blob: 483910a16658c562cb72cee5a3cbac67c23abb77 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.networking.nat;
mkDest = externalIP:
if externalIP == null
then "masquerade"
else "snat ${externalIP}";
dest = mkDest cfg.externalIP;
destIPv6 = mkDest cfg.externalIPv6;
toNftSet = list: concatStringsSep ", " list;
toNftRange = ports: replaceStrings [ ":" ] [ "-" ] (toString ports);
ifaceSet = toNftSet (map (x: ''"${x}"'') cfg.internalInterfaces);
ipSet = toNftSet cfg.internalIPs;
ipv6Set = toNftSet cfg.internalIPv6s;
oifExpr = optionalString (cfg.externalInterface != null) ''oifname "${cfg.externalInterface}"'';
# Whether given IP (plus optional port) is an IPv6.
isIPv6 = ip: length (lib.splitString ":" ip) > 2;
splitIPPorts = IPPorts:
let
matchIP = if isIPv6 IPPorts then "[[]([0-9a-fA-F:]+)[]]" else "([0-9.]+)";
m = builtins.match "${matchIP}:([0-9-]+)" IPPorts;
in
{
IP = if m == null then throw "bad ip:ports `${IPPorts}'" else elemAt m 0;
ports = if m == null then throw "bad ip:ports `${IPPorts}'" else elemAt m 1;
};
mkTable = { ipVer, dest, ipSet, forwardPorts, dmzHost }:
let
# nftables does not support both port and port range as values in a dnat map.
# e.g. "dnat th dport map { 80 : 10.0.0.1 . 80, 443 : 10.0.0.2 . 900-1000 }"
# So we split them.
fwdPorts = filter (x: length (splitString "-" x.destination) == 1) forwardPorts;
fwdPortsRange = filter (x: length (splitString "-" x.destination) > 1) forwardPorts;
# nftables maps for port forward
# l4proto . dport : addr . port
toFwdMap = forwardPorts: toNftSet (map
(fwd:
with (splitIPPorts fwd.destination);
"${fwd.proto} . ${toNftRange fwd.sourcePort} : ${IP} . ${ports}"
)
forwardPorts);
fwdMap = toFwdMap fwdPorts;
fwdRangeMap = toFwdMap fwdPortsRange;
# nftables maps for port forward loopback dnat
# daddr . l4proto . dport : addr . port
toFwdLoopDnatMap = forwardPorts: toNftSet (concatMap
(fwd: map
(loopbackip:
with (splitIPPorts fwd.destination);
"${loopbackip} . ${fwd.proto} . ${toNftRange fwd.sourcePort} : ${IP} . ${ports}"
)
fwd.loopbackIPs)
forwardPorts);
fwdLoopDnatMap = toFwdLoopDnatMap fwdPorts;
fwdLoopDnatRangeMap = toFwdLoopDnatMap fwdPortsRange;
# nftables set for port forward loopback snat
# daddr . l4proto . dport
fwdLoopSnatSet = toNftSet (map
(fwd:
with (splitIPPorts fwd.destination);
"${IP} . ${fwd.proto} . ${ports}"
)
forwardPorts);
in
''
chain pre {
type nat hook prerouting priority dstnat;
${optionalString (fwdMap != "") ''
iifname "${cfg.externalInterface}" dnat meta l4proto . th dport map { ${fwdMap} } comment "port forward"
''}
${optionalString (fwdRangeMap != "") ''
iifname "${cfg.externalInterface}" dnat meta l4proto . th dport map { ${fwdRangeMap} } comment "port forward"
''}
${optionalString (fwdLoopDnatMap != "") ''
dnat ${ipVer} daddr . meta l4proto . th dport map { ${fwdLoopDnatMap} } comment "port forward loopback from other hosts behind NAT"
''}
${optionalString (fwdLoopDnatRangeMap != "") ''
dnat ${ipVer} daddr . meta l4proto . th dport map { ${fwdLoopDnatRangeMap} } comment "port forward loopback from other hosts behind NAT"
''}
${optionalString (dmzHost != null) ''
iifname "${cfg.externalInterface}" dnat ${dmzHost} comment "dmz"
''}
}
chain post {
type nat hook postrouting priority srcnat;
${optionalString (ifaceSet != "") ''
iifname { ${ifaceSet} } ${oifExpr} ${dest} comment "from internal interfaces"
''}
${optionalString (ipSet != "") ''
${ipVer} saddr { ${ipSet} } ${oifExpr} ${dest} comment "from internal IPs"
''}
${optionalString (fwdLoopSnatSet != "") ''
iifname != "${cfg.externalInterface}" ${ipVer} daddr . meta l4proto . th dport { ${fwdLoopSnatSet} } masquerade comment "port forward loopback snat"
''}
}
chain out {
type nat hook output priority mangle;
${optionalString (fwdLoopDnatMap != "") ''
dnat ${ipVer} daddr . meta l4proto . th dport map { ${fwdLoopDnatMap} } comment "port forward loopback from the host itself"
''}
${optionalString (fwdLoopDnatRangeMap != "") ''
dnat ${ipVer} daddr . meta l4proto . th dport map { ${fwdLoopDnatRangeMap} } comment "port forward loopback from the host itself"
''}
}
'';
in
{
config = mkIf (config.networking.nftables.enable && cfg.enable) {
assertions = [
{
assertion = cfg.extraCommands == "";
message = "extraCommands is incompatible with the nftables based nat module: ${cfg.extraCommands}";
}
{
assertion = cfg.extraStopCommands == "";
message = "extraStopCommands is incompatible with the nftables based nat module: ${cfg.extraStopCommands}";
}
{
assertion = config.networking.nftables.rulesetFile == null;
message = "networking.nftables.rulesetFile conflicts with the nat module";
}
];
networking.nftables.ruleset = ''
table ip nixos-nat {
${mkTable {
ipVer = "ip";
inherit dest ipSet;
forwardPorts = filter (x: !(isIPv6 x.destination)) cfg.forwardPorts;
inherit (cfg) dmzHost;
}}
}
${optionalString cfg.enableIPv6 ''
table ip6 nixos-nat {
${mkTable {
ipVer = "ip6";
dest = destIPv6;
ipSet = ipv6Set;
forwardPorts = filter (x: isIPv6 x.destination) cfg.forwardPorts;
dmzHost = null;
}}
}
''}
'';
networking.firewall.extraForwardRules = optionalString config.networking.firewall.filterForward ''
${optionalString (ifaceSet != "") ''
iifname { ${ifaceSet} } ${oifExpr} accept comment "from internal interfaces"
''}
${optionalString (ipSet != "") ''
ip saddr { ${ipSet} } ${oifExpr} accept comment "from internal IPs"
''}
${optionalString (ipv6Set != "") ''
ip6 saddr { ${ipv6Set} } ${oifExpr} accept comment "from internal IPv6s"
''}
'';
};
}
|