xref: /openbmc/linux/net/ipv6/ila/ila_lwt.c (revision 4f205687)
1 #include <linux/errno.h>
2 #include <linux/ip.h>
3 #include <linux/kernel.h>
4 #include <linux/module.h>
5 #include <linux/skbuff.h>
6 #include <linux/socket.h>
7 #include <linux/types.h>
8 #include <net/checksum.h>
9 #include <net/ip.h>
10 #include <net/ip6_fib.h>
11 #include <net/lwtunnel.h>
12 #include <net/protocol.h>
13 #include <uapi/linux/ila.h>
14 #include "ila.h"
15 
16 static inline struct ila_params *ila_params_lwtunnel(
17 	struct lwtunnel_state *lwstate)
18 {
19 	return (struct ila_params *)lwstate->data;
20 }
21 
22 static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb)
23 {
24 	struct dst_entry *dst = skb_dst(skb);
25 
26 	if (skb->protocol != htons(ETH_P_IPV6))
27 		goto drop;
28 
29 	ila_update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate));
30 
31 	return dst->lwtstate->orig_output(net, sk, skb);
32 
33 drop:
34 	kfree_skb(skb);
35 	return -EINVAL;
36 }
37 
38 static int ila_input(struct sk_buff *skb)
39 {
40 	struct dst_entry *dst = skb_dst(skb);
41 
42 	if (skb->protocol != htons(ETH_P_IPV6))
43 		goto drop;
44 
45 	ila_update_ipv6_locator(skb, ila_params_lwtunnel(dst->lwtstate));
46 
47 	return dst->lwtstate->orig_input(skb);
48 
49 drop:
50 	kfree_skb(skb);
51 	return -EINVAL;
52 }
53 
54 static struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
55 	[ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
56 	[ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
57 };
58 
59 static int ila_build_state(struct net_device *dev, struct nlattr *nla,
60 			   unsigned int family, const void *cfg,
61 			   struct lwtunnel_state **ts)
62 {
63 	struct ila_params *p;
64 	struct nlattr *tb[ILA_ATTR_MAX + 1];
65 	size_t encap_len = sizeof(*p);
66 	struct lwtunnel_state *newts;
67 	const struct fib6_config *cfg6 = cfg;
68 	struct ila_addr *iaddr;
69 	int ret;
70 
71 	if (family != AF_INET6)
72 		return -EINVAL;
73 
74 	if (cfg6->fc_dst_len < sizeof(struct ila_locator) + 1) {
75 		/* Need to have full locator and at least type field
76 		 * included in destination
77 		 */
78 		return -EINVAL;
79 	}
80 
81 	iaddr = (struct ila_addr *)&cfg6->fc_dst;
82 
83 	if (!ila_addr_is_ila(iaddr) || ila_csum_neutral_set(iaddr->ident)) {
84 		/* Don't allow translation for a non-ILA address or checksum
85 		 * neutral flag to be set.
86 		 */
87 		return -EINVAL;
88 	}
89 
90 	ret = nla_parse_nested(tb, ILA_ATTR_MAX, nla,
91 			       ila_nl_policy);
92 	if (ret < 0)
93 		return ret;
94 
95 	if (!tb[ILA_ATTR_LOCATOR])
96 		return -EINVAL;
97 
98 	newts = lwtunnel_state_alloc(encap_len);
99 	if (!newts)
100 		return -ENOMEM;
101 
102 	newts->len = encap_len;
103 	p = ila_params_lwtunnel(newts);
104 
105 	p->locator.v64 = (__force __be64)nla_get_u64(tb[ILA_ATTR_LOCATOR]);
106 
107 	/* Precompute checksum difference for translation since we
108 	 * know both the old locator and the new one.
109 	 */
110 	p->locator_match = iaddr->loc;
111 	p->csum_diff = compute_csum_diff8(
112 		(__be32 *)&p->locator_match, (__be32 *)&p->locator);
113 
114 	if (tb[ILA_ATTR_CSUM_MODE])
115 		p->csum_mode = nla_get_u8(tb[ILA_ATTR_CSUM_MODE]);
116 
117 	ila_init_saved_csum(p);
118 
119 	newts->type = LWTUNNEL_ENCAP_ILA;
120 	newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
121 			LWTUNNEL_STATE_INPUT_REDIRECT;
122 
123 	*ts = newts;
124 
125 	return 0;
126 }
127 
128 static int ila_fill_encap_info(struct sk_buff *skb,
129 			       struct lwtunnel_state *lwtstate)
130 {
131 	struct ila_params *p = ila_params_lwtunnel(lwtstate);
132 
133 	if (nla_put_u64_64bit(skb, ILA_ATTR_LOCATOR, (__force u64)p->locator.v64,
134 			      ILA_ATTR_PAD))
135 		goto nla_put_failure;
136 	if (nla_put_u8(skb, ILA_ATTR_CSUM_MODE, (__force u8)p->csum_mode))
137 		goto nla_put_failure;
138 
139 	return 0;
140 
141 nla_put_failure:
142 	return -EMSGSIZE;
143 }
144 
145 static int ila_encap_nlsize(struct lwtunnel_state *lwtstate)
146 {
147 	return nla_total_size_64bit(sizeof(u64)) + /* ILA_ATTR_LOCATOR */
148 	       nla_total_size(sizeof(u8)) +        /* ILA_ATTR_CSUM_MODE */
149 	       0;
150 }
151 
152 static int ila_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
153 {
154 	struct ila_params *a_p = ila_params_lwtunnel(a);
155 	struct ila_params *b_p = ila_params_lwtunnel(b);
156 
157 	return (a_p->locator.v64 != b_p->locator.v64);
158 }
159 
160 static const struct lwtunnel_encap_ops ila_encap_ops = {
161 	.build_state = ila_build_state,
162 	.output = ila_output,
163 	.input = ila_input,
164 	.fill_encap = ila_fill_encap_info,
165 	.get_encap_size = ila_encap_nlsize,
166 	.cmp_encap = ila_encap_cmp,
167 };
168 
169 int ila_lwt_init(void)
170 {
171 	return lwtunnel_encap_add_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
172 }
173 
174 void ila_lwt_fini(void)
175 {
176 	lwtunnel_encap_del_ops(&ila_encap_ops, LWTUNNEL_ENCAP_ILA);
177 }
178