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 /***** END of shared types *****/
  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     string_t file;
  50     uint32_t 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     string_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 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, string_t key);
  86 /* Lookup a value in just the specified dictionary */
  87 extern list_t *dict_lookup_primitive(dict_t *dict, string_t key);
  88 /* Add a value to the specified dictionary */
  89 extern void dict_add(dict_t *dict, string_t key, list_t *val);
  90 /* Obtain an array of keys in the dictionary. malloced; caller frees */
  91 extern string_t *dict_keys(dict_t *dict);
  92
  93 /* List-manipulation functions */
  94 extern list_t *list_new(void);
  95 extern uint32_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, uint32_t index);
 100
 101 /* Convenience functions */
 102 extern list_t *new_closure(closure_t *cl);
 103 extern void add_closure(dict_t *dict, string_t name, apply_fn apply);
 104 extern void *find_cl_if(dict_t *dict, string_t name, uint32_t type,
 105                         bool_t fail_if_invalid, string_t desc,
 106                         struct cloc loc);
 107 extern item_t *dict_find_item(dict_t *dict, string_t key, bool_t required,
 108                               string_t desc, struct cloc loc);
 109 extern string_t dict_read_string(dict_t *dict, string_t key, bool_t required,
 110                                  string_t desc, struct cloc loc);
 111 extern uint32_t dict_read_number(dict_t *dict, string_t key, bool_t required,
 112                                  string_t desc, struct cloc loc, uint32_t def);
 113 extern bool_t dict_read_bool(dict_t *dict, string_t key, bool_t required,
 114                              string_t desc, struct cloc loc, bool_t def);
 115 extern void dict_read_subnet_list(dict_t *dict, string_t key, bool_t required,
 116                                   string_t desc, struct cloc loc,
 117                                   struct subnet_list *sl);
 118 extern uint32_t string_to_ipaddr(item_t *i, string_t desc);
 119 struct flagstr {
 120     string_t name;
 121     uint32_t value;
 122 };
 123 extern uint32_t string_to_word(string_t s, struct cloc loc,
 124                                struct flagstr *f, string_t desc);
 125 extern uint32_t string_list_to_word(list_t *l, struct flagstr *f,
 126                                     string_t desc);
 127
 128 /***** END of configuration support *****/
 129
 130 /***** LOG functions *****/
 131
 132 #define M_DEBUG_CONFIG 0x001
 133 #define M_DEBUG_PHASE  0x002
 134 #define M_DEBUG        0x004
 135 #define M_INFO         0x008
 136 #define M_NOTICE       0x010
 137 #define M_WARNING      0x020
 138 #define M_ERROR        0x040
 139 #define M_SECURITY     0x080
 140 #define M_FATAL        0x100
 141
 142 extern void fatal(char *message, ...);
 143 extern void fatal_perror(char *message, ...);
 144 extern void fatal_status(int status, char *message, ...);
 145 extern void fatal_perror_status(int status, char *message, ...);
 146 extern void cfgfatal(struct cloc loc, string_t facility, char *message, ...);
 147
 148 extern void Message(uint32_t class, char *message, ...);
 149
 150 /***** END of log functions *****/
 151
 152 /***** UTILITY functions *****/
 153
 154 extern char *safe_strdup(char *string, char *message);
 155 extern void *safe_malloc(size_t size, char *message);
 156
 157 extern int sys_cmd(const char *file, char *argc, ...);
 158
 159 /***** END of utility functions *****/
 160
 161 /***** SCHEDULING support */
 162
 163 /* "now" is current program time, in milliseconds. It is derived
 164    (once) from tv_now. If nfds_io is insufficient for your needs, set
 165    it to the required number and return ERANGE. timeout is in milliseconds;
 166    if it is too high then lower it. It starts at -1 (==infinite) */
 167 typedef int beforepoll_fn(void *st, struct pollfd *fds, int *nfds_io,
 168                           int *timeout_io, const struct timeval *tv_now,
 169                           uint64_t *now);
 170 typedef void afterpoll_fn(void *st, struct pollfd *fds, int nfds,
 171                           const struct timeval *tv_now, uint64_t *now);
 172
 173 /* Register interest in the main loop of the program. Before a call
 174    to poll() your supplied beforepoll function will be called. After
 175    the call to poll() the supplied afterpoll function will be called.
 176    max_nfds is a _hint_ about the maximum number of struct pollfd
 177    structures you may require - you can always ask for more in
 178    *nfds_io. */
 179 extern void register_for_poll(void *st, beforepoll_fn *before,
 180                               afterpoll_fn *after, uint32_t max_nfds,
 181                               string_t desc);
 182
 183 /***** END of scheduling support */
 184
 185 /***** PROGRAM LIFETIME support */
 186
 187 /* The secnet program goes through a number of phases in its lifetime.
 188    Module code may arrange to be called just as various phases are
 189    entered. */
 190
 191 #define PHASE_INIT          0
 192 #define PHASE_GETOPTS       1  /* Process command-line arguments */
 193 #define PHASE_READCONFIG    2  /* Parse and process configuration file */
 194 #define PHASE_SETUP         3  /* Process information in configuration */
 195 #define PHASE_GETRESOURCES  4  /* Obtain all external resources */
 196 #define PHASE_DROPPRIV      5  /* Last chance for privileged operations */
 197 #define PHASE_RUN           6
 198 #define PHASE_SHUTDOWN      7  /* About to die; delete key material, etc. */
 199 #define NR_PHASES           8
 200
 201 typedef void hook_fn(void *self, uint32_t newphase);
 202 bool_t add_hook(uint32_t phase, hook_fn *f, void *state);
 203 bool_t remove_hook(uint32_t phase, hook_fn *f, void *state);
 204
 205 extern uint32_t current_phase;
 206 extern void enter_phase(uint32_t new_phase);
 207
 208 extern bool_t require_root_privileges; /* Some features (like netlink
 209                                           'soft' routes) require that
 210                                           secnet retain root
 211                                           privileges.  They should
 212                                           indicate that here when
 213                                           appropriate. */
 214 extern string_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 /***** END of module support *****/
 226
 227 /***** CLOSURE TYPES and interface definitions *****/
 228
 229 #define CL_PURE        0
 230 #define CL_RESOLVER    1
 231 #define CL_RANDOMSRC   2
 232 #define CL_RSAPUBKEY   3
 233 #define CL_RSAPRIVKEY  4
 234 #define CL_COMM        5
 235 #define CL_IPIF        6
 236 #define CL_LOG         7
 237 #define CL_SITE        8
 238 #define CL_TRANSFORM   9
 239 #define CL_NETLINK    10
 240 #define CL_DH         11
 241 #define CL_HASH       12
 242 #define CL_BUFFER     13
 243
 244 struct buffer_if;
 245
 246 /* PURE closure requires no interface */
 247
 248 /* RESOLVER interface */
 249
 250 /* Answers to queries are delivered to a function of this
 251    type. 'address' will be NULL if there was a problem with the query. It
 252    will be freed once resolve_answer_fn returns. It is in network byte
 253    order. */
 254 typedef void resolve_answer_fn(void *st, struct in_addr *addr);
 255 typedef bool_t resolve_request_fn(void *st, string_t name,
 256                                   resolve_answer_fn *cb, void *cst);
 257 struct resolver_if {
 258     void *st;
 259     resolve_request_fn *request;
 260 };
 261
 262 /* RANDOMSRC interface */
 263
 264 /* Return some random data. Returns TRUE for success. */
 265 typedef bool_t random_fn(void *st, uint32_t bytes, uint8_t *buff);
 266
 267 struct random_if {
 268     void *st;
 269     bool_t blocking;
 270     random_fn *generate;
 271 };
 272
 273 /* RSAPUBKEY interface */
 274
 275 typedef bool_t rsa_checksig_fn(void *st, uint8_t *data, uint32_t datalen,
 276                                string_t signature);
 277 struct rsapubkey_if {
 278     void *st;
 279     rsa_checksig_fn *check;
 280 };
 281
 282 /* RSAPRIVKEY interface */
 283
 284 typedef string_t rsa_makesig_fn(void *st, uint8_t *data, uint32_t datalen);
 285 struct rsaprivkey_if {
 286     void *st;
 287     rsa_makesig_fn *sign;
 288 };
 289
 290 /* COMM interface */
 291
 292 /* Return True if the packet was processed, and shouldn't be passed to
 293    any other potential receivers. */
 294 typedef bool_t comm_notify_fn(void *state, struct buffer_if *buf,
 295                             struct sockaddr_in *source);
 296 typedef void comm_request_notify_fn(void *commst, void *nst,
 297                                     comm_notify_fn *fn);
 298 typedef void comm_release_notify_fn(void *commst, void *nst,
 299                                     comm_notify_fn *fn);
 300 typedef bool_t comm_sendmsg_fn(void *commst, struct buffer_if *buf,
 301                                struct sockaddr_in *dest);
 302 struct comm_if {
 303     void *st;
 304     comm_request_notify_fn *request_notify;
 305     comm_release_notify_fn *release_notify;
 306     comm_sendmsg_fn *sendmsg;
 307 };
 308
 309 /* LOG interface */
 310
 311 typedef void log_msg_fn(void *st, int class, char *message, ...);
 312 typedef void log_vmsg_fn(void *st, int class, char *message, va_list args);
 313 struct log_if {
 314     void *st;
 315     log_msg_fn *log;
 316     log_vmsg_fn *vlog;
 317 };
 318 /* (convenience function, defined in util.c) */
 319 extern void log(struct log_if *lf, int class, char *message, ...);
 320
 321 /* SITE interface */
 322
 323 /* Pretty much a placeholder; allows starting and stopping of processing,
 324    key expiry, etc. */
 325 typedef void site_control_fn(void *st, bool_t run);
 326 typedef uint32_t site_status_fn(void *st);
 327 struct site_if {
 328     void *st;
 329     site_control_fn *control;
 330     site_status_fn *status;
 331 };
 332
 333 /* TRANSFORM interface */
 334
 335 /* A reversable transformation. Transforms buffer in-place; may add
 336    data to start or end. Maximum amount of data to be added specified
 337    in max_start_pad and max_end_pad. (Reverse transformations decrease
 338    length, of course.)  Transformations may be key-dependent, in which
 339    case key material is passed in at initialisation time. They may
 340    also depend on internal factors (eg. time) and keep internal
 341    state. A struct transform_if only represents a particular type of
 342    transformation; instances of the transformation (eg. with
 343    particular key material) have a different C type. */
 344
 345 typedef struct transform_inst_if *transform_createinstance_fn(void *st);
 346 typedef bool_t transform_setkey_fn(void *st, uint8_t *key, uint32_t keylen);
 347 typedef void transform_delkey_fn(void *st);
 348 typedef void transform_destroyinstance_fn(void *st);
 349 /* Returns 0 for 'all is well', any other value for a problem */
 350 typedef uint32_t transform_apply_fn(void *st, struct buffer_if *buf,
 351                                     char **errmsg);
 352
 353 struct transform_inst_if {
 354     void *st;
 355     transform_setkey_fn *setkey;
 356     transform_delkey_fn *delkey;
 357     transform_apply_fn *forwards;
 358     transform_apply_fn *reverse;
 359     transform_destroyinstance_fn *destroy;
 360 };
 361
 362 struct transform_if {
 363     void *st;
 364     uint32_t max_start_pad;
 365     uint32_t max_end_pad;
 366     uint32_t keylen;
 367     transform_createinstance_fn *create;
 368 };
 369
 370 /* NETLINK interface */
 371
 372 /* Used by netlink to deliver to site, and by site to deliver to
 373    netlink.  cid is the client identifier returned by
 374    netlink_regnets_fn.  If buf has size 0 then the function is just
 375    being called for its site-effects (eg. making the site code attempt
 376    to bring up a network link) */
 377 typedef void netlink_deliver_fn(void *st, void *cid, struct buffer_if *buf);
 378 /* site code can tell netlink when outgoing packets will be dropped,
 379    so netlink can generate appropriate ICMP and make routing decisions */
 380 #define LINK_QUALITY_DOWN 0   /* No chance of a packet being delivered */
 381 #define LINK_QUALITY_DOWN_STALE_ADDRESS 1 /* Link down, old address information */
 382 #define LINK_QUALITY_DOWN_CURRENT_ADDRESS 2 /* Link down, current address information */
 383 #define LINK_QUALITY_UP 3     /* Link active */
 384 #define MAXIMUM_LINK_QUALITY 3
 385 typedef void netlink_link_quality_fn(void *st, void *cid, uint32_t quality);
 386 /* Register for packets from specified networks. Return value is
 387    client identifier.  'hard_route' indicates whether the routes being
 388    registered are permanent (hard) or temporary (soft); some types of
 389    netlink device can only cope with hard routes. */
 390 #define NETLINK_OPTION_SOFTROUTE    1
 391 #define NETLINK_OPTION_ALLOW_ROUTE  2
 392 typedef void *netlink_regnets_fn(void *st, struct subnet_list *networks,
 393                                  netlink_deliver_fn *deliver, void *dst,
 394                                  uint32_t max_start_pad, uint32_t max_end_pad,
 395                                  uint32_t options, string_t client_name);
 396
 397 struct netlink_if {
 398     void *st;
 399     netlink_regnets_fn *regnets;
 400     netlink_deliver_fn *deliver;
 401     netlink_link_quality_fn *set_quality;
 402 };
 403
 404 /* DH interface */
 405
 406 /* Returns public key as a malloced hex string */
 407 typedef string_t dh_makepublic_fn(void *st, uint8_t *secret,
 408                                   uint32_t secretlen);
 409 /* Fills buffer (up to buflen) with shared secret */
 410 typedef void dh_makeshared_fn(void *st, uint8_t *secret,
 411                               uint32_t secretlen, string_t rempublic,
 412                               uint8_t *sharedsecret, uint32_t buflen);
 413 struct dh_if {
 414     void *st;
 415     uint32_t len; /* Approximate size of modulus in bytes */
 416     dh_makepublic_fn *makepublic;
 417     dh_makeshared_fn *makeshared;
 418 };
 419
 420 /* HASH interface */
 421
 422 typedef void *hash_init_fn(void);
 423 typedef void hash_update_fn(void *st, uint8_t const *buf, uint32_t len);
 424 typedef void hash_final_fn(void *st, uint8_t *digest);
 425 struct hash_if {
 426     uint32_t len; /* Hash output length in bytes */
 427     hash_init_fn *init;
 428     hash_update_fn *update;
 429     hash_final_fn *final;
 430 };
 431
 432 /* BUFFER interface */
 433
 434 struct buffer_if {
 435     bool_t free;
 436     string_t owner; /* Set to constant string */
 437     uint32_t flags; /* How paranoid should we be? */
 438     struct cloc loc; /* Where we were defined */
 439     uint8_t *base;
 440     uint8_t *start;
 441     uint32_t size; /* Size of buffer contents */
 442     uint32_t len; /* Total length allocated at base */
 443 };
 444
 445 #endif /* secnet_h */