Add functions for adding and flushing nameservers with resolver

2 files changed, 115 insertions, 0 deletions

diff --git a/gresolv/gresolv.c b/gresolv/gresolv.c
index 26056767..d1aa8d27 100644
--- a/gresolv/gresolv.c
+++ b/gresolv/gresolv.c
@@ -23,17 +23,88 @@
 #include <config.h>
 #endif
 
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <resolv.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <arpa/nameser.h>
+
 #include "gresolv.h"
 
+struct resolv_nameserver {
+	char *address;
+	uint16_t port;
+	unsigned long flags;
+
+	GIOChannel *udp_channel;
+};
+
 struct _GResolv {
 	gint ref_count;
 
 	int index;
+	GList *nameserver_list;
 
 	GResolvDebugFunc debug_func;
 	gpointer debug_data;
 };
 
+static void free_nameserver(struct resolv_nameserver *nameserver)
+{
+	if (nameserver == NULL)
+		return;
+
+	if (nameserver->udp_channel != NULL)
+		g_io_channel_unref(nameserver->udp_channel);
+
+	g_free(nameserver->address);
+	g_free(nameserver);
+}
+
+static void flush_nameservers(GResolv *resolv)
+{
+	GList *list;
+
+	for (list = g_list_first(resolv->nameserver_list);
+					list; list = g_list_next(list))
+		free_nameserver(list->data);
+
+	g_list_free(resolv->nameserver_list);
+	resolv->nameserver_list = NULL;
+}
+
+static int connect_udp_channel(struct resolv_nameserver *nameserver)
+{
+	struct sockaddr_in sin;
+	int sk;
+
+	sk = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+	if (sk < 0)
+		return -EIO;
+
+	memset(&sin, 0, sizeof(sin));
+	sin.sin_family = AF_INET;
+	sin.sin_port = htons(nameserver->port);
+	sin.sin_addr.s_addr = inet_addr(nameserver->address);
+
+	if (connect(sk, (struct sockaddr *) &sin, sizeof(sin)) < 0) {
+		close(sk);
+		return -EIO;
+	}
+
+	nameserver->udp_channel = g_io_channel_unix_new(sk);
+	if (nameserver->udp_channel == NULL) {
+		close(sk);
+		return -ENOMEM;
+	}
+
+	g_io_channel_set_close_on_unref(nameserver->udp_channel, TRUE);
+
+	return 0;
+}
+
 GResolv *g_resolv_new(int index)
 {
 	GResolv *resolv;
@@ -48,6 +119,7 @@ GResolv *g_resolv_new(int index)
 	resolv->ref_count = 1;
 
 	resolv->index = index;
+	resolv->nameserver_list = NULL;
 
 	return resolv;
 }
@@ -70,6 +142,8 @@ void g_resolv_unref(GResolv *resolv)
 	if (g_atomic_int_dec_and_test(&resolv->ref_count) == FALSE)
 		return;
 
+	flush_nameservers(resolv);
+
 	g_free(resolv);
 }
 
@@ -82,3 +156,38 @@ void g_resolv_set_debug(GResolv *resolv,
 	resolv->debug_func = func;
 	resolv->debug_data = data;
 }
+
+int g_resolv_add_nameserver(GResolv *resolv, const char *address,
+					uint16_t port, unsigned long flags)
+{
+	struct resolv_nameserver *nameserver;
+
+	if (resolv == NULL)
+		return -EINVAL;
+
+	nameserver = g_try_new0(struct resolv_nameserver, 1);
+	if (nameserver == NULL)
+		return -ENOMEM;
+
+	nameserver->address = g_strdup(address);
+	nameserver->port = port;
+	nameserver->flags = flags;
+
+	if (connect_udp_channel(nameserver) < 0) {
+		free_nameserver(nameserver);
+		return -EIO;
+	}
+
+	resolv->nameserver_list = g_list_append(resolv->nameserver_list,
+								nameserver);
+
+	return 0;
+}
+
+void g_resolv_flush_nameservers(GResolv *resolv)
+{
+	if (resolv == NULL)
+		return;
+
+	flush_nameservers(resolv);
+}
diff --git a/gresolv/gresolv.h b/gresolv/gresolv.h
index 521abd30..40b49728 100644
--- a/gresolv/gresolv.h
+++ b/gresolv/gresolv.h
@@ -22,6 +22,8 @@
 #ifndef __G_RESOLV_H
 #define __G_RESOLV_H
 
+#include <stdint.h>
+
 #include <glib.h>
 
 #ifdef __cplusplus
@@ -42,6 +44,10 @@ void g_resolv_unref(GResolv *resolv);
 void g_resolv_set_debug(GResolv *resolv,
 				GResolvDebugFunc func, gpointer data);
 
+int g_resolv_add_nameserver(GResolv *resolv, const char *address,
+					uint16_t port, unsigned long flags);
+void g_resolv_flush_nameservers(GResolv *resolv);
+
 #ifdef __cplusplus
 }
 #endif