resolver.c

   1 /* Name resolution using adns */
   2
   3 #include <errno.h>
   4 #include "secnet.h"
   5 #include "util.h"
   6 #ifndef HAVE_LIBADNS
   7 #error secnet requires ADNS version 1.0 or above
   8 #endif
   9 #include <adns.h>
  10 #include <arpa/inet.h>
  11 #include <string.h>
  12
  13
  14 struct adns {
  15     closure_t cl;
  16     struct resolver_if ops;
  17     struct cloc loc;
  18     adns_state ast;
  19 };
  20
  21 struct query {
  22     void *cst;
  23     int port;
  24     struct comm_if *comm;
  25     resolve_answer_fn *answer;
  26     adns_query query;
  27 };
  28
  29 static resolve_request_fn resolve_request;
  30 static bool_t resolve_request(void *sst, cstring_t name,
  31                               int port, struct comm_if *comm,
  32                               resolve_answer_fn *cb, void *cst)
  33 {
  34     struct adns *st=sst;
  35     struct query *q;
  36     int rv;
  37     const int maxlitlen=
  38 #ifdef CONFIG_IPV6
  39         ADNS_ADDR2TEXT_BUFLEN*2
  40 #else
  41         50
  42 #endif
  43         ;
  44     ssize_t l=strlen(name);
  45     if (name[0]=='[' && l<maxlitlen && l>2 && name[l-1]==']') {
  46         char trimmed[maxlitlen+1];
  47         memcpy(trimmed,name+1,l-2);
  48         trimmed[l-2]=0;
  49         struct comm_addr ca;
  50         FILLZERO(ca);
  51         ca.comm=comm;
  52         ca.ix=-1;
  53 #ifdef CONFIG_IPV6
  54         socklen_t salen=sizeof(ca.ia);
  55         rv=adns_text2addr(trimmed, port, adns_qf_addrlit_ipv4_quadonly,
  56                           &ca.ia.sa, &salen);
  57         assert(rv!=ENOSPC);
  58         if (rv) {
  59             char msg[250];
  60             snprintf(msg,sizeof(msg),"invalid address literal: %s",
  61                      strerror(rv));
  62             msg[sizeof(msg)-1]=0;
  63             cb(cst,0,0,msg);
  64         } else {
  65             cb(cst,&ca,1,0);
  66         }
  67 #else
  68         ca.ia.sin.sin_family=AF_INET;
  69         ca.ia.sin.sin_port=htons(port);
  70         if (inet_aton(trimmed,&ca.ia.sin.sin_addr))
  71             cb(cst,&ca,1,0);
  72         else
  73             cb(cst,0,0,"invalid IP address");
  74 #endif
  75         return True;
  76     }
  77
  78     q=safe_malloc(sizeof *q,"resolve_request");
  79     q->cst=cst;
  80     q->comm=comm;
  81     q->port=port;
  82     q->answer=cb;
  83
  84     rv=adns_submit(st->ast, name, adns_r_addr, 0, q, &q->query);
  85     if (rv) {
  86         Message(M_WARNING,
  87                 "resolver: failed to submit lookup for %s: %s",name,
  88                 adns_strerror(rv));
  89         free(q);
  90         return False;
  91     }
  92
  93     return True;
  94 }
  95
  96 static int resolver_beforepoll(void *sst, struct pollfd *fds, int *nfds_io,
  97                                int *timeout_io)
  98 {
  99     struct adns *st=sst;
 100     return adns_beforepoll(st->ast, fds, nfds_io, timeout_io, tv_now);
 101 }
 102
 103 static void resolver_afterpoll(void *sst, struct pollfd *fds, int nfds)
 104 {
 105     struct adns *st=sst;
 106     adns_query aq;
 107     adns_answer *ans;
 108     void *qp;
 109     struct query *q;
 110     int rv;
 111
 112     adns_afterpoll(st->ast, fds, nfds, tv_now);
 113
 114     while (True) {
 115         aq=NULL;
 116         rv=adns_check(st->ast, &aq, &ans, &qp);
 117         if (rv==0) {
 118             q=qp;
 119             if (ans->status!=adns_s_ok) {
 120                 q->answer(q->cst,NULL,0,adns_strerror(ans->status));
 121                 free(q);
 122                 free(ans);
 123             } else {
 124                 int rslot, wslot;
 125                 int ca_len=MIN(ans->nrrs,MAX_PEER_ADDRS);
 126                 struct comm_addr ca_buf[ca_len];
 127                 FILLZERO(ca_buf);
 128                 for (rslot=0, wslot=0;
 129                      rslot<ans->nrrs && wslot<ca_len;
 130                      rslot++) {
 131                     adns_rr_addr *ra=&ans->rrs.addr[rslot];
 132                     struct comm_addr *ca=&ca_buf[wslot];
 133                     ca->comm=q->comm;
 134                     /* copy fields individually so we leave holes zeroed: */
 135                     switch (ra->addr.sa.sa_family) {
 136                     case AF_INET:
 137                         assert(ra->len == sizeof(ca->ia.sin));
 138                         ca->ia.sin.sin_family=ra->addr.inet.sin_family;
 139                         ca->ia.sin.sin_addr=  ra->addr.inet.sin_addr;
 140                         ca->ia.sin.sin_port=  htons(q->port);
 141                         wslot++;
 142                         break;
 143 #ifdef CONFIG_IPV6
 144                     case AF_INET6:
 145                         assert(ra->len == sizeof(ca->ia.sin6));
 146                         ca->ia.sin6.sin6_family=ra->addr.inet6.sin6_family;
 147                         ca->ia.sin6.sin6_addr=  ra->addr.inet6.sin6_addr;
 148                         ca->ia.sin6.sin6_port=  htons(q->port);
 149                         wslot++;
 150                         break;
 151 #endif /*CONFIG_IPV6*/
 152                     default:
 153                         break;
 154                     }
 155                 }
 156                 q->answer(q->cst,ca_buf,wslot,0);
 157                 free(q);
 158                 free(ans);
 159             }
 160         } else if (rv==EAGAIN || rv==ESRCH) {
 161             break;
 162         } else {
 163             fatal("resolver_afterpoll: adns_check() returned %d",rv);
 164         }
 165     }
 166
 167     return;
 168 }
 169
 170 /* Initialise adns, using parameters supplied */
 171 static list_t *adnsresolver_apply(closure_t *self, struct cloc loc,
 172                                   dict_t *context, list_t *args)
 173 {
 174     struct adns *st;
 175     dict_t *d;
 176     item_t *i;
 177     string_t conf;
 178
 179     st=safe_malloc(sizeof(*st),"adnsresolver_apply");
 180     st->cl.description="adns";
 181     st->cl.type=CL_RESOLVER;
 182     st->cl.apply=NULL;
 183     st->cl.interface=&st->ops;
 184     st->loc=loc;
 185     st->ops.st=st;
 186     st->ops.request=resolve_request;
 187
 188     i=list_elem(args,0);
 189     if (!i || i->type!=t_dict) {
 190         cfgfatal(st->loc,"adns","first argument must be a dictionary\n");
 191     }
 192     d=i->data.dict;
 193     conf=dict_read_string(d,"config",False,"adns",loc);
 194
 195     if (conf) {
 196         if (adns_init_strcfg(&st->ast, 0, 0, conf)) {
 197             fatal_perror("Failed to initialise ADNS");
 198         }
 199     } else {
 200         if (adns_init(&st->ast, 0, 0)) {
 201             fatal_perror("Failed to initialise ADNS");
 202         }
 203     }
 204
 205     register_for_poll(st, resolver_beforepoll, resolver_afterpoll,
 206                       ADNS_POLLFDS_RECOMMENDED+5,"resolver");
 207
 208     return new_closure(&st->cl);
 209 }
 210
 211 void resolver_module(dict_t *dict)
 212 {
 213     add_closure(dict,"adns",adnsresolver_apply);
 214 }