1 files changed, 88 insertions, 0 deletions
diff --git a/include/net/udplite.h b/include/net/udplite.h
new file mode 100644
index 0000000000..786919d29f
--- /dev/null
+++ b/include/net/udplite.h
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *	Definitions for the UDP-Lite (RFC 3828) code.
+ */
+#ifndef _UDPLITE_H
+#define _UDPLITE_H
+
+#include <net/ip6_checksum.h>
+#include <net/udp.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)
+{
+	struct msghdr *msg = from;
+	return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
+}
+
+/*
+ * 	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) {
+		net_dbg_ratelimited("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.
+		 */
+		net_dbg_ratelimited("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;
+		skb->csum_valid = 0;
+        }
+
+	return 0;
+}
+
+/* Fast-path computation of checksum. Socket may not be locked. */
+static inline __wsum udplite_csum(struct sk_buff *skb)
+{
+	const int off = skb_transport_offset(skb);
+	const struct sock *sk = skb->sk;
+	int len = skb->len - off;
+
+	if (udp_test_bit(UDPLITE_SEND_CC, sk)) {
+		u16 pcslen = READ_ONCE(udp_sk(sk)->pcslen);
+
+		if (pcslen < len) {
+			if (pcslen > 0)
+				len = pcslen;
+			udp_hdr(skb)->len = htons(pcslen);
+		}
+	}
+	skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */
+
+	return skb_checksum(skb, off, len, 0);
+}
+
+void udplite4_register(void);
+#endif	/* _UDPLITE_H */