C compilers can, and some do, optimize away pointer underflow checks.

[tcpdump] / print-dccp.c

diff --git a/print-dccp.c b/print-dccp.c
index 634c27e9fcaa7892c761721695ee37f71468cf53..fee4a6e50574f8d71eb69fe9eeff552a27cb4022 100644 (file)
--- a/print-dccp.c
+++ b/print-dccp.c
@@ -9,7 +9,7 @@
 
 #ifndef lint
 static const char rcsid[] _U_ =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-dccp.c,v 1.7 2006-11-02 09:05:23 hannes Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-dccp.c,v 1.8 2007-11-09 00:44:09 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -277,32 +277,21 @@ void dccp_print(const u_char *bp, const u_char *data2, u_int len)
        }
 
        /* checksum calculation */
-#ifdef INET6
-       if (ip6) {
-               if (ip6->ip6_plen && vflag) {
-                       u_int16_t sum, dccp_sum;
+       if (vflag && TTEST2(bp[0], len)) {
+               u_int16_t sum = 0, dccp_sum;
 
+               dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
+               (void)printf("cksum 0x%04x ", dccp_sum);
+               if (IP_V(ip) == 4)
+                       sum = dccp_cksum(ip, dh, len);
+#ifdef INET6
+               else if (IP_V(ip) == 6)
                        sum = dccp6_cksum(ip6, dh, len);
-                       dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);         
-                       printf("cksum 0x%04x", dccp_sum);               
-                       if (sum != 0) {
-                               (void)printf(" (incorrect -> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
-                       } else
-                               (void)printf(" (correct), ");
-               }                                       
-       } else 
-#endif /* INET6 */
-       if (vflag)
-       {
-               u_int16_t sum, dccp_sum;
-
-               sum = dccp_cksum(ip, dh, len);
-               dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);         
-               printf("cksum 0x%04x", dccp_sum);               
-               if (sum != 0) {
-                       (void)printf(" (incorrect (-> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
-               } else
-                       (void)printf(" (correct), ");
+#endif
+               if (sum != 0)
+                       (void)printf("(incorrect -> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
+               else
+                       (void)printf("(correct), ");
        }
 
        switch (DCCPH_TYPE(dh)) {
@@ -405,9 +394,6 @@ trunc2:
 static int dccp_print_option(const u_char *option)
 {      
        u_int8_t optlen, i;
-       u_int32_t *ts;
-       u_int16_t *var16;
-       u_int32_t *var32;
 
        TCHECK(*option);
 
@@ -481,22 +467,17 @@ static int dccp_print_option(const u_char *option)
                for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));      
                break;
        case 41:
-               ts = (u_int32_t *)(option + 2);
-               printf("timestamp %u", (u_int32_t)ntohl(*ts));
+               printf("timestamp %u", EXTRACT_32BITS(option + 2));
                break;
        case 42:
-               ts = (u_int32_t *)(option + 2);
-               printf("timestamp_echo %u", (u_int32_t)ntohl(*ts));
+               printf("timestamp_echo %u", EXTRACT_32BITS(option + 2));
                break;
        case 43:
                printf("elapsed_time ");
-               if (optlen == 6){
-                       ts = (u_int32_t *)(option + 2);
-                       printf("%u", (u_int32_t)ntohl(*ts));
-               } else {
-                       var16 = (u_int16_t *)(option + 2);
-                       printf("%u", ntohs(*var16));
-               }       
+               if (optlen == 6)
+                       printf("%u", EXTRACT_32BITS(option + 2));
+               else
+                       printf("%u", EXTRACT_16BITS(option + 2));
                break;
        case 44:
                printf("data_checksum ");
@@ -507,12 +488,10 @@ static int dccp_print_option(const u_char *option)
                        printf("CCID option %d",*option);
                        switch (optlen) {
                                case 4:
-                                       var16 = (u_int16_t *)(option + 2);
-                                       printf(" %u",ntohs(*var16));
+                                       printf(" %u", EXTRACT_16BITS(option + 2));
                                        break;
                                case 6:
-                                       var32 = (u_int32_t *)(option + 2);
-                                       printf(" %u",(u_int32_t)ntohl(*var32));
+                                       printf(" %u", EXTRACT_32BITS(option + 2));
                                        break;
                                default:
                                        break;