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 $SDK"
  94         make -C osx pkg
  95
  96     With recent SDK, you don't need to specify an alternate SDK. They
  97     are organized in a way that should enable compatibility with older
  98     versions of OSX:
  99
 100         mkdir build && cd build
 101         ../configure --prefix=/usr/local --localstatedir=/var --sysconfdir=/private/etc --with-embedded-libevent \
 102            --without-snmp \
 103            CFLAGS="-mmacosx-version-min=10.9" \
 104            LDFLAGS="-mmacosx-version-min=10.9"
 105         make -C osx pkg
 106
 107     You can check with `otool -l` that you got what you expected in
 108     term of supported versions.
 109
 110 If you don't follow the above procedures, you will have to create the
 111 user/group `_lldpd`. Have a look at how this is done in
 112 `osx/scripts/postinstall`.
 113
 114 Installation (Android)
 115 ----------------------
 116
 117 You need to download [Android NDK][]. Once unpacked, you can generate
 118 a toolchain using the following command:
 119
 120     ./build/tools/make-standalone-toolchain.sh \
 121         --platform=android-9 \
 122         --arch=arm \
 123         --install-dir=../android-toolchain
 124     export TOOLCHAIN=$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=arm-linux-androideabi \
 132         --with-sysroot=$TOOLCHAIN/sysroot \
 133         --prefix=/system \
 134         --sbindir=/system/bin
 135     make
 136     make install DESTDIR=$PWD/install
 137
 138 Then, copy `install/system/bin/*` to `/system/bin` on the target
 139 system and `install/system/lib/*.so*` to `/system/lib` on the target
 140 system.
 141
 142 [Android NDK]: http://developer.android.com/tools/sdk/ndk/index.html
 143
 144 Usage
 145 -----
 146
 147 lldpd also implements CDP (Cisco Discovery Protocol), FDP (Foundry
 148 Discovery Protocol), SONMP (Nortel Discovery Protocol) and EDP
 149 (Extreme Discovery Protocol). However, recent versions of IOS should
 150 support LLDP and most Extreme stuff support LLDP. When a EDP, CDP or
 151 SONMP frame is received on a given interface, lldpd starts sending
 152 EDP, CDP, FDP or SONMP frame on this interface. Informations collected
 153 through EDP/CDP/FDP/SONMP are integrated with other informations and
 154 can be queried with `lldpcli` or through SNMP.
 155
 156 More information:
 157  * http://en.wikipedia.org/wiki/Link_Layer_Discovery_Protocol
 158  * http://standards.ieee.org/getieee802/download/802.1AB-2005.pdf
 159  * http://wiki.wireshark.org/LinkLayerDiscoveryProtocol
 160
 161 Compatibility with older kernels
 162 --------------------------------
 163
 164 If you have a kernel older than Linux 2.6.39, you need to compile
 165 lldpd with `--enable-oldies` to enable some compatibility functions:
 166 otherwise, lldpd will only rely on Netlink to receive bridge, bond and
 167 VLAN information.
 168
 169 For bonding, you need 2.6.24 (in previous version, PACKET_ORIGDEV
 170 affected only non multicast packets). See:
 171
 172  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=80feaacb8a6400a9540a961b6743c69a5896b937
 173  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=8032b46489e50ef8f3992159abd0349b5b8e476c
 174
 175 Otherwise, a packet received on a bond will be affected to all
 176 interfaces of the bond. In this case, lldpd will affect a received
 177 randomly to one of the interface (so a neighbor may be affected to the
 178 wrong interface).
 179
 180 On 2.6.27, we are able to receive packets on real interface for enslaved
 181 devices. This allows one to get neighbor information on active/backup
 182 bonds. Without the 2.6.27, lldpd won't receive any information on
 183 inactive slaves. Here are the patchs (thanks to Joe Eykholt):
 184
 185  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=0d7a3681232f545c6a59f77e60f7667673ef0e93
 186  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=cc9bd5cebc0825e0fabc0186ab85806a0891104f
 187  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=f982307f22db96201e41540295f24e8dcc10c78f
 188
 189 On FreeBSD, only a recent 9 kernel (9.1 or more recent) will allow to
 190 send LLDP frames on enslaved devices. See this bug report for more
 191 information:
 192
 193  * http://www.freebsd.org/cgi/query-pr.cgi?pr=138620
 194
 195 Some devices (notably Cisco IOS) send frames tagged with the native
 196 VLAN while they should send them untagged. If your network card does
 197 not support accelerated VLAN, you will receive those frames as long as
 198 the corresponding interface exists (see below). However, if your
 199 network card handles VLAN encapsulation/decapsulation (check with
 200 `ethtool -k`), you need a recent kernel to be able to receive those
 201 frames without listening on all available VLAN. Starting from Linux
 202 2.6.27, lldpd is able to capture VLAN frames when VLAN acceleration is
 203 supported by the network card. Here is the patch:
 204
 205  * http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=bc1d0411b804ad190cdadabac48a10067f17b9e6
 206
 207 On some other versions, frames are sent on VLAN 1. If this is not the
 208 native VLAN and if your network card support accelerated VLAN, you
 209 need to subscribe to this VLAN as well. The Linux kernel does not
 210 provide any interface for this. The easiest way is to create the VLAN
 211 for each port:
 212
 213     ip link add link eth0 name eth0.1 type vlan id 1
 214     ip link set up dev eth0.1
 215
 216 You can check both cases using tcpdump:
 217
 218     tcpdump -epni eth0 ether host 01:80:c2:00:00:0e
 219     tcpdump -eni eth0 ether host 01:80:c2:00:00:0e
 220
 221 If the first command does not display received LLDP packets but the
 222 second one does, LLDP packets are likely encapsulated into a VLAN:
 223
 224     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
 225
 226 In this case, just create VLAN 1 will fix the situation. There are
 227 other solutions:
 228
 229  1. Disable VLAN acceleration on the receive side (`ethtool -K eth0
 230     rxvlan off`) but this may or may not work. Check if there are
 231     similar properties that could apply with `ethtool -k eth0`.
 232  2. Put the interface in promiscuous mode with `ip link set
 233     promisc on dev eth0`.
 234
 235 The last solution can be done directly by `lldpd` (on Linux only) by
 236 using the option `configure system interface promiscuous`.
 237
 238 On modern networks, the performance impact should be nonexistent.
 239
 240 Development
 241 -----------
 242
 243 During development, you may want to execute lldpd at its current
 244 location instead of doing `make install`. The correct way to do this is
 245 to issue the following command:
 246
 247     sudo libtool execute src/daemon/lldpd -L $PWD/src/client/lldpcli -d
 248
 249 You can append any further arguments. If lldpd is unable to find
 250 `lldpcli` it will start in an unconfigured mode and won't send or
 251 accept LLDP frames.
 252
 253 You can use [afl](http://lcamtuf.coredump.cx/afl/) to test some
 254 aspects of lldpd. To test frame decoding, you can do something like
 255 that:
 256
 257     export AFL_USE_ASAN=1 # only on 32bit arch
 258     ./configure CC=afl-gcc
 259     make clean check
 260     cd tests
 261     mkdir inputs
 262     mv *.pcap inputs
 263     afl-fuzz -i inputs -o outputs ./decode @@
 264
 265 There is a general test suite with `make check`. It's also possible to
 266 run integration tests. They need [py.test](http://pytest.org/latest/)
 267 and rely on Linux containers to be executed.
 268
 269 To enable code coverage, use:
 270
 271     ../configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var \
 272                  --enable-sanitizers --enable-gcov --with-snmp \
 273                  CFLAGS="-O0 -g"
 274     make
 275     make check
 276     # maybe, run integration tests
 277     lcov --base-directory $PWD/src/lib \
 278          --directory src --capture --output-file gcov.info
 279     genhtml gcov.info --output-directory coverage
 280
 281 Embedding
 282 ---------
 283
 284 To embed lldpd into an existing system, there are two point of entries:
 285
 286  1. If your system does not use standard Linux interface, you can
 287     support additional interfaces by implementing the appropriate
 288     `struct lldpd_ops`. You can look at
 289     `src/daemon/interfaces-linux.c` for examples. Also, have a look at
 290     `interfaces_update()` which is responsible for discovering and
 291     registering interfaces.
 292
 293  2. `lldpcli` provides a convenient way to query `lldpd`. It also
 294     comes with various outputs, including XML which allows one to
 295     parse its output for integration and automation purpose. Another
 296     way is to use SNMP support. A third way is to write your own
 297     controller using `liblldpctl.so`. Its API is described in
 298     `src/lib/lldpctl.h`. The custom binary protocol between
 299     `liblldpctl.so` and `lldpd` is not stable. Therefore, the library
 300     should always be shipped with `lldpd`. On the other hand, programs
 301     using `liblldpctl.so` can rely on the classic ABI rules.
 302
 303 Troubleshooting
 304 ---------------
 305
 306 You can use `tcpdump` to look after the packets received and send by
 307 `lldpd`. To look after LLDPU, use:
 308
 309     tcpdump -s0 -vv -pni eth0 ether dst 01:80:c2:00:00:0e
 310
 311 Intel X710 cards may handle LLDP themselves, intercepting any incoming
 312 packets. If you don't see anything through `tcpdump`, check if you
 313 have such a card (with `lspci`) and stop the embedded LLDP daemon:
 314
 315     for f in /sys/kernel/debug/i40e/*/command; do
 316         echo lldp stop > $f
 317     done
 318
 319 License
 320 -------
 321
 322 lldpd is distributed under the ISC license:
 323
 324  > Permission to use, copy, modify, and/or distribute this software for any
 325  > purpose with or without fee is hereby granted, provided that the above
 326  > copyright notice and this permission notice appear in all copies.
 327  >
 328  > THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 329  > WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 330  > MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 331  > ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 332  > WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 333  > ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 334  > OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 335
 336 Also, `lldpcli` will be linked to GNU Readline (which is GPL licensed)
 337 if available. To avoid this, use `--without-readline` as a configure
 338 option.