reversed packetcache 'powerdns.com' -> 'moc sndrewop '

diff --git a/pdns/packetcache.cc b/pdns/packetcache.cc
index cd244a58e6dbd659d7b7e8f9cd554c2d8ba9890d..7db48e1faf6bef87da3e484ba3df9dcd62264d24 100644 (file)
--- a/pdns/packetcache.cc
+++ b/pdns/packetcache.cc
@@ -158,7 +158,7 @@ void PacketCache::insert(const string &qname, const QType& qtype, CacheEntryType
   CacheEntry val;
   val.created=time(0);
   val.ttd=val.created+ttl;
-  val.qname=qname;
+  val.qname=pcReverse(qname);
   val.qtype=qtype.getCode();
   val.value=value;
   val.ctype=cet;
@@ -198,60 +198,17 @@ int PacketCache::purge(const string &match)
   WriteLock l(&d_mut);
   int delcount=0;
 
-  /* ok, the suffix delete plan. We want to be able to delete everything that 
-     pertains 'www.powerdns.com' but we also want to be able to delete everything
-     in the powerdns.com zone, so: 'powerdns.com' and '*.powerdns.com'.
-
-     However, we do NOT want to delete 'usepowerdns.com!, nor 'powerdnsiscool.com'
-
-     So, at first shot, store in reverse label order:
-
-     'be.someotherdomain'
-     'com.powerdns'
-     'com.powerdns.images'
-     'com.powerdns.www'
-     'com.powerdnsiscool'
-     'com.usepowerdns.www'
-
-     If we get a request to remove 'everything above powerdns.com', we do a search for 'com.powerdns' which is guaranteed to come first (it is shortest!)
-     Then we delete everything that is either equal to 'com.powerdns' or begins with 'com.powerdns.' This trailing dot saves us 
-     from deleting 'com.powerdnsiscool'.
-
-     We can stop the process once we reach something that doesn't match.
-
-     Ok - fine so far, except it doesn't work! Let's say there *is* no 'com.powerdns' in cache!
-
-     In that case our request doesn't find anything.. now what.
-     lower_bound to the rescue! It finds the place where 'com.powerdns' *would* be.
-     
-     Ok - next step, can we get away with simply reversing the string?
-
-     'moc.sndrewop'
-     'moc.sndrewop.segami'
-     'moc.sndrewop.www'
-     'moc.loocsidnsrewop'
-     'moc.dnsrewopesu.www'
-
-     Ok - next step, can we get away with only reversing the comparison?
-
-     'powerdns.com'
-     'images.powerdns.com'
-     '   www.powerdns.com'
-     'powerdnsiscool.com'
-     'www.userpowerdns.com'
-
-  */
   if(ends_with(match, "$")) {
-    string suffix(match);
-    suffix.resize(suffix.size()-1);
+    string prefix(match);
+    prefix.resize(prefix.size()-1);
+
+    string zone = pcReverse(prefix);
 
-    cmap_t::const_iterator iter = d_map.lower_bound(tie(suffix));
+    cmap_t::const_iterator iter = d_map.lower_bound(tie(zone));
     cmap_t::const_iterator start=iter;
-    string dotsuffix = "."+suffix;
 
     for(; iter != d_map.end(); ++iter) {
-      if(!pdns_iequals(iter->qname, suffix) && !iends_with(iter->qname, dotsuffix)) {
-        //        cerr<<"Stopping!"<<endl;
+      if(!iter->qname.compare(0, zone.size(), zone)) {
         break;
       }
       delcount++;
@@ -259,8 +216,10 @@ int PacketCache::purge(const string &match)
     d_map.erase(start, iter);
   }
   else {
-    delcount=d_map.count(tie(match));
-    pair<cmap_t::iterator, cmap_t::iterator> range = d_map.equal_range(tie(match));
+    string qname = pcReverse(match);
+
+    delcount=d_map.count(tie(qname));
+    pair<cmap_t::iterator, cmap_t::iterator> range = d_map.equal_range(tie(qname));
     d_map.erase(range.first, range.second);
   }
   *d_statnumentries=d_map.size();
@@ -292,7 +251,8 @@ bool PacketCache::getEntryLocked(const string &qname, const QType& qtype, CacheE
 {
   uint16_t qt = qtype.getCode();
   //cerr<<"Lookup for maxReplyLen: "<<maxReplyLen<<endl;
-  cmap_t::const_iterator i=d_map.find(tie(qname, qt, cet, zoneID, meritsRecursion, maxReplyLen, dnssecOK, hasEDNS, *age));
+  string pcqname = pcReverse(qname);
+  cmap_t::const_iterator i=d_map.find(tie(pcqname, qt, cet, zoneID, meritsRecursion, maxReplyLen, dnssecOK, hasEDNS, *age));
   time_t now=time(0);
   bool ret=(i!=d_map.end() && i->ttd > now);
   if(ret) {
@@ -304,6 +264,14 @@ bool PacketCache::getEntryLocked(const string &qname, const QType& qtype, CacheE
   return ret;
 }
 
+
+string PacketCache::pcReverse(const string &content)
+{
+  string tmp = string(content.rbegin(), content.rend());
+  return toLower(boost::replace_all_copy(tmp, ".", " "))+" ";
+}
+
+
 map<char,int> PacketCache::getCounts()
 {
   ReadLock l(&d_mut);

diff --git a/pdns/packetcache.hh b/pdns/packetcache.hh
index a447a8813cf74f440c47811b57274bc40a83b021..2121b44d574b3272674fc445e6e7ba30334d7c63 100644 (file)
--- a/pdns/packetcache.hh
+++ b/pdns/packetcache.hh
@@ -47,24 +47,6 @@ using namespace ::boost::multi_index;
     first marks and then sweeps, a second lock is present to prevent simultaneous inserts and deletes.
 */
 
-struct CIBackwardsStringCompare: public std::binary_function<string, string, bool>  
-{
-  bool operator()(const string& str_a, const string& str_b) const
-  {
-    string::const_reverse_iterator ra, rb;
-    char a=0, b=0;
-    for(ra = str_a.rbegin(), rb = str_b.rbegin();
-        ra < str_a.rend() && rb < str_b.rend() && (a=dns_tolower(*ra)) == (b=dns_tolower(*rb));
-        ra++, rb++);
-    
-    if (ra < str_a.rend() && rb==str_b.rend()) { a=*(ra++); b=0; return false; } // we are at the beginning of b -> b smaller
-    if (rb < str_b.rend() && ra==str_a.rend()) { b=*(rb++); a=0; return true; } // we are at the beginning of a -> a smaller
-    // if BOTH are at their ends, a and b will be equal, and we should return false, which we will
-    return a < b;
-  }
-};
-
-
 class PacketCache : public boost::noncopyable
 {
 public:
@@ -90,6 +72,7 @@ public:
 private:
   bool getEntryLocked(const string &content, const QType& qtype, CacheEntryType cet, string& entry, int zoneID=-1,
     bool meritsRecursion=false, unsigned int maxReplyLen=512, bool dnssecOk=false, bool hasEDNS=false, unsigned int *age=0);
+  string pcReverse(const string &content);
   struct CacheEntry
   {
     CacheEntry() { qtype = ctype = 0; zoneID = -1; meritsRecursion=false; dnssecOk=false; hasEDNS=false;}
@@ -124,7 +107,7 @@ private:
                         member<CacheEntry,bool, &CacheEntry::dnssecOk>,
                         member<CacheEntry,bool, &CacheEntry::hasEDNS>
                         >,
-                        composite_key_compare<CIBackwardsStringCompare, std::less<uint16_t>, std::less<uint16_t>, std::less<int>, std::less<bool>, 
+                        composite_key_compare<std::less<string>, std::less<uint16_t>, std::less<uint16_t>, std::less<int>, std::less<bool>, 
                           std::less<unsigned int>, std::less<bool>, std::less<bool> >
                             >,
                            sequenced<>