From 9bb84fe05d093294d660a200fc88d86d68469128 Mon Sep 17 00:00:00 2001
From: Erik Ekman <yarrick@kryo.se>
Date: Mon, 5 Jun 2006 20:05:11 +0000
Subject: [PATCH] first try on send functionality

---
 dns.c    | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++----
 dns.h    |  4 +--
 dnsd.c   |  9 ++++--
 dnstun.c | 16 ++++++++--
 4 files changed, 104 insertions(+), 14 deletions(-)

diff --git a/dns.c b/dns.c
index 4a5cd8f..f531177 100644
--- a/dns.c
+++ b/dns.c
@@ -35,6 +35,13 @@ static int host2dns(const char *, char *, int);
 struct sockaddr_in peer;
 char topdomain[256];
 
+// Current IP packet
+char activepacket[4096];
+int lastlen;
+int packetpos;
+int packetlen;
+uint16_t chunkid;
+
 static int
 readname(char *packet, char *dst, char *src)
 {
@@ -128,6 +135,9 @@ open_dns(const char *host, const char *domain)
 	strncpy(topdomain, domain, sizeof(topdomain) - 2);
 	topdomain[sizeof(topdomain) - 1] = 0;
 
+	// Init chunk id
+	chunkid = 0;
+
 	return fd;
 }
 
@@ -137,12 +147,77 @@ close_dns(int fd)
 	close(fd);
 }
 
+int
+dns_sending()
+{
+	return (packetlen != 0);
+}
+
+static void
+dns_send_chunk(int fd)
+{
+	int avail;
+	char *p;
+
+	p = activepacket;
+	p += packetpos;
+	avail = packetlen - packetpos;
+	lastlen = dns_write(fd, ++chunkid, p, avail);
+	printf("Sent %d bytes of %d remaining\n", lastlen, avail);
+}
+
+void
+dns_handle_tun(int fd, char *data, int len)
+{
+	memcpy(activepacket, data, MIN(len, sizeof(activepacket)));
+	lastlen = 0;
+	packetpos = 0;
+	packetlen = len;
+
+	dns_send_chunk(fd);
+}
+
+static int
+dns_handle_reply(int fd, char *data, int len)
+{
+	uint16_t id;
+	char *p;
+
+	p = data;
+	READSHORT(id, p);
+
+	// Handle ACKing
+	if (dns_sending() && id == chunkid) {
+		// Got ACK on sent packet
+		packetpos += lastlen;
+		if (packetpos == packetlen) {
+			// Packet completed
+			printf("IP packet size %d sent successfully!\n", packetlen);
+			packetpos = 0;
+			packetlen = 0;
+			lastlen = 0;
+		} else {
+			// More to send
+			dns_send_chunk(fd);
+		}
+	}
+
+	// Detect if any data is attached
+	// TODO
+	
+	return 0;
+}
+
 void
 dns_ping(int dns_fd)
 {
-	dns_write(dns_fd, dns_fd, 
-	 "AAAAAAAAAAAKRYOAAAAAAAAAAAKRYOAAAAAAAAAAAAAKRYOAAAAAAAAAAAAAKRYOAAAAAAAAAAAAAAAKRYOAAAAAAAAAAAAAKRYOAAAAAAAAAAAAAAAAAAB",
-	 119);
+	if (dns_sending()) {
+		// Resend latest chunk
+		printf("No reply on chunk, resending\n");
+		dns_send_chunk(dns_fd);
+	} else {
+		dns_write(dns_fd, dns_fd, "\0", 1);
+	}
 }
 
 void 
@@ -178,7 +253,7 @@ dns_query(int fd, int id, char *host, int type)
 	peerlen = sizeof(peer);
 
 	len = p - buf;
-	sendto(fd, buf, len+1, 0, (struct sockaddr*)&peer, peerlen);
+	sendto(fd, buf, len, 0, (struct sockaddr*)&peer, peerlen);
 }
 
 int
@@ -248,7 +323,7 @@ dns_read(int fd, char *buf, int buflen)
 	printf("Read %d bytes DNS reply\n", r);
 
 	if(r == -1) {
-		perror("recvfrom");
+		perror("recv");
 	} else {
 		header = (HEADER*)packet;
 		
@@ -277,8 +352,10 @@ dns_read(int fd, char *buf, int buflen)
 					READSHORT(port, r);
 					READNAME(packet, host, r);
 				}
-				printf("%s\n", name);
+			//	printf("%s\n", name);
 			}
+			// Is any data attached?
+			return dns_handle_reply(fd, packet, r);
 		}
 	}
 
diff --git a/dns.h b/dns.h
index cb84fc3..3678076 100644
--- a/dns.h
+++ b/dns.h
@@ -17,11 +17,11 @@
 #ifndef _DNS_H_
 #define _DNS_H_
 
-extern struct sockaddr_in peer;
-
 int open_dns(const char *, const char *);
 void close_dns(int);
 
+int dns_sending();
+void dns_handle_tun(int, char *, int);
 void dns_ping(int);
 void dns_query(int, int, char *, int);
 int dns_write(int, int, char *, int);
diff --git a/dnsd.c b/dnsd.c
index deabf82..7282332 100644
--- a/dnsd.c
+++ b/dnsd.c
@@ -150,7 +150,7 @@ host2dns(const char *host, char *buffer, int size)
 }
 
 static void
-dnsd_respond(int fd, struct sockaddr_in from)
+dnsd_respond(int fd, short id, struct sockaddr_in from)
 {
 	int len;
 	int size;
@@ -163,7 +163,7 @@ dnsd_respond(int fd, struct sockaddr_in from)
 	len = 0;
 	header = (HEADER*)buf;	
 
-	header->id = 0;
+	header->id = id;
 	header->qr = 1;
 	header->opcode = 0;
 	header->aa = 1;
@@ -194,6 +194,7 @@ dnsd_read(int fd, char *buf, int buflen)
 {
 	int i;
 	int r;
+	short id;
 	short type;
 	short class;
 	short qdcount;
@@ -214,6 +215,8 @@ dnsd_read(int fd, char *buf, int buflen)
 	} else {
 		header = (HEADER*)packet;
 		
+		id = ntohs(header->id);
+
 		data = packet + sizeof(HEADER);
 
 		if(!header->qr) {
@@ -227,7 +230,7 @@ dnsd_read(int fd, char *buf, int buflen)
 				
 				printf("%s %d %d\n", name, type, class);
 				
-				dnsd_respond(fd, from);
+				dnsd_respond(fd, id, from);
 			}
 		}
 	}
diff --git a/dnstun.c b/dnstun.c
index 149ade0..ff75dcb 100644
--- a/dnstun.c
+++ b/dnstun.c
@@ -41,7 +41,7 @@ tunnel(int tun_fd, int dns_fd)
 	int i;
 	int read;
 	fd_set fds;
-	char buf[1024];
+	char buf[4096];
 	struct timeval tv;
 	
 	while (running) {
@@ -49,7 +49,9 @@ tunnel(int tun_fd, int dns_fd)
 		tv.tv_usec = 0;
 
 		FD_ZERO(&fds);
-		FD_SET(tun_fd, &fds);
+		if (!dns_sending()) {
+			FD_SET(tun_fd, &fds);
+		}
 		FD_SET(dns_fd, &fds);
 
 		i = select(MAX(tun_fd, dns_fd) + 1, &fds, NULL, NULL, &tv);
@@ -65,10 +67,18 @@ tunnel(int tun_fd, int dns_fd)
 			dns_ping(dns_fd);
 		} else {
 			if(FD_ISSET(tun_fd, &fds)) {
-				
+				read = read_tun(tun_fd, buf, sizeof(buf));
+				if (read > 0) {
+					printf("Got data on tun! %d bytes\n", read);
+					dns_handle_tun(dns_fd, buf, read);
+				}
 			}
 			if(FD_ISSET(dns_fd, &fds)) {
 				read = dns_read(dns_fd, buf, sizeof(buf));
+				if (read > 0) {
+					printf("Got data on dns! %d bytes\n", read);
+					write_tun(tun_fd, buf, read);
+				}
 			} 
 		}
 	}