hmm.. ok ,  in l2_learning.py code,  why did we 'match' msg with the parsed
packet??


        msg = of.ofp_flow_mod()

        msg.match = of.ofp_match.from_packet(packet, event.port)

I thought ofp_match() is used only for comparison . But the debug
above shows that, ofp_match() not only compares but also updates 'msg'
packet with details in the parsed packet . Is it so??


Cheers!
Durga



On Fri, Oct 25, 2013 at 5:34 AM, Murphy McCauley
<murphy.mccau...@gmail.com>wrote:

> I'm afraid I don't follow the issue.  Maybe you can post more code and try
> to further explain what you think is happening vs. what you think *should*
> be happening?
>
> -- Murphy
>
> On Oct 23, 2013, at 7:13 PM, durga <c.vijaya.du...@gmail.com> wrote:
>
> Hello All,
>
> Just needed a confirmation on my understanding about match statement, all
> the official resources mention as to matching/creating a match and the best
> way to create a match from an existing packet is as below.
> my_match = ofp_match.from_packet(packet, in_port)
>
> Now , as I debug , looks like match is actually used to  compare and
> update the new packet with the details provided in the original packet  and
> not just compare
>
> is this correct?
>
>
>
>
> DEBUG:l2_switching_v4:ofp_flow_mod
>   header:
>     version: 1
>     type:    14 (OFPT_FLOW_MOD)
>     length:  72
>     xid:     12
>   match:
>     wildcards:
> nw_tos|tp_dst|dl_dst|dl_src|in_port|dl_vlan_pcp|nw_proto|dl_vlan|tp_src|dl_type|nw_src(/0)|nw_dst(/0)
> (1110000010000011111111 = 3820ff)
>   cookie: 0
>   command: 0
>   idle_timeout: 0
>   hard_timeout: 0
>   priority: 32768
>   buffer_id: None
>   out_port: 65535
>   flags: 0
>   actions:
>
> *debug after ofp_flow_mod().match = ofp_match.from_packet(packet, in_port)
> *
>
> DEBUG:l2_switching_v4:ofp_flow_mod
>   header:
>     version: 1
>     type:    14 (OFPT_FLOW_MOD)
>     length:  80
>     xid:     12
>   match:
>     wildcards: nw_tos|tp_dst|tp_src (1000000000000011000000 = 2000c0)
>     in_port: 2
>     dl_src: 00:00:00:00:00:02
>     dl_dst: 00:00:00:00:00:01
>     dl_vlan: 65535
>     dl_vlan_pcp: 0
>     dl_type: 0x806
>     nw_proto: 2
>     nw_src: 10.0.0.2
>     nw_dst: 10.0.0.1
>   cookie: 0
>   command: 0
>   idle_timeout: 0
>   hard_timeout: 0
>   priority: 32768
>   buffer_id: None
>   out_port: 65535
>   flags: 0
>   actions:
>     type: 0
>     len: 8
>     port: 1
>     max_len: 65535
> Cheers!
> Durga
>
>
>

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