DHCP client and server, from Ashwini Sharma.

1 files changed, 1247 insertions, 0 deletions

diff --git a/toys/pending/dhcpd.c b/toys/pending/dhcpd.c
new file mode 100644
index 00000000..18f4f25e
--- /dev/null
+++ b/toys/pending/dhcpd.c
@@ -0,0 +1,1247 @@
+/* dhcpd.c - DHCP server for dynamic network configuration.
+ *
+ * Copyright 2013 Madhur Verma <mad.flexi@gmail.com>
+ * Copyright 2013 Kyungwan Han <asura321@gamil.com>
+ *
+ * No Standard
+USE_DHCPD(NEWTOY(dhcpd, ">1P#<0>65535=67fS", TOYFLAG_SBIN|TOYFLAG_ROOTONLY))
+
+config DHCPD
+  bool "dhcpd"
+  default n
+  help
+   Usage: dhcpd [-fS] [-P N] [CONFFILE]
+
+    -f    Run in foreground
+    -S    Log to syslog too
+    -P N  Use port N (default 67)
+
+config DEBUG_DHCP
+  bool "debugging messeges ON/OFF"
+  default n
+  depends on DHCPD
+*/
+
+#define FOR_dhcpd
+
+#include "toys.h"
+#include "toynet.h"
+#include <linux/sockios.h> 
+#include <linux/if_ether.h>
+
+// Todo: headers not in posix
+#include <netinet/ip.h>
+#include <netinet/udp.h>
+#include <netpacket/packet.h>
+
+#if CFG_DEBUG_DHCP==1
+# define dbg(fmt, arg...)   printf(fmt, ##arg)
+#else
+# define dbg(fmt, arg...)
+#endif
+
+#define flag_get(f,v,d)     ((toys.optflags & (f)) ? (v) : (d))
+#define flag_chk(f)         ((toys.optflags & (f)) ? 1 : 0)
+
+#define LOG_SILENT          0x0
+#define LOG_CONSOLE         0x1
+#define LOG_SYSTEM          0x2
+
+#define DHCP_MAGIC          0x63825363
+
+#define DHCPDISCOVER        1
+#define DHCPOFFER           2
+#define DHCPREQUEST         3
+#define DHCPDECLINE         4
+#define DHCPACK             5
+#define DHCPNAK             6
+#define DHCPRELEASE         7
+#define DHCPINFORM          8
+
+#define DHCP_NUM8           (1<<8)
+#define DHCP_NUM16          (1<<9)
+#define DHCP_NUM32          DHCP_NUM16 | DHCP_NUM8
+#define DHCP_STRING         (1<<10)
+#define DHCP_STRLST         (1<<11)
+#define DHCP_IP             (1<<12)
+#define DHCP_IPLIST         (1<<13)
+#define DHCP_IPPLST         (1<<14)
+#define DHCP_STCRTS         (1<<15)
+
+// DHCP option codes (partial list). See RFC 2132 and
+#define DHCP_OPT_PADDING                          0x00
+#define DHCP_OPT_HOST_NAME          DHCP_STRING | 0x0c // either client informs server or server gives name to client
+#define DHCP_OPT_REQUESTED_IP       DHCP_IP     | 0x32 // sent by client if specific IP is wanted
+#define DHCP_OPT_LEASE_TIME         DHCP_NUM32  | 0x33
+#define DHCP_OPT_OPTION_OVERLOAD                  0x34
+#define DHCP_OPT_MESSAGE_TYPE       DHCP_NUM8   | 0x35
+#define DHCP_OPT_SERVER_ID          DHCP_IP     | 0x36 // by default server's IP
+#define DHCP_OPT_PARAM_REQ          DHCP_STRING | 0x37 // list of options client wants
+#define DHCP_OPT_END                              0xff
+
+GLOBALS(
+    long port;
+);
+
+typedef struct __attribute__((packed)) dhcp_msg_s {
+  uint8_t op;
+  uint8_t htype;
+  uint8_t hlen;
+  uint8_t hops;
+  uint32_t xid;
+  uint16_t secs;
+  uint16_t flags;
+  uint32_t ciaddr;
+  uint32_t yiaddr;
+  uint32_t nsiaddr;
+  uint32_t ngiaddr;
+  uint8_t chaddr[16];
+  uint8_t sname[64];
+  uint8_t file[128];
+  uint32_t cookie;
+  uint8_t options[308];
+} dhcp_msg_t;
+
+typedef struct __attribute__((packed)) dhcp_raw_s {
+  struct iphdr iph;
+  struct udphdr udph;
+  dhcp_msg_t dhcp;
+} dhcp_raw_t;
+
+typedef struct static_lease_s {
+  struct static_lease_s *next;
+  uint32_t nip;
+  int mac[6];
+} static_lease;
+
+typedef struct {
+  uint32_t expires;
+  uint32_t lease_nip;
+  uint8_t lease_mac[6];
+  char hostname[20];
+  uint8_t pad[2];
+} dyn_lease;
+
+typedef struct option_val_s {
+  char *key;
+  uint16_t code;
+  void *val;
+  size_t len;
+} option_val_t;
+
+typedef struct __attribute__((__may_alias__)) server_config_s {
+  char *interface;                // interface to use
+  int ifindex;
+  uint32_t server_nip;
+  uint32_t port;
+  uint8_t server_mac[6];          // our MAC address (used only for ARP probing)
+  void *options[256];             // list of DHCP options loaded from the config file
+  /* start,end are in host order: we need to compare start <= ip <= end*/
+  uint32_t start_ip;              // start address of leases, in host order
+  uint32_t end_ip;                // end of leases, in host order
+  uint32_t max_lease_sec;         // maximum lease time (host order)
+  uint32_t min_lease_sec;         // minimum lease time a client can request
+  uint32_t max_leases;            // maximum number of leases (including reserved addresses)
+  uint32_t auto_time;             // how long should dhcpd wait before writing a config file.
+                                  // if this is zero, it will only write one on SIGUSR1
+  uint32_t decline_time;          // how long an address is reserved if a client returns a
+                                  // decline message
+  uint32_t conflict_time;         // how long an arp conflict offender is leased for
+  uint32_t offer_time;            // how long an offered address is reserved
+  uint32_t siaddr_nip;            // "next server" bootp option
+  char *lease_file;
+  char *pidfile;
+  char *notify_file;              // what to run whenever leases are written
+  char *sname;                    // bootp server name
+  char *boot_file;                // bootp boot file option
+  struct static_lease *static_leases; // List of ip/mac pairs to assign static leases
+} server_config_t;
+
+typedef struct __attribute__((__may_alias__)) server_state_s {
+  uint8_t rqcode;
+  int listensock;
+  dhcp_msg_t rcvd_pkt;
+  uint8_t* rqopt;
+  dhcp_msg_t send_pkt;
+  static_lease *sleases;
+  struct arg_list *dleases;
+} server_state_t;
+
+struct config_keyword {
+  char *keyword;
+  int (*handler)(const char *str, void *var);
+  void *var;
+  char *def;
+};
+
+static option_val_t options_list[] = {
+    {"lease"          , DHCP_NUM32  | 0x33, NULL, 0},
+    {"subnet"         , DHCP_IP     | 0x01, NULL, 0},
+    {"broadcast"      , DHCP_IP     | 0x1c, NULL, 0},
+    {"router"         , DHCP_IP     | 0x03, NULL, 0},
+    {"ipttl"          , DHCP_NUM8   | 0x17, NULL, 0},
+    {"mtu"            , DHCP_NUM16  | 0x1a, NULL, 0},
+    {"hostname"       , DHCP_STRING | 0x0c, NULL, 0},
+    {"domain"         , DHCP_STRING | 0x0f, NULL, 0},
+    {"search"         , DHCP_STRLST | 0x77, NULL, 0},
+    {"nisdomain"      , DHCP_STRING | 0x28, NULL, 0},
+    {"timezone"       , DHCP_NUM32  | 0x02, NULL, 0},
+    {"tftp"           , DHCP_STRING | 0x42, NULL, 0},
+    {"bootfile"       , DHCP_STRING | 0x43, NULL, 0},
+    {"bootsize"       , DHCP_NUM16  | 0x0d, NULL, 0},
+    {"rootpath"       , DHCP_STRING | 0x11, NULL, 0},
+    {"wpad"           , DHCP_STRING | 0xfc, NULL, 0},
+    {"serverid"       , DHCP_IP     | 0x36, NULL, 0},
+    {"message"        , DHCP_STRING | 0x38, NULL, 0},
+    {"vlanid"         , DHCP_NUM32  | 0x84, NULL, 0},
+    {"vlanpriority"   , DHCP_NUM32  | 0x85, NULL, 0},
+    {"dns"            , DHCP_IPLIST | 0x06, NULL, 0},
+    {"wins"           , DHCP_IPLIST | 0x2c, NULL, 0},
+    {"nissrv"         , DHCP_IPLIST | 0x29, NULL, 0},
+    {"ntpsrv"         , DHCP_IPLIST | 0x2a, NULL, 0},
+    {"lprsrv"         , DHCP_IPLIST | 0x09, NULL, 0},
+    {"swapsrv"        , DHCP_IP     | 0x10, NULL, 0},
+    {"routes"         , DHCP_STCRTS | 0x21, NULL, 0},
+    {"staticroutes"   , DHCP_STCRTS | 0x79, NULL, 0},
+    {"msstaticroutes" , DHCP_STCRTS | 0xf9, NULL, 0},
+};
+
+struct fd_pair { int rd; int wr; };
+static server_config_t gconfig;
+static server_state_t gstate;
+static uint8_t infomode;
+static struct fd_pair sigfd;
+static int constone = 1;
+
+// calculate options size.
+static int dhcp_opt_size(uint8_t *optionptr)
+{
+  int i = 0;
+  for(;optionptr[i] != 0xff; i++) if(optionptr[i] != 0x00) i += optionptr[i + 1] + 2 -1;
+  return i;
+}
+
+// calculates checksum for dhcp messeges.
+static uint16_t dhcp_checksum(void *addr, int count)
+{
+  int32_t sum = 0;
+  uint16_t tmp = 0, *source = (uint16_t *)addr;
+
+  while (count > 1)  {
+    sum += *source++;
+    count -= 2;
+  }
+  if (count > 0) {
+    *(uint8_t*)&tmp = *(uint8_t*)source;
+    sum += tmp;
+  }
+  while (sum >> 16) sum = (sum & 0xffff) + (sum >> 16);
+  return ~sum;
+}
+
+// gets information of INTERFACE and updates IFINDEX, MAC and IP
+static int get_interface(const char *interface, int *ifindex, uint32_t *oip, uint8_t *mac)
+{
+  struct ifreq req;
+  struct sockaddr_in *ip;
+  int fd = xsocket(AF_INET, SOCK_RAW, IPPROTO_RAW);
+
+  req.ifr_addr.sa_family = AF_INET;
+  strncpy(req.ifr_name, interface, IFNAMSIZ);
+  req.ifr_name[IFNAMSIZ-1] = '\0';
+
+  xioctl(fd, SIOCGIFFLAGS, &req);
+  
+  if (!(req.ifr_flags & IFF_UP)) return -1;
+  if (oip) {
+    xioctl(fd, SIOCGIFADDR, &req);
+    ip = (struct sockaddr_in*) &req.ifr_addr;
+    dbg("IP %s\n", inet_ntoa(ip->sin_addr));
+    *oip = ntohl(ip->sin_addr.s_addr);
+  }
+  if (ifindex) {
+    xioctl(fd, SIOCGIFINDEX, &req);
+    dbg("Adapter index %d\n", req.ifr_ifindex);
+    *ifindex = req.ifr_ifindex;
+  }
+  if (mac) {
+    xioctl(fd, SIOCGIFHWADDR, &req);
+    memcpy(mac, req.ifr_hwaddr.sa_data, 6);
+    dbg("MAC %02x:%02x:%02x:%02x:%02x:%02x\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
+  }
+  close(fd);
+  return 0;
+}
+
+/*
+ *logs messeges to syslog or console
+ *opening the log is still left with applet.
+ *FIXME: move to more relevent lib. probably libc.c
+ */
+static void infomsg(uint8_t infomode, char *s, ...)
+{
+  int used;
+  char *msg;
+  va_list p, t;
+
+  if (infomode == LOG_SILENT) return;
+  va_start(p, s);
+  va_copy(t, p);
+  used = vsnprintf(NULL, 0, s, t);
+  used++;
+  va_end(t);
+
+  msg = xmalloc(used);
+  vsnprintf(msg, used, s, p);
+  va_end(p);
+
+  if (infomode & LOG_SYSTEM) syslog(LOG_INFO, "%s", msg);
+  if (infomode & LOG_CONSOLE) printf("%s\n", msg);
+  free(msg);
+}
+
+/*
+ * Writes self PID in file PATH
+ * FIXME: libc implementation only writes in /var/run
+ * this is more generic as some implemenation may provide
+ * arguments to write in specific file. as dhcpd does.
+ */
+static void write_pid(char *path)
+{
+  int pidfile = open(path, O_CREAT | O_WRONLY | O_TRUNC, 0666);
+  if (pidfile > 0) {
+    char *pidbuf = utoa(getpid());
+    write(pidfile, pidbuf, strlen(pidbuf));
+    close(pidfile);
+  }
+}
+
+// Generic signal handler real handling is done in main funcrion.
+static void signal_handler(int sig)
+{
+  unsigned char ch = sig;
+  if (write(sigfd.wr, &ch, 1) != 1) dbg("can't send signal\n");
+}
+
+// signal setup for SIGUSR1 SIGTERM
+static int setup_signal()
+{
+  if (pipe((int *)&sigfd) < 0) {
+    dbg("signal pipe failed\n");
+    return -1;
+  }
+  fcntl(sigfd.wr , F_SETFD, FD_CLOEXEC);
+  fcntl(sigfd.rd , F_SETFD, FD_CLOEXEC);
+  int flags = fcntl(sigfd.wr, F_GETFL);
+  fcntl(sigfd.wr, F_SETFL, flags | O_NONBLOCK);
+  signal(SIGUSR1, signal_handler);
+  signal(SIGTERM, signal_handler);
+  return 0;
+}
+
+// String STR to UINT32 conversion strored in VAR
+static int strtou32(const char *str, void *var)
+{
+  char *endptr = NULL;
+  int base = 10;
+  errno=0;
+  *((uint32_t*)(var)) = 0;
+  if (str[0]=='0' && (str[1]=='x' || str[1]=='X')) {
+    base = 16;
+    str+=2;
+  }
+  long ret_val = strtol(str, &endptr, base);
+  if (errno) infomsg(infomode, "config : Invalid num %s",str);
+  else if (endptr && (*endptr!='\0'||endptr == str))
+      infomsg(infomode, "config : Not a valid num %s",str);
+  else *((uint32_t*)(var)) = (uint32_t)ret_val;
+  return 0;
+}
+
+// copy string STR in variable VAR
+static int strinvar(const char *str, void *var)
+{
+  char **dest = var;
+  if (*dest) free(*dest);
+  *dest = strdup(str);
+  return 0;
+}
+
+// IP String STR to binary data.
+static int striptovar(const char *str, void *var)
+{
+  in_addr_t addr;
+  *((uint32_t*)(var)) = 0;
+  if(!str) {
+    error_msg("config : NULL address string \n");
+    return -1;
+  }
+  if((addr = inet_addr(str)) == -1) {
+    error_msg("config : wrong address %s \n",str );
+    return -1;
+  }
+  *((uint32_t*)(var)) = (uint32_t)addr;
+  return 0;
+}
+
+// String to dhcp option conversion
+static int strtoopt(const char *str, void *var)
+{
+  char *option, *valstr, *grp, *tp;
+  uint32_t optcode = 0, inf = infomode, convtmp, mask, nip, router;
+  uint16_t flag = 0;
+  int count, size = ARRAY_LEN(options_list);
+
+  if (!*str) return 0;
+  if (!(option = strtok((char*)str, " \t="))) return -1;
+
+  infomode = LOG_SILENT;
+  strtou32(option, (uint32_t*)&optcode);
+  infomode = inf;
+
+  if (optcode > 0 && optcode < 256) { // raw option
+    for (count = 0; count < size; count++) {
+      if ((options_list[count].code & 0X00FF) == optcode) {
+        flag = (options_list[count].code & 0XFF00);
+        break;
+      }
+    }
+  } else { //string option
+    for (count = 0; count < size; count++) {
+      if (!strncmp(options_list[count].key, option, strlen(options_list[count].key))) {
+        flag = (options_list[count].code & 0XFF00);
+        optcode = (options_list[count].code & 0X00FF);
+        break;
+      }
+    }
+  }
+  if (count == size) {
+    infomsg(inf, "config : Obsolete OR Unknown Option : %s", option);
+    return -1;
+  }
+
+  if (!flag || !optcode) return -1;
+
+  if (!(valstr = strtok(NULL, " \t"))) {
+    dbg("config : option %s has no value defined.\n", option);
+    return -1;
+  }
+  dbg(" value : %-20s : ", valstr);
+  switch (flag) {
+  case DHCP_NUM32:
+    options_list[count].len = sizeof(uint32_t);
+    options_list[count].val = xmalloc(sizeof(uint32_t));
+    strtou32(valstr, &convtmp);
+    memcpy(options_list[count].val, &convtmp, sizeof(uint32_t));
+    break;
+  case DHCP_NUM16:
+    options_list[count].len = sizeof(uint16_t);
+    options_list[count].val = xmalloc(sizeof(uint16_t));
+    strtou32(valstr, &convtmp);
+    memcpy(options_list[count].val, &convtmp, sizeof(uint16_t));
+    break;
+  case DHCP_NUM8:
+    options_list[count].len = sizeof(uint8_t);
+    options_list[count].val = xmalloc(sizeof(uint8_t));
+    strtou32(valstr, &convtmp);
+    memcpy(options_list[count].val, &convtmp, sizeof(uint8_t));
+    break;
+  case DHCP_IP:
+    options_list[count].len = sizeof(uint32_t);
+    options_list[count].val = xmalloc(sizeof(uint32_t));
+    striptovar(valstr, options_list[count].val);
+    break;
+  case DHCP_STRING:
+    options_list[count].len = strlen(valstr);
+    options_list[count].val = strdup(valstr);
+    break;
+  case DHCP_IPLIST:
+    while(valstr){
+      options_list[count].val = xrealloc(options_list[count].val, options_list[count].len + sizeof(uint32_t));
+      striptovar(valstr, ((uint8_t*)options_list[count].val)+options_list[count].len);
+      options_list[count].len += sizeof(uint32_t);
+      valstr = strtok(NULL," \t");
+    }
+    break;
+  case DHCP_IPPLST:
+    break;
+  case DHCP_STCRTS:
+    /* Option binary format:
+     * mask [one byte, 0..32]
+     * ip [0..4 bytes depending on mask]
+     * router [4 bytes]
+     * may be repeated
+     * staticroutes 10.0.0.0/8 10.127.0.1, 10.11.12.0/24 10.11.12.1
+     */
+    grp = strtok(valstr, ",");;
+    while(grp){
+      while(*grp == ' ' || *grp == '\t') grp++;
+      tp = strchr(grp, '/');
+      if (!tp) error_exit("wrong formated static route option");
+      *tp = '\0';
+      mask = strtol(++tp, &tp, 10);
+      if (striptovar(grp, (uint8_t*)&nip)<0) error_exit("wrong formated static route option");
+      while(*tp == ' ' || *tp == '\t' || *tp == '-') tp++;
+      if (striptovar(tp, (uint8_t*)&router)<0) error_exit("wrong formated static route option");
+      options_list[count].val = xrealloc(options_list[count].val, options_list[count].len + 1 + mask/8 + 4);
+      memcpy(((uint8_t*)options_list[count].val)+options_list[count].len, &mask, 1);
+      options_list[count].len += 1;
+      memcpy(((uint8_t*)options_list[count].val)+options_list[count].len, &nip, mask/8);
+      options_list[count].len += mask/8;
+      memcpy(((uint8_t*)options_list[count].val)+options_list[count].len, &router, 4);
+      options_list[count].len += 4;
+      tp = NULL;
+      grp = strtok(NULL, ",");
+    }
+    break;
+  }
+  return 0;
+}
+
+// Reads Static leases from STR and updates inner structures.
+static int get_staticlease(const char *str, void *var)
+{
+  struct static_lease_s *sltmp;
+  char *tkmac, *tkip;
+  int count;
+
+  if (!*str) return 0;
+
+  if (!(tkmac = strtok((char*)str, " \t"))) {
+    infomsg(infomode, "config : static lease : mac not found");
+    return 0;
+  }
+  if (!(tkip = strtok(NULL, " \t"))) {
+    infomsg(infomode, "config : static lease : no ip bind to mac %s", tkmac);
+    return 0;
+  }
+  sltmp = xzalloc(sizeof(struct static_lease_s));
+  for (count = 0; count < 6; count++, tkmac++) {
+    errno = 0;
+    sltmp->mac[count] = strtol(tkmac, &tkmac, 16);
+    if (sltmp->mac[count]>255 || sltmp->mac[count]<0 || (*tkmac && *tkmac!=':') || errno) {
+      infomsg(infomode, "config : static lease : mac address wrong format");
+      free(sltmp);
+      return 0;
+    }
+  }
+  striptovar(tkip, &sltmp->nip);
+  sltmp->next = gstate.sleases;
+  gstate.sleases = sltmp;
+
+  return 0;
+}
+
+static struct config_keyword keywords[] = {
+// keyword          handler           variable address                default 
+  {"start"        , striptovar      , (void*)&gconfig.start_ip     , "192.168.0.20"},
+  {"end"          , striptovar      , (void*)&gconfig.end_ip       , "192.168.0.254"},
+  {"interface"    , strinvar        , (void*)&gconfig.interface    , "eth0"},
+  {"port"         , strtou32        , (void*)&gconfig.port         , "67"},
+  {"min_lease"    , strtou32        , (void*)&gconfig.min_lease_sec, "60"},
+  {"max_leases"   , strtou32        , (void*)&gconfig.max_leases   , "235"},
+  {"auto_time"    , strtou32        , (void*)&gconfig.auto_time    , "7200"},
+  {"decline_time" , strtou32        , (void*)&gconfig.decline_time , "3600"},
+  {"conflict_time", strtou32        , (void*)&gconfig.conflict_time, "3600"},
+  {"offer_time"   , strtou32        , (void*)&gconfig.offer_time   , "60"},
+  {"lease_file"   , strinvar        , (void*)&gconfig.lease_file   , "/var/lib/misc/dhcpd.leases"}, //LEASES_FILE
+  {"pidfile"      , strinvar        , (void*)&gconfig.pidfile      , "/var/run/dhcpd.pid"}, //DPID_FILE
+  {"siaddr"       , striptovar      , (void*)&gconfig.siaddr_nip   , "0.0.0.0"},
+  {"option"       , strtoopt        , (void*)&gconfig.options      , ""},
+  {"opt"          , strtoopt        , (void*)&gconfig.options      , ""},
+  {"notify_file"  , strinvar        , (void*)&gconfig.notify_file  , ""},
+  {"sname"        , strinvar        , (void*)&gconfig.sname        , ""},
+  {"boot_file"    , strinvar        , (void*)&gconfig.boot_file    , ""},
+  {"static_lease" , get_staticlease , (void*)&gconfig.static_leases, ""},
+};
+
+// Parses the server config file and updates the global server config accordingly.
+static int parse_server_config(char *config_file, struct config_keyword *confkey)
+{
+  FILE *fs = NULL;
+  char *confline_temp = NULL,*confline = NULL, *tk = NULL, *tokens[2] = {NULL, NULL};
+  int len, linelen, tcount, count, size = ARRAY_LEN(keywords);
+
+  for (count = 0; count < size; count++)
+    if (confkey[count].handler) confkey[count].handler(confkey[count].def, confkey[count].var);
+
+  if (!(fs = fopen(config_file, "r"))) perror_msg("%s", config_file);
+  for (len = 0, linelen = 0; fs;) {
+    len = getline(&confline_temp, (size_t*) &linelen, fs);
+    confline = confline_temp;
+    if (len <= 0) break;
+    for (; *confline == ' '; confline++, len--);
+    if ((confline[0] == '#') || (confline[0] == '\n')) goto free_conf_continue;
+    tk = strchr(confline, '#');
+    if (tk) {
+      for (; *(tk-1)==' ' || *(tk-1)=='\t'; tk--);
+      *tk = '\0';
+    }
+    tk = strchr(confline, '\n');
+    if (tk) {
+      for (; *(tk-1)==' ' || *(tk-1)=='\t'; tk--);
+      *tk = '\0';
+    }
+    for (tcount=0, tk=strtok(confline, " \t"); tk && (tcount < 2);
+        tcount++, tk=strtok(NULL,(tcount==1)?"":" \t")) {
+      while ((*tk == '\t') || (*tk == ' ')) tk++;
+      tokens[tcount] = xstrdup(tk);
+    }
+    if (tcount<=1) goto free_tk0_continue;
+    for (count = 0; count < size; count++) {
+      if (!strcmp(confkey[count].keyword,tokens[0])) {
+        dbg("got config : %15s : ", confkey[count].keyword);
+        if (confkey[count].handler(tokens[1], confkey[count].var) == 0)
+          dbg("%s \n", tokens[1]);
+        break;
+      }
+    }
+    if (tokens[1]) { free(tokens[1]); tokens[1] = NULL; }
+free_tk0_continue:
+    if (tokens[0]) { free(tokens[0]); tokens[0] = NULL; }
+free_conf_continue:
+    free(confline_temp);
+    confline_temp = NULL;
+  }
+  if (fs) fclose(fs);
+  return 0;
+}
+
+// opens UDP socket for listen
+static int open_listensock(void)
+{
+  struct sockaddr_in addr;
+  struct ifreq ifr;
+
+  if (gstate.listensock > 0) close(gstate.listensock);
+
+  dbg("Opening listen socket on *:%d %s\n", gconfig.port, gconfig.interface);
+  gstate.listensock = xsocket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
+  setsockopt(gstate.listensock, SOL_SOCKET, SO_REUSEADDR, &constone, sizeof(constone));
+  if (setsockopt(gstate.listensock, SOL_SOCKET, SO_BROADCAST, &constone, sizeof(constone)) == -1) {
+      dbg("OPEN : brodcast ioctl failed.\n");
+      close(gstate.listensock);
+      return -1;
+  }
+  memset(&ifr, 0, sizeof(ifr));
+  strncpy(ifr.ifr_name, gconfig.interface, IFNAMSIZ);
+  ifr.ifr_name[IFNAMSIZ -1] = '\0';
+  setsockopt(gstate.listensock, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
+
+  memset(&addr, 0, sizeof(addr));
+  addr.sin_family = AF_INET;
+  addr.sin_port = (flag_chk(FLAG_P))?htons(TT.port):htons(67); //SERVER_PORT
+  addr.sin_addr.s_addr = INADDR_ANY ;
+
+  if (bind(gstate.listensock, (struct sockaddr *) &addr, sizeof(addr))) {
+    close(gstate.listensock);
+    perror_exit("bind failed");
+  }
+  dbg("OPEN : success\n");
+  return 0;
+}
+
+// Sends data through raw socket.
+static int send_packet(uint8_t broadcast)
+{
+  struct sockaddr_ll dest_sll;
+  dhcp_raw_t packet;
+  unsigned padding;
+  int fd, result = -1;
+  uint8_t bmacaddr[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
+
+  memset(&packet, 0, sizeof(dhcp_raw_t));
+  memcpy(&packet.dhcp, &gstate.send_pkt, sizeof(dhcp_msg_t));
+
+  if ((fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
+    dbg("SEND : socket failed\n");
+    return -1;
+  }
+  memset(&dest_sll, 0, sizeof(dest_sll));
+  dest_sll.sll_family = AF_PACKET;
+  dest_sll.sll_protocol = htons(ETH_P_IP);
+  dest_sll.sll_ifindex = gconfig.ifindex;
+  dest_sll.sll_halen = 6;
+  memcpy(dest_sll.sll_addr, (broadcast)?bmacaddr:gstate.rcvd_pkt.chaddr , 6);
+
+  if (bind(fd, (struct sockaddr *) &dest_sll, sizeof(dest_sll)) < 0) {
+    dbg("SEND : bind failed\n");
+    close(fd);
+    return -1;
+  }
+  padding = 308 - 1 - dhcp_opt_size(gstate.send_pkt.options);
+  packet.iph.protocol = IPPROTO_UDP;
+  packet.iph.saddr = gconfig.server_nip;
+  packet.iph.daddr = (broadcast || (gstate.rcvd_pkt.ciaddr == 0))?INADDR_BROADCAST:gstate.rcvd_pkt.ciaddr;
+  packet.udph.source = htons(67);//SERVER_PORT
+  packet.udph.dest = htons(68); //CLIENT_PORT
+  packet.udph.len = htons(sizeof(dhcp_raw_t) - sizeof(struct iphdr) - padding);
+  packet.iph.tot_len = packet.udph.len;
+  packet.udph.check = dhcp_checksum(&packet, sizeof(dhcp_raw_t) - padding);
+  packet.iph.tot_len = htons(sizeof(dhcp_raw_t) - padding);
+  packet.iph.ihl = sizeof(packet.iph) >> 2;
+  packet.iph.version = IPVERSION;
+  packet.iph.ttl = IPDEFTTL;
+  packet.iph.check = dhcp_checksum(&packet.iph, sizeof(packet.iph));
+
+  result = sendto(fd, &packet, sizeof(dhcp_raw_t) - padding, 0,
+      (struct sockaddr *) &dest_sll, sizeof(dest_sll));
+
+  dbg("sendto %d\n", result);
+  close(fd);
+  if (result < 0) dbg("PACKET send error\n");
+  return result;
+}
+
+// Reads from UDP socket
+static int read_packet(void)
+{
+  int ret;
+
+  memset(&gstate.rcvd_pkt, 0, sizeof(dhcp_msg_t));
+  ret = read(gstate.listensock, &gstate.rcvd_pkt, sizeof(dhcp_msg_t));
+  if (ret < 0) {
+    dbg("Packet read error, ignoring. \n");
+    return ret; // returns -1
+  }
+  if (gstate.rcvd_pkt.cookie != htonl(DHCP_MAGIC)) {
+    dbg("Packet with bad magic, ignoring. \n");
+    return -2;
+  }
+  if (gstate.rcvd_pkt.op != 1) { //BOOTPREQUEST
+    dbg("Not a BOOT REQUEST ignoring. \n");
+    return -2;
+  }
+  if (gstate.rcvd_pkt.hlen != 6) {
+    dbg("hlen != 6 ignoring. \n");
+    return -2;
+  }
+  dbg("Received a packet. Size : %d \n", ret);
+  return ret;
+}
+
+// Preapres a dhcp packet with defaults and configs
+static uint8_t* prepare_send_pkt(void)
+{
+  memset((void*)&gstate.send_pkt, 0, sizeof(gstate.send_pkt));
+  gstate.send_pkt.op = 2; //BOOTPREPLY
+  gstate.send_pkt.htype = 1;
+  gstate.send_pkt.hlen = 6;
+  gstate.send_pkt.xid = gstate.rcvd_pkt.xid;
+  gstate.send_pkt.cookie = htonl(DHCP_MAGIC);
+  gstate.send_pkt.nsiaddr = gconfig.server_nip;
+  memcpy(gstate.send_pkt.chaddr, gstate.rcvd_pkt.chaddr, 16);
+  gstate.send_pkt.options[0] = DHCP_OPT_END;
+  return gstate.send_pkt.options;
+}
+
+// Sets a option value in dhcp packet's option field
+static uint8_t* set_optval(uint8_t *optptr, uint16_t opt, void *var, size_t len)
+{
+  while (*optptr != DHCP_OPT_END) optptr++;
+  *optptr++ = (uint8_t)(opt & 0x00FF);
+  *optptr++ = (uint8_t) len;
+  memcpy(optptr, var, len);
+  optptr += len;
+  *optptr = DHCP_OPT_END;
+  return optptr;
+}
+
+// Gets a option value from dhcp packet's option field
+static uint8_t* get_optval(uint8_t *optptr, uint16_t opt, void *var)
+{
+  size_t len;
+  uint8_t overloaded = 0;
+
+  while (1) {
+    while (*optptr == DHCP_OPT_PADDING) optptr++;
+    if ((*optptr & 0x00FF) == DHCP_OPT_END) break;
+    if ((*optptr & 0x00FF) == DHCP_OPT_OPTION_OVERLOAD) {
+      overloaded = optptr[2];
+      optptr += optptr[1] + 2;
+    }
+    len = optptr[1];
+    if (*optptr == (opt & 0x00FF))
+      switch (opt & 0xFF00) {
+        case DHCP_NUM32: // FALLTHROUGH
+        case DHCP_IP:
+          memcpy(var, optptr+2, sizeof(uint32_t));
+          optptr += len + 2;
+          return optptr;
+          break;
+        case DHCP_NUM16:
+          memcpy(var, optptr+2, sizeof(uint16_t));
+          optptr += len + 2;
+          return optptr;
+          break;
+        case DHCP_NUM8:
+          memcpy(var, optptr+2, sizeof(uint8_t));
+          optptr += len + 2;
+          return optptr;
+          break;
+        case DHCP_STRING:
+          var = xstrndup((char*) optptr, len);
+          optptr += len + 2;
+          return optptr;
+          break;
+      }
+    optptr += len + 2;
+  }
+  if ((overloaded == 1) | (overloaded == 3)) get_optval((uint8_t*)&gstate.rcvd_pkt.file, opt, var);
+  if ((overloaded == 2) | (overloaded == 3)) get_optval((uint8_t*)&gstate.rcvd_pkt.sname, opt, var);
+  return optptr;
+}
+
+// Retrives Requested Parameter list from dhcp req packet.
+static uint8_t get_reqparam(uint8_t **list)
+{
+  uint8_t len, *optptr;
+  if(*list) free(*list);
+  for (optptr = gstate.rcvd_pkt.options;
+      *optptr && *optptr!=((DHCP_OPT_PARAM_REQ) & 0x00FF); optptr+=optptr[1]+2);
+  len = *++optptr;
+  *list = xzalloc(len+1);
+  memcpy(*list, ++optptr, len);
+  return len;
+}
+
+// Sets values of req param in dhcp offer packet.
+static uint8_t* set_reqparam(uint8_t *optptr, uint8_t *list)
+{
+  uint8_t reqcode;
+  int count, size = ARRAY_LEN(options_list);
+
+  while (*list) {
+    reqcode = *list++;
+    for (count = 0; count < size; count++) {
+      if ((options_list[count].code & 0X00FF)==reqcode) {
+        if (!(options_list[count].len) || !(options_list[count].val)) break;
+        for (; *optptr && *optptr!=DHCP_OPT_END; optptr+=optptr[1]+2);
+        *optptr++ = (uint8_t) (options_list[count].code & 0x00FF);
+        *optptr++ = (uint8_t) options_list[count].len;
+        memcpy(optptr, options_list[count].val, options_list[count].len);
+        optptr += options_list[count].len;
+        *optptr = DHCP_OPT_END;
+        break;
+      }
+    }
+  }
+  return optptr;
+}
+
+static void run_notify(char **argv)
+{
+  struct stat sts;
+  volatile int error = 0;
+  pid_t pid;
+
+  if (stat(argv[0], &sts) == -1 && errno == ENOENT) {
+    infomsg(infomode, "notify file: %s : not exist.", argv[0]);
+    return;
+  }
+  fflush(NULL);
+
+  pid = vfork();
+  if (pid < 0) {
+    dbg("Fork failed.\n");
+    return;
+  }
+  if (!pid) {
+    execvp(argv[0], argv);
+    error = errno;
+    _exit(111);
+  }
+  if (error) {
+    waitpid(pid, NULL, 0);
+    errno = error;
+  }
+  dbg("script complete.\n");
+}
+
+static int write_leasefile(void)
+{
+  int fd;
+  uint32_t curr, tmp_time;
+  int64_t timestamp;
+  struct arg_list *listdls = gstate.dleases;
+  dyn_lease *dls;
+
+  if ((fd = open(gconfig.lease_file, O_WRONLY | O_CREAT | O_TRUNC)) < 0) {
+    perror_msg("can't open %s ", gconfig.lease_file);
+    return fd;
+  }
+
+  curr = timestamp = time(NULL);
+  timestamp = SWAP_BE64(timestamp);
+  writeall(fd, &timestamp, sizeof(timestamp));
+
+  while (listdls) {
+    dls = (dyn_lease*)listdls->arg;
+    tmp_time = dls->expires;
+    dls->expires -= curr;
+    if ((int32_t) dls->expires < 0) goto skip;
+    dls->expires = htonl(dls->expires);
+    writeall(fd, dls, sizeof(dyn_lease));
+skip:
+    dls->expires = tmp_time;
+    listdls = listdls->next;
+  }
+  close(fd);
+  if (gconfig.notify_file) {
+    char *argv[3];
+    argv[0] = gconfig.notify_file;
+    argv[1] = gconfig.lease_file;
+    argv[2] = NULL;
+    run_notify(argv);
+  }
+  return 0;
+}
+
+// Update max lease time from options.
+static void set_maxlease(void)
+{
+  int count, size = ARRAY_LEN(options_list);
+  for (count = 0; count < size; count++)
+    if (options_list[count].val && options_list[count].code == (DHCP_OPT_LEASE_TIME)) {
+      gconfig.max_lease_sec = *((uint32_t*)options_list[count].val);
+      break;
+    }
+  if (!gconfig.max_lease_sec) gconfig.max_lease_sec = (60*60*24*10);// DEFAULT_LEASE_TIME;
+}
+
+// Returns lease time for client.
+static uint32_t get_lease(uint32_t req_exp)
+{
+  uint32_t now = time(NULL);
+  req_exp = req_exp - now;
+  if ((req_exp <= 0) || (req_exp > gconfig.max_lease_sec))
+    return gconfig.max_lease_sec;
+
+  if (req_exp < gconfig.min_lease_sec)
+    return gconfig.min_lease_sec;
+
+  return req_exp;
+}
+
+// Verify ip NIP in current leases ( assigned or not)
+static int verifyip_in_lease(uint32_t nip, uint8_t mac[6])
+{
+  static_lease *sls;
+  struct arg_list *listdls;
+
+  for (listdls = gstate.dleases; listdls; listdls = listdls->next) {
+    if (((dyn_lease*) listdls->arg)->lease_nip == nip) {
+      if (((int32_t)(((dyn_lease*) listdls->arg)->expires) - time(NULL)) < 0)
+        return 0;
+      return -1;
+    }
+    if (!memcmp(((dyn_lease*) listdls->arg)->lease_mac, mac, 6)) return -1;
+  }
+  for (sls = gstate.sleases; sls; sls = sls->next)
+    if (sls->nip == nip) return -2;
+
+  if ((ntohl(nip) < gconfig.start_ip) || (ntohl(nip) > gconfig.end_ip))
+    return -3;
+
+  return 0;
+}
+
+// add ip assigned_nip to dynamic lease.
+static int addip_to_lease(uint32_t assigned_nip, uint8_t mac[6], uint32_t *req_exp, char *hostname, uint8_t update)
+{
+  dyn_lease *dls;
+  struct arg_list *listdls = gstate.dleases;
+  uint32_t now = time(NULL);
+
+  while (listdls) {
+    if (!memcmp(((dyn_lease*) listdls->arg)->lease_mac, mac, 6)) {
+      if (update) *req_exp = get_lease(*req_exp + ((dyn_lease*) listdls->arg)->expires);
+      ((dyn_lease*) listdls->arg)->expires = *req_exp + now;
+      return 0;
+    }
+    listdls = listdls->next;
+  }
+
+  dls = xzalloc(sizeof(dyn_lease));
+  memcpy(dls->lease_mac, mac, 6);
+  dls->lease_nip = assigned_nip;
+  if (hostname) memcpy(dls->hostname, hostname, 20);
+
+  if (update) *req_exp = get_lease(*req_exp + now);
+  dls->expires = *req_exp + now;
+
+  listdls = xzalloc(sizeof(struct arg_list));
+  listdls->next = gstate.dleases;
+  listdls->arg = (char*)dls;
+  gstate.dleases = listdls;
+
+  return 0;
+}
+
+// delete ip assigned_nip from dynamic lease.
+static int delip_from_lease(uint32_t assigned_nip, uint8_t mac[6], uint32_t del_time)
+{
+  struct arg_list *listdls = gstate.dleases;
+
+  while (listdls) {
+    if (!memcmp(((dyn_lease*) listdls->arg)->lease_mac, mac, 6)) {
+      ((dyn_lease*) listdls->arg)->expires = del_time + time(NULL);
+      return 0;
+    }
+    listdls = listdls->next;
+  }
+  return -1;
+}
+
+// returns a IP from static, dynamic leases or free ip pool, 0 otherwise.
+static uint32_t getip_from_pool(uint32_t req_nip, uint8_t mac[6], uint32_t *req_exp, char *hostname)
+{
+  uint32_t nip = 0;
+  static_lease *sls = gstate.sleases;
+  struct arg_list *listdls = gstate.dleases, *tmp = NULL;
+
+  if (req_nip && (!verifyip_in_lease(req_nip, mac))) nip = req_nip;
+
+  if (!nip) {
+    while (listdls) {
+      if (!memcmp(((dyn_lease*)listdls->arg)->lease_mac, mac, 6)) {
+        nip = ((dyn_lease*)listdls->arg)->lease_nip;
+        if (tmp) tmp->next = listdls->next;
+        else gstate.dleases = listdls->next;
+        free(listdls->arg);
+        free(listdls);
+        if (verifyip_in_lease(nip, mac) < 0) nip = 0;
+        break;
+      }
+      tmp = listdls;
+      listdls = listdls->next;
+    }
+  }
+  if (!nip) {
+    while (sls) {
+      if (memcmp(sls->mac, mac, 6) == 0) {
+        nip = sls->nip;
+        break;
+      }
+      sls = sls->next;
+    }
+  }
+  if (!nip) {
+    for (nip = htonl(gconfig.start_ip); ntohl(nip) <= gconfig.end_ip; ) {
+      if (!verifyip_in_lease(nip, mac)) break;
+      nip = ntohl(nip);
+      nip = htonl(++nip);
+    }
+    if (ntohl(nip) > gconfig.end_ip) {
+      nip = 0;
+      infomsg(infomode, "can't find free IP in IP Pool.");
+    }
+  }
+  if (nip) addip_to_lease(nip, mac, req_exp, hostname, 1);
+  return nip;
+}
+
+static int read_leasefile(void)
+{
+  uint32_t passed, ip;
+  int32_t tmp_time;
+  int64_t timestamp;
+  dyn_lease *dls;
+  int ret = -1, fd = open(gconfig.lease_file, O_RDONLY);
+
+  if (fd < 0) return fd;
+  dls = xzalloc(sizeof(dyn_lease));
+
+  if (read(fd, &timestamp, sizeof(timestamp)) != sizeof(timestamp)) goto error_exit;
+
+  timestamp = SWAP_BE64(timestamp);
+  passed = time(NULL) - timestamp;
+  if ((uint64_t)passed > 12 * 60 * 60) goto error_exit;
+
+  while (read(fd, dls, sizeof(dyn_lease)) == sizeof(dyn_lease)) {
+    ip = ntohl(dls->lease_nip);
+    if (ip >= gconfig.start_ip && ip <= gconfig.end_ip) {
+      tmp_time = ntohl(dls->expires) - passed;
+      if (tmp_time < 0) continue;
+      addip_to_lease(dls->lease_nip, dls->lease_mac, (uint32_t*)&tmp_time, dls->hostname, 0);
+    }
+  }
+  ret = 0;
+error_exit:
+  free(dls);
+  close(fd);
+  return ret;
+}
+
+void dhcpd_main(void)
+{
+  struct timeval tv;
+  int retval;
+  uint8_t *optptr, msgtype = 0;
+  uint32_t waited = 0, serverid = 0, requested_nip = 0;
+  uint32_t reqested_lease = 0, ip_pool_size = 0;
+  char *hstname = NULL;
+  fd_set rfds;
+
+  infomode = LOG_CONSOLE;
+  if (!(flag_chk(FLAG_f))) {
+    daemonize();
+    infomode = LOG_SILENT;
+  }
+  if (flag_chk(FLAG_S)) {
+        openlog("UDHCPD :", LOG_PID, LOG_DAEMON);
+        infomode |= LOG_SYSTEM;
+  }
+  setlinebuf(stdout);
+  parse_server_config((toys.optc==1)?toys.optargs[0]:"/etc/dhcpd.conf", keywords); //DHCPD_CONF_FILE
+  infomsg(infomode, "toybox dhcpd started");
+  gconfig.start_ip = ntohl(gconfig.start_ip);
+  gconfig.end_ip = ntohl(gconfig.end_ip);
+  ip_pool_size = gconfig.end_ip - gconfig.start_ip + 1;
+  if (gconfig.max_leases > ip_pool_size) {
+    error_msg("max_leases=%u is too big, setting to %u", (unsigned) gconfig.max_leases, ip_pool_size);
+    gconfig.max_leases = ip_pool_size;
+  }
+  write_pid(gconfig.pidfile);
+  set_maxlease();
+  read_leasefile();
+
+  if (get_interface(gconfig.interface, &gconfig.ifindex, &gconfig.server_nip,
+        gconfig.server_mac)<0)
+    perror_exit("Failed to get interface %s", gconfig.interface);
+  gconfig.server_nip = htonl(gconfig.server_nip);
+
+  setup_signal();
+  open_listensock();
+  fcntl(gstate.listensock, F_SETFD, FD_CLOEXEC);
+
+  for (;;) {
+    uint32_t timestmp = time(NULL);
+    FD_ZERO(&rfds);
+    FD_SET(gstate.listensock, &rfds);
+    FD_SET(sigfd.rd, &rfds);
+    tv.tv_sec = gconfig.auto_time - waited;
+    tv.tv_usec = 0;
+    retval = 0;
+    serverid = 0;
+    msgtype = 0;
+
+    int maxfd = (sigfd.rd > gstate.listensock)? sigfd.rd : gstate.listensock;
+    dbg("select waiting ....\n");
+    retval = select(maxfd + 1, &rfds, NULL, NULL, (gconfig.auto_time?&tv:NULL));
+    if (retval < 0) {
+      if (errno == EINTR) {
+        waited += (unsigned) time(NULL) - timestmp;
+        continue;
+      }
+      dbg("Error in select wait again...\n");
+      continue;
+    }
+    if (!retval) { // Timed out 
+      dbg("select wait Timed Out...\n");
+      waited = 0;
+      write_leasefile();
+      if (get_interface(gconfig.interface, &gconfig.ifindex, &gconfig.server_nip, gconfig.server_mac)<0)
+        perror_exit("Interface lost %s\n", gconfig.interface);
+      gconfig.server_nip = htonl(gconfig.server_nip);
+      continue;
+    }
+    if (FD_ISSET(sigfd.rd, &rfds)) { // Some Activity on RDFDs : is signal 
+      unsigned char sig;
+      if (read(sigfd.rd, &sig, 1) != 1) {
+        dbg("signal read failed.\n");
+        continue;
+      }
+      switch (sig) {
+      case SIGUSR1:
+        infomsg(infomode, "Received SIGUSR1");
+        write_leasefile();
+        continue;
+      case SIGTERM:
+        infomsg(infomode, "Received SIGTERM");
+        write_leasefile();
+        unlink(gconfig.pidfile);
+        exit(0);
+        break;
+      default: break;
+      }
+    }
+    if (FD_ISSET(gstate.listensock, &rfds)) { // Some Activity on RDFDs : is socket
+      dbg("select listen sock read\n");
+      if (read_packet() < 0) {
+        open_listensock();
+        continue;
+      }
+      waited += time(NULL) - timestmp;
+      get_optval((uint8_t*)&gstate.rcvd_pkt.options, DHCP_OPT_MESSAGE_TYPE, &gstate.rqcode);
+      if (gstate.rqcode == 0 || gstate.rqcode < DHCPDISCOVER 
+          || gstate.rqcode > DHCPINFORM) {
+        dbg("no or bad message type option, ignoring packet.\n");
+        continue;
+      }
+      get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_SERVER_ID, &serverid);
+      if (serverid && (serverid != gconfig.server_nip)) {
+        dbg("server ID doesn't match, ignoring packet.\n");
+        continue;
+      }
+      switch (gstate.rqcode) {
+        case DHCPDISCOVER:
+          msgtype = DHCPOFFER;
+          dbg("Message Type : DHCPDISCOVER\n");
+          get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_REQUESTED_IP, &requested_nip);
+          get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_HOST_NAME, &hstname);
+          reqested_lease = gconfig.offer_time;
+          get_reqparam(&gstate.rqopt);
+          optptr = prepare_send_pkt();
+          gstate.send_pkt.yiaddr = getip_from_pool(requested_nip, gstate.rcvd_pkt.chaddr, &reqested_lease, hstname);
+          if(!gstate.send_pkt.yiaddr){
+            msgtype = DHCPNAK;
+            optptr = set_optval(optptr, DHCP_OPT_MESSAGE_TYPE, &msgtype, 1);
+            send_packet(1);
+            break;
+          }
+          get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_LEASE_TIME, &reqested_lease);
+          reqested_lease = htonl(get_lease(reqested_lease + time(NULL)));
+          optptr = set_optval(optptr, DHCP_OPT_MESSAGE_TYPE, &msgtype, 1);
+          optptr = set_optval(optptr, DHCP_OPT_SERVER_ID, &gconfig.server_nip, 4);
+          optptr = set_optval(optptr, DHCP_OPT_LEASE_TIME, &reqested_lease, 4);
+          optptr = set_reqparam(optptr, gstate.rqopt);
+          send_packet(1);
+          break;
+        case DHCPREQUEST:
+          msgtype = DHCPACK;
+          dbg("Message Type : DHCPREQUEST\n");
+          optptr = prepare_send_pkt();
+          get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_REQUESTED_IP, &requested_nip);
+          get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_LEASE_TIME, &reqested_lease);
+          get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_HOST_NAME, &hstname);
+          gstate.send_pkt.yiaddr = getip_from_pool(requested_nip, gstate.rcvd_pkt.chaddr, &reqested_lease, hstname);
+          if (!serverid) reqested_lease = gconfig.max_lease_sec;
+          if (!gstate.send_pkt.yiaddr) {
+            msgtype = DHCPNAK;
+            optptr = set_optval(optptr, DHCP_OPT_MESSAGE_TYPE, &msgtype, 1);
+            send_packet(1);
+            break;
+          }
+          optptr = set_optval(optptr, DHCP_OPT_MESSAGE_TYPE, &msgtype, 1);
+          optptr = set_optval(optptr, DHCP_OPT_SERVER_ID, &gconfig.server_nip, 4);
+          reqested_lease = htonl(reqested_lease);
+          optptr = set_optval(optptr, DHCP_OPT_LEASE_TIME, &reqested_lease, 4);
+          send_packet(1);
+          write_leasefile();
+          break;
+        case DHCPDECLINE:// FALL THROUGH
+        case DHCPRELEASE:
+          dbg("Message Type : DHCPDECLINE or DHCPRELEASE \n");
+          get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_SERVER_ID, &serverid);
+          if (serverid != gconfig.server_nip) break;
+          get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_REQUESTED_IP, &requested_nip);
+          delip_from_lease(requested_nip, gstate.rcvd_pkt.chaddr, (gstate.rqcode==DHCPRELEASE)?0:gconfig.decline_time);
+          break;
+        default:
+          dbg("Message Type : %u\n", gstate.rqcode);
+          break;
+      }
+    }
+  }
+}