SEO

This patch adds a 'no-link-on "interface" [, "interface", ...];' option
to dhclient.conf. This is e.g. useful in order to skip wireless dhcp
when there's a cable plugged into the ethernet card (on a notebook).

$ cat /etc/dhclient.conf
initial-interval 1;
request subnet-mask, broadcast-address, routers, domain-name,
domain-name-servers, host-name;

interface "ath0" {
no-link-on "rl0";
}
interface "rl0" {
link-timeout 0;
}
$ sudo dhclient ath0
Found link on rl0, skipping ath0
$

It's a quick hack; works for me, but should be tested.

Index: clparse.c
================================================== =================
RCS file: /cvs/src/sbin/dhclient/clparse.c,v
retrieving revision 1.34
diff -u -r1.34 clparse.c
--- clparse.c 14 Feb 2007 23:19:26 -0000 1.34
+++ clparse.c 17 Jun 2007 15:33:23 -0000
@@ -198,6 +198,9 @@
sizeof(config->required_options));
parse_option_list(cfile, config->required_options);
return;
+ case TOK_NO_LINK_ON:
+ parse_string_list(cfile, &config->no_link_on, 1);
+ return;
case TOK_LINK_TIMEOUT:
parse_lease_time(cfile, &config->link_timeout);
return;
@@ -740,7 +743,7 @@
do {
token = next_token(&val, cfile);
if (token != TOK_STRING) {
- parse_warn("Expecting media options.");
+ parse_warn("Invalid options. Expecting strings.");
skip_to_semi(cfile);
return;
}
Index: conflex.c
================================================== =================
RCS file: /cvs/src/sbin/dhclient/conflex.c,v
retrieving revision 1.13
diff -u -r1.13 conflex.c
--- conflex.c 17 Dec 2006 17:41:56 -0000 1.13
+++ conflex.c 17 Jun 2007 15:33:23 -0000
@@ -330,6 +330,7 @@
{ "link-timeout", TOK_LINK_TIMEOUT },
{ "media", TOK_MEDIA },
{ "medium", TOK_MEDIUM },
+ { "no-link-on", TOK_NO_LINK_ON },
{ "option", TOK_OPTION },
{ "prepend", TOK_PREPEND },
{ "rebind", TOK_REBIND },
Index: dhclient.c
================================================== =================
RCS file: /cvs/src/sbin/dhclient/dhclient.c,v
retrieving revision 1.111
diff -u -r1.111 dhclient.c
--- dhclient.c 25 Feb 2007 18:10:43 -0000 1.111
+++ dhclient.c 17 Jun 2007 15:33:24 -0000
@@ -242,6 +242,7 @@
int ch, fd, quiet = 0, i = 0, pipe_fd[2];
extern char *__progname;
struct passwd *pw;
+ struct string_list *nlo;

/* Initially, log errors to stderr as well as to syslogd. */
openlog(__progname, LOG_PID | LOG_NDELAY, DHCPD_LOG_FACILITY);
@@ -304,6 +305,17 @@
inaddr_any.s_addr = INADDR_ANY;

read_client_conf();
+
+ nlo = config->no_link_on;
+ if (nlo != NULL) {
+ do {
+ if (interface_link_status(nlo->string)) {
+ fprintf(stderr, "Found link on %s, skipping %s\n",
+ nlo->string, ifi->name);
+ exit(1);
+ }
+ } while ((nlo = nlo->next) != NULL);
+ }

if (!interface_link_status(ifi->name)) {
int linkstat = interface_link_forceup(ifi->name);
Index: dhclient.conf.5
================================================== =================
RCS file: /cvs/src/sbin/dhclient/dhclient.conf.5,v
retrieving revision 1.12
diff -u -r1.12 dhclient.conf.5
--- dhclient.conf.5 18 Dec 2006 19:11:44 -0000 1.12
+++ dhclient.conf.5 17 Jun 2007 15:33:24 -0000
@@ -161,6 +161,14 @@
out.
The default value is 10 seconds, but the special value 0 requests that dhclient
not wait for a link state change before timing out.
+.It Xo
+.Ic no-link-on Ar \&"interface\&"
+.Oo , Ar \&"interface\&" , ... Oc ;
+.Xc
+The
+.Ic no-link-on
+statement causes the client to only send requests if the listed interfaces do
+not have an interface link.
.El
.Sh LEASE REQUIREMENTS AND REQUESTS
The DHCP protocol allows the client to request that the server send it
Index: dhcpd.h
================================================== =================
RCS file: /cvs/src/sbin/dhclient/dhcpd.h,v
retrieving revision 1.65
diff -u -r1.65 dhcpd.h
--- dhcpd.h 25 Feb 2007 16:27:20 -0000 1.65
+++ dhcpd.h 17 Jun 2007 15:33:24 -0000
@@ -146,6 +146,7 @@
time_t select_interval;
time_t reboot_timeout;
time_t backoff_cutoff;
+ struct string_list *no_link_on;
struct string_list *media;
char *script_name;
enum { IGNORE, ACCEPT, PREFER }
Index: dhctoken.h
================================================== =================
RCS file: /cvs/src/sbin/dhclient/dhctoken.h,v
retrieving revision 1.5
diff -u -r1.5 dhctoken.h
--- dhctoken.h 15 May 2006 08:10:57 -0000 1.5
+++ dhctoken.h 17 Jun 2007 15:33:24 -0000
@@ -79,6 +79,7 @@
#define TOK_REJECT 292
#define TOK_FDDI 293
#define TOK_LINK_TIMEOUT 294
+#define TOK_NO_LINK_ON 295

#define is_identifier(x) ((x) >= TOK_FIRST_TOKEN && \
(x) != TOK_STRING && \

--
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