Staging: batman-adv: Directly prepare icmp packets in socket buffer

It is unnecessary to generate an icmp packet in an extra memory region
and than copying it to a new allocated skb.

This also resolved the problem that we do inform the user that we
couldn't send the packet because we couldn't allocate the socket buffer.
Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/batman-adv/icmp_socket.c

@@ -154,7 +154,8 @@ static ssize_t bat_socket_write(struct file *file, const char __user *buff,
 {
 	struct socket_client *socket_client = file->private_data;
 	struct bat_priv *bat_priv = socket_client->bat_priv;
-	struct icmp_packet_rr icmp_packet;
+	struct sk_buff *skb;
+	struct icmp_packet_rr *icmp_packet;
 	struct orig_node *orig_node;
 	struct batman_if *batman_if;
 	size_t packet_len = sizeof(struct icmp_packet);
@@ -174,40 +175,53 @@ static ssize_t bat_socket_write(struct file *file, const char __user *buff,
 	if (len >= sizeof(struct icmp_packet_rr))
 		packet_len = sizeof(struct icmp_packet_rr);
 
-	if (!access_ok(VERIFY_READ, buff, packet_len))
-		return -EFAULT;
+	skb = dev_alloc_skb(packet_len + sizeof(struct ethhdr));
+	if (!skb)
+		return -ENOMEM;
 
-	if (__copy_from_user(&icmp_packet, buff, packet_len))
-		return -EFAULT;
+	skb_reserve(skb, sizeof(struct ethhdr));
+	icmp_packet = (struct icmp_packet_rr *)skb_put(skb, packet_len);
 
-	if (icmp_packet.packet_type != BAT_ICMP) {
+	if (!access_ok(VERIFY_READ, buff, packet_len)) {
+		len = -EFAULT;
+		goto free_skb;
+	}
+
+	if (__copy_from_user(icmp_packet, buff, packet_len)) {
+		len = -EFAULT;
+		goto free_skb;
+	}
+
+	if (icmp_packet->packet_type != BAT_ICMP) {
 		bat_dbg(DBG_BATMAN, bat_priv,
 			"Error - can't send packet from char device: "
 			"got bogus packet type (expected: BAT_ICMP)\n");
-		return -EINVAL;
+		len = -EINVAL;
+		goto free_skb;
 	}
 
-	if (icmp_packet.msg_type != ECHO_REQUEST) {
+	if (icmp_packet->msg_type != ECHO_REQUEST) {
 		bat_dbg(DBG_BATMAN, bat_priv,
 			"Error - can't send packet from char device: "
 			"got bogus message type (expected: ECHO_REQUEST)\n");
-		return -EINVAL;
+		len = -EINVAL;
+		goto free_skb;
 	}
 
-	icmp_packet.uid = socket_client->index;
+	icmp_packet->uid = socket_client->index;
 
-	if (icmp_packet.version != COMPAT_VERSION) {
-		icmp_packet.msg_type = PARAMETER_PROBLEM;
-		icmp_packet.ttl = COMPAT_VERSION;
-		bat_socket_add_packet(socket_client, &icmp_packet, packet_len);
-		goto out;
+	if (icmp_packet->version != COMPAT_VERSION) {
+		icmp_packet->msg_type = PARAMETER_PROBLEM;
+		icmp_packet->ttl = COMPAT_VERSION;
+		bat_socket_add_packet(socket_client, icmp_packet, packet_len);
+		goto free_skb;
 	}
 
 	if (atomic_read(&module_state) != MODULE_ACTIVE)
 		goto dst_unreach;
 
 	spin_lock_irqsave(&orig_hash_lock, flags);
-	orig_node = ((struct orig_node *)hash_find(orig_hash, icmp_packet.dst));
+	orig_node = (struct orig_node *)hash_find(orig_hash, icmp_packet->dst);
 
 	if (!orig_node)
 		goto unlock;
@@ -226,22 +240,24 @@ static ssize_t bat_socket_write(struct file *file, const char __user *buff,
 	if (batman_if->if_status != IF_ACTIVE)
 		goto dst_unreach;
 
-	memcpy(icmp_packet.orig,
+	memcpy(icmp_packet->orig,
 	       bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
 
 	if (packet_len == sizeof(struct icmp_packet_rr))
-		memcpy(icmp_packet.rr, batman_if->net_dev->dev_addr, ETH_ALEN);
+		memcpy(icmp_packet->rr, batman_if->net_dev->dev_addr, ETH_ALEN);
+
 
-	send_raw_packet((unsigned char *)&icmp_packet,
-			packet_len, batman_if, dstaddr);
+	send_skb_packet(skb, batman_if, dstaddr);
 
 	goto out;
 
 unlock:
 	spin_unlock_irqrestore(&orig_hash_lock, flags);
 dst_unreach:
-	icmp_packet.msg_type = DESTINATION_UNREACHABLE;
-	bat_socket_add_packet(socket_client, &icmp_packet, packet_len);
+	icmp_packet->msg_type = DESTINATION_UNREACHABLE;
+	bat_socket_add_packet(socket_client, icmp_packet, packet_len);
+free_skb:
+	kfree_skb(skb);
 out:
 	return len;
 }