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