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