From: Mathieu Trudel-Lapierre <mathieu.trudel-lapierre@canonical.com>
Date: Sun, 6 Jan 2019 19:33:01 +0000 (+0000)
Subject: Set broadcast when sending DHCPREQUEST and DHCPDISCOVER
X-Git-Tag: archive/raspbian/2.0.4-15+rpi1^2~18
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=370d7c4bd1965c113c7423b2009cd008097a0451;p=klibc.git

Set broadcast when sending DHCPREQUEST and DHCPDISCOVER

We need to do this, since our devices are probably not configured yet and
there may be more than one device we're trying to do DHCP on on the same
network. Otherwise, things might be dropped.

Patch is originally from here:
https://bugs.launchpad.net/ubuntu/+source/klibc/+bug/1327412/comments/5
... but the reporter "patpat" has not provided contact information, and
this is independently verifiable by looking at RFC 2131, section 4.1,
page 24.


Gbp-Pq: Name broadcast_dhcp_send.patch
---

diff --git a/usr/kinit/ipconfig/dhcp_proto.c b/usr/kinit/ipconfig/dhcp_proto.c
index ebf79cc..d5b759b 100644
--- a/usr/kinit/ipconfig/dhcp_proto.c
+++ b/usr/kinit/ipconfig/dhcp_proto.c
@@ -201,8 +201,14 @@ static int dhcp_send(struct netdev *dev, struct iovec *vec)
 	bootp.hlen	= dev->hwlen;
 	bootp.xid	= dev->bootp.xid;
 	bootp.ciaddr	= INADDR_ANY;
-	bootp.yiaddr	= dev->ip_addr;
+	/* yiaddr should always be set to 0 for the messages we're likely
+	 * to send as a DHCP client: DHCPDISCOVER, DHCPREQUEST, DHCPDECLINE,
+	 * DHCPINFORM, DHCPRELEASE
+	 * cf. RFC2131 section 4.1.1, table 5.
+	 */
+	bootp.yiaddr	= INADDR_ANY;
 	bootp.giaddr	= INADDR_ANY;
+	bootp.flags	= htons(0x8000);
 	bootp.secs	= htons(time(NULL) - dev->open_time);
 	memcpy(bootp.chaddr, dev->hwaddr, 16);