toys/pending/dhcp6.c - third_party/toybox - Git at Google

 /* dhcp6.c - DHCP6 client for dynamic network configuration.
  *
  * Copyright 2015 Rajni Kant <rajnikant12345@gmail.com>
  *
  * Not in SUSv4.
 USE_DHCP6(NEWTOY(dhcp6, "r:A#<0T#<0t#<0s:p:i:SRvqnbf", TOYFLAG_SBIN|TOYFLAG_ROOTONLY))

 config DHCP6
   bool "dhcp6"
   default n
   help
   usage: dhcp6 [-fbnqvR] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]

         Configure network dynamicaly using DHCP.

       -i Interface to use (default eth0)
       -p Create pidfile
       -s Run PROG at DHCP events
       -t Send up to N Solicit packets
       -T Pause between packets (default 3 seconds)
       -A Wait N seconds after failure (default 20)
       -f Run in foreground
       -b Background if lease is not obtained
       -n Exit if lease is not obtained
       -q Exit after obtaining lease
       -R Release IP on exit
       -S Log to syslog too
       -r Request this IP address
       -v Verbose

       Signals:
       USR1  Renew current lease
       USR2  Release current lease
 */
 #define FOR_dhcp6
 #include "toys.h"
 #include <linux/sockios.h>
 #include <linux/if_ether.h>
 #include <netinet/ip.h>
 #include <netinet/ip6.h>
 #include <netinet/udp.h>
 #include <linux/if_packet.h>
 #include <syslog.h>

 GLOBALS(
   char *interface_name, *pidfile, *script;
   long retry, timeout, errortimeout;
   char *req_ip;
   int length, state, request_length, sock, sock1, status, retval, retries;
   struct timeval tv;
   uint8_t transction_id[3];
   struct sockaddr_in6 input_socket6;
 )

 #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

 // 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

 #define DHCPC_SERVER_PORT     547
 #define DHCPC_CLIENT_PORT     546

 #define LOG_SILENT          0x0
 #define LOG_CONSOLE         0x1
 #define LOG_SYSTEM          0x2

 typedef struct __attribute__((packed)) dhcp6_msg_s {
   uint8_t msgtype, transaction_id[3], options[524];
 } dhcp6_msg_t;

 typedef struct __attribute__((packed)) optval_duid_llt {
   uint16_t type;
   uint16_t hwtype;
   uint32_t time;
   uint8_t lladdr[6];
 } DUID;

 typedef struct __attribute__((packed)) optval_ia_na {
   uint32_t iaid, t1, t2;
 } IA_NA;

 typedef struct __attribute__((packed)) dhcp6_raw_s {
   struct ip6_hdr iph;
   struct udphdr udph;
   dhcp6_msg_t dhcp6;
 } dhcp6_raw_t;

 typedef struct __attribute__((packed)) dhcp_data_client {
   uint16_t  status_code;
   uint32_t iaid , t1,t2, pf_lf, va_lf;
   uint8_t ipaddr[17] ;
 } DHCP_DATA;

 static DHCP_DATA dhcp_data;
 static dhcp6_raw_t *mymsg;
 static dhcp6_msg_t mesg;
 static DUID *duid;

 static void (*dbg)(char *format, ...);
 static void dummy(char *format, ...)
 {
   return;
 }

 static void logit(char *format, ...)
 {
   int used;
   char *msg;
   va_list p, t;
   uint8_t infomode = LOG_SILENT;

   if (toys.optflags & FLAG_S) infomode |= LOG_SYSTEM;
   if(toys.optflags & FLAG_v) infomode |= LOG_CONSOLE;
   va_start(p, format);
   va_copy(t, p);
   used = vsnprintf(NULL, 0, format, t);
   used++;
   va_end(t);

   msg = xmalloc(used);
   vsnprintf(msg, used, format, p);
   va_end(p);

   if (infomode & LOG_SYSTEM) syslog(LOG_INFO, "%s", msg);
   if (infomode & LOG_CONSOLE) printf("%s", msg);
   free(msg);
   return;
 }

 static void get_mac(uint8_t *mac, char *interface)
 {
   int fd;
   struct ifreq req;

   if (!mac) return;
   fd = xsocket(AF_INET6, SOCK_RAW, IPPROTO_RAW);
   req.ifr_addr.sa_family = AF_INET6;
   xstrncpy(req.ifr_name, interface, IFNAMSIZ);
   xioctl(fd, SIOCGIFHWADDR, &req);
   memcpy(mac, req.ifr_hwaddr.sa_data, 6);
   xclose(fd);
 }

 static void fill_option(uint16_t option_id, uint16_t option_len, uint8_t **dhmesg)
 {
   uint8_t *tmp = *dhmesg;

   *((uint16_t*)tmp) = htons(option_id);
   *(uint16_t*)(tmp+2) = htons(option_len);
   *dhmesg += 4;
   TT.length += 4;
 }

 static void fill_clientID()
 {
   uint8_t *tmp = &mesg.options[TT.length];

   if(!duid) {
     uint8_t mac[7] = {0,};
     duid = (DUID*)malloc(sizeof(DUID));
     duid->type = htons(1);
     duid->hwtype = htons(1);
     duid->time = htonl((uint32_t)(time(NULL) - 946684800) & 0xffffffff);
     fill_option(DHCP6_OPT_CLIENTID,14,&tmp);
     get_mac(mac, TT.interface_name);
     memcpy(duid->lladdr,mac, 6);
     memcpy(tmp,(uint8_t*)duid,sizeof(DUID));
   }
   else {
     fill_option(DHCP6_OPT_CLIENTID,14,&tmp);
     memcpy(tmp,(uint8_t*)duid,sizeof(DUID));
   }
   TT.length += sizeof(DUID);
 }

 // TODO: make it generic for multiple options.
 static void fill_optionRequest()
 {
   uint8_t *tmp = &mesg.options[TT.length];

   fill_option(DHCP6_OPT_ORO,4,&tmp);
   *(uint16_t*)(tmp+4) = htons(23);
   *(uint16_t*)(tmp+6) = htons(24);
   TT.length += 4;
 }

 static void fill_elapsedTime()
 {
   uint8_t *tmp = &mesg.options[TT.length];

   fill_option(DHCP6_OPT_ELAPSED_TIME, 2, &tmp);
   *(uint16_t*)(tmp+6) = htons(0);
   TT.length += 2;
 }

 static void fill_iaid()
 {
   IA_NA iana;
   uint8_t *tmp = &mesg.options[TT.length];

   fill_option(DHCP6_OPT_IA_NA, 12, &tmp);
   iana.iaid = rand();
   iana.t1 = 0xffffffff;
   iana.t2 = 0xffffffff;
   memcpy(tmp, (uint8_t*)&iana, sizeof(IA_NA));
   TT.length += sizeof(IA_NA);
 }

 //static void mode_raw(int *sock_t)
 static void mode_raw()
 {
   int constone = 1;
   struct sockaddr_ll sockll;

   if (TT.sock > 0) xclose(TT.sock);
   TT.sock = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IPV6));

   memset(&sockll, 0, sizeof(sockll));
   sockll.sll_family = AF_PACKET;
   sockll.sll_protocol = htons(ETH_P_IPV6);
   sockll.sll_ifindex = if_nametoindex(TT.interface_name);
   if (bind(TT.sock, (struct sockaddr *) &sockll, sizeof(sockll))) {
     xclose(TT.sock);
     error_exit("MODE RAW : Bind fail.\n");
   }
   if (setsockopt(TT.sock, SOL_PACKET, PACKET_HOST,&constone, sizeof(int)) < 0) {
 		if (errno != ENOPROTOOPT) error_exit("MODE RAW : Bind fail.\n");
 	}
 }

 static void generate_transection_id()
 {
   int i, r = rand() % 0xffffff;

   for (i=0; i<3; i++) {
     TT.transction_id[i] = r%0xff;
     r = r/10;
   }
 }

 static void set_timeout(int seconds)
 {
   TT.tv.tv_sec = seconds;
   TT.tv.tv_usec = 100000;
 }

 static void  send_msg(int type)
 {
   struct sockaddr_in6 addr6;
   int sendlength = 0;

   memset(&addr6, 0, sizeof(addr6));
   addr6.sin6_family = AF_INET6;
   addr6.sin6_port = htons(DHCPC_SERVER_PORT); //SERVER_PORT
   inet_pton(AF_INET6, "ff02::1:2", &addr6.sin6_addr);
   mesg.msgtype = type;
   generate_transection_id();
   memcpy(mesg.transaction_id, TT.transction_id, 3);

   if (type  == DHCP6SOLICIT) {
     TT.length = 0;
     fill_clientID();
     fill_optionRequest();
     fill_elapsedTime();
     fill_iaid();
     sendlength = sizeof(dhcp6_msg_t) - 524 + TT.length;
   } else if (type == DHCP6REQUEST || type == DHCP6RELEASE || type == DHCP6RENEW)
     sendlength = TT.request_length;
   dbg("Sending message type: %d\n", type);
   sendlength = sendto(TT.sock1, &mesg, sendlength , 0,(struct sockaddr *)&addr6,
           sizeof(struct sockaddr_in6 ));
   if (sendlength <= 0) dbg("Error in sending message type: %d\n", type);
 }

 uint8_t *get_msg_ptr(uint8_t *data, int data_length, int msgtype)
 {
   uint16_t type =  *((uint16_t*)data), length = *((uint16_t*)(data+2));

   type = ntohs(type);
   if (type == msgtype) return data;
   length = ntohs(length);
   while (type != msgtype) {
     data_length -= (4 + length);
     if (data_length <= 0) break;
     data = data + 4 + length;
     type = ntohs(*((uint16_t*)data));
     length = ntohs(*((uint16_t*)(data+2)));
     if (type == msgtype) return data;
   }
   return NULL;
 }

 static uint8_t *check_server_id(uint8_t *data, int data_length)
 {
   return get_msg_ptr(data,  data_length, DHCP6_OPT_SERVERID);
 }

 static int check_client_id(uint8_t *data, int data_length)
 {
   if ((data = get_msg_ptr(data,  data_length, DHCP6_OPT_CLIENTID))) {
     DUID one = *((DUID*)(data+4));
     DUID two = *((DUID*)&mesg.options[4]);

     if (!memcmp(&one, &two, sizeof(DUID))) return 1;
   }
   return 0;
 }

 static int validate_ids()
 {
   if (!check_server_id(mymsg->dhcp6.options,
     TT.status - ((char*)&mymsg->dhcp6.options[0] - (char*)mymsg) )) {
     dbg("Invalid server id: %d\n");
     return 0;
   }
   if (!check_client_id(mymsg->dhcp6.options,
     TT.status - ((char*)&mymsg->dhcp6.options[0] - (char*)mymsg) )) {
     dbg("Invalid client id: %d\n");
     return 0;
   }
   return 1;
 }

 static void parse_ia_na(uint8_t *data, int data_length)
 {
   uint8_t *t = get_msg_ptr(data, data_length, DHCP6_OPT_IA_NA);
   uint16_t iana_len, content_len = 0;

   memset(&dhcp_data,0,sizeof(dhcp_data));
   if (!t) return;

   iana_len = ntohs(*((uint16_t*)(t+2)));
   dhcp_data.iaid = ntohl(*((uint32_t*)(t+4)));
   dhcp_data.t1 = ntohl(*((uint32_t*)(t+8)));
   dhcp_data.t2 = ntohl(*((uint32_t*)(t+12)));
   t += 16;
   iana_len -= 12;

   while(iana_len > 0) {
     uint16_t sub_type = ntohs(*((uint16_t*)(t)));

     switch (sub_type) {
       case DHCP6_OPT_IA_ADDR:
         content_len = ntohs(*((uint16_t*)(t+2)));
         memcpy(dhcp_data.ipaddr,t+4,16);
         if (TT.state == DHCP6SOLICIT) {
           if (TT.req_ip) {
             struct addrinfo *res = NULL;

             if(!getaddrinfo(TT.req_ip, NULL, NULL,&res)) {
               dbg("Requesting IP: %s\n", TT.req_ip);
               memcpy (&TT.input_socket6, res->ai_addr, res->ai_addrlen);
               memcpy(t+4, TT.input_socket6.sin6_addr.__in6_u.__u6_addr8, 16);
             } else xprintf("Invalid IP: %s\n",TT.req_ip);
             freeaddrinfo(res);
           }
         }
         dhcp_data.pf_lf = ntohl(*((uint32_t*)(t+20)));
         dhcp_data.va_lf = ntohl(*((uint32_t*)(t+24)));
         iana_len -= (content_len + 4);
         t += (content_len + 4);
         break;
       case DHCP6_OPT_STATUS_CODE:
         content_len = ntohs(*((uint16_t*)(t+2)));
         dhcp_data.status_code = ntohs(*((uint16_t*)(t+4)));
         iana_len -= (content_len + 4);
         t += (content_len + 4);
         break;
       default:
         content_len = ntohs(*((uint16_t*)(t+2)));
         iana_len -= (content_len + 4);
         t += (content_len + 4);
         break;
     }
   }
 }

 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);
   }
 }

 // Creates environment pointers from RES to use in script
 static int fill_envp(DHCP_DATA *res)
 {
   int ret = setenv("interface", TT.interface_name, 1);

   if (ret) return ret;
   inet_ntop(AF_INET6, res->ipaddr, toybuf, INET6_ADDRSTRLEN);
   ret = setenv("ip",(const char*)toybuf , 1);
   return ret;
 }

 // Executes Script NAME.
 static void run_script(DHCP_DATA *res,  char *name)
 {
   volatile int error = 0;
   struct stat sts;
   pid_t pid;
   char *argv[3];
   char *script = (toys.optflags & FLAG_s) ? TT.script
     : "/usr/share/dhcp/default.script";

   if (stat(script, &sts) == -1 && errno == ENOENT) return;
   if (!res || fill_envp(res)) {
     dbg("Failed to create environment variables.\n");
     return;
   }
   dbg("Executing %s %s\n", script, name);
   argv[0] = (char*)script;
   argv[1] = (char*)name;
   argv[2] = NULL;
   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;
     perror_msg("script exec failed");
   }
   dbg("script complete.\n");
 }

 static void lease_fail()
 {
   dbg("Lease failed.\n");
   run_script(NULL, "leasefail");
   if (toys.optflags & FLAG_n) {
     xclose(TT.sock);
     xclose(TT.sock1);
     error_exit("Lease Failed, Exiting.");
   }
   if (toys.optflags & FLAG_b) {
     dbg("Lease failed. Going to daemon mode.\n");
     if (daemon(0,0)) perror_exit("daemonize");
     if (toys.optflags & FLAG_p) write_pid(TT.pidfile);
     toys.optflags &= ~FLAG_b;
     toys.optflags |= FLAG_f;
   }
 }

 // Generic signal handler real handling is done in main funcrion.
 static void signal_handler(int sig)
 {
     dbg("Caught signal: %d\n", sig);
     switch (sig) {
     case SIGUSR1:
       dbg("SIGUSR1.\n");
       if (TT.state == DHCP6RELEASE || TT.state == DHCP6REQUEST ) {
         TT.state = DHCP6SOLICIT;
         set_timeout(0);
         return;
       }
       dbg("SIGUSR1 sending renew.\n");
       send_msg(DHCP6RENEW);
       TT.state = DHCP6RENEW;
       TT.retries = 0;
       set_timeout(0);
       break;
     case SIGUSR2:
       dbg("SIGUSR2.\n");
       if (TT.state == DHCP6RELEASE) return;
       if (TT.state != DHCP6CONFIRM ) return;
       dbg("SIGUSR2 sending release.\n");
       send_msg(DHCP6RELEASE);
       TT.state = DHCP6RELEASE;
       TT.retries = 0;
       set_timeout(0);
       break;
     case SIGTERM:
     case SIGINT:
       dbg((sig == SIGTERM)?"SIGTERM.\n":"SIGINT.\n");
       if ((toys.optflags & FLAG_R) && TT.state == DHCP6CONFIRM)
         send_msg(DHCP6RELEASE);
       if(sig == SIGINT) exit(0);
       break;
     default: break;
   }
 }

 // signal setup for SIGUSR1 SIGUSR2 SIGTERM
 static int setup_signal()
 {
   signal(SIGUSR1, signal_handler);
   signal(SIGUSR2, signal_handler);
   signal(SIGTERM, signal_handler);
   signal(SIGINT, signal_handler);
   return 0;
 }

 void dhcp6_main(void)
 {
   struct sockaddr_in6  sinaddr6;
   int constone = 1;
   fd_set rfds;

   srand(time(NULL));
   setlinebuf(stdout);
   dbg = dummy;
   TT.state = DHCP6SOLICIT;

   if (toys.optflags & FLAG_v) dbg = logit;
   if (!TT.interface_name) TT.interface_name = "eth0";
   if (toys.optflags & FLAG_p) write_pid(TT.pidfile);
   if (!TT.retry) TT.retry = 3;
   if (!TT.timeout) TT.timeout = 3;
   if (!TT.errortimeout) TT.errortimeout = 20;
   if (toys.optflags & FLAG_S) {
     openlog("DHCP6 :", LOG_PID, LOG_DAEMON);
     dbg = logit;
   }

   dbg("Interface: %s\n", TT.interface_name);
   dbg("pid file: %s\n", TT.pidfile);
   dbg("Retry count: %d\n", TT.retry);
   dbg("Timeout : %d\n", TT.timeout);
   dbg("Error timeout: %d\n", TT.errortimeout);


   setup_signal();
   TT.sock1 = xsocket(PF_INET6, SOCK_DGRAM, 0);
   memset(&sinaddr6, 0, sizeof(sinaddr6));
   sinaddr6.sin6_family = AF_INET6;
   sinaddr6.sin6_port = htons(DHCPC_CLIENT_PORT);
   sinaddr6.sin6_scope_id = if_nametoindex(TT.interface_name);
   sinaddr6.sin6_addr = in6addr_any ;

   xsetsockopt(TT.sock1, SOL_SOCKET, SO_REUSEADDR, &constone, sizeof(constone));

   if (bind(TT.sock1, (struct sockaddr *)&sinaddr6, sizeof(sinaddr6))) {
     xclose(TT.sock1);
     error_exit("bind failed");
   }

   mode_raw();
   set_timeout(0);
   for (;;) {
     int maxfd = TT.sock;

     if (TT.sock >= 0) FD_SET(TT.sock, &rfds);
     TT.retval = 0;
     if ((TT.retval = select(maxfd + 1, &rfds, NULL, NULL, &TT.tv)) < 0) {
       if(errno == EINTR) continue;
       perror_exit("Error in select");
     }
     if (!TT.retval) {
       if (TT.state == DHCP6SOLICIT || TT.state == DHCP6CONFIRM) {
         dbg("State is solicit, sending solicit packet\n");
         run_script(NULL, "deconfig");
         send_msg(DHCP6SOLICIT);
         TT.state = DHCP6SOLICIT;
         TT.retries++;
         if(TT.retries > TT.retry) set_timeout(TT.errortimeout);
         else if (TT.retries == TT.retry) {
           dbg("State is solicit, retry count is max.\n");
           lease_fail();
           set_timeout(TT.errortimeout);
         } else set_timeout(TT.timeout);
         continue;
       } else if (TT.state == DHCP6REQUEST || TT.state == DHCP6RENEW ||
               TT.state == DHCP6RELEASE) {
         dbg("State is %d , sending packet\n", TT.state);
         send_msg(TT.state);
         TT.retries++;
         if (TT.retries > TT.retry) set_timeout(TT.errortimeout);
         else if (TT.retries == TT.retry) {
           lease_fail();
           set_timeout(TT.errortimeout);
         } else set_timeout(TT.timeout);
         continue;
       }
     } else if (FD_ISSET(TT.sock, &rfds)) {
       if ((TT.status = read(TT.sock, toybuf, sizeof(toybuf))) <= 0) continue;
       mymsg = (dhcp6_raw_t*)toybuf;
       if (ntohs(mymsg->udph.dest) == 546 &&
               !memcmp(mymsg->dhcp6.transaction_id, TT.transction_id, 3)) {
         if (TT.state == DHCP6SOLICIT) {
           if (mymsg->dhcp6.msgtype == DHCP6ADVERTISE ) {
             if (!validate_ids()) {
               dbg("Invalid id recieved, solicit.\n");
               TT.state = DHCP6SOLICIT;
               continue;
             }
             dbg("Got reply to request or solicit.\n");
             TT.retries = 0;
             set_timeout(0);
             TT.request_length = TT.status - ((char*)&mymsg->dhcp6 - (char*)mymsg);
             memcpy((uint8_t*)&mesg, &mymsg->dhcp6, TT.request_length);
             parse_ia_na(mesg.options, TT.request_length);
             dbg("Status code:%d\n", dhcp_data.status_code);
             inet_ntop(AF_INET6, dhcp_data.ipaddr, toybuf, INET6_ADDRSTRLEN);
             dbg("Advertiesed IP: %s\n", toybuf);
             TT.state = DHCP6REQUEST;
           } else {
             dbg("Invalid solicit.\n");
             continue;
           }
         } else if (TT.state == DHCP6REQUEST || TT.state == DHCP6RENEW ) {
           if (mymsg->dhcp6.msgtype == DHCP6REPLY) {
             if (!validate_ids()) {
               dbg("Invalid id recieved, %d.\n", TT.state);
               TT.state = DHCP6REQUEST;
               continue;
             }
             dbg("Got reply to request or renew.\n");
             TT.request_length = TT.status - ((char*)&mymsg->dhcp6 - (char*)mymsg);
             memcpy((uint8_t*)&mesg, &mymsg->dhcp6, TT.request_length);
             parse_ia_na(mymsg->dhcp6.options, TT.request_length);
             dbg("Status code:%d\n", dhcp_data.status_code);
             inet_ntop(AF_INET6, dhcp_data.ipaddr, toybuf, INET6_ADDRSTRLEN);
             dbg("Got IP: %s\n", toybuf);
             TT.retries = 0;
             run_script(&dhcp_data, (TT.state == DHCP6REQUEST) ?
               "request" : "renew");
             if (toys.optflags & FLAG_q) {
               if (toys.optflags & FLAG_R) send_msg(DHCP6RELEASE);
               break;
             }
             TT.state = DHCP6CONFIRM;
             set_timeout((dhcp_data.va_lf)?dhcp_data.va_lf:INT_MAX);
             dbg("Setting timeout to intmax.");
             if (TT.state == DHCP6REQUEST || !(toys.optflags & FLAG_f)) {
               dbg("Making it a daemon\n");
               if (daemon(0,0)) perror_exit("daemonize");
               toys.optflags |= FLAG_f;
               if (toys.optflags & FLAG_p) write_pid(TT.pidfile);
             }
             dbg("Making it a foreground.\n");
             continue;
           } else {
             dbg("Invalid reply.\n");
             continue;
           }
         } else if (TT.state == DHCP6RELEASE) {
           dbg("Got reply to release.\n");
           run_script(NULL, "release");
           set_timeout(INT_MAX);
         }
       }
     }
   }
   xclose(TT.sock1);
   xclose(TT.sock);
 }
	/* dhcp6.c - DHCP6 client for dynamic network configuration.
	*
	* Copyright 2015 Rajni Kant <rajnikant12345@gmail.com>
	*
	* Not in SUSv4.
	USE_DHCP6(NEWTOY(dhcp6, "r:A#<0T#<0t#<0s:p:i:SRvqnbf", TOYFLAG_SBIN\|TOYFLAG_ROOTONLY))

	config DHCP6
	bool "dhcp6"
	default n
	help
	usage: dhcp6 [-fbnqvR] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]

	Configure network dynamicaly using DHCP.

	-i Interface to use (default eth0)
	-p Create pidfile
	-s Run PROG at DHCP events
	-t Send up to N Solicit packets
	-T Pause between packets (default 3 seconds)
	-A Wait N seconds after failure (default 20)
	-f Run in foreground
	-b Background if lease is not obtained
	-n Exit if lease is not obtained
	-q Exit after obtaining lease
	-R Release IP on exit
	-S Log to syslog too
	-r Request this IP address
	-v Verbose

	Signals:
	USR1 Renew current lease
	USR2 Release current lease
	*/
	#define FOR_dhcp6
	#include "toys.h"
	#include <linux/sockios.h>
	#include <linux/if_ether.h>
	#include <netinet/ip.h>
	#include <netinet/ip6.h>
	#include <netinet/udp.h>
	#include <linux/if_packet.h>
	#include <syslog.h>

	GLOBALS(
	char interface_name, pidfile, *script;
	long retry, timeout, errortimeout;
	char *req_ip;
	int length, state, request_length, sock, sock1, status, retval, retries;
	struct timeval tv;
	uint8_t transction_id[3];
	struct sockaddr_in6 input_socket6;
	)

	#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

	// 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

	#define DHCPC_SERVER_PORT 547
	#define DHCPC_CLIENT_PORT 546

	#define LOG_SILENT 0x0
	#define LOG_CONSOLE 0x1
	#define LOG_SYSTEM 0x2

	typedef struct __attribute__((packed)) dhcp6_msg_s {
	uint8_t msgtype, transaction_id[3], options[524];
	} dhcp6_msg_t;

	typedef struct __attribute__((packed)) optval_duid_llt {
	uint16_t type;
	uint16_t hwtype;
	uint32_t time;
	uint8_t lladdr[6];
	} DUID;

	typedef struct __attribute__((packed)) optval_ia_na {
	uint32_t iaid, t1, t2;
	} IA_NA;

	typedef struct __attribute__((packed)) dhcp6_raw_s {
	struct ip6_hdr iph;
	struct udphdr udph;
	dhcp6_msg_t dhcp6;
	} dhcp6_raw_t;

	typedef struct __attribute__((packed)) dhcp_data_client {
	uint16_t status_code;
	uint32_t iaid , t1,t2, pf_lf, va_lf;
	uint8_t ipaddr[17] ;
	} DHCP_DATA;

	static DHCP_DATA dhcp_data;
	static dhcp6_raw_t *mymsg;
	static dhcp6_msg_t mesg;
	static DUID *duid;

	static void (dbg)(char format, ...);
	static void dummy(char *format, ...)
	{
	return;
	}

	static void logit(char *format, ...)
	{
	int used;
	char *msg;
	va_list p, t;
	uint8_t infomode = LOG_SILENT;

	if (toys.optflags & FLAG_S) infomode \|= LOG_SYSTEM;
	if(toys.optflags & FLAG_v) infomode \|= LOG_CONSOLE;
	va_start(p, format);
	va_copy(t, p);
	used = vsnprintf(NULL, 0, format, t);
	used++;
	va_end(t);

	msg = xmalloc(used);
	vsnprintf(msg, used, format, p);
	va_end(p);

	if (infomode & LOG_SYSTEM) syslog(LOG_INFO, "%s", msg);
	if (infomode & LOG_CONSOLE) printf("%s", msg);
	free(msg);
	return;
	}

	static void get_mac(uint8_t mac, char interface)
	{
	int fd;
	struct ifreq req;

	if (!mac) return;
	fd = xsocket(AF_INET6, SOCK_RAW, IPPROTO_RAW);
	req.ifr_addr.sa_family = AF_INET6;
	xstrncpy(req.ifr_name, interface, IFNAMSIZ);
	xioctl(fd, SIOCGIFHWADDR, &req);
	memcpy(mac, req.ifr_hwaddr.sa_data, 6);
	xclose(fd);
	}

	static void fill_option(uint16_t option_id, uint16_t option_len, uint8_t **dhmesg)
	{
	uint8_t tmp = dhmesg;

	((uint16_t)tmp) = htons(option_id);
	(uint16_t)(tmp+2) = htons(option_len);
	*dhmesg += 4;
	TT.length += 4;
	}

	static void fill_clientID()
	{
	uint8_t *tmp = &mesg.options[TT.length];

	if(!duid) {
	uint8_t mac[7] = {0,};
	duid = (DUID*)malloc(sizeof(DUID));
	duid->type = htons(1);
	duid->hwtype = htons(1);
	duid->time = htonl((uint32_t)(time(NULL) - 946684800) & 0xffffffff);
	fill_option(DHCP6_OPT_CLIENTID,14,&tmp);
	get_mac(mac, TT.interface_name);
	memcpy(duid->lladdr,mac, 6);
	memcpy(tmp,(uint8_t*)duid,sizeof(DUID));
	}
	else {
	fill_option(DHCP6_OPT_CLIENTID,14,&tmp);
	memcpy(tmp,(uint8_t*)duid,sizeof(DUID));
	}
	TT.length += sizeof(DUID);
	}

	// TODO: make it generic for multiple options.
	static void fill_optionRequest()
	{
	uint8_t *tmp = &mesg.options[TT.length];

	fill_option(DHCP6_OPT_ORO,4,&tmp);
	(uint16_t)(tmp+4) = htons(23);
	(uint16_t)(tmp+6) = htons(24);
	TT.length += 4;
	}

	static void fill_elapsedTime()
	{
	uint8_t *tmp = &mesg.options[TT.length];

	fill_option(DHCP6_OPT_ELAPSED_TIME, 2, &tmp);
	(uint16_t)(tmp+6) = htons(0);
	TT.length += 2;
	}

	static void fill_iaid()
	{
	IA_NA iana;
	uint8_t *tmp = &mesg.options[TT.length];

	fill_option(DHCP6_OPT_IA_NA, 12, &tmp);
	iana.iaid = rand();
	iana.t1 = 0xffffffff;
	iana.t2 = 0xffffffff;
	memcpy(tmp, (uint8_t*)&iana, sizeof(IA_NA));
	TT.length += sizeof(IA_NA);
	}

	//static void mode_raw(int *sock_t)
	static void mode_raw()
	{
	int constone = 1;
	struct sockaddr_ll sockll;

	if (TT.sock > 0) xclose(TT.sock);
	TT.sock = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IPV6));

	memset(&sockll, 0, sizeof(sockll));
	sockll.sll_family = AF_PACKET;
	sockll.sll_protocol = htons(ETH_P_IPV6);
	sockll.sll_ifindex = if_nametoindex(TT.interface_name);
	if (bind(TT.sock, (struct sockaddr *) &sockll, sizeof(sockll))) {
	xclose(TT.sock);
	error_exit("MODE RAW : Bind fail.\n");
	}
	if (setsockopt(TT.sock, SOL_PACKET, PACKET_HOST,&constone, sizeof(int)) < 0) {
	if (errno != ENOPROTOOPT) error_exit("MODE RAW : Bind fail.\n");
	}
	}

	static void generate_transection_id()
	{
	int i, r = rand() % 0xffffff;

	for (i=0; i<3; i++) {
	TT.transction_id[i] = r%0xff;
	r = r/10;
	}
	}

	static void set_timeout(int seconds)
	{
	TT.tv.tv_sec = seconds;
	TT.tv.tv_usec = 100000;
	}

	static void send_msg(int type)
	{
	struct sockaddr_in6 addr6;
	int sendlength = 0;

	memset(&addr6, 0, sizeof(addr6));
	addr6.sin6_family = AF_INET6;
	addr6.sin6_port = htons(DHCPC_SERVER_PORT); //SERVER_PORT
	inet_pton(AF_INET6, "ff02::1:2", &addr6.sin6_addr);
	mesg.msgtype = type;
	generate_transection_id();
	memcpy(mesg.transaction_id, TT.transction_id, 3);

	if (type == DHCP6SOLICIT) {
	TT.length = 0;
	fill_clientID();
	fill_optionRequest();
	fill_elapsedTime();
	fill_iaid();
	sendlength = sizeof(dhcp6_msg_t) - 524 + TT.length;
	} else if (type == DHCP6REQUEST \|\| type == DHCP6RELEASE \|\| type == DHCP6RENEW)
	sendlength = TT.request_length;
	dbg("Sending message type: %d\n", type);
	sendlength = sendto(TT.sock1, &mesg, sendlength , 0,(struct sockaddr *)&addr6,
	sizeof(struct sockaddr_in6 ));
	if (sendlength <= 0) dbg("Error in sending message type: %d\n", type);
	}

	uint8_t get_msg_ptr(uint8_t data, int data_length, int msgtype)
	{
	uint16_t type = ((uint16_t)data), length = ((uint16_t)(data+2));

	type = ntohs(type);
	if (type == msgtype) return data;
	length = ntohs(length);
	while (type != msgtype) {
	data_length -= (4 + length);
	if (data_length <= 0) break;
	data = data + 4 + length;
	type = ntohs(((uint16_t)data));
	length = ntohs(((uint16_t)(data+2)));
	if (type == msgtype) return data;
	}
	return NULL;
	}

	static uint8_t check_server_id(uint8_t data, int data_length)
	{
	return get_msg_ptr(data, data_length, DHCP6_OPT_SERVERID);
	}

	static int check_client_id(uint8_t *data, int data_length)
	{
	if ((data = get_msg_ptr(data, data_length, DHCP6_OPT_CLIENTID))) {
	DUID one = ((DUID)(data+4));
	DUID two = ((DUID)&mesg.options[4]);

	if (!memcmp(&one, &two, sizeof(DUID))) return 1;
	}
	return 0;
	}

	static int validate_ids()
	{
	if (!check_server_id(mymsg->dhcp6.options,
	TT.status - ((char)&mymsg->dhcp6.options[0] - (char)mymsg) )) {
	dbg("Invalid server id: %d\n");
	return 0;
	}
	if (!check_client_id(mymsg->dhcp6.options,
	TT.status - ((char)&mymsg->dhcp6.options[0] - (char)mymsg) )) {
	dbg("Invalid client id: %d\n");
	return 0;
	}
	return 1;
	}

	static void parse_ia_na(uint8_t *data, int data_length)
	{
	uint8_t *t = get_msg_ptr(data, data_length, DHCP6_OPT_IA_NA);
	uint16_t iana_len, content_len = 0;

	memset(&dhcp_data,0,sizeof(dhcp_data));
	if (!t) return;

	iana_len = ntohs(((uint16_t)(t+2)));
	dhcp_data.iaid = ntohl(((uint32_t)(t+4)));
	dhcp_data.t1 = ntohl(((uint32_t)(t+8)));
	dhcp_data.t2 = ntohl(((uint32_t)(t+12)));
	t += 16;
	iana_len -= 12;

	while(iana_len > 0) {
	uint16_t sub_type = ntohs(((uint16_t)(t)));

	switch (sub_type) {
	case DHCP6_OPT_IA_ADDR:
	content_len = ntohs(((uint16_t)(t+2)));
	memcpy(dhcp_data.ipaddr,t+4,16);
	if (TT.state == DHCP6SOLICIT) {
	if (TT.req_ip) {
	struct addrinfo *res = NULL;

	if(!getaddrinfo(TT.req_ip, NULL, NULL,&res)) {
	dbg("Requesting IP: %s\n", TT.req_ip);
	memcpy (&TT.input_socket6, res->ai_addr, res->ai_addrlen);
	memcpy(t+4, TT.input_socket6.sin6_addr.__in6_u.__u6_addr8, 16);
	} else xprintf("Invalid IP: %s\n",TT.req_ip);
	freeaddrinfo(res);
	}
	}
	dhcp_data.pf_lf = ntohl(((uint32_t)(t+20)));
	dhcp_data.va_lf = ntohl(((uint32_t)(t+24)));
	iana_len -= (content_len + 4);
	t += (content_len + 4);
	break;
	case DHCP6_OPT_STATUS_CODE:
	content_len = ntohs(((uint16_t)(t+2)));
	dhcp_data.status_code = ntohs(((uint16_t)(t+4)));
	iana_len -= (content_len + 4);
	t += (content_len + 4);
	break;
	default:
	content_len = ntohs(((uint16_t)(t+2)));
	iana_len -= (content_len + 4);
	t += (content_len + 4);
	break;
	}
	}
	}

	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);
	}
	}

	// Creates environment pointers from RES to use in script
	static int fill_envp(DHCP_DATA *res)
	{
	int ret = setenv("interface", TT.interface_name, 1);

	if (ret) return ret;
	inet_ntop(AF_INET6, res->ipaddr, toybuf, INET6_ADDRSTRLEN);
	ret = setenv("ip",(const char*)toybuf , 1);
	return ret;
	}

	// Executes Script NAME.
	static void run_script(DHCP_DATA res, char name)
	{
	volatile int error = 0;
	struct stat sts;
	pid_t pid;
	char *argv[3];
	char *script = (toys.optflags & FLAG_s) ? TT.script
	: "/usr/share/dhcp/default.script";

	if (stat(script, &sts) == -1 && errno == ENOENT) return;
	if (!res \|\| fill_envp(res)) {
	dbg("Failed to create environment variables.\n");
	return;
	}
	dbg("Executing %s %s\n", script, name);
	argv[0] = (char*)script;
	argv[1] = (char*)name;
	argv[2] = NULL;
	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;
	perror_msg("script exec failed");
	}
	dbg("script complete.\n");
	}

	static void lease_fail()
	{
	dbg("Lease failed.\n");
	run_script(NULL, "leasefail");
	if (toys.optflags & FLAG_n) {
	xclose(TT.sock);
	xclose(TT.sock1);
	error_exit("Lease Failed, Exiting.");
	}
	if (toys.optflags & FLAG_b) {
	dbg("Lease failed. Going to daemon mode.\n");
	if (daemon(0,0)) perror_exit("daemonize");
	if (toys.optflags & FLAG_p) write_pid(TT.pidfile);
	toys.optflags &= ~FLAG_b;
	toys.optflags \|= FLAG_f;
	}
	}

	// Generic signal handler real handling is done in main funcrion.
	static void signal_handler(int sig)
	{
	dbg("Caught signal: %d\n", sig);
	switch (sig) {
	case SIGUSR1:
	dbg("SIGUSR1.\n");
	if (TT.state == DHCP6RELEASE \|\| TT.state == DHCP6REQUEST ) {
	TT.state = DHCP6SOLICIT;
	set_timeout(0);
	return;
	}
	dbg("SIGUSR1 sending renew.\n");
	send_msg(DHCP6RENEW);
	TT.state = DHCP6RENEW;
	TT.retries = 0;
	set_timeout(0);
	break;
	case SIGUSR2:
	dbg("SIGUSR2.\n");
	if (TT.state == DHCP6RELEASE) return;
	if (TT.state != DHCP6CONFIRM ) return;
	dbg("SIGUSR2 sending release.\n");
	send_msg(DHCP6RELEASE);
	TT.state = DHCP6RELEASE;
	TT.retries = 0;
	set_timeout(0);
	break;
	case SIGTERM:
	case SIGINT:
	dbg((sig == SIGTERM)?"SIGTERM.\n":"SIGINT.\n");
	if ((toys.optflags & FLAG_R) && TT.state == DHCP6CONFIRM)
	send_msg(DHCP6RELEASE);
	if(sig == SIGINT) exit(0);
	break;
	default: break;
	}
	}

	// signal setup for SIGUSR1 SIGUSR2 SIGTERM
	static int setup_signal()
	{
	signal(SIGUSR1, signal_handler);
	signal(SIGUSR2, signal_handler);
	signal(SIGTERM, signal_handler);
	signal(SIGINT, signal_handler);
	return 0;
	}

	void dhcp6_main(void)
	{
	struct sockaddr_in6 sinaddr6;
	int constone = 1;
	fd_set rfds;

	srand(time(NULL));
	setlinebuf(stdout);
	dbg = dummy;
	TT.state = DHCP6SOLICIT;

	if (toys.optflags & FLAG_v) dbg = logit;
	if (!TT.interface_name) TT.interface_name = "eth0";
	if (toys.optflags & FLAG_p) write_pid(TT.pidfile);
	if (!TT.retry) TT.retry = 3;
	if (!TT.timeout) TT.timeout = 3;
	if (!TT.errortimeout) TT.errortimeout = 20;
	if (toys.optflags & FLAG_S) {
	openlog("DHCP6 :", LOG_PID, LOG_DAEMON);
	dbg = logit;
	}

	dbg("Interface: %s\n", TT.interface_name);
	dbg("pid file: %s\n", TT.pidfile);
	dbg("Retry count: %d\n", TT.retry);
	dbg("Timeout : %d\n", TT.timeout);
	dbg("Error timeout: %d\n", TT.errortimeout);



	setup_signal();
	TT.sock1 = xsocket(PF_INET6, SOCK_DGRAM, 0);
	memset(&sinaddr6, 0, sizeof(sinaddr6));
	sinaddr6.sin6_family = AF_INET6;
	sinaddr6.sin6_port = htons(DHCPC_CLIENT_PORT);
	sinaddr6.sin6_scope_id = if_nametoindex(TT.interface_name);
	sinaddr6.sin6_addr = in6addr_any ;

	xsetsockopt(TT.sock1, SOL_SOCKET, SO_REUSEADDR, &constone, sizeof(constone));

	if (bind(TT.sock1, (struct sockaddr *)&sinaddr6, sizeof(sinaddr6))) {
	xclose(TT.sock1);
	error_exit("bind failed");
	}

	mode_raw();
	set_timeout(0);
	for (;;) {
	int maxfd = TT.sock;

	if (TT.sock >= 0) FD_SET(TT.sock, &rfds);
	TT.retval = 0;
	if ((TT.retval = select(maxfd + 1, &rfds, NULL, NULL, &TT.tv)) < 0) {
	if(errno == EINTR) continue;
	perror_exit("Error in select");
	}
	if (!TT.retval) {
	if (TT.state == DHCP6SOLICIT \|\| TT.state == DHCP6CONFIRM) {
	dbg("State is solicit, sending solicit packet\n");
	run_script(NULL, "deconfig");
	send_msg(DHCP6SOLICIT);
	TT.state = DHCP6SOLICIT;
	TT.retries++;
	if(TT.retries > TT.retry) set_timeout(TT.errortimeout);
	else if (TT.retries == TT.retry) {
	dbg("State is solicit, retry count is max.\n");
	lease_fail();
	set_timeout(TT.errortimeout);
	} else set_timeout(TT.timeout);
	continue;
	} else if (TT.state == DHCP6REQUEST \|\| TT.state == DHCP6RENEW \|\|
	TT.state == DHCP6RELEASE) {
	dbg("State is %d , sending packet\n", TT.state);
	send_msg(TT.state);
	TT.retries++;
	if (TT.retries > TT.retry) set_timeout(TT.errortimeout);
	else if (TT.retries == TT.retry) {
	lease_fail();
	set_timeout(TT.errortimeout);
	} else set_timeout(TT.timeout);
	continue;
	}
	} else if (FD_ISSET(TT.sock, &rfds)) {
	if ((TT.status = read(TT.sock, toybuf, sizeof(toybuf))) <= 0) continue;
	mymsg = (dhcp6_raw_t*)toybuf;
	if (ntohs(mymsg->udph.dest) == 546 &&
	!memcmp(mymsg->dhcp6.transaction_id, TT.transction_id, 3)) {
	if (TT.state == DHCP6SOLICIT) {
	if (mymsg->dhcp6.msgtype == DHCP6ADVERTISE ) {
	if (!validate_ids()) {
	dbg("Invalid id recieved, solicit.\n");
	TT.state = DHCP6SOLICIT;
	continue;
	}
	dbg("Got reply to request or solicit.\n");
	TT.retries = 0;
	set_timeout(0);
	TT.request_length = TT.status - ((char)&mymsg->dhcp6 - (char)mymsg);
	memcpy((uint8_t*)&mesg, &mymsg->dhcp6, TT.request_length);
	parse_ia_na(mesg.options, TT.request_length);
	dbg("Status code:%d\n", dhcp_data.status_code);
	inet_ntop(AF_INET6, dhcp_data.ipaddr, toybuf, INET6_ADDRSTRLEN);
	dbg("Advertiesed IP: %s\n", toybuf);
	TT.state = DHCP6REQUEST;
	} else {
	dbg("Invalid solicit.\n");
	continue;
	}
	} else if (TT.state == DHCP6REQUEST \|\| TT.state == DHCP6RENEW ) {
	if (mymsg->dhcp6.msgtype == DHCP6REPLY) {
	if (!validate_ids()) {
	dbg("Invalid id recieved, %d.\n", TT.state);
	TT.state = DHCP6REQUEST;
	continue;
	}
	dbg("Got reply to request or renew.\n");
	TT.request_length = TT.status - ((char)&mymsg->dhcp6 - (char)mymsg);
	memcpy((uint8_t*)&mesg, &mymsg->dhcp6, TT.request_length);
	parse_ia_na(mymsg->dhcp6.options, TT.request_length);
	dbg("Status code:%d\n", dhcp_data.status_code);
	inet_ntop(AF_INET6, dhcp_data.ipaddr, toybuf, INET6_ADDRSTRLEN);
	dbg("Got IP: %s\n", toybuf);
	TT.retries = 0;
	run_script(&dhcp_data, (TT.state == DHCP6REQUEST) ?
	"request" : "renew");
	if (toys.optflags & FLAG_q) {
	if (toys.optflags & FLAG_R) send_msg(DHCP6RELEASE);
	break;
	}
	TT.state = DHCP6CONFIRM;
	set_timeout((dhcp_data.va_lf)?dhcp_data.va_lf:INT_MAX);
	dbg("Setting timeout to intmax.");
	if (TT.state == DHCP6REQUEST \|\| !(toys.optflags & FLAG_f)) {
	dbg("Making it a daemon\n");
	if (daemon(0,0)) perror_exit("daemonize");
	toys.optflags \|= FLAG_f;
	if (toys.optflags & FLAG_p) write_pid(TT.pidfile);
	}
	dbg("Making it a foreground.\n");
	continue;
	} else {
	dbg("Invalid reply.\n");
	continue;
	}
	} else if (TT.state == DHCP6RELEASE) {
	dbg("Got reply to release.\n");
	run_script(NULL, "release");
	set_timeout(INT_MAX);
	}
	}
	}
	}
	xclose(TT.sock1);
	xclose(TT.sock);
	}