Bug#521857: 64bit casting v2

[Yiannis Marangos]

ettercap-0.7.3-amd64-casting.diff patch has problem because of this:

-   opt_end = (u_char *)((int)tcp + tcp->off * 4);
+   opt_end = (u_char *)(tcp + tcp->off * 4);

the variable tcp is struct tcp_header* and the sizeof(struct tcp_header)
is 20 bytes..
for example if the tcp is 0x0 and the tcp->off is 5 the result will be
0x0 + sizeof(struct tcp_header) * 5 * 4
which is 0x190 instead of 0x20
a way to correct this problem is to change the datatype int to datatype
long which is always the size of registers so the casting will be correct..

i attach a second version of the 64bit-casting patch..

--- ettercap-0.7.3.orig/src/protocols/ec_tcp.c
+++ ettercap-0.7.3/src/protocols/ec_tcp.c
@@ -116,7 +116,7 @@
    tcp = (struct tcp_header *)DECODE_DATA;
    
    opt_start = (u_char *)(tcp + 1);
-   opt_end = (u_char *)((int)tcp + tcp->off * 4);
+   opt_end = (u_char *)((long)tcp + tcp->off * 4);
 
    DECODED_LEN = (u_int32)(tcp->off * 4);