1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/errno.h>
3 #include <linux/ip.h>
4 #include <linux/kernel.h>
5 #include <linux/module.h>
6 #include <linux/skbuff.h>
7 #include <linux/socket.h>
8 #include <linux/types.h>
9 #include <net/checksum.h>
10 #include <net/ip.h>
11 #include <net/ip6_fib.h>
12 #include <net/lwtunnel.h>
13 #include <net/protocol.h>
14 #include <uapi/linux/ila.h>
15 #include "ila.h"
16
ila_init_saved_csum(struct ila_params * p)17 void ila_init_saved_csum(struct ila_params *p)
18 {
19 if (!p->locator_match.v64)
20 return;
21
22 p->csum_diff = compute_csum_diff8(
23 (__be32 *)&p->locator,
24 (__be32 *)&p->locator_match);
25 }
26
get_csum_diff_iaddr(struct ila_addr * iaddr,struct ila_params * p)27 static __wsum get_csum_diff_iaddr(struct ila_addr *iaddr, struct ila_params *p)
28 {
29 if (p->locator_match.v64)
30 return p->csum_diff;
31 else
32 return compute_csum_diff8((__be32 *)&p->locator,
33 (__be32 *)&iaddr->loc);
34 }
35
get_csum_diff(struct ipv6hdr * ip6h,struct ila_params * p)36 static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
37 {
38 return get_csum_diff_iaddr(ila_a2i(&ip6h->daddr), p);
39 }
40
ila_csum_do_neutral_fmt(struct ila_addr * iaddr,struct ila_params * p)41 static void ila_csum_do_neutral_fmt(struct ila_addr *iaddr,
42 struct ila_params *p)
43 {
44 __sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
45 __wsum diff, fval;
46
47 diff = get_csum_diff_iaddr(iaddr, p);
48
49 fval = (__force __wsum)(ila_csum_neutral_set(iaddr->ident) ?
50 CSUM_NEUTRAL_FLAG : ~CSUM_NEUTRAL_FLAG);
51
52 diff = csum_add(diff, fval);
53
54 *adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust)));
55
56 /* Flip the csum-neutral bit. Either we are doing a SIR->ILA
57 * translation with ILA_CSUM_NEUTRAL_MAP as the csum_method
58 * and the C-bit is not set, or we are doing an ILA-SIR
59 * tranlsation and the C-bit is set.
60 */
61 iaddr->ident.csum_neutral ^= 1;
62 }
63
ila_csum_do_neutral_nofmt(struct ila_addr * iaddr,struct ila_params * p)64 static void ila_csum_do_neutral_nofmt(struct ila_addr *iaddr,
65 struct ila_params *p)
66 {
67 __sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
68 __wsum diff;
69
70 diff = get_csum_diff_iaddr(iaddr, p);
71
72 *adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust)));
73 }
74
ila_csum_adjust_transport(struct sk_buff * skb,struct ila_params * p)75 static void ila_csum_adjust_transport(struct sk_buff *skb,
76 struct ila_params *p)
77 {
78 size_t nhoff = sizeof(struct ipv6hdr);
79 struct ipv6hdr *ip6h = ipv6_hdr(skb);
80 __wsum diff;
81
82 switch (ip6h->nexthdr) {
83 case NEXTHDR_TCP:
84 if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) {
85 struct tcphdr *th = (struct tcphdr *)
86 (skb_network_header(skb) + nhoff);
87
88 ip6h = ipv6_hdr(skb);
89 diff = get_csum_diff(ip6h, p);
90 inet_proto_csum_replace_by_diff(&th->check, skb,
91 diff, true, true);
92 }
93 break;
94 case NEXTHDR_UDP:
95 if (likely(pskb_may_pull(skb, nhoff + sizeof(struct udphdr)))) {
96 struct udphdr *uh = (struct udphdr *)
97 (skb_network_header(skb) + nhoff);
98
99 if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
100 ip6h = ipv6_hdr(skb);
101 diff = get_csum_diff(ip6h, p);
102 inet_proto_csum_replace_by_diff(&uh->check, skb,
103 diff, true, true);
104 if (!uh->check)
105 uh->check = CSUM_MANGLED_0;
106 }
107 }
108 break;
109 case NEXTHDR_ICMP:
110 if (likely(pskb_may_pull(skb,
111 nhoff + sizeof(struct icmp6hdr)))) {
112 struct icmp6hdr *ih = (struct icmp6hdr *)
113 (skb_network_header(skb) + nhoff);
114
115 ip6h = ipv6_hdr(skb);
116 diff = get_csum_diff(ip6h, p);
117 inet_proto_csum_replace_by_diff(&ih->icmp6_cksum, skb,
118 diff, true, true);
119 }
120 break;
121 }
122 }
123
ila_update_ipv6_locator(struct sk_buff * skb,struct ila_params * p,bool sir2ila)124 void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p,
125 bool sir2ila)
126 {
127 struct ipv6hdr *ip6h = ipv6_hdr(skb);
128 struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
129
130 switch (p->csum_mode) {
131 case ILA_CSUM_ADJUST_TRANSPORT:
132 ila_csum_adjust_transport(skb, p);
133 /*
134 * ila_csum_adjust_transport() calls pskb_may_pull(), which can
135 * reallocate the skb head and leave ip6h (and the iaddr derived
136 * from it) dangling; reload both before the write below. The
137 * other csum modes do not pull, so their cached pointers stay
138 * valid.
139 */
140 ip6h = ipv6_hdr(skb);
141 iaddr = ila_a2i(&ip6h->daddr);
142 break;
143 case ILA_CSUM_NEUTRAL_MAP:
144 if (sir2ila) {
145 if (WARN_ON(ila_csum_neutral_set(iaddr->ident))) {
146 /* Checksum flag should never be
147 * set in a formatted SIR address.
148 */
149 break;
150 }
151 } else if (!ila_csum_neutral_set(iaddr->ident)) {
152 /* ILA to SIR translation and C-bit isn't
153 * set so we're good.
154 */
155 break;
156 }
157 ila_csum_do_neutral_fmt(iaddr, p);
158 break;
159 case ILA_CSUM_NEUTRAL_MAP_AUTO:
160 ila_csum_do_neutral_nofmt(iaddr, p);
161 break;
162 case ILA_CSUM_NO_ACTION:
163 break;
164 }
165
166 /* Now change destination address */
167 iaddr->loc = p->locator;
168 }
169