net/8021q/vlan_core.c

   1 #include <linux/skbuff.h>
   2 #include <linux/netdevice.h>
   3 #include <linux/if_vlan.h>
   4 #include <linux/netpoll.h>
   5 #include <linux/export.h>
   6 #include "vlan.h"
   7
   8 bool vlan_do_receive(struct sk_buff **skbp, bool last_handler)
   9 {
  10         struct sk_buff *skb = *skbp;
  11         u16 vlan_id = skb->vlan_tci & VLAN_VID_MASK;
  12         struct net_device *vlan_dev;
  13         struct vlan_pcpu_stats *rx_stats;
  14
  15         vlan_dev = vlan_find_dev(skb->dev, vlan_id);
  16         if (!vlan_dev) {
  17                 /* Only the last call to vlan_do_receive() should change
  18                  * pkt_type to PACKET_OTHERHOST
  19                  */
  20                 if (vlan_id && last_handler)
  21                         skb->pkt_type = PACKET_OTHERHOST;
  22                 return false;
  23         }
  24
  25         skb = *skbp = skb_share_check(skb, GFP_ATOMIC);
  26         if (unlikely(!skb))
  27                 return false;
  28
  29         skb->dev = vlan_dev;
  30         if (skb->pkt_type == PACKET_OTHERHOST) {
  31                 /* Our lower layer thinks this is not local, let's make sure.
  32                  * This allows the VLAN to have a different MAC than the
  33                  * underlying device, and still route correctly. */
  34                 if (!compare_ether_addr(eth_hdr(skb)->h_dest,
  35                                         vlan_dev->dev_addr))
  36                         skb->pkt_type = PACKET_HOST;
  37         }
  38
  39         if (!(vlan_dev_info(vlan_dev)->flags & VLAN_FLAG_REORDER_HDR)) {
  40                 unsigned int offset = skb->data - skb_mac_header(skb);
  41
  42                 /*
  43                  * vlan_insert_tag expect skb->data pointing to mac header.
  44                  * So change skb->data before calling it and change back to
  45                  * original position later
  46                  */
  47                 skb_push(skb, offset);
  48                 skb = *skbp = vlan_insert_tag(skb, skb->vlan_tci);
  49                 if (!skb)
  50                         return false;
  51                 skb_pull(skb, offset + VLAN_HLEN);
  52                 skb_reset_mac_len(skb);
  53         }
  54
  55         skb->priority = vlan_get_ingress_priority(vlan_dev, skb->vlan_tci);
  56         skb->vlan_tci = 0;
  57
  58         rx_stats = this_cpu_ptr(vlan_dev_info(vlan_dev)->vlan_pcpu_stats);
  59
  60         u64_stats_update_begin(&rx_stats->syncp);
  61         rx_stats->rx_packets++;
  62         rx_stats->rx_bytes += skb->len;
  63         if (skb->pkt_type == PACKET_MULTICAST)
  64                 rx_stats->rx_multicast++;
  65         u64_stats_update_end(&rx_stats->syncp);
  66
  67         return true;
  68 }
  69
  70 /* Must be invoked with rcu_read_lock or with RTNL. */
  71 struct net_device *__vlan_find_dev_deep(struct net_device *real_dev,
  72                                         u16 vlan_id)
  73 {
  74         struct vlan_group *grp = rcu_dereference_rtnl(real_dev->vlgrp);
  75
  76         if (grp) {
  77                 return vlan_group_get_device(grp, vlan_id);
  78         } else {
  79                 /*
  80                  * Bonding slaves do not have grp assigned to themselves.
  81                  * Grp is assigned to bonding master instead.
  82                  */
  83                 if (netif_is_bond_slave(real_dev))
  84                         return __vlan_find_dev_deep(real_dev->master, vlan_id);
  85         }
  86
  87         return NULL;
  88 }
  89 EXPORT_SYMBOL(__vlan_find_dev_deep);
  90
  91 struct net_device *vlan_dev_real_dev(const struct net_device *dev)
  92 {
  93         return vlan_dev_info(dev)->real_dev;
  94 }
  95 EXPORT_SYMBOL(vlan_dev_real_dev);
  96
  97 u16 vlan_dev_vlan_id(const struct net_device *dev)
  98 {
  99         return vlan_dev_info(dev)->vlan_id;
 100 }
 101 EXPORT_SYMBOL(vlan_dev_vlan_id);
 102
 103 static struct sk_buff *vlan_reorder_header(struct sk_buff *skb)
 104 {
 105         if (skb_cow(skb, skb_headroom(skb)) < 0)
 106                 return NULL;
 107         memmove(skb->data - ETH_HLEN, skb->data - VLAN_ETH_HLEN, 2 * ETH_ALEN);
 108         skb->mac_header += VLAN_HLEN;
 109         skb_reset_mac_len(skb);
 110         return skb;
 111 }
 112
 113 static void vlan_set_encap_proto(struct sk_buff *skb, struct vlan_hdr *vhdr)
 114 {
 115         __be16 proto;
 116         unsigned char *rawp;
 117
 118         /*
 119          * Was a VLAN packet, grab the encapsulated protocol, which the layer
 120          * three protocols care about.
 121          */
 122
 123         proto = vhdr->h_vlan_encapsulated_proto;
 124         if (ntohs(proto) >= 1536) {
 125                 skb->protocol = proto;
 126                 return;
 127         }
 128
 129         rawp = skb->data;
 130         if (*(unsigned short *) rawp == 0xFFFF)
 131                 /*
 132                  * This is a magic hack to spot IPX packets. Older Novell
 133                  * breaks the protocol design and runs IPX over 802.3 without
 134                  * an 802.2 LLC layer. We look for FFFF which isn't a used
 135                  * 802.2 SSAP/DSAP. This won't work for fault tolerant netware
 136                  * but does for the rest.
 137                  */
 138                 skb->protocol = htons(ETH_P_802_3);
 139         else
 140                 /*
 141                  * Real 802.2 LLC
 142                  */
 143                 skb->protocol = htons(ETH_P_802_2);
 144 }
 145
 146 struct sk_buff *vlan_untag(struct sk_buff *skb)
 147 {
 148         struct vlan_hdr *vhdr;
 149         u16 vlan_tci;
 150
 151         if (unlikely(vlan_tx_tag_present(skb))) {
 152                 /* vlan_tci is already set-up so leave this for another time */
 153                 return skb;
 154         }
 155
 156         skb = skb_share_check(skb, GFP_ATOMIC);
 157         if (unlikely(!skb))
 158                 goto err_free;
 159
 160         if (unlikely(!pskb_may_pull(skb, VLAN_HLEN)))
 161                 goto err_free;
 162
 163         vhdr = (struct vlan_hdr *) skb->data;
 164         vlan_tci = ntohs(vhdr->h_vlan_TCI);
 165         __vlan_hwaccel_put_tag(skb, vlan_tci);
 166
 167         skb_pull_rcsum(skb, VLAN_HLEN);
 168         vlan_set_encap_proto(skb, vhdr);
 169
 170         skb = vlan_reorder_header(skb);
 171         if (unlikely(!skb))
 172                 goto err_free;
 173
 174         skb_reset_network_header(skb);
 175         skb_reset_transport_header(skb);
 176         return skb;
 177
 178 err_free:
 179         kfree_skb(skb);
 180         return NULL;
 181 }