diff --git a/cddl/lib/libdtrace/Makefile b/cddl/lib/libdtrace/Makefile
index 4fd7fae..46f7046 100644
--- a/cddl/lib/libdtrace/Makefile
+++ b/cddl/lib/libdtrace/Makefile
@@ -48,8 +48,11 @@ SRCS=		dt_aggregate.c \
 
 DSRCS=		errno.d			\
 		io.d			\
+		ip.d			\
 		psinfo.d		\
 		signal.d		\
+		tcp.d			\
+		udp.d			\
 		unistd.d
 
 WARNS?=		1
diff --git a/cddl/lib/libdtrace/ip.d b/cddl/lib/libdtrace/ip.d
new file mode 100644
index 0000000..84d61f6
--- /dev/null
+++ b/cddl/lib/libdtrace/ip.d
@@ -0,0 +1,285 @@
+/*
+ * 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) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
+ */
+/*
+ * Copyright (c) 2013 Mark Johnston <markj@freebsd.org>
+ */
+
+#pragma D depends_on provider ip
+
+/*
+ * pktinfo is where packet ID info can be made available for deeper
+ * analysis if packet IDs become supported by the kernel in the future.
+ * The pkt_addr member is currently always NULL.
+ */
+typedef struct pktinfo {
+	uintptr_t pkt_addr;
+} pktinfo_t;
+
+/*
+ * csinfo is where connection state info is made available.
+ */
+typedef uint32_t zoneid_t;
+typedef struct csinfo {
+	uintptr_t cs_addr;
+	uint64_t cs_cid;
+	pid_t cs_pid;
+	zoneid_t cs_zoneid;
+} csinfo_t;
+
+/*
+ * ipinfo contains common IP info for both IPv4 and IPv6.
+ */
+typedef struct ipinfo {
+	uint8_t ip_ver;			/* IP version (4, 6) */
+	uint32_t ip_plength;		/* payload length */
+	string ip_saddr;		/* source address */
+	string ip_daddr;		/* destination address */
+} ipinfo_t;
+
+/*
+ * ifinfo contains network interface info.
+ */
+typedef struct ifinfo {
+	string if_name;			/* interface name */
+	int8_t if_local;		/* is delivered locally */
+	/*netstackid_t if_ipstack;*/	/* ipstack ID */
+	uintptr_t if_addr;		/* pointer to raw ill_t */
+} ifinfo_t;
+
+typedef uint32_t ipaddr_t;
+typedef struct {
+	uint8_t		ipha_version_and_hdr_length;
+	uint8_t		ipha_type_of_service;
+	uint16_t	ipha_length;
+	uint16_t	ipha_ident;
+	uint16_t	ipha_fragment_offset_and_flags;
+	uint8_t		ipha_ttl;
+	uint8_t		ipha_protocol;
+	uint16_t	ipha_hdr_checksum;
+	ipaddr_t	ipha_src;
+	ipaddr_t	ipha_dst;
+} ipha_t;
+
+/*
+ * ipv4info is a translated version of the IPv4 header (with raw pointer).
+ * These values are NULL if the packet is not IPv4.
+ */
+typedef struct ipv4info {
+	uint8_t ipv4_ver;		/* IP version (4) */
+	uint8_t ipv4_ihl;		/* header length, bytes */
+	uint8_t ipv4_tos;		/* type of service field */
+	uint16_t ipv4_length;		/* length (header + payload) */
+	uint16_t ipv4_ident;		/* identification */
+	uint8_t ipv4_flags;		/* IP flags */
+	uint16_t ipv4_offset;		/* fragment offset */
+	uint8_t ipv4_ttl;		/* time to live */
+	uint8_t ipv4_protocol;		/* next level protocol */
+	string ipv4_protostr;		/* next level protocol, as a string */
+	uint16_t ipv4_checksum;		/* header checksum */
+	ipaddr_t ipv4_src;		/* source address */
+	ipaddr_t ipv4_dst;		/* destination address */
+	string ipv4_saddr;		/* source address, string */
+	string ipv4_daddr;		/* destination address, string */
+	ipha_t *ipv4_hdr;		/* pointer to raw header */
+} ipv4info_t;
+
+/*
+ * ipv6info is a translated version of the IPv6 header (with raw pointer).
+ * These values are NULL if the packet is not IPv6.
+ */
+typedef struct in6_addr in6_addr_t;
+typedef struct ip6_hdr ip6_t;
+typedef struct ipv6info {
+	uint8_t ipv6_ver;		/* IP version (6) */
+	uint8_t ipv6_tclass;		/* traffic class */
+	uint32_t ipv6_flow;		/* flow label */
+	uint16_t ipv6_plen;		/* payload length */
+	uint8_t ipv6_nexthdr;		/* next header protocol */
+	string ipv6_nextstr;		/* next header protocol, as a string */
+	uint8_t ipv6_hlim;		/* hop limit */
+	in6_addr_t *ipv6_src;		/* source address */
+	in6_addr_t *ipv6_dst;		/* destination address */
+	string ipv6_saddr;		/* source address, string */
+	string ipv6_daddr;		/* destination address, string */
+	ip6_t *ipv6_hdr;		/* pointer to raw header */
+} ipv6info_t;
+
+#pragma D binding "1.0" IPPROTO_IP
+inline short IPPROTO_IP =	0;
+#pragma D binding "1.0" IPPROTO_ICMP
+inline short IPPROTO_ICMP =	1;
+#pragma D binding "1.0" IPPROTO_IGMP
+inline short IPPROTO_IGMP =	2;
+#pragma D binding "1.0" IPPROTO_IPV4
+inline short IPPROTO_IPV4 =	4;
+#pragma D binding "1.0" IPPROTO_TCP
+inline short IPPROTO_TCP =	6;
+#pragma D binding "1.0" IPPROTO_UDP
+inline short IPPROTO_UDP =	17;
+#pragma D binding "1.0" IPPROTO_IPV6
+inline short IPPROTO_IPV6 =	41;
+#pragma D binding "1.0" IPPROTO_ROUTING
+inline short IPPROTO_ROUTING =	43;
+#pragma D binding "1.0" IPPROTO_FRAGMENT
+inline short IPPROTO_FRAGMENT =	44;
+#pragma D binding "1.0" IPPROTO_RSVP
+inline short IPPROTO_RSVP =	46;
+#pragma D binding "1.0" IPPROTO_GRE
+inline short IPPROTO_GRE =	47;
+#pragma D binding "1.0" IPPROTO_ESP
+inline short IPPROTO_ESP =	50;
+#pragma D binding "1.0" IPPROTO_AH
+inline short IPPROTO_AH =	51;
+#pragma D binding "1.0" IPPROTO_MOBILE
+inline short IPPROTO_MOBILE =	55;
+#pragma D binding "1.0" IPPROTO_ICMPV6
+inline short IPPROTO_ICMPV6 =	58;
+#pragma D binding "1.0" IPPROTO_DSTOPTS
+inline short IPPROTO_DSTOPTS =	60;
+#pragma D binding "1.0" IPPROTO_ETHERIP
+inline short IPPROTO_ETHERIP =	97;
+#pragma D binding "1.0" IPPROTO_PIM
+inline short IPPROTO_PIM =	103;
+#pragma D binding "1.0" IPPROTO_IPCOMP
+inline short IPPROTO_IPCOMP =	108;
+#pragma D binding "1.0" IPPROTO_SCTP
+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" :
+	proto == IPPROTO_ICMP ? "ICMP" :
+	proto == IPPROTO_IGMP ? "IGMP" :
+	proto == IPPROTO_IPV4 ? "IPV4" :
+	proto == IPPROTO_TCP ? "TCP" :
+	proto == IPPROTO_UDP ? "UDP" :
+	proto == IPPROTO_IPV6 ? "IPV6" :
+	proto == IPPROTO_ROUTING ? "ROUTING" :
+	proto == IPPROTO_FRAGMENT ? "FRAGMENT" :
+	proto == IPPROTO_RSVP ? "RSVP" :
+	proto == IPPROTO_GRE ? "GRE" :
+	proto == IPPROTO_ESP ? "ESP" :
+	proto == IPPROTO_AH ? "AH" :
+	proto == IPPROTO_MOBILE ? "MOBILE" :
+	proto == IPPROTO_ICMPV6 ? "ICMPV6" :
+	proto == IPPROTO_DSTOPTS ? "DSTOPTS" :
+	proto == IPPROTO_ETHERIP ? "ETHERIP" :
+	proto == IPPROTO_PIM ? "PIM" :
+	proto == IPPROTO_IPCOMP ? "IPCOMP" :
+	proto == IPPROTO_SCTP ? "SCTP" :
+	proto == IPPROTO_RAW ? "RAW" :
+	"<unknown>";
+
+/*
+ * This field is always NULL according to the current definition of the ip
+ * probes.
+ */
+#pragma D binding "1.0" translator
+translator pktinfo_t < void *p > {
+	pkt_addr =	NULL;
+};
+
+#pragma D binding "1.0" translator
+translator csinfo_t < void *p > {
+	cs_addr =	NULL;
+	cs_cid =	(uint64_t)p;
+	cs_pid =	0;
+	cs_zoneid =	0;
+};
+
+#pragma D binding "1.0" translator
+translator csinfo_t < struct inpcb *p > {
+	cs_addr =       NULL;
+	cs_cid =        (uint64_t)p;
+	cs_pid =        0;	/* XXX */
+	cs_zoneid =     0;
+};
+
+#pragma D binding "1.0" translator
+translator ipinfo_t < uint8_t *p > {
+	ip_ver =	p == NULL ? 0 : ((struct ip *)p)->ip_v;
+	ip_plength =	p == NULL ? 0 :
+	    ((struct ip *)p)->ip_v == 4 ?
+	    ntohs(((struct ip *)p)->ip_len) - 20 /* IPv4 header size. */:
+	    ntohs(((struct ip6_hdr *)p)->ip6_ctlun.ip6_un1.ip6_un1_plen);
+	ip_saddr =	p == NULL ? 0 :
+	    ((struct ip *)p)->ip_v == 4 ?
+	    inet_ntoa(&((struct ip *)p)->ip_src.s_addr) :
+	    inet_ntoa6(&((struct ip6_hdr *)p)->ip6_src);
+	ip_daddr =	p == NULL ? 0 :
+	    ((struct ip *)p)->ip_v == 4 ?
+	    inet_ntoa(&((struct ip *)p)->ip_dst.s_addr) :
+	    inet_ntoa6(&((struct ip6_hdr *)p)->ip6_dst);
+};
+
+#pragma D binding "1.0" IFF_LOOPBACK
+inline int IFF_LOOPBACK =	0x8;
+
+#pragma D binding "1.0" translator
+translator ifinfo_t < struct ifnet *p > {
+	if_name =	p->if_xname;
+	if_local =	(p->if_flags & IFF_LOOPBACK) == 0 ? 0 : 1;
+	if_addr =	(uintptr_t)p;
+};
+
+#pragma D binding "1.0" translator
+translator ipv4info_t < struct ip *p > {
+	ipv4_ver =	p == NULL ? 0 : p->ip_v;
+	ipv4_ihl =	p == NULL ? 0 : p->ip_hl;
+	ipv4_tos =	p == NULL ? 0 : p->ip_tos;
+	ipv4_length =	p == NULL ? 0 : ntohs(p->ip_len);
+	ipv4_ident =	p == NULL ? 0 : ntohs(p->ip_id);
+	ipv4_flags =	p == NULL ? 0 : (p->ip_off & 0xe000);
+	ipv4_offset =	p == NULL ? 0 : p->ip_off;
+	ipv4_ttl =	p == NULL ? 0 : p->ip_ttl;
+	ipv4_protocol =	p == NULL ? 0 : p->ip_p;
+	ipv4_protostr = p == NULL ? "<null>" : protocols[p->ip_p];
+	ipv4_checksum =	p == NULL ? 0 : ntohs(p->ip_sum);
+	ipv4_src =	p == NULL ? 0 : (ipaddr_t)ntohl(p->ip_src.s_addr);
+	ipv4_dst =	p == NULL ? 0 : (ipaddr_t)ntohl(p->ip_dst.s_addr);
+	ipv4_saddr =	p == NULL ? 0 : inet_ntoa(&p->ip_src.s_addr);
+	ipv4_daddr =	p == NULL ? 0 : inet_ntoa(&p->ip_dst.s_addr);
+	ipv4_hdr =	(ipha_t *)p;
+};
+
+#pragma D binding "1.0" translator
+translator ipv6info_t < struct ip6_hdr *p > {
+	ipv6_ver =	p == NULL ? 0 : ((ntohl(p->ip6_ctlun.ip6_un1.ip6_un1_flow) & 0xf0000000) >> 28);
+	ipv6_tclass =	p == NULL ? 0 : ((ntohl(p->ip6_ctlun.ip6_un1.ip6_un1_flow) & 0x0ff00000) >> 20);
+	ipv6_flow =	p == NULL ? 0 :  (ntohl(p->ip6_ctlun.ip6_un1.ip6_un1_flow) & 0x000fffff);
+	ipv6_plen =	p == NULL ? 0 : ntohs(p->ip6_ctlun.ip6_un1.ip6_un1_plen);
+	ipv6_nexthdr =	p == NULL ? 0 : p->ip6_ctlun.ip6_un1.ip6_un1_nxt;
+	ipv6_nextstr =	p == NULL ? "<null>" : protocols[p->ip6_ctlun.ip6_un1.ip6_un1_nxt];
+	ipv6_hlim =	p == NULL ? 0 : p->ip6_ctlun.ip6_un1.ip6_un1_hlim;
+	ipv6_src =	p == NULL ? 0 : (in6_addr_t *)&p->ip6_src;
+	ipv6_dst =	p == NULL ? 0 : (in6_addr_t *)&p->ip6_dst;
+	ipv6_saddr =	p == NULL ? 0 : inet_ntoa6(&p->ip6_src);
+	ipv6_daddr =	p == NULL ? 0 : inet_ntoa6(&p->ip6_dst);
+	ipv6_hdr =	(ip6_t *)p;
+};
diff --git a/cddl/lib/libdtrace/tcp.d b/cddl/lib/libdtrace/tcp.d
new file mode 100644
index 0000000..ef50333
--- /dev/null
+++ b/cddl/lib/libdtrace/tcp.d
@@ -0,0 +1,203 @@
+/*
+ * 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 tcp
+
+/*
+ * Convert a TCP state value to a string.
+ */
+#pragma D binding "1.0" TCPS_CLOSED
+inline int TCPS_CLOSED =	0;
+#pragma D binding "1.0" TCPS_LISTEN
+inline int TCPS_LISTEN =	1;
+#pragma D binding "1.0" TCPS_SYN_SENT
+inline int TCPS_SYN_SENT =	2;
+#pragma D binding "1.0" TCPS_SYN_RECEIVED
+inline int TCPS_SYN_RECEIVED =	3;
+#pragma D binding "1.0" TCPS_ESTABLISHED
+inline int TCPS_ESTABLISHED =	4;
+#pragma D binding "1.0" TCPS_CLOSE_WAIT
+inline int TCPS_CLOSE_WAIT =	5;
+#pragma D binding "1.0" TCPS_FIN_WAIT_1
+inline int TCPS_FIN_WAIT_1 =	6;
+#pragma D binding "1.0" TCPS_CLOSING
+inline int TCPS_CLOSING =	7;
+#pragma D binding "1.0" TCPS_LAST_ACK
+inline int TCPS_LAST_ACK =	8;
+#pragma D binding "1.0" TCPS_FIN_WAIT_2
+inline int TCPS_FIN_WAIT_2 =	9;
+#pragma D binding "1.0" TCPS_TIME_WAIT
+inline int TCPS_TIME_WAIT =	10;
+
+/* TCP segment flags. */
+#pragma D binding "1.0" TH_FIN
+inline uint8_t TH_FIN =		0x01;
+#pragma D binding "1.0" TH_SYN
+inline uint8_t TH_SYN =		0x02;
+#pragma D binding "1.0" TH_RST
+inline uint8_t TH_RST =		0x04;
+#pragma D binding "1.0" TH_PUSH
+inline uint8_t TH_PUSH =	0x08;
+#pragma D binding "1.0" TH_ACK
+inline uint8_t TH_ACK =		0x10;
+#pragma D binding "1.0" TH_URG
+inline uint8_t TH_URG =		0x20;
+#pragma D binding "1.0" TH_ECE
+inline uint8_t TH_ECE =		0x40;
+#pragma D binding "1.0" TH_CWR
+inline uint8_t TH_CWR =		0x80;
+
+/* TCP connection state strings. */
+#pragma D binding "1.0" tcp_state_string
+inline string tcp_state_string[int32_t state] =
+	state == TCPS_CLOSED ?		"state-closed" :
+	state == TCPS_LISTEN ?		"state-listen" :
+	state == TCPS_SYN_SENT ?	"state-syn-sent" :
+	state == TCPS_SYN_RECEIVED ?	"state-syn-received" :
+	state == TCPS_ESTABLISHED ?	"state-established" :
+	state == TCPS_CLOSE_WAIT ?	"state-close-wait" :
+	state == TCPS_FIN_WAIT_1 ?	"state-fin-wait-1" :
+	state == TCPS_CLOSING ?		"state-closing" :
+	state == TCPS_LAST_ACK ?	"state-last-ack" :
+	state == TCPS_FIN_WAIT_2 ?	"state-fin-wait-2" :
+	state == TCPS_TIME_WAIT ?	"state-time-wait" :
+	"<unknown>";
+
+/*
+ * tcpsinfo contains stable TCP details from tcp_t.
+ */
+typedef struct tcpsinfo {
+	uintptr_t tcps_addr;
+	int tcps_local;			/* is delivered locally, boolean */
+	int tcps_active;		/* active open (from here), boolean */
+	uint16_t tcps_lport;		/* local port */
+	uint16_t tcps_rport;		/* remote port */
+	string tcps_laddr;		/* local address, as a string */
+	string tcps_raddr;		/* remote address, as a string */
+	int32_t tcps_state;		/* TCP state */
+	uint32_t tcps_iss;		/* Initial sequence # sent */
+	uint32_t tcps_suna;		/* sequence # sent but unacked */
+	uint32_t tcps_snxt;		/* next sequence # to send */
+	uint32_t tcps_rack;		/* sequence # we have acked */
+	uint32_t tcps_rnxt;		/* next sequence # expected */
+	uint32_t tcps_swnd;		/* send window size */
+	int32_t tcps_snd_ws;		/* send window scaling */
+	uint32_t tcps_rwnd;		/* receive window size */
+	int32_t tcps_rcv_ws;		/* receive window scaling */
+	uint32_t tcps_cwnd;		/* congestion window */
+	uint32_t tcps_cwnd_ssthresh;	/* threshold for congestion avoidance */
+	uint32_t tcps_sack_fack;	/* SACK sequence # we have acked */
+	uint32_t tcps_sack_snxt;	/* next SACK seq # for retransmission */
+	uint32_t tcps_rto;		/* round-trip timeout, msec */
+	uint32_t tcps_mss;		/* max segment size */
+	int tcps_retransmit;		/* retransmit send event, boolean */
+} tcpsinfo_t;
+
+/*
+ * tcplsinfo provides the old tcp state for state changes.
+ */
+typedef struct tcplsinfo {
+	int32_t tcps_state;		/* previous TCP state */
+} tcplsinfo_t;
+
+/*
+ * tcpinfo is the TCP header fields.
+ */
+typedef struct tcpinfo {
+	uint16_t tcp_sport;		/* source port */
+	uint16_t tcp_dport;		/* destination port */
+	uint32_t tcp_seq;		/* sequence number */
+	uint32_t tcp_ack;		/* acknowledgment number */
+	uint8_t tcp_offset;		/* data offset, in bytes */
+	uint8_t tcp_flags;		/* flags */
+	uint16_t tcp_window;		/* window size */
+	uint16_t tcp_checksum;		/* checksum */
+	uint16_t tcp_urgent;		/* urgent data pointer */
+	struct tcphdr *tcp_hdr;		/* raw TCP header */
+} tcpinfo_t;
+
+#pragma D binding "1.0" translator
+translator csinfo_t < struct tcpcb *p > {
+	cs_addr =	NULL;
+	cs_cid =	(uint64_t)p;
+	cs_pid =	0;
+	cs_zoneid =	0;
+};
+
+#pragma D binding "1.0" translator
+translator tcpsinfo_t < struct tcpcb *p > {
+	tcps_addr =		(uintptr_t)p;
+	tcps_local =		-1; /* XXX */
+	tcps_active =		-1; /* XXX */
+	tcps_lport =		p == NULL ? 0 : ntohs(p->t_inpcb->inp_inc.inc_ie.ie_lport);
+	tcps_rport =		p == NULL ? 0 : ntohs(p->t_inpcb->inp_inc.inc_ie.ie_fport);
+	tcps_laddr =		p == NULL ? 0 :
+	    p->t_inpcb->inp_vflag == INP_IPV4 ?
+	    inet_ntoa(&p->t_inpcb->inp_inc.inc_ie.ie_dependladdr.ie46_local.ia46_addr4.s_addr) :
+	    inet_ntoa6(&p->t_inpcb->inp_inc.inc_ie.ie_dependladdr.ie6_local);
+	tcps_raddr =		p == NULL ? 0 :
+	    p->t_inpcb->inp_vflag == INP_IPV4 ?
+	    inet_ntoa(&p->t_inpcb->inp_inc.inc_ie.ie_dependfaddr.ie46_foreign.ia46_addr4.s_addr) :
+	    inet_ntoa6(&p->t_inpcb->inp_inc.inc_ie.ie_dependfaddr.ie6_foreign);
+	tcps_state =		p == NULL ? -1 : p->t_state;
+	tcps_iss =		p == NULL ? 0  : p->iss;
+	tcps_suna =		p == NULL ? 0  : p->snd_una;
+	tcps_snxt =		p == NULL ? 0  : p->snd_nxt;
+	tcps_rack =		p == NULL ? 0  : p->last_ack_sent;
+	tcps_rnxt =		p == NULL ? 0  : p->rcv_nxt;
+	tcps_swnd =		p == NULL ? -1  : p->snd_wnd;
+	tcps_snd_ws =		p == NULL ? -1  : p->snd_scale;
+	tcps_rwnd =		p == NULL ? -1  : p->rcv_wnd;
+	tcps_rcv_ws =		p == NULL ? -1  : p->rcv_scale;
+	tcps_cwnd =		p == NULL ? -1  : p->snd_cwnd;
+	tcps_cwnd_ssthresh =	p == NULL ? -1  : p->snd_ssthresh;
+	tcps_sack_fack =	p == NULL ? 0  : p->snd_fack;
+	tcps_sack_snxt =	p == NULL ? 0  : p->sack_newdata;
+	tcps_rto =		p == NULL ? -1  : p->t_rxtcur / 1000; /* XXX */
+	tcps_mss =		p == NULL ? -1  : p->t_maxseg;
+	tcps_retransmit =	-1; /* XXX */
+};
+
+#pragma D binding "1.0" translator
+translator tcpinfo_t < struct tcphdr *p > {
+	tcp_sport =	p == NULL ? 0  : ntohs(p->th_sport);
+	tcp_dport =	p == NULL ? 0  : ntohs(p->th_dport);
+	tcp_seq =	p == NULL ? -1 : ntohl(p->th_seq);
+	tcp_ack =	p == NULL ? -1 : ntohl(p->th_ack);
+	tcp_offset =	p == NULL ? -1 : (p->th_off >> 2);
+	tcp_flags =	p == NULL ? 0  : p->th_flags;
+	tcp_window =	p == NULL ? 0  : ntohs(p->th_win);
+	tcp_checksum =	p == NULL ? 0  : ntohs(p->th_sum);
+	tcp_urgent =	p == NULL ? 0  : ntohs(p->th_urp);
+	tcp_hdr =	(struct tcphdr *)p;
+};
+
+#pragma D binding "1.0" translator
+translator tcplsinfo_t < int s > {
+	tcps_state =	s;
+};
diff --git a/cddl/lib/libdtrace/udp.d b/cddl/lib/libdtrace/udp.d
new file mode 100644
index 0000000..506841946
--- /dev/null
+++ b/cddl/lib/libdtrace/udp.d
@@ -0,0 +1,75 @@
+/*
+ * 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;
+
+#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) :
+	    inet_ntoa6(&p->inp_inc.inc_ie.ie_dependladdr.ie6_local);
+	udps_raddr =	p == NULL ? "" :
+	    p->inp_vflag == INP_IPV4 ?
+	    inet_ntoa(&p->inp_inc.inc_ie.ie_dependfaddr.ie46_foreign.ia46_addr4.s_addr) :
+	    inet_ntoa6(&p->inp_inc.inc_ie.ie_dependfaddr.ie6_foreign);
+};
+
+#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/conf/files b/sys/conf/files
index c149fdd..089eea6 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -3228,6 +3228,7 @@ netinet/if_ether.c		optional inet ether
 netinet/igmp.c			optional inet
 netinet/in.c			optional inet
 netinet/in_debug.c		optional inet ddb
+netinet/in_kdtrace.c		optional inet | inet6
 netinet/ip_carp.c		optional inet carp | inet6 carp
 netinet/in_gif.c		optional gif inet | netgraph_gif inet
 netinet/ip_gre.c		optional gre inet
diff --git a/sys/netinet/in_kdtrace.c b/sys/netinet/in_kdtrace.c
new file mode 100644
index 0000000..85a5a4e
--- /dev/null
+++ b/sys/netinet/in_kdtrace.c
@@ -0,0 +1,127 @@
+/*-
+ * Copyright (c) 2013 Mark Johnston <markj@FreeBSD.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "opt_kdtrace.h"
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/sdt.h>
+
+SDT_PROVIDER_DEFINE(ip);
+SDT_PROVIDER_DEFINE(tcp);
+SDT_PROVIDER_DEFINE(udp);
+
+SDT_PROBE_DEFINE6_XLATE(ip, , , receive, receive,
+    "void *", "pktinfo_t *",
+    "void *", "csinfo_t *",
+    "uint8_t *", "ipinfo_t *",
+    "struct ifnet *", "ifinfo_t *",
+    "struct ip *", "ipv4info_t *",
+    "struct ip6_hdr *", "ipv6info_t *");
+
+SDT_PROBE_DEFINE6_XLATE(ip, , , send, send,
+    "void *", "pktinfo_t *",
+    "void *", "csinfo_t *",
+    "uint8_t *", "ipinfo_t *",
+    "struct ifnet *", "ifinfo_t *",
+    "struct ip *", "ipv4info_t *",
+    "struct ip6_hdr *", "ipv6info_t *");
+
+SDT_PROBE_DEFINE5_XLATE(tcp, , , accept_established, accept-established,
+    "void *", "pktinfo_t *",
+    "struct tcpcb *", "csinfo_t *",
+    "uint8_t *", "ipinfo_t *",
+    "struct tcpcb *", "tcpsinfo_t *" ,
+    "struct tcphdr *", "tcpinfo_t *");
+
+SDT_PROBE_DEFINE5_XLATE(tcp, , , accept_refused, accept-refused,
+    "void *", "pktinfo_t *",
+    "struct tcpcb *", "csinfo_t *",
+    "uint8_t *", "ipinfo_t *",
+    "struct tcpcb *", "tcpsinfo_t *" ,
+    "struct tcphdr *", "tcpinfo_t *");
+
+SDT_PROBE_DEFINE5_XLATE(tcp, , , connect_established, connect-established,
+    "void *", "pktinfo_t *",
+    "struct tcpcb *", "csinfo_t *",
+    "uint8_t *", "ipinfo_t *",
+    "struct tcpcb *", "tcpsinfo_t *" ,
+    "struct tcphdr *", "tcpinfo_t *");
+
+SDT_PROBE_DEFINE5_XLATE(tcp, , , connect_refused, connect-refused,
+    "void *", "pktinfo_t *",
+    "struct tcpcb *", "csinfo_t *",
+    "uint8_t *", "ipinfo_t *",
+    "struct tcpcb *", "tcpsinfo_t *" ,
+    "struct tcphdr *", "tcpinfo_t *");
+
+SDT_PROBE_DEFINE5_XLATE(tcp, , , connect_request, connect-request,
+    "void *", "pktinfo_t *",
+    "struct tcpcb *", "csinfo_t *",
+    "uint8_t *", "ipinfo_t *",
+    "struct tcpcb *", "tcpsinfo_t *" ,
+    "struct tcphdr *", "tcpinfo_t *");
+
+SDT_PROBE_DEFINE5_XLATE(tcp, , , receive, receive,
+    "void *", "pktinfo_t *",
+    "struct tcpcb *", "csinfo_t *",
+    "uint8_t *", "ipinfo_t *",
+    "struct tcpcb *", "tcpsinfo_t *" ,
+    "struct tcphdr *", "tcpinfo_t *");
+
+SDT_PROBE_DEFINE5_XLATE(tcp, , , send, send,
+    "void *", "pktinfo_t *",
+    "struct tcpcb *", "csinfo_t *",
+    "uint8_t *", "ipinfo_t *",
+    "struct tcpcb *", "tcpsinfo_t *" ,
+    "struct tcphdr *", "tcpinfo_t *");
+
+SDT_PROBE_DEFINE6_XLATE(tcp, , , state_change, state-change,
+    "void *", "void *",
+    "struct tcpcb *", "csinfo_t *",
+    "void *", "void *",
+    "struct tcpcb *", "tcpsinfo_t *",
+    "void *", "void *",
+    "int", "tcplsinfo_t *");
+
+SDT_PROBE_DEFINE5_XLATE(udp, , , receive, receive,
+    "void *", "pktinfo_t *",
+    "struct inpcb *", "csinfo_t *",
+    "uint8_t *", "ipinfo_t *",
+    "struct inpcb *", "udpsinfo_t *",
+    "struct udphdr *", "udpinfo_t *");
+
+SDT_PROBE_DEFINE5_XLATE(udp, , , send, send,
+    "void *", "pktinfo_t *",
+    "struct inpcb *", "csinfo_t *",
+    "uint8_t *", "ipinfo_t *",
+    "struct inpcb *", "udpsinfo_t *",
+    "struct udphdr *", "udpinfo_t *");
diff --git a/sys/netinet/in_kdtrace.h b/sys/netinet/in_kdtrace.h
new file mode 100644
index 0000000..2afecfa
--- /dev/null
+++ b/sys/netinet/in_kdtrace.h
@@ -0,0 +1,50 @@
+/*-
+ * Copyright (c) 2013 Mark Johnston <markj@FreeBSD.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _SYS_IN_KDTRACE_H_
+#define	_SYS_IN_KDTRACE_H_
+
+SDT_PROVIDER_DECLARE(ip);
+SDT_PROVIDER_DECLARE(tcp);
+SDT_PROVIDER_DECLARE(udp);
+
+SDT_PROBE_DECLARE(ip, , , receive);
+SDT_PROBE_DECLARE(ip, , , send);
+
+SDT_PROBE_DECLARE(tcp, , , accept_established);
+SDT_PROBE_DECLARE(tcp, , , accept_refused);
+SDT_PROBE_DECLARE(tcp, , , connect_established);
+SDT_PROBE_DECLARE(tcp, , , connect_refused);
+SDT_PROBE_DECLARE(tcp, , , connect_request);
+SDT_PROBE_DECLARE(tcp, , , receive);
+SDT_PROBE_DECLARE(tcp, , , send);
+SDT_PROBE_DECLARE(tcp, , , state_change);
+
+SDT_PROBE_DECLARE(udp, , , receive);
+SDT_PROBE_DECLARE(udp, , , send);
+
+#endif
diff --git a/sys/netinet/ip_fastfwd.c b/sys/netinet/ip_fastfwd.c
index 989318e..9a5cc92 100644
--- a/sys/netinet/ip_fastfwd.c
+++ b/sys/netinet/ip_fastfwd.c
@@ -78,6 +78,7 @@ __FBSDID("$FreeBSD$");
 
 #include "opt_ipfw.h"
 #include "opt_ipstealth.h"
+#include "opt_kdtrace.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -85,6 +86,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/malloc.h>
 #include <sys/mbuf.h>
 #include <sys/protosw.h>
+#include <sys/sdt.h>
 #include <sys/socket.h>
 #include <sys/sysctl.h>
 
@@ -97,6 +99,7 @@ __FBSDID("$FreeBSD$");
 #include <net/vnet.h>
 
 #include <netinet/in.h>
+#include <netinet/in_kdtrace.h>
 #include <netinet/in_systm.h>
 #include <netinet/in_var.h>
 #include <netinet/ip.h>
@@ -531,6 +534,7 @@ passout:
 		/*
 		 * Send off the packet via outgoing interface
 		 */
+		SDT_PROBE6(ip, , , send, NULL, NULL, ip, ifp, ip, NULL);
 		error = (*ifp->if_output)(ifp, m,
 				(struct sockaddr *)dst, &ro);
 	} else {
@@ -562,6 +566,8 @@ passout:
 				 */
 				m_clrprotoflags(m);
 
+				SDT_PROBE6(ip, , , send, NULL, NULL, ip, ifp,
+				    ip, NULL);
 				error = (*ifp->if_output)(ifp, m,
 					(struct sockaddr *)dst, &ro);
 				if (error)
diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index 2d84f28..d2f04f3 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$");
 #include "opt_ipfw.h"
 #include "opt_ipstealth.h"
 #include "opt_ipsec.h"
+#include "opt_kdtrace.h"
 #include "opt_route.h"
 
 #include <sys/param.h>
@@ -49,6 +50,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/kernel.h>
 #include <sys/lock.h>
 #include <sys/rwlock.h>
+#include <sys/sdt.h>
 #include <sys/syslog.h>
 #include <sys/sysctl.h>
 
@@ -63,6 +65,7 @@ __FBSDID("$FreeBSD$");
 #include <net/flowtable.h>
 
 #include <netinet/in.h>
+#include <netinet/in_kdtrace.h>
 #include <netinet/in_systm.h>
 #include <netinet/in_var.h>
 #include <netinet/ip.h>
@@ -429,6 +432,9 @@ ip_input(struct mbuf *m)
 		ip = mtod(m, struct ip *);
 	}
 
+	SDT_PROBE6(ip, , , receive, NULL, NULL, ip, m->m_pkthdr.rcvif, ip,
+	    NULL);
+
 	/* 127/8 must not appear on wire - RFC1122 */
 	ifp = m->m_pkthdr.rcvif;
 	if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index 0a87e7a..15196e0 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -34,9 +34,10 @@ __FBSDID("$FreeBSD$");
 
 #include "opt_ipfw.h"
 #include "opt_ipsec.h"
-#include "opt_route.h"
+#include "opt_kdtrace.h"
 #include "opt_mbuf_stress_test.h"
 #include "opt_mpath.h"
+#include "opt_route.h"
 #include "opt_sctp.h"
 
 #include <sys/param.h>
@@ -47,6 +48,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/priv.h>
 #include <sys/proc.h>
 #include <sys/protosw.h>
+#include <sys/sdt.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
 #include <sys/sysctl.h>
@@ -64,6 +66,7 @@ __FBSDID("$FreeBSD$");
 #include <net/vnet.h>
 
 #include <netinet/in.h>
+#include <netinet/in_kdtrace.h>
 #include <netinet/in_systm.h>
 #include <netinet/ip.h>
 #include <netinet/in_pcb.h>
@@ -622,6 +625,7 @@ passout:
 		 * to avoid confusing lower layers.
 		 */
 		m_clrprotoflags(m);
+		SDT_PROBE6(ip, , , send, NULL, NULL, ip, ifp, ip, NULL);
 		error = (*ifp->if_output)(ifp, m,
 		    (const struct sockaddr *)gw, ro);
 		goto done;
@@ -656,6 +660,7 @@ passout:
 			 */
 			m_clrprotoflags(m);
 
+			SDT_PROBE6(ip, , , send, NULL, NULL, ip, ifp, ip, NULL);
 			error = (*ifp->if_output)(ifp, m,
 			    (const struct sockaddr *)gw, ro);
 		} else
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index 99bbbd3..90ce3ba 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -54,6 +54,7 @@ __FBSDID("$FreeBSD$");
 #include "opt_inet.h"
 #include "opt_inet6.h"
 #include "opt_ipsec.h"
+#include "opt_kdtrace.h"
 #include "opt_tcpdebug.h"
 
 #include <sys/param.h>
@@ -63,6 +64,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/mbuf.h>
 #include <sys/proc.h>		/* for proc0 declaration */
 #include <sys/protosw.h>
+#include <sys/sdt.h>
 #include <sys/signalvar.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
@@ -82,6 +84,7 @@ __FBSDID("$FreeBSD$");
 
 #include <netinet/cc.h>
 #include <netinet/in.h>
+#include <netinet/in_kdtrace.h>
 #include <netinet/in_pcb.h>
 #include <netinet/in_systm.h>
 #include <netinet/in_var.h>
@@ -688,7 +691,10 @@ tcp_input(struct mbuf *m, int off0)
 			bzero(ipov->ih_x1, sizeof(ipov->ih_x1));
 			ipov->ih_len = htons(tlen);
 			th->th_sum = in_cksum(m, len);
+			/* Reset length for SDT probes. */
+			ip->ip_len = htons(tlen + off0);
 		}
+
 		if (th->th_sum) {
 			TCPSTAT_INC(tcps_rcvbadsum);
 			goto drop;
@@ -1384,6 +1390,8 @@ relocked:
 	}
 #endif
 
+	SDT_PROBE5(tcp, , , receive, NULL, tp, m->m_data, tp, th);
+
 	/*
 	 * Segment belongs to a connection in SYN_SENT, ESTABLISHED or later
 	 * state.  tcp_do_segment() always consumes the mbuf chain, unlocks
@@ -1394,6 +1402,8 @@ relocked:
 	return;
 
 dropwithreset:
+	SDT_PROBE5(tcp, , , receive, NULL, tp, m->m_data, tp, th);
+
 	if (ti_locked == TI_WLOCKED) {
 		INP_INFO_WUNLOCK(&V_tcbinfo);
 		ti_locked = TI_UNLOCKED;
@@ -1415,6 +1425,9 @@ dropwithreset:
 	goto drop;
 
 dropunlock:
+	if (m != NULL)
+		SDT_PROBE5(tcp, , , receive, NULL, tp, m->m_data, tp, th);
+
 	if (ti_locked == TI_WLOCKED) {
 		INP_INFO_WUNLOCK(&V_tcbinfo);
 		ti_locked = TI_UNLOCKED;
@@ -1910,8 +1923,11 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
 			rstreason = BANDLIM_UNLIMITED;
 			goto dropwithreset;
 		}
-		if ((thflags & (TH_ACK|TH_RST)) == (TH_ACK|TH_RST))
+		if ((thflags & (TH_ACK|TH_RST)) == (TH_ACK|TH_RST)) {
+			SDT_PROBE5(tcp, , , connect_refused, NULL, tp,
+			    m->m_data, tp, th);
 			tp = tcp_drop(tp, ECONNREFUSED);
+		}
 		if (thflags & TH_RST)
 			goto drop;
 		if (!(thflags & TH_SYN))
@@ -1956,11 +1972,13 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
 			 */
 			tp->t_starttime = ticks;
 			if (tp->t_flags & TF_NEEDFIN) {
-				tp->t_state = TCPS_FIN_WAIT_1;
+				tcp_state_change(tp, TCPS_FIN_WAIT_1);
 				tp->t_flags &= ~TF_NEEDFIN;
 				thflags &= ~TH_SYN;
 			} else {
-				tp->t_state = TCPS_ESTABLISHED;
+				tcp_state_change(tp, TCPS_ESTABLISHED);
+				SDT_PROBE5(tcp, , , connect_established, NULL,
+				    tp, m->m_data, tp, th);
 				cc_conn_init(tp);
 				tcp_timer_activate(tp, TT_KEEP,
 				    TP_KEEPIDLE(tp));
@@ -1978,7 +1996,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
 			 */
 			tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
 			tcp_timer_activate(tp, TT_REXMT, 0);
-			tp->t_state = TCPS_SYN_RECEIVED;
+			tcp_state_change(tp, TCPS_SYN_RECEIVED);
 		}
 
 		KASSERT(ti_locked == TI_WLOCKED, ("%s: trimthenstep6: "
@@ -2116,7 +2134,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
 				    ti_locked));
 				INP_INFO_WLOCK_ASSERT(&V_tcbinfo);
 
-				tp->t_state = TCPS_CLOSED;
+				tcp_state_change(tp, TCPS_CLOSED);
 				TCPSTAT_INC(tcps_drops);
 				tp = tcp_close(tp);
 				break;
@@ -2361,10 +2379,12 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
 		 */
 		tp->t_starttime = ticks;
 		if (tp->t_flags & TF_NEEDFIN) {
-			tp->t_state = TCPS_FIN_WAIT_1;
+			tcp_state_change(tp, TCPS_FIN_WAIT_1);
 			tp->t_flags &= ~TF_NEEDFIN;
 		} else {
-			tp->t_state = TCPS_ESTABLISHED;
+			tcp_state_change(tp, TCPS_ESTABLISHED);
+			SDT_PROBE5(tcp, , , accept_established, NULL, tp,
+			    m->m_data, tp, th);
 			cc_conn_init(tp);
 			tcp_timer_activate(tp, TT_KEEP, TP_KEEPIDLE(tp));
 		}
@@ -2752,7 +2772,7 @@ process_ACK:
 					    tcp_finwait2_timeout :
 					    TP_MAXIDLE(tp)));
 				}
-				tp->t_state = TCPS_FIN_WAIT_2;
+				tcp_state_change(tp, TCPS_FIN_WAIT_2);
 			}
 			break;
 
@@ -2978,7 +2998,7 @@ dodata:							/* XXX */
 			tp->t_starttime = ticks;
 			/* FALLTHROUGH */
 		case TCPS_ESTABLISHED:
-			tp->t_state = TCPS_CLOSE_WAIT;
+			tcp_state_change(tp, TCPS_CLOSE_WAIT);
 			break;
 
 		/*
@@ -2986,7 +3006,7 @@ dodata:							/* XXX */
 		 * enter the CLOSING state.
 		 */
 		case TCPS_FIN_WAIT_1:
-			tp->t_state = TCPS_CLOSING;
+			tcp_state_change(tp, TCPS_CLOSING);
 			break;
 
 		/*
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
index b4342f3..2a83b8e 100644
--- a/sys/netinet/tcp_output.c
+++ b/sys/netinet/tcp_output.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 #include "opt_inet.h"
 #include "opt_inet6.h"
 #include "opt_ipsec.h"
+#include "opt_kdtrace.h"
 #include "opt_tcpdebug.h"
 
 #include <sys/param.h>
@@ -46,6 +47,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/mbuf.h>
 #include <sys/mutex.h>
 #include <sys/protosw.h>
+#include <sys/sdt.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
 #include <sys/sysctl.h>
@@ -56,6 +58,7 @@ __FBSDID("$FreeBSD$");
 
 #include <netinet/cc.h>
 #include <netinet/in.h>
+#include <netinet/in_kdtrace.h>
 #include <netinet/in_systm.h>
 #include <netinet/ip.h>
 #include <netinet/in_pcb.h>
@@ -1174,6 +1177,20 @@ send:
 		 */
 		ip6->ip6_hlim = in6_selecthlim(tp->t_inpcb, NULL);
 
+		/*
+		 * Set the packet size here for the benefit of DTrace probes;
+		 * it will be incorrect since it doesn't include the option
+		 * headers, but there's no way to get the payload size
+		 * otherwise.
+		 */
+		ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(*ip6));
+
+		if (tp->t_state == TCPS_SYN_SENT)
+			SDT_PROBE5(tcp, , , connect_request, NULL, tp, ip6, tp,
+			    th);
+
+		SDT_PROBE5(tcp, , , send, NULL, tp, ip6, tp, th);
+
 		/* TODO: IPv6 IP6TOS_ECT bit on */
 		error = ip6_output(m, tp->t_inpcb->in6p_outputopts, &ro,
 		    ((so->so_options & SO_DONTROUTE) ?  IP_ROUTETOIF : 0),
@@ -1208,6 +1225,11 @@ send:
 	if (V_path_mtu_discovery && tp->t_maxopd > V_tcp_minmss)
 		ip->ip_off |= htons(IP_DF);
 
+	if (tp->t_state == TCPS_SYN_SENT)
+		SDT_PROBE5(tcp, , , connect_request, NULL, tp, ip, tp, th);
+
+	SDT_PROBE5(tcp, , , send, NULL, tp, ip, tp, th);
+
 	error = ip_output(m, tp->t_inpcb->inp_options, &ro,
 	    ((so->so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0), 0,
 	    tp->t_inpcb);
diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
index c466bf4..3c57f3d 100644
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$");
 #include "opt_inet.h"
 #include "opt_inet6.h"
 #include "opt_ipsec.h"
+#include "opt_kdtrace.h"
 #include "opt_tcpdebug.h"
 
 #include <sys/param.h>
@@ -53,6 +54,7 @@ __FBSDID("$FreeBSD$");
 #endif
 #include <sys/priv.h>
 #include <sys/proc.h>
+#include <sys/sdt.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
 #include <sys/protosw.h>
@@ -66,6 +68,7 @@ __FBSDID("$FreeBSD$");
 
 #include <netinet/cc.h>
 #include <netinet/in.h>
+#include <netinet/in_kdtrace.h>
 #include <netinet/in_pcb.h>
 #include <netinet/in_systm.h>
 #include <netinet/in_var.h>
@@ -632,8 +635,9 @@ tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
 		ip6->ip6_flow = 0;
 		ip6->ip6_vfc = IPV6_VERSION;
 		ip6->ip6_nxt = IPPROTO_TCP;
-		ip6->ip6_plen = 0;		/* Set in ip6_output(). */
 		tlen += sizeof (struct ip6_hdr) + sizeof (struct tcphdr);
+		/* This is for DTrace; it excludes option headers. */
+		ip6->ip6_plen = htons(tlen - sizeof(*ip6));
 	}
 #endif
 #if defined(INET) && defined(INET6)
@@ -702,6 +706,11 @@ tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
 	if (tp == NULL || (inp->inp_socket->so_options & SO_DEBUG))
 		tcp_trace(TA_OUTPUT, 0, tp, mtod(m, void *), th, 0);
 #endif
+	if (flags & TH_RST)
+		SDT_PROBE5(tcp, , , accept_refused, NULL, NULL, m->m_data, tp,
+		    nth);
+
+	SDT_PROBE5(tcp, , , send, NULL, tp, m->m_data, tp, nth);
 #ifdef INET6
 	if (isipv6)
 		(void) ip6_output(m, NULL, NULL, ipflags, NULL, NULL, inp);
@@ -882,7 +891,7 @@ tcp_drop(struct tcpcb *tp, int errno)
 	INP_WLOCK_ASSERT(tp->t_inpcb);
 
 	if (TCPS_HAVERCVDSYN(tp->t_state)) {
-		tp->t_state = TCPS_CLOSED;
+		tcp_state_change(tp, TCPS_CLOSED);
 		(void) tcp_output(tp);
 		TCPSTAT_INC(tcps_drops);
 	} else
@@ -2376,3 +2385,19 @@ tcp_log_addr(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
 		panic("%s: string too long", __func__);
 	return (s);
 }
+
+/*
+ * A subroutine which makes it easy to track TCP state changes with DTrace.
+ * This function shouldn't be called for t_state initializations that don't
+ * correspond to actual TCP state transitions.
+ */
+void
+tcp_state_change(struct tcpcb *tp, int newstate)
+{
+#if defined(KDTRACE_HOOKS)
+	int pstate = tp->t_state;
+#endif
+
+	tp->t_state = newstate;
+	SDT_PROBE6(tcp, , , state_change, NULL, tp, NULL, tp, NULL, pstate);
+}
diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c
index cd7b424..1c27d7a 100644
--- a/sys/netinet/tcp_syncache.c
+++ b/sys/netinet/tcp_syncache.c
@@ -835,7 +835,7 @@ syncache_socket(struct syncache *sc, struct socket *lso, struct mbuf *m)
 #endif /* INET */
 	INP_HASH_WUNLOCK(&V_tcbinfo);
 	tp = intotcpcb(inp);
-	tp->t_state = TCPS_SYN_RECEIVED;
+	tcp_state_change(tp, TCPS_SYN_RECEIVED);
 	tp->iss = sc->sc_iss;
 	tp->irs = sc->sc_irs;
 	tcp_rcvseqinit(tp);
diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c
index ef0aad1..88755e7 100644
--- a/sys/netinet/tcp_usrreq.c
+++ b/sys/netinet/tcp_usrreq.c
@@ -367,7 +367,7 @@ tcp_usr_listen(struct socket *so, int backlog, struct thread *td)
 		error = in_pcbbind(inp, (struct sockaddr *)0, td->td_ucred);
 	INP_HASH_WUNLOCK(&V_tcbinfo);
 	if (error == 0) {
-		tp->t_state = TCPS_LISTEN;
+		tcp_state_change(tp, TCPS_LISTEN);
 		solisten_proto(so, backlog);
 #ifdef TCP_OFFLOAD
 		if ((so->so_options & SO_NO_OFFLOAD) == 0)
@@ -412,7 +412,7 @@ tcp6_usr_listen(struct socket *so, int backlog, struct thread *td)
 	}
 	INP_HASH_WUNLOCK(&V_tcbinfo);
 	if (error == 0) {
-		tp->t_state = TCPS_LISTEN;
+		tcp_state_change(tp, TCPS_LISTEN);
 		solisten_proto(so, backlog);
 #ifdef TCP_OFFLOAD
 		if ((so->so_options & SO_NO_OFFLOAD) == 0)
@@ -1152,7 +1152,7 @@ tcp_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
 
 	soisconnecting(so);
 	TCPSTAT_INC(tcps_connattempt);
-	tp->t_state = TCPS_SYN_SENT;
+	tcp_state_change(tp, TCPS_SYN_SENT);
 	tp->iss = tcp_new_isn(tp);
 	tcp_sendseqinit(tp);
 
@@ -1224,7 +1224,7 @@ tcp6_connect(struct tcpcb *tp, struct sockaddr *nam, struct thread *td)
 
 	soisconnecting(so);
 	TCPSTAT_INC(tcps_connattempt);
-	tp->t_state = TCPS_SYN_SENT;
+	tcp_state_change(tp, TCPS_SYN_SENT);
 	tp->iss = tcp_new_isn(tp);
 	tcp_sendseqinit(tp);
 
@@ -1704,7 +1704,7 @@ tcp_usrclosed(struct tcpcb *tp)
 #endif
 		/* FALLTHROUGH */
 	case TCPS_CLOSED:
-		tp->t_state = TCPS_CLOSED;
+		tcp_state_change(tp, TCPS_CLOSED);
 		tp = tcp_close(tp);
 		/*
 		 * tcp_close() should never return NULL here as the socket is
@@ -1720,11 +1720,11 @@ tcp_usrclosed(struct tcpcb *tp)
 		break;
 
 	case TCPS_ESTABLISHED:
-		tp->t_state = TCPS_FIN_WAIT_1;
+		tcp_state_change(tp, TCPS_FIN_WAIT_1);
 		break;
 
 	case TCPS_CLOSE_WAIT:
-		tp->t_state = TCPS_LAST_ACK;
+		tcp_state_change(tp, TCPS_LAST_ACK);
 		break;
 	}
 	if (tp->t_state >= TCPS_FIN_WAIT_2) {
diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
index cfba5d9..b22713f 100644
--- a/sys/netinet/tcp_var.h
+++ b/sys/netinet/tcp_var.h
@@ -701,6 +701,7 @@ struct inpcb *
 struct tcpcb *
 	 tcp_newtcpcb(struct inpcb *);
 int	 tcp_output(struct tcpcb *);
+void	 tcp_state_change(struct tcpcb *, int);
 void	 tcp_respond(struct tcpcb *, void *,
 	    struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, int);
 void	 tcp_tw_init(void);
diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c
index afd11e6..e38e288 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>
@@ -68,6 +70,7 @@ __FBSDID("$FreeBSD$");
 #include <net/route.h>
 
 #include <netinet/in.h>
+#include <netinet/in_kdtrace.h>
 #include <netinet/in_pcb.h>
 #include <netinet/in_systm.h>
 #include <netinet/in_var.h>
@@ -616,6 +619,8 @@ udp_input(struct mbuf *m, int off)
 		m_freem(m);
 		return;
 	}
+
+	SDT_PROBE5(udp, , , receive, NULL, inp, ip, ip, uh);
 	udp_append(inp, ip, m, iphlen, &udp_in);
 	INP_RUNLOCK(inp);
 	return;
@@ -1193,6 +1198,7 @@ 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;
@@ -1243,6 +1249,7 @@ 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, NULL, inp, &ui->ui_i, 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 0c26b88..461c986 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/ip6_input.c b/sys/netinet6/ip6_input.c
index 02bbf75..e534921 100644
--- a/sys/netinet6/ip6_input.c
+++ b/sys/netinet6/ip6_input.c
@@ -67,6 +67,7 @@ __FBSDID("$FreeBSD$");
 #include "opt_inet6.h"
 #include "opt_ipfw.h"
 #include "opt_ipsec.h"
+#include "opt_kdtrace.h"
 #include "opt_route.h"
 
 #include <sys/param.h>
@@ -76,6 +77,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/proc.h>
 #include <sys/domain.h>
 #include <sys/protosw.h>
+#include <sys/sdt.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
 #include <sys/errno.h>
@@ -92,6 +94,7 @@ __FBSDID("$FreeBSD$");
 #include <net/vnet.h>
 
 #include <netinet/in.h>
+#include <netinet/in_kdtrace.h>
 #include <netinet/ip_var.h>
 #include <netinet/in_systm.h>
 #include <net/if_llatbl.h>
@@ -538,6 +541,9 @@ ip6_input(struct mbuf *m)
 
 	IP6STAT_INC(ip6s_nxthist[ip6->ip6_nxt]);
 
+	SDT_PROBE6(ip, , , receive, NULL, NULL, ip6, m->m_pkthdr.rcvif, NULL,
+	    ip6);
+
 	/*
 	 * Check against address spoofing/corruption.
 	 */
diff --git a/sys/netinet6/ip6_mroute.c b/sys/netinet6/ip6_mroute.c
index 40c8c44..6ccb4b5 100644
--- a/sys/netinet6/ip6_mroute.c
+++ b/sys/netinet6/ip6_mroute.c
@@ -82,6 +82,7 @@
 __FBSDID("$FreeBSD$");
 
 #include "opt_inet6.h"
+#include "opt_kdtrace.h"
 
 #include <sys/param.h>
 #include <sys/callout.h>
@@ -93,6 +94,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/module.h>
 #include <sys/domain.h>
 #include <sys/protosw.h>
+#include <sys/sdt.h>
 #include <sys/signalvar.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
@@ -114,6 +116,7 @@ __FBSDID("$FreeBSD$");
 #include <netinet/ip_encap.h>
 
 #include <netinet/ip6.h>
+#include <netinet/in_kdtrace.h>
 #include <netinet6/ip6_var.h>
 #include <netinet6/scope6_var.h>
 #include <netinet6/nd6.h>
@@ -1644,6 +1647,8 @@ phyint_send(struct ip6_hdr *ip6, struct mif6 *mifp, struct mbuf *m)
 		dst6.sin6_len = sizeof(struct sockaddr_in6);
 		dst6.sin6_family = AF_INET6;
 		dst6.sin6_addr = ip6->ip6_dst;
+
+		SDT_PROBE6(ip, , , send, NULL, NULL, ip6, ifp, NULL, ip6);
 		/*
 		 * We just call if_output instead of nd6_output here, since
 		 * we need no ND for a multicast forwarded packet...right?
diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c
index 7755da1..9eaa0aa 100644
--- a/sys/netinet6/nd6.c
+++ b/sys/netinet6/nd6.c
@@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$");
 
 #include "opt_inet.h"
 #include "opt_inet6.h"
+#include "opt_kdtrace.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -50,6 +51,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/lock.h>
 #include <sys/rwlock.h>
 #include <sys/queue.h>
+#include <sys/sdt.h>
 #include <sys/sysctl.h>
 
 #include <net/if.h>
@@ -62,6 +64,7 @@ __FBSDID("$FreeBSD$");
 #include <net/vnet.h>
 
 #include <netinet/in.h>
+#include <netinet/in_kdtrace.h>
 #include <net/if_llatbl.h>
 #define	L3_ADDR_SIN6(le)	((struct sockaddr_in6 *) L3_ADDR(le))
 #include <netinet/if_ether.h>
@@ -2083,6 +2086,8 @@ nd6_output_lle(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
 		return (error);
 	}
 	m_clrprotoflags(m);	/* Avoid confusing lower layers. */
+	SDT_PROBE6(ip, , , send, NULL, NULL, mtod(m, struct ip6_hdr *), ifp,
+	    NULL, mtod(m, struct ip6_hdr *));
 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
 		return ((*ifp->if_output)(origifp, m, (struct sockaddr *)dst,
 		    NULL));
diff --git a/sys/netinet6/send.c b/sys/netinet6/send.c
index 233abdb..7d4bd2c 100644
--- a/sys/netinet6/send.c
+++ b/sys/netinet6/send.c
@@ -27,12 +27,15 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include "opt_kdtrace.h"
+
 #include <sys/param.h>
 #include <sys/kernel.h>
 #include <sys/mbuf.h>
 #include <sys/module.h>
 #include <sys/priv.h>
 #include <sys/protosw.h>
+#include <sys/sdt.h>
 #include <sys/systm.h>
 #include <sys/socket.h>
 #include <sys/sockstate.h>
@@ -46,6 +49,7 @@ __FBSDID("$FreeBSD$");
 #include <net/vnet.h>
 
 #include <netinet/in.h>
+#include <netinet/in_kdtrace.h>
 #include <netinet/ip_var.h>
 #include <netinet/ip6.h>
 #include <netinet/icmp6.h>
@@ -182,6 +186,8 @@ send_output(struct mbuf *m, struct ifnet *ifp, int direction)
 
 		m_clrprotoflags(m);	/* Avoid confusing lower layers. */
 
+		SDT_PROBE6(ip, , , send, NULL, NULL, ip6, ifp, NULL, ip6);
+
 		/*
 		 * Output the packet as nd6.c:nd6_output_lle() would do.
 		 * The mbuf is always consumed, so we do not have to care
diff --git a/sys/netinet6/udp6_usrreq.c b/sys/netinet6/udp6_usrreq.c
index 6aadae1..1b3990a 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>
@@ -95,6 +97,7 @@ __FBSDID("$FreeBSD$");
 #include <net/route.h>
 
 #include <netinet/in.h>
+#include <netinet/in_kdtrace.h>
 #include <netinet/in_pcb.h>
 #include <netinet/in_systm.h>
 #include <netinet/in_var.h>
@@ -377,6 +380,7 @@ udp6_input(struct mbuf **mp, int *offp, int proto)
 		INP_RLOCK(last);
 		INP_INFO_RUNLOCK(&V_udbinfo);
 		up = intoudpcb(last);
+		SDT_PROBE5(udp, , , receive, NULL, last, ip6, last, uh);
 		if (up->u_tun_func == NULL) {
 			udp6_append(last, m, off, &fromsa);
 		} else {
@@ -455,6 +459,7 @@ udp6_input(struct mbuf **mp, int *offp, int proto)
 	}
 	INP_RLOCK_ASSERT(inp);
 	up = intoudpcb(inp);
+	SDT_PROBE5(udp, , , receive, NULL, inp, ip6, inp, uh);
 	if (up->u_tun_func == NULL) {
 		udp6_append(inp, m, off, &fromsa);
 	} else {
@@ -771,9 +776,7 @@ udp6_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr6,
 		ip6->ip6_flow	= inp->inp_flow & IPV6_FLOWINFO_MASK;
 		ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
 		ip6->ip6_vfc	|= IPV6_VERSION;
-#if 0				/* ip6_plen will be filled in ip6_output. */
 		ip6->ip6_plen	= htons((u_short)plen);
-#endif
 		ip6->ip6_nxt	= IPPROTO_UDP;
 		ip6->ip6_hlim	= in6_selecthlim(inp, NULL);
 		ip6->ip6_src	= *laddr;
@@ -785,6 +788,7 @@ udp6_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr6,
 
 		flags = 0;
 
+		SDT_PROBE5(udp, , , send, NULL, inp, ip6, inp, udp6);
 		UDPSTAT_INC(udps_opackets);
 		error = ip6_output(m, optp, NULL, flags, inp->in6p_moptions,
 		    NULL, inp);