1/* 2 * net/dsa/tag_edsa.c - 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#define EDSA_HLEN 8 18 19static netdev_tx_t edsa_xmit(struct sk_buff *skb, struct net_device *dev) 20{ 21 struct dsa_slave_priv *p = netdev_priv(dev); 22 u8 *edsa_header; 23 24 dev->stats.tx_packets++; 25 dev->stats.tx_bytes += skb->len; 26 27 /* 28 * Convert the outermost 802.1q tag to a DSA tag and prepend 29 * a DSA ethertype field is the packet is tagged, or insert 30 * a DSA ethertype plus DSA tag between the addresses and the 31 * current ethertype field if the packet is untagged. 32 */ 33 if (skb->protocol == htons(ETH_P_8021Q)) { 34 if (skb_cow_head(skb, DSA_HLEN) < 0) 35 goto out_free; 36 skb_push(skb, DSA_HLEN); 37 38 memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); 39 40 /* 41 * Construct tagged FROM_CPU DSA tag from 802.1q tag. 42 */ 43 edsa_header = skb->data + 2 * ETH_ALEN; 44 edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; 45 edsa_header[1] = ETH_P_EDSA & 0xff; 46 edsa_header[2] = 0x00; 47 edsa_header[3] = 0x00; 48 edsa_header[4] = 0x60 | p->parent->index; 49 edsa_header[5] = p->port << 3; 50 51 /* 52 * Move CFI field from byte 6 to byte 5. 53 */ 54 if (edsa_header[6] & 0x10) { 55 edsa_header[5] |= 0x01; 56 edsa_header[6] &= ~0x10; 57 } 58 } else { 59 if (skb_cow_head(skb, EDSA_HLEN) < 0) 60 goto out_free; 61 skb_push(skb, EDSA_HLEN); 62 63 memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN); 64 65 /* 66 * Construct untagged FROM_CPU DSA tag. 67 */ 68 edsa_header = skb->data + 2 * ETH_ALEN; 69 edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; 70 edsa_header[1] = ETH_P_EDSA & 0xff; 71 edsa_header[2] = 0x00; 72 edsa_header[3] = 0x00; 73 edsa_header[4] = 0x40 | p->parent->index; 74 edsa_header[5] = p->port << 3; 75 edsa_header[6] = 0x00; 76 edsa_header[7] = 0x00; 77 } 78 79 skb->protocol = htons(ETH_P_EDSA); 80 81 skb->dev = p->parent->dst->master_netdev; 82 dev_queue_xmit(skb); 83 84 return NETDEV_TX_OK; 85 86out_free: 87 kfree_skb(skb); 88 return NETDEV_TX_OK; 89} 90 91static int edsa_rcv(struct sk_buff *skb, struct net_device *dev, 92 struct packet_type *pt, struct net_device *orig_dev) 93{ 94 struct dsa_switch_tree *dst = dev->dsa_ptr; 95 struct dsa_switch *ds; 96 u8 *edsa_header; 97 int source_device; 98 int source_port; 99 100 if (unlikely(dst == NULL)) 101 goto out_drop; 102 103 skb = skb_unshare(skb, GFP_ATOMIC); 104 if (skb == NULL) 105 goto out; 106 107 if (unlikely(!pskb_may_pull(skb, EDSA_HLEN))) 108 goto out_drop; 109 110 /* 111 * Skip the two null bytes after the ethertype. 112 */ 113 edsa_header = skb->data + 2; 114 115 /* 116 * Check that frame type is either TO_CPU or FORWARD. 117 */ 118 if ((edsa_header[0] & 0xc0) != 0x00 && (edsa_header[0] & 0xc0) != 0xc0) 119 goto out_drop; 120 121 /* 122 * Determine source device and port. 123 */ 124 source_device = edsa_header[0] & 0x1f; 125 source_port = (edsa_header[1] >> 3) & 0x1f; 126 127 /* 128 * Check that the source device exists and that the source 129 * port is a registered DSA port. 130 */ 131 if (source_device >= dst->pd->nr_chips) 132 goto out_drop; 133 ds = dst->ds[source_device]; 134 if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL) 135 goto out_drop; 136 137 /* 138 * If the 'tagged' bit is set, convert the DSA tag to a 802.1q 139 * tag and delete the ethertype part. If the 'tagged' bit is 140 * clear, delete the ethertype and the DSA tag parts. 141 */ 142 if (edsa_header[0] & 0x20) { 143 u8 new_header[4]; 144 145 /* 146 * Insert 802.1q ethertype and copy the VLAN-related 147 * fields, but clear the bit that will hold CFI (since 148 * DSA uses that bit location for another purpose). 149 */ 150 new_header[0] = (ETH_P_8021Q >> 8) & 0xff; 151 new_header[1] = ETH_P_8021Q & 0xff; 152 new_header[2] = edsa_header[2] & ~0x10; 153 new_header[3] = edsa_header[3]; 154 155 /* 156 * Move CFI bit from its place in the DSA header to 157 * its 802.1q-designated place. 158 */ 159 if (edsa_header[1] & 0x01) 160 new_header[2] |= 0x10; 161 162 skb_pull_rcsum(skb, DSA_HLEN); 163 164 /* 165 * Update packet checksum if skb is CHECKSUM_COMPLETE. 166 */ 167 if (skb->ip_summed == CHECKSUM_COMPLETE) { 168 __wsum c = skb->csum; 169 c = csum_add(c, csum_partial(new_header + 2, 2, 0)); 170 c = csum_sub(c, csum_partial(edsa_header + 2, 2, 0)); 171 skb->csum = c; 172 } 173 174 memcpy(edsa_header, new_header, DSA_HLEN); 175 176 memmove(skb->data - ETH_HLEN, 177 skb->data - ETH_HLEN - DSA_HLEN, 178 2 * ETH_ALEN); 179 } else { 180 /* 181 * Remove DSA tag and update checksum. 182 */ 183 skb_pull_rcsum(skb, EDSA_HLEN); 184 memmove(skb->data - ETH_HLEN, 185 skb->data - ETH_HLEN - EDSA_HLEN, 186 2 * ETH_ALEN); 187 } 188 189 skb->dev = ds->ports[source_port]; 190 skb_push(skb, ETH_HLEN); 191 skb->pkt_type = PACKET_HOST; 192 skb->protocol = eth_type_trans(skb, skb->dev); 193 194 skb->dev->stats.rx_packets++; 195 skb->dev->stats.rx_bytes += skb->len; 196 197 netif_receive_skb(skb); 198 199 return 0; 200 201out_drop: 202 kfree_skb(skb); 203out: 204 return 0; 205} 206 207const struct dsa_device_ops edsa_netdev_ops = { 208 .xmit = edsa_xmit, 209 .rcv = edsa_rcv, 210}; 211