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
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
#!/bin/bash
# dhclient-script for Linux. Dan Halbert, March, 1997.
# Updated for Linux 2.[12] by Brian J. Murrell, January 1999.
# No guarantees about this. I'm a novice at the details of Linux
# networking.
# Notes:
# 0. This script is based on the netbsd script supplied with dhcp-970306.
# 1. ifconfig down apparently deletes all relevant routes and flushes
# the arp cache, so this doesn't need to be done explicitly.
# 2. The alias address handling here has not been tested AT ALL.
# I'm just going by the doc of modern Linux ip aliasing, which uses
# notations like eth0:0, eth0:1, for each alias.
# 3. I have to calculate the network address, and calculate the broadcast
# address if it is not supplied. This might be much more easily done
# by the dhclient C code, and passed on.
# 4. TIMEOUT not tested. ping has a flag I don't know, and I'm suspicious
# of the $1 in its args.
make_resolv_conf() {
if [ "x$new_domain_name" != x ] && [ x"$new_domain_name_servers" != x ]; then
echo search $new_domain_name >/etc/resolv.conf
chmod 644 /etc/resolv.conf
for nameserver in $new_domain_name_servers; do
echo nameserver $nameserver >>/etc/resolv.conf
done
fi
}
# Must be used on exit. Invokes the local dhcp client exit hooks, if any.
exit_with_hooks() {
exit_status=$1
if [ -f /etc/dhclient-exit-hooks ]; then
. /etc/dhclient-exit-hooks
fi
# probably should do something with exit status of the local script
exit $exit_status
}
# Invoke the local dhcp client enter hooks, if they exist.
if [ -f /etc/dhclient-enter-hooks ]; then
exit_status=0
. /etc/dhclient-enter-hooks
# allow the local script to abort processing of this state
# local script must set exit_status variable to nonzero.
if [ $exit_status -ne 0 ]; then
exit $exit_status
fi
fi
release=`uname -r`
release=`expr $release : '\(.*\)\..*'`
relminor=`echo $release |sed -e 's/[0-9]*\.\([0-9][0-9]*\)\(\..*\)*$/\1/'`
relmajor=`echo $release |sed -e 's/\([0-9][0-9]*\)\..*$/\1/'`
if [ x$new_broadcast_address != x ]; then
new_broadcast_arg="broadcast $new_broadcast_address"
fi
if [ x$old_broadcast_address != x ]; then
old_broadcast_arg="broadcast $old_broadcast_address"
fi
if [ x$new_subnet_mask != x ]; then
new_subnet_arg="netmask $new_subnet_mask"
fi
if [ x$old_subnet_mask != x ]; then
old_subnet_arg="netmask $old_subnet_mask"
fi
if [ x$alias_subnet_mask != x ]; then
alias_subnet_arg="netmask $alias_subnet_mask"
fi
if [ x$reason = xMEDIUM ]; then
# Linux doesn't do mediums (ok, ok, media).
exit_with_hooks 0
fi
if [ x$reason = xPREINIT ]; then
if [ x$alias_ip_address != x ]; then
# Bring down alias interface. Its routes will disappear too.
ifconfig $interface:0- inet 0
fi
if [ $relmajor -lt 2 ] || ( [ $relmajor -eq 2 ] && [ $relminor -eq 0 ] )
then
ifconfig $interface inet 0.0.0.0 netmask 0.0.0.0 \
broadcast 255.255.255.255 up
# Add route to make broadcast work. Do not omit netmask.
route add default dev $interface netmask 0.0.0.0
else
ifconfig $interface 0 up
fi
# We need to give the kernel some time to get the interface up.
sleep 1
exit_with_hooks 0
fi
if [ x$reason = xARPCHECK ] || [ x$reason = xARPSEND ]; then
exit_with_hooks 0
fi
if [ x$reason = xBOUND ] || [ x$reason = xRENEW ] || \
[ x$reason = xREBIND ] || [ x$reason = xREBOOT ]; then
current_hostname=`hostname`
if [ x$current_hostname = x ] || \
[ x$current_hostname = x$old_host_name ]; then
if [ x$current_hostname = x ] || \
[ x$new_host_name != x$old_host_name ]; then
hostname $new_host_name
fi
fi
if [ x$old_ip_address != x ] && [ x$alias_ip_address != x ] && \
[ x$alias_ip_address != x$old_ip_address ]; then
# Possible new alias. Remove old alias.
ifconfig $interface:0- inet 0
fi
if [ x$old_ip_address != x ] && [ x$old_ip_address != x$new_ip_address ]; then
# IP address changed. Bringing down the interface will delete all routes,
# and clear the ARP cache.
ifconfig $interface inet 0 down
fi
if [ x$old_ip_address = x ] || [ x$old_ip_address != x$new_ip_address ] || \
[ x$reason = xBOUND ] || [ x$reason = xREBOOT ]; then
ifconfig $interface inet $new_ip_address $new_subnet_arg \
$new_broadcast_arg
# Add a network route to the computed network address.
if [ $relmajor -lt 2 ] || \
( [ $relmajor -eq 2 ] && [ $relminor -eq 0 ] ); then
route add -net $new_network_number $new_subnet_arg dev $interface
fi
for router in $new_routers; do
route add default gw $router
done
fi
if [ x$new_ip_address != x$alias_ip_address ] && [ x$alias_ip_address != x ];
then
ifconfig $interface:0- inet 0
ifconfig $interface:0 inet $alias_ip_address $alias_subnet_arg
route add -host $alias_ip_address $interface:0
fi
make_resolv_conf
exit_with_hooks 0
fi
if [ x$reason = xEXPIRE ] || [ x$reason = xFAIL ] || [ x$reason = xRELEASE ] \
|| [ x$reason = xSTOP ]; then
if [ x$alias_ip_address != x ]; then
# Turn off alias interface.
ifconfig $interface:0- inet 0
fi
if [ x$old_ip_address != x ]; then
# Shut down interface, which will delete routes and clear arp cache.
ifconfig $interface inet 0 down
fi
if [ x$alias_ip_address != x ]; then
ifconfig $interface:0 inet $alias_ip_address $alias_subnet_arg
route add -host $alias_ip_address $interface:0
fi
exit_with_hooks 0
fi
if [ x$reason = xTIMEOUT ]; then
if [ x$alias_ip_address != x ]; then
ifconfig $interface:0- inet 0
fi
ifconfig $interface inet $new_ip_address $new_subnet_arg \
$new_broadcast_arg
set $new_routers
############## what is -w in ping?
if ping -q -c 1 $1; then
if [ x$new_ip_address != x$alias_ip_address ] && \
[ x$alias_ip_address != x ]; then
ifconfig $interface:0 inet $alias_ip_address $alias_subnet_arg
route add -host $alias_ip_address dev $interface:0
fi
if [ $relmajor -lt 2 ] || \
( [ $relmajor -eq 2 ] && [ $relminor -eq 0 ] ); then
route add -net $new_network_number
fi
for router in $new_routers; do
route add default gw $router
done
make_resolv_conf
exit_with_hooks 0
fi
ifconfig $interface inet 0 down
exit_with_hooks 1
fi
exit_with_hooks 0
|
