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Diffstat (limited to 'net/ipv6/tcp_ipv6.c')
-rw-r--r--net/ipv6/tcp_ipv6.c21
1 files changed, 18 insertions, 3 deletions
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 578ab6305c3f..0ce52d46e4f8 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -348,11 +348,20 @@ failure:
static void tcp_v6_mtu_reduced(struct sock *sk)
{
struct dst_entry *dst;
+ u32 mtu;
if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
return;
- dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
+ mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
+
+ /* Drop requests trying to increase our current mss.
+ * Check done in __ip6_rt_update_pmtu() is too late.
+ */
+ if (tcp_mtu_to_mss(sk, mtu) >= tcp_sk(sk)->mss_cache)
+ return;
+
+ dst = inet6_csk_update_pmtu(sk, mtu);
if (!dst)
return;
@@ -433,6 +442,8 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
}
if (type == ICMPV6_PKT_TOOBIG) {
+ u32 mtu = ntohl(info);
+
/* We are not interested in TCP_LISTEN and open_requests
* (SYN-ACKs send out by Linux are always <576bytes so
* they should go through unfragmented).
@@ -443,7 +454,11 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
if (!ip6_sk_accept_pmtu(sk))
goto out;
- tp->mtu_info = ntohl(info);
+ if (mtu < IPV6_MIN_MTU)
+ goto out;
+
+ WRITE_ONCE(tp->mtu_info, mtu);
+
if (!sock_owned_by_user(sk))
tcp_v6_mtu_reduced(sk);
else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
@@ -540,7 +555,7 @@ static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
opt = ireq->ipv6_opt;
if (!opt)
opt = rcu_dereference(np->opt);
- err = ip6_xmit(sk, skb, fl6, sk->sk_mark, opt,
+ err = ip6_xmit(sk, skb, fl6, skb->mark ? : sk->sk_mark, opt,
tclass, sk->sk_priority);
rcu_read_unlock();
err = net_xmit_eval(err);