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