1 // SPDX-License-Identifier: GPL-2.0
4 #include <net/udplite.h>
5 #include <asm/checksum.h>
7 #ifndef _HAVE_ARCH_IPV6_CSUM
8 __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
9 const struct in6_addr *daddr,
10 __u32 len, __u8 proto, __wsum csum)
16 __u32 sum = (__force u32)csum;
18 sum += (__force u32)saddr->s6_addr32[0];
19 carry = (sum < (__force u32)saddr->s6_addr32[0]);
22 sum += (__force u32)saddr->s6_addr32[1];
23 carry = (sum < (__force u32)saddr->s6_addr32[1]);
26 sum += (__force u32)saddr->s6_addr32[2];
27 carry = (sum < (__force u32)saddr->s6_addr32[2]);
30 sum += (__force u32)saddr->s6_addr32[3];
31 carry = (sum < (__force u32)saddr->s6_addr32[3]);
34 sum += (__force u32)daddr->s6_addr32[0];
35 carry = (sum < (__force u32)daddr->s6_addr32[0]);
38 sum += (__force u32)daddr->s6_addr32[1];
39 carry = (sum < (__force u32)daddr->s6_addr32[1]);
42 sum += (__force u32)daddr->s6_addr32[2];
43 carry = (sum < (__force u32)daddr->s6_addr32[2]);
46 sum += (__force u32)daddr->s6_addr32[3];
47 carry = (sum < (__force u32)daddr->s6_addr32[3]);
50 ulen = (__force u32)htonl((__u32) len);
55 uproto = (__force u32)htonl(proto);
57 carry = (sum < uproto);
60 return csum_fold((__force __wsum)sum);
62 EXPORT_SYMBOL(csum_ipv6_magic);
65 int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
69 UDP_SKB_CB(skb)->partial_cov = 0;
70 UDP_SKB_CB(skb)->cscov = skb->len;
72 if (proto == IPPROTO_UDPLITE) {
73 err = udplite_checksum_init(skb, uh);
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).
83 * Note, we are only interested in != 0 or == 0, thus the
86 return (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
89 EXPORT_SYMBOL(udp6_csum_init);
91 /* Function to set UDP checksum for an IPv6 UDP packet. This is intended
92 * for the simple case like when setting the checksum for a UDP tunnel.
94 void udp6_set_csum(bool nocheck, struct sk_buff *skb,
95 const struct in6_addr *saddr,
96 const struct in6_addr *daddr, int len)
98 struct udphdr *uh = udp_hdr(skb);
102 else if (skb_is_gso(skb))
103 uh->check = ~udp_v6_check(len, saddr, daddr, 0);
104 else if (skb->ip_summed == CHECKSUM_PARTIAL) {
106 uh->check = udp_v6_check(len, saddr, daddr, lco_csum(skb));
108 uh->check = CSUM_MANGLED_0;
110 skb->ip_summed = CHECKSUM_PARTIAL;
111 skb->csum_start = skb_transport_header(skb) - skb->head;
112 skb->csum_offset = offsetof(struct udphdr, check);
113 uh->check = ~udp_v6_check(len, saddr, daddr, 0);
116 EXPORT_SYMBOL(udp6_set_csum);