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