source: libpacketdump/ip_33.c @ 0a22046

/* DCCP */
#include <stdio.h>
#include <inttypes.h>
#include <dlfcn.h>
#include "libpacketdump.h"
#include <netinet/tcp.h>
#include <netinet/in.h>

#define STRUCT dccp

#define SAFE(x) \
        ((unsigned int)len>=((char*)&STRUCT->x-(char*)STRUCT+sizeof(STRUCT->x))) 
#define DISPLAY_EXP(x,fmt,exp) \
        if (SAFE(x)) \
                printf(fmt,exp); \
        else \
                return; 

#define DISPLAY(x,fmt) DISPLAY_EXP(x,fmt,STRUCT->x)

#define DISPLAYS(x,fmt) DISPLAY_EXP(x,fmt,htons(STRUCT->x))
#define DISPLAYL(x,fmt) DISPLAY_EXP(x,fmt,htonl(STRUCT->x))
#define DISPLAYIP(x,fmt) DISPLAY_EXP(x,fmt,inet_ntoa(*(struct in_addr*)&STRUCT->x))

struct dccphdr {
        uint16_t source;
        uint16_t dest;
        uint8_t type:4;
        uint8_t ccval:4;
        uint32_t seq:24;
        uint8_t doff;
        uint8_t ndp:4;
        uint8_t cslen:4;
        uint16_t check;
};

static char *dccp_types[]={
        "DCCP-Request packet",
        "DCCP-Response packet",
        "DCCP-Data packet",
        "DCCP-Ack packet",
        "DCCP-DataAck packet",
        "DCCP-CloseReq packet",
        "DCCP-Close packet",
        "DCCP-Reset packet",
        "DCCP-Move packet",
        };

int get_next_option(unsigned char **ptr,int *len,
                        unsigned char *type,
                        unsigned char *optlen,
                        unsigned char **data)
{
        if (*len<=0)
                return 0;
        *type=**ptr;
        switch(*type) {
                case 0:
                        return 0;
                case 1:
                        (*ptr)++;
                        (*len)--;
                        return 1;
                default:
                        *optlen = *(*ptr+1);
                        (*len)-=*optlen;
                        (*data)=(*ptr+2);
                        (*ptr)+=*optlen;
                        if (*len<0)
                                return 0;
                        return 1;
        }
}

void decode(int link_type,char *packet,int len)
{
        struct dccphdr *dccp = (struct dccphdr*)packet;
        DISPLAYS(source," DCCP: Source %i");
        DISPLAYS(dest," Dest %i");
        if (len>4) {
                printf("\n DCCP: Type %i",dccp->type);
                if (dccp->type<sizeof(dccp_types)) {
                        printf(" (%s)\n",dccp_types[dccp->type]);
                } else {
                        printf(" (Unknown)\n");
                }
                printf(" DCCP: CcVal %i\n",dccp->ccval);
        }
        else  {
                printf("\n"); 
                return;
        }
        if (len>7)
                printf(" DCCP: Seq %u\n",dccp->seq); // htonwhat?
        else
                return;
        DISPLAY(doff," DCCP: Dataoff: %i\n");
        if (len>9)
                printf(" DCCP: NDP %i CsLen: %i\n",dccp->ndp,dccp->cslen);
        else {
                return;
        }
        DISPLAY(check," DCCP: Checksum: %i\n");
        if (htons(dccp->source) < htons(dccp->dest)) 
                decode_next(packet+dccp->doff*4,len-dccp->doff*4,"dccp",htons(dccp->source));
        else
                decode_next(packet+dccp->doff*4,len-dccp->doff*4,"dccp",htons(dccp->dest));
        return;
}