Messages in this thread | | | Date | Thu, 27 Jan 2022 18:02:56 +0200 | From | Ido Schimmel <> | Subject | Re: [PATCH v3 net-next] net: drop_monitor: support drop reason |
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On Thu, Jan 27, 2022 at 08:53:04AM -0700, David Ahern wrote: > On 1/26/22 8:33 PM, menglong8.dong@gmail.com wrote: > > From: Menglong Dong <imagedong@tencent.com> > > > > In the commit c504e5c2f964 ("net: skb: introduce kfree_skb_reason()") > > drop reason is introduced to the tracepoint of kfree_skb. Therefore, > > drop_monitor is able to report the drop reason to users by netlink. > > > > For now, the number of drop reason is passed to users ( seems it's > > a little troublesome to pass the drop reason as string ). Therefore, > > users can do some customized description of the reason. > > > > Signed-off-by: Menglong Dong <imagedong@tencent.com> > > --- > > v3: > > - referring to cb->reason and cb->pc directly in > > net_dm_packet_report_fill() > > > > v2: > > - get a pointer to struct net_dm_skb_cb instead of local var for > > each field > > --- > > include/uapi/linux/net_dropmon.h | 1 + > > net/core/drop_monitor.c | 16 ++++++++++++---- > > 2 files changed, 13 insertions(+), 4 deletions(-) > > > > diff --git a/include/uapi/linux/net_dropmon.h b/include/uapi/linux/net_dropmon.h > > index 66048cc5d7b3..b2815166dbc2 100644 > > --- a/include/uapi/linux/net_dropmon.h > > +++ b/include/uapi/linux/net_dropmon.h > > @@ -93,6 +93,7 @@ enum net_dm_attr { > > NET_DM_ATTR_SW_DROPS, /* flag */ > > NET_DM_ATTR_HW_DROPS, /* flag */ > > NET_DM_ATTR_FLOW_ACTION_COOKIE, /* binary */ > > + NET_DM_ATTR_REASON, /* u32 */ > > > > For userspace to properly convert reason from id to string, enum > skb_drop_reason needs to be moved from skbuff.h to a uapi file. > include/uapi/linux/net_dropmon.h seems like the best candidate to me. > Maybe others have a better idea.
I think the best option would be to convert it to a string in the kernel (or report both). Then you don't need to update user space tools such as the Wireshark dissector [1] and DropWatch every time a new reason is added.
[1] https://www.wireshark.org/docs/dfref/n/net_dm.html
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