diff options
Diffstat (limited to 'include/net/udplite.h')
| -rw-r--r-- | include/net/udplite.h | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/include/net/udplite.h b/include/net/udplite.h new file mode 100644 index 00000000..71375459 --- /dev/null +++ b/include/net/udplite.h @@ -0,0 +1,132 @@ +/* + * 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; +} + +/* Slow-path computation of checksum. Socket is locked. */ +static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb) +{ + const struct udp_sock *up = udp_sk(skb->sk); + int cscov = up->len; + __wsum csum = 0; + + if (up->pcflag & UDPLITE_SEND_CC) { + /* + * Sender has set `partial coverage' option on UDP-Lite socket. + * The special case "up->pcslen == 0" signifies full coverage. + */ + if (up->pcslen < up->len) { + if (0 < up->pcslen) + cscov = up->pcslen; + udp_hdr(skb)->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. + */ + } + + 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; +} + +/* Fast-path computation of checksum. Socket may not be locked. */ +static inline __wsum udplite_csum(struct sk_buff *skb) +{ + const struct udp_sock *up = udp_sk(skb->sk); + const int off = skb_transport_offset(skb); + int len = skb->len - off; + + if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) { + if (0 < up->pcslen) + len = up->pcslen; + udp_hdr(skb)->len = htons(up->pcslen); + } + skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */ + + return skb_checksum(skb, off, len, 0); +} + +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 */ |