File 12824.patch of Package powerdns-dnsdist

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File 12824.patch of Package powerdns-dnsdist (Revision b66c5f935839563d14e329e46de09a3c)

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From fcb6534d7525ee01ce293cedca9ddc35a5852fa8 Mon Sep 17 00:00:00 2001
From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Mon, 15 May 2023 14:10:55 +0200
Subject: [PATCH 1/2] dnsdist: Stop setting SO_REUSEADDR on outgoing UDP client
 sockets

`SO_REUSEADDR` is useful on TCP server sockets to allow binding quickly
after restarting the process without waiting `TIME_WAIT` seconds, or
to allow some port reuse on BSD. It also allows reusing a port more
quickly for TCP client sockets.
For UDP sockets, however, Linux allows two sockets to be bound to the
same address and port, and will distribute all packets to the most
recent socket, which is very unexpected, to say the least.

(cherry picked from commit b33f09f1989e938c503142a38c556df94254443a)
---
 pdns/dnsdistdist/dnsdist-backend.cc      | 1 -
 pdns/dnsdistdist/dnsdist-healthchecks.cc | 4 +++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/pdns/dnsdistdist/dnsdist-backend.cc b/pdns/dnsdistdist/dnsdist-backend.cc
index 9113183c83f..cfa6e5c7b65 100644
--- a/pdns/dnsdistdist/dnsdist-backend.cc
+++ b/pdns/dnsdistdist/dnsdist-backend.cc
@@ -72,7 +72,6 @@ bool DownstreamState::reconnect()
 #endif
 
     if (!IsAnyAddress(d_config.sourceAddr)) {
-      SSetsockopt(fd, SOL_SOCKET, SO_REUSEADDR, 1);
 #ifdef IP_BIND_ADDRESS_NO_PORT
       if (d_config.ipBindAddrNoPort) {
         SSetsockopt(fd, SOL_IP, IP_BIND_ADDRESS_NO_PORT, 1);
diff --git a/pdns/dnsdistdist/dnsdist-healthchecks.cc b/pdns/dnsdistdist/dnsdist-healthchecks.cc
index 4a520522762..fc831e6481e 100644
--- a/pdns/dnsdistdist/dnsdist-healthchecks.cc
+++ b/pdns/dnsdistdist/dnsdist-healthchecks.cc
@@ -319,7 +319,9 @@ bool queueHealthCheck(std::unique_ptr<FDMultiplexer>& mplexer, const std::shared
 #endif
 
     if (!IsAnyAddress(ds->d_config.sourceAddr)) {
-      sock.setReuseAddr();
+      if (ds->doHealthcheckOverTCP()) {
+        sock.setReuseAddr();
+      }
 #ifdef IP_BIND_ADDRESS_NO_PORT
       if (ds->d_config.ipBindAddrNoPort) {
         SSetsockopt(sock.getHandle(), SOL_IP, IP_BIND_ADDRESS_NO_PORT, 1);

From 2d013627bc15a919f80ff193593813c8a7587a57 Mon Sep 17 00:00:00 2001
From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Mon, 15 May 2023 15:32:27 +0200
Subject: [PATCH 2/2] dnsdist: Really disable REUSEADDR on outgoing UDP client
 sockets

It turns out that our `Socket::bind()` will _helpfully_ enable this
by default.

(cherry picked from commit 20f67fee9447069d4586a41254468ac060b2d65e)
---
 pdns/dnsdistdist/dnsdist-healthchecks.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pdns/dnsdistdist/dnsdist-healthchecks.cc b/pdns/dnsdistdist/dnsdist-healthchecks.cc
index fc831e6481e..ab147cb1501 100644
--- a/pdns/dnsdistdist/dnsdist-healthchecks.cc
+++ b/pdns/dnsdistdist/dnsdist-healthchecks.cc
@@ -327,7 +327,7 @@ bool queueHealthCheck(std::unique_ptr<FDMultiplexer>& mplexer, const std::shared
         SSetsockopt(sock.getHandle(), SOL_IP, IP_BIND_ADDRESS_NO_PORT, 1);
       }
 #endif
-      sock.bind(ds->d_config.sourceAddr);
+      sock.bind(ds->d_config.sourceAddr, false);
     }
 
     auto data = std::make_shared<HealthCheckData>(*mplexer, ds, std::move(checkName), checkType, checkClass, queryID);

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File 12824.patch of Package powerdns-dnsdist (Revision b66c5f935839563d14e329e46de09a3c)

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