From: Jeremy Clerc <j.clerc@criteo.com>
Date: Fri, 22 Nov 2019 07:31:16 +0000 (+0100)
Subject: geoipbackend: stop looking after first weighted match
X-Git-Tag: rec-4.4.0-beta1~37^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2f2e58af3d6246276056376de0809c1b3fb100e0;p=thirdparty%2Fpdns.git

geoipbackend: stop looking after first weighted match

In the case of weighted round robin, we will give back only one
GeoIPDNSResourceRecord, so once we found it, there is no point to
keep looking except inducing a performance penalty.

This commit ensures we stop looking after we found our first weighted
match.
---

diff --git a/modules/geoipbackend/geoipbackend.cc b/modules/geoipbackend/geoipbackend.cc
index b56d16f5d9..de4fc00286 100644
--- a/modules/geoipbackend/geoipbackend.cc
+++ b/modules/geoipbackend/geoipbackend.cc
@@ -314,11 +314,13 @@ GeoIPBackend::~GeoIPBackend() {
 bool GeoIPBackend::lookup_static(const GeoIPDomain &dom, const DNSName &search, const QType &qtype, const DNSName& qdomain, const Netmask& addr, GeoIPNetmask &gl) {
   const auto& i = dom.records.find(search);
   map<uint16_t,int> cumul_probabilities;
+  map<uint16_t,bool> weighted_match;
   int probability_rnd = 1+(dns_random(1000)); // setting probability=0 means it never is used
 
   if (i != dom.records.end()) { // return static value
     for(const auto& rr : i->second) {
-      if (qtype != QType::ANY && rr.qtype != qtype) continue;
+      if ((qtype != QType::ANY && rr.qtype != qtype) || weighted_match[rr.qtype.getCode()])
+        continue;
 
       if (rr.has_weight) {
         gl.netmask = (addr.isIpv6()?128:32);
@@ -332,6 +334,10 @@ bool GeoIPBackend::lookup_static(const GeoIPDomain &dom, const DNSName &search,
       d_result.push_back(rr);
       d_result.back().content = content;
       d_result.back().qname = qdomain;
+      // If we are weighted we only return one resource and we found a matching resource,
+      // so no need to check the other ones.
+      if (rr.has_weight)
+        weighted_match[rr.qtype.getCode()] = true;
     }
     // ensure we get most strict netmask
     for(DNSResourceRecord& rr: d_result) {