diff mbox

ipconfig: add nameserver IPs to kernel-parameter ip=

Message ID 1348176485.3858.92.camel@mars
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Christoph Fritz Sept. 20, 2012, 9:28 p.m. UTC 
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>
---
 Documentation/filesystems/nfs/nfsroot.txt |    7 +++++
 net/ipv4/ipconfig.c                       |   39 ++++++++++++++++++++++++++--
 2 files changed, 43 insertions(+), 3 deletions(-)

Comments

David Miller Sept. 20, 2012, 9:37 p.m. UTC | #1 
From: Christoph Fritz <chf.fritz@googlemail.com>
Date: Thu, 20 Sep 2012 23:28:05 +0200

> +			pr_info("     nameserver%u=%pI4",
> +							i, &ic_nameservers[i]);

Why don't you just tab that second line out to planet Mars while
you're at it?

Please format this correctly, the goal is not to use a million
TAB characters.  Rather, the goal is to get the text starting
on the second line of a function call to line up with the
first column after the openning parenthesis on the previous line.

What you're doing there looks awful, so you'll need to fix this
up before this patch will be considered seriously.

Thanks.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/Documentation/filesystems/nfs/nfsroot.txt b/Documentation/filesystems/nfs/nfsroot.txt
index ffdd9d8..4ed7875 100644
--- a/Documentation/filesystems/nfs/nfsroot.txt
+++ b/Documentation/filesystems/nfs/nfsroot.txt
@@ -158,6 +158,13 @@  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
 
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index 67e8a6b..bfbd61e 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -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;