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 void ila_init_saved_csum(struct ila_params *p)
17 {
18 if (!p->locator_match.v64)
19 return;
20
21 p->csum_diff = compute_csum_diff8(
22 (__be32 *)&p->locator,
23 (__be32 *)&p->locator_match);
24 }
25
26 static __wsum get_csum_diff_iaddr(struct ila_addr *iaddr, struct ila_params *p)
27 {
28 if (p->locator_match.v64)
29 return p->csum_diff;
30 else
31 return compute_csum_diff8((__be32 *)&p->locator,
32 (__be32 *)&iaddr->loc);
33 }
34
35 static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
36 {
37 return get_csum_diff_iaddr(ila_a2i(&ip6h->daddr), p);
38 }
39
40 static void ila_csum_do_neutral_fmt(struct ila_addr *iaddr,
41 struct ila_params *p)
42 {
43 __sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
44 __wsum diff, fval;
45
46 diff = get_csum_diff_iaddr(iaddr, p);
47
48 fval = (__force __wsum)(ila_csum_neutral_set(iaddr->ident) ?
49 CSUM_NEUTRAL_FLAG : ~CSUM_NEUTRAL_FLAG);
50
51 diff = csum_add(diff, fval);
52
53 *adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust)));
54
55 /* Flip the csum-neutral bit. Either we are doing a SIR->ILA
56 * translation with ILA_CSUM_NEUTRAL_MAP as the csum_method
57 * and the C-bit is not set, or we are doing an ILA-SIR
58 * tranlsation and the C-bit is set.
59 */
60 iaddr->ident.csum_neutral ^= 1;
61 }
62
63 static void ila_csum_do_neutral_nofmt(struct ila_addr *iaddr,
64 struct ila_params *p)
65 {
66 __sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
67 __wsum diff;
68
69 diff = get_csum_diff_iaddr(iaddr, p);
70
71 *adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust)));
72 }
73
74 static void ila_csum_adjust_transport(struct sk_buff *skb,
75 struct ila_params *p)
76 {
77 size_t nhoff = sizeof(struct ipv6hdr);
78 struct ipv6hdr *ip6h = ipv6_hdr(skb);
79 __wsum diff;
80
81 switch (ip6h->nexthdr) {
82 case NEXTHDR_TCP:
83 if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) {
84 struct tcphdr *th = (struct tcphdr *)
85 (skb_network_header(skb) + nhoff);
86
87 diff = get_csum_diff(ip6h, p);
88 inet_proto_csum_replace_by_diff(&th->check, skb,
89 diff, true);
90 }
91 break;
92 case NEXTHDR_UDP:
93 if (likely(pskb_may_pull(skb, nhoff + sizeof(struct udphdr)))) {
94 struct udphdr *uh = (struct udphdr *)
95 (skb_network_header(skb) + nhoff);
96
97 if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
98 diff = get_csum_diff(ip6h, p);
99 inet_proto_csum_replace_by_diff(&uh->check, skb,
100 diff, true);
101 if (!uh->check)
102 uh->check = CSUM_MANGLED_0;
103 }
104 }
105 break;
106 case NEXTHDR_ICMP:
107 if (likely(pskb_may_pull(skb,
108 nhoff + sizeof(struct icmp6hdr)))) {
109 struct icmp6hdr *ih = (struct icmp6hdr *)
110 (skb_network_header(skb) + nhoff);
111
112 diff = get_csum_diff(ip6h, p);
113 inet_proto_csum_replace_by_diff(&ih->icmp6_cksum, skb,
114 diff, true);
115 }
116 break;
117 }
118 }
119
120 void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p,
121 bool sir2ila)
122 {
123 struct ipv6hdr *ip6h = ipv6_hdr(skb);
124 struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
125
126 switch (p->csum_mode) {
127 case ILA_CSUM_ADJUST_TRANSPORT:
128 ila_csum_adjust_transport(skb, p);
129 break;
130 case ILA_CSUM_NEUTRAL_MAP:
131 if (sir2ila) {
132 if (WARN_ON(ila_csum_neutral_set(iaddr->ident))) {
133 /* Checksum flag should never be
134 * set in a formatted SIR address.
135 */
136 break;
137 }
138 } else if (!ila_csum_neutral_set(iaddr->ident)) {
139 /* ILA to SIR translation and C-bit isn't
140 * set so we're good.
141 */
142 break;
143 }
144 ila_csum_do_neutral_fmt(iaddr, p);
145 break;
146 case ILA_CSUM_NEUTRAL_MAP_AUTO:
147 ila_csum_do_neutral_nofmt(iaddr, p);
148 break;
149 case ILA_CSUM_NO_ACTION:
150 break;
151 }
152
153 /* Now change destination address */
154 iaddr->loc = p->locator;
155 }
156
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