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-rw-r--r--include/net/nexthop.h465
1 files changed, 465 insertions, 0 deletions
diff --git a/include/net/nexthop.h b/include/net/nexthop.h
new file mode 100644
index 000000000..fd87d727a
--- /dev/null
+++ b/include/net/nexthop.h
@@ -0,0 +1,465 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Generic nexthop implementation
+ *
+ * Copyright (c) 2017-19 Cumulus Networks
+ * Copyright (c) 2017-19 David Ahern <dsa@cumulusnetworks.com>
+ */
+
+#ifndef __LINUX_NEXTHOP_H
+#define __LINUX_NEXTHOP_H
+
+#include <linux/netdevice.h>
+#include <linux/notifier.h>
+#include <linux/route.h>
+#include <linux/types.h>
+#include <net/ip_fib.h>
+#include <net/ip6_fib.h>
+#include <net/netlink.h>
+
+#define NEXTHOP_VALID_USER_FLAGS RTNH_F_ONLINK
+
+struct nexthop;
+
+struct nh_config {
+ u32 nh_id;
+
+ u8 nh_family;
+ u8 nh_protocol;
+ u8 nh_blackhole;
+ u8 nh_fdb;
+ u32 nh_flags;
+
+ int nh_ifindex;
+ struct net_device *dev;
+
+ union {
+ __be32 ipv4;
+ struct in6_addr ipv6;
+ } gw;
+
+ struct nlattr *nh_grp;
+ u16 nh_grp_type;
+
+ struct nlattr *nh_encap;
+ u16 nh_encap_type;
+
+ u32 nlflags;
+ struct nl_info nlinfo;
+};
+
+struct nh_info {
+ struct hlist_node dev_hash; /* entry on netns devhash */
+ struct nexthop *nh_parent;
+
+ u8 family;
+ bool reject_nh;
+ bool fdb_nh;
+
+ union {
+ struct fib_nh_common fib_nhc;
+ struct fib_nh fib_nh;
+ struct fib6_nh fib6_nh;
+ };
+};
+
+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 {
+ struct nh_group *spare; /* spare group for removals */
+ u16 num_nh;
+ bool mpath;
+ bool fdb_nh;
+ bool has_v4;
+ struct nh_grp_entry nh_entries[];
+};
+
+struct nexthop {
+ struct rb_node rb_node; /* entry on netns rbtree */
+ struct list_head fi_list; /* v4 entries using nh */
+ struct list_head f6i_list; /* v6 entries using nh */
+ struct list_head fdb_list; /* fdb entries using this nh */
+ 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;
+ };
+};
+
+enum nexthop_event_type {
+ NEXTHOP_EVENT_DEL
+};
+
+int register_nexthop_notifier(struct net *net, struct notifier_block *nb);
+int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
+
+/* caller is holding rcu or rtnl; no reference taken to nexthop */
+struct nexthop *nexthop_find_by_id(struct net *net, u32 id);
+void nexthop_free_rcu(struct rcu_head *head);
+
+static inline bool nexthop_get(struct nexthop *nh)
+{
+ return refcount_inc_not_zero(&nh->refcnt);
+}
+
+static inline void nexthop_put(struct nexthop *nh)
+{
+ if (refcount_dec_and_test(&nh->refcnt))
+ call_rcu(&nh->rcu, nexthop_free_rcu);
+}
+
+static inline bool nexthop_cmp(const struct nexthop *nh1,
+ const struct nexthop *nh2)
+{
+ return nh1 == nh2;
+}
+
+static inline bool nexthop_is_fdb(const struct nexthop *nh)
+{
+ if (nh->is_group) {
+ const struct nh_group *nh_grp;
+
+ nh_grp = rcu_dereference_rtnl(nh->nh_grp);
+ return nh_grp->fdb_nh;
+ } else {
+ const struct nh_info *nhi;
+
+ nhi = rcu_dereference_rtnl(nh->nh_info);
+ return nhi->fdb_nh;
+ }
+}
+
+static inline bool nexthop_has_v4(const struct nexthop *nh)
+{
+ if (nh->is_group) {
+ struct nh_group *nh_grp;
+
+ nh_grp = rcu_dereference_rtnl(nh->nh_grp);
+ return nh_grp->has_v4;
+ }
+ return false;
+}
+
+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 (nh->is_group) {
+ struct nh_group *nh_grp;
+
+ nh_grp = rcu_dereference_rtnl(nh->nh_grp);
+ if (nh_grp->mpath)
+ rc = nh_grp->num_nh;
+ }
+
+ return rc;
+}
+
+static inline
+struct nexthop *nexthop_mpath_select(const struct nh_group *nhg, int nhsel)
+{
+ /* 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,
+ u8 rt_family)
+{
+ 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, rt_family, 0) < 0)
+ return -EMSGSIZE;
+ }
+
+ return 0;
+}
+
+/* called with rcu lock */
+static inline bool nexthop_is_blackhole(const struct nexthop *nh)
+{
+ const struct nh_info *nhi;
+
+ if (nh->is_group) {
+ struct nh_group *nh_grp;
+
+ nh_grp = rcu_dereference_rtnl(nh->nh_grp);
+ if (nh_grp->num_nh > 1)
+ return false;
+
+ nh = nh_grp->nh_entries[0].nh;
+ }
+
+ nhi = rcu_dereference_rtnl(nh->nh_info);
+ return nhi->reject_nh;
+}
+
+static inline void nexthop_path_fib_result(struct fib_result *res, int hash)
+{
+ struct nh_info *nhi;
+ struct nexthop *nh;
+
+ nh = nexthop_select_path(res->fi->nh, hash);
+ nhi = rcu_dereference(nh->nh_info);
+ res->nhc = &nhi->fib_nhc;
+}
+
+/* called with rcu read lock or rtnl held */
+static inline
+struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel)
+{
+ struct nh_info *nhi;
+
+ BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0);
+ BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0);
+
+ if (nh->is_group) {
+ struct nh_group *nh_grp;
+
+ nh_grp = rcu_dereference_rtnl(nh->nh_grp);
+ if (nh_grp->mpath) {
+ nh = nexthop_mpath_select(nh_grp, nhsel);
+ if (!nh)
+ return NULL;
+ }
+ }
+
+ nhi = rcu_dereference_rtnl(nh->nh_info);
+ return &nhi->fib_nhc;
+}
+
+/* called from fib_table_lookup with rcu_lock */
+static inline
+struct fib_nh_common *nexthop_get_nhc_lookup(const struct nexthop *nh,
+ int fib_flags,
+ const struct flowi4 *flp,
+ int *nhsel)
+{
+ struct nh_info *nhi;
+
+ if (nh->is_group) {
+ struct nh_group *nhg = rcu_dereference(nh->nh_grp);
+ int i;
+
+ for (i = 0; i < nhg->num_nh; i++) {
+ struct nexthop *nhe = nhg->nh_entries[i].nh;
+
+ nhi = rcu_dereference(nhe->nh_info);
+ if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
+ *nhsel = i;
+ return &nhi->fib_nhc;
+ }
+ }
+ } else {
+ nhi = rcu_dereference(nh->nh_info);
+ if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
+ *nhsel = 0;
+ return &nhi->fib_nhc;
+ }
+ }
+
+ return NULL;
+}
+
+static inline bool nexthop_uses_dev(const struct nexthop *nh,
+ const struct net_device *dev)
+{
+ struct nh_info *nhi;
+
+ if (nh->is_group) {
+ struct nh_group *nhg = rcu_dereference(nh->nh_grp);
+ int i;
+
+ for (i = 0; i < nhg->num_nh; i++) {
+ struct nexthop *nhe = nhg->nh_entries[i].nh;
+
+ nhi = rcu_dereference(nhe->nh_info);
+ if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
+ return true;
+ }
+ } else {
+ nhi = rcu_dereference(nh->nh_info);
+ if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
+ return true;
+ }
+
+ return false;
+}
+
+static inline unsigned int fib_info_num_path(const struct fib_info *fi)
+{
+ if (unlikely(fi->nh))
+ return nexthop_num_path(fi->nh);
+
+ return fi->fib_nhs;
+}
+
+int fib_check_nexthop(struct nexthop *nh, u8 scope,
+ struct netlink_ext_ack *extack);
+
+static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel)
+{
+ if (unlikely(fi->nh))
+ return nexthop_fib_nhc(fi->nh, nhsel);
+
+ return &fi->fib_nh[nhsel].nh_common;
+}
+
+/* only used when fib_nh is built into fib_info */
+static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel)
+{
+ WARN_ON(fi->nh);
+
+ return &fi->fib_nh[nhsel];
+}
+
+/*
+ * IPv6 variants
+ */
+int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
+ struct netlink_ext_ack *extack);
+
+/* Caller should either hold rcu_read_lock(), or RTNL. */
+static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh)
+{
+ struct nh_info *nhi;
+
+ if (nh->is_group) {
+ struct nh_group *nh_grp;
+
+ nh_grp = rcu_dereference_rtnl(nh->nh_grp);
+ nh = nexthop_mpath_select(nh_grp, 0);
+ if (!nh)
+ return NULL;
+ }
+
+ nhi = rcu_dereference_rtnl(nh->nh_info);
+ if (nhi->family == AF_INET6)
+ return &nhi->fib6_nh;
+
+ return NULL;
+}
+
+/* Variant of nexthop_fib6_nh().
+ * Caller should either hold rcu_read_lock_bh(), or RTNL.
+ */
+static inline struct fib6_nh *nexthop_fib6_nh_bh(struct nexthop *nh)
+{
+ struct nh_info *nhi;
+
+ if (nh->is_group) {
+ struct nh_group *nh_grp;
+
+ nh_grp = rcu_dereference_bh_rtnl(nh->nh_grp);
+ nh = nexthop_mpath_select(nh_grp, 0);
+ if (!nh)
+ return NULL;
+ }
+
+ nhi = rcu_dereference_bh_rtnl(nh->nh_info);
+ if (nhi->family == AF_INET6)
+ return &nhi->fib6_nh;
+
+ return NULL;
+}
+
+static inline struct net_device *fib6_info_nh_dev(struct fib6_info *f6i)
+{
+ struct fib6_nh *fib6_nh;
+
+ fib6_nh = f6i->nh ? nexthop_fib6_nh(f6i->nh) : f6i->fib6_nh;
+ return fib6_nh->fib_nh_dev;
+}
+
+static inline void nexthop_path_fib6_result(struct fib6_result *res, int hash)
+{
+ struct nexthop *nh = res->f6i->nh;
+ struct nh_info *nhi;
+
+ nh = nexthop_select_path(nh, hash);
+
+ nhi = rcu_dereference_rtnl(nh->nh_info);
+ if (nhi->reject_nh) {
+ res->fib6_type = RTN_BLACKHOLE;
+ res->fib6_flags |= RTF_REJECT;
+ res->nh = nexthop_fib6_nh(nh);
+ } else {
+ res->nh = &nhi->fib6_nh;
+ }
+}
+
+int nexthop_for_each_fib6_nh(struct nexthop *nh,
+ int (*cb)(struct fib6_nh *nh, void *arg),
+ void *arg);
+
+static inline int nexthop_get_family(struct nexthop *nh)
+{
+ struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
+
+ return nhi->family;
+}
+
+static inline
+struct fib_nh_common *nexthop_fdb_nhc(struct nexthop *nh)
+{
+ struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
+
+ return &nhi->fib_nhc;
+}
+
+static inline struct fib_nh_common *nexthop_path_fdb_result(struct nexthop *nh,
+ int hash)
+{
+ struct nh_info *nhi;
+ struct nexthop *nhp;
+
+ nhp = nexthop_select_path(nh, hash);
+ if (unlikely(!nhp))
+ return NULL;
+ nhi = rcu_dereference(nhp->nh_info);
+ return &nhi->fib_nhc;
+}
+#endif
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