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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/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;
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 {
struct nh_group *spare; /* spare group for removals */
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 fi_list; /* v4 entries using nh */
struct list_head f6i_list; /* v6 entries using 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;
};
};
/* 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_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;
}
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);
#endif
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