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0001 // SPDX-License-Identifier: GPL-2.0
0002 /* Copyright (C) B.A.T.M.A.N. contributors:
0003  *
0004  * Antonio Quartulli
0005  */
0006 
0007 #include "bat_v_ogm.h"
0008 #include "main.h"
0009 
0010 #include <linux/atomic.h>
0011 #include <linux/byteorder/generic.h>
0012 #include <linux/container_of.h>
0013 #include <linux/errno.h>
0014 #include <linux/etherdevice.h>
0015 #include <linux/gfp.h>
0016 #include <linux/if_ether.h>
0017 #include <linux/jiffies.h>
0018 #include <linux/kref.h>
0019 #include <linux/list.h>
0020 #include <linux/lockdep.h>
0021 #include <linux/minmax.h>
0022 #include <linux/mutex.h>
0023 #include <linux/netdevice.h>
0024 #include <linux/prandom.h>
0025 #include <linux/random.h>
0026 #include <linux/rculist.h>
0027 #include <linux/rcupdate.h>
0028 #include <linux/skbuff.h>
0029 #include <linux/slab.h>
0030 #include <linux/spinlock.h>
0031 #include <linux/stddef.h>
0032 #include <linux/string.h>
0033 #include <linux/types.h>
0034 #include <linux/workqueue.h>
0035 #include <uapi/linux/batadv_packet.h>
0036 
0037 #include "bat_algo.h"
0038 #include "hard-interface.h"
0039 #include "hash.h"
0040 #include "log.h"
0041 #include "originator.h"
0042 #include "routing.h"
0043 #include "send.h"
0044 #include "translation-table.h"
0045 #include "tvlv.h"
0046 
0047 /**
0048  * batadv_v_ogm_orig_get() - retrieve and possibly create an originator node
0049  * @bat_priv: the bat priv with all the soft interface information
0050  * @addr: the address of the originator
0051  *
0052  * Return: the orig_node corresponding to the specified address. If such an
0053  * object does not exist, it is allocated here. In case of allocation failure
0054  * returns NULL.
0055  */
0056 struct batadv_orig_node *batadv_v_ogm_orig_get(struct batadv_priv *bat_priv,
0057                            const u8 *addr)
0058 {
0059     struct batadv_orig_node *orig_node;
0060     int hash_added;
0061 
0062     orig_node = batadv_orig_hash_find(bat_priv, addr);
0063     if (orig_node)
0064         return orig_node;
0065 
0066     orig_node = batadv_orig_node_new(bat_priv, addr);
0067     if (!orig_node)
0068         return NULL;
0069 
0070     kref_get(&orig_node->refcount);
0071     hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
0072                      batadv_choose_orig, orig_node,
0073                      &orig_node->hash_entry);
0074     if (hash_added != 0) {
0075         /* remove refcnt for newly created orig_node and hash entry */
0076         batadv_orig_node_put(orig_node);
0077         batadv_orig_node_put(orig_node);
0078         orig_node = NULL;
0079     }
0080 
0081     return orig_node;
0082 }
0083 
0084 /**
0085  * batadv_v_ogm_start_queue_timer() - restart the OGM aggregation timer
0086  * @hard_iface: the interface to use to send the OGM
0087  */
0088 static void batadv_v_ogm_start_queue_timer(struct batadv_hard_iface *hard_iface)
0089 {
0090     unsigned int msecs = BATADV_MAX_AGGREGATION_MS * 1000;
0091 
0092     /* msecs * [0.9, 1.1] */
0093     msecs += prandom_u32_max(msecs / 5) - (msecs / 10);
0094     queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.aggr_wq,
0095                msecs_to_jiffies(msecs / 1000));
0096 }
0097 
0098 /**
0099  * batadv_v_ogm_start_timer() - restart the OGM sending timer
0100  * @bat_priv: the bat priv with all the soft interface information
0101  */
0102 static void batadv_v_ogm_start_timer(struct batadv_priv *bat_priv)
0103 {
0104     unsigned long msecs;
0105     /* this function may be invoked in different contexts (ogm rescheduling
0106      * or hard_iface activation), but the work timer should not be reset
0107      */
0108     if (delayed_work_pending(&bat_priv->bat_v.ogm_wq))
0109         return;
0110 
0111     msecs = atomic_read(&bat_priv->orig_interval) - BATADV_JITTER;
0112     msecs += prandom_u32_max(2 * BATADV_JITTER);
0113     queue_delayed_work(batadv_event_workqueue, &bat_priv->bat_v.ogm_wq,
0114                msecs_to_jiffies(msecs));
0115 }
0116 
0117 /**
0118  * batadv_v_ogm_send_to_if() - send a batman ogm using a given interface
0119  * @skb: the OGM to send
0120  * @hard_iface: the interface to use to send the OGM
0121  */
0122 static void batadv_v_ogm_send_to_if(struct sk_buff *skb,
0123                     struct batadv_hard_iface *hard_iface)
0124 {
0125     struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
0126 
0127     if (hard_iface->if_status != BATADV_IF_ACTIVE)
0128         return;
0129 
0130     batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_TX);
0131     batadv_add_counter(bat_priv, BATADV_CNT_MGMT_TX_BYTES,
0132                skb->len + ETH_HLEN);
0133 
0134     batadv_send_broadcast_skb(skb, hard_iface);
0135 }
0136 
0137 /**
0138  * batadv_v_ogm_len() - OGMv2 packet length
0139  * @skb: the OGM to check
0140  *
0141  * Return: Length of the given OGMv2 packet, including tvlv length, excluding
0142  * ethernet header length.
0143  */
0144 static unsigned int batadv_v_ogm_len(struct sk_buff *skb)
0145 {
0146     struct batadv_ogm2_packet *ogm_packet;
0147 
0148     ogm_packet = (struct batadv_ogm2_packet *)skb->data;
0149     return BATADV_OGM2_HLEN + ntohs(ogm_packet->tvlv_len);
0150 }
0151 
0152 /**
0153  * batadv_v_ogm_queue_left() - check if given OGM still fits aggregation queue
0154  * @skb: the OGM to check
0155  * @hard_iface: the interface to use to send the OGM
0156  *
0157  * Caller needs to hold the hard_iface->bat_v.aggr_list.lock.
0158  *
0159  * Return: True, if the given OGMv2 packet still fits, false otherwise.
0160  */
0161 static bool batadv_v_ogm_queue_left(struct sk_buff *skb,
0162                     struct batadv_hard_iface *hard_iface)
0163 {
0164     unsigned int max = min_t(unsigned int, hard_iface->net_dev->mtu,
0165                  BATADV_MAX_AGGREGATION_BYTES);
0166     unsigned int ogm_len = batadv_v_ogm_len(skb);
0167 
0168     lockdep_assert_held(&hard_iface->bat_v.aggr_list.lock);
0169 
0170     return hard_iface->bat_v.aggr_len + ogm_len <= max;
0171 }
0172 
0173 /**
0174  * batadv_v_ogm_aggr_list_free - free all elements in an aggregation queue
0175  * @hard_iface: the interface holding the aggregation queue
0176  *
0177  * Empties the OGMv2 aggregation queue and frees all the skbs it contains.
0178  *
0179  * Caller needs to hold the hard_iface->bat_v.aggr_list.lock.
0180  */
0181 static void batadv_v_ogm_aggr_list_free(struct batadv_hard_iface *hard_iface)
0182 {
0183     lockdep_assert_held(&hard_iface->bat_v.aggr_list.lock);
0184 
0185     __skb_queue_purge(&hard_iface->bat_v.aggr_list);
0186     hard_iface->bat_v.aggr_len = 0;
0187 }
0188 
0189 /**
0190  * batadv_v_ogm_aggr_send() - flush & send aggregation queue
0191  * @hard_iface: the interface with the aggregation queue to flush
0192  *
0193  * Aggregates all OGMv2 packets currently in the aggregation queue into a
0194  * single OGMv2 packet and transmits this aggregate.
0195  *
0196  * The aggregation queue is empty after this call.
0197  *
0198  * Caller needs to hold the hard_iface->bat_v.aggr_list.lock.
0199  */
0200 static void batadv_v_ogm_aggr_send(struct batadv_hard_iface *hard_iface)
0201 {
0202     unsigned int aggr_len = hard_iface->bat_v.aggr_len;
0203     struct sk_buff *skb_aggr;
0204     unsigned int ogm_len;
0205     struct sk_buff *skb;
0206 
0207     lockdep_assert_held(&hard_iface->bat_v.aggr_list.lock);
0208 
0209     if (!aggr_len)
0210         return;
0211 
0212     skb_aggr = dev_alloc_skb(aggr_len + ETH_HLEN + NET_IP_ALIGN);
0213     if (!skb_aggr) {
0214         batadv_v_ogm_aggr_list_free(hard_iface);
0215         return;
0216     }
0217 
0218     skb_reserve(skb_aggr, ETH_HLEN + NET_IP_ALIGN);
0219     skb_reset_network_header(skb_aggr);
0220 
0221     while ((skb = __skb_dequeue(&hard_iface->bat_v.aggr_list))) {
0222         hard_iface->bat_v.aggr_len -= batadv_v_ogm_len(skb);
0223 
0224         ogm_len = batadv_v_ogm_len(skb);
0225         skb_put_data(skb_aggr, skb->data, ogm_len);
0226 
0227         consume_skb(skb);
0228     }
0229 
0230     batadv_v_ogm_send_to_if(skb_aggr, hard_iface);
0231 }
0232 
0233 /**
0234  * batadv_v_ogm_queue_on_if() - queue a batman ogm on a given interface
0235  * @skb: the OGM to queue
0236  * @hard_iface: the interface to queue the OGM on
0237  */
0238 static void batadv_v_ogm_queue_on_if(struct sk_buff *skb,
0239                      struct batadv_hard_iface *hard_iface)
0240 {
0241     struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
0242 
0243     if (!atomic_read(&bat_priv->aggregated_ogms)) {
0244         batadv_v_ogm_send_to_if(skb, hard_iface);
0245         return;
0246     }
0247 
0248     spin_lock_bh(&hard_iface->bat_v.aggr_list.lock);
0249     if (!batadv_v_ogm_queue_left(skb, hard_iface))
0250         batadv_v_ogm_aggr_send(hard_iface);
0251 
0252     hard_iface->bat_v.aggr_len += batadv_v_ogm_len(skb);
0253     __skb_queue_tail(&hard_iface->bat_v.aggr_list, skb);
0254     spin_unlock_bh(&hard_iface->bat_v.aggr_list.lock);
0255 }
0256 
0257 /**
0258  * batadv_v_ogm_send_softif() - periodic worker broadcasting the own OGM
0259  * @bat_priv: the bat priv with all the soft interface information
0260  */
0261 static void batadv_v_ogm_send_softif(struct batadv_priv *bat_priv)
0262 {
0263     struct batadv_hard_iface *hard_iface;
0264     struct batadv_ogm2_packet *ogm_packet;
0265     struct sk_buff *skb, *skb_tmp;
0266     unsigned char *ogm_buff;
0267     int ogm_buff_len;
0268     u16 tvlv_len = 0;
0269     int ret;
0270 
0271     lockdep_assert_held(&bat_priv->bat_v.ogm_buff_mutex);
0272 
0273     if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
0274         goto out;
0275 
0276     ogm_buff = bat_priv->bat_v.ogm_buff;
0277     ogm_buff_len = bat_priv->bat_v.ogm_buff_len;
0278     /* tt changes have to be committed before the tvlv data is
0279      * appended as it may alter the tt tvlv container
0280      */
0281     batadv_tt_local_commit_changes(bat_priv);
0282     tvlv_len = batadv_tvlv_container_ogm_append(bat_priv, &ogm_buff,
0283                             &ogm_buff_len,
0284                             BATADV_OGM2_HLEN);
0285 
0286     bat_priv->bat_v.ogm_buff = ogm_buff;
0287     bat_priv->bat_v.ogm_buff_len = ogm_buff_len;
0288 
0289     skb = netdev_alloc_skb_ip_align(NULL, ETH_HLEN + ogm_buff_len);
0290     if (!skb)
0291         goto reschedule;
0292 
0293     skb_reserve(skb, ETH_HLEN);
0294     skb_put_data(skb, ogm_buff, ogm_buff_len);
0295 
0296     ogm_packet = (struct batadv_ogm2_packet *)skb->data;
0297     ogm_packet->seqno = htonl(atomic_read(&bat_priv->bat_v.ogm_seqno));
0298     atomic_inc(&bat_priv->bat_v.ogm_seqno);
0299     ogm_packet->tvlv_len = htons(tvlv_len);
0300 
0301     /* broadcast on every interface */
0302     rcu_read_lock();
0303     list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
0304         if (hard_iface->soft_iface != bat_priv->soft_iface)
0305             continue;
0306 
0307         if (!kref_get_unless_zero(&hard_iface->refcount))
0308             continue;
0309 
0310         ret = batadv_hardif_no_broadcast(hard_iface, NULL, NULL);
0311         if (ret) {
0312             char *type;
0313 
0314             switch (ret) {
0315             case BATADV_HARDIF_BCAST_NORECIPIENT:
0316                 type = "no neighbor";
0317                 break;
0318             case BATADV_HARDIF_BCAST_DUPFWD:
0319                 type = "single neighbor is source";
0320                 break;
0321             case BATADV_HARDIF_BCAST_DUPORIG:
0322                 type = "single neighbor is originator";
0323                 break;
0324             default:
0325                 type = "unknown";
0326             }
0327 
0328             batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 from ourselves on %s suppressed: %s\n",
0329                    hard_iface->net_dev->name, type);
0330 
0331             batadv_hardif_put(hard_iface);
0332             continue;
0333         }
0334 
0335         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
0336                "Sending own OGM2 packet (originator %pM, seqno %u, throughput %u, TTL %d) on interface %s [%pM]\n",
0337                ogm_packet->orig, ntohl(ogm_packet->seqno),
0338                ntohl(ogm_packet->throughput), ogm_packet->ttl,
0339                hard_iface->net_dev->name,
0340                hard_iface->net_dev->dev_addr);
0341 
0342         /* this skb gets consumed by batadv_v_ogm_send_to_if() */
0343         skb_tmp = skb_clone(skb, GFP_ATOMIC);
0344         if (!skb_tmp) {
0345             batadv_hardif_put(hard_iface);
0346             break;
0347         }
0348 
0349         batadv_v_ogm_queue_on_if(skb_tmp, hard_iface);
0350         batadv_hardif_put(hard_iface);
0351     }
0352     rcu_read_unlock();
0353 
0354     consume_skb(skb);
0355 
0356 reschedule:
0357     batadv_v_ogm_start_timer(bat_priv);
0358 out:
0359     return;
0360 }
0361 
0362 /**
0363  * batadv_v_ogm_send() - periodic worker broadcasting the own OGM
0364  * @work: work queue item
0365  */
0366 static void batadv_v_ogm_send(struct work_struct *work)
0367 {
0368     struct batadv_priv_bat_v *bat_v;
0369     struct batadv_priv *bat_priv;
0370 
0371     bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
0372     bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
0373 
0374     mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
0375     batadv_v_ogm_send_softif(bat_priv);
0376     mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
0377 }
0378 
0379 /**
0380  * batadv_v_ogm_aggr_work() - OGM queue periodic task per interface
0381  * @work: work queue item
0382  *
0383  * Emits aggregated OGM messages in regular intervals.
0384  */
0385 void batadv_v_ogm_aggr_work(struct work_struct *work)
0386 {
0387     struct batadv_hard_iface_bat_v *batv;
0388     struct batadv_hard_iface *hard_iface;
0389 
0390     batv = container_of(work, struct batadv_hard_iface_bat_v, aggr_wq.work);
0391     hard_iface = container_of(batv, struct batadv_hard_iface, bat_v);
0392 
0393     spin_lock_bh(&hard_iface->bat_v.aggr_list.lock);
0394     batadv_v_ogm_aggr_send(hard_iface);
0395     spin_unlock_bh(&hard_iface->bat_v.aggr_list.lock);
0396 
0397     batadv_v_ogm_start_queue_timer(hard_iface);
0398 }
0399 
0400 /**
0401  * batadv_v_ogm_iface_enable() - prepare an interface for B.A.T.M.A.N. V
0402  * @hard_iface: the interface to prepare
0403  *
0404  * Takes care of scheduling its own OGM sending routine for this interface.
0405  *
0406  * Return: 0 on success or a negative error code otherwise
0407  */
0408 int batadv_v_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
0409 {
0410     struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
0411 
0412     batadv_v_ogm_start_queue_timer(hard_iface);
0413     batadv_v_ogm_start_timer(bat_priv);
0414 
0415     return 0;
0416 }
0417 
0418 /**
0419  * batadv_v_ogm_iface_disable() - release OGM interface private resources
0420  * @hard_iface: interface for which the resources have to be released
0421  */
0422 void batadv_v_ogm_iface_disable(struct batadv_hard_iface *hard_iface)
0423 {
0424     cancel_delayed_work_sync(&hard_iface->bat_v.aggr_wq);
0425 
0426     spin_lock_bh(&hard_iface->bat_v.aggr_list.lock);
0427     batadv_v_ogm_aggr_list_free(hard_iface);
0428     spin_unlock_bh(&hard_iface->bat_v.aggr_list.lock);
0429 }
0430 
0431 /**
0432  * batadv_v_ogm_primary_iface_set() - set a new primary interface
0433  * @primary_iface: the new primary interface
0434  */
0435 void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface)
0436 {
0437     struct batadv_priv *bat_priv = netdev_priv(primary_iface->soft_iface);
0438     struct batadv_ogm2_packet *ogm_packet;
0439 
0440     mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
0441     if (!bat_priv->bat_v.ogm_buff)
0442         goto unlock;
0443 
0444     ogm_packet = (struct batadv_ogm2_packet *)bat_priv->bat_v.ogm_buff;
0445     ether_addr_copy(ogm_packet->orig, primary_iface->net_dev->dev_addr);
0446 
0447 unlock:
0448     mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
0449 }
0450 
0451 /**
0452  * batadv_v_forward_penalty() - apply a penalty to the throughput metric
0453  *  forwarded with B.A.T.M.A.N. V OGMs
0454  * @bat_priv: the bat priv with all the soft interface information
0455  * @if_incoming: the interface where the OGM has been received
0456  * @if_outgoing: the interface where the OGM has to be forwarded to
0457  * @throughput: the current throughput
0458  *
0459  * Apply a penalty on the current throughput metric value based on the
0460  * characteristic of the interface where the OGM has been received.
0461  *
0462  * Initially the per hardif hop penalty is applied to the throughput. After
0463  * that the return value is then computed as follows:
0464  * - throughput * 50%          if the incoming and outgoing interface are the
0465  *                             same WiFi interface and the throughput is above
0466  *                             1MBit/s
0467  * - throughput                if the outgoing interface is the default
0468  *                             interface (i.e. this OGM is processed for the
0469  *                             internal table and not forwarded)
0470  * - throughput * node hop penalty  otherwise
0471  *
0472  * Return: the penalised throughput metric.
0473  */
0474 static u32 batadv_v_forward_penalty(struct batadv_priv *bat_priv,
0475                     struct batadv_hard_iface *if_incoming,
0476                     struct batadv_hard_iface *if_outgoing,
0477                     u32 throughput)
0478 {
0479     int if_hop_penalty = atomic_read(&if_incoming->hop_penalty);
0480     int hop_penalty = atomic_read(&bat_priv->hop_penalty);
0481     int hop_penalty_max = BATADV_TQ_MAX_VALUE;
0482 
0483     /* Apply per hardif hop penalty */
0484     throughput = throughput * (hop_penalty_max - if_hop_penalty) /
0485              hop_penalty_max;
0486 
0487     /* Don't apply hop penalty in default originator table. */
0488     if (if_outgoing == BATADV_IF_DEFAULT)
0489         return throughput;
0490 
0491     /* Forwarding on the same WiFi interface cuts the throughput in half
0492      * due to the store & forward characteristics of WIFI.
0493      * Very low throughput values are the exception.
0494      */
0495     if (throughput > 10 &&
0496         if_incoming == if_outgoing &&
0497         !(if_incoming->bat_v.flags & BATADV_FULL_DUPLEX))
0498         return throughput / 2;
0499 
0500     /* hop penalty of 255 equals 100% */
0501     return throughput * (hop_penalty_max - hop_penalty) / hop_penalty_max;
0502 }
0503 
0504 /**
0505  * batadv_v_ogm_forward() - check conditions and forward an OGM to the given
0506  *  outgoing interface
0507  * @bat_priv: the bat priv with all the soft interface information
0508  * @ogm_received: previously received OGM to be forwarded
0509  * @orig_node: the originator which has been updated
0510  * @neigh_node: the neigh_node through with the OGM has been received
0511  * @if_incoming: the interface on which this OGM was received on
0512  * @if_outgoing: the interface to which the OGM has to be forwarded to
0513  *
0514  * Forward an OGM to an interface after having altered the throughput metric and
0515  * the TTL value contained in it. The original OGM isn't modified.
0516  */
0517 static void batadv_v_ogm_forward(struct batadv_priv *bat_priv,
0518                  const struct batadv_ogm2_packet *ogm_received,
0519                  struct batadv_orig_node *orig_node,
0520                  struct batadv_neigh_node *neigh_node,
0521                  struct batadv_hard_iface *if_incoming,
0522                  struct batadv_hard_iface *if_outgoing)
0523 {
0524     struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
0525     struct batadv_orig_ifinfo *orig_ifinfo = NULL;
0526     struct batadv_neigh_node *router = NULL;
0527     struct batadv_ogm2_packet *ogm_forward;
0528     unsigned char *skb_buff;
0529     struct sk_buff *skb;
0530     size_t packet_len;
0531     u16 tvlv_len;
0532 
0533     /* only forward for specific interfaces, not for the default one. */
0534     if (if_outgoing == BATADV_IF_DEFAULT)
0535         goto out;
0536 
0537     orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
0538     if (!orig_ifinfo)
0539         goto out;
0540 
0541     /* acquire possibly updated router */
0542     router = batadv_orig_router_get(orig_node, if_outgoing);
0543 
0544     /* strict rule: forward packets coming from the best next hop only */
0545     if (neigh_node != router)
0546         goto out;
0547 
0548     /* don't forward the same seqno twice on one interface */
0549     if (orig_ifinfo->last_seqno_forwarded == ntohl(ogm_received->seqno))
0550         goto out;
0551 
0552     orig_ifinfo->last_seqno_forwarded = ntohl(ogm_received->seqno);
0553 
0554     if (ogm_received->ttl <= 1) {
0555         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "ttl exceeded\n");
0556         goto out;
0557     }
0558 
0559     neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
0560     if (!neigh_ifinfo)
0561         goto out;
0562 
0563     tvlv_len = ntohs(ogm_received->tvlv_len);
0564 
0565     packet_len = BATADV_OGM2_HLEN + tvlv_len;
0566     skb = netdev_alloc_skb_ip_align(if_outgoing->net_dev,
0567                     ETH_HLEN + packet_len);
0568     if (!skb)
0569         goto out;
0570 
0571     skb_reserve(skb, ETH_HLEN);
0572     skb_buff = skb_put_data(skb, ogm_received, packet_len);
0573 
0574     /* apply forward penalty */
0575     ogm_forward = (struct batadv_ogm2_packet *)skb_buff;
0576     ogm_forward->throughput = htonl(neigh_ifinfo->bat_v.throughput);
0577     ogm_forward->ttl--;
0578 
0579     batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
0580            "Forwarding OGM2 packet on %s: throughput %u, ttl %u, received via %s\n",
0581            if_outgoing->net_dev->name, ntohl(ogm_forward->throughput),
0582            ogm_forward->ttl, if_incoming->net_dev->name);
0583 
0584     batadv_v_ogm_queue_on_if(skb, if_outgoing);
0585 
0586 out:
0587     batadv_orig_ifinfo_put(orig_ifinfo);
0588     batadv_neigh_node_put(router);
0589     batadv_neigh_ifinfo_put(neigh_ifinfo);
0590 }
0591 
0592 /**
0593  * batadv_v_ogm_metric_update() - update route metric based on OGM
0594  * @bat_priv: the bat priv with all the soft interface information
0595  * @ogm2: OGM2 structure
0596  * @orig_node: Originator structure for which the OGM has been received
0597  * @neigh_node: the neigh_node through with the OGM has been received
0598  * @if_incoming: the interface where this packet was received
0599  * @if_outgoing: the interface for which the packet should be considered
0600  *
0601  * Return:
0602  *  1  if the OGM is new,
0603  *  0  if it is not new but valid,
0604  *  <0 on error (e.g. old OGM)
0605  */
0606 static int batadv_v_ogm_metric_update(struct batadv_priv *bat_priv,
0607                       const struct batadv_ogm2_packet *ogm2,
0608                       struct batadv_orig_node *orig_node,
0609                       struct batadv_neigh_node *neigh_node,
0610                       struct batadv_hard_iface *if_incoming,
0611                       struct batadv_hard_iface *if_outgoing)
0612 {
0613     struct batadv_orig_ifinfo *orig_ifinfo;
0614     struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
0615     bool protection_started = false;
0616     int ret = -EINVAL;
0617     u32 path_throughput;
0618     s32 seq_diff;
0619 
0620     orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
0621     if (!orig_ifinfo)
0622         goto out;
0623 
0624     seq_diff = ntohl(ogm2->seqno) - orig_ifinfo->last_real_seqno;
0625 
0626     if (!hlist_empty(&orig_node->neigh_list) &&
0627         batadv_window_protected(bat_priv, seq_diff,
0628                     BATADV_OGM_MAX_AGE,
0629                     &orig_ifinfo->batman_seqno_reset,
0630                     &protection_started)) {
0631         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
0632                "Drop packet: packet within window protection time from %pM\n",
0633                ogm2->orig);
0634         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
0635                "Last reset: %ld, %ld\n",
0636                orig_ifinfo->batman_seqno_reset, jiffies);
0637         goto out;
0638     }
0639 
0640     /* drop packets with old seqnos, however accept the first packet after
0641      * a host has been rebooted.
0642      */
0643     if (seq_diff < 0 && !protection_started)
0644         goto out;
0645 
0646     neigh_node->last_seen = jiffies;
0647 
0648     orig_node->last_seen = jiffies;
0649 
0650     orig_ifinfo->last_real_seqno = ntohl(ogm2->seqno);
0651     orig_ifinfo->last_ttl = ogm2->ttl;
0652 
0653     neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
0654     if (!neigh_ifinfo)
0655         goto out;
0656 
0657     path_throughput = batadv_v_forward_penalty(bat_priv, if_incoming,
0658                            if_outgoing,
0659                            ntohl(ogm2->throughput));
0660     neigh_ifinfo->bat_v.throughput = path_throughput;
0661     neigh_ifinfo->bat_v.last_seqno = ntohl(ogm2->seqno);
0662     neigh_ifinfo->last_ttl = ogm2->ttl;
0663 
0664     if (seq_diff > 0 || protection_started)
0665         ret = 1;
0666     else
0667         ret = 0;
0668 out:
0669     batadv_orig_ifinfo_put(orig_ifinfo);
0670     batadv_neigh_ifinfo_put(neigh_ifinfo);
0671 
0672     return ret;
0673 }
0674 
0675 /**
0676  * batadv_v_ogm_route_update() - update routes based on OGM
0677  * @bat_priv: the bat priv with all the soft interface information
0678  * @ethhdr: the Ethernet header of the OGM2
0679  * @ogm2: OGM2 structure
0680  * @orig_node: Originator structure for which the OGM has been received
0681  * @neigh_node: the neigh_node through with the OGM has been received
0682  * @if_incoming: the interface where this packet was received
0683  * @if_outgoing: the interface for which the packet should be considered
0684  *
0685  * Return: true if the packet should be forwarded, false otherwise
0686  */
0687 static bool batadv_v_ogm_route_update(struct batadv_priv *bat_priv,
0688                       const struct ethhdr *ethhdr,
0689                       const struct batadv_ogm2_packet *ogm2,
0690                       struct batadv_orig_node *orig_node,
0691                       struct batadv_neigh_node *neigh_node,
0692                       struct batadv_hard_iface *if_incoming,
0693                       struct batadv_hard_iface *if_outgoing)
0694 {
0695     struct batadv_neigh_node *router = NULL;
0696     struct batadv_orig_node *orig_neigh_node;
0697     struct batadv_neigh_node *orig_neigh_router = NULL;
0698     struct batadv_neigh_ifinfo *router_ifinfo = NULL, *neigh_ifinfo = NULL;
0699     u32 router_throughput, neigh_throughput;
0700     u32 router_last_seqno;
0701     u32 neigh_last_seqno;
0702     s32 neigh_seq_diff;
0703     bool forward = false;
0704 
0705     orig_neigh_node = batadv_v_ogm_orig_get(bat_priv, ethhdr->h_source);
0706     if (!orig_neigh_node)
0707         goto out;
0708 
0709     orig_neigh_router = batadv_orig_router_get(orig_neigh_node,
0710                            if_outgoing);
0711 
0712     /* drop packet if sender is not a direct neighbor and if we
0713      * don't route towards it
0714      */
0715     router = batadv_orig_router_get(orig_node, if_outgoing);
0716     if (router && router->orig_node != orig_node && !orig_neigh_router) {
0717         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
0718                "Drop packet: OGM via unknown neighbor!\n");
0719         goto out;
0720     }
0721 
0722     /* Mark the OGM to be considered for forwarding, and update routes
0723      * if needed.
0724      */
0725     forward = true;
0726 
0727     batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
0728            "Searching and updating originator entry of received packet\n");
0729 
0730     /* if this neighbor already is our next hop there is nothing
0731      * to change
0732      */
0733     if (router == neigh_node)
0734         goto out;
0735 
0736     /* don't consider neighbours with worse throughput.
0737      * also switch route if this seqno is BATADV_V_MAX_ORIGDIFF newer than
0738      * the last received seqno from our best next hop.
0739      */
0740     if (router) {
0741         router_ifinfo = batadv_neigh_ifinfo_get(router, if_outgoing);
0742         neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
0743 
0744         /* if these are not allocated, something is wrong. */
0745         if (!router_ifinfo || !neigh_ifinfo)
0746             goto out;
0747 
0748         neigh_last_seqno = neigh_ifinfo->bat_v.last_seqno;
0749         router_last_seqno = router_ifinfo->bat_v.last_seqno;
0750         neigh_seq_diff = neigh_last_seqno - router_last_seqno;
0751         router_throughput = router_ifinfo->bat_v.throughput;
0752         neigh_throughput = neigh_ifinfo->bat_v.throughput;
0753 
0754         if (neigh_seq_diff < BATADV_OGM_MAX_ORIGDIFF &&
0755             router_throughput >= neigh_throughput)
0756             goto out;
0757     }
0758 
0759     batadv_update_route(bat_priv, orig_node, if_outgoing, neigh_node);
0760 out:
0761     batadv_neigh_node_put(router);
0762     batadv_neigh_node_put(orig_neigh_router);
0763     batadv_orig_node_put(orig_neigh_node);
0764     batadv_neigh_ifinfo_put(router_ifinfo);
0765     batadv_neigh_ifinfo_put(neigh_ifinfo);
0766 
0767     return forward;
0768 }
0769 
0770 /**
0771  * batadv_v_ogm_process_per_outif() - process a batman v OGM for an outgoing if
0772  * @bat_priv: the bat priv with all the soft interface information
0773  * @ethhdr: the Ethernet header of the OGM2
0774  * @ogm2: OGM2 structure
0775  * @orig_node: Originator structure for which the OGM has been received
0776  * @neigh_node: the neigh_node through with the OGM has been received
0777  * @if_incoming: the interface where this packet was received
0778  * @if_outgoing: the interface for which the packet should be considered
0779  */
0780 static void
0781 batadv_v_ogm_process_per_outif(struct batadv_priv *bat_priv,
0782                    const struct ethhdr *ethhdr,
0783                    const struct batadv_ogm2_packet *ogm2,
0784                    struct batadv_orig_node *orig_node,
0785                    struct batadv_neigh_node *neigh_node,
0786                    struct batadv_hard_iface *if_incoming,
0787                    struct batadv_hard_iface *if_outgoing)
0788 {
0789     int seqno_age;
0790     bool forward;
0791 
0792     /* first, update the metric with according sanity checks */
0793     seqno_age = batadv_v_ogm_metric_update(bat_priv, ogm2, orig_node,
0794                            neigh_node, if_incoming,
0795                            if_outgoing);
0796 
0797     /* outdated sequence numbers are to be discarded */
0798     if (seqno_age < 0)
0799         return;
0800 
0801     /* only unknown & newer OGMs contain TVLVs we are interested in */
0802     if (seqno_age > 0 && if_outgoing == BATADV_IF_DEFAULT)
0803         batadv_tvlv_containers_process(bat_priv, true, orig_node,
0804                            NULL, NULL,
0805                            (unsigned char *)(ogm2 + 1),
0806                            ntohs(ogm2->tvlv_len));
0807 
0808     /* if the metric update went through, update routes if needed */
0809     forward = batadv_v_ogm_route_update(bat_priv, ethhdr, ogm2, orig_node,
0810                         neigh_node, if_incoming,
0811                         if_outgoing);
0812 
0813     /* if the routes have been processed correctly, check and forward */
0814     if (forward)
0815         batadv_v_ogm_forward(bat_priv, ogm2, orig_node, neigh_node,
0816                      if_incoming, if_outgoing);
0817 }
0818 
0819 /**
0820  * batadv_v_ogm_aggr_packet() - checks if there is another OGM aggregated
0821  * @buff_pos: current position in the skb
0822  * @packet_len: total length of the skb
0823  * @ogm2_packet: potential OGM2 in buffer
0824  *
0825  * Return: true if there is enough space for another OGM, false otherwise.
0826  */
0827 static bool
0828 batadv_v_ogm_aggr_packet(int buff_pos, int packet_len,
0829              const struct batadv_ogm2_packet *ogm2_packet)
0830 {
0831     int next_buff_pos = 0;
0832 
0833     /* check if there is enough space for the header */
0834     next_buff_pos += buff_pos + sizeof(*ogm2_packet);
0835     if (next_buff_pos > packet_len)
0836         return false;
0837 
0838     /* check if there is enough space for the optional TVLV */
0839     next_buff_pos += ntohs(ogm2_packet->tvlv_len);
0840 
0841     return (next_buff_pos <= packet_len) &&
0842            (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
0843 }
0844 
0845 /**
0846  * batadv_v_ogm_process() - process an incoming batman v OGM
0847  * @skb: the skb containing the OGM
0848  * @ogm_offset: offset to the OGM which should be processed (for aggregates)
0849  * @if_incoming: the interface where this packet was received
0850  */
0851 static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset,
0852                  struct batadv_hard_iface *if_incoming)
0853 {
0854     struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
0855     struct ethhdr *ethhdr;
0856     struct batadv_orig_node *orig_node = NULL;
0857     struct batadv_hardif_neigh_node *hardif_neigh = NULL;
0858     struct batadv_neigh_node *neigh_node = NULL;
0859     struct batadv_hard_iface *hard_iface;
0860     struct batadv_ogm2_packet *ogm_packet;
0861     u32 ogm_throughput, link_throughput, path_throughput;
0862     int ret;
0863 
0864     ethhdr = eth_hdr(skb);
0865     ogm_packet = (struct batadv_ogm2_packet *)(skb->data + ogm_offset);
0866 
0867     ogm_throughput = ntohl(ogm_packet->throughput);
0868 
0869     batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
0870            "Received OGM2 packet via NB: %pM, IF: %s [%pM] (from OG: %pM, seqno %u, throughput %u, TTL %u, V %u, tvlv_len %u)\n",
0871            ethhdr->h_source, if_incoming->net_dev->name,
0872            if_incoming->net_dev->dev_addr, ogm_packet->orig,
0873            ntohl(ogm_packet->seqno), ogm_throughput, ogm_packet->ttl,
0874            ogm_packet->version, ntohs(ogm_packet->tvlv_len));
0875 
0876     if (batadv_is_my_mac(bat_priv, ogm_packet->orig)) {
0877         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
0878                "Drop packet: originator packet from ourself\n");
0879         return;
0880     }
0881 
0882     /* If the throughput metric is 0, immediately drop the packet. No need
0883      * to create orig_node / neigh_node for an unusable route.
0884      */
0885     if (ogm_throughput == 0) {
0886         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
0887                "Drop packet: originator packet with throughput metric of 0\n");
0888         return;
0889     }
0890 
0891     /* require ELP packets be to received from this neighbor first */
0892     hardif_neigh = batadv_hardif_neigh_get(if_incoming, ethhdr->h_source);
0893     if (!hardif_neigh) {
0894         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
0895                "Drop packet: OGM via unknown neighbor!\n");
0896         goto out;
0897     }
0898 
0899     orig_node = batadv_v_ogm_orig_get(bat_priv, ogm_packet->orig);
0900     if (!orig_node)
0901         goto out;
0902 
0903     neigh_node = batadv_neigh_node_get_or_create(orig_node, if_incoming,
0904                              ethhdr->h_source);
0905     if (!neigh_node)
0906         goto out;
0907 
0908     /* Update the received throughput metric to match the link
0909      * characteristic:
0910      *  - If this OGM traveled one hop so far (emitted by single hop
0911      *    neighbor) the path throughput metric equals the link throughput.
0912      *  - For OGMs traversing more than hop the path throughput metric is
0913      *    the smaller of the path throughput and the link throughput.
0914      */
0915     link_throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
0916     path_throughput = min_t(u32, link_throughput, ogm_throughput);
0917     ogm_packet->throughput = htonl(path_throughput);
0918 
0919     batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet, orig_node,
0920                        neigh_node, if_incoming,
0921                        BATADV_IF_DEFAULT);
0922 
0923     rcu_read_lock();
0924     list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
0925         if (hard_iface->if_status != BATADV_IF_ACTIVE)
0926             continue;
0927 
0928         if (hard_iface->soft_iface != bat_priv->soft_iface)
0929             continue;
0930 
0931         if (!kref_get_unless_zero(&hard_iface->refcount))
0932             continue;
0933 
0934         ret = batadv_hardif_no_broadcast(hard_iface,
0935                          ogm_packet->orig,
0936                          hardif_neigh->orig);
0937 
0938         if (ret) {
0939             char *type;
0940 
0941             switch (ret) {
0942             case BATADV_HARDIF_BCAST_NORECIPIENT:
0943                 type = "no neighbor";
0944                 break;
0945             case BATADV_HARDIF_BCAST_DUPFWD:
0946                 type = "single neighbor is source";
0947                 break;
0948             case BATADV_HARDIF_BCAST_DUPORIG:
0949                 type = "single neighbor is originator";
0950                 break;
0951             default:
0952                 type = "unknown";
0953             }
0954 
0955             batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 packet from %pM on %s suppressed: %s\n",
0956                    ogm_packet->orig, hard_iface->net_dev->name,
0957                    type);
0958 
0959             batadv_hardif_put(hard_iface);
0960             continue;
0961         }
0962 
0963         batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet,
0964                            orig_node, neigh_node,
0965                            if_incoming, hard_iface);
0966 
0967         batadv_hardif_put(hard_iface);
0968     }
0969     rcu_read_unlock();
0970 out:
0971     batadv_orig_node_put(orig_node);
0972     batadv_neigh_node_put(neigh_node);
0973     batadv_hardif_neigh_put(hardif_neigh);
0974 }
0975 
0976 /**
0977  * batadv_v_ogm_packet_recv() - OGM2 receiving handler
0978  * @skb: the received OGM
0979  * @if_incoming: the interface where this OGM has been received
0980  *
0981  * Return: NET_RX_SUCCESS and consume the skb on success or returns NET_RX_DROP
0982  * (without freeing the skb) on failure
0983  */
0984 int batadv_v_ogm_packet_recv(struct sk_buff *skb,
0985                  struct batadv_hard_iface *if_incoming)
0986 {
0987     struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
0988     struct batadv_ogm2_packet *ogm_packet;
0989     struct ethhdr *ethhdr = eth_hdr(skb);
0990     int ogm_offset;
0991     u8 *packet_pos;
0992     int ret = NET_RX_DROP;
0993 
0994     /* did we receive a OGM2 packet on an interface that does not have
0995      * B.A.T.M.A.N. V enabled ?
0996      */
0997     if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
0998         goto free_skb;
0999 
1000     if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN))
1001         goto free_skb;
1002 
1003     if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1004         goto free_skb;
1005 
1006     batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
1007     batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
1008                skb->len + ETH_HLEN);
1009 
1010     ogm_offset = 0;
1011     ogm_packet = (struct batadv_ogm2_packet *)skb->data;
1012 
1013     while (batadv_v_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
1014                     ogm_packet)) {
1015         batadv_v_ogm_process(skb, ogm_offset, if_incoming);
1016 
1017         ogm_offset += BATADV_OGM2_HLEN;
1018         ogm_offset += ntohs(ogm_packet->tvlv_len);
1019 
1020         packet_pos = skb->data + ogm_offset;
1021         ogm_packet = (struct batadv_ogm2_packet *)packet_pos;
1022     }
1023 
1024     ret = NET_RX_SUCCESS;
1025 
1026 free_skb:
1027     if (ret == NET_RX_SUCCESS)
1028         consume_skb(skb);
1029     else
1030         kfree_skb(skb);
1031 
1032     return ret;
1033 }
1034 
1035 /**
1036  * batadv_v_ogm_init() - initialise the OGM2 engine
1037  * @bat_priv: the bat priv with all the soft interface information
1038  *
1039  * Return: 0 on success or a negative error code in case of failure
1040  */
1041 int batadv_v_ogm_init(struct batadv_priv *bat_priv)
1042 {
1043     struct batadv_ogm2_packet *ogm_packet;
1044     unsigned char *ogm_buff;
1045     u32 random_seqno;
1046 
1047     bat_priv->bat_v.ogm_buff_len = BATADV_OGM2_HLEN;
1048     ogm_buff = kzalloc(bat_priv->bat_v.ogm_buff_len, GFP_ATOMIC);
1049     if (!ogm_buff)
1050         return -ENOMEM;
1051 
1052     bat_priv->bat_v.ogm_buff = ogm_buff;
1053     ogm_packet = (struct batadv_ogm2_packet *)ogm_buff;
1054     ogm_packet->packet_type = BATADV_OGM2;
1055     ogm_packet->version = BATADV_COMPAT_VERSION;
1056     ogm_packet->ttl = BATADV_TTL;
1057     ogm_packet->flags = BATADV_NO_FLAGS;
1058     ogm_packet->throughput = htonl(BATADV_THROUGHPUT_MAX_VALUE);
1059 
1060     /* randomize initial seqno to avoid collision */
1061     get_random_bytes(&random_seqno, sizeof(random_seqno));
1062     atomic_set(&bat_priv->bat_v.ogm_seqno, random_seqno);
1063     INIT_DELAYED_WORK(&bat_priv->bat_v.ogm_wq, batadv_v_ogm_send);
1064 
1065     mutex_init(&bat_priv->bat_v.ogm_buff_mutex);
1066 
1067     return 0;
1068 }
1069 
1070 /**
1071  * batadv_v_ogm_free() - free OGM private resources
1072  * @bat_priv: the bat priv with all the soft interface information
1073  */
1074 void batadv_v_ogm_free(struct batadv_priv *bat_priv)
1075 {
1076     cancel_delayed_work_sync(&bat_priv->bat_v.ogm_wq);
1077 
1078     mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
1079 
1080     kfree(bat_priv->bat_v.ogm_buff);
1081     bat_priv->bat_v.ogm_buff = NULL;
1082     bat_priv->bat_v.ogm_buff_len = 0;
1083 
1084     mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
1085 }
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