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Work on TAP interfaces to work around injection issues on freebsd gif…
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… devices.
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John E committed Jun 17, 2012
1 parent ac42e30 commit c1704ac
Showing 1 changed file with 67 additions and 14 deletions.
81 changes: 67 additions & 14 deletions synfrag.c
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Expand Up @@ -38,6 +38,7 @@
#include <netinet/in_systm.h>
#include <ifaddrs.h>
#include <net/if_dl.h>
#include <net/if_tap.h>
#endif

#ifdef __linux
Expand Down Expand Up @@ -126,7 +127,7 @@ enum TEST_TYPE test_indexes[] = {
0
};

char *test_names[] = {
const char *test_names[] = {
"v4-tcp",
"v4-frag-tcp",
"v4-frag-icmp",
Expand All @@ -145,6 +146,9 @@ char *test_names[] = {
NULL
};

/* Globals */
char *tapname;
int tapfd = -1;
pcap_t *pcap;
pid_t listener_pid;
int pfd[2];
Expand Down Expand Up @@ -261,7 +265,11 @@ void synfrag_send( void *packet, int len )
printf( "Sending packet %u:\n\n", packets_sent++ );
print_a_packet( packet, len, 0 );
putchar( '\n' );
if ( pcap_inject( pcap, packet, len ) != len ) errx( 1, "pcap_inject failed: %s", pcap_geterr( pcap ) );
if ( tapfd >= 0 ) {
if ( write( tapfd, packet, len ) != len ) err( 1, "tap write failed" );
} else {
if ( pcap_inject( pcap, packet, len ) != len ) errx( 1, "pcap_inject failed: %s", pcap_geterr( pcap ) );
}
}

void print_ethh( struct ether_header *ethh )
Expand Down Expand Up @@ -432,7 +440,7 @@ char *print_a_packet( char *packet_data, int len, unsigned short wanted_type )
}
print_iph( iph );
if ( ( ntohs( iph->ip_off ) & 0x1FFF ) || ntohs( iph->ip_off ) & ( 1 << IP_FLAGS_OFFSET ) ) {
printf( "(Fragment)\n" );
printf( "[ Not parsing data fragment. ]\n" );
found_type = -1;
found_header = NULL;
} else if ( iph->ip_p == IPPROTO_TCP ) {
Expand Down Expand Up @@ -1208,7 +1216,7 @@ int harvest_pcap_listener( char **packet_buf ) {

void print_test_types( void )
{
char *test;
const char *test;
int x = 0;

fprintf( stderr, "Available test types:\n\n" );
Expand Down Expand Up @@ -1262,15 +1270,16 @@ enum TEST_TYPE parse_args(
unsigned short *dstport,
char **dstmac,
char **interface,
char **test_name,
const char **test_name,
long *timeout,
int *replay
int *replay,
int *do_tap
) {
int x = 0;
int option_index = 0;
int c, tmpport;
long tmptime;
char *possible_match;
const char *possible_match;
enum TEST_TYPE test_type = 0;
static struct option long_options[] = {
{"srcip", required_argument, 0, 0},
Expand All @@ -1283,14 +1292,15 @@ enum TEST_TYPE parse_args(
{"help", no_argument, 0, 0},
{"timeout", required_argument, 0, 0},
{"replay", no_argument, 0, 0},
{"tap", no_argument, 0, 0},
{0, 0, 0, 0}
};

if ( argc < 2 ) exit_with_usage();

*srcip = *dstip = *dstmac = *interface = NULL;
*srcport = -1;
*dstport = *replay = 0;
*dstport = *replay = *do_tap = 0;

while ( 1 ) {
c = getopt_long(argc, argv, "h", long_options, &option_index);
Expand Down Expand Up @@ -1329,6 +1339,9 @@ enum TEST_TYPE parse_args(
} else if ( strcmp( long_options[option_index].name, "replay" ) == 0 ) {
*replay = 1;

} else if ( strcmp( long_options[option_index].name, "tap" ) == 0 ) {
*do_tap = 1;

} else if ( strcmp( long_options[option_index].name, "test" ) == 0 ) {
while ( ( possible_match = test_names[x] ) ) {
if ( strcmp( optarg, possible_match ) == 0 ) {
Expand All @@ -1345,10 +1358,10 @@ enum TEST_TYPE parse_args(

if ( !*srcip ) errx( 1, "Missing srcip" );
if ( !*dstip ) errx( 1, "Missing dstip" );
if ( !*dstmac ) errx( 1, "Missing dstmac" );
if ( !*do_tap && !*dstmac ) errx( 1, "Missing dstmac" );
if ( !*interface ) errx( 1, "Missing interface" );
if ( !test_type ) {
fprintf( stderr, "Missing or invalid test type.\n" );
fprintf( stderr, "Missing or invalid test type\n" );
print_test_types();
exit( 1 );
}
Expand All @@ -1360,6 +1373,17 @@ enum TEST_TYPE parse_args(
return test_type;
}

void tap_cleanup( void )
{
struct ifreq ifr;
int s = socket( PF_INET, SOCK_DGRAM, 0 );
if ( s < 0 ) err( 1, "socket failed, unable to destroy tap interface %s", tapname );
memset( &ifr, 0, sizeof( struct ifreq ) );
strncpy( ifr.ifr_name, tapname, sizeof( ifr.ifr_name ) );
ioctl( s, SIOCIFDESTROY, &ifr );
close( s );
}

int main( int argc, char **argv )
{
char pcaperr[PCAP_ERRBUF_SIZE];
Expand All @@ -1375,11 +1399,12 @@ int main( int argc, char **argv )
uint16_t srcport;
uint32_t isn = htonl( rand() );
char *packet_buf;
char *test_name;
const char *test_name;
long receive_timeout = DEFAULT_TIMEOUT_SECONDS;
int replay;
int do_tap;

test_type = parse_args( argc, argv, &srcip, &dstip, &srcport_param, &dstport, &dstmac, &interface, &test_name, &receive_timeout, &replay );
test_type = parse_args( argc, argv, &srcip, &dstip, &srcport_param, &dstport, &dstmac, &interface, &test_name, &receive_timeout, &replay, &do_tap );
srand( getpid() );

if ( srcport_param == -1 ) {
Expand All @@ -1397,8 +1422,36 @@ int main( int argc, char **argv )
if ( pcap_datalink( pcap ) != DLT_EN10MB )
errx( 1, "non-ethernet interface specified." );

if ( ( srcmac = get_interface_mac( interface ) ) == NULL )
errx( 1, "Failed to get MAC address for %s", interface );
if ( do_tap ) {
#ifndef __FreeBSD__
err( 1, "Tap mode not supported on this OS." );
#else
struct ifreq ifr;
int s;
tapfd = open( "/dev/tap", O_RDWR );
if ( tapfd < 0 ) err( 1, "tap open" );
ioctl( tapfd, TAPGIFNAME, &ifr );
srcmac = get_interface_mac( ifr.ifr_name );
dstmac = strdup( srcmac );
if ( dstmac == NULL ) err( 1, "strdup" );
tapname = strdup( ifr.ifr_name );

printf( "Allocated tap interface %s for transmission.\n", tapname );

s = socket( PF_INET, SOCK_DGRAM, 0 );
if ( s < 0 ) err( 1, "socket open" );
ioctl( s, SIOCGIFFLAGS, &ifr );
strncpy( ifr.ifr_name, tapname, sizeof( ifr.ifr_name ) );
ifr.ifr_flags |= IFF_UP;
ioctl( s, SIOCSIFFLAGS, &ifr );
/* Pick a different src mac from the one on the interface itself. */
srcmac[16]++;
atexit( tap_cleanup );
#endif
} else {
if ( ( srcmac = get_interface_mac( interface ) ) == NULL )
errx( 1, "Failed to get MAC address for %s", interface );
}

if ( replay ) {
if ( !get_isn_for_replay( interface, srcip, dstip, dstport, test_type, &isn, &srcport ) ) {
Expand Down

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