Date: Tue, 18 Sep 2012 13:28:50 GMT From: Stephen Workman <workman.stephen@gmail.com> To: freebsd-gnats-submit@FreeBSD.org Subject: misc/171744: [PATCH] Fix wake command not sending proper WOL packet Message-ID: <201209181328.q8IDSow0048866@red.freebsd.org> Resent-Message-ID: <201209181330.q8IDUAkf026839@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
>Number: 171744
>Category: misc
>Synopsis: [PATCH] Fix wake command not sending proper WOL packet
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Sep 18 13:30:10 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator: Stephen Workman
>Release: FreeBSD 9.0-RELEASE-p3
>Organization:
>Environment:
FreeBSD DarkTower 9.0-RELEASE-p3 FreeBSD 9.0-RELEASE-p3 #0: Tue Jun 12 02:52:29 UTC 2012 root@amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC amd64
>Description:
The current version of the wake command (/usr/sbin/wake) sends an improperly formatted WOL packet. It is "improper" due to the fact that it sends to the broadcast address of ff:ff:ff:ff:ff:ff instead of the address(es) specified on the command line. Because of this, the packet never makes it to the target host and thus, does not wake up the "sleeping" target.
I believe, in my case, the packet isn't even leaving the FreeBSD host.
>How-To-Repeat:
Run tcpdump on the target host: (tcpdump -i <IF> -nne not tcp and not udp and not icmp) - or use Wireshark on a Windows host.
Use "wake" to send a WOL packet to the target's MAC address (e.g.: wake xl0 00:11:22:33:44:55)
The packet will not be received on the target.
>Fix:
Send the packet to the target MAC address instead of the broadcast MAC. The patch I have attached makes this change. I have tested it, and it works as expected.
Additionally, I have modified the ether_type value to use 0x0842 as this is recognized by tools such as Wireshark and is also used by some other WOL utilities. Also, emits a message to the screen when it sends a packet.
Patch attached with submission follows:
--- /usr/src/usr.sbin/wake/wake.c 2012-01-02 22:25:54.000000000 -0500
+++ wake.c 2012-09-18 08:23:32.000000000 -0400
@@ -160,8 +160,18 @@
ssize_t len;
int i;
- (void)memset(pkt.hdr.ether_dhost, 0xff, sizeof(pkt.hdr.ether_dhost));
- pkt.hdr.ether_type = htons(0);
+ /* Be useful */
+ printf("Sending magic packet to ");
+ for(i = 0; i < ETHER_ADDR_LEN - 1; i++)
+ printf("%.2X:", addr->octet[i]);
+ printf("%.2X\n", addr->octet[ETHER_ADDR_LEN-1]);
+
+ /* The packet MUST be sent to the target MAC address */
+ memcpy(pkt.hdr.ether_dhost, addr, ETHER_ADDR_LEN);
+
+ /* EtherType 0x0842 is at least semi-recognizable for WOL */
+ pkt.hdr.ether_type = htons(0x0842);
+
(void)memset(pkt.data, 0xff, SYNC_LEN);
for (p = pkt.data + SYNC_LEN, i = 0; i < DESTADDR_COUNT;
p += ETHER_ADDR_LEN, i++)
>Release-Note:
>Audit-Trail:
>Unformatted:
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201209181328.q8IDSow0048866>