[PATCH 1/3] macvlan: Reflect macvlan packets meant for other macvlan devices

Arnd Bergmann
2009-11-17T22:41:29Z

From: Eric Biederman <ebiederm@xmission.com>

Switch ports do not send packets back out the same port they came
in on. This causes problems when using a macvlan device inside
of a network namespace as it becomes impossible to talk to
other macvlan devices.

Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/net/macvlan.c | 91 ++++++++++++++++++++++++++++++++++++-------------
1 files changed, 67 insertions(+), 24 deletions(-)

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 3aabfd9..406b8b5 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -29,6 +29,7 @@
#include <linux/if_link.h>
#include <linux/if_macvlan.h>
#include <net/rtnetlink.h>
+#include <net/xfrm.h>

#define MACVLAN_HASH_SIZE (1 << BITS_PER_BYTE)

@@ -102,7 +103,8 @@ static int macvlan_addr_busy(const struct macvlan_port *port,
}

static void macvlan_broadcast(struct sk_buff *skb,
- const struct macvlan_port *port)
+ const struct macvlan_port *port,
+ struct net_device *src)
{
const struct ethhdr *eth = eth_hdr(skb);
const struct macvlan_dev *vlan;
@@ -118,6 +120,9 @@ static void macvlan_broadcast(struct sk_buff *skb,
hlist_for_each_entry_rcu(vlan, n, &port->vlan_hash[i], hlist) {
dev = vlan->dev;

+ if (dev == src)
+ continue;
+
nskb = skb_clone(skb, GFP_ATOMIC);
if (nskb == NULL) {
dev->stats.rx_errors++;
@@ -140,20 +145,45 @@ static void macvlan_broadcast(struct sk_buff *skb,
}
}

+static int macvlan_unicast(struct sk_buff *skb, const struct macvlan_dev *dest)
+{
+ struct net_device *dev = dest->dev;
+
+ if (unlikely(!dev->flags & IFF_UP)) {
+ kfree_skb(skb);
+ return NET_XMIT_DROP;
+ }
+
+ skb = skb_share_check(skb, GFP_ATOMIC);
+ if (!skb) {
+ dev->stats.rx_errors++;
+ dev->stats.rx_dropped++;
+ return NET_XMIT_DROP;
+ }
+
+ dev->stats.rx_bytes += skb->len + ETH_HLEN;
+ dev->stats.rx_packets++;
+
+ skb->dev = dev;
+ skb->pkt_type = PACKET_HOST;
+ netif_rx(skb);
+ return NET_XMIT_SUCCESS;
+}
+
+
/* called under rcu_read_lock() from netif_receive_skb */
static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
{
const struct ethhdr *eth = eth_hdr(skb);
const struct macvlan_port *port;
const struct macvlan_dev *vlan;
- struct net_device *dev;

port = rcu_dereference(skb->dev->macvlan_port);
if (port == NULL)
return skb;

if (is_multicast_ether_addr(eth->h_dest)) {
- macvlan_broadcast(skb, port);
+ macvlan_broadcast(skb, port, NULL);
return skb;
}

@@ -161,27 +191,43 @@ static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
if (vlan == NULL)
return skb;

- dev = vlan->dev;
- if (unlikely(!(dev->flags & IFF_UP))) {
- kfree_skb(skb);
- return NULL;
- }
+ macvlan_unicast(skb, vlan);
+ return NULL;
+}

- skb = skb_share_check(skb, GFP_ATOMIC);
- if (skb == NULL) {
- dev->stats.rx_errors++;
- dev->stats.rx_dropped++;
- return NULL;
- }
+static int macvlan_xmit_world(struct sk_buff *skb, struct net_device *dev)
+{
+ const struct macvlan_dev *vlan = netdev_priv(dev);
+ __skb_push(skb, skb->data - skb_mac_header(skb));
+ skb->dev = vlan->lowerdev;
+ return dev_queue_xmit(skb);
+}

- dev->stats.rx_bytes += skb->len + ETH_HLEN;
- dev->stats.rx_packets++;
+static int macvlan_queue_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ const struct macvlan_dev *vlan = netdev_priv(dev);
+ const struct macvlan_port *port = vlan->port;
+ const struct macvlan_dev *dest;
+ const struct ethhdr *eth;

- skb->dev = dev;
- skb->pkt_type = PACKET_HOST;
+ skb->protocol = eth_type_trans(skb, dev);
+ eth = eth_hdr(skb);

- netif_rx(skb);
- return NULL;
+ skb_dst_drop(skb);
+ skb->mark = 0;
+ secpath_reset(skb);
+ nf_reset(skb);
+
+ if (is_multicast_ether_addr(eth->h_dest)) {
+ macvlan_broadcast(skb, port, dev);
+ return macvlan_xmit_world(skb, dev);
+ }
+
+ dest = macvlan_hash_lookup(port, eth->h_dest);
+ if (dest)
+ return macvlan_unicast(skb, dest);
+
+ return macvlan_xmit_world(skb, dev);
}

static netdev_tx_t macvlan_start_xmit(struct sk_buff *skb,
@@ -189,13 +235,10 @@ static netdev_tx_t macvlan_start_xmit(struct sk_buff *skb,
{
int i = skb_get_queue_mapping(skb);
struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
- const struct macvlan_dev *vlan = netdev_priv(dev);
unsigned int len = skb->len;
int ret;

- skb->dev = vlan->lowerdev;
- ret = dev_queue_xmit(skb);
-
+ ret = macvlan_queue_xmit(skb, dev);
if (likely(ret == NET_XMIT_SUCCESS)) {
txq->tx_packets++;
txq->tx_bytes += len;
--
1.6.3.3