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Code

RAW packet transmission function

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This commit is contained in:
Michal Zima 2012-03-26 12:53:58 +02:00
parent d7a570b857
commit 5928affce6
4 changed files with 144 additions and 3 deletions
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102
src/transmitter.c Normal file
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@ -0,0 +1,102 @@
/*
* WrapSix
* 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
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <netinet/if_ether.h> /* {P,A}F_PACKET, ETH_P_*, socket, SOCK_RAW,
* setsockopt, SOL_SOCKET, SO_BINDTODEVICE, sendto */
#include <netinet/in.h> /* htons */
#include <netpacket/packet.h> /* sockaddr_ll, PACKET_OTHERHOST */
#include <stdio.h> /* fprintf, stderr, perror */
#include <unistd.h> /* close */
#include "ipv4.h"
#include "transmitter.h"
#include "wrapper.h"
struct sockaddr_ll socket_address;
int sock;
/**
* Initialize socket and all needed properties. Should be called only once on program startup.
*
* @return 0 for success
* @return 1 for failure
*/
int transmission_init(void)
{
unsigned char on = 1;
/* prepare settings for RAW socket */
socket_address.sll_family = PF_PACKET; /* RAW communication */
socket_address.sll_protocol = htons(ETH_P_IP); /* protocol above the ethernet layer */
socket_address.sll_ifindex = interface.ifr_ifindex; /* set index of the network device */
socket_address.sll_pkttype = PACKET_OTHERHOST; /* target host is another host */
/* initialize RAW socket */
if ((sock = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL))) == -1) {
fprintf(stderr, "[Error] Couldn't open RAW socket.\n");
perror("socket()");
return 1;
}
/* bind the socket to the interface */
if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, &interface, sizeof(struct ifreq)) == -1) {
fprintf(stderr, "[Error] Couldn't bind the socket to the interface.\n");
perror("setsockopt()");
return 1;
}
return 0;
}
/**
* Close socket. Should be called only once on program shutdown.
*
* @return 0 for success
* @return 1 for failure
*/
int transmission_quit(void)
{
/* close the socket */
if (close(sock)) {
fprintf(stderr, "[Error] Couldn't close the transmission socket.\n");
perror("close()");
return 1;
} else {
return 0;
}
}
/**
* Send raw packet -- not doing any modifications to it.
*
* @param data Raw packet data, including ethernet header
* @param length Length of the whole packet in bytes
*
* @return 0 for success
* @return 1 for failure
*/
int transmit(unsigned char *data, unsigned int length)
{
if (sendto(sock, data, length, 0, (struct sockaddr *) &socket_address, sizeof(struct sockaddr_ll)) != length) {
fprintf(stderr, "[Error] Couldn't send a RAW packet.\n");
perror("sendto()");
return 1;
}
return 0;
}

28
src/transmitter.h Normal file
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@ -0,0 +1,28 @@
/*
* WrapSix
* 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
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef TRANSMITTER_H
#define TRANSMITTER_H
#include "ipv4.h"
int transmission_init(void);
int transmission_quit(void);
int transmit(unsigned char *data, unsigned int length);
#endif /* TRANSMITTER_H */

14
src/wrapper.c
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@ -1,6 +1,6 @@
/*
* WrapSix
* Copyright (C) 2008-2011 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
@ -33,12 +33,14 @@
#include "ipv4.h"
#include "ipv6.h"
#include "nat.h"
#include "transmitter.h"
#include "wrapper.h"
#define INTERFACE "eth0"
#define BUFFER_SIZE 65536
#define PREFIX "::"
struct ifreq interface;
struct s_ipv6_addr ndp_multicast_addr;
struct s_ipv6_addr wrapsix_ipv6_prefix;
@ -46,7 +48,6 @@ int process(char *packet);
int main(int argc, char **argv)
{
struct ifreq interface;
struct packet_mreq pmr;
struct sockaddr_ll addr;
@ -85,6 +86,12 @@ int main(int argc, char **argv)
/* compute binary IPv6 address of WrapSix prefix */
inet_pton(AF_INET6, PREFIX, &wrapsix_ipv6_prefix);
/* initiate sending socket */
if (transmission_init()) {
fprintf(stderr, "[Error] Unable to initiate sending socket\n");
return 1;
}
/* initiate NAT tables */
nat_init();
@ -103,6 +110,9 @@ int main(int argc, char **argv)
}
/* clean-up */
/* close sending socket */
transmission_quit();
/* empty NAT tables */
nat_quit();

3
src/wrapper.h
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@ -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
@ -22,6 +22,7 @@
#include "ipv4.h"
#include "ipv6.h"
extern struct ifreq interface;
extern struct s_ipv6_addr ndp_multicast_addr;
extern struct s_ipv6_addr wrapsix_ipv6_prefix;