From: Oren Laadan on
From: Dan Smith <danms(a)us.ibm.com>

This is the kernel equivalent of "ip link del $name" and matches the
existing rtnl_newlink() equivalent of "ip link add $name". It factors
out the message creation and dispatch code a little further into
rtnl_do() before adding the new function.

Cc: netdev(a)vger.kernel.org
Signed-off-by: Dan Smith <danms(a)us.ibm.com>
---
net/checkpoint_dev.c | 86 +++++++++++++++++++++++++++++++++++++++++--------
1 files changed, 72 insertions(+), 14 deletions(-)

diff --git a/net/checkpoint_dev.c b/net/checkpoint_dev.c
index 34a6bdb..5097011 100644
--- a/net/checkpoint_dev.c
+++ b/net/checkpoint_dev.c
@@ -475,22 +475,49 @@ static struct sk_buff *new_link_msg(new_link_fn fn, void *data, char *name)
return skb;
}

-static struct net_device *rtnl_newlink(new_link_fn fn, void *data, char *name)
+static struct sk_buff *del_link_msg(char *name)
+{
+ int ret = -ENOMEM;
+ int flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_ACK;
+ struct nlmsghdr *nlh;
+ struct sk_buff *skb;
+ struct ifinfomsg *ifm;
+
+ skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+ if (!skb)
+ return ERR_PTR(-ENOMEM);
+
+ nlh = nlmsg_put(skb, 0, 0, RTM_DELLINK, sizeof(*ifm), flags);
+ if (!nlh)
+ goto out;
+
+ ifm = nlmsg_data(nlh);
+ memset(ifm, 0, sizeof(*ifm));
+
+ ret = nla_put_string(skb, IFLA_IFNAME, name);
+ if (ret)
+ goto out;
+
+ nlmsg_end(skb, nlh);
+
+ out:
+ if (ret < 0) {
+ kfree_skb(skb);
+ skb = ERR_PTR(ret);
+ }
+
+ return skb;
+}
+
+static int rtnl_do(struct sk_buff *skb)
{
int ret = -ENOMEM;
struct socket *rtnl = NULL;
- struct sk_buff *skb = NULL;
+ struct sk_buff *rskb = NULL;
struct nlmsghdr *nlh;
struct msghdr msg;
struct kvec kvec;

- skb = new_link_msg(fn, data, name);
- if (IS_ERR(skb)) {
- ckpt_debug("failed to create new link message: %li\n",
- PTR_ERR(skb));
- return ERR_PTR(PTR_ERR(skb));
- }
-
memset(&msg, 0, sizeof(msg));
kvec.iov_len = skb->len;
kvec.iov_base = skb->head;
@@ -510,25 +537,56 @@ static struct net_device *rtnl_newlink(new_link_fn fn, void *data, char *name)
goto out;
}

- /* Free the send skb to make room for the receive skb */
- kfree_skb(skb);
-
- nlh = rtnl_get_response(rtnl, &skb);
+ nlh = rtnl_get_response(rtnl, &rskb);
if (IS_ERR(nlh)) {
ret = PTR_ERR(nlh);
ckpt_debug("RTNETLINK said: %i\n", ret);
}
out:
rtnl_close(rtnl);
+ kfree_skb(rskb);
out_noclose:
- kfree_skb(skb);
+ return ret;
+}

+static struct net_device *rtnl_newlink(new_link_fn fn, void *data, char *name)
+{
+ struct sk_buff *skb;
+ int ret;
+
+ skb = new_link_msg(fn, data, name);
+ if (IS_ERR(skb)) {
+ ckpt_debug("failed to create new link message: %li\n",
+ PTR_ERR(skb));
+ return ERR_PTR(PTR_ERR(skb));
+ }
+
+ ret = rtnl_do(skb);
+ kfree_skb(skb);
if (ret < 0)
return ERR_PTR(ret);
else
return dev_get_by_name(current->nsproxy->net_ns, name);
}

+static int rtnl_dellink(char *name)
+{
+ struct sk_buff *skb;
+ int ret;
+
+ skb = del_link_msg(name);
+ if (IS_ERR(skb)) {
+ ckpt_debug("failed to create del link message: %li\n",
+ PTR_ERR(skb));
+ return PTR_ERR(skb);
+ }
+
+ ret = rtnl_do(skb);
+ kfree_skb(skb);
+
+ return ret;
+}
+
static int netdev_noop(void *data)
{
return 0;
--
1.6.3.3

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