[adns] / src / reply.c

/**/

#include "internal.h"

static void cname_recurse(adns_state ads, adns_query qu, adns_queryflags xflags) {
  abort(); /* FIXME */
}
    
void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
		     int serv, struct timeval now) {
  int cbyte, rrstart, wantedrrs, rri, foundsoa, foundns;
  int id, f1, f2, qdcount, ancount, nscount, arcount, flg_ra, flg_rd, flg_tc, opcode;
  int rrtype, rrclass, rdlength, rdstart, ownermatched, ownerstart;
  int anstart, nsstart, arstart;
  int currentrrs;
  adns_query qu, nqu;
  dns_rcode rcode;
  adns_status st;
  vbuf vb;
#error init and free vb properly
  
  if (dglen<DNS_HDRSIZE) {
    adns__diag(ads,serv,"received datagram too short for message header (%d)",dglen);
    return;
  }
  GET_W(cbyte,id);
  GET_B(cbyte,f1);
  GET_B(cbyte,f2);
  GET_W(cbyte,qdcount);
  GET_W(cbyte,ancount);
  GET_W(cbyte,nscount);
  GET_W(cbyte,arcount);
  assert(cbyte == DNS_HDRSIZE);

  flg_qr= f1&0x80;
  opcode= (f1&0x78)>>3;
  flg_tc= f1&0x20;
  flg_rd= f1&0x01;
  flg_ra= f2&0x80;
  rcode= (f1&0x0f);

  if (flg_qr) {
    adns__diag(ads,serv,"server sent us a query, not a response");
    return;
  }
  if (opcode) {
    adns__diag(ads,serv,"server sent us unknown opcode %d (wanted 0=QUERY)",opcode);
    return;
  }
  if (!qdcount) {
    adns__diag(ads,serv,"server sent reply without quoting our question");
    return;
  } else if (qdcount>1) {
    adns__diag(ads,serv,"server claimed to answer %d questions with one message",
	       qdcount);
    return;
  }
  for (qu= ads->timew.head; qu; qu= nqu) {
    nqu= qu->next;
    if (qu->id != id) continue;
    if (dglen < qu->querylen) continue;
    if (memcmp(qu->querymsg+DNS_HDRSIZE,dgram+DNS_HDRSIZE,qu->querylen-DNS_HDRSIZE))
      continue;
    break;
  }
  assert(qu->cnameoff == -1);
  anstart= qu->querylen;
  if (!qu) {
    adns__debug(ads,serv,"reply not found (id=%02x)",id);
    return;
  }

  LIST_UNLINK(ads->timew,qu);
  /* We're definitely going to do something with this query now */
  
  switch (rcode) {
  case rcode_noerror:
  case rcode_nxdomain:
    break;
  case rcode_formaterror:
    adns__warn(ads,serv,qu,"server cannot understand our query (Format Error)");
    adns__query_fail(ads,qu,adns_s_serverfaulty);
    return;
  case rcode_servfail:
    adns__query_fail(ads,qu,adns_s_servfail);
    return;
  case rcode_notimp:
    adns__warn(ads,serv,qu,"server claims not to implement our query");
    adns__query_fail(ads,qu,adns_s_notimplemented);
    return;
  case rcode_refused:
    adns__warn(ads,serv,qu,"server refused our query");
    adns__query_fail(ads,qu,adns_s_refused);
    return;
  default:
    adns__warn(ads,serv,qu,"server gave unknown response code %d",rcode);
    adns__query_fail(ads,qu,adns_s_reasonunknown);
    return;
  }

  /* Now, take a look at the answer section, and see if it is complete.
   * If it has any CNAMEs we stuff them in the answer.
   */
  wantedrrs= 0;
  for (rri= 0; rri<ancount; rri++) {
    rrstart= cbyte;
    if (qu->cname_dgram >= 0) {
      st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
		       &rrtype,&rrclass,&rdlength,&rdstart,
		       qu->cname_dgram,qu->cname_dglen,qu->cname_begin, &ownermatched);
    } else {
      st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
		       &rrtype,&rrclass,&rdlength,&rdstart,
		       qu->querymsg,qu->querylen,DNS_HDRSIZE, &ownermatched);
    }
    if (st) adns__query_fail(ads,qu,st);
    if (rrtype == -1) goto x_truncated;

    if (rrclass != DNS_CLASS_IN) {
      adns__diag(ads,serv,qu,"ignoring answer RR with wrong class %d (expected IN=%d)",
		 rrclass,DNS_CLASS_IN);
      continue;
    }
    if (!ownermatched) {
      if (ads->iflags & adns_if_debug) {
	adns__debug(ads,serv,qu,"ignoring RR with an unexpected owner %s",
		    adns__diag_domain(ads,serv,&vb,qu->flags,
				      dgram,dglen,rrstart,dglen));
      }
      continue;
    }
    if (rrtype == adns_r_cname &&
	(qu->typei->type & adns__rrt_typemask) != adns_r_cname) {
      if (!qu->cname_str) { /* Ignore second and subsequent CNAMEs */
	qu->cname_begin= rdstart;
	qu->cname_dgram= dgram;
	qu->cname_dglen= dglen;
	st= adns__parse_domain(ads,serv,&vb,qu->flags,
			       dgram,dglen, &rdstart,rdstart+rdlength);
	if (!vb.used) goto x_truncated;
	if (st) { adns__query_fail(ads,qu,st); return; }
	qu->cname_str= adns__vbuf_extractstring(&vb);
	/* If we find the answer section truncated after this point we restart
	 * the query at the CNAME; if beforehand then we obviously have to use
	 * TCP.  If there is no truncation we can use the whole answer if
	 * it contains the relevant info.
	 */
      } else {
	adns__debug(ads,serv,qu,"ignoring duplicate CNAME (%s, as well as %s)",
		    adns__diag_domain(ads,serv,&vb,qu->flags,
				      dgram,dglen, rdstart,rdstart+rdlength),
		    qu->cname_str);
      }
    } else if (rrtype == (qu->typei->type & adns__rrt_typemask)) {
      wantedrrs++;
    } else {
      adns__debug(ads,serv,qu,"ignoring answer RR with irrelevant type %d",rrtype);
    }
  }

  /* If we got here then the answer section is intact. */
  nsstart= cbyte;

  if (!wantedrrs) {
    /* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */
    
    if (rcode == rcode_nxdomain) {
      adns__query_finish(ads,qu,adns_s_nxdomain);
      return;
    }

    /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */
    foundsoa= 0; foundns= 0;
    for (rri= 0; rri<nscount; rri++) {
      rrstart= cbyte;
      st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
		       &rrtype,&rrclass,&rdlength,&rdstart,
		       0,0,0,0);
      if (st) { adns__query_fail(ads,qu,st); return; }
      if (rrtype==-1) goto x_truncated;
      if (rrclass != DNS_CLASS_IN) {
	adns__diag(ads,serv,qu,
		   "ignoring authority RR with wrong class %d (expected IN=%d)",
		   rrclass,DNS_CLASS_IN);
	continue;
      }
      if (rrtype == adns_r_soa_raw) { foundsoa= 1; break; }
      else if (rrtype == adns_r_ns_raw) { foundns= 1; }
    }

    if (foundsoa || !foundns) {
      /* Aha !  A NODATA response, good. */
      adns__query_finish(ads,qu,adns_s_nodata);
      return;
    }

    /* Now what ?  No relevant answers, no SOA, and at least some NS's.
     * Looks like a referral.  Just one last chance ... if we came across
     * a CNAME in this datagram then we should probably do our own CNAME
     * lookup now in the hope that we won't get a referral again.
     */
    if (qu->cname_dgram == dgram) { cname_recurse(ads,qu,0); return; }

    /* Bloody hell, I thought we asked for recursion ? */
    if (flg_rd) {
      adns__diag(ads,serv,qu,"server thinks we didn't ask for recursive lookup");
    }
    if (!flg_ra) {
      adns__diag(ads,serv,qu,"server is not willing to do recursive lookups for us");
      adns__query_fail(ads,qu,adns_s_norecurse);
    } else {
      adns__diag(ads,serv,qu,"server claims to do recursion, but gave us a referral");
      adns__query_fail(ads,qu,adns_s_serverfaulty);
    }
    return;
  }

  /* Now, we have some RRs which we wanted. */

  if (!adns__vbuf_ensure(&qu->ansbuf,qu->typei->rrsz*wantedrrs)) {
    adns__query_fail(ads,qu,adns_s_nolocalmem);
    return;
  }

  cbyte= anstart;
  currentrrs= 0;
  arstart= -1;
  qu->ansbuf.used= 0;
  for (rri=0; rri<ancount; rri++) {
    if (qu->cname_dgram >= 0) {
      st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
		       &rrtype,&rrclass,&rdlength,&rdstart,
		       qu->cname_dgram,qu->cname_dglen,qu->cname_begin, &ownermatched);
    } else {
      st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
		       &rrtype,&rrclass,&rdlength,&rdstart,
		       qu->querymsg,qu->querylen,DNS_HDRSIZE, &ownermatched);
    }
    assert(!st); assert(rrtype != -1);
    if (rrclass != DNS_CLASS_IN ||
	rrtype != (qu->typei->type & adns__rrt_typemask) ||
	!ownermatched)
      continue;
    assert(currentrrs<wantedrrs);
    qu->ansbuf.used += quj->typei->rrsz;
    st= qu->typei->parse(ads,qu,serv,&vb,
			 dgram,dglen, &rdstart,rdstart+rdlength,
			 (void*)(qu->ansbuf.buf+qu->ansbuf.used));
    if (st) { adns__query_fail(ads,qu,st); return; }
    if (rdstart==-1) goto x_truncated;
  }

  /* This may have generated some child queries ... */
  if (qu->children.head) {
    qu->state= query_child;
    LIST_LINK_TAIL(ads->childw,qu);
    return;
  }

  adns__query_finish(ads,qu,adns_s_ok);
  return;

x_truncated:
  if (!flg_tc) {
    adns__diag(ads,serv,qu,"server sent datagram which points outside itself");
    adns__query_fail(ads,qu,adns_s_serverfaulty);
    return;
  }
  if (qu->cname_dgram) { cname_recurse(ads,qu,adns_qf_usevc); return; }
  ans= (adns_answer*)qu->ans.buf;
  ans->nrrs= 0;
  qu->ans.used= sizeof(adns_answer);
  qu->flags |= adns_qf_usevc;
  adns__query_udp(ads,qu,now);
}
Commit	Line	Data
4353a5c4	1	/**/
	2
	3	#include "internal.h"
	4
98a3f706	5	static void cname_recurse(adns_state ads, adns_query qu, adns_queryflags xflags) {
98a3f706	6	abort(); /* FIXME */
b9de380c	7	}
b9de380c	8
98a3f706	9	void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
	10	int serv, struct timeval now) {
	11	int cbyte, rrstart, wantedrrs, rri, foundsoa, foundns;
31144a72	12	int id, f1, f2, qdcount, ancount, nscount, arcount, flg_ra, flg_rd, flg_tc, opcode;
98a3f706	13	int rrtype, rrclass, rdlength, rdstart, ownermatched, ownerstart;
	14	int anstart, nsstart, arstart;
	15	int currentrrs;
	16	adns_query qu, nqu;
	17	dns_rcode rcode;
b9de380c	18	adns_status st;
31144a72	19	vbuf vb;
31144a72	20	#error init and free vb properly
ec477b9e	21
98a3f706	22	if (dglen<DNS_HDRSIZE) {
98a3f706	23	adns__diag(ads,serv,"received datagram too short for message header (%d)",dglen);
ec477b9e	24	return;
ec477b9e	25	}
b9de380c	26	GET_W(cbyte,id);
	27	GET_B(cbyte,f1);
	28	GET_B(cbyte,f2);
	29	GET_W(cbyte,qdcount);
	30	GET_W(cbyte,ancount);
	31	GET_W(cbyte,nscount);
	32	GET_W(cbyte,arcount);
98a3f706	33	assert(cbyte == DNS_HDRSIZE);
ec477b9e	34
31144a72	35	flg_qr= f1&0x80;
31144a72	36	opcode= (f1&0x78)>>3;
98a3f706	37	flg_tc= f1&0x20;
31144a72	38	flg_rd= f1&0x01;
0ba0614a	39	flg_ra= f2&0x80;
31144a72	40	rcode= (f1&0x0f);
0ba0614a	41
31144a72	42	if (flg_qr) {
ec477b9e	43	adns__diag(ads,serv,"server sent us a query, not a response");
	44	return;
	45	}
31144a72	46	if (opcode) {
31144a72	47	adns__diag(ads,serv,"server sent us unknown opcode %d (wanted 0=QUERY)",opcode);
ec477b9e	48	return;
	49	}
	50	if (!qdcount) {
	51	adns__diag(ads,serv,"server sent reply without quoting our question");
	52	return;
	53	} else if (qdcount>1) {
	54	adns__diag(ads,serv,"server claimed to answer %d questions with one message",
	55	qdcount);
	56	return;
	57	}
98a3f706	58	for (qu= ads->timew.head; qu; qu= nqu) {
ec477b9e	59	nqu= qu->next;
ec477b9e	60	if (qu->id != id) continue;
98a3f706	61	if (dglen < qu->querylen) continue;
98a3f706	62	if (memcmp(qu->querymsg+DNS_HDRSIZE,dgram+DNS_HDRSIZE,qu->querylen-DNS_HDRSIZE))
b9de380c	63	continue;
ec477b9e	64	break;
ec477b9e	65	}
98a3f706	66	assert(qu->cnameoff == -1);
b9de380c	67	anstart= qu->querylen;
ec477b9e	68	if (!qu) {
	69	adns__debug(ads,serv,"reply not found (id=%02x)",id);
	70	return;
	71	}
98a3f706	72
	73	LIST_UNLINK(ads->timew,qu);
	74	/* We're definitely going to do something with this query now */
	75
b9de380c	76	switch (rcode) {
	77	case rcode_noerror:
	78	case rcode_nxdomain:
ec477b9e	79	break;
b9de380c	80	case rcode_formaterror:
31144a72	81	adns__warn(ads,serv,qu,"server cannot understand our query (Format Error)");
ec477b9e	82	adns__query_fail(ads,qu,adns_s_serverfaulty);
ec477b9e	83	return;
98a3f706	84	case rcode_servfail:
98a3f706	85	adns__query_fail(ads,qu,adns_s_servfail);
ec477b9e	86	return;
b9de380c	87	case rcode_notimp:
31144a72	88	adns__warn(ads,serv,qu,"server claims not to implement our query");
b9de380c	89	adns__query_fail(ads,qu,adns_s_notimplemented);
	90	return;
	91	case rcode_refused:
31144a72	92	adns__warn(ads,serv,qu,"server refused our query");
b9de380c	93	adns__query_fail(ads,qu,adns_s_refused);
	94	return;
	95	default:
31144a72	96	adns__warn(ads,serv,qu,"server gave unknown response code %d",rcode);
b9de380c	97	adns__query_fail(ads,qu,adns_s_reasonunknown);
	98	return;
	99	}
	100
	101	/* Now, take a look at the answer section, and see if it is complete.
	102	* If it has any CNAMEs we stuff them in the answer.
	103	*/
	104	wantedrrs= 0;
	105	for (rri= 0; rri<ancount; rri++) {
	106	rrstart= cbyte;
31144a72	107	if (qu->cname_dgram >= 0) {
f1e474dd	108	st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
f1e474dd	109	&rrtype,&rrclass,&rdlength,&rdstart,
31144a72	110	qu->cname_dgram,qu->cname_dglen,qu->cname_begin, &ownermatched);
0ba0614a	111	} else {
31144a72	112	st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
	113	&rrtype,&rrclass,&rdlength,&rdstart,
	114	qu->querymsg,qu->querylen,DNS_HDRSIZE, &ownermatched);
0ba0614a	115	}
b9de380c	116	if (st) adns__query_fail(ads,qu,st);
0ba0614a	117	if (rrtype == -1) goto x_truncated;
0ba0614a	118
b9de380c	119	if (rrclass != DNS_CLASS_IN) {
31144a72	120	adns__diag(ads,serv,qu,"ignoring answer RR with wrong class %d (expected IN=%d)",
b9de380c	121	rrclass,DNS_CLASS_IN);
	122	continue;
	123	}
0ba0614a	124	if (!ownermatched) {
98a3f706	125	if (ads->iflags & adns_if_debug) {
31144a72	126	adns__debug(ads,serv,qu,"ignoring RR with an unexpected owner %s",
	127	adns__diag_domain(ads,serv,&vb,qu->flags,
	128	dgram,dglen,rrstart,dglen));
0ba0614a	129	}
b9de380c	130	continue;
b9de380c	131	}
31144a72	132	if (rrtype == adns_r_cname &&
	133	(qu->typei->type & adns__rrt_typemask) != adns_r_cname) {
	134	if (!qu->cname_str) { /* Ignore second and subsequent CNAMEs */
	135	qu->cname_begin= rdstart;
	136	qu->cname_dgram= dgram;
	137	qu->cname_dglen= dglen;
	138	st= adns__parse_domain(ads,serv,&vb,qu->flags,
	139	dgram,dglen, &rdstart,rdstart+rdlength);
	140	if (!vb.used) goto x_truncated;
	141	if (st) { adns__query_fail(ads,qu,st); return; }
	142	qu->cname_str= adns__vbuf_extractstring(&vb);
	143	/* If we find the answer section truncated after this point we restart
	144	* the query at the CNAME; if beforehand then we obviously have to use
	145	* TCP. If there is no truncation we can use the whole answer if
	146	* it contains the relevant info.
	147	*/
	148	} else {
	149	adns__debug(ads,serv,qu,"ignoring duplicate CNAME (%s, as well as %s)",
	150	adns__diag_domain(ads,serv,&vb,qu->flags,
	151	dgram,dglen, rdstart,rdstart+rdlength),
	152	qu->cname_str);
	153	}
98a3f706	154	} else if (rrtype == (qu->typei->type & adns__rrt_typemask)) {
b9de380c	155	wantedrrs++;
b9de380c	156	} else {
31144a72	157	adns__debug(ads,serv,qu,"ignoring answer RR with irrelevant type %d",rrtype);
b9de380c	158	}
	159	}
	160
	161	/* If we got here then the answer section is intact. */
	162	nsstart= cbyte;
	163
	164	if (!wantedrrs) {
	165	/* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */
	166
	167	if (rcode == rcode_nxdomain) {
0ba0614a	168	adns__query_finish(ads,qu,adns_s_nxdomain);
b9de380c	169	return;
	170	}
	171
	172	/* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */
0ba0614a	173	foundsoa= 0; foundns= 0;
b9de380c	174	for (rri= 0; rri<nscount; rri++) {
0ba0614a	175	rrstart= cbyte;
31144a72	176	st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
	177	&rrtype,&rrclass,&rdlength,&rdstart,
	178	0,0,0,0);
98a3f706	179	if (st) { adns__query_fail(ads,qu,st); return; }
0ba0614a	180	if (rrtype==-1) goto x_truncated;
0ba0614a	181	if (rrclass != DNS_CLASS_IN) {
31144a72	182	adns__diag(ads,serv,qu,
31144a72	183	"ignoring authority RR with wrong class %d (expected IN=%d)",
0ba0614a	184	rrclass,DNS_CLASS_IN);
	185	continue;
	186	}
	187	if (rrtype == adns_r_soa_raw) { foundsoa= 1; break; }
	188	else if (rrtype == adns_r_ns_raw) { foundns= 1; }
b9de380c	189	}
0ba0614a	190
	191	if (foundsoa \|\| !foundns) {
	192	/* Aha ! A NODATA response, good. */
	193	adns__query_finish(ads,qu,adns_s_nodata);
	194	return;
	195	}
	196
	197	/* Now what ? No relevant answers, no SOA, and at least some NS's.
	198	* Looks like a referral. Just one last chance ... if we came across
31144a72	199	* a CNAME in this datagram then we should probably do our own CNAME
31144a72	200	* lookup now in the hope that we won't get a referral again.
0ba0614a	201	*/
31144a72	202	if (qu->cname_dgram == dgram) { cname_recurse(ads,qu,0); return; }
0ba0614a	203
0ba0614a	204	/* Bloody hell, I thought we asked for recursion ? */
31144a72	205	if (flg_rd) {
	206	adns__diag(ads,serv,qu,"server thinks we didn't ask for recursive lookup");
	207	}
0ba0614a	208	if (!flg_ra) {
31144a72	209	adns__diag(ads,serv,qu,"server is not willing to do recursive lookups for us");
0ba0614a	210	adns__query_fail(ads,qu,adns_s_norecurse);
31144a72	211	} else {
	212	adns__diag(ads,serv,qu,"server claims to do recursion, but gave us a referral");
	213	adns__query_fail(ads,qu,adns_s_serverfaulty);
0ba0614a	214	}
b9de380c	215	return;
	216	}
	217
0ba0614a	218	/* Now, we have some RRs which we wanted. */
b9de380c	219
31144a72	220	if (!adns__vbuf_ensure(&qu->ansbuf,qu->typei->rrsz*wantedrrs)) {
	221	adns__query_fail(ads,qu,adns_s_nolocalmem);
	222	return;
	223	}
98a3f706	224
	225	cbyte= anstart;
	226	currentrrs= 0;
	227	arstart= -1;
31144a72	228	qu->ansbuf.used= 0;
98a3f706	229	for (rri=0; rri<ancount; rri++) {
31144a72	230	if (qu->cname_dgram >= 0) {
	231	st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
	232	&rrtype,&rrclass,&rdlength,&rdstart,
	233	qu->cname_dgram,qu->cname_dglen,qu->cname_begin, &ownermatched);
	234	} else {
	235	st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
	236	&rrtype,&rrclass,&rdlength,&rdstart,
	237	qu->querymsg,qu->querylen,DNS_HDRSIZE, &ownermatched);
	238	}
98a3f706	239	assert(!st); assert(rrtype != -1);
98a3f706	240	if (rrclass != DNS_CLASS_IN \|\|
31144a72	241	rrtype != (qu->typei->type & adns__rrt_typemask) \|\|
31144a72	242	!ownermatched)
98a3f706	243	continue;
98a3f706	244	assert(currentrrs<wantedrrs);
31144a72	245	qu->ansbuf.used += quj->typei->rrsz;
	246	st= qu->typei->parse(ads,qu,serv,&vb,
	247	dgram,dglen, &rdstart,rdstart+rdlength,
	248	(void*)(qu->ansbuf.buf+qu->ansbuf.used));
98a3f706	249	if (st) { adns__query_fail(ads,qu,st); return; }
31144a72	250	if (rdstart==-1) goto x_truncated;
98a3f706	251	}
b9de380c	252
98a3f706	253	/* This may have generated some child queries ... */
	254	if (qu->children.head) {
	255	qu->state= query_child;
	256	LIST_LINK_TAIL(ads->childw,qu);
	257	return;
b9de380c	258	}
ec477b9e	259
98a3f706	260	adns__query_finish(ads,qu,adns_s_ok);
98a3f706	261	return;
0ba0614a	262
98a3f706	263	x_truncated:
98a3f706	264	if (!flg_tc) {
31144a72	265	adns__diag(ads,serv,qu,"server sent datagram which points outside itself");
98a3f706	266	adns__query_fail(ads,qu,adns_s_serverfaulty);
	267	return;
	268	}
31144a72	269	if (qu->cname_dgram) { cname_recurse(ads,qu,adns_qf_usevc); return; }
98a3f706	270	ans= (adns_answer*)qu->ans.buf;
	271	ans->nrrs= 0;
	272	qu->ans.used= sizeof(adns_answer);
	273	qu->flags \|= adns_qf_usevc;
	274	adns__query_udp(ads,qu,now);
	275	}