Fix error in IPv6 prefix calculation.

Error with prefixed address assignment. When it is calculating number of
addresses from prefixlen, it rotates only 32bit int instead of 64b uint.
Only result is assigned to 64b variable.

Two examples:

dhcp-host=[2000::1230:0:0/92],correct-prefix
dhcp-host=[2000::1234:5678:0/92],incorrect-prefix

If prefix length is lower than 96, the result is zero. It means
incorrect-prefix is not refused as it should. Fix is simple, attaching
patch with it. Just rotate 64b int.

src/dhcp-common.c

@@ -649,7 +649,7 @@ static const struct opttab_t opttab6[] = {
   { "sntp-server", 31,  OT_ADDR_LIST },
   { "information-refresh-time", 32, OT_TIME },
   { "FQDN", 39, OT_INTERNAL | OT_RFC1035_NAME },
-  { "ntp-server", 56,  0 },
+  { "ntp-server", 56, 0 /* OT_ADDR_LIST | OT_RFC1035_NAME */ },
   { "bootfile-url", 59, OT_NAME },
   { "bootfile-param", 60, OT_CSTRING },
   { NULL, 0, 0 }

src/dhcp6-protocol.h

@@ -59,8 +59,12 @@
 #define OPTION6_REMOTE_ID       37
 #define OPTION6_SUBSCRIBER_ID   38
 #define OPTION6_FQDN            39
+#define OPTION6_NTP_SERVER      56
 #define OPTION6_CLIENT_MAC      79
 
+#define NTP_SUBOPTION_SRV_ADDR  1
+#define NTP_SUBOPTION_MC_ADDR   2
+#define NTP_SUBOPTION_SRV_FQDN  3
 
 #define DHCP6SUCCESS     0
 #define DHCP6UNSPEC      1

src/dnsmasq.c

@@ -1860,7 +1860,8 @@ static void check_dns_listeners(time_t now)
 		    if (daemon->tcp_pids[i] == 0 && daemon->tcp_pipes[i] == -1)
 		      {
 			char a;
-			
+			(void)a; /* suppress potential unused warning */
+
 			daemon->tcp_pids[i] = p;
 			daemon->tcp_pipes[i] = pipefd[0];
 #ifdef HAVE_LINUX_NETWORK
@@ -1911,6 +1912,7 @@ static void check_dns_listeners(time_t now)
 	      if (!option_bool(OPT_DEBUG))
 		{
 		  char a = 0;
+		  (void)a; /* suppress potential unused warning */
 		  alarm(CHILD_LIFETIME);
 		  close(pipefd[0]); /* close read end in child. */
 		  daemon->pipe_to_parent = pipefd[1];

src/forward.c

@@ -93,10 +93,13 @@ int send_from(int fd, int nowild, char *packet, size_t len,
   
   while (retry_send(sendmsg(fd, &msg, 0)));
 
-  /* If interface is still in DAD, EINVAL results - ignore that. */
-  if (errno != 0 && errno != EINVAL)
+  if (errno != 0)
     {
-      my_syslog(LOG_ERR, _("failed to send packet: %s"), strerror(errno));
+#ifdef HAVE_LINUX_NETWORK
+      /* If interface is still in DAD, EINVAL results - ignore that. */
+      if (errno != EINVAL)
+	my_syslog(LOG_ERR, _("failed to send packet: %s"), strerror(errno));
+#endif
       return 0;
     }
   

src/network.c

@@ -785,6 +785,8 @@ int set_ipv6pktinfo(int fd)
 /* Find the interface on which a TCP connection arrived, if possible, or zero otherwise. */
 int tcp_interface(int fd, int af)
 { 
+  (void)fd; /* suppress potential unused warning */
+  (void)af; /* suppress potential unused warning */
   int if_index = 0;
 
 #ifdef HAVE_LINUX_NETWORK
@@ -1187,6 +1189,7 @@ int local_bind(int fd, union mysockaddr *addr, char *intname, unsigned int ifind
 #endif
     }
 
+  (void)intname; /* suppress potential unused warning */
 #if defined(SO_BINDTODEVICE)
   if (intname[0] != 0 &&
       setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, intname, IF_NAMESIZE) == -1)

src/option.c

@@ -1260,6 +1260,12 @@ static int parse_dhcp_opt(char *errstr, char *arg, int flags)
 
       if (!found_colon)
 	is_addr6 = 0;
+
+#ifdef HAVE_DHCP6
+      /* NTP server option takes hex, addresses or FQDN */
+      if (is6 && new->opt == OPTION6_NTP_SERVER && !is_hex)
+	opt_len |= is_addr6 ? OT_ADDR_LIST : OT_RFC1035_NAME;
+#endif
      
       /* We know that some options take addresses */
       if (opt_len & OT_ADDR_LIST)
@@ -1521,8 +1527,9 @@ static int parse_dhcp_opt(char *errstr, char *arg, int flags)
 	    }
 	  else if (comma && (opt_len & OT_RFC1035_NAME))
 	    {
-	      unsigned char *p = NULL, *newp, *end;
+	      unsigned char *p = NULL, *q, *newp, *end;
 	      int len = 0;
+	      int header_size = (is6 && new->opt == OPTION6_NTP_SERVER) ? 4 : 0;
 	      arg = comma;
 	      comma = split(arg);
 	      
@@ -1532,7 +1539,7 @@ static int parse_dhcp_opt(char *errstr, char *arg, int flags)
 		  if (!dom)
 		    goto_err(_("bad domain in dhcp-option"));
 		    		  
-		  newp = opt_malloc(len + strlen(dom) + 2);
+		  newp = opt_malloc(len + header_size + strlen(dom) + 2);
 		  
 		  if (p)
 		    {
@@ -1541,8 +1548,14 @@ static int parse_dhcp_opt(char *errstr, char *arg, int flags)
 		    }
 		  
 		  p = newp;
-		  end = do_rfc1035_name(p + len, dom, NULL);
+		  q = p + len;
+		  end = do_rfc1035_name(q + header_size, dom, NULL);
 		  *end++ = 0;
+		  if (is6 && new->opt == OPTION6_NTP_SERVER)
+		    {
+		      PUTSHORT(NTP_SUBOPTION_SRV_FQDN, q);
+		      PUTSHORT(end - q - 2, q);
+		    }
 		  len = end - p;
 		  free(dom);
 
@@ -3309,7 +3322,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 			
 			if (!atoi_check(pref, &new_addr->prefixlen) ||
 			    new_addr->prefixlen > 128 ||
-			    (((1<<(128-new_addr->prefixlen))-1) & addrpart) != 0)
+			    ((((u64)1<<(128-new_addr->prefixlen))-1) & addrpart) != 0)
 			  {
 			    dhcp_config_free(new);
 			    ret_err(_("bad IPv6 prefix"));

src/rfc3315.c

@@ -1311,23 +1311,39 @@ static struct dhcp_netid *add_options(struct state *state, int do_refresh)
 	      	  
 	      for (a = (struct in6_addr *)opt_cfg->val, j = 0; j < opt_cfg->len; j+=IN6ADDRSZ, a++)
 		{
+		  struct in6_addr *p = NULL;
+
 		  if (IN6_IS_ADDR_UNSPECIFIED(a))
 		    {
 		      if (!add_local_addrs(state->context))
-			put_opt6(state->fallback, IN6ADDRSZ);
+			p = state->fallback;
 		    }
 		  else if (IN6_IS_ADDR_ULA_ZERO(a))
 		    {
 		      if (!IN6_IS_ADDR_UNSPECIFIED(state->ula_addr))
-			put_opt6(state->ula_addr, IN6ADDRSZ);
+			p = state->ula_addr;
 		    }
 		  else if (IN6_IS_ADDR_LINK_LOCAL_ZERO(a))
 		    {
 		      if (!IN6_IS_ADDR_UNSPECIFIED(state->ll_addr))
-			put_opt6(state->ll_addr, IN6ADDRSZ);
+			p = state->ll_addr;
 		    }
 		  else
-		    put_opt6(a, IN6ADDRSZ);
+		    p = a;
+
+		  if (!p)
+		    continue;
+		  else if (opt_cfg->opt == OPTION6_NTP_SERVER)
+		    {
+		      if (IN6_IS_ADDR_MULTICAST(p))
+			o1 = new_opt6(NTP_SUBOPTION_MC_ADDR);
+		      else
+			o1 = new_opt6(NTP_SUBOPTION_SRV_ADDR);
+		      put_opt6(p, IN6ADDRSZ);
+		      end_opt6(o1);
+		    }
+		  else
+		    put_opt6(p, IN6ADDRSZ);
 		}
 
 	      end_opt6(o);
@@ -1708,14 +1724,14 @@ static int config_valid(struct dhcp_config *config, struct dhcp_context *context
     return 0;
 
   for (addr_list = config->addr6; addr_list; addr_list = addr_list->next)
-    if (!(addr_list->flags && ADDRLIST_DECLINED) ||
+    if (!(addr_list->flags & ADDRLIST_DECLINED) ||
 	difftime(now, addr_list->decline_time) >= (float)DECLINE_BACKOFF)
       {
 	addrpart = addr6part(&addr_list->addr.addr6);
 	addresses = 1;
 	
 	if (addr_list->flags & ADDRLIST_PREFIX)
-	  addresses = 1<<(128-addr_list->prefixlen);
+	  addresses = (u64)1<<(128-addr_list->prefixlen);
 	
 	if ((addr_list->flags & ADDRLIST_WILDCARD))
 	  {