[PATCH] Add 32bit emulation for cmsg SO_TIMESTAMP

[Andi Kleen <ak@xxxxxxx>]

Some traceroute versions use the SO_TIMESTAMP cmsg for time measurement.
This fixes them when running as 32bit on a 64bit x86-64 kernel.

-Andi

--- linux-2.6.1rc2-amd64/net/compat.c-o 2003-11-23 19:46:36.000000000 -0800
+++ linux-2.6.1rc2-amd64/net/compat.c   2004-01-07 00:21:43.741256711 -0800
@@ -215,15 +215,25 @@
 
 int put_cmsg_compat(struct msghdr *kmsg, int level, int type, int len, void 
*data)
 {
+       struct compat_timeval ctv;
        struct compat_cmsghdr *cm = (struct compat_cmsghdr *) kmsg->msg_control;
        struct compat_cmsghdr cmhdr;
-       int cmlen = CMSG_COMPAT_LEN(len);
+       int cmlen;
 
        if(cm == NULL || kmsg->msg_controllen < sizeof(*cm)) {
                kmsg->msg_flags |= MSG_CTRUNC;
                return 0; /* XXX: return error? check spec. */
        }
 
+       if (level == SOL_SOCKET && type == SO_TIMESTAMP) { 
+               struct timeval *tv = (struct timeval *)data;
+               ctv.tv_sec = tv->tv_sec;
+               ctv.tv_usec = tv->tv_usec;
+               data = &ctv;
+               len = sizeof(struct compat_timeval);
+       } 
+       
+       cmlen = CMSG_COMPAT_LEN(len);
        if(kmsg->msg_controllen < cmlen) {
                kmsg->msg_flags |= MSG_CTRUNC;
                cmlen = kmsg->msg_controllen;