Commit 4c7e8084 authored by David Ahern's avatar David Ahern Committed by David S. Miller
Browse files

ipv4: Plumb support for nexthop object in a fib_info 



Add 'struct nexthop' and nh_list list_head to fib_info. nh_list is the
fib_info side of the nexthop <-> fib_info relationship.

Add fi_list list_head to 'struct nexthop' to track fib_info entries
using a nexthop instance. Add __remove_nexthop_fib and add it to
__remove_nexthop to walk the new list_head and mark those fib entries
as dead when the nexthop is deleted.

Add a few nexthop helpers for use when a nexthop is added to fib_info:
- nexthop_cmp to determine if 2 nexthops are the same
- nexthop_path_fib_result to select a path for a multipath
  'struct nexthop'
- nexthop_fib_nhc to select a specific fib_nh_common within a
  multipath 'struct nexthop'

Update existing fib_info_nhc to use nexthop_fib_nhc if a fib_info uses
a 'struct nexthop', and mark fib_info_nh as only used for the non-nexthop
case.

Update the fib_info functions to check for fi->nh and take a different
path as needed:
- free_fib_info_rcu - put the nexthop object reference
- fib_release_info - remove the fib_info from the nexthop's fi_list
- nh_comp - use nexthop_cmp when either fib_info references a nexthop
  object
- fib_info_hashfn - use the nexthop id for the hashing vs the oif of
  each fib_nh in a fib_info
- fib_nlmsg_size - add space for the RTA_NH_ID attribute
- fib_create_info - verify nexthop reference can be taken, verify
  nexthop spec is valid for fib entry, and add fib_info to fi_list for
  a nexthop
- fib_select_multipath - use the new nexthop_path_fib_result to select a
  path when nexthop objects are used
- fib_table_lookup - if the 'struct nexthop' is a blackhole nexthop, treat
  it the same as a fib entry using 'blackhole'

The bulk of the changes are in fib_semantics.c and most of that is
moving the existing change_nexthops into an else branch.

Update the nexthop code to walk fi_list on a nexthop deleted to remove
fib entries referencing it.

Signed-off-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent dcb1ecb5

include/net/ip_fib.h

+4 −0
Original line number Diff line number Diff line
@@ -129,9 +129,12 @@ struct fib_nh { 
 * This structure contains data shared by many of routes.

 */



struct nexthop;



struct fib_info {

	struct hlist_node	fib_hash;

	struct hlist_node	fib_lhash;

	struct list_head	nh_list;

	struct net		*fib_net;

	int			fib_treeref;

	refcount_t		fib_clntref;
@@ -151,6 +154,7 @@ struct fib_info { 
	int			fib_nhs;

	bool			fib_nh_is_v6;

	bool			nh_updated;

	struct nexthop		*nh;

	struct rcu_head		rcu;

	struct fib_nh		fib_nh[0];

};

include/net/nexthop.h

+48 −0
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ struct nh_group { 


struct nexthop {

	struct rb_node		rb_node;    /* entry on netns rbtree */

	struct list_head	fi_list;    /* v4 entries using nh */

	struct list_head	grp_list;   /* nh group entries using this nh */

	struct net		*net;
@@ -110,6 +111,12 @@ static inline void nexthop_put(struct nexthop *nh) 
		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) {
@@ -193,18 +200,59 @@ static inline bool nexthop_is_blackhole(const struct nexthop *nh) 
	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];

}

#endif

net/ipv4/fib_semantics.c

+106 −36
Original line number Diff line number Diff line
@@ -236,9 +236,13 @@ static void free_fib_info_rcu(struct rcu_head *head) 
{

	struct fib_info *fi = container_of(head, struct fib_info, rcu);



	if (fi->nh) {

		nexthop_put(fi->nh);

	} else {

		change_nexthops(fi) {

			fib_nh_release(fi->fib_net, nexthop_nh);

		} endfor_nexthops(fi);

	}



	ip_fib_metrics_put(fi->fib_metrics);
@@ -264,11 +268,15 @@ void fib_release_info(struct fib_info *fi) 
		hlist_del(&fi->fib_hash);

		if (fi->fib_prefsrc)

			hlist_del(&fi->fib_lhash);

		if (fi->nh) {

			list_del(&fi->nh_list);

		} else {

			change_nexthops(fi) {

				if (!nexthop_nh->fib_nh_dev)

					continue;

				hlist_del(&nexthop_nh->nh_hash);

			} endfor_nexthops(fi)

		}

		fi->fib_dead = 1;

		fib_info_put(fi);

	}
@@ -279,6 +287,12 @@ static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi) 
{

	const struct fib_nh *onh;



	if (fi->nh || ofi->nh)

		return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;



	if (ofi->fib_nhs == 0)

		return 0;



	for_nexthops(fi) {

		onh = fib_info_nh(ofi, nhsel);
@@ -323,9 +337,14 @@ static inline unsigned int fib_info_hashfn(const struct fib_info *fi) 
	val ^= (fi->fib_protocol << 8) | fi->fib_scope;

	val ^= (__force u32)fi->fib_prefsrc;

	val ^= fi->fib_priority;



	if (fi->nh) {

		val ^= fib_devindex_hashfn(fi->nh->id);

	} else {

		for_nexthops(fi) {

			val ^= fib_devindex_hashfn(nh->fib_nh_oif);

		} endfor_nexthops(fi)

	}



	return (val ^ (val >> 7) ^ (val >> 12)) & mask;

}
@@ -352,7 +371,7 @@ static struct fib_info *fib_find_info(struct fib_info *nfi) 
		    memcmp(nfi->fib_metrics, fi->fib_metrics,

			   sizeof(u32) * RTAX_MAX) == 0 &&

		    !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&

		    (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))

		    nh_comp(fi, nfi) == 0)

			return fi;

	}
@@ -399,6 +418,9 @@ static inline size_t fib_nlmsg_size(struct fib_info *fi) 
	/* space for nested metrics */

	payload += nla_total_size((RTAX_MAX * nla_total_size(4)));



	if (fi->nh)

		payload += nla_total_size(4); /* RTA_NH_ID */



	if (nhs) {

		size_t nh_encapsize = 0;

		/* Also handles the special case nhs == 1 */
@@ -585,6 +607,7 @@ static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining, 
	return nhs;

}



/* only called when fib_nh is integrated into fib_info */

static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,

		       int remaining, struct fib_config *cfg,

		       struct netlink_ext_ack *extack)
@@ -683,6 +706,7 @@ errout: 
	return ret;

}



/* only called when fib_nh is integrated into fib_info */

static void fib_rebalance(struct fib_info *fi)

{

	int total;
@@ -1262,6 +1286,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg, 
{

	int err;

	struct fib_info *fi = NULL;

	struct nexthop *nh = NULL;

	struct fib_info *ofi;

	int nhs = 1;

	struct net *net = cfg->fc_nlinfo.nl_net;
@@ -1333,14 +1358,25 @@ struct fib_info *fib_create_info(struct fib_config *cfg, 
	fi->fib_tb_id = cfg->fc_table;



	fi->fib_nhs = nhs;

	if (nh) {

		if (!nexthop_get(nh)) {

			NL_SET_ERR_MSG(extack, "Nexthop has been deleted");

			err = -EINVAL;

		} else {

			err = 0;

			fi->nh = nh;

		}

	} else {

		change_nexthops(fi) {

			nexthop_nh->nh_parent = fi;

		} endfor_nexthops(fi)



		if (cfg->fc_mp)

		err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);

			err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,

					  extack);

		else

			err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);

	}



	if (err != 0)

		goto failure;
@@ -1371,7 +1407,11 @@ struct fib_info *fib_create_info(struct fib_config *cfg, 
		goto err_inval;

	}



	if (cfg->fc_scope == RT_SCOPE_HOST) {

	if (fi->nh) {

		err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);

		if (err)

			goto failure;

	} else if (cfg->fc_scope == RT_SCOPE_HOST) {

		struct fib_nh *nh = fi->fib_nh;



		/* Local address is added. */
@@ -1411,6 +1451,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg, 
		goto err_inval;

	}



	if (!fi->nh) {

		change_nexthops(fi) {

			fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,

						  fi->fib_scope);
@@ -1419,6 +1460,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg, 
		} endfor_nexthops(fi)



		fib_rebalance(fi);

	}



link_it:

	ofi = fib_find_info(fi);
@@ -1440,6 +1482,9 @@ link_it: 
		head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];

		hlist_add_head(&fi->fib_lhash, head);

	}

	if (fi->nh) {

		list_add(&fi->nh_list, &nh->fi_list);

	} else {

		change_nexthops(fi) {

			struct hlist_head *head;

			unsigned int hash;
@@ -1450,6 +1495,7 @@ link_it: 
			head = &fib_info_devhash[hash];

			hlist_add_head(&nexthop_nh->nh_hash, head);

		} endfor_nexthops(fi)

	}

	spin_unlock_bh(&fib_info_lock);

	return fi;
@@ -1576,6 +1622,12 @@ static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 
	if (!mp)

		goto nla_put_failure;



	if (unlikely(fi->nh)) {

		if (nexthop_mpath_fill_node(skb, fi->nh) < 0)

			goto nla_put_failure;

		goto mp_end;

	}



	for_nexthops(fi) {

		if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight) < 0)

			goto nla_put_failure;
@@ -1586,6 +1638,7 @@ static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi) 
#endif

	} endfor_nexthops(fi);



mp_end:

	nla_nest_end(skb, mp);



	return 0;
@@ -1640,6 +1693,14 @@ int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, 
	if (fi->fib_prefsrc &&

	    nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))

		goto nla_put_failure;



	if (fi->nh) {

		if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))

			goto nla_put_failure;

		if (nexthop_is_blackhole(fi->nh))

			rtm->rtm_type = RTN_BLACKHOLE;

	}



	if (nhs == 1) {

		const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);

		unsigned char flags = 0;
@@ -1784,6 +1845,8 @@ void fib_sync_mtu(struct net_device *dev, u32 orig_mtu) 
 * NETDEV_DOWN        0     LINKDOWN|DEAD   Link down, not for scope host

 * NETDEV_DOWN        1     LINKDOWN|DEAD   Last address removed

 * NETDEV_UNREGISTER  1     LINKDOWN|DEAD   Device removed

 *

 * only used when fib_nh is built into fib_info

 */

int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)

{
@@ -1931,6 +1994,8 @@ out: 
/*

 * Dead device goes up. We wake up dead nexthops.

 * It takes sense only on multipath routes.

 *

 * only used when fib_nh is built into fib_info

 */

int fib_sync_up(struct net_device *dev, unsigned char nh_flags)

{
@@ -2025,6 +2090,11 @@ void fib_select_multipath(struct fib_result *res, int hash) 
	struct net *net = fi->fib_net;

	bool first = false;



	if (unlikely(res->fi->nh)) {

		nexthop_path_fib_result(res, hash);

		return;

	}



	change_nexthops(fi) {

		if (net->ipv4.sysctl_fib_multipath_use_neigh) {

			if (!fib_good_nh(nexthop_nh))

net/ipv4/fib_trie.c

+7 −0
Original line number Diff line number Diff line
@@ -1461,6 +1461,7 @@ found: 
		fib_alias_accessed(fa);

		err = fib_props[fa->fa_type].error;

		if (unlikely(err < 0)) {

out_reject:

#ifdef CONFIG_IP_FIB_TRIE_STATS

			this_cpu_inc(stats->semantic_match_passed);

#endif
@@ -1469,6 +1470,12 @@ found: 
		}

		if (fi->fib_flags & RTNH_F_DEAD)

			continue;



		if (unlikely(fi->nh && nexthop_is_blackhole(fi->nh))) {

			err = fib_props[RTN_BLACKHOLE].error;

			goto out_reject;

		}



		for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {

			struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);

net/ipv4/nexthop.c

+64 −0
Original line number Diff line number Diff line
@@ -105,6 +105,7 @@ static struct nexthop *nexthop_alloc(void) 


	nh = kzalloc(sizeof(struct nexthop), GFP_KERNEL);

	if (nh) {

		INIT_LIST_HEAD(&nh->fi_list);

		INIT_LIST_HEAD(&nh->grp_list);

	}

	return nh;
@@ -515,6 +516,54 @@ struct nexthop *nexthop_select_path(struct nexthop *nh, int hash) 
}

EXPORT_SYMBOL_GPL(nexthop_select_path);



static int nexthop_check_scope(struct nexthop *nh, u8 scope,

			       struct netlink_ext_ack *extack)

{

	struct nh_info *nhi;



	nhi = rtnl_dereference(nh->nh_info);

	if (scope == RT_SCOPE_HOST && nhi->fib_nhc.nhc_gw_family) {

		NL_SET_ERR_MSG(extack,

			       "Route with host scope can not have a gateway");

		return -EINVAL;

	}



	if (nhi->fib_nhc.nhc_flags & RTNH_F_ONLINK && scope >= RT_SCOPE_LINK) {

		NL_SET_ERR_MSG(extack, "Scope mismatch with nexthop");

		return -EINVAL;

	}



	return 0;

}



/* Invoked by fib add code to verify nexthop by id is ok with

 * config for prefix; parts of fib_check_nh not done when nexthop

 * object is used.

 */

int fib_check_nexthop(struct nexthop *nh, u8 scope,

		      struct netlink_ext_ack *extack)

{

	int err = 0;



	if (nh->is_group) {

		struct nh_group *nhg;



		if (scope == RT_SCOPE_HOST) {

			NL_SET_ERR_MSG(extack, "Route with host scope can not have multiple nexthops");

			err = -EINVAL;

			goto out;

		}



		nhg = rtnl_dereference(nh->nh_grp);

		/* all nexthops in a group have the same scope */

		err = nexthop_check_scope(nhg->nh_entries[0].nh, scope, extack);

	} else {

		err = nexthop_check_scope(nh, scope, extack);

	}

out:

	return err;

}



static void nh_group_rebalance(struct nh_group *nhg)

{

	int total = 0;
@@ -607,9 +656,24 @@ static void remove_nexthop_group(struct nexthop *nh, struct nl_info *nlinfo) 
	}

}



static void __remove_nexthop_fib(struct net *net, struct nexthop *nh)

{

	bool do_flush = false;

	struct fib_info *fi;



	list_for_each_entry(fi, &nh->fi_list, nh_list) {

		fi->fib_flags |= RTNH_F_DEAD;

		do_flush = true;

	}

	if (do_flush)

		fib_flush(net);

}



static void __remove_nexthop(struct net *net, struct nexthop *nh,

			     struct nl_info *nlinfo)

{

	__remove_nexthop_fib(net, nh);



	if (nh->is_group) {

		remove_nexthop_group(nh, nlinfo);

	} else {

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