usr/kinit/ipconfig/bootp_proto.c - maze/klibc - Git at Google

 /*
  * BOOTP packet protocol handling.
  */
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
 #include <netinet/in.h>

 #include "ipconfig.h"
 #include "netdev.h"
 #include "bootp_packet.h"
 #include "bootp_proto.h"
 #include "packet.h"

 static uint8_t bootp_options[312] = {
 	[  0] = 99, 130, 83, 99,/* RFC1048 magic cookie */
 	[  4] = 1, 4,		/*   4-  9 subnet mask */
 	[ 10] = 3, 4,		/*  10- 15 default gateway */
 	[ 16] = 5, 8,		/*  16- 25 nameserver */
 	[ 26] = 12, 32,		/*  26- 59 host name */
 	[ 60] = 40, 32,		/*  60- 95 nis domain name */
 	[ 96] = 17, 40,		/*  96-137 boot path */
 	[138] = 57, 2, 1, 150,	/* 138-141 extension buffer */
 	[142] = 255,		/* end of list */
 };

 /*
  * Send a plain bootp request packet with options
  */
 int bootp_send_request(struct netdev *dev)
 {
 	struct bootp_hdr bootp;
 	struct iovec iov[] = {
 		/* [0] = ip + udp headers */
 		[1] = {&bootp, sizeof(bootp)},
 		[2] = {bootp_options, 312}
 	};

 	memset(&bootp, 0, sizeof(struct bootp_hdr));

 	bootp.op	= BOOTP_REQUEST, bootp.htype = dev->hwtype;
 	bootp.hlen	= dev->hwlen;
 	bootp.xid	= dev->bootp.xid;
 	bootp.ciaddr	= dev->ip_addr;
 	bootp.secs	= htons(time(NULL) - dev->open_time);
 	memcpy(bootp.chaddr, dev->hwaddr, 16);

 	dprintf("-> bootp xid 0x%08x secs 0x%08x ",
 		bootp.xid, ntohs(bootp.secs));

 	return packet_send(dev, iov, 2);
 }

 /*
  * DESCRIPTION
  *  bootp_ext119_decode() decodes Domain Search Option data.
  *  The decoded string is separated with ' '.
  *  For example, it is either "foo.bar.baz. bar.baz.", "foo.bar.", or "foo.".
  *
  * ARGUMENTS
  *  const uint8_t *ext
  *   *ext is a pointer to a DHCP Domain Search Option data. *ext does not
  *   include a tag(code) octet and a length octet in DHCP options.
  *   For example, if *ext is {3, 'f', 'o', 'o', 0}, this function returns
  *   a pointer to a "foo." string.
  *
  *  int16_t ext_size
  *   ext_size is the memory size of *ext. For example,
  *   if *ext is {3, 'f', 'o', 'o', 0}, ext_size must be 5.
  *
  *  uint8_t *tmp
  *   *tmp is a pointer to a temporary memory space for decoding.
  *   The memory size must be equal to or more than ext_size.
  *   'memset(tmp, 0, sizeof(tmp));' is not required, but values in *tmp
  *   are changed in decoding process.
  *
  * RETURN VALUE
  *  if OK, a pointer to a decoded string malloc-ed
  *  else , NULL
  *
  * SEE ALSO RFC3397
  */
 static char *bootp_ext119_decode(const void *ext, int16_t ext_size, void *tmp)
 {
 	uint8_t *u8ext;
 	int_fast32_t i;
 	int_fast32_t decoded_size;
 	int_fast8_t currentdomain_is_singledot;

 	/* only for validating *ext */
 	uint8_t *is_pointee;
 	int_fast32_t is_pointee_size;

 	/* only for structing a decoded string */
 	char *decoded_str;
 	int_fast32_t dst_i;

 	if (ext == NULL || ext_size <= 0 || tmp == NULL)
 		return NULL;

 	u8ext = (uint8_t *)ext;
 	is_pointee = tmp;
 	memset(is_pointee, 0, (size_t)ext_size);
 	is_pointee_size = 0;

 	/*
 	 * validate the format of *ext and
 	 * calculate the memory size for a decoded string
 	 */
 	i = 0;
 	decoded_size = 0;
 	currentdomain_is_singledot = 1;
 	while (1) {
 		if (i >= ext_size)
 			return NULL;

 		if (u8ext[i] == 0) {
 			/* Zero-ending */
 			if (currentdomain_is_singledot)
 				decoded_size++; /* for '.' */
 			decoded_size++; /* for ' ' or '\0' */
 			currentdomain_is_singledot = 1;
 			i++;
 			if (i == ext_size)
 				break;
 			is_pointee_size = i;
 		} else if (u8ext[i] < 0x40) {
 			/* Label(sub-domain string) */
 			int j;

 			/* loosely validate characters for domain names */
 			if (i + u8ext[i] >= ext_size)
 				return NULL;
 			for (j = i + 1; j <= i + u8ext[i]; j++)
 				if (!(u8ext[j] == '-' ||
 				     ('0' <= u8ext[j] && u8ext[j] <= '9') ||
 				     ('A' <= u8ext[j] && u8ext[j] <= 'Z') ||
 				     ('a' <= u8ext[j] && u8ext[j] <= 'z')))
 					return NULL;

 			is_pointee[i] = 1;
 			decoded_size += u8ext[i] + 1; /* for Label + '.' */
 			currentdomain_is_singledot = 0;
 			i += u8ext[i] + 1;
 		} else if (u8ext[i] < 0xc0)
 			return NULL;

 		else {
 			/* Compression-pointer (to a prior Label) */
 			int_fast32_t p;

 			if (i + 1 >= ext_size)
 				return NULL;

 			p = ((0x3f & u8ext[i]) << 8) + u8ext[i + 1];
 			if (!(p < is_pointee_size && is_pointee[p]))
 				return NULL;

 			while (1) {
 				/* u8ext[p] was validated */
 				if (u8ext[p] == 0) {
 					/* Zero-ending */
 					decoded_size++;
 					break;
 				} else if (u8ext[p] < 0x40) {
 					/* Label(sub-domain string) */
 					decoded_size += u8ext[p] + 1;
 					p += u8ext[p] + 1;
 				} else {
 					/* Compression-pointer */
 					p = ((0x3f & u8ext[p]) << 8)
 						+ u8ext[p + 1];
 				}
 			}

 			currentdomain_is_singledot = 1;
 			i += 2;
 			if (i == ext_size)
 				break;
 			is_pointee_size = i;
 		}
 	}


 	/*
 	 * construct a decoded string
 	 */
 	decoded_str = malloc(decoded_size);
 	if (decoded_str == NULL)
 		return NULL;

 	i = 0;
 	dst_i = 0;
 	currentdomain_is_singledot = 1;
 	while (1) {
 		if (u8ext[i] == 0) {
 			/* Zero-ending */
 			if (currentdomain_is_singledot) {
 				if (dst_i != 0)
 					dst_i++;
 				decoded_str[dst_i] = '.';
 			}
 			dst_i++;
 			decoded_str[dst_i] = ' ';

 			currentdomain_is_singledot = 1;
 			i++;
 			if (i == ext_size)
 				break;
 		} else if (u8ext[i] < 0x40) {
 			/* Label(sub-domain string) */
 			if (dst_i != 0)
 				dst_i++;
 			memcpy(&decoded_str[dst_i], &u8ext[i + 1],
 			       (size_t)u8ext[i]);
 			dst_i += u8ext[i];
 			decoded_str[dst_i] = '.';

 			currentdomain_is_singledot = 0;
 			i += u8ext[i] + 1;
 		} else {
 			/* Compression-pointer (to a prior Label) */
 			int_fast32_t p;

 			p = ((0x3f & u8ext[i]) << 8) + u8ext[i + 1];
 			while (1) {
 				if (u8ext[p] == 0) {
 					/* Zero-ending */
 					decoded_str[dst_i++] = '.';
 					decoded_str[dst_i] = ' ';
 					break;
 				} else if (u8ext[p] < 0x40) {
 					/* Label(sub-domain string) */
 					dst_i++;
 					memcpy(&decoded_str[dst_i],
 					       &u8ext[p + 1],
 					       (size_t)u8ext[p]);
 					dst_i += u8ext[p];
 					decoded_str[dst_i] = '.';

 					p += u8ext[p] + 1;
 				} else {
 					/* Compression-pointer */
 					p = ((0x3f & u8ext[p]) << 8)
 						+ u8ext[p + 1];
 				}
 			}

 			currentdomain_is_singledot = 1;
 			i += 2;
 			if (i == ext_size)
 				break;
 		}
 	}
 	decoded_str[dst_i] = '\0';
 #ifdef DEBUG
 	if (dst_i + 1 != decoded_size) {
 		dprintf("bug:%s():bottom: malloc(%ld), write(%ld)\n",
 			__func__, (long)decoded_size, (long)(dst_i + 1));
 		exit(1);
 	}
 #endif
 	return decoded_str;
 }

 /*
  * Parse a bootp reply packet
  */
 int bootp_parse(struct netdev *dev, struct bootp_hdr *hdr,
 		uint8_t *exts, int extlen)
 {
 	uint8_t ext119_buf[BOOTP_EXTS_SIZE];
 	int16_t ext119_len = 0;

 	dev->bootp.gateway	= hdr->giaddr;
 	dev->ip_addr		= hdr->yiaddr;
 	dev->ip_server		= hdr->siaddr;
 	dev->ip_netmask		= INADDR_ANY;
 	dev->ip_broadcast	= INADDR_ANY;
 	dev->ip_gateway		= hdr->giaddr;
 	dev->ip_nameserver[0]	= INADDR_ANY;
 	dev->ip_nameserver[1]	= INADDR_ANY;
 	dev->hostname[0]	= '\0';
 	dev->nisdomainname[0]	= '\0';
 	dev->bootpath[0]	= '\0';
 	memcpy(&dev->filename, &hdr->boot_file, FNLEN);

 	if (extlen >= 4 && exts[0] == 99 && exts[1] == 130 &&
 	    exts[2] == 83 && exts[3] == 99) {
 		uint8_t *ext;

 		for (ext = exts + 4; ext - exts < extlen;) {
 			int len;
 			uint8_t opt = *ext++;

 			if (opt == 0)
 				continue;
 			else if (opt == 255)
 				break;

 			if (ext - exts >= extlen)
 				break;
 			len = *ext++;

 			if (ext - exts + len > extlen)
 				break;
 			switch (opt) {
 			case 1:	/* subnet mask */
 				if (len == 4)
 					memcpy(&dev->ip_netmask, ext, 4);
 				break;
 			case 3:	/* default gateway */
 				if (len >= 4)
 					memcpy(&dev->ip_gateway, ext, 4);
 				break;
 			case 6:	/* DNS server */
 				if (len >= 4)
 					memcpy(&dev->ip_nameserver, ext,
 					       len >= 8 ? 8 : 4);
 				break;
 			case 12:	/* host name */
 				if (len > sizeof(dev->hostname) - 1)
 					len = sizeof(dev->hostname) - 1;
 				memcpy(&dev->hostname, ext, len);
 				dev->hostname[len] = '\0';
 				break;
 			case 15:	/* domain name */
 				if (len > sizeof(dev->dnsdomainname) - 1)
 					len = sizeof(dev->dnsdomainname) - 1;
 				memcpy(&dev->dnsdomainname, ext, len);
 				dev->dnsdomainname[len] = '\0';
 				break;
 			case 17:	/* root path */
 				if (len > sizeof(dev->bootpath) - 1)
 					len = sizeof(dev->bootpath) - 1;
 				memcpy(&dev->bootpath, ext, len);
 				dev->bootpath[len] = '\0';
 				break;
 			case 26:	/* interface MTU */
 				if (len == 2)
 					dev->mtu = (ext[0] << 8) + ext[1];
 				break;
 			case 28:	/* broadcast addr */
 				if (len == 4)
 					memcpy(&dev->ip_broadcast, ext, 4);
 				break;
 			case 40:	/* NIS domain name */
 				if (len > sizeof(dev->nisdomainname) - 1)
 					len = sizeof(dev->nisdomainname) - 1;
 				memcpy(&dev->nisdomainname, ext, len);
 				dev->nisdomainname[len] = '\0';
 				break;
 			case 54:	/* server identifier */
 				if (len == 4 && !dev->ip_server)
 					memcpy(&dev->ip_server, ext, 4);
 				break;
 			case 119:	/* Domain Search Option */
 				if (ext119_len >= 0 &&
 				    ext119_len + len <= sizeof(ext119_buf)) {
 					memcpy(ext119_buf + ext119_len,
 					       ext, len);
 					ext119_len += len;
 				} else
 					ext119_len = -1;

 				break;
 			}

 			ext += len;
 		}
 	}
 	if (ext119_len > 0) {
 		char *ret;
 		uint8_t ext119_tmp[BOOTP_EXTS_SIZE];

 		ret = bootp_ext119_decode(ext119_buf, ext119_len, ext119_tmp);
 		if (ret != NULL) {
 			if (dev->domainsearch != NULL)
 				free(dev->domainsearch);
 			dev->domainsearch = ret;
 		}
 	}

 	/*
 	 * Got packet.
 	 */
 	return 1;
 }

 /*
  * Receive a bootp reply and parse packet
  * Returns:
  *-1 = Error in packet_recv, try again later
  * 0 = Unexpected packet, discarded
  * 1 = Correctly received and parsed packet
  */
 int bootp_recv_reply(struct netdev *dev)
 {
 	struct bootp_hdr bootp;
 	uint8_t bootp_options[BOOTP_EXTS_SIZE];
 	struct iovec iov[] = {
 		/* [0] = ip + udp headers */
 		[1] = {&bootp, sizeof(struct bootp_hdr)},
 		[2] = {bootp_options, sizeof(bootp_options)}
 	};
 	int ret;

 	ret = packet_recv(dev, iov, 3);
 	if (ret <= 0)
 		return ret;

 	if (ret < sizeof(struct bootp_hdr) ||
 	    bootp.op != BOOTP_REPLY ||	/* RFC951 7.5 */
 	    bootp.xid != dev->bootp.xid ||
 	    memcmp(bootp.chaddr, dev->hwaddr, 16))
 		return 0;

 	ret -= sizeof(struct bootp_hdr);

 	return bootp_parse(dev, &bootp, bootp_options, ret);
 }

 /*
  * Initialise interface for bootp.
  */
 int bootp_init_if(struct netdev *dev)
 {
 	short flags;

 	/*
 	 * Get the device flags
 	 */
 	if (netdev_getflags(dev, &flags))
 		return -1;

 	/*
 	 * We can't do DHCP nor BOOTP if this device
 	 * doesn't support broadcast.
 	 */
 	if (dev->mtu < 364 || (flags & IFF_BROADCAST) == 0) {
 		dev->caps &= ~(CAP_BOOTP | CAP_DHCP);
 		return 0;
 	}

 	/*
 	 * Get a random XID
 	 */
 	dev->bootp.xid = (uint32_t) lrand48();
 	dev->open_time = time(NULL);

 	return 0;
 }
	/*
	* BOOTP packet protocol handling.
	*/
	#include <sys/types.h>
	#include <sys/uio.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <time.h>
	#include <unistd.h>
	#include <netinet/in.h>

	#include "ipconfig.h"
	#include "netdev.h"
	#include "bootp_packet.h"
	#include "bootp_proto.h"
	#include "packet.h"

	static uint8_t bootp_options[312] = {
	[ 0] = 99, 130, 83, 99,/* RFC1048 magic cookie */
	[ 4] = 1, 4, /* 4- 9 subnet mask */
	[ 10] = 3, 4, /* 10- 15 default gateway */
	[ 16] = 5, 8, /* 16- 25 nameserver */
	[ 26] = 12, 32, /* 26- 59 host name */
	[ 60] = 40, 32, /* 60- 95 nis domain name */
	[ 96] = 17, 40, /* 96-137 boot path */
	[138] = 57, 2, 1, 150, /* 138-141 extension buffer */
	[142] = 255, /* end of list */
	};

	/*
	* Send a plain bootp request packet with options
	*/
	int bootp_send_request(struct netdev *dev)
	{
	struct bootp_hdr bootp;
	struct iovec iov[] = {
	/* [0] = ip + udp headers */
	[1] = {&bootp, sizeof(bootp)},
	[2] = {bootp_options, 312}
	};

	memset(&bootp, 0, sizeof(struct bootp_hdr));

	bootp.op = BOOTP_REQUEST, bootp.htype = dev->hwtype;
	bootp.hlen = dev->hwlen;
	bootp.xid = dev->bootp.xid;
	bootp.ciaddr = dev->ip_addr;
	bootp.secs = htons(time(NULL) - dev->open_time);
	memcpy(bootp.chaddr, dev->hwaddr, 16);

	dprintf("-> bootp xid 0x%08x secs 0x%08x ",
	bootp.xid, ntohs(bootp.secs));

	return packet_send(dev, iov, 2);
	}

	/*
	* DESCRIPTION
	* bootp_ext119_decode() decodes Domain Search Option data.
	* The decoded string is separated with ' '.
	* For example, it is either "foo.bar.baz. bar.baz.", "foo.bar.", or "foo.".
	*
	* ARGUMENTS
	* const uint8_t *ext
	* ext is a pointer to a DHCP Domain Search Option data. ext does not
	* include a tag(code) octet and a length octet in DHCP options.
	* For example, if *ext is {3, 'f', 'o', 'o', 0}, this function returns
	* a pointer to a "foo." string.
	*
	* int16_t ext_size
	* ext_size is the memory size of *ext. For example,
	* if *ext is {3, 'f', 'o', 'o', 0}, ext_size must be 5.
	*
	* uint8_t *tmp
	* *tmp is a pointer to a temporary memory space for decoding.
	* The memory size must be equal to or more than ext_size.
	* 'memset(tmp, 0, sizeof(tmp));' is not required, but values in *tmp
	* are changed in decoding process.
	*
	* RETURN VALUE
	* if OK, a pointer to a decoded string malloc-ed
	* else , NULL
	*
	* SEE ALSO RFC3397
	*/
	static char bootp_ext119_decode(const void ext, int16_t ext_size, void *tmp)
	{
	uint8_t *u8ext;
	int_fast32_t i;
	int_fast32_t decoded_size;
	int_fast8_t currentdomain_is_singledot;

	/* only for validating ext /
	uint8_t *is_pointee;
	int_fast32_t is_pointee_size;

	/* only for structing a decoded string */
	char *decoded_str;
	int_fast32_t dst_i;

	if (ext == NULL \|\| ext_size <= 0 \|\| tmp == NULL)
	return NULL;

	u8ext = (uint8_t *)ext;
	is_pointee = tmp;
	memset(is_pointee, 0, (size_t)ext_size);
	is_pointee_size = 0;

	/*
	* validate the format of *ext and
	* calculate the memory size for a decoded string
	*/
	i = 0;
	decoded_size = 0;
	currentdomain_is_singledot = 1;
	while (1) {
	if (i >= ext_size)
	return NULL;

	if (u8ext[i] == 0) {
	/* Zero-ending */
	if (currentdomain_is_singledot)
	decoded_size++; /* for '.' */
	decoded_size++; /* for ' ' or '\0' */
	currentdomain_is_singledot = 1;
	i++;
	if (i == ext_size)
	break;
	is_pointee_size = i;
	} else if (u8ext[i] < 0x40) {
	/* Label(sub-domain string) */
	int j;

	/* loosely validate characters for domain names */
	if (i + u8ext[i] >= ext_size)
	return NULL;
	for (j = i + 1; j <= i + u8ext[i]; j++)
	if (!(u8ext[j] == '-' \|\|
	('0' <= u8ext[j] && u8ext[j] <= '9') \|\|
	('A' <= u8ext[j] && u8ext[j] <= 'Z') \|\|
	('a' <= u8ext[j] && u8ext[j] <= 'z')))
	return NULL;

	is_pointee[i] = 1;
	decoded_size += u8ext[i] + 1; /* for Label + '.' */
	currentdomain_is_singledot = 0;
	i += u8ext[i] + 1;
	} else if (u8ext[i] < 0xc0)
	return NULL;

	else {
	/* Compression-pointer (to a prior Label) */
	int_fast32_t p;

	if (i + 1 >= ext_size)
	return NULL;

	p = ((0x3f & u8ext[i]) << 8) + u8ext[i + 1];
	if (!(p < is_pointee_size && is_pointee[p]))
	return NULL;

	while (1) {
	/* u8ext[p] was validated */
	if (u8ext[p] == 0) {
	/* Zero-ending */
	decoded_size++;
	break;
	} else if (u8ext[p] < 0x40) {
	/* Label(sub-domain string) */
	decoded_size += u8ext[p] + 1;
	p += u8ext[p] + 1;
	} else {
	/* Compression-pointer */
	p = ((0x3f & u8ext[p]) << 8)
	+ u8ext[p + 1];
	}
	}

	currentdomain_is_singledot = 1;
	i += 2;
	if (i == ext_size)
	break;
	is_pointee_size = i;
	}
	}


	/*
	* construct a decoded string
	*/
	decoded_str = malloc(decoded_size);
	if (decoded_str == NULL)
	return NULL;

	i = 0;
	dst_i = 0;
	currentdomain_is_singledot = 1;
	while (1) {
	if (u8ext[i] == 0) {
	/* Zero-ending */
	if (currentdomain_is_singledot) {
	if (dst_i != 0)
	dst_i++;
	decoded_str[dst_i] = '.';
	}
	dst_i++;
	decoded_str[dst_i] = ' ';

	currentdomain_is_singledot = 1;
	i++;
	if (i == ext_size)
	break;
	} else if (u8ext[i] < 0x40) {
	/* Label(sub-domain string) */
	if (dst_i != 0)
	dst_i++;
	memcpy(&decoded_str[dst_i], &u8ext[i + 1],
	(size_t)u8ext[i]);
	dst_i += u8ext[i];
	decoded_str[dst_i] = '.';

	currentdomain_is_singledot = 0;
	i += u8ext[i] + 1;
	} else {
	/* Compression-pointer (to a prior Label) */
	int_fast32_t p;

	p = ((0x3f & u8ext[i]) << 8) + u8ext[i + 1];
	while (1) {
	if (u8ext[p] == 0) {
	/* Zero-ending */
	decoded_str[dst_i++] = '.';
	decoded_str[dst_i] = ' ';
	break;
	} else if (u8ext[p] < 0x40) {
	/* Label(sub-domain string) */
	dst_i++;
	memcpy(&decoded_str[dst_i],
	&u8ext[p + 1],
	(size_t)u8ext[p]);
	dst_i += u8ext[p];
	decoded_str[dst_i] = '.';

	p += u8ext[p] + 1;
	} else {
	/* Compression-pointer */
	p = ((0x3f & u8ext[p]) << 8)
	+ u8ext[p + 1];
	}
	}

	currentdomain_is_singledot = 1;
	i += 2;
	if (i == ext_size)
	break;
	}
	}
	decoded_str[dst_i] = '\0';
	#ifdef DEBUG
	if (dst_i + 1 != decoded_size) {
	dprintf("bug:%s():bottom: malloc(%ld), write(%ld)\n",
	__func__, (long)decoded_size, (long)(dst_i + 1));
	exit(1);
	}
	#endif
	return decoded_str;
	}

	/*
	* Parse a bootp reply packet
	*/
	int bootp_parse(struct netdev dev, struct bootp_hdr hdr,
	uint8_t *exts, int extlen)
	{
	uint8_t ext119_buf[BOOTP_EXTS_SIZE];
	int16_t ext119_len = 0;

	dev->bootp.gateway = hdr->giaddr;
	dev->ip_addr = hdr->yiaddr;
	dev->ip_server = hdr->siaddr;
	dev->ip_netmask = INADDR_ANY;
	dev->ip_broadcast = INADDR_ANY;
	dev->ip_gateway = hdr->giaddr;
	dev->ip_nameserver[0] = INADDR_ANY;
	dev->ip_nameserver[1] = INADDR_ANY;
	dev->hostname[0] = '\0';
	dev->nisdomainname[0] = '\0';
	dev->bootpath[0] = '\0';
	memcpy(&dev->filename, &hdr->boot_file, FNLEN);

	if (extlen >= 4 && exts[0] == 99 && exts[1] == 130 &&
	exts[2] == 83 && exts[3] == 99) {
	uint8_t *ext;

	for (ext = exts + 4; ext - exts < extlen;) {
	int len;
	uint8_t opt = *ext++;

	if (opt == 0)
	continue;
	else if (opt == 255)
	break;

	if (ext - exts >= extlen)
	break;
	len = *ext++;

	if (ext - exts + len > extlen)
	break;
	switch (opt) {
	case 1: /* subnet mask */
	if (len == 4)
	memcpy(&dev->ip_netmask, ext, 4);
	break;
	case 3: /* default gateway */
	if (len >= 4)
	memcpy(&dev->ip_gateway, ext, 4);
	break;
	case 6: /* DNS server */
	if (len >= 4)
	memcpy(&dev->ip_nameserver, ext,
	len >= 8 ? 8 : 4);
	break;
	case 12: /* host name */
	if (len > sizeof(dev->hostname) - 1)
	len = sizeof(dev->hostname) - 1;
	memcpy(&dev->hostname, ext, len);
	dev->hostname[len] = '\0';
	break;
	case 15: /* domain name */
	if (len > sizeof(dev->dnsdomainname) - 1)
	len = sizeof(dev->dnsdomainname) - 1;
	memcpy(&dev->dnsdomainname, ext, len);
	dev->dnsdomainname[len] = '\0';
	break;
	case 17: /* root path */
	if (len > sizeof(dev->bootpath) - 1)
	len = sizeof(dev->bootpath) - 1;
	memcpy(&dev->bootpath, ext, len);
	dev->bootpath[len] = '\0';
	break;
	case 26: /* interface MTU */
	if (len == 2)
	dev->mtu = (ext[0] << 8) + ext[1];
	break;
	case 28: /* broadcast addr */
	if (len == 4)
	memcpy(&dev->ip_broadcast, ext, 4);
	break;
	case 40: /* NIS domain name */
	if (len > sizeof(dev->nisdomainname) - 1)
	len = sizeof(dev->nisdomainname) - 1;
	memcpy(&dev->nisdomainname, ext, len);
	dev->nisdomainname[len] = '\0';
	break;
	case 54: /* server identifier */
	if (len == 4 && !dev->ip_server)
	memcpy(&dev->ip_server, ext, 4);
	break;
	case 119: /* Domain Search Option */
	if (ext119_len >= 0 &&
	ext119_len + len <= sizeof(ext119_buf)) {
	memcpy(ext119_buf + ext119_len,
	ext, len);
	ext119_len += len;
	} else
	ext119_len = -1;

	break;
	}

	ext += len;
	}
	}
	if (ext119_len > 0) {
	char *ret;
	uint8_t ext119_tmp[BOOTP_EXTS_SIZE];

	ret = bootp_ext119_decode(ext119_buf, ext119_len, ext119_tmp);
	if (ret != NULL) {
	if (dev->domainsearch != NULL)
	free(dev->domainsearch);
	dev->domainsearch = ret;
	}
	}

	/*
	* Got packet.
	*/
	return 1;
	}

	/*
	* Receive a bootp reply and parse packet
	* Returns:
	*-1 = Error in packet_recv, try again later
	* 0 = Unexpected packet, discarded
	* 1 = Correctly received and parsed packet
	*/
	int bootp_recv_reply(struct netdev *dev)
	{
	struct bootp_hdr bootp;
	uint8_t bootp_options[BOOTP_EXTS_SIZE];
	struct iovec iov[] = {
	/* [0] = ip + udp headers */
	[1] = {&bootp, sizeof(struct bootp_hdr)},
	[2] = {bootp_options, sizeof(bootp_options)}
	};
	int ret;

	ret = packet_recv(dev, iov, 3);
	if (ret <= 0)
	return ret;

	if (ret < sizeof(struct bootp_hdr) \|\|
	bootp.op != BOOTP_REPLY \|\| /* RFC951 7.5 */
	bootp.xid != dev->bootp.xid \|\|
	memcmp(bootp.chaddr, dev->hwaddr, 16))
	return 0;

	ret -= sizeof(struct bootp_hdr);

	return bootp_parse(dev, &bootp, bootp_options, ret);
	}

	/*
	* Initialise interface for bootp.
	*/
	int bootp_init_if(struct netdev *dev)
	{
	short flags;

	/*
	* Get the device flags
	*/
	if (netdev_getflags(dev, &flags))
	return -1;

	/*
	* We can't do DHCP nor BOOTP if this device
	* doesn't support broadcast.
	*/
	if (dev->mtu < 364 \|\| (flags & IFF_BROADCAST) == 0) {
	dev->caps &= ~(CAP_BOOTP \| CAP_DHCP);
	return 0;
	}

	/*
	* Get a random XID
	*/
	dev->bootp.xid = (uint32_t) lrand48();
	dev->open_time = time(NULL);

	return 0;
	}