[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_tc;
  int rrtype, rrclass, rdlength, rdstart, ownermatched, ownerstart;
  int anstart, nsstart, arstart;
  int currentrrs;
  adns_query qu, nqu;
  dns_rcode rcode;
  adns_status st;
= 0;
  
  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_tc= f1&0x20;
  flg_ra= f2&0x80;

  if (f1&0x80) {
    adns__diag(ads,serv,"server sent us a query, not a response");
    return;
  }
  if (f1&0x70) {
    adns__diag(ads,serv,"server sent us unknown opcode %d (wanted 0=QUERY)",
	       (f1>>4)&0x70);
    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 */
  
  if (!(f1&0x01)) {
    adns__diag(ads,serv,"server thinks we didn't ask for recursive lookup");
    adns__query_fail(ads,qu,adns_s_serverfaulty);
    return;
  }

  rcode= (f1&0x0f);
  switch (rcode) {
  case rcode_noerror:
  case rcode_nxdomain:
    break;
  case rcode_formaterror:
    adns__warn(ads,serv,"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,"server claims not to implement our query");
    adns__query_fail(ads,qu,adns_s_notimplemented);
    return;
  case rcode_refused:
    adns__warn(ads,serv,"server refused our query");
    adns__query_fail(ads,qu,adns_s_refused);
    return;
  default:
    adns__warn(ads,serv,"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->cnameoff >= 0) {
      st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
		       &rrtype,&rrclass,&rdlength,&rdstart,
		       dgram,dglen,qu->cnameoff, &ownermatched);
    } else {
      st= adns__get_rr_temp(ads,qu,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,"ignoring answer RR with wrong class %d (expected IN=%d)",
		 rrclass,DNS_CLASS_IN);
      continue;
    }
    if (!ownermatched) {
      if (ads->iflags & adns_if_debug) {
	st= adns__get_domain_temp(ads,qu,serv, dgram,dglen,&rrstart,dglen, &ownerstart);
	if (st)
	  adns__debug(ads,serv, "ignoring RR with an irrelevant owner"
		      " whose format is bad, code %d",st);
	else if (ownerstart>=0)
	  adns__debug(ads,serv, "ignoring RR with an irrelevant owner"
		      " \"%s\"", qu->ans.buf+ownerstart);
	else
	  adns__debug(ads,serv,"ignoring RR with an irrelevant truncated owner");
      }
      continue;
    }
    if (qu->cnameoff<0 &&
	(qu->typei->type & adns__rrt_typemask) != adns_r_cname &&
	rrtype == adns_r_cname) { /* Ignore second and subsequent CNAMEs */
      st= adns__get_domain_perm(ads,qu,serv, dgram,dglen,
				&rdstart,rdstart+rdlength,&qu->cnameoff);
      if (st) { adns__query_fail(ads,qu,st); return; }
      if (qu->cnameoff==-1) goto x_truncated;
      /* 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 if (rrtype == (qu->typei->type & adns__rrt_typemask)) {
      wantedrrs++;
    } else {
      adns__debug(ads,serv,"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__get_rr_temp(ads,qu,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,"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 then perhaps we should do our own CNAME lookup.
     */
    if (qu->cnameoff != -1) { cname_recurse(ads,qu,0); return; }

    /* Bloody hell, I thought we asked for recursion ? */
    if (!flg_ra) {
      adns__diag(ads,serv,"server is not willing to do recursive lookups for us");
      adns__query_fail(ads,qu,adns_s_norecurse);
      return;
    }
    adns__diag(ads,serv,"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->rrsoff= adns__vbuf_malloc(&qu->ans,qu->typei->rrsz*wantedrrs);
  if (qu->rrsoff == -1) adns__query_fail(ads,qu,adns_s_nolocalmem);

  cbyte= anstart;
  currentrrs= 0;
  arstart= -1;
  for (rri=0; rri<ancount; rri++) {
    st= adns__get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte,
			  &rrtype,&rrclass, &rdlength,&rdstart, 0,0,0,0);
    assert(!st); assert(rrtype != -1);
    if (rrclass != DNS_CLASS_IN ||
	rrtype != (qu->typei->type & adns__rrt_typemask))
      continue;
    assert(currentrrs<wantedrrs);
    st= qu->typei->get_fn(ads,qu,serv, dgram,dglen, &rdstart,rdstart+rdlength,
			  nsstart,arcount,&arstart, qu->rrsoff,&currentrrs);
    if (st) { adns__query_fail(ads,qu,st); return; }
    if (currentrrs==-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,"server sent datagram which points outside itself");
    adns__query_fail(ads,qu,adns_s_serverfaulty);
    return;
  }
  if (qu->cnameoff != -1) { cname_recurse(ads,qu,adns_qf_usevc); return; }
  qu->cnameoff= -1;
  qu->rrsoff= -1;
  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;
	12	int id, f1, f2, qdcount, ancount, nscount, arcount, flg_ra, flg_tc;
	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;
f1e474dd	19	= 0;
ec477b9e	20
98a3f706	21	if (dglen<DNS_HDRSIZE) {
98a3f706	22	adns__diag(ads,serv,"received datagram too short for message header (%d)",dglen);
ec477b9e	23	return;
ec477b9e	24	}
b9de380c	25	GET_W(cbyte,id);
	26	GET_B(cbyte,f1);
	27	GET_B(cbyte,f2);
	28	GET_W(cbyte,qdcount);
	29	GET_W(cbyte,ancount);
	30	GET_W(cbyte,nscount);
	31	GET_W(cbyte,arcount);
98a3f706	32	assert(cbyte == DNS_HDRSIZE);
ec477b9e	33
98a3f706	34	flg_tc= f1&0x20;
0ba0614a	35	flg_ra= f2&0x80;
0ba0614a	36
ec477b9e	37	if (f1&0x80) {
	38	adns__diag(ads,serv,"server sent us a query, not a response");
	39	return;
	40	}
	41	if (f1&0x70) {
	42	adns__diag(ads,serv,"server sent us unknown opcode %d (wanted 0=QUERY)",
	43	(f1>>4)&0x70);
	44	return;
	45	}
	46	if (!qdcount) {
	47	adns__diag(ads,serv,"server sent reply without quoting our question");
	48	return;
	49	} else if (qdcount>1) {
	50	adns__diag(ads,serv,"server claimed to answer %d questions with one message",
	51	qdcount);
	52	return;
	53	}
98a3f706	54	for (qu= ads->timew.head; qu; qu= nqu) {
ec477b9e	55	nqu= qu->next;
ec477b9e	56	if (qu->id != id) continue;
98a3f706	57	if (dglen < qu->querylen) continue;
98a3f706	58	if (memcmp(qu->querymsg+DNS_HDRSIZE,dgram+DNS_HDRSIZE,qu->querylen-DNS_HDRSIZE))
b9de380c	59	continue;
ec477b9e	60	break;
ec477b9e	61	}
98a3f706	62	assert(qu->cnameoff == -1);
b9de380c	63	anstart= qu->querylen;
ec477b9e	64	if (!qu) {
	65	adns__debug(ads,serv,"reply not found (id=%02x)",id);
	66	return;
	67	}
98a3f706	68
	69	LIST_UNLINK(ads->timew,qu);
	70	/* We're definitely going to do something with this query now */
	71
ec477b9e	72	if (!(f1&0x01)) {
	73	adns__diag(ads,serv,"server thinks we didn't ask for recursive lookup");
	74	adns__query_fail(ads,qu,adns_s_serverfaulty);
	75	return;
	76	}
b9de380c	77
	78	rcode= (f1&0x0f);
	79	switch (rcode) {
	80	case rcode_noerror:
	81	case rcode_nxdomain:
ec477b9e	82	break;
b9de380c	83	case rcode_formaterror:
b9de380c	84	adns__warn(ads,serv,"server cannot understand our query (Format Error)");
ec477b9e	85	adns__query_fail(ads,qu,adns_s_serverfaulty);
ec477b9e	86	return;
98a3f706	87	case rcode_servfail:
98a3f706	88	adns__query_fail(ads,qu,adns_s_servfail);
ec477b9e	89	return;
b9de380c	90	case rcode_notimp:
	91	adns__warn(ads,serv,"server claims not to implement our query");
	92	adns__query_fail(ads,qu,adns_s_notimplemented);
	93	return;
	94	case rcode_refused:
	95	adns__warn(ads,serv,"server refused our query");
	96	adns__query_fail(ads,qu,adns_s_refused);
	97	return;
	98	default:
	99	adns__warn(ads,serv,"server gave unknown response code %d",rcode);
	100	adns__query_fail(ads,qu,adns_s_reasonunknown);
	101	return;
	102	}
	103
	104	/* Now, take a look at the answer section, and see if it is complete.
	105	* If it has any CNAMEs we stuff them in the answer.
	106	*/
	107	wantedrrs= 0;
	108	for (rri= 0; rri<ancount; rri++) {
	109	rrstart= cbyte;
98a3f706	110	if (qu->cnameoff >= 0) {
f1e474dd	111	st= adns__findrr(ads,serv, dgram,dglen,&cbyte,
	112	&rrtype,&rrclass,&rdlength,&rdstart,
	113	dgram,dglen,qu->cnameoff, &ownermatched);
0ba0614a	114	} else {
98a3f706	115	st= adns__get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte,
	116	&rrtype,&rrclass,&rdlength,&rdstart,
	117	qu->querymsg,qu->querylen,DNS_HDRSIZE, &ownermatched);
0ba0614a	118	}
b9de380c	119	if (st) adns__query_fail(ads,qu,st);
0ba0614a	120	if (rrtype == -1) goto x_truncated;
0ba0614a	121
b9de380c	122	if (rrclass != DNS_CLASS_IN) {
0ba0614a	123	adns__diag(ads,serv,"ignoring answer RR with wrong class %d (expected IN=%d)",
b9de380c	124	rrclass,DNS_CLASS_IN);
	125	continue;
	126	}
0ba0614a	127	if (!ownermatched) {
98a3f706	128	if (ads->iflags & adns_if_debug) {
	129	st= adns__get_domain_temp(ads,qu,serv, dgram,dglen,&rrstart,dglen, &ownerstart);
	130	if (st)
	131	adns__debug(ads,serv, "ignoring RR with an irrelevant owner"
	132	" whose format is bad, code %d",st);
	133	else if (ownerstart>=0)
	134	adns__debug(ads,serv, "ignoring RR with an irrelevant owner"
	135	" \"%s\"", qu->ans.buf+ownerstart);
	136	else
	137	adns__debug(ads,serv,"ignoring RR with an irrelevant truncated owner");
0ba0614a	138	}
b9de380c	139	continue;
b9de380c	140	}
98a3f706	141	if (qu->cnameoff<0 &&
	142	(qu->typei->type & adns__rrt_typemask) != adns_r_cname &&
	143	rrtype == adns_r_cname) { /* Ignore second and subsequent CNAMEs */
	144	st= adns__get_domain_perm(ads,qu,serv, dgram,dglen,
	145	&rdstart,rdstart+rdlength,&qu->cnameoff);
	146	if (st) { adns__query_fail(ads,qu,st); return; }
	147	if (qu->cnameoff==-1) goto x_truncated;
0ba0614a	148	/* If we find the answer section truncated after this point we restart
	149	* the query at the CNAME; if beforehand then we obviously have to use
	150	* TCP. If there is no truncation we can use the whole answer if
	151	* it contains the relevant info.
	152	*/
98a3f706	153	} else if (rrtype == (qu->typei->type & adns__rrt_typemask)) {
b9de380c	154	wantedrrs++;
	155	} else {
	156	adns__debug(ads,serv,"ignoring answer RR with irrelevant type %d",rrtype);
	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;
98a3f706	175	st= adns__get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte,
	176	&rrtype,&rrclass, &rdlength,&rdstart, 0,0,0,0);
	177	if (st) { adns__query_fail(ads,qu,st); return; }
0ba0614a	178	if (rrtype==-1) goto x_truncated;
	179	if (rrclass != DNS_CLASS_IN) {
	180	adns__diag(ads,serv,"ignoring authority RR with wrong class %d (expected IN=%d)",
	181	rrclass,DNS_CLASS_IN);
	182	continue;
	183	}
	184	if (rrtype == adns_r_soa_raw) { foundsoa= 1; break; }
	185	else if (rrtype == adns_r_ns_raw) { foundns= 1; }
b9de380c	186	}
0ba0614a	187
	188	if (foundsoa \|\| !foundns) {
	189	/* Aha ! A NODATA response, good. */
	190	adns__query_finish(ads,qu,adns_s_nodata);
	191	return;
	192	}
	193
	194	/* Now what ? No relevant answers, no SOA, and at least some NS's.
	195	* Looks like a referral. Just one last chance ... if we came across
	196	* a CNAME then perhaps we should do our own CNAME lookup.
	197	*/
98a3f706	198	if (qu->cnameoff != -1) { cname_recurse(ads,qu,0); return; }
0ba0614a	199
	200	/* Bloody hell, I thought we asked for recursion ? */
	201	if (!flg_ra) {
	202	adns__diag(ads,serv,"server is not willing to do recursive lookups for us");
	203	adns__query_fail(ads,qu,adns_s_norecurse);
	204	return;
	205	}
	206	adns__diag(ads,serv,"server claims to do recursion, but gave us a referral");
98a3f706	207	adns__query_fail(ads,qu,adns_s_serverfaulty);
b9de380c	208	return;
	209	}
	210
0ba0614a	211	/* Now, we have some RRs which we wanted. */
b9de380c	212
98a3f706	213	qu->rrsoff= adns__vbuf_malloc(&qu->ans,qu->typei->rrsz*wantedrrs);
	214	if (qu->rrsoff == -1) adns__query_fail(ads,qu,adns_s_nolocalmem);
	215
	216	cbyte= anstart;
	217	currentrrs= 0;
	218	arstart= -1;
	219	for (rri=0; rri<ancount; rri++) {
	220	st= adns__get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte,
	221	&rrtype,&rrclass, &rdlength,&rdstart, 0,0,0,0);
	222	assert(!st); assert(rrtype != -1);
	223	if (rrclass != DNS_CLASS_IN \|\|
	224	rrtype != (qu->typei->type & adns__rrt_typemask))
	225	continue;
	226	assert(currentrrs<wantedrrs);
	227	st= qu->typei->get_fn(ads,qu,serv, dgram,dglen, &rdstart,rdstart+rdlength,
	228	nsstart,arcount,&arstart, qu->rrsoff,&currentrrs);
	229	if (st) { adns__query_fail(ads,qu,st); return; }
	230	if (currentrrs==-1) goto x_truncated;
	231	}
b9de380c	232
98a3f706	233	/* This may have generated some child queries ... */
	234	if (qu->children.head) {
	235	qu->state= query_child;
	236	LIST_LINK_TAIL(ads->childw,qu);
	237	return;
b9de380c	238	}
ec477b9e	239
98a3f706	240	adns__query_finish(ads,qu,adns_s_ok);
98a3f706	241	return;
0ba0614a	242
98a3f706	243	x_truncated:
	244	if (!flg_tc) {
	245	adns__diag(ads,serv,"server sent datagram which points outside itself");
	246	adns__query_fail(ads,qu,adns_s_serverfaulty);
	247	return;
	248	}
	249	if (qu->cnameoff != -1) { cname_recurse(ads,qu,adns_qf_usevc); return; }
	250	qu->cnameoff= -1;
	251	qu->rrsoff= -1;
	252	ans= (adns_answer*)qu->ans.buf;
	253	ans->nrrs= 0;
	254	qu->ans.used= sizeof(adns_answer);
	255	qu->flags \|= adns_qf_usevc;
	256	adns__query_udp(ads,qu,now);
	257	}