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