tcpdump mailing list archives

Re: Request for a DLT value (for nflog)


From: Guy Harris <guy () alum mit edu>
Date: Mon, 20 Jun 2011 11:46:50 -0700


On Jun 20, 2011, at 3:21 AM, Jakub Zawadzki wrote:

After which follow any numbers of TLVs.

(Structure From <linux/netfilter/nfnetlink_compat.h> header)

struct nfattr {
 uint16_t nfa_len;      /** length, including 4 bytes of header, host-order **/
 uint16_t nfa_type;  /* we use 15 bits for the type, and the highest
                      *bit to indicate whether the payload is nested */
                     /** type, host-order */

 /** uint8_t nfa_data[nfattr.nfa_len-4] **/
};

Known types are defined in enum nfulnl_attr_type (<linux/netfilter/nfnetlink_log.h>)

Some of these includes:
 - NFULA_PAYLOAD=0x9 /* opaque data payload */
   /** nfgen_family payload **/
 - NFULA_PREFIX=0xa /* string prefix */
   /** prefix (from --nflog-prefix) NUL-terminated */
 - NFULA_UID=0xb  /* user id of socket */
    /** 4B in BE */
 - NFULA_GID=0xe  /* group id of socket */
    /** 4B in BE */
 ...

And is there any packet data in there?  For example, is that what's in NFULA_PAYLOAD TLVs?-
This is the tcpdump-workers list.
Visit https://cod.sandelman.ca/ to unsubscribe.


Current thread: