device: add veth support

The veth config code mostly handles the primary interface of a veth pair,
the secondary interface is not explicitly referenced and will be found as
an unrelated interface after the pair has been created.

This doesn't only allow us to keep the veth code simple (and similar to
existing device handlers), but will also avoid complicating handling
unnecessarily in case the secondary interface is moved into another network
namespace.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

1 files changed, 247 insertions, 0 deletions

diff --git a/veth.c b/veth.c
new file mode 100644
index 0000000..e109f27
--- /dev/null
+++ b/veth.c
@@ -0,0 +1,247 @@
+/*
+ * netifd - network interface daemon
+ * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
+ * Copyright (C) 2013 Jo-Philipp Wich <jow@openwrt.org>
+ * Copyright (C) 2017 Matthias Schiffer <mschiffer@universe-factory.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+#include <errno.h>
+#include <net/ethernet.h>
+
+#ifdef linux
+#include <netinet/ether.h>
+#endif
+
+#include "netifd.h"
+#include "device.h"
+#include "interface.h"
+#include "system.h"
+
+enum {
+	VETH_ATTR_MACADDR,
+	VETH_ATTR_PEER_NAME,
+	VETH_ATTR_PEER_MACADDR,
+	__VETH_ATTR_MAX
+};
+
+static const struct blobmsg_policy veth_attrs[__VETH_ATTR_MAX] = {
+	[VETH_ATTR_MACADDR] = { "macaddr", BLOBMSG_TYPE_STRING },
+	[VETH_ATTR_PEER_NAME]  = { "peer_name", BLOBMSG_TYPE_STRING },
+	[VETH_ATTR_PEER_MACADDR] = { "peer_macaddr", BLOBMSG_TYPE_STRING },
+};
+
+static const struct uci_blob_param_list veth_attr_list = {
+	.n_params = __VETH_ATTR_MAX,
+	.params = veth_attrs,
+
+	.n_next = 1,
+	.next = { &device_attr_list },
+};
+
+struct veth {
+	struct device dev;
+
+	device_state_cb set_state;
+
+	struct blob_attr *config_data;
+	struct veth_config config;
+};
+
+static int
+veth_set_down(struct veth *veth)
+{
+	veth->set_state(&veth->dev, false);
+	system_veth_del(&veth->dev);
+
+	return 0;
+}
+
+static int
+veth_set_up(struct veth *veth)
+{
+	int ret;
+
+	ret = system_veth_add(&veth->dev, &veth->config);
+	if (ret < 0)
+		return ret;
+
+	ret = veth->set_state(&veth->dev, true);
+	if (ret)
+		goto delete;
+
+	return 0;
+
+delete:
+	system_veth_del(&veth->dev);
+	return ret;
+}
+
+static int
+veth_set_state(struct device *dev, bool up)
+{
+	struct veth *veth;
+
+	D(SYSTEM, "veth_set_state(%s, %u)\n", dev->ifname, up);
+
+	veth = container_of(dev, struct veth, dev);
+	if (up)
+		return veth_set_up(veth);
+	else
+		return veth_set_down(veth);
+}
+
+static void
+veth_free(struct device *dev)
+{
+	struct veth *veth;
+
+	veth = container_of(dev, struct veth, dev);
+	free(veth->config_data);
+	free(veth);
+}
+
+static void
+veth_dump_info(struct device *dev, struct blob_buf *b)
+{
+	struct veth *veth;
+
+	veth = container_of(dev, struct veth, dev);
+	if (veth->config.flags & VETH_OPT_PEER_NAME)
+		blobmsg_add_string(b, "peer", veth->config.peer_name);
+	system_if_dump_info(dev, b);
+}
+
+static void
+veth_config_init(struct device *dev)
+{
+	device_set_present(dev, true);
+}
+
+static void
+veth_apply_settings(struct veth *veth, struct blob_attr **tb)
+{
+	struct veth_config *cfg = &veth->config;
+	struct blob_attr *cur;
+	struct ether_addr *ea;
+
+	cfg->flags = 0;
+
+	if ((cur = tb[VETH_ATTR_MACADDR]))
+	{
+		ea = ether_aton(blobmsg_data(cur));
+		if (ea) {
+			memcpy(cfg->macaddr, ea, 6);
+			cfg->flags |= VETH_OPT_MACADDR;
+		}
+	}
+
+	if ((cur = tb[VETH_ATTR_PEER_NAME]))
+	{
+		strncpy(cfg->peer_name, blobmsg_get_string(cur), sizeof(cfg->peer_name)-1);
+		cfg->flags |= VETH_OPT_PEER_NAME;
+	}
+
+	if ((cur = tb[VETH_ATTR_PEER_MACADDR]))
+	{
+		ea = ether_aton(blobmsg_data(cur));
+		if (ea) {
+			memcpy(cfg->peer_macaddr, ea, 6);
+			cfg->flags |= VETH_OPT_PEER_MACADDR;
+		}
+	}
+}
+
+static enum dev_change_type
+veth_reload(struct device *dev, struct blob_attr *attr)
+{
+	struct blob_attr *tb_dev[__DEV_ATTR_MAX];
+	struct blob_attr *tb_mv[__VETH_ATTR_MAX];
+	enum dev_change_type ret = DEV_CONFIG_APPLIED;
+	struct veth *veth;
+
+	veth = container_of(dev, struct veth, dev);
+	attr = blob_memdup(attr);
+
+	blobmsg_parse(device_attr_list.params, __DEV_ATTR_MAX, tb_dev,
+		blob_data(attr), blob_len(attr));
+	blobmsg_parse(veth_attrs, __VETH_ATTR_MAX, tb_mv,
+		blob_data(attr), blob_len(attr));
+
+	device_init_settings(dev, tb_dev);
+	veth_apply_settings(veth, tb_mv);
+
+	if (veth->config_data) {
+		struct blob_attr *otb_dev[__DEV_ATTR_MAX];
+		struct blob_attr *otb_mv[__VETH_ATTR_MAX];
+
+		blobmsg_parse(device_attr_list.params, __DEV_ATTR_MAX, otb_dev,
+			blob_data(veth->config_data), blob_len(veth->config_data));
+
+		if (uci_blob_diff(tb_dev, otb_dev, &device_attr_list, NULL))
+		    ret = DEV_CONFIG_RESTART;
+
+		blobmsg_parse(veth_attrs, __VETH_ATTR_MAX, otb_mv,
+			blob_data(veth->config_data), blob_len(veth->config_data));
+
+		if (uci_blob_diff(tb_mv, otb_mv, &veth_attr_list, NULL))
+		    ret = DEV_CONFIG_RESTART;
+
+		veth_config_init(dev);
+	}
+
+	free(veth->config_data);
+	veth->config_data = attr;
+	return ret;
+}
+
+static struct device *
+veth_create(const char *name, struct device_type *devtype,
+	struct blob_attr *attr)
+{
+	struct veth *veth;
+	struct device *dev = NULL;
+
+	veth = calloc(1, sizeof(*veth));
+	if (!veth)
+		return NULL;
+
+	dev = &veth->dev;
+	device_init(dev, devtype, name);
+	dev->config_pending = true;
+
+	veth->set_state = dev->set_state;
+	dev->set_state = veth_set_state;
+
+	dev->hotplug_ops = NULL;
+
+	veth_reload(dev, attr);
+
+	return dev;
+}
+
+static struct device_type veth_device_type = {
+	.name = "veth",
+	.config_params = &veth_attr_list,
+	.create = veth_create,
+	.config_init = veth_config_init,
+	.reload = veth_reload,
+	.free = veth_free,
+	.dump_info = veth_dump_info,
+};
+
+static void __init veth_device_type_init(void)
+{
+	device_type_add(&veth_device_type);
+}