1cf85d08fSLennert Buytenhek /* 2cf85d08fSLennert Buytenhek * net/dsa/tag_dsa.c - (Non-ethertype) DSA tagging 3e84665c9SLennert Buytenhek * Copyright (c) 2008-2009 Marvell Semiconductor 4cf85d08fSLennert Buytenhek * 5cf85d08fSLennert Buytenhek * This program is free software; you can redistribute it and/or modify 6cf85d08fSLennert Buytenhek * it under the terms of the GNU General Public License as published by 7cf85d08fSLennert Buytenhek * the Free Software Foundation; either version 2 of the License, or 8cf85d08fSLennert Buytenhek * (at your option) any later version. 9cf85d08fSLennert Buytenhek */ 10cf85d08fSLennert Buytenhek 11cf85d08fSLennert Buytenhek #include <linux/etherdevice.h> 12cf85d08fSLennert Buytenhek #include <linux/list.h> 135a0e3ad6STejun Heo #include <linux/slab.h> 14ea5dd34bSVivien Didelot 15cf85d08fSLennert Buytenhek #include "dsa_priv.h" 16cf85d08fSLennert Buytenhek 17cf85d08fSLennert Buytenhek #define DSA_HLEN 4 18cf85d08fSLennert Buytenhek 194ed70ce9SFlorian Fainelli static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev) 20cf85d08fSLennert Buytenhek { 21cf85d08fSLennert Buytenhek struct dsa_slave_priv *p = netdev_priv(dev); 22cf85d08fSLennert Buytenhek u8 *dsa_header; 23cf85d08fSLennert Buytenhek 24cf85d08fSLennert Buytenhek /* 25cf85d08fSLennert Buytenhek * Convert the outermost 802.1q tag to a DSA tag for tagged 26cf85d08fSLennert Buytenhek * packets, or insert a DSA tag between the addresses and 27cf85d08fSLennert Buytenhek * the ethertype field for untagged packets. 28cf85d08fSLennert Buytenhek */ 29cf85d08fSLennert Buytenhek if (skb->protocol == htons(ETH_P_8021Q)) { 30cf85d08fSLennert Buytenhek if (skb_cow_head(skb, 0) < 0) 31fe47d563SVivien Didelot return NULL; 32cf85d08fSLennert Buytenhek 33cf85d08fSLennert Buytenhek /* 34cf85d08fSLennert Buytenhek * Construct tagged FROM_CPU DSA tag from 802.1q tag. 35cf85d08fSLennert Buytenhek */ 36cf85d08fSLennert Buytenhek dsa_header = skb->data + 2 * ETH_ALEN; 37afdcf151SVivien Didelot dsa_header[0] = 0x60 | p->dp->ds->index; 38afdcf151SVivien Didelot dsa_header[1] = p->dp->index << 3; 39cf85d08fSLennert Buytenhek 40cf85d08fSLennert Buytenhek /* 41cf85d08fSLennert Buytenhek * Move CFI field from byte 2 to byte 1. 42cf85d08fSLennert Buytenhek */ 43cf85d08fSLennert Buytenhek if (dsa_header[2] & 0x10) { 44cf85d08fSLennert Buytenhek dsa_header[1] |= 0x01; 45cf85d08fSLennert Buytenhek dsa_header[2] &= ~0x10; 46cf85d08fSLennert Buytenhek } 47cf85d08fSLennert Buytenhek } else { 48cf85d08fSLennert Buytenhek if (skb_cow_head(skb, DSA_HLEN) < 0) 49fe47d563SVivien Didelot return NULL; 50cf85d08fSLennert Buytenhek skb_push(skb, DSA_HLEN); 51cf85d08fSLennert Buytenhek 52cf85d08fSLennert Buytenhek memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); 53cf85d08fSLennert Buytenhek 54cf85d08fSLennert Buytenhek /* 55cf85d08fSLennert Buytenhek * Construct untagged FROM_CPU DSA tag. 56cf85d08fSLennert Buytenhek */ 57cf85d08fSLennert Buytenhek dsa_header = skb->data + 2 * ETH_ALEN; 58afdcf151SVivien Didelot dsa_header[0] = 0x40 | p->dp->ds->index; 59afdcf151SVivien Didelot dsa_header[1] = p->dp->index << 3; 60cf85d08fSLennert Buytenhek dsa_header[2] = 0x00; 61cf85d08fSLennert Buytenhek dsa_header[3] = 0x00; 62cf85d08fSLennert Buytenhek } 63cf85d08fSLennert Buytenhek 644ed70ce9SFlorian Fainelli return skb; 65cf85d08fSLennert Buytenhek } 66cf85d08fSLennert Buytenhek 67a86d8becSFlorian Fainelli static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev, 6889e49506SFlorian Westphal struct packet_type *pt) 69cf85d08fSLennert Buytenhek { 70e84665c9SLennert Buytenhek struct dsa_switch_tree *dst = dev->dsa_ptr; 71e84665c9SLennert Buytenhek struct dsa_switch *ds; 72cf85d08fSLennert Buytenhek u8 *dsa_header; 73e84665c9SLennert Buytenhek int source_device; 74cf85d08fSLennert Buytenhek int source_port; 75cf85d08fSLennert Buytenhek 76cf85d08fSLennert Buytenhek if (unlikely(!pskb_may_pull(skb, DSA_HLEN))) 7754709795SVivien Didelot return NULL; 78cf85d08fSLennert Buytenhek 79cf85d08fSLennert Buytenhek /* 80cf85d08fSLennert Buytenhek * The ethertype field is part of the DSA header. 81cf85d08fSLennert Buytenhek */ 82cf85d08fSLennert Buytenhek dsa_header = skb->data - 2; 83cf85d08fSLennert Buytenhek 84cf85d08fSLennert Buytenhek /* 85e84665c9SLennert Buytenhek * Check that frame type is either TO_CPU or FORWARD. 86cf85d08fSLennert Buytenhek */ 87e84665c9SLennert Buytenhek if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0) 8854709795SVivien Didelot return NULL; 89cf85d08fSLennert Buytenhek 90cf85d08fSLennert Buytenhek /* 91e84665c9SLennert Buytenhek * Determine source device and port. 92cf85d08fSLennert Buytenhek */ 93e84665c9SLennert Buytenhek source_device = dsa_header[0] & 0x1f; 94cf85d08fSLennert Buytenhek source_port = (dsa_header[1] >> 3) & 0x1f; 95e84665c9SLennert Buytenhek 96e84665c9SLennert Buytenhek /* 97e84665c9SLennert Buytenhek * Check that the source device exists and that the source 98e84665c9SLennert Buytenhek * port is a registered DSA port. 99e84665c9SLennert Buytenhek */ 100149cafd7SAndrew Lunn if (source_device >= DSA_MAX_SWITCHES) 10154709795SVivien Didelot return NULL; 102149cafd7SAndrew Lunn 103e84665c9SLennert Buytenhek ds = dst->ds[source_device]; 104149cafd7SAndrew Lunn if (!ds) 10554709795SVivien Didelot return NULL; 106149cafd7SAndrew Lunn 10726895e29SVivien Didelot if (source_port >= ds->num_ports || !ds->ports[source_port].netdev) 10854709795SVivien Didelot return NULL; 109cf85d08fSLennert Buytenhek 110cf85d08fSLennert Buytenhek /* 111cf85d08fSLennert Buytenhek * Convert the DSA header to an 802.1q header if the 'tagged' 112cf85d08fSLennert Buytenhek * bit in the DSA header is set. If the 'tagged' bit is clear, 113cf85d08fSLennert Buytenhek * delete the DSA header entirely. 114cf85d08fSLennert Buytenhek */ 115cf85d08fSLennert Buytenhek if (dsa_header[0] & 0x20) { 116cf85d08fSLennert Buytenhek u8 new_header[4]; 117cf85d08fSLennert Buytenhek 118cf85d08fSLennert Buytenhek /* 119cf85d08fSLennert Buytenhek * Insert 802.1q ethertype and copy the VLAN-related 120cf85d08fSLennert Buytenhek * fields, but clear the bit that will hold CFI (since 121cf85d08fSLennert Buytenhek * DSA uses that bit location for another purpose). 122cf85d08fSLennert Buytenhek */ 123cf85d08fSLennert Buytenhek new_header[0] = (ETH_P_8021Q >> 8) & 0xff; 124cf85d08fSLennert Buytenhek new_header[1] = ETH_P_8021Q & 0xff; 125cf85d08fSLennert Buytenhek new_header[2] = dsa_header[2] & ~0x10; 126cf85d08fSLennert Buytenhek new_header[3] = dsa_header[3]; 127cf85d08fSLennert Buytenhek 128cf85d08fSLennert Buytenhek /* 129cf85d08fSLennert Buytenhek * Move CFI bit from its place in the DSA header to 130cf85d08fSLennert Buytenhek * its 802.1q-designated place. 131cf85d08fSLennert Buytenhek */ 132cf85d08fSLennert Buytenhek if (dsa_header[1] & 0x01) 133cf85d08fSLennert Buytenhek new_header[2] |= 0x10; 134cf85d08fSLennert Buytenhek 135cf85d08fSLennert Buytenhek /* 136cf85d08fSLennert Buytenhek * Update packet checksum if skb is CHECKSUM_COMPLETE. 137cf85d08fSLennert Buytenhek */ 138cf85d08fSLennert Buytenhek if (skb->ip_summed == CHECKSUM_COMPLETE) { 139cf85d08fSLennert Buytenhek __wsum c = skb->csum; 140cf85d08fSLennert Buytenhek c = csum_add(c, csum_partial(new_header + 2, 2, 0)); 141cf85d08fSLennert Buytenhek c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0)); 142cf85d08fSLennert Buytenhek skb->csum = c; 143cf85d08fSLennert Buytenhek } 144cf85d08fSLennert Buytenhek 145cf85d08fSLennert Buytenhek memcpy(dsa_header, new_header, DSA_HLEN); 146cf85d08fSLennert Buytenhek } else { 147cf85d08fSLennert Buytenhek /* 148cf85d08fSLennert Buytenhek * Remove DSA tag and update checksum. 149cf85d08fSLennert Buytenhek */ 150cf85d08fSLennert Buytenhek skb_pull_rcsum(skb, DSA_HLEN); 151cf85d08fSLennert Buytenhek memmove(skb->data - ETH_HLEN, 152cf85d08fSLennert Buytenhek skb->data - ETH_HLEN - DSA_HLEN, 153cf85d08fSLennert Buytenhek 2 * ETH_ALEN); 154cf85d08fSLennert Buytenhek } 155cf85d08fSLennert Buytenhek 156c8b09808SAndrew Lunn skb->dev = ds->ports[source_port].netdev; 157cf85d08fSLennert Buytenhek 158a86d8becSFlorian Fainelli return skb; 159cf85d08fSLennert Buytenhek } 160cf85d08fSLennert Buytenhek 1613e8a72d1SFlorian Fainelli const struct dsa_device_ops dsa_netdev_ops = { 1623e8a72d1SFlorian Fainelli .xmit = dsa_xmit, 1633e8a72d1SFlorian Fainelli .rcv = dsa_rcv, 164cf85d08fSLennert Buytenhek }; 165