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