From 33f8a07aa6d5225ed4371991bd5c2fcf0a7821d0 Mon Sep 17 00:00:00 2001
From: Erik Ekman <yarrick@kryo.se>
Date: Mon, 5 Jun 2006 13:38:10 +0000
Subject: [PATCH] Added dns.[ch], for udp messaging

---
 Makefile |  2 +-
 dns.c    | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 dns.h    | 25 ++++++++++++++++++++
 dnstun.c |  8 ++++++-
 4 files changed, 103 insertions(+), 2 deletions(-)
 create mode 100644 dns.c
 create mode 100644 dns.h

diff --git a/Makefile b/Makefile
index b11154b..79a6aff 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 CC = gcc
 OUT = dnstun
-OBJS = dnstun.o tun.o
+OBJS = dnstun.o tun.o dns.o
 
 OS = `uname | tr "a-z" "A-Z"`
 
diff --git a/dns.c b/dns.c
new file mode 100644
index 0000000..4a6bc93
--- /dev/null
+++ b/dns.c
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2006 
+ * Bjorn Andersson <flex@kryo.se>,
+ * Erik Ekman <yarrick@kryo.se>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <arpa/nameser.h>
+#include <time.h>
+#include <err.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+
+#include "dns.h"
+
+int 
+open_dns() 
+{
+	int fd;
+	int flag;
+	struct sockaddr_in addr;
+
+	bzero(&addr, sizeof(addr));
+	addr.sin_family = AF_INET;
+	addr.sin_port = 0; 			// choose an available port
+	addr.sin_addr.s_addr = INADDR_ANY; 	// listen on 0.0.0.0
+
+	fd = socket(AF_INET, SOCK_DGRAM, 0);
+	if(fd < 0) {
+		err(1, "Could not get UDP socket");
+	}
+
+	flag = 1;
+#ifdef SO_REUSEPORT
+	setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &flag, sizeof(flag));
+#endif
+	setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof(flag));
+
+	if(bind(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
+		err(1, "Could not bind UDP socket locally");
+	}
+
+	printf("Opened UDP socket\n");
+
+	return fd;
+}
+
+void
+close_dns(int fd)
+{
+	close(fd);
+}
diff --git a/dns.h b/dns.h
new file mode 100644
index 0000000..b26b9fb
--- /dev/null
+++ b/dns.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2006 
+ * Bjorn Andersson <flex@kryo.se>,
+ * Erik Ekman <yarrick@kryo.se>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef _DNS_H_
+#define _DNS_H_
+
+int open_dns();
+void close_dns(int);
+
+#endif /* _DNS_H_ */
diff --git a/dnstun.c b/dnstun.c
index ffbc370..ea66cc3 100644
--- a/dnstun.c
+++ b/dnstun.c
@@ -20,12 +20,18 @@
 #include <stdint.h>
 
 #include "tun.h"
+#include "dns.h"
 
 int
 main()
 {
-	open_tun();
+	int dnssock;
 
+	open_tun();
+	dnssock = open_dns();
+	
+
+	close_dns(dnssock);
 	close_tun();	
 
 	return 0;