From 0af11f97b582754df36b588e04fd9d9377b50823 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Mon, 11 Feb 2019 23:26:57 +0100
Subject: libip: replace v4parsecidr() with new parseipandmask()

we want to accept V4 subnets in CIDR notation consistently which
means we need to interpret the mask in context of the IP address.
so parseipmask() now has an additional v4 flag argument which
offsets the prefixlength by 96 so a /24 will be interpreted
as a /120.

parseipandmask() is the new function which handles this automatically
depending on the ip address type.

v4parsecidr() is now obsolete.
---
 sys/src/libip/parseip.c | 38 +++++++++++++-------------------------
 1 file changed, 13 insertions(+), 25 deletions(-)

(limited to 'sys/src/libip/parseip.c')

diff --git a/sys/src/libip/parseip.c b/sys/src/libip/parseip.c
index 9f5d5dac7..757716770 100644
--- a/sys/src/libip/parseip.c
+++ b/sys/src/libip/parseip.c
@@ -122,7 +122,7 @@ parseip(uchar *to, char *from)
  *  style
  */
 vlong
-parseipmask(uchar *to, char *from)
+parseipmask(uchar *to, char *from, int v4)
 {
 	int i, w;
 	vlong x;
@@ -133,6 +133,8 @@ parseipmask(uchar *to, char *from)
 		i = atoi(from+1);
 		if(i < 0)
 			i = 0;
+		if(i <= 32 && v4)
+			i += 96;
 		if(i > 128)
 			i = 128;
 		w = i;
@@ -141,7 +143,6 @@ parseipmask(uchar *to, char *from)
 			*p++ = 0xff;
 		if(i > 0)
 			*p = ~((1<<(8-i))-1);
-		x = nhgetl(to+IPv4off);
 		/*
 		 * identify as ipv6 if the mask is inexpressible as a v4 mask
 		 * (because it has too few mask bits).  Arguably, we could
@@ -149,6 +150,7 @@ parseipmask(uchar *to, char *from)
 		 */
 		if (w < 8*(IPaddrlen-IPv4addrlen))
 			return 6;
+		x = nhgetl(to+IPv4off);
 	} else {
 		/* as a straight v4 bit mask */
 		x = parseip(to, from);
@@ -160,29 +162,15 @@ parseipmask(uchar *to, char *from)
 	return x;
 }
 
-/*
- *  parse a v4 ip address/mask in cidr format
- */
-char*
-v4parsecidr(uchar *addr, uchar *mask, char *from)
+vlong
+parseipandmask(uchar *ip, uchar *mask, char *ipstr, char *maskstr)
 {
-	int i;
-	char *p;
-	uchar *a;
-
-	p = v4parseip(addr, from);
+	vlong x;
 
-	if(*p == '/'){
-		/* as a number of prefix bits */
-		i = strtoul(p+1, &p, 0);
-		if(i > 32)
-			i = 32;
-		memset(mask, 0, IPv4addrlen);
-		for(a = mask; i >= 8; i -= 8)
-			*a++ = 0xff;
-		if(i > 0)
-			*a = ~((1<<(8-i))-1);
-	} else 
-		memcpy(mask, defmask(addr), IPv4addrlen);
-	return p;
+	x = parseip(ip, ipstr);
+	if(x == -1)
+		return -1;
+	if(maskstr == nil || parseipmask(mask, maskstr, memcmp(ip, v4prefix, IPv4off) == 0) == -1)
+		memset(mask, 0xff, IPaddrlen);
+	return x;
 }
-- 
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