Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'net-ipv4-allow-directed-broadcast-routes-to-use-dst-hint'
Oscar Maes says:
====================
net: ipv4: allow directed broadcast routes to use dst hint
Currently, ip_extract_route_hint uses RTN_BROADCAST to decide
whether to use the route dst hint mechanism.
This check is too strict, as it prevents directed broadcast
routes from using the hint, resulting in poor performance
during bursts of directed broadcast traffic.
This series fixes this, and adds a new selftest to ensure
this does not regress.
Link to v2: https://lore.kernel.org/20250814140309.3742-1-oscmaes92@gmail.com
====================
Link: https://patch.msgid.link/20250819174642.5148-1-oscmaes92@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+88
-5
+7
-4
net/ipv4/ip_input.c
+7
-4
net/ipv4/ip_input.c
···
587
587
}
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588
589
589
static struct sk_buff *ip_extract_route_hint(const struct net *net,
590
-
struct sk_buff *skb, int rt_type)
590
+
struct sk_buff *skb)
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591
{
592
-
if (fib4_has_custom_rules(net) || rt_type == RTN_BROADCAST ||
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+
const struct iphdr *iph = ip_hdr(skb);
593
+
594
+
if (fib4_has_custom_rules(net) ||
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+
ipv4_is_lbcast(iph->daddr) ||
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+
ipv4_is_zeronet(iph->daddr) ||
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IPCB(skb)->flags & IPSKB_MULTIPATH)
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return NULL;
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599
···
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618
623
619
dst = skb_dst(skb);
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if (curr_dst != dst) {
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-
hint = ip_extract_route_hint(net, skb,
626
-
dst_rtable(dst)->rt_type);
621
+
hint = ip_extract_route_hint(net, skb);
627
622
628
623
/* dispatch old sublist */
629
624
if (!list_empty(&sublist))
+1
-1
net/ipv4/route.c
+1
-1
net/ipv4/route.c
+1
tools/testing/selftests/net/Makefile
+1
tools/testing/selftests/net/Makefile
+79
tools/testing/selftests/net/route_hint.sh
+79
tools/testing/selftests/net/route_hint.sh
···
1
+
#!/bin/bash
2
+
# SPDX-License-Identifier: GPL-2.0
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+
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+
# This test ensures directed broadcast routes use dst hint mechanism
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+
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+
source lib.sh
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+
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+
CLIENT_IP4="192.168.0.1"
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+
SERVER_IP4="192.168.0.2"
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+
BROADCAST_ADDRESS="192.168.0.255"
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+
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+
setup() {
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+
setup_ns CLIENT_NS SERVER_NS
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+
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+
ip -net "${SERVER_NS}" link add link1 type veth peer name link0 netns "${CLIENT_NS}"
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+
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+
ip -net "${CLIENT_NS}" link set link0 up
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+
ip -net "${CLIENT_NS}" addr add "${CLIENT_IP4}/24" dev link0
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+
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+
ip -net "${SERVER_NS}" link set link1 up
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+
ip -net "${SERVER_NS}" addr add "${SERVER_IP4}/24" dev link1
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+
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+
ip netns exec "${CLIENT_NS}" ethtool -K link0 tcp-segmentation-offload off
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+
ip netns exec "${SERVER_NS}" sh -c "echo 500000000 > /sys/class/net/link1/gro_flush_timeout"
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+
ip netns exec "${SERVER_NS}" sh -c "echo 1 > /sys/class/net/link1/napi_defer_hard_irqs"
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+
ip netns exec "${SERVER_NS}" ethtool -K link1 generic-receive-offload on
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+
}
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+
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+
cleanup() {
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+
ip -net "${SERVER_NS}" link del link1
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+
cleanup_ns "${CLIENT_NS}" "${SERVER_NS}"
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+
}
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+
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+
directed_bcast_hint_test()
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+
{
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+
local rc=0
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+
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+
echo "Testing for directed broadcast route hint"
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+
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+
orig_in_brd=$(ip netns exec "${SERVER_NS}" lnstat -j -i1 -c1 | jq '.in_brd')
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+
ip netns exec "${CLIENT_NS}" mausezahn link0 -a own -b bcast -A "${CLIENT_IP4}" \
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+
-B "${BROADCAST_ADDRESS}" -c1 -t tcp "sp=1-100,dp=1234,s=1,a=0" -p 5 -q
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+
sleep 1
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+
new_in_brd=$(ip netns exec "${SERVER_NS}" lnstat -j -i1 -c1 | jq '.in_brd')
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+
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+
res=$(echo "${new_in_brd} - ${orig_in_brd}" | bc)
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+
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+
if [ "${res}" -lt 100 ]; then
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+
echo "[ OK ]"
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+
rc="${ksft_pass}"
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else
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echo "[FAIL] expected in_brd to be under 100, got ${res}"
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+
rc="${ksft_fail}"
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+
fi
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+
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+
return "${rc}"
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+
}
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+
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+
if [ ! -x "$(command -v mausezahn)" ]; then
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+
echo "SKIP: Could not run test without mausezahn tool"
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+
exit "${ksft_skip}"
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+
fi
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+
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+
if [ ! -x "$(command -v jq)" ]; then
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+
echo "SKIP: Could not run test without jq tool"
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+
exit "${ksft_skip}"
67
+
fi
68
+
69
+
if [ ! -x "$(command -v bc)" ]; then
70
+
echo "SKIP: Could not run test without bc tool"
71
+
exit "${ksft_skip}"
72
+
fi
73
+
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+
trap cleanup EXIT
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+
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+
setup
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+
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+
directed_bcast_hint_test
79
+
exit $?