X-Git-Url: https://git.distorted.org.uk/~mdw/adns/blobdiff_plain/0ba0614a998909d8b4f51988d7a8af3ba369a5d9..61b923b38be853072bce998602c8921d469f189e:/src/reply.c diff --git a/src/reply.c b/src/reply.c index 7158668..f98540c 100644 --- a/src/reply.c +++ b/src/reply.c @@ -1,202 +1,47 @@ -/**/ +/* + * reply.c + * - main handling and parsing routine for received datagrams + */ +/* + * This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson + * + * 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_label(const byte *dgram, int dglen, int *max_io, - int *cbyte_io, int *lablen_r, int *labstart_r, - int *namelen_io) { - /* If succeeds, *lablen_r may be set to -1 to indicate truncation/overrun */ - int max, cbyte, lablen, namelen; - - max= *max_io; - cbyte= *cbyte_io; - - for (;;) { - if (cbyte+2 > max) goto x_truncated; - GET_W(cbyte,lablen); - if (!(lablen & 0x0c000)) break; - if ((lablen & 0x0c000) != 0x0c000) return adns_s_unknownreply; - if (cbyte_io) { *cbyte_io= cbyte; cbyte_io= 0; } - cbyte= dgram+DNS_HDR_SIZE+(lablen&0x3fff); - *max_io= max= dglen; - } - if (labstart_r) *labstart_r= cbyte; - if (lablen) { - namelen= *namelen_io; - if (namelen) namelen++; - namelen+= lablen; - if (namelen > DNS_MAXDOMAIN) return adns_s_domaintoolong; - *namelen_io= namelen; - cbyte+= lablen; - if (cbyte > max) goto x_truncated; - } - if (cbyte_io) *cbyte_io= cbyte; - *lablen_r= lablen; - return adns_s_ok; - - x_truncated: - *lablen_r= -1; - return adns_s_ok; -} - -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, namelen; - - /* 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; - namelen= 0; - for (;;) { - st= get_label(dgram,dglen,&max, &cbyte,&lablen,&labstart,&namelen); - if (st) return st; - if (lablen<0) goto x_truncated; - if (!lablen) break; - 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+labstart,lablen)) - return adns_s_nolocalmem; - } else { - if (!ctype_isalpha(dgram[labstart])) return adns_s_invaliddomain; - for (i= cbyte+1; ians,dgram+labstart,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; +static void cname_recurse(adns_query qu, adns_queryflags xflags) { + abort(); /* FIXME */ } -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, struct timeval now) { + int cbyte, rrstart, wantedrrs, rri, foundsoa, foundns; + int id, f1, f2, qdcount, ancount, nscount, arcount; + int flg_ra, flg_rd, flg_tc, flg_qr, opcode; + int rrtype, rrclass, rdlength, rdstart, ownermatched, l; + int anstart, nsstart, arstart; + 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; -} - -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, - const byte *eo_dgram, int eo_dglen, int eo_cbyte, - int *eo_matched_r) { - /* _s_ok can have *type_r == -1 and other output invalid, for truncation - * type_r and class_r must be !0, other _r may be 0. - * eo_dgram==0 for no comparison, otherwise all eo_ must be valid. - */ - int cbyte, tmp, rdlen, mismatch; - int max, lablen, labstart, namelen; - int eo_max, eo_lablen, eo_labstart, eo_namelen; - - cbyte= *cbyte_io; - mismatch= eo_dgram ? 1 : 0; - - namelen= 0; eo_namelen= 0; - max= dglen; eo_max= eo_dglen; - for (;;) { - st= get_label(dgram,dglen,&max, - &cbyte,&lablen,&labstart,&namelen); - if (st) return st; - if (lablen<0) goto x_truncated; - - if (!mismatch) { - st= get_label(eo_dgram,eo_dglen,&eo_max, - &eo_cbyte,&eo_lablen,&eo_labstart,&eo_namelen); - if (st) return st; - assert(eo_lablen>=0); - if (lablen != eo_lablen) mismatch= 1; - while (!mismatch && lablen-- > 0) { - ch= dgram[labstart++]; if (ctype_isalpha(ch)) ch &= ~32; - eo_ch= eo_dgram[eo_labstart++]; if (ctype_isalpha(eo_ch)) eo_ch &= ~32; - if (ch != eo_ch) mismatch= 1 - } - } - } - if (eo_matched_r) *eo_matched_r= !mismatch; - if (cbyte+10>len) goto x_truncated; - GET_W(cbyte,tmp); *type_r= tmp; - GET_W(cbyte,tmp); *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: - *type_r= -1; - return 0;; -} - -void adns__procdgram(adns_state ads, const byte *dgram, int dglen, int serv) { - int cbyte, anstart, rrstart, lablen, wantedrrs, get_t, cnamestart; - - cbyte= 0; - - if (dglen>3; + flg_tc= f1&0x20; + flg_rd= f1&0x01; flg_ra= f2&0x80; + rcode= (f1&0x0f); + /* fixme: change this to f2 (which is where rcode really is), BUT + * not until we've figured out why the error code is wrong (bad format code 203) + */ - if (f1&0x80) { - adns__diag(ads,serv,"server sent us a query, not a response"); + 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= ads->timew.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; break; } - anstart= qu->querylen; + anstart= qu->query_dglen; 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); + adns__debug(ads,serv,0,"reply not found (id=%02x)",id); return; } - rcode= (f1&0x0f); + 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,"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_serverfaulty); return; - case rcode_servfail; - adns__query_fail(ads,qu,adns_s_serverfailure); + case rcode_servfail: + adns__query_fail(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); + adns__warn(ads,serv,qu,"server claims not to implement our query"); + adns__query_fail(qu,adns_s_notimplemented); 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_refused); 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_reasonunknown); return; } @@ -276,47 +127,55 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, int serv) { wantedrrs= 0; for (rri= 0; rricname) { - st= get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte, - &rrtype,&rrclass,&rdlength,&rdstart, - dgram,dglen,cnamestart, &ownermatched); - } else { - st= get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte, - &rrtype,&rrclass,&rdlength,&rdstart, - qu->querymsg,qu->querylen,DNS_HDR_SIZE, &ownermatched); - } - if (st) adns__query_fail(ads,qu,st); + st= adns__findrr(qu,serv, dgram,dglen,&cbyte, + &rrtype,&rrclass,&rdlength,&rdstart, + &ownermatched); + if (st) adns__query_fail(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)", + adns__diag(ads,serv,qu,"ignoring answer RR with wrong class %d (expected IN=%d)", rrclass,DNS_CLASS_IN); continue; } if (!ownermatched) { - if (ads->iflag & adns_if_debug) { - st= get_domain_temp(ads,qu,serv, dgram,dglen,&rrstart,dglen, &cowner); - if (st) adns__debug(ads,serv,"ignoring RR with an irrelevant owner, code %d",st); - else adns__debug(ads,serv,"ignoring RR with an irrelevant owner \"%s\"",cowner); + 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,qu->flags, + dgram,dglen,rrstart)); } continue; } - if (!qu->cname && - (qu->type & adns__rrt_typemask) != adns_cname && - rrtype == adns_cname) { /* Ignore second and subsequent CNAMEs */ - st= get_domain_perm(ads,qu,serv, dgram,dglen, - &rdstart,rdstart+rdlength,&qu->cname); - if (st) return st; - if (!qu->cname) 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->type & adns__rrt_typemask)) { + if (rrtype == adns_r_cname && + (qu->typei->type & adns__rrt_typemask) != adns_r_cname) { + if (!qu->cname_dgram) { /* Ignore second and subsequent CNAMEs */ + qu->cname_dgram= adns__alloc_mine(qu,dglen); + if (!qu->cname_dgram) return; + qu->cname_begin= rdstart; + qu->cname_dglen= dglen; + st= adns__parse_domain(ads,serv,qu, &qu->vb,qu->flags, + 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) return; + memcpy(qu->answer->cname,qu->vb.buf,l); + /* 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,qu->flags, + dgram,dglen,rdstart), + qu->answer->cname); + } + } 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); } } @@ -327,7 +186,7 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, int serv) { /* 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); + adns__query_fail(qu,adns_s_nxdomain); return; } @@ -335,12 +194,13 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen, int serv) { foundsoa= 0; foundns= 0; for (rri= 0; rricname) { - cname_recurse(ads,qu); - return; - } + if (qu->cname_dgram == dgram) { cname_recurse(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,"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_serverfaulty); } - adns__diag(ads,serv,"server claims to do recursion, but gave us a referral"); - adns__query_fail(ads,qu,adns_s_serverfault); return; } /* Now, we have some RRs which we wanted. */ - rrs= - - } - } else { - -{ truncated(ads,qu,flg_ra); return; } - - ) { - if (type - if (cbyte+lab - if (anstart > dgend) { truncated(ads,qu,f1); return; } - } - for - /* Look for CNAMEs in the answer section */ + qu->answer->rrs.untyped= adns__alloc_interim(qu,qu->typei->rrsz*wantedrrs); + if (!qu->answer->rrs.untyped) return; + + cbyte= anstart; + arstart= -1; + for (rri=0; rritypei->type & adns__rrt_typemask) || + !ownermatched) + continue; + assert(qu->answer->nrrstypei->parse(qu,serv, + dgram,dglen, rdstart,rdstart+rdlength, + qu->answer->rrs.bytes+qu->answer->nrrs*qu->typei->rrsz); + if (st) { adns__query_fail(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__diag(ads,serv,"server refused our query"); - - case rcode_ - - case 0: /* NOERROR - break; - case 1: /* Format error */ - case 3: /* Name Error */ - - qr= f1&0x80; - - - adns__diag(ads,serv,"received datagram size %d",len); -} + adns__query_done(qu); + return; - while ( - switch (type) { - case adns_r_a: - adns_r_a_mf= adns_r_a|adns__qtf_masterfmt, - - adns_r_ns_raw= 2, - adns_r_ns= adns_r_ns_raw|adns__qtf_deref, - adns_r_ns_mf= adns_r_ns_raw|adns__qtf_masterfmt, - - adns_r_cname= 5, - adns_r_cname_mf= adns_r_cname|adns__qtf_masterfmt, - - adns_r_soa_raw= 6, - adns_r_soa= adns_r_soa_raw|adns__qtf_mail822, - adns_r_soa_mf= adns_r_soa_raw|adns__qtf_masterfmt, - - adns_r_null= 10, - adns_r_null_mf= adns_r_null|adns__qtf_masterfmt, - - adns_r_ptr_raw= 12, - adns_r_ptr= adns_r_ptr_raw|adns__qtf_deref, - adns_r_ptr_mf= adns_r_ptr_raw|adns__qtf_masterfmt, - - adns_r_hinfo= 13, - adns_r_hinfo_mf= adns_r_hinfo|adns__qtf_masterfmt, - - adns_r_mx_raw= 15, - adns_r_mx= adns_r_mx_raw|adns__qtf_deref, - adns_r_mx_mf= adns_r_mx_raw|adns__qtf_masterfmt, - - adns_r_txt= 16, - adns_r_txt_mf= adns_r_txt|adns__qtf_masterfmt, - - adns_r_rp_raw= 17, - adns_r_rp= adns_r_rp_raw|adns__qtf_mail822, - adns_r_rp_mf= adns_r_rp_raw|adns__qtf_masterfmt - - + x_truncated: + if (!flg_tc) { + adns__diag(ads,serv,qu,"server sent datagram which points outside itself"); + adns__query_fail(qu,adns_s_serverfaulty); + return; + } + if (qu->cname_dgram) { cname_recurse(qu,adns_qf_usevc); return; } + adns__reset_cnameonly(qu); + qu->flags |= adns_qf_usevc; + adns__query_udp(qu,now); +}