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