openwrt/package/base-files/files/bin/ipcalc.sh
Leon M. Busch-George 83bf45ea5c
package: base-files: turn error into warning
Some users have their routers configured to supply a DHCP range that
includes the local interface address.
That worked with dnsmasq because it automatically skips the local
address.

Re-enable those existing configurations for the release and hint at
possible future problems.

Signed-off-by: Leon M. Busch-George <leon@georgemail.eu>
[ wrap commit description and remove unecessary text ]
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
2023-09-19 15:38:59 +02:00

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#!/usr/bin/awk -f
function bitcount(c) {
c=and(rshift(c, 1),0x55555555)+and(c,0x55555555)
c=and(rshift(c, 2),0x33333333)+and(c,0x33333333)
c=and(rshift(c, 4),0x0f0f0f0f)+and(c,0x0f0f0f0f)
c=and(rshift(c, 8),0x00ff00ff)+and(c,0x00ff00ff)
c=and(rshift(c,16),0x0000ffff)+and(c,0x0000ffff)
return c
}
function ip2int(ip) {
ret=0
n=split(ip,a,"\\.")
for (x=1;x<=n;x++)
ret=or(lshift(ret,8),a[x])
return ret
}
function int2ip(ip,ret,x) {
ret=and(ip,255)
ip=rshift(ip,8)
for(;x<3;x++) {
ret=and(ip,255)"."ret
ip=rshift(ip,8)
}
return ret
}
function compl32(v) {
ret=xor(v, 0xffffffff)
return ret
}
BEGIN {
slpos=index(ARGV[1],"/")
if (slpos == 0) {
ipaddr=ip2int(ARGV[1])
dotpos=index(ARGV[2],".")
if (dotpos == 0)
netmask=compl32(2**(32-int(ARGV[2]))-1)
else
netmask=ip2int(ARGV[2])
} else {
ipaddr=ip2int(substr(ARGV[1],0,slpos-1))
netmask=compl32(2**(32-int(substr(ARGV[1],slpos+1)))-1)
ARGV[4]=ARGV[3]
ARGV[3]=ARGV[2]
}
network=and(ipaddr,netmask)
prefix=32-bitcount(compl32(netmask))
broadcast=or(network,compl32(netmask))
print "IP="int2ip(ipaddr)
print "NETMASK="int2ip(netmask)
print "BROADCAST="int2ip(broadcast)
print "NETWORK="int2ip(network)
print "PREFIX="prefix
# range calculations:
# ipcalc <ip> <netmask> <start> <num>
if (ARGC <= 3)
exit(0)
start=or(network,and(ip2int(ARGV[3]),compl32(netmask)))
limit=network+1
if (start<limit) start=limit
if (start==ipaddr) start=ipaddr+1
end=start+ARGV[4]
limit=or(network,compl32(netmask))-1
if (end>limit) end=limit
if (end==ipaddr) end=ipaddr-1
if (start>end) {
print "network ("int2ip(network)"/"prefix") too small" > "/dev/stderr"
exit(1)
}
if (ipaddr > start && ipaddr < end) {
print "warning: ipaddr inside range - this might not be supported in future releases of Openwrt" > "/dev/stderr"
}
print "START="int2ip(start)
print "END="int2ip(end)
}