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 <syslog.h>
  10 #include <sys/poll.h>
  11 #include <netinet/in.h>
  12
  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 };
  27
  28 struct subnet_list {
  29     uint32_t entries;
  30     struct subnet *list;
  31 };
  32
  33 /* Match an address (in HOST byte order) with a subnet list.
  34    Returns True if matched. */
  35 extern bool_t subnet_match(struct subnet_list *list, uint32_t address);
  36
  37 /***** END of shared types *****/
  38
  39 /***** CONFIGURATION support *****/
  40
  41 typedef struct dict dict_t;        /* Configuration dictionary */
  42 typedef struct closure closure_t;
  43 typedef struct item item_t;
  44 typedef struct list list_t;        /* A list of items */
  45
  46 /* Configuration file location, for error-reporting */
  47 struct cloc {
  48     string_t file;
  49     uint32_t line;
  50 };
  51
  52 /* Modules export closures, which can be invoked from the configuration file.
  53    "Invoking" a closure usually returns another closure (of a different
  54    type), but can actually return any configuration object. */
  55 typedef list_t *(apply_fn)(closure_t *self, struct cloc loc,
  56                            dict_t *context, list_t *data);
  57 struct closure {
  58     string_t description; /* For debugging */
  59     uint32_t type; /* Central registry... */
  60     apply_fn *apply;
  61     void *interface; /* Interface for use inside secnet; depends on type */
  62 };
  63
  64 enum types { t_null, t_bool, t_string, t_number, t_dict, t_closure };
  65 struct item {
  66     enum types type;
  67     union {
  68         bool_t bool;
  69         string_t string;
  70         uint32_t number;
  71         dict_t *dict;
  72         closure_t *closure;
  73     } data;
  74     struct cloc loc;
  75 };
  76
  77 struct list {
  78     item_t *item;
  79     struct list *next;
  80 };
  81
  82 /* In the following two lookup functions, NULL means 'not found' */
  83 /* Lookup a value in the specified dictionary, or its parents */
  84 extern list_t *dict_lookup(dict_t *dict, string_t key);
  85 /* Lookup a value in just the specified dictionary */
  86 extern list_t *dict_lookup_primitive(dict_t *dict, string_t key);
  87 /* Add a value to the specified dictionary */
  88 extern void dict_add(dict_t *dict, string_t key, list_t *val);
  89 /* Obtain an array of keys in the dictionary. malloced; caller frees */
  90 extern string_t *dict_keys(dict_t *dict);
  91
  92 /* List-manipulation functions */
  93 extern list_t *list_new(void);
  94 extern list_t *list_append(list_t *a, item_t *i);
  95 extern list_t *list_append_list(list_t *a, list_t *b);
  96 /* Returns an item from the list (index starts at 0), or NULL */
  97 extern item_t *list_elem(list_t *l, uint32_t index);
  98
  99 /* Convenience functions */
 100 extern list_t *new_closure(closure_t *cl);
 101 extern void add_closure(dict_t *dict, string_t name, apply_fn apply);
 102 extern void *find_cl_if(dict_t *dict, string_t name, uint32_t type,
 103                         bool_t fail_if_invalid, string_t desc,
 104                         struct cloc loc);
 105 extern item_t *dict_find_item(dict_t *dict, string_t key, bool_t required,
 106                               string_t desc, struct cloc loc);
 107 extern string_t dict_read_string(dict_t *dict, string_t key, bool_t required,
 108                                  string_t desc, struct cloc loc);
 109 extern uint32_t dict_read_number(dict_t *dict, string_t key, bool_t required,
 110                                  string_t desc, struct cloc loc, uint32_t def);
 111 extern bool_t dict_read_bool(dict_t *dict, string_t key, bool_t required,
 112                              string_t desc, struct cloc loc, bool_t def);
 113 extern void dict_read_subnet_list(dict_t *dict, string_t key, bool_t required,
 114                                   string_t desc, struct cloc loc,
 115                                   struct subnet_list *sl);
 116 extern uint32_t string_to_ipaddr(item_t *i, string_t desc);
 117
 118 /***** END of configuration support *****/
 119
 120 /***** UTILITY functions *****/
 121
 122 #define M_WARNING       1
 123 #define M_ERROR         2
 124 #define M_FATAL         4
 125 #define M_INFO          8
 126 #define M_DEBUG_CONFIG 16
 127 #define M_DEBUG_PHASE  32
 128
 129 extern void fatal(char *message, ...);
 130 extern void fatal_perror(char *message, ...);
 131 extern void fatal_status(int status, char *message, ...);
 132 extern void fatal_perror_status(int status, char *message, ...);
 133 extern void cfgfatal(struct cloc loc, string_t facility, char *message, ...);
 134
 135 extern char *safe_strdup(char *string, char *message);
 136 extern void *safe_malloc(size_t size, char *message);
 137
 138 extern void Message(uint32_t class, char *message, ...);
 139
 140 extern string_t ipaddr_to_string(uint32_t addr);
 141 extern string_t subnet_to_string(struct subnet *sn);
 142
 143 extern int sys_cmd(const char *file, char *argc, ...);
 144
 145 /***** END of utility functions *****/
 146
 147 /***** SCHEDULING support */
 148
 149 /* "now" is current program time, in milliseconds. It is derived
 150    (once) from tv_now. If nfds_io is insufficient for your needs, set
 151    it to the required number and return ERANGE. timeout is in milliseconds;
 152    if it is too high then lower it. It starts at -1 (==infinite) */
 153 typedef int beforepoll_fn(void *st, struct pollfd *fds, int *nfds_io,
 154                           int *timeout_io, const struct timeval *tv_now,
 155                           uint64_t *now);
 156 typedef void afterpoll_fn(void *st, struct pollfd *fds, int nfds,
 157                           const struct timeval *tv_now, uint64_t *now);
 158
 159 /* Register interest in the main loop of the program. Before a call
 160    to poll() your supplied beforepoll function will be called. After
 161    the call to poll() the supplied afterpoll function will be called.
 162    max_nfds is a _hint_ about the maximum number of struct pollfd
 163    structures you may require - you can always ask for more in
 164    *nfds_io. */
 165 extern void register_for_poll(void *st, beforepoll_fn *before,
 166                               afterpoll_fn *after, uint32_t max_nfds,
 167                               string_t desc);
 168
 169 /***** END of scheduling support */
 170
 171 /***** PROGRAM LIFETIME support */
 172
 173 /* The secnet program goes through a number of phases in its lifetime.
 174    Module code may arrange to be called just as various phases are
 175    entered. */
 176
 177 #define PHASE_INIT          0
 178 #define PHASE_GETOPTS       1  /* Process command-line arguments */
 179 #define PHASE_READCONFIG    2  /* Parse and process configuration file */
 180 #define PHASE_SETUP         3  /* Process information in configuration */
 181 #define PHASE_DROPPRIV      4  /* Last chance for privileged operations */
 182 #define PHASE_RUN           5
 183 #define PHASE_SHUTDOWN      6  /* About to die; delete key material, etc. */
 184 #define NR_PHASES           7
 185
 186 typedef void hook_fn(void *self, uint32_t newphase);
 187 bool_t add_hook(uint32_t phase, hook_fn *f, void *state);
 188 bool_t remove_hook(uint32_t phase, hook_fn *f, void *state);
 189
 190 /***** END of program lifetime support *****/
 191
 192 /***** MODULE support *****/
 193
 194 /* Module initialisation function type - modules export one function of
 195    this type which is called to initialise them. For dynamically loaded
 196    modules it's called "secnet_module". */
 197 typedef void (init_module)(dict_t *dict);
 198
 199 /***** END of module support *****/
 200
 201 /***** CLOSURE TYPES and interface definitions *****/
 202
 203 #define CL_PURE        0
 204 #define CL_RESOLVER    1
 205 #define CL_RANDOMSRC   2
 206 #define CL_RSAPUBKEY   3
 207 #define CL_RSAPRIVKEY  4
 208 #define CL_COMM        5
 209 #define CL_IPIF        6
 210 #define CL_LOG         7
 211 #define CL_SITE        8
 212 #define CL_TRANSFORM   9
 213 #define CL_NETLINK    10
 214 #define CL_DH         11
 215 #define CL_HASH       12
 216 #define CL_BUFFER     13
 217
 218 struct buffer_if;
 219
 220 /* PURE closure requires no interface */
 221
 222 /* RESOLVER interface */
 223
 224 /* Answers to queries are delivered to a function of this
 225    type. 'address' will be NULL if there was a problem with the query. It
 226    will be freed once resolve_answer_fn returns. It is in network byte
 227    order. */
 228 typedef void resolve_answer_fn(void *st, struct in_addr *addr);
 229 typedef bool_t resolve_request_fn(void *st, string_t name,
 230                                   resolve_answer_fn *cb, void *cst);
 231 struct resolver_if {
 232     void *st;
 233     resolve_request_fn *request;
 234 };
 235
 236 /* RANDOMSRC interface */
 237
 238 /* Return some random data. Returns TRUE for success. */
 239 typedef bool_t random_fn(void *st, uint32_t bytes, uint8_t *buff);
 240
 241 struct random_if {
 242     void *st;
 243     bool_t blocking;
 244     random_fn *generate;
 245 };
 246
 247 /* RSAPUBKEY interface */
 248
 249 typedef bool_t rsa_checksig_fn(void *st, uint8_t *data, uint32_t datalen,
 250                                string_t signature);
 251 struct rsapubkey_if {
 252     void *st;
 253     rsa_checksig_fn *check;
 254 };
 255
 256 /* RSAPRIVKEY interface */
 257
 258 typedef string_t rsa_makesig_fn(void *st, uint8_t *data, uint32_t datalen);
 259 struct rsaprivkey_if {
 260     void *st;
 261     rsa_makesig_fn *sign;
 262 };
 263
 264 /* COMM interface */
 265
 266 /* Return True if the packet was processed, and shouldn't be passed to
 267    any other potential receivers. */
 268 typedef bool_t comm_notify_fn(void *state, struct buffer_if *buf,
 269                             struct sockaddr_in *source);
 270 typedef void comm_request_notify_fn(void *commst, void *nst,
 271                                     comm_notify_fn *fn);
 272 typedef void comm_release_notify_fn(void *commst, void *nst,
 273                                     comm_notify_fn *fn);
 274 typedef bool_t comm_sendmsg_fn(void *commst, struct buffer_if *buf,
 275                                struct sockaddr_in *dest);
 276 struct comm_if {
 277     void *st;
 278     comm_request_notify_fn *request_notify;
 279     comm_release_notify_fn *release_notify;
 280     comm_sendmsg_fn *sendmsg;
 281 };
 282
 283 /* LOG interface */
 284
 285 typedef void log_msg_fn(void *st, int priority, char *message, ...);
 286 typedef void log_vmsg_fn(void *st, int priority, char *message, va_list args);
 287 struct log_if {
 288     void *st;
 289     log_msg_fn *log;
 290     log_vmsg_fn *vlog;
 291 };
 292 /* (convenience function, defined in util.c) */
 293 extern void log(struct log_if *lf, int priority, char *message, ...);
 294
 295 /* SITE interface */
 296
 297 /* Pretty much a placeholder; allows starting and stopping of processing,
 298    key expiry, etc. */
 299 typedef void site_control_fn(void *st, bool_t run);
 300 typedef uint32_t site_status_fn(void *st);
 301 struct site_if {
 302     void *st;
 303     site_control_fn *control;
 304     site_status_fn *status;
 305 };
 306
 307 /* TRANSFORM interface */
 308
 309 /* A reversable transformation. Transforms buffer in-place; may add
 310    data to start or end. Maximum amount of data to be added specified
 311    in max_start_pad and max_end_pad. (Reverse transformations decrease
 312    length, of course.)  Transformations may be key-dependent, in which
 313    case key material is passed in at initialisation time. They may
 314    also depend on internal factors (eg. time) and keep internal
 315    state. A struct transform_if only represents a particular type of
 316    transformation; instances of the transformation (eg. with
 317    particular key material) have a different C type. */
 318
 319 typedef struct transform_inst_if *transform_createinstance_fn(void *st);
 320 typedef bool_t transform_setkey_fn(void *st, uint8_t *key, uint32_t keylen);
 321 typedef void transform_delkey_fn(void *st);
 322 typedef void transform_destroyinstance_fn(void *st);
 323 /* Returns 0 for 'all is well', any other value for a problem */
 324 typedef uint32_t transform_apply_fn(void *st, struct buffer_if *buf,
 325                                     char **errmsg);
 326
 327 struct transform_inst_if {
 328     void *st;
 329     transform_setkey_fn *setkey;
 330     transform_delkey_fn *delkey;
 331     transform_apply_fn *forwards;
 332     transform_apply_fn *reverse;
 333     transform_destroyinstance_fn *destroy;
 334 };
 335
 336 struct transform_if {
 337     void *st;
 338     uint32_t max_start_pad;
 339     uint32_t max_end_pad;
 340     uint32_t keylen;
 341     transform_createinstance_fn *create;
 342 };
 343
 344 /* NETLINK interface */
 345
 346 /* Used by netlink to deliver to site, and by site to deliver to netlink.
 347    cid is the client identifier returned by netlink_regnets_fn */
 348 typedef void netlink_deliver_fn(void *st, void *cid, struct buffer_if *buf);
 349 /* site code can tell netlink when outgoing packets will be dropped,
 350    so netlink can generate appropriate ICMP */
 351 typedef void netlink_can_deliver_fn(void *st, void *cid, bool_t can_deliver);
 352 /* Register for packets from specified networks. Return value is client
 353    identifier. */
 354 typedef void *netlink_regnets_fn(void *st, struct subnet_list *networks,
 355                                  netlink_deliver_fn *deliver, void *dst,
 356                                  uint32_t max_start_pad, uint32_t max_end_pad,
 357                                  string_t client_name);
 358
 359 struct netlink_if {
 360     void *st;
 361     netlink_regnets_fn *regnets;
 362     netlink_deliver_fn *deliver;
 363     netlink_can_deliver_fn *set_delivery;
 364 };
 365
 366 /* DH interface */
 367
 368 /* Returns public key as a malloced hex string */
 369 typedef string_t dh_makepublic_fn(void *st, uint8_t *secret,
 370                                   uint32_t secretlen);
 371 /* Fills buffer (up to buflen) with shared secret */
 372 typedef void dh_makeshared_fn(void *st, uint8_t *secret,
 373                               uint32_t secretlen, string_t rempublic,
 374                               uint8_t *sharedsecret, uint32_t buflen);
 375 struct dh_if {
 376     void *st;
 377     uint32_t len; /* Approximate size of modulus in bytes */
 378     dh_makepublic_fn *makepublic;
 379     dh_makeshared_fn *makeshared;
 380 };
 381
 382 /* HASH interface */
 383
 384 typedef void *hash_init_fn(void);
 385 typedef void hash_update_fn(void *st, uint8_t const *buf, uint32_t len);
 386 typedef void hash_final_fn(void *st, uint8_t *digest);
 387 struct hash_if {
 388     uint32_t len; /* Hash output length in bytes */
 389     hash_init_fn *init;
 390     hash_update_fn *update;
 391     hash_final_fn *final;
 392 };
 393
 394 /* BUFFER interface */
 395
 396 struct buffer_if {
 397     bool_t free;
 398     string_t owner; /* Set to constant string */
 399     uint32_t flags; /* How paranoid should we be? */
 400     struct cloc loc; /* Where we were defined */
 401     uint8_t *base;
 402     uint8_t *start;
 403     uint32_t size; /* Size of buffer contents */
 404     uint32_t len; /* Total length allocated at base */
 405 };
 406
 407 #endif /* secnet_h */