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