inet_cksum(): use unsigned types and change return type

Fix Coverity Scan CID 469910 (Overflowed constant) Signed-off-by: Joachim Wiberg <[email protected]>
troglobit · Oct 28, 2024 · d3d9d32 · d3d9d32
1 parent b47e381
commit d3d9d32
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Showing 2 changed files with 4 additions and 6 deletions.
diff --git a/src/defs.h b/src/defs.h
@@ -358,7 +358,7 @@ extern char            *inet_name(uint32_t, int);
 extern char            *inet_fmt(uint32_t, char *, size_t);
 extern char            *inet_fmts(uint32_t, uint32_t, char *, size_t);
 extern uint32_t		inet_parse(char *, int);
-extern int		inet_cksum(uint16_t *, uint32_t);
+extern uint16_t		inet_cksum(uint16_t *, uint32_t);
 
 /* prune.c */
 extern struct gtable	*kernel_table;

diff --git a/src/inet.c b/src/inet.c
@@ -225,12 +225,12 @@ uint32_t inet_parse(char *s, int n)
  * Checksum routine for Internet Protocol family headers (C Version)
  *
  */
-int inet_cksum(uint16_t *addr, uint32_t len)
+uint16_t inet_cksum(uint16_t *addr, uint32_t len)
 {
     int nleft = (int)len;
     uint16_t *w = addr;
     uint16_t answer = 0;
-    int32_t sum = 0;
+    uint32_t sum = 0;
 
     /*
      *  Our algorithm is simple, using a 32 bit accumulator (sum),
@@ -254,9 +254,7 @@ int inet_cksum(uint16_t *addr, uint32_t len)
      */
     sum = (sum >> 16) + (sum & 0xffff);	/* add hi 16 to low 16 */
     sum += (sum >> 16);			/* add carry */
-    answer = ~sum;			/* truncate to 16 bits */
-
-    return answer;
+    return (uint16_t)~sum;		/* truncate to 16 bits */
 }
 
 /**