blob: 72d198b8e4d2966d81fc5c183b12333e49e56d3f [file] [log] [blame]
Cong Wangacb3e042013-01-07 20:52:40 +00001#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\n");
83 return 1;
84 }
85 if (skb->ip_summed == CHECKSUM_COMPLETE &&
86 !csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
87 skb->len, proto, skb->csum))
88 skb->ip_summed = CHECKSUM_UNNECESSARY;
89
90 if (!skb_csum_unnecessary(skb))
91 skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
92 &ipv6_hdr(skb)->daddr,
93 skb->len, proto, 0));
94
95 return 0;
96}
97EXPORT_SYMBOL(udp6_csum_init);