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/* Decoder for PPP with HDLC frames */
#include <sys/types.h>
#include <netinet/in.h>
#include <stdio.h>
#include <inttypes.h>
#include <dlfcn.h>
#include "libtrace.h"
#include "libpacketdump.h"
typedef struct libtrace_hdlc_t {
uint8_t address; /** Always 0xff */
uint8_t control; /** Always 0x03 */
uint16_t protocol;
} libtrace_hdlc_t;
DLLEXPORT void decode(int link_type UNUSED,const char *packet,unsigned len)
{
libtrace_hdlc_t *frame = (libtrace_hdlc_t *)packet;
printf(" PPP:");
if (len >= 1)
printf(" Address: 0x%02x", frame->address);
else {
printf("[|Truncated]\n");
return;
}
if (len >= 2)
printf(" Control: 0x%02x", frame->control);
else {
printf("[|Truncated]\n");
return;
}
if (len >= 4) {
printf(" Protocol: 0x%04x\n", ntohs(frame->protocol));
/* PPP protocols do not match ethertypes, so we have to
* convert
*
* XXX develop decoders for PPP protocols so this can be
* done generically
*/
if (ntohs(frame->protocol) == 0x0021) {
decode_next(packet + 4, len - 4, "eth", 0x0800);
}
}
else {
printf("[|Truncated]\n");
return;
}
return;
}
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