--- /dev/null
+/*
+ * net/dsa/tag_dsa.c - (Non-ethertype) DSA tagging
+ * Copyright (c) 2008-2009 Marvell Semiconductor
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include "dsa_priv.h"
+
+#define DSA_HLEN 4
+
+static netdev_tx_t dsa_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+ struct dsa_slave_priv *p = netdev_priv(dev);
+ u8 *dsa_header;
+
+ dev->stats.tx_packets++;
+ dev->stats.tx_bytes += skb->len;
+
+ /*
+ * Convert the outermost 802.1q tag to a DSA tag for tagged
+ * packets, or insert a DSA tag between the addresses and
+ * the ethertype field for untagged packets.
+ */
+ if (skb->protocol == htons(ETH_P_8021Q)) {
+ if (skb_cow_head(skb, 0) < 0)
+ goto out_free;
+
+ /*
+ * Construct tagged FROM_CPU DSA tag from 802.1q tag.
+ */
+ dsa_header = skb->data + 2 * ETH_ALEN;
+ dsa_header[0] = 0x60 | p->parent->index;
+ dsa_header[1] = p->port << 3;
+
+ /*
+ * Move CFI field from byte 2 to byte 1.
+ */
+ if (dsa_header[2] & 0x10) {
+ dsa_header[1] |= 0x01;
+ dsa_header[2] &= ~0x10;
+ }
+ } else {
+ if (skb_cow_head(skb, DSA_HLEN) < 0)
+ goto out_free;
+ skb_push(skb, DSA_HLEN);
+
+ memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN);
+
+ /*
+ * Construct untagged FROM_CPU DSA tag.
+ */
+ dsa_header = skb->data + 2 * ETH_ALEN;
+ dsa_header[0] = 0x40 | p->parent->index;
+ dsa_header[1] = p->port << 3;
+ dsa_header[2] = 0x00;
+ dsa_header[3] = 0x00;
+ }
+
+ skb->dev = p->parent->dst->master_netdev;
+ dev_queue_xmit(skb);
+
+ return NETDEV_TX_OK;
+
+out_free:
+ kfree_skb(skb);
+ return NETDEV_TX_OK;
+}
+
+static int dsa_rcv(struct sk_buff *skb, struct net_device *dev,
+ struct packet_type *pt, struct net_device *orig_dev)
+{
+ struct dsa_switch_tree *dst = dev->dsa_ptr;
+ struct dsa_switch *ds;
+ u8 *dsa_header;
+ int source_device;
+ int source_port;
+
+ if (unlikely(dst == NULL))
+ goto out_drop;
+
+ skb = skb_unshare(skb, GFP_ATOMIC);
+ if (skb == NULL)
+ goto out;
+
+ if (unlikely(!pskb_may_pull(skb, DSA_HLEN)))
+ goto out_drop;
+
+ /*
+ * The ethertype field is part of the DSA header.
+ */
+ dsa_header = skb->data - 2;
+
+ /*
+ * Check that frame type is either TO_CPU or FORWARD.
+ */
+ if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0)
+ goto out_drop;
+
+ /*
+ * Determine source device and port.
+ */
+ source_device = dsa_header[0] & 0x1f;
+ source_port = (dsa_header[1] >> 3) & 0x1f;
+
+ /*
+ * Check that the source device exists and that the source
+ * port is a registered DSA port.
+ */
+ if (source_device >= dst->pd->nr_chips)
+ goto out_drop;
+ ds = dst->ds[source_device];
+ if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL)
+ goto out_drop;
+
+ /*
+ * Convert the DSA header to an 802.1q header if the 'tagged'
+ * bit in the DSA header is set. If the 'tagged' bit is clear,
+ * delete the DSA header entirely.
+ */
+ if (dsa_header[0] & 0x20) {
+ u8 new_header[4];
+
+ /*
+ * Insert 802.1q ethertype and copy the VLAN-related
+ * fields, but clear the bit that will hold CFI (since
+ * DSA uses that bit location for another purpose).
+ */
+ new_header[0] = (ETH_P_8021Q >> 8) & 0xff;
+ new_header[1] = ETH_P_8021Q & 0xff;
+ new_header[2] = dsa_header[2] & ~0x10;
+ new_header[3] = dsa_header[3];
+
+ /*
+ * Move CFI bit from its place in the DSA header to
+ * its 802.1q-designated place.
+ */
+ if (dsa_header[1] & 0x01)
+ new_header[2] |= 0x10;
+
+ /*
+ * Update packet checksum if skb is CHECKSUM_COMPLETE.
+ */
+ if (skb->ip_summed == CHECKSUM_COMPLETE) {
+ __wsum c = skb->csum;
+ c = csum_add(c, csum_partial(new_header + 2, 2, 0));
+ c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0));
+ skb->csum = c;
+ }
+
+ memcpy(dsa_header, new_header, DSA_HLEN);
+ } else {
+ /*
+ * Remove DSA tag and update checksum.
+ */
+ skb_pull_rcsum(skb, DSA_HLEN);
+ memmove(skb->data - ETH_HLEN,
+ skb->data - ETH_HLEN - DSA_HLEN,
+ 2 * ETH_ALEN);
+ }
+
+ skb->dev = ds->ports[source_port];
+ skb_push(skb, ETH_HLEN);
+ skb->pkt_type = PACKET_HOST;
+ skb->protocol = eth_type_trans(skb, skb->dev);
+
+ skb->dev->stats.rx_packets++;
+ skb->dev->stats.rx_bytes += skb->len;
+
+ netif_receive_skb(skb);
+
+ return 0;
+
+out_drop:
+ kfree_skb(skb);
+out:
+ return 0;
+}
+
+const struct dsa_device_ops dsa_netdev_ops = {
+ .xmit = dsa_xmit,
+ .rcv = dsa_rcv,
+};
Code Review / kvmfornfv.git / blobdiff