README.md

   1 lldpd: implementation of IEEE 802.1ab (LLDP)
   2 ============================================
   3
   4 [![Build Status](https://secure.travis-ci.org/vincentbernat/lldpd.png?branch=master)](http://travis-ci.org/vincentbernat/lldpd)
   5
   6   http://vincentbernat.github.com/lldpd/
   7
   8 Features
   9 --------
  10
  11 LLDP (Link Layer Discovery Protocol) is an industry standard protocol
  12 designed to supplant proprietary Link-Layer protocols such as
  13 Extreme's EDP (Extreme Discovery Protocol) and CDP (Cisco Discovery
  14 Protocol). The goal of LLDP is to provide an inter-vendor compatible
  15 mechanism to deliver Link-Layer notifications to adjacent network
  16 devices.
  17
  18 lldpd implements both reception and sending. It also implements an
  19 SNMP subagent for net-snmp to get local and remote LLDP
  20 information. The LLDP-MIB is partially implemented but the most useful
  21 tables are here. lldpd also partially implements LLDP-MED.
  22
  23 lldpd supports bridge, vlan and bonding.
  24
  25 The following OS are supported:
  26
  27  * FreeBSD
  28  * GNU/Linux
  29  * macOS
  30  * NetBSD
  31  * OpenBSD
  32  * Solaris
  33
  34 Windows is not supported but you can use
  35 [WinLLDPService](https://github.com/raspi/WinLLDPService/) as a
  36 transmit-only agent.
  37
  38 Installation
  39 ------------
  40
  41 For general instructions [prefer the
  42 website](http://vincentbernat.github.io/lldpd/installation.html),
  43 including building from released tarballs.
  44
  45 To compile lldpd from Git, use the following commands:
  46
  47     ./autogen.sh
  48     ./configure
  49     make
  50     sudo make install
  51
  52 lldpd uses privilege separation to increase its security. Two
  53 processes, one running as root and doing minimal stuff and the other
  54 running as an unprivileged user into a chroot doing most of the stuff,
  55 are cooperating. You need to create a user called `_lldpd` in a group
  56 `_lldpd` (this can be change with `./configure`). You also need to
  57 create an empty directory `/usr/local/var/run/lldpd` (it needs to be
  58 owned by root, not `_lldpd`!). If you get fuzzy timestamps from
  59 syslog, copy `/etc/locatime` into the chroot.
  60
  61 `lldpcli` lets one query information collected through the command
  62 line. If you don't want to run it as root, just install it setuid or
  63 setgid `_lldpd`.
  64
  65 Installation (macOS)
  66 -----------------------
  67
  68 The same procedure as above applies for macOS. However, there are
  69 simpler alternatives:
  70
  71  1. Use [Homebrew](https://brew.sh):
  72
  73         brew install lldpd
  74         # Or, for the latest version:
  75         brew install https://raw.github.com/vincentbernat/lldpd/master/osx/lldpd.rb
  76
  77  2. Build an macOS installer package which should work on the same
  78     version of macOS:
  79
  80         mkdir build && cd build
  81         ../configure --prefix=/usr/local --localstatedir=/var --sysconfdir=/private/etc --with-embedded-libevent \
  82             --without-snmp
  83         make -C osx pkg
  84
  85     If you want to compile for an older version of macOS, you need
  86     to find the right SDK and issues commands like those:
  87
  88         SDK=/Developer/SDKs/MacOSX10.6.sdk
  89         mkdir build && cd build
  90         ../configure --prefix=/usr/local --localstatedir=/var --sysconfdir=/private/etc --with-embedded-libevent \
  91            --without-snmp \
  92            CFLAGS="-mmacosx-version-min=10.6 -isysroot $SDK" \
  93            LDFLAGS="-mmacosx-version-min=10.6 -isysroot $SDK"
  94         make -C osx pkg
  95
  96     With recent SDK, you don't need to specify an alternate SDK. They
  97     are organized in a way that should enable compatibility with older
  98     versions of OSX:
  99
 100         mkdir build && cd build
 101         ../configure --prefix=/usr/local --localstatedir=/var --sysconfdir=/private/etc --with-embedded-libevent \
 102            --without-snmp \
 103            CFLAGS="-mmacosx-version-min=10.9" \
 104            LDFLAGS="-mmacosx-version-min=10.9"
 105         make -C osx pkg
 106
 107     You can check with `otool -l` that you got what you expected in
 108     term of supported versions.
 109
 110 If you don't follow the above procedures, you will have to create the
 111 user/group `_lldpd`. Have a look at how this is done in
 112 `osx/scripts/postinstall`.
 113
 114 Installation (Android)
 115 ----------------------
 116
 117 You need to download [Android NDK][]. Once unpacked, you can generate
 118 a toolchain using the following command (for ARM64):
 119
 120     ./build/tools/make-standalone-toolchain.sh \
 121         --platform=android-24 \
 122         --arch=arm64 \
 123         --install-dir=../android-toolchain
 124     export TOOLCHAIN=$PWD/../android-toolchain
 125
 126 Then, you can build `lldpd` with the following commands:
 127
 128     mkdir build && cd build
 129     export PATH=$PATH:$TOOLCHAIN/bin
 130     ../configure \
 131         --host=arm64-linux-androideabi \
 132         --with-sysroot=$TOOLCHAIN/sysroot \
 133         --prefix=/system \
 134         --sbindir=/system/bin \
 135         --runstatedir=/data/data/lldpd \
 136         --with-privsep-user=root \
 137         --with-privsep-group=root
 138     make
 139     make install DESTDIR=$PWD/install
 140
 141 Then, copy `install/system/bin/*` to `/system/bin` on the target
 142 system and `install/system/lib/*.so*` to `/system/lib` on the target
 143 system. You may need to create `/data/data/lldpd` as well.
 144
 145 [Android NDK]: http://developer.android.com/tools/sdk/ndk/index.html
 146
 147 Usage
 148 -----
 149
 150 lldpd also implements CDP (Cisco Discovery Protocol), FDP (Foundry
 151 Discovery Protocol), SONMP (Nortel Discovery Protocol) and EDP
 152 (Extreme Discovery Protocol). However, recent versions of IOS should
 153 support LLDP and most Extreme stuff support LLDP. When a EDP, CDP or
 154 SONMP frame is received on a given interface, lldpd starts sending
 155 EDP, CDP, FDP or SONMP frame on this interface. Informations collected
 156 through EDP/CDP/FDP/SONMP are integrated with other informations and
 157 can be queried with `lldpcli` or through SNMP.
 158
 159 More information:
 160  * http://en.wikipedia.org/wiki/Link_Layer_Discovery_Protocol
 161  * http://standards.ieee.org/getieee802/download/802.1AB-2005.pdf
 162  * http://wiki.wireshark.org/LinkLayerDiscoveryProtocol
 163
 164 Compatibility with older kernels
 165 --------------------------------
 166
 167 If you have a kernel older than Linux 2.6.39, you need to compile
 168 lldpd with `--enable-oldies` to enable some compatibility functions:
 169 otherwise, lldpd will only rely on Netlink to receive bridge, bond and
 170 VLAN information.
 171
 172 For bonding, you need 2.6.24 (in previous version, PACKET_ORIGDEV
 173 affected only non multicast packets). See:
 174
 175  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=80feaacb8a6400a9540a961b6743c69a5896b937
 176  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=8032b46489e50ef8f3992159abd0349b5b8e476c
 177
 178 Otherwise, a packet received on a bond will be affected to all
 179 interfaces of the bond. In this case, lldpd will affect a received
 180 randomly to one of the interface (so a neighbor may be affected to the
 181 wrong interface).
 182
 183 On 2.6.27, we are able to receive packets on real interface for enslaved
 184 devices. This allows one to get neighbor information on active/backup
 185 bonds. Without the 2.6.27, lldpd won't receive any information on
 186 inactive slaves. Here are the patchs (thanks to Joe Eykholt):
 187
 188  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=0d7a3681232f545c6a59f77e60f7667673ef0e93
 189  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=cc9bd5cebc0825e0fabc0186ab85806a0891104f
 190  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=f982307f22db96201e41540295f24e8dcc10c78f
 191
 192 On FreeBSD, only a recent 9 kernel (9.1 or more recent) will allow to
 193 send LLDP frames on enslaved devices. See this bug report for more
 194 information:
 195
 196  * http://www.freebsd.org/cgi/query-pr.cgi?pr=138620
 197
 198 Some devices (notably Cisco IOS) send frames tagged with the native
 199 VLAN while they should send them untagged. If your network card does
 200 not support accelerated VLAN, you will receive those frames as long as
 201 the corresponding interface exists (see below). However, if your
 202 network card handles VLAN encapsulation/decapsulation (check with
 203 `ethtool -k`), you need a recent kernel to be able to receive those
 204 frames without listening on all available VLAN. Starting from Linux
 205 2.6.27, lldpd is able to capture VLAN frames when VLAN acceleration is
 206 supported by the network card. Here is the patch:
 207
 208  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=bc1d0411b804ad190cdadabac48a10067f17b9e6
 209
 210 On some other versions, frames are sent on VLAN 1. If this is not the
 211 native VLAN and if your network card support accelerated VLAN, you
 212 need to subscribe to this VLAN as well. The Linux kernel does not
 213 provide any interface for this. The easiest way is to create the VLAN
 214 for each port:
 215
 216     ip link add link eth0 name eth0.1 type vlan id 1
 217     ip link set up dev eth0.1
 218
 219 You can check both cases using tcpdump:
 220
 221     tcpdump -epni eth0 ether host 01:80:c2:00:00:0e
 222     tcpdump -eni eth0 ether host 01:80:c2:00:00:0e
 223
 224 If the first command does not display received LLDP packets but the
 225 second one does, LLDP packets are likely encapsulated into a VLAN:
 226
 227     10:54:06.431154 f0:29:29:1d:7c:01 > 01:80:c2:00:00:0e, ethertype 802.1Q (0x8100), length 363: vlan 1, p 7, ethertype LLDP, LLDP, name SW-APP-D07.VTY, length 345
 228
 229 In this case, just create VLAN 1 will fix the situation. There are
 230 other solutions:
 231
 232  1. Disable VLAN acceleration on the receive side (`ethtool -K eth0
 233     rxvlan off`) but this may or may not work. Check if there are
 234     similar properties that could apply with `ethtool -k eth0`.
 235  2. Put the interface in promiscuous mode with `ip link set
 236     promisc on dev eth0`.
 237
 238 The last solution can be done directly by `lldpd` (on Linux only) by
 239 using the option `configure system interface promiscuous`.
 240
 241 On modern networks, the performance impact should be nonexistent.
 242
 243 Development
 244 -----------
 245
 246 During development, you may want to execute lldpd at its current
 247 location instead of doing `make install`. The correct way to do this is
 248 to issue the following command:
 249
 250     sudo libtool execute src/daemon/lldpd -L $PWD/src/client/lldpcli -d
 251
 252 You can append any further arguments. If lldpd is unable to find
 253 `lldpcli` it will start in an unconfigured mode and won't send or
 254 accept LLDP frames.
 255
 256 You can use [afl](http://lcamtuf.coredump.cx/afl/) to test some
 257 aspects of lldpd. To test frame decoding, you can do something like
 258 that:
 259
 260     export AFL_USE_ASAN=1 # only on 32bit arch
 261     ./configure CC=afl-gcc
 262     make clean check
 263     cd tests
 264     mkdir inputs
 265     mv *.pcap inputs
 266     afl-fuzz -i inputs -o outputs ./decode @@
 267
 268 There is a general test suite with `make check`. It's also possible to
 269 run integration tests. They need [py.test](http://pytest.org/latest/)
 270 and rely on Linux containers to be executed.
 271
 272 To enable code coverage, use:
 273
 274     ../configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var \
 275                  --enable-sanitizers --enable-gcov --with-snmp \
 276                  CFLAGS="-O0 -g"
 277     make
 278     make check
 279     # maybe, run integration tests
 280     lcov --base-directory $PWD/src/lib \
 281          --directory src --capture --output-file gcov.info
 282     genhtml gcov.info --output-directory coverage
 283
 284 Embedding
 285 ---------
 286
 287 To embed lldpd into an existing system, there are two point of entries:
 288
 289  1. If your system does not use standard Linux interface, you can
 290     support additional interfaces by implementing the appropriate
 291     `struct lldpd_ops`. You can look at
 292     `src/daemon/interfaces-linux.c` for examples. Also, have a look at
 293     `interfaces_update()` which is responsible for discovering and
 294     registering interfaces.
 295
 296  2. `lldpcli` provides a convenient way to query `lldpd`. It also
 297     comes with various outputs, including XML which allows one to
 298     parse its output for integration and automation purpose. Another
 299     way is to use SNMP support. A third way is to write your own
 300     controller using `liblldpctl.so`. Its API is described in
 301     `src/lib/lldpctl.h`. The custom binary protocol between
 302     `liblldpctl.so` and `lldpd` is not stable. Therefore, the library
 303     should always be shipped with `lldpd`. On the other hand, programs
 304     using `liblldpctl.so` can rely on the classic ABI rules.
 305
 306 Troubleshooting
 307 ---------------
 308
 309 You can use `tcpdump` to look after the packets received and send by
 310 `lldpd`. To look after LLDPU, use:
 311
 312     tcpdump -s0 -vv -pni eth0 ether dst 01:80:c2:00:00:0e
 313
 314 Intel X710 cards may handle LLDP themselves, intercepting any incoming
 315 packets. If you don't see anything through `tcpdump`, check if you
 316 have such a card (with `lspci`) and stop the embedded LLDP daemon:
 317
 318     for f in /sys/kernel/debug/i40e/*/command; do
 319         echo lldp stop > $f
 320     done
 321
 322 License
 323 -------
 324
 325 lldpd is distributed under the ISC license:
 326
 327  > Permission to use, copy, modify, and/or distribute this software for any
 328  > purpose with or without fee is hereby granted, provided that the above
 329  > copyright notice and this permission notice appear in all copies.
 330  >
 331  > THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 332  > WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 333  > MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 334  > ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 335  > WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 336  > ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 337  > OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 338
 339 Also, `lldpcli` will be linked to GNU Readline (which is GPL licensed)
 340 if available. To avoid this, use `--without-readline` as a configure
 341 option.