diff mbox series

[1/2] batman-adv: add DAT cache netlink support

Message ID 20180227081016.13122-1-linus.luessing@c0d3.blue
State Superseded, archived
Delegated to: Simon Wunderlich
Headers show
Series [1/2] batman-adv: add DAT cache netlink support | expand

Commit Message

Linus Lüssing Feb. 27, 2018, 8:10 a.m. UTC
Dump the list of DAT cache entries via the netlink socket.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
---
 include/uapi/linux/batman_adv.h        |  20 +++++
 net/batman-adv/distributed-arp-table.c | 151 +++++++++++++++++++++++++++++++++
 net/batman-adv/distributed-arp-table.h |   7 ++
 net/batman-adv/netlink.c               |  10 +++
 4 files changed, 188 insertions(+)

Comments

Sven Eckelmann March 4, 2018, 12:36 p.m. UTC | #1
> diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c
> index 19b15de4..aca34e95 100644
> --- a/net/batman-adv/distributed-arp-table.c
> +++ b/net/batman-adv/distributed-arp-table.c
> @@ -43,13 +43,18 @@
>  #include <linux/string.h>
>  #include <linux/workqueue.h>
>  #include <net/arp.h>
> +#include <net/genetlink.h>
> +#include <net/netlink.h>
> +#include <net/sock.h>
>  
>  #include "bridge_loop_avoidance.h"
>  #include "hard-interface.h"
>  #include "hash.h"
>  #include "log.h"
> +#include "netlink.h"
>  #include "originator.h"
>  #include "send.h"
> +#include "soft-interface.h"
>  #include "translation-table.h"
>  #include "tvlv.h"

Please also add:

* #include <linux/netlink.h> for
  - netlink_callback
  - NETLINK_CB
* #include <uapi/linux/batman_adv.h>
  - for all the new batadv genl attributes

> diff --git a/net/batman-adv/distributed-arp-table.h b/net/batman-adv/distributed-arp-table.h
> index e24aa960..23d11494 100644
> --- a/net/batman-adv/distributed-arp-table.h
> +++ b/net/batman-adv/distributed-arp-table.h

Please also add forward declaration for "struct netlink_callback;" (above 
"struct seq_file;").

Kind regards,
	Sven
Sven Eckelmann March 4, 2018, 4:41 p.m. UTC | #2
On Dienstag, 27. Februar 2018 09:10:15 CET Linus Lüssing wrote:
> +       if (nla_put_u32(msg, BATADV_ATTR_DC_ADDRESS, ip) ||
> +           nla_put(msg, BATADV_ATTR_DC_HWADDRESS, ETH_ALEN,
> +                   dat_entry->mac_addr) ||
> +           nla_put_u16(msg, BATADV_ATTR_DC_VID, dat_entry->vid) ||
> +           nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS, msecs)) {
> +               genlmsg_cancel(msg, hdr);
> +               return -EMSGSIZE;

Just found that there is a function to send IPv4 addresses 
(BATADV_ATTR_DC_ADDRESS) to userspace: nla_put_in_addr. It requires that you 
provide the IPv4 address in __be32 format and not in host format.  It is maybe 
a good idea to use it and keep it more consistent with the rest of the kernel. 

Don't forget to also adjust the batctl code (remove the htonl).

Kind regards,
	Sven
Sven Eckelmann March 4, 2018, 5:34 p.m. UTC | #3
On Sonntag, 4. März 2018 17:41:26 CET Sven Eckelmann wrote:
> On Dienstag, 27. Februar 2018 09:10:15 CET Linus Lüssing wrote:
> > +       if (nla_put_u32(msg, BATADV_ATTR_DC_ADDRESS, ip) ||
> > +           nla_put(msg, BATADV_ATTR_DC_HWADDRESS, ETH_ALEN,
> > +                   dat_entry->mac_addr) ||
> > +           nla_put_u16(msg, BATADV_ATTR_DC_VID, dat_entry->vid) ||
> > +           nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS, msecs)) {
> > +               genlmsg_cancel(msg, hdr);
> > +               return -EMSGSIZE;
> 
> Just found that there is a function to send IPv4 addresses 
> (BATADV_ATTR_DC_ADDRESS) to userspace: nla_put_in_addr. It requires that you 
> provide the IPv4 address in __be32 format and not in host format.  It is maybe 
> a good idea to use it and keep it more consistent with the rest of the kernel. 

Btw. this function was introduced with linux-4.1 [1] and older kernels will 
need compat code for it.

Kind regards,
	Sven

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=930345ea630405aa6e6f42efcb149c3f360a6b67
diff mbox series

Patch

diff --git a/include/uapi/linux/batman_adv.h b/include/uapi/linux/batman_adv.h
index 56ae2893..85c9fe8a 100644
--- a/include/uapi/linux/batman_adv.h
+++ b/include/uapi/linux/batman_adv.h
@@ -272,6 +272,21 @@  enum batadv_nl_attrs {
 	 */
 	BATADV_ATTR_BLA_CRC,
 
+	/**
+	 * @BATADV_ATTR_DC_ADDRESS: Client IPv4 address
+	 */
+	BATADV_ATTR_DC_ADDRESS,
+
+	/**
+	 * @BATADV_ATTR_DC_HWADDRESS: Client MAC address
+	 */
+	BATADV_ATTR_DC_HWADDRESS,
+
+	/**
+	 * @BATADV_ATTR_DC_VID: VLAN ID
+	 */
+	BATADV_ATTR_DC_VID,
+
 	/* add attributes above here, update the policy in netlink.c */
 
 	/**
@@ -361,6 +376,11 @@  enum batadv_nl_commands {
 	 */
 	BATADV_CMD_GET_BLA_BACKBONE,
 
+	/**
+	 * @BATADV_CMD_GET_DAT_CACHE: Query list of DAT cache entries
+	 */
+	BATADV_CMD_GET_DAT_CACHE,
+
 	/* add new commands above here */
 
 	/**
diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c
index 19b15de4..aca34e95 100644
--- a/net/batman-adv/distributed-arp-table.c
+++ b/net/batman-adv/distributed-arp-table.c
@@ -43,13 +43,18 @@ 
 #include <linux/string.h>
 #include <linux/workqueue.h>
 #include <net/arp.h>
+#include <net/genetlink.h>
+#include <net/netlink.h>
+#include <net/sock.h>
 
 #include "bridge_loop_avoidance.h"
 #include "hard-interface.h"
 #include "hash.h"
 #include "log.h"
+#include "netlink.h"
 #include "originator.h"
 #include "send.h"
+#include "soft-interface.h"
 #include "translation-table.h"
 #include "tvlv.h"
 
@@ -852,6 +857,152 @@  int batadv_dat_cache_seq_print_text(struct seq_file *seq, void *offset)
 #endif
 
 /**
+ * batadv_dat_cache_dump_entry() - dump one entry of the DAT cache table to a
+ *  netlink socket
+ * @msg: buffer for the message
+ * @portid: netlink port
+ * @seq: Sequence number of netlink message
+ * @dat_entry: entry to dump
+ *
+ * Return: 0 or error code.
+ */
+static int
+batadv_dat_cache_dump_entry(struct sk_buff *msg, u32 portid, u32 seq,
+			    struct batadv_dat_entry *dat_entry)
+{
+	int msecs;
+	void *hdr;
+	u32 ip;
+
+	hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family,
+			  NLM_F_MULTI, BATADV_CMD_GET_DAT_CACHE);
+	if (!hdr)
+		return -ENOBUFS;
+
+	msecs = jiffies_to_msecs(jiffies - dat_entry->last_update);
+	ip = ntohl(dat_entry->ip);
+
+	if (nla_put_u32(msg, BATADV_ATTR_DC_ADDRESS, ip) ||
+	    nla_put(msg, BATADV_ATTR_DC_HWADDRESS, ETH_ALEN,
+		    dat_entry->mac_addr) ||
+	    nla_put_u16(msg, BATADV_ATTR_DC_VID, dat_entry->vid) ||
+	    nla_put_u32(msg, BATADV_ATTR_LAST_SEEN_MSECS, msecs)) {
+		genlmsg_cancel(msg, hdr);
+		return -EMSGSIZE;
+	}
+
+	genlmsg_end(msg, hdr);
+	return 0;
+}
+
+/**
+ * batadv_dat_cache_dump_bucket() - dump one bucket of the DAT cache table to
+ *  a netlink socket
+ * @msg: buffer for the message
+ * @portid: netlink port
+ * @seq: Sequence number of netlink message
+ * @head: bucket to dump
+ * @idx_skip: How many entries to skip
+ *
+ * Return: 0 or error code.
+ */
+static int
+batadv_dat_cache_dump_bucket(struct sk_buff *msg, u32 portid, u32 seq,
+			     struct hlist_head *head, int *idx_skip)
+{
+	struct batadv_dat_entry *dat_entry;
+	int idx = 0;
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(dat_entry, head, hash_entry) {
+		if (idx < *idx_skip)
+			goto skip;
+
+		if (batadv_dat_cache_dump_entry(msg, portid, seq,
+						dat_entry)) {
+			rcu_read_unlock();
+			*idx_skip = idx;
+
+			return -EMSGSIZE;
+		}
+
+skip:
+		idx++;
+	}
+	rcu_read_unlock();
+
+	return 0;
+}
+
+/**
+ * batadv_dat_cache_dump() - dump DAT cache table to a netlink socket
+ * @msg: buffer for the message
+ * @cb: callback structure containing arguments
+ *
+ * Return: message length.
+ */
+int batadv_dat_cache_dump(struct sk_buff *msg, struct netlink_callback *cb)
+{
+	struct batadv_hard_iface *primary_if = NULL;
+	int portid = NETLINK_CB(cb->skb).portid;
+	struct net *net = sock_net(cb->skb->sk);
+	struct net_device *soft_iface;
+	struct batadv_hashtable *hash;
+	struct batadv_priv *bat_priv;
+	int bucket = cb->args[0];
+	struct hlist_head *head;
+	int idx = cb->args[1];
+	int ifindex;
+	int ret = 0;
+
+	ifindex = batadv_netlink_get_ifindex(cb->nlh,
+					     BATADV_ATTR_MESH_IFINDEX);
+	if (!ifindex)
+		return -EINVAL;
+
+	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);
+	hash = bat_priv->dat.hash;
+
+	primary_if = batadv_primary_if_get_selected(bat_priv);
+	if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	while (bucket < hash->size) {
+		head = &hash->table[bucket];
+
+		if (batadv_dat_cache_dump_bucket(msg, portid,
+						 cb->nlh->nlmsg_seq, head,
+						 &idx))
+			break;
+
+		bucket++;
+		idx = 0;
+	}
+
+	cb->args[0] = bucket;
+	cb->args[1] = idx;
+
+	ret = msg->len;
+
+out:
+	if (primary_if)
+		batadv_hardif_put(primary_if);
+
+	if (soft_iface)
+		dev_put(soft_iface);
+
+	return ret;
+}
+
+/**
  * batadv_arp_get_type() - parse an ARP packet and gets the type
  * @bat_priv: the bat priv with all the soft interface information
  * @skb: packet to analyse
diff --git a/net/batman-adv/distributed-arp-table.h b/net/batman-adv/distributed-arp-table.h
index e24aa960..23d11494 100644
--- a/net/batman-adv/distributed-arp-table.h
+++ b/net/batman-adv/distributed-arp-table.h
@@ -81,6 +81,7 @@  batadv_dat_init_own_addr(struct batadv_priv *bat_priv,
 int batadv_dat_init(struct batadv_priv *bat_priv);
 void batadv_dat_free(struct batadv_priv *bat_priv);
 int batadv_dat_cache_seq_print_text(struct seq_file *seq, void *offset);
+int batadv_dat_cache_dump(struct sk_buff *msg, struct netlink_callback *cb);
 
 /**
  * batadv_dat_inc_counter() - increment the correct DAT packet counter
@@ -169,6 +170,12 @@  static inline void batadv_dat_free(struct batadv_priv *bat_priv)
 {
 }
 
+static inline int
+batadv_dat_cache_dump(struct sk_buff *msg, struct netlink_callback *cb)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline void batadv_dat_inc_counter(struct batadv_priv *bat_priv,
 					  u8 subtype)
 {
diff --git a/net/batman-adv/netlink.c b/net/batman-adv/netlink.c
index 129af56b..7812b531 100644
--- a/net/batman-adv/netlink.c
+++ b/net/batman-adv/netlink.c
@@ -45,6 +45,7 @@ 
 
 #include "bat_algo.h"
 #include "bridge_loop_avoidance.h"
+#include "distributed-arp-table.h"
 #include "gateway_client.h"
 #include "hard-interface.h"
 #include "originator.h"
@@ -97,6 +98,9 @@  static const struct nla_policy batadv_netlink_policy[NUM_BATADV_ATTR] = {
 	[BATADV_ATTR_BLA_VID]		= { .type = NLA_U16 },
 	[BATADV_ATTR_BLA_BACKBONE]	= { .len = ETH_ALEN },
 	[BATADV_ATTR_BLA_CRC]		= { .type = NLA_U16 },
+	[BATADV_ATTR_DC_ADDRESS]	= { .type = NLA_U32 },
+	[BATADV_ATTR_DC_HWADDRESS]	= { .len = ETH_ALEN },
+	[BATADV_ATTR_DC_VID]		= { .type = NLA_U16 },
 };
 
 /**
@@ -604,6 +608,12 @@  static const struct genl_ops batadv_netlink_ops[] = {
 		.policy = batadv_netlink_policy,
 		.dumpit = batadv_bla_backbone_dump,
 	},
+	{
+		.cmd = BATADV_CMD_GET_DAT_CACHE,
+		.flags = GENL_ADMIN_PERM,
+		.policy = batadv_netlink_policy,
+		.dumpit = batadv_dat_cache_dump,
+	},
 
 };