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 <string.h>
  11 #include <assert.h>
  12 #include <fcntl.h>
  13 #include <unistd.h>
  14 #include <sys/poll.h>
  15 #include <sys/types.h>
  16 #include <sys/time.h>
  17 #include <netinet/in.h>
  18
  19 typedef char *string_t;
  20 typedef const char *cstring_t;
  21
  22 #define False (_Bool)0
  23 #define True  (_Bool)1
  24 typedef _Bool bool_t;
  25
  26 #define ASSERT(x) do { if (!(x)) { fatal("assertion failed line %d file " \
  27                                          __FILE__,__LINE__); } } while(0)
  28
  29 /* from version.c */
  30
  31 extern char version[];
  32
  33 /* from logmsg.c */
  34 extern uint32_t message_level;
  35 extern bool_t secnet_is_daemon;
  36 extern struct log_if *system_log;
  37
  38 /* from process.c */
  39 extern void start_signal_handling(void);
  40
  41 /***** CONFIGURATION support *****/
  42
  43 extern bool_t just_check_config; /* If True then we're going to exit after
  44                                     reading the configuration file */
  45 extern bool_t background; /* If True then we'll eventually run as a daemon */
  46
  47 typedef struct dict dict_t;        /* Configuration dictionary */
  48 typedef struct closure closure_t;
  49 typedef struct item item_t;
  50 typedef struct list list_t;        /* A list of items */
  51
  52 /* Configuration file location, for error-reporting */
  53 struct cloc {
  54     cstring_t file;
  55     int line;
  56 };
  57
  58 /* Modules export closures, which can be invoked from the configuration file.
  59    "Invoking" a closure usually returns another closure (of a different
  60    type), but can actually return any configuration object. */
  61 typedef list_t *(apply_fn)(closure_t *self, struct cloc loc,
  62                            dict_t *context, list_t *data);
  63 struct closure {
  64     cstring_t description; /* For debugging */
  65     uint32_t type; /* Central registry... */
  66     apply_fn *apply;
  67     void *interface; /* Interface for use inside secnet; depends on type */
  68 };
  69
  70 enum types { t_null, t_bool, t_string, t_number, t_dict, t_closure };
  71 struct item {
  72     enum types type;
  73     union {
  74         bool_t bool;
  75         string_t string;
  76         uint32_t number;
  77         dict_t *dict;
  78         closure_t *closure;
  79     } data;
  80     struct cloc loc;
  81 };
  82
  83 /* Note that it is unwise to use this structure directly; use the list
  84    manipulation functions instead. */
  85 struct list {
  86     item_t *item;
  87     struct list *next;
  88 };
  89
  90 /* In the following two lookup functions, NULL means 'not found' */
  91 /* Lookup a value in the specified dictionary, or its parents */
  92 extern list_t *dict_lookup(dict_t *dict, cstring_t key);
  93 /* Lookup a value in just the specified dictionary */
  94 extern list_t *dict_lookup_primitive(dict_t *dict, cstring_t key);
  95 /* Add a value to the specified dictionary */
  96 extern void dict_add(dict_t *dict, cstring_t key, list_t *val);
  97 /* Obtain an array of keys in the dictionary. malloced; caller frees */
  98 extern cstring_t *dict_keys(dict_t *dict);
  99
 100 /* List-manipulation functions */
 101 extern list_t *list_new(void);
 102 extern int32_t list_length(list_t *a);
 103 extern list_t *list_append(list_t *a, item_t *i);
 104 extern list_t *list_append_list(list_t *a, list_t *b);
 105 /* Returns an item from the list (index starts at 0), or NULL */
 106 extern item_t *list_elem(list_t *l, int32_t index);
 107
 108 /* Convenience functions */
 109 extern list_t *new_closure(closure_t *cl);
 110 extern void add_closure(dict_t *dict, cstring_t name, apply_fn apply);
 111 extern void *find_cl_if(dict_t *dict, cstring_t name, uint32_t type,
 112                         bool_t fail_if_invalid, cstring_t desc,
 113                         struct cloc loc);
 114 extern item_t *dict_find_item(dict_t *dict, cstring_t key, bool_t required,
 115                               cstring_t desc, struct cloc loc);
 116 extern string_t dict_read_string(dict_t *dict, cstring_t key, bool_t required,
 117                                  cstring_t desc, struct cloc loc);
 118 extern uint32_t dict_read_number(dict_t *dict, cstring_t key, bool_t required,
 119                                  cstring_t desc, struct cloc loc,
 120                                  uint32_t def);
 121   /* return value can safely be assigned to int32_t */
 122 extern bool_t dict_read_bool(dict_t *dict, cstring_t key, bool_t required,
 123                              cstring_t desc, struct cloc loc, bool_t def);
 124 struct flagstr {
 125     cstring_t name;
 126     uint32_t value;
 127 };
 128 extern uint32_t string_to_word(cstring_t s, struct cloc loc,
 129                                struct flagstr *f, cstring_t desc);
 130 extern uint32_t string_list_to_word(list_t *l, struct flagstr *f,
 131                                     cstring_t desc);
 132
 133 /***** END of configuration support *****/
 134
 135 /***** UTILITY functions *****/
 136
 137 extern char *safe_strdup(const char *string, const char *message);
 138 extern void *safe_malloc(size_t size, const char *message);
 139 extern void *safe_malloc_ary(size_t size, size_t count, const char *message);
 140
 141 void setcloexec(int fd); /* cannot fail */
 142
 143 extern int sys_cmd(const char *file, const char *argc, ...);
 144
 145 extern uint64_t now_global;
 146 extern struct timeval tv_now_global;
 147
 148 static const uint64_t       *const now    = &now_global;
 149 static const struct timeval *const tv_now = &tv_now_global;
 150
 151 /* "now" is current program time, in milliseconds. It is derived
 152    from tv_now. Both are provided by the event loop. */
 153
 154 /***** END of utility functions *****/
 155
 156 /***** START of max_start_pad handling *****/
 157
 158 extern int32_t site_max_start_pad, transform_max_start_pad,
 159     comm_max_start_pad;
 160
 161 void update_max_start_pad(int32_t *our_module_global, int32_t our_instance);
 162 int32_t calculate_max_start_pad(void);
 163
 164 /***** END of max_start_pad handling *****/
 165
 166 /***** SCHEDULING support */
 167
 168 /* If nfds_io is insufficient for your needs, set it to the required
 169    number and return ERANGE. timeout is in milliseconds; if it is too
 170    high then lower it. It starts at -1 (==infinite) */
 171 typedef int beforepoll_fn(void *st, struct pollfd *fds, int *nfds_io,
 172                           int *timeout_io);
 173 typedef void afterpoll_fn(void *st, struct pollfd *fds, int nfds);
 174
 175 /* Register interest in the main loop of the program. Before a call
 176    to poll() your supplied beforepoll function will be called. After
 177    the call to poll() the supplied afterpoll function will be called.
 178    max_nfds is a _hint_ about the maximum number of struct pollfd
 179    structures you may require - you can always ask for more in
 180    *nfds_io. */
 181 extern void register_for_poll(void *st, beforepoll_fn *before,
 182                               afterpoll_fn *after, int32_t max_nfds,
 183                               cstring_t desc);
 184
 185 /***** END of scheduling support */
 186
 187 /***** PROGRAM LIFETIME support */
 188
 189 /* The secnet program goes through a number of phases in its lifetime.
 190    Module code may arrange to be called just as various phases are
 191    entered.
 192
 193    Remember to update the table in util.c if changing the set of
 194    phases. */
 195
 196 enum phase {
 197     PHASE_INIT,
 198     PHASE_GETOPTS,             /* Process command-line arguments */
 199     PHASE_READCONFIG,          /* Parse and process configuration file */
 200     PHASE_SETUP,               /* Process information in configuration */
 201     PHASE_DAEMONIZE,           /* Become a daemon (if necessary) */
 202     PHASE_GETRESOURCES,        /* Obtain all external resources */
 203     PHASE_DROPPRIV,            /* Last chance for privileged operations */
 204     PHASE_RUN,
 205     PHASE_SHUTDOWN,            /* About to die; delete key material, etc. */
 206     /* Keep this last: */
 207     NR_PHASES,
 208 };
 209
 210 typedef void hook_fn(void *self, uint32_t newphase);
 211 bool_t add_hook(uint32_t phase, hook_fn *f, void *state);
 212 bool_t remove_hook(uint32_t phase, hook_fn *f, void *state);
 213
 214 extern uint32_t current_phase;
 215 extern void enter_phase(uint32_t new_phase);
 216
 217 /* Some features (like netlink 'soft' routes) require that secnet
 218    retain root privileges.  They should indicate that here when
 219    appropriate. */
 220 extern bool_t require_root_privileges;
 221 extern cstring_t require_root_privileges_explanation;
 222
 223 /***** END of program lifetime support *****/
 224
 225 /***** MODULE support *****/
 226
 227 /* Module initialisation function type - modules export one function of
 228    this type which is called to initialise them. For dynamically loaded
 229    modules it's called "secnet_module". */
 230 typedef void init_module(dict_t *dict);
 231
 232 extern void init_builtin_modules(dict_t *dict);
 233
 234 extern init_module resolver_module;
 235 extern init_module random_module;
 236 extern init_module udp_module;
 237 extern init_module util_module;
 238 extern init_module site_module;
 239 extern init_module transform_eax_module;
 240 extern init_module transform_cbcmac_module;
 241 extern init_module netlink_module;
 242 extern init_module rsa_module;
 243 extern init_module dh_module;
 244 extern init_module md5_module;
 245 extern init_module slip_module;
 246 extern init_module tun_module;
 247 extern init_module sha1_module;
 248 extern init_module log_module;
 249
 250 /***** END of module support *****/
 251
 252 /***** CLOSURE TYPES and interface definitions *****/
 253
 254 #define CL_PURE         0
 255 #define CL_RESOLVER     1
 256 #define CL_RANDOMSRC    2
 257 #define CL_RSAPUBKEY    3
 258 #define CL_RSAPRIVKEY   4
 259 #define CL_COMM         5
 260 #define CL_IPIF         6
 261 #define CL_LOG          7
 262 #define CL_SITE         8
 263 #define CL_TRANSFORM    9
 264 #define CL_DH          11
 265 #define CL_HASH        12
 266 #define CL_BUFFER      13
 267 #define CL_NETLINK     14
 268
 269 struct buffer_if;
 270
 271 /* PURE closure requires no interface */
 272
 273 /* RESOLVER interface */
 274
 275 /* Answers to queries are delivered to a function of this
 276    type. 'address' will be NULL if there was a problem with the query. It
 277    will be freed once resolve_answer_fn returns. It is in network byte
 278    order. */
 279 /* XXX extend to be able to provide multiple answers */
 280 typedef void resolve_answer_fn(void *st, struct in_addr *addr);
 281 typedef bool_t resolve_request_fn(void *st, cstring_t name,
 282                                   resolve_answer_fn *cb, void *cst);
 283 struct resolver_if {
 284     void *st;
 285     resolve_request_fn *request;
 286 };
 287
 288 /* RANDOMSRC interface */
 289
 290 /* Return some random data. Returns TRUE for success. */
 291 typedef bool_t random_fn(void *st, int32_t bytes, uint8_t *buff);
 292
 293 struct random_if {
 294     void *st;
 295     bool_t blocking;
 296     random_fn *generate;
 297 };
 298
 299 /* RSAPUBKEY interface */
 300
 301 typedef bool_t rsa_checksig_fn(void *st, uint8_t *data, int32_t datalen,
 302                                cstring_t signature);
 303 struct rsapubkey_if {
 304     void *st;
 305     rsa_checksig_fn *check;
 306 };
 307
 308 /* RSAPRIVKEY interface */
 309
 310 typedef string_t rsa_makesig_fn(void *st, uint8_t *data, int32_t datalen);
 311 struct rsaprivkey_if {
 312     void *st;
 313     rsa_makesig_fn *sign;
 314 };
 315
 316 /* COMM interface */
 317
 318 struct comm_addr {
 319     /* This struct is pure data; in particular comm's clients may
 320        freely copy it. */
 321     /* Everyone is also guaranteed that all padding is set to zero, ie
 322        that comm_addrs referring to semantically identical peers will
 323        compare equal with memcmp.  Anyone who constructs a comm_addr
 324        must start by memsetting it with FILLZERO, or some
 325        equivalent. */
 326     struct comm_if *comm;
 327     struct sockaddr_in sin;
 328 };
 329
 330 /* Return True if the packet was processed, and shouldn't be passed to
 331    any other potential receivers. */
 332 typedef bool_t comm_notify_fn(void *state, struct buffer_if *buf,
 333                               const struct comm_addr *source);
 334 typedef void comm_request_notify_fn(void *commst, void *nst,
 335                                     comm_notify_fn *fn);
 336 typedef void comm_release_notify_fn(void *commst, void *nst,
 337                                     comm_notify_fn *fn);
 338 typedef bool_t comm_sendmsg_fn(void *commst, struct buffer_if *buf,
 339                                const struct comm_addr *dest);
 340 typedef const char *comm_addr_to_string_fn(void *commst,
 341                                            const struct comm_addr *ca);
 342         /* Returned string is in a static buffer. */
 343 struct comm_if {
 344     void *st;
 345     comm_request_notify_fn *request_notify;
 346     comm_release_notify_fn *release_notify;
 347     comm_sendmsg_fn *sendmsg;
 348     comm_addr_to_string_fn *addr_to_string;
 349 };
 350
 351 static inline const char *comm_addr_to_string(const struct comm_addr *ca)
 352 {
 353     return ca->comm->addr_to_string(ca->comm->st, ca);
 354 }
 355
 356 /* LOG interface */
 357
 358 #define LOG_MESSAGE_BUFLEN 1023
 359
 360 typedef void log_msg_fn(void *st, int class, const char *message, ...);
 361 typedef void log_vmsg_fn(void *st, int class, const char *message,
 362                          va_list args);
 363 struct log_if {
 364     void *st;
 365     log_vmsg_fn *vlogfn; /* printf format checking.  Use [v]slilog instead */
 366     char buff[LOG_MESSAGE_BUFLEN+1];
 367 };
 368 /* (convenience functions, defined in util.c) */
 369 extern void slilog(struct log_if *lf, int class, const char *message, ...)
 370 FORMAT(printf,3,4);
 371 extern void vslilog(struct log_if *lf, int class, const char *message, va_list)
 372 FORMAT(printf,3,0);
 373
 374 /* Versions which take (parts of) (multiple) messages, using \n to
 375  * distinguish one message from another. */
 376 extern void slilog_part(struct log_if *lf, int class, const char *message, ...)
 377 FORMAT(printf,3,4);
 378 extern void vslilog_part(struct log_if *lf, int class, const char *message,
 379                          va_list) FORMAT(printf,3,0);
 380
 381 /* SITE interface */
 382
 383 /* Pretty much a placeholder; allows starting and stopping of processing,
 384    key expiry, etc. */
 385 typedef void site_control_fn(void *st, bool_t run);
 386 typedef uint32_t site_status_fn(void *st);
 387 struct site_if {
 388     void *st;
 389     site_control_fn *control;
 390     site_status_fn *status;
 391 };
 392
 393 /* TRANSFORM interface */
 394
 395 /* A reversable transformation. Transforms buffer in-place; may add
 396    data to start or end. (Reverse transformations decrease
 397    length, of course.)  Transformations may be key-dependent, in which
 398    case key material is passed in at initialisation time. They may
 399    also depend on internal factors (eg. time) and keep internal
 400    state. A struct transform_if only represents a particular type of
 401    transformation; instances of the transformation (eg. with
 402    particular key material) have a different C type. The same
 403    secret key will be used in opposite directions between a pair of
 404    secnets; one of these pairs will get direction==False, the other True. */
 405
 406 typedef struct transform_inst_if *transform_createinstance_fn(void *st);
 407 typedef bool_t transform_setkey_fn(void *st, uint8_t *key, int32_t keylen,
 408                                    bool_t direction);
 409 typedef bool_t transform_valid_fn(void *st); /* 0: no key; 1: ok */
 410 typedef void transform_delkey_fn(void *st);
 411 typedef void transform_destroyinstance_fn(void *st);
 412 /* Returns:
 413  *   0: all is well
 414  *   1: for any other problem
 415  *   2: message decrypted but sequence number was out of range
 416  */
 417 typedef uint32_t transform_apply_fn(void *st, struct buffer_if *buf,
 418                                     const char **errmsg);
 419
 420 struct transform_inst_if {
 421     void *st;
 422     transform_setkey_fn *setkey;
 423     transform_valid_fn *valid;
 424     transform_delkey_fn *delkey;
 425     transform_apply_fn *forwards;
 426     transform_apply_fn *reverse;
 427     transform_destroyinstance_fn *destroy;
 428 };
 429
 430 struct transform_if {
 431     void *st;
 432     int capab_transformnum;
 433     int32_t keylen; /* <<< INT_MAX */
 434     transform_createinstance_fn *create;
 435 };
 436
 437 /* NETLINK interface */
 438
 439 /* Used by netlink to deliver to site, and by site to deliver to
 440    netlink.  cid is the client identifier returned by
 441    netlink_regnets_fn.  If buf has size 0 then the function is just
 442    being called for its site-effects (eg. making the site code attempt
 443    to bring up a network link) */
 444 typedef void netlink_deliver_fn(void *st, struct buffer_if *buf);
 445 /* site code can tell netlink when outgoing packets will be dropped,
 446    so netlink can generate appropriate ICMP and make routing decisions */
 447 #define LINK_QUALITY_UNUSED 0   /* This link is unused, do not make this netlink */
 448 #define LINK_QUALITY_DOWN 1   /* No chance of a packet being delivered right away*/
 449 #define LINK_QUALITY_DOWN_STALE_ADDRESS 2 /* Link down, old address information */
 450 #define LINK_QUALITY_DOWN_CURRENT_ADDRESS 3 /* Link down, current address information */
 451 #define LINK_QUALITY_UP 4     /* Link active */
 452 #define MAXIMUM_LINK_QUALITY 3
 453 typedef void netlink_link_quality_fn(void *st, uint32_t quality);
 454 typedef void netlink_register_fn(void *st, netlink_deliver_fn *deliver,
 455                                  void *dst, uint32_t *localmtu_r /* NULL ok */);
 456 typedef void netlink_output_config_fn(void *st, struct buffer_if *buf);
 457 typedef bool_t netlink_check_config_fn(void *st, struct buffer_if *buf);
 458 typedef void netlink_set_mtu_fn(void *st, int32_t new_mtu);
 459 struct netlink_if {
 460     void *st;
 461     netlink_register_fn *reg;
 462     netlink_deliver_fn *deliver;
 463     netlink_link_quality_fn *set_quality;
 464     netlink_set_mtu_fn *set_mtu;
 465 };
 466
 467 /* DH interface */
 468
 469 /* Returns public key as a malloced hex string */
 470 typedef string_t dh_makepublic_fn(void *st, uint8_t *secret,
 471                                   int32_t secretlen);
 472 /* Fills buffer (up to buflen) with shared secret */
 473 typedef void dh_makeshared_fn(void *st, uint8_t *secret,
 474                               int32_t secretlen, cstring_t rempublic,
 475                               uint8_t *sharedsecret, int32_t buflen);
 476 struct dh_if {
 477     void *st;
 478     int32_t len; /* Approximate size of modulus in bytes */
 479     int32_t ceil_len; /* Number of bytes just sufficient to contain modulus */
 480     dh_makepublic_fn *makepublic;
 481     dh_makeshared_fn *makeshared;
 482 };
 483
 484 /* HASH interface */
 485
 486 typedef void *hash_init_fn(void);
 487 typedef void hash_update_fn(void *st, const void *buf, int32_t len);
 488 typedef void hash_final_fn(void *st, uint8_t *digest);
 489 struct hash_if {
 490     int32_t len; /* Hash output length in bytes */
 491     hash_init_fn *init;
 492     hash_update_fn *update;
 493     hash_final_fn *final;
 494 };
 495
 496 /* BUFFER interface */
 497
 498 struct buffer_if {
 499     bool_t free;
 500     cstring_t owner; /* Set to constant string */
 501     uint32_t flags; /* How paranoid should we be? */
 502     struct cloc loc; /* Where we were defined */
 503     uint8_t *base;
 504     uint8_t *start;
 505     int32_t size; /* Size of buffer contents */
 506     int32_t alloclen; /* Total length allocated at base */
 507 };
 508
 509 /***** LOG functions *****/
 510
 511 #define M_DEBUG_CONFIG 0x001
 512 #define M_DEBUG_PHASE  0x002
 513 #define M_DEBUG        0x004
 514 #define M_INFO         0x008
 515 #define M_NOTICE       0x010
 516 #define M_WARNING      0x020
 517 #define M_ERR          0x040
 518 #define M_SECURITY     0x080
 519 #define M_FATAL        0x100
 520
 521 /* The fatal() family of functions require messages that do not end in '\n' */
 522 extern NORETURN(fatal(const char *message, ...)) FORMAT(printf,1,2);
 523 extern NORETURN(fatal_perror(const char *message, ...)) FORMAT(printf,1,2);
 524 extern NORETURN(fatal_status(int status, const char *message, ...))
 525        FORMAT(printf,2,3);
 526 extern NORETURN(fatal_perror_status(int status, const char *message, ...))
 527        FORMAT(printf,2,3);
 528
 529 /* The cfgfatal() family of functions require messages that end in '\n' */
 530 extern NORETURN(cfgfatal(struct cloc loc, cstring_t facility,
 531                          const char *message, ...)) FORMAT(printf,3,4);
 532 extern void cfgfile_postreadcheck(struct cloc loc, FILE *f);
 533 extern NORETURN(vcfgfatal_maybefile(FILE *maybe_f, struct cloc loc,
 534                                     cstring_t facility, const char *message,
 535                                     va_list))
 536     FORMAT(printf,4,0);
 537 extern NORETURN(cfgfatal_maybefile(FILE *maybe_f, struct cloc loc,
 538                                    cstring_t facility,
 539                                    const char *message, ...))
 540     FORMAT(printf,4,5);
 541
 542 extern void Message(uint32_t class, const char *message, ...)
 543     FORMAT(printf,2,3);
 544 extern void log_from_fd(int fd, cstring_t prefix, struct log_if *log);
 545
 546 /***** END of log functions *****/
 547
 548 #define STRING2(x) #x
 549 #define STRING(x) STRING2(x)
 550
 551 #define FILLZERO(obj) (memset(&(obj),0,sizeof((obj))))
 552
 553 #endif /* secnet_h */