122 lines
3.4 KiB
C
122 lines
3.4 KiB
C
/*
|
|
* Definitions for the UDP-Lite (RFC 3828) code.
|
|
*/
|
|
#ifndef _UDPLITE_H
|
|
#define _UDPLITE_H
|
|
|
|
#include <net/ip6_checksum.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 udp_table udplite_table;
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
cscov = ntohs(uh->len);
|
|
|
|
if (cscov == 0) /* Indicates that full coverage is required. */
|
|
;
|
|
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;
|
|
if (skb->ip_summed == CHECKSUM_COMPLETE)
|
|
skb->ip_summed = CHECKSUM_NONE;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
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 cscov = udplite_sender_cscov(udp_sk(sk), udp_hdr(skb));
|
|
__wsum csum = 0;
|
|
|
|
skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
|
|
|
|
skb_queue_walk(&sk->sk_write_queue, skb) {
|
|
const int off = skb_transport_offset(skb);
|
|
const int 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 */
|