From 55e5bfb53cff286c1c1ff49f51325dc15c7fea63 Mon Sep 17 00:00:00 2001 From: David Wragg Date: Wed, 10 Feb 2016 00:05:57 +0000 Subject: geneve: Relax MTU constraints Allow the MTU of geneve devices to be set to large values, in order to exploit underlying networks with larger frame sizes. GENEVE does not have a fixed encapsulation overhead (an openvswitch rule can add variable length options), so there is no relevant maximum MTU to enforce. A maximum of IP_MAX_MTU is used instead. Encapsulated packets that are too big for the underlying network will get dropped on the floor. Signed-off-by: David Wragg Signed-off-by: David S. Miller --- drivers/net/geneve.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'drivers/net/geneve.c') diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 0b14ac3b8d11..d2031ce8baea 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -1039,6 +1039,17 @@ static netdev_tx_t geneve_xmit(struct sk_buff *skb, struct net_device *dev) return geneve_xmit_skb(skb, dev, info); } +static int geneve_change_mtu(struct net_device *dev, int new_mtu) +{ + /* GENEVE overhead is not fixed, so we can't enforce a more + * precise max MTU. + */ + if (new_mtu < 68 || new_mtu > IP_MAX_MTU) + return -EINVAL; + dev->mtu = new_mtu; + return 0; +} + static int geneve_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb) { struct ip_tunnel_info *info = skb_tunnel_info(skb); @@ -1083,7 +1094,7 @@ static const struct net_device_ops geneve_netdev_ops = { .ndo_stop = geneve_stop, .ndo_start_xmit = geneve_xmit, .ndo_get_stats64 = ip_tunnel_get_stats64, - .ndo_change_mtu = eth_change_mtu, + .ndo_change_mtu = geneve_change_mtu, .ndo_validate_addr = eth_validate_addr, .ndo_set_mac_address = eth_mac_addr, .ndo_fill_metadata_dst = geneve_fill_metadata_dst, -- cgit From 7e059158d57b79159eaf1f504825d19866ef2c42 Mon Sep 17 00:00:00 2001 From: David Wragg Date: Wed, 10 Feb 2016 00:05:58 +0000 Subject: vxlan, gre, geneve: Set a large MTU on ovs-created tunnel devices Prior to 4.3, openvswitch tunnel vports (vxlan, gre and geneve) could transmit vxlan packets of any size, constrained only by the ability to send out the resulting packets. 4.3 introduced netdevs corresponding to tunnel vports. These netdevs have an MTU, which limits the size of a packet that can be successfully encapsulated. The default MTU values are low (1500 or less), which is awkwardly small in the context of physical networks supporting jumbo frames, and leads to a conspicuous change in behaviour for userspace. Instead, set the MTU on openvswitch-created netdevs to be the relevant maximum (i.e. the maximum IP packet size minus any relevant overhead), effectively restoring the behaviour prior to 4.3. Signed-off-by: David Wragg Signed-off-by: David S. Miller --- drivers/net/geneve.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) (limited to 'drivers/net/geneve.c') diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index d2031ce8baea..028e3873c310 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -1453,11 +1453,21 @@ struct net_device *geneve_dev_create_fb(struct net *net, const char *name, err = geneve_configure(net, dev, &geneve_remote_unspec, 0, 0, 0, htons(dst_port), true, 0); - if (err) { - free_netdev(dev); - return ERR_PTR(err); - } + if (err) + goto err; + + /* openvswitch users expect packet sizes to be unrestricted, + * so set the largest MTU we can. + */ + err = geneve_change_mtu(dev, IP_MAX_MTU); + if (err) + goto err; + return dev; + + err: + free_netdev(dev); + return ERR_PTR(err); } EXPORT_SYMBOL_GPL(geneve_dev_create_fb); -- cgit From aeee0e66c6b46cee311be22cb82735763eceb7c3 Mon Sep 17 00:00:00 2001 From: David Wragg Date: Thu, 18 Feb 2016 17:43:29 +0000 Subject: geneve: Refine MTU limit Calculate the maximum MTU taking into account the size of headers involved in GENEVE encapsulation, as for other tunnel types. Changes in v3: - Correct comment style Changes in v2: - Conform more closely to ip_tunnel_change_mtu - Exclude GENEVE options from max MTU calculation Signed-off-by: David Wragg Acked-by: Jesse Gross Signed-off-by: David S. Miller --- drivers/net/geneve.c | 27 ++++++++++++++++++++++----- 1 file changed, 22 insertions(+), 5 deletions(-) (limited to 'drivers/net/geneve.c') diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 028e3873c310..70975700f91d 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -1039,17 +1039,34 @@ static netdev_tx_t geneve_xmit(struct sk_buff *skb, struct net_device *dev) return geneve_xmit_skb(skb, dev, info); } -static int geneve_change_mtu(struct net_device *dev, int new_mtu) +static int __geneve_change_mtu(struct net_device *dev, int new_mtu, bool strict) { - /* GENEVE overhead is not fixed, so we can't enforce a more - * precise max MTU. + /* The max_mtu calculation does not take account of GENEVE + * options, to avoid excluding potentially valid + * configurations. */ - if (new_mtu < 68 || new_mtu > IP_MAX_MTU) + int max_mtu = IP_MAX_MTU - GENEVE_BASE_HLEN - sizeof(struct iphdr) + - dev->hard_header_len; + + if (new_mtu < 68) return -EINVAL; + + if (new_mtu > max_mtu) { + if (strict) + return -EINVAL; + + new_mtu = max_mtu; + } + dev->mtu = new_mtu; return 0; } +static int geneve_change_mtu(struct net_device *dev, int new_mtu) +{ + return __geneve_change_mtu(dev, new_mtu, true); +} + static int geneve_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb) { struct ip_tunnel_info *info = skb_tunnel_info(skb); @@ -1459,7 +1476,7 @@ struct net_device *geneve_dev_create_fb(struct net *net, const char *name, /* openvswitch users expect packet sizes to be unrestricted, * so set the largest MTU we can. */ - err = geneve_change_mtu(dev, IP_MAX_MTU); + err = __geneve_change_mtu(dev, IP_MAX_MTU, false); if (err) goto err; -- cgit From fc41cdb322a2a513efd60f81133efecd69d4f336 Mon Sep 17 00:00:00 2001 From: Jiri Benc Date: Wed, 17 Feb 2016 15:31:35 +0100 Subject: geneve: clear IFF_TX_SKB_SHARING ether_setup sets IFF_TX_SKB_SHARING but this is not supported by geneve as it modifies the skb on xmit. Signed-off-by: Jiri Benc Signed-off-by: David S. Miller --- drivers/net/geneve.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/net/geneve.c') diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 70975700f91d..4a9cc038c4b0 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -1178,6 +1178,7 @@ static void geneve_setup(struct net_device *dev) dev->hw_features |= NETIF_F_GSO_SOFTWARE; netif_keep_dst(dev); + dev->priv_flags &= ~IFF_TX_SKB_SHARING; dev->priv_flags |= IFF_LIVE_ADDR_CHANGE | IFF_NO_QUEUE; eth_hw_addr_random(dev); } -- cgit From c868ee7063bdb53f3ef9eac7bcec84960980b471 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Wed, 17 Feb 2016 19:30:01 +0100 Subject: lwt: fix rx checksum setting for lwt devices tunneling over ipv6 the commit 35e2d1152b22 ("tunnels: Allow IPv6 UDP checksums to be correctly controlled.") changed the default xmit checksum setting for lwt vxlan/geneve ipv6 tunnels, so that now the checksum is not set into external UDP header. This commit changes the rx checksum setting for both lwt vxlan/geneve devices created by openvswitch accordingly, so that lwt over ipv6 tunnel pairs are again able to communicate with default values. Signed-off-by: Paolo Abeni Acked-by: Jiri Benc Acked-by: Jesse Gross Signed-off-by: David S. Miller --- drivers/net/geneve.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/net/geneve.c') diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 4a9cc038c4b0..0bf7edd99573 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -1470,7 +1470,8 @@ struct net_device *geneve_dev_create_fb(struct net *net, const char *name, return dev; err = geneve_configure(net, dev, &geneve_remote_unspec, - 0, 0, 0, htons(dst_port), true, 0); + 0, 0, 0, htons(dst_port), true, + GENEVE_F_UDP_ZERO_CSUM6_RX); if (err) goto err; -- cgit