net_ipv4_bootp.c

bootloader源代码

/*****************************************
 Copyright (c) 2001-2002 
 Sigma Designs, Inc. All Rights Reserved
 Proprietary and Confidential
 *****************************************/

/* This file is part of the boot loader */

/*
 * net_ipv4_bootp.c
 *
 * BOOTP/DHCP client
 *
 * RFCs related to BOOTP/DHCP
 *   RFC 951  "Bootstrap Protocol" (Obsoleted by 1395)
 *   RFC 1395 "BOOTP Vendor Information Extensions" (Obsoleted by 1497)
 *   RFC 1497 "BOOTP Vendor Information Extensions" (Obsoleted by 1533)
 *   RFC 1533 "DHCP Options and BOOTP Vendor Extensions" (Obsoleted by 2132)
 *   RFC 1534 "Interoperation Between DHCP and BOOTP"
 *   RFC 2132 "DHCP Options and BOOTP Vendor Extensions"
 */

#include "util.h"
#include "vsprintf.h"
#include "uart.h"
#include "timer.h"
#include "net.h"
#include "net_ipv4.h"
#include "bootconfig.h"

/*
 *	DHCP mechanism :
 *
 *	client				server
 *	--------------------------------
 *	DHCPDISCOVER =>						: client broadcasts looking for DHCP server
 *						<= DHCPOFFER	: server broadcasts to client with offer (IP address)
 *	DHCPREQUEST =>						: client broadcasts to server requesting IP which server offered
 *						<= DHCPACK		: server response with ACK
*/

// data structure for saving infomation from DHCP option
// used by dhcp_parse_option()
typedef struct dhcp_info {
	int message_type;
	uint32_t server_id;
	uint32_t lease_time;
	in_addr_t subnet;
	in_addr_t router;
	in_addr_t dns_server;
	in_addr_t broadcast;
	char domain[24];
} dhcp_info_t;

// 
// function prototypes
//

int dhcp_send_discover(unsigned int xid);
int dhcp_send_request(unsigned int xid, in_addr_t ipaddr, in_addr_t serverid);
void dhcp_parse_option(unsigned char *str, dhcp_info_t *info);

// parse bootp packet
int bootp_parsepacket(struct sk_buff *skb)
{
	skb->bootp = (struct bootphdr *) ((char *) skb->udp + sizeof(struct udphdr));
	skb->bootp->bp_secs = ntohs(skb->bootp->bp_secs);
	skb->bootp->bp_flags = ntohs(skb->bootp->bp_flags);
	skb->bootp->bp_ciaddr = ntohl(skb->bootp->bp_ciaddr);
	skb->bootp->bp_yiaddr = ntohl(skb->bootp->bp_yiaddr);
	skb->bootp->bp_siaddr = ntohl(skb->bootp->bp_siaddr);
	skb->bootp->bp_giaddr = ntohl(skb->bootp->bp_giaddr);

	return 0;
}

// bootp == 0 : DHCP protocol
// bootp != 0 : BOOP protocol
int ipv4_bootp(int bootp)
{
	static int s_last = 0;

	int retry;
	unsigned int xid;
	struct sk_buff *skb;
	dhcp_info_t info;

	// bootp header
	memcpy(&xid, &g_arptable[ARP_CLIENT].node[2], sizeof(xid));
	xid += htonl(s_last);
	s_last += 7;

	if (bootp)
		PrintUart("Looking for BOOTP server...\r\n", -1);
	else
		PrintUart("Discovering DHCP server...\r\n", -1);
	
	// BOOTP : 
	// DHCP : send DHCPDISCOVER message
	// wating for reply
	for (retry = 1; retry <= MAX_BOOTP_RETRIES; ++retry) {
		// flush RX buffer
		eth_receive(WAIT_NOTHING, 0);

		// send discover
		if (bootp)
			;
		else 
			dhcp_send_discover(xid);

		if ((skb = udp_receive(0, 0, IPPORT_BOOTP_CLIENT, TIMEOUT)) != NULL) {
			if (bootp_parsepacket(skb) == 0 && 
				skb->bootp->bp_op == BOOTP_REPLY && skb->bootp->bp_xid == xid)
				break;

			skb_free(skb);
			skb = NULL;
		}

		if (retry == MAX_BOOTP_RETRIES)
			PrintUart("Timeout. Connection failed.\r\n", -1);
		else
			PrintUart("Timeout. Retrying...\r\n", -1);
	}

	// BOOTP : 
	// DHCP : got DHCPOFFER
	if (skb) {
		if (bootp) {
			return 0;
		} else {
			memset(&info, 0, sizeof info);
			dhcp_parse_option(skb->bootp->bp_vend, &info);
			if (info.message_type != DHCPOFFER)
				return 1;
			skb_free(skb);

			PrintUart("Sending DHCP request...\r\n", -1);

			// Send request and wait for reply
			for (retry = 1; retry <= MAX_BOOTP_RETRIES; ++retry) {
				dhcp_send_request(xid, skb->bootp->bp_yiaddr, info.server_id);
				if ((skb = udp_receive(0, 0, IPPORT_BOOTP_CLIENT, TIMEOUT)) != NULL) {
					if (bootp_parsepacket(skb) == 0 && 
						skb->bootp->bp_op == BOOTP_REPLY && skb->bootp->bp_xid == xid)
						break;

					skb_free(skb);
					skb = NULL;
				}

				if (retry == MAX_BOOTP_RETRIES)
					PrintUart("Timeout. Connection failed.\r\n", -1);
				else
					PrintUart("Timeout. Retrying...\r\n", -1);
			}

			if (skb) {
				memset(&info, 0, sizeof info);
				dhcp_parse_option(skb->bootp->bp_vend, &info);
				if (info.message_type != DHCPACK)
					return 1;
				skb_free(skb);

				g_bootconfig.ipaddr = skb->bootp->bp_yiaddr;
				g_bootconfig.netmask = info.subnet;
				g_bootconfig.gateway = info.router;
				// g_bootconfig.server = skb->bootp->bp_siaddr;
				g_bootconfig.dns = info.dns_server;
				strcpy(g_bootconfig.domain, info.domain);
				net_arp_setup();

				PrintFormat("Got IP Address %s\n", ipaddr_to_str(skb->bootp->bp_yiaddr));

				return 0;
			}
		}
	}

	return 1;
}

/*
 * DHCP protocol definitions
 *
 * from RFC 2132
 */

#define DHCP_MAGIC				0x63825363

#define DHCP_PADDING			0x00	// 
#define DHCP_SUBNET				0x01	// [4] subnet mask
#define DHCP_TIME_OFFSET		0x02	// [4] client's subnet in section from UTC
#define DHCP_ROUTER				0x03	// [x4] router addresses
#define DHCP_TIME_SERVER		0x04	// [x4] time server addresses
#define DHCP_NAME_SERVER		0x05	// [x4] name server addresses
#define DHCP_DNS_SERVER			0x06	// [x4] DNS server addresses
#define DHCP_LOG_SERVER			0x07	// [x4] log server addresses
#define DHCP_COOKIE_SERVER		0x08	// [x4] cookie server addresses
#define DHCP_LPR_SERVER			0x09	// [x4] LPR (line printer server) addresses
#define DHCP_IMPRESS_SERVER		0x0a	// [x4] impress server addresses
#define DHCP_RESOURCE_SERVER	0x0b	// [x4] resource location server addresses
#define DHCP_HOST_NAME			0x0c	// [v] name of the client
#define DHCP_BOOT_SIZE			0x0d	// [2] boot file size
#define DHCP_MERIT_DUMP_FILE	0x0e	// [v] name of the file to which the client's core image should be dumped
#define DHCP_DOMAIN_NAME		0x0f	// [v] domain name
#define DHCP_SWAP_SERVER		0x10	// [4] IP address of the swap server
#define DHCP_ROOT_PATH			0x11	// [v] root disk's path name
#define DHCP_EXTENSION_PATH		0x12	// [v] file name retrievable via TFTP
#define DHCP_IP_FORWARDING		0x13	// [1] IP forwarding enable / disable
#define DHCP_SOURCE_ROUTING		0x14	// [1] Non-local source routing enable / disable
#define DHCP_POLICY_FILTER		0x15	// [x8] policy filter for non-local source routing
#define DHCP_MAX_DGRAM_REASM	0x16	// [2] maximum datagram reassembly size
#define DHCP_IP_TTL				0x17	// [1] IP Time-to-live
#define DHCP_PATH_MTU_TIMEOUT	0x18	// [4] Path MTU aging timeout
#define DHCP_PATH_MTU_PLATEAU	0x19	// [x2] Path MTU plateau table 
#define DHCP_MTU				0x1a	// [2] interface MTU 
#define DHCP_SUBNET_LOCAL		0x1b	// [1] All subnets are local option
#define DHCP_BROADCAST			0x1c	// [4] broadcast address
#define DHCP_MASK_DISCOVERY		0x1d	// [1] perform mask discovery
#define DHCP_MASK_SUPPLIER		0x1e	// [1] mask supplier
#define DHCP_ROUTER_DISCOVERY	0x1f	// [1] perform router discovery
#define DHCP_ROUTER_SOLICITATE	0x20	// [4] router solicitation address
#define DHCP_STATIC_ROUTE		0x21	// [x8] static route
#define DHCP_TRAILER_ENCAP		0x22	// [1] trailer encapsulation
#define DHCP_ARP_CACHE_TIMEOUT	0x23	// [4] ARP cache timeout ini seconds
#define DHCP_ETHERNET_ENCAP		0x24	// [1] ethernet encapsulation
#define DHCP_TCP_TTL			0x25	// [1] TCP default TTL 
#define DHCP_TCP_KEEPALIVE_INT	0x26	// [4] TCP keepalive interval
#define DHCP_TCP_KEEPALIVE_GAR	0x27	// [1] TCP keepalive garbage
#define DHCP_NIS_DOMAIN			0x28	// [v] NIS (Network information service) domain name
#define DHCP_NIS_SERVER			0x29	// [x4] NIS server addresses
#define DHCP_NTP_SERVER			0x2a	// [x4] NTP (Network time protocol) server addresses
#define DHCP_VENDOR_SPECIFIC	0x2b	// [v] vendor specific information
#define DHCP_NBNS_SERVER		0x2c	// [x4] NetBIOS over TCP/IP name server
#define DHCP_NBDD_SERVER		0x2d	// [x4] NetBIOS over TCP/IP datagram distribution server
#define DHCP_NB_NODETYPE		0x2e	// [1] NetBIOS over TCP/IP node type
#define DHCP_NB_SCOPE			0x2f	// [v] NetBIOS over TCP/IP scove
#define DHCP_XFONT_SERVER		0x30	// [x4] X Window font server
#define DHCP_XDISPLAY_MANAGER	0x31	// [x4] X Window system display manager
#define DHCP_REQUESTED_IP		0x32	// [4] requested IP address
#define DHCP_LEASE_TIME			0x33	// [4] IP address lease time
#define DHCPOPTION_OVERLOAD		0x34	// [1] option overload
#define DHCP_MESSAGE_TYPE		0x35	// [1] DHCP message type
#define DHCP_SERVER_ID			0x36	// [4] server identifier (DHCPOFFER, DHCPREQUEST)
#define DHCP_PARAM_REQUEST		0x37	// [v] parameter request list
#define DHCP_MESSAGE			0x38	// [v] error message
#define DHCP_MAX_SIZE			0x39	// [2] maximum DHCP message size
#define DHCP_T1					0x3a	// [4] renewal (T1) time value
#define DHCP_T2					0x3b	// [4] rebinding (T2) time value
#define DHCP_VENDOR_CLASS_ID	0x3c	// [v] vendor class identifier
#define DHCP_CLIENT_ID			0x3d	// [v] client identifier
#define DHCP_NISPLUS_DOMAIN		0x40	// [v] NIS+ domain name
#define DHCP_NISPLUS_SERVER		0x41	// [x4] NIS server 
#define DHCP_TFTP_SERVERNAME	0x42	// [v] TFTP server
#define DHCP_BOOTFILE			0x43	// [v] bootfile name
#define DHCP_MOBILE_IP_AGENT	0x44	// [x4] Mobile IP home agent
#define DHCP_SMTP_SERVER		0x45	// [x4] SMTP (Simple Mail Transfer Protocol) server
#define DHCP_POP3_SERVER		0x46	// [x4] POP3 (Post Office Protocol) server
#define DHCP_NNTP_SERVER		0x47	// [x4] NNTP (Network News Transport Protocol) server
#define DHCP_WWW_SERVER			0x48	// [x4] default WWW (World Wide Web) server
#define DHCP_FINGER_SERVER		0x49	// [x4] default finger server
#define DHCP_IRC_SERVER			0x4a	// [x4] default IRC (internet Relay Chat) server
#define DHCP_ST_SERVER			0x4b	// [x4] StreetTalk server
#define DHCP_ST_DA_SERVER		0x4c	// [x4] StreetTalk Directory Assistance server
#define DHCP_END				0xff	// 

/*
 * DHCP options definitions
 */

// option type
enum {
	DHCPOPT_INT8,						// 1 byte integer
	DHCPOPT_INT16,						// 2 bytes integer
	DHCPOPT_INT32,						// 4 bytes integer
	DHCPOPT_IPADDR,						// 4 bytes IP addresses
	DHCPOPT_IPADDR2,					// pair of IP addresses
	DHCPOPT_STR, 						// zero-terminated string (variant size)
	DHCPOPT_VARIABLE,					// non zero-terminated array of bytes 

	DHCPOPT_LIST = 0x100,				// list 
	DHCPOPT_TYPEMASK = 0xff,
};

static int s_option_len[] = {
	1, 2, 4, 4, 4, -1, -2 };

struct {
	int code;
	int flags;
} s_option_list[] = {
	{ DHCP_SUBNET,				DHCPOPT_IPADDR },
	{ DHCP_TIME_OFFSET,			DHCPOPT_INT32 },
	{ DHCP_ROUTER,				DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_TIME_SERVER,			DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_NAME_SERVER,			DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_DNS_SERVER,			DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_LOG_SERVER,			DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_COOKIE_SERVER,		DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_LPR_SERVER,			DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_IMPRESS_SERVER,		DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_RESOURCE_SERVER,		DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_HOST_NAME,			DHCPOPT_STR },
	{ DHCP_BOOT_SIZE,			DHCPOPT_INT16 },
	{ DHCP_MERIT_DUMP_FILE,		DHCPOPT_STR },
	{ DHCP_DOMAIN_NAME,			DHCPOPT_STR },
	{ DHCP_SWAP_SERVER,			DHCPOPT_IPADDR },
	{ DHCP_ROOT_PATH,			DHCPOPT_STR },
	{ DHCP_EXTENSION_PATH,		DHCPOPT_STR },
	{ DHCP_IP_FORWARDING,		DHCPOPT_INT8 },
	{ DHCP_SOURCE_ROUTING,		DHCPOPT_INT8 },
	{ DHCP_POLICY_FILTER,		DHCPOPT_IPADDR2 | DHCPOPT_LIST },
	{ DHCP_MAX_DGRAM_REASM,		DHCPOPT_INT16 },
	{ DHCP_IP_TTL,				DHCPOPT_INT8 },
	{ DHCP_PATH_MTU_TIMEOUT,	DHCPOPT_INT32 },
	{ DHCP_PATH_MTU_PLATEAU,	DHCPOPT_INT16 | DHCPOPT_LIST },
	{ DHCP_MTU,					DHCPOPT_INT16 },
	{ DHCP_SUBNET_LOCAL,		DHCPOPT_INT8 },
	{ DHCP_BROADCAST,			DHCPOPT_IPADDR },
	{ DHCP_MASK_DISCOVERY,		DHCPOPT_INT8 },
	{ DHCP_MASK_SUPPLIER,		DHCPOPT_INT8 },
	{ DHCP_ROUTER_DISCOVERY,	DHCPOPT_INT8 },
	{ DHCP_ROUTER_SOLICITATE,	DHCPOPT_IPADDR },
	{ DHCP_STATIC_ROUTE,		DHCPOPT_IPADDR2 | DHCPOPT_LIST },
	{ DHCP_TRAILER_ENCAP,		DHCPOPT_INT8 },
	{ DHCP_ARP_CACHE_TIMEOUT,	DHCPOPT_INT32 },
	{ DHCP_ETHERNET_ENCAP,		DHCPOPT_INT8 },
	{ DHCP_TCP_TTL,				DHCPOPT_INT8 },
	{ DHCP_TCP_KEEPALIVE_INT,	DHCPOPT_INT32 },
	{ DHCP_TCP_KEEPALIVE_GAR,	DHCPOPT_INT32 },
	{ DHCP_NIS_DOMAIN,			DHCPOPT_STR },
	{ DHCP_NIS_SERVER,			DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_NTP_SERVER,			DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_VENDOR_SPECIFIC,		DHCPOPT_STR },
	{ DHCP_NBNS_SERVER,			DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_NBDD_SERVER,			DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_NB_NODETYPE,			DHCPOPT_INT8 },
	{ DHCP_XFONT_SERVER,		DHCPOPT_IPADDR | DHCPOPT_LIST },
	{ DHCP_XDISPLAY_MANAGER,	DHCPOPT_IPADDR },
	{ DHCP_REQUESTED_IP,		DHCPOPT_IPADDR },