Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Definitions for the UDP-Lite (RFC 3828) code.
4 */
5#ifndef _UDPLITE_H
6#define _UDPLITE_H
7
8#include <net/ip6_checksum.h>
9#include <net/udp.h>
10
11/* UDP-Lite socket options */
12#define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */
13#define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */
14
15extern struct proto udplite_prot;
16extern struct udp_table udplite_table;
17
18/*
19 * Checksum computation is all in software, hence simpler getfrag.
20 */
21static __inline__ int udplite_getfrag(void *from, char *to, int offset,
22 int len, int odd, struct sk_buff *skb)
23{
24 struct msghdr *msg = from;
25 return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
26}
27
28/* Designate sk as UDP-Lite socket */
29static inline int udplite_sk_init(struct sock *sk)
30{
31 udp_init_sock(sk);
32 udp_sk(sk)->pcflag = UDPLITE_BIT;
33 return 0;
34}
35
36/*
37 * Checksumming routines
38 */
39static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
40{
41 u16 cscov;
42
43 /* In UDPv4 a zero checksum means that the transmitter generated no
44 * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
45 * with a zero checksum field are illegal. */
46 if (uh->check == 0) {
47 net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
48 return 1;
49 }
50
51 cscov = ntohs(uh->len);
52
53 if (cscov == 0) /* Indicates that full coverage is required. */
54 ;
55 else if (cscov < 8 || cscov > skb->len) {
56 /*
57 * Coverage length violates RFC 3828: log and discard silently.
58 */
59 net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
60 cscov, skb->len);
61 return 1;
62
63 } else if (cscov < skb->len) {
64 UDP_SKB_CB(skb)->partial_cov = 1;
65 UDP_SKB_CB(skb)->cscov = cscov;
66 if (skb->ip_summed == CHECKSUM_COMPLETE)
67 skb->ip_summed = CHECKSUM_NONE;
68 skb->csum_valid = 0;
69 }
70
71 return 0;
72}
73
74/* Fast-path computation of checksum. Socket may not be locked. */
75static inline __wsum udplite_csum(struct sk_buff *skb)
76{
77 const struct udp_sock *up = udp_sk(skb->sk);
78 const int off = skb_transport_offset(skb);
79 int len = skb->len - off;
80
81 if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
82 if (0 < up->pcslen)
83 len = up->pcslen;
84 udp_hdr(skb)->len = htons(up->pcslen);
85 }
86 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
87
88 return skb_checksum(skb, off, len, 0);
89}
90
91void udplite4_register(void);
92int udplite_get_port(struct sock *sk, unsigned short snum,
93 int (*scmp)(const struct sock *, const struct sock *));
94#endif /* _UDPLITE_H */