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Gerrit Renkerba4e58e2006-11-27 11:10:57 -08001/*
2 * Definitions for the UDP-Lite (RFC 3828) code.
3 */
4#ifndef _UDPLITE_H
5#define _UDPLITE_H
6
David S. Miller6bb100b2006-11-15 01:09:32 -08007#include <net/ip6_checksum.h>
8
Gerrit Renkerba4e58e2006-11-27 11:10:57 -08009/* 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;
Eric Dumazet645ca702008-10-29 01:41:45 -070014extern struct udp_table udplite_table;
Gerrit Renkerba4e58e2006-11-27 11:10:57 -080015
Gerrit Renkerba4e58e2006-11-27 11:10:57 -080016/*
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{
Al Virof69e6d12014-11-24 13:23:40 -050022 struct msghdr *msg = from;
Al Viro21226ab2014-11-28 15:48:29 -050023 return copy_from_iter(to, len, &msg->msg_iter) != len ? -EFAULT : 0;
Gerrit Renkerba4e58e2006-11-27 11:10:57 -080024}
25
26/* Designate sk as UDP-Lite socket */
27static inline int udplite_sk_init(struct sock *sk)
28{
29 udp_sk(sk)->pcflag = UDPLITE_BIT;
30 return 0;
31}
32
33/*
34 * Checksumming routines
35 */
36static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
37{
38 u16 cscov;
39
40 /* In UDPv4 a zero checksum means that the transmitter generated no
41 * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
42 * with a zero checksum field are illegal. */
43 if (uh->check == 0) {
Joe Perchesba7a46f2014-11-11 10:59:17 -080044 net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
Gerrit Renkerba4e58e2006-11-27 11:10:57 -080045 return 1;
46 }
47
Gerrit Renkerba4e58e2006-11-27 11:10:57 -080048 cscov = ntohs(uh->len);
49
50 if (cscov == 0) /* Indicates that full coverage is required. */
Herbert Xu759e5d02007-03-25 20:10:56 -070051 ;
Gerrit Renkerba4e58e2006-11-27 11:10:57 -080052 else if (cscov < 8 || cscov > skb->len) {
53 /*
54 * Coverage length violates RFC 3828: log and discard silently.
55 */
Joe Perchesba7a46f2014-11-11 10:59:17 -080056 net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
57 cscov, skb->len);
Gerrit Renkerba4e58e2006-11-27 11:10:57 -080058 return 1;
59
Herbert Xu759e5d02007-03-25 20:10:56 -070060 } else if (cscov < skb->len) {
Gerrit Renkerba4e58e2006-11-27 11:10:57 -080061 UDP_SKB_CB(skb)->partial_cov = 1;
Herbert Xu759e5d02007-03-25 20:10:56 -070062 UDP_SKB_CB(skb)->cscov = cscov;
63 if (skb->ip_summed == CHECKSUM_COMPLETE)
64 skb->ip_summed = CHECKSUM_NONE;
Alexey Kodanev59849012018-02-15 20:18:43 +030065 skb->csum_valid = 0;
Herbert Xu759e5d02007-03-25 20:10:56 -070066 }
Gerrit Renkerba4e58e2006-11-27 11:10:57 -080067
68 return 0;
69}
70
Gerrit Renkerf36c23b2011-10-17 19:07:30 -040071/* Slow-path computation of checksum. Socket is locked. */
Al Viro868c86b2006-11-14 21:35:48 -080072static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
Gerrit Renkerba4e58e2006-11-27 11:10:57 -080073{
Gerrit Renkerf36c23b2011-10-17 19:07:30 -040074 const struct udp_sock *up = udp_sk(skb->sk);
75 int cscov = up->len;
Al Viro868c86b2006-11-14 21:35:48 -080076 __wsum csum = 0;
Gerrit Renkerba4e58e2006-11-27 11:10:57 -080077
Gerrit Renkerf36c23b2011-10-17 19:07:30 -040078 if (up->pcflag & UDPLITE_SEND_CC) {
79 /*
80 * Sender has set `partial coverage' option on UDP-Lite socket.
81 * The special case "up->pcslen == 0" signifies full coverage.
82 */
83 if (up->pcslen < up->len) {
84 if (0 < up->pcslen)
85 cscov = up->pcslen;
86 udp_hdr(skb)->len = htons(up->pcslen);
87 }
88 /*
89 * NOTE: Causes for the error case `up->pcslen > up->len':
90 * (i) Application error (will not be penalized).
91 * (ii) Payload too big for send buffer: data is split
92 * into several packets, each with its own header.
93 * In this case (e.g. last segment), coverage may
94 * exceed packet length.
95 * Since packets with coverage length > packet length are
96 * illegal, we fall back to the defaults here.
97 */
98 }
99
Gerrit Renkerba4e58e2006-11-27 11:10:57 -0800100 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
101
102 skb_queue_walk(&sk->sk_write_queue, skb) {
Arnaldo Carvalho de Meloea2ae172007-04-25 17:55:53 -0700103 const int off = skb_transport_offset(skb);
104 const int len = skb->len - off;
Gerrit Renkerba4e58e2006-11-27 11:10:57 -0800105
106 csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum);
107
108 if ((cscov -= len) <= 0)
109 break;
110 }
111 return csum;
112}
113
Gerrit Renkerf36c23b2011-10-17 19:07:30 -0400114/* Fast-path computation of checksum. Socket may not be locked. */
Herbert Xuf6b96642011-03-01 02:36:48 +0000115static inline __wsum udplite_csum(struct sk_buff *skb)
116{
Gerrit Renkerf36c23b2011-10-17 19:07:30 -0400117 const struct udp_sock *up = udp_sk(skb->sk);
Herbert Xuf6b96642011-03-01 02:36:48 +0000118 const int off = skb_transport_offset(skb);
Gerrit Renkerf36c23b2011-10-17 19:07:30 -0400119 int len = skb->len - off;
Herbert Xuf6b96642011-03-01 02:36:48 +0000120
Gerrit Renkerf36c23b2011-10-17 19:07:30 -0400121 if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
122 if (0 < up->pcslen)
123 len = up->pcslen;
124 udp_hdr(skb)->len = htons(up->pcslen);
125 }
Herbert Xuf6b96642011-03-01 02:36:48 +0000126 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
127
Gerrit Renkerf36c23b2011-10-17 19:07:30 -0400128 return skb_checksum(skb, off, len, 0);
Herbert Xuf6b96642011-03-01 02:36:48 +0000129}
130
Joe Perches16073432013-09-23 11:33:39 -0700131void udplite4_register(void);
132int udplite_get_port(struct sock *sk, unsigned short snum,
133 int (*scmp)(const struct sock *, const struct sock *));
Gerrit Renkerba4e58e2006-11-27 11:10:57 -0800134#endif /* _UDPLITE_H */