#include "internal.h"
-typedef enum {
- rcode_noerror,
- rcode_formaterror,
- rcode_serverfail,
- rcode_nxdomain,
- rcode_notimp,
- rcode_refused
-} dns_rcode;
-
-void adns__procdgram(adns_state ads, const byte *dgram, int len, int serv) {
- unsigned char *rpp;
+static void cname_recurse(adns_state ads, adns_query qu, adns_queryflags xflags) {
+ abort(); /* FIXME */
+}
+
+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 anstart, nsstart, arstart;
+ int currentrrs;
+ adns_query qu, nqu;
+ dns_rcode rcode;
+ adns_status st;
+= 0;
- if (len<12) {
- adns__diag(ads,serv,"received datagram too short for message header (%d)",len);
+ if (dglen<DNS_HDRSIZE) {
+ adns__diag(ads,serv,"received datagram too short for message header (%d)",dglen);
return;
}
- id= GFREPLYW;
- f1= GFREPLYB;
- f2= GFREPLYB;
- qdcount= GFREPLYW;
- ancount= GFREPLYW;
- nscount= GFREPLYW;
- arcount= GFREPLYW;
+ GET_W(cbyte,id);
+ GET_B(cbyte,f1);
+ GET_B(cbyte,f2);
+ GET_W(cbyte,qdcount);
+ GET_W(cbyte,ancount);
+ GET_W(cbyte,nscount);
+ GET_W(cbyte,arcount);
+ assert(cbyte == DNS_HDRSIZE);
+
+ flg_tc= f1&0x20;
+ flg_ra= f2&0x80;
if (f1&0x80) {
adns__diag(ads,serv,"server sent us a query, not a response");
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+12,rpp,qu->querylen-12)) 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);
return;
}
- 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);
- 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;
}
- switch (f1&0x0f) {
- case 0: /* NOERROR */
+
+ rcode= (f1&0x0f);
+ switch (rcode) {
+ case rcode_noerror:
+ case rcode_nxdomain:
break;
- case 1: /* Format error */
- adns__diag(ads,serv,"server cannot understand our query (Format Error)");
+ case rcode_formaterror:
+ adns__warn(ads,serv,"server cannot understand our query (Format Error)");
adns__query_fail(ads,qu,adns_s_serverfaulty);
return;
- case 2: /* Server failure */
- adns__query_fail(ads,qu,adns_s_serverfailure);
+ case rcode_servfail:
+ adns__query_fail(ads,qu,adns_s_servfail);
return;
- case 3: /* Name Error */
-
- qr= f1&0x80;
-
-
- adns__diag(ads,serv,"received datagram size %d",len);
+ case rcode_notimp:
+ adns__warn(ads,serv,"server claims not to implement our query");
+ adns__query_fail(ads,qu,adns_s_notimplemented);
+ return;
+ case rcode_refused:
+ adns__warn(ads,serv,"server refused our query");
+ adns__query_fail(ads,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);
+ return;
+ }
+
+ /* 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;
+ for (rri= 0; rri<ancount; rri++) {
+ rrstart= cbyte;
+ if (qu->cnameoff >= 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);
+ 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)",
+ 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");
+ }
+ 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.
+ */
+ } else if (rrtype == (qu->typei->type & adns__rrt_typemask)) {
+ wantedrrs++;
+ } else {
+ adns__debug(ads,serv,"ignoring answer RR with irrelevant type %d",rrtype);
+ }
+ }
+
+ /* If we got here then the answer section is intact. */
+ 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;
+ for (rri= 0; rri<nscount; rri++) {
+ rrstart= cbyte;
+ st= adns__get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte,
+ &rrtype,&rrclass, &rdlength,&rdstart, 0,0,0,0);
+ if (st) { adns__query_fail(ads,qu,st); return; }
+ 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; }
+ }
+
+ 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->cnameoff != -1) { cname_recurse(ads,qu,0); 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_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);
+
+ cbyte= anstart;
+ currentrrs= 0;
+ arstart= -1;
+ for (rri=0; rri<ancount; rri++) {
+ st= adns__get_rr_temp(ads,qu,serv, dgram,dglen,&cbyte,
+ &rrtype,&rrclass, &rdlength,&rdstart, 0,0,0,0);
+ assert(!st); assert(rrtype != -1);
+ if (rrclass != DNS_CLASS_IN ||
+ rrtype != (qu->typei->type & adns__rrt_typemask))
+ continue;
+ assert(currentrrs<wantedrrs);
+ st= qu->typei->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;
+ }
+
+ /* This may have generated some child queries ... */
+ if (qu->children.head) {
+ qu->state= query_child;
+ LIST_LINK_TAIL(ads->childw,qu);
+ return;
+ }
+
+ adns__query_finish(ads,qu,adns_s_ok);
+ return;
+
+x_truncated:
+ if (!flg_tc) {
+ adns__diag(ads,serv,"server sent datagram which points outside itself");
+ adns__query_fail(ads,qu,adns_s_serverfaulty);
+ 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);
}
~ianmdlvl / adns.git / blobdiff