]> bbs.cooldavid.org Git - net-next-2.6.git/blobdiff - net/core/dev.c
[NET]: Added GSO header verification
[net-next-2.6.git] / net / core / dev.c
index ab39fe17cb58bd0a49ce65376e279347a46fe248..4f2014994a847ce7066a7c8deee9d12befb9e354 100644 (file)
 #include <asm/current.h>
 #include <linux/audit.h>
 #include <linux/dmaengine.h>
+#include <linux/err.h>
 
 /*
  *     The list of packet types we will receive (as opposed to discard)
@@ -229,7 +230,7 @@ extern void netdev_unregister_sysfs(struct net_device *);
  *     For efficiency
  */
 
-int netdev_nit;
+static int netdev_nit;
 
 /*
  *     Add a protocol ID to the list. Now that the input handler is
@@ -1048,7 +1049,7 @@ static inline void net_timestamp(struct sk_buff *skb)
  *     taps currently in use.
  */
 
-void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
+static void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
 {
        struct packet_type *ptype;
 
@@ -1186,6 +1187,45 @@ out:
        return ret;
 }
 
+/**
+ *     skb_gso_segment - Perform segmentation on skb.
+ *     @skb: buffer to segment
+ *     @features: features for the output path (see dev->features)
+ *
+ *     This function segments the given skb and returns a list of segments.
+ *
+ *     It may return NULL if the skb requires no segmentation.  This is
+ *     only possible when GSO is used for verifying header integrity.
+ */
+struct sk_buff *skb_gso_segment(struct sk_buff *skb, int features)
+{
+       struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT);
+       struct packet_type *ptype;
+       int type = skb->protocol;
+
+       BUG_ON(skb_shinfo(skb)->frag_list);
+       BUG_ON(skb->ip_summed != CHECKSUM_HW);
+
+       skb->mac.raw = skb->data;
+       skb->mac_len = skb->nh.raw - skb->data;
+       __skb_pull(skb, skb->mac_len);
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(ptype, &ptype_base[ntohs(type) & 15], list) {
+               if (ptype->type == type && !ptype->dev && ptype->gso_segment) {
+                       segs = ptype->gso_segment(skb, features);
+                       break;
+               }
+       }
+       rcu_read_unlock();
+
+       __skb_push(skb, skb->data - skb->mac.raw);
+
+       return segs;
+}
+
+EXPORT_SYMBOL(skb_gso_segment);
+
 /* Take action when hardware reception checksum errors are detected. */
 #ifdef CONFIG_BUG
 void netdev_rx_csum_fault(struct net_device *dev)
@@ -1222,6 +1262,99 @@ static inline int illegal_highdma(struct net_device *dev, struct sk_buff *skb)
 #define illegal_highdma(dev, skb)      (0)
 #endif
 
+struct dev_gso_cb {
+       void (*destructor)(struct sk_buff *skb);
+};
+
+#define DEV_GSO_CB(skb) ((struct dev_gso_cb *)(skb)->cb)
+
+static void dev_gso_skb_destructor(struct sk_buff *skb)
+{
+       struct dev_gso_cb *cb;
+
+       do {
+               struct sk_buff *nskb = skb->next;
+
+               skb->next = nskb->next;
+               nskb->next = NULL;
+               kfree_skb(nskb);
+       } while (skb->next);
+
+       cb = DEV_GSO_CB(skb);
+       if (cb->destructor)
+               cb->destructor(skb);
+}
+
+/**
+ *     dev_gso_segment - Perform emulated hardware segmentation on skb.
+ *     @skb: buffer to segment
+ *
+ *     This function segments the given skb and stores the list of segments
+ *     in skb->next.
+ */
+static int dev_gso_segment(struct sk_buff *skb)
+{
+       struct net_device *dev = skb->dev;
+       struct sk_buff *segs;
+       int features = dev->features & ~(illegal_highdma(dev, skb) ?
+                                        NETIF_F_SG : 0);
+
+       segs = skb_gso_segment(skb, features);
+
+       /* Verifying header integrity only. */
+       if (!segs)
+               return 0;
+
+       if (unlikely(IS_ERR(segs)))
+               return PTR_ERR(segs);
+
+       skb->next = segs;
+       DEV_GSO_CB(skb)->destructor = skb->destructor;
+       skb->destructor = dev_gso_skb_destructor;
+
+       return 0;
+}
+
+int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+       if (likely(!skb->next)) {
+               if (netdev_nit)
+                       dev_queue_xmit_nit(skb, dev);
+
+               if (netif_needs_gso(dev, skb)) {
+                       if (unlikely(dev_gso_segment(skb)))
+                               goto out_kfree_skb;
+                       if (skb->next)
+                               goto gso;
+               }
+
+               return dev->hard_start_xmit(skb, dev);
+       }
+
+gso:
+       do {
+               struct sk_buff *nskb = skb->next;
+               int rc;
+
+               skb->next = nskb->next;
+               nskb->next = NULL;
+               rc = dev->hard_start_xmit(nskb, dev);
+               if (unlikely(rc)) {
+                       nskb->next = skb->next;
+                       skb->next = nskb;
+                       return rc;
+               }
+               if (unlikely(netif_queue_stopped(dev) && skb->next))
+                       return NETDEV_TX_BUSY;
+       } while (skb->next);
+       
+       skb->destructor = DEV_GSO_CB(skb)->destructor;
+
+out_kfree_skb:
+       kfree_skb(skb);
+       return 0;
+}
+
 #define HARD_TX_LOCK(dev, cpu) {                       \
        if ((dev->features & NETIF_F_LLTX) == 0) {      \
                netif_tx_lock(dev);                     \
@@ -1266,6 +1399,10 @@ int dev_queue_xmit(struct sk_buff *skb)
        struct Qdisc *q;
        int rc = -ENOMEM;
 
+       /* GSO will handle the following emulations directly. */
+       if (netif_needs_gso(dev, skb))
+               goto gso;
+
        if (skb_shinfo(skb)->frag_list &&
            !(dev->features & NETIF_F_FRAGLIST) &&
            __skb_linearize(skb))
@@ -1290,12 +1427,13 @@ int dev_queue_xmit(struct sk_buff *skb)
                if (skb_checksum_help(skb, 0))
                        goto out_kfree_skb;
 
+gso:
        spin_lock_prefetch(&dev->queue_lock);
 
        /* Disable soft irqs for various locks below. Also 
         * stops preemption for RCU. 
         */
-       local_bh_disable(); 
+       rcu_read_lock_bh(); 
 
        /* Updates of qdisc are serialized by queue_lock. 
         * The struct Qdisc which is pointed to by qdisc is now a 
@@ -1346,11 +1484,8 @@ int dev_queue_xmit(struct sk_buff *skb)
                        HARD_TX_LOCK(dev, cpu);
 
                        if (!netif_queue_stopped(dev)) {
-                               if (netdev_nit)
-                                       dev_queue_xmit_nit(skb, dev);
-
                                rc = 0;
-                               if (!dev->hard_start_xmit(skb, dev)) {
+                               if (!dev_hard_start_xmit(skb, dev)) {
                                        HARD_TX_UNLOCK(dev);
                                        goto out;
                                }
@@ -1369,13 +1504,13 @@ int dev_queue_xmit(struct sk_buff *skb)
        }
 
        rc = -ENETDOWN;
-       local_bh_enable();
+       rcu_read_unlock_bh();
 
 out_kfree_skb:
        kfree_skb(skb);
        return rc;
 out:
-       local_bh_enable();
+       rcu_read_unlock_bh();
        return rc;
 }
 
@@ -2980,7 +3115,7 @@ static void netdev_wait_allrefs(struct net_device *dev)
 static DEFINE_MUTEX(net_todo_run_mutex);
 void netdev_run_todo(void)
 {
-       struct list_head list = LIST_HEAD_INIT(list);
+       struct list_head list;
 
        /* Need to guard against multiple cpu's getting out of order. */
        mutex_lock(&net_todo_run_mutex);
@@ -2995,9 +3130,9 @@ void netdev_run_todo(void)
 
        /* Snapshot list, allow later requests */
        spin_lock(&net_todo_list_lock);
-       list_splice_init(&net_todo_list, &list);
+       list_replace_init(&net_todo_list, &list);
        spin_unlock(&net_todo_list_lock);
-               
+
        while (!list_empty(&list)) {
                struct net_device *dev
                        = list_entry(list.next, struct net_device, todo_list);
@@ -3301,8 +3436,8 @@ static void net_dma_rebalance(void)
 /**
  * netdev_dma_event - event callback for the net_dma_client
  * @client: should always be net_dma_client
- * @chan:
- * @event:
+ * @chan: DMA channel for the event
+ * @event: event type
  */
 static void netdev_dma_event(struct dma_client *client, struct dma_chan *chan,
        enum dma_event event)