lupine/hide-eid
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

packet: move some common code out of wrapper.c and util.c

Browse Source
This commit is contained in:
Nick Thomas
2013-08-06 14:34:53 +01:00
parent 94b451a1ac
commit 202b77bb57
6 changed files with 80 additions and 75 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
pass-1/Makefile
View File

@@ -9,7 +9,9 @@ all: wrapper unwrapper
rlocs.o: util.o
wrapper: util.o rlocs.o
packet.o: util.o
wrapper: util.o rlocs.o packet.o
clean:
rm -f wrapper unwrapper *.o

35
pass-1/packet.c Normal file
View File

@@ -0,0 +1,35 @@
#include "packet.h"
// shamelessly copied from:
// http://www.roman10.net/how-to-calculate-iptcpudp-checksumpart-2-implementation/
unsigned short compute_checksum(unsigned short *addr, unsigned int count) {
unsigned long sum = 0;
while (count > 1) {
sum += * addr++;
count -= 2;
}
//if any bytes left, pad the bytes and add
if(count > 0) {
sum += ((*addr)&htons(0xFF00));
}
//Fold sum to 16 bits: add carrier to result
while (sum>>16) {
sum = (sum & 0xffff) + (sum >> 16);
}
//one's complement
sum = ~sum;
return ((unsigned short)sum);
}
void compute_ip_checksum(struct iphdr* pkt)
{
pkt->check = 0x0000;
pkt->check = compute_checksum( (unsigned short*) pkt, pkt->ihl * 4 );
}

40
pass-1/packet.h Normal file
View File

@@ -0,0 +1,40 @@
#ifndef _PACKET_H_
#define _PACKET_H_
#include <arpa/inet.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
struct packet {
union {
#ifdef __USE_BSD
struct ip ip;
#else
struct iphdr ip;
#endif
struct ip6_hdr ip6;
} hdr;
char payload[IP_MAXPACKET]; /* payload is this - header size, but OK */
};
// wrapper.c expects this name
#define recv_pkt packet
// It's all our code that uses this. 12 is much more than we need to
// construct a wrapped packet at the moment.
//
// initial usage:
// 0 - wrapping ip header, including enc_size
// 1 - encrypted portion of payload, in scratch.
// 2 - unencrypted portion of payload, in recv_pkt
#define MAX_IOVS 12
struct rsp_data {
int count;
struct iovec iovs[MAX_IOVS];
unsigned char scratch[IP_MAXPACKET]; // somewhere easy to put results
};
void compute_ip_checksum( struct iphdr* pkt );
#endif

37
pass-1/util.c
View File

@@ -52,43 +52,6 @@ int create_tun( const char* name )
return fd;
}
// shamelessly copied from:
// http://www.roman10.net/how-to-calculate-iptcpudp-checksumpart-2-implementation/
unsigned short compute_checksum(unsigned short *addr, unsigned int count) {
unsigned long sum = 0;
while (count > 1) {
sum += * addr++;
count -= 2;
}
//if any bytes left, pad the bytes and add
if(count > 0) {
sum += ((*addr)&htons(0xFF00));
}
//Fold sum to 16 bits: add carrier to result
while (sum>>16) {
sum = (sum & 0xffff) + (sum >> 16);
}
//one's complement
sum = ~sum;
return ((unsigned short)sum);
}
void compute_ip_checksum(struct iphdr* pkt)
{
pkt->check = 0x0000;
pkt->check = compute_checksum( (unsigned short*) pkt, pkt->ihl * 4 );
}
int link_set_up( char *link_name, int state )
{
int fd = socket( PF_INET, SOCK_DGRAM, IPPROTO_IP );

2
pass-1/util.h
View File

@@ -14,8 +14,6 @@
void* xmalloc( size_t bytes );
int create_tun( const char* name );
void compute_ip_checksum( struct iphdr* pkt );
int link_set_up( char *link_name, int state );

37
pass-1/wrapper.c
View File

@@ -1,18 +1,11 @@
#include "util.h"
#include "rlocs.h"
// We use a TUN device right now so we don't have to care about layer 2 headers
// or complicated, hard scaling stuff. This isn't likely to scale very well.
#include <assert.h>
#include <unistd.h>
#include <errno.h>
#include <arpa/inet.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include "packet.h"
// We use writev() to send the packet, so we don't have to copy the
// unencrypted part.
@@ -25,32 +18,6 @@ typedef struct wrapper {
int same_if;
} wrapper;
struct recv_pkt {
union {
#ifdef __USE_BSD
struct ip ip;
#else
struct iphdr ip;
#endif
struct ip6_hdr ip6;
} hdr;
char payload[IP_MAXPACKET]; /* payload is this - header size, but OK */
};
// It's all our code that uses this. 12 is more than we probably need to
// construct a wrapped packet - just being careful.
//
// initial usage:
// 0 - wrapping ip header, including enc_size
// 1 - encrypted portion of payload, in scratch.
// 2 - unencrypted portion of payload, in recv_pkt
#define MAX_IOVS 12
struct rsp_data {
int count;
struct iovec iovs[MAX_IOVS];
unsigned char scratch[IP_MAXPACKET]; // somewhere easy to put results
};
int wrap_ipv4_packet(struct rlocs* reg, struct recv_pkt* pkt, struct rsp_data* out)
{
@@ -173,7 +140,7 @@ int wrap_ipv6_packet(struct rlocs *reg, struct recv_pkt* pkt, struct rsp_data* o
int main(int argc, char** argv)
{
wrapper wrap;
if ( argc < 4 ) {
warn( "Usage: %s <rloc database> <listen_ifname> <output_ifname>", argv[0] );
return 1;