From 8527c75281c533bdabe4a0cea442ef784aeafe46 Mon Sep 17 00:00:00 2001
From: coolsnowwolf <coolsnowwolf@gmail.com>
Date: Thu, 17 Oct 2024 16:51:29 +0800
Subject: [PATCH] base-files: ipcalc.sh: check for params before calculating
 start/end

---
 package/base-files/files/bin/ipcalc.sh | 51 +++++++++++++++++---------
 1 file changed, 34 insertions(+), 17 deletions(-)

diff --git a/package/base-files/files/bin/ipcalc.sh b/package/base-files/files/bin/ipcalc.sh
index 5d5eac3ea..6e72617e1 100755
--- a/package/base-files/files/bin/ipcalc.sh
+++ b/package/base-files/files/bin/ipcalc.sh
@@ -1,6 +1,5 @@
-#!/bin/sh
+#!/usr/bin/awk -f
 
-awk -f - $* <<EOF
 function bitcount(c) {
 	c=and(rshift(c, 1),0x55555555)+and(c,0x55555555)
 	c=and(rshift(c, 2),0x33333333)+and(c,0x33333333)
@@ -11,14 +10,20 @@ function bitcount(c) {
 }
 
 function ip2int(ip) {
-	for (ret=0,n=split(ip,a,"\."),x=1;x<=n;x++) ret=or(lshift(ret,8),a[x])
+	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;ret=and(ip,255)"."ret,ip=rshift(ip,8),x++);
+	for(;x<3;x++) {
+		ret=and(ip,255)"."ret
+		ip=rshift(ip,8)
+	}
 	return ret
 }
 
@@ -44,28 +49,40 @@ BEGIN {
 	}
 
 	network=and(ipaddr,netmask)
+	prefix=32-bitcount(compl32(netmask))
 	broadcast=or(network,compl32(netmask))
 
-	start=or(network,and(ip2int(ARGV[3]),compl32(netmask)))
-	limit=network+1
-	if (start<limit) start=limit
-
-	end=start+ARGV[4]
-	limit=or(network,compl32(netmask))-1
-	if (end>limit) end=limit
-
 	print "IP="int2ip(ipaddr)
 	print "NETMASK="int2ip(netmask)
 	print "BROADCAST="int2ip(broadcast)
 	print "NETWORK="int2ip(network)
-	print "PREFIX="32-bitcount(compl32(netmask))
+	print "PREFIX="prefix
 
 	# range calculations:
 	# ipcalc <ip> <netmask> <start> <num>
 
-	if (ARGC > 3) {
-		print "START="int2ip(start)
-		print "END="int2ip(end)
+	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)
 }
-EOF