From 6ea66b7aabc106b83a49d9d8380d130486db2c5d Mon Sep 17 00:00:00 2001
From: Keith Winstein <keithw@mit.edu>
Date: Tue, 2 Aug 2011 12:49:02 -0400
Subject: [PATCH] Initial network support

---
 Makefile    |  9 ++++++---
 network.cpp | 32 ++++++++++++++++++++++++++++++++
 network.hpp | 44 ++++++++++++++++++++++++++++++++++++++++++++
 ntester.cpp | 12 ++++++++++++
 rtmnotes    | 33 +++++++++++++++++++++++++++++++++
 5 files changed, 127 insertions(+), 3 deletions(-)
 create mode 100644 network.cpp
 create mode 100644 network.hpp
 create mode 100644 ntester.cpp
 create mode 100644 rtmnotes

diff --git a/Makefile b/Makefile
index ff0a06d..08e52e8 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
-source = parse.cpp parserstate.cpp parser.cpp templates.cpp terminal.cpp termemu.cpp parseraction.cpp terminalfunctions.cpp swrite.cpp terminalframebuffer.cpp terminaldispatcher.cpp terminaluserinput.cpp terminaldisplay.cpp
-objects = parserstate.o parser.o templates.o terminal.o parseraction.o terminalfunctions.o swrite.o terminalframebuffer.o terminaldispatcher.o terminaluserinput.o terminaldisplay.o
+source = parse.cpp parserstate.cpp parser.cpp templates.cpp terminal.cpp termemu.cpp parseraction.cpp terminalfunctions.cpp swrite.cpp terminalframebuffer.cpp terminaldispatcher.cpp terminaluserinput.cpp terminaldisplay.cpp network.cpp ntester.cpp
+objects = parserstate.o parser.o templates.o terminal.o parseraction.o terminalfunctions.o swrite.o terminalframebuffer.o terminaldispatcher.o terminaluserinput.o terminaldisplay.o network.o
 repos = templates.rpo
-executables = parse termemu
+executables = parse termemu ntester
 
 CXX = g++
 CXXFLAGS = -g -O2 --std=c++0x -pedantic -Werror -Wall -Wextra -Weffc++ -fno-implicit-templates -fno-default-inline -pipe -D_FILE_OFFSET_BITS=64 -D_XOPEN_SOURCE=500 -D_GNU_SOURCE
@@ -15,6 +15,9 @@ parse: parse.o $(objects)
 termemu: termemu.o $(objects) parse # serialize link steps because of -frepo
 	$(CXX) $(CXXFLAGS) -o $@ termemu.o $(objects) $(LIBS)
 
+ntester: ntester.o $(objects) termemu # serialize link steps because of -frepo
+	$(CXX) $(CXXFLAGS) -o $@ ntester.o $(objects) $(LIBS)
+
 templates.o: templates.cpp
 	$(CXX) $(CXXFLAGS) -frepo -c -o $@ $<
 
diff --git a/network.cpp b/network.cpp
new file mode 100644
index 0000000..b6a8c18
--- /dev/null
+++ b/network.cpp
@@ -0,0 +1,32 @@
+#include <assert.h>
+
+#include "network.hpp"
+
+using namespace std;
+using namespace Network;
+
+template <class Payload>
+Connection<Payload>::Packet::Packet( int64_t s_seq, int64_t s_ack, Packet *s_previous, Payload s_state )
+  : seq( s_seq ), ack( s_ack ), previous( s_previous ), state( s_state )
+{
+
+}
+
+template <class Payload>
+Connection<Payload>::Packet::Packet( string wire )
+{
+  assert( wire.length() >= 32 );
+
+  seq = be64toh( (uint64_t) *wire_c );
+  reference_seq = be64toh( (uint64_t) *( wire_c + 8 ) );
+
+  tag = string( wire.begin() + 16, wire.begin() + 32 );
+
+  ack = be64toh( (uint64_t) *( wire_c + 16 ) );
+}
+
+template <class Payload>
+Connection<Payload>::Connection( const char *ip, const char *port, bool server )
+{
+
+}
diff --git a/network.hpp b/network.hpp
new file mode 100644
index 0000000..867295f
--- /dev/null
+++ b/network.hpp
@@ -0,0 +1,44 @@
+#ifndef NETWORK_HPP
+#define NETWORK_HPP
+
+#include <stdint.h>
+#include <deque>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <string>
+
+namespace Network {
+  template <class Payload>
+  class Connection {
+  private:
+    class Packet {
+    public:
+      int64_t seq;
+      int64_t reference_seq;
+
+      std::string tag;
+
+      int64_t ack;
+
+      Payload state;
+
+      Packet( int64_t s_seq, int64_t s_ack, Packet *s_previous, Payload s_state );
+      Packet( std::string wire );
+    };
+
+    int64_t next_seq;
+    int64_t next_ack;
+    int sequence_increment;
+
+    int sock;
+    struct sockaddr_in addr;
+
+    std::deque<Packet> send_queue;
+    std::deque<Packet> recv_queue;
+
+  public:
+    Connection( const char *ip, const char *port, bool server );
+  };
+}
+
+#endif
diff --git a/ntester.cpp b/ntester.cpp
new file mode 100644
index 0000000..fbca0c7
--- /dev/null
+++ b/ntester.cpp
@@ -0,0 +1,12 @@
+#include "network.hpp"
+
+class KeyStroke
+{
+public:
+  char letter;
+};
+
+int main( void )
+{
+  Network::Connection<KeyStroke> n();
+}
diff --git a/rtmnotes b/rtmnotes
new file mode 100644
index 0000000..25b1f1d
--- /dev/null
+++ b/rtmnotes
@@ -0,0 +1,33 @@
+1. server maintains:
+   every frame it has ever been in.
+
+   every packet it has ever sent.
+
+   packet has: frame no, frame it depends on (maybe nothing),
+0   server's Last Known Client Frame
+
+   client has told us the latest frame it can now contruct
+
+   some packets have transmitted frames > this recently, but those
+   frames haven't yet been acked
+
+   some packets may have transmitted frames > this long ago
+   and haven't been acked. we call those lost
+
+2. most recent frame is "current frame"
+
+   most recent frame not lost is "presumed client frame"
+
+   most recent frame acked is "last known client frame"
+
+3. goal: transmit current frame to client by most efficient means
+
+   could send packet depending on "nothing", "presumed client frame",
+   or "last known client frame"
+
+4. when client gets a packet, it tells us the latest frame it
+   can now construct
+
+5. when sending packet, server tells client last known client frame.
+   client discards all frames older than this.
+