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libvirt/tests/networkxml2firewalldata/forward-dev-linux.nftables

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network: add tc filter rule to nftables backend to fix checksum of DHCP responses Please see the commit log for commit v10.9.0-rc1-1-g42ab0148dd for the history and explanation of the problem that this patch is fixing. A shorter explanation is that when a guest is connected to a libvirt virtual network using a virtio-net adapter with in-kernel "vhost-net" packet processing enabled, it will fail to acquire an IP address from a DHCP seever running on the host. In commit v10.9.0-rc1-1-g42ab0148dd we tried fixing this by *zeroing out* the checksums of these packets with an nftables rule (nftables can't recompute the checksum, but it can set it to 0) . This *appeared* to work initially, but it turned out that zeroing the checksum ends up breaking dhcp packets on *non* virtio/vhost-net guest interfaces. That attempt was reverted in commit v10.9.0-rc2. Fortunately, there is an existing way to recompute the checksum of a packet as it leaves an interface - the "tc" (traffic control) utility that libvirt already uses for bandwidth management. This patch uses a tc filter rule to match dhcp response packets on the bridge and recompute their checksum. The filter rule must be attached to a tc qdisc, which may also have a filter attached for bandwidth management (in the <bandwidth> element of the network config). Not only must we add the qdisc only once (which was already handled by the patch two prior to this one), but also the filter rule for checksum fixing and the filter rule for bandwidth management must be different priorities so they don't clash; this is solved by adding the checksum-fix filter with "priority 2", while the bandwidth management filter remains "priority 1" (both will always be evaluated anyway, it's just a matter of which is evaluated first). So far this method has worked with every different guest we could throw at it, including several that failed with the previous method. Fixes: b89c4991daa0ee9371f10937fab3b03c5ffdabc6 Reported-by: Rich Jones <rjones@redhat.com> Reported-by: Andrea Bolognani <abologna@redhat.com> Fix-Suggested-by: Eric Garver <egarver@redhat.com> Fix-Suggested-by: Phil Sutter <psutter@redhat.com> Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2024-11-26 03:24:49 +00:00
tc \
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show \
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virbr0 \
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1:
tc \
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root \
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filter \
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udp
network: add more firewall test cases This patch adds some previously missing test cases that test for proper firewall rule creation when the following are included in the network definition: * <forward dev='blah'> * no forward element (an "isolated" network) * nat port range when only ipv4 is nat-ed * nat port range when both ipv4 & ipv6 are nated Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Laine Stump <laine@redhat.com>
2024-06-21 12:17:58 +00:00
nft \
-ae insert \
rule \
ip \
libvirt_network \
guest_output \
iif \
virbr0 \
counter \
reject
nft \
-ae insert \
rule \
ip \
libvirt_network \
guest_input \
oif \
virbr0 \
counter \
reject
nft \
-ae insert \
rule \
ip \
libvirt_network \
guest_cross \
iif \
virbr0 \
oif \
virbr0 \
counter \
accept
nft \
-ae insert \
rule \
ip \
libvirt_network \
guest_output \
ip \
saddr \
192.168.122.0/24 \
iif \
virbr0 \
oifname \
enp0s7 \
counter \
accept
nft \
-ae insert \
rule \
ip \
libvirt_network \
guest_input \
iifname \
enp0s7 \
oif \
virbr0 \
ip \
daddr \
192.168.122.0/24 \
ct \
state \
related,established \
counter \
accept
nft \
-ae insert \
rule \
ip \
libvirt_network \
guest_nat \
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saddr \
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ip \
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'!=' \
192.168.122.0/24 \
oifname \
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counter \
masquerade
nft \
-ae insert \
rule \
ip \
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guest_nat \
meta \
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udp \
ip \
saddr \
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ip \
daddr \
'!=' \
192.168.122.0/24 \
oifname \
enp0s7 \
counter \
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:1024-65535
nft \
-ae insert \
rule \
ip \
libvirt_network \
guest_nat \
meta \
l4proto \
tcp \
ip \
saddr \
192.168.122.0/24 \
ip \
daddr \
'!=' \
192.168.122.0/24 \
oifname \
enp0s7 \
counter \
masquerade \
to \
:1024-65535
nft \
-ae insert \
rule \
ip \
libvirt_network \
guest_nat \
oifname \
enp0s7 \
ip \
saddr \
192.168.122.0/24 \
ip \
daddr \
255.255.255.255/32 \
counter \
return
nft \
-ae insert \
rule \
ip \
libvirt_network \
guest_nat \
oifname \
enp0s7 \
ip \
saddr \
192.168.122.0/24 \
ip \
daddr \
224.0.0.0/24 \
counter \
return
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