From 0d676dc9b9030a7d06a57ec953c8b56ad1bd8978 Mon Sep 17 00:00:00 2001
From: Wiebe Cazemier <wiebe@halfgaar.net>
Date: Wed, 9 Dec 2020 11:07:29 +0100
Subject: [PATCH] Connect handling, mostly

---
 client.cpp     | 12 +++++++++++-
 client.h       |  8 ++++++++
 mqttpacket.cpp | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--------
 mqttpacket.h   |  1 +
 4 files changed, 80 insertions(+), 9 deletions(-)

diff --git a/client.cpp b/client.cpp
index 3d8318f..81d9087 100644
--- a/client.cpp
+++ b/client.cpp
@@ -74,7 +74,10 @@ bool Client::bufferToMqttPackets(std::vector<MqttPacket> &packetQueueIn)
         while ((encodedByte & 128) != 0);
         packet_length += remaining_length_i;
 
-        // TODO: unauth client can't send many bytes
+        if (!authenticated && packet_length >= 1024*1024)
+        {
+            throw ProtocolError("An unauthenticated client sends a packet of 1 MB or bigger? Probably it's just random bytes.");
+        }
 
         if (packet_length <= getBufBytesUsed())
         {
@@ -99,6 +102,13 @@ bool Client::bufferToMqttPackets(std::vector<MqttPacket> &packetQueueIn)
     // TODO: reset buffer to normal size after a while of not needing it, or not needing the extra space.
 }
 
+void Client::setClientProperties(const std::string &clientId, const std::string username, bool connectPacketSeen)
+{
+    this->clientid = clientId;
+    this->username = username;
+    this->connectPacketSeen = connectPacketSeen;
+}
+
 
 
 
diff --git a/client.h b/client.h
index dbac6da..d4a7434 100644
--- a/client.h
+++ b/client.h
@@ -7,6 +7,7 @@
 
 #include "threaddata.h"
 #include "mqttpacket.h"
+#include "exceptions.h"
 
 #define CLIENT_BUFFER_SIZE 1024
 #define MQTT_HEADER_LENGH 2
@@ -26,7 +27,9 @@ class Client
     int ri = 0;
 
     bool authenticated = false;
+    bool connectPacketSeen = false;
     std::string clientid;
+    std::string username;
 
     ThreadData_p threadData;
 
@@ -55,6 +58,11 @@ public:
     int getFd() { return fd;}
     bool readFdIntoBuffer();
     bool bufferToMqttPackets(std::vector<MqttPacket> &packetQueueIn);
+    void setClientProperties(const std::string &clientId, const std::string username, bool connectPacketSeen);
+    void setAuthenticated(bool value) { authenticated = value;}
+    bool getAuthenticated() { return authenticated; }
+    bool hasConnectPacketSeen() { return connectPacketSeen; }
+
 
 };
 
diff --git a/mqttpacket.cpp b/mqttpacket.cpp
index 4872d34..2c1488f 100644
--- a/mqttpacket.cpp
+++ b/mqttpacket.cpp
@@ -7,24 +7,25 @@ MqttPacket::MqttPacket(char *buf, size_t len, size_t fixed_header_length, Client
     sender(sender)
 {
     unsigned char _packetType = buf[0] >> 4;
-    packetType = (PacketType)_packetType; // TODO: veryify some other things and set to invalid if doesn't match
+    packetType = (PacketType)_packetType;
+    pos += fixed_header_length;
 
     std::memcpy(&bites[0], buf, len);
 }
 
 void MqttPacket::handle()
 {
-    pos += fixed_header_length;
-
     if (packetType == PacketType::CONNECT)
         handleConnect();
 }
 
 void MqttPacket::handleConnect()
 {
+    if (sender->hasConnectPacketSeen())
+        throw ProtocolError("Client already sent a CONNECT.");
+
     // TODO: Do all packets have a variable header?
-    variable_header_length = (bites[fixed_header_length] << 8) | (bites[fixed_header_length+1]);
-    pos += 2;
+    variable_header_length = readTwoBytesToUInt16();
 
     if (variable_header_length == 4)
     {
@@ -36,12 +37,54 @@ void MqttPacket::handleConnect()
         if (magic_marker == "MQTT" && protocol_level == 0x04)
         {
             protocolVersion = ProtocolVersion::Mqtt311;
+
+            char flagByte = readByte();
+            bool reserved = !!(flagByte & 0b00000001);
+
+            if (reserved)
+                throw ProtocolError("Protocol demands reserved flag in CONNECT is 0");
+
+
+            bool user_name_flag = !!(flagByte & 0b10000000);
+            bool password_flag = !!(flagByte & 0b01000000);
+            bool will_retain = !!(flagByte & 0b00100000);
+            char will_qos = (flagByte & 0b00011000) >> 3;
+            bool will_flag = !!(flagByte & 0b00000100);
+            bool clean_session = !!(flagByte & 0b00000010);
+
+            uint16_t keep_alive = readTwoBytesToUInt16();
+
+            uint16_t client_id_length = readTwoBytesToUInt16();
+            std::string client_id(readBytes(client_id_length), client_id_length);
+
+            std::string username;
+            std::string password;
+
+            if (will_flag)
+            {
+
+            }
+            if (user_name_flag)
+            {
+                uint16_t user_name_length = readTwoBytesToUInt16();
+                username = std::string(readBytes(user_name_length), user_name_length);
+            }
+            if (password_flag)
+            {
+                uint16_t password_length = readTwoBytesToUInt16();
+                password = std::string(readBytes(password_length), password_length);
+            }
+
+            sender->setClientProperties(clientid, username, true);
+
         }
     }
     else if (variable_header_length == 6)
     {
-        throw new ProtocolError("Only MQTT 3.1.1 implemented.");
+        throw ProtocolError("Only MQTT 3.1.1 implemented.");
     }
+
+    throw ProtocolError("Unprogrammed sequence in CONNECT.");
 }
 
 char *MqttPacket::readBytes(size_t length)
@@ -59,11 +102,20 @@ char MqttPacket::readByte()
     if (pos + 1 > bites.size())
         throw ProtocolError("Invalid packet: header specifies invalid length.");
 
-    char b = bites[pos];
-    pos++;
+    char b = bites[pos++];
     return b;
 }
 
+uint16_t MqttPacket::readTwoBytesToUInt16()
+{
+    if (pos + 2 > bites.size())
+        throw ProtocolError("Invalid packet: header specifies invalid length.");
+
+    uint16_t i = bites[pos] << 8 | bites[pos+1];
+    pos += 2;
+    return i;
+}
+
 
 
 std::string MqttPacket::getClientId()
diff --git a/mqttpacket.h b/mqttpacket.h
index fbba082..c61af48 100644
--- a/mqttpacket.h
+++ b/mqttpacket.h
@@ -34,6 +34,7 @@ public:
     void handleConnect();
     char *readBytes(size_t length);
     char readByte();
+    uint16_t readTwoBytesToUInt16();
 };
 
 #endif // MQTTPACKET_H
--
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