X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git;a=blobdiff_plain;f=src%2Freply.c;h=246d52d44fe0a796018b0b15666be9710909fbe6;hp=b6218c1673e94ee7f48a715d5a10126bed44a065;hb=914a5ff5342e43d8a2378b1f0f65057ef084fe20;hpb=b9de380c1e587b6c5828cb9de796746024946880 diff --git a/src/reply.c b/src/reply.c index b6218c1..246d52d 100644 --- a/src/reply.c +++ b/src/reply.c @@ -1,144 +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" - -typedef enum { - rcode_noerror, - rcode_formaterror, - rcode_servfail, - rcode_nxdomain, - rcode_notimp, - rcode_refused -} dns_rcode; - -#define GETIL_B(cb) (dgram[*(cb)++]) -#define GET_B(cb,tv) ((tv)= GETIL_B((cb))) -#define GET_W(cb,tv) ((tv)=0, (tv)|=(GETIL_B((cb))<<8), (tv)|=GETIL_B(cb), (tv)) - -static void vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len) { - char qbuf[10]; - int i; - - while (len) { - qbuf[0]= 0; - for (i=0; i= 127) { - sprintf(qbuf,"\\%03o",ch); - break; - } - } - if (!adns__vbuf_append(vb,buf,i) || !adns__vbuf_append(vb,qbuf,strlen(qbuf))) - return adns_s_nolocalmem; - buf+= i; len-= i; - } -} - -static adns_status get_domain_perm(adns_state ads, adns_query qu, int serv, - const byte *dgram, int dglen, - int *cbyte_io, int max, char **domain_r) { - /* Returns 0 for OK (*domain_r set) or truncated (*domain_r null) - * or any other adns_s_* value. - */ - int cbyte, sused, lablen; +#include - /* If we follow a pointer we set cbyte_io to 0 to indicate that - * we've lost our original starting and ending points; we don't - * put the end of the pointed-to thing into the original *cbyte_io. - */ - cbyte= *cbyte_io; - sused= qu->ans.used; - *domain_r= 0; - for (;;) { - if (cbyte>=max) goto x_truncated; - lablen= GET_B(cbyte); - if (!lablen) break; - if (lablen&0x0c000) { - if ((lablen&0x0c000) != 0x0c0000) return adns_s_unknownreply; - if (cbyte_io) { *cbyte_io= cbyte; cbyte_io= 0; } - cbyte= (lablen&0x3fff) + DNS_HDR_SIZE; - max= dglen; - continue; - } - if (cbyte+lablen>=max) bgoto x_truncated; - if (qu->ans.used != sused) - if (!adns__vbuf_append(&qu->ans,".",1)) return adns_s_nolocalmem; - if (qu->flags & adns_qf_anyquote) { - if (!vbuf__append_quoted1035(&qu->ans,dgram+cbyte,lablen)) - return adns_s_nolocalmem; - } else { - if (!ctype_isalpha(dgram[cbyte])) return adns_s_invaliddomain; - for (i= cbyte+1; ians,dgram+cbyte,lablen)) - return adns_s_nolocalmem; - } - } - if (cbyte_io) *cbyte_io= cbyte; - if (!adns__vbuf_append(&qu->ans,"",1)) return adns_s_nolocalmem; - *domain_r= qu->ans.buf+sused; - return adns_s_ok; - - x_truncated: - return cbyte_io ? -1 : adns_s_serverfaulty; -} +#include "internal.h" -static adns_status get_domain_temp(adns_state ads, adns_query qu, int serv, - const byte *dgram, int dglen, - int *cbyte_io, int max, char **domain_r) { - int sused; +void adns__procdgram(adns_state ads, const byte *dgram, int dglen, + 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 ownermatched, l, nrrs; + unsigned long ttl, soattl; + const typeinfo *typei; + adns_query qu, nqu; + dns_rcode rcode; adns_status st; - - sused= qu->ans.used; - st= get_domain_perm(ads,qu,serv,dgram,dglen,cbyte_io,max,domain_r); - qu->ans.used= sused; - return st; -} - -/* fixme: sensible comparison of owners */ - -static adns_status get_rr_temp(adns_state ads, adns_query qu, int serv, - const byte *dgram, int dglen, - int *cbyte_io, - int *type_r, int *class_r, int *rdlen_r, int *rdstart_r, - char **owner_r) { - int cbyte, tmp, rdlen; - - cbyte= *cbyte_io; - st= get_domain_temp(ads,qu,serv,dgram,dglen,&cbyte,dglen,owner_r); - if (st) return st; - - if (cbyte+10>len) goto x_truncated; - GET_W(cbyte,tmp); if (type_r) *type_r= tmp; - GET_W(cbyte,tmp); if (class_r) *class_r= tmp; - cbyte+= 4; /* we skip the TTL */ - GET_W(cbyte,rdlen); if (rdlen_r) *rdlen_r= tmp; - if (rdstart_r) *rdstart_r= cbyte; - cbyte+= rdlen; - if (cbyte>dglen) goto x_truncated; - *cbyte_io= cbyte; - return adns_s_ok; - - x_truncated: - *owner_r= 0; return 0;; -} - -void adns__procdgram(adns_state ads, const byte *dgram, int dglen, int serv) { - int cbyte, anstart, rrstart, lablen, wantedrrs, get_t; - - cbyte= 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"); + cname_here= 0; + + if (!flg_qr) { + adns__diag(ads,serv,0,"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); + if (opcode) { + adns__diag(ads,serv,0,"server sent us unknown opcode %d (wanted 0=QUERY)",opcode); return; } if (!qdcount) { - adns__diag(ads,serv,"server sent reply without quoting our question"); + adns__diag(ads,serv,0,"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", + adns__diag(ads,serv,0,"server claimed to answer %d questions with one message", qdcount); return; } - for (qu= ads->timew; qu= nqu; qu++) { + for (qu= viatcp ? ads->tcpw.head : ads->udpw.head; qu; qu= nqu) { nqu= qu->next; if (qu->id != id) continue; - if (len < qu->querylen) continue; - if (memcmp(qu->querymsg+DNSHDRSIZE,dgram+DNSHDRSIZE,qu->querylen-DNSHDRSIZE)) + 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<querylen; if (!qu) { - adns__debug(ads,serv,"reply not found (id=%02x)",id); - return; - } - if (!(f1&0x01)) { - adns__diag(ads,serv,"server thinks we didn't ask for recursive lookup"); - adns__query_fail(ads,qu,adns_s_serverfaulty); + 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; } + anstart= qu->query_dglen; + arstart= -1; - rcode= (f1&0x0f); + if (viatcp) LIST_UNLINK(ads->tcpw,qu); + else LIST_UNLINK(ads->udpw,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,"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)"); + adns__query_fail(qu,adns_s_rcodeformaterror); return; - case rcode_servfail; - adns__query_fail(ads,qu,adns_s_serverfailure); + case rcode_servfail: + adns__query_fail(qu,adns_s_rcodeservfail); 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"); + 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"); + 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); + adns__query_fail(qu,adns_s_rcodeunknown); return; } @@ -214,85 +146,212 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, int serv) { * If it has any CNAMEs we stuff them in the answer. */ wantedrrs= 0; + cbyte= anstart; for (rri= 0; rricname ? qu->cname : qu->owner)) { - adns__debug(ads,serv,"ignoring answer RR with irrelevant owner \"%s\"",cowner); + 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, &qu->vb, dgram,dglen,rrstart)); + } continue; } - if (!qu->cname && - (qu->type & adns__rrt_typemask) != adns_cname && - rrtype == adns_cname) { /* Ignore second and subsequent CNAMEs */ - qu->cname= get_domain_perm(ads,qu,dgram,len,rdstart,rdstart+rdlength); + 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_quoteok_cname ? pdf_quoteok : 0, + 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; otherwise we can use it as-is. + * 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->type & adns__rrt_typemask)) { + } + } 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) */ + + /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */ + 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; } - /* RFC2308: NODATA has _either_ a SOA _or_ _no_ NS records in authority section */ - for (rri= 0; rri dgend) { truncated(ads,qu,f1); return; } + /* Now, we have some RRs which we wanted. */ + + 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; + rrsdata= qu->answer->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) || + !ownermatched) + continue; + 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++; } - for + assert(nrrs==wantedrrs); + qu->answer->nrrs= nrrs; - /* Look for CNAMEs in the answer section */ + /* This may have generated some child queries ... */ + if (qu->children.head) { + qu->state= query_childw; + LIST_LINK_TAIL(ads->childw,qu); + return; + } + adns__query_done(qu); + return; + x_truncated: + + if (!flg_tc) { + adns__diag(ads,serv,qu,"server sent datagram which points outside itself"); + adns__query_fail(qu,adns_s_invalidresponse); + return; } + qu->flags |= adns_qf_usevc; + 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; } - adns__diag(ads,serv,"server refused our query"); + newquery= realloc(qu->query_dgram,qu->vb.used); + if (!newquery) { adns__query_fail(qu,adns_s_nomemory); return; } - case rcode_ - - case 0: /* NOERROR - break; - case 1: /* Format error */ - case 3: /* Name Error */ - - qr= f1&0x80; + qu->query_dgram= newquery; + qu->query_dglen= qu->vb.used; + memcpy(newquery,qu->vb.buf,qu->vb.used); + } - - adns__diag(ads,serv,"received datagram size %d",len); - + if (qu->state == query_tcpw) qu->state= query_tosend; + qu->retries= 0; + adns__reset_preserved(qu); + adns__query_send(qu,now); }