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

   1 /*
   2  * Copyright (C)1998 Ian Jackson.
   3  * This version provided for review and comment only.
   4  *
   5  * $Id$
   6  */
   7
   8 #ifndef ADNS_H_INCLUDED
   9 #define ADNS_H_INCLUDED
  10
  11 #include <stdio.h>
  12
  13 #include <sys/socket.h>
  14 #include <netinet/in.h>
  15
  16 typedef struct adns__state *adns_state;
  17 typedef struct adns__query *adns_query;
  18
  19 typedef enum {
  20   adns_if_noenv=        0x0001, /* do not look at environment */
  21   adns_if_noerrprint=   0x0002, /* never print output to stderr (_debug overrides) */
  22   adns_if_noserverwarn= 0x0004, /* do not warn to stderr about duff nameservers etc */
  23   adns_if_debug=        0x0008, /* enable all output to stderr plus debug msgs */
  24   adns_if_noautosys=    0x0010, /* do not make syscalls at every opportunity */
  25 } adns_initflags;
  26
  27 typedef enum {
  28   adns_qf_search=     0x0001, /* use the searchlist */
  29   adns_qf_usevc=      0x0002, /* use a virtual circuit (TCP connection) */
  30   adns_qf_anyquote=   0x0004,
  31   adns_qf_loosecname= 0x0008, /* allow refs to CNAMEs - without, get _s_cname */
  32   adns_qf_nocname=    0x0010, /* don't follow CNAMEs, instead give _s_cname */
  33 } adns_queryflags;
  34
  35 typedef enum {
  36   adns__rrt_typemask=  0x0ffff,
  37   adns__qtf_deref=     0x10000, /* dereference domains and perhaps produce extra data */
  38   adns__qtf_mail822=   0x20000, /* make mailboxes be in RFC822 rcpt field format */
  39   adns__qtf_masterfmt= 0x80000, /* convert RRs to master file format, return as str */
  40
  41   adns_r_none=               0,
  42
  43   adns_r_a=                  1,
  44   adns_r_a_mf=                  adns_r_a|adns__qtf_masterfmt,
  45
  46   adns_r_ns_raw=             2,
  47   adns_r_ns=                    adns_r_ns_raw|adns__qtf_deref,
  48   adns_r_ns_mf=                 adns_r_ns_raw|adns__qtf_masterfmt,
  49
  50   adns_r_cname=              5,
  51   adns_r_cname_mf=              adns_r_cname|adns__qtf_masterfmt,
  52
  53   adns_r_soa_raw=            6,
  54   adns_r_soa=                   adns_r_soa_raw|adns__qtf_mail822,
  55   adns_r_soa_mf=                adns_r_soa_raw|adns__qtf_masterfmt,
  56
  57   adns_r_null=              10,
  58   adns_r_null_mf=               adns_r_null|adns__qtf_masterfmt,
  59
  60   adns_r_ptr_raw=           12,
  61   adns_r_ptr=                   adns_r_ptr_raw|adns__qtf_deref,
  62   adns_r_ptr_mf=                adns_r_ptr_raw|adns__qtf_masterfmt,
  63
  64   adns_r_hinfo=             13,
  65   adns_r_hinfo_mf=              adns_r_hinfo|adns__qtf_masterfmt,
  66
  67   adns_r_mx_raw=            15,
  68   adns_r_mx=                    adns_r_mx_raw|adns__qtf_deref,
  69   adns_r_mx_mf=                 adns_r_mx_raw|adns__qtf_masterfmt,
  70
  71   adns_r_txt=               16,
  72   adns_r_txt_mf=                adns_r_txt|adns__qtf_masterfmt,
  73
  74   adns_r_rp_raw=            17,
  75   adns_r_rp=                    adns_r_rp_raw|adns__qtf_mail822,
  76   adns_r_rp_mf=                 adns_r_rp_raw|adns__qtf_masterfmt
  77
  78 } adns_rrtype;
  79
  80 /* In queries without qtf_anyquote, all domains must have standard
  81  * legal syntax.  In queries _with_ qtf_anyquote, domains in the query
  82  * or response may contain any characters, quoted according to
  83  * RFC1035 5.1.  On input to adns, the char* is a pointer to the
  84  * interior of a " delimited string, except that " may appear in it,
  85  * and on output, the char* is a pointer to a string which would be
  86  * legal either inside or outside " delimiters, and any characters
  87  * not usually legal in domain names will be quoted as \X
  88  * (if the character is 33-126 except \ and ") or \DDD.
  89  *
  90  * _qtf_anyquote is ignored for _mf queries.
  91  *
  92  * Do not ask for _raw records containing mailboxes without
  93  * specifying _qf_anyquote.
  94  */
  95
  96 typedef enum {
  97   adns_s_ok,
  98   adns_s_timeout,
  99   adns_s_nolocalmem,
 100   adns_s_allservfail,
 101   adns_s_servfail,
 102   adns_s_notimplemented,
 103   adns_s_refused,
 104   adns_s_reasonunknown,
 105   adns_s_norecurse,
 106   adns_s_serverfaulty,
 107   adns_s_unknownreply,
 108   adns_s_max_tempfail= 99,
 109   adns_s_inconsistent, /* PTR gives domain whose A does not match */
 110   adns_s_cname, /* CNAME found where data eg A expected (not if _qf_loosecname) */
 111   /* fixme: implement _s_cname */
 112   adns_s_max_remotemisconfig= 199,
 113   adns_s_nxdomain,
 114   adns_s_nodata,
 115   adns_s_invaliddomain,
 116   adns_s_domaintoolong,
 117 } adns_status;
 118
 119 typedef struct {
 120   char *dm;
 121   adns_status astatus;
 122   int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */
 123   struct in_addr *addrs;
 124 } adns_rr_dmaddr;
 125
 126 typedef struct {
 127   char *a, *b;
 128 } adns_rr_strpair;
 129
 130 typedef struct {
 131   int i;
 132   adns_rr_dmaddr dmaddr;
 133 } adns_rr_intdmaddr;
 134
 135 typedef struct {
 136   int i;
 137   char *str;
 138 } adns_rr_intstr;
 139
 140 typedef struct {
 141   char *ns0, *rp;
 142   unsigned long serial, refresh, retry, expire, minimum;
 143 } adns_rr_soa;
 144
 145 typedef struct {
 146   adns_status status;
 147   char *cname; /* always NULL if query was for CNAME records */
 148   adns_rrtype type;
 149   int nrrs, rrsz;
 150   union {
 151     void *untyped;
 152     unsigned char *bytes;
 153     char *(*str);                  /* ns_raw, cname, ptr, ptr_raw, txt, <any>_mf */
 154     struct in_addr *inaddr;        /* a */
 155     adns_rr_dmaddr *dmaddr;        /* ns */
 156     adns_rr_strpair *strpair;      /* hinfo, rp, rp_raw */
 157     adns_rr_intdmaddr *intdmaddr;  /* mx */
 158     adns_rr_intstr *intstr;        /* mx_raw */
 159     adns_rr_soa *soa;              /* soa, soa_raw */
 160     /* NULL is empty */
 161   } rrs;
 162 } adns_answer;
 163
 164 /* Memory management:
 165  *  adns_state and adns_query are actually pointers to malloc'd state;
 166  *  On submission questions are copied, including the owner domain;
 167  *  Answers are malloc'd as a single piece of memory; pointers in the
 168  *  answer struct point into further memory in the answer.
 169  * query_io:
 170  *  Must always be non-null pointer;
 171  *  If *query_io is 0 to start with then any query may be returned;
 172  *  If *query_io is !0 adns_query then only that query may be returned.
 173  *  If the call is successful, *query_io, *answer_r, and *context_r
 174  *  will all be set.
 175  * Errors:
 176  *  Return values are 0 or an errno value;
 177  *  Seriously fatal system errors (eg, failure to create sockets,
 178  *  malloc failure, etc.) return errno values;
 179  *  Other errors (nameserver failure, timed out connections, &c)
 180  *  are returned in the status field of the answer.  If status is
 181  *  nonzero then nrrs will be 0, otherwise it will be >0.
 182  *  type will always be the type requested;
 183  *  If no (appropriate) requests are done adns_check returns EWOULDBLOCK;
 184  *  If no (appropriate) requests are outstanding adns_query and adns_wait return ESRCH;
 185  */
 186
 187 int adns_init(adns_state *newstate_r, adns_initflags flags, FILE *diagfile/*0=>stderr*/);
 188
 189 int adns_synchronous(adns_state ads,
 190                      const char *owner,
 191                      adns_rrtype type,
 192                      adns_queryflags flags,
 193                      adns_answer **answer_r);
 194 /* Will not return EINTR. */
 195
 196 /* NB: if you set adns_if_noautosys then _submit and _check do not
 197  * make any system calls; you must use adns_callback (possibly after
 198  * adns_interest) to actually get things to happen.
 199  */
 200
 201 int adns_submit(adns_state ads,
 202                 const char *owner,
 203                 adns_rrtype type,
 204                 adns_queryflags flags,
 205                 void *context,
 206                 adns_query *query_r);
 207
 208 int adns_check(adns_state ads,
 209                adns_query *query_io,
 210                adns_answer **answer_r,
 211                void **context_r);
 212
 213 int adns_wait(adns_state ads,
 214               adns_query *query_io,
 215               adns_answer **answer_r,
 216               void **context_r);
 217 /* Might return EINTR - if so, try again */
 218
 219 void adns_cancel(adns_state ads, adns_query query);
 220
 221 int adns_finish(adns_state);
 222
 223 int adns_callback(adns_state, int maxfd, const fd_set *readfds, const fd_set *writefds,
 224                   const fd_set *exceptfds);
 225 /* Gives adns flow-of-control for a bit.  This will never block.
 226  * If maxfd == -1 then adns will check (make nonblocking system calls on)
 227  * all of its own filedescriptors; otherwise it will only use those
 228  * < maxfd and specified in the fd_set's, as if select had returned them.
 229  * Other fd's may be in the fd_sets, and will be ignored.
 230  * _callback returns how many adns fd's were in the various sets, so
 231  * you can tell if your select handling code has missed something and is going awol.
 232  *
 233  * May also return -1 if a critical syscall failed, setting errno.
 234  */
 235
 236 void adns_interest(adns_state, int *maxfd_io, fd_set *readfds_io,
 237                    fd_set *writefds_io, fd_set *exceptfds_io,
 238                    struct timeval **tv_mod, struct timeval *tv_buf);
 239 /* Find out file descriptors adns is interested in, and when it
 240  * would like the opportunity to time something out.  If you do not plan to
 241  * block then tv_mod may be 0.  Otherwise, tv_mod may point to 0 meaning
 242  * you have no timeout of your own, in which case tv_buf must be non-null and
 243  * _interest may fill it in and set *tv_mod=tv_buf.
 244  * readfds, writefds, exceptfds and maxfd may not be 0.
 245  */
 246
 247 /* Example expected/legal calling sequences:
 248  *  adns_init
 249  *  adns_submit 1
 250  *  adns_submit 2
 251  *  adns_submit 3
 252  *  adns_wait 1
 253  *  adns_check 3 -> EWOULDBLOCK
 254  *  adns_wait 2
 255  *  adns_wait 3
 256  *  ....
 257  *  adns_finish
 258  *
 259  *  adns_init _noautosys
 260  *  loop {
 261  *   adns_interest
 262  *   select
 263  *   adns_callback
 264  *   ...
 265  *   adns_submit / adns_check
 266  *   ...
 267  *  }
 268  */
 269
 270 const char *adns_strerror(adns_status st);
 271
 272 #endif