From f7ff1fde9441b4fcc8ffb6e66e6e5a00d008937e Mon Sep 17 00:00:00 2001
From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Date: Thu, 31 May 2018 10:59:33 +0200
Subject: [PATCH] ip6_tunnel: remove magic mtu value 0xFFF8
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
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 da66aaac51cecb..00e138a44cbba2 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 2afce37a71776f..e9400ffa7875c7 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;
}
--
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