[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;
  
  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,&qu->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,&qu->vb,qu->flags,
			       dgram,dglen, &rdstart,rdstart+rdlength);
	if (!vb.used) goto x_truncated;
	if (st) { adns__query_fail(ads,qu,st); return; }
	qu->answer->cname= adns__savestring(qu);
	if (!qu->answer->cname) return;
	/* 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,&qu->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. */

  qu->ans->rrs= adns__alloc_interim(qu,qu->typei->rrsz*wantedrrs);
  if (!qu->ans->rrs) return;

  cbyte= anstart;
  arstart= -1;
  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(qu->ans->nrrs<wantedrrs);
    st= qu->typei->parse(ads,qu,serv,
			 dgram,dglen, &rdstart,rdstart+rdlength,
			 qu->ans->rrs.bytes+qu->ans->nrrs*quj->typei->rrsz);
    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; }
  adns__reset_cnameonly(ads,qu);
  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;
ec477b9e	19
98a3f706	20	if (dglen<DNS_HDRSIZE) {
98a3f706	21	adns__diag(ads,serv,"received datagram too short for message header (%d)",dglen);
ec477b9e	22	return;
ec477b9e	23	}
b9de380c	24	GET_W(cbyte,id);
	25	GET_B(cbyte,f1);
	26	GET_B(cbyte,f2);
	27	GET_W(cbyte,qdcount);
	28	GET_W(cbyte,ancount);
	29	GET_W(cbyte,nscount);
	30	GET_W(cbyte,arcount);
98a3f706	31	assert(cbyte == DNS_HDRSIZE);
ec477b9e	32
31144a72	33	flg_qr= f1&0x80;
31144a72	34	opcode= (f1&0x78)>>3;
98a3f706	35	flg_tc= f1&0x20;
31144a72	36	flg_rd= f1&0x01;
0ba0614a	37	flg_ra= f2&0x80;
31144a72	38	rcode= (f1&0x0f);
0ba0614a	39
31144a72	40	if (flg_qr) {
ec477b9e	41	adns__diag(ads,serv,"server sent us a query, not a response");
	42	return;
	43	}
31144a72	44	if (opcode) {
31144a72	45	adns__diag(ads,serv,"server sent us unknown opcode %d (wanted 0=QUERY)",opcode);
ec477b9e	46	return;
	47	}
	48	if (!qdcount) {
	49	adns__diag(ads,serv,"server sent reply without quoting our question");
	50	return;
	51	} else if (qdcount>1) {
	52	adns__diag(ads,serv,"server claimed to answer %d questions with one message",
	53	qdcount);
	54	return;
	55	}
98a3f706	56	for (qu= ads->timew.head; qu; qu= nqu) {
ec477b9e	57	nqu= qu->next;
ec477b9e	58	if (qu->id != id) continue;
98a3f706	59	if (dglen < qu->querylen) continue;
98a3f706	60	if (memcmp(qu->querymsg+DNS_HDRSIZE,dgram+DNS_HDRSIZE,qu->querylen-DNS_HDRSIZE))
b9de380c	61	continue;
ec477b9e	62	break;
ec477b9e	63	}
98a3f706	64	assert(qu->cnameoff == -1);
b9de380c	65	anstart= qu->querylen;
ec477b9e	66	if (!qu) {
	67	adns__debug(ads,serv,"reply not found (id=%02x)",id);
	68	return;
	69	}
98a3f706	70
	71	LIST_UNLINK(ads->timew,qu);
	72	/* We're definitely going to do something with this query now */
	73
b9de380c	74	switch (rcode) {
	75	case rcode_noerror:
	76	case rcode_nxdomain:
ec477b9e	77	break;
b9de380c	78	case rcode_formaterror:
31144a72	79	adns__warn(ads,serv,qu,"server cannot understand our query (Format Error)");
ec477b9e	80	adns__query_fail(ads,qu,adns_s_serverfaulty);
ec477b9e	81	return;
98a3f706	82	case rcode_servfail:
98a3f706	83	adns__query_fail(ads,qu,adns_s_servfail);
ec477b9e	84	return;
b9de380c	85	case rcode_notimp:
31144a72	86	adns__warn(ads,serv,qu,"server claims not to implement our query");
b9de380c	87	adns__query_fail(ads,qu,adns_s_notimplemented);
	88	return;
	89	case rcode_refused:
31144a72	90	adns__warn(ads,serv,qu,"server refused our query");
b9de380c	91	adns__query_fail(ads,qu,adns_s_refused);
	92	return;
	93	default:
31144a72	94	adns__warn(ads,serv,qu,"server gave unknown response code %d",rcode);
b9de380c	95	adns__query_fail(ads,qu,adns_s_reasonunknown);
	96	return;
	97	}
	98
	99	/* Now, take a look at the answer section, and see if it is complete.
	100	* If it has any CNAMEs we stuff them in the answer.
	101	*/
	102	wantedrrs= 0;
	103	for (rri= 0; rri<ancount; rri++) {
	104	rrstart= cbyte;
31144a72	105	if (qu->cname_dgram >= 0) {
f1e474dd	106	st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
f1e474dd	107	&rrtype,&rrclass,&rdlength,&rdstart,
31144a72	108	qu->cname_dgram,qu->cname_dglen,qu->cname_begin, &ownermatched);
0ba0614a	109	} else {
31144a72	110	st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
	111	&rrtype,&rrclass,&rdlength,&rdstart,
	112	qu->querymsg,qu->querylen,DNS_HDRSIZE, &ownermatched);
0ba0614a	113	}
b9de380c	114	if (st) adns__query_fail(ads,qu,st);
0ba0614a	115	if (rrtype == -1) goto x_truncated;
0ba0614a	116
b9de380c	117	if (rrclass != DNS_CLASS_IN) {
31144a72	118	adns__diag(ads,serv,qu,"ignoring answer RR with wrong class %d (expected IN=%d)",
b9de380c	119	rrclass,DNS_CLASS_IN);
	120	continue;
	121	}
0ba0614a	122	if (!ownermatched) {
98a3f706	123	if (ads->iflags & adns_if_debug) {
31144a72	124	adns__debug(ads,serv,qu,"ignoring RR with an unexpected owner %s",
8e5b0abb	125	adns__diag_domain(ads,serv,&qu->vb,qu->flags,
31144a72	126	dgram,dglen,rrstart,dglen));
0ba0614a	127	}
b9de380c	128	continue;
b9de380c	129	}
31144a72	130	if (rrtype == adns_r_cname &&
	131	(qu->typei->type & adns__rrt_typemask) != adns_r_cname) {
	132	if (!qu->cname_str) { /* Ignore second and subsequent CNAMEs */
	133	qu->cname_begin= rdstart;
	134	qu->cname_dgram= dgram;
	135	qu->cname_dglen= dglen;
8e5b0abb	136	st= adns__parse_domain(ads,serv,&qu->vb,qu->flags,
31144a72	137	dgram,dglen, &rdstart,rdstart+rdlength);
	138	if (!vb.used) goto x_truncated;
	139	if (st) { adns__query_fail(ads,qu,st); return; }
8e5b0abb	140	qu->answer->cname= adns__savestring(qu);
8e5b0abb	141	if (!qu->answer->cname) return;
31144a72	142	/* If we find the answer section truncated after this point we restart
	143	* the query at the CNAME; if beforehand then we obviously have to use
	144	* TCP. If there is no truncation we can use the whole answer if
	145	* it contains the relevant info.
	146	*/
	147	} else {
	148	adns__debug(ads,serv,qu,"ignoring duplicate CNAME (%s, as well as %s)",
8e5b0abb	149	adns__diag_domain(ads,serv,&qu->vb,qu->flags,
31144a72	150	dgram,dglen, rdstart,rdstart+rdlength),
	151	qu->cname_str);
	152	}
98a3f706	153	} else if (rrtype == (qu->typei->type & adns__rrt_typemask)) {
b9de380c	154	wantedrrs++;
b9de380c	155	} else {
31144a72	156	adns__debug(ads,serv,qu,"ignoring answer RR with irrelevant type %d",rrtype);
b9de380c	157	}
	158	}
	159
	160	/* If we got here then the answer section is intact. */
	161	nsstart= cbyte;
	162
	163	if (!wantedrrs) {
	164	/* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */
	165
	166	if (rcode == rcode_nxdomain) {
0ba0614a	167	adns__query_finish(ads,qu,adns_s_nxdomain);
b9de380c	168	return;
	169	}
	170
	171	/* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */
0ba0614a	172	foundsoa= 0; foundns= 0;
b9de380c	173	for (rri= 0; rri<nscount; rri++) {
0ba0614a	174	rrstart= cbyte;
31144a72	175	st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
	176	&rrtype,&rrclass,&rdlength,&rdstart,
	177	0,0,0,0);
98a3f706	178	if (st) { adns__query_fail(ads,qu,st); return; }
0ba0614a	179	if (rrtype==-1) goto x_truncated;
0ba0614a	180	if (rrclass != DNS_CLASS_IN) {
31144a72	181	adns__diag(ads,serv,qu,
31144a72	182	"ignoring authority RR with wrong class %d (expected IN=%d)",
0ba0614a	183	rrclass,DNS_CLASS_IN);
	184	continue;
	185	}
	186	if (rrtype == adns_r_soa_raw) { foundsoa= 1; break; }
	187	else if (rrtype == adns_r_ns_raw) { foundns= 1; }
b9de380c	188	}
0ba0614a	189
	190	if (foundsoa \|\| !foundns) {
	191	/* Aha ! A NODATA response, good. */
	192	adns__query_finish(ads,qu,adns_s_nodata);
	193	return;
	194	}
	195
	196	/* Now what ? No relevant answers, no SOA, and at least some NS's.
	197	* Looks like a referral. Just one last chance ... if we came across
31144a72	198	* a CNAME in this datagram then we should probably do our own CNAME
31144a72	199	* lookup now in the hope that we won't get a referral again.
0ba0614a	200	*/
31144a72	201	if (qu->cname_dgram == dgram) { cname_recurse(ads,qu,0); return; }
0ba0614a	202
0ba0614a	203	/* Bloody hell, I thought we asked for recursion ? */
31144a72	204	if (flg_rd) {
	205	adns__diag(ads,serv,qu,"server thinks we didn't ask for recursive lookup");
	206	}
0ba0614a	207	if (!flg_ra) {
31144a72	208	adns__diag(ads,serv,qu,"server is not willing to do recursive lookups for us");
0ba0614a	209	adns__query_fail(ads,qu,adns_s_norecurse);
31144a72	210	} else {
	211	adns__diag(ads,serv,qu,"server claims to do recursion, but gave us a referral");
	212	adns__query_fail(ads,qu,adns_s_serverfaulty);
0ba0614a	213	}
b9de380c	214	return;
	215	}
	216
0ba0614a	217	/* Now, we have some RRs which we wanted. */
b9de380c	218
8e5b0abb	219	qu->ans->rrs= adns__alloc_interim(qu,qu->typei->rrsz*wantedrrs);
8e5b0abb	220	if (!qu->ans->rrs) return;
98a3f706	221
98a3f706	222	cbyte= anstart;
98a3f706	223	arstart= -1;
98a3f706	224	for (rri=0; rri<ancount; rri++) {
31144a72	225	if (qu->cname_dgram >= 0) {
	226	st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
	227	&rrtype,&rrclass,&rdlength,&rdstart,
	228	qu->cname_dgram,qu->cname_dglen,qu->cname_begin, &ownermatched);
	229	} else {
	230	st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
	231	&rrtype,&rrclass,&rdlength,&rdstart,
	232	qu->querymsg,qu->querylen,DNS_HDRSIZE, &ownermatched);
	233	}
98a3f706	234	assert(!st); assert(rrtype != -1);
98a3f706	235	if (rrclass != DNS_CLASS_IN \|\|
31144a72	236	rrtype != (qu->typei->type & adns__rrt_typemask) \|\|
31144a72	237	!ownermatched)
98a3f706	238	continue;
8e5b0abb	239	assert(qu->ans->nrrs<wantedrrs);
8e5b0abb	240	st= qu->typei->parse(ads,qu,serv,
31144a72	241	dgram,dglen, &rdstart,rdstart+rdlength,
8e5b0abb	242	qu->ans->rrs.bytes+qu->ans->nrrs*quj->typei->rrsz);
98a3f706	243	if (st) { adns__query_fail(ads,qu,st); return; }
31144a72	244	if (rdstart==-1) goto x_truncated;
98a3f706	245	}
b9de380c	246
98a3f706	247	/* This may have generated some child queries ... */
	248	if (qu->children.head) {
	249	qu->state= query_child;
	250	LIST_LINK_TAIL(ads->childw,qu);
	251	return;
b9de380c	252	}
ec477b9e	253
98a3f706	254	adns__query_finish(ads,qu,adns_s_ok);
98a3f706	255	return;
0ba0614a	256
98a3f706	257	x_truncated:
98a3f706	258	if (!flg_tc) {
31144a72	259	adns__diag(ads,serv,qu,"server sent datagram which points outside itself");
98a3f706	260	adns__query_fail(ads,qu,adns_s_serverfaulty);
	261	return;
	262	}
31144a72	263	if (qu->cname_dgram) { cname_recurse(ads,qu,adns_qf_usevc); return; }
8e5b0abb	264	adns__reset_cnameonly(ads,qu);
98a3f706	265	qu->flags \|= adns_qf_usevc;
	266	adns__query_udp(ads,qu,now);
	267	}