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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
ba4e58ec GR |
2 | /* |
3 | * Definitions for the UDP-Lite (RFC 3828) code. | |
4 | */ | |
5 | #ifndef _UDPLITE_H | |
6 | #define _UDPLITE_H | |
7 | ||
6bb100b9 DM |
8 | #include <net/ip6_checksum.h> |
9 | ||
ba4e58ec GR |
10 | /* UDP-Lite socket options */ |
11 | #define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */ | |
12 | #define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */ | |
13 | ||
14 | extern struct proto udplite_prot; | |
645ca708 | 15 | extern struct udp_table udplite_table; |
ba4e58ec | 16 | |
ba4e58ec GR |
17 | /* |
18 | * Checksum computation is all in software, hence simpler getfrag. | |
19 | */ | |
20 | static __inline__ int udplite_getfrag(void *from, char *to, int offset, | |
21 | int len, int odd, struct sk_buff *skb) | |
22 | { | |
f69e6d13 | 23 | struct msghdr *msg = from; |
0b62fca2 | 24 | return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT; |
ba4e58ec GR |
25 | } |
26 | ||
27 | /* Designate sk as UDP-Lite socket */ | |
28 | static inline int udplite_sk_init(struct sock *sk) | |
29 | { | |
2276f58a | 30 | udp_init_sock(sk); |
ba4e58ec GR |
31 | udp_sk(sk)->pcflag = UDPLITE_BIT; |
32 | return 0; | |
33 | } | |
34 | ||
35 | /* | |
36 | * Checksumming routines | |
37 | */ | |
38 | static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh) | |
39 | { | |
40 | u16 cscov; | |
41 | ||
42 | /* In UDPv4 a zero checksum means that the transmitter generated no | |
43 | * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets | |
44 | * with a zero checksum field are illegal. */ | |
45 | if (uh->check == 0) { | |
ba7a46f1 | 46 | net_dbg_ratelimited("UDPLite: zeroed checksum field\n"); |
ba4e58ec GR |
47 | return 1; |
48 | } | |
49 | ||
ba4e58ec GR |
50 | cscov = ntohs(uh->len); |
51 | ||
52 | if (cscov == 0) /* Indicates that full coverage is required. */ | |
759e5d00 | 53 | ; |
ba4e58ec GR |
54 | else if (cscov < 8 || cscov > skb->len) { |
55 | /* | |
56 | * Coverage length violates RFC 3828: log and discard silently. | |
57 | */ | |
ba7a46f1 JP |
58 | net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n", |
59 | cscov, skb->len); | |
ba4e58ec GR |
60 | return 1; |
61 | ||
759e5d00 | 62 | } else if (cscov < skb->len) { |
ba4e58ec | 63 | UDP_SKB_CB(skb)->partial_cov = 1; |
759e5d00 HX |
64 | UDP_SKB_CB(skb)->cscov = cscov; |
65 | if (skb->ip_summed == CHECKSUM_COMPLETE) | |
66 | skb->ip_summed = CHECKSUM_NONE; | |
67 | } | |
ba4e58ec GR |
68 | |
69 | return 0; | |
70 | } | |
71 | ||
f36c23bb GR |
72 | /* Slow-path computation of checksum. Socket is locked. */ |
73 | static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb) | |
ba4e58ec | 74 | { |
f36c23bb | 75 | const struct udp_sock *up = udp_sk(skb->sk); |
ba4e58ec | 76 | int cscov = up->len; |
f36c23bb | 77 | __wsum csum = 0; |
ba4e58ec | 78 | |
f36c23bb GR |
79 | if (up->pcflag & UDPLITE_SEND_CC) { |
80 | /* | |
81 | * Sender has set `partial coverage' option on UDP-Lite socket. | |
82 | * The special case "up->pcslen == 0" signifies full coverage. | |
83 | */ | |
ba4e58ec | 84 | if (up->pcslen < up->len) { |
f36c23bb GR |
85 | if (0 < up->pcslen) |
86 | cscov = up->pcslen; | |
87 | udp_hdr(skb)->len = htons(up->pcslen); | |
ba4e58ec | 88 | } |
f36c23bb GR |
89 | /* |
90 | * NOTE: Causes for the error case `up->pcslen > up->len': | |
91 | * (i) Application error (will not be penalized). | |
92 | * (ii) Payload too big for send buffer: data is split | |
93 | * into several packets, each with its own header. | |
94 | * In this case (e.g. last segment), coverage may | |
95 | * exceed packet length. | |
96 | * Since packets with coverage length > packet length are | |
97 | * illegal, we fall back to the defaults here. | |
98 | */ | |
ba4e58ec | 99 | } |
ba4e58ec GR |
100 | |
101 | skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */ | |
102 | ||
103 | skb_queue_walk(&sk->sk_write_queue, skb) { | |
ea2ae17d ACM |
104 | const int off = skb_transport_offset(skb); |
105 | const int len = skb->len - off; | |
ba4e58ec GR |
106 | |
107 | csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum); | |
108 | ||
109 | if ((cscov -= len) <= 0) | |
110 | break; | |
111 | } | |
112 | return csum; | |
113 | } | |
114 | ||
f36c23bb | 115 | /* Fast-path computation of checksum. Socket may not be locked. */ |
f6b9664f HX |
116 | static inline __wsum udplite_csum(struct sk_buff *skb) |
117 | { | |
f36c23bb | 118 | const struct udp_sock *up = udp_sk(skb->sk); |
f6b9664f | 119 | const int off = skb_transport_offset(skb); |
f36c23bb | 120 | int len = skb->len - off; |
f6b9664f | 121 | |
f36c23bb GR |
122 | if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) { |
123 | if (0 < up->pcslen) | |
124 | len = up->pcslen; | |
125 | udp_hdr(skb)->len = htons(up->pcslen); | |
126 | } | |
f6b9664f HX |
127 | skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */ |
128 | ||
f36c23bb | 129 | return skb_checksum(skb, off, len, 0); |
f6b9664f HX |
130 | } |
131 | ||
16073439 JP |
132 | void udplite4_register(void); |
133 | int udplite_get_port(struct sock *sk, unsigned short snum, | |
134 | int (*scmp)(const struct sock *, const struct sock *)); | |
ba4e58ec | 135 | #endif /* _UDPLITE_H */ |