CI: Add warning exemptions for Sun C (suncc-5.14) on Solaris 10

[tcpdump] / checksum.c

diff --git a/checksum.c b/checksum.c
index c5025082975322671ddb80f758fda344fa0054b1..bb07664dcec7962ec70bc933d8bcd14af176524c 100644 (file)
--- a/checksum.c
+++ b/checksum.c
@@ -17,16 +17,13 @@
  * Original code by Hannes Gredler ([email protected])
  */
 
-#ifdef HAVE_CONFIG_H
 #include <config.h>
-#endif
 
 #include "netdissect-stdinc.h"
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <assert.h>
 
 #include "netdissect.h"
 
@@ -91,8 +88,7 @@ verify_crc10_cksum(uint16_t accum, const u_char *p, int length)
 {
     int i;
 
-    for ( i = 0;  i < length;  i++ )
-    {
+    for ( i = 0;  i < length;  i++ ) {
         accum = ((accum << 8) & 0x3ff)
             ^ crc10_table[( accum >> 2) & 0xff]
             ^ *p++;
@@ -110,9 +106,9 @@ create_osi_cksum (const uint8_t *pptr, int checksum_offset, int length)
 
     int x;
     int y;
-    uint32_t mul;
+    int32_t mul;
     uint32_t c0;
-    uint32_t c1;
+    uint64_t c1;
     uint16_t checksum;
     int idx;
 
@@ -138,21 +134,23 @@ create_osi_cksum (const uint8_t *pptr, int checksum_offset, int length)
 
     mul = (length - checksum_offset)*(c0);
 
-    x = mul - c0 - c1;
-    y = c1 - mul - 1;
-
-    if ( y >= 0 ) y++;
-    if ( x < 0 ) x--;
+    /*
+     * Casting c0 and c1 here is guaranteed to be safe, because we know
+     * they have values between 0 and 254 inclusive.  These casts are
+     * done to ensure that all of the arithmetic operations are
+     * well-defined (i.e., not mixing signed and unsigned integers).
+     */
+    x = mul - (int)c0 - (int)c1;
+    y = (int)c1 - mul;
 
     x %= 255;
     y %= 255;
 
-
-    if (x == 0) x = 255;
-    if (y == 0) y = 255;
+    if (x <= 0) x += 255;
+    if (y <= 0) y += 255;
 
     y &= 0x00FF;
-    checksum = ((x << 8) | y);
+    checksum = (uint16_t)((x << 8) | y);
 
     return checksum;
 }