--- /dev/null
+/*
+ * PowerDNS backend module for MyDNS style databases
+ * Author: Jonathan Oddy (Hostway UK) <jonathan@woaf.net>
+ *
+ * The schema used by MyDNS isn't suitable for retrieving results with a single
+ * query. This means that existing PowerDNS backends are unable to make use of
+ * the schema without lame hackery (or awful performance.) This module does
+ * the nasty lookup logic required to make use of the schema, and should be as
+ * tollerent as MyDNS when it comes to things being fully qualified or not.
+ *
+ * A known "bug" is that AXFRs will fail if your rr table contains invalid
+ * junk. I'm not sure this is really a bug, if you've decided to put free-form
+ * text in your data for an A record you have bigger issues.
+ *
+ * I'd advise avoiding the MyDNS schema if at all possible as the query count
+ * for even simple lookups is daft. It's quite trivial to craft a request
+ * that'll require 128 database queries to answer with a servfail!
+ *
+ */
+
+#include <string>
+#include <map>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sstream>
+
+using namespace std;
+
+#include <pdns/dns.hh>
+#include <pdns/dnsbackend.hh>
+#include "mydnsbackend.hh"
+#include <pdns/dnspacket.hh>
+#include <pdns/ueberbackend.hh>
+#include <pdns/ahuexception.hh>
+#include <pdns/logger.hh>
+#include <pdns/arguments.hh>
+
+#include <modules/gmysqlbackend/smysql.hh>
+
+static string backendName="[MyDNSbackend]";
+
+MyDNSBackend::MyDNSBackend(const string &suffix) {
+ setArgPrefix("mydns"+suffix);
+
+ try {
+ d_db = new SMySQL(getArg("dbname"),
+ getArg("host"),
+ getArgAsNum("port"),
+ getArg("socket"),
+ getArg("user"),
+ getArg("password"));
+
+ }
+ catch(SSqlException &e) {
+ L<<Logger::Error<<backendName<<" Connection failed: "<<e.txtReason()<<endl;
+ throw AhuException(backendName+"Unable to launch connection: "+e.txtReason());
+ }
+
+ d_rrtable=getArg("rr-table");
+ d_soatable=getArg("soa-table");
+ d_rrwhere=(mustDo("rr-active")?"active = 1 and ":"")+getArg("rr-where");
+ d_soawhere=(mustDo("soa-active")?"active = 1 and ":"")+getArg("soa-where");
+
+ L<<Logger::Warning<<backendName<<" Connection succesful"<<endl;
+}
+
+MyDNSBackend::~MyDNSBackend() {
+ if (d_db)
+ delete(d_db);
+}
+
+
+void MyDNSBackend::Query(const string &query) {
+ try {
+ d_db->doQuery(query);
+ } catch (SSqlException &e) {
+ throw AhuException("Query failed: "+e.txtReason());
+ }
+}
+
+bool MyDNSBackend::list(const string &target, int zoneId) {
+ string query;
+ string sname;
+ SSql::row_t rrow;
+
+ d_db->setLog(::arg().mustDo("query-logging"));
+
+ query = "select origin, minimum from "+d_soatable+" where id = ";
+ ostringstream o;
+ o<<zoneId;
+ query+=o.str();
+ query+= " and "+d_soawhere;
+
+ this->Query(query);
+
+ if(!d_db->getRow(rrow)) {
+ // No such zone
+ return false;
+ }
+
+ d_origin = rrow[0];
+ if (d_origin[d_origin.length()-1] == '.')
+ d_origin.erase(d_origin.length()-1);
+ d_minimum = atol(rrow[1].c_str());
+
+ while (d_db->getRow(rrow)) {
+ L<<Logger::Warning<<backendName<<" Found more than one matching origin for zone ID: "+zoneId<<endl;
+ };
+
+ query = "select type, data, aux, ttl, zone, name from "+d_rrtable+" where zone = ";
+ query+=o.str();
+ query += " and "+d_rrwhere;
+
+ this->Query(query);
+
+ d_qname = "";
+ return true;
+
+}
+
+bool MyDNSBackend::getSOA(const string& name, SOAData& soadata, DNSPacket*) {
+ string query;
+ SSql::row_t rrow;
+
+ d_db->setLog(::arg().mustDo("query-logging"));
+
+ if (name.empty())
+ return false;
+
+ query = "select id, mbox, serial, ns, refresh, retry, expire, minimum, ttl from "+d_soatable+" where origin = '";
+
+ if (name.find_first_of("'\\")!=string::npos)
+ query+=d_db->escape(name);
+ else
+ query+=name;
+
+ query+=".' and "+d_soawhere;
+
+ this->Query(query);
+
+ if(!(d_db->getRow(rrow))) {
+ return false;
+ }
+
+ soadata.domain_id = atol(rrow[0].c_str());
+ soadata.hostmaster = rrow[1];
+ soadata.serial = atol(rrow[2].c_str());
+ soadata.nameserver = rrow[3];
+ soadata.refresh = atol(rrow[4].c_str());
+ soadata.retry = atol(rrow[5].c_str());
+ soadata.expire = atol(rrow[6].c_str());
+ soadata.default_ttl = atol(rrow[7].c_str());
+ soadata.ttl = atol(rrow[8].c_str());
+ if (soadata.ttl < soadata.default_ttl) {
+ soadata.ttl = soadata.default_ttl;
+ }
+ soadata.db = this;
+
+ while (d_db->getRow(rrow)) {
+ L<<Logger::Warning<<backendName<<" Found more than one matching zone for: "+name<<endl;
+ };
+
+ return true;
+}
+
+void MyDNSBackend::lookup(const QType &qtype, const string &qname, DNSPacket *p, int zoneId) {
+ string query;
+ string sname;
+ SSql::row_t rrow;
+ bool found = false;
+
+ d_origin = "";
+
+ d_db->setLog(::arg().mustDo("query-logging"));
+
+ if (qname.empty())
+ return;
+
+ // Escape the name, after this point we only want to use it in queries
+ if (qname.find_first_of("'\\")!=string::npos)
+ sname=d_db->escape(qname);
+ else
+ sname = qname;
+ sname += ".";
+
+ if (zoneId < 0) {
+ // First off we need to work out what zone we're working with
+ // MyDNS records aren't always fully qualified, so we need to work out the zone ID.
+
+ size_t pos;
+ string sdom;
+
+ pos = 0;
+ sdom = sname;
+ while (!sdom.empty() && pos != string::npos) {
+ query = "select id, origin, minimum from "+d_soatable+" where origin = '"+sdom+"' and "+d_soawhere;
+
+ this->Query(query);
+ if(d_db->getRow(rrow)) {
+ zoneId = atol(rrow[0].c_str());
+ d_origin = rrow[1];
+ if (d_origin[d_origin.length()-1] == '.')
+ d_origin.erase(d_origin.length()-1);
+ d_minimum = atol(rrow[2].c_str());
+ found = true;
+ break;
+ }
+
+ pos = sname.find_first_of(".",pos+1);
+ sdom = sname.substr(pos+1);
+ }
+
+ } else {
+ query = "select origin, minimum from "+d_soatable+" where id = ";
+ ostringstream o;
+ o<<zoneId;
+ query+=o.str();
+ query+= " and "+d_soawhere;
+
+ this->Query(query);
+
+ if(!d_db->getRow(rrow)) {
+ throw AhuException("lookup() passed zoneId = "+o.str()+" but no such zone!");
+ }
+
+ found = true;
+ d_origin = rrow[0];
+ if (d_origin[d_origin.length()-1] == '.')
+ d_origin.erase(d_origin.length()-1);
+ d_minimum = atol(rrow[1].c_str());
+ }
+
+
+ if (found) {
+ while (d_db->getRow(rrow)) {
+ L<<Logger::Warning<<backendName<<" Found more than one matching zone for: "+d_origin<<endl;
+ };
+ // We found the zoneId, so we can work out how to find our rr
+ string host;
+
+ // The host part of the query is the name less the origin
+ if (qname.length() == d_origin.length())
+ host = "";
+ else
+ host = qname.substr(0, (qname.length() - d_origin.length())-1);
+
+ if (host.find_first_of("'\\")!=string::npos)
+ host=d_db->escape(host);
+
+ query = "select type, data, aux, ttl, zone from "+d_rrtable+" where zone = ";
+ ostringstream o;
+ o<<zoneId;
+ query+=o.str();
+ query += " and (name = '"+host+"' or name = '"+sname+"')";
+
+ if(qtype.getCode()!=255) { // ANY
+ query+=" and type='";
+ query+=qtype.getName();
+ query+="'";
+ }
+ query += " and "+d_rrwhere+" order by type,aux,data";
+
+ this->Query(query);
+
+ d_qname = qname;
+ }
+
+}
+
+bool MyDNSBackend::get(DNSResourceRecord &rr) {
+ if (d_origin.empty()) {
+ // This happens if lookup() couldn't find the zone
+ return false;
+ }
+
+ SSql::row_t rrow;
+
+ if(!d_db->getRow(rrow)) {
+ return false;
+ }
+
+ rr.qtype=rrow[0];
+ rr.content = rrow[1];
+
+ if(!d_qname.empty()) {
+ // use this to distinguish between select with 'name' field (list()) and one without
+ rr.qname=d_qname;
+ } else {
+ rr.qname=rrow[5];
+ if (rr.qname[rr.qname.length()-1] == '.') {
+ rr.qname.erase(rr.qname.length()-1); // Fully qualified, nuke the last .
+ } else {
+ if (!rr.qname.empty())
+ rr.qname += ".";
+ rr.qname += d_origin; // Not fully qualified
+ }
+ }
+
+ if (rr.qtype == "NS" || rr.qtype == "MX" || rr.qtype == "CNAME" || rr.qtype == "PTR") {
+ if (rr.content[rr.content.length()-1] == '.') {
+ rr.content.erase(rr.content.length()-1); // Fully qualified, nuke the last .
+ } else {
+ if (!rr.content.empty())
+ rr.content += ".";
+ rr.content += d_origin;
+ }
+ }
+
+ rr.priority = atol(rrow[2].c_str());
+ rr.ttl = atol(rrow[3].c_str());
+ if (rr.ttl < d_minimum)
+ rr.ttl = d_minimum;
+ rr.domain_id=atol(rrow[4].c_str());
+
+
+ rr.last_modified=0;
+
+ return true;
+
+}
+
+class MyDNSFactory : public BackendFactory {
+
+public:
+ MyDNSFactory() : BackendFactory("mydns") {}
+
+ void declareArguments(const string &suffix = "") {
+ declare(suffix,"dbname","Pdns backend database name to connect to","mydns");
+ declare(suffix,"user","Pdns backend user to connect as","powerdns");
+ declare(suffix,"host","Pdns backend host to connect to","");
+ declare(suffix,"port","Pdns backend host to connect to","");
+ declare(suffix,"password","Pdns backend password to connect with","");
+ declare(suffix,"socket","Pdns backend socket to connect to","");
+ declare(suffix,"rr-table","Name of RR table to use","rr");
+ declare(suffix,"soa-table","Name of SOA table to use","soa");
+ declare(suffix,"soa-where","Additional WHERE clause for SOA","1 = 1");
+ declare(suffix,"rr-where","Additional WHERE clause for RR","1 = 1");
+ declare(suffix,"soa-active","Use the active column in the SOA table","yes");
+ declare(suffix,"rr-active","Use the active column in the RR table","yes");
+ }
+
+ MyDNSBackend *make(const string &suffix = "") {
+ return new MyDNSBackend(suffix);
+ }
+
+};
+
+class MyDNSLoader {
+
+public:
+ MyDNSLoader() {
+ BackendMakers().report(new MyDNSFactory());
+ L<<Logger::Info<<backendName<<" This is the MyDNSBackend ("__DATE__", "__TIME__") reporting"<<endl;
+ }
+};
+
+static MyDNSLoader mydnsloader;
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