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)
   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                 return false;
  18
  19         skb = *skbp = skb_share_check(skb, GFP_ATOMIC);
  20         if (unlikely(!skb))
  21                 return false;
  22
  23         skb->dev = vlan_dev;
  24         if (skb->pkt_type == PACKET_OTHERHOST) {
  25                 /* Our lower layer thinks this is not local, let's make sure.
  26                  * This allows the VLAN to have a different MAC than the
  27                  * underlying device, and still route correctly. */
  28                 if (!compare_ether_addr(eth_hdr(skb)->h_dest,
  29                                         vlan_dev->dev_addr))
  30                         skb->pkt_type = PACKET_HOST;
  31         }
  32
  33         if (!(vlan_dev_info(vlan_dev)->flags & VLAN_FLAG_REORDER_HDR)) {
  34                 unsigned int offset = skb->data - skb_mac_header(skb);
  35
  36                 /*
  37                  * vlan_insert_tag expect skb->data pointing to mac header.
  38                  * So change skb->data before calling it and change back to
  39                  * original position later
  40                  */
  41                 skb_push(skb, offset);
  42                 skb = *skbp = vlan_insert_tag(skb, skb->vlan_tci);
  43                 if (!skb)
  44                         return false;
  45                 skb_pull(skb, offset + VLAN_HLEN);
  46                 skb_reset_mac_len(skb);
  47         }
  48
  49         skb->priority = vlan_get_ingress_priority(vlan_dev, skb->vlan_tci);
  50         skb->vlan_tci = 0;
  51
  52         rx_stats = this_cpu_ptr(vlan_dev_info(vlan_dev)->vlan_pcpu_stats);
  53
  54         u64_stats_update_begin(&rx_stats->syncp);
  55         rx_stats->rx_packets++;
  56         rx_stats->rx_bytes += skb->len;
  57         if (skb->pkt_type == PACKET_MULTICAST)
  58                 rx_stats->rx_multicast++;
  59         u64_stats_update_end(&rx_stats->syncp);
  60
  61         return true;
  62 }
  63
  64 /* Must be invoked with rcu_read_lock or with RTNL. */
  65 struct net_device *__vlan_find_dev_deep(struct net_device *real_dev,
  66                                         u16 vlan_id)
  67 {
  68         struct vlan_group *grp = rcu_dereference_rtnl(real_dev->vlgrp);
  69
  70         if (grp) {
  71                 return vlan_group_get_device(grp, vlan_id);
  72         } else {
  73                 /*
  74                  * Bonding slaves do not have grp assigned to themselves.
  75                  * Grp is assigned to bonding master instead.
  76                  */
  77                 if (netif_is_bond_slave(real_dev))
  78                         return __vlan_find_dev_deep(real_dev->master, vlan_id);
  79         }
  80
  81         return NULL;
  82 }
  83 EXPORT_SYMBOL(__vlan_find_dev_deep);
  84
  85 struct net_device *vlan_dev_real_dev(const struct net_device *dev)
  86 {
  87         return vlan_dev_info(dev)->real_dev;
  88 }
  89 EXPORT_SYMBOL(vlan_dev_real_dev);
  90
  91 u16 vlan_dev_vlan_id(const struct net_device *dev)
  92 {
  93         return vlan_dev_info(dev)->vlan_id;
  94 }
  95 EXPORT_SYMBOL(vlan_dev_vlan_id);
  96
  97 static struct sk_buff *vlan_reorder_header(struct sk_buff *skb)
  98 {
  99         if (skb_cow(skb, skb_headroom(skb)) < 0) {
 100                 kfree_skb(skb);
 101                 return NULL;
 102         }
 103
 104         memmove(skb->data - ETH_HLEN, skb->data - VLAN_ETH_HLEN, 2 * ETH_ALEN);
 105         skb->mac_header += VLAN_HLEN;
 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         skb_reset_mac_len(skb);
 173
 174         return skb;
 175
 176 err_free:
 177         kfree_skb(skb);
 178         return NULL;
 179 }