/* *	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 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_unfold(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 */