diff options
| author | Tom Herbert <tom@herbertland.com> | 2016-05-09 17:12:08 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-05-10 00:39:27 -0400 |
| commit | db2ec95d1ba419b766aae7b1d7c0271f3c9cd9f4 (patch) | |
| tree | ef6c5a38b5a944b9588b967f98715cc77b090654 | |
| parent | bfca2eba2adaa9501656f503559a971de6927fa8 (diff) | |
ip6_gre: Fix MTU setting
In ip6gre_tnl_link_config set t->tun_len and t->hlen correctly for the
configuration. For hard_header_len and mtu calculation include
IPv6 header and encapsulation overhead.
In ip6gre_tunnel_init_common set t->tun_len and t->hlen correctly for
the configuration. Revert to setting hard_header_len instead of
needed_headroom.
Tested:
./ip link add name tun8 type ip6gretap remote \
2401:db00:20:911a:face:0:27:0 local \
2401:db00:20:911a:face:0:25:0 ttl 225
Gives MTU of 1434. That is equal to 1500 - 40 - 14 - 4 - 8.
./ip link add name tun8 type ip6gretap remote \
2401:db00:20:911a:face:0:27:0 local \
2401:db00:20:911a:face:0:25:0 ttl 225 okey 123
Gives MTU of 1430. That is equal to 1500 - 40 - 14 - 4 - 8 - 4.
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv6/ip6_gre.c | 29 |
1 files changed, 13 insertions, 16 deletions
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index 47b671a46dc4..6d0aa94cf59a 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -700,7 +700,7 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu) struct net_device *dev = t->dev; struct __ip6_tnl_parm *p = &t->parms; struct flowi6 *fl6 = &t->fl.u.ip6; - int addend = sizeof(struct ipv6hdr) + 4; + int t_hlen; if (dev->type != ARPHRD_ETHER) { memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr)); @@ -727,16 +727,11 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu) else dev->flags &= ~IFF_POINTOPOINT; - /* Precalculate GRE options length */ - if (t->parms.o_flags&(GRE_CSUM|GRE_KEY|GRE_SEQ)) { - if (t->parms.o_flags&GRE_CSUM) - addend += 4; - if (t->parms.o_flags&GRE_KEY) - addend += 4; - if (t->parms.o_flags&GRE_SEQ) - addend += 4; - } - t->hlen = addend; + t->tun_hlen = gre_calc_hlen(t->parms.o_flags); + + t->hlen = t->tun_hlen; + + t_hlen = t->hlen + sizeof(struct ipv6hdr); if (p->flags & IP6_TNL_F_CAP_XMIT) { int strict = (ipv6_addr_type(&p->raddr) & @@ -750,10 +745,11 @@ static void ip6gre_tnl_link_config(struct ip6_tnl *t, int set_mtu) return; if (rt->dst.dev) { - dev->hard_header_len = rt->dst.dev->hard_header_len + addend; + dev->hard_header_len = rt->dst.dev->hard_header_len + + t_hlen; if (set_mtu) { - dev->mtu = rt->dst.dev->mtu - addend; + dev->mtu = rt->dst.dev->mtu - t_hlen; if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT)) dev->mtu -= 8; if (dev->type == ARPHRD_ETHER) @@ -1027,11 +1023,12 @@ static int ip6gre_tunnel_init_common(struct net_device *dev) tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags); - t_hlen = tunnel->hlen + sizeof(struct ipv6hdr); + tunnel->hlen = tunnel->tun_hlen; - dev->needed_headroom = LL_MAX_HEADER + t_hlen + 4; - dev->mtu = ETH_DATA_LEN - t_hlen - 4; + t_hlen = tunnel->hlen + sizeof(struct ipv6hdr); + dev->hard_header_len = LL_MAX_HEADER + t_hlen; + dev->mtu = ETH_DATA_LEN - t_hlen; if (!(tunnel->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT)) dev->mtu -= 8; |