Add an option to reconfigure dhcpcd without rebinding.

This is primarily for interaction with 3rd party link management, such as PPP.
More work on #159.

4 files changed, 29 insertions, 5 deletions

diff --git a/dhcpcd.8.in b/dhcpcd.8.in
index a1edeebb..0e169d31 100644
--- a/dhcpcd.8.in
+++ b/dhcpcd.8.in
@@ -22,7 +22,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd March 19, 2009
+.Dd March 20, 2009
 .Dt DHCPCD 8 SMM
 .Os
 .Sh NAME
@@ -30,7 +30,7 @@
 .Nd an RFC 2131 compliant DHCP client
 .Sh SYNOPSIS
 .Nm
-.Op Fl bdknpqABDEGKLTV
+.Op Fl bdeknpqABDEGKLTV
 .Op Fl c , -script Ar script
 .Op Fl f , -config Ar file
 .Op Fl h , -hostname Ar hostname
@@ -172,6 +172,13 @@ Echo debug and informational messages to the console.
 Subsequent debug options stop
 .Nm
 from daemonising.
+.It Fl e , -reconfigure
+.Nm
+will re-apply IP address, routing and run
+.Xr dhcpcd-run-hooks 8
+for each interface.
+This is useful so that a 3rd party such as PPP or VPN can change the routing
+table and / or DNS, etc and then instruct dhcpcd to put things back afterwards.
 .It Fl f , -config Ar file
 Specify a config to load instead of
 .Pa @SYSCONFDIR@/dhcpcd.conf .
diff --git a/dhcpcd.c b/dhcpcd.c
index 2c08c8ac..584e31cc 100644
--- a/dhcpcd.c
+++ b/dhcpcd.c
@@ -135,7 +135,7 @@ read_pid(void)
 static void
 usage(void)
 {
-	printf("usage: "PACKAGE" [-dknpqxyADEGHKLOTV] [-c script] [-f file ]"
+	printf("usage: "PACKAGE" [-deknpqxyADEGHKLOTV] [-c script] [-f file ]"
 	    " [-h hostname]\n"
 	    "              [-i classID ] [-l leasetime] [-m metric]"
 	    " [-o option] [-r ipaddr]\n"
@@ -1219,6 +1219,12 @@ handle_signal(_unused void *arg)
 		syslog(LOG_INFO, "received SIGHUP, releasing lease");
 		do_release = 1;
 		break;
+	case SIGUSR1:
+		syslog(LOG_INFO, "received SIGUSR, reconfiguring");
+		for (iface = ifaces; iface; iface = iface->next)
+			if (iface->state->new)
+				configure(iface);
+		break;
 	case SIGPIPE:
 		syslog(LOG_WARNING, "received SIGPIPE");
 		return;
@@ -1277,7 +1283,8 @@ int
 handle_args(struct fd_list *fd, int argc, char **argv)
 {
 	struct interface *ifs, *ifp, *ifl, *ifn, *ift;
-	int do_exit = 0, do_release = 0, do_reboot = 0, opt, oi = 0;
+	int do_exit = 0, do_release = 0, do_reboot = 0, do_reconf = 0;
+	int opt, oi = 0;
 	ssize_t len;
 	size_t l;
 	struct iovec iov[2];
@@ -1354,6 +1361,9 @@ handle_args(struct fd_list *fd, int argc, char **argv)
 	while ((opt = getopt_long(argc, argv, IF_OPTS, cf_options, &oi)) != -1)
 	{
 		switch (opt) {
+		case 'e':
+			do_reconf = 1;
+			break;
 		case 'k':
 			do_release = 1;
 			break;
@@ -1400,6 +1410,8 @@ handle_args(struct fd_list *fd, int argc, char **argv)
 			if (ifn) {
 				if (do_reboot)
 					reconf_reboot(ifn, argc, argv);
+				else if (do_reconf && ifn->state->new)
+					configure(ifn);
 				free_interface(ifp);
 			} else {
 				ifp->next = NULL;
@@ -1445,6 +1457,9 @@ main(int argc, char **argv)
 	while ((opt = getopt_long(argc, argv, IF_OPTS, cf_options, &oi)) != -1)
 	{
 		switch (opt) {
+		case 'e':
+			sig = SIGUSR1;
+			break;
 		case 'f':
 			cffile = optarg;
 			break;
diff --git a/if-options.c b/if-options.c
index 7d048844..15e4bfee 100644
--- a/if-options.c
+++ b/if-options.c
@@ -49,6 +49,7 @@ const struct option cf_options[] = {
 	{"background",      no_argument,       NULL, 'b'},
 	{"script",          required_argument, NULL, 'c'},
 	{"debug",           no_argument,       NULL, 'd'},
+	{"reconfigure",     no_argument,       NULL, 'e'},
 	{"config",          required_argument, NULL, 'f'},
 	{"hostname",        optional_argument, NULL, 'h'},
 	{"vendorclassid",   optional_argument, NULL, 'i'},
@@ -310,6 +311,7 @@ parse_option(struct if_options *ifo, int opt, const char *arg)
 	struct rt *rt;
 
 	switch(opt) {
+	case 'e': /* FALLTHROUGH */
 	case 'n': /* FALLTHROUGH */
 	case 'x': /* FALLTHROUGH */
 	case 'T': /* We need to handle non interface options */
diff --git a/if-options.h b/if-options.h
index 39c390f3..64c8bdea 100644
--- a/if-options.h
+++ b/if-options.h
@@ -37,7 +37,7 @@
 
 /* Don't set any optional arguments here so we retain POSIX
  * compatibility with getopt */
-#define IF_OPTS "bc:df:h:i:kl:m:no:pqr:s:t:u:v:xy:z:ABC:DEF:GI:KLO:Q:TVX:Z:"
+#define IF_OPTS "bc:def:h:i:kl:m:no:pqr:s:t:u:v:xy:z:ABC:DEF:GI:KLN:O:Q:TVX:Z:"
 
 #define DEFAULT_TIMEOUT		30
 #define DEFAULT_REBOOT		10