zebra: Start of work to get data about mpls from kernel

a) We'll need to pass the info up via some dataplane control method
(This way bsd and linux can both be zebra agnostic of each other)

b) We'll need to modify `struct interface *` to track this data
and when it changes to notify upper level protocols about it.

c) Work is needed to dump the entire mpls state at the start
so we can gather interface state.  This should be done
after interface data gathering from the kernel.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>
Signed-off-by: Mark Stapp <mstapp@nvidia.com>

include/linux/netconf.h

@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_LINUX_NETCONF_H_
+#define _UAPI_LINUX_NETCONF_H_
+
+#include <linux/types.h>
+#include <linux/netlink.h>
+
+struct netconfmsg {
+	__u8	ncm_family;
+};
+
+enum {
+	NETCONFA_UNSPEC,
+	NETCONFA_IFINDEX,
+	NETCONFA_FORWARDING,
+	NETCONFA_RP_FILTER,
+	NETCONFA_MC_FORWARDING,
+	NETCONFA_PROXY_NEIGH,
+	NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN,
+	NETCONFA_INPUT,
+	NETCONFA_BC_FORWARDING,
+	__NETCONFA_MAX
+};
+#define NETCONFA_MAX	(__NETCONFA_MAX - 1)
+#define NETCONFA_ALL	-1
+
+#define NETCONFA_IFINDEX_ALL		-1
+#define NETCONFA_IFINDEX_DEFAULT	-2
+
+#endif /* _UAPI_LINUX_NETCONF_H_ */

include/subdir.am

@@ -5,6 +5,7 @@ noinst_HEADERS += \
 	include/linux/lwtunnel.h \
 	include/linux/mpls_iptunnel.h \
 	include/linux/neighbour.h \
+	include/linux/netconf.h \
 	include/linux/netlink.h \
 	include/linux/nexthop.h \
 	include/linux/rtnetlink.h \

zebra/if_netlink.c

@@ -74,6 +74,7 @@
 #include "zebra/zebra_vxlan.h"
 #include "zebra/zebra_evpn_mh.h"
 #include "zebra/zebra_l2.h"
+#include "zebra/netconf_netlink.h"
 
 extern struct zebra_privs_t zserv_privs;
 
@@ -1001,6 +1002,7 @@ static int netlink_interface(struct nlmsghdr *h, ns_id_t ns_id, int startup)
 
 	/* Hardware type and address. */
 	ifp->ll_type = netlink_to_zebra_link_type(ifi->ifi_type);
+
 	netlink_interface_update_hw_addr(tb, ifp);
 
 	if_add_update(ifp);
@@ -2078,6 +2080,10 @@ void interface_list(struct zebra_ns *zns)
 	netlink_nexthop_read(zns);
 
 	interface_addr_lookup_netlink(zns);
+
+	/* Read some other properties via the 'netconf' apis */
+	netconf_lookup_netlink(zns);
+
 }
 
 #endif /* GNU_LINUX */

zebra/kernel_netlink.c

@@ -48,6 +48,7 @@
 #include "zebra/rt_netlink.h"
 #include "zebra/if_netlink.h"
 #include "zebra/rule_netlink.h"
+#include "zebra/netconf_netlink.h"
 #include "zebra/zebra_errors.h"
 
 #ifndef SO_RCVBUFFORCE
@@ -108,6 +109,8 @@ static const struct message nlmsg_str[] = {{RTM_NEWROUTE, "RTM_NEWROUTE"},
 					   {RTM_NEWNEXTHOP, "RTM_NEWNEXTHOP"},
 					   {RTM_DELNEXTHOP, "RTM_DELNEXTHOP"},
 					   {RTM_GETNEXTHOP, "RTM_GETNEXTHOP"},
+					   {RTM_NEWNETCONF, "RTM_NEWNETCONF"},
+					   {RTM_DELNETCONF, "RTM_DELNETCONF"},
 					   {0}};
 
 static const struct message rtproto_str[] = {
@@ -370,6 +373,10 @@ static int netlink_information_fetch(struct nlmsghdr *h, ns_id_t ns_id,
 	case RTM_DELNEXTHOP:
 		return netlink_nexthop_change(h, ns_id, startup);
 
+	case RTM_NEWNETCONF:
+	case RTM_DELNETCONF:
+		return netlink_netconf_change(h, ns_id, startup);
+
 	/* Messages handled in the dplane thread */
 	case RTM_NEWADDR:
 	case RTM_DELADDR:
@@ -1593,7 +1600,9 @@ void kernel_init(struct zebra_ns *zns)
 		RTMGRP_NEIGH                   |
 		((uint32_t) 1 << (RTNLGRP_IPV4_RULE - 1)) |
 		((uint32_t) 1 << (RTNLGRP_IPV6_RULE - 1)) |
-		((uint32_t) 1 << (RTNLGRP_NEXTHOP - 1));
+		((uint32_t) 1 << (RTNLGRP_NEXTHOP - 1)) |
+		((uint32_t) 1 << (RTNLGRP_IPV4_NETCONF - 1)) |
+		((uint32_t) 1 << (RTNLGRP_MPLS_NETCONF - 1));
 
 	dplane_groups = (RTMGRP_LINK            |
 			 RTMGRP_IPV4_IFADDR     |

zebra/netconf_netlink.c

@@ -0,0 +1,139 @@
+/*
+ * netconf_netlink.c - netconf interaction with the kernel using
+ * netlink
+ * Copyright (C) 2021  Nvidia, Inc.
+ *                     Donald Sharp
+ *
+ * This file is part of FRR.
+ *
+ * FRR 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, or (at your option) any
+ * later version.
+ *
+ * FRR 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 FRR; see the file COPYING.  If not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+#include <zebra.h>
+
+#ifdef HAVE_NETLINK /* Netlink OSes only */
+
+#include <ns.h>
+
+#include "linux/netconf.h"
+
+#include "zebra/zebra_ns.h"
+#include "zebra/zebra_dplane.h"
+#include "zebra/kernel_netlink.h"
+#include "zebra/netconf_netlink.h"
+#include "zebra/debug.h"
+
+static struct rtattr *netconf_rta(struct netconfmsg *ncm)
+{
+	return (struct rtattr *)((char *)ncm
+				 + NLMSG_ALIGN(sizeof(struct netconfmsg)));
+}
+
+int netlink_netconf_change(struct nlmsghdr *h, ns_id_t ns_id, int startup)
+{
+	struct netconfmsg *ncm;
+	struct rtattr *tb[NETCONFA_MAX + 1] = {};
+	int len;
+	ifindex_t ifindex;
+	bool mpls_on = false;
+	bool mc_on = false;
+
+	if (h->nlmsg_type != RTM_NEWNETCONF && h->nlmsg_type != RTM_DELNETCONF)
+		return 0;
+
+	len = h->nlmsg_len - NLMSG_LENGTH(sizeof(struct netconfmsg));
+	if (len < 0) {
+		zlog_err("%s: Message received from netlink is of a broken size: %d %zu",
+			 __func__, h->nlmsg_len,
+			 (size_t)NLMSG_LENGTH(sizeof(struct netconfmsg)));
+		return -1;
+	}
+
+	ncm = NLMSG_DATA(h);
+
+	netlink_parse_rtattr(tb, NETCONFA_MAX, netconf_rta(ncm), len);
+
+	if (!tb[NETCONFA_IFINDEX]) {
+		zlog_err("%s: Message received from netlink that we expected to receive an interface on",
+			__func__);
+		return 0;
+	}
+
+	ifindex = *(ifindex_t *)RTA_DATA(tb[NETCONFA_IFINDEX]);
+
+	switch (ifindex) {
+	case NETCONFA_IFINDEX_ALL:
+	case NETCONFA_IFINDEX_DEFAULT:
+		/*
+		 * We need the ability to handle netlink messages intended
+		 * for all and default interfaces.  I am not 100% sure
+		 * what that is yet, or where we would store it.
+		 */
+		return 0;
+	default:
+		break;
+	}
+	if (tb[NETCONFA_INPUT]) {
+		mpls_on = *(bool *)RTA_DATA(tb[NETCONFA_INPUT]);
+		/* Create a context and pass it up for processing */
+	}
+
+	if (tb[NETCONFA_MC_FORWARDING]) {
+		mc_on = *(bool *)RTA_DATA(tb[NETCONFA_MC_FORWARDING]);
+		/* Create a context and pass it up for processing */
+	}
+
+	if (IS_ZEBRA_DEBUG_KERNEL)
+		zlog_debug("Interface %u is mpls on: %d multicast on: %d",
+			   ifindex, mpls_on, mc_on);
+
+	return 0;
+}
+
+static int netlink_request_netconf(struct nlsock *netlink_cmd)
+{
+	struct {
+		struct nlmsghdr n;
+		struct netconfmsg ncm;
+		char buf[1024];
+	} req;
+
+	memset(&req, 0, sizeof(req));
+	req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct netconfmsg));
+	req.n.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST;
+	req.n.nlmsg_type = RTM_GETNETCONF;
+	req.ncm.ncm_family = AF_UNSPEC;
+
+	return netlink_request(netlink_cmd, &req);
+}
+
+int netconf_lookup_netlink(struct zebra_ns *zns)
+{
+	int ret;
+	struct zebra_dplane_info dp_info;
+	struct nlsock *netlink_cmd = &zns->netlink_cmd;
+
+	zebra_dplane_info_from_zns(&dp_info, zns, true);
+
+	ret = netlink_request_netconf(netlink_cmd);
+	if (ret < 0)
+		return ret;
+
+	ret = netlink_parse_info(netlink_netconf_change, netlink_cmd, &dp_info,
+				 0, 1);
+	return ret;
+}
+
+#endif	/* HAVE_NETLINK */

zebra/netconf_netlink.h

@@ -0,0 +1,45 @@
+/*
+ * netconf_netlink.h - netconf interaction with the kernel using
+ * netlink
+ * Copyright (C) 2021  Nvidia, Inc.
+ *                     Donald Sharp
+ *
+ * This file is part of FRR.
+ *
+ * FRR 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, or (at your option) any
+ * later version.
+ *
+ * FRR 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 FRR; see the file COPYING.  If not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+#ifndef __NETCONF_NETLINK_H__
+#define __NETCONF_NETLINK_H__
+
+#ifdef HAVE_NETLINK /* Netlink-only module */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern int netlink_netconf_change(struct nlmsghdr *h, ns_id_t ns_id,
+				  int startup);
+
+extern int netconf_lookup_netlink(struct zebra_ns *zns);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* HAVE_NETLINK */
+
+#endif	/* NETCONF_NETLINK_H */

zebra/subdir.am

@@ -69,6 +69,7 @@ zebra_zebra_SOURCES = \
 	zebra/kernel_socket.c \
 	zebra/label_manager.c \
 	zebra/main.c \
+	zebra/netconf_netlink.c \
 	zebra/redistribute.c \
 	zebra/router-id.c \
 	zebra/rt_netlink.c \
@@ -148,6 +149,7 @@ noinst_HEADERS += \
 	zebra/kernel_netlink.h \
 	zebra/kernel_socket.h \
 	zebra/label_manager.h \
+	zebra/netconf_netlink.h \
 	zebra/redistribute.h \
 	zebra/rib.h \
 	zebra/router-id.h \