2 # ipnext: increment a dotted quad IP address
16 # check that we have a dotted quad
18 if expr match "X$n" 'X[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*$' >/dev/null
22 echo "\"$n\" isn't a dotted quad" >&2
26 # break out fields of dotted quad
27 q1=`expr match "X$n" 'X\([0-9][0-9]*\)\.[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*$'`
28 q2=`expr match "X$n" 'X[0-9][0-9]*\.\([0-9][0-9]*\)\.[0-9][0-9]*\.[0-9][0-9]*$'`
29 q3=`expr match "X$n" 'X[0-9][0-9]*\.[0-9][0-9]*\.\([0-9][0-9]*\)\.[0-9][0-9]*$'`
30 q4=`expr match "X$n" 'X[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\.\([0-9][0-9]*\)$'`
32 # increment by 7.123.59.229 (arbitrary)
39 q1=`expr '(' $q1 + $q2 / 256 ')' % 256`
40 q2=`expr '(' $q2 + $q3 / 256 ')' % 256`
41 q3=`expr '(' $q3 + $q4 / 256 ')' % 256`
44 # around again if unroutable address
47 10.*|192.168.*|172.16.[0-9].*|172.16.1[0-5].*|127.*)