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Date: Thu, 21 Apr 2022 01:21:37 +0200
From: Guillaume Nault <gnault@...hat.com>
To: David Miller <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: netdev@...r.kernel.org,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
David Ahern <dsahern@...nel.org>
Subject: [PATCH net-next 3/3] 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: Guillaume Nault <gnault@...hat.com>
---
net/ipv4/route.c | 37 +++++++++++++++++--------------------
1 file changed, 17 insertions(+), 20 deletions(-)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index d8f82c0ac132..ffbe2e4f8c89 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -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);
--
2.21.3
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