1#include <net/ip.h>
 2#include <net/udp.h>
 3#include <net/udplite.h>
 4#include <asm/checksum.h>
 5
 6#ifndef _HAVE_ARCH_IPV6_CSUM
 7__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 8			const struct in6_addr *daddr,
 9			__u32 len, unsigned short proto,
10			__wsum csum)
11{
12
13	int carry;
14	__u32 ulen;
15	__u32 uproto;
16	__u32 sum = (__force u32)csum;
17
18	sum += (__force u32)saddr->s6_addr32[0];
19	carry = (sum < (__force u32)saddr->s6_addr32[0]);
20	sum += carry;
21
22	sum += (__force u32)saddr->s6_addr32[1];
23	carry = (sum < (__force u32)saddr->s6_addr32[1]);
24	sum += carry;
25
26	sum += (__force u32)saddr->s6_addr32[2];
27	carry = (sum < (__force u32)saddr->s6_addr32[2]);
28	sum += carry;
29
30	sum += (__force u32)saddr->s6_addr32[3];
31	carry = (sum < (__force u32)saddr->s6_addr32[3]);
32	sum += carry;
33
34	sum += (__force u32)daddr->s6_addr32[0];
35	carry = (sum < (__force u32)daddr->s6_addr32[0]);
36	sum += carry;
37
38	sum += (__force u32)daddr->s6_addr32[1];
39	carry = (sum < (__force u32)daddr->s6_addr32[1]);
40	sum += carry;
41
42	sum += (__force u32)daddr->s6_addr32[2];
43	carry = (sum < (__force u32)daddr->s6_addr32[2]);
44	sum += carry;
45
46	sum += (__force u32)daddr->s6_addr32[3];
47	carry = (sum < (__force u32)daddr->s6_addr32[3]);
48	sum += carry;
49
50	ulen = (__force u32)htonl((__u32) len);
51	sum += ulen;
52	carry = (sum < ulen);
53	sum += carry;
54
55	uproto = (__force u32)htonl(proto);
56	sum += uproto;
57	carry = (sum < uproto);
58	sum += carry;
59
60	return csum_fold((__force __wsum)sum);
61}
62EXPORT_SYMBOL(csum_ipv6_magic);
63#endif
64
65int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
66{
67	int err;
68
69	UDP_SKB_CB(skb)->partial_cov = 0;
70	UDP_SKB_CB(skb)->cscov = skb->len;
71
72	if (proto == IPPROTO_UDPLITE) {
73		err = udplite_checksum_init(skb, uh);
74		if (err)
75			return err;
76	}
77
78	if (uh->check == 0) {
79		/* RFC 2460 section 8.1 says that we SHOULD log
80		   this error. Well, it is reasonable.
81		 */
82		LIMIT_NETDEBUG(KERN_INFO "IPv6: udp checksum is 0 for [%pI6c]:%u->[%pI6c]:%u\n",
83			       &ipv6_hdr(skb)->saddr, ntohs(uh->source),
84			       &ipv6_hdr(skb)->daddr, ntohs(uh->dest));
85		return 1;
86	}
87	if (skb->ip_summed == CHECKSUM_COMPLETE &&
88	    !csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
89			     skb->len, proto, skb->csum))
90		skb->ip_summed = CHECKSUM_UNNECESSARY;
91
92	if (!skb_csum_unnecessary(skb))
93		skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
94							 &ipv6_hdr(skb)->daddr,
95							 skb->len, proto, 0));
96
97	return 0;
98}
99EXPORT_SYMBOL(udp6_csum_init);