[EXT] Re: [PATCH v2 2/3] graph: pcap capture for graph nodes

[Stephen Hemminger]

On Thu, 12 Jan 2023 09:57:50 +0000
Amit Prakash Shukla <amitprakashs at marvell.com> wrote:

> Hi Stephen,
> 
> > -----Original Message-----
> > From: Stephen Hemminger <stephen at networkplumber.org>
> > Sent: Wednesday, January 11, 2023 9:37 PM
> > To: Amit Prakash Shukla <amitprakashs at marvell.com>
> > Cc: Jerin Jacob Kollanukkaran <jerinj at marvell.com>; Kiran Kumar
> > Kokkilagadda <kirankumark at marvell.com>; Nithin Kumar Dabilpuram
> > <ndabilpuram at marvell.com>; dev at dpdk.org
> > Subject: [EXT] Re: [PATCH v2 2/3] graph: pcap capture for graph nodes
> > 
> > External Email
> > 
> > ----------------------------------------------------------------------
> > On Wed, 11 Jan 2023 14:23:41 +0530
> > Amit Prakash Shukla <amitprakashs at marvell.com> wrote:
> >   
> > > +
> > > +#define PCAP_DUMP_DATA(dbuf, buf_size, cur_len, sbuf, len)                   \
> > > +do {                                                                         \
> > > +	if ((cur_len + len) >= buf_size)                                     \
> > > +		break;                                                       \
> > > +	rte_memcpy(dbuf + cur_len, sbuf, len);                               \
> > > +	cur_len += len;                                                      \
> > > +} while (0)
> > > +  
> > 
> > Why do you need this to be a macro.
> > Macro's are evil, have side effects and hide code.  
> 
> I had added macro for future, if lot of custom data is to be added to pcapng. Anyways I will remove it
> in next version of patch.

One other option is to add a new custom block type or options in pcapng.
Keep comment as a string, since that is what wireshark etc no how to handle.
Also, packet id data might be useful for graph.


https://pcapng.github.io/pcapng/draft-tuexen-opsawg-pcapng.html