diff --git a/cddl/lib/libdtrace/Makefile b/cddl/lib/libdtrace/Makefile
index ff1a220..bb7801d 100644
--- a/cddl/lib/libdtrace/Makefile
+++ b/cddl/lib/libdtrace/Makefile
@@ -51,6 +51,7 @@ DSRCS=		errno.d			\
 		ip.d			\
 		psinfo.d		\
 		signal.d		\
+		udp.d			\
 		unistd.d
 
 WARNS?=		1
diff --git a/cddl/lib/libdtrace/ip.d b/cddl/lib/libdtrace/ip.d
index c898397..48fcc10 100644
--- a/cddl/lib/libdtrace/ip.d
+++ b/cddl/lib/libdtrace/ip.d
@@ -170,6 +170,9 @@ inline short IPPROTO_SCTP =	132;
 #pragma D binding "1.0" IPPROTO_RAW
 inline short IPPROTO_RAW =	255;
 
+inline uint8_t INP_IPV4	= 0x01;
+inline uint8_t INP_IPV6 = 0x02;
+
 #pragma D binding "1.0" protocols
 inline string protocols[int proto] =
 	proto == IPPROTO_IP ? "IP" :
diff --git a/cddl/lib/libdtrace/udp.d b/cddl/lib/libdtrace/udp.d
new file mode 100644
index 0000000..9e24704
--- /dev/null
+++ b/cddl/lib/libdtrace/udp.d
@@ -0,0 +1,81 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
+ */
+/*
+ * Copyright (c) 2013 Mark Johnston <markj@FreeBSD.org>
+ */
+
+#pragma D depends_on library ip.d
+#pragma D depends_on provider udp
+
+/*
+ * udpsinfo contains stable UDP details.
+ */
+typedef struct udpsinfo {
+	uintptr_t udps_addr;
+	uint16_t udps_lport;		/* local port */
+	uint16_t udps_rport;		/* remote port */
+	string udps_laddr;		/* local address, as a string */
+	string udps_raddr;		/* remote address, as a string */
+} udpsinfo_t;
+
+/*
+ * udpinfo is the UDP header fields.
+ */
+typedef struct udpinfo {
+	uint16_t udp_sport;		/* source port */
+	uint16_t udp_dport;		/* destination port */
+	uint16_t udp_length;		/* total length */
+	uint16_t udp_checksum;          /* headers + data checksum */
+	struct udphdr *udp_hdr;		/* raw UDP header */
+} udpinfo_t;
+
+/* The translator for struct mbuf * to ipinfo_t * is in ip.d. */
+
+#pragma D binding "1.0" translator
+translator udpsinfo_t < struct inpcb *p > {
+	udps_addr =	(uintptr_t)p;
+	udps_lport =	p == NULL ? 0 : ntohs(p->inp_inc.inc_ie.ie_lport);
+	udps_rport =	p == NULL ? 0 : ntohs(p->inp_inc.inc_ie.ie_fport);
+	udps_laddr =	p == NULL ? "" :
+	    p->inp_vflag == INP_IPV4 ?
+	    inet_ntoa(&p->inp_inc.inc_ie.ie_dependladdr.ie46_local.ia46_addr4.s_addr) :
+	    p->inp_vflag == INP_IPV6 ?
+	    inet_ntoa6(&p->inp_inc.inc_ie.ie_dependladdr.ie6_local) :
+	    "<unknown>";
+	udps_raddr =	p == NULL ? "" :
+	    p->inp_vflag == INP_IPV4 ?
+	    inet_ntoa(&p->inp_inc.inc_ie.ie_dependfaddr.ie46_foreign.ia46_addr4.s_addr) :
+	    p->inp_vflag == INP_IPV6 ?
+	    inet_ntoa6(&p->inp_inc.inc_ie.ie_dependfaddr.ie6_foreign) :
+	    "<unknown>";
+};
+
+#pragma D binding "1.0" translator
+translator udpinfo_t < struct udphdr *p > {
+	udp_sport =	p == NULL ? 0 : ntohs(p->uh_sport);
+	udp_dport =	p == NULL ? 0 : ntohs(p->uh_dport);
+	udp_length =	p == NULL ? 0 : ntohs(p->uh_ulen);
+	udp_checksum =	p == NULL ? 0 : ntohs(p->uh_sum);
+	udp_hdr =	p;
+};
diff --git a/sys/cddl/contrib/opensolaris/uts/common/dtrace/sdt_subr.c b/sys/cddl/contrib/opensolaris/uts/common/dtrace/sdt_subr.c
index ef938d4..a1fc2b1 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/dtrace/sdt_subr.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/dtrace/sdt_subr.c
@@ -92,6 +92,7 @@ sdt_provider_t sdt_providers[] = {
 	{ "proc", "__proc_", &stab_attr, 0 },
 	{ "io", "__io_", &stab_attr, 0 },
 	{ "ip", "__ip_", &stab_attr, 0 },
+	{ "udp", "__udp_", &stab_attr, 0 },
 	{ "mib", "__mib_", &stab_attr, 0 },
 	{ "fsinfo", "__fsinfo_", &fsinfo_attr, 0 },
 	{ "nfsv3", "__nfsv3_", &stab_attr, 0 },
@@ -801,6 +802,16 @@ sdt_argdesc_t sdt_args[] = {
 	{ "ip", "receive", 3, 3, "struct ifnet *", "ifinfo_t *" },
 	{ "ip", "receive", 4, 4, "struct ip *", "ipv4info_t *" },
 	{ "ip", "receive", 5, 5, "struct ip6_hdr *", "ipv6info_t *" },
+	{ "udp", "send", 0, 0, "void *", "void *" },
+	{ "udp", "send", 1, 1, "void *", "void *" },
+	{ "udp", "send", 2, 2, "struct mbuf *", "ipinfo_t *" },
+	{ "udp", "send", 3, 3, "struct inpcb *", "udpsinfo_t *" },
+	{ "udp", "send", 4, 4, "struct udphdr *", "udpinfo_t *" },
+	{ "udp", "receive", 0, 0, "void *", "void *" },
+	{ "udp", "receive", 1, 1, "void *", "void *" },
+	{ "udp", "receive", 2, 2, "struct mbuf *", "ipinfo_t *" },
+	{ "udp", "receive", 3, 3, "struct inpcb *", "udpsinfo_t *" },
+	{ "udp", "receive", 4, 4, "struct udphdr *", "udpinfo_t *" },
 
 	{ "sysevent", "post", 0, 0, "evch_bind_t *", "syseventchaninfo_t *" },
 	{ "sysevent", "post", 1, 1, "sysevent_impl_t *", "syseventinfo_t *" },
diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c
index b6297dc..597f77f 100644
--- a/sys/netinet/udp_usrreq.c
+++ b/sys/netinet/udp_usrreq.c
@@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$");
 #include "opt_inet.h"
 #include "opt_inet6.h"
 #include "opt_ipsec.h"
+#include "opt_kdtrace.h"
 
 #include <sys/param.h>
 #include <sys/domain.h>
@@ -54,6 +55,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/priv.h>
 #include <sys/proc.h>
 #include <sys/protosw.h>
+#include <sys/sdt.h>
 #include <sys/signalvar.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
@@ -163,6 +165,13 @@ static struct mbuf *udp4_espdecap(struct inpcb *, struct mbuf *, int);
 #endif /* IPSEC_NAT_T */
 #endif /* IPSEC */
 
+SDT_PROVIDER_DEFINE(udp);
+
+SDT_PROBE_DEFINE5(udp, , , send, send, "void *", "void *", "struct mbuf *",
+    "struct inpcb *", "struct udphdr *");
+SDT_PROBE_DEFINE5(udp, , , receive, receive, "void *", "void *",
+    "struct mbuf *", "struct inpcb *", "struct udphdr *");
+
 static void
 udp_zone_change(void *tag)
 {
@@ -370,6 +379,8 @@ udp_input(struct mbuf *m, int off)
 	}
 	uh = (struct udphdr *)((caddr_t)ip + iphlen);
 
+	SDT_PROBE5(udp, , , receive, 0, ip, m, ip, uh);
+
 	/*
 	 * Destination port of 0 is illegal, based on RFC768.
 	 */
@@ -1190,6 +1201,7 @@ udp_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr,
 	 */
 	ui = mtod(m, struct udpiphdr *);
 	bzero(ui->ui_x1, sizeof(ui->ui_x1));	/* XXX still needed? */
+	ui->ui_v = IPVERSION << 4;
 	ui->ui_pr = IPPROTO_UDP;
 	ui->ui_src = laddr;
 	ui->ui_dst = faddr;
@@ -1240,6 +1252,7 @@ udp_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr,
 		INP_HASH_WUNLOCK(&V_udbinfo);
 	else if (unlock_udbinfo == UH_RLOCKED)
 		INP_HASH_RUNLOCK(&V_udbinfo);
+	SDT_PROBE5(udp, , , send, 0, inp, m, inp, &ui->ui_u);
 	error = ip_output(m, inp->inp_options, NULL, ipflags,
 	    inp->inp_moptions, inp);
 	if (unlock_udbinfo == UH_WLOCKED)
diff --git a/sys/netinet/udp_var.h b/sys/netinet/udp_var.h
index e4a6668..683affe 100644
--- a/sys/netinet/udp_var.h
+++ b/sys/netinet/udp_var.h
@@ -42,6 +42,7 @@ struct udpiphdr {
 	struct udphdr	ui_u;		/* udp header */
 };
 #define	ui_x1		ui_i.ih_x1
+#define	ui_v		ui_i.ih_x1[0]
 #define	ui_pr		ui_i.ih_pr
 #define	ui_len		ui_i.ih_len
 #define	ui_src		ui_i.ih_src
diff --git a/sys/netinet6/udp6_usrreq.c b/sys/netinet6/udp6_usrreq.c
index 200fd68..79df47b 100644
--- a/sys/netinet6/udp6_usrreq.c
+++ b/sys/netinet6/udp6_usrreq.c
@@ -73,6 +73,7 @@ __FBSDID("$FreeBSD$");
 #include "opt_inet6.h"
 #include "opt_ipfw.h"
 #include "opt_ipsec.h"
+#include "opt_kdtrace.h"
 
 #include <sys/param.h>
 #include <sys/jail.h>
@@ -82,6 +83,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/priv.h>
 #include <sys/proc.h>
 #include <sys/protosw.h>
+#include <sys/sdt.h>
 #include <sys/signalvar.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
@@ -120,6 +122,11 @@ __FBSDID("$FreeBSD$");
 
 #include <security/mac/mac_framework.h>
 
+SDT_PROVIDER_DECLARE(udp);
+
+SDT_PROBE_DECLARE(udp, , , receive);
+SDT_PROBE_DECLARE(udp, , , send);
+
 /*
  * UDP protocol implementation.
  * Per RFC 768, August, 1980.
@@ -377,6 +384,7 @@ udp6_input(struct mbuf **mp, int *offp, int proto)
 		INP_RLOCK(last);
 		INP_INFO_RUNLOCK(&V_udbinfo);
 		up = intoudpcb(last);
+		SDT_PROBE5(udp, , , receive, 0, last, m, last, uh);
 		if (up->u_tun_func == NULL) {
 			udp6_append(last, m, off, &fromsa);
 		} else {
@@ -455,6 +463,7 @@ udp6_input(struct mbuf **mp, int *offp, int proto)
 	}
 	INP_RLOCK_ASSERT(inp);
 	up = intoudpcb(inp);
+	SDT_PROBE5(udp, , , receive, 0, inp, m, inp, uh);
 	if (up->u_tun_func == NULL) {
 		udp6_append(inp, m, off, &fromsa);
 	} else {
@@ -785,6 +794,7 @@ udp6_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr6,
 
 		flags = 0;
 
+		SDT_PROBE5(udp, , , send, 0, inp, m, inp, udp6);
 		UDPSTAT_INC(udps_opackets);
 		error = ip6_output(m, optp, NULL, flags, inp->in6p_moptions,
 		    NULL, inp);