From 01bb0bcd002ca80487d3844082c5488a13599bb9 Mon Sep 17 00:00:00 2001 From: Petr Machata Date: Tue, 30 Jun 2020 13:14:50 +0300 Subject: [PATCH 1/3] tc: Add helpers to support qevent handling Introduce a set of helpers to make it easy to add support for qevents into qdisc. The idea behind this is that qevent types will be generally reused between qdiscs, rather than each having a completely idiosyncratic set of qevents. The qevent module holds functions for parsing, dumping and formatting of these common qevent types, and for dispatch to the appropriate set of handlers based on the qevent name. Signed-off-by: Petr Machata Signed-off-by: David Ahern --- tc/Makefile | 1 + tc/tc_qevent.c | 202 +++++++++++++++++++++++++++++++++++++++++++++++++ tc/tc_qevent.h | 49 ++++++++++++ 3 files changed, 252 insertions(+) create mode 100644 tc/tc_qevent.c create mode 100644 tc/tc_qevent.h diff --git a/tc/Makefile b/tc/Makefile index 79c9c1dd..5a517af2 100644 --- a/tc/Makefile +++ b/tc/Makefile @@ -122,6 +122,7 @@ TCLIB += tc_red.o TCLIB += tc_cbq.o TCLIB += tc_estimator.o TCLIB += tc_stab.o +TCLIB += tc_qevent.o CFLAGS += -DCONFIG_GACT -DCONFIG_GACT_PROB ifneq ($(IPT_LIB_DIR),) diff --git a/tc/tc_qevent.c b/tc/tc_qevent.c new file mode 100644 index 00000000..1f8e6506 --- /dev/null +++ b/tc/tc_qevent.c @@ -0,0 +1,202 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause + +/* + * Helpers for handling qevents. + */ + +#include +#include + +#include "tc_qevent.h" +#include "utils.h" + +void qevents_init(struct qevent_util *qevents) +{ + if (!qevents) + return; + + for (; qevents->id; qevents++) + memset(qevents->data, 0, qevents->data_size); +} + +int qevent_parse(struct qevent_util *qevents, int *p_argc, char ***p_argv) +{ + char **argv = *p_argv; + int argc = *p_argc; + const char *name = *argv; + int err; + + if (!qevents) + goto out; + + for (; qevents->id; qevents++) { + if (strcmp(name, qevents->id) == 0) { + NEXT_ARG(); + err = qevents->parse_qevent(qevents, &argc, &argv); + if (err) + return err; + + *p_argc = argc; + *p_argv = argv; + return 0; + } + } + +out: + fprintf(stderr, "Unknown qevent `%s'\n", name); + return -1; +} + +int qevents_read(struct qevent_util *qevents, struct rtattr **tb) +{ + int err; + + if (!qevents) + return 0; + + for (; qevents->id; qevents++) { + if (tb[qevents->attr]) { + err = qevents->read_qevent(qevents, tb); + if (err) + return err; + } + } + + return 0; +} + +void qevents_print(struct qevent_util *qevents, FILE *f) +{ + int first = true; + + if (!qevents) + return; + + for (; qevents->id; qevents++) { + struct qevent_base *qeb = qevents->data; + + if (qeb->block_idx) { + if (first) { + open_json_array(PRINT_JSON, "qevents"); + first = false; + } + + open_json_object(NULL); + print_string(PRINT_ANY, "kind", " qevent %s", qevents->id); + qevents->print_qevent(qevents, f); + close_json_object(); + } + } + + if (!first) + close_json_array(PRINT_ANY, ""); +} + +int qevents_dump(struct qevent_util *qevents, struct nlmsghdr *n) +{ + int err; + + if (!qevents) + return 0; + + for (; qevents->id; qevents++) { + struct qevent_base *qeb = qevents->data; + + if (qeb->block_idx) { + err = qevents->dump_qevent(qevents, n); + if (err) + return err; + } + } + + return 0; +} + +static int parse_block_idx(const char *arg, struct qevent_base *qeb) +{ + if (qeb->block_idx) { + fprintf(stderr, "Qevent block index already specified\n"); + return -1; + } + + if (get_unsigned(&qeb->block_idx, arg, 10) || !qeb->block_idx) { + fprintf(stderr, "Illegal qevent block index\n"); + return -1; + } + + return 0; +} + +static int read_block_idx(struct rtattr *attr, struct qevent_base *qeb) +{ + if (qeb->block_idx) { + fprintf(stderr, "Qevent block index already specified\n"); + return -1; + } + + qeb->block_idx = rta_getattr_u32(attr); + if (!qeb->block_idx) { + fprintf(stderr, "Illegal qevent block index\n"); + return -1; + } + + return 0; +} + +static void print_block_idx(FILE *f, __u32 block_idx) +{ + print_uint(PRINT_ANY, "block", " block %u", block_idx); +} + +int qevent_parse_plain(struct qevent_util *qu, int *p_argc, char ***p_argv) +{ + struct qevent_plain *qe = qu->data; + char **argv = *p_argv; + int argc = *p_argc; + + if (qe->base.block_idx) { + fprintf(stderr, "Duplicate qevent\n"); + return -1; + } + + while (argc > 0) { + if (strcmp(*argv, "block") == 0) { + NEXT_ARG(); + if (parse_block_idx(*argv, &qe->base)) + return -1; + } else { + break; + } + NEXT_ARG_FWD(); + } + + if (!qe->base.block_idx) { + fprintf(stderr, "Unspecified qevent block index\n"); + return -1; + } + + *p_argc = argc; + *p_argv = argv; + return 0; +} + +int qevent_read_plain(struct qevent_util *qu, struct rtattr **tb) +{ + struct qevent_plain *qe = qu->data; + + return read_block_idx(tb[qu->attr], &qe->base); +} + +void qevent_print_plain(struct qevent_util *qu, FILE *f) +{ + struct qevent_plain *qe = qu->data; + + print_block_idx(f, qe->base.block_idx); +} + +int qevent_dump_plain(struct qevent_util *qu, struct nlmsghdr *n) +{ + struct qevent_plain *qe = qu->data; + + return addattr32(n, 1024, qu->attr, qe->base.block_idx); +} diff --git a/tc/tc_qevent.h b/tc/tc_qevent.h new file mode 100644 index 00000000..574e7cff --- /dev/null +++ b/tc/tc_qevent.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _TC_QEVENT_H_ +#define _TC_QEVENT_H_ + +#include +#include + +struct qevent_base { + __u32 block_idx; +}; + +struct qevent_util { + const char *id; + int (*parse_qevent)(struct qevent_util *qu, int *argc, char ***argv); + int (*read_qevent)(struct qevent_util *qu, struct rtattr **tb); + void (*print_qevent)(struct qevent_util *qu, FILE *f); + int (*dump_qevent)(struct qevent_util *qu, struct nlmsghdr *n); + size_t data_size; + void *data; + int attr; +}; + +#define QEVENT(_name, _form, _data, _attr) \ + { \ + .id = _name, \ + .parse_qevent = qevent_parse_##_form, \ + .read_qevent = qevent_read_##_form, \ + .print_qevent = qevent_print_##_form, \ + .dump_qevent = qevent_dump_##_form, \ + .data_size = sizeof(struct qevent_##_form), \ + .data = _data, \ + .attr = _attr, \ + } + +void qevents_init(struct qevent_util *qevents); +int qevent_parse(struct qevent_util *qevents, int *p_argc, char ***p_argv); +int qevents_read(struct qevent_util *qevents, struct rtattr **tb); +int qevents_dump(struct qevent_util *qevents, struct nlmsghdr *n); +void qevents_print(struct qevent_util *qevents, FILE *f); + +struct qevent_plain { + struct qevent_base base; +}; +int qevent_parse_plain(struct qevent_util *qu, int *p_argc, char ***p_argv); +int qevent_read_plain(struct qevent_util *qu, struct rtattr **tb); +void qevent_print_plain(struct qevent_util *qu, FILE *f); +int qevent_dump_plain(struct qevent_util *qu, struct nlmsghdr *n); + +#endif From 3cf51fb3c86f330c71e762b8b48cfdc3ffbb3e3c Mon Sep 17 00:00:00 2001 From: Petr Machata Date: Tue, 30 Jun 2020 13:14:51 +0300 Subject: [PATCH 2/3] man: tc: Describe qevents Add some general remarks about qevents. Signed-off-by: Petr Machata Signed-off-by: David Ahern --- man/man8/tc.8 | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/man/man8/tc.8 b/man/man8/tc.8 index e8e0cd0f..eba73dbf 100644 --- a/man/man8/tc.8 +++ b/man/man8/tc.8 @@ -254,6 +254,25 @@ Traffic control filter that matches every packet. See .BR tc-matchall (8) for details. +.SH QEVENTS +Qdiscs may invoke user-configured actions when certain interesting events +take place in the qdisc. Each qevent can either be unused, or can have a +block attached to it. To this block are then attached filters using the "tc +block BLOCK_IDX" syntax. The block is executed when the qevent associated +with the attachment point takes place. For example, packet could be +dropped, or delayed, etc., depending on the qdisc and the qevent in +question. + +For example: +.PP +.RS +tc qdisc add dev eth0 root handle 1: red limit 500K avpkt 1K \\ + qevent early_drop block 10 +.RE +.RS +tc filter add block 10 matchall action mirred egress mirror dev eth1 +.RE + .SH CLASSLESS QDISCS The classless qdiscs are: .TP From d0e45043857191034098ff08b8531a43b8c57cfe Mon Sep 17 00:00:00 2001 From: Petr Machata Date: Tue, 30 Jun 2020 13:14:52 +0300 Subject: [PATCH 3/3] tc: q_red: Add support for qevents "mark" and "early_drop" The "early_drop" qevent matches packets that have been early-dropped. The "mark" qevent matches packets that have been ECN-marked. Signed-off-by: Petr Machata Signed-off-by: David Ahern --- man/man8/tc-red.8 | 18 +++++++++++++++++- tc/q_red.c | 30 +++++++++++++++++++++++++++--- 2 files changed, 44 insertions(+), 4 deletions(-) diff --git a/man/man8/tc-red.8 b/man/man8/tc-red.8 index b5aaa986..662e4d8b 100644 --- a/man/man8/tc-red.8 +++ b/man/man8/tc-red.8 @@ -17,7 +17,11 @@ packets rate .B ] [ probability chance -.B ] [ adaptive ] +.B ] [ adaptive ] [ qevent early_drop block +index +.B ] [ qevent mark block +index +.B ] .SH DESCRIPTION Random Early Detection is a classless qdisc which manages its queue size @@ -134,6 +138,18 @@ Goal of Adaptive RED is to make 'probability' dynamic value between 1% and 50% t .B (max - min) / 2 .fi +.SH QEVENTS +See tc (8) for some general notes about qevents. The RED qdisc supports the +following qevents: + +.TP +early_drop +The associated block is executed when packets are early-dropped. This includes +non-ECT packets in ECN mode. +.TP +mark +The associated block is executed when packets are marked in ECN mode. + .SH EXAMPLE .P diff --git a/tc/q_red.c b/tc/q_red.c index 53181c82..97856f03 100644 --- a/tc/q_red.c +++ b/tc/q_red.c @@ -22,6 +22,7 @@ #include "utils.h" #include "tc_util.h" +#include "tc_qevent.h" #include "tc_red.h" @@ -30,11 +31,20 @@ static void explain(void) fprintf(stderr, "Usage: ... red limit BYTES [min BYTES] [max BYTES] avpkt BYTES [burst PACKETS]\n" " [adaptive] [probability PROBABILITY] [bandwidth KBPS]\n" - " [ecn] [harddrop] [nodrop]\n"); + " [ecn] [harddrop] [nodrop]\n" + " [qevent early_drop block IDX] [qevent mark block IDX]\n"); } #define RED_SUPPORTED_FLAGS (TC_RED_HISTORIC_FLAGS | TC_RED_NODROP) +static struct qevent_plain qe_early_drop = {}; +static struct qevent_plain qe_mark = {}; +static struct qevent_util qevents[] = { + QEVENT("early_drop", plain, &qe_early_drop, TCA_RED_EARLY_DROP_BLOCK), + QEVENT("mark", plain, &qe_mark, TCA_RED_MARK_BLOCK), + {}, +}; + static int red_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n, const char *dev) { @@ -51,6 +61,8 @@ static int red_parse_opt(struct qdisc_util *qu, int argc, char **argv, __u32 max_P; struct rtattr *tail; + qevents_init(qevents); + while (argc > 0) { if (strcmp(*argv, "limit") == 0) { NEXT_ARG(); @@ -109,6 +121,11 @@ static int red_parse_opt(struct qdisc_util *qu, int argc, char **argv, flags_bf.value |= TC_RED_ADAPTATIVE; } else if (strcmp(*argv, "adaptive") == 0) { flags_bf.value |= TC_RED_ADAPTATIVE; + } else if (matches(*argv, "qevent") == 0) { + NEXT_ARG(); + if (qevent_parse(qevents, &argc, &argv)) + return -1; + continue; } else if (strcmp(*argv, "help") == 0) { explain(); return -1; @@ -162,6 +179,8 @@ static int red_parse_opt(struct qdisc_util *qu, int argc, char **argv, max_P = probability * pow(2, 32); addattr_l(n, 1024, TCA_RED_MAX_P, &max_P, sizeof(max_P)); addattr_l(n, 1024, TCA_RED_FLAGS, &flags_bf, sizeof(flags_bf)); + if (qevents_dump(qevents, n)) + return -1; addattr_nest_end(n, tail); return 0; } @@ -203,12 +222,12 @@ static int red_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt) print_uint(PRINT_JSON, "min", NULL, qopt->qth_min); print_string(PRINT_FP, NULL, "min %s ", sprint_size(qopt->qth_min, b2)); print_uint(PRINT_JSON, "max", NULL, qopt->qth_max); - print_string(PRINT_FP, NULL, "max %s ", sprint_size(qopt->qth_max, b3)); + print_string(PRINT_FP, NULL, "max %s", sprint_size(qopt->qth_max, b3)); tc_red_print_flags(qopt->flags); if (show_details) { - print_uint(PRINT_ANY, "ewma", "ewma %u ", qopt->Wlog); + print_uint(PRINT_ANY, "ewma", " ewma %u ", qopt->Wlog); if (max_P) print_float(PRINT_ANY, "probability", "probability %lg ", max_P / pow(2, 32)); @@ -217,6 +236,11 @@ static int red_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt) print_uint(PRINT_ANY, "Scell_log", "Scell_log %u", qopt->Scell_log); } + + qevents_init(qevents); + if (qevents_read(qevents, tb)) + return -1; + qevents_print(qevents, f); return 0; }