[IPCONFIG]: The kernel gets no IP from some DHCP servers

From: Stephen Hemminger <shemminger@linux-foundation.org>

Based upon a patch by Marcel Wappler:

   This patch fixes a DHCP issue of the kernel: some DHCP servers
   (i.e.  in the Linksys WRT54Gv5) are very strict about the contents
   of the DHCPDISCOVER packet they receive from clients.

   Table 5 in RFC2131 page 36 requests the fields 'ciaddr' and
   'siaddr' MUST be set to '0'.  These DHCP servers ignore Linux
   kernel's DHCP discovery packets with these two fields set to
   '255.255.255.255' (in contrast to popular DHCP clients, such as
   'dhclient' or 'udhcpc').  This leads to a not booting system.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index 10013cc..5dd9385 100644 (file)
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -753,9 +753,9 @@ static void __init ic_bootp_send_if(struct ic_device *d, unsigned long jiffies_d
                printk("Unknown ARP type 0x%04x for device %s\n", dev->type, dev->name);
                b->htype = dev->type; /* can cause undefined behavior */
        }
+
+       /* server_ip and your_ip address are both already zero per RFC2131 */
        b->hlen = dev->addr_len;
-       b->your_ip = NONE;
-       b->server_ip = NONE;
        memcpy(b->hw_addr, dev->dev_addr, dev->addr_len);
        b->secs = htons(jiffies_diff / HZ);
        b->xid = d->xid;