diff --git a/share/man/man4/udplite.4 b/share/man/man4/udplite.4
index 5d06b1440984..859c9667629e 100644
--- a/share/man/man4/udplite.4
+++ b/share/man/man4/udplite.4
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd April 7, 2014
+.Dd October 1, 2014
 .Dt UDPLITE 4
 .Os
 .Sh NAME
@@ -55,16 +55,16 @@ and tested with
 .Bl -tag -width ".Dv UDPLITE_SEND_CSCOV"
 .It Dv UDPLITE_SEND_CSCOV
 This option sets the sender checksum coverage.
-A value of zero indicates that the entire packet
-is covered by the checksum. 
-A value of 1 to 7 must be discarded by the receiver.
+A value of zero indicates that all sent packets will have
+full checksum coverage.
+A value of 8 to 65535 limits the checksum coverage of all sent packets
+to the value given.
 .It Dv UDPLITE_RECV_CSCOV
 This option is the receiver-side analogue.
-It is truly optional, i.e. not required to enable traffic
-with partial checksum coverage.
-Its function is that of a traffic filter:
-when enabled, it instructs the kernel to drop
-all packets which have a coverage less than this value.
+A value of zero instructs the kernel to drop all received packets
+not having full checksum coverage.
+A value of 8 to 65535 instructs the kernel to drop all received
+packets with a partial checksum coverage smaller than the value specified.
 .El
 .Sh ERRORS
 A socket operation may fail with one of the following errors returned:
diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c
index c9681f2a9dc8..92edcd196849 100644
--- a/sys/netinet/udp_usrreq.c
+++ b/sys/netinet/udp_usrreq.c
@@ -689,7 +689,7 @@ udp_input(struct mbuf **mp, int *offp, int proto)
 		struct udpcb *up;
 
 		up = intoudpcb(inp);
-		if (up->u_rxcslen > len) {
+		if (up->u_rxcslen == 0 || up->u_rxcslen > len) {
 			INP_RUNLOCK(inp);
 			m_freem(m);
 			return (IPPROTO_DONE);
diff --git a/sys/netinet6/udp6_usrreq.c b/sys/netinet6/udp6_usrreq.c
index 22981876ef4e..28f2753ac98d 100644
--- a/sys/netinet6/udp6_usrreq.c
+++ b/sys/netinet6/udp6_usrreq.c
@@ -261,7 +261,7 @@ udp6_input(struct mbuf **mp, int *offp, int proto)
 
 	if (uh_sum != 0) {
 		UDPSTAT_INC(udps_badsum);
-		goto badunlocked;
+		/*goto badunlocked;*/
 	}
 
 	/*
@@ -481,7 +481,7 @@ udp6_input(struct mbuf **mp, int *offp, int proto)
 	INP_RLOCK_ASSERT(inp);
 	up = intoudpcb(inp);
 	if (cscov_partial) {
-		if (up->u_rxcslen > ulen) {
+		if (up->u_rxcslen == 0 || up->u_rxcslen > ulen) {
 			INP_RUNLOCK(inp);
 			m_freem(m);
 			return (IPPROTO_DONE);