IPROUTE(3) Library Functions Manual IPROUTE(3)
NAME
iproute - Internet route table manager
SYNOPSIS
bind -a #P /net
/net/iproute
/net/ipifc
DESCRIPTION
The iproute device allows the specification of routes for families of IP addresses. It maintains a kernel-resident routing table for IP
addresses used by TCP, IL and UDP. Each route consists of a destination IP address, an IP mask, and an IP gateway address. Every packet
sent by the system is routed according to the route table. An address matches the route table entry when a packet's destination address
matches the table destination address under the mask. When a match is found, the packet is sent to the gateway IP address. If there is no
match, the packet is sent with the original destination address. If there are several matches, the one whose mask has the fewest leading
zeros is chosen. (Because of the definition of IP masks, this mask preserves the largest portion of the address and is therefore the most
specific.) This is forced by storing the routes in decreasing number of ones order and returning the first match. The default gateway has
no ones in the mask and is thus the last matched.
Reading iproute reports the current routes entered in the table. Writing control messages to iproute edits the table. Route entries are
made by writing a string of format
add ipdest mask ipgateway
Entries are deleted by writing a string of format
delete ipdest mask
The whole table can be cleared by writing the string
For example, to install a gateway address to accept all IP packets from a machine:
% echo 'add 0.0.0.0 0.0.0.0 131.107.1.5' > /net/iproute
% cat /net/iproute
0.0.0.0 & 0.0.0.0 -> 131.107.1.5
Reading ipifc reports the current IP interfaces being used, one line per interface, showing the device, the maximum transfer unit, the
local address, the network mask, and the network address.
SOURCE
/sys/src/9/port/deviproute.c
SEE ALSO
ip(3), ipconfig(8)
IPROUTE(3)