A lot of changes and fixes in NAT and radix tree

Included MAC address into the NAT data structure
New chunking algorithms
Fixed memory leaks in RT code
(and more)

src/nat.c

@@ -20,7 +20,11 @@
 #include <stdlib.h>		/* malloc */
 #include <time.h>		/* time */
 
+#include "ipv4.h"
+#include "ipv6.h"
+#include "nat.h"
 #include "radixtree.h"
+#include "wrapper.h"
 
 struct s_radixtree_nat6 {
 	struct s_ipv6_addr	ipv6;
@@ -39,7 +43,7 @@ struct s_radixtree_nat4 {
 radixtree_t *nat6_tcp, *nat6_udp, *nat6_icmp,
 	    *nat4_tcp, *nat4_udp, *nat4_icmp;
 
-void nat_init()
+void nat_init(void)
 {
 	nat6_tcp  = radixtree_create();
 	nat6_udp  = radixtree_create();
@@ -50,33 +54,36 @@ void nat_init()
 	nat4_icmp = radixtree_create();
 }
 
-void nat_quit()
+void nat_quit(void)
 {
-	/* 128 + 16 + 32 + 16 = 198 / 6 = 33 */
+	/* 128 + 16 + 32 + 16 = 192 / 6 = 32 */
-	radixtree_destroy(&nat6_tcp,  33);
+	radixtree_destroy(nat6_tcp,  32);
-	radixtree_destroy(&nat6_udp,  33);
+	radixtree_destroy(nat6_udp,  32);
-	radixtree_destroy(&nat6_icmp, 33);
+	radixtree_destroy(nat6_icmp, 32);
 
 	/* 32 + 16 + 16 + 8 = 72 / 6 = 12 */
-	radixtree_destroy(&nat4_tcp,  12);
+	radixtree_destroy(nat4_tcp,  12);
-	radixtree_destroy(&nat4_udp,  12);
+	radixtree_destroy(nat4_udp,  12);
-	radixtree_destroy(&nat4_icmp, 12);
+	radixtree_destroy(nat4_icmp, 12);
 }
 
 struct s_nat *nat_out(radixtree_t *nat_proto6, radixtree_t *nat_proto4,
 		      struct s_ipv6_addr ipv6_src, struct s_ipv6_addr ipv6_dst,
 		      unsigned short	 port_src, unsigned short     port_dst)
 {
-	radixtree_t *result, *connection;
+	struct s_nat *result, *connection;
+
+	struct s_radixtree_nat4 radixsearch4;
+	struct s_radixtree_nat6 radixsearch6;
 
 	/* create structure to search in the tree */
-	struct s_radixtree_nat6 radixsearch6;
 	radixsearch6.ipv6 = ipv6_src;
-	radixsearch6.ipv4 = ipv6_to_ipv4(&ipv6_dst);
+	ipv6_to_ipv4(&ipv6_dst, &radixsearch6.ipv4);
 	radixsearch6.port_src = port_src;
 	radixsearch6.port_dst = port_dst;
 
-	if ((result = radixtree_lookup(nat_proto6, radixtree_outgoing_chunker, &radixsearch6)) == NULL) {
+	if ((result = (struct s_nat *) radixtree_lookup(nat_proto6, radixtree_ipv6_chunker, &radixsearch6)) == NULL) {
+		/* if no connection is found, let's create one */
 		if ((connection = (struct s_nat *) malloc(sizeof(struct s_nat))) == NULL) {
 			fprintf(stderr, "[Error] Lack of free memory\n");
 			return NULL;
@@ -86,48 +93,50 @@ struct s_nat *nat_out(radixtree_t *nat_proto6, radixtree_t *nat_proto4,
 		connection->ipv4 = radixsearch6.ipv4;
 		connection->ipv6_port_src = port_src;
 		connection->ipv4_port_dst = port_dst;
-		result->last_packet = time(NULL);
+		connection->last_packet = time(NULL);
 
 		/* generate some outgoing port */
 		do {
 			/* return port from range 1024 - 65535 */
 			connection->ipv4_port_src = (rand() % 64511) + 1024;
 
-			result = radixtree_lookup(nat_proto6, radixtree_outgoing_chunker, &radixsearch6);
+			result = radixtree_lookup(nat_proto6, radixtree_ipv6_chunker, &radixsearch6);
 		} while (result != NULL);
 
 		/* save this connection to the NAT table (to *both* of them) */
-		struct s_radixtree_nat4 radixsearch4;
 		radixsearch4.addr = radixsearch6.ipv4;
 		radixsearch4.port_src = port_dst;
 		radixsearch4.port_dst = connection->ipv4_port_src;
 		radixsearch4.zeros = 0x0;
 
-		radixtree_insert(nat_proto6, radixtree_outgoing_chunker, &radixsearch6, connection);
+		radixtree_insert(nat_proto6, radixtree_ipv6_chunker, &radixsearch6, connection);
-		radixtree_insert(nat_proto4, radixtree_incoming_chunker, &radixsearch4, connection);
+		radixtree_insert(nat_proto4, radixtree_ipv4_chunker, &radixsearch4, connection);
 
 		return connection;
 	} else {
+		/* when connection is found, refresh it and return */
 		result->last_packet = time(NULL);
 		return result;
 	}
 }
 
-struct s_nat *nat_in(radixtree_t *nat_proto, struct s_ipv4_addr ipv4_src,
+struct s_nat *nat_in(radixtree_t *nat_proto4, struct s_ipv4_addr ipv4_src,
 		     unsigned short port_src, unsigned short port_dst)
 {
-	radixtree_t *result;
+	struct s_nat *result;
 
 	/* create structure to search in the tree */
-	struct s_radixtree_nat4 radixsearch;
+	struct s_radixtree_nat4 radixsearch4;
-	radixsearch.addr = ipv4_src;
+	radixsearch4.addr = ipv4_src;
-	radixsearch.port_src = port_src;
+	radixsearch4.port_src = port_src;
-	radixsearch.port_dst = port_dst;
+	radixsearch4.port_dst = port_dst;
-	radixsearch.zeros = 0x0;
+	radixsearch4.zeros = 0x0;
 
-	if ((result = radixtree_lookup(nat_proto, radixtree_outgoing_chunker, &radixsearch)) == NULL) {
+	if ((result = (struct s_nat *) radixtree_lookup(nat_proto4, radixtree_ipv4_chunker, &radixsearch4)) == NULL) {
+		/* when connection is not found, drop the packet */
 		return NULL;
 	} else {
+		/* when connection is found, refresh it and return */
 		result->last_packet = time(NULL);
 		return result;
 	}

src/nat.h

@@ -1,6 +1,6 @@
 /*
  *  WrapSix
- *  Copyright (C) 2008-2010  Michal Zima <xhire@mujmalysvet.cz>
+ *  Copyright (C) 2008-2011  Michal Zima <xhire@mujmalysvet.cz>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU Affero General Public License as
@@ -21,11 +21,13 @@
 
 #include <time.h>		/* time_t */
 
+#include "ethernet.h"		/* s_mac_addr */
 #include "ipv4.h"		/* s_ipv4_addr */
 #include "ipv6.h"		/* s_ipv6_addr */
 #include "radixtree.h"		/* radixtree_t */
 
 struct s_nat {
+	struct s_mac_addr	mac;
 	struct s_ipv6_addr	ipv6;
 	struct s_ipv4_addr	ipv4;
 	unsigned short		ipv6_port_src;
@@ -37,13 +39,13 @@ struct s_nat {
 extern radixtree_t *nat6_tcp, *nat6_udp, *nat6_icmp,
 		   *nat4_tcp, *nat4_udp, *nat4_icmp;
 
-void nat_init();
+void nat_init(void);
-void nat_quit();
+void nat_quit(void);
 
 struct s_nat *nat_out(radixtree_t *nat_proto6, radixtree_t *nat_proto4,
 		      struct s_ipv6_addr ipv6_src, struct s_ipv6_addr ipv6_dst,
 		      unsigned short	 port_src, unsigned short     port_dst);
-struct s_nat *nat_in(radixtree_t *nat_proto, struct s_ipv4_addr ipv4_src,
+struct s_nat *nat_in(radixtree_t *nat_proto4, struct s_ipv4_addr ipv4_src,
 		     unsigned short port_src, unsigned short port_dst);
 
 #endif /* NAT_H */

src/radixtree.c

@@ -1,6 +1,6 @@
 /*
  *  WrapSix
- *  Copyright (C) 2008-2010  Michal Zima <xhire@mujmalysvet.cz>
+ *  Copyright (C) 2008-2012  Michal Zima <xhire@mujmalysvet.cz>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU Affero General Public License as
@@ -16,7 +16,13 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-radixtree_t *radixtree_create()
+#include <stdio.h>		/* fprintf */
+#include <stdlib.h>		/* free, malloc */
+#include <string.h>		/* memcpy */
+
+#include "radixtree.h"
+
+radixtree_t *radixtree_create(void)
 {
 	radixtree_t *radixtree;
 
@@ -61,7 +67,7 @@ void radixtree_insert(radixtree_t *root,
 	for (i = 0; i < chunk_count; i++) {
 		unsigned char id;
 
-		id = chunk[i];
+		id = chunks[i];
 
 		if (i == chunk_count - 1) {
 			tmp->array[id] = data;
@@ -75,6 +81,8 @@ void radixtree_insert(radixtree_t *root,
 		tmp = tmp->array[id];
 		tmp->count++;
 	}
+
+	free(chunks);
 }
 
 void radixtree_delete(radixtree_t *root,
@@ -94,7 +102,7 @@ void radixtree_delete(radixtree_t *root,
 	for (i = 0; i < chunk_count; i++) {
 		unsigned char id;
 
-		id = chunk[i];
+		id = chunks[i];
 
 		/* already deleted? may cause data inconsistency! */
 		if (tmp->array[id] == NULL) {
@@ -130,68 +138,104 @@ void radixtree_delete(radixtree_t *root,
 		tmp = next;
 		tmp->count--;
 	}
+
+	free(chunks);
 }
 
-radixtree_t *radixtree_lookup(radixtree_t *root,
+void *radixtree_lookup(radixtree_t *root,
 		       unsigned char *(chunker)(void *data, unsigned char *count),
 		       void *data)
 {
 	radixtree_t *tmp;
-	unsigned char i, chunk_count;
+	unsigned char i, chunk_count, id;
 	unsigned char *chunks;
 
 	chunks = chunker(data, &chunk_count);
 
 	tmp = root;
 
-	for (i = 0; i < chunk_count; i++) {
+	for (i = 0;; i++) {
-		unsigned char id;
+		id = chunks[i];
-
-		id = chunk[i];
 
+		/* leave the for cycle before tmp gets overwritten,
+		 * if the final result was found */
 		if (i == chunk_count - 1) {
+			free(chunks);
 			return tmp->array[id];
 		}
 
+		/* leave if there is no result */
 		if (tmp->array[id] == NULL) {
+			free(chunks);
 			return NULL;
 		}
 
+		/* go deeper */
 		tmp = tmp->array[id];
 	}
+
+	/* we never get here ;c) */
 }
 
-unsigned char *radixtree_outgoing_chunker(void *data, unsigned char *count)
+unsigned char *radixtree_ipv6_chunker(void *data, unsigned char *count)
 {
 	short i;
 	unsigned char counter;
+	unsigned char *chunks;
+	unsigned char *cdata = (unsigned char *) data;
 
-	counter = 198 / 6;
+	counter = 192 / 6;
 	memcpy(count, &counter, sizeof(unsigned char));
 
-	unsigned char chunks[counter];
+	if ((chunks = (unsigned char *) malloc(counter * sizeof(unsigned char))) == NULL) {
+		fprintf(stderr, "[Error] Lack of free memory\n");
+		return NULL;
+	}
 
-	/* 128 + 16 + 32 + 16 - 6 = 192 */
+	/*
-	for (i = 192, counter = 0; i >= 0; i -= 6, counter++) {
+	 *   3 == 0000 0011 == 0x03
-		chunks[counter] = (*data >> i) & 63;	/* 63 == 0011 1111 */
+	 *  15 == 0000 1111 == 0x0f
+	 *  48 == 0011 0000 == 0x30
+	 *  60 == 0011 1100 == 0x3c
+	 *  63 == 0011 1111 == 0x3f
+	 * 192 == 1100 0000 == 0xc0
+	 * 240 == 1111 0000 == 0xf0
+	 * 252 == 1111 1100 == 0xfc
+	 */
+	for (i = 0, counter = 0; counter < *count; i++) {
+		chunks[counter++] = cdata[i] & 0x3f;
+		chunks[counter++] = ((cdata[i] & 0xc0) >> 6) | ((cdata[i + 1] & 0x0f) << 2);
+		i++;
+		chunks[counter++] = ((cdata[i] & 0xf0) >> 4) | ((cdata[i + 1] & 0x03) << 4);
+		i++;
+		chunks[counter++] = ((cdata[i] & 0xfc) >> 2);
 	}
 
 	return chunks;
 }
 
-unsigned char *radixtree_incoming_chunker(void *data, unsigned char *count)
+unsigned char *radixtree_ipv4_chunker(void *data, unsigned char *count)
 {
 	short i;
 	unsigned char counter;
+	unsigned char *chunks;
+	unsigned char *cdata = (unsigned char *) data;
 
 	counter = 72 / 6;
 	memcpy(count, &counter, sizeof(unsigned char));
 
-	unsigned char chunks[counter];
+	if ((chunks = (unsigned char *) malloc(counter * sizeof(unsigned char))) == NULL) {
+		fprintf(stderr, "[Error] Lack of free memory\n");
+		return NULL;
+	}
 
-	/* 32 + 16 + 16 + 8 - 6 = 66 */
+	for (i = 0, counter = 0; counter < *count; i++) {
-	for (i = 66, counter = 0; i >= 0; i -= 6, counter++) {
+		chunks[counter++] = cdata[i] & 0x3f;
-		chunks[counter] = (*data >> i) & 63;	/* 63 == 0011 1111 */
+		chunks[counter++] = ((cdata[i] & 0xc0) >> 6) | ((cdata[i + 1] & 0x0f) << 2);
+		i++;
+		chunks[counter++] = ((cdata[i] & 0xf0) >> 4) | ((cdata[i + 1] & 0x03) << 4);
+		i++;
+		chunks[counter++] = ((cdata[i] & 0xfc) >> 2);
 	}
 
 	return chunks;

src/radixtree.h

@@ -1,6 +1,6 @@
 /*
  *  WrapSix
- *  Copyright (C) 2008-2010  Michal Zima <xhire@mujmalysvet.cz>
+ *  Copyright (C) 2008-2011  Michal Zima <xhire@mujmalysvet.cz>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU Affero General Public License as
@@ -16,6 +16,9 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifndef RADIXTREE_H
+#define RADIXTREE_H
+
 #define CHUNK_SIZE	6
 #define ARRAY_SIZE	64	/* 2 ^ CHUNK_SIZE */
 
@@ -24,7 +27,7 @@ typedef struct radixtree {
 	unsigned int count;
 } radixtree_t;
 
-radixtree_t *radixtree_create();
+radixtree_t *radixtree_create(void);
 void radixtree_destroy(radixtree_t *t, unsigned char depth);
 void radixtree_insert(radixtree_t *root,
 		      unsigned char *(chunker)(void *data, unsigned char *count),
@@ -32,8 +35,10 @@ void radixtree_insert(radixtree_t *root,
 void radixtree_delete(radixtree_t *root,
 		      unsigned char *(chunker)(void *data, unsigned char *count),
 		      void *data);
-radixtree_t *radixtree_lookup(radixtree_t *root,
+void *radixtree_lookup(radixtree_t *root,
 		      unsigned char *(chunker)(void *data, unsigned char *count),
 		      void *data);
-unsigned char *radixtree_outgoing_chunker(void *data, unsigned char *count);
+unsigned char *radixtree_ipv6_chunker(void *data, unsigned char *count);
-unsigned char *radixtree_incoming_chunker(void *data, unsigned char *count);
+unsigned char *radixtree_ipv4_chunker(void *data, unsigned char *count);
+
+#endif /* RADIXTREE_H */