X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git;a=blobdiff_plain;f=src%2Freply.c;h=586aff0ca6045dd12a5b9fb94369d792dfdef522;hp=14fc05786a0d794fe3e730c0b8645e108eb6dc08;hb=5b9dd636d9afe29576a0da94a5cdfe227f3a6853;hpb=f1e474dda132e6d9626bc9930fd9025616de81fb diff --git a/src/reply.c b/src/reply.c index 14fc057..586aff0 100644 --- a/src/reply.c +++ b/src/reply.c @@ -1,27 +1,56 @@ -/**/ +/* + * reply.c + * - main handling and parsing routine for received datagrams + */ +/* + * This file is + * Copyright (C) 1997-1999 Ian Jackson + * + * It is part of adns, which is + * Copyright (C) 1997-1999 Ian Jackson + * Copyright (C) 1999 Tony Finch + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ -#include "internal.h" +#include -static void cname_recurse(adns_state ads, adns_query qu, adns_queryflags xflags) { - abort(); /* FIXME */ -} +#include "internal.h" 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 serv, int viatcp, struct timeval now) { + int cbyte, rrstart, wantedrrs, rri, foundsoa, foundns, cname_here; + int id, f1, f2, qdcount, ancount, nscount, arcount; + int flg_ra, flg_rd, flg_tc, flg_qr, opcode; + int rrtype, rrclass, rdlength, rdstart; int anstart, nsstart, arstart; - int currentrrs; + int ownermatched, l, nrrs; + unsigned long ttl, soattl; + const typeinfo *typei; adns_query qu, nqu; dns_rcode rcode; adns_status st; -= 0; + vbuf tempvb; + byte *newquery, *rrsdata; + parseinfo pai; if (dglen>3; + flg_tc= f1&0x02; + flg_rd= f1&0x01; flg_ra= f2&0x80; + rcode= (f2&0x0f); - 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); + cname_here= 0; + + if (!flg_qr) { + adns__diag(ads,serv,0,"server sent us a query, not a response"); 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); + if (opcode) { + adns__diag(ads,serv,0,"server sent us unknown opcode %d (wanted 0=QUERY)",opcode); 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; - } + qu= 0; + /* See if we can find the relevant query, or leave qu=0 otherwise ... */ - rcode= (f1&0x0f); + if (qdcount == 1) { + for (qu= viatcp ? ads->tcpw.head : ads->udpw.head; qu; qu= nqu) { + nqu= qu->next; + if (qu->id != id) continue; + if (dglen < qu->query_dglen) continue; + if (memcmp(qu->query_dgram+DNS_HDRSIZE, + dgram+DNS_HDRSIZE, + qu->query_dglen-DNS_HDRSIZE)) + continue; + if (viatcp) { + assert(qu->state == query_tcpw); + } else { + assert(qu->state == query_tosend); + if (!(qu->udpsent & (1<tcpw,qu); + else LIST_UNLINK(ads->udpw,qu); + } + } + + /* If we're going to ignore the packet, we return as soon as we have + * failed the query (if any) and printed the warning message (if + * any). + */ 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); + adns__warn(ads,serv,qu,"server cannot understand our query (Format Error)"); + if (qu) adns__query_fail(qu,adns_s_rcodeformaterror); return; case rcode_servfail: - adns__query_fail(ads,qu,adns_s_servfail); + if (qu) adns__query_fail(qu,adns_s_rcodeservfail); + else adns__warn(ads,serv,qu,"server failure on unidentifiable query"); return; case rcode_notimp: - adns__warn(ads,serv,"server claims not to implement our query"); - adns__query_fail(ads,qu,adns_s_notimplemented); + adns__warn(ads,serv,qu,"server claims not to implement our query"); + if (qu) adns__query_fail(qu,adns_s_rcodenotimplemented); return; case rcode_refused: - adns__warn(ads,serv,"server refused our query"); - adns__query_fail(ads,qu,adns_s_refused); + adns__warn(ads,serv,qu,"server refused our query"); + if (qu) adns__query_fail(qu,adns_s_rcoderefused); return; default: - adns__warn(ads,serv,"server gave unknown response code %d",rcode); - adns__query_fail(ads,qu,adns_s_reasonunknown); + adns__warn(ads,serv,qu,"server gave unknown response code %d",rcode); + if (qu) adns__query_fail(qu,adns_s_rcodeunknown); return; } + if (!qu) { + if (!qdcount) { + adns__diag(ads,serv,0,"server sent reply without quoting our question"); + } else if (qdcount>1) { + adns__diag(ads,serv,0,"server claimed to answer %d questions with one message", + qdcount); + } else if (ads->iflags & adns_if_debug) { + adns__vbuf_init(&tempvb); + adns__debug(ads,serv,0,"reply not found, id %02x, query owner %s", + id, adns__diag_domain(ads,serv,0,&tempvb,dgram,dglen,DNS_HDRSIZE)); + adns__vbuf_free(&tempvb); + } + return; + } + + /* We're definitely going to do something with this packet and this query now. */ + + anstart= qu->query_dglen; + arstart= -1; + /* 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; + cbyte= anstart; for (rri= 0; rricnameoff >= 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); + st= adns__findrr(qu,serv, dgram,dglen,&cbyte, + &rrtype,&rrclass,&ttl, &rdlength,&rdstart, + &ownermatched); + if (st) { adns__query_fail(qu,st); return; } 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)", + 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) { - 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"); + adns__debug(ads,serv,qu,"ignoring RR with an unexpected owner %s", + adns__diag_domain(ads,serv,qu, &qu->vb, dgram,dglen,rrstart)); } 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. - */ + if (rrtype == adns_r_cname && + (qu->typei->type & adns__rrt_typemask) != adns_r_cname) { + if (qu->flags & adns_qf_cname_forbid) { + adns__query_fail(qu,adns_s_prohibitedcname); + return; + } else if (qu->cname_dgram) { /* Ignore second and subsequent CNAME(s) */ + adns__debug(ads,serv,qu,"allegedly canonical name %s is actually alias for %s", + qu->answer->cname, + adns__diag_domain(ads,serv,qu, &qu->vb, dgram,dglen,rdstart)); + adns__query_fail(qu,adns_s_prohibitedcname); + return; + } else if (wantedrrs) { /* Ignore CNAME(s) after RR(s). */ + adns__debug(ads,serv,qu,"ignoring CNAME (to %s) coexisting with RR", + adns__diag_domain(ads,serv,qu, &qu->vb, dgram,dglen,rdstart)); + } else { + qu->cname_begin= rdstart; + qu->cname_dglen= dglen; + st= adns__parse_domain(ads,serv,qu, &qu->vb, + qu->flags & adns_qf_quotefail_cname ? 0 : pdf_quoteok, + dgram,dglen, &rdstart,rdstart+rdlength); + if (!qu->vb.used) goto x_truncated; + if (st) { adns__query_fail(qu,st); return; } + l= strlen(qu->vb.buf)+1; + qu->answer->cname= adns__alloc_preserved(qu,l); + if (!qu->answer->cname) { adns__query_fail(qu,adns_s_nomemory); return; } + + qu->cname_dgram= adns__alloc_mine(qu,dglen); + memcpy(qu->cname_dgram,dgram,dglen); + + memcpy(qu->answer->cname,qu->vb.buf,l); + cname_here= 1; + adns__update_expires(qu,ttl,now); + /* 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); + adns__debug(ads,serv,qu,"ignoring answer RR with irrelevant type %d",rrtype); } } - /* If we got here then the answer section is intact. */ + /* We defer handling truncated responses here, in case there was a CNAME + * which we could use. + */ + if (flg_tc) goto x_truncated; + 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; + foundsoa= 0; soattl= 0; foundns= 0; for (rri= 0; rriflags & adns_qf_search) { + adns__search_next(ads,qu,now); + } else { + adns__query_fail(qu,adns_s_nxdomain); + } + return; + } if (foundsoa || !foundns) { /* Aha ! A NODATA response, good. */ - adns__query_finish(ads,qu,adns_s_nodata); + adns__update_expires(qu,soattl,now); + adns__query_fail(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. + * 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->cnameoff != -1) { cname_recurse(ads,qu,0); return; } + if (cname_here) goto x_restartquery; /* 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,"server is not willing to do recursive lookups for us"); - adns__query_fail(ads,qu,adns_s_norecurse); - return; + adns__diag(ads,serv,qu,"server is not willing to do recursive lookups for us"); + adns__query_fail(qu,adns_s_norecurse); + } else { + adns__diag(ads,serv,qu,"server claims to do recursion, but gave us a referral"); + adns__query_fail(qu,adns_s_invalidresponse); } - 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); + qu->answer->rrs.untyped= adns__alloc_interim(qu,qu->typei->rrsz*wantedrrs); + if (!qu->answer->rrs.untyped) { adns__query_fail(qu,adns_s_nomemory); return; } + typei= qu->typei; cbyte= anstart; - currentrrs= 0; - arstart= -1; - for (rri=0; rrianswer->rrs.bytes; + + pai.ads= qu->ads; + pai.qu= qu; + pai.serv= serv; + pai.dgram= dgram; + pai.dglen= dglen; + pai.nsstart= nsstart; + pai.nscount= nscount; + pai.arcount= arcount; + pai.now= now; + + for (rri=0, nrrs=0; rritypei->type & adns__rrt_typemask)) + rrtype != (qu->typei->type & adns__rrt_typemask) || + !ownermatched) continue; - assert(currentrrstypei->get_fn(ads,qu,serv, dgram,dglen, &rdstart,rdstart+rdlength, - nsstart,arcount,&arstart, qu->rrsoff,¤trrs); - if (st) { adns__query_fail(ads,qu,st); return; } - if (currentrrs==-1) goto x_truncated; + adns__update_expires(qu,ttl,now); + st= typei->parse(&pai, rdstart,rdstart+rdlength, rrsdata+nrrs*typei->rrsz); + if (st) { adns__query_fail(qu,st); return; } + if (rdstart==-1) goto x_truncated; + nrrs++; } + assert(nrrs==wantedrrs); + qu->answer->nrrs= nrrs; /* This may have generated some child queries ... */ if (qu->children.head) { - qu->state= query_child; + qu->state= query_childw; LIST_LINK_TAIL(ads->childw,qu); return; } - - adns__query_finish(ads,qu,adns_s_ok); + adns__query_done(qu); return; -x_truncated: + x_truncated: + if (!flg_tc) { - adns__diag(ads,serv,"server sent datagram which points outside itself"); - adns__query_fail(ads,qu,adns_s_serverfaulty); + adns__diag(ads,serv,qu,"server sent datagram which points outside itself"); + adns__query_fail(qu,adns_s_invalidresponse); 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); + + x_restartquery: + if (qu->cname_dgram) { + st= adns__mkquery_frdgram(qu->ads,&qu->vb,&qu->id, + qu->cname_dgram, qu->cname_dglen, qu->cname_begin, + qu->typei->type, qu->flags); + if (st) { adns__query_fail(qu,st); return; } + + newquery= realloc(qu->query_dgram,qu->vb.used); + if (!newquery) { adns__query_fail(qu,adns_s_nomemory); return; } + + qu->query_dgram= newquery; + qu->query_dglen= qu->vb.used; + memcpy(newquery,qu->vb.buf,qu->vb.used); + } + + if (qu->state == query_tcpw) qu->state= query_tosend; + qu->retries= 0; + adns__reset_preserved(qu); + adns__query_send(qu,now); }