| /* |
| * 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 struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev) |
| { |
| struct dsa_slave_priv *p = netdev_priv(dev); |
| u8 *dsa_header; |
| |
| /* |
| * 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) |
| return NULL; |
| |
| /* |
| * Construct tagged FROM_CPU DSA tag from 802.1q tag. |
| */ |
| dsa_header = skb->data + 2 * ETH_ALEN; |
| dsa_header[0] = 0x60 | p->dp->ds->index; |
| dsa_header[1] = p->dp->index << 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) |
| return NULL; |
| 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->dp->ds->index; |
| dsa_header[1] = p->dp->index << 3; |
| dsa_header[2] = 0x00; |
| dsa_header[3] = 0x00; |
| } |
| |
| return skb; |
| } |
| |
| static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev, |
| struct packet_type *pt) |
| { |
| struct dsa_switch_tree *dst = dev->dsa_ptr; |
| struct dsa_switch *ds; |
| u8 *dsa_header; |
| int source_device; |
| int source_port; |
| |
| if (unlikely(!pskb_may_pull(skb, DSA_HLEN))) |
| return NULL; |
| |
| /* |
| * 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) |
| return NULL; |
| |
| /* |
| * 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 >= DSA_MAX_SWITCHES) |
| return NULL; |
| |
| ds = dst->ds[source_device]; |
| if (!ds) |
| return NULL; |
| |
| if (source_port >= ds->num_ports || !ds->ports[source_port].netdev) |
| return NULL; |
| |
| /* |
| * 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].netdev; |
| |
| return skb; |
| } |
| |
| const struct dsa_device_ops dsa_netdev_ops = { |
| .xmit = dsa_xmit, |
| .rcv = dsa_rcv, |
| }; |