Fredrik Markstrom
2017-May-11 13:46 UTC
[Bridge] [PATCH v2 1/2] net: Added mtu parameter to dev_forward_skb calls
From: Fredrik Markstr?m <fredrik.markstrom at gmail.com>
is_skb_forwardable() currently checks if the packet size is <= mtu of
the receiving interface. This is not consistent with most of the hardware
ethernet drivers that happily receives packets larger then MTU.
This patch adds a parameter to dev_forward_skb and is_skb_forwardable so
that the caller can override this packet size limit.
Signed-off-by: Fredrik Markstrom <fredrik.markstrom at gmail.com>
---
drivers/net/ipvlan/ipvlan_core.c | 7 ++++---
drivers/net/macvlan.c | 4 ++--
drivers/net/veth.c | 2 +-
include/linux/netdevice.h | 10 +++++-----
net/bridge/br_forward.c | 4 ++--
net/core/dev.c | 17 +++++++++++------
net/core/filter.c | 4 ++--
net/l2tp/l2tp_eth.c | 2 +-
8 files changed, 28 insertions(+), 22 deletions(-)
diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index 1f3295e274d0..dbbe48ade204 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -234,7 +234,8 @@ void ipvlan_process_multicast(struct work_struct *work)
nskb->pkt_type = pkt_type;
nskb->dev = ipvlan->dev;
if (tx_pkt)
- ret = dev_forward_skb(ipvlan->dev, nskb);
+ ret = dev_forward_skb(ipvlan->dev,
+ nskb, 0);
else
ret = netif_rx(nskb);
}
@@ -301,7 +302,7 @@ static int ipvlan_rcv_frame(struct ipvl_addr *addr, struct
sk_buff **pskb,
if (local) {
skb->pkt_type = PACKET_HOST;
- if (dev_forward_skb(ipvlan->dev, skb) == NET_RX_SUCCESS)
+ if (dev_forward_skb(ipvlan->dev, skb, 0) == NET_RX_SUCCESS)
success = true;
} else {
ret = RX_HANDLER_ANOTHER;
@@ -547,7 +548,7 @@ static int ipvlan_xmit_mode_l2(struct sk_buff *skb, struct
net_device *dev)
* the skb for the main-dev. At the RX side we just return
* RX_PASS for it to be processed further on the stack.
*/
- return dev_forward_skb(ipvlan->phy_dev, skb);
+ return dev_forward_skb(ipvlan->phy_dev, skb, 0);
} else if (is_multicast_ether_addr(eth->h_dest)) {
ipvlan_skb_crossing_ns(skb, NULL);
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 9261722960a7..4db2876c1e44 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -202,7 +202,7 @@ static int macvlan_broadcast_one(struct sk_buff *skb,
struct net_device *dev = vlan->dev;
if (local)
- return __dev_forward_skb(dev, skb);
+ return __dev_forward_skb(dev, skb, 0);
skb->dev = dev;
if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))
@@ -495,7 +495,7 @@ static int macvlan_queue_xmit(struct sk_buff *skb, struct
net_device *dev)
dest = macvlan_hash_lookup(port, eth->h_dest);
if (dest && dest->mode == MACVLAN_MODE_BRIDGE) {
/* send to lowerdev first for its network taps */
- dev_forward_skb(vlan->lowerdev, skb);
+ dev_forward_skb(vlan->lowerdev, skb, 0);
return NET_XMIT_SUCCESS;
}
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 8c39d6d690e5..561da3a63b8a 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -116,7 +116,7 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct
net_device *dev)
goto drop;
}
- if (likely(dev_forward_skb(rcv, skb) == NET_RX_SUCCESS)) {
+ if (likely(dev_forward_skb(rcv, skb, 0) == NET_RX_SUCCESS)) {
struct pcpu_vstats *stats = this_cpu_ptr(dev->vstats);
u64_stats_update_begin(&stats->syncp);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 97456b2539e4..f207b083ffec 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3282,16 +3282,16 @@ int dev_change_xdp_fd(struct net_device *dev, int fd,
u32 flags);
struct sk_buff *validate_xmit_skb_list(struct sk_buff *skb, struct net_device
*dev);
struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device
*dev,
struct netdev_queue *txq, int *ret);
-int __dev_forward_skb(struct net_device *dev, struct sk_buff *skb);
-int dev_forward_skb(struct net_device *dev, struct sk_buff *skb);
+int __dev_forward_skb(struct net_device *dev, struct sk_buff *skb, int mtu);
+int dev_forward_skb(struct net_device *dev, struct sk_buff *skb, int mtu);
bool is_skb_forwardable(const struct net_device *dev,
- const struct sk_buff *skb);
+ const struct sk_buff *skb, int mtu);
static __always_inline int ____dev_forward_skb(struct net_device *dev,
- struct sk_buff *skb)
+ struct sk_buff *skb, int mtu)
{
if (skb_orphan_frags(skb, GFP_ATOMIC) ||
- unlikely(!is_skb_forwardable(dev, skb))) {
+ unlikely(!is_skb_forwardable(dev, skb, mtu))) {
atomic_long_inc(&dev->rx_dropped);
kfree_skb(skb);
return NET_RX_DROP;
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 902af6ba481c..15ab57da5ef1 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -35,7 +35,7 @@ static inline int should_deliver(const struct net_bridge_port
*p,
int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff
*skb)
{
- if (!is_skb_forwardable(skb->dev, skb))
+ if (!is_skb_forwardable(skb->dev, skb, 0))
goto drop;
skb_push(skb, ETH_HLEN);
@@ -96,7 +96,7 @@ static void __br_forward(const struct net_bridge_port *to,
net = dev_net(indev);
} else {
if (unlikely(netpoll_tx_running(to->br->dev))) {
- if (!is_skb_forwardable(skb->dev, skb)) {
+ if (!is_skb_forwardable(skb->dev, skb, 0)) {
kfree_skb(skb);
} else {
skb_push(skb, ETH_HLEN);
diff --git a/net/core/dev.c b/net/core/dev.c
index 533a6d6f6092..f7c53d7c8e26 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1767,14 +1767,18 @@ static inline void net_timestamp_set(struct sk_buff
*skb)
__net_timestamp(SKB); \
} \
-bool is_skb_forwardable(const struct net_device *dev, const struct sk_buff
*skb)
+bool is_skb_forwardable(const struct net_device *dev,
+ const struct sk_buff *skb, int mtu)
{
unsigned int len;
if (!(dev->flags & IFF_UP))
return false;
- len = dev->mtu + dev->hard_header_len + VLAN_HLEN;
+ if (mtu == 0)
+ mtu = dev->mtu;
+
+ len = mtu + dev->hard_header_len + VLAN_HLEN;
if (skb->len <= len)
return true;
@@ -1788,9 +1792,9 @@ bool is_skb_forwardable(const struct net_device *dev,
const struct sk_buff *skb)
}
EXPORT_SYMBOL_GPL(is_skb_forwardable);
-int __dev_forward_skb(struct net_device *dev, struct sk_buff *skb)
+int __dev_forward_skb(struct net_device *dev, struct sk_buff *skb, int mtu)
{
- int ret = ____dev_forward_skb(dev, skb);
+ int ret = ____dev_forward_skb(dev, skb, mtu);
if (likely(!ret)) {
skb->protocol = eth_type_trans(skb, dev);
@@ -1806,6 +1810,7 @@ EXPORT_SYMBOL_GPL(__dev_forward_skb);
*
* @dev: destination network device
* @skb: buffer to forward
+ * @mtu: Maximum size to forward. If 0 dev->mtu is used.
*
* return values:
* NET_RX_SUCCESS (no congestion)
@@ -1819,9 +1824,9 @@ EXPORT_SYMBOL_GPL(__dev_forward_skb);
* we have to clear all information in the skb that could
* impact namespace isolation.
*/
-int dev_forward_skb(struct net_device *dev, struct sk_buff *skb)
+int dev_forward_skb(struct net_device *dev, struct sk_buff *skb, int mtu)
{
- return __dev_forward_skb(dev, skb) ?: netif_rx_internal(skb);
+ return __dev_forward_skb(dev, skb, mtu) ?: netif_rx_internal(skb);
}
EXPORT_SYMBOL_GPL(dev_forward_skb);
diff --git a/net/core/filter.c b/net/core/filter.c
index ebaeaf2e46e8..3f3eb26e7ea1 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1632,13 +1632,13 @@ static const struct bpf_func_proto bpf_csum_update_proto
= {
static inline int __bpf_rx_skb(struct net_device *dev, struct sk_buff *skb)
{
- return dev_forward_skb(dev, skb);
+ return dev_forward_skb(dev, skb, 0);
}
static inline int __bpf_rx_skb_no_mac(struct net_device *dev,
struct sk_buff *skb)
{
- int ret = ____dev_forward_skb(dev, skb);
+ int ret = ____dev_forward_skb(dev, skb, 0);
if (likely(!ret)) {
skb->dev = dev;
diff --git a/net/l2tp/l2tp_eth.c b/net/l2tp/l2tp_eth.c
index 6fd41d7afe1e..1258555b6578 100644
--- a/net/l2tp/l2tp_eth.c
+++ b/net/l2tp/l2tp_eth.c
@@ -164,7 +164,7 @@ static void l2tp_eth_dev_recv(struct l2tp_session *session,
struct sk_buff *skb,
skb_dst_drop(skb);
nf_reset(skb);
- if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
+ if (dev_forward_skb(dev, skb, 0) == NET_RX_SUCCESS) {
atomic_long_inc(&priv->rx_packets);
atomic_long_add(data_len, &priv->rx_bytes);
} else {
--
2.11.0
Stephen Hemminger
2017-May-11 16:01 UTC
[Bridge] [PATCH v2 1/2] net: Added mtu parameter to dev_forward_skb calls
On Thu, 11 May 2017 15:46:27 +0200 Fredrik Markstrom <fredrik.markstrom at gmail.com> wrote:> From: Fredrik Markstr?m <fredrik.markstrom at gmail.com> > > is_skb_forwardable() currently checks if the packet size is <= mtu of > the receiving interface. This is not consistent with most of the hardware > ethernet drivers that happily receives packets larger then MTU.Wrong. Hardware interfaces are free to drop any packet greater than MTU (actually MTU + VLAN). The actual limit is a function of the hardware. Some hardware can only limit by power of 2; some can only limit frames larger than 1500; some have no limiting at all. Any application that should: * not expect packets larger than MTU to be received * not send packets larger than MTU * check actual receive size. IP protocols will do truncation of padded packets