resolver.c

   1 /* Name resolution using adns */
   2
   3 #include <errno.h>
   4 #include "secnet.h"
   5 #include <adns.h>
   6
   7 struct adns {
   8     closure_t cl;
   9     struct resolver_if ops;
  10     struct cloc loc;
  11     adns_state ast;
  12 };
  13
  14 struct query {
  15     void *cst;
  16     resolve_answer_fn *answer;
  17     adns_query query;
  18 };
  19
  20 static bool_t resolve_request(void *sst, string_t name,
  21                               resolve_answer_fn *cb, void *cst)
  22 {
  23     struct adns *st=sst;
  24     struct query *q;
  25     int rv;
  26
  27     q=safe_malloc(sizeof *q,"resolve_request");
  28     q->cst=cst;
  29     q->answer=cb;
  30
  31     rv=adns_submit(st->ast, name, adns_r_a, 0, q, &q->query);
  32
  33     return rv==0;
  34 }
  35
  36 static int resolver_beforepoll(void *sst, struct pollfd *fds, int *nfds_io,
  37                                int *timeout_io, const struct timeval *tv_now,
  38                                uint64_t *now)
  39 {
  40     struct adns *st=sst;
  41     return adns_beforepoll(st->ast, fds, nfds_io, timeout_io, tv_now);
  42 }
  43
  44 static void resolver_afterpoll(void *sst, struct pollfd *fds, int nfds,
  45                                const struct timeval *tv_now, uint64_t *now)
  46 {
  47     struct adns *st=sst;
  48     adns_query aq;
  49     adns_answer *ans;
  50     void *qp;
  51     struct query *q;
  52     int rv;
  53
  54     adns_afterpoll(st->ast, fds, nfds, tv_now);
  55
  56     while (True) {
  57         aq=NULL;
  58         rv=adns_check(st->ast, &aq, &ans, &qp);
  59         if (rv==0) {
  60             q=qp;
  61             if (ans->status!=adns_s_ok) {
  62                 q->answer(q->cst,NULL); /* Failure */
  63                 free(q);
  64                 free(ans);
  65             } else {
  66                 q->answer(q->cst,ans->rrs.inaddr);
  67                 free(q);
  68                 free(ans);
  69             }
  70         } else if (rv==EAGAIN || rv==ESRCH) {
  71             break;
  72         } else {
  73             fatal("resolver_afterpoll: adns_check() returned %d\n",rv);
  74         }
  75     }
  76
  77     return;
  78 }
  79
  80 /* Initialise adns, using parameters supplied */
  81 static list_t *adnsresolver_apply(closure_t *self, struct cloc loc,
  82                                   dict_t *context, list_t *args)
  83 {
  84     struct adns *st;
  85     dict_t *d;
  86     item_t *i;
  87     string_t conf;
  88
  89     st=safe_malloc(sizeof(*st),"adnsresolver_apply");
  90     st->cl.description="adns";
  91     st->cl.type=CL_RESOLVER;
  92     st->cl.apply=NULL;
  93     st->cl.interface=&st->ops;
  94     st->loc=loc;
  95     st->ops.st=st;
  96     st->ops.request=resolve_request;
  97
  98     i=list_elem(args,0);
  99     if (!i || i->type!=t_dict) {
 100         cfgfatal(st->loc,"adns","first argument must be a dictionary\n");
 101     }
 102     d=i->data.dict;
 103     conf=dict_read_string(d,"config",False,"adns",loc);
 104
 105     if (conf) {
 106         if (adns_init_strcfg(&st->ast, 0, 0, conf)) {
 107             fatal_perror("Failed to initialise ADNS");
 108         }
 109     } else {
 110         if (adns_init(&st->ast, 0, 0)) {
 111             fatal_perror("Failed to initialise ADNS");
 112         }
 113     }
 114
 115     register_for_poll(st, resolver_beforepoll, resolver_afterpoll,
 116                       ADNS_POLLFDS_RECOMMENDED+5,"resolver");
 117
 118     return new_closure(&st->cl);
 119 }
 120
 121 init_module resolver_module;
 122 void resolver_module(dict_t *dict)
 123 {
 124     add_closure(dict,"adns",adnsresolver_apply);
 125 }