From: Oliver Chen <oliver.chen@nokia-sbell.com>
Date: Mon, 9 Jun 2025 01:54:00 +0000 (+0000)
Subject: Address PR comments of reword and remove rsp payload size check
X-Git-Tag: dnsdist-2.0.0-beta1~36^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3c13e71f31bc328c8498cbb432dac6ab8556bbc4;p=thirdparty%2Fpdns.git

Address PR comments of reword and remove rsp payload size check
---

diff --git a/pdns/dnsdistdist/dnsdist-settings-definitions.yml b/pdns/dnsdistdist/dnsdist-settings-definitions.yml
index 7a60899eee..84858a572b 100644
--- a/pdns/dnsdistdist/dnsdist-settings-definitions.yml
+++ b/pdns/dnsdistdist/dnsdist-settings-definitions.yml
@@ -1939,7 +1939,7 @@ packet_cache:
     - name: "payload_ranks"
       type: "Vec<u16>"
       default: "[]"
-      description: "List of payload size used when hashing the packet. The list will be sorted in ascend order and searched to find a lower bound value for the payload size in the packet. If found then it will be used for packet hashing. Values less than 512 or greater than ``maximum_entry_size`` above will be discarded. This option is to enable cache entry sharing between clients using different payload sizes when needed"
+      description: "List of payload size used when hashing the packet. The list will be sorted in ascending order and searched to find a lower bound value for the payload size in the packet. If found then it will be used for packet hashing. Values less than 512 or greater than ``maximum_entry_size`` above will be discarded. This option is to enable cache entry sharing between clients using different payload sizes when needed"
 
 proxy_protocol:
   description: "Proxy Protocol-related settings"
diff --git a/pdns/dnsdistdist/dnsdist.cc b/pdns/dnsdistdist/dnsdist.cc
index e364a32619..2ff8063213 100644
--- a/pdns/dnsdistdist/dnsdist.cc
+++ b/pdns/dnsdistdist/dnsdist.cc
@@ -639,15 +639,7 @@ void handleResponseSent(const DNSName& qname, const QType& qtype, double udiff,
 
 static void handleResponseTC4UDPClient(uint16_t udpPayloadSize, PacketBuffer& response, DNSResponse& dnsResponse)
 {
-  if (udpPayloadSize == 0) {
-    uint16_t zValue = 0;
-    // NOLINTNEXTLINE(cppcoreguidelines-pro-type-reinterpret-cast)
-    getEDNSUDPPayloadSizeAndZ(reinterpret_cast<const char*>(response.data()), response.size(), &udpPayloadSize, &zValue);
-    if (udpPayloadSize < 512) {
-      udpPayloadSize = 512;
-    }
-  }
-  if (response.size() > udpPayloadSize) {
+  if (udpPayloadSize > 0 && response.size() > udpPayloadSize) {
     vinfolog("Got a response of size %d while the initial UDP payload size was %d, truncating", response.size(), udpPayloadSize);
     truncateTC(dnsResponse.getMutableData(), dnsResponse.getMaximumSize(), dnsResponse.ids.qname.wirelength(), dnsdist::configuration::getCurrentRuntimeConfiguration().d_addEDNSToSelfGeneratedResponses);
     dnsdist::PacketMangling::editDNSHeaderFromPacket(dnsResponse.getMutableData(), [](dnsheader& header) {
diff --git a/pdns/dnsdistdist/docs/reference/config.rst b/pdns/dnsdistdist/docs/reference/config.rst
index c035266963..8adffc1fb6 100644
--- a/pdns/dnsdistdist/docs/reference/config.rst
+++ b/pdns/dnsdistdist/docs/reference/config.rst
@@ -1065,7 +1065,7 @@ See :doc:`../guides/cache` for a how to.
   * ``cookieHashing=false``: bool - If true, EDNS Cookie values will be hashed, resulting in separate entries for different cookies in the packet cache. This is required if the backend is sending answers with EDNS Cookies, otherwise a client might receive an answer with the wrong cookie.
   * ``skipOptions={}``: Extra list of EDNS option codes to skip when hashing the packet (if ``cookieHashing`` above is false, EDNS cookie option number will be added to this list internally).
   * ``maximumEntrySize=4096``: int - The maximum size, in bytes, of a DNS packet that can be inserted into the packet cache. Default is 4096 bytes, which was the fixed size before 1.9.0, and is also a hard limit for UDP responses.
-  * ``payloadRanks={}``: List of payload size used when hashing the packet. The list will be sorted in ascend order and searched to find a lower bound value for the payload size in the packet. If found then it will be used for packet hashing. Values less than 512 or greater than ``maximumEntrySize`` above will be discarded. This option is to enable cache entry sharing between clients using different payload sizes when needed.
+  * ``payloadRanks={}``: List of payload size used when hashing the packet. The list will be sorted in ascending order and searched to find a lower bound value for the payload size in the packet. If found then it will be used for packet hashing. Values less than 512 or greater than ``maximumEntrySize`` above will be discarded. This option is to enable cache entry sharing between clients using different payload sizes when needed.
 
 .. class:: PacketCache
 
diff --git a/regression-tests.dnsdist/test_Caching.py b/regression-tests.dnsdist/test_Caching.py
index 78aa81d231..8483944232 100644
--- a/regression-tests.dnsdist/test_Caching.py
+++ b/regression-tests.dnsdist/test_Caching.py
@@ -544,7 +544,7 @@ class TestCaching(DNSDistTest):
             if len(content) > 0:
                 content = content + ', '
             content = content + (str(i)*50)
-        # pad up to 4096
+        # pad up to 4096 (less 11 for EDNS)
         content = content + 'A'*31
 
         rrset = dns.rrset.from_text(name,