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