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https://code.semirocket.science/wrapsix
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Quite good implementation of NAT
This commit is contained in:
Michal Zima
parent
3d8d8ace2a
commit
f9f2bd501b
135
src/nat.c
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135
src/nat.c
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/*
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* WrapSix
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* Copyright (C) 2008-2010 Michal Zima <xhire@mujmalysvet.cz>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdio.h>
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#include <stdlib.h> /* malloc */
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#include <time.h> /* time */
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#include "radixtree.h"
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struct s_radixtree_nat6 {
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struct s_ipv6_addr ipv6;
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struct s_ipv4_addr ipv4;
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unsigned short port_src;
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unsigned short port_dst;
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} __attribute__ ((__packed__));
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struct s_radixtree_nat4 {
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struct s_ipv4_addr addr;
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unsigned short port_src;
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unsigned short port_dst;
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unsigned char zeros; /* unused space */
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} __attribute__ ((__packed__));
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radixtree_t *nat6_tcp, *nat6_udp, *nat6_icmp,
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*nat4_tcp, *nat4_udp, *nat4_icmp;
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void nat_init()
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{
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nat6_tcp = radixtree_create();
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nat6_udp = radixtree_create();
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nat6_icmp = radixtree_create();
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nat4_tcp = radixtree_create();
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nat4_udp = radixtree_create();
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nat4_icmp = radixtree_create();
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}
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void nat_quit()
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{
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/* 128 + 16 + 32 + 16 = 198 / 6 = 33 */
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radixtree_destroy(&nat6_tcp, 33);
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radixtree_destroy(&nat6_udp, 33);
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radixtree_destroy(&nat6_icmp, 33);
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/* 32 + 16 + 16 + 8 = 72 / 6 = 12 */
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radixtree_destroy(&nat4_tcp, 12);
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radixtree_destroy(&nat4_udp, 12);
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radixtree_destroy(&nat4_icmp, 12);
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}
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struct s_nat *nat_out(radixtree_t *nat_proto6, radixtree_t *nat_proto4,
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struct s_ipv6_addr ipv6_src, struct s_ipv6_addr ipv6_dst,
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unsigned short port_src, unsigned short port_dst)
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{
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radixtree_t *result, *connection;
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/* create structure to search in the tree */
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struct s_radixtree_nat6 radixsearch6;
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radixsearch6.ipv6 = ipv6_src;
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radixsearch6.ipv4 = ipv6_to_ipv4(&ipv6_dst);
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radixsearch6.port_src = port_src;
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radixsearch6.port_dst = port_dst;
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if ((result = radixtree_lookup(nat_proto6, radixtree_outgoing_chunker, &radixsearch6)) == NULL) {
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if ((connection = (struct s_nat *) malloc(sizeof(struct s_nat))) == NULL) {
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fprintf(stderr, "[Error] Lack of free memory\n");
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return NULL;
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}
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connection->ipv6 = ipv6_src;
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connection->ipv4 = radixsearch6.ipv4;
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connection->ipv6_port_src = port_src;
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connection->ipv4_port_dst = port_dst;
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result->last_packet = time(NULL);
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/* generate some outgoing port */
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srand((unsigned int) time(NULL));
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do {
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/* return port from range 1024 - 65535 */
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connection->ipv4_port_src = (rand() % 64511) + 1024;
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result = radixtree_lookup(nat_proto6, radixtree_outgoing_chunker, &radixsearch6);
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} while (result != NULL);
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/* save this connection to the NAT table (to *both* of them) */
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struct s_radixtree_nat4 radixsearch4;
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radixsearch4.addr = radixsearch6.ipv4;
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radixsearch4.port_src = port_dst;
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radixsearch4.port_dst = connection->ipv4_port_src;
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radixsearch4.zeros = 0x0;
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radixtree_insert(nat_proto6, radixtree_outgoing_chunker, &radixsearch6, connection);
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radixtree_insert(nat_proto4, radixtree_incoming_chunker, &radixsearch4, connection);
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return connection;
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} else {
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result->last_packet = time(NULL);
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return result;
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}
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}
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struct s_nat *nat_in(radixtree_t *nat_proto, struct s_ipv4_addr ipv4_src,
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unsigned short port_src, unsigned short port_dst)
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{
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radixtree_t *result;
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/* create structure to search in the tree */
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struct s_radixtree_nat4 radixsearch;
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radixsearch.addr = ipv4_src;
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radixsearch.port_src = port_src;
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radixsearch.port_dst = port_dst;
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radixsearch.zeros = 0x0;
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if ((result = radixtree_lookup(nat_proto, radixtree_outgoing_chunker, &radixsearch)) == NULL) {
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return NULL;
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} else {
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result->last_packet = time(NULL);
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return result;
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}
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}
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49
src/nat.h
Normal file
49
src/nat.h
Normal file
@ -0,0 +1,49 @@
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/*
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* WrapSix
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* Copyright (C) 2008-2010 Michal Zima <xhire@mujmalysvet.cz>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef NAT_H
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#define NAT_H
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#include <time.h> /* time_t */
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#include "ipv4.h" /* s_ipv4_addr */
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#include "ipv6.h" /* s_ipv6_addr */
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#include "radixtree.h" /* radixtree_t */
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struct s_nat {
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struct s_ipv6_addr ipv6;
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struct s_ipv4_addr ipv4;
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unsigned short ipv6_port_src;
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unsigned short ipv4_port_src;
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unsigned short ipv4_port_dst;
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time_t last_packet; /* time of processing last packet of the connection */
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};
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extern radixtree_t *nat6_tcp, *nat6_udp, *nat6_icmp,
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*nat4_tcp, *nat4_udp, *nat4_icmp;
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void nat_init();
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void nat_quit();
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struct s_nat *nat_out(radixtree_t *nat_proto6, radixtree_t *nat_proto4,
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struct s_ipv6_addr ipv6_src, struct s_ipv6_addr ipv6_dst,
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unsigned short port_src, unsigned short port_dst);
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struct s_nat *nat_in(radixtree_t *nat_proto, struct s_ipv4_addr ipv4_src,
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unsigned short port_src, unsigned short port_dst);
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#endif /* NAT_H */
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