[PATCH iproute2 v1] iproute2: show counter of carrier on<->off transitions

[PATCH iproute2 v1] iproute2: show counter of carrier on<->off transitions

[David Decotigny]

This patch allows to display the current counter of carrier on<->off
transitions (IFLA_CARRIER_CHANGES, see kernel commit "expose number of
carrier on/off changes"):

  ip -s -s link show dev eth0
  ...
  2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 etc.
    link/ether ............ brd ff:ff:ff:ff:ff:ff
    RX: bytes  packets  errors  dropped overrun mcast
    134705     758      0       0       0       0
    RX errors: length  crc     frame   fifo    missed
               0        0       0       0       0
    TX: bytes  packets  errors  dropped carrier collsns
    77374      731      0       0       0       0
    TX errors: aborted fifo    window  heartbeat
               0        0       0       0
    link: carrier_changes 4

Tested:
  - kernel with patch "net-sysfs: expose number of carrier on/off
    changes": see above
  - kernel wthout the patch: line "link:" not displayed (as expected)

Signed-off-by: David Decotigny <decot@googlers.com>
---
 include/linux/if_link.h | 1 +
 ip/ipaddress.c          | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/include/linux/if_link.h b/include/linux/if_link.h
index f08505c..84fca1e 100644
--- a/include/linux/if_link.h
+++ b/include/linux/if_link.h
@@ -144,6 +144,7 @@ enum {
 	IFLA_NUM_RX_QUEUES,
 	IFLA_CARRIER,
 	IFLA_PHYS_PORT_ID,
+	IFLA_CARRIER_CHANGES,
 	__IFLA_MAX
 };
 
diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index 14d1720..78b80ee 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -527,6 +527,11 @@ int print_linkinfo(const struct sockaddr_nl *who,
 			print_link_stats(fp, RTA_DATA(tb[IFLA_STATS]));
 	}
 
+	if (do_link && (show_stats > 1) && tb[IFLA_CARRIER_CHANGES]) {
+		fprintf(fp, "%s    link: carrier_changes %u", _SL_,
+			*(int*)RTA_DATA(tb[IFLA_CARRIER_CHANGES]));
+	}
+
 	if (do_link && tb[IFLA_VFINFO_LIST] && tb[IFLA_NUM_VF]) {
 		struct rtattr *i, *vflist = tb[IFLA_VFINFO_LIST];
 		int rem = RTA_PAYLOAD(vflist);
-- 
1.9.1.423.g4596e3a

Re: [PATCH iproute2 v1] iproute2: show counter of carrier on<->off transitions

[Stephen Hemminger]

On Wed,  2 Apr 2014 09:19:00 -0700
David Decotigny <decot@googlers.com> wrote:

> This patch allows to display the current counter of carrier on<->off
> transitions (IFLA_CARRIER_CHANGES, see kernel commit "expose number of
> carrier on/off changes"):
> 
>   ip -s -s link show dev eth0
>   ...
>   2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 etc.
>     link/ether ............ brd ff:ff:ff:ff:ff:ff
>     RX: bytes  packets  errors  dropped overrun mcast
>     134705     758      0       0       0       0
>     RX errors: length  crc     frame   fifo    missed
>                0        0       0       0       0
>     TX: bytes  packets  errors  dropped carrier collsns
>     77374      731      0       0       0       0
>     TX errors: aborted fifo    window  heartbeat
>                0        0       0       0
>     link: carrier_changes 4
> 

I wonder if putting it under TX errors would make sense.
This is where Juniper classifies the error, and it would also
fit on same line, avoiding adding more clutter.


   2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 etc.
     link/ether ............ brd ff:ff:ff:ff:ff:ff
     RX: bytes  packets  errors  dropped overrun mcast
     134705     758      0       0       0       0
     RX errors: length  crc     frame   fifo    missed
                0        0       0       0       0
     TX: bytes  packets  errors  dropped carrier collsns
     77374      731      0       0       0       0
     TX errors: aborted fifo    window  heartbeat transition
                0        0       0       0        4

The risk is break some screen scraping script, but that doesn't
seem to be that big an issue for adding one column.

The columns also need some re-aligning here but that is different
correctness issue.