IP rules (policy routing)

Netifd supports IP rule declarations which are required to implement policy routing.

IPv4 rules can be defined by declaring one or more sections of type rule, IPv6 rules are denoted by sections of type rule6. Both types share the same set of defined options.

A simple IPv4 rule may look like:

config rule
	option mark   '0xFF'
        option in     'lan'
	option dest   '172.16.0.0/16'
	option lookup '100'

0xFF is a fwmark to be matched
lan is the incoming logical interface name
172.16.0.0/16 is the destination subnet to match
100 is the routing table ID to use for the matched traffic

Similary, an IPv6 rule looks like:

config rule6
        option in     'vpn'
	option dest   'fdca:1234::/64'
	option action 'prohibit'

vpn is the incoming logical interface name
fdca:1234::/64 is the destination subnet to match
prohibit is a routing action to take

Name	Type	Required	Default	Description
`in`	string	no	(none)	Specifies the incoming logical interface name
`out`	string	no	(none)	Specifies the outgoing logical interface name
`src`	ip subnet	no	(none)	Specifies the source subnet to match (CIDR notation)
`dest`	ip subnet	no	(none)	Specifies the destination subnet to match (CIDR notation)
`tos`	integer	no	(none)	Specifies the TOS value to match in IP headers
`mark`	mark/mask	no	(none)	Specifies the fwmark and optionally its mask to match, e.g. `0xFF` to match mark 255 or `0x0/0x1` to match any even mark value
`suppress_prefixlength`	integer	no	(none)	Reject routing decisions that have a prefix length less than or equal to the specified value
`invert`	boolean	no	`0`	If set to `1`, the meaning of the match options is inverted
`priority`	integer	no	(incrementing)	Controls the order of the IP rules, by default the priority is auto-assigned so that they are processed in the same order they're declared in the config file
`lookup`	routing table	at least one of	(none)	The rule target is a table lookup, the ID can be either a numeric table index ranging from `0` to `65535` or a symbolic alias declared in `/etc/iproute2/rt_tables`. The special aliases `local` (`255`), `main` (`254`) and `default` (`253`) are recognized as well
`goto`	rule index			The rule target is a jump to another rule specified by its `priority` value
`action`	string			The rule target is one of the routing actions outlined in the table below

Action	Description
`prohibit`	When reaching the rule, respond with ICMP prohibited messages and abort route lookup
`unreachable`	When reaching the rule, respond with ICMP unreachable messages and abort route lookup
`blackhole`	When reaching the rule, drop packet and abort route lookup
`throw`	Stop lookup in the current routing table even if a default route exists

Route specific LAN to specific WAN.

# Use custom routing table for LAN
uci set network.lanx.ip4table="100"
uci set network.lanx.ip6table="100"
 
# Use custom routing table for WAN
uci set network.wanx.ip4table="100"
uci set network.wanx.ip6table="100"
 
# LAN to WAN rule
uci -q delete network.lanx_wanx
uci set network.lanx_wanx="rule"
uci set network.lanx_wanx.in="lanx"
uci set network.lanx_wanx.lookup="100"
 
# WAN to LAN rule
uci -q delete network.wanx_lanx
uci set network.wanx_lanx="rule"
uci set network.wanx_lanx.in="wanx"
uci set network.wanx_lanx.lookup="100"
 
# Save and apply
uci commit network
/etc/init.d/network restart

IP rules (policy routing)

Options for IP rule (rule and rule6) sections

Routing Actions

Examples

Policy-based routing