xref: /openbmc/linux/net/ipv6/ip6_checksum.c (revision 4068579e1e098fa81d48db9ba4432ab664c58561)
1acb3e041SCong Wang #include <net/ip.h>
2acb3e041SCong Wang #include <net/udp.h>
3acb3e041SCong Wang #include <net/udplite.h>
4acb3e041SCong Wang #include <asm/checksum.h>
5acb3e041SCong Wang 
6acb3e041SCong Wang #ifndef _HAVE_ARCH_IPV6_CSUM
7acb3e041SCong Wang __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
8acb3e041SCong Wang 			const struct in6_addr *daddr,
9acb3e041SCong Wang 			__u32 len, unsigned short proto,
10acb3e041SCong Wang 			__wsum csum)
11acb3e041SCong Wang {
12acb3e041SCong Wang 
13acb3e041SCong Wang 	int carry;
14acb3e041SCong Wang 	__u32 ulen;
15acb3e041SCong Wang 	__u32 uproto;
16acb3e041SCong Wang 	__u32 sum = (__force u32)csum;
17acb3e041SCong Wang 
18acb3e041SCong Wang 	sum += (__force u32)saddr->s6_addr32[0];
19acb3e041SCong Wang 	carry = (sum < (__force u32)saddr->s6_addr32[0]);
20acb3e041SCong Wang 	sum += carry;
21acb3e041SCong Wang 
22acb3e041SCong Wang 	sum += (__force u32)saddr->s6_addr32[1];
23acb3e041SCong Wang 	carry = (sum < (__force u32)saddr->s6_addr32[1]);
24acb3e041SCong Wang 	sum += carry;
25acb3e041SCong Wang 
26acb3e041SCong Wang 	sum += (__force u32)saddr->s6_addr32[2];
27acb3e041SCong Wang 	carry = (sum < (__force u32)saddr->s6_addr32[2]);
28acb3e041SCong Wang 	sum += carry;
29acb3e041SCong Wang 
30acb3e041SCong Wang 	sum += (__force u32)saddr->s6_addr32[3];
31acb3e041SCong Wang 	carry = (sum < (__force u32)saddr->s6_addr32[3]);
32acb3e041SCong Wang 	sum += carry;
33acb3e041SCong Wang 
34acb3e041SCong Wang 	sum += (__force u32)daddr->s6_addr32[0];
35acb3e041SCong Wang 	carry = (sum < (__force u32)daddr->s6_addr32[0]);
36acb3e041SCong Wang 	sum += carry;
37acb3e041SCong Wang 
38acb3e041SCong Wang 	sum += (__force u32)daddr->s6_addr32[1];
39acb3e041SCong Wang 	carry = (sum < (__force u32)daddr->s6_addr32[1]);
40acb3e041SCong Wang 	sum += carry;
41acb3e041SCong Wang 
42acb3e041SCong Wang 	sum += (__force u32)daddr->s6_addr32[2];
43acb3e041SCong Wang 	carry = (sum < (__force u32)daddr->s6_addr32[2]);
44acb3e041SCong Wang 	sum += carry;
45acb3e041SCong Wang 
46acb3e041SCong Wang 	sum += (__force u32)daddr->s6_addr32[3];
47acb3e041SCong Wang 	carry = (sum < (__force u32)daddr->s6_addr32[3]);
48acb3e041SCong Wang 	sum += carry;
49acb3e041SCong Wang 
50acb3e041SCong Wang 	ulen = (__force u32)htonl((__u32) len);
51acb3e041SCong Wang 	sum += ulen;
52acb3e041SCong Wang 	carry = (sum < ulen);
53acb3e041SCong Wang 	sum += carry;
54acb3e041SCong Wang 
55acb3e041SCong Wang 	uproto = (__force u32)htonl(proto);
56acb3e041SCong Wang 	sum += uproto;
57acb3e041SCong Wang 	carry = (sum < uproto);
58acb3e041SCong Wang 	sum += carry;
59acb3e041SCong Wang 
60acb3e041SCong Wang 	return csum_fold((__force __wsum)sum);
61acb3e041SCong Wang }
62acb3e041SCong Wang EXPORT_SYMBOL(csum_ipv6_magic);
63acb3e041SCong Wang #endif
64acb3e041SCong Wang 
65acb3e041SCong Wang int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
66acb3e041SCong Wang {
67acb3e041SCong Wang 	int err;
68acb3e041SCong Wang 
69acb3e041SCong Wang 	UDP_SKB_CB(skb)->partial_cov = 0;
70acb3e041SCong Wang 	UDP_SKB_CB(skb)->cscov = skb->len;
71acb3e041SCong Wang 
72acb3e041SCong Wang 	if (proto == IPPROTO_UDPLITE) {
73acb3e041SCong Wang 		err = udplite_checksum_init(skb, uh);
74acb3e041SCong Wang 		if (err)
75acb3e041SCong Wang 			return err;
76acb3e041SCong Wang 	}
77acb3e041SCong Wang 
78*4068579eSTom Herbert 	/* To support RFC 6936 (allow zero checksum in UDP/IPV6 for tunnels)
79*4068579eSTom Herbert 	 * we accept a checksum of zero here. When we find the socket
80*4068579eSTom Herbert 	 * for the UDP packet we'll check if that socket allows zero checksum
81*4068579eSTom Herbert 	 * for IPv6 (set by socket option).
82acb3e041SCong Wang 	 */
83*4068579eSTom Herbert 	return skb_checksum_init_zero_check(skb, proto, uh->check,
84*4068579eSTom Herbert 					   ip6_compute_pseudo);
85acb3e041SCong Wang }
86acb3e041SCong Wang EXPORT_SYMBOL(udp6_csum_init);
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