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/* 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/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;
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;
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 {
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;
};
};
/* 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_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;
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
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