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
16void 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
26static __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
35static __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
40static 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
63static 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
74static 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
120void 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