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nft: POSTNAT mode support

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bol-van 2023-11-07 12:04:26 +03:00
parent 22b6ee4ad5
commit f03bb1747f
1 changed files with 30 additions and 4 deletions
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34
common/nft.sh
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@ -37,6 +37,11 @@ nft_set_exists()
# $1 - set name # $1 - set name
nft -t list set inet $ZAPRET_NFT_TABLE $1 2>/dev/null >/dev/null nft -t list set inet $ZAPRET_NFT_TABLE $1 2>/dev/null >/dev/null
} }
nft_flush_chain()
{
# $1 - chain name
nft flush chain inet $ZAPRET_NFT_TABLE $1
}
nft_del_all_chains_from_table() nft_del_all_chains_from_table()
{ {
@ -65,6 +70,7 @@ nft_create_chains()
{ {
# NOTE : postrouting hook has priority 99 to hook packets with original source but NATed destination # NOTE : postrouting hook has priority 99 to hook packets with original source but NATed destination
# NOTE : prerouting hook has priority -99 for the same reason # NOTE : prerouting hook has priority -99 for the same reason
# NOTE : postnat is intended for hooks after NAT. many undersired things can happen. use with care. to activate set env POSTNAT=1
cat << EOF | nft -f - cat << EOF | nft -f -
add chain inet $ZAPRET_NFT_TABLE dnat_output { type nat hook output priority -101; } add chain inet $ZAPRET_NFT_TABLE dnat_output { type nat hook output priority -101; }
flush chain inet $ZAPRET_NFT_TABLE dnat_output flush chain inet $ZAPRET_NFT_TABLE dnat_output
@ -82,13 +88,24 @@ cat << EOF | nft -f -
add rule inet $ZAPRET_NFT_TABLE localnet_protect ip daddr 127.0.0.0/8 drop comment "route_localnet remote access protection" add rule inet $ZAPRET_NFT_TABLE localnet_protect ip daddr 127.0.0.0/8 drop comment "route_localnet remote access protection"
add rule inet $ZAPRET_NFT_TABLE input iif != lo jump localnet_protect add rule inet $ZAPRET_NFT_TABLE input iif != lo jump localnet_protect
add chain inet $ZAPRET_NFT_TABLE postrouting { type filter hook postrouting priority 99; } add chain inet $ZAPRET_NFT_TABLE postrouting { type filter hook postrouting priority 99; }
add chain inet $ZAPRET_NFT_TABLE prerouting { type filter hook prerouting priority -99; }
flush chain inet $ZAPRET_NFT_TABLE postrouting flush chain inet $ZAPRET_NFT_TABLE postrouting
add chain inet $ZAPRET_NFT_TABLE postnat { type filter hook postrouting priority 101; }
flush chain inet $ZAPRET_NFT_TABLE postnat
add chain inet $ZAPRET_NFT_TABLE prerouting { type filter hook prerouting priority -99; }
flush chain inet $ZAPRET_NFT_TABLE prerouting
add chain inet $ZAPRET_NFT_TABLE predefrag { type filter hook output priority -401; }
flush chain inet $ZAPRET_NFT_TABLE predefrag
add rule inet $ZAPRET_NFT_TABLE predefrag mark and $DESYNC_MARK !=0 ip frag-off != 0 notrack comment "do not track nfqws generated ipfrag packets to avoid nat tampering and defragmentation"
add rule inet $ZAPRET_NFT_TABLE predefrag mark and $DESYNC_MARK !=0 exthdr frag exists notrack comment "do not track nfqws generated ipfrag packets to avoid nat tampering and defragmentation"
add set inet $ZAPRET_NFT_TABLE lanif { type ifname; } add set inet $ZAPRET_NFT_TABLE lanif { type ifname; }
add set inet $ZAPRET_NFT_TABLE wanif { type ifname; } add set inet $ZAPRET_NFT_TABLE wanif { type ifname; }
add set inet $ZAPRET_NFT_TABLE wanif6 { type ifname; } add set inet $ZAPRET_NFT_TABLE wanif6 { type ifname; }
add map inet $ZAPRET_NFT_TABLE link_local { type ifname : ipv6_addr; } add map inet $ZAPRET_NFT_TABLE link_local { type ifname : ipv6_addr; }
EOF EOF
[ -n "$POSTNAT_ALL" ] && {
nft_flush_chain predefrag
nft_add_rule predefrag mark and $DESYNC_MARK !=0 notrack comment \"do not track nfqws generated packets to avoid nat tampering and defragmentation\"
}
# unfortunately this approach breaks udp desync of the connection initiating packet (new, first one) # unfortunately this approach breaks udp desync of the connection initiating packet (new, first one)
# however without notrack ipfrag will not work # however without notrack ipfrag will not work
# postrouting priority : 99 - before srcnat, 101 - after srcnat # postrouting priority : 99 - before srcnat, 101 - after srcnat
@ -108,7 +125,9 @@ cat << EOF | nft -f - 2>/dev/null
delete chain inet $ZAPRET_NFT_TABLE forward delete chain inet $ZAPRET_NFT_TABLE forward
delete chain inet $ZAPRET_NFT_TABLE input delete chain inet $ZAPRET_NFT_TABLE input
delete chain inet $ZAPRET_NFT_TABLE postrouting delete chain inet $ZAPRET_NFT_TABLE postrouting
delete chain inet $ZAPRET_NFT_TABLE postnat
delete chain inet $ZAPRET_NFT_TABLE prerouting delete chain inet $ZAPRET_NFT_TABLE prerouting
delete chain inet $ZAPRET_NFT_TABLE predefrag
delete chain inet $ZAPRET_NFT_TABLE flow_offload delete chain inet $ZAPRET_NFT_TABLE flow_offload
delete chain inet $ZAPRET_NFT_TABLE localnet_protect delete chain inet $ZAPRET_NFT_TABLE localnet_protect
EOF EOF
@ -425,7 +444,14 @@ nft_fw_tpws()
nft_fw_tpws4 "$1" $3 nft_fw_tpws4 "$1" $3
nft_fw_tpws6 "$2" $3 nft_fw_tpws6 "$2" $3
} }
get_postchain()
{
if [ "$POSTNAT" = 1 -o "$POSTNAT_ALL" = 1 ] ; then
echo -n postnat
else
echo -n postrouting
fi
}
_nft_fw_nfqws_post4() _nft_fw_nfqws_post4()
{ {
# $1 - filter ipv4 # $1 - filter ipv4
@ -436,7 +462,7 @@ _nft_fw_nfqws_post4()
local filter="$1" port="$2" rule local filter="$1" port="$2" rule
nft_print_op "$filter" "nfqws postrouting (qnum $port)" 4 nft_print_op "$filter" "nfqws postrouting (qnum $port)" 4
rule="${3:+oifname @wanif }$filter ip daddr != @nozapret" rule="${3:+oifname @wanif }$filter ip daddr != @nozapret"
nft_add_rule postrouting $rule queue num $port bypass nft_add_rule $(get_postchain) $rule queue num $port bypass
nft_add_nfqws_flow_exempt_rule "$rule" nft_add_nfqws_flow_exempt_rule "$rule"
} }
} }
@ -450,7 +476,7 @@ _nft_fw_nfqws_post6()
local filter="$1" port="$2" rule local filter="$1" port="$2" rule
nft_print_op "$filter" "nfqws postrouting (qnum $port)" 6 nft_print_op "$filter" "nfqws postrouting (qnum $port)" 6
rule="${3:+oifname @wanif6 }$filter ip6 daddr != @nozapret6" rule="${3:+oifname @wanif6 }$filter ip6 daddr != @nozapret6"
nft_add_rule postrouting $rule queue num $port bypass nft_add_rule $(get_postchain) $rule queue num $port bypass
nft_add_nfqws_flow_exempt_rule "$rule" nft_add_nfqws_flow_exempt_rule "$rule"
} }
} }