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 <sys/socket.h>
   7 #include <netinet/in.h>
   8
   9 typedef struct adns__state *adns_state;
  10 typedef struct adns__query *adns_query;
  11
  12 typedef enum {
  13   adns_if_noenv=      0x0001, /* do not look at environment */
  14   adns_if_noerrprint= 0x0002, /* never print output to stderr */
  15   adns_if_debug=      0x0004, /* print debugging output to stderr */
  16   adns_if_noautosys=  0x0008, /* do not do full flow-of-control whenever we can */
  17 } adns_initflags;
  18
  19 typedef enum {
  20   adns_f_search=     0x0001, /* use the searchlist */
  21   adns_f_usevc=      0x0002, /* use a virtual circuit (TCP connection) */
  22   adns_f_anyquote=   0x0004,
  23 } adns_queryflags;
  24
  25 typedef enum {
  26   adns__rrttype_mask=  0x0fff,
  27   adns__qtf_deref=     0x1000, /* dereference domains and produce extra data */
  28   adns__qtf_mailconv=  0x2000, /* put @ between first and second labels */
  29   adns_r_none=              0,
  30   adns_r_a=                 1,
  31   adns_r_ns_raw=            2,
  32   adns_r_ns=                   adns_r_ns_raw|adns__qtf_deref,
  33   adns_r_cname=             5,
  34   adns_r_soa_raw=           6,
  35   adns_r_soa=                  adns_r_soa_raw|adns__qtf_mailconv,
  36   adns_r_null=             10,
  37   adns_r_ptr_raw=          12,
  38   adns_r_ptr=                  adns_r_ptr_raw|adns__qtf_deref,
  39   adns_r_hinfo=            13,
  40   adns_r_mx_raw=           15,
  41   adns_r_mx=                   adns_r_mx_raw|adns__qtf_deref,
  42   adns_r_txt=              16,
  43   adns_r_rp_raw=           17,
  44   adns_r_rp=                   adns_r_rp_raw|adns__qtf_mailconv
  45 } adns_rrtype;
  46
  47 /* In queries without qtf_anyquote, all domains must have standard
  48  * legal syntax.  In queries _with_ qtf_anyquote, domains in the query
  49  * or response may contain any characters, quoted according to
  50  * RFC1035 5.1.  On input to adns, the char* is a pointer to the
  51  * interior of a " delimited string, except that " may appear in it,
  52  * and on output, the char* is a pointer to a string which would be
  53  * legal either inside or outside " delimiters, and any characters
  54  * not usually legal in domain names will be quoted as \X
  55  * (if the character is 33-126 except \ and ") or \DDD.
  56  *
  57  * Do not ask for records containing mailboxes without
  58  * specifying qtf_mailconv or qtf_anyquote.
  59  */
  60
  61 typedef enum {
  62   adns_s_ok,
  63   adns_s_notresponding,
  64   adns_s_serverfailure,
  65   adns_s_unknownqtype,
  66   adns_s_remoteerror,
  67   adns_s_max_tempfail= 99,
  68   adns_s_nxdomain,
  69   adns_s_norecord,
  70   adns_s_invaliddomain
  71 } adns_status;
  72
  73 /* In dereferenced answers, multiple addresses show up as multiple
  74  * answers with all the dm pointers being the same.  If no
  75  * address is available (permanent failure) then INADDR_NONE is
  76  * used.
  77  */
  78
  79 typedef struct {
  80   adns_status status;
  81   char *cname; /* always NULL if query was for CNAME records */
  82   adns_rrtype type;
  83   int nrrs;
  84   union {
  85     struct in_addr inaddr[1];                                          /* a */
  86     char (*str)[1];                     /* ns_raw, cname, ptr, ptr_raw, txt */
  87     struct { char *dm; struct in_addr addr; } dmaddr;                 /* ns */
  88     struct { char *a, *b; } strpair[1];                /* hinfo, rp, rp_raw */
  89     struct { int pref; char *dm; struct in_addr addr; } intdmaddr[1]; /* mx */
  90     struct { int pref; char *str; } intstr[1]; /* mx_raw */
  91     struct {
  92       char *ns0, *rp;
  93       unsigned long serial, refresh, retry, expire, minimum;
  94     } soa[1]; /* soa, soa_raw */
  95     /* NULL is empty */
  96   } rrs;
  97 } adns_answer;
  98
  99 /* Memory management:
 100  *  adns_state and adns_query are actually pointers to malloc'd state;
 101  *  On submission questions are copied, including the owner domain;
 102  *  Answers are malloc'd as a single piece of memory.
 103  * query_io:
 104  *  Must always be non-null pointer;
 105  *  If *query_io is 0 to start with then any query may be returned;
 106  *  If *query_io is !0 adns_query then only that query may be returned.
 107  * Errors:
 108  *  Return values are 0 or an errno value;
 109  *  Seriously fatal system errors (eg, failure to create sockets,
 110  *  malloc failure, etc.) return errno values;
 111  *  Other errors (nameserver failure, timed out connections, &c)
 112  *  are returned in the status field of the answer.  If status is
 113  *  nonzero then nrrs will be 0, otherwise it will be >0.
 114  *  type will always be the type requested;
 115  *  If no (appropriate) requests are done adns_check returns EWOULDBLOCK;
 116  *  If no (appropriate) requests are outstanding adns_query and adns_wait return ESRCH;
 117  *  If malloc failure occurs during internal allocation or processing
 118  *  ands_check and _wait set *answer to 0.
 119  */
 120
 121 int adns_init(adns_state *newstate_r, adns_initflags flags);
 122
 123 int adns_synchronous(adns_state ads,
 124                      const char *owner,
 125                      adns_rrtype type,
 126                      adns_queryflags flags,
 127                      adns_answer *answer);
 128 /* Will not return EINTR. */
 129
 130 /* NB: if you set adns_if_noautosys then _submit and _check do not
 131  * make any system calls; you must use adns_callback (possibly after
 132  * adns_interest) to actually get things to happen.
 133  */
 134
 135 int adns_submit(adns_state ads,
 136                 const char *owner,
 137                 adns_rrtype type,
 138                 adns_queryflags flags,
 139                 void *context,
 140                 adns_query *query_r);
 141
 142 int adns_check(adns_state ads,
 143                adns_query *query_io,
 144                adns_answer *answer,
 145                void *context_r);
 146
 147 int adns_wait(adns_state ads,
 148               adns_query *query_io,
 149               adns_answer *answer,
 150               void *context_r);
 151 /* Might return EINTR - if so, try again */
 152
 153 void adns_cancel(adns_state ads, adns_query query);
 154
 155 int adns_finish(adns_state);
 156
 157 int adns_callback(adns_state, int maxfd, const fd_set *readfds, const fd_set *writefds,
 158                   const fd_set *exceptfds);
 159 /* Gives adns flow-of-control for a bit.  This will never block.
 160  * If maxfd == -1 then adns will check (make nonblocking system calls on)
 161  * all of its own filedescriptors; otherwise it will only use those
 162  * < maxfd and specified in the fd_set's, as if select had returned them.
 163  * Other fd's may be in the fd_sets, and will be ignored.
 164  * _callback returns how many adns fd's were in the various sets, so
 165  * you can tell if your select handling code has missed something and is going awol.
 166  */
 167
 168 void adns_interest(adns_state, int *maxfd_io, fd_set *readfds_io,
 169                    fd_set *writefds_io, fd_set *exceptfds_io,
 170                    struct timeval **tv_mod, struct timeval *tv_buf);
 171 /* Find out file descriptors adns is interested in, and when it
 172  * would like the opportunity to time something out.  If you do not plan to
 173  * block then tv_mod may be 0.  Otherwise, tv_mod may point to 0 meaning
 174  * you have no timeout of your own, in which case tv_buf must be non-null and
 175  * _interest may fill it in and set *tv_mod=tv_buf.
 176  * readfds, writefds, exceptfds and maxfd may not be 0.
 177  */
 178
 179 /* Example expected/legal calling sequences:
 180  *  adns_init
 181  *  adns_submit 1
 182  *  adns_submit 2
 183  *  adns_submit 3
 184  *  adns_wait 1
 185  *  adns_check 3 -> EWOULDBLOCK
 186  *  adns_wait 2
 187  *  adns_wait 3
 188  *  ....
 189  *  adns_finish
 190  *
 191  *  adns_init _noautosys
 192  *  loop {
 193  *   adns_interest
 194  *   select
 195  *   adns_callback
 196  *   ...
 197  *   adns_submit / adns_check
 198  *   ...
 199  *  }
 200  */
 201
 202 #endif