1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <net/ip.h> |
3 | #include <net/udp.h> |
4 | #include <net/udplite.h> |
5 | #include <asm/checksum.h> |
6 | |
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) |
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 | } |
62 | EXPORT_SYMBOL(csum_ipv6_magic); |
63 | #endif |
64 | |
65 | int 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 | if (UDP_SKB_CB(skb)->partial_cov) { |
78 | skb->csum = ip6_compute_pseudo(skb, proto); |
79 | return 0; |
80 | } |
81 | } |
82 | |
83 | /* To support RFC 6936 (allow zero checksum in UDP/IPV6 for tunnels) |
84 | * we accept a checksum of zero here. When we find the socket |
85 | * for the UDP packet we'll check if that socket allows zero checksum |
86 | * for IPv6 (set by socket option). |
87 | * |
88 | * Note, we are only interested in != 0 or == 0, thus the |
89 | * force to int. |
90 | */ |
91 | err = (__force int)skb_checksum_init_zero_check(skb, proto, uh->check, |
92 | ip6_compute_pseudo); |
93 | if (err) |
94 | return err; |
95 | |
96 | if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) { |
97 | /* If SW calculated the value, we know it's bad */ |
98 | if (skb->csum_complete_sw) |
99 | return 1; |
100 | |
101 | /* HW says the value is bad. Let's validate that. |
102 | * skb->csum is no longer the full packet checksum, |
103 | * so don't treat is as such. |
104 | */ |
105 | skb_checksum_complete_unset(skb); |
106 | } |
107 | |
108 | return 0; |
109 | } |
110 | EXPORT_SYMBOL(udp6_csum_init); |
111 | |
112 | /* Function to set UDP checksum for an IPv6 UDP packet. This is intended |
113 | * for the simple case like when setting the checksum for a UDP tunnel. |
114 | */ |
115 | void udp6_set_csum(bool nocheck, struct sk_buff *skb, |
116 | const struct in6_addr *saddr, |
117 | const struct in6_addr *daddr, int len) |
118 | { |
119 | struct udphdr *uh = udp_hdr(skb); |
120 | |
121 | if (nocheck) |
122 | uh->check = 0; |
123 | else if (skb_is_gso(skb)) |
124 | uh->check = ~udp_v6_check(len, saddr, daddr, base: 0); |
125 | else if (skb->ip_summed == CHECKSUM_PARTIAL) { |
126 | uh->check = 0; |
127 | uh->check = udp_v6_check(len, saddr, daddr, base: lco_csum(skb)); |
128 | if (uh->check == 0) |
129 | uh->check = CSUM_MANGLED_0; |
130 | } else { |
131 | skb->ip_summed = CHECKSUM_PARTIAL; |
132 | skb->csum_start = skb_transport_header(skb) - skb->head; |
133 | skb->csum_offset = offsetof(struct udphdr, check); |
134 | uh->check = ~udp_v6_check(len, saddr, daddr, base: 0); |
135 | } |
136 | } |
137 | EXPORT_SYMBOL(udp6_set_csum); |
138 | |