From f21e85b574d807e2dd4feafcb51adfc538a199ec Mon Sep 17 00:00:00 2001
From: Erik Ekman <yarrick@kryo.se>
Date: Mon, 5 Jun 2006 14:37:58 +0000
Subject: [PATCH] Send dns query on start

---
 dns.c    | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 dns.h    |  1 +
 dnstun.c |  1 +
 3 files changed, 67 insertions(+)

diff --git a/dns.c b/dns.c
index ec96328..069f2e3 100644
--- a/dns.c
+++ b/dns.c
@@ -30,6 +30,8 @@
 
 #include "dns.h"
 
+static int host2dns(const char *, char *, int);
+
 struct sockaddr_in peer;
 
 int 
@@ -83,3 +85,66 @@ dns_set_peer(const char *host)
 	peer.sin_port = htons(53);
 	peer.sin_addr = *((struct in_addr *) h->h_addr);
 }
+
+void 
+dns_query(int fd, char *host, int type)
+{
+	char *p;
+	int len;
+	int peerlen;
+	char buf[1024];
+	HEADER *header;
+	
+	len = 0;
+	memset(buf, 0, sizeof(buf));
+
+	header = (HEADER*)buf;	
+	
+	header->id = 0;
+	header->qr = 0;
+	header->opcode = 0;
+	header->aa = 0;
+	header->tc = 0;
+	header->rd = 1;
+	header->ra = 0;
+
+	header->qdcount = htons(1);
+
+	p = buf + sizeof(HEADER);
+	p += host2dns(host, p, strlen(host));	
+
+	PUTSHORT(type, p);
+	PUTSHORT(C_IN, p);
+
+	peerlen = sizeof(peer);
+
+	len = p - buf;
+	sendto(fd, buf, len+1, 0, (struct sockaddr*)&peer, peerlen);
+}
+
+static int
+host2dns(const char *host, char *buffer, int size)
+{
+	char *h;
+	char *p;
+	char *word;
+
+	h = strdup(host);
+	memset(buffer, 0, size);
+	p = buffer;
+	
+	word = strtok(h, ".");
+	while(word) {
+		*p++ = (char)strlen(word);
+		memcpy(p, word, strlen(word));
+		p += strlen(word);
+
+		word = strtok(NULL, ".");
+	}
+
+	*p++ = 0;
+
+	free(h);
+
+	return p - buffer;
+}
diff --git a/dns.h b/dns.h
index 647febe..21f9a0b 100644
--- a/dns.h
+++ b/dns.h
@@ -25,5 +25,6 @@ int open_dns();
 void close_dns(int);
 
 void dns_set_peer(const char *);
+void dns_query(int, char *, int);
 
 #endif /* _DNS_H_ */
diff --git a/dnstun.c b/dnstun.c
index df6ab2e..c8e0b02 100644
--- a/dnstun.c
+++ b/dnstun.c
@@ -28,6 +28,7 @@ main()
 	open_tun();
 	dnssock = open_dns();
 	dns_set_peer("192.168.11.101");
+	dns_query(dnssock, "kryo.se", 1);
 
 	close_dns(dnssock);
 	close_tun();