[PATCH] Add idrop report to netstat

[Attilio Rao]

2009/11/17 Pyun YongHyeon <pyunyh at gmail.com>:
> On Mon, Nov 16, 2009 at 11:04:20PM +0100, Attilio Rao wrote:
>> 2009/11/16 Pyun YongHyeon <pyunyh at gmail.com>:
>> > On Mon, Nov 16, 2009 at 04:15:09PM +0100, Attilio Rao wrote:
>> >> [Please CC me as I'm not subscribed to -net@]
>> >>
>> >> This patch allows to show the informations about packets droped on
>> >> input for interfaces on netstat:
>> >> http://www.freebsd.org/~attilio/Sandvine/STABLE_8/idrops/idrops.diff
>> >>
>> >> This patch as been contributed back from Sandvine Incorporated.
>> >> Comments, reviews and testing are welcome.
>> >>
>> >
>> > Doesn't -d of netstat(1) show the same information?
>>
>> Am I wrong or "-d" prints the drops on the output path?
>> The patch provides information on the input drops.
>>
>
> struct if_data {
>        /* generic interface information */
>        u_char  ifi_type;               /* ethernet, tokenring, etc */
>        u_char  ifi_physical;           /* e.g., AUI, Thinnet, 10base-T, etc */
> [...]
>        u_long  ifi_iqdrops;            /* dropped on input, this interface */
>                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
>        u_long  ifi_noproto;            /* destined for unsupported protocol */
>        u_long  ifi_hwassist;           /* HW offload capabilities, see IFCAP */
>        time_t  ifi_epoch;              /* uptime at attach or stat reset */
>        struct  timeval ifi_lastchange; /* time of last administrative change */
> };

Err, but dflag does print out if_snd.ifq_drops. Infact:

@if.c:sidewaysintpr()

[...]
                if (!first) {
                        show_stat("lu", 10, ifnet.if_ipackets - ip->ift_ip, 1);
                        show_stat("lu", 5, ifnet.if_ierrors - ip->ift_ie, 1);
                        show_stat("lu", 10, ifnet.if_ibytes - ip->ift_ib, 1);
                        show_stat("lu", 10, ifnet.if_opackets - ip->ift_op, 1);
                        show_stat("lu", 5, ifnet.if_oerrors - ip->ift_oe, 1);
                        show_stat("lu", 10, ifnet.if_obytes - ip->ift_ob, 1);
                        show_stat("NRSlu", 5,
                            ifnet.if_collisions - ip->ift_co, 1);
                        if (dflag)
                                show_stat("LSu", 5,
                                    ifnet.if_snd.ifq_drops - ip->ift_dr, 1);
                }
[...]
               if (!first) {
                        show_stat("lu", 10, sum->ift_ip - total->ift_ip, 1);
                        show_stat("lu", 5, sum->ift_ie - total->ift_ie, 1);
                        show_stat("lu", 10, sum->ift_ib - total->ift_ib, 1);
                        show_stat("lu", 10, sum->ift_op - total->ift_op, 1);
                        show_stat("lu", 5, sum->ift_oe - total->ift_oe, 1);
                        show_stat("lu", 10, sum->ift_ob - total->ift_ob, 1);
                        show_stat("NRSlu", 5, sum->ift_co - total->ift_co, 1);
                        if (dflag)
                                show_stat("LSu", 5,
                                    sum->ift_dr - total->ift_dr, 1);
                }


Which is defined in sys/net/if_var.h as:

struct ifnet {
        void    *if_softc;              /* pointer to driver state */
        void    *if_l2com;              /* pointer to protocol bits */
        struct vnet *if_vnet;           /* pointer to network stack instance */
[...]
        int     if_drv_flags;           /* driver-managed status flags */
        struct  ifaltq if_snd;          /* output queue (includes altq) */
        const u_int8_t *if_broadcastaddr; /* linklevel broadcast bytestring */
[...]
};

Thanks,
Attilio


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