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nuttx/netutils/dhcpd/dhcpd.c
patacongo ac37ac75e0 errno now defined to be *get_errno_ptr() 
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@607 42af7a65-404d-4744-a932-0658087f49c3
2008-02-01 21:23:19 +00:00

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/****************************************************************************
* netutils/dhcpd/dhcpd.c
*
* Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#ifdef CONFIG_NETUTILS_DHCPD_HOST
# include <stdio.h>
typedef unsigned char uint8;
typedef unsigned short uint16;
typedef unsigned int uint32;
typedef unsigned char boolean;
# define HTONS(a) htons(a)
# define HTONL(a) htonl(a)
# define dbg(...) printf(__VA_ARGS__)
# define vdbg(...) printf(__VA_ARGS__)
# define TRUE (1)
# define FALSE (0)
# define ERROR (-1)
# define OK (0)
#else
# include <nuttx/config.h>
# include <debug.h>
# include <net/uip/dhcpd.h>
#endif
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
/****************************************************************************
* Private Data
****************************************************************************/
#define DHCP_SERVER_PORT 67
#define DHCP_CLIENT_PORT 68
/* Option codes understood in this file */
/* Code Data Description */
/* Length */
#define DHCP_OPTION_PAD 1 /* 1 Pad */
#define DHCP_OPTION_REQ_IPADDR 50 /* 4 Requested IP Address */
#define DHCP_OPTION_LEASE_TIME 51 /* 4 IP address lease time */
#define DHCP_OPTION_OVERLOAD 52 /* 1 Option overload */
#define DHCP_OPTION_MSG_TYPE 53 /* 1 DHCP message type */
#define DHCP_OPTION_SERVER_ID 54 /* 4 Server identifier */
#define DHCP_OPTION_END 255 /* 0 End */
/* Values for the dhcp msg 'op' field */
#define DHCP_REQUEST 1
#define DHCP_REPLY 2
/* DHCP message types understood in this file */
#define DHCPDISCOVER 1 /* Received from client only */
#define DHCPOFFER 2 /* Sent from server only */
#define DHCPREQUEST 3 /* Received from client only */
#define DHCPDECLINE 4 /* Received from client only */
#define DHCPACK 5 /* Sent from server only */
#define DHCPNAK 6 /* Sent from server only */
#define DHCPRELEASE 7 /* Received from client only */
#define DHCPINFORM 8 /* Not used */
/* The form of an option is:
* code - 1 byte
* length - 1 byte
* data - variable number of bytes
*/
#define DHCPD_OPTION_CODE 0
#define DHCPD_OPTION_LENGTH 1
#define DHCPD_OPTION_DATA 2
/* Size of options in DHCP message */
#define DHCPD_OPTIONS_SIZE 312
/* Values for htype and hlen field */
#define DHCP_HTYPE_ETHERNET 1
#define DHCP_HLEN_ETHERNET 6
/* Values for flags field */
#define BOOTP_BROADCAST 0x8000
/* Legal values for this option are:
*
* 1 the 'file' field is used to hold options
* 2 the 'sname' field is used to hold options
* 3 both fields are used to hold options
*/
#define DHCPD_OPTION_FIELD 0
#define DHCPD_FILE_FIELD 1
#define DHCPD_SNAME_FIELD 2
#ifndef CONFIG_NETUTILS_DHCPD_LEASETIME
# define CONFIG_NETUTILS_DHCPD_LEASETIME (60*60*24*10) /* 10 days */
# undef CONFIG_NETUTILS_DHCPD_MINLEASETIME
# undef CONFIG_NETUTILS_DHCPD_MAXLEASETIME
#endif
#ifndef CONFIG_NETUTILS_DHCPD_MINLEASETIME
# define CONFIG_NETUTILS_DHCPD_MINLEASETIME (60*60*24*1) /* 1 days */
#endif
#ifndef CONFIG_NETUTILS_DHCPD_MAXLEASETIME
# define CONFIG_NETUTILS_DHCPD_MAXLEASETIME (60*60*24*30) /* 30 days */
#endif
#ifndef CONFIG_NETUTILS_DHCPD_INTERFACE
# define CONFIG_NETUTILS_DHCPD_INTERFACE "eth0"
#endif
#ifndef CONFIG_NETUTILS_DHCPD_MAXLEASES
# define CONFIG_NETUTILS_DHCPD_MAXLEASES 16
#endif
#ifndef CONFIG_NETUTILS_DHCPD_STARTIP
# define CONFIG_NETUTILS_DHCPD_STARTIP (10<<24|0<<16|0<<16|2)
#endif
#undef CONFIG_NETUTILS_DHCP_OPTION_ENDIP
#define CONFIG_NETUTILS_DHCP_OPTION_ENDIP \
(CONFIG_NETUTILS_DHCPD_STARTIP + CONFIG_NETUTILS_DHCPD_MAXLEASES - 1)
#ifndef CONFIG_NETUTILS_DHCPD_OFFERTIME
# define CONFIG_NETUTILS_DHCPD_OFFERTIME (60*60) /* 1 hour */
#endif
#ifndef CONFIG_NETUTILS_DHCPD_DECLINETIME
# define CONFIG_NETUTILS_DHCPD_DECLINETIME (60*60) /* 1 hour */
#endif
#undef HAVE_LEASE_TIME
#if defined(CONFIG_NETUTILS_DHCPD_HOST) || !defined(CONFIG_DISABLE_POSIX_TIMERS)
# define HAVE_LEASE_TIME 1
#endif
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure describes one element in the lease table. There is one slot
* in the lease table for each assign-able IP address (hence, the IP address
* itself does not have to be in the table.
*/
struct lease_s
{
uint8 mac[DHCP_HLEN_ETHERNET]; /* MAC address (network order) -- could be larger! */
boolean allocated; /* true: IP address is allocated */
#ifdef HAVE_LEASE_TIME
time_t expiry; /* Lease expiration time (seconds past Epoch) */
#endif
};
struct dhcpmsg_s
{
uint8 op;
uint8 htype;
uint8 hlen;
uint8 hops;
uint8 xid[4];
uint16 secs;
uint16 flags;
uint8 ciaddr[4];
uint8 yiaddr[4];
uint8 siaddr[4];
uint8 giaddr[4];
uint8 chaddr[16];
#ifndef CONFIG_NET_DHCP_LIGHT
uint8 sname[64];
uint8 file[128];
#endif
uint8 options[312];
};
struct dhcpd_state_s
{
/* Server configuration */
in_addr_t ds_serverip; /* The server IP address */
/* Message buffers */
struct dhcpmsg_s ds_inpacket; /* Holds the incoming DHCP client message */
struct dhcpmsg_s ds_outpacket; /* Holds the outgoing DHCP server message */
/* Parsed options from the incoming DHCP client message */
uint8 ds_optmsgtype; /* Incoming DHCP message type */
in_addr_t ds_optreqip; /* Requested IP address (host order) */
in_addr_t ds_optserverip; /* Serverip IP address (host order) */
time_t ds_optleasetime; /* Requested lease time (host order) */
/* End option pointer for outgoing DHCP server message */
uint8 *ds_optend;
/* Leases */
struct lease_s ds_leases[CONFIG_NETUTILS_DHCPD_MAXLEASES];
};
/****************************************************************************
* Private Data
****************************************************************************/
static const uint8 g_magiccookie[4] = {99, 130, 83, 99};
static const uint8 g_anyipaddr[4] = {0, 0, 0, 0};
static struct dhcpd_state_s g_state;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: dhcpd_time
****************************************************************************/
#ifdef CONFIG_NETUTILS_DHCPD_HOST
# define dhcpd_time() time(0)
#elif defined(HAVE_LEASE_TIME)
static time_t dhcpd_time(void)
{
struct timespec time;
time_t ret = 0;
if (clock_gettime(CLOCK_REALTIME, &time) == OK)
{
ret = time.tv_sec;
}
return ret;
}
#else
# define dhcpd_time() (0)
#endif
/****************************************************************************
* Name: dhcpd_leaseexpired
****************************************************************************/
#ifdef HAVE_LEASE_TIME
static inline boolean dhcpd_leaseexpired(struct lease_s *lease)
{
if (lease->expiry < dhcpd_time())
{
return FALSE;
}
else
{
memset(lease, 0, sizeof(struct lease_s));
return TRUE;
}
}
#else
# define dhcpd_leaseexpired(lease) (FALSE)
#endif
/****************************************************************************
* Name: dhcpd_setlease
****************************************************************************/
struct lease_s *dhcpd_setlease(const uint8 *mac, in_addr_t ipaddr, time_t expiry)
{
int ndx = ntohl(ipaddr) - CONFIG_NETUTILS_DHCPD_STARTIP;
struct lease_s *ret = NULL;
if (ndx >= 0 && ndx < CONFIG_NETUTILS_DHCPD_MAXLEASES)
{
ret = &g_state.ds_leases[ndx];
memcpy(ret->mac, mac, DHCP_HLEN_ETHERNET);
ret->allocated = TRUE;
#ifdef HAVE_LEASE_TIME
ret->expiry = dhcpd_time() + expiry;
#endif
}
return ret;
}
/****************************************************************************
* Name: dhcp_leaseipaddr
****************************************************************************/
static inline in_addr_t dhcp_leaseipaddr( struct lease_s *lease)
{
return htonl((g_state.ds_leases - lease)/sizeof(struct lease_s) + CONFIG_NETUTILS_DHCPD_STARTIP);
}
/****************************************************************************
* Name: dhcpd_findbymac
****************************************************************************/
static struct lease_s *dhcpd_findbymac(const uint8 *mac)
{
int i;
for (i = 0; i < CONFIG_NETUTILS_DHCPD_MAXLEASES; i++)
{
if (memcmp(g_state.ds_leases[i].mac, mac, DHCP_HLEN_ETHERNET) == 0)
{
return &(g_state.ds_leases[i]);
}
}
return NULL;
}
/****************************************************************************
* Name: dhcpd_findbyipaddr
****************************************************************************/
static struct lease_s *dhcpd_findbyipaddr(in_addr_t ipaddr)
{
if (ipaddr >= CONFIG_NETUTILS_DHCPD_STARTIP &&
ipaddr <= CONFIG_NETUTILS_DHCP_OPTION_ENDIP)
{
struct lease_s *lease = &g_state.ds_leases[ipaddr - CONFIG_NETUTILS_DHCPD_STARTIP];
if (lease->allocated > 0)
{
return lease;
}
}
return NULL;
}
/****************************************************************************
* Name: dhcpd_allocipaddr
****************************************************************************/
in_addr_t dhcpd_allocipaddr(void)
{
struct lease_s *lease = NULL;
in_addr_t ipaddr;
ipaddr = CONFIG_NETUTILS_DHCPD_STARTIP;
for (; ipaddr <= CONFIG_NETUTILS_DHCP_OPTION_ENDIP; ipaddr++)
{
if ((ipaddr & 0xff) == 0 || (ipaddr & 0xff) == 0xff)
{
continue;
}
lease = dhcpd_findbyipaddr(ipaddr);
if ((!lease || dhcpd_leaseexpired(lease)))
{
#warning "FIXME: Should check if anything responds to an ARP request or ping"
#warning " to verify that there is no other user of this IP address"
memset(g_state.ds_leases[ipaddr - CONFIG_NETUTILS_DHCPD_STARTIP].mac, 0, DHCP_HLEN_ETHERNET);
g_state.ds_leases[ipaddr - CONFIG_NETUTILS_DHCPD_STARTIP].allocated = TRUE;
#ifdef HAVE_LEASE_TIME
g_state.ds_leases[ipaddr - CONFIG_NETUTILS_DHCPD_STARTIP].expiry = dhcpd_time() + CONFIG_NETUTILS_DHCPD_OFFERTIME;
#endif
return ntohl(ipaddr);
}
}
return 0;
}
/****************************************************************************
* Name: dhcpd_parseoptions
****************************************************************************/
static inline boolean dhcpd_parseoptions(void)
{
uint32 tmp;
uint8 *ptr;
uint8 overloaded;
uint8 currfield;
int optlen;
int remaining;
/* Verify that the option field starts with a valid magic number */
ptr = g_state.ds_inpacket.options;
if (memcmp(ptr, g_magiccookie, 4) != 0)
{
/* Bad magic number... skip g_state.ds_outpacket */
dbg("Bad magic: %d,%d,%d,%d\n", ptr[0], ptr[1], ptr[2], ptr[3]);
return FALSE;
}
/* Set up to parse the options */
ptr += 4;
remaining = DHCPD_OPTIONS_SIZE - 4;
overloaded = DHCPD_OPTION_FIELD;
currfield = DHCPD_OPTION_FIELD;
/* Set all options to the default value */
g_state.ds_optmsgtype = 0; /* Incoming DHCP message type */
g_state.ds_optreqip = 0; /* Requested IP address (host order) */
g_state.ds_optserverip = 0; /* Serverip IP address (host order) */
g_state.ds_optleasetime = 0; /* Requested lease time (host order) */
g_state.ds_optend = NULL;
do
{
/* The form of an option is:
* code - 1 byte
* length - 1 byte
* data - variable number of bytes
*/
switch (ptr[DHCPD_OPTION_CODE])
{
/* Skip over any padding bytes */
case DHCP_OPTION_PAD:
optlen = 1;
break;
/* the Overload option is used to indicate that the DHCP 'sname' or 'file'
* fields are being overloaded by using them to carry DHCP options. A DHCP
* server inserts this option if the returned parameters will exceed the
* usual space allotted for options.
*
* If this option is present, the client interprets the specified additional
* fields after it concludes interpretation of the standard option fields.
*
* Legal values for this option are:
*
* 1 the 'file' field is used to hold options
* 2 the 'sname' field is used to hold options
* 3 both fields are used to hold options
*/
#ifndef CONFIG_NET_DHCP_LIGHT
case DHCP_OPTION_OVERLOAD:
optlen = ptr[DHCPD_OPTION_LENGTH] + 2;
if (optlen >= 1 && optlen < remaining)
{
overloaded = ptr[DHCPD_OPTION_DATA];
}
break;
#endif
case DHCP_OPTION_END:
#ifndef CONFIG_NET_DHCP_LIGHT
if (currfield == DHCPD_OPTION_FIELD &&
(overloaded & DHCPD_FILE_FIELD) != 0)
{
ptr = g_state.ds_inpacket.file;
remaining = sizeof(g_state.ds_inpacket.file);
currfield = DHCPD_FILE_FIELD;
}
else if (currfield == DHCPD_FILE_FIELD &&
(overloaded & DHCPD_SNAME_FIELD) != 0)
{
ptr = g_state.ds_inpacket.sname;
remaining = sizeof(g_state.ds_inpacket.sname);
currfield = DHCPD_SNAME_FIELD;
}
else
{
return TRUE;
}
break;
#else
return TRUE;
#endif
case DHCP_OPTION_REQ_IPADDR: /* Requested IP Address */
optlen = ptr[DHCPD_OPTION_LENGTH] + 2;
if (optlen >= 4 && optlen < remaining)
{
memcpy(&tmp, &ptr[DHCPD_OPTION_DATA], 4);
g_state.ds_optreqip = (in_addr_t)ntohl(tmp);
}
break;
case DHCP_OPTION_LEASE_TIME: /* IP address lease time */
optlen = ptr[DHCPD_OPTION_LENGTH] + 2;
if (optlen >= 4 && optlen < remaining)
{
memcpy(&tmp, &ptr[DHCPD_OPTION_DATA], 4);
g_state.ds_optleasetime = (time_t)ntohl(tmp);
}
break;
case DHCP_OPTION_MSG_TYPE: /* DHCP message type */
optlen = ptr[DHCPD_OPTION_LENGTH] + 2;
if (optlen >= 1 && optlen < remaining)
{
g_state.ds_optmsgtype = ptr[DHCPD_OPTION_DATA];
}
break;
case DHCP_OPTION_SERVER_ID: /* Server identifier */
optlen = ptr[DHCPD_OPTION_LENGTH] + 2;
if (optlen >= 4 && optlen < remaining)
{
memcpy(&tmp, &ptr[DHCPD_OPTION_DATA], 4);
g_state.ds_optserverip = (in_addr_t)ntohl(tmp);
}
break;
default:
/* Skip over unsupported options */
optlen = ptr[DHCPD_OPTION_LENGTH] + 2;
break;
}
/* Advance to the next option */
ptr += optlen;
remaining -= optlen;
}
while (remaining > 0);
return FALSE;
}
/****************************************************************************
* Name: dhcpd_verifyreqip
****************************************************************************/
static inline boolean dhcpd_verifyreqip(void)
{
struct lease_s *lease;
/* Verify that the requested IP address is within the supported lease range */
if (g_state.ds_optreqip > 0 &&
g_state.ds_optreqip >= CONFIG_NETUTILS_DHCPD_STARTIP &&
g_state.ds_optreqip <= CONFIG_NETUTILS_DHCP_OPTION_ENDIP)
{
/* And verify that the lease has not already been taken or offered
* (unless the lease/offer is expired, then the address is free game).
*/
lease = dhcpd_findbyipaddr(g_state.ds_optreqip);
if (!lease || dhcpd_leaseexpired(lease))
{
return TRUE;
}
}
return FALSE;
}
/****************************************************************************
* Name: dhcpd_verifyreqleasetime
****************************************************************************/
static inline boolean dhcpd_verifyreqleasetime(uint32 *leasetime)
{
uint32 tmp = g_state.ds_optleasetime;
/* Did the client request a specific lease time? */
if (tmp != 0)
{
/* Yes.. Verify that the requested lease time is within a valid range */
if (tmp > CONFIG_NETUTILS_DHCPD_MAXLEASETIME)
{
tmp = CONFIG_NETUTILS_DHCPD_MAXLEASETIME;
}
else if (tmp < CONFIG_NETUTILS_DHCPD_MINLEASETIME)
{
tmp = CONFIG_NETUTILS_DHCPD_MINLEASETIME;
}
/* Return the clipped lease time */
*leasetime = tmp;
return TRUE;
}
return FALSE;
}
/****************************************************************************
* Name: dhcpd_addoption
****************************************************************************/
static int dhcpd_addoption(uint8 *option)
{
int offset;
int len = 4;
if (g_state.ds_optend)
{
offset = g_state.ds_outpacket.options - g_state.ds_optend;
len = option[DHCPD_OPTION_LENGTH] + 2;
/* Check if the option will fit into the options array */
if (offset + len + 1 < DHCPD_OPTIONS_SIZE)
{
/* Copy the option into the option array */
memcpy(g_state.ds_optend, option, len);
g_state.ds_optend += len;
*g_state.ds_optend = DHCP_OPTION_END;
}
}
return len;
}
/****************************************************************************
* Name: dhcpd_addoption8
****************************************************************************/
static int dhcpd_addoption8(uint8 code, uint8 value)
{
uint8 option[3];
/* Construct the option sequence */
option[DHCPD_OPTION_CODE] = code;
option[DHCPD_OPTION_LENGTH] = 1;
option[DHCPD_OPTION_DATA] = value;
/* Add the option sequence to the response */
return dhcpd_addoption(option);
}
/****************************************************************************
* Name: dhcpd_addoption32
****************************************************************************/
static int dhcpd_addoption32(uint8 code, uint32 value)
{
uint8 option[6];
/* Construct the option sequence */
option[DHCPD_OPTION_CODE] = code;
option[DHCPD_OPTION_LENGTH] = 4;
memcpy(&option[DHCPD_OPTION_DATA], &value, 4);
/* Add the option sequence to the response */
return dhcpd_addoption(option);
}
/****************************************************************************
* Name: dhcpd_soclet
****************************************************************************/
static inline int dhcpd_socket(void)
{
int sockfd;
#if defined(HAVE_SO_REUSEADDR) || defined(HAVE_SO_BROADCAST)
int optval;
int ret;
#endif
/* Create a socket to listen for requests from DHCP clients */
sockfd = socket(PF_INET, SOCK_DGRAM, 0);
if (sockfd < 0)
{
dbg("socket failed: %d\n", errno);
return ERROR;
}
/* Configure the socket */
#ifdef HAVE_SO_REUSEADDR
optval = 1;
ret = setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (void*)&optval, sizeof(int));
if (ret < 0)
{
dbg("setsockopt SO_REUSEADDR failed: %d\n", errno);
close(sockfd);
return ERROR;
}
#endif
#ifdef HAVE_SO_BROADCAST
optval = 1;
ret = setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, (void*)&optval, sizeof(int));
if (ret < 0)
{
dbg("setsockopt SO_BROADCAST failed: %d\n", errno);
close(sockfd);
return ERROR;
}
#endif
return sockfd;
}
/****************************************************************************
* Name: dhcpd_openresponder
****************************************************************************/
static inline int dhcpd_openresponder(void)
{
struct sockaddr_in addr;
int sockfd;
int ret;
/* Create a socket to listen for requests from DHCP clients */
sockfd = dhcpd_socket();
if (sockfd < 0)
{
dbg("socket failed: %d\n", errno);
return ERROR;
}
/* Bind the socket to a local port. We have to use INADDRY_ANY to
* receive broadcast messages.
*/
addr.sin_family = AF_INET;
addr.sin_port = htons(DHCP_SERVER_PORT);
addr.sin_addr.s_addr = g_state.ds_serverip;
ret = bind(sockfd, (struct sockaddr *)&addr, sizeof(struct sockaddr_in));
if (ret < 0)
{
dbg("bind failed: %d\n", errno);
close(sockfd);
return ERROR;
}
return sockfd;
}
/****************************************************************************
* Name: dhcpd_initpacket
****************************************************************************/
static void dhcpd_initpacket(uint8 mtype)
{
/* Set up the generic parts of the DHCP server message */
memset(&g_state.ds_outpacket, 0, sizeof(struct dhcpmsg_s));
g_state.ds_outpacket.op = DHCP_REPLY;
g_state.ds_outpacket.htype = g_state.ds_inpacket.htype;
g_state.ds_outpacket.hlen = g_state.ds_inpacket.hlen;
memcpy(&g_state.ds_outpacket.xid, &g_state.ds_inpacket.xid, 4);
memcpy(g_state.ds_outpacket.chaddr, g_state.ds_inpacket.chaddr, 16);
if (g_state.ds_outpacket.giaddr)
{
g_state.ds_outpacket.flags = g_state.ds_inpacket.flags;
}
else
{
g_state.ds_outpacket.flags = 0;
}
memset(g_state.ds_outpacket.giaddr, 0, 4);
/* Add the generic options */
memcpy(g_state.ds_outpacket.options, g_magiccookie, 4);
g_state.ds_optend = &g_state.ds_outpacket.options[4];
*g_state.ds_optend = DHCP_OPTION_END;
dhcpd_addoption8(DHCP_OPTION_MSG_TYPE, mtype);
dhcpd_addoption32(DHCP_OPTION_SERVER_ID, g_state.ds_serverip);
}
/****************************************************************************
* Name: dhcpd_sendpacket
****************************************************************************/
static int dhcpd_sendpacket(int bbroadcast)
{
struct sockaddr_in addr;
in_addr_t ipaddr;
int sockfd;
int len;
int ret = ERROR;
/* Determine which address to respond to (or if we need to broadcast the response) */
if (bbroadcast)
{
ipaddr = INADDR_BROADCAST;
}
else if (memcmp(g_state.ds_outpacket.ciaddr, g_anyipaddr, 4) != 0)
{
memcpy(&ipaddr, g_state.ds_outpacket.ciaddr, 4);
}
else if (g_state.ds_outpacket.flags & HTONS(BOOTP_BROADCAST))
{
ipaddr = INADDR_BROADCAST;
}
else
{
memcpy(&ipaddr, g_state.ds_outpacket.yiaddr, 4);
}
/* Create a socket to respond to send the packet to the client. We
* cannot re-use the listener socket because it is not bound correctly
*/
sockfd = dhcpd_openresponder();
if (sockfd >= 0)
{
/* Then send the reponse to the DHCP client port at that address */
memset(&addr, 0, sizeof(struct sockaddr_in));
addr.sin_family = AF_INET;
addr.sin_port = HTONS(DHCP_CLIENT_PORT);
addr.sin_addr.s_addr = ipaddr;
/* Send the minimum sized packet that includes the END option */
len = (g_state.ds_optend - (uint8*)&g_state.ds_outpacket) + 1;
ret = sendto(sockfd, &g_state.ds_outpacket, len, 0,
(struct sockaddr *)&addr, sizeof(struct sockaddr_in));
close(sockfd);
}
return ret;
}
/****************************************************************************
* Name: dhcpd_sendoffer
****************************************************************************/
static inline int dhcpd_sendoffer(in_addr_t ipaddr, uint32 leasetime)
{
/* Initialize the outgoing packet */
dhcpd_initpacket(DHCPOFFER);
/* Add the address offered to the client */
memcpy(g_state.ds_outpacket.yiaddr, &ipaddr, 4);
/* Add the leasetime to the response options */
dhcpd_addoption32(DHCP_OPTION_LEASE_TIME, htonl(leasetime));
/* Send the offer response */
return dhcpd_sendpacket(FALSE);
}
/****************************************************************************
* Name: dhcpd_sendnak
****************************************************************************/
static int dhcpd_sendnak(void)
{
/* Initialize and send the NAK response */
dhcpd_initpacket(DHCPNAK);
memcpy(g_state.ds_outpacket.ciaddr, g_state.ds_inpacket.ciaddr, 4);
return dhcpd_sendpacket(TRUE);
}
/****************************************************************************
* Name: dhcpd_sendack
****************************************************************************/
int dhcpd_sendack(in_addr_t ipaddr)
{
uint32 leasetime = CONFIG_NETUTILS_DHCPD_LEASETIME;
/* Initialize the ACK response */
dhcpd_initpacket(DHCPACK);
memcpy(g_state.ds_outpacket.ciaddr, g_state.ds_inpacket.ciaddr, 4);
/* Add the IP address assigned to the client */
memcpy(g_state.ds_outpacket.yiaddr, &ipaddr, 4);
/* Did the client request a specific lease time? */
(void)dhcpd_verifyreqleasetime(&leasetime);
/* Add the lease time to the response */
dhcpd_addoption32(DHCP_OPTION_LEASE_TIME, htonl(leasetime));
if (dhcpd_sendpacket(FALSE) < 0)
{
return ERROR;
}
dhcpd_setlease(g_state.ds_inpacket.chaddr, ipaddr, leasetime);
return OK;
}
/****************************************************************************
* Name: dhcpd_discover
****************************************************************************/
static inline int dhcpd_discover(void)
{
struct lease_s *lease;
in_addr_t ipaddr;
uint32 leasetime = CONFIG_NETUTILS_DHCPD_LEASETIME;
/* Check if the client is aleady in the lease table */
lease = dhcpd_findbymac(g_state.ds_inpacket.chaddr);
if (lease)
{
/* Yes... get the remaining time on the lease */
#ifdef HAVE_LEASE_TIME
if (!dhcpd_leaseexpired(lease))
{
leasetime = lease->expiry - dhcpd_time();
if (leasetime < CONFIG_NETUTILS_DHCPD_MINLEASETIME)
{
leasetime = CONFIG_NETUTILS_DHCPD_MINLEASETIME;
}
}
#endif
/* Get the IP address associated with the lease */
ipaddr = dhcp_leaseipaddr(lease);
}
/* Check if the client has requested a specific IP address */
else if (dhcpd_verifyreqip())
{
/* Use the requested IP address */
ipaddr = g_state.ds_optreqip;
}
else
{
/* No... allocate a new IP address */
ipaddr = dhcpd_allocipaddr();
}
/* Did we get any IP address? */
if (!ipaddr)
{
/* Nope... return failure */
dbg("Failed to get IP address\n");
return ERROR;
}
/* Reserve the leased IP for a shorter time for the offer */
if (!dhcpd_setlease(g_state.ds_inpacket.chaddr, ipaddr, CONFIG_NETUTILS_DHCPD_OFFERTIME))
{
dbg("Failed to set lease\n");
return ERROR;
}
/* Check if the client has requested a specific lease time */
(void)dhcpd_verifyreqleasetime(&leasetime);
/* Send the offer response */
return dhcpd_sendoffer(ipaddr, leasetime);
}
/****************************************************************************
* Name: dhcpd_request
****************************************************************************/
static inline int dhcpd_request(void)
{
struct lease_s *lease;
in_addr_t ipaddr;
uint8 response = 0;
/* Check if this client already holds a lease. This can happen when the client (1)
* the IP is reserved for the client from a previous offer, or (2) the client is
* re-initializing or rebooting while the lease is still valid.
*/
lease = dhcpd_findbymac(g_state.ds_inpacket.chaddr);
if (lease)
{
/* Yes.. the client already holds a lease. Verify that the request is consistent
* with the existing lease.
*/
ipaddr = dhcp_leaseipaddr(lease);
if (g_state.ds_optserverip)
{
/* ACK if the serverip is correct and the requested IP address is the one
* already offered to the client.
*/
if (g_state.ds_optserverip == ntohl(g_state.ds_serverip) &&
(g_state.ds_optreqip != 0 || g_state.ds_optreqip == ipaddr))
{
response = DHCPACK;
}
else
{
response = DHCPNAK;
}
}
/* We have the lease and no server IP was requested. Was as specific IP address
* requested?
*/
else if (g_state.ds_optreqip)
{
/* Yes..ACK if the requested IP address is the one already leased */
if (ipaddr == g_state.ds_optreqip)
{
response = DHCPACK;
}
else
{
response = DHCPNAK;
}
}
/* The client has specified neither a server IP nor requested IP address */
else
{
/* ACK if the IP used by the client is the one already assigned to it */
if (memcmp(&ipaddr, g_state.ds_inpacket.ciaddr, 4) == 0)
{
response = DHCPACK;
}
else
{
response = DHCPNAK;
}
}
}
/* The client does not hold a lease (referenced by its MAC address) and is
* requesting a specific IP address that was, apparently, never offered to
* to the client. Perform some sanity checks before sending the NAK.
*/
else if (g_state.ds_optreqip && !g_state.ds_optserverip)
{
/* Is this IP address already assigned? */
lease = dhcpd_findbyipaddr(g_state.ds_optreqip);
if (lease)
{
/* Yes.. Send NAK unless the lease has expired */
if (!dhcpd_leaseexpired(lease))
{
response = DHCPNAK;
}
}
/* No.. is the requested IP address in range? NAK if not */
else if (g_state.ds_optreqip < CONFIG_NETUTILS_DHCPD_STARTIP ||
g_state.ds_optreqip > CONFIG_NETUTILS_DHCP_OPTION_ENDIP)
{
response = DHCPNAK;
}
}
/* Finally, either (1) send the ACK, (2) send a NAK, or (3) remain silent
* based on the checks above.
*/
if (response == DHCPACK)
{
dhcpd_sendack(ipaddr);
}
else if (response == DHCPNAK)
{
dhcpd_sendnak();
}
return OK;
}
/****************************************************************************
* Name: dhcpd_decline
****************************************************************************/
static inline int dhcpd_decline(void)
{
struct lease_s *lease;
/* Find the lease associated with this hardware address */
lease = dhcpd_findbymac(g_state.ds_inpacket.chaddr);
if (lease)
{
/* Disassociate the IP from the MAC, but prevent re-used of this
* address for a period of time.
*/
memset(lease->mac, 0, DHCP_HLEN_ETHERNET);
#ifdef HAVE_LEASE_TIME
lease->expiry = dhcpd_time() + CONFIG_NETUTILS_DHCPD_DECLINETIME;
#endif
}
return OK;
}
static inline int dhcpd_release(void)
{
struct lease_s *lease;
/* Find the lease associated with this hardware address */
lease = dhcpd_findbymac(g_state.ds_inpacket.chaddr);
if (lease)
{
/* Release the IP address now */
memset(lease, 0, sizeof(struct lease_s));
}
return OK;
}
/****************************************************************************
* Name: dhcpd_openlistener
****************************************************************************/
static inline int dhcpd_openlistener(void)
{
struct sockaddr_in addr;
struct ifreq req;
int sockfd;
int ret;
/* Create a socket to listen for requests from DHCP clients */
sockfd = dhcpd_socket();
if (sockfd < 0)
{
dbg("socket failed: %d\n", errno);
return ERROR;
}
/* Get the IP address of the selected device */
strncpy(req.ifr_name, CONFIG_NETUTILS_DHCPD_INTERFACE, IFNAMSIZ);
ret = ioctl(sockfd, SIOCGIFADDR, (unsigned long)&req);
if (ret < 0)
{
dbg("setsockopt SIOCGIFADDR failed: %d\n", errno);
close(sockfd);
return ERROR;
}
g_state.ds_serverip = ((struct sockaddr_in*)&req.ifr_addr)->sin_addr.s_addr;
vdbg("serverip: %08x\n", ntohl(g_state.ds_serverip));
/* Bind the socket to a local port. We have to bind to INADDRY_ANY to
* receive broadcast messages.
*/
addr.sin_family = AF_INET;
addr.sin_port = htons(DHCP_SERVER_PORT);
addr.sin_addr.s_addr = INADDR_ANY;
ret = bind(sockfd, (struct sockaddr *)&addr, sizeof(struct sockaddr_in));
if (ret < 0)
{
dbg("bind failed: %d\n", errno);
close(sockfd);
return ERROR;
}
return sockfd;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: dhcpd_run
****************************************************************************/
int dhcpd_run(void)
{
int sockfd;
int nbytes;
vdbg("Started\n");
/* Initialize everything to zero */
memset(&g_state, 0, sizeof(struct dhcpd_state_s));
/* Now loop indefinitely, reading packets from the DHCP server socket */
sockfd = -1;
for (;;)
{
/* Create a socket to listen for requests from DHCP clients */
if (sockfd < 0)
{
sockfd = dhcpd_openlistener();
if (sockfd < 0)
{
dbg("Failed to create socket\n");
break;
}
}
/* Read the next g_state.ds_outpacket */
nbytes = recv(sockfd, &g_state.ds_inpacket, sizeof(struct dhcpmsg_s), 0);
if (nbytes < 0)
{
/* On errors (other EINTR), close the socket and try again */
dbg("recv failed: %d\n", errno);
if (errno != EINTR)
{
close(sockfd);
sockfd = -1;
}
continue;
}
/* Parse the incoming message options */
if (!dhcpd_parseoptions())
{
/* Failed to parse the message options */
dbg("No msg type\n");
continue;
}
#ifdef CONFIG_NETUTILS_DHCPD_HOST
/* Get the poor little uC a change to get its recvfrom in place */
usleep(500*1000);
#endif
/* Now process the incoming DHCP message by its message type */
switch (g_state.ds_optmsgtype)
{
case DHCPDISCOVER:
vdbg("DHCPDISCOVER\n");
dhcpd_discover();
break;
case DHCPREQUEST:
vdbg("DHCPREQUEST\n");
dhcpd_request();
break;
case DHCPDECLINE:
vdbg("DHCPDECLINE\n");
dhcpd_decline();
break;
case DHCPRELEASE:
vdbg("DHCPRELEASE\n");
dhcpd_release();
break;
case DHCPINFORM: /* Not supported */
default:
dbg("Unsupported message type: %d\n", g_state.ds_optmsgtype);
break;
}
}
return OK;
}
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