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