// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) B.A.T.M.A.N. contributors:
*
* Edo Monticelli, Antonio Quartulli
*/
#include "tp_meter.h"
#include "main.h"
#include <linux/atomic.h>
#include <linux/build_bug.h>
#include <linux/byteorder/generic.h>
#include <linux/cache.h>
#include <linux/compiler.h>
#include <linux/container_of.h>
#include <linux/err.h>
#include <linux/etherdevice.h>
#include <linux/gfp.h>
#include <linux/if_ether.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/kref.h>
#include <linux/kthread.h>
#include <linux/limits.h>
#include <linux/list.h>
#include <linux/minmax.h>
#include <linux/netdevice.h>
#include <linux/param.h>
#include <linux/printk.h>
#include <linux/random.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/sched.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <uapi/linux/batadv_packet.h>
#include <uapi/linux/batman_adv.h>
#include "hard-interface.h"
#include "log.h"
#include "netlink.h"
#include "originator.h"
#include "send.h"
/**
* BATADV_TP_DEF_TEST_LENGTH - Default test length if not specified by the user
* in milliseconds
*/
#define BATADV_TP_DEF_TEST_LENGTH 10000
/**
* BATADV_TP_AWND - Advertised window by the receiver (in bytes)
*/
#define BATADV_TP_AWND 0x20000000
/**
* BATADV_TP_RECV_TIMEOUT - Receiver activity timeout. If the receiver does not
* get anything for such amount of milliseconds, the connection is killed
*/
#define BATADV_TP_RECV_TIMEOUT 1000
/**
* BATADV_TP_MAX_RTO - Maximum sender timeout. If the sender RTO gets beyond
* such amount of milliseconds, the receiver is considered unreachable and the
* connection is killed
*/
#define BATADV_TP_MAX_RTO 30000
/**
* BATADV_TP_FIRST_SEQ - First seqno of each session. The number is rather high
* in order to immediately trigger a wrap around (test purposes)
*/
#define BATADV_TP_FIRST_SEQ ((u32)-1 - 2000)
/**
* BATADV_TP_PLEN - length of the payload (data after the batadv_unicast header)
* to simulate
*/
#define BATADV_TP_PLEN (BATADV_TP_PACKET_LEN - ETH_HLEN - \
sizeof(struct batadv_unicast_packet))
static u8 batadv_tp_prerandom[4096] __read_mostly;
/**
* batadv_tp_session_cookie() - generate session cookie based on session ids
* @session: TP session identifier
* @icmp_uid: icmp pseudo uid of the tp session
*
* Return: 32 bit tp_meter session cookie
*/
static u32 batadv_tp_session_cookie(const u8 session[2], u8 icmp_uid)
{
u32 cookie;
cookie = icmp_uid << 16;
cookie |= session[0] << 8;
cookie |= session[1];
return cookie;
}
/**
* batadv_tp_cwnd() - compute the new cwnd size
* @base: base cwnd size value
* @increment: the value to add to base to get the new size
* @min: minimum cwnd value (usually MSS)
*
* Return the new cwnd size and ensure it does not exceed the Advertised
* Receiver Window size. It is wrapped around safely.
* For details refer to Section 3.1 of RFC5681
*
* Return: new congestion window size in bytes
*/
static u32 batadv_tp_cwnd(u32 base, u32 increment, u32 min)
{
u32 new_size = base + increment;
/* check for wrap-around */
if (new_size < base)
new_size = (u32)ULONG_MAX;
new_size = min_t(u32, new_size, BATADV_TP_AWND);
return max_t(u32, new_size, min);
}
/**
* batadv_tp_update_cwnd() - update the Congestion Windows
* @tp_vars: the private data of the current TP meter session
* @mss: maximum segment size of transmission
*
* 1) if the session is in Slow Start, the CWND has to be increased by 1
* MSS every unique received ACK
* 2) if the session is in Congestion Avoidance, the CWND has to be
* increased by MSS * MSS / CWND for every unique received ACK
*/
static void batadv_tp_update_cwnd(struct batadv_tp_vars *tp_vars, u32 mss)
{
spin_lock_bh(&tp_vars->cwnd_lock);
/* slow start... */
if (tp_vars->cwnd <= tp_vars->ss_threshold) {
tp_vars->dec_cwnd = 0;
tp_vars->cwnd = batadv_tp_cwnd(tp_vars->cwnd, mss, mss);
spin_unlock_bh(&tp_vars->cwnd_lock);
return;
}
/* increment CWND at least of 1 (section 3.1 of RFC5681) */
tp_vars->dec_cwnd += max_t(u32, 1U << 3,
((mss * mss) << 6) / (tp_vars->cwnd << 3));
if (tp_vars->dec_cwnd < (mss << 3)) {
spin_unlock_bh(&tp_vars->cwnd_lock);
return;
}
tp_vars->cwnd = batadv_tp_cwnd(tp_vars->cwnd, mss, mss);
tp_vars->dec_cwnd = 0;
spin_unlock_bh(&tp_vars->cwnd_lock);
}
/**
* batadv_tp_update_rto() - calculate new retransmission timeout
* @tp_vars: the private data of the current TP meter session
* @new_rtt: new roundtrip time in msec
*/
static void batadv_tp_update_rto(struct batadv_tp_vars *tp_vars,
u32 new_rtt)
{
long m = new_rtt;
/* RTT update
* Details in Section 2.2 and 2.3 of RFC6298
*
* It's tricky to understand. Don't lose hair please.
* Inspired by tcp_rtt_estimator() tcp_input.c
*/
if (tp_vars->srtt != 0) {
m -= (tp_vars->srtt >> 3); /* m is now error in rtt est */
tp_vars->srtt += m; /* rtt = 7/8 srtt + 1/8 new */
if (m < 0)
m = -m;
m -= (tp_vars->rttvar >> 2);
tp_vars->rttvar += m; /* mdev ~= 3/4 rttvar + 1/4 new */
} else {
/* first measure getting in */
tp_vars->srtt = m << 3; /* take the measured time to be srtt */
tp_vars->rttvar = m << 1; /* new_rtt / 2 */
}
/* rto = srtt + 4 * rttvar.
* rttvar is scaled by 4, therefore doesn't need to be multiplied
*/
tp_vars->rto = (tp_vars->srtt >> 3) + tp_vars->rttvar;
}
/**
* batadv_tp_batctl_notify() - send client status result to client
* @reason: reason for tp meter session stop
* @dst: destination of tp_meter session
* @bat_priv: the bat priv with all the soft interface information
* @start_time: start of transmission in jiffies
* @total_sent: bytes acked to the receiver
* @cookie: cookie of tp_meter session
*/
static void batadv_tp_batctl_notify(enum batadv_tp_meter_reason reason,
const u8 *dst, struct batadv_priv *bat_priv,
unsigned long start_time, u64 total_sent,
u32 cookie)
{
u32 test_time;
u8 result;
u32 total_bytes;
if (!batadv_tp_is_error(reason)) {
result = BATADV_TP_REASON_COMPLETE;
test_time = jiffies_to_msecs(jiffies - start_time);
total_bytes = total_sent;
} else {
result = reason;
test_time = 0;
total_bytes = 0;
}
batadv_netlink_tpmeter_notify(bat_priv, dst, result, test_time,
total_bytes, cookie);
}
/**
* batadv_tp_batctl_error_notify() - send client error result to client
* @reason: reason for tp meter session stop
* @dst: destination of tp_meter session
* @bat_priv: the bat priv with all the soft interface information
* @cookie: cookie of tp_meter session
*/
static void batadv_tp_batctl_error_notify(enum batadv_tp_meter_reason reason,
const u8 *dst,
struct batadv_priv *bat_priv,
u32 cookie)
{
batadv_tp_batctl_notify(reason, dst, bat_priv, 0, 0, cookie);
}
/**
* batadv_tp_list_find() - find a tp_vars object in the global list
* @bat_priv: the bat priv with all the soft interface information
* @dst: the other endpoint MAC address to look for
*
* Look for a tp_vars object matching dst as end_point and return it after
* having increment the refcounter. Return NULL is not found
*
* Return: matching tp_vars or NULL when no tp_vars with @dst was found
*/
static struct batadv_tp_vars *batadv_tp_list_find(struct batadv_priv *bat_priv,
const u8 *dst)
{
struct batadv_tp_vars *pos, *tp_vars = NULL;
rcu_read_lock();
hlist_for_each_entry_rcu(pos, &bat_priv->tp_list, list) {
if (!batadv_compare_eth(pos->other_end, dst))
continue;
/* most of the time this function is invoked during the normal
* process..it makes sens to pay more when the session is
* finished and to speed the process up during the measurement
*/
if (unlikely(!kref_get_unless_zero(&pos->refcount)))
continue;
tp_vars = pos;
break;
}
rcu_read_unlock();
return tp_vars;
}
/**
* batadv_tp_list_find_session() - find tp_vars session object in the global
* list
* @bat_priv: the bat priv with all the soft interface information
* @dst: the other endpoint MAC address to look for
* @session: session identifier
*
* Look for a tp_vars object matching dst as end_point, session as tp meter
* session and return it after having increment the refcounter. Return NULL
* is not found
*
* Return: matching tp_vars or NULL when no tp_vars was found
*/
static struct batadv_tp_vars *
batadv_tp_list_find_session(struct batadv_priv *bat_priv, const u8 *dst,
const u8 *session)
{
struct batadv_tp_vars *pos, *tp_vars = NULL;
rcu_read_lock();
hlist_for_each_entry_rcu(pos, &bat_priv->tp_list, list) {
if (!batadv_compare_eth(pos->other_end, dst))
continue;
if (memcmp(pos->session, session, sizeof(pos->session)) != 0)
continue;
/* most of the time this function is invoked during the normal
* process..it makes sense to pay more when the session is
* finished and to speed the process up during the measurement
*/
if (unlikely(!kref_get_unless_zero(&pos->refcount)))
continue;
tp_vars = pos;
break;
}
rcu_read_unlock();
return tp_vars;
}
/**
* batadv_tp_vars_release() - release batadv_tp_vars from lists and queue for
* free after rcu grace period
* @ref: kref pointer of the batadv_tp_vars
*/
static void batadv_tp_vars_release(struct kref *ref)
{
struct batadv_tp_vars *tp_vars;
struct batadv_tp_unacked *un, *safe;
tp_vars = container_of(ref, struct batadv_tp_vars, refcount);
/* lock should not be needed because this object is now out of any
* context!
*/
spin_lock_bh(&tp_vars->unacked_lock);
list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
list_del(&un->list);
kfree(un);
}
spin_unlock_bh(&tp_vars->unacked_lock);
kfree_rcu(tp_vars, rcu);
}
/**
* batadv_tp_vars_put() - decrement the batadv_tp_vars refcounter and possibly
* release it
* @tp_vars: the private data of the current TP meter session to be free'd
*/
static void batadv_tp_vars_put(struct batadv_tp_vars *tp_vars)
{
if (!tp_vars)
return;
kref_put(&tp_vars->refcount, batadv_tp_vars_release);
}
/**
* batadv_tp_sender_cleanup() - cleanup sender data and drop and timer
* @bat_priv: the bat priv with all the soft interface information
* @tp_vars: the private data of the current TP meter session to cleanup
*/
static void batadv_tp_sender_cleanup(struct batadv_priv *bat_priv,
struct batadv_tp_vars *tp_vars)
{
cancel_delayed_work(&tp_vars->finish_work);
spin_lock_bh(&tp_vars->bat_priv->tp_list_lock);
hlist_del_rcu(&tp_vars->list);
spin_unlock_bh(&tp_vars->bat_priv->tp_list_lock);
/* drop list reference */
batadv_tp_vars_put(tp_vars);
atomic_dec(&tp_vars->bat_priv->tp_num);
/* kill the timer and remove its reference */
del_timer_sync(&tp_vars->timer);
/* the worker might have rearmed itself therefore we kill it again. Note
* that if the worker should run again before invoking the following
* del_timer(), it would not re-arm itself once again because the status
* is OFF now
*/
del_timer(&tp_vars->timer);
batadv_tp_vars_put(tp_vars);
}
/**
* batadv_tp_sender_end() - print info about ended session and inform client
* @bat_priv: the bat priv with all the soft interface information
* @tp_vars: the private data of the current TP meter session
*/
static void batadv_tp_sender_end(struct batadv_priv *bat_priv,
struct batadv_tp_vars *tp_vars)
{
u32 session_cookie;
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Test towards %pM finished..shutting down (reason=%d)\n",
tp_vars->other_end, tp_vars->reason);
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Last timing stats: SRTT=%ums RTTVAR=%ums RTO=%ums\n",
tp_vars->srtt >> 3, tp_vars->rttvar >> 2, tp_vars->rto);
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Final values: cwnd=%u ss_threshold=%u\n",
tp_vars->cwnd, tp_vars->ss_threshold);
session_cookie = batadv_tp_session_cookie(tp_vars->session,
tp_vars->icmp_uid);
batadv_tp_batctl_notify(tp_vars->reason,
tp_vars->other_end,
bat_priv,
tp_vars->start_time,
atomic64_read(&tp_vars->tot_sent),
session_cookie);
}
/**
* batadv_tp_sender_shutdown() - let sender thread/timer stop gracefully
* @tp_vars: the private data of the current TP meter session
* @reason: reason for tp meter session stop
*/
static void batadv_tp_sender_shutdown(struct batadv_tp_vars *tp_vars,
enum batadv_tp_meter_reason reason)
{
if (!atomic_dec_and_test(&tp_vars->sending))
return;
tp_vars->reason = reason;
}
/**
* batadv_tp_sender_finish() - stop sender session after test_length was reached
* @work: delayed work reference of the related tp_vars
*/
static void batadv_tp_sender_finish(struct work_struct *work)
{
struct delayed_work *delayed_work;
struct batadv_tp_vars *tp_vars;
delayed_work = to_delayed_work(work);
tp_vars = container_of(delayed_work, struct batadv_tp_vars,
finish_work);
batadv_tp_sender_shutdown(tp_vars, BATADV_TP_REASON_COMPLETE);
}
/**
* batadv_tp_reset_sender_timer() - reschedule the sender timer
* @tp_vars: the private TP meter data for this session
*
* Reschedule the timer using tp_vars->rto as delay
*/
static void batadv_tp_reset_sender_timer(struct batadv_tp_vars *tp_vars)
{
/* most of the time this function is invoked while normal packet
* reception...
*/
if (unlikely(atomic_read(&tp_vars->sending) == 0))
/* timer ref will be dropped in batadv_tp_sender_cleanup */
return;
mod_timer(&tp_vars->timer, jiffies + msecs_to_jiffies(tp_vars->rto));
}
/**
* batadv_tp_sender_timeout() - timer that fires in case of packet loss
* @t: address to timer_list inside tp_vars
*
* If fired it means that there was packet loss.
* Switch to Slow Start, set the ss_threshold to half of the current cwnd and
* reset the cwnd to 3*MSS
*/
static void batadv_tp_sender_timeout(struct timer_list *t)
{
struct batadv_tp_vars *tp_vars = from_timer(tp_vars, t, timer);
struct batadv_priv *bat_priv = tp_vars->bat_priv;
if (atomic_read(&tp_vars->sending) == 0)
return;
/* if the user waited long enough...shutdown the test */
if (unlikely(tp_vars->rto >= BATADV_TP_MAX_RTO)) {
batadv_tp_sender_shutdown(tp_vars,
BATADV_TP_REASON_DST_UNREACHABLE);
return;
}
/* RTO exponential backoff
* Details in Section 5.5 of RFC6298
*/
tp_vars->rto <<= 1;
spin_lock_bh(&tp_vars->cwnd_lock);
tp_vars->ss_threshold = tp_vars->cwnd >> 1;
if (tp_vars->ss_threshold < BATADV_TP_PLEN * 2)
tp_vars->ss_threshold = BATADV_TP_PLEN * 2;
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Meter: RTO fired during test towards %pM! cwnd=%u new ss_thr=%u, resetting last_sent to %u\n",
tp_vars->other_end, tp_vars->cwnd, tp_vars->ss_threshold,
atomic_read(&tp_vars->last_acked));
tp_vars->cwnd = BATADV_TP_PLEN * 3;
spin_unlock_bh(&tp_vars->cwnd_lock);
/* resend the non-ACKed packets.. */
tp_vars->last_sent = atomic_read(&tp_vars->last_acked);
wake_up(&tp_vars->more_bytes);
batadv_tp_reset_sender_timer(tp_vars);
}
/**
* batadv_tp_fill_prerandom() - Fill buffer with prefetched random bytes
* @tp_vars: the private TP meter data for this session
* @buf: Buffer to fill with bytes
* @nbytes: amount of pseudorandom bytes
*/
static void batadv_tp_fill_prerandom(struct batadv_tp_vars *tp_vars,
u8 *buf, size_t nbytes)
{
u32 local_offset;
size_t bytes_inbuf;
size_t to_copy;
size_t pos = 0;
spin_lock_bh(&tp_vars->prerandom_lock);
local_offset = tp_vars->prerandom_offset;
tp_vars->prerandom_offset += nbytes;
tp_vars->prerandom_offset %= sizeof(batadv_tp_prerandom);
spin_unlock_bh(&tp_vars->prerandom_lock);
while (nbytes) {
local_offset %= sizeof(batadv_tp_prerandom);
bytes_inbuf = sizeof(batadv_tp_prerandom) - local_offset;
to_copy = min(nbytes, bytes_inbuf);
memcpy(&buf[pos], &batadv_tp_prerandom[local_offset], to_copy);
pos += to_copy;
nbytes -= to_copy;
local_offset = 0;
}
}
/**
* batadv_tp_send_msg() - send a single message
* @tp_vars: the private TP meter data for this session
* @src: source mac address
* @orig_node: the originator of the destination
* @seqno: sequence number of this packet
* @len: length of the entire packet
* @session: session identifier
* @uid: local ICMP "socket" index
* @timestamp: timestamp in jiffies which is replied in ack
*
* Create and send a single TP Meter message.
*
* Return: 0 on success, BATADV_TP_REASON_DST_UNREACHABLE if the destination is
* not reachable, BATADV_TP_REASON_MEMORY_ERROR if the packet couldn't be
* allocated
*/
static int batadv_tp_send_msg(struct batadv_tp_vars *tp_vars, const u8 *src,
struct batadv_orig_node *orig_node,
u32 seqno, size_t len, const u8 *session,
int uid, u32 timestamp)
{
struct batadv_icmp_tp_packet *icmp;
struct sk_buff *skb;
int r;
u8 *data;
size_t data_len;
skb = netdev_alloc_skb_ip_align(NULL, len + ETH_HLEN);
if (unlikely(!skb))
return BATADV_TP_REASON_MEMORY_ERROR;
skb_reserve(skb, ETH_HLEN);
icmp = skb_put(skb, sizeof(*icmp));
/* fill the icmp header */
ether_addr_copy(icmp->dst, orig_node->orig);
ether_addr_copy(icmp->orig, src);
icmp->version = BATADV_COMPAT_VERSION;
icmp->packet_type = BATADV_ICMP;
icmp->ttl = BATADV_TTL;
icmp->msg_type = BATADV_TP;
icmp->uid = uid;
icmp->subtype = BATADV_TP_MSG;
memcpy(icmp->session, session, sizeof(icmp->session));
icmp->seqno = htonl(seqno);
icmp->timestamp = htonl(timestamp);
data_len = len - sizeof(*icmp);
data = skb_put(skb, data_len);
batadv_tp_fill_prerandom(tp_vars, data, data_len);
r = batadv_send_skb_to_orig(skb, orig_node, NULL);
if (r == NET_XMIT_SUCCESS)
return 0;
return BATADV_TP_REASON_CANT_SEND;
}
/**
* batadv_tp_recv_ack() - ACK receiving function
* @bat_priv: the bat priv with all the soft interface information
* @skb: the buffer containing the received packet
*
* Process a received TP ACK packet
*/
static void batadv_tp_recv_ack(struct batadv_priv *bat_priv,
const struct sk_buff *skb)
{
struct batadv_hard_iface *primary_if = NULL;
struct batadv_orig_node *orig_node = NULL;
const struct batadv_icmp_tp_packet *icmp;
struct batadv_tp_vars *tp_vars;
const unsigned char *dev_addr;
size_t packet_len, mss;
u32 rtt, recv_ack, cwnd;
packet_len = BATADV_TP_PLEN;
mss = BATADV_TP_PLEN;
packet_len += sizeof(struct batadv_unicast_packet);
icmp = (struct batadv_icmp_tp_packet *)skb->data;
/* find the tp_vars */
tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
icmp->session);
if (unlikely(!tp_vars))
return;
if (unlikely(atomic_read(&tp_vars->sending) == 0))
goto out;
/* old ACK? silently drop it.. */
if (batadv_seq_before(ntohl(icmp->seqno),
(u32)atomic_read(&tp_vars->last_acked)))
goto out;
primary_if = batadv_primary_if_get_selected(bat_priv);
if (unlikely(!primary_if))
goto out;
orig_node = batadv_orig_hash_find(bat_priv, icmp->orig);
if (unlikely(!orig_node))
goto out;
/* update RTO with the new sampled RTT, if any */
rtt = jiffies_to_msecs(jiffies) - ntohl(icmp->timestamp);
if (icmp->timestamp && rtt)
batadv_tp_update_rto(tp_vars, rtt);
/* ACK for new data... reset the timer */
batadv_tp_reset_sender_timer(tp_vars);
recv_ack = ntohl(icmp->seqno);
/* check if this ACK is a duplicate */
if (atomic_read(&tp_vars->last_acked) == recv_ack) {
atomic_inc(&tp_vars->dup_acks);
if (atomic_read(&tp_vars->dup_acks) != 3)
goto out;
if (recv_ack >= tp_vars->recover)
goto out;
/* if this is the third duplicate ACK do Fast Retransmit */
batadv_tp_send_msg(tp_vars, primary_if->net_dev->dev_addr,
orig_node, recv_ack, packet_len,
icmp->session, icmp->uid,
jiffies_to_msecs(jiffies));
spin_lock_bh(&tp_vars->cwnd_lock);
/* Fast Recovery */
tp_vars->fast_recovery = true;
/* Set recover to the last outstanding seqno when Fast Recovery
* is entered. RFC6582, Section 3.2, step 1
*/
tp_vars->recover = tp_vars->last_sent;
tp_vars->ss_threshold = tp_vars->cwnd >> 1;
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Meter: Fast Recovery, (cur cwnd=%u) ss_thr=%u last_sent=%u recv_ack=%u\n",
tp_vars->cwnd, tp_vars->ss_threshold,
tp_vars->last_sent, recv_ack);
tp_vars->cwnd = batadv_tp_cwnd(tp_vars->ss_threshold, 3 * mss,
mss);
tp_vars->dec_cwnd = 0;
tp_vars->last_sent = recv_ack;
spin_unlock_bh(&tp_vars->cwnd_lock);
} else {
/* count the acked data */
atomic64_add(recv_ack - atomic_read(&tp_vars->last_acked),
&tp_vars->tot_sent);
/* reset the duplicate ACKs counter */
atomic_set(&tp_vars->dup_acks, 0);
if (tp_vars->fast_recovery) {
/* partial ACK */
if (batadv_seq_before(recv_ack, tp_vars->recover)) {
/* this is another hole in the window. React
* immediately as specified by NewReno (see
* Section 3.2 of RFC6582 for details)
*/
dev_addr = primary_if->net_dev->dev_addr;
batadv_tp_send_msg(tp_vars, dev_addr,
orig_node, recv_ack,
packet_len, icmp->session,
icmp->uid,
jiffies_to_msecs(jiffies));
tp_vars->cwnd = batadv_tp_cwnd(tp_vars->cwnd,
mss, mss);
} else {
tp_vars->fast_recovery = false;
/* set cwnd to the value of ss_threshold at the
* moment that Fast Recovery was entered.
* RFC6582, Section 3.2, step 3
*/
cwnd = batadv_tp_cwnd(tp_vars->ss_threshold, 0,
mss);
tp_vars->cwnd = cwnd;
}
goto move_twnd;
}
if (recv_ack - atomic_read(&tp_vars->last_acked) >= mss)
batadv_tp_update_cwnd(tp_vars, mss);
move_twnd:
/* move the Transmit Window */
atomic_set(&tp_vars->last_acked, recv_ack);
}
wake_up(&tp_vars->more_bytes);
out:
batadv_hardif_put(primary_if);
batadv_orig_node_put(orig_node);
batadv_tp_vars_put(tp_vars);
}
/**
* batadv_tp_avail() - check if congestion window is not full
* @tp_vars: the private data of the current TP meter session
* @payload_len: size of the payload of a single message
*
* Return: true when congestion window is not full, false otherwise
*/
static bool batadv_tp_avail(struct batadv_tp_vars *tp_vars,
size_t payload_len)
{
u32 win_left, win_limit;
win_limit = atomic_read(&tp_vars->last_acked) + tp_vars->cwnd;
win_left = win_limit - tp_vars->last_sent;
return win_left >= payload_len;
}
/**
* batadv_tp_wait_available() - wait until congestion window becomes free or
* timeout is reached
* @tp_vars: the private data of the current TP meter session
* @plen: size of the payload of a single message
*
* Return: 0 if the condition evaluated to false after the timeout elapsed,
* 1 if the condition evaluated to true after the timeout elapsed, the
* remaining jiffies (at least 1) if the condition evaluated to true before
* the timeout elapsed, or -ERESTARTSYS if it was interrupted by a signal.
*/
static int batadv_tp_wait_available(struct batadv_tp_vars *tp_vars, size_t plen)
{
int ret;
ret = wait_event_interruptible_timeout(tp_vars->more_bytes,
batadv_tp_avail(tp_vars, plen),
HZ / 10);
return ret;
}
/**
* batadv_tp_send() - main sending thread of a tp meter session
* @arg: address of the related tp_vars
*
* Return: nothing, this function never returns
*/
static int batadv_tp_send(void *arg)
{
struct batadv_tp_vars *tp_vars = arg;
struct batadv_priv *bat_priv = tp_vars->bat_priv;
struct batadv_hard_iface *primary_if = NULL;
struct batadv_orig_node *orig_node = NULL;
size_t payload_len, packet_len;
int err = 0;
if (unlikely(tp_vars->role != BATADV_TP_SENDER)) {
err = BATADV_TP_REASON_DST_UNREACHABLE;
tp_vars->reason = err;
goto out;
}
orig_node = batadv_orig_hash_find(bat_priv, tp_vars->other_end);
if (unlikely(!orig_node)) {
err = BATADV_TP_REASON_DST_UNREACHABLE;
tp_vars->reason = err;
goto out;
}
primary_if = batadv_primary_if_get_selected(bat_priv);
if (unlikely(!primary_if)) {
err = BATADV_TP_REASON_DST_UNREACHABLE;
tp_vars->reason = err;
goto out;
}
/* assume that all the hard_interfaces have a correctly
* configured MTU, so use the soft_iface MTU as MSS.
* This might not be true and in that case the fragmentation
* should be used.
* Now, try to send the packet as it is
*/
payload_len = BATADV_TP_PLEN;
BUILD_BUG_ON(sizeof(struct batadv_icmp_tp_packet) > BATADV_TP_PLEN);
batadv_tp_reset_sender_timer(tp_vars);
/* queue the worker in charge of terminating the test */
queue_delayed_work(batadv_event_workqueue, &tp_vars->finish_work,
msecs_to_jiffies(tp_vars->test_length));
while (atomic_read(&tp_vars->sending) != 0) {
if (unlikely(!batadv_tp_avail(tp_vars, payload_len))) {
batadv_tp_wait_available(tp_vars, payload_len);
continue;
}
/* to emulate normal unicast traffic, add to the payload len
* the size of the unicast header
*/
packet_len = payload_len + sizeof(struct batadv_unicast_packet);
err = batadv_tp_send_msg(tp_vars, primary_if->net_dev->dev_addr,
orig_node, tp_vars->last_sent,
packet_len,
tp_vars->session, tp_vars->icmp_uid,
jiffies_to_msecs(jiffies));
/* something went wrong during the preparation/transmission */
if (unlikely(err && err != BATADV_TP_REASON_CANT_SEND)) {
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Meter: %s() cannot send packets (%d)\n",
__func__, err);
/* ensure nobody else tries to stop the thread now */
if (atomic_dec_and_test(&tp_vars->sending))
tp_vars->reason = err;
break;
}
/* right-shift the TWND */
if (!err)
tp_vars->last_sent += payload_len;
cond_resched();
}
out:
batadv_hardif_put(primary_if);
batadv_orig_node_put(orig_node);
batadv_tp_sender_end(bat_priv, tp_vars);
batadv_tp_sender_cleanup(bat_priv, tp_vars);
batadv_tp_vars_put(tp_vars);
return 0;
}
/**
* batadv_tp_start_kthread() - start new thread which manages the tp meter
* sender
* @tp_vars: the private data of the current TP meter session
*/
static void batadv_tp_start_kthread(struct batadv_tp_vars *tp_vars)
{
struct task_struct *kthread;
struct batadv_priv *bat_priv = tp_vars->bat_priv;
u32 session_cookie;
kref_get(&tp_vars->refcount);
kthread = kthread_create(batadv_tp_send, tp_vars, "kbatadv_tp_meter");
if (IS_ERR(kthread)) {
session_cookie = batadv_tp_session_cookie(tp_vars->session,
tp_vars->icmp_uid);
pr_err("batadv: cannot create tp meter kthread\n");
batadv_tp_batctl_error_notify(BATADV_TP_REASON_MEMORY_ERROR,
tp_vars->other_end,
bat_priv, session_cookie);
/* drop reserved reference for kthread */
batadv_tp_vars_put(tp_vars);
/* cleanup of failed tp meter variables */
batadv_tp_sender_cleanup(bat_priv, tp_vars);
return;
}
wake_up_process(kthread);
}
/**
* batadv_tp_start() - start a new tp meter session
* @bat_priv: the bat priv with all the soft interface information
* @dst: the receiver MAC address
* @test_length: test length in milliseconds
* @cookie: session cookie
*/
void batadv_tp_start(struct batadv_priv *bat_priv, const u8 *dst,
u32 test_length, u32 *cookie)
{
struct batadv_tp_vars *tp_vars;
u8 session_id[2];
u8 icmp_uid;
u32 session_cookie;
get_random_bytes(session_id, sizeof(session_id));
get_random_bytes(&icmp_uid, 1);
session_cookie = batadv_tp_session_cookie(session_id, icmp_uid);
*cookie = session_cookie;
/* look for an already existing test towards this node */
spin_lock_bh(&bat_priv->tp_list_lock);
tp_vars = batadv_tp_list_find(bat_priv, dst);
if (tp_vars) {
spin_unlock_bh(&bat_priv->tp_list_lock);
batadv_tp_vars_put(tp_vars);
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Meter: test to or from the same node already ongoing, aborting\n");
batadv_tp_batctl_error_notify(BATADV_TP_REASON_ALREADY_ONGOING,
dst, bat_priv, session_cookie);
return;
}
if (!atomic_add_unless(&bat_priv->tp_num, 1, BATADV_TP_MAX_NUM)) {
spin_unlock_bh(&bat_priv->tp_list_lock);
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Meter: too many ongoing sessions, aborting (SEND)\n");
batadv_tp_batctl_error_notify(BATADV_TP_REASON_TOO_MANY, dst,
bat_priv, session_cookie);
return;
}
tp_vars = kmalloc(sizeof(*tp_vars), GFP_ATOMIC);
if (!tp_vars) {
spin_unlock_bh(&bat_priv->tp_list_lock);
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Meter: %s cannot allocate list elements\n",
__func__);
batadv_tp_batctl_error_notify(BATADV_TP_REASON_MEMORY_ERROR,
dst, bat_priv, session_cookie);
return;
}
/* initialize tp_vars */
ether_addr_copy(tp_vars->other_end, dst);
kref_init(&tp_vars->refcount);
tp_vars->role = BATADV_TP_SENDER;
atomic_set(&tp_vars->sending, 1);
memcpy(tp_vars->session, session_id, sizeof(session_id));
tp_vars->icmp_uid = icmp_uid;
tp_vars->last_sent = BATADV_TP_FIRST_SEQ;
atomic_set(&tp_vars->last_acked, BATADV_TP_FIRST_SEQ);
tp_vars->fast_recovery = false;
tp_vars->recover = BATADV_TP_FIRST_SEQ;
/* initialise the CWND to 3*MSS (Section 3.1 in RFC5681).
* For batman-adv the MSS is the size of the payload received by the
* soft_interface, hence its MTU
*/
tp_vars->cwnd = BATADV_TP_PLEN * 3;
/* at the beginning initialise the SS threshold to the biggest possible
* window size, hence the AWND size
*/
tp_vars->ss_threshold = BATADV_TP_AWND;
/* RTO initial value is 3 seconds.
* Details in Section 2.1 of RFC6298
*/
tp_vars->rto = 1000;
tp_vars->srtt = 0;
tp_vars->rttvar = 0;
atomic64_set(&tp_vars->tot_sent, 0);
kref_get(&tp_vars->refcount);
timer_setup(&tp_vars->timer, batadv_tp_sender_timeout, 0);
tp_vars->bat_priv = bat_priv;
tp_vars->start_time = jiffies;
init_waitqueue_head(&tp_vars->more_bytes);
spin_lock_init(&tp_vars->unacked_lock);
INIT_LIST_HEAD(&tp_vars->unacked_list);
spin_lock_init(&tp_vars->cwnd_lock);
tp_vars->prerandom_offset = 0;
spin_lock_init(&tp_vars->prerandom_lock);
kref_get(&tp_vars->refcount);
hlist_add_head_rcu(&tp_vars->list, &bat_priv->tp_list);
spin_unlock_bh(&bat_priv->tp_list_lock);
tp_vars->test_length = test_length;
if (!tp_vars->test_length)
tp_vars->test_length = BATADV_TP_DEF_TEST_LENGTH;
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Meter: starting throughput meter towards %pM (length=%ums)\n",
dst, test_length);
/* init work item for finished tp tests */
INIT_DELAYED_WORK(&tp_vars->finish_work, batadv_tp_sender_finish);
/* start tp kthread. This way the write() call issued from userspace can
* happily return and avoid to block
*/
batadv_tp_start_kthread(tp_vars);
/* don't return reference to new tp_vars */
batadv_tp_vars_put(tp_vars);
}
/**
* batadv_tp_stop() - stop currently running tp meter session
* @bat_priv: the bat priv with all the soft interface information
* @dst: the receiver MAC address
* @return_value: reason for tp meter session stop
*/
void batadv_tp_stop(struct batadv_priv *bat_priv, const u8 *dst,
u8 return_value)
{
struct batadv_orig_node *orig_node;
struct batadv_tp_vars *tp_vars;
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Meter: stopping test towards %pM\n", dst);
orig_node = batadv_orig_hash_find(bat_priv, dst);
if (!orig_node)
return;
tp_vars = batadv_tp_list_find(bat_priv, orig_node->orig);
if (!tp_vars) {
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Meter: trying to interrupt an already over connection\n");
goto out;
}
batadv_tp_sender_shutdown(tp_vars, return_value);
batadv_tp_vars_put(tp_vars);
out:
batadv_orig_node_put(orig_node);
}
/**
* batadv_tp_reset_receiver_timer() - reset the receiver shutdown timer
* @tp_vars: the private data of the current TP meter session
*
* start the receiver shutdown timer or reset it if already started
*/
static void batadv_tp_reset_receiver_timer(struct batadv_tp_vars *tp_vars)
{
mod_timer(&tp_vars->timer,
jiffies + msecs_to_jiffies(BATADV_TP_RECV_TIMEOUT));
}
/**
* batadv_tp_receiver_shutdown() - stop a tp meter receiver when timeout is
* reached without received ack
* @t: address to timer_list inside tp_vars
*/
static void batadv_tp_receiver_shutdown(struct timer_list *t)
{
struct batadv_tp_vars *tp_vars = from_timer(tp_vars, t, timer);
struct batadv_tp_unacked *un, *safe;
struct batadv_priv *bat_priv;
bat_priv = tp_vars->bat_priv;
/* if there is recent activity rearm the timer */
if (!batadv_has_timed_out(tp_vars->last_recv_time,
BATADV_TP_RECV_TIMEOUT)) {
/* reset the receiver shutdown timer */
batadv_tp_reset_receiver_timer(tp_vars);
return;
}
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Shutting down for inactivity (more than %dms) from %pM\n",
BATADV_TP_RECV_TIMEOUT, tp_vars->other_end);
spin_lock_bh(&tp_vars->bat_priv->tp_list_lock);
hlist_del_rcu(&tp_vars->list);
spin_unlock_bh(&tp_vars->bat_priv->tp_list_lock);
/* drop list reference */
batadv_tp_vars_put(tp_vars);
atomic_dec(&bat_priv->tp_num);
spin_lock_bh(&tp_vars->unacked_lock);
list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
list_del(&un->list);
kfree(un);
}
spin_unlock_bh(&tp_vars->unacked_lock);
/* drop reference of timer */
batadv_tp_vars_put(tp_vars);
}
/**
* batadv_tp_send_ack() - send an ACK packet
* @bat_priv: the bat priv with all the soft interface information
* @dst: the mac address of the destination originator
* @seq: the sequence number to ACK
* @timestamp: the timestamp to echo back in the ACK
* @session: session identifier
* @socket_index: local ICMP socket identifier
*
* Return: 0 on success, a positive integer representing the reason of the
* failure otherwise
*/
static int batadv_tp_send_ack(struct batadv_priv *bat_priv, const u8 *dst,
u32 seq, __be32 timestamp, const u8 *session,
int socket_index)
{
struct batadv_hard_iface *primary_if = NULL;
struct batadv_orig_node *orig_node;
struct batadv_icmp_tp_packet *icmp;
struct sk_buff *skb;
int r, ret;
orig_node = batadv_orig_hash_find(bat_priv, dst);
if (unlikely(!orig_node)) {
ret = BATADV_TP_REASON_DST_UNREACHABLE;
goto out;
}
primary_if = batadv_primary_if_get_selected(bat_priv);
if (unlikely(!primary_if)) {
ret = BATADV_TP_REASON_DST_UNREACHABLE;
goto out;
}
skb = netdev_alloc_skb_ip_align(NULL, sizeof(*icmp) + ETH_HLEN);
if (unlikely(!skb)) {
ret = BATADV_TP_REASON_MEMORY_ERROR;
goto out;
}
skb_reserve(skb, ETH_HLEN);
icmp = skb_put(skb, sizeof(*icmp));
icmp->packet_type = BATADV_ICMP;
icmp->version = BATADV_COMPAT_VERSION;
icmp->ttl = BATADV_TTL;
icmp->msg_type = BATADV_TP;
ether_addr_copy(icmp->dst, orig_node->orig);
ether_addr_copy(icmp->orig, primary_if->net_dev->dev_addr);
icmp->uid = socket_index;
icmp->subtype = BATADV_TP_ACK;
memcpy(icmp->session, session, sizeof(icmp->session));
icmp->seqno = htonl(seq);
icmp->timestamp = timestamp;
/* send the ack */
r = batadv_send_skb_to_orig(skb, orig_node, NULL);
if (unlikely(r < 0) || r == NET_XMIT_DROP) {
ret = BATADV_TP_REASON_DST_UNREACHABLE;
goto out;
}
ret = 0;
out:
batadv_orig_node_put(orig_node);
batadv_hardif_put(primary_if);
return ret;
}
/**
* batadv_tp_handle_out_of_order() - store an out of order packet
* @tp_vars: the private data of the current TP meter session
* @skb: the buffer containing the received packet
*
* Store the out of order packet in the unacked list for late processing. This
* packets are kept in this list so that they can be ACKed at once as soon as
* all the previous packets have been received
*
* Return: true if the packed has been successfully processed, false otherwise
*/
static bool batadv_tp_handle_out_of_order(struct batadv_tp_vars *tp_vars,
const struct sk_buff *skb)
{
const struct batadv_icmp_tp_packet *icmp;
struct batadv_tp_unacked *un, *new;
u32 payload_len;
bool added = false;
new = kmalloc(sizeof(*new), GFP_ATOMIC);
if (unlikely(!new))
return false;
icmp = (struct batadv_icmp_tp_packet *)skb->data;
new->seqno = ntohl(icmp->seqno);
payload_len = skb->len - sizeof(struct batadv_unicast_packet);
new->len = payload_len;
spin_lock_bh(&tp_vars->unacked_lock);
/* if the list is empty immediately attach this new object */
if (list_empty(&tp_vars->unacked_list)) {
list_add(&new->list, &tp_vars->unacked_list);
goto out;
}
/* otherwise loop over the list and either drop the packet because this
* is a duplicate or store it at the right position.
*
* The iteration is done in the reverse way because it is likely that
* the last received packet (the one being processed now) has a bigger
* seqno than all the others already stored.
*/
list_for_each_entry_reverse(un, &tp_vars->unacked_list, list) {
/* check for duplicates */
if (new->seqno == un->seqno) {
if (new->len > un->len)
un->len = new->len;
kfree(new);
added = true;
break;
}
/* look for the right position */
if (batadv_seq_before(new->seqno, un->seqno))
continue;
/* as soon as an entry having a bigger seqno is found, the new
* one is attached _after_ it. In this way the list is kept in
* ascending order
*/
list_add_tail(&new->list, &un->list);
added = true;
break;
}
/* received packet with smallest seqno out of order; add it to front */
if (!added)
list_add(&new->list, &tp_vars->unacked_list);
out:
spin_unlock_bh(&tp_vars->unacked_lock);
return true;
}
/**
* batadv_tp_ack_unordered() - update number received bytes in current stream
* without gaps
* @tp_vars: the private data of the current TP meter session
*/
static void batadv_tp_ack_unordered(struct batadv_tp_vars *tp_vars)
{
struct batadv_tp_unacked *un, *safe;
u32 to_ack;
/* go through the unacked packet list and possibly ACK them as
* well
*/
spin_lock_bh(&tp_vars->unacked_lock);
list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
/* the list is ordered, therefore it is possible to stop as soon
* there is a gap between the last acked seqno and the seqno of
* the packet under inspection
*/
if (batadv_seq_before(tp_vars->last_recv, un->seqno))
break;
to_ack = un->seqno + un->len - tp_vars->last_recv;
if (batadv_seq_before(tp_vars->last_recv, un->seqno + un->len))
tp_vars->last_recv += to_ack;
list_del(&un->list);
kfree(un);
}
spin_unlock_bh(&tp_vars->unacked_lock);
}
/**
* batadv_tp_init_recv() - return matching or create new receiver tp_vars
* @bat_priv: the bat priv with all the soft interface information
* @icmp: received icmp tp msg
*
* Return: corresponding tp_vars or NULL on errors
*/
static struct batadv_tp_vars *
batadv_tp_init_recv(struct batadv_priv *bat_priv,
const struct batadv_icmp_tp_packet *icmp)
{
struct batadv_tp_vars *tp_vars;
spin_lock_bh(&bat_priv->tp_list_lock);
tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
icmp->session);
if (tp_vars)
goto out_unlock;
if (!atomic_add_unless(&bat_priv->tp_num, 1, BATADV_TP_MAX_NUM)) {
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Meter: too many ongoing sessions, aborting (RECV)\n");
goto out_unlock;
}
tp_vars = kmalloc(sizeof(*tp_vars), GFP_ATOMIC);
if (!tp_vars)
goto out_unlock;
ether_addr_copy(tp_vars->other_end, icmp->orig);
tp_vars->role = BATADV_TP_RECEIVER;
memcpy(tp_vars->session, icmp->session, sizeof(tp_vars->session));
tp_vars->last_recv = BATADV_TP_FIRST_SEQ;
tp_vars->bat_priv = bat_priv;
kref_init(&tp_vars->refcount);
spin_lock_init(&tp_vars->unacked_lock);
INIT_LIST_HEAD(&tp_vars->unacked_list);
kref_get(&tp_vars->refcount);
hlist_add_head_rcu(&tp_vars->list, &bat_priv->tp_list);
kref_get(&tp_vars->refcount);
timer_setup(&tp_vars->timer, batadv_tp_receiver_shutdown, 0);
batadv_tp_reset_receiver_timer(tp_vars);
out_unlock:
spin_unlock_bh(&bat_priv->tp_list_lock);
return tp_vars;
}
/**
* batadv_tp_recv_msg() - process a single data message
* @bat_priv: the bat priv with all the soft interface information
* @skb: the buffer containing the received packet
*
* Process a received TP MSG packet
*/
static void batadv_tp_recv_msg(struct batadv_priv *bat_priv,
const struct sk_buff *skb)
{
const struct batadv_icmp_tp_packet *icmp;
struct batadv_tp_vars *tp_vars;
size_t packet_size;
u32 seqno;
icmp = (struct batadv_icmp_tp_packet *)skb->data;
seqno = ntohl(icmp->seqno);
/* check if this is the first seqno. This means that if the
* first packet is lost, the tp meter does not work anymore!
*/
if (seqno == BATADV_TP_FIRST_SEQ) {
tp_vars = batadv_tp_init_recv(bat_priv, icmp);
if (!tp_vars) {
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Meter: seqno != BATADV_TP_FIRST_SEQ cannot initiate connection\n");
goto out;
}
} else {
tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
icmp->session);
if (!tp_vars) {
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Unexpected packet from %pM!\n",
icmp->orig);
goto out;
}
}
if (unlikely(tp_vars->role != BATADV_TP_RECEIVER)) {
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Meter: dropping packet: not expected (role=%u)\n",
tp_vars->role);
goto out;
}
tp_vars->last_recv_time = jiffies;
/* if the packet is a duplicate, it may be the case that an ACK has been
* lost. Resend the ACK
*/
if (batadv_seq_before(seqno, tp_vars->last_recv))
goto send_ack;
/* if the packet is out of order enqueue it */
if (ntohl(icmp->seqno) != tp_vars->last_recv) {
/* exit immediately (and do not send any ACK) if the packet has
* not been enqueued correctly
*/
if (!batadv_tp_handle_out_of_order(tp_vars, skb))
goto out;
/* send a duplicate ACK */
goto send_ack;
}
/* if everything was fine count the ACKed bytes */
packet_size = skb->len - sizeof(struct batadv_unicast_packet);
tp_vars->last_recv += packet_size;
/* check if this ordered message filled a gap.... */
batadv_tp_ack_unordered(tp_vars);
send_ack:
/* send the ACK. If the received packet was out of order, the ACK that
* is going to be sent is a duplicate (the sender will count them and
* possibly enter Fast Retransmit as soon as it has reached 3)
*/
batadv_tp_send_ack(bat_priv, icmp->orig, tp_vars->last_recv,
icmp->timestamp, icmp->session, icmp->uid);
out:
batadv_tp_vars_put(tp_vars);
}
/**
* batadv_tp_meter_recv() - main TP Meter receiving function
* @bat_priv: the bat priv with all the soft interface information
* @skb: the buffer containing the received packet
*/
void batadv_tp_meter_recv(struct batadv_priv *bat_priv, struct sk_buff *skb)
{
struct batadv_icmp_tp_packet *icmp;
icmp = (struct batadv_icmp_tp_packet *)skb->data;
switch (icmp->subtype) {
case BATADV_TP_MSG:
batadv_tp_recv_msg(bat_priv, skb);
break;
case BATADV_TP_ACK:
batadv_tp_recv_ack(bat_priv, skb);
break;
default:
batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
"Received unknown TP Metric packet type %u\n",
icmp->subtype);
}
consume_skb(skb);
}
/**
* batadv_tp_meter_init() - initialize global tp_meter structures
*/
void __init batadv_tp_meter_init(void)
{
get_random_bytes(batadv_tp_prerandom, sizeof(batadv_tp_prerandom));
}
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