diff options
Diffstat (limited to 'include/net/udplite.h')
| -rw-r--r-- | include/net/udplite.h | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/include/net/udplite.h b/include/net/udplite.h new file mode 100644 index 0000000..1473b3e --- /dev/null +++ b/include/net/udplite.h @@ -0,0 +1,149 @@ +/* + * 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 u32 udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb) +{ + u32 csum = 0; + int off, len, cscov = udplite_sender_cscov(udp_sk(sk), skb->h.uh); + + 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 */ |
