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 (_debug overrides) */
  15   adns_if_noserverwarn= 0x0004, /* do not warn to stderr about duff nameservers etc */
  16   adns_if_debug=        0x0008, /* enable all output to stderr plus debug msgs*/
  17   adns_if_noautosys=    0x0010, /* do not make syscalls at every opportunity */
  18 } adns_initflags;
  19
  20 typedef enum {
  21   adns_f_search=     0x0001, /* use the searchlist */
  22   adns_f_usevc=      0x0002, /* use a virtual circuit (TCP connection) */
  23   adns_f_anyquote=   0x0004,
  24 } adns_queryflags;
  25
  26 typedef enum {
  27   adns__rrt_typemask=  0x0ffff,
  28   adns__qtf_deref=     0x10000, /* dereference domains and produce extra data */
  29   adns__qtf_mailconv=  0x20000, /* put @ between first and second labels */
  30   adns_r_none=               0,
  31   adns_r_a=                  1,
  32   adns_r_ns_raw=             2,
  33   adns_r_ns=                    adns_r_ns_raw|adns__qtf_deref,
  34   adns_r_cname=              5,
  35   adns_r_soa_raw=            6,
  36   adns_r_soa=                   adns_r_soa_raw|adns__qtf_mailconv,
  37   adns_r_null=              10,
  38   adns_r_ptr_raw=           12,
  39   adns_r_ptr=                   adns_r_ptr_raw|adns__qtf_deref,
  40   adns_r_hinfo=             13,
  41   adns_r_mx_raw=            15,
  42   adns_r_mx=                    adns_r_mx_raw|adns__qtf_deref,
  43   adns_r_txt=               16,
  44   adns_r_rp_raw=            17,
  45   adns_r_rp=                    adns_r_rp_raw|adns__qtf_mailconv
  46 } adns_rrtype;
  47
  48 /* In queries without qtf_anyquote, all domains must have standard
  49  * legal syntax.  In queries _with_ qtf_anyquote, domains in the query
  50  * or response may contain any characters, quoted according to
  51  * RFC1035 5.1.  On input to adns, the char* is a pointer to the
  52  * interior of a " delimited string, except that " may appear in it,
  53  * and on output, the char* is a pointer to a string which would be
  54  * legal either inside or outside " delimiters, and any characters
  55  * not usually legal in domain names will be quoted as \X
  56  * (if the character is 33-126 except \ and ") or \DDD.
  57  *
  58  * Do not ask for records containing mailboxes without
  59  * specifying qtf_mailconv or qtf_anyquote.
  60  */
  61
  62 typedef enum {
  63   adns_s_ok,
  64   adns_s_timeout,
  65   adns_s_unknownqtype,
  66   adns_s_nolocalmem,
  67   adns_s_max_tempfail= 99,
  68   adns_s_inconsistent, /* PTR gives domain whose A does not match */
  69   adns_s_badcname, /* CNAME found where actual record expected */
  70   adns_s_max_misconfig= 199;
  71   adns_s_nxdomain,
  72   adns_s_norecord,
  73   adns_s_invaliddomain
  74 } adns_status;
  75
  76 typedef struct {
  77   char *dm;
  78   adns_status astatus;
  79   int naddrs; /* temp fail => -1, perm fail => 0, s_ok => >0 */
  80   struct in_addr *addrs;
  81 } adns_dmaddr;
  82
  83 typedef struct {
  84   adns_status status;
  85   char *cname; /* always NULL if query was for CNAME records */
  86   adns_rrtype type;
  87   int nrrs;
  88   union {
  89     struct in_addr inaddr[1];                                                    /* a */
  90     char (*str)[1];                               /* ns_raw, cname, ptr, ptr_raw, txt */
  91     adns_dmaddr dmaddr[1];                                                      /* ns */
  92     struct { char *a, *b; } strpair[1];                          /* hinfo, rp, rp_raw */
  93     struct { int pref; adns_dmaddrs dmaddr; } intdmaddr[1];                     /* mx */
  94     struct { int pref; char *str; } intstr[1];                              /* mx_raw */
  95     struct {
  96       char *ns0, *rp;
  97       unsigned long serial, refresh, retry, expire, minimum;
  98     } soa[1];                                                         /* soa, soa_raw */
  99     /* NULL is empty */
 100   } rrs;
 101 } adns_answer;
 102
 103 /* Memory management:
 104  *  adns_state and adns_query are actually pointers to malloc'd state;
 105  *  On submission questions are copied, including the owner domain;
 106  *  Answers are malloc'd as a single piece of memory.
 107  * query_io:
 108  *  Must always be non-null pointer;
 109  *  If *query_io is 0 to start with then any query may be returned;
 110  *  If *query_io is !0 adns_query then only that query may be returned.
 111  * Errors:
 112  *  Return values are 0 or an errno value;
 113  *  Seriously fatal system errors (eg, failure to create sockets,
 114  *  malloc failure, etc.) return errno values;
 115  *  Other errors (nameserver failure, timed out connections, &c)
 116  *  are returned in the status field of the answer.  If status is
 117  *  nonzero then nrrs will be 0, otherwise it will be >0.
 118  *  type will always be the type requested;
 119  *  If no (appropriate) requests are done adns_check returns EWOULDBLOCK;
 120  *  If no (appropriate) requests are outstanding adns_query and adns_wait return ESRCH;
 121  *  If malloc failure occurs during internal allocation or processing
 122  *  ands_check and _wait set *answer to 0.
 123  */
 124
 125 int adns_init(adns_state *newstate_r, adns_initflags flags, FILE *diagfile/*0=>stderr*/);
 126
 127 int adns_synchronous(adns_state ads,
 128                      const char *owner,
 129                      adns_rrtype type,
 130                      adns_queryflags flags,
 131                      adns_answer **answer_r);
 132 /* Will not return EINTR. */
 133
 134 /* NB: if you set adns_if_noautosys then _submit and _check do not
 135  * make any system calls; you must use adns_callback (possibly after
 136  * adns_interest) to actually get things to happen.
 137  */
 138
 139 int adns_submit(adns_state ads,
 140                 const char *owner,
 141                 adns_rrtype type,
 142                 adns_queryflags flags,
 143                 void *context,
 144                 adns_query *query_r);
 145
 146 int adns_check(adns_state ads,
 147                adns_query *query_io,
 148                adns_answer **answer_r,
 149                void **context_r);
 150
 151 int adns_wait(adns_state ads,
 152               adns_query *query_io,
 153               adns_answer **answer_r,
 154               void **context_r);
 155 /* Might return EINTR - if so, try again */
 156
 157 void adns_cancel(adns_state ads, adns_query query);
 158
 159 int adns_finish(adns_state);
 160
 161 int adns_callback(adns_state, int maxfd, const fd_set *readfds, const fd_set *writefds,
 162                   const fd_set *exceptfds);
 163 /* Gives adns flow-of-control for a bit.  This will never block.
 164  * If maxfd == -1 then adns will check (make nonblocking system calls on)
 165  * all of its own filedescriptors; otherwise it will only use those
 166  * < maxfd and specified in the fd_set's, as if select had returned them.
 167  * Other fd's may be in the fd_sets, and will be ignored.
 168  * _callback returns how many adns fd's were in the various sets, so
 169  * you can tell if your select handling code has missed something and is going awol.
 170  */
 171
 172 void adns_interest(adns_state, int *maxfd_io, fd_set *readfds_io,
 173                    fd_set *writefds_io, fd_set *exceptfds_io,
 174                    struct timeval **tv_mod, struct timeval *tv_buf);
 175 /* Find out file descriptors adns is interested in, and when it
 176  * would like the opportunity to time something out.  If you do not plan to
 177  * block then tv_mod may be 0.  Otherwise, tv_mod may point to 0 meaning
 178  * you have no timeout of your own, in which case tv_buf must be non-null and
 179  * _interest may fill it in and set *tv_mod=tv_buf.
 180  * readfds, writefds, exceptfds and maxfd may not be 0.
 181  */
 182
 183 /* Example expected/legal calling sequences:
 184  *  adns_init
 185  *  adns_submit 1
 186  *  adns_submit 2
 187  *  adns_submit 3
 188  *  adns_wait 1
 189  *  adns_check 3 -> EWOULDBLOCK
 190  *  adns_wait 2
 191  *  adns_wait 3
 192  *  ....
 193  *  adns_finish
 194  *
 195  *  adns_init _noautosys
 196  *  loop {
 197  *   adns_interest
 198  *   select
 199  *   adns_callback
 200  *   ...
 201  *   adns_submit / adns_check
 202  *   ...
 203  *  }
 204  */
 205
 206 #endif