From b741c385597d43d38c3858c816732ddc0ad1eab1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henryk=20Pl=C3=B6tz?= <henryk@ploetzli.ch>
Date: Fri, 3 Oct 2014 20:12:35 +0200
Subject: Apply 0004-dnscache.c-allow-a-maximum-of-20-concurrent-outgoing.diff
 SHA1 138118548db85af9ff3193fb58e923c6ca877956, contained in
 djbdns_1.05-8ubuntu1.diff.gz Source was
 http://archive.ubuntu.com/ubuntu/pool/universe/d/djbdns/djbdns_1.05-8ubuntu1.diff.gz,
 SHA1 0813f9370548f8699d442207bdd36ae9ef567b15

---
 dnscache.c | 15 +++++++++++++++
 log.c      |  6 ++++++
 2 files changed, 21 insertions(+)

diff --git a/dnscache.c b/dnscache.c
index abcba69..2366ecc 100644
--- a/dnscache.c
+++ b/dnscache.c
@@ -72,11 +72,15 @@ static struct udpclient {
 } u[MAXUDP];
 int uactive = 0;
 
+#define MAXSOA 20
+int soaactive = 0;
+
 void u_drop(int j)
 {
   if (!u[j].active) return;
   log_querydrop(&u[j].active);
   u[j].active = 0; --uactive;
+  if (byte_equal(u[j].q.type,2,DNS_T_SOA)) --soaactive;
 }
 
 void u_respond(int j)
@@ -87,6 +91,7 @@ void u_respond(int j)
   socket_send6(udp53,response,response_len,u[j].ip,u[j].port,u[j].scope_id);
   log_querydone(&u[j].active,response_len);
   u[j].active = 0; --uactive;
+  if (byte_equal(u[j].q.type,2,DNS_T_SOA)) --soaactive;
 }
 
 void u_new(void)
@@ -125,6 +130,16 @@ void u_new(void)
 
   x->active = ++numqueries; ++uactive;
   log_query(&x->active,x->ip,x->port,x->id,q,qtype);
+
+  if (byte_equal(qtype,2,DNS_T_SOA)) {
+    if (soaactive >= MAXSOA) {
+      log_querydropmaxsoa(&x->active);
+      x->active = 0; --uactive;
+      return;
+    }
+    ++soaactive;
+  }
+
   switch(query_start(&x->q,q,qtype,qclass,myipoutgoing,interface)) {
     case -1:
       u_drop(j);
diff --git a/log.c b/log.c
index df465e2..a651607 100644
--- a/log.c
+++ b/log.c
@@ -118,6 +118,12 @@ void log_querydrop(uint64 *qnum)
   line();
 }
 
+void log_querydropmaxsoa(uint64 *qnum)
+{
+  string("drop "); number(*qnum); space(); string("maxsoa");
+  line();
+}
+
 void log_tcpopen(const char client[16],unsigned int port)
 {
   string("tcpopen ");
-- 
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