tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
fork
Configure Feed
Select the types of activity you want to include in your feed.
1/*
2 * Definitions for the UDP-Lite (RFC 3828) code.
3 */
4#ifndef _UDPLITE_H
5#define _UDPLITE_H
6
7#include <net/ip6_checksum.h>
8
9/* UDP-Lite socket options */
10#define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */
11#define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */
12
13extern struct proto udplite_prot;
14extern struct udp_table udplite_table;
15
16/*
17 * Checksum computation is all in software, hence simpler getfrag.
18 */
19static __inline__ int udplite_getfrag(void *from, char *to, int offset,
20 int len, int odd, struct sk_buff *skb)
21{
22 return memcpy_fromiovecend(to, (struct iovec *) from, offset, len);
23}
24
25/* Designate sk as UDP-Lite socket */
26static inline int udplite_sk_init(struct sock *sk)
27{
28 udp_sk(sk)->pcflag = UDPLITE_BIT;
29 return 0;
30}
31
32/*
33 * Checksumming routines
34 */
35static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
36{
37 u16 cscov;
38
39 /* In UDPv4 a zero checksum means that the transmitter generated no
40 * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
41 * with a zero checksum field are illegal. */
42 if (uh->check == 0) {
43 LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: zeroed checksum field\n");
44 return 1;
45 }
46
47 cscov = ntohs(uh->len);
48
49 if (cscov == 0) /* Indicates that full coverage is required. */
50 ;
51 else if (cscov < 8 || cscov > skb->len) {
52 /*
53 * Coverage length violates RFC 3828: log and discard silently.
54 */
55 LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: bad csum coverage %d/%d\n",
56 cscov, skb->len);
57 return 1;
58
59 } else if (cscov < skb->len) {
60 UDP_SKB_CB(skb)->partial_cov = 1;
61 UDP_SKB_CB(skb)->cscov = cscov;
62 if (skb->ip_summed == CHECKSUM_COMPLETE)
63 skb->ip_summed = CHECKSUM_NONE;
64 }
65
66 return 0;
67}
68
69static inline int udplite_sender_cscov(struct udp_sock *up, struct udphdr *uh)
70{
71 int cscov = up->len;
72
73 /*
74 * Sender has set `partial coverage' option on UDP-Lite socket
75 */
76 if (up->pcflag & UDPLITE_SEND_CC) {
77 if (up->pcslen < up->len) {
78 /* up->pcslen == 0 means that full coverage is required,
79 * partial coverage only if 0 < up->pcslen < up->len */
80 if (0 < up->pcslen) {
81 cscov = up->pcslen;
82 }
83 uh->len = htons(up->pcslen);
84 }
85 /*
86 * NOTE: Causes for the error case `up->pcslen > up->len':
87 * (i) Application error (will not be penalized).
88 * (ii) Payload too big for send buffer: data is split
89 * into several packets, each with its own header.
90 * In this case (e.g. last segment), coverage may
91 * exceed packet length.
92 * Since packets with coverage length > packet length are
93 * illegal, we fall back to the defaults here.
94 */
95 }
96 return cscov;
97}
98
99static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
100{
101 int cscov = udplite_sender_cscov(udp_sk(sk), udp_hdr(skb));
102 __wsum csum = 0;
103
104 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
105
106 skb_queue_walk(&sk->sk_write_queue, skb) {
107 const int off = skb_transport_offset(skb);
108 const int len = skb->len - off;
109
110 csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum);
111
112 if ((cscov -= len) <= 0)
113 break;
114 }
115 return csum;
116}
117
118extern void udplite4_register(void);
119extern int udplite_get_port(struct sock *sk, unsigned short snum,
120 int (*scmp)(const struct sock *, const struct sock *));
121#endif /* _UDPLITE_H */