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/netdevice.h> 14#include <linux/slab.h> 15#include "dsa_priv.h" 16 17#define DSA_HLEN 4 18#define EDSA_HLEN 8 19 20netdev_tx_t edsa_xmit(struct sk_buff *skb, struct net_device *dev) 21{ 22 struct dsa_slave_priv *p = netdev_priv(dev); 23 u8 *edsa_header; 24 25 dev->stats.tx_packets++; 26 dev->stats.tx_bytes += skb->len; 27 28 /* 29 * Convert the outermost 802.1q tag to a DSA tag and prepend 30 * a DSA ethertype field is the packet is tagged, or insert 31 * a DSA ethertype plus DSA tag between the addresses and the 32 * current ethertype field if the packet is untagged. 33 */ 34 if (skb->protocol == htons(ETH_P_8021Q)) { 35 if (skb_cow_head(skb, DSA_HLEN) < 0) 36 goto out_free; 37 skb_push(skb, DSA_HLEN); 38 39 memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); 40 41 /* 42 * Construct tagged FROM_CPU DSA tag from 802.1q tag. 43 */ 44 edsa_header = skb->data + 2 * ETH_ALEN; 45 edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; 46 edsa_header[1] = ETH_P_EDSA & 0xff; 47 edsa_header[2] = 0x00; 48 edsa_header[3] = 0x00; 49 edsa_header[4] = 0x60 | p->parent->index; 50 edsa_header[5] = p->port << 3; 51 52 /* 53 * Move CFI field from byte 6 to byte 5. 54 */ 55 if (edsa_header[6] & 0x10) { 56 edsa_header[5] |= 0x01; 57 edsa_header[6] &= ~0x10; 58 } 59 } else { 60 if (skb_cow_head(skb, EDSA_HLEN) < 0) 61 goto out_free; 62 skb_push(skb, EDSA_HLEN); 63 64 memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN); 65 66 /* 67 * Construct untagged FROM_CPU DSA tag. 68 */ 69 edsa_header = skb->data + 2 * ETH_ALEN; 70 edsa_header[0] = (ETH_P_EDSA >> 8) & 0xff; 71 edsa_header[1] = ETH_P_EDSA & 0xff; 72 edsa_header[2] = 0x00; 73 edsa_header[3] = 0x00; 74 edsa_header[4] = 0x40 | p->parent->index; 75 edsa_header[5] = p->port << 3; 76 edsa_header[6] = 0x00; 77 edsa_header[7] = 0x00; 78 } 79 80 skb->protocol = htons(ETH_P_EDSA); 81 82 skb->dev = p->parent->dst->master_netdev; 83 dev_queue_xmit(skb); 84 85 return NETDEV_TX_OK; 86 87out_free: 88 kfree_skb(skb); 89 return NETDEV_TX_OK; 90} 91 92static int edsa_rcv(struct sk_buff *skb, struct net_device *dev, 93 struct packet_type *pt, struct net_device *orig_dev) 94{ 95 struct dsa_switch_tree *dst = dev->dsa_ptr; 96 struct dsa_switch *ds; 97 u8 *edsa_header; 98 int source_device; 99 int source_port; 100 101 if (unlikely(dst == NULL)) 102 goto out_drop; 103 104 skb = skb_unshare(skb, GFP_ATOMIC); 105 if (skb == NULL) 106 goto out; 107 108 if (unlikely(!pskb_may_pull(skb, EDSA_HLEN))) 109 goto out_drop; 110 111 /* 112 * Skip the two null bytes after the ethertype. 113 */ 114 edsa_header = skb->data + 2; 115 116 /* 117 * Check that frame type is either TO_CPU or FORWARD. 118 */ 119 if ((edsa_header[0] & 0xc0) != 0x00 && (edsa_header[0] & 0xc0) != 0xc0) 120 goto out_drop; 121 122 /* 123 * Determine source device and port. 124 */ 125 source_device = edsa_header[0] & 0x1f; 126 source_port = (edsa_header[1] >> 3) & 0x1f; 127 128 /* 129 * Check that the source device exists and that the source 130 * port is a registered DSA port. 131 */ 132 if (source_device >= dst->pd->nr_chips) 133 goto out_drop; 134 ds = dst->ds[source_device]; 135 if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL) 136 goto out_drop; 137 138 /* 139 * If the 'tagged' bit is set, convert the DSA tag to a 802.1q 140 * tag and delete the ethertype part. If the 'tagged' bit is 141 * clear, delete the ethertype and the DSA tag parts. 142 */ 143 if (edsa_header[0] & 0x20) { 144 u8 new_header[4]; 145 146 /* 147 * Insert 802.1q ethertype and copy the VLAN-related 148 * fields, but clear the bit that will hold CFI (since 149 * DSA uses that bit location for another purpose). 150 */ 151 new_header[0] = (ETH_P_8021Q >> 8) & 0xff; 152 new_header[1] = ETH_P_8021Q & 0xff; 153 new_header[2] = edsa_header[2] & ~0x10; 154 new_header[3] = edsa_header[3]; 155 156 /* 157 * Move CFI bit from its place in the DSA header to 158 * its 802.1q-designated place. 159 */ 160 if (edsa_header[1] & 0x01) 161 new_header[2] |= 0x10; 162 163 skb_pull_rcsum(skb, DSA_HLEN); 164 165 /* 166 * Update packet checksum if skb is CHECKSUM_COMPLETE. 167 */ 168 if (skb->ip_summed == CHECKSUM_COMPLETE) { 169 __wsum c = skb->csum; 170 c = csum_add(c, csum_partial(new_header + 2, 2, 0)); 171 c = csum_sub(c, csum_partial(edsa_header + 2, 2, 0)); 172 skb->csum = c; 173 } 174 175 memcpy(edsa_header, new_header, DSA_HLEN); 176 177 memmove(skb->data - ETH_HLEN, 178 skb->data - ETH_HLEN - DSA_HLEN, 179 2 * ETH_ALEN); 180 } else { 181 /* 182 * Remove DSA tag and update checksum. 183 */ 184 skb_pull_rcsum(skb, EDSA_HLEN); 185 memmove(skb->data - ETH_HLEN, 186 skb->data - ETH_HLEN - EDSA_HLEN, 187 2 * ETH_ALEN); 188 } 189 190 skb->dev = ds->ports[source_port]; 191 skb_push(skb, ETH_HLEN); 192 skb->pkt_type = PACKET_HOST; 193 skb->protocol = eth_type_trans(skb, skb->dev); 194 195 skb->dev->stats.rx_packets++; 196 skb->dev->stats.rx_bytes += skb->len; 197 198 netif_receive_skb(skb); 199 200 return 0; 201 202out_drop: 203 kfree_skb(skb); 204out: 205 return 0; 206} 207 208static struct packet_type edsa_packet_type __read_mostly = { 209 .type = cpu_to_be16(ETH_P_EDSA), 210 .func = edsa_rcv, 211}; 212 213static int __init edsa_init_module(void) 214{ 215 dev_add_pack(&edsa_packet_type); 216 return 0; 217} 218module_init(edsa_init_module); 219 220static void __exit edsa_cleanup_module(void) 221{ 222 dev_remove_pack(&edsa_packet_type); 223} 224module_exit(edsa_cleanup_module); 225