int packetOkDNA(unsigned char *packet,int len,unsigned char *transaction_id,
int recvttl,
struct sockaddr *recvaddr, size_t recvaddrlen, int parseP)
{
/* Make sure that the packet is meant for us, and is not mal-formed */
int version;
int cipher;
int length;
int payloadRotation;
version=(packet[2]<<8)|packet[3];
length=(packet[4]<<8)|packet[5];
cipher=(packet[6]<<8)|packet[7];
if (version!=1) return WHY("Unknown packet format version");
if (cipher!=0) return WHY("Unknown packet cipher");
if (length!=len) return WHY("Packet length incorrect");
if (cipher)
if (packetDecipher(packet,len,cipher))
return WHY("Could not decipher packet");
/* Make sure the transaction ID matches */
if (transaction_id)
{
int i;
for(i=0;i<TRANSID_SIZE;i++)
if (packet[OFS_TRANSIDFIELD+i]!=transaction_id[i])
return WHY("transaction ID mismatch");
}
/* Unrotate the payload */
payloadRotation=packet[OFS_ROTATIONFIELD];
{
unsigned char temp[256];
bcopy(&packet[len-payloadRotation],&temp[0],payloadRotation);
bcopy(&packet[HEADERFIELDS_LEN],&packet[HEADERFIELDS_LEN+payloadRotation],
len-(HEADERFIELDS_LEN)-payloadRotation);
bcopy(&temp[0],&packet[HEADERFIELDS_LEN],payloadRotation);
}
if (debug&DEBUG_PACKETFORMATS) {
DEBUG("Packet passes sanity checks and is ready for decoding");
dump("unrotated packet",packet,len);
}
if (parseP) return process_packet(packet,len,recvttl,recvaddr,recvaddrlen); else return 0;
}
int packetOk(unsigned char *packet,int len,unsigned char *transaction_id)
{
/* Make sure that the packet is meant for us, and is not mal-formed */
int version;
int cipher;
int length;
int payloadRotation;
if (len<HEADERFIELDS_LEN) return setReason("Packet is too short");
if (packet[0]!=0x41||packet[1]!=0x10) return setReason("Packet has incorrect magic value");
version=(packet[2]<<8)|packet[3];
length=(packet[4]<<8)|packet[5];
cipher=(packet[6]<<8)|packet[7];
if (version!=1) return setReason("Unknown packet format version");
if (cipher!=0) return setReason("Unknown packet cipher");
if (length!=len) return setReason("Packet length incorrect");
if (cipher)
if (packetDecipher(packet,len,cipher))
return setReason("Could not decipher packet");
/* Make sure the transaction ID matches */
if (transaction_id)
{
int i;
for(i=0;i<TRANSID_SIZE;i++)
if (packet[OFS_TRANSIDFIELD+i]!=transaction_id[i])
return setReason("transaction ID mismatch");
}
/* Unrotate the payload */
payloadRotation=packet[OFS_ROTATIONFIELD];
{
unsigned char temp[256];
bcopy(&packet[len-payloadRotation],&temp[0],payloadRotation);
bcopy(&packet[HEADERFIELDS_LEN],&packet[HEADERFIELDS_LEN+payloadRotation],
len-(HEADERFIELDS_LEN)-payloadRotation);
bcopy(&temp[0],&packet[HEADERFIELDS_LEN],payloadRotation);
}
if (debug>1) fprintf(stderr,"Packet passes sanity checks and is ready for decoding.\n");
if (debug>2) dump("unrotated packet",packet,len);
return 0;
}
