Merge branch 'ipconfig-NTP-server-support-bug-fixes-documentation-improvements'

Updated 1997 by Martin Mares <mj@atrey.karlin.mff.cuni.cz>

Updated 2006 by Nico Schottelius <nico-kernel-nfsroot@schottelius.org>

Updated 2006 by Horms <horms@verge.net.au>

Updated 2018 by Chris Novakovic <chris@chrisn.me.uk>

ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>:

   <dns0-ip>:<dns1-ip>

   <dns0-ip>:<dns1-ip>:<ntp0-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

		will not be triggered if it is missing and NFS root is not

		in operation.

		Value is exported to /proc/net/pnp with the prefix "bootserver "

		(see below).

		Default: Determined using autoconfiguration.

		         The address of the autoconfiguration server is used.

		Default:  Determined using autoconfiguration.

  <hostname>	Name of the client. May be supplied by autoconfiguration,

  		but its absence will not trigger autoconfiguration.

		If specified and DHCP is used, the user provided hostname will

		be carried in the DHCP request to hopefully update DNS record.

  <hostname>	Name of the client. If a '.' character is present, anything

		before the first '.' is used as the client's hostname, and anything

		after it is used as its NIS domain name. May be supplied by

		autoconfiguration, but its absence will not trigger autoconfiguration.

		If specified and DHCP is used, the user-provided hostname (and NIS

		domain name, if present) will be carried in the DHCP request; this

		may cause a DNS record to be created or updated for the client.

  		Default: Client IP address is used in ASCII notation.

                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.

  <dns0-ip>	IP address of primary nameserver.

		Value is exported to /proc/net/pnp with the prefix "nameserver "

		(see below).

		Default: None if not using autoconfiguration; determined

		automatically if using autoconfiguration.

  <dns1-ip>	IP address of secondary nameserver.

		See <dns0-ip>.

  <ntp0-ip>	IP address of a Network Time Protocol (NTP) server.

		Value is exported to /proc/net/ipconfig/ntp_servers, but is

		otherwise unused (see below).

		Default: None if not using autoconfiguration; determined

		automatically if using autoconfiguration.

  After configuration (whether manual or automatic) is complete, two files

  are created in the following format; lines are omitted if their respective

  value is empty following configuration:

  - /proc/net/pnp:

	#PROTO: <DHCP|BOOTP|RARP|MANUAL>	(depending on configuration method)

	domain <dns-domain>			(if autoconfigured, the DNS domain)

	nameserver <dns0-ip>			(primary name server IP)

	nameserver <dns1-ip>			(secondary name server IP)

	nameserver <dns2-ip>			(tertiary name server IP)

	bootserver <server-ip>			(NFS server IP)

  - /proc/net/ipconfig/ntp_servers:

	<ntp0-ip>				(NTP server IP)

	<ntp1-ip>				(NTP server IP)

	<ntp2-ip>				(NTP server IP)

  <dns-domain> and <dns2-ip> (in /proc/net/pnp) and <ntp1-ip> and <ntp2-ip>

  (in /proc/net/ipconfig/ntp_servers) are requested during autoconfiguration;

  they cannot be specified as part of the "ip=" kernel command line parameter.

  Because the "domain" and "nameserver" options are recognised by DNS

  resolvers, /etc/resolv.conf is often linked to /proc/net/pnp on systems

  that use an NFS root filesystem.

  <dns1-ip>	IP address of second nameserver.

		Same as above.

  Note that the kernel will not synchronise the system time with any NTP

  servers it discovers; this is the responsibility of a user space process

  (e.g. an initrd/initramfs script that passes the IP addresses listed in

  /proc/net/ipconfig/ntp_servers to an NTP client before mounting the real

  root filesystem if it is on NFS).

nfsrootdebug

 *

 *  Multiple Nameservers in /proc/net/pnp

 *              --  Josef Siemes <jsiemes@web.de>, Aug 2002

 *

 *  NTP servers in /proc/net/ipconfig/ntp_servers

 *              --  Chris Novakovic <chris@chrisn.me.uk>, April 2018

 */

#include <linux/types.h>

#define CONF_TIMEOUT_MAX	(HZ*30)	/* Maximum allowed timeout */

#define CONF_NAMESERVERS_MAX   3       /* Maximum number of nameservers

					   - '3' from resolv.h */

#define CONF_NTP_SERVERS_MAX   3	/* Maximum number of NTP servers */

#define NONE cpu_to_be32(INADDR_NONE)

#define ANY cpu_to_be32(INADDR_ANY)

#define ic_proto_used 0

#endif

static __be32 ic_nameservers[CONF_NAMESERVERS_MAX]; /* DNS Server IP addresses */

static __be32 ic_ntp_servers[CONF_NTP_SERVERS_MAX]; /* NTP server IP addresses */

static u8 ic_domain[64];		/* DNS (not NIS) domain name */

/*

 * Private state.

 */

/* proc_dir_entry for /proc/net/ipconfig */

static struct proc_dir_entry *ipconfig_dir;

/* Name of user-selected boot device */

static char user_dev_name[IFNAMSIZ] __initdata = { 0, };

		ic_nameservers[i] = NONE;

}

/* Predefine NTP servers */

static inline void __init ic_ntp_servers_predef(void)

{

	int i;

	for (i = 0; i < CONF_NTP_SERVERS_MAX; i++)

		ic_ntp_servers[i] = NONE;

}

/*

 *	DHCP/BOOTP support.

 */

			17,	/* Boot path */

			26,	/* MTU */

			40,	/* NIS domain name */

			42,	/* NTP servers */

		};

		*e++ = 55;	/* Parameter request list */

	*e++ = 3;		/* Default gateway request */

	*e++ = 4;

	e += 4;

	*e++ = 5;		/* Name server request */

	*e++ = 8;

	e += 8;

#if CONF_NAMESERVERS_MAX > 0

	*e++ = 6;		/* (DNS) name server request */

	*e++ = 4 * CONF_NAMESERVERS_MAX;

	e += 4 * CONF_NAMESERVERS_MAX;

#endif

	*e++ = 12;		/* Host name request */

	*e++ = 32;

	e += 32;

 */

static inline void __init ic_bootp_init(void)

{

	/* Re-initialise all name servers and NTP servers to NONE, in case any

	 * were set via the "ip=" or "nfsaddrs=" kernel command line parameters:

	 * any IP addresses specified there will already have been decoded but

	 * are no longer needed

	 */

	ic_nameservers_predef();

	ic_ntp_servers_predef();

	dev_add_pack(&bootp_packet_type);

}

		ic_bootp_string(utsname()->domainname, ext+1, *ext,

				__NEW_UTS_LEN);

		break;

	case 42:	/* NTP servers */

		servers = *ext / 4;

		if (servers > CONF_NTP_SERVERS_MAX)

			servers = CONF_NTP_SERVERS_MAX;

		for (i = 0; i < servers; i++) {

			if (ic_ntp_servers[i] == NONE)

				memcpy(&ic_ntp_servers[i], ext+1+4*i, 4);

		}

		break;

	}

}

#ifdef CONFIG_PROC_FS

/* Name servers: */

static int pnp_seq_show(struct seq_file *seq, void *v)

{

	int i;

	.llseek		= seq_lseek,

	.release	= single_release,

};

/* Create the /proc/net/ipconfig directory */

static int __init ipconfig_proc_net_init(void)

{

	ipconfig_dir = proc_net_mkdir(&init_net, "ipconfig", init_net.proc_net);

	if (!ipconfig_dir)

		return -ENOMEM;

	return 0;

}

/* Create a new file under /proc/net/ipconfig */

static int ipconfig_proc_net_create(const char *name,

				    const struct file_operations *fops)

{

	char *pname;

	struct proc_dir_entry *p;

	if (!ipconfig_dir)

		return -ENOMEM;

	pname = kasprintf(GFP_KERNEL, "%s%s", "ipconfig/", name);

	if (!pname)

		return -ENOMEM;

	p = proc_create(pname, 0444, init_net.proc_net, fops);

	kfree(pname);

	if (!p)

		return -ENOMEM;

	return 0;

}

/* Write NTP server IP addresses to /proc/net/ipconfig/ntp_servers */

static int ntp_servers_seq_show(struct seq_file *seq, void *v)

{

	int i;

	for (i = 0; i < CONF_NTP_SERVERS_MAX; i++) {

		if (ic_ntp_servers[i] != NONE)

			seq_printf(seq, "%pI4\n", &ic_ntp_servers[i]);

	}

	return 0;

}

static int ntp_servers_seq_open(struct inode *inode, struct file *file)

{

	return single_open(file, ntp_servers_seq_show, NULL);

}

static const struct file_operations ntp_servers_seq_fops = {

	.open		= ntp_servers_seq_open,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= single_release,

};

#endif /* CONFIG_PROC_FS */

/*

	int err;

	unsigned int i;

	/* Initialise all name servers and NTP servers to NONE (but only if the

	 * "ip=" or "nfsaddrs=" kernel command line parameters weren't decoded,

	 * otherwise we'll overwrite the IP addresses specified there)

	 */

	if (ic_set_manually == 0) {

		ic_nameservers_predef();

		ic_ntp_servers_predef();

	}

#ifdef CONFIG_PROC_FS

	proc_create("pnp", 0444, init_net.proc_net, &pnp_seq_fops);

	if (ipconfig_proc_net_init() == 0)

		ipconfig_proc_net_create("ntp_servers", &ntp_servers_seq_fops);

#endif /* CONFIG_PROC_FS */

	if (!ic_enable)

		&ic_servaddr, &root_server_addr, root_server_path);

	if (ic_dev_mtu)

		pr_cont(", mtu=%d", ic_dev_mtu);

	for (i = 0; i < CONF_NAMESERVERS_MAX; i++)

	/* Name servers (if any): */

	for (i = 0; i < CONF_NAMESERVERS_MAX; i++) {

		if (ic_nameservers[i] != NONE) {

			pr_cont("     nameserver%u=%pI4",

			if (i == 0)

				pr_info("     nameserver%u=%pI4",

					i, &ic_nameservers[i]);

			else

				pr_cont(", 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", i, &ic_nameservers[i]);

		if (i + 1 == CONF_NAMESERVERS_MAX)

			pr_cont("\n");

	}

	/* NTP servers (if any): */

	for (i = 0; i < CONF_NTP_SERVERS_MAX; i++) {

		if (ic_ntp_servers[i] != NONE) {

			if (i == 0)

				pr_info("     ntpserver%u=%pI4",

					i, &ic_ntp_servers[i]);

			else

				pr_cont(", ntpserver%u=%pI4",

					i, &ic_ntp_servers[i]);

		}

		if (i + 1 == CONF_NTP_SERVERS_MAX)

			pr_cont("\n");

	}

#endif /* !SILENT */

	/*

		return 1;

	}

	/* Initialise all name servers and NTP servers to NONE */

	ic_nameservers_predef();

	ic_ntp_servers_predef();

	/* Parse string for static IP assignment.  */

	ip = addrs;

						ic_nameservers[1] = NONE;

				}

				break;

			case 9:

				if (CONF_NTP_SERVERS_MAX >= 1) {

					ic_ntp_servers[0] = in_aton(ip);

					if (ic_ntp_servers[0] == ANY)

						ic_ntp_servers[0] = NONE;

				}

				break;

			}

		}

		ip = cp;