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