[RFC PATCH iproute2-next 4/4] tc: q_red: Add support for qevents "mark" and "early"

[Petr Machata]

The "early" qevent matches packets that have been early-dropped. The
"mark" qevent matches packets that have been ECN-marked.

Signed-off-by: Petr Machata <pe...@mellanox.com>
---
 man/man8/tc-red.8 | 18 +++++++++++++++++-
 tc/q_red.c        | 23 ++++++++++++++++++++++-
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/man/man8/tc-red.8 b/man/man8/tc-red.8
index b5aaa986..e74dd330 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 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
+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..7e7dfa05 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"
 
@@ -30,7 +31,8 @@ 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 block IDX] [qevent mark block 
IDX]\n");
 }
 
 #define RED_SUPPORTED_FLAGS (TC_RED_HISTORIC_FLAGS | TC_RED_NODROP)
@@ -38,6 +40,14 @@ static void explain(void)
 static int red_parse_opt(struct qdisc_util *qu, int argc, char **argv,
                         struct nlmsghdr *n, const char *dev)
 {
+       struct qevent_plain qe_early = {};
+       struct qevent_plain qe_mark = {};
+       struct qevent_util qevents[] = {
+               QEVENT("early", plain, &qe_early),
+               QEVENT("mark", plain, &qe_mark),
+               {},
+       };
+
        struct nla_bitfield32 flags_bf = {
                .selector = RED_SUPPORTED_FLAGS,
        };
@@ -109,6 +119,11 @@ 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 +177,12 @@ 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 (qe_early.base.block_idx)
+               addattr32(n, 1024, TCA_RED_EARLY_BLOCK,
+                         qe_early.base.block_idx);
+       if (qe_mark.base.block_idx)
+               addattr32(n, 1024, TCA_RED_MARK_BLOCK,
+                         qe_mark.base.block_idx);
        addattr_nest_end(n, tail);
        return 0;
 }
-- 
2.20.1