1/* 2 * net/dsa/tag_dsa.c - (Non-ethertype) DSA tagging 3 * Copyright (c) 2008-2009 Marvell Semiconductor 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 */ 10 11#include <linux/etherdevice.h> 12#include <linux/list.h> 13#include <linux/slab.h> 14#include "dsa_priv.h" 15 16#define DSA_HLEN 4 17 18static netdev_tx_t dsa_xmit(struct sk_buff *skb, struct net_device *dev) 19{ 20 struct dsa_slave_priv *p = netdev_priv(dev); 21 u8 *dsa_header; 22 23 dev->stats.tx_packets++; 24 dev->stats.tx_bytes += skb->len; 25 26 /* 27 * Convert the outermost 802.1q tag to a DSA tag for tagged 28 * packets, or insert a DSA tag between the addresses and 29 * the ethertype field for untagged packets. 30 */ 31 if (skb->protocol == htons(ETH_P_8021Q)) { 32 if (skb_cow_head(skb, 0) < 0) 33 goto out_free; 34 35 /* 36 * Construct tagged FROM_CPU DSA tag from 802.1q tag. 37 */ 38 dsa_header = skb->data + 2 * ETH_ALEN; 39 dsa_header[0] = 0x60 | p->parent->index; 40 dsa_header[1] = p->port << 3; 41 42 /* 43 * Move CFI field from byte 2 to byte 1. 44 */ 45 if (dsa_header[2] & 0x10) { 46 dsa_header[1] |= 0x01; 47 dsa_header[2] &= ~0x10; 48 } 49 } else { 50 if (skb_cow_head(skb, DSA_HLEN) < 0) 51 goto out_free; 52 skb_push(skb, DSA_HLEN); 53 54 memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); 55 56 /* 57 * Construct untagged FROM_CPU DSA tag. 58 */ 59 dsa_header = skb->data + 2 * ETH_ALEN; 60 dsa_header[0] = 0x40 | p->parent->index; 61 dsa_header[1] = p->port << 3; 62 dsa_header[2] = 0x00; 63 dsa_header[3] = 0x00; 64 } 65 66 skb->dev = p->parent->dst->master_netdev; 67 dev_queue_xmit(skb); 68 69 return NETDEV_TX_OK; 70 71out_free: 72 kfree_skb(skb); 73 return NETDEV_TX_OK; 74} 75 76static int dsa_rcv(struct sk_buff *skb, struct net_device *dev, 77 struct packet_type *pt, struct net_device *orig_dev) 78{ 79 struct dsa_switch_tree *dst = dev->dsa_ptr; 80 struct dsa_switch *ds; 81 u8 *dsa_header; 82 int source_device; 83 int source_port; 84 85 if (unlikely(dst == NULL)) 86 goto out_drop; 87 88 skb = skb_unshare(skb, GFP_ATOMIC); 89 if (skb == NULL) 90 goto out; 91 92 if (unlikely(!pskb_may_pull(skb, DSA_HLEN))) 93 goto out_drop; 94 95 /* 96 * The ethertype field is part of the DSA header. 97 */ 98 dsa_header = skb->data - 2; 99 100 /* 101 * Check that frame type is either TO_CPU or FORWARD. 102 */ 103 if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0) 104 goto out_drop; 105 106 /* 107 * Determine source device and port. 108 */ 109 source_device = dsa_header[0] & 0x1f; 110 source_port = (dsa_header[1] >> 3) & 0x1f; 111 112 /* 113 * Check that the source device exists and that the source 114 * port is a registered DSA port. 115 */ 116 if (source_device >= dst->pd->nr_chips) 117 goto out_drop; 118 ds = dst->ds[source_device]; 119 if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL) 120 goto out_drop; 121 122 /* 123 * Convert the DSA header to an 802.1q header if the 'tagged' 124 * bit in the DSA header is set. If the 'tagged' bit is clear, 125 * delete the DSA header entirely. 126 */ 127 if (dsa_header[0] & 0x20) { 128 u8 new_header[4]; 129 130 /* 131 * Insert 802.1q ethertype and copy the VLAN-related 132 * fields, but clear the bit that will hold CFI (since 133 * DSA uses that bit location for another purpose). 134 */ 135 new_header[0] = (ETH_P_8021Q >> 8) & 0xff; 136 new_header[1] = ETH_P_8021Q & 0xff; 137 new_header[2] = dsa_header[2] & ~0x10; 138 new_header[3] = dsa_header[3]; 139 140 /* 141 * Move CFI bit from its place in the DSA header to 142 * its 802.1q-designated place. 143 */ 144 if (dsa_header[1] & 0x01) 145 new_header[2] |= 0x10; 146 147 /* 148 * Update packet checksum if skb is CHECKSUM_COMPLETE. 149 */ 150 if (skb->ip_summed == CHECKSUM_COMPLETE) { 151 __wsum c = skb->csum; 152 c = csum_add(c, csum_partial(new_header + 2, 2, 0)); 153 c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0)); 154 skb->csum = c; 155 } 156 157 memcpy(dsa_header, new_header, DSA_HLEN); 158 } else { 159 /* 160 * Remove DSA tag and update checksum. 161 */ 162 skb_pull_rcsum(skb, DSA_HLEN); 163 memmove(skb->data - ETH_HLEN, 164 skb->data - ETH_HLEN - DSA_HLEN, 165 2 * ETH_ALEN); 166 } 167 168 skb->dev = ds->ports[source_port]; 169 skb_push(skb, ETH_HLEN); 170 skb->pkt_type = PACKET_HOST; 171 skb->protocol = eth_type_trans(skb, skb->dev); 172 173 skb->dev->stats.rx_packets++; 174 skb->dev->stats.rx_bytes += skb->len; 175 176 netif_receive_skb(skb); 177 178 return 0; 179 180out_drop: 181 kfree_skb(skb); 182out: 183 return 0; 184} 185 186const struct dsa_device_ops dsa_netdev_ops = { 187 .xmit = dsa_xmit, 188 .rcv = dsa_rcv, 189}; 190