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- /*
- * 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 */
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