1 files changed, 374 insertions, 0 deletions
diff --git a/drivers/net/can/dev/skb.c b/drivers/net/can/dev/skb.c
new file mode 100644
index 0000000000..3ebd4f779b
--- /dev/null
+++ b/drivers/net/can/dev/skb.c
@@ -0,0 +1,374 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
+ * Copyright (C) 2006 Andrey Volkov, Varma Electronics
+ * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
+ */
+
+#include <linux/can/dev.h>
+#include <linux/module.h>
+
+#define MOD_DESC "CAN device driver interface"
+
+MODULE_DESCRIPTION(MOD_DESC);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
+
+/* Local echo of CAN messages
+ *
+ * CAN network devices *should* support a local echo functionality
+ * (see Documentation/networking/can.rst). To test the handling of CAN
+ * interfaces that do not support the local echo both driver types are
+ * implemented. In the case that the driver does not support the echo
+ * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
+ * to perform the echo as a fallback solution.
+ */
+void can_flush_echo_skb(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+	struct net_device_stats *stats = &dev->stats;
+	int i;
+
+	for (i = 0; i < priv->echo_skb_max; i++) {
+		if (priv->echo_skb[i]) {
+			kfree_skb(priv->echo_skb[i]);
+			priv->echo_skb[i] = NULL;
+			stats->tx_dropped++;
+			stats->tx_aborted_errors++;
+		}
+	}
+}
+
+/* Put the skb on the stack to be looped backed locally lateron
+ *
+ * The function is typically called in the start_xmit function
+ * of the device driver. The driver must protect access to
+ * priv->echo_skb, if necessary.
+ */
+int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
+		     unsigned int idx, unsigned int frame_len)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	if (idx >= priv->echo_skb_max) {
+		netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
+			   __func__, idx, priv->echo_skb_max);
+		return -EINVAL;
+	}
+
+	/* check flag whether this packet has to be looped back */
+	if (!(dev->flags & IFF_ECHO) ||
+	    (skb->protocol != htons(ETH_P_CAN) &&
+	     skb->protocol != htons(ETH_P_CANFD) &&
+	     skb->protocol != htons(ETH_P_CANXL))) {
+		kfree_skb(skb);
+		return 0;
+	}
+
+	if (!priv->echo_skb[idx]) {
+		skb = can_create_echo_skb(skb);
+		if (!skb)
+			return -ENOMEM;
+
+		/* make settings for echo to reduce code in irq context */
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+		skb->dev = dev;
+
+		/* save frame_len to reuse it when transmission is completed */
+		can_skb_prv(skb)->frame_len = frame_len;
+
+		if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)
+			skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
+
+		skb_tx_timestamp(skb);
+
+		/* save this skb for tx interrupt echo handling */
+		priv->echo_skb[idx] = skb;
+	} else {
+		/* locking problem with netif_stop_queue() ?? */
+		netdev_err(dev, "%s: BUG! echo_skb %d is occupied!\n", __func__, idx);
+		kfree_skb(skb);
+		return -EBUSY;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(can_put_echo_skb);
+
+struct sk_buff *
+__can_get_echo_skb(struct net_device *dev, unsigned int idx,
+		   unsigned int *len_ptr, unsigned int *frame_len_ptr)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	if (idx >= priv->echo_skb_max) {
+		netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
+			   __func__, idx, priv->echo_skb_max);
+		return NULL;
+	}
+
+	if (priv->echo_skb[idx]) {
+		/* Using "struct canfd_frame::len" for the frame
+		 * length is supported on both CAN and CANFD frames.
+		 */
+		struct sk_buff *skb = priv->echo_skb[idx];
+		struct can_skb_priv *can_skb_priv = can_skb_prv(skb);
+
+		if (skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)
+			skb_tstamp_tx(skb, skb_hwtstamps(skb));
+
+		/* get the real payload length for netdev statistics */
+		*len_ptr = can_skb_get_data_len(skb);
+
+		if (frame_len_ptr)
+			*frame_len_ptr = can_skb_priv->frame_len;
+
+		priv->echo_skb[idx] = NULL;
+
+		if (skb->pkt_type == PACKET_LOOPBACK) {
+			skb->pkt_type = PACKET_BROADCAST;
+		} else {
+			dev_consume_skb_any(skb);
+			return NULL;
+		}
+
+		return skb;
+	}
+
+	return NULL;
+}
+
+/* Get the skb from the stack and loop it back locally
+ *
+ * The function is typically called when the TX done interrupt
+ * is handled in the device driver. The driver must protect
+ * access to priv->echo_skb, if necessary.
+ */
+unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx,
+			      unsigned int *frame_len_ptr)
+{
+	struct sk_buff *skb;
+	unsigned int len;
+
+	skb = __can_get_echo_skb(dev, idx, &len, frame_len_ptr);
+	if (!skb)
+		return 0;
+
+	skb_get(skb);
+	if (netif_rx(skb) == NET_RX_SUCCESS)
+		dev_consume_skb_any(skb);
+	else
+		dev_kfree_skb_any(skb);
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(can_get_echo_skb);
+
+/* Remove the skb from the stack and free it.
+ *
+ * The function is typically called when TX failed.
+ */
+void can_free_echo_skb(struct net_device *dev, unsigned int idx,
+		       unsigned int *frame_len_ptr)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	if (idx >= priv->echo_skb_max) {
+		netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
+			   __func__, idx, priv->echo_skb_max);
+		return;
+	}
+
+	if (priv->echo_skb[idx]) {
+		struct sk_buff *skb = priv->echo_skb[idx];
+		struct can_skb_priv *can_skb_priv = can_skb_prv(skb);
+
+		if (frame_len_ptr)
+			*frame_len_ptr = can_skb_priv->frame_len;
+
+		dev_kfree_skb_any(skb);
+		priv->echo_skb[idx] = NULL;
+	}
+}
+EXPORT_SYMBOL_GPL(can_free_echo_skb);
+
+/* fill common values for CAN sk_buffs */
+static void init_can_skb_reserve(struct sk_buff *skb)
+{
+	skb->pkt_type = PACKET_BROADCAST;
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+	skb_reset_mac_header(skb);
+	skb_reset_network_header(skb);
+	skb_reset_transport_header(skb);
+
+	can_skb_reserve(skb);
+	can_skb_prv(skb)->skbcnt = 0;
+}
+
+struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
+{
+	struct sk_buff *skb;
+
+	skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
+			       sizeof(struct can_frame));
+	if (unlikely(!skb)) {
+		*cf = NULL;
+
+		return NULL;
+	}
+
+	skb->protocol = htons(ETH_P_CAN);
+	init_can_skb_reserve(skb);
+	can_skb_prv(skb)->ifindex = dev->ifindex;
+
+	*cf = skb_put_zero(skb, sizeof(struct can_frame));
+
+	return skb;
+}
+EXPORT_SYMBOL_GPL(alloc_can_skb);
+
+struct sk_buff *alloc_canfd_skb(struct net_device *dev,
+				struct canfd_frame **cfd)
+{
+	struct sk_buff *skb;
+
+	skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
+			       sizeof(struct canfd_frame));
+	if (unlikely(!skb)) {
+		*cfd = NULL;
+
+		return NULL;
+	}
+
+	skb->protocol = htons(ETH_P_CANFD);
+	init_can_skb_reserve(skb);
+	can_skb_prv(skb)->ifindex = dev->ifindex;
+
+	*cfd = skb_put_zero(skb, sizeof(struct canfd_frame));
+
+	/* set CAN FD flag by default */
+	(*cfd)->flags = CANFD_FDF;
+
+	return skb;
+}
+EXPORT_SYMBOL_GPL(alloc_canfd_skb);
+
+struct sk_buff *alloc_canxl_skb(struct net_device *dev,
+				struct canxl_frame **cxl,
+				unsigned int data_len)
+{
+	struct sk_buff *skb;
+
+	if (data_len < CANXL_MIN_DLEN || data_len > CANXL_MAX_DLEN)
+		goto out_error;
+
+	skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
+			       CANXL_HDR_SIZE + data_len);
+	if (unlikely(!skb))
+		goto out_error;
+
+	skb->protocol = htons(ETH_P_CANXL);
+	init_can_skb_reserve(skb);
+	can_skb_prv(skb)->ifindex = dev->ifindex;
+
+	*cxl = skb_put_zero(skb, CANXL_HDR_SIZE + data_len);
+
+	/* set CAN XL flag and length information by default */
+	(*cxl)->flags = CANXL_XLF;
+	(*cxl)->len = data_len;
+
+	return skb;
+
+out_error:
+	*cxl = NULL;
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(alloc_canxl_skb);
+
+struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
+{
+	struct sk_buff *skb;
+
+	skb = alloc_can_skb(dev, cf);
+	if (unlikely(!skb))
+		return NULL;
+
+	(*cf)->can_id = CAN_ERR_FLAG;
+	(*cf)->len = CAN_ERR_DLC;
+
+	return skb;
+}
+EXPORT_SYMBOL_GPL(alloc_can_err_skb);
+
+/* Check for outgoing skbs that have not been created by the CAN subsystem */
+static bool can_skb_headroom_valid(struct net_device *dev, struct sk_buff *skb)
+{
+	/* af_packet creates a headroom of HH_DATA_MOD bytes which is fine */
+	if (WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct can_skb_priv)))
+		return false;
+
+	/* af_packet does not apply CAN skb specific settings */
+	if (skb->ip_summed == CHECKSUM_NONE) {
+		/* init headroom */
+		can_skb_prv(skb)->ifindex = dev->ifindex;
+		can_skb_prv(skb)->skbcnt = 0;
+
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+		/* perform proper loopback on capable devices */
+		if (dev->flags & IFF_ECHO)
+			skb->pkt_type = PACKET_LOOPBACK;
+		else
+			skb->pkt_type = PACKET_HOST;
+
+		skb_reset_mac_header(skb);
+		skb_reset_network_header(skb);
+		skb_reset_transport_header(skb);
+
+		/* set CANFD_FDF flag for CAN FD frames */
+		if (can_is_canfd_skb(skb)) {
+			struct canfd_frame *cfd;
+
+			cfd = (struct canfd_frame *)skb->data;
+			cfd->flags |= CANFD_FDF;
+		}
+	}
+
+	return true;
+}
+
+/* Drop a given socketbuffer if it does not contain a valid CAN frame. */
+bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb)
+{
+	switch (ntohs(skb->protocol)) {
+	case ETH_P_CAN:
+		if (!can_is_can_skb(skb))
+			goto inval_skb;
+		break;
+
+	case ETH_P_CANFD:
+		if (!can_is_canfd_skb(skb))
+			goto inval_skb;
+		break;
+
+	case ETH_P_CANXL:
+		if (!can_is_canxl_skb(skb))
+			goto inval_skb;
+		break;
+
+	default:
+		goto inval_skb;
+	}
+
+	if (!can_skb_headroom_valid(dev, skb))
+		goto inval_skb;
+
+	return false;
+
+inval_skb:
+	kfree_skb(skb);
+	dev->stats.tx_dropped++;
+	return true;
+}
+EXPORT_SYMBOL_GPL(can_dropped_invalid_skb);