batman-adv: Prepare framework for vlan genl config

The batman-adv configuration interface was implemented solely using sysfs.
This approach was condemned by non-batadv developers as "huge mistake".
Instead a netlink/genl based implementation was suggested.

Beside the mesh/soft-interface specific configuration, the VLANs on top of
the mesh/soft-interface have configuration settings. The genl interface
reflects this by allowing to get/set it using the vlan specific commands
BATADV_CMD_GET_VLAN/BATADV_CMD_SET_VLAN.

The set command BATADV_CMD_SET_MESH will also notify interested userspace
listeners of the "config" mcast group using the BATADV_CMD_SET_VLAN command
message type that settings might have been changed and what the current
values are.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

diff --git a/include/uapi/linux/batman_adv.h b/include/uapi/linux/batman_adv.h
index 62456a0..10f3cc3 100644 (file)
--- a/include/uapi/linux/batman_adv.h
+++ b/include/uapi/linux/batman_adv.h
@@ -345,6 +345,11 @@ enum batadv_nl_attrs {
         */
        BATADV_ATTR_MCAST_FLAGS_PRIV,
 
+       /**
+        * @BATADV_ATTR_VLANID: VLAN id on top of soft interface
+        */
+       BATADV_ATTR_VLANID,
+
        /* add attributes above here, update the policy in netlink.c */
 
        /**
@@ -465,6 +470,18 @@ enum batadv_nl_commands {
         */
        BATADV_CMD_SET_HARDIF,
 
+       /**
+        * @BATADV_CMD_GET_VLAN: Get attributes from a VLAN of the
+        *  current softif
+        */
+       BATADV_CMD_GET_VLAN,
+
+       /**
+        * @BATADV_CMD_SET_VLAN: Set attributes for VLAN of the
+        *  current softif
+        */
+       BATADV_CMD_SET_VLAN,
+
        /* add new commands above here */
 
        /**

diff --git a/net/batman-adv/netlink.c b/net/batman-adv/netlink.c
index a184e42..d40913b 100644 (file)
--- a/net/batman-adv/netlink.c
+++ b/net/batman-adv/netlink.c
@@ -30,6 +30,7 @@
 #include <linux/genetlink.h>
 #include <linux/gfp.h>
 #include <linux/if_ether.h>
+#include <linux/if_vlan.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
@@ -84,6 +85,13 @@ enum batadv_genl_ops_flags {
         *  saved in info->user_ptr[1]
         */
        BATADV_FLAG_NEED_HARDIF = BIT(1),
+
+       /**
+        * @BATADV_FLAG_NEED_VLAN: request requires valid vlan in
+        *  attribute BATADV_ATTR_VLANID and expects a pointer to it to be
+        *  saved in info->user_ptr[1]
+        */
+       BATADV_FLAG_NEED_VLAN = BIT(2),
 };
 
 static const struct genl_multicast_group batadv_netlink_mcgrps[] = {
@@ -130,6 +138,7 @@ static const struct nla_policy batadv_netlink_policy[NUM_BATADV_ATTR] = {
        [BATADV_ATTR_DAT_CACHE_VID]             = { .type = NLA_U16 },
        [BATADV_ATTR_MCAST_FLAGS]               = { .type = NLA_U32 },
        [BATADV_ATTR_MCAST_FLAGS_PRIV]          = { .type = NLA_U32 },
+       [BATADV_ATTR_VLANID]                    = { .type = NLA_U16 },
 };
 
 /**
@@ -653,6 +662,123 @@ batadv_netlink_dump_hardif(struct sk_buff *msg, struct netlink_callback *cb)
        return msg->len;
 }
 
+/**
+ * batadv_netlink_vlan_fill() - Fill message with vlan attributes
+ * @msg: Netlink message to dump into
+ * @bat_priv: the bat priv with all the soft interface information
+ * @vlan: vlan which was modified
+ * @cmd: type of message to generate
+ * @portid: Port making netlink request
+ * @seq: sequence number for message
+ * @flags: Additional flags for message
+ *
+ * Return: 0 on success or negative error number in case of failure
+ */
+static int batadv_netlink_vlan_fill(struct sk_buff *msg,
+                                   struct batadv_priv *bat_priv,
+                                   struct batadv_softif_vlan *vlan,
+                                   enum batadv_nl_commands cmd,
+                                   u32 portid, u32 seq, int flags)
+{
+       void *hdr;
+
+       hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family, flags, cmd);
+       if (!hdr)
+               return -ENOBUFS;
+
+       if (nla_put_u32(msg, BATADV_ATTR_MESH_IFINDEX,
+                       bat_priv->soft_iface->ifindex))
+               goto nla_put_failure;
+
+       if (nla_put_u32(msg, BATADV_ATTR_VLANID, vlan->vid & VLAN_VID_MASK))
+               goto nla_put_failure;
+
+       genlmsg_end(msg, hdr);
+       return 0;
+
+nla_put_failure:
+       genlmsg_cancel(msg, hdr);
+       return -EMSGSIZE;
+}
+
+/**
+ * batadv_netlink_notify_vlan() - send vlan attributes to listener
+ * @bat_priv: the bat priv with all the soft interface information
+ * @vlan: vlan which was modified
+ *
+ * Return: 0 on success, < 0 on error
+ */
+static int batadv_netlink_notify_vlan(struct batadv_priv *bat_priv,
+                                     struct batadv_softif_vlan *vlan)
+{
+       struct sk_buff *msg;
+       int ret;
+
+       msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+       if (!msg)
+               return -ENOMEM;
+
+       ret = batadv_netlink_vlan_fill(msg, bat_priv, vlan,
+                                      BATADV_CMD_SET_VLAN, 0, 0, 0);
+       if (ret < 0) {
+               nlmsg_free(msg);
+               return ret;
+       }
+
+       genlmsg_multicast_netns(&batadv_netlink_family,
+                               dev_net(bat_priv->soft_iface), msg, 0,
+                               BATADV_NL_MCGRP_CONFIG, GFP_KERNEL);
+
+       return 0;
+}
+
+/**
+ * batadv_netlink_get_vlan() - Get vlan attributes
+ * @skb: Netlink message with request data
+ * @info: receiver information
+ *
+ * Return: 0 on success or negative error number in case of failure
+ */
+static int batadv_netlink_get_vlan(struct sk_buff *skb, struct genl_info *info)
+{
+       struct batadv_softif_vlan *vlan = info->user_ptr[1];
+       struct batadv_priv *bat_priv = info->user_ptr[0];
+       struct sk_buff *msg;
+       int ret;
+
+       msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+       if (!msg)
+               return -ENOMEM;
+
+       ret = batadv_netlink_vlan_fill(msg, bat_priv, vlan, BATADV_CMD_GET_VLAN,
+                                      info->snd_portid, info->snd_seq, 0);
+       if (ret < 0) {
+               nlmsg_free(msg);
+               return ret;
+       }
+
+       ret = genlmsg_reply(msg, info);
+
+       return ret;
+}
+
+/**
+ * batadv_netlink_set_vlan() - Get vlan attributes
+ * @skb: Netlink message with request data
+ * @info: receiver information
+ *
+ * Return: 0 on success or negative error number in case of failure
+ */
+static int batadv_netlink_set_vlan(struct sk_buff *skb, struct genl_info *info)
+{
+       struct batadv_softif_vlan *vlan = info->user_ptr[1];
+       struct batadv_priv *bat_priv = info->user_ptr[0];
+
+       batadv_netlink_notify_vlan(bat_priv, vlan);
+
+       return 0;
+}
+
 /**
  * batadv_get_softif_from_info() - Retrieve soft interface from genl attributes
  * @net: the applicable net namespace
@@ -733,6 +859,34 @@ err_put_harddev:
        return ERR_PTR(-EINVAL);
 }
 
+/**
+ * batadv_get_vlan_from_info() - Retrieve vlan from genl attributes
+ * @bat_priv: the bat priv with all the soft interface information
+ * @net: the applicable net namespace
+ * @info: receiver information
+ *
+ * Return: Pointer to vlan on success (with increased refcnt), error pointer
+ *  on error
+ */
+static struct batadv_softif_vlan *
+batadv_get_vlan_from_info(struct batadv_priv *bat_priv, struct net *net,
+                         struct genl_info *info)
+{
+       struct batadv_softif_vlan *vlan;
+       u16 vid;
+
+       if (!info->attrs[BATADV_ATTR_VLANID])
+               return ERR_PTR(-EINVAL);
+
+       vid = nla_get_u16(info->attrs[BATADV_ATTR_VLANID]);
+
+       vlan = batadv_softif_vlan_get(bat_priv, vid | BATADV_VLAN_HAS_TAG);
+       if (!vlan)
+               return ERR_PTR(-ENOENT);
+
+       return vlan;
+}
+
 /**
  * batadv_pre_doit() - Prepare batman-adv genl doit request
  * @ops: requested netlink operation
@@ -747,16 +901,17 @@ static int batadv_pre_doit(const struct genl_ops *ops, struct sk_buff *skb,
        struct net *net = genl_info_net(info);
        struct batadv_hard_iface *hard_iface;
        struct batadv_priv *bat_priv = NULL;
+       struct batadv_softif_vlan *vlan;
        struct net_device *soft_iface;
        u8 user_ptr1_flags;
        u8 mesh_dep_flags;
        int ret;
 
-       user_ptr1_flags = BATADV_FLAG_NEED_HARDIF;
+       user_ptr1_flags = BATADV_FLAG_NEED_HARDIF | BATADV_FLAG_NEED_VLAN;
        if (WARN_ON(hweight8(ops->internal_flags & user_ptr1_flags) > 1))
                return -EINVAL;
 
-       mesh_dep_flags = BATADV_FLAG_NEED_HARDIF;
+       mesh_dep_flags = BATADV_FLAG_NEED_HARDIF | BATADV_FLAG_NEED_VLAN;
        if (WARN_ON((ops->internal_flags & mesh_dep_flags) &&
                    (~ops->internal_flags & BATADV_FLAG_NEED_MESH)))
                return -EINVAL;
@@ -780,6 +935,16 @@ static int batadv_pre_doit(const struct genl_ops *ops, struct sk_buff *skb,
                info->user_ptr[1] = hard_iface;
        }
 
+       if (ops->internal_flags & BATADV_FLAG_NEED_VLAN) {
+               vlan = batadv_get_vlan_from_info(bat_priv, net, info);
+               if (IS_ERR(vlan)) {
+                       ret = PTR_ERR(vlan);
+                       goto err_put_softif;
+               }
+
+               info->user_ptr[1] = vlan;
+       }
+
        return 0;
 
 err_put_softif:
@@ -799,6 +964,7 @@ static void batadv_post_doit(const struct genl_ops *ops, struct sk_buff *skb,
                             struct genl_info *info)
 {
        struct batadv_hard_iface *hard_iface;
+       struct batadv_softif_vlan *vlan;
        struct batadv_priv *bat_priv;
 
        if (ops->internal_flags & BATADV_FLAG_NEED_HARDIF &&
@@ -808,6 +974,11 @@ static void batadv_post_doit(const struct genl_ops *ops, struct sk_buff *skb,
                batadv_hardif_put(hard_iface);
        }
 
+       if (ops->internal_flags & BATADV_FLAG_NEED_VLAN && info->user_ptr[1]) {
+               vlan = info->user_ptr[1];
+               batadv_softif_vlan_put(vlan);
+       }
+
        if (ops->internal_flags & BATADV_FLAG_NEED_MESH && info->user_ptr[0]) {
                bat_priv = info->user_ptr[0];
                dev_put(bat_priv->soft_iface);
@@ -920,6 +1091,22 @@ static const struct genl_ops batadv_netlink_ops[] = {
                .internal_flags = BATADV_FLAG_NEED_MESH |
                                  BATADV_FLAG_NEED_HARDIF,
        },
+       {
+               .cmd = BATADV_CMD_GET_VLAN,
+               /* can be retrieved by unprivileged users */
+               .policy = batadv_netlink_policy,
+               .doit = batadv_netlink_get_vlan,
+               .internal_flags = BATADV_FLAG_NEED_MESH |
+                                 BATADV_FLAG_NEED_VLAN,
+       },
+       {
+               .cmd = BATADV_CMD_SET_VLAN,
+               .flags = GENL_ADMIN_PERM,
+               .policy = batadv_netlink_policy,
+               .doit = batadv_netlink_set_vlan,
+               .internal_flags = BATADV_FLAG_NEED_MESH |
+                                 BATADV_FLAG_NEED_VLAN,
+       },
 };
 
 struct genl_family batadv_netlink_family __ro_after_init = {