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 <sys/poll.h>
  10 #include <sys/types.h>
  11 #include <sys/time.h>
  12 #include <netinet/in.h>
  13
  14 typedef char *string_t;
  15 typedef enum {False,True} bool_t;
  16
  17 #define ASSERT(x) do { if (!(x)) { fatal("assertion failed line " __LINE__ \
  18                                          " file " __FILE__ "\n"); } while(0)
  19
  20 /***** SHARED types *****/
  21
  22 /* These are stored in HOST byte order */
  23 struct subnet {
  24     uint32_t prefix;
  25     uint32_t mask;
  26     uint32_t len;
  27 };
  28
  29 struct subnet_list {
  30     uint32_t entries;
  31     struct subnet *list;
  32 };
  33
  34 /* Match an address (in HOST byte order) with a subnet list.
  35    Returns True if matched. */
  36 extern bool_t subnet_match(struct subnet *s, uint32_t address);
  37 extern bool_t subnet_matches_list(struct subnet_list *list, uint32_t address);
  38 extern bool_t subnets_intersect(struct subnet a, struct subnet b);
  39 extern bool_t subnet_intersects_with_list(struct subnet a,
  40                                           struct subnet_list *b);
  41 extern bool_t subnet_lists_intersect(struct subnet_list *a,
  42                                      struct subnet_list *b);
  43
  44 /***** END of shared types *****/
  45
  46 /***** CONFIGURATION support *****/
  47
  48 extern bool_t just_check_config; /* If True then we're going to exit after
  49                                     reading the configuration file */
  50 extern bool_t background; /* If True then we'll eventually run as a daemon */
  51
  52 typedef struct dict dict_t;        /* Configuration dictionary */
  53 typedef struct closure closure_t;
  54 typedef struct item item_t;
  55 typedef struct list list_t;        /* A list of items */
  56
  57 /* Configuration file location, for error-reporting */
  58 struct cloc {
  59     string_t file;
  60     uint32_t line;
  61 };
  62
  63 /* Modules export closures, which can be invoked from the configuration file.
  64    "Invoking" a closure usually returns another closure (of a different
  65    type), but can actually return any configuration object. */
  66 typedef list_t *(apply_fn)(closure_t *self, struct cloc loc,
  67                            dict_t *context, list_t *data);
  68 struct closure {
  69     string_t description; /* For debugging */
  70     uint32_t type; /* Central registry... */
  71     apply_fn *apply;
  72     void *interface; /* Interface for use inside secnet; depends on type */
  73 };
  74
  75 enum types { t_null, t_bool, t_string, t_number, t_dict, t_closure };
  76 struct item {
  77     enum types type;
  78     union {
  79         bool_t bool;
  80         string_t string;
  81         uint32_t number;
  82         dict_t *dict;
  83         closure_t *closure;
  84     } data;
  85     struct cloc loc;
  86 };
  87
  88 struct list {
  89     item_t *item;
  90     struct list *next;
  91 };
  92
  93 /* In the following two lookup functions, NULL means 'not found' */
  94 /* Lookup a value in the specified dictionary, or its parents */
  95 extern list_t *dict_lookup(dict_t *dict, string_t key);
  96 /* Lookup a value in just the specified dictionary */
  97 extern list_t *dict_lookup_primitive(dict_t *dict, string_t key);
  98 /* Add a value to the specified dictionary */
  99 extern void dict_add(dict_t *dict, string_t key, list_t *val);
 100 /* Obtain an array of keys in the dictionary. malloced; caller frees */
 101 extern string_t *dict_keys(dict_t *dict);
 102
 103 /* List-manipulation functions */
 104 extern list_t *list_new(void);
 105 extern uint32_t list_length(list_t *a);
 106 extern list_t *list_append(list_t *a, item_t *i);
 107 extern list_t *list_append_list(list_t *a, list_t *b);
 108 /* Returns an item from the list (index starts at 0), or NULL */
 109 extern item_t *list_elem(list_t *l, uint32_t index);
 110
 111 /* Convenience functions */
 112 extern list_t *new_closure(closure_t *cl);
 113 extern void add_closure(dict_t *dict, string_t name, apply_fn apply);
 114 extern void *find_cl_if(dict_t *dict, string_t name, uint32_t type,
 115                         bool_t fail_if_invalid, string_t desc,
 116                         struct cloc loc);
 117 extern item_t *dict_find_item(dict_t *dict, string_t key, bool_t required,
 118                               string_t desc, struct cloc loc);
 119 extern string_t dict_read_string(dict_t *dict, string_t key, bool_t required,
 120                                  string_t desc, struct cloc loc);
 121 extern uint32_t dict_read_number(dict_t *dict, string_t key, bool_t required,
 122                                  string_t desc, struct cloc loc, uint32_t def);
 123 extern bool_t dict_read_bool(dict_t *dict, string_t key, bool_t required,
 124                              string_t desc, struct cloc loc, bool_t def);
 125 extern void dict_read_subnet_list(dict_t *dict, string_t key, bool_t required,
 126                                   string_t desc, struct cloc loc,
 127                                   struct subnet_list *sl);
 128 extern uint32_t string_to_ipaddr(item_t *i, string_t desc);
 129 struct flagstr {
 130     string_t name;
 131     uint32_t value;
 132 };
 133 extern uint32_t string_to_word(string_t s, struct cloc loc,
 134                                struct flagstr *f, string_t desc);
 135 extern uint32_t string_list_to_word(list_t *l, struct flagstr *f,
 136                                     string_t desc);
 137
 138 /***** END of configuration support *****/
 139
 140 /***** UTILITY functions *****/
 141
 142 #define M_DEBUG_CONFIG 0x001
 143 #define M_DEBUG_PHASE  0x002
 144 #define M_DEBUG        0x004
 145 #define M_INFO         0x008
 146 #define M_NOTICE       0x010
 147 #define M_WARNING      0x020
 148 #define M_ERROR        0x040
 149 #define M_SECURITY     0x080
 150 #define M_FATAL        0x100
 151
 152 extern void fatal(char *message, ...);
 153 extern void fatal_perror(char *message, ...);
 154 extern void fatal_status(int status, char *message, ...);
 155 extern void fatal_perror_status(int status, char *message, ...);
 156 extern void cfgfatal(struct cloc loc, string_t facility, char *message, ...);
 157
 158 extern char *safe_strdup(char *string, char *message);
 159 extern void *safe_malloc(size_t size, char *message);
 160
 161 extern void Message(uint32_t class, char *message, ...);
 162
 163 extern string_t ipaddr_to_string(uint32_t addr);
 164 extern string_t subnet_to_string(struct subnet *sn);
 165
 166 extern int sys_cmd(const char *file, char *argc, ...);
 167
 168 /***** END of utility functions *****/
 169
 170 /***** SCHEDULING support */
 171
 172 /* "now" is current program time, in milliseconds. It is derived
 173    (once) from tv_now. If nfds_io is insufficient for your needs, set
 174    it to the required number and return ERANGE. timeout is in milliseconds;
 175    if it is too high then lower it. It starts at -1 (==infinite) */
 176 typedef int beforepoll_fn(void *st, struct pollfd *fds, int *nfds_io,
 177                           int *timeout_io, const struct timeval *tv_now,
 178                           uint64_t *now);
 179 typedef void afterpoll_fn(void *st, struct pollfd *fds, int nfds,
 180                           const struct timeval *tv_now, uint64_t *now);
 181
 182 /* Register interest in the main loop of the program. Before a call
 183    to poll() your supplied beforepoll function will be called. After
 184    the call to poll() the supplied afterpoll function will be called.
 185    max_nfds is a _hint_ about the maximum number of struct pollfd
 186    structures you may require - you can always ask for more in
 187    *nfds_io. */
 188 extern void register_for_poll(void *st, beforepoll_fn *before,
 189                               afterpoll_fn *after, uint32_t max_nfds,
 190                               string_t desc);
 191
 192 /***** END of scheduling support */
 193
 194 /***** PROGRAM LIFETIME support */
 195
 196 /* The secnet program goes through a number of phases in its lifetime.
 197    Module code may arrange to be called just as various phases are
 198    entered. */
 199
 200 #define PHASE_INIT          0
 201 #define PHASE_GETOPTS       1  /* Process command-line arguments */
 202 #define PHASE_READCONFIG    2  /* Parse and process configuration file */
 203 #define PHASE_SETUP         3  /* Process information in configuration */
 204 #define PHASE_GETRESOURCES  4  /* Obtain all external resources */
 205 #define PHASE_DROPPRIV      5  /* Last chance for privileged operations */
 206 #define PHASE_RUN           6
 207 #define PHASE_SHUTDOWN      7  /* About to die; delete key material, etc. */
 208 #define NR_PHASES           8
 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 bool_t require_root_privileges; /* Some features (like netlink
 215                                           'soft' routes) require that
 216                                           secnet retain root
 217                                           privileges.  They should
 218                                           indicate that here when
 219                                           appropriate. */
 220 extern string_t require_root_privileges_explanation;
 221
 222 /***** END of program lifetime support *****/
 223
 224 /***** MODULE support *****/
 225
 226 /* Module initialisation function type - modules export one function of
 227    this type which is called to initialise them. For dynamically loaded
 228    modules it's called "secnet_module". */
 229 typedef void (init_module)(dict_t *dict);
 230
 231 /***** END of module support *****/
 232
 233 /***** CLOSURE TYPES and interface definitions *****/
 234
 235 #define CL_PURE        0
 236 #define CL_RESOLVER    1
 237 #define CL_RANDOMSRC   2
 238 #define CL_RSAPUBKEY   3
 239 #define CL_RSAPRIVKEY  4
 240 #define CL_COMM        5
 241 #define CL_IPIF        6
 242 #define CL_LOG         7
 243 #define CL_SITE        8
 244 #define CL_TRANSFORM   9
 245 #define CL_NETLINK    10
 246 #define CL_DH         11
 247 #define CL_HASH       12
 248 #define CL_BUFFER     13
 249
 250 struct buffer_if;
 251
 252 /* PURE closure requires no interface */
 253
 254 /* RESOLVER interface */
 255
 256 /* Answers to queries are delivered to a function of this
 257    type. 'address' will be NULL if there was a problem with the query. It
 258    will be freed once resolve_answer_fn returns. It is in network byte
 259    order. */
 260 typedef void resolve_answer_fn(void *st, struct in_addr *addr);
 261 typedef bool_t resolve_request_fn(void *st, string_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, uint32_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, uint32_t datalen,
 282                                string_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, uint32_t datalen);
 291 struct rsaprivkey_if {
 292     void *st;
 293     rsa_makesig_fn *sign;
 294 };
 295
 296 /* COMM interface */
 297
 298 /* Return True if the packet was processed, and shouldn't be passed to
 299    any other potential receivers. */
 300 typedef bool_t comm_notify_fn(void *state, struct buffer_if *buf,
 301                             struct sockaddr_in *source);
 302 typedef void comm_request_notify_fn(void *commst, void *nst,
 303                                     comm_notify_fn *fn);
 304 typedef void comm_release_notify_fn(void *commst, void *nst,
 305                                     comm_notify_fn *fn);
 306 typedef bool_t comm_sendmsg_fn(void *commst, struct buffer_if *buf,
 307                                struct sockaddr_in *dest);
 308 struct comm_if {
 309     void *st;
 310     comm_request_notify_fn *request_notify;
 311     comm_release_notify_fn *release_notify;
 312     comm_sendmsg_fn *sendmsg;
 313 };
 314
 315 /* LOG interface */
 316
 317 typedef void log_msg_fn(void *st, int class, char *message, ...);
 318 typedef void log_vmsg_fn(void *st, int class, char *message, va_list args);
 319 struct log_if {
 320     void *st;
 321     log_msg_fn *log;
 322     log_vmsg_fn *vlog;
 323 };
 324 /* (convenience function, defined in util.c) */
 325 extern void log(struct log_if *lf, int class, char *message, ...);
 326
 327 /* SITE interface */
 328
 329 /* Pretty much a placeholder; allows starting and stopping of processing,
 330    key expiry, etc. */
 331 typedef void site_control_fn(void *st, bool_t run);
 332 typedef uint32_t site_status_fn(void *st);
 333 struct site_if {
 334     void *st;
 335     site_control_fn *control;
 336     site_status_fn *status;
 337 };
 338
 339 /* TRANSFORM interface */
 340
 341 /* A reversable transformation. Transforms buffer in-place; may add
 342    data to start or end. Maximum amount of data to be added specified
 343    in max_start_pad and max_end_pad. (Reverse transformations decrease
 344    length, of course.)  Transformations may be key-dependent, in which
 345    case key material is passed in at initialisation time. They may
 346    also depend on internal factors (eg. time) and keep internal
 347    state. A struct transform_if only represents a particular type of
 348    transformation; instances of the transformation (eg. with
 349    particular key material) have a different C type. */
 350
 351 typedef struct transform_inst_if *transform_createinstance_fn(void *st);
 352 typedef bool_t transform_setkey_fn(void *st, uint8_t *key, uint32_t keylen);
 353 typedef void transform_delkey_fn(void *st);
 354 typedef void transform_destroyinstance_fn(void *st);
 355 /* Returns 0 for 'all is well', any other value for a problem */
 356 typedef uint32_t transform_apply_fn(void *st, struct buffer_if *buf,
 357                                     char **errmsg);
 358
 359 struct transform_inst_if {
 360     void *st;
 361     transform_setkey_fn *setkey;
 362     transform_delkey_fn *delkey;
 363     transform_apply_fn *forwards;
 364     transform_apply_fn *reverse;
 365     transform_destroyinstance_fn *destroy;
 366 };
 367
 368 struct transform_if {
 369     void *st;
 370     uint32_t max_start_pad;
 371     uint32_t max_end_pad;
 372     uint32_t keylen;
 373     transform_createinstance_fn *create;
 374 };
 375
 376 /* NETLINK interface */
 377
 378 /* Used by netlink to deliver to site, and by site to deliver to
 379    netlink.  cid is the client identifier returned by
 380    netlink_regnets_fn.  If buf has size 0 then the function is just
 381    being called for its site-effects (eg. making the site code attempt
 382    to bring up a network link) */
 383 typedef void netlink_deliver_fn(void *st, void *cid, struct buffer_if *buf);
 384 /* site code can tell netlink when outgoing packets will be dropped,
 385    so netlink can generate appropriate ICMP and make routing decisions */
 386 #define LINK_QUALITY_DOWN 0   /* No chance of a packet being delivered */
 387 #define LINK_QUALITY_DOWN_STALE_ADDRESS 1 /* Link down, old address information */
 388 #define LINK_QUALITY_DOWN_CURRENT_ADDRESS 2 /* Link down, current address information */
 389 #define LINK_QUALITY_UP 3     /* Link active */
 390 #define MAXIMUM_LINK_QUALITY 3
 391 typedef void netlink_link_quality_fn(void *st, void *cid, uint32_t quality);
 392 /* Register for packets from specified networks. Return value is
 393    client identifier.  'hard_route' indicates whether the routes being
 394    registered are permanent (hard) or temporary (soft); some types of
 395    netlink device can only cope with hard routes. */
 396 #define NETLINK_OPTION_SOFTROUTE    1
 397 #define NETLINK_OPTION_ALLOW_ROUTE  2
 398 typedef void *netlink_regnets_fn(void *st, struct subnet_list *networks,
 399                                  netlink_deliver_fn *deliver, void *dst,
 400                                  uint32_t max_start_pad, uint32_t max_end_pad,
 401                                  uint32_t options, string_t client_name);
 402
 403 struct netlink_if {
 404     void *st;
 405     netlink_regnets_fn *regnets;
 406     netlink_deliver_fn *deliver;
 407     netlink_link_quality_fn *set_quality;
 408 };
 409
 410 /* DH interface */
 411
 412 /* Returns public key as a malloced hex string */
 413 typedef string_t dh_makepublic_fn(void *st, uint8_t *secret,
 414                                   uint32_t secretlen);
 415 /* Fills buffer (up to buflen) with shared secret */
 416 typedef void dh_makeshared_fn(void *st, uint8_t *secret,
 417                               uint32_t secretlen, string_t rempublic,
 418                               uint8_t *sharedsecret, uint32_t buflen);
 419 struct dh_if {
 420     void *st;
 421     uint32_t len; /* Approximate size of modulus in bytes */
 422     dh_makepublic_fn *makepublic;
 423     dh_makeshared_fn *makeshared;
 424 };
 425
 426 /* HASH interface */
 427
 428 typedef void *hash_init_fn(void);
 429 typedef void hash_update_fn(void *st, uint8_t const *buf, uint32_t len);
 430 typedef void hash_final_fn(void *st, uint8_t *digest);
 431 struct hash_if {
 432     uint32_t len; /* Hash output length in bytes */
 433     hash_init_fn *init;
 434     hash_update_fn *update;
 435     hash_final_fn *final;
 436 };
 437
 438 /* BUFFER interface */
 439
 440 struct buffer_if {
 441     bool_t free;
 442     string_t owner; /* Set to constant string */
 443     uint32_t flags; /* How paranoid should we be? */
 444     struct cloc loc; /* Where we were defined */
 445     uint8_t *base;
 446     uint8_t *start;
 447     uint32_t size; /* Size of buffer contents */
 448     uint32_t len; /* Total length allocated at base */
 449 };
 450
 451 #endif /* secnet_h */