Справочник по консольным командам Toybox для Android 12


  Ver.0.8.4     Ver.0.8.9     Pending  

Путь: Toys/Pending, команды версии: Ver.4     Ver.9

Комментарии в файле dhcpd.c :

Команд: 2


dhcpd

usage: dhcpd [-46fS] [-i IFACE] [-P N] [CONFFILE]

  • -f Запустить на переднем плане
  • -i Интерфейс для использования
  • -S Журнала в системный журнал также
  • -P N Использовать порт N (по умолчанию ipv4 67, ipv6 547)
  • -4, -6 Запуск в качестве сервера DHCPv4 или DHCPv6

  • usage: dhcpd [-46fS] [-i IFACE] [-P N] [CONFFILE]

  • -f Run in foreground
  • -i Interface to use
  • -S Log to syslog too
  • -P N Use port N (default ipv4 67, ipv6 547)
  • -4, -6 Run as a DHCPv4 or DHCPv6 server

  • debug_dhcp

    G_DHCP
      bool "отладка сообщений ВКЛ/ВЫКЛ"
      по умолчанию н
      зависит от DHCPD


    G_DHCP
      bool "debugging messeges ON/OFF"
      default n
      depends on DHCPD


    Исходный текст в файле dhcpd.c

    /*
     * TODO
     * - Working as an relay agent
     * - Rapid commit option support
     * - Additional packet options (commented on the middle of sources)
     * - Create common modules
     */
    
    #define FOR_dhcpd
    
    #include "toys.h"
    #include <linux/sockios.h> 
    #include <linux/if_ether.h>
    
    // Todo: headers not in posix
    #include <netinet/ip.h>
    #include <netinet/ip6.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 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 DHCP6SOLICIT        1
    #define DHCP6ADVERTISE      2   // server -> client
    #define DHCP6REQUEST        3
    #define DHCP6CONFIRM        4
    #define DHCP6RENEW          5
    #define DHCP6REBIND         6
    #define DHCP6REPLY          7   // server -> client
    #define DHCP6RELEASE        8
    #define DHCP6DECLINE        9
    #define DHCP6RECONFIGURE    10  // server -> client
    #define DHCP6INFOREQUEST    11
    #define DHCP6RELAYFLOW      12  // relay -> relay/server
    #define DHCP6RELAYREPLY     13  // server/relay -> relay
    
    #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
    
    // DHCPv6 option codes (partial). See RFC 3315
    #define DHCP6_OPT_CLIENTID      1
    #define DHCP6_OPT_SERVERID      2
    #define DHCP6_OPT_IA_NA         3
    #define DHCP6_OPT_IA_ADDR       5
    #define DHCP6_OPT_ORO           6
    #define DHCP6_OPT_PREFERENCE    7
    #define DHCP6_OPT_ELAPSED_TIME  8
    #define DHCP6_OPT_RELAY_MSG     9
    #define DHCP6_OPT_STATUS_CODE   13
    #define DHCP6_OPT_IA_PD         25
    #define DHCP6_OPT_IA_PREFIX     26
    
    #define DHCP6_STATUS_SUCCESS        0
    #define DHCP6_STATUS_NOADDRSAVAIL   2
    
    #define DHCP6_DUID_LLT    1
    #define DHCP6_DUID_EN     2
    #define DHCP6_DUID_LL     3
    #define DHCP6_DUID_UUID   4
    
    GLOBALS(
        char *iface;
        long port;
    )
    
    struct config_keyword {
      char *keyword;
      int (*handler)(const char *str, void *var);
      void *var;
      char *def;
    };
    
    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)) dhcp6_msg_s {
      uint8_t msgtype;
      uint8_t transaction_id[3];
      uint8_t options[524];
    } dhcp6_msg_t;
    
    typedef struct __attribute__((packed)) dhcp_raw_s {
      struct iphdr iph;
      struct udphdr udph;
      dhcp_msg_t dhcp;
    } dhcp_raw_t;
    
    typedef struct __attribute__((packed)) dhcp6_raw_s {
      struct ip6_hdr iph;
      struct udphdr udph;
      dhcp6_msg_t dhcp6;
    } dhcp6_raw_t;
    
    typedef struct static_lease_s {
      struct static_lease_s *next;
      uint32_t nip;
      int mac[6];
    } static_lease;
    
    typedef struct static_lease6_s {
      struct static_lease6_s *next;
      uint16_t duid_len;
      uint16_t ia_type;
      uint32_t iaid;
      uint8_t nip6[16];
      uint8_t duid[20];
    } static_lease6;
    
    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 {
      uint16_t duid_len;
      uint16_t ia_type;
      uint32_t expires;
      uint32_t iaid;
      uint8_t lease_nip6[16];
      uint8_t duid[20];
    } dyn_lease6;
    
    typedef struct option_val_s {
      char *key;
      uint16_t code;
      void *val;
      size_t len;
    } option_val_t;
    
    struct __attribute__((packed)) optval_duid_llt {
      uint16_t type;
      uint16_t hwtype;
      uint32_t time;
      uint8_t lladdr[];   //flexible
    };
    
    struct __attribute__((packed)) optval_ia_na {
      uint32_t iaid;
      uint32_t t1, t2;
      uint8_t optval[];   //flexible
    };
    struct __attribute__((packed)) optval_ia_addr {
      uint8_t ipv6_addr[16];
      uint32_t pref_lifetime;
      uint32_t valid_lifetime;
    };
    struct __attribute__((packed)) optval_status_code {
      uint16_t status_code;
      uint8_t status_msg[]; //flexible
    };
    
    typedef struct __attribute__((__may_alias__)) server_config_s {
      char *interface;                // interface to use
      int ifindex;
      uint8_t server_nip6[16];
      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
      uint8_t start_ip6[16];          // start address of leases, in IPv6 mode
      uint8_t end_ip6[16];            // end of leases, in IPv6 mode
      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 *lease6_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
      uint32_t pref_lifetime;
      uint32_t valid_lifetime;
      uint32_t t1,t2;
      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 client_nip6[16];
      uint32_t client_port;
      uint8_t rqcode;
      int listensock;
      union {
        dhcp_msg_t rcvd_pkt;
        dhcp6_msg_t rcvd_pkt6;
      } rcvd;
      uint8_t* rqopt;
      union {
        dhcp_msg_t send_pkt;
        dhcp6_msg_t send_pkt6;
      } send;
      union {
        static_lease *sleases;
        static_lease6 *sleases6;
      } leases;
      struct arg_list *dleases;
    } server_state_t;
    
    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;
    static sa_family_t addr_version = AF_INET;
    
    // 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, void *oip,
        uint8_t *mac)
    {
      struct ifreq req;
      struct sockaddr_in *ip;
      struct sockaddr_in6 ip6;
      int fd = xsocket(addr_version, SOCK_RAW, IPPROTO_RAW);
      char ipv6_addr[40] = {0,};
    
      req.ifr_addr.sa_family = addr_version;
      xstrncpy(req.ifr_name, (char *)interface, IFNAMSIZ);
    
      xioctl(fd, SIOCGIFFLAGS, &req);
    
      if (!(req.ifr_flags & IFF_UP)) return -1;
    
      if (addr_version == AF_INET6) {
    
        FILE *fd6 = fopen("/proc/net/if_inet6", "r");
        uint8_t *oip6 = (uint8_t*)oip;
        int i;
    
        while(fgets(toybuf, sizeof(toybuf), fd6)) {
          if (!strstr(toybuf, interface))
            continue;
    
          if (sscanf(toybuf, "%32s \n", ipv6_addr) == 1)
            break;
        }
        fclose(fd6);
    
        if (oip6) {
          char *ptr = ipv6_addr+sizeof(ipv6_addr)-1;
    
          // convert giant hex string into colon-spearated ipv6 address by
          // inserting ':' every 4 characters.
          for (i = 32; i; i--)
            if ((*(ptr--) = ipv6_addr[i])) if (!(i&3)) *(ptr--) = ':';
    
          dbg("ipv6 %s\n", ipv6_addr);
          if(inet_pton(AF_INET6, ipv6_addr, &ip6.sin6_addr) <= 0)
            error_msg("inet : the ipv6 address is not proper");
          else
            memcpy(oip6, ip6.sin6_addr.s6_addr32, sizeof(uint32_t)*4);
        }
      } else {
        uint32_t *oip4 = (uint32_t*)oip;
        if (oip4) {
          xioctl(fd, SIOCGIFADDR, &req);
          ip = (struct sockaddr_in*) &req.ifr_addr;
          dbg("IP %s\n", inet_ntoa(ip->sin_addr));
          *oip4 = 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[12];
    
        sprintf(pidbuf, "%u", (unsigned)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)
    {
      *((uint32_t*)(var)) = 0;
      if(!str) {
        error_msg("config : NULL address string \n");
        return -1;
      }
      if((inet_pton(AF_INET6, str, var)<=0) && (inet_pton(AF_INET, str, var)<=0)) {
        error_msg("config : wrong address %s \n", str);
        return -1;
      }
      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 formatted static route option");
          *tp = '\0';
          mask = strtol(++tp, &tp, 10);
          if (striptovar(grp, (uint8_t*)&nip)<0) error_exit("wrong formatted static route option");
          while(*tp == ' ' || *tp == '\t' || *tp == '-') tp++;
          if (striptovar(tp, (uint8_t*)&router)<0) error_exit("wrong formatted 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.leases.sleases;
      gstate.leases.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
      {"lease6_file"  , strinvar        , (void*)&gconfig.lease6_file  , "/var/lib/misc/dhcpd6.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, ""},
      {"start6"       , striptovar      , (void*)&gconfig.start_ip6    , "2001:620:40b:555::100"},
      {"end6"         , striptovar      , (void*)&gconfig.end_ip6      , "2001:620:40b:555::200"},
      {"preferred_lifetime" , strtou32  , (void*)&gconfig.pref_lifetime, "3600"},
      {"valid_lifetime"     , strtou32  , (void*)&gconfig.valid_lifetime, "7200"},
      {"t1"           , strtou32        , (void*)&gconfig.t1           , "3600"},
      {"t2"           , strtou32        , (void*)&gconfig.t2           , "5400"},
    };
    
    // 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 ipv6 packets
    static int open_listensock6(void)
    {
      struct sockaddr_in6 addr6;
      struct ipv6_mreq mreq;
    
      if (gstate.listensock > 0) close(gstate.listensock);
    
      dbg("Opening listen socket on *:%d %s\n", gconfig.port, gconfig.interface);
    
      gstate.listensock = xsocket(PF_INET6, SOCK_DGRAM, 0);
      setsockopt(gstate.listensock, SOL_SOCKET, SO_REUSEADDR, &constone, sizeof(constone));
      setsockopt(gstate.listensock, IPPROTO_IPV6, IPV6_CHECKSUM, &constone, sizeof(constone));
    
      if (setsockopt(gstate.listensock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &constone,
            sizeof(constone)) == -1) {
        error_msg("failed to receive ipv6 packets.\n");
        close(gstate.listensock);
        return -1;
      }
    
      setsockopt(gstate.listensock, SOL_SOCKET, SO_BINDTODEVICE, gconfig.interface, strlen(gconfig.interface)+1);
    
      memset(&addr6, 0, sizeof(addr6));
      addr6.sin6_family = AF_INET6;
      addr6.sin6_port = htons(gconfig.port); //SERVER_PORT
      addr6.sin6_scope_id = if_nametoindex(gconfig.interface);
      //Listening for multicast packet
      inet_pton(AF_INET6, "ff02::1:2", &addr6.sin6_addr);
    
      if (bind(gstate.listensock, (struct sockaddr *) &addr6, sizeof(addr6)) == -1) {
        close(gstate.listensock);
        perror_exit("bind failed");
      }
    
      memset(&mreq, 0, sizeof(mreq));
      mreq.ipv6mr_interface = if_nametoindex(gconfig.interface);
      memcpy(&mreq.ipv6mr_multiaddr, &addr6.sin6_addr, sizeof(addr6.sin6_addr));
    
      if(setsockopt(gstate.listensock, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq, sizeof(mreq)) == -1) {
        error_msg("failed to join a multicast group.\n");
        close(gstate.listensock);
        return -1;
      }
    
      dbg("OPEN : success\n");
      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) {
        error_msg("failed to receive brodcast packets.\n");
        close(gstate.listensock);
        return -1;
      }
      memset(&ifr, 0, sizeof(ifr));
      xstrncpy(ifr.ifr_name, gconfig.interface, IFNAMSIZ);
      setsockopt(gstate.listensock, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
    
      memset(&addr, 0, sizeof(addr));
      addr.sin_family = AF_INET;
      addr.sin_port = htons(gconfig.port); //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;
    }
    
    static int send_packet6(uint8_t relay, uint8_t *client_lla, uint16_t optlen)
    {
      struct sockaddr_ll dest_sll;
      dhcp6_raw_t packet;
      unsigned padding;
      int fd, result = -1;
    
      memset(&packet, 0, sizeof(dhcp6_raw_t));
      memcpy(&packet.dhcp6, &gstate.send.send_pkt6, sizeof(dhcp6_msg_t));
      padding = sizeof(packet.dhcp6.options) - optlen;
    
      if ((fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IPV6))) < 0) {
        dbg("SEND : ipv6 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_IPV6);
      dest_sll.sll_ifindex = gconfig.ifindex;
      dest_sll.sll_halen = ETH_ALEN;
      memcpy(dest_sll.sll_addr, client_lla, sizeof(uint8_t)*6);
    
      if (bind(fd, (struct sockaddr *) &dest_sll, sizeof(dest_sll)) < 0) {
        dbg("SEND : bind failed\n");
        close(fd);
        return -1;
      }
      memcpy(&packet.iph.ip6_src, &gconfig.server_nip6, sizeof(uint32_t)*4);
      memcpy(&packet.iph.ip6_dst, &gstate.client_nip6, sizeof(uint32_t)*4);
    
      packet.udph.source = htons(gconfig.port); //SERVER_PORT
      packet.udph.dest = gstate.client_port; //CLIENT_PORT
      packet.udph.len = htons(sizeof(dhcp6_raw_t) - sizeof(struct ip6_hdr) - padding);
      packet.iph.ip6_ctlun.ip6_un1.ip6_un1_plen = htons(ntohs(packet.udph.len) + 0x11);
      packet.udph.check = dhcp_checksum(&packet, sizeof(dhcp6_raw_t) - padding);
      packet.iph.ip6_ctlun.ip6_un1.ip6_un1_flow = htonl(0x60000000);
      packet.iph.ip6_ctlun.ip6_un1.ip6_un1_plen = packet.udph.len;
      packet.iph.ip6_ctlun.ip6_un1.ip6_un1_nxt = IPPROTO_UDP;
      packet.iph.ip6_ctlun.ip6_un1.ip6_un1_hlim = 0x64;
    
      result = sendto(fd, &packet, sizeof(dhcp6_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;
    }
    
    // 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.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.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.send_pkt.options);
      packet.iph.protocol = IPPROTO_UDP;
      packet.iph.saddr = gconfig.server_nip;
      packet.iph.daddr = (broadcast || (gstate.rcvd.rcvd_pkt.ciaddr == 0))?
        INADDR_BROADCAST : gstate.rcvd.rcvd_pkt.ciaddr;
      packet.udph.source = htons(gconfig.port);//SERVER_PORT
      packet.udph.dest = gstate.client_port; //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;
    }
    
    static int read_packet6(void)
    {
      int ret;
      struct sockaddr_in6 c_addr;
      socklen_t c_addr_size = sizeof(c_addr);
    
      memset(&gstate.rcvd.rcvd_pkt6, 0, sizeof(dhcp6_msg_t));
      ret = recvfrom(gstate.listensock, &gstate.rcvd.rcvd_pkt6, sizeof(dhcp6_msg_t),
          0, (struct sockaddr*) &c_addr, &c_addr_size);
      memcpy(gstate.client_nip6, &c_addr.sin6_addr, sizeof(uint32_t)*4);
      memcpy(&gstate.client_port, &c_addr.sin6_port, sizeof(uint32_t));
      if (ret < 0) {
        dbg("Packet read error, ignoring. \n");
        return ret; // returns -1
      }
      if (gstate.rcvd.rcvd_pkt6.msgtype < 1) {
        dbg("Bad message type, igroning. \n");
        return -2;
      }
    
      dbg("Received an ipv6 packet. Size : %d \n", ret);
      return ret;
    }
    
    // Reads from UDP socket
    static int read_packet(void)
    {
      int ret;
      struct sockaddr_in c_addr;
      socklen_t c_addr_size = sizeof(c_addr);
    
      memset(&gstate.rcvd.rcvd_pkt, 0, sizeof(dhcp_msg_t));
      ret = recvfrom(gstate.listensock, &gstate.rcvd.rcvd_pkt, sizeof(dhcp_msg_t),
          0, (struct sockaddr*) &c_addr, &c_addr_size);
      memcpy(&gstate.client_port, &c_addr.sin_port, sizeof(uint32_t));
      /*ret = read(gstate.listensock, &gstate.rcvd.rcvd_pkt, sizeof(dhcp_msg_t));*/
      if (ret < 0) {
        dbg("Packet read error, ignoring. \n");
        return ret; // returns -1
      }
      if (gstate.rcvd.rcvd_pkt.cookie != htonl(DHCP_MAGIC)) {
        dbg("Packet with bad magic, ignoring. \n");
        return -2;
      }
      if (gstate.rcvd.rcvd_pkt.op != 1) { //BOOTPREQUEST
        dbg("Not a BOOT REQUEST ignoring. \n");
        return -2;
      }
      if (gstate.rcvd.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.send_pkt, 0, sizeof(gstate.send.send_pkt));
      gstate.send.send_pkt.op = 2; //BOOTPREPLY
      gstate.send.send_pkt.htype = 1;
      gstate.send.send_pkt.hlen = 6;
      gstate.send.send_pkt.xid = gstate.rcvd.rcvd_pkt.xid;
      gstate.send.send_pkt.cookie = htonl(DHCP_MAGIC);
      gstate.send.send_pkt.nsiaddr = gconfig.server_nip;
      memcpy(gstate.send.send_pkt.chaddr, gstate.rcvd.rcvd_pkt.chaddr, 16);
      gstate.send.send_pkt.options[0] = DHCP_OPT_END;
      return gstate.send.send_pkt.options;
    }
    
    static uint8_t* prepare_send_pkt6(uint16_t opt)
    {
      memset((void*)&gstate.send.send_pkt6, 0, sizeof(gstate.send.send_pkt6));
      gstate.send.send_pkt6.msgtype = opt;
      memcpy(gstate.send.send_pkt6.transaction_id, gstate.rcvd.rcvd_pkt6.transaction_id, 3);
      return gstate.send.send_pkt6.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;
    }
    
    static uint8_t* set_optval6(uint8_t *optptr, uint16_t opt, void *var, size_t len)
    {
      *((uint16_t*)optptr) = htons(opt);
      *(uint16_t*)(optptr+2) = htons(len);
      memcpy(optptr+4, var, len);
      optptr += len+4;
      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.rcvd_pkt.file, opt, var);
      if ((overloaded == 2) | (overloaded == 3)) get_optval((uint8_t*)&gstate.rcvd.rcvd_pkt.sname, opt, var);
      return optptr;
    }
    
    static uint8_t* get_optval6(uint8_t *optptr, uint16_t opt, uint16_t *datalen, void **var)
    {
      uint16_t optcode;
      uint16_t len;
    
      memcpy(&optcode, optptr, sizeof(uint16_t));
      memcpy(&len, optptr+2, sizeof(uint16_t));
      if(!optcode) {
        dbg("Option %d is not exist.\n", opt);
        return optptr;
      }
      optcode = ntohs(optcode);
      len = ntohs(len);
    
      if (opt == optcode) {
        *var = xmalloc(len);
        memcpy(*var, optptr+4, len);
        optptr = optptr + len + 4;
        memcpy(datalen, &len, sizeof(uint16_t));
      }
      else {
        optptr = get_optval6(optptr+len+4, opt, datalen, 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.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 void 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, 0600)) < 0) {
        perror_msg("can't open %s ", gconfig.lease_file);
      } else {
        curr = timestamp = time(NULL);
        timestamp = SWAP_BE64(timestamp);
        writeall(fd, ×tamp, 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);
        }
      }
    }
    
    static void write_lease6file(void)
    {
      int fd;
      uint32_t curr, tmp_time;
      int64_t timestamp;
      struct arg_list *listdls = gstate.dleases;
      dyn_lease6 *dls6;
    
      if ((fd = open(gconfig.lease6_file, O_WRONLY | O_CREAT | O_TRUNC, 0600)) < 0) {
        perror_msg("can't open %s ", gconfig.lease6_file);
      } else {
        curr = timestamp = time(NULL);
        timestamp = SWAP_BE64(timestamp);
        writeall(fd, ×tamp, sizeof(timestamp));
    
        while (listdls) {
          dls6 = (dyn_lease6*)listdls->arg;
          tmp_time = dls6->expires;
          dls6->expires -= curr;
          if ((int32_t) dls6->expires < 0) goto skip;
          dls6->expires = htonl(dls6->expires);
          writeall(fd, dls6, sizeof(dyn_lease6));
    skip:
          dls6->expires = tmp_time;
          listdls = listdls->next;
        }
        close(fd);
        if (gconfig.notify_file) {
          char *argv[3];
          argv[0] = gconfig.notify_file;
          argv[1] = gconfig.lease6_file;
          argv[2] = NULL;
          run_notify(argv);
        }
      }
    }
    
    // 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(addr_version == AF_INET6) {
        if ((req_exp <= 0) || req_exp > gconfig.pref_lifetime ||
            req_exp > gconfig.valid_lifetime) {
          if ((gconfig.pref_lifetime > gconfig.valid_lifetime)) {
            error_msg("The valid lifetime must be greater than the preferred lifetime, \
                setting to valid lifetime %u", gconfig.valid_lifetime);
            return gconfig.valid_lifetime;
          }
          return gconfig.pref_lifetime;
        }
      } else {
        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;
    }
    
    static int verifyip6_in_lease(uint8_t *nip6, uint8_t *duid, uint16_t ia_type, uint32_t iaid)
    {
      static_lease6 *sls6;
      struct arg_list *listdls;
    
      for (listdls = gstate.dleases; listdls; listdls = listdls->next) {
        if (!memcmp(((dyn_lease6*) listdls->arg)->lease_nip6, nip6, sizeof(uint32_t)*4))
          return -1;
    
        if (!memcmp(((dyn_lease6*) listdls->arg)->duid, duid, ((dyn_lease6*) listdls->arg)->duid_len)
            && ((dyn_lease6*) listdls->arg)->ia_type == ia_type) 
          return -1;
      }
      for (sls6 = gstate.leases.sleases6; sls6; sls6 = sls6->next)
        if (memcmp(sls6->nip6, nip6, sizeof(uint32_t)*4)==0) return -2;
    
      if (memcmp(nip6, gconfig.start_ip6, sizeof(uint32_t)*4) < 0 ||
          memcmp(nip6, gconfig.end_ip6, sizeof(uint32_t)*4) > 0)
        return -3;
    
      return 0;
    }
    
    // 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.leases.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;
    }
    
    static int addip6_to_lease(uint8_t *assigned_nip, uint8_t *duid, uint16_t duid_len, uint16_t ia_type, uint32_t iaid, uint32_t *lifetime, uint8_t update)
    {
      dyn_lease6 *dls6;
      struct arg_list *listdls = gstate.dleases;
      uint32_t now = time(NULL);
    
      while (listdls) {
        if (!memcmp(((dyn_lease6*) listdls->arg)->duid, duid, ((dyn_lease6*) listdls->arg)->duid_len)) {
          if (update) *lifetime = get_lease(*lifetime + ((dyn_lease6*) listdls->arg)->expires);
          ((dyn_lease6*) listdls->arg)->expires = *lifetime + now;
          return 0;
        }
        listdls = listdls->next;
      }
    
      dls6 = xzalloc(sizeof(dyn_lease6));
      dls6->duid_len = duid_len; 
      memcpy(dls6->duid, duid, duid_len);
      dls6->ia_type = ia_type;
      dls6->iaid = iaid;
      memcpy(dls6->lease_nip6, assigned_nip, sizeof(uint32_t)*4);
      
      if (update) *lifetime = get_lease(*lifetime + now);
      dls6->expires = *lifetime + now;
    
      listdls = xzalloc(sizeof(struct arg_list));
      listdls->next = gstate.dleases;
      listdls->arg = (char*)dls6;
      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.leases.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 uint8_t *getip6_from_pool(uint8_t *duid, uint16_t duid_len, uint16_t ia_type, uint32_t iaid, uint32_t *lifetime)
    {
      static uint8_t nip6[16] = {0, };
      static_lease6 *sls6 = gstate.leases.sleases6;
      struct arg_list *listdls6 = gstate.dleases, *tmp = NULL;
    
      while(listdls6) {
        if (!memcmp(((dyn_lease6*)listdls6->arg)->duid, duid, duid_len)) {
          memcpy(nip6, ((dyn_lease6*)listdls6->arg)->lease_nip6, sizeof(nip6));
          if(tmp) tmp->next = listdls6->next;
          else gstate.dleases = listdls6->next;
          free(listdls6->arg);
          free(listdls6);
    
          if(verifyip6_in_lease(nip6, duid, ia_type, iaid) < 0)
            memset(nip6, 0, sizeof(nip6));
          break;
        }
        tmp = listdls6;
        listdls6 = listdls6->next;
      }
    
      if(!memcmp(nip6, (uint8_t[16]){0}, sizeof(uint32_t)*4)) {
        while(sls6) {
          if(!memcmp(sls6->duid, duid, 6)) {
            memcpy(nip6, sls6->nip6, sizeof(nip6));
            break;
          }
          sls6 = sls6->next;
        }
      }
    
      if(!memcmp(nip6, (uint8_t[16]){0}, sizeof(uint32_t)*4)) {
        memcpy(nip6, gconfig.start_ip6, sizeof(nip6));
        while(memcmp(nip6, gconfig.end_ip6, sizeof(nip6)) < 0) {
          if(!verifyip6_in_lease(nip6, duid, ia_type, iaid)) break;
          int i=sizeof(nip6);
          while(i--) {
            ++nip6[i];
            if (!nip6[i]) {
              if(i==(sizeof(nip6)-1)) ++nip6[i];
              ++nip6[i-1];
            } else
              break;
          }
        }
    
        if (memcmp(nip6, gconfig.end_ip6, sizeof(nip6)) > 0) {
          memset(nip6, 0, sizeof(nip6));
          infomsg(infomode, "can't find free IP in IPv6 Pool.");
        }
      }
    
      if(memcmp(nip6, (uint8_t[16]){0}, sizeof(uint32_t)*4)) {
        addip6_to_lease(nip6, duid, duid_len, ia_type, iaid, lifetime, 1);
        infomsg(infomode, "Assigned IPv6 %02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X",
            nip6[0], nip6[1], nip6[2], nip6[3], nip6[4], nip6[5], nip6[6], nip6[7], nip6[8],
            nip6[9], nip6[10], nip6[11], nip6[12], nip6[13], nip6[14], nip6[15]);
      }
      return nip6;
    }
    
    static void read_leasefile(void)
    {
      uint32_t passed, ip;
      int32_t tmp_time;
      int64_t timestamp;
      dyn_lease *dls;
      int fd = open(gconfig.lease_file, O_RDONLY);
    
      dls = xzalloc(sizeof(dyn_lease));
    
      if (read(fd, ×tamp, sizeof(timestamp)) != sizeof(timestamp))
        goto lease_error_exit;
    
      timestamp = SWAP_BE64(timestamp);
      passed = time(NULL) - timestamp;
      if ((uint64_t)passed > 12 * 60 * 60) goto lease_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);
        }
      }
    lease_error_exit:
      free(dls);
      close(fd);
    }
    
    static void read_lease6file(void)
    {
      uint32_t passed;
      uint32_t tmp_time;
      int64_t timestamp;
      dyn_lease6 *dls6;
      int fd = open(gconfig.lease6_file, O_RDONLY);
    
      dls6 = xzalloc(sizeof(dyn_lease6));
    
      if (read(fd, ×tamp, sizeof(timestamp)) != sizeof(timestamp))
        goto lease6_error_exit;
    
      timestamp = SWAP_BE64(timestamp);
      passed = time(NULL) - timestamp;
      if ((uint64_t)passed > 12 * 60 * 60) goto lease6_error_exit;
    
      while (read(fd, dls6, sizeof(dyn_lease6)) == sizeof(dyn_lease6)) {
        if (memcmp(dls6->lease_nip6, gconfig.start_ip6, sizeof(uint32_t)*4) > 0 &&
            memcmp(dls6->lease_nip6, gconfig.end_ip6, sizeof(uint32_t)*4) < 0) {
          tmp_time = ntohl(dls6->expires) - passed;
          if (tmp_time < 0U) continue;
          addip6_to_lease(dls6->lease_nip6, dls6->duid, dls6->duid_len, dls6->ia_type, dls6->iaid,
              (uint32_t*)&tmp_time, 0);
        }
      }
    
    lease6_error_exit:
      free(dls6);
      close(fd);
    }
    
    void dhcpd_main(void)
    {
      struct timeval tv;
      int retval, i;
      uint8_t *optptr, msgtype = 0;
      uint16_t optlen = 0;
      uint32_t waited = 0, serverid = 0, requested_nip = 0;
      uint8_t transactionid[3] = {0,};
      uint32_t reqested_lease = 0, ip_pool_size = 0;
      char *hstname = NULL;
      fd_set rfds;
    
      infomode = LOG_CONSOLE;
      if (!(toys.optflags & FLAG_f)) {
        daemon(0,0);
        infomode = LOG_SILENT;
      }
      if (toys.optflags & FLAG_S) {
            openlog("UDHCPD :", LOG_PID, LOG_DAEMON);
            infomode |= LOG_SYSTEM;
      }
      setlinebuf(stdout);
      //DHCPD_CONF_FILE
      parse_server_config((toys.optc==1)?toys.optargs[0]:"/etc/dhcpd.conf", keywords);
      infomsg(infomode, "toybox dhcpd started");
    
      if (toys.optflags & FLAG_6){
        addr_version = AF_INET6;
        gconfig.t1 = ntohl(gconfig.t1);
        gconfig.t2 = ntohl(gconfig.t2);
        gconfig.pref_lifetime = ntohl(gconfig.pref_lifetime);
        gconfig.valid_lifetime = ntohl(gconfig.valid_lifetime);
        gconfig.port = 547;
        for(i=0;i<4;i++)
          ip_pool_size += (gconfig.end_ip6[i]-gconfig.start_ip6[i])<<((3-i)*8);
      } else {
        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();
      if(TT.iface) gconfig.interface = TT.iface;
      if(TT.port) gconfig.port = TT.port;
      (addr_version==AF_INET6) ? read_lease6file() : read_leasefile();
    
    
      if (get_interface(gconfig.interface, &gconfig.ifindex,
            (addr_version==AF_INET6)? (void*)gconfig.server_nip6 :
            (void*)&gconfig.server_nip, gconfig.server_mac) < 0)
        perror_exit("Failed to get interface %s", gconfig.interface);
      setup_signal();
      if (addr_version==AF_INET6) {
        open_listensock6();
      } else {
        gconfig.server_nip = htonl(gconfig.server_nip);
        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;
          (addr_version == AF_INET6)? write_lease6file() : write_leasefile();
          if (get_interface(gconfig.interface, &gconfig.ifindex,
                (addr_version==AF_INET6)? (void*)gconfig.server_nip6 :
                (void*)&gconfig.server_nip, gconfig.server_mac)<0)
            perror_exit("Failed to get interface %s", gconfig.interface);
          if(addr_version != AF_INET6) {
            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");
              (addr_version==AF_INET6)? write_lease6file() : write_leasefile();
              continue;
            case SIGTERM:
              infomsg(infomode, "received sigterm");
              (addr_version==AF_INET6)? write_lease6file() : 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(addr_version==AF_INET6) {
            void *client_duid, *server_duid, *client_ia_na, *server_ia_na,
                 *client_ia_pd;
            uint8_t client_lla[6] = {0,};
            uint16_t client_duid_len = 0, server_duid_len = 0, server_ia_na_len = 0,
                     client_ia_na_len = 0, client_ia_pd_len = 0;
    
            if(read_packet6() < 0) {
              open_listensock6();
              continue;
            }
            waited += time(NULL) - timestmp;
    
            memcpy(&gstate.rqcode, &gstate.rcvd.rcvd_pkt6.msgtype, sizeof(uint8_t));
            memcpy(&transactionid, &gstate.rcvd.rcvd_pkt6.transaction_id,
                sizeof(transactionid));
    
            if (!gstate.rqcode || gstate.rqcode < DHCP6SOLICIT ||
                gstate.rqcode > DHCP6RELAYREPLY) {
              dbg("no or bad message type option, ignoring packet.\n");
              continue;
            }
            if (memcmp(gstate.rcvd.rcvd_pkt6.transaction_id, transactionid, 3)) {
              dbg("no or bad transaction id, ignoring packet.\n");
              continue;
            }
    
            waited += time(NULL) - timestmp;
            switch (gstate.rqcode) {
              case DHCP6SOLICIT:
                dbg("Message Type: DHCP6SOLICIT\n");
                optptr = prepare_send_pkt6(DHCP6ADVERTISE);
                optlen = 0;
    
                //TODO policy check
                //TODO Receive: ORO check (e.g. DNS)
    
                //Receive: Client Identifier (DUID)
                get_optval6((uint8_t*)&gstate.rcvd.rcvd_pkt6.options,
                    DHCP6_OPT_CLIENTID, &client_duid_len, &client_duid);
    
                //Receive: Identity Association for Non-temporary Address
                if(get_optval6((uint8_t*)&gstate.rcvd.rcvd_pkt6.options,
                      DHCP6_OPT_IA_NA, &client_ia_na_len, &client_ia_na)) {
                  uint16_t ia_addr_len = sizeof(struct optval_ia_addr);
                  void *ia_addr, *status_code;
                  char *status_code_msg;
                  uint16_t status_code_len = 0;
                  server_ia_na_len = sizeof(struct optval_ia_na);
    
                  //IA Address
                  ia_addr = xzalloc(ia_addr_len);
                  struct optval_ia_addr *ia_addr_p = (struct optval_ia_addr*)ia_addr;
                  (*ia_addr_p).pref_lifetime = gconfig.pref_lifetime;
                  (*ia_addr_p).valid_lifetime = gconfig.valid_lifetime;
                  memcpy(&(*ia_addr_p).ipv6_addr,
                      getip6_from_pool(client_duid, client_duid_len,
                        DHCP6_OPT_IA_NA, (*(struct optval_ia_na*) client_ia_na).iaid,
                        &(*ia_addr_p).pref_lifetime), sizeof(uint32_t)*4);
                  server_ia_na_len += (ia_addr_len+4);
    
                  //Status Code
                  if(memcmp((*ia_addr_p).ipv6_addr, (uint8_t[16]){0}, sizeof(uint32_t)*4)) {
                    status_code_msg = xstrdup("Assigned an address.");
                    status_code_len = strlen(status_code_msg)+1;
                    status_code = xzalloc(status_code_len);
                    struct optval_status_code *status_code_p =
                      (struct optval_status_code*)status_code;
                    (*status_code_p).status_code = htons(DHCP6_STATUS_SUCCESS);
                    memcpy((*status_code_p).status_msg, status_code_msg,
                        status_code_len);
                    server_ia_na_len += (status_code_len+4);
                    free(status_code_msg);
                  } else {
                    status_code_msg = xstrdup("There's no available address.");
                    status_code_len = strlen(status_code_msg)+1;
                    status_code = xzalloc(status_code_len);
                    struct optval_status_code *status_code_p =
                      (struct optval_status_code*)status_code;
                    (*status_code_p).status_code = htons(DHCP6_STATUS_NOADDRSAVAIL);
                    memcpy((*status_code_p).status_msg, status_code_msg,
                        status_code_len);
                    server_ia_na_len += (status_code_len+4);
                    server_ia_na_len -= (ia_addr_len+4);
                    ia_addr_len = 0;
                    free(ia_addr);
                    free(status_code_msg);
                    //TODO send failed status code
                    break;
                  }
    
                  //combine options
                  server_ia_na = xzalloc(server_ia_na_len);
                  struct optval_ia_na *ia_na_p = (struct optval_ia_na*)server_ia_na;
                  (*ia_na_p).iaid = (*(struct optval_ia_na*)client_ia_na).iaid;
                  (*ia_na_p).t1 = gconfig.t1;
                  (*ia_na_p).t2 = gconfig.t2;
    
                  uint8_t* ia_na_optptr = (*ia_na_p).optval;
                  if(ia_addr_len) {
                    set_optval6(ia_na_optptr, DHCP6_OPT_IA_ADDR, ia_addr, ia_addr_len);
                    ia_na_optptr += (ia_addr_len + 4);
                    free(ia_addr);
                  }
                  if(status_code_len) {
                    set_optval6(ia_na_optptr, DHCP6_OPT_STATUS_CODE, status_code,
                        status_code_len);
                    ia_na_optptr += (status_code_len);
                    free(status_code);
                  }
    
                  //Response: Identity Association for Non-temporary Address
                  optptr = set_optval6(optptr, DHCP6_OPT_IA_NA, server_ia_na,
                      server_ia_na_len);
                  optlen += (server_ia_na_len + 4);
                  free(client_ia_na);free(server_ia_na);
                }
                //Receive: Identity Association for Prefix Delegation
                else if(get_optval6((uint8_t*)&gstate.rcvd.rcvd_pkt6.options,
                      DHCP6_OPT_IA_PD, &client_ia_pd_len, &client_ia_pd)) {
    
                  //TODO
                  //Response: Identity Association for Prefix Delegation
                }
    
                //DUID type: link-layer address plus time
                if(ntohs((*(struct optval_duid_llt*)client_duid).type) ==
                    DHCP6_DUID_LLT) {
                  server_duid_len = 8+sizeof(gconfig.server_mac);
                  server_duid = xzalloc(server_duid_len);
                  struct optval_duid_llt *server_duid_p =
                    (struct optval_duid_llt*)server_duid;
                  (*server_duid_p).type = htons(1);
                  (*server_duid_p).hwtype = htons(1);
                  (*server_duid_p).time = htonl((uint32_t)
                      (time(NULL) - 946684800) & 0xffffffff);
                  memcpy((*server_duid_p).lladdr, gconfig.server_mac,
                      sizeof(gconfig.server_mac));
                  memcpy(&client_lla, (*(struct optval_duid_llt*)client_duid).lladdr,
                      sizeof(client_lla));
    
                  //Response: Server Identifier (DUID)
                  optptr = set_optval6(optptr, DHCP6_OPT_SERVERID, server_duid,
                      server_duid_len);
                  optlen += (server_duid_len + 4);
                  //Response: Client Identifier
                  optptr = set_optval6(optptr, DHCP6_OPT_CLIENTID, client_duid,
                      client_duid_len);
                  optlen += (client_duid_len + 4);
                  free(client_duid);free(server_duid);
                }
    
                send_packet6(0, client_lla, optlen);
                write_lease6file();
                break;
              case DHCP6REQUEST:
                dbg("Message Type: DHCP6REQUEST\n");
                optptr = prepare_send_pkt6(DHCP6REPLY);
                optlen = 0;
    
                //Receive: Client Identifier (DUID)
                get_optval6((uint8_t*)&gstate.rcvd.rcvd_pkt6.options,
                    DHCP6_OPT_CLIENTID, &client_duid_len, &client_duid);
                optptr = set_optval6(optptr, DHCP6_OPT_CLIENTID, client_duid,
                    client_duid_len);
                optlen += (client_duid_len + 4);
                memcpy(client_lla, (*(struct optval_duid_llt*)client_duid).lladdr,
                    sizeof(client_lla));
    
                //Receive: Identity Association for Non-temporary Address
                if(get_optval6((uint8_t*)&gstate.rcvd.rcvd_pkt6.options,
                      DHCP6_OPT_IA_NA, &client_ia_na_len, &client_ia_na)) {
                  uint16_t ia_addr_len = 0, status_code_len = 0;
                  void *ia_addr, *status_code;
                  uint16_t server_ia_na_len = sizeof(struct optval_ia_na);
                  char *status_code_msg;
    
                  //Check IA Address
                  get_optval6((uint8_t*)(*(struct optval_ia_na*)client_ia_na).optval,
                      DHCP6_OPT_IA_ADDR, &ia_addr_len, &ia_addr);
                  struct optval_ia_addr *ia_addr_p = (struct optval_ia_addr*)ia_addr;
                  if(verifyip6_in_lease((*ia_addr_p).ipv6_addr, client_duid,
                        DHCP6_OPT_IA_NA, (*(struct optval_ia_na*)client_ia_na).iaid)
                      == -1) {
                    server_ia_na_len += (ia_addr_len + 4);
                    //Add Status Code
                    status_code_msg = xstrdup("Assigned an address.");
                    status_code_len = strlen(status_code_msg) + 1;
                    status_code = xzalloc(status_code_len);
                    struct optval_status_code *status_code_p =
                      (struct optval_status_code*)status_code;
                    (*status_code_p).status_code = htons(DHCP6_STATUS_SUCCESS);
                    memcpy((*status_code_p).status_msg, status_code_msg,
                        status_code_len);
                    server_ia_na_len += (status_code_len+4);
                  } else {
                    //TODO send failed status code
                    break;
                  }
    
                  //combine options
                  server_ia_na = xzalloc(server_ia_na_len);
                  struct optval_ia_na *ia_na_p = (struct optval_ia_na*)server_ia_na;
                  (*ia_na_p).iaid = (*(struct optval_ia_na*)client_ia_na).iaid;
                  (*ia_na_p).t1 = gconfig.t1;
                  (*ia_na_p).t2 = gconfig.t2;
    
                  uint8_t* ia_na_optptr = (*ia_na_p).optval;
                  ia_na_optptr = set_optval6(ia_na_optptr, DHCP6_OPT_IA_ADDR,
                      ia_addr, ia_addr_len);
                  free(ia_addr);
    
                  if(status_code_len) {
                    ia_na_optptr = set_optval6(ia_na_optptr, DHCP6_OPT_STATUS_CODE,
                        status_code, status_code_len);
                    free(status_code);
                  }
    
                  //Response: Identity Association for Non-temporary Address
                  //(Status Code added)
                  optptr = set_optval6(optptr, DHCP6_OPT_IA_NA,
                      server_ia_na, server_ia_na_len);
                  optlen += (server_ia_na_len + 4);
                  free(client_ia_na);free(server_ia_na);
                }
    
                //Receive: Server Identifier (DUID)
                get_optval6((uint8_t*)&gstate.rcvd.rcvd_pkt6.options,
                    DHCP6_OPT_SERVERID, &server_duid_len, &server_duid);
                optptr = set_optval6(optptr, DHCP6_OPT_SERVERID,
                    server_duid, server_duid_len);
                optlen += (server_duid_len + 4);
    
                free(client_duid); free(server_duid);
    
                send_packet6(0, client_lla, optlen);
                write_lease6file();
                break;
              case DHCP6DECLINE:  //TODO
              case DHCP6RENEW:    //TODO
              case DHCP6REBIND:   //TODO
              case DHCP6RELEASE:
                dbg("Message Type: DHCP6RELEASE\n");
                optptr = prepare_send_pkt6(DHCP6REPLY);
                break;
              default:
                dbg("Message Type : %u\n", gstate.rqcode);
                break;
            }
            
          } else {
            if(read_packet() < 0) {
              open_listensock();
              continue;
            }
            waited += time(NULL) - timestmp;
    
            get_optval((uint8_t*)&gstate.rcvd.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.rcvd_pkt.options,
                DHCP_OPT_SERVER_ID, &serverid);
            if (serverid && (serverid != gconfig.server_nip)) {
              dbg("server ID doesn't match, ignoring packet.\n");
              continue;
            }
    
            waited += time(NULL) - timestmp;
            switch (gstate.rqcode) {
              case DHCPDISCOVER:
                msgtype = DHCPOFFER;
                dbg("Message Type : DHCPDISCOVER\n");
                get_optval((uint8_t*) &gstate.rcvd.rcvd_pkt.options,
                    DHCP_OPT_REQUESTED_IP, &requested_nip);
                get_optval((uint8_t*) &gstate.rcvd.rcvd_pkt.options,
                    DHCP_OPT_HOST_NAME, &hs