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

   1 /**/
   2
   3 #ifndef ADNS_H_INCLUDED
   4 #define ADNS_H_INCLUDED
   5
   6 #include <stdio.h>
   7
   8 #include <sys/socket.h>
   9 #include <netinet/in.h>
  10
  11 typedef struct adns__state *adns_state;
  12 typedef struct adns__query *adns_query;
  13 typedef const struct adns__rrtype *adns_rrtype;
  14
  15 typedef enum {
  16   adns_if_noenv=        0x0001, /* do not look at environment */
  17   adns_if_noerrprint=   0x0002, /* never print output to stderr (_debug overrides) */
  18   adns_if_noserverwarn= 0x0004, /* do not warn to stderr about duff nameservers etc */
  19   adns_if_debug=        0x0008, /* enable all output to stderr plus debug msgs */
  20   adns_if_noautosys=    0x0010, /* do not make syscalls at every opportunity */
  21 } adns_initflags;
  22
  23 typedef enum {
  24   adns_qf_search=     0x0001, /* use the searchlist */
  25   adns_qf_usevc=      0x0002, /* use a virtual circuit (TCP connection) */
  26   adns_qf_anyquote=   0x0004,
  27   adns_qf_loosecname= 0x0008, /* allow refs to CNAMEs - without, get _s_cname */
  28   adns_qf_nocname=    0x0010, /* don't follow CNAMEs, instead give _s_cname */
  29 } adns_queryflags;
  30
  31 typedef const struct adns__rrtype adns__rrtype_indicator[1];
  32
  33 extern adns__rrtype_indicator
  34   adns_r_none,
  35   adns_r_null,     adns_r_null_mf,
  36   adns_r_a,        adns_r_a_mf,
  37   adns_r_ns,       adns_r_ns_mf,      adns_r_ns_raw,
  38   adns_r_soa,      adns_r_soa_mf,     adns_r_soa_raw,
  39   adns_r_cname,    adns_r_cname_mf,
  40   adns_r_ptr,      adns_r_ptr_mf,     adns_r_ptr_raw,
  41   adns_r_hinfo,    adns_r_hinfo_mf,
  42   adns_r_mx_raw,
  43   adns_r_mx,
  44   adns_r_txt,
  45   adns_r_mx_mf,
  46   adns_r_rp_raw,
  47   adns_r_txt_mf,
  48   adns_r_rp,
  49   adns_r_rp_mf;
  50
  51 typedef enum {
  52   adns__rrt_typemask=  0x0ffff,
  53   adns__qtf_deref=     0x10000, /* dereference domains and perhaps produce extra data */
  54   adns__qtf_mail822=   0x20000, /* make mailboxes be in RFC822 rcpt field format */
  55   adns__qtf_masterfmt= 0x80000, /* convert RRs to master file format, return as str */
  56
  57   adns_r_none=               0,
  58
  59   adns_r_a=                  1,
  60   adns_r_a_mf=                  adns_r_a|adns__qtf_masterfmt,
  61
  62   adns_r_ns_raw=             2,
  63   adns_r_ns=                    adns_r_ns_raw|adns__qtf_deref,
  64   adns_r_ns_mf=                 adns_r_ns_raw|adns__qtf_masterfmt,
  65
  66   adns_r_cname=              5,
  67   adns_r_cname_mf=              adns_r_cname|adns__qtf_masterfmt,
  68
  69   adns_r_soa_raw=            6,
  70   adns_r_soa=                   adns_r_soa_raw|adns__qtf_mail822,
  71   adns_r_soa_mf=                adns_r_soa_raw|adns__qtf_masterfmt,
  72
  73   adns_r_null=              10,
  74   adns_r_null_mf=               adns_r_null|adns__qtf_masterfmt,
  75
  76   adns_r_ptr_raw=           12,
  77   adns_r_ptr=                   adns_r_ptr_raw|adns__qtf_deref,
  78   adns_r_ptr_mf=                adns_r_ptr_raw|adns__qtf_masterfmt,
  79
  80   adns_r_hinfo=             13,
  81   adns_r_hinfo_mf=              adns_r_hinfo|adns__qtf_masterfmt,
  82
  83   adns_r_mx_raw=            15,
  84   adns_r_mx=                    adns_r_mx_raw|adns__qtf_deref,
  85   adns_r_mx_mf=                 adns_r_mx_raw|adns__qtf_masterfmt,
  86
  87   adns_r_txt=               16,
  88   adns_r_txt_mf=                adns_r_txt|adns__qtf_masterfmt,
  89
  90   adns_r_rp_raw=            17,
  91   adns_r_rp=                    adns_r_rp_raw|adns__qtf_mail822,
  92   adns_r_rp_mf=                 adns_r_rp_raw|adns__qtf_masterfmt
  93
  94 } adns_rrtype;
  95
  96 /* In queries without qtf_anyquote, all domains must have standard
  97  * legal syntax.  In queries _with_ qtf_anyquote, domains in the query
  98  * or response may contain any characters, quoted according to
  99  * RFC1035 5.1.  On input to adns, the char* is a pointer to the
 100  * interior of a " delimited string, except that " may appear in it,
 101  * and on output, the char* is a pointer to a string which would be
 102  * legal either inside or outside " delimiters, and any characters
 103  * not usually legal in domain names will be quoted as \X
 104  * (if the character is 33-126 except \ and ") or \DDD.
 105  *
 106  * _qtf_anyquote is ignored for _mf queries.
 107  *
 108  * Do not ask for _raw records containing mailboxes without
 109  * specifying _qf_anyquote.
 110  */
 111
 112 typedef enum {
 113   adns_s_ok,
 114   adns_s_timeout,
 115   adns_s_unknownqtype,
 116   adns_s_nolocalmem,
 117   adns_s_allservfail,
 118   adns_s_max_tempfail= 99,
 119   adns_s_inconsistent, /* PTR gives domain whose A does not match */
 120   adns_s_cname, /* CNAME found where data eg A expected (not if _qf_loosecname) */
 121   adns_s_max_misconfig= 199,
 122   adns_s_nxdomain,
 123   adns_s_norecord,
 124   adns_s_invaliddomain
 125 } adns_status;
 126
 127 typedef struct {
 128   char *dm;
 129   adns_status astatus;
 130   int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */
 131   struct in_addr *addrs;
 132 } adns_rr_dmaddr;
 133
 134 typedef struct {
 135   char *a, *b;
 136 } adns_rr_strpair;
 137
 138 typedef struct {
 139   int i;
 140   adns_rr_dmaddr dmaddr;
 141 } adns_rr_intdmaddr;
 142
 143 typedef struct {
 144   int i;
 145   char *str;
 146 } adns_rr_intstr;
 147
 148 typedef struct {
 149   char *ns0, *rp;
 150   unsigned long serial, refresh, retry, expire, minimum;
 151 } adns_rr_soa;
 152
 153 typedef struct {
 154   adns_status status;
 155   char *cname; /* always NULL if query was for CNAME records */
 156   adns_rrtype type;
 157   int nrrs;
 158   union {
 159     struct in_addr *inaddr;        /* a */
 160     char *(*str);                  /* ns_raw, cname, ptr, ptr_raw, txt, <any>_mf */
 161     adns_rr_dmaddr *dmaddr;        /* ns */
 162     adns_rr_strpair *strpair;      /* hinfo, rp, rp_raw */
 163     adns_rr_intdmaddr *intdmaddr;  /* mx */
 164     adns_rr_intstr *intstr;        /* mx_raw */
 165     adns_rr_soa *soa;              /* soa, soa_raw */
 166     /* NULL is empty */
 167   } rrs;
 168 } adns_answer;
 169
 170 /* Memory management:
 171  *  adns_state and adns_query are actually pointers to malloc'd state;
 172  *  On submission questions are copied, including the owner domain;
 173  *  Answers are malloc'd as a single piece of memory; pointers in the
 174  *  answer struct point into further memory in the answer.
 175  * query_io:
 176  *  Must always be non-null pointer;
 177  *  If *query_io is 0 to start with then any query may be returned;
 178  *  If *query_io is !0 adns_query then only that query may be returned.
 179  * Errors:
 180  *  Return values are 0 or an errno value;
 181  *  Seriously fatal system errors (eg, failure to create sockets,
 182  *  malloc failure, etc.) return errno values;
 183  *  Other errors (nameserver failure, timed out connections, &c)
 184  *  are returned in the status field of the answer.  If status is
 185  *  nonzero then nrrs will be 0, otherwise it will be >0.
 186  *  type will always be the type requested;
 187  *  If no (appropriate) requests are done adns_check returns EWOULDBLOCK;
 188  *  If no (appropriate) requests are outstanding adns_query and adns_wait return ESRCH;
 189  *  If malloc failure occurs during internal allocation or processing
 190  *  ands_check and _wait set *answer to 0.
 191  */
 192
 193 int adns_init(adns_state *newstate_r, adns_initflags flags, FILE *diagfile/*0=>stderr*/);
 194
 195 int adns_synchronous(adns_state ads,
 196                      const char *owner,
 197                      adns_rrtype type,
 198                      adns_queryflags flags,
 199                      adns_answer **answer_r);
 200 /* Will not return EINTR. */
 201
 202 /* NB: if you set adns_if_noautosys then _submit and _check do not
 203  * make any system calls; you must use adns_callback (possibly after
 204  * adns_interest) to actually get things to happen.
 205  */
 206
 207 int adns_submit(adns_state ads,
 208                 const char *owner,
 209                 adns_rrtype type,
 210                 adns_queryflags flags,
 211                 void *context,
 212                 adns_query *query_r);
 213
 214 int adns_check(adns_state ads,
 215                adns_query *query_io,
 216                adns_answer **answer_r,
 217                void **context_r);
 218
 219 int adns_wait(adns_state ads,
 220               adns_query *query_io,
 221               adns_answer **answer_r,
 222               void **context_r);
 223 /* Might return EINTR - if so, try again */
 224
 225 void adns_cancel(adns_state ads, adns_query query);
 226
 227 int adns_finish(adns_state);
 228
 229 int adns_callback(adns_state, int maxfd, const fd_set *readfds, const fd_set *writefds,
 230                   const fd_set *exceptfds);
 231 /* Gives adns flow-of-control for a bit.  This will never block.
 232  * If maxfd == -1 then adns will check (make nonblocking system calls on)
 233  * all of its own filedescriptors; otherwise it will only use those
 234  * < maxfd and specified in the fd_set's, as if select had returned them.
 235  * Other fd's may be in the fd_sets, and will be ignored.
 236  * _callback returns how many adns fd's were in the various sets, so
 237  * you can tell if your select handling code has missed something and is going awol.
 238  *
 239  * May also return -1 if a critical syscall failed, setting errno.
 240  */
 241
 242 void adns_interest(adns_state, int *maxfd_io, fd_set *readfds_io,
 243                    fd_set *writefds_io, fd_set *exceptfds_io,
 244                    struct timeval **tv_mod, struct timeval *tv_buf);
 245 /* Find out file descriptors adns is interested in, and when it
 246  * would like the opportunity to time something out.  If you do not plan to
 247  * block then tv_mod may be 0.  Otherwise, tv_mod may point to 0 meaning
 248  * you have no timeout of your own, in which case tv_buf must be non-null and
 249  * _interest may fill it in and set *tv_mod=tv_buf.
 250  * readfds, writefds, exceptfds and maxfd may not be 0.
 251  */
 252
 253 /* Example expected/legal calling sequences:
 254  *  adns_init
 255  *  adns_submit 1
 256  *  adns_submit 2
 257  *  adns_submit 3
 258  *  adns_wait 1
 259  *  adns_check 3 -> EWOULDBLOCK
 260  *  adns_wait 2
 261  *  adns_wait 3
 262  *  ....
 263  *  adns_finish
 264  *
 265  *  adns_init _noautosys
 266  *  loop {
 267  *   adns_interest
 268  *   select
 269  *   adns_callback
 270  *   ...
 271  *   adns_submit / adns_check
 272  *   ...
 273  *  }
 274  */
 275
 276 #endif