Re: [PATCH iproute2-next 2/3] q_netem: support delivering packets in delayed time slots

[David Ahern <dsahern@gmail.com>]

On 8/6/18 11:09 AM, Yousuk Seung wrote:
> diff --git a/tc/q_netem.c b/tc/q_netem.c
> index 9f9a9b3df255..f52a36b6c31c 100644
> --- a/tc/q_netem.c
> +++ b/tc/q_netem.c
> @@ -40,7 +40,10 @@ static void explain(void)
>  "                 [ loss gemodel PERCENT [R [1-H [1-K]]]\n" \
>  "                 [ ecn ]\n" \
>  "                 [ reorder PRECENT [CORRELATION] [ gap DISTANCE ]]\n" \
> -"                 [ rate RATE [PACKETOVERHEAD] [CELLSIZE] [CELLOVERHEAD]]\n");
> +"                 [ rate RATE [PACKETOVERHEAD] [CELLSIZE] [CELLOVERHEAD]]\n" \
> +"                 [ slot MIN_DELAY [MAX_DELAY] [packets MAX_PACKETS]" \
> +" [bytes MAX_BYTES]]\n" \
> +		);
>  }
>  
>  static void explain1(const char *arg)
> @@ -164,6 +167,7 @@ static int netem_parse_opt(struct qdisc_util *qu, int argc, char **argv,
>  	struct tc_netem_gimodel gimodel;
>  	struct tc_netem_gemodel gemodel;
>  	struct tc_netem_rate rate = {};
> +	struct tc_netem_slot slot = {};
>  	__s16 *dist_data = NULL;
>  	__u16 loss_type = NETEM_LOSS_UNSPEC;
>  	int present[__TCA_NETEM_MAX] = {};
> @@ -412,6 +416,44 @@ static int netem_parse_opt(struct qdisc_util *qu, int argc, char **argv,
>  					return -1;
>  				}
>  			}
> +		} else if (matches(*argv, "slot") == 0) {
> +			NEXT_ARG();
> +			present[TCA_NETEM_SLOT] = 1;
> +			if (get_time64(&slot.min_delay, *argv)) {
> +				explain1("slot min_delay");
> +				return -1;
> +			}
> +			if (NEXT_IS_NUMBER()) {
> +				NEXT_ARG();
> +				if (get_time64(&slot.max_delay, *argv)) {
> +					explain1("slot min_delay max_delay");
> +					return -1;
> +				}
> +			}
> +			if (slot.max_delay < slot.min_delay)

If max_delay is user specified, this should generate an error rather
than just overwriting the value.

> +				slot.max_delay = slot.min_delay;
> +			if (NEXT_ARG_OK() &&
> +			    matches(*(argv+1), "packets") == 0) {
> +				NEXT_ARG();
> +				if (!NEXT_ARG_OK() ||
> +				    get_s32(&slot.max_packets, *(argv+1), 0)) {
> +					explain1("slot packets");
> +					return -1;
> +				}
> +				NEXT_ARG();
> +			}
> +			if (NEXT_ARG_OK() &&
> +			    matches(*(argv+1), "bytes") == 0) {
> +				unsigned int max_bytes;
> +				NEXT_ARG();
> +				if (!NEXT_ARG_OK() ||
> +				    get_size(&max_bytes, *(argv+1))) {
> +					explain1("slot bytes");
> +					return -1;
> +				}
> +				slot.max_bytes = (int) max_bytes;
> +				NEXT_ARG();
> +			}
>  		} else if (strcmp(*argv, "help") == 0) {
>  			explain();
>  			return -1;