diff options
Diffstat (limited to 'net/batman-adv/tp_meter.c')
| -rw-r--r-- | net/batman-adv/tp_meter.c | 1505 |
1 files changed, 1505 insertions, 0 deletions
diff --git a/net/batman-adv/tp_meter.c b/net/batman-adv/tp_meter.c new file mode 100644 index 000000000..11520de96 --- /dev/null +++ b/net/batman-adv/tp_meter.c @@ -0,0 +1,1505 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2012-2018 B.A.T.M.A.N. contributors: + * + * Edo Monticelli, Antonio Quartulli + * + * 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 "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/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/kernel.h> +#include <linux/kref.h> +#include <linux/kthread.h> +#include <linux/list.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 amound 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: minumim cwnd value (usually MSS) + * + * Return the new cwnd size and ensures it does not exceed the Advertised + * Receiver Window size. It is wrap around safe. + * 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_updated_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 incremented 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 incremented 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) +{ + 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; + size_t packet_len, mss; + u32 rtt, recv_ack, cwnd; + unsigned char *dev_addr; + + 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: + if (likely(primary_if)) + batadv_hardif_put(primary_if); + if (likely(orig_node)) + batadv_orig_node_put(orig_node); + if (likely(tp_vars)) + 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: + if (likely(primary_if)) + batadv_hardif_put(primary_if); + if (likely(orig_node)) + 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); + + do_exit(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: + if (likely(orig_node)) + batadv_orig_node_put(orig_node); + if (likely(primary_if)) + 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: + if (likely(tp_vars)) + 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)); +} |