mdw@git.distorted.org.uk Git - adns/blob - src/internal.h

   1 /**/
   2
   3 #ifndef ADNS_INTERNAL_H_INCLUDED
   4 #define ADNS_INTERNAL_H_INCLUDED
   5
   6 #define PRINTFFORMAT(a,b) __attribute__((format(printf,a,b)))
   7 typedef unsigned char byte;
   8
   9 #include <stdarg.h>
  10 #include <assert.h>
  11 #include <unistd.h>
  12
  13 #include <sys/time.h>
  14
  15 #include "adns.h"
  16
  17 /* Configuration and constants */
  18
  19 #define MAXSERVERS 5
  20 #define UDPMAXRETRIES /*15*/5
  21 #define UDPRETRYMS 2000
  22 #define TCPMS 30000
  23 #define LOCALRESOURCEMS 20
  24
  25 #define DNS_PORT 53
  26 #define DNS_MAXUDP 512
  27 #define DNS_MAXDOMAIN 255
  28 #define DNS_HDRSIZE 12
  29 #define DNS_CLASS_IN 1
  30
  31 typedef enum {
  32   rcode_noerror,
  33   rcode_formaterror,
  34   rcode_servfail,
  35   rcode_nxdomain,
  36   rcode_notimp,
  37   rcode_refused
  38 } dns_rcode;
  39
  40 /* Shared data structures */
  41
  42 typedef union {
  43   adns_status status;
  44   char *cp;
  45   adns_rrtype type;
  46   int i;
  47   struct in_addr ia;
  48   unsigned long ul;
  49 } rr_align;
  50
  51 typedef struct {
  52   int used, avail;
  53   byte *buf;
  54 } vbuf;
  55
  56 typedef union {
  57   void *ext;
  58   int dmaddr_index;
  59 } qcontext;
  60
  61 typedef struct {
  62   adns_rrtype type;
  63   const char *name;
  64   int rrsz;
  65
  66   adns_status (*parse)(adns_state ads, adns_query qu, int serv,
  67                        const byte *dgram, int dglen, int cbyte, int max,
  68                        void *store_r);
  69   /* Parse one RR, in dgram of length dglen, starting at cbyte and
  70    * extending until at most max.
  71    *
  72    * The RR should be stored at *store_r, of length qu->typei->rrsz.
  73    *
  74    * If there is an overrun which might indicate truncation, it should set
  75    * *rdstart to -1; otherwise it may set it to anything else positive.
  76    */
  77
  78   void (*makefinal)(adns_state ads, adns_query qu, void *data);
  79   /* Change memory management of *data.
  80    * Previously, used alloc_interim, now use alloc_final.
  81    */
  82 } typeinfo;
  83
  84 typedef struct allocnode {
  85   struct allocnode *next;
  86 } allocnode;
  87
  88 union maxalign {
  89   byte d[1];
  90   struct in_addr ia;
  91   long l;
  92   void *p;
  93   void (*fp)(void);
  94   union maxalign *up;
  95 } data;
  96
  97 struct adns__query {
  98   enum { query_udp, query_tcpwait, query_tcpsent, query_child, query_done } state;
  99   adns_query back, next, parent;
 100   struct { adns_query head, tail; } children;
 101   struct { adns_query back, next; } siblings;
 102   struct allocnode *allocations;
 103   int interim_allocd;
 104   void *final_allocspace;
 105
 106   const typeinfo *typei;
 107   char *query_dgram;
 108   int query_dglen;
 109
 110   vbuf vb;
 111   /* General-purpose messing-about buffer.
 112    * Wherever a `big' interface is crossed, this may be corrupted/changed
 113    * unless otherwise specified.
 114    */
 115
 116   adns_answer *answer;
 117   /* This is allocated when a query is submitted, to avoid being unable
 118    * to relate errors to queries if we run out of memory.  During
 119    * query processing status, rrs is 0.  cname is set if
 120    * we found a cname (this corresponds to cname_dgram in the query
 121    * structure).  type is set from the word go.  nrrs and rrs
 122    * are set together, when we find how many rrs there are.
 123    */
 124
 125   byte *cname_dgram;
 126   int cname_dglen, cname_begin;
 127
 128   int id, flags, udpretries;
 129   int udpnextserver;
 130   unsigned long udpsent, tcpfailed; /* bitmap indexed by server */
 131   struct timeval timeout;
 132   qcontext context;
 133
 134   /* Possible states:
 135    *
 136    *  state   Queue   child  id   nextudpserver  sentudp     failedtcp
 137    *
 138    *  udp     NONE    null   >=0  0              zero        zero
 139    *  udp     timew   null   >=0  any            nonzero     zero
 140    *  udp     NONE    null   >=0  any            nonzero     zero
 141    *
 142    *  tcpwait timew   null   >=0  irrelevant     zero        any
 143    *  tcpsent timew   null   >=0  irrelevant     zero        any
 144    *
 145    *  child   childw  set    >=0  irrelevant     irrelevant  irrelevant
 146    *  done    output  null   -1   irrelevant     irrelevant  irrelevant
 147    *
 148    *                          +------------------------+
 149    *             START -----> |      udp/NONE          |
 150    *                          +------------------------+
 151    *                         /                       |\  \
 152    *        too big for UDP /             UDP timeout  \  \ send via UDP
 153    *        do this ASAP!  /              more retries  \  \   do this ASAP!
 154    *                     |_                  desired     \  _|
 155    *              +---------------+                     +-----------+
 156    *              | tcpwait/timew | ____                | udp/timew |
 157    *              +---------------+     \               +-----------+
 158    *                    |  ^             |                 | |
 159    *     TCP conn'd;    |  | TCP died    |                 | |
 160    *     send via TCP   |  | more        |     UDP timeout | |
 161    *     do this ASAP!  |  | servers     |      no more    | |
 162    *                    v  | to try      |      retries    | |
 163    *              +---------------+      |      desired    | |
 164    *              | tcpsent/timew | ____ |                 | |
 165    *              +---------------+     \|                 | |
 166    *                  \   \ TCP died     | TCP             | |
 167    *                   \   \ no more     | timeout         / |
 168    *                    \   \ servers    |                /  |
 169    *                     \   \ to try    |               /   |
 170    *                  got \   \          v             |_    / got
 171    *                 reply \   _| +------------------+      / reply
 172    *                        \     | done/output FAIL |     /
 173    *                         \    +------------------+    /
 174    *                          \                          /
 175    *                           _|                      |_
 176    *                             (..... got reply ....)
 177    *                              /                   \
 178    *        need child query/ies /                     \ no child query
 179    *                            /                       \
 180    *                          |_                         _|
 181    *                +--------------+                   +----------------+
 182    *                | child/childw | ----------------> | done/output OK |
 183    *                +--------------+  children done    +----------------+
 184    */
 185 };
 186
 187 struct adns__state {
 188   adns_initflags iflags;
 189   FILE *diagfile;
 190   struct { adns_query head, tail; } timew, childw, output;
 191   int nextid, udpsocket, tcpsocket;
 192   vbuf tcpsend, tcprecv;
 193   int nservers, tcpserver;
 194   enum adns__tcpstate { server_disconnected, server_connecting, server_ok } tcpstate;
 195   struct timeval tcptimeout;
 196   struct server {
 197     struct in_addr addr;
 198   } servers[MAXSERVERS];
 199 };
 200
 201 /* From setup.c: */
 202
 203 void adns__vdiag(adns_state ads, const char *pfx, adns_initflags prevent,
 204                  int serv, adns_query qu, const char *fmt, va_list al);
 205
 206 void adns__debug(adns_state ads, int serv, adns_query qu,
 207                  const char *fmt, ...) PRINTFFORMAT(4,5);
 208 void adns__warn(adns_state ads, int serv, adns_query qu,
 209                 const char *fmt, ...) PRINTFFORMAT(4,5);
 210 void adns__diag(adns_state ads, int serv, adns_query qu,
 211                 const char *fmt, ...) PRINTFFORMAT(4,5);
 212
 213 int adns__vbuf_ensure(vbuf *vb, int want);
 214 int adns__vbuf_appendstr(vbuf *vb, const char *data);
 215 int adns__vbuf_append(vbuf *vb, const byte *data, int len);
 216 /* 1=>success, 0=>realloc failed */
 217 void adns__vbuf_appendq(vbuf *vb, const byte *data, int len);
 218 void adns__vbuf_init(vbuf *vb);
 219 void adns__vbuf_free(vbuf *vb);
 220
 221 int adns__setnonblock(adns_state ads, int fd); /* => errno value */
 222
 223 /* From submit.c: */
 224
 225 int adns__internal_submit(adns_state ads, adns_query *query_r,
 226                           adns_rrtype type, vbuf *qumsg_vb, int id,
 227                           adns_queryflags flags, struct timeval now,
 228                           adns_status failstat, const qcontext *ctx);
 229 /* Submits a query (for internal use, called during external submits).
 230  *
 231  * The new query is returned in *query_r, or we return adns_s_nomemory.
 232  *
 233  * The query datagram should already have been assembled in qumsg_vb;
 234  * the memory for it is _taken over_ by this routine whether it
 235  * succeeds or fails (if it succeeds, the vbuf is reused for qu->vb).
 236  *
 237  * If failstat is nonzero then if we are successful in creating the query
 238  * it is immediately failed with code failstat (but _submit still succeds).
 239  *
 240  * ctx is copied byte-for-byte into the query.
 241  */
 242
 243 void *adns__alloc_interim(adns_query qu, size_t sz);
 244 /* Allocates some memory, and records which query it came from
 245  * and how much there was.
 246  *
 247  * If an error occurs in the query, all its memory is simply freed.
 248  *
 249  * If the query succeeds, one large buffer will be made which is
 250  * big enough for all these allocations, and then adns__alloc_final
 251  * will get memory from this buffer.
 252  *
 253  * _alloc_interim can fail, in which case it will fail the query too,
 254  * so nothing more need be done with it.
 255  */
 256
 257 void *adns__alloc_final(adns_query qu, size_t sz);
 258 /* Cannot fail.
 259  */
 260
 261 void adns__makefinal_block(adns_query qu, void **blpp, size_t sz);
 262 void adns__makefinal_str(adns_query qu, char **strp);
 263
 264 /* From query.c: */
 265
 266 void adns__query_udp(adns_state ads, adns_query qu, struct timeval now);
 267 void adns__query_tcp(adns_state ads, adns_query qu, struct timeval now);
 268 adns_status adns__mkquery(adns_state ads, vbuf *vb,
 269                           const char *owner, int ol, int *id_r,
 270                           const typeinfo *typei, adns_queryflags flags);
 271 /* Assembles a query packet in vb, and returns id at *id_r. */
 272
 273 void adns__query_ok(adns_state ads, adns_query qu);
 274 void adns__query_fail(adns_state ads, adns_query qu, adns_status stat);
 275
 276 void adns__reset_cnameonly(adns_state ads, adns_query qu);
 277 /* Resets all of the memory management stuff etc. to
 278  * take account of only the CNAME.  Used when we find an error somewhere
 279  * and want to just report the error (with perhaps CNAME info), and also
 280  * when we're halfway through RRs in a datagram and discover that we
 281  * need to retry the query.
 282  */
 283
 284 /* From reply.c: */
 285
 286 void adns__procdgram(adns_state ads, const byte *dgram, int len,
 287                      int serv, struct timeval now);
 288
 289 /* From types.c: */
 290
 291 const typeinfo *adns__findtype(adns_rrtype type);
 292
 293 /* From parse.c: */
 294
 295 typedef struct {
 296   adns_state ads;
 297   int serv;
 298   const byte *dgram;
 299   int dglen, max, cbyte, namelen;
 300   int *dmend_rlater, *namelen_rlater;
 301 } findlabel_state;
 302
 303 void adns__findlabel_start(findlabel_state *fls,
 304                            adns_state ads, int serv,
 305                            const byte *dgram, int dglen, int max,
 306                            int dmbegin, int *dmend_rlater);
 307 /* Finds labels in a domain in a datagram.
 308  *
 309  * Call this routine first.
 310  * endpoint_rlater may be null.
 311  */
 312
 313 adns_status adns__findlabel_next(findlabel_state *fls,
 314                                  int *lablen_r, int *labstart_r);
 315 /* Then, call this one repeatedly.
 316  *
 317  * It will return adns_s_ok if all is well, and tell you the length
 318  * and start of successive labels.  labstart_r may be null, but
 319  * lablen_r must not be.
 320  *
 321  * After the last label, it will return with *lablen_r zero.
 322  * Do not then call it again; instead, just throw away the findlabel_state.
 323  *
 324  * *dmend_rlater will have been set to point to the next part of
 325  * the datagram after the label (or after the uncompressed part,
 326  * if compression was used).  *namelen_rlater will have been set
 327  * to the length of the domain name (total length of labels plus
 328  * 1 for each intervening dot).
 329  *
 330  * If the datagram appears to be truncated, *lablen_r will be -1.
 331  * *dmend_rlater, *labstart_r and *namelen_r may contain garbage.
 332  * Do not call _next again.
 333  *
 334  * There may also be errors, in which case *dmend_rlater,
 335  * *namelen_rlater, *lablen_r and *labstart_r may contain garbage.
 336  * Do not then call findlabel_next again.
 337  */
 338
 339 adns_status adns__parse_domain(adns_state ads, int serv, vbuf *vb,
 340                                const byte *dgram, int dglen,
 341                                int *cbyte_io, int max);
 342 /* vb must already have been initialised; it will be reset if necessary.
 343  * If there is truncation, vb->used will be set to 0; otherwise
 344  * (if there is no error) vb will be null-terminated.
 345  * If there is an error vb and *cbyte_io may be left indeterminate.
 346  */
 347
 348 adns_status adns__findrr(adns_state ads, int serv,
 349                          const byte *dgram, int dglen, int *cbyte_io,
 350                          int *type_r, int *class_r, int *rdlen_r, int *rdstart_r,
 351                          const byte *eo_dgram, int eo_dglen, int eo_cbyte,
 352                          int *eo_matched_r);
 353   /* Finds the extent and some of the contents of an RR in a datagram
 354    * and does some checks.  The datagram is *dgram, length dglen, and
 355    * the RR starts at *cbyte_io (which is updated afterwards to point
 356    * to the end of the RR).
 357    *
 358    * The type, class and RRdata length and start are returned iff
 359    * the corresponding pointer variables are not null.  type_r and
 360    * class_r may not be null.
 361    *
 362    * If the caller thinks they know what the owner of the RR ought to
 363    * be they can pass in details in eo_*: this is another (or perhaps
 364    * the same datagram), and a pointer to where the putative owner
 365    * starts in that datagram.  In this case *eo_matched_r will be set
 366    * to 1 if the datagram matched or 0 if it did not.  Either
 367    * both eo_dgram and eo_matched_r must both be non-null, or they
 368    * must both be null (in which case eo_dglen and eo_cbyte will be ignored).
 369    * The eo datagram and contained owner domain MUST be valid and
 370    * untruncated.
 371    *
 372    * If there is truncation then *type_r will be set to -1 and
 373    * *cbyte_io, *class_r, *rdlen_r, *rdstart_r and *eo_matched_r will be
 374    * undefined.
 375    *
 376    * If an error is returned then *type_r will be undefined too.
 377    */
 378
 379 int vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len);
 380
 381 /* From event.c: */
 382
 383 void adns__tcp_broken(adns_state ads, const char *what, const char *why);
 384 void adns__tcp_tryconnect(adns_state ads, struct timeval now);
 385 void adns__autosys(adns_state ads, struct timeval now);
 386
 387 /* Useful static inline functions: */
 388
 389 static inline void timevaladd(struct timeval *tv_io, long ms) {
 390   struct timeval tmp;
 391   assert(ms>=0);
 392   tmp= *tv_io;
 393   tmp.tv_usec += (ms%1000)*1000000;
 394   tmp.tv_sec += ms/1000;
 395   if (tmp.tv_usec >= 1000000) { tmp.tv_sec++; tmp.tv_usec -= 1000; }
 396   *tv_io= tmp;
 397 }
 398
 399 static inline int ctype_whitespace(int c) { return c==' ' || c=='\n' || c=='\t'; }
 400 static inline int ctype_digit(int c) { return c>='0' && c<='9'; }
 401 static inline int ctype_alpha(int c) {
 402   return (c >= 'a' && c <= 'z') || (c >= 'A' || c <= 'Z');
 403 }
 404
 405 /* Useful macros */
 406
 407 #define MEM_ROUND(sz) \
 408   (( ((sz)+sizeof(union maxalign)-1) / sizeof(union maxalign) ) \
 409    * sizeof(union maxalign) )
 410
 411 #define LIST_INIT(list) ((list).head= (list).tail= 0)
 412
 413 #define LIST_UNLINK_PART(list,node,part) \
 414   do { \
 415     if ((node)->back) (node)->back->part next= (node)->part next; \
 416       else                        (list).head= (node)->part next; \
 417     if ((node)->next) (node)->next->part back= (node)->part back; \
 418       else                        (list).tail= (node)->part back; \
 419   } while(0)
 420
 421 #define LIST_LINK_TAIL_PART(list,node,part) \
 422   do { \
 423     (node)->part back= 0; \
 424     (node)->part next= (list).tail; \
 425     if ((list).tail) (list).tail->part back= (node); else (list).part head= (node); \
 426     (list).tail= (node); \
 427   } while(0)
 428
 429 #define LIST_UNLINK(list,node) LIST_UNLINK_PART(list,node,)
 430 #define LIST_LINK_TAIL(list,node) LIST_LINK_TAIL_PART(list,node,)
 431
 432 #define GETIL_B(cb) (dgram[(cb)++])
 433 #define GET_B(cb,tv) ((tv)= GETIL_B((cb)))
 434 #define GET_W(cb,tv) ((tv)=0, (tv)|=(GETIL_B((cb))<<8), (tv)|=GETIL_B(cb), (tv))
 435
 436 #endif