ipv4: Convert ip_route_input() to dscp_t.

Pass a dscp_t variable to ip_route_input(), instead of a plain u8, to
prevent accidental setting of ECN bits in ->flowi4_tos.

Callers of ip_route_input() to consider are:

  * input_action_end_dx4_finish() and input_action_end_dt4() in
    net/ipv6/seg6_local.c. These functions set the tos parameter to 0,
    which is already a valid dscp_t value, so they don't need to be
    adjusted for the new prototype.

  * icmp_route_lookup(), which already has a dscp_t variable to pass as
    parameter. We just need to remove the inet_dscp_to_dsfield()
    conversion.

  * br_nf_pre_routing_finish(), ip_options_rcv_srr() and ip4ip6_err(),
    which get the DSCP directly from IPv4 headers. Define a helper to
    read the .tos field of struct iphdr as dscp_t, so that these
    function don't have to do the conversion manually.

While there, declare *iph as const in br_nf_pre_routing_finish(),
declare its local variables in reverse-christmas-tree order and move
the "err = ip_route_input()" assignment out of the conditional to avoid
checkpatch warning.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/e9d40781d64d3d69f4c79ac8a008b8d67a033e8d.1727807926.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/net/ip.h b/include/net/ip.h
index d92d3bc3ec0e25731ee3917ef9db5f0ade56952b..bab084df15677543b7400bb2832c0e83988884cb 100644 (file)
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -424,6 +424,11 @@ int ip_decrease_ttl(struct iphdr *iph)
        return --iph->ttl;
 }
 
+static inline dscp_t ip4h_dscp(const struct iphdr *ip4h)
+{
+       return inet_dsfield_to_dscp(ip4h->tos);
+}
+
 static inline int ip_mtu_locked(const struct dst_entry *dst)
 {
        const struct rtable *rt = dst_rtable(dst);

diff --git a/include/net/route.h b/include/net/route.h
index 1789f1e6640b466f7eaa9efb7765c53b3748df66..03dd28cf4bc48c015d647b5c1c509b9f85cccdd1 100644 (file)
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -208,12 +208,13 @@ int ip_route_use_hint(struct sk_buff *skb, __be32 dst, __be32 src,
                      const struct sk_buff *hint);
 
 static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,
-                                u8 tos, struct net_device *devin)
+                                dscp_t dscp, struct net_device *devin)
 {
        int err;
 
        rcu_read_lock();
-       err = ip_route_input_noref(skb, dst, src, tos, devin);
+       err = ip_route_input_noref(skb, dst, src, inet_dscp_to_dsfield(dscp),
+                                  devin);
        if (!err) {
                skb_dst_force(skb);
                if (!skb_dst(skb))

diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
index 0e8bc0ea6175066481c38963b22c2375c8a15d23..c6bab2b5e8348809777cff4a9ab07c947eac71c9 100644 (file)
--- a/net/bridge/br_netfilter_hooks.c
+++ b/net/bridge/br_netfilter_hooks.c
@@ -369,9 +369,9 @@ br_nf_ipv4_daddr_was_changed(const struct sk_buff *skb,
  */
 static int br_nf_pre_routing_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-       struct net_device *dev = skb->dev, *br_indev;
-       struct iphdr *iph = ip_hdr(skb);
        struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
+       struct net_device *dev = skb->dev, *br_indev;
+       const struct iphdr *iph = ip_hdr(skb);
        struct rtable *rt;
        int err;
 
@@ -389,7 +389,9 @@ static int br_nf_pre_routing_finish(struct net *net, struct sock *sk, struct sk_
        }
        nf_bridge->in_prerouting = 0;
        if (br_nf_ipv4_daddr_was_changed(skb, nf_bridge)) {
-               if ((err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos, dev))) {
+               err = ip_route_input(skb, iph->daddr, iph->saddr,
+                                    ip4h_dscp(iph), dev);
+               if (err) {
                        struct in_device *in_dev = __in_dev_get_rcu(dev);
 
                        /* If err equals -EHOSTUNREACH the error is due to a

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 7d7b25ed8d21b160253a17005e48ad726057c1de..23664434922edef7a553cb4d4c93a17524b28eff 100644 (file)
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -545,7 +545,7 @@ static struct rtable *icmp_route_lookup(struct net *net, struct flowi4 *fl4,
                orefdst = skb_in->_skb_refdst; /* save old refdst */
                skb_dst_set(skb_in, NULL);
                err = ip_route_input(skb_in, fl4_dec.daddr, fl4_dec.saddr,
-                                    inet_dscp_to_dsfield(dscp), rt2->dst.dev);
+                                    dscp, rt2->dst.dev);
 
                dst_release(&rt2->dst);
                rt2 = skb_rtable(skb_in);

diff --git a/net/ipv4/ip_options.c b/net/ipv4/ip_options.c
index 68aedb8877b9f4e2c6bc9e7afe2f90afb96a76ec..81e86e5defee6b81b60573fe6b5f3ef8e2dfdd5b 100644 (file)
--- a/net/ipv4/ip_options.c
+++ b/net/ipv4/ip_options.c
@@ -617,7 +617,8 @@ int ip_options_rcv_srr(struct sk_buff *skb, struct net_device *dev)
 
                orefdst = skb->_skb_refdst;
                skb_dst_set(skb, NULL);
-               err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, dev);
+               err = ip_route_input(skb, nexthop, iph->saddr, ip4h_dscp(iph),
+                                    dev);
                rt2 = skb_rtable(skb);
                if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
                        skb_dst_drop(skb);

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index b60e13c42bcacd56c89db773dcd90480b4d892d8..48fd53b9897265338086136e96ea8e8c6ec3cac8 100644 (file)
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -630,8 +630,8 @@ ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                }
                skb_dst_set(skb2, &rt->dst);
        } else {
-               if (ip_route_input(skb2, eiph->daddr, eiph->saddr, eiph->tos,
-                                  skb2->dev) ||
+               if (ip_route_input(skb2, eiph->daddr, eiph->saddr,
+                                  ip4h_dscp(eiph), skb2->dev) ||
                    skb_dst(skb2)->dev->type != ARPHRD_TUNNEL6)
                        goto out;
        }