Fix DHCPv6 lease time calculation when client sends VL==0 or PL==0

src/rfc3315.c

@@ -54,13 +54,13 @@ static struct prefix_class *prefix_class_from_context(struct dhcp_context *conte
 static void mark_context_used(struct state *state, struct dhcp_context *context, struct in6_addr *addr);
 static void mark_config_used(struct dhcp_context *context, struct in6_addr *addr);
 static int check_address(struct state *state, struct in6_addr *addr);
-static void add_address(struct state *state, struct dhcp_context *context, unsigned int lease_time, unsigned int requested_time, 
+static void add_address(struct state *state, struct dhcp_context *context, unsigned int lease_time, void *ia_option, 
 			unsigned int *min_time, struct in6_addr *addr, int update_lease, time_t now);
 static void update_leases(struct state *state, struct dhcp_context *context, struct in6_addr *addr, unsigned int lease_time, time_t now);
 static int add_local_addrs(struct dhcp_context *context);
 static struct dhcp_netid *add_options(struct state *state, struct in6_addr *fallback, struct dhcp_context *context, int do_refresh);
 static void calculate_times(struct dhcp_context *context, unsigned int *min_time, unsigned int *valid_timep, 
-			    unsigned int *preferred_timep, unsigned int lease_time, unsigned int requested_time);
+			    unsigned int *preferred_timep, unsigned int lease_time);
 
 #define opt6_len(opt) ((int)(opt6_uint(opt, -2, 2)))
 #define opt6_type(opt) (opt6_uint(opt, -4, 2))
@@ -574,7 +574,7 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 	    /* set unless we're sending a particular prefix-class, when we
 	       want only dhcp-ranges with the correct tags set and not those without any tags. */
 	    int plain_range = 1;
-	    u32 lease_time, requested_time;
+	    u32 lease_time;
 	    struct dhcp_lease *ltmp;
 	    struct in6_addr *req_addr;
 	    struct in6_addr addr;
@@ -645,8 +645,7 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 	    for (ia_counter = 0; ia_option; ia_counter++, ia_option = opt6_find(opt6_next(ia_option, ia_end), ia_end, OPTION6_IAADDR, 24))
 	      {
 		req_addr = opt6_ptr(ia_option, 0);
-		requested_time = opt6_uint(ia_option, 16, 4);
-		
+				
 		if ((c = address6_valid(context, req_addr, solicit_tags, plain_range)))
 		  {
 		    lease_time = c->lease_time;
@@ -670,7 +669,7 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 		    if (dump_all_prefix_classes && state.ia_type == OPTION6_IA_NA)
 		      state.send_prefix_class = prefix_class_from_context(c);
 #endif		    
-		    add_address(&state, c, lease_time, requested_time, &min_time, req_addr, rapid_commit != NULL, now);
+		    add_address(&state, c, lease_time, ia_option, &min_time, req_addr, rapid_commit != NULL, now);
 		    mark_context_used(&state, context, req_addr);
 		    get_context_tag(&state, c);
 		    address_assigned = 1;
@@ -694,7 +693,7 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 		  if (dump_all_prefix_classes && state.ia_type == OPTION6_IA_NA)
 		    state.send_prefix_class = prefix_class_from_context(c);
 #endif
-		  add_address(&state, c, lease_time, lease_time, &min_time, &addr, rapid_commit != NULL, now);
+		  add_address(&state, c, lease_time, NULL, &min_time, &addr, rapid_commit != NULL, now);
 		  mark_context_used(&state, context, &addr);
 		  get_context_tag(&state, c);
 		  address_assigned = 1;
@@ -711,7 +710,7 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 		    if (dump_all_prefix_classes && state.ia_type == OPTION6_IA_NA)
 		      state.send_prefix_class = prefix_class_from_context(c);
 #endif
-		    add_address(&state, c, c->lease_time, c->lease_time, &min_time, req_addr, rapid_commit != NULL, now);
+		    add_address(&state, c, c->lease_time, NULL, &min_time, req_addr, rapid_commit != NULL, now);
 		    mark_context_used(&state, context, req_addr);
 		    get_context_tag(&state, c);
 		    address_assigned = 1;
@@ -725,7 +724,7 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 		if (dump_all_prefix_classes && state.ia_type == OPTION6_IA_NA)
 		  state.send_prefix_class = prefix_class_from_context(c);
 #endif
-		add_address(&state, c, c->lease_time, c->lease_time, &min_time, &addr, rapid_commit != NULL, now);
+		add_address(&state, c, c->lease_time, NULL, &min_time, &addr, rapid_commit != NULL, now);
 		mark_context_used(&state, context, &addr);
 		get_context_tag(&state, c);
 		address_assigned = 1;
@@ -788,7 +787,6 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 	    for (; ia_option; ia_option = opt6_find(opt6_next(ia_option, ia_end), ia_end, OPTION6_IAADDR, 24))
 	      {
 		struct in6_addr *req_addr = opt6_ptr(ia_option, 0);
-		u32 requested_time = opt6_uint(ia_option, 16, 4);
 		struct dhcp_context *dynamic, *c;
 		unsigned int lease_time;
 		struct in6_addr addr;
@@ -829,7 +827,7 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 			if (dump_all_prefix_classes && state.ia_type == OPTION6_IA_NA)
 			  state.send_prefix_class = prefix_class_from_context(c);
 #endif
-			add_address(&state, dynamic, lease_time, requested_time, &min_time, req_addr, 1, now);
+			add_address(&state, dynamic, lease_time, ia_option, &min_time, req_addr, 1, now);
 			get_context_tag(&state, dynamic);
 			address_assigned = 1;
 		      }
@@ -893,9 +891,8 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 	      {
 		struct dhcp_lease *lease = NULL;
 		struct in6_addr *req_addr = opt6_ptr(ia_option, 0);
-		u32 requested_time = opt6_uint(ia_option, 16, 4);
-		unsigned int preferred_time = 0; /* in case renewal inappropriate */
-		unsigned int valid_time = 0;
+		unsigned int preferred_time =  opt6_uint(ia_option, 16, 4);
+		unsigned int valid_time =  opt6_uint(ia_option, 20, 4);
 		char *message = NULL;
 		struct dhcp_context *this_context;
 		
@@ -915,6 +912,8 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 		    put_opt6_short(DHCP6NOBINDING);
 		    put_opt6_string(_("no binding found"));
 		    end_opt6(o1);
+
+		    preferred_time = valid_time = 0;
 		    break;
 		  }
 		
@@ -932,7 +931,7 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 		    else 
 		      lease_time = this_context->lease_time;
 		    
-		    calculate_times(this_context, &min_time, &valid_time, &preferred_time, lease_time, requested_time); 
+		    calculate_times(this_context, &min_time, &valid_time, &preferred_time, lease_time); 
 		    
 		    lease_set_expires(lease, valid_time, now);
 		    if (state.ia_type == OPTION6_IA_NA && state.hostname)
@@ -949,8 +948,11 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 		      message = _("deprecated");
 		  }
 		else
-		  message = _("address invalid");
-		
+		  {
+		    preferred_time = valid_time = 0;
+		    message = _("address invalid");
+		  }
+
 		log6_packet(&state, "DHCPREPLY", req_addr, message);	
 		
 		o1 =  new_opt6(OPTION6_IAADDR);
@@ -1500,14 +1502,21 @@ static void end_ia(int t1cntr, unsigned int min_time, int do_fuzz)
     }	
 }
 
-static void add_address(struct state *state, struct dhcp_context *context, unsigned int lease_time, unsigned int requested_time, 
+static void add_address(struct state *state, struct dhcp_context *context, unsigned int lease_time, void *ia_option, 
 			unsigned int *min_time, struct in6_addr *addr, int do_update, time_t now)
 {
-  unsigned int valid_time, preferred_time;
+  unsigned int valid_time = 0, preferred_time = 0;
   int o = new_opt6(OPTION6_IAADDR);
   struct dhcp_lease *lease;
 
-  calculate_times(context, min_time, &valid_time, &preferred_time, lease_time, requested_time); 
+  /* get client requested times */
+  if (ia_option)
+    {
+      preferred_time =  opt6_uint(ia_option, 16, 4);
+      valid_time =  opt6_uint(ia_option, 20, 4);
+    }
+
+  calculate_times(context, min_time, &valid_time, &preferred_time, lease_time); 
   
   put_opt6(addr, sizeof(*addr));
   put_opt6_long(preferred_time);
@@ -1591,22 +1600,60 @@ static int check_address(struct state *state, struct in6_addr *addr)
   return 1;
 }
 
+
+/* Calculate valid and preferred times to send in leases/renewals. 
+
+   Inputs are:
+
+   *valid_timep, *preferred_timep - requested times from IAADDR options.
+   context->valid, context->preferred - times associated with subnet address on local interface.
+   context->flags | CONTEXT_DEPRECATE - "deprecated" flag in dhcp-range.
+   lease_time - configured time for context for individual client.
+   *min_time - smallest valid time sent so far.
+
+   Outputs are :
+   
+   *valid_timep, *preferred_timep - times to be send in IAADDR option.
+   *min_time - smallest valid time sent so far, to calculate T1 and T2.
+   
+   */
 static void calculate_times(struct dhcp_context *context, unsigned int *min_time, unsigned int *valid_timep, 
-			    unsigned int *preferred_timep, unsigned int lease_time, unsigned int requested_time)
+			    unsigned int *preferred_timep, unsigned int lease_time)
 {
-  unsigned int preferred_time, valid_time;
-
-  if (requested_time < 120u )
-    requested_time = 120u; /* sanity */
-  if (lease_time == 0xffffffff || (requested_time != 0xffffffff && requested_time < lease_time))
-    lease_time = requested_time;
-		    
-  valid_time = (context->valid < lease_time) ? context->valid : lease_time;
-  preferred_time = (context->preferred < lease_time) ? context->preferred : lease_time;
+  unsigned int req_preferred = *preferred_timep, req_valid = *valid_timep;
+  unsigned int valid_time = lease_time, preferred_time = lease_time;
+  
+  /* RFC 3315: "A server ignores the lifetimes set
+     by the client if the preferred lifetime is greater than the valid
+     lifetime. */
+  if (req_preferred <= req_valid)
+    {
+      if (req_preferred != 0)
+	{
+	  /* 0 == "no preference from client" */
+	  if (req_preferred < 120u)
+	    req_preferred = 120u; /* sanity */
+	  
+	  if (req_preferred < preferred_time)
+	    preferred_time = req_preferred;
+	}
+      
+      if (req_valid != 0)
+	/* 0 == "no preference from client" */
+	{
+	  if (req_valid < 120u)
+	    req_valid = 120u; /* sanity */
+	  
+	  if (req_valid < valid_time)
+	    valid_time = req_valid;
+	}
+    }
 
-  if (context->flags & CONTEXT_DEPRECATE)
+  /* deprecate (preferred == 0) which configured, or when local address 
+     is deprecated */
+  if ((context->flags & CONTEXT_DEPRECATE) || context->preferred == 0)
     preferred_time = 0;
-
+  
   if (preferred_time != 0 && preferred_time < *min_time)
     *min_time = preferred_time;