157 lines
5.4 KiB
Bash
157 lines
5.4 KiB
Bash
#!/bin/sh
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# dhclient-script for Linux. Dan Halbert, March, 1997.
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# No guarantees about this. I'm a novice at the details of Linux
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# networking.
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# Notes:
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# 0. This script is based on the netbsd script supplied with dhcp-970306.
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# 1. ifconfig down apparently deletes all relevant routes and flushes
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# the arp cache, so this doesn't need to be done explicitly.
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# 2. The alias address handling here has not been tested AT ALL.
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# I'm just going by the doc of modern Linux ip aliasing, which uses
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# notations like eth0:0, eth0:1, for each alias.
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# 3. I have to calculate the network address, and calculate the broadcast
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# address if it is not supplied. This might be much more easily done
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# by the dhclient C code, and passed on.
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# 4. TIMEOUT not tested. ping has a flag I don't know, and I'm suspicious
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# of the $1 in its args.
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############################################################################
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# This horror, which depends on bash, does a bitwise and of the ip
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# address and the network mask to produce the network address.
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eval `echo $new_ip_address $new_subnet_mask | sed -e 's/\([0-9]\+\).\([0-9]\+\).\([0-9]\+\).\([0-9]\+\) \([0-9]\+\).\([0-9]\+\).\([0-9]\+\).\([0-9]\+\)/new_network_address="$[\1\&\5].$[\2\&\6].$[\3\&\7].$[4\&\8]"/'`
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# A similar horror to calculate the broadcast address if it's not given.
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if [ x$new_broadcast_address = x ]; then
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eval `echo $new_ip_address $new_subnet_mask | sed -e 's/\([0-9]\+\).\([0-9]\+\).\([0-9]\+\).\([0-9]\+\) \([0-9]\+\).\([0-9]\+\).\([0-9]\+\).\([0-9]\+\)/new_broadcast_address="$[(\1\|~\5)\&255].$[(\2\|~\6)\&255].$[(\3\|~\7)\&255].$[(4\|~\8)\&255]"/'`
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fi
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if [ x$new_broadcast_address != x ]; then
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new_broadcast_arg="broadcast $new_broadcast_address"
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fi
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if [ x$old_broadcast_address != x ]; then
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old_broadcast_arg="broadcast $old_broadcast_address"
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fi
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if [ x$new_subnet_mask != x ]; then
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new_subnet_arg="netmask $new_subnet_mask"
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fi
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if [ x$old_subnet_mask != x ]; then
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old_subnet_arg="netmask $old_subnet_mask"
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fi
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if [ x$alias_subnet_mask != x ]; then
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alias_subnet_arg="netmask $alias_subnet_mask"
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fi
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if [ x$reason = xMEDIUM ]; then
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# Linux doesn't do mediums (ok, ok, media).
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exit 0
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fi
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if [ x$reason = xPREINIT ]; then
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if [ x$alias_ip_address != x ]; then
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# Bring down alias interface. Its routes will disappear too.
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ifconfig $interface:0- inet 0
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fi
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ifconfig $interface inet 0.0.0.0 netmask 0.0.0.0 \
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broadcast 255.255.255.255 up
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# Add route to make broadcast work. Do not omit netmask.
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route add default dev $interface netmask 0.0.0.0
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exit 0
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fi
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if [ x$reason = xARPCHECK ] || [ x$reason = xARPSEND ]; then
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exit 0;
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fi
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if [ x$reason = xBOUND ] || [ x$reason = xRENEW ] || \
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[ x$reason = xREBIND ] || [ x$reason = xREBOOT ]; then
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if [ x$old_ip_address != x ] && [ x$alias_ip_address != x ] && \
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[ x$alias_ip_address != x$old_ip_address ]; then
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# Possible new alias. Remove old alias.
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ifconfig $interface:0- inet 0
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fi
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if [ x$old_ip_address != x ] && [ x$old_ip_address != x$new_ip_address ]; then
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# IP address changed. Bringing down the interface will delete all routes,
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# and clear the ARP cache.
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ifconfig $interface inet down
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fi
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if [ x$old_ip_address = x ] || [ x$old_ip_address != x$new_ip_address ] || \
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[ x$reason = xBOUND ] || [ x$reason = xREBOOT ]; then
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ifconfig $interface inet $new_ip_address $new_subnet_arg \
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$new_broadcast_arg
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# Add a network route to the computed network address.
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route add -net $new_network_address $new_subnet_arg dev $interface
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for router in $new_routers; do
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route add default gw $router
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done
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fi
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if [ x$new_ip_address != x$alias_ip_address ] && [ x$alias_ip_address != x ];
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then
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ifconfig $interface:0- inet 0
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ifconfig $interface:0 inet $alias_ip_address $alias_subnet_arg
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route add -host $alias_ip_address $interface:0
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fi
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echo domain $new_domain_name >/etc/resolv.conf
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for nameserver in $new_domain_name_servers; do
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echo nameserver $nameserver >>/etc/resolv.conf
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done
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exit 0
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fi
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if [ x$reason = xEXPIRE ] || [ x$reason = xFAIL ]; then
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if [ x$alias_ip_address != x ]; then
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# Turn off alias interface.
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ifconfig $interface:0- inet 0
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fi
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if [ x$old_ip_address != x ]; then
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# Shut down interface, which will delete routes and clear arp cache.
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ifconfig $interface inet down
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fi
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if [ x$alias_ip_address != x ]; then
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ifconfig $interface:0 inet $alias_ip_address $alias_subnet_arg
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route add -host $alias_ip_address $interface:0
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fi
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exit 0
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fi
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if [ x$reason = xTIMEOUT ]; then
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if [ x$alias_ip_address != x ]; then
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ifconfig $interface:0- inet 0
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fi
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ifconfig $interface inet $new_ip_address $new_subnet_arg \
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$new_broadcast_arg
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set $new_routers
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############## what is -w in ping?
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if ping -q -c 1 -w 1 $1; then
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if [ x$new_ip_address != x$alias_ip_address ] && \
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[ x$alias_ip_address != x ]; then
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ifconfig $interface:0 inet $alias_ip_address $alias_subnet_arg
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route add -host $alias_ip_address dev $interface:0
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fi
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route add -net $new_network_address
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for router in $new_routers; do
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route add default gw $router
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done
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echo domain $new_domain_name >/etc/resolv.conf.std
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for nameserver in $new_domain_name_servers; do
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echo nameserver $nameserver >>/etc/resolv.conf.std
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done
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if [ -f /etc/resolv.conf ]; then
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rm -f /etc/resolv.conf
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ln /etc/resolv.conf.std /etc/resolv.conf
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fi
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exit 0
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fi
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ifconfig $interface inet down
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exit 1
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fi
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exit 0
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