Optimized apply_mask fn

spfutil.c

@@ -37,6 +37,7 @@
 #include "advert.h"
 #include "spftrace.h"
 #include "LinuxMemoryManager/uapi_mm.h"
+#include <stdint.h>
 
 extern instance_t *instance;
 
@@ -229,11 +230,25 @@ spf_determine_multi_area_attachment(spf_info_t *spf_info,
 void
 apply_mask(char *prefix, char mask, char *str_prefix){
 
-    unsigned int binary_prefix = 0, i = 0;
+    uint32_t binary_prefix = 0;
+    uint32_t subnet_mask = 0xFFFFFFFF;
+
+    if(mask == 32){
+        strncpy(str_prefix, prefix, PREFIX_LEN);
+        str_prefix[PREFIX_LEN] = '\0';
+        return;
+    }
+    /*Convert Given IP address into binary format*/
     inet_pton(AF_INET, prefix, &binary_prefix);
     binary_prefix = htonl(binary_prefix);
-    for(; i < (32 - mask); i++)
-        UNSET_BIT(binary_prefix, i);
+
+    /*Compute Mask in binary format as well*/
+    subnet_mask = subnet_mask << (32 - mask);
+
+    /*Perform logical AND to apply mask on IP address*/
+    binary_prefix = binary_prefix & subnet_mask;
+
+    /*Convert the Final IP into string format again*/
     binary_prefix = htonl(binary_prefix);
     inet_ntop(AF_INET, &binary_prefix, str_prefix, PREFIX_LEN + 1);
     str_prefix[PREFIX_LEN] = '\0';