zebra: Add a mpls enable interface node command

Allow individual interfaces to turn on/off the mpls subsystem
for it in linux.

sharpd@eva:~/frr9$ sudo sysctl -a | grep enp39s0 | grep mpls
net.mpls.conf.enp39s0.input = 0
sharpd@eva:~/frr9$ vtysh -c "conf" -c "int enp39s0" -c "mpls enable"
sharpd@eva:~/frr9$ sudo sysctl -a | grep enp39s0 | grep mpls
net.mpls.conf.enp39s0.input = 1
sharpd@eva:~/frr9$ vtysh -c "conf" -c "int enp39s0" -c "no mpls enable"
sharpd@eva:~/frr9$ sudo sysctl -a | grep enp39s0 | grep mpls
net.mpls.conf.enp39s0.input = 0
sharpd@eva:~/frr9$

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

doc/user/zebra.rst

@@ -155,6 +155,13 @@ Standard Commands
    Set description for the interface.
 
 
+.. clicmd:: mpls enable
+
+   Enable or disable mpls kernel processing on the interface, for linux.  Interfaces
+   configured with mpls will not automatically turn on if mpls kernel modules do not
+   happen to be loaded.  This command will fail on 3.X linux kernels and does not
+   work on non-linux systems at all.
+
 .. clicmd:: multicast
 
 

zebra/if_socket.c

@@ -38,4 +38,15 @@ enum zebra_dplane_result kernel_intf_update(struct zebra_dplane_ctx *ctx)
 	return ZEBRA_DPLANE_REQUEST_FAILURE;
 }
 
+enum zebra_dplane_result
+kernel_intf_netconf_update(struct zebra_dplane_ctx *ctx)
+{
+	const char *ifname = dplane_ctx_get_ifname(ctx);
+	enum dplane_netconf_status_e mpls_on = dplane_ctx_get_netconf_mpls(ctx);
+
+	zlog_warn("%s:  Unable to set kernel mpls state for interface %s(%d)",
+		  __func__, ifname, mpls_on);
+
+	return ZEBRA_DPLANE_REQUEST_SUCCESS;
+}
 #endif

zebra/interface.c

@@ -2937,6 +2937,27 @@ DEFUN (multicast,
 	return CMD_SUCCESS;
 }
 
+DEFPY (mpls,
+       mpls_cmd,
+       "[no] mpls enable",
+       NO_STR
+       MPLS_STR
+       "Set mpls to be on for the interface\n")
+{
+	VTY_DECLVAR_CONTEXT(interface, ifp);
+	struct zebra_if *if_data = ifp->info;
+
+	if (no) {
+		dplane_intf_mpls_modify_state(ifp, false);
+		if_data->mpls = IF_ZEBRA_DATA_UNSPEC;
+	} else {
+		dplane_intf_mpls_modify_state(ifp, true);
+		if_data->mpls = IF_ZEBRA_DATA_ON;
+	}
+
+	return CMD_SUCCESS;
+}
+
 int if_multicast_unset(struct interface *ifp)
 {
 	struct zebra_if *if_data;
@@ -4581,6 +4602,8 @@ static int if_config_write(struct vty *vty)
 								IF_ZEBRA_DATA_ON
 							? ""
 							: "no ");
+				if (if_data->mpls == IF_ZEBRA_DATA_ON)
+					vty_out(vty, " mpls\n");
 			}
 
 			hook_call(zebra_if_config_wr, vty, ifp);
@@ -4617,6 +4640,7 @@ void zebra_if_init(void)
 	install_element(ENABLE_NODE, &show_interface_desc_vrf_all_cmd);
 	install_element(INTERFACE_NODE, &multicast_cmd);
 	install_element(INTERFACE_NODE, &no_multicast_cmd);
+	install_element(INTERFACE_NODE, &mpls_cmd);
 	install_element(INTERFACE_NODE, &linkdetect_cmd);
 	install_element(INTERFACE_NODE, &no_linkdetect_cmd);
 	install_element(INTERFACE_NODE, &shutdown_if_cmd);

zebra/kernel_netlink.c

@@ -1613,10 +1613,12 @@ static enum netlink_msg_status nl_put_msg(struct nl_batch *bth,
 
 	case DPLANE_OP_INTF_ADDR_ADD:
 	case DPLANE_OP_INTF_ADDR_DEL:
-	case DPLANE_OP_INTF_NETCONFIG:
 	case DPLANE_OP_NONE:
 		return FRR_NETLINK_ERROR;
 
+	case DPLANE_OP_INTF_NETCONFIG:
+		return netlink_put_intf_netconfig(bth, ctx);
+
 	case DPLANE_OP_INTF_INSTALL:
 	case DPLANE_OP_INTF_UPDATE:
 	case DPLANE_OP_INTF_DELETE:

zebra/kernel_socket.c

@@ -1529,7 +1529,7 @@ void kernel_update_multi(struct dplane_ctx_q *ctx_list)
 {
 	struct zebra_dplane_ctx *ctx;
 	struct dplane_ctx_q handled_list;
-	enum zebra_dplane_result res;
+	enum zebra_dplane_result res = ZEBRA_DPLANE_REQUEST_SUCCESS;
 
 	TAILQ_INIT(&handled_list);
 
@@ -1611,9 +1611,27 @@ void kernel_update_multi(struct dplane_ctx_q *ctx_list)
 			res = ZEBRA_DPLANE_REQUEST_SUCCESS;
 			break;
 
-		default:
+		case DPLANE_OP_INTF_NETCONFIG:
-			res = ZEBRA_DPLANE_REQUEST_FAILURE;
+			res = kernel_intf_netconf_update(ctx);
 			break;
+
+		case DPLANE_OP_NONE:
+		case DPLANE_OP_BR_PORT_UPDATE:
+		case DPLANE_OP_IPTABLE_ADD:
+		case DPLANE_OP_IPTABLE_DELETE:
+		case DPLANE_OP_IPSET_ADD:
+		case DPLANE_OP_IPSET_DELETE:
+		case DPLANE_OP_IPSET_ENTRY_ADD:
+		case DPLANE_OP_IPSET_ENTRY_DELETE:
+		case DPLANE_OP_NEIGH_IP_INSTALL:
+		case DPLANE_OP_NEIGH_IP_DELETE:
+		case DPLANE_OP_NEIGH_TABLE_UPDATE:
+		case DPLANE_OP_GRE_SET:
+		case DPLANE_OP_INTF_ADDR_ADD:
+		case DPLANE_OP_INTF_ADDR_DEL:
+			zlog_err("Unhandled dplane data for %s",
+				 dplane_op2str(dplane_ctx_get_op(ctx)));
+			res = ZEBRA_DPLANE_REQUEST_FAILURE;
 		}
 
 	skip_one:

zebra/netconf_netlink.c

@@ -29,6 +29,7 @@
 
 #include "linux/netconf.h"
 
+#include "lib/lib_errors.h"
 #include "zebra/zebra_ns.h"
 #include "zebra/zebra_dplane.h"
 #include "zebra/kernel_netlink.h"
@@ -185,4 +186,56 @@ int netlink_request_netconf(int sockfd)
 	return netlink_request(nls, &req);
 }
 
+extern struct zebra_privs_t zserv_privs;
+/*
+ * Currently netconf has no ability to set from netlink.
+ * So we've received a request to do this work in the data plane.
+ * as such we need to set the value via the /proc system
+ */
+enum netlink_msg_status netlink_put_intf_netconfig(struct nl_batch *bth,
+						   struct zebra_dplane_ctx *ctx)
+{
+	const char *ifname = dplane_ctx_get_ifname(ctx);
+	enum dplane_netconf_status_e mpls_on = dplane_ctx_get_netconf_mpls(ctx);
+	char set[64];
+	char mpls_proc[PATH_MAX];
+	int fd, ret = FRR_NETLINK_ERROR;
+
+	snprintf(mpls_proc, sizeof(mpls_proc),
+		 "/proc/sys/net/mpls/conf/%s/input", ifname);
+
+	if (mpls_on == DPLANE_NETCONF_STATUS_ENABLED)
+		snprintf(set, sizeof(set), "1\n");
+	else if (mpls_on == DPLANE_NETCONF_STATUS_DISABLED)
+		snprintf(set, sizeof(set), "0\n");
+	else {
+		flog_err_sys(
+			EC_LIB_DEVELOPMENT,
+			"%s: Expected interface %s to be set to ENABLED or DISABLED was %d",
+			__func__, ifname, mpls_on);
+		return ret;
+	}
+
+	frr_with_privs (&zserv_privs) {
+		fd = open(mpls_proc, O_WRONLY);
+		if (fd < 0) {
+			flog_err_sys(
+				EC_LIB_SOCKET,
+				"%s: Unable to open %s for writing: %s(%d)",
+				__func__, mpls_proc, safe_strerror(errno),
+				errno);
+			return ret;
+		}
+		if (write(fd, set, 2) == 2)
+			ret = FRR_NETLINK_SUCCESS;
+		else
+			flog_err_sys(EC_LIB_SOCKET,
+				     "%s: Unsuccessful write to %s: %s(%d)",
+				     __func__, mpls_proc, safe_strerror(errno),
+				     errno);
+		close(fd);
+	}
+	return ret;
+}
+
 #endif	/* HAVE_NETLINK */

zebra/netconf_netlink.h

@@ -38,6 +38,10 @@ extern int netlink_netconf_change(struct nlmsghdr *h, ns_id_t ns_id,
 /* Request info from the host OS. */
 int netlink_request_netconf(int sockfd);
 
+struct nl_batch;
+
+extern enum netlink_msg_status
+netlink_put_intf_netconfig(struct nl_batch *bth, struct zebra_dplane_ctx *ctx);
 
 #ifdef __cplusplus
 }

zebra/rt.h

@@ -69,6 +69,9 @@ kernel_pbr_rule_update(struct zebra_dplane_ctx *ctx);
 extern enum zebra_dplane_result
 kernel_intf_update(struct zebra_dplane_ctx *ctx);
 
+extern enum zebra_dplane_result
+kernel_intf_netconf_update(struct zebra_dplane_ctx *ctx);
+
 #endif /* !HAVE_NETLINK */
 
 extern int kernel_neigh_update(int cmd, int ifindex, void *addr, char *lla,

zebra/zebra_dplane.c

@@ -509,6 +509,8 @@ static struct zebra_dplane_globals {
 
 	_Atomic uint32_t dg_intf_addrs_in;
 	_Atomic uint32_t dg_intf_addr_errors;
+	_Atomic uint32_t dg_intf_changes;
+	_Atomic uint32_t dg_intf_changes_errors;
 
 	_Atomic uint32_t dg_macs_in;
 	_Atomic uint32_t dg_mac_errors;
@@ -3913,6 +3915,47 @@ dplane_br_port_update(const struct interface *ifp, bool non_df,
 	return result;
 }
 
+enum zebra_dplane_result
+dplane_intf_mpls_modify_state(const struct interface *ifp, bool set)
+{
+	enum zebra_dplane_result result = ZEBRA_DPLANE_REQUEST_FAILURE;
+	struct zebra_dplane_ctx *ctx;
+	struct zebra_ns *zns;
+	int ret = EINVAL;
+
+	ctx = dplane_ctx_alloc();
+	ctx->zd_op = DPLANE_OP_INTF_NETCONFIG;
+	ctx->zd_status = ZEBRA_DPLANE_REQUEST_SUCCESS;
+	ctx->zd_vrf_id = ifp->vrf->vrf_id;
+	strlcpy(ctx->zd_ifname, ifp->name, sizeof(ctx->zd_ifname));
+
+	zns = zebra_ns_lookup(ifp->vrf->vrf_id);
+	dplane_ctx_ns_init(ctx, zns, false);
+
+	ctx->zd_ifindex = ifp->ifindex;
+	if (set)
+		dplane_ctx_set_netconf_mpls(ctx, DPLANE_NETCONF_STATUS_ENABLED);
+	else
+		dplane_ctx_set_netconf_mpls(ctx,
+					    DPLANE_NETCONF_STATUS_DISABLED);
+	/* Increment counter */
+	atomic_fetch_add_explicit(&zdplane_info.dg_intf_changes, 1,
+				  memory_order_relaxed);
+
+	ret = dplane_update_enqueue(ctx);
+
+	if (ret == AOK)
+		result = ZEBRA_DPLANE_REQUEST_QUEUED;
+	else {
+		/* Error counter */
+		atomic_fetch_add_explicit(&zdplane_info.dg_intf_changes_errors,
+					  1, memory_order_relaxed);
+		dplane_ctx_free(&ctx);
+	}
+
+	return result;
+}
+
 /*
  * Enqueue interface address add for the dataplane.
  */
@@ -4900,6 +4943,13 @@ int dplane_show_helper(struct vty *vty, bool detailed)
 	vty_out(vty, "Intf addr updates:        %"PRIu64"\n", incoming);
 	vty_out(vty, "Intf addr errors:         %"PRIu64"\n", errs);
 
+	incoming = atomic_load_explicit(&zdplane_info.dg_intf_changes,
+					memory_order_relaxed);
+	errs = atomic_load_explicit(&zdplane_info.dg_intf_changes_errors,
+				    memory_order_relaxed);
+	vty_out(vty, "Intf change updates:        %" PRIu64 "\n", incoming);
+	vty_out(vty, "Intf change errors:         %" PRIu64 "\n", errs);
+
 	incoming = atomic_load_explicit(&zdplane_info.dg_macs_in,
 					memory_order_relaxed);
 	errs = atomic_load_explicit(&zdplane_info.dg_mac_errors,

zebra/zebra_dplane.h

@@ -690,6 +690,8 @@ enum zebra_dplane_result dplane_lsp_notif_update(struct zebra_lsp *lsp,
 enum zebra_dplane_result dplane_pw_install(struct zebra_pw *pw);
 enum zebra_dplane_result dplane_pw_uninstall(struct zebra_pw *pw);
 
+enum zebra_dplane_result
+dplane_intf_mpls_modify_state(const struct interface *ifp, const bool set);
 /*
  * Enqueue interface address changes for the dataplane.
  */