1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
|
/*
* Definitions for the UDP-Lite (RFC 3828) code.
*/
#ifndef _UDPLITE_H
#define _UDPLITE_H
/* UDP-Lite socket options */
#define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */
#define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */
extern struct proto udplite_prot;
extern struct hlist_head udplite_hash[UDP_HTABLE_SIZE];
/* UDP-Lite does not have a standardized MIB yet, so we inherit from UDP */
DECLARE_SNMP_STAT(struct udp_mib, udplite_statistics);
/*
* Checksum computation is all in software, hence simpler getfrag.
*/
static __inline__ int udplite_getfrag(void *from, char *to, int offset,
int len, int odd, struct sk_buff *skb)
{
return memcpy_fromiovecend(to, (struct iovec *) from, offset, len);
}
/* Designate sk as UDP-Lite socket */
static inline int udplite_sk_init(struct sock *sk)
{
udp_sk(sk)->pcflag = UDPLITE_BIT;
return 0;
}
/*
* Checksumming routines
*/
static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
{
u16 cscov;
/* In UDPv4 a zero checksum means that the transmitter generated no
* checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
* with a zero checksum field are illegal. */
if (uh->check == 0) {
LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: zeroed checksum field\n");
return 1;
}
UDP_SKB_CB(skb)->partial_cov = 0;
cscov = ntohs(uh->len);
if (cscov == 0) /* Indicates that full coverage is required. */
cscov = skb->len;
else if (cscov < 8 || cscov > skb->len) {
/*
* Coverage length violates RFC 3828: log and discard silently.
*/
LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: bad csum coverage %d/%d\n",
cscov, skb->len);
return 1;
} else if (cscov < skb->len)
UDP_SKB_CB(skb)->partial_cov = 1;
UDP_SKB_CB(skb)->cscov = cscov;
/*
* There is no known NIC manufacturer supporting UDP-Lite yet,
* hence ip_summed is always (re-)set to CHECKSUM_NONE.
*/
skb->ip_summed = CHECKSUM_NONE;
return 0;
}
static __inline__ int udplite4_csum_init(struct sk_buff *skb, struct udphdr *uh)
{
int rc = udplite_checksum_init(skb, uh);
if (!rc)
skb->csum = csum_tcpudp_nofold(skb->nh.iph->saddr,
skb->nh.iph->daddr,
skb->len, IPPROTO_UDPLITE, 0);
return rc;
}
static __inline__ int udplite6_csum_init(struct sk_buff *skb, struct udphdr *uh)
{
int rc = udplite_checksum_init(skb, uh);
if (!rc)
skb->csum = ~csum_ipv6_magic(&skb->nh.ipv6h->saddr,
&skb->nh.ipv6h->daddr,
skb->len, IPPROTO_UDPLITE, 0);
return rc;
}
static inline int udplite_sender_cscov(struct udp_sock *up, struct udphdr *uh)
{
int cscov = up->len;
/*
* Sender has set `partial coverage' option on UDP-Lite socket
*/
if (up->pcflag & UDPLITE_SEND_CC) {
if (up->pcslen < up->len) {
/* up->pcslen == 0 means that full coverage is required,
* partial coverage only if 0 < up->pcslen < up->len */
if (0 < up->pcslen) {
cscov = up->pcslen;
}
uh->len = htons(up->pcslen);
}
/*
* NOTE: Causes for the error case `up->pcslen > up->len':
* (i) Application error (will not be penalized).
* (ii) Payload too big for send buffer: data is split
* into several packets, each with its own header.
* In this case (e.g. last segment), coverage may
* exceed packet length.
* Since packets with coverage length > packet length are
* illegal, we fall back to the defaults here.
*/
}
return cscov;
}
static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
{
int off, len, cscov = udplite_sender_cscov(udp_sk(sk), skb->h.uh);
__wsum csum = 0;
skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
skb_queue_walk(&sk->sk_write_queue, skb) {
off = skb->h.raw - skb->data;
len = skb->len - off;
csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum);
if ((cscov -= len) <= 0)
break;
}
return csum;
}
extern void udplite4_register(void);
extern int udplite_get_port(struct sock *sk, unsigned short snum,
int (*scmp)(const struct sock *, const struct sock *));
#endif /* _UDPLITE_H */
|
