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