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 <stdlib.h>
   7 #include <stdint.h>
   8 #include <stdarg.h>
   9 #include <syslog.h>
  10 #include <sys/poll.h>
  11 #include <netinet/in.h>
  12 #include "config.h"
  13
  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 " __LINE__ \
  19                                          " file " __FILE__ "\n"); } while(0)
  20
  21 /***** SHARED types *****/
  22
  23 /* These are stored in HOST byte order */
  24 struct subnet {
  25     uint32_t prefix;
  26     uint32_t mask;
  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_list *list, uint32_t address);
  37
  38 /***** END of shared types *****/
  39
  40 /***** CONFIGURATION support *****/
  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 list_t *list_append(list_t *a, item_t *i);
  96 extern list_t *list_append_list(list_t *a, list_t *b);
  97 /* Returns an item from the list (index starts at 0), or NULL */
  98 extern item_t *list_elem(list_t *l, uint32_t index);
  99
 100 /* Convenience functions */
 101 extern list_t *new_closure(closure_t *cl);
 102 extern void add_closure(dict_t *dict, string_t name, apply_fn apply);
 103 extern void *find_cl_if(dict_t *dict, string_t name, uint32_t type,
 104                         bool_t fail_if_invalid, string_t desc,
 105                         struct cloc loc);
 106 extern item_t *dict_find_item(dict_t *dict, string_t key, bool_t required,
 107                               string_t desc, struct cloc loc);
 108 extern string_t dict_read_string(dict_t *dict, string_t key, bool_t required,
 109                                  string_t desc, struct cloc loc);
 110 extern uint32_t dict_read_number(dict_t *dict, string_t key, bool_t required,
 111                                  string_t desc, struct cloc loc, uint32_t def);
 112 extern bool_t dict_read_bool(dict_t *dict, string_t key, bool_t required,
 113                              string_t desc, struct cloc loc, bool_t def);
 114 extern void dict_read_subnet_list(dict_t *dict, string_t key, bool_t required,
 115                                   string_t desc, struct cloc loc,
 116                                   struct subnet_list *sl);
 117 extern uint32_t string_to_ipaddr(item_t *i, string_t desc);
 118
 119 /***** END of configuration support *****/
 120
 121 /***** UTILITY functions *****/
 122
 123 #define M_WARNING       1
 124 #define M_ERROR         2
 125 #define M_FATAL         4
 126 #define M_INFO          8
 127 #define M_DEBUG_CONFIG 16
 128 #define M_DEBUG_PHASE  32
 129
 130 extern void fatal(char *message, ...);
 131 extern void fatal_perror(char *message, ...);
 132 extern void fatal_status(int status, char *message, ...);
 133 extern void fatal_perror_status(int status, char *message, ...);
 134 extern void cfgfatal(struct cloc loc, string_t facility, char *message, ...);
 135
 136 extern char *safe_strdup(char *string, char *message);
 137 extern void *safe_malloc(size_t size, char *message);
 138
 139 extern void Message(uint32_t class, char *message, ...);
 140
 141 extern string_t ipaddr_to_string(uint32_t addr);
 142 extern string_t subnet_to_string(struct subnet *sn);
 143
 144 /***** END of utility functions *****/
 145
 146 /***** SCHEDULING support */
 147
 148 /* "now" is current program time, in milliseconds. It is derived
 149    (once) from tv_now. If nfds_io is insufficient for your needs, set
 150    it to the required number and return ERANGE. timeout is in milliseconds;
 151    if it is too high then lower it. It starts at -1 (==infinite) */
 152 typedef int beforepoll_fn(void *st, struct pollfd *fds, int *nfds_io,
 153                           int *timeout_io, const struct timeval *tv_now,
 154                           uint64_t *now);
 155 typedef void afterpoll_fn(void *st, struct pollfd *fds, int nfds,
 156                           const struct timeval *tv_now, uint64_t *now);
 157
 158 /* Register interest in the main loop of the program. Before a call
 159    to poll() your supplied beforepoll function will be called. After
 160    the call to poll() the supplied afterpoll function will be called.
 161    max_nfds is a _hint_ about the maximum number of struct pollfd
 162    structures you may require - you can always ask for more in
 163    *nfds_io. */
 164 extern void register_for_poll(void *st, beforepoll_fn *before,
 165                               afterpoll_fn *after, uint32_t max_nfds,
 166                               string_t desc);
 167
 168 /***** END of scheduling support */
 169
 170 /***** PROGRAM LIFETIME support */
 171
 172 /* The secnet program goes through a number of phases in its lifetime.
 173    Module code may arrange to be called just as various phases are
 174    entered. */
 175
 176 #define PHASE_INIT          0
 177 #define PHASE_GETOPTS       1  /* Process command-line arguments */
 178 #define PHASE_READCONFIG    2  /* Parse and process configuration file */
 179 #define PHASE_SETUP         3  /* Process information in configuration */
 180 #define PHASE_DROPPRIV      4  /* Last chance for privileged operations */
 181 #define PHASE_RUN           5
 182 #define PHASE_SHUTDOWN      6  /* About to die; delete key material, etc. */
 183 #define NR_PHASES           7
 184
 185 typedef void hook_fn(void *self, uint32_t newphase);
 186 bool_t add_hook(uint32_t phase, hook_fn *f, void *state);
 187 bool_t remove_hook(uint32_t phase, hook_fn *f, void *state);
 188
 189 /***** END of program lifetime support *****/
 190
 191 /***** MODULE support *****/
 192
 193 /* Module initialisation function type - modules export one function of
 194    this type which is called to initialise them. For dynamically loaded
 195    modules it's called "secnet_module". */
 196 typedef void (init_module)(dict_t *dict);
 197
 198 /***** END of module support *****/
 199
 200 /***** CLOSURE TYPES and interface definitions *****/
 201
 202 #define CL_PURE        0
 203 #define CL_RESOLVER    1
 204 #define CL_RANDOMSRC   2
 205 #define CL_RSAPUBKEY   3
 206 #define CL_RSAPRIVKEY  4
 207 #define CL_COMM        5
 208 #define CL_IPIF        6
 209 #define CL_LOG         7
 210 #define CL_SITE        8
 211 #define CL_TRANSFORM   9
 212 #define CL_NETLINK    10
 213 #define CL_DH         11
 214 #define CL_HASH       12
 215 #define CL_BUFFER     13
 216
 217 struct buffer_if;
 218
 219 /* PURE closure requires no interface */
 220
 221 /* RESOLVER interface */
 222
 223 /* Answers to queries are delivered to a function of this
 224    type. 'address' will be NULL if there was a problem with the query. It
 225    will be freed once resolve_answer_fn returns. It is in network byte
 226    order. */
 227 typedef void resolve_answer_fn(void *st, struct in_addr *addr);
 228 typedef bool_t resolve_request_fn(void *st, string_t name,
 229                                   resolve_answer_fn *cb, void *cst);
 230 struct resolver_if {
 231     void *st;
 232     resolve_request_fn *request;
 233 };
 234
 235 /* RANDOMSRC interface */
 236
 237 /* Return some random data. Returns TRUE for success. */
 238 typedef bool_t random_fn(void *st, uint32_t bytes, uint8_t *buff);
 239
 240 struct random_if {
 241     void *st;
 242     bool_t blocking;
 243     random_fn *generate;
 244 };
 245
 246 /* RSAPUBKEY interface */
 247
 248 typedef bool_t rsa_checksig_fn(void *st, uint8_t *data, uint32_t datalen,
 249                                string_t signature);
 250 struct rsapubkey_if {
 251     void *st;
 252     rsa_checksig_fn *check;
 253 };
 254
 255 /* RSAPRIVKEY interface */
 256
 257 typedef string_t rsa_makesig_fn(void *st, uint8_t *data, uint32_t datalen);
 258 struct rsaprivkey_if {
 259     void *st;
 260     rsa_makesig_fn *sign;
 261 };
 262
 263 /* COMM interface */
 264
 265 /* Return True if the packet was processed, and shouldn't be passed to
 266    any other potential receivers. */
 267 typedef bool_t comm_notify_fn(void *state, struct buffer_if *buf,
 268                             struct sockaddr_in *source);
 269 typedef void comm_request_notify_fn(void *commst, void *nst,
 270                                     comm_notify_fn *fn);
 271 typedef void comm_release_notify_fn(void *commst, void *nst,
 272                                     comm_notify_fn *fn);
 273 typedef bool_t comm_sendmsg_fn(void *commst, struct buffer_if *buf,
 274                                struct sockaddr_in *dest);
 275 struct comm_if {
 276     void *st;
 277     comm_request_notify_fn *request_notify;
 278     comm_release_notify_fn *release_notify;
 279     comm_sendmsg_fn *sendmsg;
 280 };
 281
 282 /* LOG interface */
 283
 284 typedef void log_msg_fn(void *st, int priority, char *message, ...);
 285 typedef void log_vmsg_fn(void *st, int priority, char *message, va_list args);
 286 struct log_if {
 287     void *st;
 288     log_msg_fn *log;
 289     log_vmsg_fn *vlog;
 290 };
 291 /* (convenience function, defined in util.c) */
 292 extern void log(struct log_if *lf, int priority, char *message, ...);
 293
 294 /* SITE interface */
 295
 296 /* Pretty much a placeholder; allows starting and stopping of processing,
 297    key expiry, etc. */
 298 typedef void site_control_fn(void *st, bool_t run);
 299 typedef uint32_t site_status_fn(void *st);
 300 struct site_if {
 301     void *st;
 302     site_control_fn *control;
 303     site_status_fn *status;
 304 };
 305
 306 /* TRANSFORM interface */
 307
 308 /* A reversable transformation. Transforms buffer in-place; may add
 309    data to start or end. Maximum amount of data to be added specified
 310    in max_start_pad and max_end_pad. (Reverse transformations decrease
 311    length, of course.)  Transformations may be key-dependent, in which
 312    case key material is passed in at initialisation time. They may
 313    also depend on internal factors (eg. time) and keep internal
 314    state. A struct transform_if only represents a particular type of
 315    transformation; instances of the transformation (eg. with
 316    particular key material) have a different C type. */
 317
 318 typedef struct transform_inst_if *transform_createinstance_fn(void *st);
 319 typedef bool_t transform_setkey_fn(void *st, uint8_t *key, uint32_t keylen);
 320 typedef void transform_delkey_fn(void *st);
 321 typedef void transform_destroyinstance_fn(void *st);
 322 /* Returns 0 for 'all is well', any other value for a problem */
 323 typedef uint32_t transform_apply_fn(void *st, struct buffer_if *buf,
 324                                     char **errmsg);
 325
 326 struct transform_inst_if {
 327     void *st;
 328     transform_setkey_fn *setkey;
 329     transform_delkey_fn *delkey;
 330     transform_apply_fn *forwards;
 331     transform_apply_fn *reverse;
 332     transform_destroyinstance_fn *destroy;
 333 };
 334
 335 struct transform_if {
 336     void *st;
 337     uint32_t max_start_pad;
 338     uint32_t max_end_pad;
 339     uint32_t keylen;
 340     transform_createinstance_fn *create;
 341 };
 342
 343 /* NETLINK interface */
 344
 345 /* Used by netlink to deliver to site, and by site to deliver to netlink.
 346    cid is the client identifier returned by netlink_regnets_fn */
 347 typedef void netlink_deliver_fn(void *st, void *cid, struct buffer_if *buf);
 348 /* Register for packets from specified networks. Return value is client
 349    identifier. */
 350 typedef void *netlink_regnets_fn(void *st, struct subnet_list *networks,
 351                                  netlink_deliver_fn *deliver, void *dst,
 352                                  uint32_t max_start_pad, uint32_t max_end_pad);
 353
 354 struct netlink_if {
 355     void *st;
 356     netlink_regnets_fn *regnets;
 357     netlink_deliver_fn *deliver;
 358 };
 359
 360 /* DH interface */
 361
 362 /* Returns public key as a malloced hex string */
 363 typedef string_t dh_makepublic_fn(void *st, uint8_t *secret,
 364                                   uint32_t secretlen);
 365 /* Fills buffer (up to buflen) with shared secret */
 366 typedef void dh_makeshared_fn(void *st, uint8_t *secret,
 367                               uint32_t secretlen, string_t rempublic,
 368                               uint8_t *sharedsecret, uint32_t buflen);
 369 struct dh_if {
 370     void *st;
 371     uint32_t len; /* Approximate size of modulus in bytes */
 372     dh_makepublic_fn *makepublic;
 373     dh_makeshared_fn *makeshared;
 374 };
 375
 376 /* HASH interface */
 377
 378 typedef void *hash_init_fn(void);
 379 typedef void hash_update_fn(void *st, uint8_t const *buf, uint32_t len);
 380 typedef void hash_final_fn(void *st, uint8_t *digest);
 381 struct hash_if {
 382     uint32_t len; /* Hash output length in bytes */
 383     hash_init_fn *init;
 384     hash_update_fn *update;
 385     hash_final_fn *final;
 386 };
 387
 388 /* BUFFER interface */
 389
 390 struct buffer_if {
 391     bool_t free;
 392     string_t owner; /* Set to constant string */
 393     uint32_t flags; /* How paranoid should we be? */
 394     struct cloc loc; /* Where we were defined */
 395     uint8_t *base;
 396     uint8_t *start;
 397     uint32_t size; /* Size of buffer contents */
 398     uint32_t len; /* Total length allocated at base */
 399 };
 400
 401 #endif /* secnet_h */