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From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
To: davem@davemloft.net, petrm@mellanox.com, idosch@mellanox.com
Cc: netdev@vger.kernel.org, Nicolas Dichtel <nicolas.dichtel@6wind.com>
Subject: [PATCH net 2/2] ip6_tunnel: remove magic mtu value 0xFFF8
Date: Wed, 30 May 2018 10:28:43 +0200	[thread overview]
Message-ID: <20180530082843.6076-3-nicolas.dichtel@6wind.com> (raw)
In-Reply-To: <20180530082843.6076-1-nicolas.dichtel@6wind.com>

I don't know where this value comes from (probably a copy and paste and
paste and paste ...).
Let's use standard values which are a bit greater.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/davem/netdev-vger-cvs.git/commit/?id=e5afd356a411a
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
---
 net/ipv6/ip6_tunnel.c | 11 ++++++++---
 net/ipv6/sit.c        |  5 +++--
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index da66aaac51ce..00e138a44cbb 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1692,8 +1692,13 @@ int ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
 		if (new_mtu < ETH_MIN_MTU)
 			return -EINVAL;
 	}
-	if (new_mtu > 0xFFF8 - dev->hard_header_len)
-		return -EINVAL;
+	if (tnl->parms.proto == IPPROTO_IPV6 || tnl->parms.proto == 0) {
+		if (new_mtu > IP6_MAX_MTU - dev->hard_header_len)
+			return -EINVAL;
+	} else {
+		if (new_mtu > IP_MAX_MTU - dev->hard_header_len)
+			return -EINVAL;
+	}
 	dev->mtu = new_mtu;
 	return 0;
 }
@@ -1841,7 +1846,7 @@ ip6_tnl_dev_init_gen(struct net_device *dev)
 	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
 		dev->mtu -= 8;
 	dev->min_mtu = ETH_MIN_MTU;
-	dev->max_mtu = 0xFFF8 - dev->hard_header_len;
+	dev->max_mtu = IP6_MAX_MTU - dev->hard_header_len;
 
 	return 0;
 
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 2afce37a7177..e9400ffa7875 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1371,7 +1371,7 @@ static void ipip6_tunnel_setup(struct net_device *dev)
 	dev->hard_header_len	= LL_MAX_HEADER + t_hlen;
 	dev->mtu		= ETH_DATA_LEN - t_hlen;
 	dev->min_mtu		= IPV6_MIN_MTU;
-	dev->max_mtu		= 0xFFF8 - t_hlen;
+	dev->max_mtu		= IP6_MAX_MTU - t_hlen;
 	dev->flags		= IFF_NOARP;
 	netif_keep_dst(dev);
 	dev->addr_len		= 4;
@@ -1583,7 +1583,8 @@ static int ipip6_newlink(struct net *src_net, struct net_device *dev,
 	if (tb[IFLA_MTU]) {
 		u32 mtu = nla_get_u32(tb[IFLA_MTU]);
 
-		if (mtu >= IPV6_MIN_MTU && mtu <= 0xFFF8 - dev->hard_header_len)
+		if (mtu >= IPV6_MIN_MTU &&
+		    mtu <= IP6_MAX_MTU - dev->hard_header_len)
 			dev->mtu = mtu;
 	}
 
-- 
2.15.1

      parent reply	other threads:[~2018-05-30  8:35 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-30  8:28 [PATCH net 0/2] ip[6] tunnels: fix mtu calculations Nicolas Dichtel
2018-05-30  8:28 ` [PATCH net 1/2] ip_tunnel: restore binding to ifaces with a large mtu Nicolas Dichtel
2018-05-30 20:29   ` Ido Schimmel
2018-05-31  8:52     ` Nicolas Dichtel
2018-05-31  8:59     ` [PATCH net v2 0/2] ip[6] tunnels: fix mtu calculations Nicolas Dichtel
2018-05-31  8:59       ` [PATCH net v2 1/2] ip_tunnel: restore binding to ifaces with a large mtu Nicolas Dichtel
2018-05-31  8:59       ` [PATCH net v2 2/2] ip6_tunnel: remove magic mtu value 0xFFF8 Nicolas Dichtel
2018-06-01 17:57       ` [PATCH net v2 0/2] ip[6] tunnels: fix mtu calculations David Miller
2018-06-04  7:56         ` Nicolas Dichtel
2018-05-30  8:28 ` Nicolas Dichtel [this message]

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