add veth link support

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Thomas Graf <tgraf@suug.ch>

2 files changed, 282 insertions, 1 deletions

diff --git a/lib/route/link.c b/lib/route/link.c
index 37938aa..b758013 100644
--- a/lib/route/link.c
+++ b/lib/route/link.c
@@ -260,7 +260,7 @@ static int link_clone(struct nl_object *_dst, struct nl_object *_src)
 	return 0;
 }
 
-static struct nla_policy link_policy[IFLA_MAX+1] = {
+struct nla_policy link_policy[IFLA_MAX+1] = {
 	[IFLA_IFNAME]		= { .type = NLA_STRING,
 				    .maxlen = IFNAMSIZ },
 	[IFLA_MTU]		= { .type = NLA_U32 },
diff --git a/lib/route/link/veth.c b/lib/route/link/veth.c
new file mode 100644
index 0000000..dba1294
--- /dev/null
+++ b/lib/route/link/veth.c
@@ -0,0 +1,281 @@
+/*
+ * lib/route/link/veth.c	Virtual Ethernet
+ *
+ *	This library is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU Lesser General Public
+ *	License as published by the Free Software Foundation version 2.1
+ *	of the License.
+ *
+ * Copyright (c) 2013 Cong Wang <xiyou.wangcong@gmail.com>
+ */
+
+/**
+ * @ingroup link
+ * @defgroup veth VETH
+ * Virtual Ethernet
+ *
+ * @details
+ * \b Link Type Name: "veth"
+ *
+ * @route_doc{link_veth, VETH Documentation}
+ *
+ * @{
+ */
+
+#include <netlink-private/netlink.h>
+#include <netlink/netlink.h>
+#include <netlink/attr.h>
+#include <netlink/utils.h>
+#include <netlink/object.h>
+#include <netlink/route/rtnl.h>
+#include <netlink-private/route/link/api.h>
+#include <netlink/route/link/veth.h>
+
+#include <linux/if_link.h>
+
+static struct nla_policy veth_policy[VETH_INFO_MAX+1] = {
+	[VETH_INFO_PEER]	= { .minlen = sizeof(struct ifinfomsg) },
+};
+
+static int veth_parse(struct rtnl_link *link, struct nlattr *data,
+		      struct nlattr *xstats)
+{
+	struct nlattr *tb[VETH_INFO_MAX+1];
+	struct nlattr *peer_tb[IFLA_MAX + 1];
+	struct rtnl_link *peer = link->l_info;
+	int err;
+
+	NL_DBG(3, "Parsing veth link info");
+
+	if ((err = nla_parse_nested(tb, VETH_INFO_MAX, data, veth_policy)) < 0)
+		goto errout;
+
+	if (tb[VETH_INFO_PEER]) {
+		struct nlattr *nla_peer;
+		struct ifinfomsg *ifi;
+
+		nla_peer = tb[VETH_INFO_PEER];
+		ifi = nla_data(nla_peer);
+
+		peer->l_family = ifi->ifi_family;
+		peer->l_arptype = ifi->ifi_type;
+		peer->l_index = ifi->ifi_index;
+		peer->l_flags = ifi->ifi_flags;
+		peer->l_change = ifi->ifi_change;
+		err = nla_parse(peer_tb, IFLA_MAX,
+				nla_data(nla_peer) + sizeof(struct ifinfomsg),
+				nla_len(nla_peer) - sizeof(struct ifinfomsg),
+				link_policy);
+		if (err < 0)
+			goto errout;
+
+		err = rtnl_link_info_parse(peer, peer_tb);
+		if (err < 0)
+			goto errout;
+	}
+
+	err = 0;
+
+errout:
+	return err;
+}
+
+static void veth_dump_line(struct rtnl_link *link, struct nl_dump_params *p)
+{
+}
+
+static void veth_dump_details(struct rtnl_link *link, struct nl_dump_params *p)
+{
+	struct rtnl_link *peer = link->l_info;
+	char *name;
+	name = rtnl_link_get_name(peer);
+	nl_dump(p, "      peer ");
+	if (name)
+		nl_dump_line(p, "%s\n", name);
+	else
+		nl_dump_line(p, "%u\n", peer->l_index);
+}
+
+static int veth_clone(struct rtnl_link *dst, struct rtnl_link *src)
+{
+	struct rtnl_link *dst_peer , *src_peer = src->l_info;
+	int err;
+
+	dst_peer = dst->l_info = rtnl_link_alloc();
+	if (!dst_peer || !src_peer)
+		return -NLE_NOMEM;
+	if ((err = rtnl_link_set_type(dst, "veth")) < 0) {
+		rtnl_link_put(dst_peer);
+		return err;
+	}
+
+	memcpy(dst_peer, src_peer, sizeof(struct rtnl_link));
+
+	return 0;
+}
+
+static int veth_put_attrs(struct nl_msg *msg, struct rtnl_link *link)
+{
+	struct rtnl_link *peer = link->l_info;
+	struct ifinfomsg ifi;
+	struct nlattr *data, *info_peer;
+
+	memset(&ifi, 0, sizeof ifi);
+	ifi.ifi_family = peer->l_family;
+	ifi.ifi_type = peer->l_arptype;
+	ifi.ifi_index = peer->l_index;
+	ifi.ifi_flags = peer->l_flags;
+	ifi.ifi_change = peer->l_change;
+
+	if (!(data = nla_nest_start(msg, IFLA_INFO_DATA)))
+		return -NLE_MSGSIZE;
+	if (!(info_peer = nla_nest_start(msg, VETH_INFO_PEER)))
+		return -NLE_MSGSIZE;
+	if (nlmsg_append(msg, &ifi, sizeof(ifi), NLMSG_ALIGNTO) < 0)
+		return -NLE_MSGSIZE;
+	rtnl_link_fill_info(msg, peer);
+	nla_nest_end(msg, info_peer);
+	nla_nest_end(msg, data);
+
+	return 0;
+}
+
+static struct rtnl_link_info_ops veth_info_ops = {
+	.io_name		= "veth",
+	.io_parse		= veth_parse,
+	.io_dump = {
+	    [NL_DUMP_LINE]	= veth_dump_line,
+	    [NL_DUMP_DETAILS]	= veth_dump_details,
+	},
+	.io_clone		= veth_clone,
+	.io_put_attrs		= veth_put_attrs,
+};
+
+/** @cond SKIP */
+
+#define IS_VETH_LINK_ASSERT(link) \
+	if ((link)->l_info_ops != &veth_info_ops) { \
+		APPBUG("Link is not a veth link. set type \"veth\" first."); \
+		return NULL; \
+	}
+/** @endcond */
+
+/**
+ * @name VETH Object
+ * @{
+ */
+
+/**
+ * Allocate link object of type veth
+ *
+ * @return Allocated link object or NULL.
+ */
+struct rtnl_link *rtnl_link_veth_alloc(void)
+{
+	struct rtnl_link *link, *peer;
+	int err;
+
+	if (!(link = rtnl_link_alloc()))
+		return NULL;
+	if (!(peer = rtnl_link_alloc())) {
+		rtnl_link_put(link);
+		return NULL;
+	}
+
+	if ((err = rtnl_link_set_type(link, "veth")) < 0) {
+		rtnl_link_put(peer);
+		rtnl_link_put(link);
+		return NULL;
+	}
+	if ((err = rtnl_link_set_type(peer, "veth")) < 0) {
+		rtnl_link_put(peer);
+		rtnl_link_put(link);
+		return NULL;
+	}
+
+	link->l_info = peer;
+	peer->l_info = link;
+	return link;
+}
+
+/**
+ * Get the peer link of a veth link
+ *
+ * @return the peer link object.
+ */
+struct rtnl_link *rtnl_link_veth_get_peer(struct rtnl_link *link)
+{
+	IS_VETH_LINK_ASSERT(link);
+	return link->l_info;
+}
+
+/**
+ * Release a veth link and its peer
+ *
+ */
+void rtnl_link_veth_release(struct rtnl_link *link)
+{
+	struct rtnl_link *peer = rtnl_link_veth_get_peer(link);
+	rtnl_link_put(peer);
+	rtnl_link_put(link);
+}
+
+/**
+ * Check if link is a veth link
+ * @arg link		Link object
+ *
+ * @return True if link is a veth link, otherwise false is returned.
+ */
+int rtnl_link_is_veth(struct rtnl_link *link)
+{
+	return link->l_info_ops && !strcmp(link->l_info_ops->io_name, "veth");
+}
+
+/**
+ * Create a new kernel veth device
+ * @arg sock		netlink socket
+ * @arg name		name of the veth device or NULL
+ * @arg peer_name	name of its peer or NULL
+ *
+ * Creates a new veth device pair in the kernel. If no name is
+ * provided, the kernel will automatically pick a name of the
+ * form "veth%d" (e.g. veth0, veth1, etc.)
+ *
+ * @return 0 on success or a negative error code
+ */
+int rtnl_link_veth_add(struct nl_sock *sock, const char *name,
+                       const char *peer_name)
+{
+	struct rtnl_link *link, *peer;
+	int err = -NLE_NOMEM;
+
+	if (!(link = rtnl_link_veth_alloc()))
+		return -NLE_NOMEM;
+	peer = rtnl_link_veth_get_peer(link);
+
+	if (name && peer_name) {
+		rtnl_link_set_name(link, name);
+		rtnl_link_set_name(peer, peer_name);
+	}
+
+	err = rtnl_link_add(sock, link, NLM_F_CREATE);
+
+	rtnl_link_put(peer);
+	rtnl_link_put(link);
+
+        return err;
+}
+
+/** @} */
+
+static void __init veth_init(void)
+{
+	rtnl_link_register_info(&veth_info_ops);
+}
+
+static void __exit veth_exit(void)
+{
+	rtnl_link_unregister_info(&veth_info_ops);
+}
+
+/** @} */