[B.A.T.M.A.N.] [RFC v4 01/19] batman-adv: Move common genl doit code pre/post hooks

Sven Eckelmann
2019-01-19T15:56:08Z

The commit ff4c92d85c6f ("genetlink: introduce pre_doit/post_doit hooks")
intoduced a mechanism to run specific code for doit hooks before/after the
hooks are run. Since all doit hooks are requiring the batadv softif, it
should be retrieved/freed in these helpers to simplify the code.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
net/batman-adv/netlink.c | 143 +++++++++++++++++++++++++++------------
1 file changed, 100 insertions(+), 43 deletions(-)

diff --git a/net/batman-adv/netlink.c b/net/batman-adv/netlink.c
index 5fe833cc..e56c40d1 100644
--- a/net/batman-adv/netlink.c
+++ b/net/batman-adv/netlink.c
@@ -20,8 +20,10 @@
#include "main.h"

#include <linux/atomic.h>
+#include <linux/bitops.h>
#include <linux/byteorder/generic.h>
#include <linux/cache.h>
+#include <linux/err.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/genetlink.h>
@@ -54,6 +56,8 @@
#include "tp_meter.h"
#include "translation-table.h"

+struct net;
+
struct genl_family batadv_netlink_family;

/* multicast groups */
@@ -61,6 +65,18 @@ enum batadv_netlink_multicast_groups {
BATADV_NL_MCGRP_TPMETER,
};

+/**
+ * enum batadv_genl_ops_flags - flags for genl_ops's internal_flags
+ */
+enum batadv_genl_ops_flags {
+ /**
+ * @BATADV_FLAG_NEED_MESH: request requires valid soft interface in
+ * attribute BATADV_ATTR_MESH_IFINDEX and expects a pointer to it to be
+ * saved in info->user_ptr[0]
+ */
+ BATADV_FLAG_NEED_MESH = BIT(0),
+};
+
static const struct genl_multicast_group batadv_netlink_mcgrps[] = {
[BATADV_NL_MCGRP_TPMETER] = { .name = BATADV_NL_MCAST_GROUP_TPMETER },
};
@@ -329,40 +345,24 @@ int batadv_netlink_tpmeter_notify(struct batadv_priv *bat_priv, const u8 *dst,
static int
batadv_netlink_tp_meter_start(struct sk_buff *skb, struct genl_info *info)
{
- struct net *net = genl_info_net(info);
- struct net_device *soft_iface;
- struct batadv_priv *bat_priv;
+ struct batadv_priv *bat_priv = info->user_ptr[0];
struct sk_buff *msg = NULL;
u32 test_length;
void *msg_head;
- int ifindex;
u32 cookie;
u8 *dst;
int ret;

- if (!info->attrs[BATADV_ATTR_MESH_IFINDEX])
- return -EINVAL;
-
if (!info->attrs[BATADV_ATTR_ORIG_ADDRESS])
return -EINVAL;

if (!info->attrs[BATADV_ATTR_TPMETER_TEST_TIME])
return -EINVAL;

- ifindex = nla_get_u32(info->attrs[BATADV_ATTR_MESH_IFINDEX]);
- if (!ifindex)
- return -EINVAL;
-
dst = nla_data(info->attrs[BATADV_ATTR_ORIG_ADDRESS]);

test_length = nla_get_u32(info->attrs[BATADV_ATTR_TPMETER_TEST_TIME]);

- soft_iface = dev_get_by_index(net, ifindex);
- if (!soft_iface || !batadv_softif_is_valid(soft_iface)) {
- ret = -ENODEV;
- goto out;
- }
-
msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (!msg) {
ret = -ENOMEM;
@@ -377,15 +377,11 @@ batadv_netlink_tp_meter_start(struct sk_buff *skb, struct genl_info *info)
goto out;
}

- bat_priv = netdev_priv(soft_iface);
batadv_tp_start(bat_priv, dst, test_length, &cookie);

ret = batadv_netlink_tp_meter_put(msg, cookie);

out:
- if (soft_iface)
- dev_put(soft_iface);
-
if (ret) {
if (msg)
nlmsg_free(msg);
@@ -406,38 +402,17 @@ batadv_netlink_tp_meter_start(struct sk_buff *skb, struct genl_info *info)
static int
batadv_netlink_tp_meter_cancel(struct sk_buff *skb, struct genl_info *info)
{
- struct net *net = genl_info_net(info);
- struct net_device *soft_iface;
- struct batadv_priv *bat_priv;
- int ifindex;
+ struct batadv_priv *bat_priv = info->user_ptr[0];
u8 *dst;
int ret = 0;

- if (!info->attrs[BATADV_ATTR_MESH_IFINDEX])
- return -EINVAL;
-
if (!info->attrs[BATADV_ATTR_ORIG_ADDRESS])
return -EINVAL;

- ifindex = nla_get_u32(info->attrs[BATADV_ATTR_MESH_IFINDEX]);
- if (!ifindex)
- return -EINVAL;
-
dst = nla_data(info->attrs[BATADV_ATTR_ORIG_ADDRESS]);

- soft_iface = dev_get_by_index(net, ifindex);
- if (!soft_iface || !batadv_softif_is_valid(soft_iface)) {
- ret = -ENODEV;
- goto out;
- }
-
- bat_priv = netdev_priv(soft_iface);
batadv_tp_stop(bat_priv, dst, BATADV_TP_REASON_CANCEL);

-out:
- if (soft_iface)
- dev_put(soft_iface);
-
return ret;
}

@@ -545,6 +520,84 @@ batadv_netlink_dump_hardifs(struct sk_buff *msg, struct netlink_callback *cb)
return msg->len;
}

+/**
+ * batadv_get_softif_from_info() - Retrieve soft interface from genl attributes
+ * @net: the applicable net namespace
+ * @info: receiver information
+ *
+ * Return: Pointer to soft interface (with increased refcnt) on success, error
+ * pointer on error
+ */
+static struct net_device *
+batadv_get_softif_from_info(struct net *net, struct genl_info *info)
+{
+ struct net_device *soft_iface;
+ int ifindex;
+
+ if (!info->attrs[BATADV_ATTR_MESH_IFINDEX])
+ return ERR_PTR(-EINVAL);
+
+ ifindex = nla_get_u32(info->attrs[BATADV_ATTR_MESH_IFINDEX]);
+
+ soft_iface = dev_get_by_index(net, ifindex);
+ if (!soft_iface)
+ return ERR_PTR(-ENODEV);
+
+ if (!batadv_softif_is_valid(soft_iface))
+ goto err_put_softif;
+
+ return soft_iface;
+
+err_put_softif:
+ dev_put(soft_iface);
+
+ return ERR_PTR(-EINVAL);
+}
+
+/**
+ * batadv_pre_doit() - Prepare batman-adv genl doit request
+ * @ops: requested netlink operation
+ * @skb: Netlink message with request data
+ * @info: receiver information
+ *
+ * Return: 0 on success or negative error number in case of failure
+ */
+static int batadv_pre_doit(const struct genl_ops *ops, struct sk_buff *skb,
+ struct genl_info *info)
+{
+ struct net *net = genl_info_net(info);
+ struct net_device *soft_iface;
+ struct batadv_priv *bat_priv;
+
+ if (ops->internal_flags & BATADV_FLAG_NEED_MESH) {
+ soft_iface = batadv_get_softif_from_info(net, info);
+ if (IS_ERR(soft_iface))
+ return PTR_ERR(soft_iface);
+
+ bat_priv = netdev_priv(soft_iface);
+ info->user_ptr[0] = bat_priv;
+ }
+
+ return 0;
+}
+
+/**
+ * batadv_post_doit() - End batman-adv genl doit request
+ * @ops: requested netlink operation
+ * @skb: Netlink message with request data
+ * @info: receiver information
+ */
+static void batadv_post_doit(const struct genl_ops *ops, struct sk_buff *skb,
+ struct genl_info *info)
+{
+ struct batadv_priv *bat_priv;
+
+ if (ops->internal_flags & BATADV_FLAG_NEED_MESH && info->user_ptr[0]) {
+ bat_priv = info->user_ptr[0];
+ dev_put(bat_priv->soft_iface);
+ }
+}
+
static const struct genl_ops batadv_netlink_ops[] = {
{
.cmd = BATADV_CMD_GET_MESH_INFO,
@@ -557,12 +610,14 @@ static const struct genl_ops batadv_netlink_ops[] = {
.flags = GENL_ADMIN_PERM,
.policy = batadv_netlink_policy,
.doit = batadv_netlink_tp_meter_start,
+ .internal_flags = BATADV_FLAG_NEED_MESH,
},
{
.cmd = BATADV_CMD_TP_METER_CANCEL,
.flags = GENL_ADMIN_PERM,
.policy = batadv_netlink_policy,
.doit = batadv_netlink_tp_meter_cancel,
+ .internal_flags = BATADV_FLAG_NEED_MESH,
},
{
.cmd = BATADV_CMD_GET_ROUTING_ALGOS,
@@ -639,6 +694,8 @@ struct genl_family batadv_netlink_family __ro_after_init = {
.version = 1,
.maxattr = BATADV_ATTR_MAX,
.netnsok = true,
+ .pre_doit = batadv_pre_doit,
+ .post_doit = batadv_post_doit,
.module = THIS_MODULE,
.ops = batadv_netlink_ops,
.n_ops = ARRAY_SIZE(batadv_netlink_ops),
--
2.20.1