367 lines
7.6 KiB
C
367 lines
7.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Generic nexthop implementation
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*
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* Copyright (c) 2017-19 Cumulus Networks
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* Copyright (c) 2017-19 David Ahern <dsa@cumulusnetworks.com>
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*/
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#ifndef __LINUX_NEXTHOP_H
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#define __LINUX_NEXTHOP_H
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#include <linux/netdevice.h>
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#include <linux/route.h>
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#include <linux/types.h>
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#include <net/ip_fib.h>
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#include <net/ip6_fib.h>
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#include <net/netlink.h>
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#define NEXTHOP_VALID_USER_FLAGS RTNH_F_ONLINK
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struct nexthop;
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struct nh_config {
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u32 nh_id;
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u8 nh_family;
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u8 nh_protocol;
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u8 nh_blackhole;
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u32 nh_flags;
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int nh_ifindex;
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struct net_device *dev;
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union {
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__be32 ipv4;
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struct in6_addr ipv6;
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} gw;
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struct nlattr *nh_grp;
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u16 nh_grp_type;
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struct nlattr *nh_encap;
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u16 nh_encap_type;
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u32 nlflags;
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struct nl_info nlinfo;
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};
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struct nh_info {
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struct hlist_node dev_hash; /* entry on netns devhash */
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struct nexthop *nh_parent;
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u8 family;
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bool reject_nh;
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union {
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struct fib_nh_common fib_nhc;
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struct fib_nh fib_nh;
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struct fib6_nh fib6_nh;
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};
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};
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struct nh_grp_entry {
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struct nexthop *nh;
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u8 weight;
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atomic_t upper_bound;
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struct list_head nh_list;
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struct nexthop *nh_parent; /* nexthop of group with this entry */
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};
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struct nh_group {
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struct nh_group *spare; /* spare group for removals */
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u16 num_nh;
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bool mpath;
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bool has_v4;
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struct nh_grp_entry nh_entries[0];
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};
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struct nexthop {
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struct rb_node rb_node; /* entry on netns rbtree */
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struct list_head fi_list; /* v4 entries using nh */
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struct list_head f6i_list; /* v6 entries using nh */
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struct list_head grp_list; /* nh group entries using this nh */
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struct net *net;
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u32 id;
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u8 protocol; /* app managing this nh */
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u8 nh_flags;
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bool is_group;
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refcount_t refcnt;
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struct rcu_head rcu;
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union {
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struct nh_info __rcu *nh_info;
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struct nh_group __rcu *nh_grp;
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};
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};
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/* caller is holding rcu or rtnl; no reference taken to nexthop */
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struct nexthop *nexthop_find_by_id(struct net *net, u32 id);
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void nexthop_free_rcu(struct rcu_head *head);
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static inline bool nexthop_get(struct nexthop *nh)
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{
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return refcount_inc_not_zero(&nh->refcnt);
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}
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static inline void nexthop_put(struct nexthop *nh)
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{
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if (refcount_dec_and_test(&nh->refcnt))
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call_rcu(&nh->rcu, nexthop_free_rcu);
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}
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static inline bool nexthop_cmp(const struct nexthop *nh1,
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const struct nexthop *nh2)
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{
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return nh1 == nh2;
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}
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static inline bool nexthop_is_multipath(const struct nexthop *nh)
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{
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if (nh->is_group) {
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struct nh_group *nh_grp;
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nh_grp = rcu_dereference_rtnl(nh->nh_grp);
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return nh_grp->mpath;
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}
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return false;
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}
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struct nexthop *nexthop_select_path(struct nexthop *nh, int hash);
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static inline unsigned int nexthop_num_path(const struct nexthop *nh)
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{
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unsigned int rc = 1;
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if (nh->is_group) {
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struct nh_group *nh_grp;
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nh_grp = rcu_dereference_rtnl(nh->nh_grp);
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if (nh_grp->mpath)
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rc = nh_grp->num_nh;
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}
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return rc;
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}
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static inline
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struct nexthop *nexthop_mpath_select(const struct nh_group *nhg, int nhsel)
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{
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/* for_nexthops macros in fib_semantics.c grabs a pointer to
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* the nexthop before checking nhsel
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*/
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if (nhsel >= nhg->num_nh)
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return NULL;
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return nhg->nh_entries[nhsel].nh;
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}
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static inline
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int nexthop_mpath_fill_node(struct sk_buff *skb, struct nexthop *nh,
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u8 rt_family)
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{
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struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
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int i;
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for (i = 0; i < nhg->num_nh; i++) {
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struct nexthop *nhe = nhg->nh_entries[i].nh;
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struct nh_info *nhi = rcu_dereference_rtnl(nhe->nh_info);
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struct fib_nh_common *nhc = &nhi->fib_nhc;
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int weight = nhg->nh_entries[i].weight;
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if (fib_add_nexthop(skb, nhc, weight, rt_family, 0) < 0)
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return -EMSGSIZE;
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}
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return 0;
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}
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/* called with rcu lock */
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static inline bool nexthop_is_blackhole(const struct nexthop *nh)
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{
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const struct nh_info *nhi;
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if (nh->is_group) {
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struct nh_group *nh_grp;
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nh_grp = rcu_dereference_rtnl(nh->nh_grp);
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if (nh_grp->num_nh > 1)
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return false;
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nh = nh_grp->nh_entries[0].nh;
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}
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nhi = rcu_dereference_rtnl(nh->nh_info);
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return nhi->reject_nh;
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}
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static inline void nexthop_path_fib_result(struct fib_result *res, int hash)
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{
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struct nh_info *nhi;
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struct nexthop *nh;
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nh = nexthop_select_path(res->fi->nh, hash);
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nhi = rcu_dereference(nh->nh_info);
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res->nhc = &nhi->fib_nhc;
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}
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/* called with rcu read lock or rtnl held */
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static inline
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struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel)
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{
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struct nh_info *nhi;
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BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0);
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BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0);
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if (nh->is_group) {
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struct nh_group *nh_grp;
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nh_grp = rcu_dereference_rtnl(nh->nh_grp);
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if (nh_grp->mpath) {
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nh = nexthop_mpath_select(nh_grp, nhsel);
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if (!nh)
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return NULL;
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}
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}
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nhi = rcu_dereference_rtnl(nh->nh_info);
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return &nhi->fib_nhc;
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}
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static inline bool nexthop_uses_dev(const struct nexthop *nh,
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const struct net_device *dev)
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{
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struct nh_info *nhi;
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if (nh->is_group) {
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struct nh_group *nhg = rcu_dereference(nh->nh_grp);
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int i;
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for (i = 0; i < nhg->num_nh; i++) {
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struct nexthop *nhe = nhg->nh_entries[i].nh;
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nhi = rcu_dereference(nhe->nh_info);
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if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
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return true;
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}
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} else {
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nhi = rcu_dereference(nh->nh_info);
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if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
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return true;
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}
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return false;
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}
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static inline unsigned int fib_info_num_path(const struct fib_info *fi)
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{
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if (unlikely(fi->nh))
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return nexthop_num_path(fi->nh);
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return fi->fib_nhs;
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}
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int fib_check_nexthop(struct nexthop *nh, u8 scope,
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struct netlink_ext_ack *extack);
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static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel)
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{
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if (unlikely(fi->nh))
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return nexthop_fib_nhc(fi->nh, nhsel);
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return &fi->fib_nh[nhsel].nh_common;
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}
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/* only used when fib_nh is built into fib_info */
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static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel)
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{
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WARN_ON(fi->nh);
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return &fi->fib_nh[nhsel];
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}
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/*
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* IPv6 variants
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*/
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int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
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struct netlink_ext_ack *extack);
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/* Caller should either hold rcu_read_lock(), or RTNL. */
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static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh)
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{
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struct nh_info *nhi;
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if (nh->is_group) {
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struct nh_group *nh_grp;
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nh_grp = rcu_dereference_rtnl(nh->nh_grp);
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nh = nexthop_mpath_select(nh_grp, 0);
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if (!nh)
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return NULL;
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}
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nhi = rcu_dereference_rtnl(nh->nh_info);
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if (nhi->family == AF_INET6)
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return &nhi->fib6_nh;
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return NULL;
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}
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/* Variant of nexthop_fib6_nh().
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* Caller should either hold rcu_read_lock_bh(), or RTNL.
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*/
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static inline struct fib6_nh *nexthop_fib6_nh_bh(struct nexthop *nh)
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{
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struct nh_info *nhi;
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if (nh->is_group) {
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struct nh_group *nh_grp;
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nh_grp = rcu_dereference_bh_rtnl(nh->nh_grp);
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nh = nexthop_mpath_select(nh_grp, 0);
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if (!nh)
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return NULL;
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}
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nhi = rcu_dereference_bh_rtnl(nh->nh_info);
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if (nhi->family == AF_INET6)
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return &nhi->fib6_nh;
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return NULL;
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}
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static inline struct net_device *fib6_info_nh_dev(struct fib6_info *f6i)
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{
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struct fib6_nh *fib6_nh;
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fib6_nh = f6i->nh ? nexthop_fib6_nh(f6i->nh) : f6i->fib6_nh;
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return fib6_nh->fib_nh_dev;
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}
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static inline void nexthop_path_fib6_result(struct fib6_result *res, int hash)
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{
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struct nexthop *nh = res->f6i->nh;
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struct nh_info *nhi;
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nh = nexthop_select_path(nh, hash);
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nhi = rcu_dereference_rtnl(nh->nh_info);
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if (nhi->reject_nh) {
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res->fib6_type = RTN_BLACKHOLE;
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res->fib6_flags |= RTF_REJECT;
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res->nh = nexthop_fib6_nh(nh);
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} else {
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res->nh = &nhi->fib6_nh;
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}
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}
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int nexthop_for_each_fib6_nh(struct nexthop *nh,
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int (*cb)(struct fib6_nh *nh, void *arg),
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void *arg);
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#endif
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