README
1 dhcpcd - DHCP client daemon
2 Copyright (c) 2006-2015 Roy Marples <roy (a] marples.name>
3
4
5 Installation
6 ------------
7 ./configure; make; make install
8 man dhcpcd for command line options
9 man dhcpcd.conf for configuration options
10 man dhcpcd-run-hooks to learn how to hook scripts into dhcpcd events
11
12
13 Notes
14 -----
15 If you're cross compiling you may need set the platform if OS is different
16 from the host.
17 --target=sparc-sun-netbsd5.0
18
19 If you're building for an MMU-less system where fork() does not work, you
20 should ./configure --disable-fork.
21 This also puts the --no-background flag on and stops the --background flag
22 from working.
23
24 You can change the default dirs with these knobs.
25 For example, to satisfy FHS compliance you would do this:-
26 ./configure --libexecdir=/lib/dhcpcd dbdir=/var/lib/dhcpcd
27
28 We now default to using -std=c99. For 64-bit linux, this always works, but
29 for 32-bit linux it requires either gnu99 or a patch to asm/types.h.
30 Most distros patch linux headers so this should work fine.
31 linux-2.6.24 finally ships with a working 32-bit header.
32 If your linux headers are older, or your distro hasn't patched them you can
33 set CSTD=gnu99 to work around this.
34
35 Some BSD systems do not allow the manipulation of automatically added subnet
36 routes. You can find discussion here:
37 http://mail-index.netbsd.org/tech-net/2008/12/03/msg000896.html
38 BSD systems where this has been fixed or is known to work are:
39 NetBSD-5.0
40 FreeBSD-10.0
41
42 Some BSD systems protect against IPv6 NS/NA messages by ensuring that the
43 source address matches a prefix on the recieved by a RA message.
44 This is an error as the correct check is for on-link prefixes as the
45 kernel may not be handling RA itself.
46 BSD systems where this has been fixed or is known to work are:
47 NetBSD-7.0
48 OpenBSD-5.0
49 patch submitted against FreeBSD-10.0
50
51 Some BSD systems do not announce IPv6 address flag changes, such as
52 IN6_IFF_TENTATIVE, IN6_IFF_DUPLICATED, etc. On these systems,
53 dhcpcd will poll a freshly added address until either IN6_IFF_TENTATIVE is
54 cleared or IN6_IFF_DUPLICATED is set and take action accordingly.
55 BSD systems where this has been fixed or is known to work are:
56 NetBSD-7.0
57
58 Some BSD systems do not announce cached neighbour route changes based
59 on reachability to userland. For such systems, IPv6 routers will always
60 be assumed to be reachable until they either stop being a router or expire.
61 BSD systems where this has been fixed or is known to work are:
62 NetBSD-7.99.3
63
64 Linux prior to 3.17 won't allow userland to manage IPv6 temporary addresses.
65 Either upgrade or don't allow dhcpcd to manage the RA,
66 so don't set either "ipv6ra_own" or "slaac private" in dhcpcd.conf if you
67 want to have working IPv6 temporary addresses.
68 SLAAC private addresses are just as private, just stable.
69
70 ArchLinux presently sanitises all kernel headers to the latest version
71 regardless of the version for your CPU. As such, Arch presently ships a
72 3.12 kernel with 3.17 headers which claim that it suppors temporary address
73 management and no automatic prefix route generation, both of which are
74 obviously false. You will have to patch support either in the kernel or
75 out of the headers (or dhcpcd itself) to have correct operation.
76
77 We try and detect how dhcpcd should interact with system services at runtime.
78 If we cannot auto-detect how do to this, or it is wrong then
79 you can change this by passing shell commands to --serviceexists,
80 --servicecmd and optionally --servicestatus to ./configure or overriding
81 the service variables in a hook.
82
83 Some systems have /dev management systems and some of these like to rename
84 interfaces. As this system would listen in the same way as dhcpcd to new
85 interface arrivals, dhcpcd needs to listen to the /dev management sytem
86 instead of the kernel. However, if the /dev management system breaks, stops
87 working, or changes to a new one, dhcpcd should still try and continue to work.
88 To facilitate this, dhcpcd allows a plugin to load to instruct dhcpcd when it
89 can use an interface. As of the time of writing only udev support is included.
90 You can disable this with --without-dev, or without-udev
91
92 To shrink dhcpcd you can disable IPv4 or IPv6:
93 --disable-inet
94 --disable-inet6
95
96 You can also move the embedded extended configuration from the dhcpcd binary
97 to an external file (LIBEXECDIR/dhcpcd-definitions.conf)
98 --disable-embedded
99 If dhcpcd cannot load this file at runtime, dhcpcd will work but will not be
100 able to decode any DHCP/DHCPv6 options that are not defined by the user
101 in /etc/dhcpcd.conf.
102
103 To prepare dhcpcd for import into a platform source tree (like NetBSD)
104 you can use the make import target to create /tmp/dhcpcd-$version and
105 populate it with all the source files and hooks needed.
106 In this instance, you may wish to disable some configured tests when
107 the binary has to run on older versions which lack support, such as getline.
108 ./configure --without-getline
109
110 Building for distribution (ie making a dhcpcd source tarball) now requires
111 gmake-4 or any BSD make.
112
113
114 Hooks
115 -----
116 Not all the hooks in dhcpcd-hooks are installed by default.
117 By default we install 01-test, 02-dump, 10-mtu, 10-wpa_supplicant,
118 15-timezone, 20-resolv.conf, 29-lookup-hostname and 30-hostname.
119 The default dhcpcd.conf disables the lookup-hostname hook by default.
120 The configure program attempts to find hooks for systems you have installed.
121 To add more simply
122 ./configure -with-hook=ntp.conf
123
124 Some system services expose the name of the service we are in,
125 by default dhcpcd will pick RC_SVCNAME from the environment.
126 You can override this in CPPFLAGS+= -DRC_SVCNAME="YOUR_SVCNAME".
127 This is important because dhcpcd will scrub the environment aside from $PATH
128 before running hooks.
129 This variable could be used to facilitate service re-entry so this chain could
130 happen in a custom OS hook:
131 dhcpcd service marked inactive && dhcpcd service starts
132 dependant services are not started because dhcpcd is inactive (not stopped)
133 dhcpcd hook tests $if_oneup && $if_ipwaited
134 if true, mark the dhcpcd service as started and then start dependencies
135 if false and the dhcpcd service was previously started, mark as inactive and
136 stop any dependant services.
137
138
139 Compatibility
140 -------------
141 dhcpcd-5.0 is only fully command line compatible with dhcpcd-4.0
142 For compatibility with older versions, use dhcpcd-4.0
143
144
145 ChangeLog
146 ---------
147 We no longer supply a ChangeLog.
148 However, you're more than welcome to read the commit log at
149 http://roy.marples.name/projects/dhcpcd/timeline/
150