1 // SPDX-License-Identifier: GPL-2.0
3 * Automatic Configuration of IP -- use DHCP, BOOTP, RARP, or
4 * user-supplied information to configure own IP address and routes.
6 * Copyright (C) 1996-1998 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
8 * Derived from network configuration code in fs/nfs/nfsroot.c,
9 * originally Copyright (C) 1995, 1996 Gero Kuhlmann and me.
11 * BOOTP rewritten to construct and analyse packets itself instead
12 * of misusing the IP layer. num_bugs_causing_wrong_arp_replies--;
13 * -- MJ, December 1998
15 * Fixed ip_auto_config_setup calling at startup in the new "Linker Magic"
16 * initialization scheme.
17 * - Arnaldo Carvalho de Melo <acme@conectiva.com.br>, 08/11/1999
19 * DHCP support added. To users this looks like a whole separate
20 * protocol, but we know it's just a bag on the side of BOOTP.
21 * -- Chip Salzenberg <chip@valinux.com>, May 2000
23 * Ported DHCP support from 2.2.16 to 2.4.0-test4
24 * -- Eric Biederman <ebiederman@lnxi.com>, 30 Aug 2000
26 * Merged changes from 2.2.19 into 2.4.3
27 * -- Eric Biederman <ebiederman@lnxi.com>, 22 April Aug 2001
29 * Multiple Nameservers in /proc/net/pnp
30 * -- Josef Siemes <jsiemes@web.de>, Aug 2002
32 * NTP servers in /proc/net/ipconfig/ntp_servers
33 * -- Chris Novakovic <chris@chrisn.me.uk>, April 2018
36 #include <linux/types.h>
37 #include <linux/string.h>
38 #include <linux/kernel.h>
39 #include <linux/jiffies.h>
40 #include <linux/random.h>
41 #include <linux/init.h>
42 #include <linux/utsname.h>
45 #include <linux/inet.h>
46 #include <linux/inetdevice.h>
47 #include <linux/netdevice.h>
48 #include <linux/if_arp.h>
49 #include <linux/skbuff.h>
51 #include <linux/socket.h>
52 #include <linux/route.h>
53 #include <linux/udp.h>
54 #include <linux/proc_fs.h>
55 #include <linux/seq_file.h>
56 #include <linux/major.h>
57 #include <linux/root_dev.h>
58 #include <linux/delay.h>
59 #include <linux/nfs_fs.h>
60 #include <linux/slab.h>
61 #include <linux/export.h>
62 #include <net/net_namespace.h>
65 #include <net/ipconfig.h>
66 #include <net/route.h>
68 #include <linux/uaccess.h>
69 #include <net/checksum.h>
70 #include <asm/processor.h>
72 #if defined(CONFIG_IP_PNP_DHCP)
75 #if defined(CONFIG_IP_PNP_BOOTP) || defined(CONFIG_IP_PNP_DHCP)
76 #define IPCONFIG_BOOTP
78 #if defined(CONFIG_IP_PNP_RARP)
81 #if defined(IPCONFIG_BOOTP) || defined(IPCONFIG_RARP)
82 #define IPCONFIG_DYNAMIC
85 /* Define the friendly delay before and after opening net devices */
86 #define CONF_POST_OPEN 10 /* After opening: 10 msecs */
88 /* Define the timeout for waiting for a DHCP/BOOTP/RARP reply */
89 #define CONF_OPEN_RETRIES 2 /* (Re)open devices twice */
90 #define CONF_SEND_RETRIES 6 /* Send six requests per open */
91 #define CONF_BASE_TIMEOUT (HZ*2) /* Initial timeout: 2 seconds */
92 #define CONF_TIMEOUT_RANDOM (HZ) /* Maximum amount of randomization */
93 #define CONF_TIMEOUT_MULT *7/4 /* Rate of timeout growth */
94 #define CONF_TIMEOUT_MAX (HZ*30) /* Maximum allowed timeout */
95 #define CONF_NAMESERVERS_MAX 3 /* Maximum number of nameservers
96 - '3' from resolv.h */
97 #define CONF_NTP_SERVERS_MAX 3 /* Maximum number of NTP servers */
99 #define NONE cpu_to_be32(INADDR_NONE)
100 #define ANY cpu_to_be32(INADDR_ANY)
102 /* Wait for carrier timeout default in seconds */
103 static unsigned int carrier_timeout = 120;
106 * Public IP configuration
109 /* This is used by platforms which might be able to set the ipconfig
110 * variables using firmware environment vars. If this is set, it will
111 * ignore such firmware variables.
113 int ic_set_manually __initdata = 0; /* IPconfig parameters set manually */
115 static int ic_enable __initdata; /* IP config enabled? */
117 /* Protocol choice */
118 int ic_proto_enabled __initdata = 0
119 #ifdef IPCONFIG_BOOTP
122 #ifdef CONFIG_IP_PNP_DHCP
130 static int ic_host_name_set __initdata; /* Host name set by us? */
132 __be32 ic_myaddr = NONE; /* My IP address */
133 static __be32 ic_netmask = NONE; /* Netmask for local subnet */
134 __be32 ic_gateway = NONE; /* Gateway IP address */
136 #ifdef IPCONFIG_DYNAMIC
137 static __be32 ic_addrservaddr = NONE; /* IP Address of the IP addresses'server */
140 __be32 ic_servaddr = NONE; /* Boot server IP address */
142 __be32 root_server_addr = NONE; /* Address of NFS server */
143 u8 root_server_path[256] = { 0, }; /* Path to mount as root */
145 /* vendor class identifier */
146 static char vendor_class_identifier[253] __initdata;
148 #if defined(CONFIG_IP_PNP_DHCP)
149 static char dhcp_client_identifier[253] __initdata;
152 /* Persistent data: */
154 #ifdef IPCONFIG_DYNAMIC
155 static int ic_proto_used; /* Protocol used, if any */
157 #define ic_proto_used 0
159 static __be32 ic_nameservers[CONF_NAMESERVERS_MAX]; /* DNS Server IP addresses */
160 static __be32 ic_ntp_servers[CONF_NTP_SERVERS_MAX]; /* NTP server IP addresses */
161 static u8 ic_domain[64]; /* DNS (not NIS) domain name */
167 /* Name of user-selected boot device */
168 static char user_dev_name[IFNAMSIZ] __initdata = { 0, };
170 /* Protocols supported by available interfaces */
171 static int ic_proto_have_if __initdata;
173 /* MTU for boot device */
174 static int ic_dev_mtu __initdata;
176 #ifdef IPCONFIG_DYNAMIC
177 static DEFINE_SPINLOCK(ic_recv_lock);
178 static volatile int ic_got_reply __initdata; /* Proto(s) that replied */
181 static int ic_dhcp_msgtype __initdata; /* DHCP msg type received */
190 struct ic_device *next;
191 struct net_device *dev;
192 unsigned short flags;
197 static struct ic_device *ic_first_dev __initdata; /* List of open device */
198 static struct ic_device *ic_dev __initdata; /* Selected device */
200 static bool __init ic_is_init_dev(struct net_device *dev)
202 if (dev->flags & IFF_LOOPBACK)
204 return user_dev_name[0] ? !strcmp(dev->name, user_dev_name) :
205 (!(dev->flags & IFF_LOOPBACK) &&
206 (dev->flags & (IFF_POINTOPOINT|IFF_BROADCAST)) &&
207 strncmp(dev->name, "dummy", 5));
210 static int __init ic_open_devs(void)
212 struct ic_device *d, **last;
213 struct net_device *dev;
214 unsigned short oflags;
215 unsigned long start, next_msg;
217 last = &ic_first_dev;
220 /* bring loopback device up first */
221 for_each_netdev(&init_net, dev) {
222 if (!(dev->flags & IFF_LOOPBACK))
224 if (dev_change_flags(dev, dev->flags | IFF_UP, NULL) < 0)
225 pr_err("IP-Config: Failed to open %s\n", dev->name);
228 for_each_netdev(&init_net, dev) {
229 if (ic_is_init_dev(dev)) {
234 pr_warn("DHCP/BOOTP: Ignoring device %s, MTU %d too small\n",
235 dev->name, dev->mtu);
236 if (!(dev->flags & IFF_NOARP))
238 able &= ic_proto_enabled;
239 if (ic_proto_enabled && !able)
242 if (dev_change_flags(dev, oflags | IFF_UP, NULL) < 0) {
243 pr_err("IP-Config: Failed to open %s\n",
247 if (!(d = kmalloc(sizeof(struct ic_device), GFP_KERNEL))) {
257 get_random_bytes(&d->xid, sizeof(__be32));
260 ic_proto_have_if |= able;
261 pr_debug("IP-Config: %s UP (able=%d, xid=%08x)\n",
262 dev->name, able, d->xid);
266 /* no point in waiting if we could not bring up at least one device */
270 /* wait for a carrier on at least one device */
272 next_msg = start + msecs_to_jiffies(20000);
273 while (time_before(jiffies, start +
274 msecs_to_jiffies(carrier_timeout * 1000))) {
277 for_each_netdev(&init_net, dev)
278 if (ic_is_init_dev(dev) && netif_carrier_ok(dev))
283 if (time_before(jiffies, next_msg))
286 elapsed = jiffies_to_msecs(jiffies - start);
287 wait = (carrier_timeout * 1000 - elapsed + 500) / 1000;
288 pr_info("Waiting up to %d more seconds for network.\n", wait);
289 next_msg = jiffies + msecs_to_jiffies(20000);
297 if (user_dev_name[0])
298 pr_err("IP-Config: Device `%s' not found\n",
301 pr_err("IP-Config: No network devices available\n");
307 /* Close all network interfaces except the one we've autoconfigured, and its
308 * lowers, in case it's a stacked virtual interface.
310 static void __init ic_close_devs(void)
312 struct net_device *selected_dev = ic_dev ? ic_dev->dev : NULL;
313 struct ic_device *d, *next;
314 struct net_device *dev;
319 bool bring_down = (d != ic_dev);
320 struct net_device *lower;
321 struct list_head *iter;
327 netdev_for_each_lower_dev(selected_dev, lower, iter) {
335 pr_debug("IP-Config: Downing %s\n", dev->name);
336 dev_change_flags(dev, d->flags, NULL);
344 * Interface to various network functions.
348 set_sockaddr(struct sockaddr_in *sin, __be32 addr, __be16 port)
350 sin->sin_family = AF_INET;
351 sin->sin_addr.s_addr = addr;
352 sin->sin_port = port;
356 * Set up interface addresses and routes.
359 static int __init ic_setup_if(void)
362 struct sockaddr_in *sin = (void *) &ir.ifr_ifru.ifru_addr;
365 memset(&ir, 0, sizeof(ir));
366 strcpy(ir.ifr_ifrn.ifrn_name, ic_dev->dev->name);
367 set_sockaddr(sin, ic_myaddr, 0);
368 if ((err = devinet_ioctl(&init_net, SIOCSIFADDR, &ir)) < 0) {
369 pr_err("IP-Config: Unable to set interface address (%d)\n",
373 set_sockaddr(sin, ic_netmask, 0);
374 if ((err = devinet_ioctl(&init_net, SIOCSIFNETMASK, &ir)) < 0) {
375 pr_err("IP-Config: Unable to set interface netmask (%d)\n",
379 set_sockaddr(sin, ic_myaddr | ~ic_netmask, 0);
380 if ((err = devinet_ioctl(&init_net, SIOCSIFBRDADDR, &ir)) < 0) {
381 pr_err("IP-Config: Unable to set interface broadcast address (%d)\n",
385 /* Handle the case where we need non-standard MTU on the boot link (a network
386 * using jumbo frames, for instance). If we can't set the mtu, don't error
387 * out, we'll try to muddle along.
389 if (ic_dev_mtu != 0) {
391 if ((err = dev_set_mtu(ic_dev->dev, ic_dev_mtu)) < 0)
392 pr_err("IP-Config: Unable to set interface mtu to %d (%d)\n",
399 static int __init ic_setup_routes(void)
401 /* No need to setup device routes, only the default route... */
403 if (ic_gateway != NONE) {
407 memset(&rm, 0, sizeof(rm));
408 if ((ic_gateway ^ ic_myaddr) & ic_netmask) {
409 pr_err("IP-Config: Gateway not on directly connected network\n");
412 set_sockaddr((struct sockaddr_in *) &rm.rt_dst, 0, 0);
413 set_sockaddr((struct sockaddr_in *) &rm.rt_genmask, 0, 0);
414 set_sockaddr((struct sockaddr_in *) &rm.rt_gateway, ic_gateway, 0);
415 rm.rt_flags = RTF_UP | RTF_GATEWAY;
416 if ((err = ip_rt_ioctl(&init_net, SIOCADDRT, &rm)) < 0) {
417 pr_err("IP-Config: Cannot add default route (%d)\n",
427 * Fill in default values for all missing parameters.
430 static int __init ic_defaults(void)
433 * At this point we have no userspace running so need not
434 * claim locks on system_utsname
437 if (!ic_host_name_set)
438 sprintf(init_utsname()->nodename, "%pI4", &ic_myaddr);
440 if (root_server_addr == NONE)
441 root_server_addr = ic_servaddr;
443 if (ic_netmask == NONE) {
444 if (IN_CLASSA(ntohl(ic_myaddr)))
445 ic_netmask = htonl(IN_CLASSA_NET);
446 else if (IN_CLASSB(ntohl(ic_myaddr)))
447 ic_netmask = htonl(IN_CLASSB_NET);
448 else if (IN_CLASSC(ntohl(ic_myaddr)))
449 ic_netmask = htonl(IN_CLASSC_NET);
450 else if (IN_CLASSE(ntohl(ic_myaddr)))
451 ic_netmask = htonl(IN_CLASSE_NET);
453 pr_err("IP-Config: Unable to guess netmask for address %pI4\n",
457 pr_notice("IP-Config: Guessing netmask %pI4\n",
470 static int ic_rarp_recv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev);
472 static struct packet_type rarp_packet_type __initdata = {
473 .type = cpu_to_be16(ETH_P_RARP),
474 .func = ic_rarp_recv,
477 static inline void __init ic_rarp_init(void)
479 dev_add_pack(&rarp_packet_type);
482 static inline void __init ic_rarp_cleanup(void)
484 dev_remove_pack(&rarp_packet_type);
488 * Process received RARP packet.
491 ic_rarp_recv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
494 unsigned char *rarp_ptr;
496 unsigned char *tha; /* t for "target" */
499 if (!net_eq(dev_net(dev), &init_net))
502 skb = skb_share_check(skb, GFP_ATOMIC);
506 if (!pskb_may_pull(skb, sizeof(struct arphdr)))
509 /* Basic sanity checks can be done without the lock. */
510 rarp = (struct arphdr *)skb_transport_header(skb);
512 /* If this test doesn't pass, it's not IP, or we should
515 if (rarp->ar_hln != dev->addr_len || dev->type != ntohs(rarp->ar_hrd))
518 /* If it's not a RARP reply, delete it. */
519 if (rarp->ar_op != htons(ARPOP_RREPLY))
522 /* If it's not Ethernet, delete it. */
523 if (rarp->ar_pro != htons(ETH_P_IP))
526 if (!pskb_may_pull(skb, arp_hdr_len(dev)))
529 /* OK, it is all there and looks valid, process... */
530 rarp = (struct arphdr *)skb_transport_header(skb);
531 rarp_ptr = (unsigned char *) (rarp + 1);
533 /* One reply at a time, please. */
534 spin_lock(&ic_recv_lock);
536 /* If we already have a reply, just drop the packet */
540 /* Find the ic_device that the packet arrived on */
542 while (d && d->dev != dev)
545 goto drop_unlock; /* should never happen */
547 /* Extract variable-width fields */
548 rarp_ptr += dev->addr_len;
549 memcpy(&sip, rarp_ptr, 4);
552 rarp_ptr += dev->addr_len;
553 memcpy(&tip, rarp_ptr, 4);
555 /* Discard packets which are not meant for us. */
556 if (memcmp(tha, dev->dev_addr, dev->addr_len))
559 /* Discard packets which are not from specified server. */
560 if (ic_servaddr != NONE && ic_servaddr != sip)
563 /* We have a winner! */
565 if (ic_myaddr == NONE)
568 ic_addrservaddr = sip;
569 ic_got_reply = IC_RARP;
572 /* Show's over. Nothing to see here. */
573 spin_unlock(&ic_recv_lock);
576 /* Throw the packet out. */
583 * Send RARP request packet over a single interface.
585 static void __init ic_rarp_send_if(struct ic_device *d)
587 struct net_device *dev = d->dev;
588 arp_send(ARPOP_RREQUEST, ETH_P_RARP, 0, dev, 0, NULL,
589 dev->dev_addr, dev->dev_addr);
594 * Predefine Nameservers
596 static inline void __init ic_nameservers_predef(void)
600 for (i = 0; i < CONF_NAMESERVERS_MAX; i++)
601 ic_nameservers[i] = NONE;
604 /* Predefine NTP servers */
605 static inline void __init ic_ntp_servers_predef(void)
609 for (i = 0; i < CONF_NTP_SERVERS_MAX; i++)
610 ic_ntp_servers[i] = NONE;
614 * DHCP/BOOTP support.
617 #ifdef IPCONFIG_BOOTP
619 struct bootp_pkt { /* BOOTP packet format */
620 struct iphdr iph; /* IP header */
621 struct udphdr udph; /* UDP header */
622 u8 op; /* 1=request, 2=reply */
623 u8 htype; /* HW address type */
624 u8 hlen; /* HW address length */
625 u8 hops; /* Used only by gateways */
626 __be32 xid; /* Transaction ID */
627 __be16 secs; /* Seconds since we started */
628 __be16 flags; /* Just what it says */
629 __be32 client_ip; /* Client's IP address if known */
630 __be32 your_ip; /* Assigned IP address */
631 __be32 server_ip; /* (Next, e.g. NFS) Server's IP address */
632 __be32 relay_ip; /* IP address of BOOTP relay */
633 u8 hw_addr[16]; /* Client's HW address */
634 u8 serv_name[64]; /* Server host name */
635 u8 boot_file[128]; /* Name of boot file */
636 u8 exten[312]; /* DHCP options / BOOTP vendor extensions */
640 #define BOOTP_REQUEST 1
641 #define BOOTP_REPLY 2
643 /* DHCP message types */
644 #define DHCPDISCOVER 1
646 #define DHCPREQUEST 3
647 #define DHCPDECLINE 4
650 #define DHCPRELEASE 7
653 static int ic_bootp_recv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev);
655 static struct packet_type bootp_packet_type __initdata = {
656 .type = cpu_to_be16(ETH_P_IP),
657 .func = ic_bootp_recv,
661 * Initialize DHCP/BOOTP extension fields in the request.
664 static const u8 ic_bootp_cookie[4] = { 99, 130, 83, 99 };
669 ic_dhcp_init_options(u8 *options, struct ic_device *d)
671 u8 mt = ((ic_servaddr == NONE)
672 ? DHCPDISCOVER : DHCPREQUEST);
676 pr_debug("DHCP: Sending message type %d (%s)\n", mt, d->dev->name);
678 memcpy(e, ic_bootp_cookie, 4); /* RFC1048 Magic Cookie */
681 *e++ = 53; /* DHCP message type */
685 if (mt == DHCPREQUEST) {
686 *e++ = 54; /* Server ID (IP address) */
688 memcpy(e, &ic_servaddr, 4);
691 *e++ = 50; /* Requested IP address */
693 memcpy(e, &ic_myaddr, 4);
699 static const u8 ic_req_params[] = {
701 3, /* Default gateway */
704 15, /* Domain name */
707 40, /* NIS domain name */
708 42, /* NTP servers */
711 *e++ = 55; /* Parameter request list */
712 *e++ = sizeof(ic_req_params);
713 memcpy(e, ic_req_params, sizeof(ic_req_params));
714 e += sizeof(ic_req_params);
716 if (ic_host_name_set) {
717 *e++ = 12; /* host-name */
718 len = strlen(utsname()->nodename);
720 memcpy(e, utsname()->nodename, len);
723 if (*vendor_class_identifier) {
724 pr_info("DHCP: sending class identifier \"%s\"\n",
725 vendor_class_identifier);
726 *e++ = 60; /* Class-identifier */
727 len = strlen(vendor_class_identifier);
729 memcpy(e, vendor_class_identifier, len);
732 len = strlen(dhcp_client_identifier + 1);
733 /* the minimum length of identifier is 2, include 1 byte type,
734 * and can not be larger than the length of options
736 if (len >= 1 && len < 312 - (e - options) - 1) {
739 memcpy(e, dhcp_client_identifier, len + 1);
744 *e++ = 255; /* End of the list */
747 #endif /* IPCONFIG_DHCP */
749 static void __init ic_bootp_init_ext(u8 *e)
751 memcpy(e, ic_bootp_cookie, 4); /* RFC1048 Magic Cookie */
753 *e++ = 1; /* Subnet mask request */
756 *e++ = 3; /* Default gateway request */
759 #if CONF_NAMESERVERS_MAX > 0
760 *e++ = 6; /* (DNS) name server request */
761 *e++ = 4 * CONF_NAMESERVERS_MAX;
762 e += 4 * CONF_NAMESERVERS_MAX;
764 *e++ = 12; /* Host name request */
767 *e++ = 40; /* NIS Domain name request */
770 *e++ = 17; /* Boot path */
774 *e++ = 57; /* set extension buffer size for reply */
776 *e++ = 1; /* 128+236+8+20+14, see dhcpd sources */
779 *e++ = 255; /* End of the list */
784 * Initialize the DHCP/BOOTP mechanism.
786 static inline void __init ic_bootp_init(void)
788 /* Re-initialise all name servers and NTP servers to NONE, in case any
789 * were set via the "ip=" or "nfsaddrs=" kernel command line parameters:
790 * any IP addresses specified there will already have been decoded but
791 * are no longer needed
793 ic_nameservers_predef();
794 ic_ntp_servers_predef();
796 dev_add_pack(&bootp_packet_type);
801 * DHCP/BOOTP cleanup.
803 static inline void __init ic_bootp_cleanup(void)
805 dev_remove_pack(&bootp_packet_type);
810 * Send DHCP/BOOTP request to single interface.
812 static void __init ic_bootp_send_if(struct ic_device *d, unsigned long jiffies_diff)
814 struct net_device *dev = d->dev;
818 int hlen = LL_RESERVED_SPACE(dev);
819 int tlen = dev->needed_tailroom;
821 /* Allocate packet */
822 skb = alloc_skb(sizeof(struct bootp_pkt) + hlen + tlen + 15,
826 skb_reserve(skb, hlen);
827 b = skb_put_zero(skb, sizeof(struct bootp_pkt));
829 /* Construct IP header */
830 skb_reset_network_header(skb);
834 h->tot_len = htons(sizeof(struct bootp_pkt));
835 h->frag_off = htons(IP_DF);
837 h->protocol = IPPROTO_UDP;
838 h->daddr = htonl(INADDR_BROADCAST);
839 h->check = ip_fast_csum((unsigned char *) h, h->ihl);
841 /* Construct UDP header */
842 b->udph.source = htons(68);
843 b->udph.dest = htons(67);
844 b->udph.len = htons(sizeof(struct bootp_pkt) - sizeof(struct iphdr));
845 /* UDP checksum not calculated -- explicitly allowed in BOOTP RFC */
847 /* Construct DHCP/BOOTP header */
848 b->op = BOOTP_REQUEST;
849 if (dev->type < 256) /* check for false types */
850 b->htype = dev->type;
851 else if (dev->type == ARPHRD_FDDI)
852 b->htype = ARPHRD_ETHER;
854 pr_warn("Unknown ARP type 0x%04x for device %s\n", dev->type,
856 b->htype = dev->type; /* can cause undefined behavior */
859 /* server_ip and your_ip address are both already zero per RFC2131 */
860 b->hlen = dev->addr_len;
861 memcpy(b->hw_addr, dev->dev_addr, dev->addr_len);
862 b->secs = htons(jiffies_diff / HZ);
865 /* add DHCP options or BOOTP extensions */
867 if (ic_proto_enabled & IC_USE_DHCP)
868 ic_dhcp_init_options(b->exten, d);
871 ic_bootp_init_ext(b->exten);
873 /* Chain packet down the line... */
875 skb->protocol = htons(ETH_P_IP);
876 if (dev_hard_header(skb, dev, ntohs(skb->protocol),
877 dev->broadcast, dev->dev_addr, skb->len) < 0) {
883 if (dev_queue_xmit(skb) < 0)
889 * Copy BOOTP-supplied string
891 static int __init ic_bootp_string(char *dest, char *src, int len, int max)
897 memcpy(dest, src, len);
904 * Process BOOTP extensions.
906 static void __init ic_do_bootp_ext(u8 *ext)
914 pr_debug("DHCP/BOOTP: Got extension %d:", *ext);
915 for (c=ext+2; c<ext+2+ext[1]; c++)
916 pr_debug(" %02x", *c);
920 case 1: /* Subnet mask */
921 if (ic_netmask == NONE)
922 memcpy(&ic_netmask, ext+1, 4);
924 case 3: /* Default gateway */
925 if (ic_gateway == NONE)
926 memcpy(&ic_gateway, ext+1, 4);
928 case 6: /* DNS server */
930 if (servers > CONF_NAMESERVERS_MAX)
931 servers = CONF_NAMESERVERS_MAX;
932 for (i = 0; i < servers; i++) {
933 if (ic_nameservers[i] == NONE)
934 memcpy(&ic_nameservers[i], ext+1+4*i, 4);
937 case 12: /* Host name */
938 if (!ic_host_name_set) {
939 ic_bootp_string(utsname()->nodename, ext+1, *ext,
941 ic_host_name_set = 1;
944 case 15: /* Domain name (DNS) */
946 ic_bootp_string(ic_domain, ext+1, *ext, sizeof(ic_domain));
948 case 17: /* Root path */
949 if (!root_server_path[0])
950 ic_bootp_string(root_server_path, ext+1, *ext,
951 sizeof(root_server_path));
953 case 26: /* Interface MTU */
954 memcpy(&mtu, ext+1, sizeof(mtu));
955 ic_dev_mtu = ntohs(mtu);
957 case 40: /* NIS Domain name (_not_ DNS) */
958 ic_bootp_string(utsname()->domainname, ext+1, *ext,
961 case 42: /* NTP servers */
963 if (servers > CONF_NTP_SERVERS_MAX)
964 servers = CONF_NTP_SERVERS_MAX;
965 for (i = 0; i < servers; i++) {
966 if (ic_ntp_servers[i] == NONE)
967 memcpy(&ic_ntp_servers[i], ext+1+4*i, 4);
975 * Receive BOOTP reply.
977 static int __init ic_bootp_recv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
984 if (!net_eq(dev_net(dev), &init_net))
987 /* Perform verifications before taking the lock. */
988 if (skb->pkt_type == PACKET_OTHERHOST)
991 skb = skb_share_check(skb, GFP_ATOMIC);
995 if (!pskb_may_pull(skb,
996 sizeof(struct iphdr) +
997 sizeof(struct udphdr)))
1000 b = (struct bootp_pkt *)skb_network_header(skb);
1003 if (h->ihl != 5 || h->version != 4 || h->protocol != IPPROTO_UDP)
1006 /* Fragments are not supported */
1007 if (ip_is_fragment(h)) {
1008 net_err_ratelimited("DHCP/BOOTP: Ignoring fragmented reply\n");
1012 if (skb->len < ntohs(h->tot_len))
1015 if (ip_fast_csum((char *) h, h->ihl))
1018 if (b->udph.source != htons(67) || b->udph.dest != htons(68))
1021 if (ntohs(h->tot_len) < ntohs(b->udph.len) + sizeof(struct iphdr))
1024 len = ntohs(b->udph.len) - sizeof(struct udphdr);
1025 ext_len = len - (sizeof(*b) -
1026 sizeof(struct iphdr) -
1027 sizeof(struct udphdr) -
1032 /* Ok the front looks good, make sure we can get at the rest. */
1033 if (!pskb_may_pull(skb, skb->len))
1036 b = (struct bootp_pkt *)skb_network_header(skb);
1039 /* One reply at a time, please. */
1040 spin_lock(&ic_recv_lock);
1042 /* If we already have a reply, just drop the packet */
1046 /* Find the ic_device that the packet arrived on */
1048 while (d && d->dev != dev)
1051 goto drop_unlock; /* should never happen */
1053 /* Is it a reply to our BOOTP request? */
1054 if (b->op != BOOTP_REPLY ||
1056 net_err_ratelimited("DHCP/BOOTP: Reply not for us on %s, op[%x] xid[%x]\n",
1057 d->dev->name, b->op, b->xid);
1061 /* Parse extensions */
1063 !memcmp(b->exten, ic_bootp_cookie, 4)) { /* Check magic cookie */
1064 u8 *end = (u8 *) b + ntohs(b->iph.tot_len);
1067 #ifdef IPCONFIG_DHCP
1068 if (ic_proto_enabled & IC_USE_DHCP) {
1069 __be32 server_id = NONE;
1073 while (ext < end && *ext != 0xff) {
1075 if (*opt == 0) /* Padding */
1081 case 53: /* Message type */
1085 case 54: /* Server ID (IP address) */
1087 memcpy(&server_id, opt + 2, 4);
1092 pr_debug("DHCP: Got message type %d (%s)\n", mt, d->dev->name);
1096 /* While in the process of accepting one offer,
1097 * ignore all others.
1099 if (ic_myaddr != NONE)
1102 /* Let's accept that offer. */
1103 ic_myaddr = b->your_ip;
1104 ic_servaddr = server_id;
1105 pr_debug("DHCP: Offered address %pI4 by server %pI4\n",
1106 &ic_myaddr, &b->iph.saddr);
1107 /* The DHCP indicated server address takes
1108 * precedence over the bootp header one if
1109 * they are different.
1111 if ((server_id != NONE) &&
1112 (b->server_ip != server_id))
1113 b->server_ip = ic_servaddr;
1117 if (memcmp(dev->dev_addr, b->hw_addr, dev->addr_len) != 0)
1124 /* Urque. Forget it*/
1130 ic_dhcp_msgtype = mt;
1133 #endif /* IPCONFIG_DHCP */
1136 while (ext < end && *ext != 0xff) {
1138 if (*opt == 0) /* Padding */
1142 ic_do_bootp_ext(opt);
1146 /* We have a winner! */
1148 ic_myaddr = b->your_ip;
1149 ic_servaddr = b->server_ip;
1150 ic_addrservaddr = b->iph.saddr;
1151 if (ic_gateway == NONE && b->relay_ip)
1152 ic_gateway = b->relay_ip;
1153 if (ic_nameservers[0] == NONE)
1154 ic_nameservers[0] = ic_servaddr;
1155 ic_got_reply = IC_BOOTP;
1158 /* Show's over. Nothing to see here. */
1159 spin_unlock(&ic_recv_lock);
1162 /* Throw the packet out. */
1173 * Dynamic IP configuration -- DHCP, BOOTP, RARP.
1176 #ifdef IPCONFIG_DYNAMIC
1178 static int __init ic_dynamic(void)
1181 struct ic_device *d;
1182 unsigned long start_jiffies, timeout, jiff;
1183 int do_bootp = ic_proto_have_if & IC_BOOTP;
1184 int do_rarp = ic_proto_have_if & IC_RARP;
1187 * If none of DHCP/BOOTP/RARP was selected, return with an error.
1188 * This routine gets only called when some pieces of information
1189 * are missing, and without DHCP/BOOTP/RARP we are unable to get it.
1191 if (!ic_proto_enabled) {
1192 pr_err("IP-Config: Incomplete network configuration information\n");
1196 #ifdef IPCONFIG_BOOTP
1197 if ((ic_proto_enabled ^ ic_proto_have_if) & IC_BOOTP)
1198 pr_err("DHCP/BOOTP: No suitable device found\n");
1200 #ifdef IPCONFIG_RARP
1201 if ((ic_proto_enabled ^ ic_proto_have_if) & IC_RARP)
1202 pr_err("RARP: No suitable device found\n");
1205 if (!ic_proto_have_if)
1206 /* Error message already printed */
1212 #ifdef IPCONFIG_BOOTP
1216 #ifdef IPCONFIG_RARP
1222 * Send requests and wait, until we get an answer. This loop
1223 * seems to be a terrible waste of CPU time, but actually there is
1224 * only one process running at all, so we don't need to use any
1225 * scheduler functions.
1226 * [Actually we could now, but the nothing else running note still
1229 pr_notice("Sending %s%s%s requests .",
1231 ? ((ic_proto_enabled & IC_USE_DHCP) ? "DHCP" : "BOOTP") : "",
1232 (do_bootp && do_rarp) ? " and " : "",
1233 do_rarp ? "RARP" : "");
1235 start_jiffies = jiffies;
1237 retries = CONF_SEND_RETRIES;
1238 get_random_bytes(&timeout, sizeof(timeout));
1239 timeout = CONF_BASE_TIMEOUT + (timeout % (unsigned int) CONF_TIMEOUT_RANDOM);
1241 #ifdef IPCONFIG_BOOTP
1242 if (do_bootp && (d->able & IC_BOOTP))
1243 ic_bootp_send_if(d, jiffies - start_jiffies);
1245 #ifdef IPCONFIG_RARP
1246 if (do_rarp && (d->able & IC_RARP))
1251 jiff = jiffies + timeout;
1252 while (time_before(jiffies, jiff) && !ic_got_reply)
1253 schedule_timeout_uninterruptible(1);
1255 #ifdef IPCONFIG_DHCP
1256 /* DHCP isn't done until we get a DHCPACK. */
1257 if ((ic_got_reply & IC_BOOTP) &&
1258 (ic_proto_enabled & IC_USE_DHCP) &&
1259 ic_dhcp_msgtype != DHCPACK) {
1261 /* continue on device that got the reply */
1266 #endif /* IPCONFIG_DHCP */
1277 pr_cont(" timed out!\n");
1283 timeout = timeout CONF_TIMEOUT_MULT;
1284 if (timeout > CONF_TIMEOUT_MAX)
1285 timeout = CONF_TIMEOUT_MAX;
1290 #ifdef IPCONFIG_BOOTP
1294 #ifdef IPCONFIG_RARP
1299 if (!ic_got_reply) {
1304 pr_info("IP-Config: Got %s answer from %pI4, my address is %pI4\n",
1305 ((ic_got_reply & IC_RARP) ? "RARP"
1306 : (ic_proto_enabled & IC_USE_DHCP) ? "DHCP" : "BOOTP"),
1307 &ic_addrservaddr, &ic_myaddr);
1312 #endif /* IPCONFIG_DYNAMIC */
1314 #ifdef CONFIG_PROC_FS
1315 /* proc_dir_entry for /proc/net/ipconfig */
1316 static struct proc_dir_entry *ipconfig_dir;
1319 static int pnp_seq_show(struct seq_file *seq, void *v)
1323 if (ic_proto_used & IC_PROTO)
1324 seq_printf(seq, "#PROTO: %s\n",
1325 (ic_proto_used & IC_RARP) ? "RARP"
1326 : (ic_proto_used & IC_USE_DHCP) ? "DHCP" : "BOOTP");
1328 seq_puts(seq, "#MANUAL\n");
1332 "domain %s\n", ic_domain);
1333 for (i = 0; i < CONF_NAMESERVERS_MAX; i++) {
1334 if (ic_nameservers[i] != NONE)
1335 seq_printf(seq, "nameserver %pI4\n",
1336 &ic_nameservers[i]);
1338 if (ic_servaddr != NONE)
1339 seq_printf(seq, "bootserver %pI4\n",
1344 /* Create the /proc/net/ipconfig directory */
1345 static int __init ipconfig_proc_net_init(void)
1347 ipconfig_dir = proc_net_mkdir(&init_net, "ipconfig", init_net.proc_net);
1354 /* Create a new file under /proc/net/ipconfig */
1355 static int ipconfig_proc_net_create(const char *name,
1356 const struct proc_ops *proc_ops)
1359 struct proc_dir_entry *p;
1364 pname = kasprintf(GFP_KERNEL, "%s%s", "ipconfig/", name);
1368 p = proc_create(pname, 0444, init_net.proc_net, proc_ops);
1376 /* Write NTP server IP addresses to /proc/net/ipconfig/ntp_servers */
1377 static int ntp_servers_show(struct seq_file *seq, void *v)
1381 for (i = 0; i < CONF_NTP_SERVERS_MAX; i++) {
1382 if (ic_ntp_servers[i] != NONE)
1383 seq_printf(seq, "%pI4\n", &ic_ntp_servers[i]);
1387 DEFINE_PROC_SHOW_ATTRIBUTE(ntp_servers);
1388 #endif /* CONFIG_PROC_FS */
1391 * Extract IP address from the parameter string if needed. Note that we
1392 * need to have root_server_addr set _before_ IPConfig gets called as it
1395 __be32 __init root_nfs_parse_addr(char *name)
1402 while (octets < 4) {
1403 while (*cp >= '0' && *cp <= '9')
1405 if (cp == cq || cp - cq > 3)
1407 if (*cp == '.' || octets == 3)
1413 if (octets == 4 && (*cp == ':' || *cp == '\0')) {
1416 addr = in_aton(name);
1417 memmove(name, cp, strlen(cp) + 1);
1424 #define DEVICE_WAIT_MAX 12 /* 12 seconds */
1426 static int __init wait_for_devices(void)
1430 for (i = 0; i < DEVICE_WAIT_MAX; i++) {
1431 struct net_device *dev;
1434 /* make sure deferred device probes are finished */
1435 wait_for_device_probe();
1438 for_each_netdev(&init_net, dev) {
1439 if (ic_is_init_dev(dev)) {
1453 * IP Autoconfig dispatcher.
1456 static int __init ip_auto_config(void)
1459 #ifdef IPCONFIG_DYNAMIC
1460 int retries = CONF_OPEN_RETRIES;
1463 unsigned int i, count;
1465 /* Initialise all name servers and NTP servers to NONE (but only if the
1466 * "ip=" or "nfsaddrs=" kernel command line parameters weren't decoded,
1467 * otherwise we'll overwrite the IP addresses specified there)
1469 if (ic_set_manually == 0) {
1470 ic_nameservers_predef();
1471 ic_ntp_servers_predef();
1474 #ifdef CONFIG_PROC_FS
1475 proc_create_single("pnp", 0444, init_net.proc_net, pnp_seq_show);
1477 if (ipconfig_proc_net_init() == 0)
1478 ipconfig_proc_net_create("ntp_servers", &ntp_servers_proc_ops);
1479 #endif /* CONFIG_PROC_FS */
1484 pr_debug("IP-Config: Entered.\n");
1485 #ifdef IPCONFIG_DYNAMIC
1488 /* Wait for devices to appear */
1489 err = wait_for_devices();
1493 /* Setup all network devices */
1494 err = ic_open_devs();
1498 /* Give drivers a chance to settle */
1499 msleep(CONF_POST_OPEN);
1502 * If the config information is insufficient (e.g., our IP address or
1503 * IP address of the boot server is missing or we have multiple network
1504 * interfaces and no default was set), use BOOTP or RARP to get the
1507 if (ic_myaddr == NONE ||
1508 #if defined(CONFIG_ROOT_NFS) || defined(CONFIG_CIFS_ROOT)
1509 (root_server_addr == NONE &&
1510 ic_servaddr == NONE &&
1511 (ROOT_DEV == Root_NFS || ROOT_DEV == Root_CIFS)) ||
1513 ic_first_dev->next) {
1514 #ifdef IPCONFIG_DYNAMIC
1515 if (ic_dynamic() < 0) {
1519 * I don't know why, but sometimes the
1520 * eepro100 driver (at least) gets upset and
1521 * doesn't work the first time it's opened.
1522 * But then if you close it and reopen it, it
1523 * works just fine. So we need to try that at
1524 * least once before giving up.
1526 * Also, if the root will be NFS-mounted, we
1527 * have nowhere to go if DHCP fails. So we
1528 * just have to keep trying forever.
1532 #ifdef CONFIG_ROOT_NFS
1533 if (ROOT_DEV == Root_NFS) {
1534 pr_err("IP-Config: Retrying forever (NFS root)...\n");
1538 #ifdef CONFIG_CIFS_ROOT
1539 if (ROOT_DEV == Root_CIFS) {
1540 pr_err("IP-Config: Retrying forever (CIFS root)...\n");
1546 pr_err("IP-Config: Reopening network devices...\n");
1550 /* Oh, well. At least we tried. */
1551 pr_err("IP-Config: Auto-configuration of network failed\n");
1554 #else /* !DYNAMIC */
1555 pr_err("IP-Config: Incomplete network configuration information\n");
1558 #endif /* IPCONFIG_DYNAMIC */
1560 /* Device selected manually or only one device -> use it */
1561 ic_dev = ic_first_dev;
1564 addr = root_nfs_parse_addr(root_server_path);
1565 if (root_server_addr == NONE)
1566 root_server_addr = addr;
1569 * Use defaults wherever applicable.
1571 if (ic_defaults() < 0)
1575 * Record which protocol was actually used.
1577 #ifdef IPCONFIG_DYNAMIC
1578 ic_proto_used = ic_got_reply | (ic_proto_enabled & IC_USE_DHCP);
1581 #ifndef IPCONFIG_SILENT
1583 * Clue in the operator.
1585 pr_info("IP-Config: Complete:\n");
1587 pr_info(" device=%s, hwaddr=%*phC, ipaddr=%pI4, mask=%pI4, gw=%pI4\n",
1588 ic_dev->dev->name, ic_dev->dev->addr_len, ic_dev->dev->dev_addr,
1589 &ic_myaddr, &ic_netmask, &ic_gateway);
1590 pr_info(" host=%s, domain=%s, nis-domain=%s\n",
1591 utsname()->nodename, ic_domain, utsname()->domainname);
1592 pr_info(" bootserver=%pI4, rootserver=%pI4, rootpath=%s",
1593 &ic_servaddr, &root_server_addr, root_server_path);
1595 pr_cont(", mtu=%d", ic_dev_mtu);
1596 /* Name servers (if any): */
1597 for (i = 0, count = 0; i < CONF_NAMESERVERS_MAX; i++) {
1598 if (ic_nameservers[i] != NONE) {
1600 pr_info(" nameserver%u=%pI4",
1601 i, &ic_nameservers[i]);
1603 pr_cont(", nameserver%u=%pI4",
1604 i, &ic_nameservers[i]);
1608 if ((i + 1 == CONF_NAMESERVERS_MAX) && count > 0)
1611 /* NTP servers (if any): */
1612 for (i = 0, count = 0; i < CONF_NTP_SERVERS_MAX; i++) {
1613 if (ic_ntp_servers[i] != NONE) {
1615 pr_info(" ntpserver%u=%pI4",
1616 i, &ic_ntp_servers[i]);
1618 pr_cont(", ntpserver%u=%pI4",
1619 i, &ic_ntp_servers[i]);
1623 if ((i + 1 == CONF_NTP_SERVERS_MAX) && count > 0)
1626 #endif /* !SILENT */
1629 * Close all network devices except the device we've
1630 * autoconfigured and set up routes.
1632 if (ic_setup_if() < 0 || ic_setup_routes() < 0)
1642 late_initcall(ip_auto_config);
1646 * Decode any IP configuration options in the "ip=" or "nfsaddrs=" kernel
1647 * command line parameter. See Documentation/admin-guide/nfs/nfsroot.rst.
1649 static int __init ic_proto_name(char *name)
1651 if (!strcmp(name, "on") || !strcmp(name, "any")) {
1654 if (!strcmp(name, "off") || !strcmp(name, "none")) {
1657 #ifdef CONFIG_IP_PNP_DHCP
1658 else if (!strncmp(name, "dhcp", 4)) {
1661 ic_proto_enabled &= ~IC_RARP;
1662 client_id = strstr(name, "dhcp,");
1666 client_id = client_id + 5;
1667 v = strchr(client_id, ',');
1671 if (kstrtou8(client_id, 0, dhcp_client_identifier))
1672 pr_debug("DHCP: Invalid client identifier type\n");
1673 strncpy(dhcp_client_identifier + 1, v + 1, 251);
1679 #ifdef CONFIG_IP_PNP_BOOTP
1680 else if (!strcmp(name, "bootp")) {
1681 ic_proto_enabled &= ~(IC_RARP | IC_USE_DHCP);
1685 #ifdef CONFIG_IP_PNP_RARP
1686 else if (!strcmp(name, "rarp")) {
1687 ic_proto_enabled &= ~(IC_BOOTP | IC_USE_DHCP);
1691 #ifdef IPCONFIG_DYNAMIC
1692 else if (!strcmp(name, "both")) {
1693 ic_proto_enabled &= ~IC_USE_DHCP; /* backward compat :-( */
1700 static int __init ip_auto_config_setup(char *addrs)
1705 ic_set_manually = 1;
1709 * If any dhcp, bootp etc options are set, leave autoconfig on
1710 * and skip the below static IP processing.
1712 if (ic_proto_name(addrs))
1715 /* If no static IP is given, turn off autoconfig and bail. */
1717 strcmp(addrs, "off") == 0 ||
1718 strcmp(addrs, "none") == 0) {
1723 /* Initialise all name servers and NTP servers to NONE */
1724 ic_nameservers_predef();
1725 ic_ntp_servers_predef();
1727 /* Parse string for static IP assignment. */
1730 if ((cp = strchr(ip, ':')))
1732 if (strlen(ip) > 0) {
1733 pr_debug("IP-Config: Parameter #%d: `%s'\n", num, ip);
1736 if ((ic_myaddr = in_aton(ip)) == ANY)
1740 if ((ic_servaddr = in_aton(ip)) == ANY)
1744 if ((ic_gateway = in_aton(ip)) == ANY)
1748 if ((ic_netmask = in_aton(ip)) == ANY)
1752 if ((dp = strchr(ip, '.'))) {
1754 strlcpy(utsname()->domainname, dp,
1755 sizeof(utsname()->domainname));
1757 strlcpy(utsname()->nodename, ip,
1758 sizeof(utsname()->nodename));
1759 ic_host_name_set = 1;
1762 strlcpy(user_dev_name, ip, sizeof(user_dev_name));
1765 if (ic_proto_name(ip) == 0 &&
1766 ic_myaddr == NONE) {
1771 if (CONF_NAMESERVERS_MAX >= 1) {
1772 ic_nameservers[0] = in_aton(ip);
1773 if (ic_nameservers[0] == ANY)
1774 ic_nameservers[0] = NONE;
1778 if (CONF_NAMESERVERS_MAX >= 2) {
1779 ic_nameservers[1] = in_aton(ip);
1780 if (ic_nameservers[1] == ANY)
1781 ic_nameservers[1] = NONE;
1785 if (CONF_NTP_SERVERS_MAX >= 1) {
1786 ic_ntp_servers[0] = in_aton(ip);
1787 if (ic_ntp_servers[0] == ANY)
1788 ic_ntp_servers[0] = NONE;
1799 __setup("ip=", ip_auto_config_setup);
1801 static int __init nfsaddrs_config_setup(char *addrs)
1803 return ip_auto_config_setup(addrs);
1805 __setup("nfsaddrs=", nfsaddrs_config_setup);
1807 static int __init vendor_class_identifier_setup(char *addrs)
1809 if (strlcpy(vendor_class_identifier, addrs,
1810 sizeof(vendor_class_identifier))
1811 >= sizeof(vendor_class_identifier))
1812 pr_warn("DHCP: vendorclass too long, truncated to \"%s\"\n",
1813 vendor_class_identifier);
1816 __setup("dhcpclass=", vendor_class_identifier_setup);
1818 static int __init set_carrier_timeout(char *str)
1825 ret = kstrtouint(str, 0, &carrier_timeout);
1831 __setup("carrier_timeout=", set_carrier_timeout);