From 03c05963ccad3bdae5f4da9280f2432084f866a6 Mon Sep 17 00:00:00 2001
From: Charles-Henri Bruyand <charles-henri.bruyand@open-xchange.com>
Date: Fri, 26 Oct 2018 17:21:28 +0200
Subject: [PATCH] dnsdist: add setConsoleOutputMaxMsgSize function to tune
 console output message maximum size

---
 pdns/dnsdist-console.cc                    | 29 ++++++++++++++++++++++
 pdns/dnsdist-console.hh                    |  1 +
 pdns/dnsdist-lua.cc                        |  4 +++
 pdns/dnsdist-tcp.cc                        | 27 --------------------
 pdns/dnsdistdist/docs/reference/config.rst |  8 ++++++
 5 files changed, 42 insertions(+), 27 deletions(-)

diff --git a/pdns/dnsdist-console.cc b/pdns/dnsdist-console.cc
index 53210fe85..d0195c9ec 100644
--- a/pdns/dnsdist-console.cc
+++ b/pdns/dnsdist-console.cc
@@ -44,6 +44,7 @@ vector<pair<struct timeval, string> > g_confDelta;
 std::string g_consoleKey;
 bool g_logConsoleConnections{true};
 bool g_consoleEnabled{false};
+uint32_t g_consoleOutputMsgMaxSize{10000000};
 
 // MUST BE CALLED UNDER A LOCK - right now the LuaLock
 static void feedConfigDelta(const std::string& line)
@@ -412,6 +413,7 @@ const std::vector<ConsoleKeyword> g_consoleKeywords{
   { "setAPIWritable", true, "bool, dir", "allow modifications via the API. if `dir` is set, it must be a valid directory where the configuration files will be written by the API" },
   { "setConsoleACL", true, "{netmask, netmask}", "replace the console ACL set with these netmasks" },
   { "setConsoleConnectionsLogging", true, "enabled", "whether to log the opening and closing of console connections" },
+  { "setConsoleOutputMaxMsgSize", true, "messageSize", "set console message maximum size in bytes, default is 10 MB" },
   { "setDNSSECPool", true, "pool name", "move queries requesting DNSSEC processing to this pool" },
   { "setDynBlocksAction", true, "action", "set which action is performed when a query is blocked. Only DNSAction.Drop (the default) and DNSAction.Refused are supported" },
   { "setECSOverride", true, "bool", "whether to override an existing EDNS Client Subnet value in the query" },
@@ -700,3 +702,30 @@ catch(const std::exception& e)
   close(fd);
   errlog("Control connection died: %s", e.what());
 }
+
+bool getMsgLen32(int fd, uint32_t* len)
+try
+{
+  uint32_t raw;
+  size_t ret = readn2(fd, &raw, sizeof raw);
+  if(ret != sizeof raw)
+    return false;
+  *len = ntohl(raw);
+  if(*len > g_consoleOutputMsgMaxSize)
+    return false;
+  return true;
+}
+catch(...) {
+   return false;
+}
+
+bool putMsgLen32(int fd, uint32_t len)
+try
+{
+  uint32_t raw = htonl(len);
+  size_t ret = writen2(fd, &raw, sizeof raw);
+  return ret==sizeof raw;
+}
+catch(...) {
+  return false;
+}
diff --git a/pdns/dnsdist-console.hh b/pdns/dnsdist-console.hh
index 7de8b6845..1c3bb6e2f 100644
--- a/pdns/dnsdist-console.hh
+++ b/pdns/dnsdist-console.hh
@@ -43,6 +43,7 @@ extern const std::vector<ConsoleKeyword> g_consoleKeywords;
 extern std::string g_consoleKey; // in theory needs locking
 extern bool g_logConsoleConnections;
 extern bool g_consoleEnabled;
+extern uint32_t g_consoleOutputMsgMaxSize;
 
 void doClient(ComboAddress server, const std::string& command);
 void doConsole();
diff --git a/pdns/dnsdist-lua.cc b/pdns/dnsdist-lua.cc
index 00bb21651..40abb4bce 100644
--- a/pdns/dnsdist-lua.cc
+++ b/pdns/dnsdist-lua.cc
@@ -1469,6 +1469,10 @@ void setupLuaConfig(bool client)
       g_logConsoleConnections = enabled;
     });
 
+  g_lua.writeFunction("setConsoleOutputMaxMsgSize", [](uint32_t size) {
+      g_consoleOutputMsgMaxSize = size;
+    });
+
   g_lua.writeFunction("setUDPMultipleMessagesVectorSize", [](size_t vSize) {
       if (g_configurationDone) {
         errlog("setUDPMultipleMessagesVectorSize() cannot be used at runtime!");
diff --git a/pdns/dnsdist-tcp.cc b/pdns/dnsdist-tcp.cc
index 9eba86191..b918c7968 100644
--- a/pdns/dnsdist-tcp.cc
+++ b/pdns/dnsdist-tcp.cc
@@ -776,30 +776,3 @@ void* tcpAcceptorThread(void* p)
 
   return 0;
 }
-
-bool getMsgLen32(int fd, uint32_t* len)
-try
-{
-  uint32_t raw;
-  size_t ret = readn2(fd, &raw, sizeof raw);
-  if(ret != sizeof raw)
-    return false;
-  *len = ntohl(raw);
-  if(*len > 10000000) // arbitrary 10MB limit
-    return false;
-  return true;
-}
-catch(...) {
-   return false;
-}
-
-bool putMsgLen32(int fd, uint32_t len)
-try
-{
-  uint32_t raw = htonl(len);
-  size_t ret = writen2(fd, &raw, sizeof raw);
-  return ret==sizeof raw;
-}
-catch(...) {
-  return false;
-}
diff --git a/pdns/dnsdistdist/docs/reference/config.rst b/pdns/dnsdistdist/docs/reference/config.rst
index 90da2e703..345a25541 100644
--- a/pdns/dnsdistdist/docs/reference/config.rst
+++ b/pdns/dnsdistdist/docs/reference/config.rst
@@ -203,6 +203,14 @@ Control Socket, Console and Webserver
 
   Test the crypto code, will report errors when something is not ok.
 
+.. function:: setConsoleOutputMaxMsgSize(size)
+
+  .. versionadded:: 1.3.3
+
+  Set the maximum size in bytes of a single console message, default set to 10 MB.
+
+  :param int size: The new maximum size.
+
 Webserver
 ~~~~~~~~~
 
-- 
2.40.0