Re: [PATCH net] ipv4: fix route lookups when handling ICMP redirects and PMTU updates
From: David Ahern <dsahern@kernel.org>
Date: 2022-02-28 17:37:45
On 2/28/22 10:16 AM, Guillaume Nault wrote:
Fixes: d3a25c980fc2 ("ipv4: Fix nexthop exception hash computation.")That does not seem related to tos in the flow struct at all.
quoted hunk ↗ jump to hunk
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index f33ad1f383b6..d5d058de3664 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c@@ -499,6 +499,15 @@ void __ip_select_ident(struct net *net, struct iphdr *iph, int segs) } EXPORT_SYMBOL(__ip_select_ident); +static void ip_rt_fix_tos(struct flowi4 *fl4)
make this a static inline in include/net/flow.h and update flowi4_init_output and flowi4_update_output to use it. That should cover a few of the cases below leaving just ...
quoted hunk ↗ jump to hunk
+{ + __u8 tos = RT_FL_TOS(fl4); + + fl4->flowi4_tos = tos & IPTOS_RT_MASK; + fl4->flowi4_scope = tos & RTO_ONLINK ? + RT_SCOPE_LINK : RT_SCOPE_UNIVERSE; +} + static void __build_flow_key(const struct net *net, struct flowi4 *fl4, const struct sock *sk, const struct iphdr *iph,@@ -824,6 +833,7 @@ static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buf 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); }@@ -1048,6 +1058,7 @@ 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))@@ -1122,6 +1133,8 @@ 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);@@ -2603,7 +2616,6 @@ static struct rtable *__mkroute_output(const struct fib_result *res, struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, const struct sk_buff *skb) { - __u8 tos = RT_FL_TOS(fl4); struct fib_result res = { .type = RTN_UNSPEC, .fi = NULL,@@ -2613,9 +2625,7 @@ struct rtable *ip_route_output_key_hash(struct net *net, struct flowi4 *fl4, struct rtable *rth; fl4->flowi4_iif = LOOPBACK_IFINDEX; - fl4->flowi4_tos = tos & IPTOS_RT_MASK; - fl4->flowi4_scope = ((tos & RTO_ONLINK) ? - RT_SCOPE_LINK : RT_SCOPE_UNIVERSE); + ip_rt_fix_tos(fl4);
... this one to call the new helper.
rcu_read_lock(); rth = ip_route_output_key_hash_rcu(net, fl4, &res, skb);