linux/net/batman-adv/main.c
Sven Eckelmann fb69be6979 batman-adv: Add inconsistent hardif netlink dump detection
The netlink dump functionality transfers a large number of entries from the
kernel to userspace. It is rather likely that the transfer has to
interrupted and later continued. During that time, it can happen that
either new entries are added or removed. The userspace could than either
receive some entries multiple times or miss entries.

Commit 670dc2833d ("netlink: advertise incomplete dumps") introduced a
mechanism to inform userspace about this problem. Userspace can then decide
whether it is necessary or not to retry dumping the information again.

The netlink dump functions have to be switched to exclusive locks to avoid
changes while the current message is prepared. And an external generation
sequence counter is introduced which tracks all modifications of the list.

Reported-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-11-12 10:41:51 +01:00

692 lines
19 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2007-2018 B.A.T.M.A.N. contributors:
*
* Marek Lindner, Simon Wunderlich
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "main.h"
#include <linux/atomic.h>
#include <linux/build_bug.h>
#include <linux/byteorder/generic.h>
#include <linux/crc32c.h>
#include <linux/errno.h>
#include <linux/genetlink.h>
#include <linux/gfp.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/init.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/printk.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/seq_file.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/workqueue.h>
#include <net/dsfield.h>
#include <net/rtnetlink.h>
#include <uapi/linux/batadv_packet.h>
#include <uapi/linux/batman_adv.h>
#include "bat_algo.h"
#include "bat_iv_ogm.h"
#include "bat_v.h"
#include "bridge_loop_avoidance.h"
#include "debugfs.h"
#include "distributed-arp-table.h"
#include "gateway_client.h"
#include "gateway_common.h"
#include "hard-interface.h"
#include "icmp_socket.h"
#include "log.h"
#include "multicast.h"
#include "netlink.h"
#include "network-coding.h"
#include "originator.h"
#include "routing.h"
#include "send.h"
#include "soft-interface.h"
#include "tp_meter.h"
#include "translation-table.h"
/* List manipulations on hardif_list have to be rtnl_lock()'ed,
* list traversals just rcu-locked
*/
struct list_head batadv_hardif_list;
unsigned int batadv_hardif_generation;
static int (*batadv_rx_handler[256])(struct sk_buff *skb,
struct batadv_hard_iface *recv_if);
unsigned char batadv_broadcast_addr[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
struct workqueue_struct *batadv_event_workqueue;
static void batadv_recv_handler_init(void);
static int __init batadv_init(void)
{
int ret;
ret = batadv_tt_cache_init();
if (ret < 0)
return ret;
INIT_LIST_HEAD(&batadv_hardif_list);
batadv_algo_init();
batadv_recv_handler_init();
batadv_v_init();
batadv_iv_init();
batadv_nc_init();
batadv_tp_meter_init();
batadv_event_workqueue = create_singlethread_workqueue("bat_events");
if (!batadv_event_workqueue)
goto err_create_wq;
batadv_socket_init();
batadv_debugfs_init();
register_netdevice_notifier(&batadv_hard_if_notifier);
rtnl_link_register(&batadv_link_ops);
batadv_netlink_register();
pr_info("B.A.T.M.A.N. advanced %s (compatibility version %i) loaded\n",
BATADV_SOURCE_VERSION, BATADV_COMPAT_VERSION);
return 0;
err_create_wq:
batadv_tt_cache_destroy();
return -ENOMEM;
}
static void __exit batadv_exit(void)
{
batadv_debugfs_destroy();
batadv_netlink_unregister();
rtnl_link_unregister(&batadv_link_ops);
unregister_netdevice_notifier(&batadv_hard_if_notifier);
batadv_hardif_remove_interfaces();
flush_workqueue(batadv_event_workqueue);
destroy_workqueue(batadv_event_workqueue);
batadv_event_workqueue = NULL;
rcu_barrier();
batadv_tt_cache_destroy();
}
/**
* batadv_mesh_init() - Initialize soft interface
* @soft_iface: netdev struct of the soft interface
*
* Return: 0 on success or negative error number in case of failure
*/
int batadv_mesh_init(struct net_device *soft_iface)
{
struct batadv_priv *bat_priv = netdev_priv(soft_iface);
int ret;
spin_lock_init(&bat_priv->forw_bat_list_lock);
spin_lock_init(&bat_priv->forw_bcast_list_lock);
spin_lock_init(&bat_priv->tt.changes_list_lock);
spin_lock_init(&bat_priv->tt.req_list_lock);
spin_lock_init(&bat_priv->tt.roam_list_lock);
spin_lock_init(&bat_priv->tt.last_changeset_lock);
spin_lock_init(&bat_priv->tt.commit_lock);
spin_lock_init(&bat_priv->gw.list_lock);
#ifdef CONFIG_BATMAN_ADV_MCAST
spin_lock_init(&bat_priv->mcast.want_lists_lock);
#endif
spin_lock_init(&bat_priv->tvlv.container_list_lock);
spin_lock_init(&bat_priv->tvlv.handler_list_lock);
spin_lock_init(&bat_priv->softif_vlan_list_lock);
spin_lock_init(&bat_priv->tp_list_lock);
INIT_HLIST_HEAD(&bat_priv->forw_bat_list);
INIT_HLIST_HEAD(&bat_priv->forw_bcast_list);
INIT_HLIST_HEAD(&bat_priv->gw.gateway_list);
#ifdef CONFIG_BATMAN_ADV_MCAST
INIT_HLIST_HEAD(&bat_priv->mcast.want_all_unsnoopables_list);
INIT_HLIST_HEAD(&bat_priv->mcast.want_all_ipv4_list);
INIT_HLIST_HEAD(&bat_priv->mcast.want_all_ipv6_list);
#endif
INIT_LIST_HEAD(&bat_priv->tt.changes_list);
INIT_HLIST_HEAD(&bat_priv->tt.req_list);
INIT_LIST_HEAD(&bat_priv->tt.roam_list);
#ifdef CONFIG_BATMAN_ADV_MCAST
INIT_HLIST_HEAD(&bat_priv->mcast.mla_list);
#endif
INIT_HLIST_HEAD(&bat_priv->tvlv.container_list);
INIT_HLIST_HEAD(&bat_priv->tvlv.handler_list);
INIT_HLIST_HEAD(&bat_priv->softif_vlan_list);
INIT_HLIST_HEAD(&bat_priv->tp_list);
bat_priv->gw.generation = 0;
ret = batadv_v_mesh_init(bat_priv);
if (ret < 0)
goto err;
ret = batadv_originator_init(bat_priv);
if (ret < 0)
goto err;
ret = batadv_tt_init(bat_priv);
if (ret < 0)
goto err;
ret = batadv_bla_init(bat_priv);
if (ret < 0)
goto err;
ret = batadv_dat_init(bat_priv);
if (ret < 0)
goto err;
ret = batadv_nc_mesh_init(bat_priv);
if (ret < 0)
goto err;
batadv_gw_init(bat_priv);
batadv_mcast_init(bat_priv);
atomic_set(&bat_priv->gw.reselect, 0);
atomic_set(&bat_priv->mesh_state, BATADV_MESH_ACTIVE);
return 0;
err:
batadv_mesh_free(soft_iface);
return ret;
}
/**
* batadv_mesh_free() - Deinitialize soft interface
* @soft_iface: netdev struct of the soft interface
*/
void batadv_mesh_free(struct net_device *soft_iface)
{
struct batadv_priv *bat_priv = netdev_priv(soft_iface);
atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
batadv_purge_outstanding_packets(bat_priv, NULL);
batadv_gw_node_free(bat_priv);
batadv_v_mesh_free(bat_priv);
batadv_nc_mesh_free(bat_priv);
batadv_dat_free(bat_priv);
batadv_bla_free(bat_priv);
batadv_mcast_free(bat_priv);
/* Free the TT and the originator tables only after having terminated
* all the other depending components which may use these structures for
* their purposes.
*/
batadv_tt_free(bat_priv);
/* Since the originator table clean up routine is accessing the TT
* tables as well, it has to be invoked after the TT tables have been
* freed and marked as empty. This ensures that no cleanup RCU callbacks
* accessing the TT data are scheduled for later execution.
*/
batadv_originator_free(bat_priv);
batadv_gw_free(bat_priv);
free_percpu(bat_priv->bat_counters);
bat_priv->bat_counters = NULL;
atomic_set(&bat_priv->mesh_state, BATADV_MESH_INACTIVE);
}
/**
* batadv_is_my_mac() - check if the given mac address belongs to any of the
* real interfaces in the current mesh
* @bat_priv: the bat priv with all the soft interface information
* @addr: the address to check
*
* Return: 'true' if the mac address was found, false otherwise.
*/
bool batadv_is_my_mac(struct batadv_priv *bat_priv, const u8 *addr)
{
const struct batadv_hard_iface *hard_iface;
bool is_my_mac = false;
rcu_read_lock();
list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
if (hard_iface->if_status != BATADV_IF_ACTIVE)
continue;
if (hard_iface->soft_iface != bat_priv->soft_iface)
continue;
if (batadv_compare_eth(hard_iface->net_dev->dev_addr, addr)) {
is_my_mac = true;
break;
}
}
rcu_read_unlock();
return is_my_mac;
}
#ifdef CONFIG_BATMAN_ADV_DEBUGFS
/**
* batadv_seq_print_text_primary_if_get() - called from debugfs table printing
* function that requires the primary interface
* @seq: debugfs table seq_file struct
*
* Return: primary interface if found or NULL otherwise.
*/
struct batadv_hard_iface *
batadv_seq_print_text_primary_if_get(struct seq_file *seq)
{
struct net_device *net_dev = (struct net_device *)seq->private;
struct batadv_priv *bat_priv = netdev_priv(net_dev);
struct batadv_hard_iface *primary_if;
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if) {
seq_printf(seq,
"BATMAN mesh %s disabled - please specify interfaces to enable it\n",
net_dev->name);
goto out;
}
if (primary_if->if_status == BATADV_IF_ACTIVE)
goto out;
seq_printf(seq,
"BATMAN mesh %s disabled - primary interface not active\n",
net_dev->name);
batadv_hardif_put(primary_if);
primary_if = NULL;
out:
return primary_if;
}
#endif
/**
* batadv_max_header_len() - calculate maximum encapsulation overhead for a
* payload packet
*
* Return: the maximum encapsulation overhead in bytes.
*/
int batadv_max_header_len(void)
{
int header_len = 0;
header_len = max_t(int, header_len,
sizeof(struct batadv_unicast_packet));
header_len = max_t(int, header_len,
sizeof(struct batadv_unicast_4addr_packet));
header_len = max_t(int, header_len,
sizeof(struct batadv_bcast_packet));
#ifdef CONFIG_BATMAN_ADV_NC
header_len = max_t(int, header_len,
sizeof(struct batadv_coded_packet));
#endif
return header_len + ETH_HLEN;
}
/**
* batadv_skb_set_priority() - sets skb priority according to packet content
* @skb: the packet to be sent
* @offset: offset to the packet content
*
* This function sets a value between 256 and 263 (802.1d priority), which
* can be interpreted by the cfg80211 or other drivers.
*/
void batadv_skb_set_priority(struct sk_buff *skb, int offset)
{
struct iphdr ip_hdr_tmp, *ip_hdr;
struct ipv6hdr ip6_hdr_tmp, *ip6_hdr;
struct ethhdr ethhdr_tmp, *ethhdr;
struct vlan_ethhdr *vhdr, vhdr_tmp;
u32 prio;
/* already set, do nothing */
if (skb->priority >= 256 && skb->priority <= 263)
return;
ethhdr = skb_header_pointer(skb, offset, sizeof(*ethhdr), &ethhdr_tmp);
if (!ethhdr)
return;
switch (ethhdr->h_proto) {
case htons(ETH_P_8021Q):
vhdr = skb_header_pointer(skb, offset + sizeof(*vhdr),
sizeof(*vhdr), &vhdr_tmp);
if (!vhdr)
return;
prio = ntohs(vhdr->h_vlan_TCI) & VLAN_PRIO_MASK;
prio = prio >> VLAN_PRIO_SHIFT;
break;
case htons(ETH_P_IP):
ip_hdr = skb_header_pointer(skb, offset + sizeof(*ethhdr),
sizeof(*ip_hdr), &ip_hdr_tmp);
if (!ip_hdr)
return;
prio = (ipv4_get_dsfield(ip_hdr) & 0xfc) >> 5;
break;
case htons(ETH_P_IPV6):
ip6_hdr = skb_header_pointer(skb, offset + sizeof(*ethhdr),
sizeof(*ip6_hdr), &ip6_hdr_tmp);
if (!ip6_hdr)
return;
prio = (ipv6_get_dsfield(ip6_hdr) & 0xfc) >> 5;
break;
default:
return;
}
skb->priority = prio + 256;
}
static int batadv_recv_unhandled_packet(struct sk_buff *skb,
struct batadv_hard_iface *recv_if)
{
kfree_skb(skb);
return NET_RX_DROP;
}
/* incoming packets with the batman ethertype received on any active hard
* interface
*/
/**
* batadv_batman_skb_recv() - Handle incoming message from an hard interface
* @skb: the received packet
* @dev: the net device that the packet was received on
* @ptype: packet type of incoming packet (ETH_P_BATMAN)
* @orig_dev: the original receive net device (e.g. bonded device)
*
* Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
*/
int batadv_batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *ptype,
struct net_device *orig_dev)
{
struct batadv_priv *bat_priv;
struct batadv_ogm_packet *batadv_ogm_packet;
struct batadv_hard_iface *hard_iface;
u8 idx;
hard_iface = container_of(ptype, struct batadv_hard_iface,
batman_adv_ptype);
/* Prevent processing a packet received on an interface which is getting
* shut down otherwise the packet may trigger de-reference errors
* further down in the receive path.
*/
if (!kref_get_unless_zero(&hard_iface->refcount))
goto err_out;
skb = skb_share_check(skb, GFP_ATOMIC);
/* skb was released by skb_share_check() */
if (!skb)
goto err_put;
/* packet should hold at least type and version */
if (unlikely(!pskb_may_pull(skb, 2)))
goto err_free;
/* expect a valid ethernet header here. */
if (unlikely(skb->mac_len != ETH_HLEN || !skb_mac_header(skb)))
goto err_free;
if (!hard_iface->soft_iface)
goto err_free;
bat_priv = netdev_priv(hard_iface->soft_iface);
if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
goto err_free;
/* discard frames on not active interfaces */
if (hard_iface->if_status != BATADV_IF_ACTIVE)
goto err_free;
batadv_ogm_packet = (struct batadv_ogm_packet *)skb->data;
if (batadv_ogm_packet->version != BATADV_COMPAT_VERSION) {
batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
"Drop packet: incompatible batman version (%i)\n",
batadv_ogm_packet->version);
goto err_free;
}
/* reset control block to avoid left overs from previous users */
memset(skb->cb, 0, sizeof(struct batadv_skb_cb));
idx = batadv_ogm_packet->packet_type;
(*batadv_rx_handler[idx])(skb, hard_iface);
batadv_hardif_put(hard_iface);
/* return NET_RX_SUCCESS in any case as we
* most probably dropped the packet for
* routing-logical reasons.
*/
return NET_RX_SUCCESS;
err_free:
kfree_skb(skb);
err_put:
batadv_hardif_put(hard_iface);
err_out:
return NET_RX_DROP;
}
static void batadv_recv_handler_init(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(batadv_rx_handler); i++)
batadv_rx_handler[i] = batadv_recv_unhandled_packet;
for (i = BATADV_UNICAST_MIN; i <= BATADV_UNICAST_MAX; i++)
batadv_rx_handler[i] = batadv_recv_unhandled_unicast_packet;
/* compile time checks for sizes */
BUILD_BUG_ON(sizeof(struct batadv_bla_claim_dst) != 6);
BUILD_BUG_ON(sizeof(struct batadv_ogm_packet) != 24);
BUILD_BUG_ON(sizeof(struct batadv_icmp_header) != 20);
BUILD_BUG_ON(sizeof(struct batadv_icmp_packet) != 20);
BUILD_BUG_ON(sizeof(struct batadv_icmp_packet_rr) != 116);
BUILD_BUG_ON(sizeof(struct batadv_unicast_packet) != 10);
BUILD_BUG_ON(sizeof(struct batadv_unicast_4addr_packet) != 18);
BUILD_BUG_ON(sizeof(struct batadv_frag_packet) != 20);
BUILD_BUG_ON(sizeof(struct batadv_bcast_packet) != 14);
BUILD_BUG_ON(sizeof(struct batadv_coded_packet) != 46);
BUILD_BUG_ON(sizeof(struct batadv_unicast_tvlv_packet) != 20);
BUILD_BUG_ON(sizeof(struct batadv_tvlv_hdr) != 4);
BUILD_BUG_ON(sizeof(struct batadv_tvlv_gateway_data) != 8);
BUILD_BUG_ON(sizeof(struct batadv_tvlv_tt_vlan_data) != 8);
BUILD_BUG_ON(sizeof(struct batadv_tvlv_tt_change) != 12);
BUILD_BUG_ON(sizeof(struct batadv_tvlv_roam_adv) != 8);
i = FIELD_SIZEOF(struct sk_buff, cb);
BUILD_BUG_ON(sizeof(struct batadv_skb_cb) > i);
/* broadcast packet */
batadv_rx_handler[BATADV_BCAST] = batadv_recv_bcast_packet;
/* unicast packets ... */
/* unicast with 4 addresses packet */
batadv_rx_handler[BATADV_UNICAST_4ADDR] = batadv_recv_unicast_packet;
/* unicast packet */
batadv_rx_handler[BATADV_UNICAST] = batadv_recv_unicast_packet;
/* unicast tvlv packet */
batadv_rx_handler[BATADV_UNICAST_TVLV] = batadv_recv_unicast_tvlv;
/* batman icmp packet */
batadv_rx_handler[BATADV_ICMP] = batadv_recv_icmp_packet;
/* Fragmented packets */
batadv_rx_handler[BATADV_UNICAST_FRAG] = batadv_recv_frag_packet;
}
/**
* batadv_recv_handler_register() - Register handler for batman-adv packet type
* @packet_type: batadv_packettype which should be handled
* @recv_handler: receive handler for the packet type
*
* Return: 0 on success or negative error number in case of failure
*/
int
batadv_recv_handler_register(u8 packet_type,
int (*recv_handler)(struct sk_buff *,
struct batadv_hard_iface *))
{
int (*curr)(struct sk_buff *skb,
struct batadv_hard_iface *recv_if);
curr = batadv_rx_handler[packet_type];
if (curr != batadv_recv_unhandled_packet &&
curr != batadv_recv_unhandled_unicast_packet)
return -EBUSY;
batadv_rx_handler[packet_type] = recv_handler;
return 0;
}
/**
* batadv_recv_handler_unregister() - Unregister handler for packet type
* @packet_type: batadv_packettype which should no longer be handled
*/
void batadv_recv_handler_unregister(u8 packet_type)
{
batadv_rx_handler[packet_type] = batadv_recv_unhandled_packet;
}
/**
* batadv_skb_crc32() - calculate CRC32 of the whole packet and skip bytes in
* the header
* @skb: skb pointing to fragmented socket buffers
* @payload_ptr: Pointer to position inside the head buffer of the skb
* marking the start of the data to be CRC'ed
*
* payload_ptr must always point to an address in the skb head buffer and not to
* a fragment.
*
* Return: big endian crc32c of the checksummed data
*/
__be32 batadv_skb_crc32(struct sk_buff *skb, u8 *payload_ptr)
{
u32 crc = 0;
unsigned int from;
unsigned int to = skb->len;
struct skb_seq_state st;
const u8 *data;
unsigned int len;
unsigned int consumed = 0;
from = (unsigned int)(payload_ptr - skb->data);
skb_prepare_seq_read(skb, from, to, &st);
while ((len = skb_seq_read(consumed, &data, &st)) != 0) {
crc = crc32c(crc, data, len);
consumed += len;
}
return htonl(crc);
}
/**
* batadv_get_vid() - extract the VLAN identifier from skb if any
* @skb: the buffer containing the packet
* @header_len: length of the batman header preceding the ethernet header
*
* Return: VID with the BATADV_VLAN_HAS_TAG flag when the packet embedded in the
* skb is vlan tagged. Otherwise BATADV_NO_FLAGS.
*/
unsigned short batadv_get_vid(struct sk_buff *skb, size_t header_len)
{
struct ethhdr *ethhdr = (struct ethhdr *)(skb->data + header_len);
struct vlan_ethhdr *vhdr;
unsigned short vid;
if (ethhdr->h_proto != htons(ETH_P_8021Q))
return BATADV_NO_FLAGS;
if (!pskb_may_pull(skb, header_len + VLAN_ETH_HLEN))
return BATADV_NO_FLAGS;
vhdr = (struct vlan_ethhdr *)(skb->data + header_len);
vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
vid |= BATADV_VLAN_HAS_TAG;
return vid;
}
/**
* batadv_vlan_ap_isola_get() - return AP isolation status for the given vlan
* @bat_priv: the bat priv with all the soft interface information
* @vid: the VLAN identifier for which the AP isolation attributed as to be
* looked up
*
* Return: true if AP isolation is on for the VLAN idenfied by vid, false
* otherwise
*/
bool batadv_vlan_ap_isola_get(struct batadv_priv *bat_priv, unsigned short vid)
{
bool ap_isolation_enabled = false;
struct batadv_softif_vlan *vlan;
/* if the AP isolation is requested on a VLAN, then check for its
* setting in the proper VLAN private data structure
*/
vlan = batadv_softif_vlan_get(bat_priv, vid);
if (vlan) {
ap_isolation_enabled = atomic_read(&vlan->ap_isolation);
batadv_softif_vlan_put(vlan);
}
return ap_isolation_enabled;
}
module_init(batadv_init);
module_exit(batadv_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR(BATADV_DRIVER_AUTHOR);
MODULE_DESCRIPTION(BATADV_DRIVER_DESC);
MODULE_SUPPORTED_DEVICE(BATADV_DRIVER_DEVICE);
MODULE_VERSION(BATADV_SOURCE_VERSION);
MODULE_ALIAS_RTNL_LINK("batadv");
MODULE_ALIAS_GENL_FAMILY(BATADV_NL_NAME);