if(dict_t *dict, cstring_t name, uint32_t type,
 105                         bool_t fail_if_invalid, cstring_t desc,
 106                         struct cloc loc);
 107 extern item_t *dict_find_item(dict_t *dict, cstring_t key, bool_t required,
 108                               cstring_t desc, struct cloc loc);
 109 extern string_t dict_read_string(dict_t *dict, cstring_t key, bool_t required,
 110                                  cstring_t desc, struct cloc loc);
 111 extern uint32_t dict_read_number(dict_t *dict, cstring_t key, bool_t required,
 112                                  cstring_t desc, struct cloc loc,
 113                                  uint32_t def);
 114   /* return value can safely be assigned to int32_t */
 115 extern bool_t dict_read_bool(dict_t *dict, cstring_t key, bool_t required,
 116                              cstring_t desc, struct cloc loc, bool_t def);
 117 struct flagstr {
 118     cstring_t name;
 119     uint32_t value;
 120 };
 121 extern uint32_t string_to_word(cstring_t s, struct cloc loc,
 122                                struct flagstr *f, cstring_t desc);
 123 extern uint32_t string_list_to_word(list_t *l, struct flagstr *f,
 124                                     cstring_t desc);
 125
 126 /***** END of configuration support *****/
 127
 128 /***** UTILITY functions *****/
 129
 130 extern char *safe_strdup(const char *string, const char *message);
 131 extern void *safe_malloc(size_t size, const char *message);
 132 extern void *safe_malloc_ary(size_t size, size_t count, const char *message);
 133
 134 extern int sys_cmd(const char *file, const char *argc, ...);
 135
 136 extern uint64_t now_global;
 137 extern struct timeval tv_now_global;
 138
 139 static const uint64_t       *const now    = &now_global;
 140 static const struct timeval *const tv_now = &tv_now_global;
 141
 142 /* "now" is current program time, in milliseconds. It is derived
 143    from tv_now. Both are provided by the event loop. */
 144
 145 /***** END of utility functions *****/
 146
 147 /***** SCHEDULING support */
 148
 149 /* If nfds_io is insufficient for your needs, set it to the required
 150    number and return ERANGE. timeout is in milliseconds; if it is too
 151    high then lower it. It starts at -1 (==infinite) */
 152 typedef int beforepoll_fn(void *st, struct pollfd *fds, int *nfds_io,
 153                           int *timeout_io);
 154 typedef void afterpoll_fn(void *st, struct pollfd *fds, int nfds);
 155
 156 /* Register interest in the main loop of the program. Before a call
 157    to poll() your supplied beforepoll function will be called. After
 158    the call to poll() the supplied afterpoll function will be called.
 159    max_nfds is a _hint_ about the maximum number of struct pollfd
 160    structures you may require - you can always ask for more in
 161    *nfds_io. */
 162 extern void register_for_poll(void *st, beforepoll_fn *before,
 163                               afterpoll_fn *after, int32_t max_nfds,
 164                               cstring_t desc);
 165
 166 /***** END of scheduling support */
 167
 168 /***** PROGRAM LIFETIME support */
 169
 170 /* The secnet program goes through a number of phases in its lifetime.
 171    Module code may arrange to be called just as various phases are
 172    entered.
 173
 174    Remember to update the table in util.c if changing the set of
 175    phases. */
 176
 177 enum phase {
 178     PHASE_INIT,
 179     PHASE_GETOPTS,             /* Process command-line arguments */
 180     PHASE_READCONFIG,          /* Parse and process configuration file */
 181     PHASE_SETUP,               /* Process information in configuration */
 182     PHASE_DAEMONIZE,           /* Become a daemon (if necessary) */
 183     PHASE_GETRESOURCES,        /* Obtain all external resources */
 184     PHASE_DROPPRIV,            /* Last chance for privileged operations */
 185     PHASE_RUN,
 186     PHASE_SHUTDOWN,            /* About to die; delete key material, etc. */
 187     /* Keep this last: */
 188     NR_PHASES,
 189 };
 190
 191 typedef void hook_fn(void *self, uint32_t newphase);
 192 bool_t add_hook(uint32_t phase, hook_fn *f, void *state);
 193 bool_t remove_hook(uint32_t phase, hook_fn *f, void *state);
 194
 195 extern uint32_t current_phase;
 196 extern void enter_phase(uint32_t new_phase);
 197
 198 /* Some features (like netlink 'soft' routes) require that secnet
 199    retain root privileges.  They should indicate that here when
 200    appropriate. */
 201 extern bool_t require_root_privileges;
 202 extern cstring_t require_root_privileges_explanation;
 203
 204 /***** END of program lifetime support *****/
 205
 206 /***** MODULE support *****/
 207
 208 /* Module initialisation function type - modules export one function of
 209    this type which is called to initialise them. For dynamically loaded
 210    modules it's called "secnet_module". */
 211 typedef void init_module(dict_t *dict);
 212
 213 extern void init_builtin_modules(dict_t *dict);
 214
 215 extern init_module resolver_module;
 216 extern init_module random_module;
 217 extern init_module udp_module;
 218 extern init_module util_module;
 219 extern init_module site_module;
 220 extern init_module transform_module;
 221 extern init_module netlink_module;
 222 extern init_module rsa_module;
 223 extern init_module dh_module;
 224 extern init_module md5_module;
 225 extern init_module slip_module;
 226 extern init_module tun_module;
 227 extern init_module sha1_module;
 228 extern init_module log_module;
 229
 230 /***** END of module support *****/
 231
 232 /***** CLOSURE TYPES and interface definitions *****/
 233
 234 #define CL_PURE         0
 235 #define CL_RESOLVER     1
 236 #define CL_RANDOMSRC    2
 237 #define CL_RSAPUBKEY    3
 238 #define CL_RSAPRIVKEY   4
 239 #define CL_COMM         5
 240 #define CL_IPIF         6
 241 #define CL_LOG          7
 242 #define CL_SITE         8
 243 #define CL_TRANSFORM    9
 244 #define CL_DH          11
 245 #define CL_HASH        12
 246 #define CL_BUFFER      13
 247 #define CL_NETLINK     14
 248
 249 struct buffer_if;
 250
 251 /* PURE closure requires no interface */
 252
 253 /* RESOLVER interface */
 254
 255 /* Answers to queries are delivered to a function of this
 256    type. 'address' will be NULL if there was a problem with the query. It
 257    will be freed once resolve_answer_fn returns. It is in network byte
 258    order. */
 259 /* XXX extend to be able to provide multiple answers */
 260 typedef void resolve_answer_fn(void *st, struct in_addr *addr);
 261 typedef bool_t resolve_request_fn(void *st, cstring_t name,
 262                                   resolve_answer_fn *cb, void *cst);
 263 struct resolver_if {
 264     void *st;
 265     resolve_request_fn *request;
 266 };
 267
 268 /* RANDOMSRC interface */
 269
 270 /* Return some random data. Returns TRUE for success. */
 271 typedef bool_t random_fn(void *st, int32_t bytes, uint8_t *buff);
 272
 273 struct random_if {
 274     void *st;
 275     bool_t blocking;
 276     random_fn *generate;
 277 };
 278
 279 /* RSAPUBKEY interface */
 280
 281 typedef bool_t rsa_checksig_fn(void *st, uint8_t *data, int32_t datalen,
 282                                cstring_t signature);
 283 struct rsapubkey_if {
 284     void *st;
 285     rsa_checksig_fn *check;
 286 };
 287
 288 /* RSAPRIVKEY interface */
 289
 290 typedef string_t rsa_makesig_fn(void *st, uint8_t *data, int32_t datalen);
 291 struct rsaprivkey_if {
 292     void *st;
 293     rsa_makesig_fn *sign;
 294 };
 295
 296 /* COMM interface */
 297
 298 struct comm_addr {
 299     /* This struct is pure data; in particular comm's clients may
 300        freely copy it. */
 301     /* Everyone is also guaranteed that all padding is set to zero, ie
 302        that comm_addrs referring to semantically identical peers will
 303        compare equal with memcmp.  Anyone who constructs a comm_addr
 304        must start by memsetting it with FILLZERO, or some
 305        equivalent. */
 306     struct comm_if *comm;
 307     struct sockaddr_in sin;
 308 };
 309
 310 /* Return True if the packet was processed, and shouldn't be passed to
 311    any other potential receivers. */
 312 typedef bool_t comm_notify_fn(void *state, struct buffer_if *buf,
 313                               const struct comm_addr *source);
 314 typedef void comm_request_notify_fn(void *commst, void *nst,
 315                                     comm_notify_fn *fn);
 316 typedef void comm_release_notify_fn(void *commst, void *nst,
 317                                     comm_notify_fn *fn);
 318 typedef bool_t comm_sendmsg_fn(void *commst, struct buffer_if *buf,
 319                                const struct comm_addr *dest);
 320 typedef const char *comm_addr_to_string_fn(void *commst,
 321                                            const struct comm_addr *ca);
 322         /* Returned string is in a static buffer. */
 323 struct comm_if {
 324     void *st;
 325     int32_t min_start_pad;
 326     int32_t min_end_pad;
 327     comm_request_notify_fn *request_notify;
 328     comm_release_notify_fn *release_notify;
 329     comm_sendmsg_fn *sendmsg;
 330     comm_addr_to_string_fn *addr_to_string;
 331 };
 332
 333 /* LOG interface */
 334
 335 typedef void log_msg_fn(void *st, int class, const char *message, ...);
 336 typedef void log_vmsg_fn(void *st, int class, const char *message,
 337                          va_list args);
 338 struct log_if {
 339     void *st;
 340     log_msg_fn *log;
 341     log_vmsg_fn *vlog;
 342 };
 343 /* (convenience functions, defined in util.c) */
 344 extern void slilog(struct log_if *lf, int class, const char *message, ...)
 345 FORMAT(printf,3,4);
 346 extern void vslilog(struct log_if *lf, int class, const char *message, va_list)
 347 FORMAT(printf,3,0);
 348
 349 /* SITE interface */
 350
 351 /* Pretty much a placeholder; allows starting and stopping of processing,
 352    key expiry, etc. */
 353 typedef void site_control_fn(void *st, bool_t run);
 354 typedef uint32_t site_status_fn(void *st);
 355 struct site_if {
 356     void *st;
 357     site_control_fn *control;
 358     site_status_fn *status;
 359 };
 360
 361 /* TRANSFORM interface */
 362
 363 /* A reversable transformation. Transforms buffer in-place; may add
 364    data to start or end. Maximum amount of data to be added specified
 365    in max_start_pad and max_end_pad. (Reverse transformations decrease
 366    length, of course.)  Transformations may be key-dependent, in which
 367    case key material is passed in at initialisation time. They may
 368    also depend on internal factors (eg. time) and keep internal
 369    state. A struct transform_if only represents a particular type of
 370    transformation; instances of the transformation (eg. with
 371    particular key material) have a different C type. */
 372
 373 typedef struct transform_inst_if *transform_createinstance_fn(void *st);
 374 typedef bool_t transform_setkey_fn(void *st, uint8_t *key, int32_t keylen);
 375 typedef bool_t transform_valid_fn(void *st); /* 0: no key; 1: ok */
 376 typedef void transform_delkey_fn(void *st);
 377 typedef void transform_destroyinstance_fn(void *st);
 378 /* Returns:
 379  *   0: all is well
 380  *   1: for any other problem
 381  *   2: message decrypted but sequence number was out of range
 382  */
 383 typedef uint32_t transform_apply_fn(void *st, struct buffer_if *buf,
 384                                     const char **errmsg);
 385
 386 struct transform_inst_if {
 387     void *st;
 388     transform_setkey_fn *setkey;
 389     transform_valid_fn *valid;
 390     transform_delkey_fn *delkey;
 391     transform_apply_fn *forwards;
 392     transform_apply_fn *reverse;
 393     transform_destroyinstance_fn *destroy;
 394 };
 395
 396 struct transform_if {
 397     void *st;
 398     int32_t max_start_pad; /* these three are all <<< INT_MAX */
 399     int32_t max_end_pad;
 400     int32_t keylen;
 401     transform_createinstance_fn *create;
 402 };
 403
 404 /* NETLINK interface */
 405
 406 /* Used by netlink to deliver to site, and by site to deliver to
 407    netlink.  cid is the client identifier returned by
 408    netlink_regnets_fn.  If buf has size 0 then the function is just
 409    being called for its site-effects (eg. making the site code attempt
 410    to bring up a network link) */
 411 typedef void netlink_deliver_fn(void *st, struct buffer_if *buf);
 412 /* site code can tell netlink when outgoing packets will be dropped,
 413    so netlink can generate appropriate ICMP and make routing decisions */
 414 #define LINK_QUALITY_UNUSED 0   /* This link is unused, do not make this netlink */
 415 #define LINK_QUALITY_DOWN 1   /* No chance of a packet being delivered right away*/
 416 #define LINK_QUALITY_DOWN_STALE_ADDRESS 2 /* Link down, old address information */
 417 #define LINK_QUALITY_DOWN_CURRENT_ADDRESS 3 /* Link down, current address information */
 418 #define LINK_QUALITY_UP 4     /* Link active */
 419 #define MAXIMUM_LINK_QUALITY 3
 420 typedef void netlink_link_quality_fn(void *st, uint32_t quality);
 421 typedef void netlink_register_fn(void *st, netlink_deliver_fn *deliver,
 422                                  void *dst, int32_t max_start_pad,
 423                                  int32_t max_end_pad);
 424 typedef void netlink_output_config_fn(void *st, struct buffer_if *buf);
 425 typedef bool_t netlink_check_config_fn(void *st, struct buffer_if *buf);
 426 typedef void netlink_set_mtu_fn(void *st, int32_t new_mtu);
 427 struct netlink_if {
 428     void *st;
 429     netlink_register_fn *reg;
 430     netlink_deliver_fn *deliver;
 431     netlink_link_quality_fn *set_quality;
 432     netlink_set_mtu_fn *set_mtu;
 433 };
 434
 435 /* DH interface */
 436
 437 /* Returns public key as a malloced hex string */
 438 typedef string_t dh_makepublic_fn(void *st, uint8_t *secret,
 439                                   int32_t secretlen);
 440 /* Fills buffer (up to buflen) with shared secret */
 441 typedef void dh_makeshared_fn(void *st, uint8_t *secret,
 442                               int32_t secretlen, cstring_t rempublic,
 443                               uint8_t *sharedsecret, int32_t buflen);
 444 struct dh_if {
 445     void *st;
 446     int32_t len; /* Approximate size of modulus in bytes */
 447     dh_makepublic_fn *makepublic;
 448     dh_makeshared_fn *makeshared;
 449 };
 450
 451 /* HASH interface */
 452
 453 typedef void *hash_init_fn(void);
 454 typedef void hash_update_fn(void *st, const void *buf, int32_t len);
 455 typedef void hash_final_fn(void *st, uint8_t *digest);
 456 struct hash_if {
 457     int32_t len; /* Hash output length in bytes */
 458     hash_init_fn *init;
 459     hash_update_fn *update;
 460     hash_final_fn *final;
 461 };
 462
 463 /* BUFFER interface */
 464
 465 struct buffer_if {
 466     bool_t free;
 467     cstring_t owner; /* Set to constant string */
 468     uint32_t flags; /* How paranoid should we be? */
 469     struct cloc loc; /* Where we were defined */
 470     uint8_t *base;
 471     uint8_t *start;
 472     int32_t size; /* Size of buffer contents */
 473     int32_t len; /* Total length allocated at base */
 474 };
 475
 476 /***** LOG functions *****/
 477
 478 #define M_DEBUG_CONFIG 0x001
 479 #define M_DEBUG_PHASE  0x002
 480 #define M_DEBUG        0x004
 481 #define M_INFO         0x008
 482 #define M_NOTICE       0x010
 483 #define M_WARNING      0x020
 484 #define M_ERR          0x040
 485 #define M_SECURITY     0x080
 486 #define M_FATAL        0x100
 487
 488 /* The fatal() family of functions require messages that do not end in '\n' */
 489 extern NORETURN(fatal(const char *message, ...));
 490 extern NORETURN(fatal_perror(const char *message, ...));
 491 extern NORETURN(fatal_status(int status, const char *message, ...));
 492 extern NORETURN(fatal_perror_status(int status, const char *message, ...));
 493
 494 /* The cfgfatal() family of functions require messages that end in '\n' */
 495 extern NORETURN(cfgfatal(struct cloc loc, cstring_t facility,
 496                          const char *message, ...));
 497 extern void cfgfile_postreadcheck(struct cloc loc, FILE *f);
 498 extern NORETURN(vcfgfatal_maybefile(FILE *maybe_f, struct cloc loc,
 499                                     cstring_t facility, const char *message,
 500                                     va_list));
 501 extern NORETURN(cfgfatal_maybefile(FILE *maybe_f, struct cloc loc,
 502                                    cstring_t facility,
 503                                    const char *message, ...));
 504
 505 extern void Message(uint32_t class, const char *message, ...)
 506     FORMAT(printf,2,3);
 507 extern void log_from_fd(int fd, cstring_t prefix, struct log_if *log);
 508
 509 /***** END of log functions *****/
 510
 511 #define STRING2(x) #x
 512 #define STRING(x) STRING2(x)
 513
 514 #define FILLZERO(obj) (memset(&(obj),0,sizeof((obj))))
 515
 516 #endif /* secnet_h */