From a7c46702841348785f22e550636cb66d534be087 Mon Sep 17 00:00:00 2001
From: bert hubert <bert.hubert@netherlabs.nl>
Date: Sun, 15 Apr 2018 16:29:17 +0200
Subject: [PATCH] remove safearray, dnsmessagereader can now parse "any" length

---
 tdns/dnsmessages.cc | 25 +++++++++++++------------
 tdns/dnsmessages.hh | 27 ++++++++++++++++++++++++---
 tdns/safearray.hh   | 38 --------------------------------------
 3 files changed, 37 insertions(+), 53 deletions(-)
 delete mode 100644 tdns/safearray.hh

diff --git a/tdns/dnsmessages.cc b/tdns/dnsmessages.cc
index 65f778c..4779c48 100644
--- a/tdns/dnsmessages.cc
+++ b/tdns/dnsmessages.cc
@@ -8,19 +8,20 @@ DNSMessageReader::DNSMessageReader(const char* in, uint16_t size)
   if(size < sizeof(dnsheader))
     throw std::runtime_error("DNS message too small");
   memcpy(&dh, in, sizeof(dh));
-  auto rest = size-sizeof(dh);
-  memcpy(&payload.payload.at(rest)-rest, in+sizeof(dh), rest);
+  payload.reserve(size-12);
+  payload.insert(payload.begin(), (const unsigned char*)in + 12, (const unsigned char*)in + size);
+
   d_qname = getName();
-  d_qtype = (DNSType) payload.getUInt16();
-  d_qclass = (DNSClass) payload.getUInt16();
+  d_qtype = (DNSType) getUInt16();
+  d_qclass = (DNSClass) getUInt16();
   if(dh.arcount) {
-    if(payload.getUInt8() == 0 && payload.getUInt16() == (uint16_t)DNSType::OPT) {
-      d_bufsize=payload.getUInt16();
-      payload.getUInt8(); // extended RCODE
-      d_ednsVersion = payload.getUInt8(); 
-      auto flags = payload.getUInt8();
+    if(getUInt8() == 0 && getUInt16() == (uint16_t)DNSType::OPT) {
+      d_bufsize=getUInt16();
+      getUInt8(); // extended RCODE
+      d_ednsVersion = getUInt8(); 
+      auto flags = getUInt8();
       d_doBit = flags & 0x80;
-      payload.getUInt8(); payload.getUInt16(); // ignore rest
+      getUInt8(); getUInt16(); // ignore rest
       cout<<"   There was an EDNS section, size supported: "<< d_bufsize<<endl;
       d_haveEDNS = true;
     }
@@ -31,12 +32,12 @@ DNSName DNSMessageReader::getName()
 {
   DNSName name;
   for(;;) {
-    uint8_t labellen=payload.getUInt8();
+    uint8_t labellen=getUInt8();
     if(labellen > 63)
       throw std::runtime_error("Got a compressed label");
     if(!labellen) // end of DNSName
       break;
-    DNSLabel label = payload.getBlob(labellen);
+    DNSLabel label = getBlob(labellen);
     name.push_back(label);
   }
   return name;
diff --git a/tdns/dnsmessages.hh b/tdns/dnsmessages.hh
index 763451f..f539336 100644
--- a/tdns/dnsmessages.hh
+++ b/tdns/dnsmessages.hh
@@ -1,8 +1,8 @@
 #pragma once
 #include "dns.hh"
-#include "safearray.hh"
 #include "dns-storage.hh"
 #include "record-types.hh"
+#include <arpa/inet.h>
 #include <vector>
 
 class DNSMessageReader
@@ -11,13 +11,34 @@ public:
   DNSMessageReader(const char* input, uint16_t length);
   DNSMessageReader(const std::string& str) : DNSMessageReader(str.c_str(), str.size()) {}
   struct dnsheader dh=dnsheader{};
-  SafeArray<500> payload;
-
+  std::vector<uint8_t> payload;
+  uint16_t payloadpos{0};
+  
   void getQuestion(DNSName& name, DNSType& type) const;
   bool getEDNS(uint16_t* newsize, bool* doBit) const;
   uint8_t d_ednsVersion{0};
 private:
   DNSName getName();
+  uint8_t getUInt8()
+  {
+    return payload.at(payloadpos++);
+  }
+  
+  uint16_t getUInt16()
+  {
+    uint16_t ret;
+    memcpy(&ret, &payload.at(payloadpos+1)-1, 2);
+    payloadpos+=2;
+    return htons(ret);
+  }
+  
+  std::string getBlob(int size)
+  {
+    std::string ret(&payload.at(payloadpos), &payload.at(payloadpos+size));
+    payloadpos += size;
+    return ret;
+  }
+
   DNSName d_qname;
   DNSType d_qtype;
   DNSClass d_qclass;
diff --git a/tdns/safearray.hh b/tdns/safearray.hh
deleted file mode 100644
index fe13da0..0000000
--- a/tdns/safearray.hh
+++ /dev/null
@@ -1,38 +0,0 @@
-#pragma once
-#include <string>
-#include <cstdint>
-#include <array>
-#include <arpa/inet.h>
-#include <string.h>
-
-template<int N>
-struct SafeArray
-{
-  std::array<uint8_t, N> payload;
-  uint16_t payloadpos{0}, payloadsize{0};
-
-  void rewind()
-  {
-    payloadpos = 0;
-  }
-
-  uint8_t getUInt8()
-  {
-    return payload.at(payloadpos++);
-  }
-  
-  uint16_t getUInt16()
-  {
-    uint16_t ret;
-    memcpy(&ret, &payload.at(payloadpos+2)-2, 2);
-    payloadpos+=2;
-    return htons(ret);
-  }
-  
-  std::string getBlob(int size)
-  {
-    std::string ret(&payload.at(payloadpos), &payload.at(payloadpos+size));
-    payloadpos += size;
-    return ret;
-  }
-};