[lldp] Add support for the Link Layer Discovery Protocol
Add support for recording LLDP packets and exposing TLV values via the
settings mechanism. LLDP settings are encoded as
${netX.lldp/<prefix>.<type>.<index>.<offset>.<length>}
where
<type> is the TLV type
<offset> is the starting offset within the TLV value
<length> is the length (or zero to read the from <offset> to the end)
<prefix>, if it has a non-zero value, is the subtype byte string of
length <offset> to match at the start of the TLV value, up to a
maximum matched length of 4 bytes
<index> is the index of the entry matching <type> and <prefix> to be
accessed, with zero indicating the first matching entry
The <prefix> is designed to accommodate both matching of the OUI
within an organization-specific TLV (e.g. 0x0080c2 for IEEE 802.1
TLVs) and of a subtype byte as found within many TLVs.
This encoding allows most LLDP values to be extracted easily. For
example
System name: ${netX.lldp/5.0.0.0:string}
System description: ${netX.lldp/6.0.0.0:string}
Port description: ${netX.lldp/4.0.0.0:string}
Port interface name: ${netX.lldp/5.2.0.1.0:string}
Chassis MAC address: ${netX.lldp/4.1.0.1.0:hex}
Management IPv4 address: ${netX.lldp/5.1.8.0.2.4:ipv4}
Port VLAN ID: ${netX.lldp/0x0080c2.1.127.0.4.2:int16}
Port VLAN name: ${netX.lldp/0x0080c2.3.127.0.7.0:string}
Maximum frame size: ${netX.lldp/0x00120f.4.127.0.4.2:uint16}
Originally-implemented-by: Marin Hannache <git@mareo.fr>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
diff --git a/src/config/config_ethernet.c b/src/config/config_ethernet.c
index 8a663c9..c1b35bf 100644
--- a/src/config/config_ethernet.c
+++ b/src/config/config_ethernet.c
@@ -49,3 +49,6 @@
#ifdef NET_PROTO_EAPOL
REQUIRE_OBJECT ( eapol );
#endif
+#ifdef NET_PROTO_LLDP
+REQUIRE_OBJECT ( lldp );
+#endif
diff --git a/src/config/general.h b/src/config/general.h
index 2d15f50..e9ceaff 100644
--- a/src/config/general.h
+++ b/src/config/general.h
@@ -40,6 +40,7 @@
#define NET_PROTO_STP /* Spanning Tree protocol */
#define NET_PROTO_LACP /* Link Aggregation control protocol */
#define NET_PROTO_EAPOL /* EAP over LAN protocol */
+#undef NET_PROTO_LLDP /* Link Layer Discovery protocol */
/*
* PXE support
diff --git a/src/include/ipxe/errfile.h b/src/include/ipxe/errfile.h
index 7c3b0c4..d7b6ea1 100644
--- a/src/include/ipxe/errfile.h
+++ b/src/include/ipxe/errfile.h
@@ -295,6 +295,7 @@
#define ERRFILE_ntp ( ERRFILE_NET | 0x00490000 )
#define ERRFILE_httpntlm ( ERRFILE_NET | 0x004a0000 )
#define ERRFILE_eap ( ERRFILE_NET | 0x004b0000 )
+#define ERRFILE_lldp ( ERRFILE_NET | 0x004c0000 )
#define ERRFILE_image ( ERRFILE_IMAGE | 0x00000000 )
#define ERRFILE_elf ( ERRFILE_IMAGE | 0x00010000 )
diff --git a/src/include/ipxe/if_ether.h b/src/include/ipxe/if_ether.h
index 58d91b9..c1168b1 100644
--- a/src/include/ipxe/if_ether.h
+++ b/src/include/ipxe/if_ether.h
@@ -23,6 +23,7 @@
#define ETH_P_SLOW 0x8809 /* Ethernet slow protocols */
#define ETH_P_EAPOL 0x888E /* 802.1X EAP over LANs */
#define ETH_P_AOE 0x88A2 /* ATA over Ethernet */
+#define ETH_P_LLDP 0x88CC /* Link Layer Discovery Protocol */
#define ETH_P_FCOE 0x8906 /* Fibre Channel over Ethernet */
#define ETH_P_FIP 0x8914 /* FCoE Initialization Protocol */
diff --git a/src/include/ipxe/lldp.h b/src/include/ipxe/lldp.h
new file mode 100644
index 0000000..9951d3b
--- /dev/null
+++ b/src/include/ipxe/lldp.h
@@ -0,0 +1,97 @@
+#ifndef _IPXE_LLDP_H
+#define _IPXE_LLDP_H
+
+/** @file
+ *
+ * Link Layer Discovery Protocol
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdint.h>
+
+/** An LLDP TLV header */
+struct lldp_tlv {
+ /** Type and length */
+ uint16_t type_len;
+ /** Data */
+ uint8_t data[0];
+} __attribute__ (( packed ));
+
+/**
+ * Extract LLDP TLV type
+ *
+ * @v type_len Type and length
+ * @ret type Type
+ */
+#define LLDP_TLV_TYPE( type_len ) ( (type_len) >> 9 )
+
+/**
+ * Extract LLDP TLV length
+ *
+ * @v type_len Type and length
+ * @ret len Length
+ */
+#define LLDP_TLV_LEN( type_len ) ( (type_len) & 0x01ff )
+
+/** End of LLDP data unit */
+#define LLDP_TYPE_END 0x00
+
+/** LLDP settings block name */
+#define LLDP_SETTINGS_NAME "lldp"
+
+/**
+ * Construct LLDP setting tag
+ *
+ * LLDP settings are encoded as
+ *
+ * ${netX.lldp/<prefix>.<type>.<index>.<offset>.<length>}
+ *
+ * where
+ *
+ * <type> is the TLV type
+ *
+ * <offset> is the starting offset within the TLV value
+ *
+ * <length> is the length (or zero to read the from <offset> to the end)
+ *
+ * <prefix>, if it has a non-zero value, is the subtype byte string
+ * of length <offset> to match at the start of the TLV value, up to
+ * a maximum matched length of 4 bytes
+ *
+ * <index> is the index of the entry matching <type> and <prefix> to
+ * be accessed, with zero indicating the first matching entry
+ *
+ * The <prefix> is designed to accommodate both matching of the OUI
+ * within an organization-specific TLV (e.g. 0x0080c2 for IEEE 802.1
+ * TLVs) and of a subtype byte as found within many TLVs.
+ *
+ * This encoding allows most LLDP values to be extracted easily. For
+ * example
+ *
+ * System name: ${netX.lldp/5.0.0.0:string}
+ *
+ * System description: ${netX.lldp/6.0.0.0:string}
+ *
+ * Port description: ${netX.lldp/4.0.0.0:string}
+ *
+ * Port interface name: ${netX.lldp/5.2.0.1.0:string}
+ *
+ * Chassis MAC address: ${netX.lldp/4.1.0.1.0:hex}
+ *
+ * Management IPv4 address: ${netX.lldp/5.1.8.0.2.4:ipv4}
+ *
+ * Port VLAN ID: ${netX.lldp/0x0080c2.1.127.0.4.2:int16}
+ *
+ * Port VLAN name: ${netX.lldp/0x0080c2.3.127.0.7.0:string}
+ *
+ * Maximum frame size: ${netX.lldp/0x00120f.4.127.0.4.2:uint16}
+ *
+ */
+#define LLDP_TAG( prefix, type, index, offset, length ) \
+ ( ( ( ( uint64_t ) (prefix) ) << 32 ) | \
+ ( (type) << 24 ) | ( (index) << 16 ) | \
+ ( (offset) << 8 ) | ( (length) << 0 ) )
+
+#endif /* _IPXE_LLDP_H */
diff --git a/src/net/lldp.c b/src/net/lldp.c
new file mode 100644
index 0000000..72e3ecd
--- /dev/null
+++ b/src/net/lldp.c
@@ -0,0 +1,340 @@
+/*
+ * Copyright (C) 2023 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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 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; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** @file
+ *
+ * Link Layer Discovery Protocol
+ *
+ */
+
+#include <stdlib.h>
+#include <errno.h>
+#include <byteswap.h>
+#include <ipxe/iobuf.h>
+#include <ipxe/netdevice.h>
+#include <ipxe/if_ether.h>
+#include <ipxe/settings.h>
+#include <ipxe/lldp.h>
+
+/** An LLDP settings block */
+struct lldp_settings {
+ /** Reference counter */
+ struct refcnt refcnt;
+ /** Settings interface */
+ struct settings settings;
+ /** List of LLDP settings blocks */
+ struct list_head list;
+ /** Name */
+ const char *name;
+ /** LLDP data */
+ void *data;
+ /** Length of LLDP data */
+ size_t len;
+};
+
+/** LLDP settings scope */
+static const struct settings_scope lldp_settings_scope;
+
+/** List of LLDP settings blocks */
+static LIST_HEAD ( lldp_settings );
+
+/**
+ * Free LLDP settings block
+ *
+ * @v refcnt Reference counter
+ */
+static void lldp_free ( struct refcnt *refcnt ) {
+ struct lldp_settings *lldpset =
+ container_of ( refcnt, struct lldp_settings, refcnt );
+
+ DBGC ( lldpset, "LLDP %s freed\n", lldpset->name );
+ list_del ( &lldpset->list );
+ free ( lldpset->data );
+ free ( lldpset );
+}
+
+/**
+ * Find LLDP settings block
+ *
+ * @v netdev Network device
+ * @ret lldpset LLDP settings block
+ */
+static struct lldp_settings * lldp_find ( struct net_device *netdev ) {
+ struct lldp_settings *lldpset;
+
+ /* Find matching LLDP settings block */
+ list_for_each_entry ( lldpset, &lldp_settings, list ) {
+ if ( netdev_settings ( netdev ) == lldpset->settings.parent )
+ return lldpset;
+ }
+
+ return NULL;
+}
+
+/**
+ * Check applicability of LLDP setting
+ *
+ * @v settings Settings block
+ * @v setting Setting to fetch
+ * @ret applies Setting applies within this settings block
+ */
+static int lldp_applies ( struct settings *settings __unused,
+ const struct setting *setting ) {
+
+ return ( setting->scope == &lldp_settings_scope );
+}
+
+/**
+ * Fetch value of LLDP setting
+ *
+ * @v settings Settings block
+ * @v setting Setting to fetch
+ * @v buf Buffer to fill with setting data
+ * @v len Length of buffer
+ * @ret len Length of setting data, or negative error
+ */
+static int lldp_fetch ( struct settings *settings,
+ struct setting *setting,
+ void *buf, size_t len ) {
+ struct lldp_settings *lldpset =
+ container_of ( settings, struct lldp_settings, settings );
+ union {
+ uint32_t high;
+ uint8_t raw[4];
+ } tag_prefix;
+ uint32_t tag_low;
+ uint8_t tag_type;
+ uint8_t tag_index;
+ uint8_t tag_offset;
+ uint8_t tag_length;
+ const void *match;
+ const void *data;
+ size_t match_len;
+ size_t remaining;
+ const struct lldp_tlv *tlv;
+ unsigned int tlv_type_len;
+ unsigned int tlv_type;
+ unsigned int tlv_len;
+
+ /* Parse setting tag */
+ tag_prefix.high = htonl ( setting->tag >> 32 );
+ tag_low = setting->tag;
+ tag_type = ( tag_low >> 24 );
+ tag_index = ( tag_low >> 16 );
+ tag_offset = ( tag_low >> 8 );
+ tag_length = ( tag_low >> 0 );
+
+ /* Identify match prefix */
+ match_len = tag_offset;
+ if ( match_len > sizeof ( tag_prefix ) )
+ match_len = sizeof ( tag_prefix );
+ if ( ! tag_prefix.high )
+ match_len = 0;
+ match = &tag_prefix.raw[ sizeof ( tag_prefix ) - match_len ];
+
+ /* Locate matching TLV */
+ for ( data = lldpset->data, remaining = lldpset->len ; remaining ;
+ data += tlv_len, remaining -= tlv_len ) {
+
+ /* Parse TLV header */
+ if ( remaining < sizeof ( *tlv ) ) {
+ DBGC ( lldpset, "LLDP %s underlength TLV header\n",
+ lldpset->name );
+ DBGC_HDA ( lldpset, 0, data, remaining );
+ break;
+ }
+ tlv = data;
+ data += sizeof ( *tlv );
+ remaining -= sizeof ( *tlv );
+ tlv_type_len = ntohs ( tlv->type_len );
+ tlv_type = LLDP_TLV_TYPE ( tlv_type_len );
+ if ( tlv_type == LLDP_TYPE_END )
+ break;
+ tlv_len = LLDP_TLV_LEN ( tlv_type_len );
+ if ( remaining < tlv_len ) {
+ DBGC ( lldpset, "LLDP %s underlength TLV value\n",
+ lldpset->name );
+ DBGC_HDA ( lldpset, 0, data, remaining );
+ break;
+ }
+ DBGC2 ( lldpset, "LLDP %s found type %d:\n",
+ lldpset->name, tlv_type );
+ DBGC2_HDA ( lldpset, 0, data, tlv_len );
+
+ /* Check for matching tag type */
+ if ( tlv_type != tag_type )
+ continue;
+
+ /* Check for matching prefix */
+ if ( tlv_len < match_len )
+ continue;
+ if ( memcmp ( data, match, match_len ) != 0 )
+ continue;
+
+ /* Check for matching index */
+ if ( tag_index-- )
+ continue;
+
+ /* Skip offset */
+ if ( tlv_len < tag_offset )
+ return 0;
+ data += tag_offset;
+ tlv_len -= tag_offset;
+
+ /* Set type if not already specified */
+ if ( ! setting->type ) {
+ setting->type = ( tag_length ? &setting_type_hex :
+ &setting_type_string );
+ }
+
+ /* Extract value */
+ if ( tag_length && ( tlv_len > tag_length ) )
+ tlv_len = tag_length;
+ if ( len > tlv_len )
+ len = tlv_len;
+ memcpy ( buf, data, len );
+ return tlv_len;
+ }
+
+ return -ENOENT;
+}
+
+/** LLDP settings operations */
+static struct settings_operations lldp_settings_operations = {
+ .applies = lldp_applies,
+ .fetch = lldp_fetch,
+};
+
+/**
+ * Process LLDP packet
+ *
+ * @v iobuf I/O buffer
+ * @v netdev Network device
+ * @v ll_dest Link-layer destination address
+ * @v ll_source Link-layer source address
+ * @v flags Packet flags
+ * @ret rc Return status code
+ */
+static int lldp_rx ( struct io_buffer *iobuf, struct net_device *netdev,
+ const void *ll_dest, const void *ll_source,
+ unsigned int flags __unused ) {
+ struct lldp_settings *lldpset;
+ size_t len;
+ void *data;
+ int rc;
+
+ /* Find matching LLDP settings block */
+ lldpset = lldp_find ( netdev );
+ if ( ! lldpset ) {
+ DBGC ( netdev, "LLDP %s has no \"%s\" settings block\n",
+ netdev->name, LLDP_SETTINGS_NAME );
+ rc = -ENOENT;
+ goto err_find;
+ }
+
+ /* Create trimmed copy of received LLDP data */
+ len = iob_len ( iobuf );
+ data = malloc ( len );
+ if ( ! data ) {
+ rc = -ENOMEM;
+ goto err_alloc;
+ }
+ memcpy ( data, iobuf->data, len );
+
+ /* Free any existing LLDP data */
+ free ( lldpset->data );
+
+ /* Transfer data to LLDP settings block */
+ lldpset->data = data;
+ lldpset->len = len;
+ data = NULL;
+ DBGC2 ( lldpset, "LLDP %s src %s ",
+ lldpset->name, netdev->ll_protocol->ntoa ( ll_source ) );
+ DBGC2 ( lldpset, "dst %s\n", netdev->ll_protocol->ntoa ( ll_dest ) );
+ DBGC2_HDA ( lldpset, 0, lldpset->data, lldpset->len );
+
+ /* Success */
+ rc = 0;
+
+ free ( data );
+ err_alloc:
+ err_find:
+ free_iob ( iobuf );
+ return rc;
+}
+
+/** LLDP protocol */
+struct net_protocol lldp_protocol __net_protocol = {
+ .name = "LLDP",
+ .net_proto = htons ( ETH_P_LLDP ),
+ .rx = lldp_rx,
+};
+
+/**
+ * Create LLDP settings block
+ *
+ * @v netdev Network device
+ * @ret rc Return status code
+ */
+static int lldp_probe ( struct net_device *netdev ) {
+ struct lldp_settings *lldpset;
+ int rc;
+
+ /* Allocate LLDP settings block */
+ lldpset = zalloc ( sizeof ( *lldpset ) );
+ if ( ! lldpset ) {
+ rc = -ENOMEM;
+ goto err_alloc;
+ }
+ ref_init ( &lldpset->refcnt, lldp_free );
+ settings_init ( &lldpset->settings, &lldp_settings_operations,
+ &lldpset->refcnt, &lldp_settings_scope );
+ list_add_tail ( &lldpset->list, &lldp_settings );
+ lldpset->name = netdev->name;
+
+ /* Register settings */
+ if ( ( rc = register_settings ( &lldpset->settings, netdev_settings ( netdev ),
+ LLDP_SETTINGS_NAME ) ) != 0 ) {
+ DBGC ( lldpset, "LLDP %s could not register settings: %s\n",
+ lldpset->name, strerror ( rc ) );
+ goto err_register;
+ }
+ DBGC ( lldpset, "LLDP %s registered\n", lldpset->name );
+
+ ref_put ( &lldpset->refcnt );
+ return 0;
+
+ unregister_settings ( &lldpset->settings );
+ err_register:
+ ref_put ( &lldpset->refcnt );
+ err_alloc:
+ return rc;
+}
+
+/** LLDP driver */
+struct net_driver lldp_driver __net_driver = {
+ .name = "LLDP",
+ .probe = lldp_probe,
+};
