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ipconfig: add nameserver IPs to kernel-parameter ip= 

On small systems (e.g. embedded ones) IP addresses are often configured
by bootloaders and get assigned to kernel via parameter "ip=".  If set to
"ip=dhcp", even nameserver entries from DHCP daemons are handled. These
entries exported in /proc/net/pnp are commonly linked by /etc/resolv.conf.

To configure nameservers for networks without DHCP, this patch adds option
<dns0-ip> and <dns1-ip> to kernel-parameter 'ip='.

Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
Tested-by: Jan Weitzel <j.weitzel@phytec.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Christoph Fritz 2012-09-21 08:31:19 +00:00 committed by David S. Miller
parent 42d94dcb68
commit 5e953778a2
2 changed files with 45 additions and 4 deletions
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10
Documentation/filesystems/nfs/nfsroot.txt
View File

@ -78,7 +78,8 @@ nfsroot=[<server-ip>:]<root-dir>[,<nfs-options>]
flags = hard, nointr, noposix, cto, ac
ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>:
<dns0-ip>:<dns1-ip>
This parameter tells the kernel how to configure IP addresses of devices
and also how to set up the IP routing table. It was originally called
@ -158,6 +159,13 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
Default: any
<dns0-ip> IP address of first nameserver.
Value gets exported by /proc/net/pnp which is often linked
on embedded systems by /etc/resolv.conf.
<dns1-ip> IP address of secound nameserver.
Same as above.
nfsrootdebug

39
net/ipv4/ipconfig.c
View File

@ -743,14 +743,22 @@ static void __init ic_bootp_init_ext(u8 *e)
/*
* Initialize the DHCP/BOOTP mechanism.
* Predefine Nameservers
*/
static inline void __init ic_bootp_init(void)
static inline void __init ic_nameservers_predef(void)
{
int i;
for (i = 0; i < CONF_NAMESERVERS_MAX; i++)
ic_nameservers[i] = NONE;
}
/*
* Initialize the DHCP/BOOTP mechanism.
*/
static inline void __init ic_bootp_init(void)
{
ic_nameservers_predef();
dev_add_pack(&bootp_packet_type);
}
@ -1379,6 +1387,7 @@ static int __init ip_auto_config(void)
int retries = CONF_OPEN_RETRIES;
#endif
int err;
unsigned int i;
#ifdef CONFIG_PROC_FS
proc_net_fops_create(&init_net, "pnp", S_IRUGO, &pnp_seq_fops);
@ -1499,7 +1508,15 @@ static int __init ip_auto_config(void)
&ic_servaddr, &root_server_addr, root_server_path);
if (ic_dev_mtu)
pr_cont(", mtu=%d", ic_dev_mtu);
pr_cont("\n");
for (i = 0; i < CONF_NAMESERVERS_MAX; i++)
if (ic_nameservers[i] != NONE) {
pr_info(" nameserver%u=%pI4",
i, &ic_nameservers[i]);
break;
}
for (i++; i < CONF_NAMESERVERS_MAX; i++)
if (ic_nameservers[i] != NONE)
pr_cont(", nameserver%u=%pI4\n", i, &ic_nameservers[i]);
#endif /* !SILENT */
return 0;
@ -1570,6 +1587,8 @@ static int __init ip_auto_config_setup(char *addrs)
return 1;
}
ic_nameservers_predef();
/* Parse string for static IP assignment. */
ip = addrs;
while (ip && *ip) {
@ -1613,6 +1632,20 @@ static int __init ip_auto_config_setup(char *addrs)
ic_enable = 0;
}
break;
case 7:
if (CONF_NAMESERVERS_MAX >= 1) {
ic_nameservers[0] = in_aton(ip);
if (ic_nameservers[0] == ANY)
ic_nameservers[0] = NONE;
}
break;
case 8:
if (CONF_NAMESERVERS_MAX >= 2) {
ic_nameservers[1] = in_aton(ip);
if (ic_nameservers[1] == ANY)
ic_nameservers[1] = NONE;
}
break;
}
}
ip = cp;