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 #define ADNS_FEATURE_MANYAF
   7
   8 #include "config.h"
   9 #include <stdlib.h>
  10 #include <stdarg.h>
  11 #include <stdio.h>
  12 #include <string.h>
  13 #include <assert.h>
  14 #include <fcntl.h>
  15 #include <unistd.h>
  16 #include <sys/poll.h>
  17 #include <sys/types.h>
  18 #include <sys/time.h>
  19 #include <netinet/in.h>
  20 #include <arpa/inet.h>
  21
  22 #define MAX_PEER_ADDRS 5
  23 /* send at most this many copies; honour at most that many addresses */
  24
  25 struct comm_if;
  26 struct comm_addr;
  27
  28 typedef char *string_t;
  29 typedef const char *cstring_t;
  30
  31 #define False (_Bool)0
  32 #define True  (_Bool)1
  33 typedef _Bool bool_t;
  34
  35 union iaddr {
  36     struct sockaddr sa;
  37     struct sockaddr_in sin;
  38 #ifdef CONFIG_IPV6
  39     struct sockaddr_in6 sin6;
  40 #endif
  41 };
  42
  43 #define ASSERT(x) do { if (!(x)) { fatal("assertion failed line %d file " \
  44                                          __FILE__,__LINE__); } } while(0)
  45
  46 /* from version.c */
  47
  48 extern char version[];
  49
  50 /* from logmsg.c */
  51 extern uint32_t message_level;
  52 extern bool_t secnet_is_daemon;
  53 extern struct log_if *system_log;
  54
  55 /* from process.c */
  56 extern void start_signal_handling(void);
  57
  58 /***** CONFIGURATION support *****/
  59
  60 extern bool_t just_check_config; /* If True then we're going to exit after
  61                                     reading the configuration file */
  62 extern bool_t background; /* If True then we'll eventually run as a daemon */
  63
  64 typedef struct dict dict_t;        /* Configuration dictionary */
  65 typedef struct closure closure_t;
  66 typedef struct item item_t;
  67 typedef struct list list_t;        /* A list of items */
  68
  69 /* Configuration file location, for error-reporting */
  70 struct cloc {
  71     cstring_t file;
  72     int line;
  73 };
  74
  75 /* Modules export closures, which can be invoked from the configuration file.
  76    "Invoking" a closure usually returns another closure (of a different
  77    type), but can actually return any configuration object. */
  78 typedef list_t *(apply_fn)(closure_t *self, struct cloc loc,
  79                            dict_t *context, list_t *data);
  80 struct closure {
  81     cstring_t description; /* For debugging */
  82     uint32_t type; /* Central registry... */
  83     apply_fn *apply;
  84     void *interface; /* Interface for use inside secnet; depends on type */
  85 };
  86
  87 enum types { t_null, t_bool, t_string, t_number, t_dict, t_closure };
  88 struct item {
  89     enum types type;
  90     union {
  91         bool_t bool;
  92         string_t string;
  93         uint32_t number;
  94         dict_t *dict;
  95         closure_t *closure;
  96     } data;
  97     struct cloc loc;
  98 };
  99
 100 /* Note that it is unwise to use this structure directly; use the list
 101    manipulation functions instead. */
 102 struct list {
 103     item_t *item;
 104     struct list *next;
 105 };
 106
 107 /* In the following two lookup functions, NULL means 'not found' */
 108 /* Lookup a value in the specified dictionary, or its parents */
 109 extern list_t *dict_lookup(dict_t *dict, cstring_t key);
 110 /* Lookup a value in just the specified dictionary */
 111 extern list_t *dict_lookup_primitive(dict_t *dict, cstring_t key);
 112 /* Add a value to the specified dictionary */
 113 extern void dict_add(dict_t *dict, cstring_t key, list_t *val);
 114 /* Obtain an array of keys in the dictionary. malloced; caller frees */
 115 extern cstring_t *dict_keys(dict_t *dict);
 116
 117 /* List-manipulation functions */
 118 extern list_t *list_new(void);
 119 extern int32_t list_length(const list_t *a);
 120 extern list_t *list_append(list_t *a, item_t *i);
 121 extern list_t *list_append_list(list_t *a, list_t *b);
 122 /* Returns an item from the list (index starts at 0), or NULL */
 123 extern item_t *list_elem(list_t *l, int32_t index);
 124
 125 /* Convenience functions */
 126 extern list_t *new_closure(closure_t *cl);
 127 extern void add_closure(dict_t *dict, cstring_t name, apply_fn apply);
 128 extern void *find_cl_if(dict_t *dict, cstring_t name, uint32_t type,
 129                         bool_t fail_if_invalid, cstring_t desc,
 130                         struct cloc loc);
 131 extern item_t *dict_find_item(dict_t *dict, cstring_t key, bool_t required,
 132                               cstring_t desc, struct cloc loc);
 133 extern string_t dict_read_string(dict_t *dict, cstring_t key, bool_t required,
 134                                  cstring_t desc, struct cloc loc);
 135 extern uint32_t dict_read_number(dict_t *dict, cstring_t key, bool_t required,
 136                                  cstring_t desc, struct cloc loc,
 137                                  uint32_t def);
 138   /* return value can safely be assigned to int32_t */
 139 extern bool_t dict_read_bool(dict_t *dict, cstring_t key, bool_t required,
 140                              cstring_t desc, struct cloc loc, bool_t def);
 141 struct flagstr {
 142     cstring_t name;
 143     uint32_t value;
 144 };
 145 extern uint32_t string_to_word(cstring_t s, struct cloc loc,
 146                                struct flagstr *f, cstring_t desc);
 147 extern uint32_t string_list_to_word(list_t *l, struct flagstr *f,
 148                                     cstring_t desc);
 149
 150 /***** END of configuration support *****/
 151
 152 /***** UTILITY functions *****/
 153
 154 extern char *safe_strdup(const char *string, const char *message);
 155 extern void *safe_malloc(size_t size, const char *message);
 156 extern void *safe_malloc_ary(size_t size, size_t count, const char *message);
 157
 158 void setcloexec(int fd); /* cannot fail */
 159 void pipe_cloexec(int fd[2]); /* pipe(), setcloexec() twice; cannot fail */
 160
 161 extern int sys_cmd(const char *file, const char *argc, ...);
 162
 163 extern uint64_t now_global;
 164 extern struct timeval tv_now_global;
 165
 166 static const uint64_t       *const now    = &now_global;
 167 static const struct timeval *const tv_now = &tv_now_global;
 168
 169 /* "now" is current program time, in milliseconds. It is derived
 170    from tv_now. Both are provided by the event loop. */
 171
 172 /***** END of utility functions *****/
 173
 174 /***** START of max_start_pad handling *****/
 175
 176 extern int32_t site_max_start_pad, transform_max_start_pad,
 177     comm_max_start_pad;
 178
 179 void update_max_start_pad(int32_t *our_module_global, int32_t our_instance);
 180 int32_t calculate_max_start_pad(void);
 181
 182 /***** END of max_start_pad handling *****/
 183
 184 /***** SCHEDULING support */
 185
 186 /* If nfds_io is insufficient for your needs, set it to the required
 187    number and return ERANGE. timeout is in milliseconds; if it is too
 188    high then lower it. It starts at -1 (==infinite) */
 189 typedef int beforepoll_fn(void *st, struct pollfd *fds, int *nfds_io,
 190                           int *timeout_io);
 191 typedef void afterpoll_fn(void *st, struct pollfd *fds, int nfds);
 192
 193 /* Register interest in the main loop of the program. Before a call
 194    to poll() your supplied beforepoll function will be called. After
 195    the call to poll() the supplied afterpoll function will be called.
 196    max_nfds is a _hint_ about the maximum number of struct pollfd
 197    structures you may require - you can always ask for more in
 198    *nfds_io. */
 199 extern void register_for_poll(void *st, beforepoll_fn *before,
 200                               afterpoll_fn *after, int32_t max_nfds,
 201                               cstring_t desc);
 202
 203 /***** END of scheduling support */
 204
 205 /***** PROGRAM LIFETIME support */
 206
 207 /* The secnet program goes through a number of phases in its lifetime.
 208    Module code may arrange to be called just as various phases are
 209    entered.
 210
 211    Remember to update the table in util.c if changing the set of
 212    phases. */
 213
 214 enum phase {
 215     PHASE_INIT,
 216     PHASE_GETOPTS,             /* Process command-line arguments */
 217     PHASE_READCONFIG,          /* Parse and process configuration file */
 218     PHASE_SETUP,               /* Process information in configuration */
 219     PHASE_DAEMONIZE,           /* Become a daemon (if necessary) */
 220     PHASE_GETRESOURCES,        /* Obtain all external resources */
 221     PHASE_DROPPRIV,            /* Last chance for privileged operations */
 222     PHASE_RUN,
 223     PHASE_SHUTDOWN,            /* About to die; delete key material, etc. */
 224     /* Keep this last: */
 225     NR_PHASES,
 226 };
 227
 228 typedef void hook_fn(void *self, uint32_t newphase);
 229 bool_t add_hook(uint32_t phase, hook_fn *f, void *state);
 230 bool_t remove_hook(uint32_t phase, hook_fn *f, void *state);
 231
 232 extern uint32_t current_phase;
 233 extern void enter_phase(uint32_t new_phase);
 234
 235 /* Some features (like netlink 'soft' routes) require that secnet
 236    retain root privileges.  They should indicate that here when
 237    appropriate. */
 238 extern bool_t require_root_privileges;
 239 extern cstring_t require_root_privileges_explanation;
 240
 241 /***** END of program lifetime support *****/
 242
 243 /***** MODULE support *****/
 244
 245 /* Module initialisation function type - modules export one function of
 246    this type which is called to initialise them. For dynamically loaded
 247    modules it's called "secnet_module". */
 248 typedef void init_module(dict_t *dict);
 249
 250 extern void init_builtin_modules(dict_t *dict);
 251
 252 extern init_module resolver_module;
 253 extern init_module random_module;
 254 extern init_module udp_module;
 255 extern init_module util_module;
 256 extern init_module site_module;
 257 extern init_module transform_eax_module;
 258 extern init_module transform_cbcmac_module;
 259 extern init_module netlink_module;
 260 extern init_module rsa_module;
 261 extern init_module dh_module;
 262 extern init_module md5_module;
 263 extern init_module slip_module;
 264 extern init_module tun_module;
 265 extern init_module sha1_module;
 266 extern init_module log_module;
 267
 268 /***** END of module support *****/
 269
 270 /***** CLOSURE TYPES and interface definitions *****/
 271
 272 #define CL_PURE         0
 273 #define CL_RESOLVER     1
 274 #define CL_RANDOMSRC    2
 275 #define CL_RSAPUBKEY    3
 276 #define CL_RSAPRIVKEY   4
 277 #define CL_COMM         5
 278 #define CL_IPIF         6
 279 #define CL_LOG          7
 280 #define CL_SITE         8
 281 #define CL_TRANSFORM    9
 282 #define CL_DH          11
 283 #define CL_HASH        12
 284 #define CL_BUFFER      13
 285 #define CL_NETLINK     14
 286
 287 struct buffer_if;
 288
 289 /* PURE closure requires no interface */
 290
 291 /* RESOLVER interface */
 292
 293 /* Answers to queries are delivered to a function of this
 294    type. 'address' will be NULL if there was a problem with the query. It
 295    will be freed once resolve_answer_fn returns.  naddrs is the actual
 296    size of the array at addrs; was_naddrs is the number of addresses
 297    actually found in the DNS, which may be bigger if addrs is equal
 298    to MAX_PEER_ADDRS (ie there were too many). */
 299 typedef void resolve_answer_fn(void *st, const struct comm_addr *addrs,
 300                                int naddrs, int was_naddrs,
 301                                const char *failwhy);
 302 typedef bool_t resolve_request_fn(void *st, cstring_t name,
 303                                   int remoteport, struct comm_if *comm,
 304                                   resolve_answer_fn *cb, void *cst);
 305 struct resolver_if {
 306     void *st;
 307     resolve_request_fn *request;
 308 };
 309
 310 /* RANDOMSRC interface */
 311
 312 /* Return some random data. Returns TRUE for success. */
 313 typedef bool_t random_fn(void *st, int32_t bytes, uint8_t *buff);
 314
 315 struct random_if {
 316     void *st;
 317     bool_t blocking;
 318     random_fn *generate;
 319 };
 320
 321 /* RSAPUBKEY interface */
 322
 323 typedef bool_t rsa_checksig_fn(void *st, uint8_t *data, int32_t datalen,
 324                                cstring_t signature);
 325 struct rsapubkey_if {
 326     void *st;
 327     rsa_checksig_fn *check;
 328 };
 329
 330 /* RSAPRIVKEY interface */
 331
 332 typedef string_t rsa_makesig_fn(void *st, uint8_t *data, int32_t datalen);
 333 struct rsaprivkey_if {
 334     void *st;
 335     rsa_makesig_fn *sign;
 336 };
 337
 338 /* COMM interface */
 339
 340 struct comm_addr {
 341     /* This struct is pure data; in particular comm's clients may
 342        freely copy it. */
 343     struct comm_if *comm;
 344     union iaddr ia;
 345     int ix; /* see comment `Re comm_addr.ix' in udp.c */
 346 };
 347
 348 /* Return True if the packet was processed, and shouldn't be passed to
 349    any other potential receivers. */
 350 typedef bool_t comm_notify_fn(void *state, struct buffer_if *buf,
 351                               const struct comm_addr *source);
 352 typedef void comm_request_notify_fn(void *commst, void *nst,
 353                                     comm_notify_fn *fn);
 354 typedef void comm_release_notify_fn(void *commst, void *nst,
 355                                     comm_notify_fn *fn);
 356 typedef bool_t comm_sendmsg_fn(void *commst, struct buffer_if *buf,
 357                                const struct comm_addr *dest);
 358   /* Only returns false if (we know that) the local network
 359    * environment is such that this address cannot work; transient
 360    * or unknown/unexpected failures return true. */
 361 typedef const char *comm_addr_to_string_fn(void *commst,
 362                                            const struct comm_addr *ca);
 363         /* Returned string is in a static buffer. */
 364 struct comm_if {
 365     void *st;
 366     comm_request_notify_fn *request_notify;
 367     comm_release_notify_fn *release_notify;
 368     comm_sendmsg_fn *sendmsg;
 369     comm_addr_to_string_fn *addr_to_string;
 370 };
 371
 372 bool_t iaddr_equal(const union iaddr *ia, const union iaddr *ib);
 373
 374 static inline const char *comm_addr_to_string(const struct comm_addr *ca)
 375 {
 376     return ca->comm->addr_to_string(ca->comm->st, ca);
 377 }
 378
 379 static inline bool_t comm_addr_equal(const struct comm_addr *a,
 380                                      const struct comm_addr *b)
 381 {
 382     return a->comm==b->comm && iaddr_equal(&a->ia,&b->ia);
 383 }
 384
 385 /* LOG interface */
 386
 387 #define LOG_MESSAGE_BUFLEN 1023
 388
 389 typedef void log_msg_fn(void *st, int class, const char *message, ...);
 390 typedef void log_vmsg_fn(void *st, int class, const char *message,
 391                          va_list args);
 392 struct log_if {
 393     void *st;
 394     log_vmsg_fn *vlogfn; /* printf format checking.  Use [v]slilog instead */
 395     char buff[LOG_MESSAGE_BUFLEN+1];
 396 };
 397 /* (convenience functions, defined in util.c) */
 398 extern void slilog(struct log_if *lf, int class, const char *message, ...)
 399 FORMAT(printf,3,4);
 400 extern void vslilog(struct log_if *lf, int class, const char *message, va_list)
 401 FORMAT(printf,3,0);
 402
 403 /* Versions which take (parts of) (multiple) messages, using \n to
 404  * distinguish one message from another. */
 405 extern void slilog_part(struct log_if *lf, int class, const char *message, ...)
 406 FORMAT(printf,3,4);
 407 extern void vslilog_part(struct log_if *lf, int class, const char *message,
 408                          va_list) FORMAT(printf,3,0);
 409
 410 /* SITE interface */
 411
 412 /* Pretty much a placeholder; allows starting and stopping of processing,
 413    key expiry, etc. */
 414 typedef void site_control_fn(void *st, bool_t run);
 415 typedef uint32_t site_status_fn(void *st);
 416 struct site_if {
 417     void *st;
 418     site_control_fn *control;
 419     site_status_fn *status;
 420 };
 421
 422 /* TRANSFORM interface */
 423
 424 /* A reversable transformation. Transforms buffer in-place; may add
 425    data to start or end. (Reverse transformations decrease
 426    length, of course.)  Transformations may be key-dependent, in which
 427    case key material is passed in at initialisation time. They may
 428    also depend on internal factors (eg. time) and keep internal
 429    state. A struct transform_if only represents a particular type of
 430    transformation; instances of the transformation (eg. with
 431    particular key material) have a different C type. The same
 432    secret key will be used in opposite directions between a pair of
 433    secnets; one of these pairs will get direction==False, the other True. */
 434
 435 typedef struct transform_inst_if *transform_createinstance_fn(void *st);
 436 typedef bool_t transform_setkey_fn(void *st, uint8_t *key, int32_t keylen,
 437                                    bool_t direction);
 438 typedef bool_t transform_valid_fn(void *st); /* 0: no key; 1: ok */
 439 typedef void transform_delkey_fn(void *st);
 440 typedef void transform_destroyinstance_fn(void *st);
 441 /* Returns:
 442  *   0: all is well
 443  *   1: for any other problem
 444  *   2: message decrypted but sequence number was out of range
 445  */
 446 typedef uint32_t transform_apply_fn(void *st, struct buffer_if *buf,
 447                                     const char **errmsg);
 448
 449 struct transform_inst_if {
 450     void *st;
 451     transform_setkey_fn *setkey;
 452     transform_valid_fn *valid;
 453     transform_delkey_fn *delkey;
 454     transform_apply_fn *forwards;
 455     transform_apply_fn *reverse;
 456     transform_destroyinstance_fn *destroy;
 457 };
 458
 459 struct transform_if {
 460     void *st;
 461     int capab_transformnum;
 462     int32_t keylen; /* <<< INT_MAX */
 463     transform_createinstance_fn *create;
 464 };
 465
 466 /* NETLINK interface */
 467
 468 /* Used by netlink to deliver to site, and by site to deliver to
 469    netlink.  cid is the client identifier returned by
 470    netlink_regnets_fn.  If buf has size 0 then the function is just
 471    being called for its site-effects (eg. making the site code attempt
 472    to bring up a network link) */
 473 typedef void netlink_deliver_fn(void *st, struct buffer_if *buf);
 474 /* site code can tell netlink when outgoing packets will be dropped,
 475    so netlink can generate appropriate ICMP and make routing decisions */
 476 #define LINK_QUALITY_UNUSED 0   /* This link is unused, do not make this netlink */
 477 #define LINK_QUALITY_DOWN 1   /* No chance of a packet being delivered right away*/
 478 #define LINK_QUALITY_DOWN_STALE_ADDRESS 2 /* Link down, old address information */
 479 #define LINK_QUALITY_DOWN_CURRENT_ADDRESS 3 /* Link down, current address information */
 480 #define LINK_QUALITY_UP 4     /* Link active */
 481 #define MAXIMUM_LINK_QUALITY 3
 482 typedef void netlink_link_quality_fn(void *st, uint32_t quality);
 483 typedef void netlink_register_fn(void *st, netlink_deliver_fn *deliver,
 484                                  void *dst, uint32_t *localmtu_r /* NULL ok */);
 485 typedef void netlink_output_config_fn(void *st, struct buffer_if *buf);
 486 typedef bool_t netlink_check_config_fn(void *st, struct buffer_if *buf);
 487 typedef void netlink_set_mtu_fn(void *st, int32_t new_mtu);
 488 struct netlink_if {
 489     void *st;
 490     netlink_register_fn *reg;
 491     netlink_deliver_fn *deliver;
 492     netlink_link_quality_fn *set_quality;
 493     netlink_set_mtu_fn *set_mtu;
 494 };
 495
 496 /* DH interface */
 497
 498 /* Returns public key as a malloced hex string */
 499 typedef string_t dh_makepublic_fn(void *st, uint8_t *secret,
 500                                   int32_t secretlen);
 501 /* Fills buffer (up to buflen) with shared secret */
 502 typedef void dh_makeshared_fn(void *st, uint8_t *secret,
 503                               int32_t secretlen, cstring_t rempublic,
 504                               uint8_t *sharedsecret, int32_t buflen);
 505 struct dh_if {
 506     void *st;
 507     int32_t len; /* Approximate size of modulus in bytes */
 508     int32_t ceil_len; /* Number of bytes just sufficient to contain modulus */
 509     dh_makepublic_fn *makepublic;
 510     dh_makeshared_fn *makeshared;
 511 };
 512
 513 /* HASH interface */
 514
 515 typedef void *hash_init_fn(void);
 516 typedef void hash_update_fn(void *st, const void *buf, int32_t len);
 517 typedef void hash_final_fn(void *st, uint8_t *digest);
 518 struct hash_if {
 519     int32_t len; /* Hash output length in bytes */
 520     hash_init_fn *init;
 521     hash_update_fn *update;
 522     hash_final_fn *final;
 523 };
 524
 525 /* BUFFER interface */
 526
 527 struct buffer_if {
 528     bool_t free;
 529     cstring_t owner; /* Set to constant string */
 530     uint32_t flags; /* How paranoid should we be? */
 531     struct cloc loc; /* Where we were defined */
 532     uint8_t *base;
 533     uint8_t *start;
 534     int32_t size; /* Size of buffer contents */
 535     int32_t alloclen; /* Total length allocated at base */
 536 };
 537
 538 /***** LOG functions *****/
 539
 540 #define M_DEBUG_CONFIG 0x001
 541 #define M_DEBUG_PHASE  0x002
 542 #define M_DEBUG        0x004
 543 #define M_INFO         0x008
 544 #define M_NOTICE       0x010
 545 #define M_WARNING      0x020
 546 #define M_ERR          0x040
 547 #define M_SECURITY     0x080
 548 #define M_FATAL        0x100
 549
 550 /* The fatal() family of functions require messages that do not end in '\n' */
 551 extern NORETURN(fatal(const char *message, ...)) FORMAT(printf,1,2);
 552 extern NORETURN(fatal_perror(const char *message, ...)) FORMAT(printf,1,2);
 553 extern NORETURN(fatal_status(int status, const char *message, ...))
 554        FORMAT(printf,2,3);
 555 extern NORETURN(fatal_perror_status(int status, const char *message, ...))
 556        FORMAT(printf,2,3);
 557
 558 /* The cfgfatal() family of functions require messages that end in '\n' */
 559 extern NORETURN(cfgfatal(struct cloc loc, cstring_t facility,
 560                          const char *message, ...)) FORMAT(printf,3,4);
 561 extern void cfgfile_postreadcheck(struct cloc loc, FILE *f);
 562 extern NORETURN(vcfgfatal_maybefile(FILE *maybe_f, struct cloc loc,
 563                                     cstring_t facility, const char *message,
 564                                     va_list))
 565     FORMAT(printf,4,0);
 566 extern NORETURN(cfgfatal_maybefile(FILE *maybe_f, struct cloc loc,
 567                                    cstring_t facility,
 568                                    const char *message, ...))
 569     FORMAT(printf,4,5);
 570
 571 extern void Message(uint32_t class, const char *message, ...)
 572     FORMAT(printf,2,3);
 573 extern void log_from_fd(int fd, cstring_t prefix, struct log_if *log);
 574
 575 /***** END of log functions *****/
 576
 577 #define STRING2(x) #x
 578 #define STRING(x) STRING2(x)
 579
 580 #define FILLZERO(obj) (memset(&(obj),0,sizeof((obj))))
 581 #define ARRAY_SIZE(ary) (sizeof((ary))/sizeof((ary)[0]))
 582
 583 /*
 584  * void COPY_OBJ(  OBJECT& dst, const OBJECT& src);
 585  * void COPY_ARRAY(OBJECT *dst, const OBJECT *src, INTEGER count);
 586  *   // Typesafe: we check that the type OBJECT is the same in both cases.
 587  *   // It is OK to use COPY_OBJ on an array object, provided it's
 588  *   // _actually_ the whole array object and not decayed into a
 589  *   // pointer (e.g. a formal parameter).
 590  */
 591 #define COPY_OBJ(dst,src) \
 592     (&(dst)==&(src), memcpy(&(dst),&(src),sizeof((dst))))
 593 #define COPY_ARRAY(dst,src,count) \
 594     (&(dst)[0]==&(src)[0], memcpy((dst),(src),sizeof((dst)[0])*(count)))
 595
 596 #endif /* secnet_h */