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-rw-r--r--include/net/udplite.h151
1 files changed, 151 insertions, 0 deletions
diff --git a/include/net/udplite.h b/include/net/udplite.h
new file mode 100644
index 0000000..67ac514
--- /dev/null
+++ b/include/net/udplite.h
@@ -0,0 +1,151 @@
+/*
+ * 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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