Re: [PATCH iproute2-next 06/11] ipstats: Add a group "link"

[Petr Machata <petrm@nvidia.com>]

Ido Schimmel <idosch@idosch.org> writes:

> When I tested this on 5.15 / 5.16 everything was fine, but now I get:
>
> $ ip stats show dev lo group link
> 1: lo: group link
> Error: attribute payload too short
>
> Payload on 5.16:
>
> recvmsg(3, {msg_name={sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000}, msg_namelen=12, msg_iov=[{iov_base=[{nlmsg_len=224, nlmsg_type=RTM_NEWSTATS, nlmsg_flags=0, nlmsg_seq=1651407379, nlmsg_pid=330213}, {family=AF_UNSPEC, ifindex=if_nametoindex("lo"), filter_mask=1<<IFLA_STATS_UNSPEC}, [{nla_len=196, nla_type=IFLA_STATS_LINK_64}, {rx_packets=321113, tx_packets=321113, rx_bytes=322735996, tx_bytes=322735996, rx_errors=0, tx_errors=0, rx_dropped=0, tx_dropped=0, multicast=0, collisions=0, rx_length_errors=0, rx_over_errors=0, rx_crc_errors=0, rx_frame_errors=0, rx_fifo_errors=0, rx_missed_errors=0, tx_aborted_errors=0, tx_carrier_errors=0, tx_fifo_errors=0, tx_heartbeat_errors=0, tx_window_errors=0, rx_compressed=0, tx_compressed=0, rx_nohandler=0}]], iov_len=32768}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 224
> 1: lo: group link
> Error: attribute payload too short+++ exited with 22 +++
>
> Payload on net-next:
>
> recvmsg(3, {msg_name={sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000}, msg_namelen=12, msg_iov=[{iov_base=[{nlmsg_len=232, nlmsg_type=RTM_NEWSTATS, nlmsg_flags=0, nlmsg_seq=1651407411, nlmsg_pid=198}, {family=AF_UNSPEC, ifindex=if_nametoindex("lo"), filter_mask=1<<IFLA_STATS_UNSPEC}, [{nla_len=204, nla_type=IFLA_STATS_LINK_64}, {rx_packets=0, tx_packets=0, rx_bytes=0, tx_bytes=0, rx_errors=0, tx_errors=0, rx_dropped=0, tx_dropped=0, multicast=0, collisions=0, rx_length_errors=0, rx_over_errors=0, rx_crc_errors=0, rx_frame_errors=0, rx_fifo_errors=0, rx_missed_errors=0, tx_aborted_errors=0, tx_carrier_errors=0, tx_fifo_errors=0, tx_heartbeat_errors=0, tx_window_errors=0, rx_compressed=0, tx_compressed=0, rx_nohandler=0}]], iov_len=32768}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 232
> 1: lo: group link
>     RX:  bytes packets errors dropped  missed   mcast           
>              0       0      0       0       0       0 
>     TX:  bytes packets errors dropped carrier collsns           
>              0       0      0       0       0       0 
> +++ exited with 0 +++
>
> Note the difference in size of IFLA_STATS_LINK_64 which carries struct
> rtnl_link_stats64: 196 bytes vs. 204 bytes
>
> The 8 byte difference is most likely from the addition of
> rx_otherhost_dropped at the end:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=794c24e9921f32ded4422833a990ccf11dc3c00e
>
> I guess it worked for me because I didn't have this member in my copy of
> the uAPI file, but it's now in iproute2-next:
>
> https://git.kernel.org/pub/scm/network/iproute2/iproute2-next.git/commit/?id=bba95837524d09ee2f0efdf6350b83a985f4b2f8

Thanks, I'll send a fix.