add some code for keeping track of dns servers and search domains and for writing resolv.conf

6 files changed, 108 insertions, 1 deletions

diff --git a/interface-ip.c b/interface-ip.c
index 2d7a2d0..d2e1461 100644
--- a/interface-ip.c
+++ b/interface-ip.c
@@ -1,6 +1,9 @@
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <unistd.h>
+
+#include <arpa/inet.h>
 
 #include "netifd.h"
 #include "device.h"
@@ -76,6 +79,82 @@ interface_update_proto_route(struct vlist_tree *tree,
 	}
 }
 
+static void
+interface_clear_dns_servers(struct interface *iface)
+{
+	struct dns_server *s, *tmp;
+
+	list_for_each_entry_safe(s, tmp, &iface->proto_dns_servers, list) {
+		list_del(&s->list);
+		free(s);
+	}
+}
+
+static void
+interface_clear_dns_search(struct interface *iface)
+{
+	struct dns_search_domain *s, *tmp;
+
+	list_for_each_entry_safe(s, tmp, &iface->proto_dns_search, list) {
+		list_del(&s->list);
+		free(s);
+	}
+}
+
+void
+interface_clear_dns(struct interface *iface)
+{
+	interface_clear_dns_servers(iface);
+	interface_clear_dns_search(iface);
+}
+
+void
+interface_write_resolv_conf(void)
+{
+	struct interface *iface;
+	struct dns_server *s;
+	struct dns_search_domain *d;
+	char *path = alloca(strlen(resolv_conf) + 5);
+	const char *str;
+	char buf[32];
+	FILE *f;
+
+	sprintf(path, "%s.tmp", resolv_conf);
+	unlink(path);
+	f = fopen(path, "w");
+	if (!f) {
+		D(INTERFACE, "Failed to open %s for writing\n", path);
+		return;
+	}
+
+	vlist_for_each_element(&interfaces, iface, node) {
+		if (iface->state != IFS_UP)
+			continue;
+
+		if (list_empty(&iface->proto_dns_search) &&
+		    list_empty(&iface->proto_dns_servers))
+			continue;
+
+		fprintf(f, "# Interface %s\n", iface->name);
+		list_for_each_entry(s, &iface->proto_dns_servers, list) {
+			str = inet_ntop(s->af, &s->addr, buf, sizeof(buf));
+			if (!str)
+				continue;
+
+			fprintf(f, "nameserver %s\n", str);
+		}
+
+		list_for_each_entry(d, &iface->proto_dns_search, list) {
+			fprintf(f, "search %s\n", d->name);
+		}
+	}
+	fclose(f);
+	if (rename(path, resolv_conf) < 0) {
+		D(INTERFACE, "Failed to replace %s\n", resolv_conf);
+		unlink(path);
+	}
+}
+
 void
 interface_ip_init(struct interface *iface)
 {
diff --git a/interface-ip.h b/interface-ip.h
index 057f0d0..23782ad 100644
--- a/interface-ip.h
+++ b/interface-ip.h
@@ -43,6 +43,19 @@ struct device_route {
 	union if_addr addr;
 };
 
+struct dns_server {
+	struct list_head list;
+	int af;
+	union if_addr addr;
+};
+
+struct dns_search_domain {
+	struct list_head list;
+	char name[];
+};
+
 void interface_ip_init(struct interface *iface);
+void interface_clear_dns(struct interface *iface);
+void interface_write_resolv_conf(void);
 
 #endif
diff --git a/interface.c b/interface.c
index 17cb754..37b20cc 100644
--- a/interface.c
+++ b/interface.c
@@ -185,6 +185,7 @@ interface_claim_device(struct interface *iface)
 static void
 interface_cleanup(struct interface *iface)
 {
+	interface_clear_dns(iface);
 	interface_clear_errors(iface);
 	if (iface->main_dev.dev)
 		device_remove_user(&iface->main_dev);
@@ -241,6 +242,7 @@ interface_proto_cb(struct interface_proto_state *state, enum interface_proto_eve
 		iface->state = IFS_UP;
 		iface->start_time = system_get_rtime();
 		interface_event(iface, IFEV_UP);
+		interface_write_resolv_conf();
 		break;
 	case IFPEV_DOWN:
 		if (iface->state == IFS_DOWN)
@@ -285,6 +287,8 @@ interface_init(struct interface *iface, const char *name,
 	strncpy(iface->name, name, sizeof(iface->name) - 1);
 	INIT_LIST_HEAD(&iface->errors);
 	INIT_LIST_HEAD(&iface->hotplug_list);
+	INIT_LIST_HEAD(&iface->proto_dns_search);
+	INIT_LIST_HEAD(&iface->proto_dns_servers);
 
 	iface->main_dev.cb = interface_cb;
 	iface->l3_dev = &iface->main_dev;
diff --git a/interface.h b/interface.h
index 0e81304..6620796 100644
--- a/interface.h
+++ b/interface.h
@@ -67,6 +67,9 @@ struct interface {
 	struct vlist_tree proto_addr;
 	struct vlist_tree proto_route;
 
+	struct list_head proto_dns_servers;
+	struct list_head proto_dns_search;
+
 	/* errors/warnings while trying to bring up the interface */
 	struct list_head errors;
 
diff --git a/main.c b/main.c
index 02dd1e5..5770782 100644
--- a/main.c
+++ b/main.c
@@ -12,6 +12,7 @@
 
 unsigned int debug_mask = 0;
 const char *main_path = DEFAULT_MAIN_PATH;
+const char *resolv_conf = DEFAULT_RESOLV_CONF;
 static char **global_argv;
 
 static void netifd_do_restart(struct uloop_timeout *timeout)
@@ -47,6 +48,7 @@ static int usage(const char *progname)
 		" -s <path>:		Path to the ubus socket\n"
 		" -p <path>:		Path to netifd addons (default: %s)\n"
 		" -h <path>:		Path to the hotplug script\n"
+		" -r <path>:		Path to resolv.conf\n"
 		"			(default: "DEFAULT_HOTPLUG_PATH")\n"
 		"\n", progname, main_path);
 
@@ -60,7 +62,7 @@ int main(int argc, char **argv)
 
 	global_argv = argv;
 
-	while ((ch = getopt(argc, argv, "d:s:")) != -1) {
+	while ((ch = getopt(argc, argv, "d:s:p:h:r:")) != -1) {
 		switch(ch) {
 		case 'd':
 			debug_mask = strtoul(optarg, NULL, 0);
@@ -74,6 +76,9 @@ int main(int argc, char **argv)
 		case 'h':
 			hotplug_cmd_path = optarg;
 			break;
+		case 'r':
+			resolv_conf = optarg;
+			break;
 		default:
 			return usage(argv[0]);
 		}
diff --git a/netifd.h b/netifd.h
index aa04c51..d034e7a 100644
--- a/netifd.h
+++ b/netifd.h
@@ -16,11 +16,14 @@
 #ifdef DUMMY_MODE
 #define DEFAULT_MAIN_PATH	"./dummy"
 #define DEFAULT_HOTPLUG_PATH	"./scripts/hotplug-cmd"
+#define DEFAULT_RESOLV_CONF	"./tmp/resolv.conf"
 #else
 #define DEFAULT_MAIN_PATH	"/lib/netifd"
 #define DEFAULT_HOTPLUG_PATH	"/sbin/hotplug-cmd"
+#define DEFAULT_RESOLV_CONF	"/tmp/resolv.conf.auto"
 #endif
 
+extern const char *resolv_conf;
 extern char *hotplug_cmd_path;
 extern unsigned int debug_mask;