1dfedd3b6SAndrew Lunn // SPDX-License-Identifier: GPL-2.0+ 2cf85d08fSLennert Buytenhek /* 3cf85d08fSLennert Buytenhek * net/dsa/tag_dsa.c - (Non-ethertype) DSA tagging 4e84665c9SLennert Buytenhek * Copyright (c) 2008-2009 Marvell Semiconductor 5cf85d08fSLennert Buytenhek */ 6cf85d08fSLennert Buytenhek 7cf85d08fSLennert Buytenhek #include <linux/etherdevice.h> 8cf85d08fSLennert Buytenhek #include <linux/list.h> 95a0e3ad6STejun Heo #include <linux/slab.h> 10ea5dd34bSVivien Didelot 11cf85d08fSLennert Buytenhek #include "dsa_priv.h" 12cf85d08fSLennert Buytenhek 13cf85d08fSLennert Buytenhek #define DSA_HLEN 4 14cf85d08fSLennert Buytenhek 154ed70ce9SFlorian Fainelli static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev) 16cf85d08fSLennert Buytenhek { 17d945097bSVivien Didelot struct dsa_port *dp = dsa_slave_to_port(dev); 18cf85d08fSLennert Buytenhek u8 *dsa_header; 19cf85d08fSLennert Buytenhek 20cf85d08fSLennert Buytenhek /* 21cf85d08fSLennert Buytenhek * Convert the outermost 802.1q tag to a DSA tag for tagged 22cf85d08fSLennert Buytenhek * packets, or insert a DSA tag between the addresses and 23cf85d08fSLennert Buytenhek * the ethertype field for untagged packets. 24cf85d08fSLennert Buytenhek */ 25cf85d08fSLennert Buytenhek if (skb->protocol == htons(ETH_P_8021Q)) { 26cf85d08fSLennert Buytenhek if (skb_cow_head(skb, 0) < 0) 27fe47d563SVivien Didelot return NULL; 28cf85d08fSLennert Buytenhek 29cf85d08fSLennert Buytenhek /* 30cf85d08fSLennert Buytenhek * Construct tagged FROM_CPU DSA tag from 802.1q tag. 31cf85d08fSLennert Buytenhek */ 32cf85d08fSLennert Buytenhek dsa_header = skb->data + 2 * ETH_ALEN; 33d945097bSVivien Didelot dsa_header[0] = 0x60 | dp->ds->index; 34d945097bSVivien Didelot dsa_header[1] = dp->index << 3; 35cf85d08fSLennert Buytenhek 36cf85d08fSLennert Buytenhek /* 37cf85d08fSLennert Buytenhek * Move CFI field from byte 2 to byte 1. 38cf85d08fSLennert Buytenhek */ 39cf85d08fSLennert Buytenhek if (dsa_header[2] & 0x10) { 40cf85d08fSLennert Buytenhek dsa_header[1] |= 0x01; 41cf85d08fSLennert Buytenhek dsa_header[2] &= ~0x10; 42cf85d08fSLennert Buytenhek } 43cf85d08fSLennert Buytenhek } else { 44cf85d08fSLennert Buytenhek if (skb_cow_head(skb, DSA_HLEN) < 0) 45fe47d563SVivien Didelot return NULL; 46cf85d08fSLennert Buytenhek skb_push(skb, DSA_HLEN); 47cf85d08fSLennert Buytenhek 48cf85d08fSLennert Buytenhek memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); 49cf85d08fSLennert Buytenhek 50cf85d08fSLennert Buytenhek /* 51cf85d08fSLennert Buytenhek * Construct untagged FROM_CPU DSA tag. 52cf85d08fSLennert Buytenhek */ 53cf85d08fSLennert Buytenhek dsa_header = skb->data + 2 * ETH_ALEN; 54d945097bSVivien Didelot dsa_header[0] = 0x40 | dp->ds->index; 55d945097bSVivien Didelot dsa_header[1] = dp->index << 3; 56cf85d08fSLennert Buytenhek dsa_header[2] = 0x00; 57cf85d08fSLennert Buytenhek dsa_header[3] = 0x00; 58cf85d08fSLennert Buytenhek } 59cf85d08fSLennert Buytenhek 604ed70ce9SFlorian Fainelli return skb; 61cf85d08fSLennert Buytenhek } 62cf85d08fSLennert Buytenhek 63a86d8becSFlorian Fainelli static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev, 6489e49506SFlorian Westphal struct packet_type *pt) 65cf85d08fSLennert Buytenhek { 66cf85d08fSLennert Buytenhek u8 *dsa_header; 67e84665c9SLennert Buytenhek int source_device; 68cf85d08fSLennert Buytenhek int source_port; 69cf85d08fSLennert Buytenhek 70cf85d08fSLennert Buytenhek if (unlikely(!pskb_may_pull(skb, DSA_HLEN))) 7154709795SVivien Didelot return NULL; 72cf85d08fSLennert Buytenhek 73cf85d08fSLennert Buytenhek /* 74cf85d08fSLennert Buytenhek * The ethertype field is part of the DSA header. 75cf85d08fSLennert Buytenhek */ 76cf85d08fSLennert Buytenhek dsa_header = skb->data - 2; 77cf85d08fSLennert Buytenhek 78cf85d08fSLennert Buytenhek /* 79e84665c9SLennert Buytenhek * Check that frame type is either TO_CPU or FORWARD. 80cf85d08fSLennert Buytenhek */ 81e84665c9SLennert Buytenhek if ((dsa_header[0] & 0xc0) != 0x00 && (dsa_header[0] & 0xc0) != 0xc0) 8254709795SVivien Didelot return NULL; 83cf85d08fSLennert Buytenhek 84cf85d08fSLennert Buytenhek /* 85e84665c9SLennert Buytenhek * Determine source device and port. 86cf85d08fSLennert Buytenhek */ 87e84665c9SLennert Buytenhek source_device = dsa_header[0] & 0x1f; 88cf85d08fSLennert Buytenhek source_port = (dsa_header[1] >> 3) & 0x1f; 89e84665c9SLennert Buytenhek 902231c43bSVivien Didelot skb->dev = dsa_master_find_slave(dev, source_device, source_port); 913775b1b7SVivien Didelot if (!skb->dev) 9254709795SVivien Didelot return NULL; 93cf85d08fSLennert Buytenhek 94cf85d08fSLennert Buytenhek /* 95cf85d08fSLennert Buytenhek * Convert the DSA header to an 802.1q header if the 'tagged' 96cf85d08fSLennert Buytenhek * bit in the DSA header is set. If the 'tagged' bit is clear, 97cf85d08fSLennert Buytenhek * delete the DSA header entirely. 98cf85d08fSLennert Buytenhek */ 99cf85d08fSLennert Buytenhek if (dsa_header[0] & 0x20) { 100cf85d08fSLennert Buytenhek u8 new_header[4]; 101cf85d08fSLennert Buytenhek 102cf85d08fSLennert Buytenhek /* 103cf85d08fSLennert Buytenhek * Insert 802.1q ethertype and copy the VLAN-related 104cf85d08fSLennert Buytenhek * fields, but clear the bit that will hold CFI (since 105cf85d08fSLennert Buytenhek * DSA uses that bit location for another purpose). 106cf85d08fSLennert Buytenhek */ 107cf85d08fSLennert Buytenhek new_header[0] = (ETH_P_8021Q >> 8) & 0xff; 108cf85d08fSLennert Buytenhek new_header[1] = ETH_P_8021Q & 0xff; 109cf85d08fSLennert Buytenhek new_header[2] = dsa_header[2] & ~0x10; 110cf85d08fSLennert Buytenhek new_header[3] = dsa_header[3]; 111cf85d08fSLennert Buytenhek 112cf85d08fSLennert Buytenhek /* 113cf85d08fSLennert Buytenhek * Move CFI bit from its place in the DSA header to 114cf85d08fSLennert Buytenhek * its 802.1q-designated place. 115cf85d08fSLennert Buytenhek */ 116cf85d08fSLennert Buytenhek if (dsa_header[1] & 0x01) 117cf85d08fSLennert Buytenhek new_header[2] |= 0x10; 118cf85d08fSLennert Buytenhek 119cf85d08fSLennert Buytenhek /* 120cf85d08fSLennert Buytenhek * Update packet checksum if skb is CHECKSUM_COMPLETE. 121cf85d08fSLennert Buytenhek */ 122cf85d08fSLennert Buytenhek if (skb->ip_summed == CHECKSUM_COMPLETE) { 123cf85d08fSLennert Buytenhek __wsum c = skb->csum; 124cf85d08fSLennert Buytenhek c = csum_add(c, csum_partial(new_header + 2, 2, 0)); 125cf85d08fSLennert Buytenhek c = csum_sub(c, csum_partial(dsa_header + 2, 2, 0)); 126cf85d08fSLennert Buytenhek skb->csum = c; 127cf85d08fSLennert Buytenhek } 128cf85d08fSLennert Buytenhek 129cf85d08fSLennert Buytenhek memcpy(dsa_header, new_header, DSA_HLEN); 130cf85d08fSLennert Buytenhek } else { 131cf85d08fSLennert Buytenhek /* 132cf85d08fSLennert Buytenhek * Remove DSA tag and update checksum. 133cf85d08fSLennert Buytenhek */ 134cf85d08fSLennert Buytenhek skb_pull_rcsum(skb, DSA_HLEN); 135cf85d08fSLennert Buytenhek memmove(skb->data - ETH_HLEN, 136cf85d08fSLennert Buytenhek skb->data - ETH_HLEN - DSA_HLEN, 137cf85d08fSLennert Buytenhek 2 * ETH_ALEN); 138cf85d08fSLennert Buytenhek } 139cf85d08fSLennert Buytenhek 14013edbdb6SAndrew Lunn skb->offload_fwd_mark = 1; 14113edbdb6SAndrew Lunn 142a86d8becSFlorian Fainelli return skb; 143cf85d08fSLennert Buytenhek } 144cf85d08fSLennert Buytenhek 14557fd9678SRundong Ge static int dsa_tag_flow_dissect(const struct sk_buff *skb, __be16 *proto, 14657fd9678SRundong Ge int *offset) 14757fd9678SRundong Ge { 14857fd9678SRundong Ge *offset = 4; 14957fd9678SRundong Ge *proto = ((__be16 *)skb->data)[1]; 15057fd9678SRundong Ge return 0; 15157fd9678SRundong Ge } 15257fd9678SRundong Ge 1533e8a72d1SFlorian Fainelli const struct dsa_device_ops dsa_netdev_ops = { 1543e8a72d1SFlorian Fainelli .xmit = dsa_xmit, 1553e8a72d1SFlorian Fainelli .rcv = dsa_rcv, 15657fd9678SRundong Ge .flow_dissect = dsa_tag_flow_dissect, 157a5dd3087SAndrew Lunn .overhead = DSA_HLEN, 158cf85d08fSLennert Buytenhek }; 159