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	/* 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);
85}
86EXPORT_SYMBOL(udp6_csum_init);
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);
125