Commit b1ad4138 authored by Guillaume Nault's avatar Guillaume Nault Committed by David S. Miller
Browse files

ipv4: Initialise ->flowi4_scope properly in ICMP handlers. 



All the *_redirect() and *_update_pmtu() functions initialise their
struct flowi4 variable with either __build_flow_key() or
build_sk_flow_key(). When sk is provided, these functions use
RT_CONN_FLAGS() to set ->flowi4_tos and always use RT_SCOPE_UNIVERSE
for ->flowi4_scope. Then they rely on ip_rt_fix_tos() to adjust the
scope based on the RTO_ONLINK bit and to mask the tos with
IPTOS_RT_MASK.

This patch modifies __build_flow_key() and build_sk_flow_key() to
properly initialise ->flowi4_tos and ->flowi4_scope, so that the
ICMP redirects and PMTU handlers don't need an extra call to
ip_rt_fix_tos() before doing a fib lookup. That is, we:

  * Drop RT_CONN_FLAGS(): use ip_sock_rt_tos() and ip_sock_rt_scope()
    instead, so that we don't have to rely on ip_rt_fix_tos() to adjust
    the scope anymore.

  * Apply IPTOS_RT_MASK to the tos, so that we don't need
    ip_rt_fix_tos() to do it for us.

  * Drop the ip_rt_fix_tos() calls that now become useless.

The only remaining ip_rt_fix_tos() caller is ip_route_output_key_hash()
which needs it as long as external callers still use the RTO_ONLINK
flag.

Note:
  This patch also drops some useless RT_TOS() calls as IPTOS_RT_MASK is
  a stronger mask.

Signed-off-by: default avatarGuillaume Nault <gnault@redhat.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 67e1e2f4

net/ipv4/route.c

+17 −20
Original line number Diff line number Diff line
@@ -508,23 +508,24 @@ static void ip_rt_fix_tos(struct flowi4 *fl4) 
}



static void __build_flow_key(const struct net *net, struct flowi4 *fl4,

			     const struct sock *sk,

			     const struct iphdr *iph,

			     int oif, u8 tos,

			     u8 prot, u32 mark, int flow_flags)

			     const struct sock *sk, const struct iphdr *iph,

			     int oif, __u8 tos, u8 prot, u32 mark,

			     int flow_flags)

{

	__u8 scope = RT_SCOPE_UNIVERSE;



	if (sk) {

		const struct inet_sock *inet = inet_sk(sk);



		oif = sk->sk_bound_dev_if;

		mark = sk->sk_mark;

		tos = RT_CONN_FLAGS(sk);

		tos = ip_sock_rt_tos(sk);

		scope = ip_sock_rt_scope(sk);

		prot = inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol;

	}

	flowi4_init_output(fl4, oif, mark, tos,

			   RT_SCOPE_UNIVERSE, prot,

			   flow_flags,

			   iph->daddr, iph->saddr, 0, 0,



	flowi4_init_output(fl4, oif, mark, tos & IPTOS_RT_MASK, scope,

			   prot, flow_flags, iph->daddr, iph->saddr, 0, 0,

			   sock_net_uid(net, sk));

}
@@ -534,9 +535,9 @@ static void build_skb_flow_key(struct flowi4 *fl4, const struct sk_buff *skb, 
	const struct net *net = dev_net(skb->dev);

	const struct iphdr *iph = ip_hdr(skb);

	int oif = skb->dev->ifindex;

	u8 tos = RT_TOS(iph->tos);

	u8 prot = iph->protocol;

	u32 mark = skb->mark;

	__u8 tos = iph->tos;



	__build_flow_key(net, fl4, sk, iph, oif, tos, prot, mark, 0);

}
@@ -552,7 +553,8 @@ static void build_sk_flow_key(struct flowi4 *fl4, const struct sock *sk) 
	if (inet_opt && inet_opt->opt.srr)

		daddr = inet_opt->opt.faddr;

	flowi4_init_output(fl4, sk->sk_bound_dev_if, sk->sk_mark,

			   RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,

			   ip_sock_rt_tos(sk) & IPTOS_RT_MASK,

			   ip_sock_rt_scope(sk),

			   inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,

			   inet_sk_flowi_flags(sk),

			   daddr, inet->inet_saddr, 0, 0, sk->sk_uid);
@@ -825,14 +827,13 @@ static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buf 
	const struct iphdr *iph = (const struct iphdr *) skb->data;

	struct net *net = dev_net(skb->dev);

	int oif = skb->dev->ifindex;

	u8 tos = RT_TOS(iph->tos);

	u8 prot = iph->protocol;

	u32 mark = skb->mark;

	__u8 tos = iph->tos;



	rt = (struct rtable *) dst;



	__build_flow_key(net, &fl4, sk, iph, oif, tos, prot, mark, 0);

	ip_rt_fix_tos(&fl4);

	__ip_do_redirect(rt, skb, &fl4, true);

}
@@ -1061,7 +1062,6 @@ static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk, 
	struct flowi4 fl4;



	ip_rt_build_flow_key(&fl4, sk, skb);

	ip_rt_fix_tos(&fl4);



	/* Don't make lookup fail for bridged encapsulations */

	if (skb && netif_is_any_bridge_port(skb->dev))
@@ -1078,8 +1078,8 @@ void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, 
	struct rtable *rt;

	u32 mark = IP4_REPLY_MARK(net, skb->mark);



	__build_flow_key(net, &fl4, NULL, iph, oif,

			 RT_TOS(iph->tos), protocol, mark, 0);

	__build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, mark,

			 0);

	rt = __ip_route_output_key(net, &fl4);

	if (!IS_ERR(rt)) {

		__ip_rt_update_pmtu(rt, &fl4, mtu);
@@ -1136,8 +1136,6 @@ void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu) 
			goto out;



		new = true;

	} else {

		ip_rt_fix_tos(&fl4);

	}



	__ip_rt_update_pmtu((struct rtable *)xfrm_dst_path(&rt->dst), &fl4, mtu);
@@ -1169,8 +1167,7 @@ void ipv4_redirect(struct sk_buff *skb, struct net *net, 
	struct flowi4 fl4;

	struct rtable *rt;



	__build_flow_key(net, &fl4, NULL, iph, oif,

			 RT_TOS(iph->tos), protocol, 0, 0);

	__build_flow_key(net, &fl4, NULL, iph, oif, iph->tos, protocol, 0, 0);

	rt = __ip_route_output_key(net, &fl4);

	if (!IS_ERR(rt)) {

		__ip_do_redirect(rt, skb, &fl4, false);