#include "internal.h"
-void adns__procdgram(adns_state ads, const byte *dgram, int len, int serv) {
- /* FIXME do something with incoming datagrams */
+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<len; i++) {
+ ch= buf[i];
+ if (ch == '.' || ch == '"' || ch == '(' || ch == ')' ||
+ ch == '@' || ch == ';' || ch == '$') {
+ sprintf(qbuf,"\\%c",ch);
+ break;
+ } else if (ch <= ' ' || ch >= 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; 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+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 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;
+ 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<DNS_HDR_SIZE) {
+ adns__diag(ads,serv,"received datagram too short for message header (%d)",len);
+ return;
+ }
+ 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_HDR_SIZE);
+
+ flg_ra= f2&0x80;
+
+ if (f1&0x80) {
+ adns__diag(ads,serv,"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);
+ return;
+ }
+ if (!qdcount) {
+ adns__diag(ads,serv,"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",
+ qdcount);
+ return;
+ }
+ for (qu= ads->timew; qu= nqu; qu++) {
+ nqu= qu->next;
+ if (qu->id != id) continue;
+ if (len < qu->querylen) continue;
+ if (memcmp(qu->querymsg+DNSHDRSIZE,dgram+DNSHDRSIZE,qu->querylen-DNSHDRSIZE))
+ continue;
+ break;
+ }
+ anstart= qu->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);
+ return;
+ }
+
+ rcode= (f1&0x0f);
+ 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);
+ return;
+ case rcode_servfail;
+ adns__query_fail(ads,qu,adns_s_serverfailure);
+ return;
+ 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->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 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);
+ }
+ 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)) {
+ 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= 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; }
+ }
+
+ 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
+ if (cbyte+lab
+ if (anstart > dgend) { truncated(ads,qu,f1); return; }
+ }
+ for
+
+ /* Look for CNAMEs in the answer section */
+
+ }
+
+
+ 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);
+
}
+
+ 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