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gerrit-public.fairphone.software / kernel / msm-4.9 / 5cf896b3c7842036ba37cc7057d74d5a2af159a7 / . / net / ipv6 / ip6_checksum.c
blob: 9a4d7322fb22234c5d697c384a74949beb2e50c5 [file] [log] [blame]
Cong Wangacb3e042013-01-07 20:52:40 +0000[diff] [blame]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
Tom Herbert40685792014-05-02 16:29:58 -0700[diff] [blame]78 /* To support RFC 6936 (allow zero checksum in UDP/IPV6 for tunnels)
79 * we accept a checksum of zero here. When we find the socket
80 * for the UDP packet we'll check if that socket allows zero checksum
81 * for IPv6 (set by socket option).
82 */
83 return skb_checksum_init_zero_check(skb, proto, uh->check,
84 ip6_compute_pseudo);
Cong Wangacb3e042013-01-07 20:52:40 +0000[diff] [blame]85}
86EXPORT_SYMBOL(udp6_csum_init);
Tom Herbertaf5fcba2014-06-04 17:19:48 -0700[diff] [blame]87
88/* Function to set UDP checksum for an IPv6 UDP packet. This is intended
89 * for the simple case like when setting the checksum for a UDP tunnel.
90 */
91void udp6_set_csum(bool nocheck, struct sk_buff *skb,
92 const struct in6_addr *saddr,
93 const struct in6_addr *daddr, int len)
94{
95 struct udphdr *uh = udp_hdr(skb);
96
97 if (nocheck)
98 uh->check = 0;
99 else if (skb_is_gso(skb))
100 uh->check = ~udp_v6_check(len, saddr, daddr, 0);
101 else if (skb_dst(skb) && skb_dst(skb)->dev &&
102 (skb_dst(skb)->dev->features & NETIF_F_IPV6_CSUM)) {
103
104 BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL);
105
106 skb->ip_summed = CHECKSUM_PARTIAL;
107 skb->csum_start = skb_transport_header(skb) - skb->head;
108 skb->csum_offset = offsetof(struct udphdr, check);
109 uh->check = ~udp_v6_check(len, saddr, daddr, 0);
110 } else {
111 __wsum csum;
112
113 BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL);
114
115 uh->check = 0;
116 csum = skb_checksum(skb, 0, len, 0);
117 uh->check = udp_v6_check(len, saddr, daddr, csum);
118 if (uh->check == 0)
119 uh->check = CSUM_MANGLED_0;
120
121 skb->ip_summed = CHECKSUM_UNNECESSARY;
122 }
123}
124EXPORT_SYMBOL(udp6_set_csum);