xref: /openbmc/linux/net/mpls/internal.h (revision 9b9c2cd4)
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 */
134