From 863f0cafefd9293451fe4682b02c8186a68ad30a Mon Sep 17 00:00:00 2001

From: Phil Sutter <psutter@redhat.com>

Date: Thu, 18 Feb 2016 14:19:36 +0100

Subject: [PATCH] ip: route: add congestion control metric

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1291832

Upstream Status: iproute2.git commit 6ef87f9cce213

commit 6ef87f9cce213cae66098d08e0abc36d67b95244

Author: Daniel Borkmann <dborkman@redhat.com>

Date:   Fri Jan 9 00:13:06 2015 +0100

    ip: route: add congestion control metric

    This patch adds configuration and dumping of congestion control metric

    for ip route, for example:

      ip route add <dst> dev foo congctl [lock] dctcp

    Reference: http://thread.gmane.org/gmane.linux.network/344733

    Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

---

 ip/iproute.c           | 22 ++++++++++++++++++----

 man/man8/ip-route.8.in | 19 ++++++++++++++++++-

 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/ip/iproute.c b/ip/iproute.c

index ea69aa3..d3a5e1c 100644

--- a/ip/iproute.c

+++ b/ip/iproute.c

@@ -53,6 +53,7 @@ static const char *mx_names[RTAX_MAX+1] = {

 	[RTAX_RTO_MIN]	= "rto_min",

 	[RTAX_INITRWND]	= "initrwnd",

 	[RTAX_QUICKACK]	= "quickack",

+	[RTAX_CC_ALGO]	= "congctl",

 };

 static void usage(void) __attribute__((noreturn));

@@ -80,8 +81,7 @@ static void usage(void)

 	fprintf(stderr, "           [ window NUMBER] [ cwnd NUMBER ] [ initcwnd NUMBER ]\n");

 	fprintf(stderr, "           [ ssthresh NUMBER ] [ realms REALM ] [ src ADDRESS ]\n");

 	fprintf(stderr, "           [ rto_min TIME ] [ hoplimit NUMBER ] [ initrwnd NUMBER ]\n");

-	fprintf(stderr, "           [ features FEATURES ]\n");

-	fprintf(stderr, "           [ quickack BOOL ]\n");

+	fprintf(stderr, "           [ features FEATURES ] [ quickack BOOL ] [ congctl NAME ]\n");

 	fprintf(stderr, "TYPE := [ unicast | local | broadcast | multicast | throw |\n");

 	fprintf(stderr, "          unreachable | prohibit | blackhole | nat ]\n");

 	fprintf(stderr, "TABLE_ID := [ local | main | default | all | NUMBER ]\n");

@@ -539,7 +539,7 @@ int print_route(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)

 			mxlock = *(unsigned*)RTA_DATA(mxrta[RTAX_LOCK]);

 		for (i=2; i<= RTAX_MAX; i++) {

-			unsigned val;

+			__u32 val;

 			if (mxrta[i] == NULL)

 				continue;

@@ -548,10 +548,12 @@ int print_route(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)

 				fprintf(fp, " %s", mx_names[i]);

 			else

 				fprintf(fp, " metric %d", i);

+

 			if (mxlock & (1<

 				fprintf(fp, " lock");

+			if (i != RTAX_CC_ALGO)

+				val = rta_getattr_u32(mxrta[i]);

-			val = *(unsigned*)RTA_DATA(mxrta[i]);

 			switch (i) {

 			case RTAX_FEATURES:

 				print_rtax_features(fp, val);

@@ -576,6 +578,10 @@ int print_route(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)

 					fprintf(fp, " %gs", val/1e3);

 				else

 					fprintf(fp, " %ums", val);

+				break;

+			case RTAX_CC_ALGO:

+				fprintf(fp, " %s", rta_getattr_str(mxrta[i]));

+				break;

 			}

 		}

 	}

@@ -928,6 +934,14 @@ static int iproute_modify(int cmd, unsigned flags, int argc, char **argv)

 			if (quickack != 1 && quickack != 0)

 				invarg("\"quickack\" value should be 0 or 1\n", *argv);

 			rta_addattr32(mxrta, sizeof(mxbuf), RTAX_QUICKACK, quickack);

+		} else if (matches(*argv, "congctl") == 0) {

+			NEXT_ARG();

+			if (strcmp(*argv, "lock") == 0) {

+				mxlock |= 1 << RTAX_CC_ALGO;

+				NEXT_ARG();

+			}

+			rta_addattr_l(mxrta, sizeof(mxbuf), RTAX_CC_ALGO, *argv,

+				      strlen(*argv));

 		} else if (matches(*argv, "rttvar") == 0) {

 			unsigned win;

 			NEXT_ARG();

diff --git a/man/man8/ip-route.8.in b/man/man8/ip-route.8.in

index 05fd879..ec4a5b2 100644

--- a/man/man8/ip-route.8.in

+++ b/man/man8/ip-route.8.in

@@ -116,7 +116,9 @@ replace " } "

 .B  features

 .IR FEATURES " ] [ "

 .B  quickack

-.IR BOOL " ]"

+.IR BOOL " ] [ "

+.B  congctl

+.IR NAME " ]"

 .ti -8

 .IR TYPE " := [ "

@@ -433,6 +435,21 @@ sysctl is set to 0.

 Enable or disable quick ack for connections to this destination.

 .TP

+.BI congctl " NAME " "(3.20+ only)"

+.TP

+.BI "congctl lock" " NAME " "(3.20+ only)"

+Sets a specific TCP congestion control algorithm only for a given destination.

+If not specified, Linux keeps the current global default TCP congestion control

+algorithm, or the one set from the application. If the modifier

+.B lock

+is not used, an application may nevertheless overwrite the suggested congestion

+control algorithm for that destination. If the modifier

+.B lock

+is used, then an application is not allowed to overwrite the specified congestion

+control algorithm for that destination, thus it will be enforced/guaranteed to

+use the proposed algorithm.

+

+.TP

 .BI advmss " NUMBER " "(2.3.15+ only)"

 the MSS ('Maximal Segment Size') to advertise to these

 destinations when establishing TCP connections. If it is not given,

-- 

1.8.3.1