From b1ad41384866aafadf24c6b0f7e7701c86bdddc2 Mon Sep 17 00:00:00 2001 From: Guillaume Nault Date: Thu, 21 Apr 2022 01:21:37 +0200 Subject: 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 Reviewed-by: David Ahern Signed-off-by: David S. Miller --- net/ipv4/route.c | 37 +++++++++++++++++-------------------- 1 file changed, 17 insertions(+), 20 deletions(-) (limited to 'net/ipv4/route.c') 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); -- cgit v1.2.3