lwn.git/include/uapi/linux/pkt_sched.h, branch docs-5.3

taprio: Add support for cycle-time-extension

2019-05-01T15:58:51+00:00

IEEE 802.1Q-2018 defines the concept of a cycle-time-extension, so the last entry of a schedule before the start of a new schedule can be extended, so "too-short" entries can be avoided. Signed-off-by: Vinicius Costa Gomes Signed-off-by: David S. Miller

taprio: Add support for setting the cycle-time manually

2019-05-01T15:58:51+00:00

IEEE 802.1Q-2018 defines that a the cycle-time of a schedule may be overridden, so the schedule is truncated to a determined "width". Signed-off-by: Vinicius Costa Gomes Signed-off-by: David S. Miller

taprio: Add support adding an admin schedule

2019-05-01T15:58:51+00:00

The IEEE 802.1Q-2018 defines two "types" of schedules, the "Oper" (from operational?) and "Admin" ones. Up until now, 'taprio' only had support for the "Oper" one, added when the qdisc is created. This adds support for the "Admin" one, which allows the .change() operation to be supported. Just for clarification, some quick (and dirty) definitions, the "Oper" schedule is the currently (as in this instant) running one, and it's read-only. The "Admin" one is the one that the system configurator has installed, it can be changed, and it will be "promoted" to "Oper" when it's 'base-time' is reached. The idea behing this patch is that calling something like the below, (after taprio is already configured with an initial schedule): $ tc qdisc change taprio dev IFACE parent root \ base-time X \ sched-entry \ ... Will cause a new admin schedule to be created and programmed to be "promoted" to "Oper" at instant X. If an "Admin" schedule already exists, it will be overwritten with the new parameters. Up until now, there was some code that was added to ease the support of changing a single entry of a schedule, but was ultimately unused. Now, that we have support for "change" with more well thought semantics, updating a single entry seems to be less useful. So we remove what is in practice dead code, and return a "not supported" error if the user tries to use it. If changing a single entry would make the user's life easier we may ressurrect this idea, but at this point, removing it simplifies the code. For now, only the schedule specific bits are allowed to be added for a new schedule, that means that 'clockid', 'num_tc', 'map' and 'queues' cannot be modified. Example: $ tc qdisc change dev IFACE parent root handle 100 taprio \ base-time $BASE_TIME \ sched-entry S 00 500000 \ sched-entry S 0f 500000 \ clockid CLOCK_TAI The only change in the netlink API introduced by this change is the introduction of an "admin" type in the response to a dump request, that type allows userspace to separate the "oper" schedule from the "admin" schedule. If userspace doesn't support the "admin" type, it will only display the "oper" schedule. Signed-off-by: Vinicius Costa Gomes Signed-off-by: David S. Miller

sch_cake: Permit use of connmarks as tin classifiers

2019-03-04T04:14:28+00:00

Add flag 'FWMARK' to enable use of firewall connmarks as tin selector. The connmark (skbuff->mark) needs to be in the range 1->tin_cnt ie. for diffserv3 the mark needs to be 1->3. Background Typically CAKE uses DSCP as the basis for tin selection. DSCP values are relatively easily changed as part of the egress path, usually with iptables & the mangle table, ingress is more challenging. CAKE is often used on the WAN interface of a residential gateway where passthrough of DSCP from the ISP is either missing or set to unhelpful values thus use of ingress DSCP values for tin selection isn't helpful in that environment. An approach to solving the ingress tin selection problem is to use CAKE's understanding of tc filters. Naive tc filters could match on source/destination port numbers and force tin selection that way, but multiple filters don't scale particularly well as each filter must be traversed whether it matches or not. e.g. a simple example to map 3 firewall marks to tins: MAJOR=$( tc qdisc show dev $DEV | head -1 | awk '{print $3}' ) tc filter add dev $DEV parent $MAJOR protocol all handle 0x01 fw action skbedit priority ${MAJOR}1 tc filter add dev $DEV parent $MAJOR protocol all handle 0x02 fw action skbedit priority ${MAJOR}2 tc filter add dev $DEV parent $MAJOR protocol all handle 0x03 fw action skbedit priority ${MAJOR}3 Another option is to use eBPF cls_act with tc filters e.g. MAJOR=$( tc qdisc show dev $DEV | head -1 | awk '{print $3}' ) tc filter add dev $DEV parent $MAJOR bpf da obj my-bpf-fwmark-to-class.o This has the disadvantages of a) needing someone to write & maintain the bpf program, b) a bpf toolchain to compile it and c) needing to hardcode the major number in the bpf program so it matches the cake instance (or forcing the cake instance to a particular major number) since the major number cannot be passed to the bpf program via tc command line. As already hinted at by the previous examples, it would be helpful to associate tins with something that survives the Internet path and ideally allows tin selection on both egress and ingress. Netfilter's conntrack permits setting an identifying mark on a connection which can also be restored to an ingress packet with tc action connmark e.g. tc filter add dev eth0 parent ffff: protocol all prio 10 u32 \ match u32 0 0 flowid 1:1 action connmark action mirred egress redirect dev ifb1 Since tc's connmark action has restored any connmark into skb->mark, any of the previous solutions are based upon it and in one form or another copy that mark to the skb->priority field where again CAKE picks this up. This change cuts out at least one of the (less intuitive & non-scalable) middlemen and permit direct access to skb->mark. Signed-off-by: Kevin Darbyshire-Bryant Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: David S. Miller

net: sched: pie: add more cases to auto-tune alpha and beta

2019-02-25T22:21:03+00:00

The current implementation scales the local alpha and beta variables in the calculate_probability function by the same amount for all values of drop probability below 1%. RFC 8033 suggests using additional cases for auto-tuning alpha and beta when the drop probability is less than 1%. In order to add more auto-tuning cases, MAX_PROB must be scaled by u64 instead of u32 to prevent underflow when scaling the local alpha and beta variables in the calculate_probability function. Signed-off-by: Mohit P. Tahiliani Signed-off-by: Dhaval Khandla Signed-off-by: Hrishikesh Hiraskar Signed-off-by: Manish Kumar B Signed-off-by: Sachin D. Patil Signed-off-by: Leslie Monis Acked-by: Dave Taht Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net: sched: gred: allow manipulating per-DP RED flags

2018-11-17T07:08:51+00:00

Allow users to set and dump RED flags (ECN enabled and harddrop) on per-virtual queue basis. Validation of attributes is split from changes to make sure we won't have to undo previous operations when we find out configuration is invalid. The objective is to allow changing per-Qdisc parameters without overwriting the per-vq configured flags. Old user space will not pass the TCA_GRED_VQ_FLAGS attribute and per-Qdisc flags will always get propagated to the virtual queues. New user space which wants to make use of per-vq flags should set per-Qdisc flags to 0 and then configure per-vq flags as it sees fit. Once per-vq flags are set per-Qdisc flags can't be changed to non-zero. Vice versa - if the per-Qdisc flags are non-zero the TCA_GRED_VQ_FLAGS attribute has to either be omitted or set to the same value as per-Qdisc flags. Update per-Qdisc parameters: per-Qdisc | per-VQ | result 0 | 0 | all vq flags updated 0 | non-0 | error (vq flags in use) non-0 | 0 | -- impossible -- non-0 | non-0 | all vq flags updated Update per-VQ state (flags parameter not specified): no change to flags Update per-VQ state (flags parameter set): per-Qdisc | per-VQ | result 0 | any | per-vq flags updated non-0 | 0 | -- impossible -- non-0 | non-0 | error (per-Qdisc flags in use) Signed-off-by: Jakub Kicinski Reviewed-by: John Hurley Signed-off-by: David S. Miller

net: sched: gred: provide a better structured dump and expose stats

2018-11-17T07:08:51+00:00

Currently all GRED's virtual queue data is dumped in a single array in a single attribute. This makes it pretty much impossible to add new fields. In order to expose more detailed stats add a new set of attributes. We can now expose the 64 bit value of bytesin and all the mark stats which were not part of the original design. Signed-off-by: Jakub Kicinski Reviewed-by: John Hurley Signed-off-by: David S. Miller

net_sched: sch_fq: add dctcp-like marking

2018-11-11T21:59:21+00:00

Similar to 80ba92fa1a92 ("codel: add ce_threshold attribute") After EDT adoption, it became easier to implement DCTCP-like CE marking. In many cases, queues are not building in the network fabric but on the hosts themselves. If packets leaving fq missed their Earliest Departure Time by XXX usec, we mark them with ECN CE. This gives a feedback (after one RTT) to the sender to slow down and find better operating mode. Example : tc qd replace dev eth0 root fq ce_threshold 2.5ms Signed-off-by: Eric Dumazet Acked-by: Neal Cardwell Signed-off-by: David S. Miller

tc: Add support for configuring the taprio scheduler

2018-10-04T20:52:23+00:00

This traffic scheduler allows traffic classes states (transmission allowed/not allowed, in the simplest case) to be scheduled, according to a pre-generated time sequence. This is the basis of the IEEE 802.1Qbv specification. Example configuration: tc qdisc replace dev enp3s0 parent root handle 100 taprio \ num_tc 3 \ map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 \ queues 1@0 1@1 2@2 \ base-time 1528743495910289987 \ sched-entry S 01 300000 \ sched-entry S 02 300000 \ sched-entry S 04 300000 \ clockid CLOCK_TAI The configuration format is similar to mqprio. The main difference is the presence of a schedule, built by multiple "sched-entry" definitions, each entry has the following format: sched-entry The only supported is "S", which means "SetGateStates", following the IEEE 802.1Qbv-2015 definition (Table 8-6). is a bitmask where each bit is a associated with a traffic class, so bit 0 (the least significant bit) being "on" means that traffic class 0 is "active" for that schedule entry. is a time duration in nanoseconds that specifies for how long that state defined by and should be held before moving to the next entry. This schedule is circular, that is, after the last entry is executed it starts from the first one, indefinitely. The other parameters can be defined as follows: - base-time: specifies the instant when the schedule starts, if 'base-time' is a time in the past, the schedule will start at base-time + (N * cycle-time) where N is the smallest integer so the resulting time is greater than "now", and "cycle-time" is the sum of all the intervals of the entries in the schedule; - clockid: specifies the reference clock to be used; The parameters should be similar to what the IEEE 802.1Q family of specification defines. Signed-off-by: Vinicius Costa Gomes Signed-off-by: David S. Miller

net/sched: fix type of htb statistics

2018-09-02T20:57:12+00:00

tokens and ctokens are defined as s64 in htb_class structure, and clamped to 32bits value during netlink dumps: cl->xstats.tokens = clamp_t(s64, PSCHED_NS2TICKS(cl->tokens), INT_MIN, INT_MAX); Defining it as u32 is working since userspace (tc) is printing it as signed int, but a correct definition from the beginning is probably better. In the same time, 'giants' structure member is unused since years, so update the comment to mark it unused. Signed-off-by: Florent Fourcot Signed-off-by: David S. Miller