}
}
+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;
+ 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
cbyte= *cbyte_io;
sused= qu->ans.used;
*domain_r= 0;
+ namelen= 0;
for (;;) {
- if (cbyte>=max) goto x_truncated;
- lablen= GET_B(cbyte);
+ st= get_label(dgram,dglen,&max, &cbyte,&lablen,&labstart,&namelen);
+ if (st) return st;
+ if (lablen<0) goto x_truncated;
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))
+ if (!vbuf__append_quoted1035(&qu->ans,dgram+labstart,lablen))
return adns_s_nolocalmem;
} else {
- if (!ctype_isalpha(dgram[cbyte])) return adns_s_invaliddomain;
+ if (!ctype_isalpha(dgram[labstart])) return adns_s_invaliddomain;
for (i= cbyte+1; i<cbyte+lablen; i++) {
ch= dgram[cbyte];
if (ch != '-' && !ctype_isalpha(ch) && !ctype_isdigit(ch))
return adns_s_invaliddomain;
}
- if (!adns__vbuf_append(&qu->ans,dgram+cbyte,lablen))
+ if (!adns__vbuf_append(&qu->ans,dgram+labstart,lablen))
return adns_s_nolocalmem;
}
}
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,
+ 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;
+ 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;
- st= get_domain_temp(ads,qu,serv,dgram,dglen,&cbyte,dglen,owner_r);
- if (st) return st;
+ 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); if (type_r) *type_r= tmp;
- GET_W(cbyte,tmp); if (class_r) *class_r= tmp;
+ 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;
return adns_s_ok;
x_truncated:
- *owner_r= 0; return 0;;
+ *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;
+ int cbyte, anstart, rrstart, lablen, wantedrrs, get_t, cnamestart;
cbyte= 0;
GET_W(cbyte,arcount);
assert(cbyte == DNS_HDR_SIZE);
+ flg_ra= f2&0x80;
+
if (f1&0x80) {
adns__diag(ads,serv,"server sent us a query, not a response");
return;
wantedrrs= 0;
for (rri= 0; rri<ancount; rri++) {
rrstart= cbyte;
- st= get_rr_temp(ads,qu,serv,
- dgram,dglen,
- &cbyte,
- &rrtype,&rrclass,&rdlength,&cowner);
+ if (qu->cname) {
+ 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);
+ if (rrtype == -1) goto x_truncated;
+
if (rrclass != DNS_CLASS_IN) {
- adns__diag(ads,serv,"ignoring RR with wrong class %d (expected IN=%d)",
+ adns__diag(ads,serv,"ignoring answer RR with wrong class %d (expected IN=%d)",
rrclass,DNS_CLASS_IN);
continue;
}
- if (strcmp_quoted1035(cowner, qu->cname ? qu->cname : qu->owner)) {
- adns__debug(ads,serv,"ignoring answer RR with irrelevant owner \"%s\"",cowner);
+ 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);
+ }
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 we find the answer section truncated after this point we restart
- * the query at the CNAME; otherwise we can use it as-is.
- */
+ 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)) {
wantedrrs++;
} else {
/* Oops, NODATA or NXDOMAIN or perhaps a referral (which would be a problem) */
if (rcode == rcode_nxdomain) {
- adnns__query_finish(ads,qu,adns_s_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= get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte,
+ &rrtype,&rrclass, &rdlength,&rdstart, 0,0,0,0);
+ if (st) return st;
+ 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; }
}
- } else {
-
-
- if (!(f2&0x80)) {
- adns__diag(ads,serv,"server is not willing to do recursive lookups for us");
- adns__query_fail(ads,qu,adns_s_norecurse);
+
+ 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->cname) {
+ cname_recurse(ads,qu);
+ 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_serverfault);
return;
}
+ /* Now, we have some RRs which we wanted. */
+ rrs=
+
+ }
+ } else {
+
+{ truncated(ads,qu,flg_ra); return; }
) {
if (type
adns__diag(ads,serv,"received datagram size %d",len);
}
+
+ 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
+
+
~ianmdlvl / adns.git / blobdiff