X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=adns.git;a=blobdiff_plain;f=src%2Freply.c;h=0379ca441ff52f90feefdce6cf3dc333c7b808a7;hp=90314763f656b1f6a9cdaef4f08818b824593a83;hb=fcf2b4e1faf22accb6184cca595aaee602839868;hpb=4b707d8b1701aec2cec7431d4656f771b96a9f00 diff --git a/src/reply.c b/src/reply.c index 9031476..0379ca4 100644 --- a/src/reply.c +++ b/src/reply.c @@ -3,11 +3,16 @@ * - main handling and parsing routine for received datagrams */ /* - * This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson + * This file is part of adns, which is + * Copyright (C) 1997-2000,2003,2006,2014-2016 Ian Jackson + * Copyright (C) 2014 Mark Wooding + * Copyright (C) 1999-2000,2003,2006 Tony Finch + * Copyright (C) 1991 Massachusetts Institute of Technology + * (See the file INSTALL for full details.) * * 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) + * the Free Software Foundation; either version 3, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, @@ -16,23 +21,22 @@ * 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. + * along with this program; if not, write to the Free Software Foundation. */ #include -#include #include "internal.h" void adns__procdgram(adns_state ads, const byte *dgram, int dglen, - int serv, struct timeval now) { + 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; + int anstart, nsstart; + int ownermatched, l, nrrs, restartfrom; + unsigned long ttl, soattl; const typeinfo *typei; adns_query qu, nqu; dns_rcode rcode; @@ -42,7 +46,8 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, parseinfo pai; if (dglen1) { - adns__diag(ads,serv,0,"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->query_dglen) continue; - if (memcmp(qu->query_dgram+DNS_HDRSIZE, - dgram+DNS_HDRSIZE, - qu->query_dglen-DNS_HDRSIZE)) - continue; - break; - } - if (!qu) { - 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); + + qu= 0; + /* See if we can find the relevant query, or leave qu=0 otherwise ... */ + + 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); } - return; } - anstart= qu->query_dglen; - arstart= -1; - - LIST_UNLINK(ads->timew,qu); - /* We're definitely going to do something with this query now */ + /* 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,qu,"server cannot understand our query (Format Error)"); - adns__query_fail(qu,adns_s_rcodeformaterror); + 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(qu,adns_s_rcodeservfail); + if (qu) adns__query_fail(qu,adns_s_rcodeservfail); + else adns__debug(ads,serv,qu,"server failure on unidentifiable query"); return; case rcode_notimp: adns__warn(ads,serv,qu,"server claims not to implement our query"); - adns__query_fail(qu,adns_s_rcodenotimplemented); + if (qu) adns__query_fail(qu,adns_s_rcodenotimplemented); return; case rcode_refused: - adns__warn(ads,serv,qu,"server refused our query"); - adns__query_fail(qu,adns_s_rcoderefused); + adns__debug(ads,serv,qu,"server refused our query"); + if (qu) adns__query_fail(qu,adns_s_rcoderefused); return; default: adns__warn(ads,serv,qu,"server gave unknown response code %d",rcode); - adns__query_fail(qu,adns_s_rcodeunknown); + 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; + /* 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; + restartfrom= -1; cbyte= anstart; for (rri= 0; rriiflags & 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)); + adns__diag_domain(ads,serv,qu, &qu->vb, + dgram,dglen,rrstart)); } continue; } - if (rrtype == adns_r_cname && /* fixme - implement adns_qf_nocname */ - (qu->typei->type & adns__rrt_typemask) != adns_r_cname) { + if (rrtype == adns_r_cname && + (qu->answer->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 CNAMEs */ + } 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, + 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_interim(qu,l); - if (!qu->answer->cname) { adns__query_fail(qu,adns_s_nomemory); return; } + 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 { - adns__debug(ads,serv,qu,"ignoring duplicate CNAME (%s, as well as %s)", - adns__diag_domain(ads,serv,qu, &qu->vb, dgram,dglen,rdstart), - qu->answer->cname); } - } else if (rrtype == (qu->typei->type & adns__rrt_typemask)) { + } else if (rrtype == (qu->answer->type & adns_rrt_typemask)) { + if (restartfrom==-1) restartfrom= rri; wantedrrs++; } else { - adns__debug(ads,serv,qu,"ignoring answer RR with irrelevant type %d",rrtype); + adns__debug(ads,serv,qu,"ignoring answer RR" + " with irrelevant type %d",rrtype); } } @@ -202,33 +246,43 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, nsstart= cbyte; if (!wantedrrs) { - /* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */ - - if (rcode == rcode_nxdomain) { - adns__query_fail(qu,adns_s_nxdomain); - return; - } + /* 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; foundns= 0; + /* 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 && !qu->cname_dgram) { + adns__search_next(ads,qu,now); + } else { + adns__query_fail(qu,adns_s_nxdomain); + } + return; + } if (foundsoa || !foundns) { /* Aha ! A NODATA response, good. */ + adns__update_expires(qu,soattl,now); adns__query_fail(qu,adns_s_nodata); return; } @@ -241,14 +295,17 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, 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,qu,"server is not willing to do recursive lookups for us"); + 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"); + if (!flg_rd) + adns__diag(ads,serv,qu,"server thinks" + " we didn't ask for recursive lookup"); + else + adns__debug(ads,serv,qu,"server claims to do recursion," + " but gave us a referral"); adns__query_fail(qu,adns_s_invalidresponse); } return; @@ -256,8 +313,11 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, /* 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; } + qu->answer->rrs.untyped= adns__alloc_interim(qu,qu->answer->rrsz*wantedrrs); + if (!qu->answer->rrs.untyped) { + adns__query_fail(qu,adns_s_nomemory); + return; + } typei= qu->typei; cbyte= anstart; @@ -273,16 +333,20 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, pai.arcount= arcount; pai.now= now; + assert(restartfrom>=0); for (rri=0, nrrs=0; rritypei->type & adns__rrt_typemask) || + if (rri < restartfrom || + rrclass != DNS_CLASS_IN || + rrtype != (qu->answer->type & adns_rrt_typemask) || !ownermatched) continue; - st= typei->parse(&pai, rdstart,rdstart+rdlength, rrsdata+nrrs*typei->rrsz); + adns__update_expires(qu,ttl,now); + st= typei->parse(&pai, rdstart,rdstart+rdlength, + rrsdata+nrrs*qu->answer->rrsz); if (st) { adns__query_fail(qu,st); return; } if (rdstart==-1) goto x_truncated; nrrs++; @@ -292,11 +356,10 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, /* 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_done(qu); return; @@ -310,11 +373,10 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, 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); + qu->cname_dgram,qu->cname_dglen,qu->cname_begin, + qu->answer->type, qu->flags); if (st) { adns__query_fail(qu,st); return; } newquery= realloc(qu->query_dgram,qu->vb.used); @@ -325,6 +387,8 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, memcpy(newquery,qu->vb.buf,qu->vb.used); } - adns__reset_cnameonly(qu); - adns__query_udp(qu,now); + if (qu->state == query_tcpw) qu->state= query_tosend; + qu->retries= 0; + adns__reset_preserved(qu); + adns__query_send(qu,now); }