From 5b611332f020c9fc94b5992188dd0701fdf4f327 Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Sat, 7 Feb 2015 01:15:19 +0100
Subject: [PATCH] Move TUNProtocol into its own file.

---
 tunprotocol.cpp | 93 +++++++++++++++++++++++++++++++++++++++++++++++++
 tunprotocol.h   | 20 +++++++++++
 2 files changed, 113 insertions(+)
 create mode 100644 tunprotocol.cpp
 create mode 100644 tunprotocol.h

diff --git a/tunprotocol.cpp b/tunprotocol.cpp
new file mode 100644
index 0000000..b8b63a3
--- /dev/null
+++ b/tunprotocol.cpp
@@ -0,0 +1,93 @@
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <linux/if.h>
+#include <linux/if_tun.h>
+
+#include "tunprotocol.h"
+
+using namespace std;
+
+namespace {
+
+int tun_open(const char *name) {
+	struct ifreq ifr;
+
+	int fd = open("/dev/net/tun", O_RDWR);
+	if (fd == -1) {
+		perror("/dev/net/tun");
+		exit(1);
+	}
+
+	memset(&ifr, 0, sizeof(ifr));
+	ifr.ifr_flags = IFF_TUN;
+	strncpy(ifr.ifr_name, name, IFNAMSIZ);
+
+	int err = ioctl(fd, TUNSETIFF, &ifr);
+	if (err == -1) {
+		perror("ioctl(TUNSETIFF)");
+		exit(-1);
+	}
+
+	return fd;
+}
+
+}  // namespace
+
+TUNProtocol::TUNProtocol(const char *devname)
+	: tunfd(tun_open(devname)) {
+}
+
+void TUNProtocol::send_packet(uint16_t proto, const string &data)
+{
+	char buf[4096];
+
+	char *ptr = buf;
+	uint16_t flags = 0;
+	memcpy(ptr, &flags, sizeof(flags));
+	ptr += sizeof(flags);
+
+	proto = htons(proto);
+	memcpy(ptr, &proto, sizeof(proto));
+	ptr += sizeof(proto);
+
+	memcpy(ptr, data.data(), data.size());
+
+	int len = sizeof(flags) + sizeof(proto) + data.size();
+	if (write(tunfd, buf, len) != len) {
+		perror("write");
+		return;
+	}
+}
+
+int TUNProtocol::fd() const
+{
+	return tunfd;
+}
+
+void TUNProtocol::read_packet(Protocol *sender)
+{
+	char buf[4096];
+	int ret = read(tunfd, buf, sizeof(buf));
+	if (ret == -1) {
+		perror("read");
+		exit(1);
+	}
+	if (ret == 0) {
+		fprintf(stderr, "tunfd EOF\n");
+		exit(1);
+	}
+	
+	char *ptr = buf;
+	uint16_t flags = *(uint16_t *)ptr;
+	ptr += 2;
+	uint16_t proto = ntohs(*(uint16_t *)ptr);
+	ptr += 2;
+	//fprintf(stderr, "tun packet: flags=%x proto=%x len=%d\n",
+	//	flags, proto, ret - 4);
+	sender->send_packet(proto, string(ptr, buf + ret));
+}
+
diff --git a/tunprotocol.h b/tunprotocol.h
new file mode 100644
index 0000000..cfe3b46
--- /dev/null
+++ b/tunprotocol.h
@@ -0,0 +1,20 @@
+#ifndef _TUNPROTOCOL_H
+#define _TUNPROTOCOL_H 1
+
+#include "protocol.h"
+
+#include <stdint.h>
+#include <string>
+
+class TUNProtocol : public Protocol {
+public:
+	TUNProtocol(const char *devname);
+	virtual void send_packet(uint16_t proto, const std::string &data);
+	virtual int fd() const;
+	void read_packet(Protocol* sender);
+
+private:
+	int tunfd;
+};
+
+#endif  // !defined(_TUNPROTOCOL_H)
-- 
2.39.2