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authorDavid Ahern <dsahern@gmail.com>2019-05-25 00:43:08 +0300
committerDavid S. Miller <davem@davemloft.net>2019-05-29 07:37:30 +0300
commit430a049190de3c9e219f43084de9f1122da04570 (patch)
treeb846b64bcf7696f24db792a5c710a008f643ff4c /include/net/nexthop.h
parentb513bd035f4044aa2667fb01418918523a049b9c (diff)
downloadlinux-430a049190de3c9e219f43084de9f1122da04570.tar.xz
nexthop: Add support for nexthop groups
Allow the creation of nexthop groups which reference other nexthop objects to create multipath routes: +--------------+ +------------+ +--------------+ | | nh nh_grp --->| nh_grp_entry |-+ +------------+ +---------|----+ ^ | | +------------+ +----------------+ +--->| nh, weight | nh_parent +------------+ A group entry points to a nexthop with a weight for that hop within the group. The nexthop has a list_head, grp_list, for tracking which groups it is a member of and the group entry has a reference back to the parent. The grp_list is used when a nexthop is deleted - to efficiently remove it from groups using it. If a nexthop group spec is given, no other attributes can be set. Each nexthop id in a group spec must already exist. Similar to single nexthops, the specification of a nexthop group can be updated so that data is managed with rcu locking. Add path selection function to account for multiple paths and add ipv{4,6}_good_nh helpers to know that if a neighbor entry exists it is in a good state. Update NETDEV event handling to rebalance multipath nexthop groups if a nexthop is deleted due to a link event (down or unregister). When a nexthop is removed any groups using it are updated. Groups using a nexthop a tracked via a grp_list. Nexthop dumps can be limited to groups only by adding NHA_GROUPS to the request. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/nexthop.h')
-rw-r--r--include/net/nexthop.h98
1 files changed, 97 insertions, 1 deletions
diff --git a/include/net/nexthop.h b/include/net/nexthop.h
index 7cde03337e14..6e1b8f53624c 100644
--- a/include/net/nexthop.h
+++ b/include/net/nexthop.h
@@ -35,6 +35,9 @@ struct nh_config {
struct in6_addr ipv6;
} gw;
+ struct nlattr *nh_grp;
+ u16 nh_grp_type;
+
struct nlattr *nh_encap;
u16 nh_encap_type;
@@ -56,20 +59,39 @@ struct nh_info {
};
};
+struct nh_grp_entry {
+ struct nexthop *nh;
+ u8 weight;
+ atomic_t upper_bound;
+
+ struct list_head nh_list;
+ struct nexthop *nh_parent; /* nexthop of group with this entry */
+};
+
+struct nh_group {
+ u16 num_nh;
+ bool mpath;
+ bool has_v4;
+ struct nh_grp_entry nh_entries[0];
+};
+
struct nexthop {
struct rb_node rb_node; /* entry on netns rbtree */
+ struct list_head grp_list; /* nh group entries using this nh */
struct net *net;
u32 id;
u8 protocol; /* app managing this nh */
u8 nh_flags;
+ bool is_group;
refcount_t refcnt;
struct rcu_head rcu;
union {
struct nh_info __rcu *nh_info;
+ struct nh_group __rcu *nh_grp;
};
};
@@ -88,12 +110,86 @@ static inline void nexthop_put(struct nexthop *nh)
call_rcu(&nh->rcu, nexthop_free_rcu);
}
+static inline bool nexthop_is_multipath(const struct nexthop *nh)
+{
+ if (nh->is_group) {
+ struct nh_group *nh_grp;
+
+ nh_grp = rcu_dereference_rtnl(nh->nh_grp);
+ return nh_grp->mpath;
+ }
+ return false;
+}
+
+struct nexthop *nexthop_select_path(struct nexthop *nh, int hash);
+
+static inline unsigned int nexthop_num_path(const struct nexthop *nh)
+{
+ unsigned int rc = 1;
+
+ if (nexthop_is_multipath(nh)) {
+ struct nh_group *nh_grp;
+
+ nh_grp = rcu_dereference_rtnl(nh->nh_grp);
+ rc = nh_grp->num_nh;
+ } else {
+ const struct nh_info *nhi;
+
+ nhi = rcu_dereference_rtnl(nh->nh_info);
+ if (nhi->reject_nh)
+ rc = 0;
+ }
+
+ return rc;
+}
+
+static inline
+struct nexthop *nexthop_mpath_select(const struct nexthop *nh, int nhsel)
+{
+ const struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp);
+
+ /* for_nexthops macros in fib_semantics.c grabs a pointer to
+ * the nexthop before checking nhsel
+ */
+ if (nhsel > nhg->num_nh)
+ return NULL;
+
+ return nhg->nh_entries[nhsel].nh;
+}
+
+static inline
+int nexthop_mpath_fill_node(struct sk_buff *skb, struct nexthop *nh)
+{
+ struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
+ int i;
+
+ for (i = 0; i < nhg->num_nh; i++) {
+ struct nexthop *nhe = nhg->nh_entries[i].nh;
+ struct nh_info *nhi = rcu_dereference_rtnl(nhe->nh_info);
+ struct fib_nh_common *nhc = &nhi->fib_nhc;
+ int weight = nhg->nh_entries[i].weight;
+
+ if (fib_add_nexthop(skb, nhc, weight) < 0)
+ return -EMSGSIZE;
+ }
+
+ return 0;
+}
+
/* called with rcu lock */
static inline bool nexthop_is_blackhole(const struct nexthop *nh)
{
const struct nh_info *nhi;
- nhi = rcu_dereference(nh->nh_info);
+ if (nexthop_is_multipath(nh)) {
+ if (nexthop_num_path(nh) > 1)
+ return false;
+ nh = nexthop_mpath_select(nh, 0);
+ if (!nh)
+ return false;
+ }
+
+ nhi = rcu_dereference_rtnl(nh->nh_info);
return nhi->reject_nh;
}
#endif