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 { 21d945097bSVivien Didelot struct dsa_port *dp = dsa_slave_to_port(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; 37d945097bSVivien Didelot dsa_header[0] = 0x60 | dp->ds->index; 38d945097bSVivien Didelot dsa_header[1] = 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; 58d945097bSVivien Didelot dsa_header[0] = 0x40 | dp->ds->index; 59d945097bSVivien Didelot dsa_header[1] = 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 { 70cf85d08fSLennert Buytenhek u8 *dsa_header; 71e84665c9SLennert Buytenhek int source_device; 72cf85d08fSLennert Buytenhek int source_port; 73cf85d08fSLennert Buytenhek 74cf85d08fSLennert Buytenhek if (unlikely(!pskb_may_pull(skb, DSA_HLEN))) 7554709795SVivien Didelot return NULL; 76cf85d08fSLennert Buytenhek 77cf85d08fSLennert Buytenhek /* 78cf85d08fSLennert Buytenhek * The ethertype field is part of the DSA header. 79cf85d08fSLennert Buytenhek */ 80cf85d08fSLennert Buytenhek dsa_header = skb->data - 2; 81cf85d08fSLennert Buytenhek 82cf85d08fSLennert Buytenhek /* 83e84665c9SLennert Buytenhek * Check that frame type is either TO_CPU or FORWARD. 84cf85d08fSLennert Buytenhek */ 85e84665c9SLennert Buytenhek if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0) 8654709795SVivien Didelot return NULL; 87cf85d08fSLennert Buytenhek 88cf85d08fSLennert Buytenhek /* 89e84665c9SLennert Buytenhek * Determine source device and port. 90cf85d08fSLennert Buytenhek */ 91e84665c9SLennert Buytenhek source_device = dsa_header[0] & 0x1f; 92cf85d08fSLennert Buytenhek source_port = (dsa_header[1] >> 3) & 0x1f; 93e84665c9SLennert Buytenhek 942231c43bSVivien Didelot skb->dev = dsa_master_find_slave(dev, source_device, source_port); 953775b1b7SVivien Didelot if (!skb->dev) 9654709795SVivien Didelot return NULL; 97cf85d08fSLennert Buytenhek 98cf85d08fSLennert Buytenhek /* 99cf85d08fSLennert Buytenhek * Convert the DSA header to an 802.1q header if the 'tagged' 100cf85d08fSLennert Buytenhek * bit in the DSA header is set. If the 'tagged' bit is clear, 101cf85d08fSLennert Buytenhek * delete the DSA header entirely. 102cf85d08fSLennert Buytenhek */ 103cf85d08fSLennert Buytenhek if (dsa_header[0] & 0x20) { 104cf85d08fSLennert Buytenhek u8 new_header[4]; 105cf85d08fSLennert Buytenhek 106cf85d08fSLennert Buytenhek /* 107cf85d08fSLennert Buytenhek * Insert 802.1q ethertype and copy the VLAN-related 108cf85d08fSLennert Buytenhek * fields, but clear the bit that will hold CFI (since 109cf85d08fSLennert Buytenhek * DSA uses that bit location for another purpose). 110cf85d08fSLennert Buytenhek */ 111cf85d08fSLennert Buytenhek new_header[0] = (ETH_P_8021Q >> 8) & 0xff; 112cf85d08fSLennert Buytenhek new_header[1] = ETH_P_8021Q & 0xff; 113cf85d08fSLennert Buytenhek new_header[2] = dsa_header[2] & ~0x10; 114cf85d08fSLennert Buytenhek new_header[3] = dsa_header[3]; 115cf85d08fSLennert Buytenhek 116cf85d08fSLennert Buytenhek /* 117cf85d08fSLennert Buytenhek * Move CFI bit from its place in the DSA header to 118cf85d08fSLennert Buytenhek * its 802.1q-designated place. 119cf85d08fSLennert Buytenhek */ 120cf85d08fSLennert Buytenhek if (dsa_header[1] & 0x01) 121cf85d08fSLennert Buytenhek new_header[2] |= 0x10; 122cf85d08fSLennert Buytenhek 123cf85d08fSLennert Buytenhek /* 124cf85d08fSLennert Buytenhek * Update packet checksum if skb is CHECKSUM_COMPLETE. 125cf85d08fSLennert Buytenhek */ 126cf85d08fSLennert Buytenhek if (skb->ip_summed == CHECKSUM_COMPLETE) { 127cf85d08fSLennert Buytenhek __wsum c = skb->csum; 128cf85d08fSLennert Buytenhek c = csum_add(c, csum_partial(new_header + 2, 2, 0)); 129cf85d08fSLennert Buytenhek c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0)); 130cf85d08fSLennert Buytenhek skb->csum = c; 131cf85d08fSLennert Buytenhek } 132cf85d08fSLennert Buytenhek 133cf85d08fSLennert Buytenhek memcpy(dsa_header, new_header, DSA_HLEN); 134cf85d08fSLennert Buytenhek } else { 135cf85d08fSLennert Buytenhek /* 136cf85d08fSLennert Buytenhek * Remove DSA tag and update checksum. 137cf85d08fSLennert Buytenhek */ 138cf85d08fSLennert Buytenhek skb_pull_rcsum(skb, DSA_HLEN); 139cf85d08fSLennert Buytenhek memmove(skb->data - ETH_HLEN, 140cf85d08fSLennert Buytenhek skb->data - ETH_HLEN - DSA_HLEN, 141cf85d08fSLennert Buytenhek 2 * ETH_ALEN); 142cf85d08fSLennert Buytenhek } 143cf85d08fSLennert Buytenhek 14413edbdb6SAndrew Lunn skb->offload_fwd_mark = 1; 14513edbdb6SAndrew Lunn 146a86d8becSFlorian Fainelli return skb; 147cf85d08fSLennert Buytenhek } 148cf85d08fSLennert Buytenhek 14957fd9678SRundong Ge static int dsa_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto, 15057fd9678SRundong Ge int *offset) 15157fd9678SRundong Ge { 15257fd9678SRundong Ge *offset = 4; 15357fd9678SRundong Ge *proto = ((__be16 *)skb->data)[1]; 15457fd9678SRundong Ge return 0; 15557fd9678SRundong Ge } 15657fd9678SRundong Ge 1573e8a72d1SFlorian Fainelli const struct dsa_device_ops dsa_netdev_ops = { 1583e8a72d1SFlorian Fainelli .xmit = dsa_xmit, 1593e8a72d1SFlorian Fainelli .rcv = dsa_rcv, 16057fd9678SRundong Ge .flow_dissect = dsa_tag_flow_dissect, 161a5dd3087SAndrew Lunn .overhead = DSA_HLEN, 162cf85d08fSLennert Buytenhek }; 163