From 71e6651c01362841443ded86c459772f1dbe59b6 Mon Sep 17 00:00:00 2001
From: bolvan <k@vodka.home.kg>
Date: Wed, 10 Apr 2019 12:05:49 +0300
Subject: [PATCH] ip2net cosmetic fixes
---
ip2net/ip2net.c | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)
diff --git a/ip2net/ip2net.c b/ip2net/ip2net.c
index 63c2dae..b2c6816 100644
--- a/ip2net/ip2net.c
+++ b/ip2net/ip2net.c
@@ -12,6 +12,10 @@
// minimum subnet fill percent is PCTMULT/PCTDIV (for example 3/4)
#define PCTMULT 3
#define PCTDIV 4
+// subnet search range in "zero bit count"
+// means search start from /(32-ZCT_MAX) to /(32-ZCT_MIN)
+#define ZCT_MAX 10
+#define ZCT_MIN 2
typedef unsigned int uint;
typedef unsigned char uchar;
@@ -33,7 +37,7 @@ uint mask_from_bitcount(uint zct)
// make presorted array unique. return number of unique items.
// 1,1,2,3,3,0,0,0 (ct=8) => 1,2,3,0 (ct=4)
-uint unique_uint(uint *pu,uint ct)
+uint unique(uint *pu,uint ct)
{
uint i,j,u;
for(i=j=0 ; j<ct ; i++)
@@ -85,37 +89,36 @@ int main()
}
gnu_quicksort(iplist,ipct,sizeof(*iplist),ucmp,NULL);
- ipct = unique_uint(iplist,ipct);
+ ipct = unique(iplist,ipct);
while(pos<ipct)
{
- uchar subnet_ok=0;
uint mask,ip_start,ip_end,ip_ct,subnet_ct,pos_end;
- for(zct=10, pos_end=pos+1 ; zct>=2 ; zct--)
+
+ // find largest possible network with enough ip coverage
+ for(zct=ZCT_MAX ; zct>=ZCT_MIN ; zct--)
{
mask = mask_from_bitcount(zct);
ip_start = iplist[pos] & mask;
subnet_ct = ~mask+1;
- if (iplist[pos]>(ip_start+subnet_ct*(PCTDIV-PCTMULT)/PCTDIV)) continue;
+ if (iplist[pos]>(ip_start+subnet_ct*(PCTDIV-PCTMULT)/PCTDIV))
+ continue; // ip is higher than (1-PCT). definitely coverage is not enough. skip searching
ip_end = ip_start | ~mask;
- for(p=pos, ip_ct=0 ; p<ipct && iplist[p]<=ip_end; p++) ip_ct++;
+ for(p=pos, ip_ct=0 ; p<ipct && iplist[p]<=ip_end; p++) ip_ct++; // count ips within subnet range
if (ip_ct>=(subnet_ct*PCTMULT/PCTDIV))
{
- subnet_ok=1;
- pos_end = p;
- break;
+ // network found
+ pos_end = p;
+ break;
}
}
- if (!subnet_ok) zct=0,ip_start=iplist[pos];
+ if (zct<ZCT_MIN) zct=0, ip_start=iplist[pos], pos_end=pos+1; // network not found, use single ip
u1 = ip_start>>24;
u2 = (ip_start>>16) & 0xFF;
u3 = (ip_start>>8) & 0xFF;
u4 = ip_start & 0xFF;
- if (zct)
- printf("%u.%u.%u.%u/%u\n",u1,u2,u3,u4,32-zct);
- else
- printf("%u.%u.%u.%u\n",u1,u2,u3,u4);
+ printf(zct ? "%u.%u.%u.%u/%u\n" : "%u.%u.%u.%u\n", u1, u2, u3, u4, 32-zct);
pos = pos_end;
}