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Commit 5510cdf7 authored by David Ahern's avatar David Ahern Committed by David S. Miller
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net: ipv4: refactor ip_route_input_noref 



A later patch wants access to the fib result on an input route lookup
with the rcu lock held. Refactor ip_route_input_noref pushing the logic
between rcu_read_lock ... rcu_read_unlock into a new helper that takes
the fib_result as an input arg.

Signed-off-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3abd1ade

include/net/route.h

+3 −0
Original line number Diff line number Diff line
@@ -178,6 +178,9 @@ static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4 


int ip_route_input_noref(struct sk_buff *skb, __be32 dst, __be32 src,

			 u8 tos, struct net_device *devin);

int ip_route_input_rcu(struct sk_buff *skb, __be32 dst, __be32 src,

		       u8 tos, struct net_device *devin,

		       struct fib_result *res);



static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,

				 u8 tos, struct net_device *devin)

net/ipv4/route.c

+37 −29
Original line number Diff line number Diff line
@@ -1852,9 +1852,9 @@ static int ip_mkroute_input(struct sk_buff *skb, 
 */



static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,

			       u8 tos, struct net_device *dev)

			       u8 tos, struct net_device *dev,

			       struct fib_result *res)

{

	struct fib_result res;

	struct in_device *in_dev = __in_dev_get_rcu(dev);

	struct ip_tunnel_info *tun_info;

	struct flowi4	fl4;
@@ -1884,8 +1884,8 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
	if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))

		goto martian_source;



	res.fi = NULL;

	res.table = NULL;

	res->fi = NULL;

	res->table = NULL;

	if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))

		goto brd_input;
@@ -1921,17 +1921,17 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
	fl4.daddr = daddr;

	fl4.saddr = saddr;

	fl4.flowi4_uid = sock_net_uid(net, NULL);

	err = fib_lookup(net, &fl4, &res, 0);

	err = fib_lookup(net, &fl4, res, 0);

	if (err != 0) {

		if (!IN_DEV_FORWARD(in_dev))

			err = -EHOSTUNREACH;

		goto no_route;

	}



	if (res.type == RTN_BROADCAST)

	if (res->type == RTN_BROADCAST)

		goto brd_input;



	if (res.type == RTN_LOCAL) {

	if (res->type == RTN_LOCAL) {

		err = fib_validate_source(skb, saddr, daddr, tos,

					  0, dev, in_dev, &itag);

		if (err < 0)
@@ -1943,10 +1943,10 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
		err = -EHOSTUNREACH;

		goto no_route;

	}

	if (res.type != RTN_UNICAST)

	if (res->type != RTN_UNICAST)

		goto martian_destination;



	err = ip_mkroute_input(skb, &res, in_dev, daddr, saddr, tos);

	err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos);

out:	return err;



brd_input:
@@ -1960,14 +1960,14 @@ out: return err; 
			goto martian_source;

	}

	flags |= RTCF_BROADCAST;

	res.type = RTN_BROADCAST;

	res->type = RTN_BROADCAST;

	RT_CACHE_STAT_INC(in_brd);



local_input:

	do_cache = false;

	if (res.fi) {

	if (res->fi) {

		if (!itag) {

			rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);

			rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);

			if (rt_cache_valid(rth)) {

				skb_dst_set_noref(skb, &rth->dst);

				err = 0;
@@ -1978,7 +1978,7 @@ out: return err; 
	}



	rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev,

			   flags | RTCF_LOCAL, res.type,

			   flags | RTCF_LOCAL, res->type,

			   IN_DEV_CONF_GET(in_dev, NOPOLICY), false, do_cache);

	if (!rth)

		goto e_nobufs;
@@ -1988,18 +1988,18 @@ out: return err; 
	rth->dst.tclassid = itag;

#endif

	rth->rt_is_input = 1;

	if (res.table)

		rth->rt_table_id = res.table->tb_id;

	if (res->table)

		rth->rt_table_id = res->table->tb_id;



	RT_CACHE_STAT_INC(in_slow_tot);

	if (res.type == RTN_UNREACHABLE) {

	if (res->type == RTN_UNREACHABLE) {

		rth->dst.input= ip_error;

		rth->dst.error= -err;

		rth->rt_flags 	&= ~RTCF_LOCAL;

	}



	if (do_cache) {

		struct fib_nh *nh = &FIB_RES_NH(res);

		struct fib_nh *nh = &FIB_RES_NH(*res);



		rth->dst.lwtstate = lwtstate_get(nh->nh_lwtstate);

		if (lwtunnel_input_redirect(rth->dst.lwtstate)) {
@@ -2019,9 +2019,9 @@ out: return err; 


no_route:

	RT_CACHE_STAT_INC(in_no_route);

	res.type = RTN_UNREACHABLE;

	res.fi = NULL;

	res.table = NULL;

	res->type = RTN_UNREACHABLE;

	res->fi = NULL;

	res->table = NULL;

	goto local_input;



	/*
@@ -2051,11 +2051,22 @@ out: return err; 
int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,

			 u8 tos, struct net_device *dev)

{

	int res;

	struct fib_result res;

	int err;



	tos &= IPTOS_RT_MASK;

	rcu_read_lock();

	err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);

	rcu_read_unlock();



	return err;

}

EXPORT_SYMBOL(ip_route_input_noref);



/* called with rcu_read_lock held */

int ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr,

		       u8 tos, struct net_device *dev, struct fib_result *res)

{

	/* Multicast recognition logic is moved from route cache to here.

	   The problem was that too many Ethernet cards have broken/missing

	   hardware multicast filters :-( As result the host on multicasting
@@ -2070,6 +2081,7 @@ int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
	if (ipv4_is_multicast(daddr)) {

		struct in_device *in_dev = __in_dev_get_rcu(dev);

		int our = 0;

		int err = -EINVAL;



		if (in_dev)

			our = ip_check_mc_rcu(in_dev, daddr, saddr,
@@ -2085,7 +2097,6 @@ int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
						      ip_hdr(skb)->protocol);

		}



		res = -EINVAL;

		if (our

#ifdef CONFIG_IP_MROUTE

			||
@@ -2093,17 +2104,14 @@ int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
		     IN_DEV_MFORWARD(in_dev))

#endif

		   ) {

			res = ip_route_input_mc(skb, daddr, saddr,

			err = ip_route_input_mc(skb, daddr, saddr,

						tos, dev, our);

		}

		rcu_read_unlock();

		return res;

		return err;

	}

	res = ip_route_input_slow(skb, daddr, saddr, tos, dev);

	rcu_read_unlock();

	return res;



	return ip_route_input_slow(skb, daddr, saddr, tos, dev, res);

}

EXPORT_SYMBOL(ip_route_input_noref);



/* called with rcu_read_lock() */

static struct rtable *__mkroute_output(const struct fib_result *res,