Commit 65a55aa7 authored by Guillaume Nault's avatar Guillaume Nault Committed by Jakub Kicinski
Browse files

ipv4: Prepare inet_rtm_getroute() to .flowi4_tos conversion. 



Store rtm->rtm_tos in a dscp_t variable, which can then be used for
setting fl4.flowi4_tos and also be passed as parameter of
ip_route_input_rcu().

The .flowi4_tos field is going to be converted to dscp_t to ensure ECN
bits aren't erroneously taken into account during route lookups. Having
a dscp_t variable available will simplify that conversion, as we'll
just have to drop the inet_dscp_to_dsfield() call.

Note that we can't just convert rtm->rtm_tos to dscp_t because this
structure is exported to user space.

Signed-off-by: default avatarGuillaume Nault <gnault@redhat.com>
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/7bc1c7dc47ad1393569095d334521fae59af5bc7.1736944951.git.gnault@redhat.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 2c77bcb3

net/ipv4/route.c

+5 −4
Original line number Diff line number Diff line
@@ -3270,6 +3270,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 
	struct flowi4 fl4 = {};

	__be32 dst = 0;

	__be32 src = 0;

	dscp_t dscp;

	kuid_t uid;

	u32 iif;

	int err;
@@ -3284,6 +3285,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 
	dst = nla_get_in_addr_default(tb[RTA_DST], 0);

	iif = nla_get_u32_default(tb[RTA_IIF], 0);

	mark = nla_get_u32_default(tb[RTA_MARK], 0);

	dscp = inet_dsfield_to_dscp(rtm->rtm_tos);

	if (tb[RTA_UID])

		uid = make_kuid(current_user_ns(), nla_get_u32(tb[RTA_UID]));

	else
@@ -3308,7 +3310,7 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 


	fl4.daddr = dst;

	fl4.saddr = src;

	fl4.flowi4_tos = rtm->rtm_tos & INET_DSCP_MASK;

	fl4.flowi4_tos = inet_dscp_to_dsfield(dscp);

	fl4.flowi4_oif = nla_get_u32_default(tb[RTA_OIF], 0);

	fl4.flowi4_mark = mark;

	fl4.flowi4_uid = uid;
@@ -3332,9 +3334,8 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, 
		fl4.flowi4_iif = iif; /* for rt_fill_info */

		skb->dev	= dev;

		skb->mark	= mark;

		err = ip_route_input_rcu(skb, dst, src,

					 inet_dsfield_to_dscp(rtm->rtm_tos),

					 dev, &res) ? -EINVAL : 0;

		err = ip_route_input_rcu(skb, dst, src, dscp, dev,

					 &res) ? -EINVAL : 0;



		rt = skb_rtable(skb);

		if (err == 0 && rt->dst.error)