1 /* 2 * net/dsa/tag_trailer.c - Trailer tag format handling 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 static netdev_tx_t trailer_xmit(struct sk_buff *skb, struct net_device *dev) 17 { 18 struct dsa_slave_priv *p = netdev_priv(dev); 19 struct sk_buff *nskb; 20 int padlen; 21 u8 *trailer; 22 23 dev->stats.tx_packets++; 24 dev->stats.tx_bytes += skb->len; 25 26 /* 27 * We have to make sure that the trailer ends up as the very 28 * last 4 bytes of the packet. This means that we have to pad 29 * the packet to the minimum ethernet frame size, if necessary, 30 * before adding the trailer. 31 */ 32 padlen = 0; 33 if (skb->len < 60) 34 padlen = 60 - skb->len; 35 36 nskb = alloc_skb(NET_IP_ALIGN + skb->len + padlen + 4, GFP_ATOMIC); 37 if (nskb == NULL) { 38 kfree_skb(skb); 39 return NETDEV_TX_OK; 40 } 41 skb_reserve(nskb, NET_IP_ALIGN); 42 43 skb_reset_mac_header(nskb); 44 skb_set_network_header(nskb, skb_network_header(skb) - skb->head); 45 skb_set_transport_header(nskb, skb_transport_header(skb) - skb->head); 46 skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len)); 47 kfree_skb(skb); 48 49 if (padlen) { 50 u8 *pad = skb_put(nskb, padlen); 51 memset(pad, 0, padlen); 52 } 53 54 trailer = skb_put(nskb, 4); 55 trailer[0] = 0x80; 56 trailer[1] = 1 << p->port; 57 trailer[2] = 0x10; 58 trailer[3] = 0x00; 59 60 nskb->dev = p->parent->dst->master_netdev; 61 dev_queue_xmit(nskb); 62 63 return NETDEV_TX_OK; 64 } 65 66 static int trailer_rcv(struct sk_buff *skb, struct net_device *dev, 67 struct packet_type *pt, struct net_device *orig_dev) 68 { 69 struct dsa_switch_tree *dst = dev->dsa_ptr; 70 struct dsa_switch *ds; 71 u8 *trailer; 72 int source_port; 73 74 if (unlikely(dst == NULL)) 75 goto out_drop; 76 ds = dst->ds[0]; 77 78 skb = skb_unshare(skb, GFP_ATOMIC); 79 if (skb == NULL) 80 goto out; 81 82 if (skb_linearize(skb)) 83 goto out_drop; 84 85 trailer = skb_tail_pointer(skb) - 4; 86 if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 || 87 (trailer[3] & 0xef) != 0x00 || trailer[3] != 0x00) 88 goto out_drop; 89 90 source_port = trailer[1] & 7; 91 if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL) 92 goto out_drop; 93 94 pskb_trim_rcsum(skb, skb->len - 4); 95 96 skb->dev = ds->ports[source_port]; 97 skb_push(skb, ETH_HLEN); 98 skb->pkt_type = PACKET_HOST; 99 skb->protocol = eth_type_trans(skb, skb->dev); 100 101 skb->dev->stats.rx_packets++; 102 skb->dev->stats.rx_bytes += skb->len; 103 104 netif_receive_skb(skb); 105 106 return 0; 107 108 out_drop: 109 kfree_skb(skb); 110 out: 111 return 0; 112 } 113 114 const struct dsa_device_ops trailer_netdev_ops = { 115 .xmit = trailer_xmit, 116 .rcv = trailer_rcv, 117 }; 118