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/netdevice.h> 14 #include <linux/slab.h> 15 #include "dsa_priv.h" 16 17 netdev_tx_t trailer_xmit(struct sk_buff *skb, struct net_device *dev) 18 { 19 struct dsa_slave_priv *p = netdev_priv(dev); 20 struct sk_buff *nskb; 21 int padlen; 22 u8 *trailer; 23 24 dev->stats.tx_packets++; 25 dev->stats.tx_bytes += skb->len; 26 27 /* 28 * We have to make sure that the trailer ends up as the very 29 * last 4 bytes of the packet. This means that we have to pad 30 * the packet to the minimum ethernet frame size, if necessary, 31 * before adding the trailer. 32 */ 33 padlen = 0; 34 if (skb->len < 60) 35 padlen = 60 - skb->len; 36 37 nskb = alloc_skb(NET_IP_ALIGN + skb->len + padlen + 4, GFP_ATOMIC); 38 if (nskb == NULL) { 39 kfree_skb(skb); 40 return NETDEV_TX_OK; 41 } 42 skb_reserve(nskb, NET_IP_ALIGN); 43 44 skb_reset_mac_header(nskb); 45 skb_set_network_header(nskb, skb_network_header(skb) - skb->head); 46 skb_set_transport_header(nskb, skb_transport_header(skb) - skb->head); 47 skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len)); 48 kfree_skb(skb); 49 50 if (padlen) { 51 u8 *pad = skb_put(nskb, padlen); 52 memset(pad, 0, padlen); 53 } 54 55 trailer = skb_put(nskb, 4); 56 trailer[0] = 0x80; 57 trailer[1] = 1 << p->port; 58 trailer[2] = 0x10; 59 trailer[3] = 0x00; 60 61 nskb->protocol = htons(ETH_P_TRAILER); 62 63 nskb->dev = p->parent->dst->master_netdev; 64 dev_queue_xmit(nskb); 65 66 return NETDEV_TX_OK; 67 } 68 69 static int trailer_rcv(struct sk_buff *skb, struct net_device *dev, 70 struct packet_type *pt, struct net_device *orig_dev) 71 { 72 struct dsa_switch_tree *dst = dev->dsa_ptr; 73 struct dsa_switch *ds; 74 u8 *trailer; 75 int source_port; 76 77 if (unlikely(dst == NULL)) 78 goto out_drop; 79 ds = dst->ds[0]; 80 81 skb = skb_unshare(skb, GFP_ATOMIC); 82 if (skb == NULL) 83 goto out; 84 85 if (skb_linearize(skb)) 86 goto out_drop; 87 88 trailer = skb_tail_pointer(skb) - 4; 89 if (trailer[0] != 0x80 || (trailer[1] & 0xf8) != 0x00 || 90 (trailer[3] & 0xef) != 0x00 || trailer[3] != 0x00) 91 goto out_drop; 92 93 source_port = trailer[1] & 7; 94 if (source_port >= DSA_MAX_PORTS || ds->ports[source_port] == NULL) 95 goto out_drop; 96 97 pskb_trim_rcsum(skb, skb->len - 4); 98 99 skb->dev = ds->ports[source_port]; 100 skb_push(skb, ETH_HLEN); 101 skb->pkt_type = PACKET_HOST; 102 skb->protocol = eth_type_trans(skb, skb->dev); 103 104 skb->dev->stats.rx_packets++; 105 skb->dev->stats.rx_bytes += skb->len; 106 107 netif_receive_skb(skb); 108 109 return 0; 110 111 out_drop: 112 kfree_skb(skb); 113 out: 114 return 0; 115 } 116 117 static struct packet_type trailer_packet_type __read_mostly = { 118 .type = cpu_to_be16(ETH_P_TRAILER), 119 .func = trailer_rcv, 120 }; 121 122 static int __init trailer_init_module(void) 123 { 124 dev_add_pack(&trailer_packet_type); 125 return 0; 126 } 127 module_init(trailer_init_module); 128 129 static void __exit trailer_cleanup_module(void) 130 { 131 dev_remove_pack(&trailer_packet_type); 132 } 133 module_exit(trailer_cleanup_module); 134