zebra: add pseudowire manager

Base framework for supporting MPLS pseudowires in FRR.

A consistent zserv interface is provided so that any client daemon
(e.g. ldpd, bgpd) can install/uninstall pseudowires in a standard
way. Static pseudowires can also be implemented by using the same
interface.

When zebra receives a request to install a pseudowire and the installation
in the kernel or hardware fails, a notification is sent back to the
client daemon and a new install attempt is made every 60 seconds (until
it succeeds).

Support for external dataplanes is provided by the use of hooks to
install/uninstall pseudowires.

Signed-off-by: ßingen <bingen@voltanet.io>
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

16 files changed, 655 insertions, 3 deletions

diff --git a/ldpd/ldp.h b/ldpd/ldp.h
index c2b64d20c..cac3da7c5 100644
--- a/ldpd/ldp.h
+++ b/ldpd/ldp.h
@@ -285,9 +285,6 @@ struct address_list_tlv {
 #define	MAP_TYPE_GENPWID	0x81
 
 #define CONTROL_WORD_FLAG	0x8000
-#define PW_TYPE_ETHERNET_TAGGED	0x0004
-#define PW_TYPE_ETHERNET	0x0005
-#define PW_TYPE_WILDCARD	0x7FFF
 #define DEFAULT_PW_TYPE		PW_TYPE_ETHERNET
 
 #define PW_TWCARD_RESERVED_BIT	0x8000
diff --git a/ldpd/ldpd.h b/ldpd/ldpd.h
index 00d2627f1..c09f62e63 100644
--- a/ldpd/ldpd.h
+++ b/ldpd/ldpd.h
@@ -30,6 +30,7 @@
 #include "prefix.h"
 #include "filter.h"
 #include "vty.h"
+#include "pw.h"
 
 #include "ldp.h"
 
diff --git a/lib/log.c b/lib/log.c
index 5adb06d28..63afbf513 100644
--- a/lib/log.c
+++ b/lib/log.c
@@ -916,6 +916,11 @@ static const struct zebra_desc_table command_types[] = {
 	DESC_ENTRY(ZEBRA_MACIP_DEL),
 	DESC_ENTRY(ZEBRA_REMOTE_MACIP_ADD),
 	DESC_ENTRY(ZEBRA_REMOTE_MACIP_DEL),
+	DESC_ENTRY(ZEBRA_PW_ADD),
+	DESC_ENTRY(ZEBRA_PW_DELETE),
+	DESC_ENTRY(ZEBRA_PW_SET),
+	DESC_ENTRY(ZEBRA_PW_UNSET),
+	DESC_ENTRY(ZEBRA_PW_STATUS_UPDATE),
 };
 #undef DESC_ENTRY
 
diff --git a/lib/pw.h b/lib/pw.h
new file mode 100644
index 000000000..b34f681ac
--- /dev/null
+++ b/lib/pw.h
@@ -0,0 +1,47 @@
+/* Pseudowire definitions
+ * Copyright (C) 2016 Volta Networks, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#ifndef _FRR_PW_H
+#define _FRR_PW_H
+
+/* Pseudowire type - LDP and BGP use the same values. */
+#define PW_TYPE_ETHERNET_TAGGED	0x0004	/* RFC 4446 */
+#define PW_TYPE_ETHERNET	0x0005	/* RFC 4446 */
+#define PW_TYPE_WILDCARD	0x7FFF	/* RFC 4863, RFC 6668 */
+
+/* Pseudowire flags. */
+#define F_PSEUDOWIRE_CWORD	0x01
+
+/* Pseudowire status. */
+#define PW_STATUS_DOWN		0
+#define PW_STATUS_UP		1
+
+/*
+ * Protocol-specific information about the pseudowire.
+ */
+union pw_protocol_fields {
+	struct {
+		/* TODO */
+	} ldp;
+	struct {
+		/* TODO */
+	} bgp;
+};
+
+#endif /* _FRR_PW_H */
diff --git a/lib/subdir.am b/lib/subdir.am
index 28a4ce557..15ce8ec19 100644
--- a/lib/subdir.am
+++ b/lib/subdir.am
@@ -123,6 +123,7 @@ pkginclude_HEADERS += \
 	lib/prefix.h \
 	lib/privs.h \
 	lib/ptm_lib.h \
+	lib/pw.h \
 	lib/qobj.h \
 	lib/route_types.h \
 	lib/routemap.h \
diff --git a/lib/zclient.c b/lib/zclient.c
index a6252af40..893d769e3 100644
--- a/lib/zclient.c
+++ b/lib/zclient.c
@@ -1834,6 +1834,69 @@ int lm_release_label_chunk(struct zclient *zclient, uint32_t start,
 	return 0;
 }
 
+int zebra_send_pw(struct zclient *zclient, int command, struct zapi_pw *pw)
+{
+	struct stream *s;
+
+	/* Reset stream. */
+	s = zclient->obuf;
+	stream_reset(s);
+
+	zclient_create_header(s, command, VRF_DEFAULT);
+	stream_write(s, pw->ifname, IF_NAMESIZE);
+	stream_putl(s, pw->ifindex);
+
+	/* Put type */
+	stream_putl(s, pw->type);
+
+	/* Put nexthop */
+	stream_putl(s, pw->af);
+	switch (pw->af) {
+	case AF_INET:
+		stream_put_in_addr(s, &pw->nexthop.ipv4);
+		break;
+	case AF_INET6:
+		stream_write(s, (u_char *)&pw->nexthop.ipv6, 16);
+		break;
+	default:
+		zlog_err("%s: unknown af", __func__);
+		return -1;
+	}
+
+	/* Put labels */
+	stream_putl(s, pw->local_label);
+	stream_putl(s, pw->remote_label);
+
+	/* Put flags */
+	stream_putc(s, pw->flags);
+
+	/* Protocol specific fields */
+	stream_write(s, &pw->data, sizeof(union pw_protocol_fields));
+
+	/* Put length at the first point of the stream. */
+	stream_putw_at(s, 0, stream_get_endp(s));
+
+	return zclient_send_message(zclient);
+}
+
+/*
+ * Receive PW status update from Zebra and send it to LDE process.
+ */
+void zebra_read_pw_status_update(int command, struct zclient *zclient,
+				 zebra_size_t length, vrf_id_t vrf_id,
+				 struct zapi_pw_status *pw)
+{
+	struct stream *s;
+
+	memset(pw, 0, sizeof(struct zapi_pw_status));
+	s = zclient->ibuf;
+
+	/* Get data. */
+	stream_get(pw->ifname, s, IF_NAMESIZE);
+	pw->ifindex = stream_getl(s);
+	pw->status = stream_getl(s);
+}
+
 /* Zebra client message read function. */
 static int zclient_read(struct thread *thread)
 {
@@ -2061,6 +2124,11 @@ static int zclient_read(struct thread *thread)
 			(*zclient->local_macip_del)(command, zclient, length,
 						    vrf_id);
 		break;
+	case ZEBRA_PW_STATUS_UPDATE:
+		if (zclient->pw_status_update)
+			(*zclient->pw_status_update)(command, zclient, length,
+						     vrf_id);
+		break;
 	default:
 		break;
 	}
diff --git a/lib/zclient.h b/lib/zclient.h
index 435d26e2f..8a2729543 100644
--- a/lib/zclient.h
+++ b/lib/zclient.h
@@ -30,6 +30,12 @@
 /* For vrf_bitmap_t. */
 #include "vrf.h"
 
+/* For union g_addr */
+#include "nexthop.h"
+
+/* For union pw_protocol_fields */
+#include "pw.h"
+
 /* For input/output buffer to zebra. */
 #define ZEBRA_MAX_PACKET_SIZ          4096
 
@@ -106,6 +112,11 @@ typedef enum {
 	ZEBRA_MACIP_DEL,
 	ZEBRA_REMOTE_MACIP_ADD,
 	ZEBRA_REMOTE_MACIP_DEL,
+	ZEBRA_PW_ADD,
+	ZEBRA_PW_DELETE,
+	ZEBRA_PW_SET,
+	ZEBRA_PW_UNSET,
+	ZEBRA_PW_STATUS_UPDATE,
 } zebra_message_types_t;
 
 struct redist_proto {
@@ -187,6 +198,7 @@ struct zclient {
 	int (*local_vni_del)(int, struct zclient *, uint16_t, vrf_id_t);
 	int (*local_macip_add)(int, struct zclient *, uint16_t, vrf_id_t);
 	int (*local_macip_del)(int, struct zclient *, uint16_t, vrf_id_t);
+	int (*pw_status_update)(int, struct zclient *, uint16_t, vrf_id_t);
 };
 
 /* Zebra API message flag. */
@@ -266,6 +278,25 @@ struct zapi_ipv4 {
 	vrf_id_t vrf_id;
 };
 
+struct zapi_pw {
+	char ifname[IF_NAMESIZE];
+	ifindex_t ifindex;
+	int type;
+	int af;
+	union g_addr nexthop;
+	uint32_t local_label;
+	uint32_t remote_label;
+	uint8_t flags;
+	union pw_protocol_fields data;
+	uint8_t protocol;
+};
+
+struct zapi_pw_status {
+	char ifname[IF_NAMESIZE];
+	ifindex_t ifindex;
+	uint32_t status;
+};
+
 /* Prototypes of zebra client service functions. */
 extern struct zclient *zclient_new(struct thread_master *);
 extern void zclient_init(struct zclient *, int, u_short);
@@ -338,6 +369,12 @@ extern int lm_get_label_chunk(struct zclient *zclient, u_char keep,
 			      uint32_t *end);
 extern int lm_release_label_chunk(struct zclient *zclient, uint32_t start,
 				  uint32_t end);
+extern int zebra_send_pw(struct zclient *zclient, int command,
+			 struct zapi_pw *pw);
+extern void zebra_read_pw_status_update(int command, struct zclient *zclient,
+					zebra_size_t length, vrf_id_t vrf_id,
+					struct zapi_pw_status *pw);
+
 /* IPv6 prefix add and delete function prototype. */
 
 struct zapi_ipv6 {
diff --git a/zebra/debug.c b/zebra/debug.c
index 6aedea1e3..6728ed132 100644
--- a/zebra/debug.c
+++ b/zebra/debug.c
@@ -32,6 +32,7 @@ unsigned long zebra_debug_fpm;
 unsigned long zebra_debug_nht;
 unsigned long zebra_debug_mpls;
 unsigned long zebra_debug_vxlan;
+unsigned long zebra_debug_pw;
 
 DEFUN (show_debugging_zebra,
        show_debugging_zebra_cmd,
@@ -82,6 +83,8 @@ DEFUN (show_debugging_zebra,
 		vty_out(vty, "  Zebra next-hop tracking debugging is on\n");
 	if (IS_ZEBRA_DEBUG_MPLS)
 		vty_out(vty, "  Zebra MPLS debugging is on\n");
+	if (IS_ZEBRA_DEBUG_PW)
+		vty_out(vty, "  Zebra pseudowire debugging is on\n");
 
 	return CMD_SUCCESS;
 }
@@ -130,6 +133,21 @@ DEFUN (debug_zebra_vxlan,
 	return CMD_WARNING;
 }
 
+DEFUN (debug_zebra_pw,
+       debug_zebra_pw_cmd,
+       "[no] debug zebra pseudowires",
+       "Negate a command or set its defaults\n"
+       DEBUG_STR
+       "Zebra configuration\n"
+       "Debug option set for zebra pseudowires\n")
+{
+	if (strmatch(argv[0]->text, "no"))
+		UNSET_FLAG(zebra_debug_pw, ZEBRA_DEBUG_PW);
+	else
+		SET_FLAG(zebra_debug_pw, ZEBRA_DEBUG_PW);
+	return CMD_WARNING;
+}
+
 DEFUN (debug_zebra_packet,
        debug_zebra_packet_cmd,
        "debug zebra packet [<recv|send>] [detail]",
@@ -419,6 +437,10 @@ static int config_write_debug(struct vty *vty)
 		vty_out(vty, "debug zebra vxlan\n");
 		write++;
 	}
+	if (IS_ZEBRA_DEBUG_PW) {
+		vty_out(vty, "debug zebra pseudowires%s", VTY_NEWLINE);
+		write++;
+	}
 	return write;
 }
 
@@ -431,6 +453,7 @@ void zebra_debug_init(void)
 	zebra_debug_fpm = 0;
 	zebra_debug_mpls = 0;
 	zebra_debug_vxlan = 0;
+	zebra_debug_pw = 0;
 
 	install_node(&debug_node, config_write_debug);
 
@@ -440,6 +463,7 @@ void zebra_debug_init(void)
 	install_element(ENABLE_NODE, &debug_zebra_nht_cmd);
 	install_element(ENABLE_NODE, &debug_zebra_mpls_cmd);
 	install_element(ENABLE_NODE, &debug_zebra_vxlan_cmd);
+	install_element(ENABLE_NODE, &debug_zebra_pw_cmd);
 	install_element(ENABLE_NODE, &debug_zebra_packet_cmd);
 	install_element(ENABLE_NODE, &debug_zebra_kernel_cmd);
 	install_element(ENABLE_NODE, &debug_zebra_kernel_msgdump_cmd);
@@ -459,6 +483,7 @@ void zebra_debug_init(void)
 	install_element(CONFIG_NODE, &debug_zebra_nht_cmd);
 	install_element(CONFIG_NODE, &debug_zebra_mpls_cmd);
 	install_element(CONFIG_NODE, &debug_zebra_vxlan_cmd);
+	install_element(CONFIG_NODE, &debug_zebra_pw_cmd);
 	install_element(CONFIG_NODE, &debug_zebra_packet_cmd);
 	install_element(CONFIG_NODE, &debug_zebra_kernel_cmd);
 	install_element(CONFIG_NODE, &debug_zebra_kernel_msgdump_cmd);
diff --git a/zebra/debug.h b/zebra/debug.h
index b52bb7d0e..987f9d012 100644
--- a/zebra/debug.h
+++ b/zebra/debug.h
@@ -44,6 +44,8 @@
 
 #define ZEBRA_DEBUG_VXLAN   0x01
 
+#define ZEBRA_DEBUG_PW      0x01
+
 /* Debug related macro. */
 #define IS_ZEBRA_DEBUG_EVENT  (zebra_debug_event & ZEBRA_DEBUG_EVENT)
 
@@ -66,6 +68,7 @@
 #define IS_ZEBRA_DEBUG_NHT  (zebra_debug_nht & ZEBRA_DEBUG_NHT)
 #define IS_ZEBRA_DEBUG_MPLS  (zebra_debug_mpls & ZEBRA_DEBUG_MPLS)
 #define IS_ZEBRA_DEBUG_VXLAN (zebra_debug_vxlan & ZEBRA_DEBUG_VXLAN)
+#define IS_ZEBRA_DEBUG_PW  (zebra_debug_pw & ZEBRA_DEBUG_PW)
 
 extern unsigned long zebra_debug_event;
 extern unsigned long zebra_debug_packet;
@@ -75,6 +78,7 @@ extern unsigned long zebra_debug_fpm;
 extern unsigned long zebra_debug_nht;
 extern unsigned long zebra_debug_mpls;
 extern unsigned long zebra_debug_vxlan;
+extern unsigned long zebra_debug_pw;
 
 extern void zebra_debug_init(void);
 
diff --git a/zebra/subdir.am b/zebra/subdir.am
index ceffa863e..0391cab9f 100644
--- a/zebra/subdir.am
+++ b/zebra/subdir.am
@@ -56,6 +56,7 @@ zebra_zebra_SOURCES = \
 	zebra/zebra_ns.c \
 	zebra/zebra_ptm.c \
 	zebra/zebra_ptm_redistribute.c \
+	zebra/zebra_pw.c \
 	zebra/zebra_rib.c \
 	zebra/zebra_rnh.c \
 	zebra/zebra_routemap.c \
@@ -95,6 +96,7 @@ noinst_HEADERS += \
 	zebra/zebra_ns.h \
 	zebra/zebra_ptm.h \
 	zebra/zebra_ptm_redistribute.h \
+	zebra/zebra_pw.h \
 	zebra/zebra_rnh.h \
 	zebra/zebra_routemap.h \
 	zebra/zebra_static.h \
diff --git a/zebra/zebra_pw.c b/zebra/zebra_pw.c
new file mode 100644
index 000000000..143224254
--- /dev/null
+++ b/zebra/zebra_pw.c
@@ -0,0 +1,268 @@
+/* Zebra PW code
+ * Copyright (C) 2016 Volta Networks, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#include <zebra.h>
+
+#include "log.h"
+#include "memory.h"
+#include "thread.h"
+#include "vrf.h"
+
+#include "zebra/debug.h"
+#include "zebra/rib.h"
+#include "zebra/zserv.h"
+#include "zebra/zebra_vrf.h"
+#include "zebra/zebra_pw.h"
+
+DEFINE_MTYPE_STATIC(LIB, PW, "Pseudowire")
+
+DEFINE_HOOK(pw_install, (struct zebra_pw * pw), (pw))
+DEFINE_HOOK(pw_uninstall, (struct zebra_pw * pw), (pw))
+
+extern struct zebra_t zebrad;
+
+static void zebra_pw_install(struct zebra_pw *);
+static void zebra_pw_uninstall(struct zebra_pw *);
+static int zebra_pw_install_retry(struct thread *);
+static int zebra_pw_check_reachability(struct zebra_pw *);
+static void zebra_pw_update_status(struct zebra_pw *, int);
+
+static inline int zebra_pw_compare(const struct zebra_pw *a,
+				   const struct zebra_pw *b)
+{
+	return (strcmp(a->ifname, b->ifname));
+}
+
+RB_GENERATE(zebra_pw_head, zebra_pw, entry, zebra_pw_compare)
+
+struct zebra_pw *zebra_pw_add(struct zebra_vrf *zvrf, const char *ifname,
+			      uint8_t protocol, struct zserv *client)
+{
+	struct zebra_pw *pw;
+
+	if (IS_ZEBRA_DEBUG_PW)
+		zlog_debug("%u: adding pseudowire %s protocol %s",
+			   zvrf_id(zvrf), ifname, zebra_route_string(protocol));
+
+	pw = XCALLOC(MTYPE_PW, sizeof(*pw));
+	strlcpy(pw->ifname, ifname, sizeof(pw->ifname));
+	pw->protocol = protocol;
+	pw->vrf_id = zvrf_id(zvrf);
+	pw->client = client;
+	pw->status = PW_STATUS_UP;
+
+	RB_INSERT(zebra_pw_head, &zvrf->pseudowires, pw);
+
+	return pw;
+}
+
+void zebra_pw_del(struct zebra_vrf *zvrf, struct zebra_pw *pw)
+{
+	if (IS_ZEBRA_DEBUG_PW)
+		zlog_debug("%u: deleting pseudowire %s protocol %s", pw->vrf_id,
+			   pw->ifname, zebra_route_string(pw->protocol));
+
+	/* uninstall */
+	if (pw->status == PW_STATUS_UP)
+		hook_call(pw_uninstall, pw);
+	else if (pw->install_retry_timer)
+		THREAD_TIMER_OFF(pw->install_retry_timer);
+
+	/* unlink and release memory */
+	RB_REMOVE(zebra_pw_head, &zvrf->pseudowires, pw);
+	XFREE(MTYPE_PW, pw);
+}
+
+void zebra_pw_change(struct zebra_pw *pw, ifindex_t ifindex, int type, int af,
+		     union g_addr *nexthop, uint32_t local_label,
+		     uint32_t remote_label, uint8_t flags,
+		     union pw_protocol_fields *data)
+{
+	pw->ifindex = ifindex;
+	pw->type = type;
+	pw->af = af;
+	pw->nexthop = *nexthop;
+	pw->local_label = local_label;
+	pw->remote_label = remote_label;
+	pw->flags = flags;
+	pw->data = *data;
+
+	if (pw->enabled)
+		zebra_pw_update(pw);
+	else
+		zebra_pw_uninstall(pw);
+}
+
+struct zebra_pw *zebra_pw_find(struct zebra_vrf *zvrf, const char *ifname)
+{
+	struct zebra_pw pw;
+	strlcpy(pw.ifname, ifname, sizeof(pw.ifname));
+	return (RB_FIND(zebra_pw_head, &zvrf->pseudowires, &pw));
+}
+
+void zebra_pw_update(struct zebra_pw *pw)
+{
+	if (zebra_pw_check_reachability(pw) < 0) {
+		zebra_pw_uninstall(pw);
+	} else {
+		/*
+		 * Install or reinstall the pseudowire (e.g. to update
+		 * parameters like the nexthop or the use of the control word).
+		 */
+		zebra_pw_install(pw);
+	}
+}
+
+static void zebra_pw_install(struct zebra_pw *pw)
+{
+	if (IS_ZEBRA_DEBUG_PW)
+		zlog_debug("%u: installing pseudowire %s protocol %s",
+			   pw->vrf_id, pw->ifname,
+			   zebra_route_string(pw->protocol));
+
+	if (hook_call(pw_install, pw)) {
+		zebra_pw_install_failure(pw);
+		return;
+	}
+
+	if (pw->status == PW_STATUS_DOWN)
+		zebra_pw_update_status(pw, PW_STATUS_UP);
+}
+
+static void zebra_pw_uninstall(struct zebra_pw *pw)
+{
+	if (pw->status == PW_STATUS_DOWN)
+		return;
+
+	if (IS_ZEBRA_DEBUG_PW)
+		zlog_debug("%u: uninstalling pseudowire %s protocol %s",
+			   pw->vrf_id, pw->ifname,
+			   zebra_route_string(pw->protocol));
+
+	/* ignore any possible error */
+	hook_call(pw_uninstall, pw);
+
+	if (pw->enabled)
+		zebra_pw_update_status(pw, PW_STATUS_DOWN);
+}
+
+/*
+ * Installation of the pseudowire in the kernel or hardware has failed. This
+ * function will notify the pseudowire client about the failure and schedule
+ * to retry the installation later. This function can be called by an external
+ * agent that performs the pseudowire installation in an asynchronous way.
+ */
+void zebra_pw_install_failure(struct zebra_pw *pw)
+{
+	if (IS_ZEBRA_DEBUG_PW)
+		zlog_debug(
+			"%u: failed installing pseudowire %s, "
+			"scheduling retry in %u seconds",
+			pw->vrf_id, pw->ifname, PW_INSTALL_RETRY_INTERVAL);
+
+	/* schedule to retry later */
+	THREAD_TIMER_OFF(pw->install_retry_timer);
+	pw->install_retry_timer =
+		thread_add_timer(zebrad.master, zebra_pw_install_retry, pw,
+				 PW_INSTALL_RETRY_INTERVAL);
+
+	zebra_pw_update_status(pw, PW_STATUS_DOWN);
+}
+
+static int zebra_pw_install_retry(struct thread *thread)
+{
+	struct zebra_pw *pw = THREAD_ARG(thread);
+
+	pw->install_retry_timer = NULL;
+	zebra_pw_install(pw);
+
+	return 0;
+}
+
+static void zebra_pw_update_status(struct zebra_pw *pw, int status)
+{
+	pw->status = status;
+	if (pw->client)
+		zsend_pw_update(pw->client, pw);
+}
+
+static int zebra_pw_check_reachability(struct zebra_pw *pw)
+{
+	struct rib *rib;
+	struct nexthop *nexthop, *tnexthop;
+	int recursing;
+
+	/* TODO: consider GRE/L2TPv3 tunnels in addition to MPLS LSPs */
+
+	/* find route to the remote end of the pseudowire */
+	rib = rib_match(family2afi(pw->af), SAFI_UNICAST, pw->vrf_id,
+			&pw->nexthop, NULL);
+	if (!rib) {
+		if (IS_ZEBRA_DEBUG_PW)
+			zlog_warn("%s: no route found for %s", __func__,
+				  pw->ifname);
+		return -1;
+	}
+
+	/*
+	 * Need to ensure that there's a label binding for all nexthops.
+	 * Otherwise, ECMP for this route could render the pseudowire unusable.
+	 */
+	for (ALL_NEXTHOPS_RO(rib->nexthop, nexthop, tnexthop, recursing)) {
+		if (!nexthop->nh_label) {
+			if (IS_ZEBRA_DEBUG_PW)
+				zlog_warn("%s: unlabeled route for %s",
+					  __func__, pw->ifname);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+void zebra_pw_client_close(struct zserv *client)
+{
+	struct vrf *vrf;
+	struct zebra_vrf *zvrf;
+	struct zebra_pw *pw, *tmp;
+
+	RB_FOREACH(vrf, vrf_id_head, &vrfs_by_id)
+	{
+		zvrf = vrf->info;
+		RB_FOREACH_SAFE(pw, zebra_pw_head, &zvrf->pseudowires, tmp)
+		{
+			if (pw->client != client)
+				continue;
+			zebra_pw_del(zvrf, pw);
+		}
+	}
+}
+
+void zebra_pw_init(struct zebra_vrf *zvrf)
+{
+	RB_INIT(&zvrf->pseudowires);
+}
+
+void zebra_pw_exit(struct zebra_vrf *zvrf)
+{
+	struct zebra_pw *pw;
+
+	while ((pw = RB_ROOT(&zvrf->pseudowires)) != NULL)
+		zebra_pw_del(zvrf, pw);
+}
diff --git a/zebra/zebra_pw.h b/zebra/zebra_pw.h
new file mode 100644
index 000000000..62f45db5c
--- /dev/null
+++ b/zebra/zebra_pw.h
@@ -0,0 +1,67 @@
+/* Zebra PW code
+ * Copyright (C) 2016 Volta Networks, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+ * MA 02110-1301 USA
+ */
+
+#ifndef ZEBRA_PW_H_
+#define ZEBRA_PW_H_
+
+#include <net/if.h>
+#include <netinet/in.h>
+
+#include "hook.h"
+
+#define PW_INSTALL_RETRY_INTERVAL	30
+
+struct zebra_pw {
+	RB_ENTRY(zebra_pw) entry;
+	vrf_id_t vrf_id;
+	char ifname[IF_NAMESIZE];
+	ifindex_t ifindex;
+	int type;
+	int af;
+	union g_addr nexthop;
+	uint32_t local_label;
+	uint32_t remote_label;
+	uint8_t flags;
+	union pw_protocol_fields data;
+	int enabled;
+	int status;
+	uint8_t protocol;
+	struct zserv *client;
+	struct thread *install_retry_timer;
+};
+
+RB_HEAD(zebra_pw_head, zebra_pw);
+RB_PROTOTYPE(zebra_pw_head, zebra_pw, entry, zebra_pw_compare);
+
+DECLARE_HOOK(pw_install, (struct zebra_pw * pw), (pw))
+DECLARE_HOOK(pw_uninstall, (struct zebra_pw * pw), (pw))
+
+struct zebra_pw *zebra_pw_add(struct zebra_vrf *, const char *, uint8_t,
+			      struct zserv *);
+void zebra_pw_del(struct zebra_vrf *, struct zebra_pw *);
+void zebra_pw_change(struct zebra_pw *, ifindex_t, int, int, union g_addr *,
+		     uint32_t, uint32_t, uint8_t, union pw_protocol_fields *);
+struct zebra_pw *zebra_pw_find(struct zebra_vrf *, const char *);
+void zebra_pw_update(struct zebra_pw *);
+void zebra_pw_install_failure(struct zebra_pw *);
+void zebra_pw_client_close(struct zserv *);
+void zebra_pw_init(struct zebra_vrf *);
+void zebra_pw_exit(struct zebra_vrf *);
+
+#endif /* ZEBRA_PW_H_ */
diff --git a/zebra/zebra_vrf.c b/zebra/zebra_vrf.c
index 87c1389b4..ff140bad6 100644
--- a/zebra/zebra_vrf.c
+++ b/zebra/zebra_vrf.c
@@ -203,6 +203,7 @@ static int zebra_vrf_delete(struct vrf *vrf)
 		zebra_vxlan_close_tables(zvrf);
 
 		zebra_mpls_close_tables(zvrf);
+		zebra_pw_exit(zvrf);
 
 		for (ALL_LIST_ELEMENTS_RO(vrf->iflist, node, ifp))
 			if_nbr_ipv6ll_to_ipv4ll_neigh_del_all(ifp);
@@ -372,6 +373,7 @@ struct zebra_vrf *zebra_vrf_alloc(void)
 
 	zebra_vxlan_init_tables(zvrf);
 	zebra_mpls_init_tables(zvrf);
+	zebra_pw_init(zvrf);
 
 	return zvrf;
 }
diff --git a/zebra/zebra_vrf.h b/zebra/zebra_vrf.h
index 3fdbe96dd..a55c9d459 100644
--- a/zebra/zebra_vrf.h
+++ b/zebra/zebra_vrf.h
@@ -23,6 +23,7 @@
 #define __ZEBRA_RIB_H__
 
 #include <zebra/zebra_ns.h>
+#include <zebra/zebra_pw.h>
 
 /* MPLS (Segment Routing) global block */
 typedef struct mpls_srgb_t_ {
@@ -89,6 +90,9 @@ struct zebra_vrf {
 	/* MPLS Segment Routing Global block */
 	mpls_srgb_t mpls_srgb;
 
+	/* Pseudowires. */
+	struct zebra_pw_head pseudowires;
+
 	/* MPLS processing flags */
 	u_int16_t mpls_flags;
 #define MPLS_FLAG_SCHEDULE_LSPS    (1 << 0)
diff --git a/zebra/zserv.c b/zebra/zserv.c
index dae6785ae..bdb7755b6 100644
--- a/zebra/zserv.c
+++ b/zebra/zserv.c
@@ -1085,6 +1085,27 @@ int zsend_router_id_update(struct zserv *client, struct prefix *p,
 	return zebra_server_send_message(client);
 }
 
+/*
+ * Function used by Zebra to send a PW status update to LDP daemon
+ */
+int zsend_pw_update(struct zserv *client, struct zebra_pw *pw)
+{
+	struct stream *s;
+
+	s = client->obuf;
+	stream_reset(s);
+
+	zserv_create_header(s, ZEBRA_PW_STATUS_UPDATE, pw->vrf_id);
+	stream_write(s, pw->ifname, IF_NAMESIZE);
+	stream_putl(s, pw->ifindex);
+	stream_putl(s, pw->status);
+
+	/* Put length at the first point of the stream. */
+	stream_putw_at(s, 0, stream_get_endp(s));
+
+	return zebra_server_send_message(client);
+}
+
 /* Register zebra server interface information.  Send current all
    interface and address information. */
 static int zread_interface_add(struct zserv *client, u_short length,
@@ -2037,6 +2058,97 @@ static void zread_label_manager_request(int cmd, struct zserv *client,
 	}
 }
 
+static int zread_pseudowire(int command, struct zserv *client, u_short length,
+			    vrf_id_t vrf_id)
+{
+	struct stream *s;
+	struct zebra_vrf *zvrf;
+	char ifname[IF_NAMESIZE];
+	ifindex_t ifindex;
+	int type;
+	int af;
+	union g_addr nexthop;
+	uint32_t local_label;
+	uint32_t remote_label;
+	uint8_t flags;
+	union pw_protocol_fields data;
+	uint8_t protocol;
+	struct zebra_pw *pw;
+
+	zvrf = vrf_info_lookup(vrf_id);
+	if (!zvrf)
+		return -1;
+
+	/* Get input stream.  */
+	s = client->ibuf;
+
+	/* Get data. */
+	stream_get(ifname, s, IF_NAMESIZE);
+	ifindex = stream_getl(s);
+	type = stream_getl(s);
+	af = stream_getl(s);
+	switch (af) {
+	case AF_INET:
+		nexthop.ipv4.s_addr = stream_get_ipv4(s);
+		break;
+	case AF_INET6:
+		stream_get(&nexthop.ipv6, s, 16);
+		break;
+	default:
+		return -1;
+	}
+	local_label = stream_getl(s);
+	remote_label = stream_getl(s);
+	flags = stream_getc(s);
+	stream_get(&data, s, sizeof(data));
+	protocol = client->proto;
+
+	pw = zebra_pw_find(zvrf, ifname);
+	switch (command) {
+	case ZEBRA_PW_ADD:
+		if (pw) {
+			zlog_warn("%s: pseudowire %s already exists [%s]",
+				  __func__, ifname,
+				  zserv_command_string(command));
+			return -1;
+		}
+
+		zebra_pw_add(zvrf, ifname, protocol, client);
+		break;
+	case ZEBRA_PW_DELETE:
+		if (!pw) {
+			zlog_warn("%s: pseudowire %s not found [%s]", __func__,
+				  ifname, zserv_command_string(command));
+			return -1;
+		}
+
+		zebra_pw_del(zvrf, pw);
+		break;
+	case ZEBRA_PW_SET:
+	case ZEBRA_PW_UNSET:
+		if (!pw) {
+			zlog_warn("%s: pseudowire %s not found [%s]", __func__,
+				  ifname, zserv_command_string(command));
+			return -1;
+		}
+
+		switch (command) {
+		case ZEBRA_PW_SET:
+			pw->enabled = 1;
+			break;
+		case ZEBRA_PW_UNSET:
+			pw->enabled = 0;
+			break;
+		}
+
+		zebra_pw_change(pw, ifindex, type, af, &nexthop, local_label,
+				remote_label, flags, &data);
+		break;
+	}
+
+	return 0;
+}
+
 /* Cleanup registered nexthops (across VRFs) upon client disconnect. */
 static void zebra_client_close_cleanup_rnh(struct zserv *client)
 {
@@ -2081,6 +2193,9 @@ static void zebra_client_close(struct zserv *client)
 	zebra_mpls_cleanup_fecs_for_client(vrf_info_lookup(VRF_DEFAULT),
 					   client);
 
+	/* Remove pseudowires associated with this client */
+	zebra_pw_client_close(client);
+
 	/* Close file descriptor. */
 	if (client->sock) {
 		unsigned long nroutes;
@@ -2434,6 +2549,12 @@ static int zebra_client_read(struct thread *thread)
 	case ZEBRA_INTERFACE_SET_MASTER:
 		zread_interface_set_master(client, sock, length);
 		break;
+	case ZEBRA_PW_ADD:
+	case ZEBRA_PW_DELETE:
+	case ZEBRA_PW_SET:
+	case ZEBRA_PW_UNSET:
+		zread_pseudowire(command, client, length, vrf_id);
+		break;
 	default:
 		zlog_info("Zebra received unknown command %d", command);
 		break;
diff --git a/zebra/zserv.h b/zebra/zserv.h
index a2cf5d9f4..f661572d5 100644
--- a/zebra/zserv.h
+++ b/zebra/zserv.h
@@ -30,6 +30,8 @@
 #include "zclient.h"
 
 #include "zebra/zebra_ns.h"
+#include "zebra/zebra_pw.h"
+
 /* Default port information. */
 #define ZEBRA_VTY_PORT                2601
 
@@ -175,6 +177,7 @@ extern int zsend_interface_vrf_update(struct zserv *, struct interface *,
 				      vrf_id_t);
 
 extern int zsend_interface_link_params(struct zserv *, struct interface *);
+extern int zsend_pw_update(struct zserv *, struct zebra_pw *);
 
 extern pid_t pid;