include/net/nexthop.h - linux - Git at Google

 /* 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 {
 	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 (nexthop_is_multipath(nh)) {
 		struct nh_group *nh_grp;

 		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
 		rc = nh_grp->num_nh;
 	}

 	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,
 			    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)
 			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;
 }

 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 (nexthop_is_multipath(nh)) {
 		nh = nexthop_mpath_select(nh, nhsel);
 		if (!nh)
 			return NULL;
 	}

 	nhi = rcu_dereference_rtnl(nh->nh_info);
 	return &nhi->fib_nhc;
 }

 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);

 static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh)
 {
 	struct nh_info *nhi;

 	if (nexthop_is_multipath(nh)) {
 		nh = nexthop_mpath_select(nh, 0);
 		if (!nh)
 			return NULL;
 	}

 	nhi = rcu_dereference_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
	/* 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 {
	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 (nexthop_is_multipath(nh)) {
	struct nh_group *nh_grp;

	nh_grp = rcu_dereference_rtnl(nh->nh_grp);
	rc = nh_grp->num_nh;
	}

	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,
	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)
	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;
	}

	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 (nexthop_is_multipath(nh)) {
	nh = nexthop_mpath_select(nh, nhsel);
	if (!nh)
	return NULL;
	}

	nhi = rcu_dereference_rtnl(nh->nh_info);
	return &nhi->fib_nhc;
	}

	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);

	static inline struct fib6_nh nexthop_fib6_nh(struct nexthop nh)
	{
	struct nh_info *nhi;

	if (nexthop_is_multipath(nh)) {
	nh = nexthop_mpath_select(nh, 0);
	if (!nh)
	return NULL;
	}

	nhi = rcu_dereference_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