path: root/net/ipv4/ipconfig.c

/*
 *  Automatic Configuration of IP -- use DHCP, BOOTP, RARP, or
 *  user-supplied information to configure own IP address and routes.
 *
 *  Copyright (C) 1996-1998 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
 *
 *  Derived from network configuration code in fs/nfs/nfsroot.c,
 *  originally Copyright (C) 1995, 1996 Gero Kuhlmann and me.
 *
 *  BOOTP rewritten to construct and analyse packets itself instead
 *  of misusing the IP layer. num_bugs_causing_wrong_arp_replies--;
 *					     -- MJ, December 1998
 *
 *  Fixed ip_auto_config_setup calling at startup in the new "Linker Magic"
 *  initialization scheme.
 *	- Arnaldo Carvalho de Melo <acme@conectiva.com.br>, 08/11/1999
 *
 *  DHCP support added.  To users this looks like a whole separate
 *  protocol, but we know it's just a bag on the side of BOOTP.
 *		-- Chip Salzenberg <chip@valinux.com>, May 2000
 *
 *  Ported DHCP support from 2.2.16 to 2.4.0-test4
 *              -- Eric Biederman <ebiederman@lnxi.com>, 30 Aug 2000
 *
 *  Merged changes from 2.2.19 into 2.4.3
 *              -- Eric Biederman <ebiederman@lnxi.com>, 22 April Aug 2001
 *
 *  Multiple Nameservers in /proc/net/pnp
 *              --  Josef Siemes <jsiemes@web.de>, Aug 2002
 */

#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/utsname.h>
#include <linux/in.h>
#include <linux/if.h>
#include <linux/inet.h>
#include <linux/inetdevice.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/socket.h>
#include <linux/route.h>
#include <linux/udp.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/major.h>
#include <linux/root_dev.h>
#include <linux/delay.h>
#include <linux/nfs_fs.h>
#include <net/net_namespace.h>
#include <net/arp.h>
#include <net/ip.h>
#include <net/ipconfig.h>
#include <net/route.h>

#include <asm/uaccess.h>
#include <net/checksum.h>
#include <asm/processor.h>

/* Define this to allow debugging output */
#undef IPCONFIG_DEBUG

#ifdef IPCONFIG_DEBUG
#define DBG(x) printk x
#else
#define DBG(x) do { } while(0)
#endif

#if defined(CONFIG_IP_PNP_DHCP)
#define IPCONFIG_DHCP
#endif
#if defined(CONFIG_IP_PNP_BOOTP) || defined(CONFIG_IP_PNP_DHCP)
#define IPCONFIG_BOOTP
#endif
#if defined(CONFIG_IP_PNP_RARP)
#define IPCONFIG_RARP
#endif
#if defined(IPCONFIG_BOOTP) || defined(IPCONFIG_RARP)
#define IPCONFIG_DYNAMIC
#endif

/* Define the friendly delay before and after opening net devices */
#define CONF_PRE_OPEN		500	/* Before opening: 1/2 second */
#define CONF_POST_OPEN		1	/* After opening: 1 second */

/* Define the timeout for waiting for a DHCP/BOOTP/RARP reply */
#define CONF_OPEN_RETRIES 	2	/* (Re)open devices twice */
#define CONF_SEND_RETRIES 	6	/* Send six requests per open */
#define CONF_INTER_TIMEOUT	(HZ/2)	/* Inter-device timeout: 1/2 second */
#define CONF_BASE_TIMEOUT	(HZ*2)	/* Initial timeout: 2 seconds */
#define CONF_TIMEOUT_RANDOM	(HZ)	/* Maximum amount of randomization */
#define CONF_TIMEOUT_MULT	*7/4	/* Rate of timeout growth */
#define CONF_TIMEOUT_MAX	(HZ*30)	/* Maximum allowed timeout */
#define CONF_NAMESERVERS_MAX   3       /* Maximum number of nameservers
					   - '3' from resolv.h */

#define NONE __constant_htonl(INADDR_NONE)
#define ANY __constant_htonl(INADDR_ANY)

/*
 * Public IP configuration
 */

/* This is used by platforms which might be able to set the ipconfig
 * variables using firmware environment vars.  If this is set, it will
 * ignore such firmware variables.
 */
int ic_set_manually __initdata = 0;		/* IPconfig parameters set manually */

static int ic_enable __initdata = 0;		/* IP config enabled? */

/* Protocol choice */
int ic_proto_enabled __initdata = 0
#ifdef IPCONFIG_BOOTP
			| IC_BOOTP
#endif
#ifdef CONFIG_IP_PNP_DHCP
			| IC_USE_DHCP
#endif
#ifdef IPCONFIG_RARP
			| IC_RARP
#endif
			;

static int ic_host_name_set __initdata = 0;	/* Host name set by us? */

__be32 ic_myaddr = NONE;		/* My IP address */
static __be32 ic_netmask = NONE;	/* Netmask for local subnet */
__be32 ic_gateway = NONE;	/* Gateway IP address */

__be32 ic_servaddr = NONE;	/* Boot server IP address */

__be32 root_server_addr = NONE;	/* Address of NFS server */
u8 root_server_path[256] = { 0, };	/* Path to mount as root */

/* vendor class identifier */
static char vendor_class_identifier[253] __initdata;

/* Persistent data: */

static int ic_proto_used;			/* Protocol used, if any */
static __be32 ic_nameservers[CONF_NAMESERVERS_MAX]; /* DNS Server IP addresses */
static u8 ic_domain[64];		/* DNS (not NIS) domain name */

/*
 * Private state.
 */

/* Name of user-selected boot device */
static char user_dev_name[IFNAMSIZ] __initdata = { 0, };

/* Protocols supported by available interfaces */
static int ic_proto_have_if __initdata = 0;

#ifdef IPCONFIG_DYNAMIC
static DEFINE_SPINLOCK(ic_recv_lock);
static volatile int ic_got_reply __initdata = 0;    /* Proto(s) that replied */
#endif
#ifdef IPCONFIG_DHCP
static int ic_dhcp_msgtype __initdata = 0;	/* DHCP msg type received */
#endif


/*
 *	Network devices
 */

struct ic_device {
	struct ic_device *next;
	struct net_device *dev;
	unsigned short flags;
	short able;
	__be32 xid;
};

static struct ic_device *ic_first_dev __initdata = NULL;/* List of open device */
static struct net_device *ic_dev __initdata = NULL;	/* Selected device */

static int __init ic_open_devs(void)
{
	struct ic_device *d, **last;
	struct net_device *dev;
	unsigned short oflags;

	last = &ic_first_dev;
	rtnl_lock();

	/* bring loopback device up first */
	for_each_netdev(&init_net, dev) {
		if (!(dev->flags & IFF_LOOPBACK))
			continue;
		if (dev_change_flags(dev, dev->flags | IFF_UP) < 0)
			printk(KERN_ERR "IP-Config: Failed to open %s\n", dev->name);
	}

	for_each_netdev(&init_net, dev) {
		if (dev->flags & IFF_LOOPBACK)
			continue;
		if (user_dev_name[0] ? !strcmp(dev->name, user_dev_name) :
		    (!(dev->flags & IFF_LOOPBACK) &&
		     (dev->flags & (IFF_POINTOPOINT|IFF_BROADCAST)) &&
		     strncmp(dev->name, "dummy", 5))) {
			int able = 0;
			if (dev->mtu >= 364)
				able |= IC_BOOTP;
			else
				printk(KERN_WARNING "DHCP/BOOTP: Ignoring device %s, MTU %d too small", dev->name, dev->mtu);
			if (!(dev->flags & IFF_NOARP))
				able |= IC_RARP;
			able &= ic_proto_enabled;
			if (ic_proto_enabled && !able)
				continue;
			oflags = dev->flags;
			if (dev_change_flags(dev, oflags | IFF_UP) < 0) {
				printk(KERN_ERR "IP-Config: Failed to open %s\n", dev->name);
				continue;
			}
			if (!(d = kmalloc(sizeof(struct ic_device), GFP_KERNEL))) {
				rtnl_unlock();
				return -1;
			}
			d->dev = dev;
			*last = d;
			last = &d->next;
			d->flags = oflags;
			d->able = able;
			if (able & IC_BOOTP)
				get_random_bytes(&d->xid, sizeof(__be32));
			else
				d->xid = 0;
			ic_proto_have_if |= able;
			DBG(("IP-Config: %s UP (able=%d, xid=%08x)\n",
				dev->name, able, d->xid));
		}
	}
	rtnl_unlock();

	*last = NULL;

	if (!ic_first_dev) {
		if (user_dev_name[0])
			printk(KERN_ERR "IP-Config: Device `%s' not found.\n", user_dev_name);
		else