From: Jakub Kicinski <jakub.kicinski@netronome•com>
To: Stephen Hemminger <stephen@networkplumber•org>
Cc: alexei.starovoitov@gmail•com, daniel@iogearbox•net,
dsahern@gmail•com, netdev@vger•kernel.org,
oss-drivers@netronome•com
Subject: Re: [PATCH iproute2-next] iplink: add support for reporting multiple XDP programs
Date: Fri, 13 Jul 2018 14:20:37 -0700 [thread overview]
Message-ID: <20180713142037.503b7b01@cakuba.lan> (raw)
In-Reply-To: <20180713135941.3791c3ff@xeon-e3>
On Fri, 13 Jul 2018 13:59:41 -0700, Stephen Hemminger wrote:
> On Fri, 13 Jul 2018 13:43:59 -0700
> Jakub Kicinski <jakub.kicinski@netronome•com> wrote:
>
> >
> > +static void xdp_dump_prog_one(FILE *fp, struct rtattr *tb[IFLA_XDP_MAX + 1],
> > + __u32 attr, bool link, bool details, char *pfx)
> > +{
> > + __u32 prog_id;
> > +
> > + if (!tb[attr])
> > + return;
> > +
> > + prog_id = rta_getattr_u32(tb[attr]);
> > + if (!details) {
> > + if (prog_id && !link && attr == IFLA_XDP_PROG_ID)
> > + fprintf(fp, "/id:%u", prog_id);
> > + return;
> > + }
> > +
> > + if (prog_id) {
> > + fprintf(fp, "%s prog/xdp%s ", _SL_, pfx);
> > + bpf_dump_prog_info(fp, prog_id);
> > + }
>
> Maybe const char *pfx.
Will do! Looking again at this code, I think I will also do this:
diff --git a/ip/iplink_xdp.c b/ip/iplink_xdp.c
index 0328bc01a981..68629834cc00 100644
--- a/ip/iplink_xdp.c
+++ b/ip/iplink_xdp.c
@@ -121,6 +121,12 @@ static void xdp_dump_json(struct rtattr *tb[IFLA_XDP_MAX + 1])
xdp_dump_json_one(tb, IFLA_XDP_SKB_PROG_ID, XDP_ATTACHED_SKB);
xdp_dump_json_one(tb, IFLA_XDP_DRV_PROG_ID, XDP_ATTACHED_DRV);
xdp_dump_json_one(tb, IFLA_XDP_HW_PROG_ID, XDP_ATTACHED_HW);
+ /* Older kernel - use IFLA_XDP_PROG_ID */
+ if (tb[IFLA_XDP_PROG_ID] &&
+ !(tb[IFLA_XDP_ATTACHED_SKB] ||
+ tb[IFLA_XDP_ATTACHED_DRV] ||
+ tb[IFLA_XDP_ATTACHED_HW]))
+ xdp_dump_json_one(tb, IFLA_XDP_PROG_ID, mode);
close_json_array(PRINT_JSON, NULL);
close_json_object();
So that on older kernels we will still be able to depend on the
contents of the "attached" array, even if kernel does not know to
report program per-mode, yet.
> I prefer to not use "printf(fp," and use print_string(PRINT_FP, NULL, "%s", ...)
> because otherwise you end up mixing strings and json format output in the
> same result.
>
> You should be able to do
> tc -j ...
> and always get valid JSON output.
>
> One quick way to test json validation is to pipe it into python:
> tc -j ... | python -mjson.tool
Note that XDP has separate print functions for plain text and JSON, and
the flow gets separated early on:
mode = rta_getattr_u8(tb[IFLA_XDP_ATTACHED]);
if (mode == XDP_ATTACHED_NONE)
return;
else if (is_json_context())
return details ? (void)0 : xdp_dump_json(tb);
... non-JSON handling follows...
The use of fprintfs is therefore okay. Do you have a preference for
using the wrapper, even if fprintf is safe? It's brevity vs
consistency, I guess. We'd need a separate patch for that, 'cause I'm
not touching all the fprintfs in the file, anyway.
next prev parent reply other threads:[~2018-07-13 21:37 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-13 20:43 [PATCH iproute2-next] iplink: add support for reporting multiple XDP programs Jakub Kicinski
2018-07-13 20:59 ` Stephen Hemminger
2018-07-13 21:20 ` Jakub Kicinski [this message]
2018-07-13 22:23 ` Stephen Hemminger
2018-07-13 22:59 ` Jakub Kicinski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180713142037.503b7b01@cakuba.lan \
--to=jakub.kicinski@netronome$(echo .)com \
--cc=alexei.starovoitov@gmail$(echo .)com \
--cc=daniel@iogearbox$(echo .)net \
--cc=dsahern@gmail$(echo .)com \
--cc=netdev@vger$(echo .)kernel.org \
--cc=oss-drivers@netronome$(echo .)com \
--cc=stephen@networkplumber$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox