Minor changes

nest/route.h

@@ -174,7 +174,7 @@ struct hostentry {
   ip_addr addr;				/* IP address of host, part of key */
   ip_addr link;				/* (link-local) IP address of host, used as gw
 					   if host is directly attached */
-  struct rtable *tab;			/* Dependent table, part of key*/
+  struct rtable *tab;			/* Dependent table, part of key */
   struct hostentry *next;		/* Next in hash chain */
   unsigned hash_key;			/* Hash key */
   unsigned uc;				/* Use count */
@@ -507,19 +507,25 @@ void rta_show(struct cli *, rta *, ea_list *);
 void rta_set_recursive_next_hop(rtable *dep, rta *a, rtable *tab, ip_addr *gw, ip_addr *ll);
 
 /*
- * rta_set_recursive_next_hop() acquires hostentry from hostcache and
- * fills rta->hostentry field.  New hostentry has zero use
- * count. Cached rta locks its hostentry (increases its use count),
- * uncached rta does not lock it. Hostentry with zero use count is
- * removed asynchronously during host cache update, therefore it is
- * safe to hold such hostentry temorarily. Hostentry holds a lock for
- * a 'source' rta, mainly to share multipath nexthops. There is no
- * need to hold a lock for hostentry->dep table, because that table
- * contains routes responsible for that hostentry, and therefore is
- * non-empty if given hostentry has non-zero use count. The protocol
- * responsible for routes with recursive next hops should also hold a
- * lock for a table governing that routes (argument tab to
- * rta_set_recursive_next_hop()).
+ * rta_set_recursive_next_hop() acquires hostentry from hostcache and fills
+ * rta->hostentry field.  New hostentry has zero use count. Cached rta locks its
+ * hostentry (increases its use count), uncached rta does not lock it. Hostentry
+ * with zero use count is removed asynchronously during host cache update,
+ * therefore it is safe to hold such hostentry temorarily. Hostentry holds a
+ * lock for a 'source' rta, mainly to share multipath nexthops.
+ *
+ * There is no need to hold a lock for hostentry->dep table, because that table
+ * contains routes responsible for that hostentry, and therefore is non-empty if
+ * given hostentry has non-zero use count. If the hostentry has zero use count,
+ * the entry is removed before dep is referenced.
+ *
+ * The protocol responsible for routes with recursive next hops should hold a
+ * lock for a 'source' table governing that routes (argument tab to
+ * rta_set_recursive_next_hop()), because its routes reference hostentries
+ * (through rta) related to the governing table. When all such routes are
+ * removed, rtas are immediately removed achieving zero uc. Then the 'source'
+ * table lock could be immediately released, although hostentries may still
+ * exist - they will be freed together with the 'source' table.
  */
 
 static inline void rt_lock_hostentry(struct hostentry *he) { if (he) he->uc++; }

sysdep/linux/netlink.c

@@ -239,6 +239,16 @@ nl_parse_attrs(struct rtattr *a, struct rtattr **k, int ksize)
     return 1;
 }
 
+static inline ip4_addr rta_get_u32(struct rtattr *a)
+{ return *(u32 *) RTA_DATA(a); }
+
+static inline ip4_addr rta_get_ip4(struct rtattr *a)
+{ return ip4_ntoh(*(ip4_addr *) RTA_DATA(a)); }
+
+static inline ip6_addr rta_get_ip6(struct rtattr *a)
+{ return ip6_ntoh(*(ip6_addr *) RTA_DATA(a)); }
+
+
 struct rtattr *
 nl_add_attr(struct nlmsghdr *h, uint bufsize, uint code, const void *data, uint dlen)
 {
@@ -420,7 +430,7 @@ nl_parse_metrics(struct rtattr *hdr, u32 *metrics, int max)
       return -1;
 
     metrics[0] |= 1 << a->rta_type;
-    metrics[a->rta_type] = *(u32 *)RTA_DATA(a);
+    metrics[a->rta_type] = rta_get_u32(a);
   }
 
   if (len > 0)
@@ -456,7 +466,7 @@ nl_parse_link(struct nlmsghdr *h, int scan)
       return;
     }
   name = RTA_DATA(a[IFLA_IFNAME]);
-  memcpy(&mtu, RTA_DATA(a[IFLA_MTU]), sizeof(u32));
+  mtu = rta_get_u32(a[IFLA_MTU]);
 
   ifi = if_find_by_index(i->ifi_index);
   if (!new)
@@ -831,7 +841,7 @@ nl_parse_route(struct nlmsghdr *h, int scan)
     }
 
   if (a[RTA_OIF])
-    memcpy(&oif, RTA_DATA(a[RTA_OIF]), sizeof(oif));
+    oif = rta_get_u32(a[RTA_OIF]);
 
   p = nl_table_map[i->rtm_table];	/* Do we know this table? */
   DBG("KRT: Got %I/%d, type=%d, oif=%d, table=%d, prid=%d, proto=%s\n", dst, i->rtm_dst_len, i->rtm_type, oif, i->rtm_table, i->rtm_protocol, p ? p->p.name : "(none)");
@@ -965,11 +975,10 @@ nl_parse_route(struct nlmsghdr *h, int scan)
   e->u.krt.src = src;
   e->u.krt.proto = i->rtm_protocol;
   e->u.krt.type = i->rtm_type;
+  e->u.krt.metric = 0;
 
   if (a[RTA_PRIORITY])
-    memcpy(&e->u.krt.metric, RTA_DATA(a[RTA_PRIORITY]), sizeof(e->u.krt.metric));
-  else
-    e->u.krt.metric = 0;
+    e->u.krt.metric = rta_get_u32(a[RTA_PRIORITY]);
 
   if (a[RTA_PREFSRC])
     {
@@ -1000,7 +1009,7 @@ nl_parse_route(struct nlmsghdr *h, int scan)
       ea->attrs[0].id = EA_KRT_REALM;
       ea->attrs[0].flags = 0;
       ea->attrs[0].type = EAF_TYPE_INT;
-      memcpy(&ea->attrs[0].u.data, RTA_DATA(a[RTA_FLOW]), 4);
+      ea->attrs[0].u.data = rta_get_u32(a[RTA_FLOW]);
     }
 
   if (a[RTA_METRICS])