iproute2: update cake man page

CAKE supports overriding of its internal classification of
packets through the tc filter mechanism.

Update the man page in our package, even though we don't
build them.  Someone may find the documentation useful.

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
(cherry picked from commit 30598a05385b0ac2380dd4f30037a9f9d0318cf2)

package/network/utils/iproute2/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=iproute2
 PKG_VERSION:=4.18.0
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=@KERNEL/linux/utils/net/iproute2

package/network/utils/iproute2/patches/190-add-cake-to-tc.patch

@@ -121,7 +121,7 @@
  #endif
 --- /dev/null
 +++ b/man/man8/tc-cake.8
-@@ -0,0 +1,632 @@
+@@ -0,0 +1,710 @@
 +.TH CAKE 8 "19 July 2018" "iproute2" "Linux"
 +.SH NAME
 +CAKE \- Common Applications Kept Enhanced (CAKE)
@@ -197,6 +197,12 @@
 +]
 +.br
 +[
++.BR split-gso*
++|
++.BR no-split-gso
++]
++.br
++[
 +.BR ack-filter
 +|
 +.BR ack-filter-aggressive
@@ -670,6 +676,78 @@
 +case for Comcast Cable, among others), it is best to use a single queue
 +"besteffort" mode with wash.
 +
++.PP
++.B split-gso
++
++.br
++	This option controls whether CAKE will split General Segmentation
++Offload (GSO) super-packets into their on-the-wire components and
++dequeue them individually.
++
++.br
++Super-packets are created by the networking stack to improve efficiency.
++However, because they are larger they take longer to dequeue, which
++translates to higher latency for competing flows, especially at lower
++bandwidths. CAKE defaults to splitting GSO packets to achieve the lowest
++possible latency. At link speeds higher than 10 Gbps, setting the
++no-split-gso parameter can increase the maximum achievable throughput by
++retaining the full GSO packets.
++
++.SH OVERRIDING CLASSIFICATION WITH TC FILTERS
++
++CAKE supports overriding of its internal classification of packets through the
++tc filter mechanism. Packets can be assigned to different priority tins by
++setting the
++.B priority
++field on the skb, and the flow hashing can be overridden by setting the
++.B classid
++parameter.
++
++.PP
++.B Tin override
++
++.br
++        To assign a priority tin, the major number of the priority field needs
++to match the qdisc handle of the cake instance; if it does, the minor number
++will be interpreted as the tin index. For example, to classify all ICMP packets
++as 'bulk', the following filter can be used:
++
++.br
++        # tc qdisc replace dev eth0 handle 1: root cake diffserv3
++        # tc filter add dev eth0 parent 1: protocol ip prio 1 \\
++          u32 match icmp type 0 0 action skbedit priority 1:1
++
++.PP
++.B Flow hash override
++
++.br
++        To override flow hashing, the classid can be set. CAKE will interpret
++the major number of the classid as the host hash used in host isolation mode,
++and the minor number as the flow hash used for flow-based queueing. One or both
++of those can be set, and will be used if the relevant flow isolation parameter
++is set (i.e., the major number will be ignored if CAKE is not configured in
++hosts mode, and the minor number will be ignored if CAKE is not configured in
++flows mode).
++
++.br
++This example will assign all ICMP packets to the first queue:
++
++.br
++        # tc qdisc replace dev eth0 handle 1: root cake
++        # tc filter add dev eth0 parent 1: protocol ip prio 1 \\
++          u32 match icmp type 0 0 classid 0:1
++
++.br
++If only one of the host and flow overrides is set, CAKE will compute the other
++hash from the packet as normal. Note, however, that the host isolation mode
++works by assigning a host ID to the flow queue; so if overriding both host and
++flow, the same flow cannot have more than one host assigned. In addition, it is
++not possible to assign different source and destination host IDs through the
++override mechanism; if a host ID is assigned, it will be used as both source and
++destination host.
++
++
++
 +.SH EXAMPLES
 +# tc qdisc delete root dev eth0
 +.br
@@ -879,6 +957,7 @@
 +	__u64 bandwidth = 0;
 +	int ack_filter = -1;
 +	struct rtattr *tail;
++	int split_gso = -1;
 +	int unlimited = 0;
 +	int flowmode = -1;
 +	int autorate = -1;
@@ -888,7 +967,6 @@
 +	int nat = -1;
 +	int atm = -1;
 +	int mpu = 0;
-+	int split_gso = -1;
 +
 +	while (argc > 0) {
 +		if (strcmp(*argv, "bandwidth") == 0) {