net/mpls/internal.h

   1 #ifndef MPLS_INTERNAL_H
   2 #define MPLS_INTERNAL_H
   3
   4 struct mpls_shim_hdr {
   5         __be32 label_stack_entry;
   6 };
   7
   8 struct mpls_entry_decoded {
   9         u32 label;
  10         u8 ttl;
  11         u8 tc;
  12         u8 bos;
  13 };
  14
  15 struct mpls_dev {
  16         int                     input_enabled;
  17
  18         struct ctl_table_header *sysctl;
  19         struct rcu_head         rcu;
  20 };
  21
  22 struct sk_buff;
  23
  24 #define LABEL_NOT_SPECIFIED (1 << 20)
  25 #define MAX_NEW_LABELS 2
  26
  27 /* This maximum ha length copied from the definition of struct neighbour */
  28 #define VIA_ALEN_ALIGN sizeof(unsigned long)
  29 #define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, VIA_ALEN_ALIGN))
  30
  31 enum mpls_payload_type {
  32         MPT_UNSPEC, /* IPv4 or IPv6 */
  33         MPT_IPV4 = 4,
  34         MPT_IPV6 = 6,
  35
  36         /* Other types not implemented:
  37          *  - Pseudo-wire with or without control word (RFC4385)
  38          *  - GAL (RFC5586)
  39          */
  40 };
  41
  42 struct mpls_nh { /* next hop label forwarding entry */
  43         struct net_device __rcu *nh_dev;
  44         u32                     nh_label[MAX_NEW_LABELS];
  45         u8                      nh_labels;
  46         u8                      nh_via_alen;
  47         u8                      nh_via_table;
  48 };
  49
  50 /* The route, nexthops and vias are stored together in the same memory
  51  * block:
  52  *
  53  * +----------------------+
  54  * | mpls_route           |
  55  * +----------------------+
  56  * | mpls_nh 0            |
  57  * +----------------------+
  58  * | ...                  |
  59  * +----------------------+
  60  * | mpls_nh n-1          |
  61  * +----------------------+
  62  * | alignment padding    |
  63  * +----------------------+
  64  * | via[rt_max_alen] 0   |
  65  * +----------------------+
  66  * | ...                  |
  67  * +----------------------+
  68  * | via[rt_max_alen] n-1 |
  69  * +----------------------+
  70  */
  71 struct mpls_route { /* next hop label forwarding entry */
  72         struct rcu_head         rt_rcu;
  73         u8                      rt_protocol;
  74         u8                      rt_payload_type;
  75         u8                      rt_max_alen;
  76         unsigned int            rt_nhn;
  77         struct mpls_nh          rt_nh[0];
  78 };
  79
  80 #define for_nexthops(rt) {                                              \
  81         int nhsel; struct mpls_nh *nh;                  \
  82         for (nhsel = 0, nh = (rt)->rt_nh;                               \
  83              nhsel < (rt)->rt_nhn;                                      \
  84              nh++, nhsel++)
  85
  86 #define change_nexthops(rt) {                                           \
  87         int nhsel; struct mpls_nh *nh;                          \
  88         for (nhsel = 0, nh = (struct mpls_nh *)((rt)->rt_nh);   \
  89              nhsel < (rt)->rt_nhn;                                      \
  90              nh++, nhsel++)
  91
  92 #define endfor_nexthops(rt) }
  93
  94 static inline struct mpls_shim_hdr *mpls_hdr(const struct sk_buff *skb)
  95 {
  96         return (struct mpls_shim_hdr *)skb_network_header(skb);
  97 }
  98
  99 static inline struct mpls_shim_hdr mpls_entry_encode(u32 label, unsigned ttl, unsigned tc, bool bos)
 100 {
 101         struct mpls_shim_hdr result;
 102         result.label_stack_entry =
 103                 cpu_to_be32((label << MPLS_LS_LABEL_SHIFT) |
 104                             (tc << MPLS_LS_TC_SHIFT) |
 105                             (bos ? (1 << MPLS_LS_S_SHIFT) : 0) |
 106                             (ttl << MPLS_LS_TTL_SHIFT));
 107         return result;
 108 }
 109
 110 static inline struct mpls_entry_decoded mpls_entry_decode(struct mpls_shim_hdr *hdr)
 111 {
 112         struct mpls_entry_decoded result;
 113         unsigned entry = be32_to_cpu(hdr->label_stack_entry);
 114
 115         result.label = (entry & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT;
 116         result.ttl = (entry & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT;
 117         result.tc =  (entry & MPLS_LS_TC_MASK) >> MPLS_LS_TC_SHIFT;
 118         result.bos = (entry & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT;
 119
 120         return result;
 121 }
 122
 123 int nla_put_labels(struct sk_buff *skb, int attrtype,  u8 labels,
 124                    const u32 label[]);
 125 int nla_get_labels(const struct nlattr *nla, u32 max_labels, u8 *labels,
 126                    u32 label[]);
 127 int nla_get_via(const struct nlattr *nla, u8 *via_alen, u8 *via_table,
 128                 u8 via[]);
 129 bool mpls_output_possible(const struct net_device *dev);
 130 unsigned int mpls_dev_mtu(const struct net_device *dev);
 131 bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu);
 132
 133 #endif /* MPLS_INTERNAL_H */