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mesh_hwmp.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2008, 2009 open80211s Ltd.
* Copyright (C) 2019, 2021-2023 Intel Corporation
* Author: Luis Carlos Cobo <[email protected]>
*/
#include <linux/slab.h>
#include <linux/etherdevice.h>
#include <asm/unaligned.h>
#include "wme.h"
#include "mesh.h"
#define TEST_FRAME_LEN 8192
#define MAX_METRIC 0xffffffff
#define ARITH_SHIFT 8
#define LINK_FAIL_THRESH 95
#define MAX_PREQ_QUEUE_LEN 64
static void mesh_queue_preq(struct mesh_path *, u8);
static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
{
if (ae)
offset += 6;
return get_unaligned_le32(preq_elem + offset);
}
static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae)
{
if (ae)
offset += 6;
return get_unaligned_le16(preq_elem + offset);
}
/* HWMP IE processing macros */
#define AE_F (1<<6)
#define AE_F_SET(x) (*x & AE_F)
#define PREQ_IE_FLAGS(x) (*(x))
#define PREQ_IE_HOPCOUNT(x) (*(x + 1))
#define PREQ_IE_TTL(x) (*(x + 2))
#define PREQ_IE_PREQ_ID(x) u32_field_get(x, 3, 0)
#define PREQ_IE_ORIG_ADDR(x) (x + 7)
#define PREQ_IE_ORIG_SN(x) u32_field_get(x, 13, 0)
#define PREQ_IE_LIFETIME(x) u32_field_get(x, 17, AE_F_SET(x))
#define PREQ_IE_METRIC(x) u32_field_get(x, 21, AE_F_SET(x))
#define PREQ_IE_TARGET_F(x) (*(AE_F_SET(x) ? x + 32 : x + 26))
#define PREQ_IE_TARGET_ADDR(x) (AE_F_SET(x) ? x + 33 : x + 27)
#define PREQ_IE_TARGET_SN(x) u32_field_get(x, 33, AE_F_SET(x))
#define PREP_IE_FLAGS(x) PREQ_IE_FLAGS(x)
#define PREP_IE_HOPCOUNT(x) PREQ_IE_HOPCOUNT(x)
#define PREP_IE_TTL(x) PREQ_IE_TTL(x)
#define PREP_IE_ORIG_ADDR(x) (AE_F_SET(x) ? x + 27 : x + 21)
#define PREP_IE_ORIG_SN(x) u32_field_get(x, 27, AE_F_SET(x))
#define PREP_IE_LIFETIME(x) u32_field_get(x, 13, AE_F_SET(x))
#define PREP_IE_METRIC(x) u32_field_get(x, 17, AE_F_SET(x))
#define PREP_IE_TARGET_ADDR(x) (x + 3)
#define PREP_IE_TARGET_SN(x) u32_field_get(x, 9, 0)
#define PERR_IE_TTL(x) (*(x))
#define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
#define PERR_IE_TARGET_ADDR(x) (x + 3)
#define PERR_IE_TARGET_SN(x) u32_field_get(x, 9, 0)
#define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
#define MSEC_TO_TU(x) (x*1000/1024)
#define SN_GT(x, y) ((s32)(y - x) < 0)
#define SN_LT(x, y) ((s32)(x - y) < 0)
#define MAX_SANE_SN_DELTA 32
static inline u32 SN_DELTA(u32 x, u32 y)
{
return x >= y ? x - y : y - x;
}
#define net_traversal_jiffies(s) \
msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
#define default_lifetime(s) \
MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
#define min_preq_int_jiff(s) \
(msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
#define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
#define disc_timeout_jiff(s) \
msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
#define root_path_confirmation_jiffies(s) \
msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
enum mpath_frame_type {
MPATH_PREQ = 0,
MPATH_PREP,
MPATH_PERR,
MPATH_RANN
};
static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
const u8 *orig_addr, u32 orig_sn,
u8 target_flags, const u8 *target,
u32 target_sn, const u8 *da,
u8 hop_count, u8 ttl,
u32 lifetime, u32 metric, u32 preq_id,
struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_local *local = sdata->local;
struct sk_buff *skb;
struct ieee80211_mgmt *mgmt;
u8 *pos, ie_len;
int hdr_len = offsetofend(struct ieee80211_mgmt,
u.action.u.mesh_action);
skb = dev_alloc_skb(local->tx_headroom +
hdr_len +
2 + 37); /* max HWMP IE */
if (!skb)
return -1;
skb_reserve(skb, local->tx_headroom);
mgmt = skb_put_zero(skb, hdr_len);
mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
IEEE80211_STYPE_ACTION);
memcpy(mgmt->da, da, ETH_ALEN);
memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
/* BSSID == SA */
memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
mgmt->u.action.u.mesh_action.action_code =
WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
switch (action) {
case MPATH_PREQ:
mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
ie_len = 37;
pos = skb_put(skb, 2 + ie_len);
*pos++ = WLAN_EID_PREQ;
break;
case MPATH_PREP:
mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
ie_len = 31;
pos = skb_put(skb, 2 + ie_len);
*pos++ = WLAN_EID_PREP;
break;
case MPATH_RANN:
mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
ie_len = sizeof(struct ieee80211_rann_ie);
pos = skb_put(skb, 2 + ie_len);
*pos++ = WLAN_EID_RANN;
break;
default:
kfree_skb(skb);
return -ENOTSUPP;
}
*pos++ = ie_len;
*pos++ = flags;
*pos++ = hop_count;
*pos++ = ttl;
if (action == MPATH_PREP) {
memcpy(pos, target, ETH_ALEN);
pos += ETH_ALEN;
put_unaligned_le32(target_sn, pos);
pos += 4;
} else {
if (action == MPATH_PREQ) {
put_unaligned_le32(preq_id, pos);
pos += 4;
}
memcpy(pos, orig_addr, ETH_ALEN);
pos += ETH_ALEN;
put_unaligned_le32(orig_sn, pos);
pos += 4;
}
put_unaligned_le32(lifetime, pos); /* interval for RANN */
pos += 4;
put_unaligned_le32(metric, pos);
pos += 4;
if (action == MPATH_PREQ) {
*pos++ = 1; /* destination count */
*pos++ = target_flags;
memcpy(pos, target, ETH_ALEN);
pos += ETH_ALEN;
put_unaligned_le32(target_sn, pos);
pos += 4;
} else if (action == MPATH_PREP) {
memcpy(pos, orig_addr, ETH_ALEN);
pos += ETH_ALEN;
put_unaligned_le32(orig_sn, pos);
pos += 4;
}
ieee80211_tx_skb(sdata, skb);
return 0;
}
/* Headroom is not adjusted. Caller should ensure that skb has sufficient
* headroom in case the frame is encrypted. */
static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
struct sk_buff *skb)
{
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
skb_reset_mac_header(skb);
skb_reset_network_header(skb);
skb_reset_transport_header(skb);
/* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
skb_set_queue_mapping(skb, IEEE80211_AC_VO);
skb->priority = 7;
info->control.vif = &sdata->vif;
info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
ieee80211_set_qos_hdr(sdata, skb);
ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
}
/**
* mesh_path_error_tx - Sends a PERR mesh management frame
*
* @ttl: allowed remaining hops
* @target: broken destination
* @target_sn: SN of the broken destination
* @target_rcode: reason code for this PERR
* @ra: node this frame is addressed to
* @sdata: local mesh subif
*
* Note: This function may be called with driver locks taken that the driver
* also acquires in the TX path. To avoid a deadlock we don't transmit the
* frame directly but add it to the pending queue instead.
*/
int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
u8 ttl, const u8 *target, u32 target_sn,
u16 target_rcode, const u8 *ra)
{
struct ieee80211_local *local = sdata->local;
struct sk_buff *skb;
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
struct ieee80211_mgmt *mgmt;
u8 *pos, ie_len;
int hdr_len = offsetofend(struct ieee80211_mgmt,
u.action.u.mesh_action);
if (time_before(jiffies, ifmsh->next_perr))
return -EAGAIN;
skb = dev_alloc_skb(local->tx_headroom +
IEEE80211_ENCRYPT_HEADROOM +
IEEE80211_ENCRYPT_TAILROOM +
hdr_len +
2 + 15 /* PERR IE */);
if (!skb)
return -1;
skb_reserve(skb, local->tx_headroom + IEEE80211_ENCRYPT_HEADROOM);
mgmt = skb_put_zero(skb, hdr_len);
mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
IEEE80211_STYPE_ACTION);
memcpy(mgmt->da, ra, ETH_ALEN);
memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
/* BSSID == SA */
memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
mgmt->u.action.u.mesh_action.action_code =
WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
ie_len = 15;
pos = skb_put(skb, 2 + ie_len);
*pos++ = WLAN_EID_PERR;
*pos++ = ie_len;
/* ttl */
*pos++ = ttl;
/* number of destinations */
*pos++ = 1;
/* Flags field has AE bit only as defined in
* sec 8.4.2.117 IEEE802.11-2012
*/
*pos = 0;
pos++;
memcpy(pos, target, ETH_ALEN);
pos += ETH_ALEN;
put_unaligned_le32(target_sn, pos);
pos += 4;
put_unaligned_le16(target_rcode, pos);
/* see note in function header */
prepare_frame_for_deferred_tx(sdata, skb);
ifmsh->next_perr = TU_TO_EXP_TIME(
ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
ieee80211_add_pending_skb(local, skb);
return 0;
}
void ieee80211s_update_metric(struct ieee80211_local *local,
struct sta_info *sta,
struct ieee80211_tx_status *st)
{
struct ieee80211_tx_info *txinfo = st->info;
int failed;
struct rate_info rinfo;
failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
/* moving average, scaled to 100.
* feed failure as 100 and success as 0
*/
ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100);
if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) >
LINK_FAIL_THRESH)
mesh_plink_broken(sta);
/* use rate info set by the driver directly if present */
if (st->n_rates)
rinfo = sta->deflink.tx_stats.last_rate_info;
else
sta_set_rate_info_tx(sta, &sta->deflink.tx_stats.last_rate, &rinfo);
ewma_mesh_tx_rate_avg_add(&sta->mesh->tx_rate_avg,
cfg80211_calculate_bitrate(&rinfo));
}
u32 airtime_link_metric_get(struct ieee80211_local *local,
struct sta_info *sta)
{
/* This should be adjusted for each device */
int device_constant = 1 << ARITH_SHIFT;
int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
int s_unit = 1 << ARITH_SHIFT;
int rate, err;
u32 tx_time, estimated_retx;
u64 result;
unsigned long fail_avg =
ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
if (sta->mesh->plink_state != NL80211_PLINK_ESTAB)
return MAX_METRIC;
/* Try to get rate based on HW/SW RC algorithm.
* Rate is returned in units of Kbps, correct this
* to comply with airtime calculation units
* Round up in case we get rate < 100Kbps
*/
rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
if (rate) {
err = 0;
} else {
if (fail_avg > LINK_FAIL_THRESH)
return MAX_METRIC;
rate = ewma_mesh_tx_rate_avg_read(&sta->mesh->tx_rate_avg);
if (WARN_ON(!rate))
return MAX_METRIC;
err = (fail_avg << ARITH_SHIFT) / 100;
}
/* bitrate is in units of 100 Kbps, while we need rate in units of
* 1Mbps. This will be corrected on tx_time computation.
*/
tx_time = (device_constant + 10 * test_frame_len / rate);
estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
result = ((u64)tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
return (u32)result;
}
/**
* hwmp_route_info_get - Update routing info to originator and transmitter
*
* @sdata: local mesh subif
* @mgmt: mesh management frame
* @hwmp_ie: hwmp information element (PREP or PREQ)
* @action: type of hwmp ie
*
* This function updates the path routing information to the originator and the
* transmitter of a HWMP PREQ or PREP frame.
*
* Returns: metric to frame originator or 0 if the frame should not be further
* processed
*
* Notes: this function is the only place (besides user-provided info) where
* path routing information is updated.
*/
static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
struct ieee80211_mgmt *mgmt,
const u8 *hwmp_ie, enum mpath_frame_type action)
{
struct ieee80211_local *local = sdata->local;
struct mesh_path *mpath;
struct sta_info *sta;
bool fresh_info;
const u8 *orig_addr, *ta;
u32 orig_sn, orig_metric;
unsigned long orig_lifetime, exp_time;
u32 last_hop_metric, new_metric;
bool flush_mpath = false;
bool process = true;
u8 hopcount;
rcu_read_lock();
sta = sta_info_get(sdata, mgmt->sa);
if (!sta) {
rcu_read_unlock();
return 0;
}
last_hop_metric = airtime_link_metric_get(local, sta);
/* Update and check originator routing info */
fresh_info = true;
switch (action) {
case MPATH_PREQ:
orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
orig_metric = PREQ_IE_METRIC(hwmp_ie);
hopcount = PREQ_IE_HOPCOUNT(hwmp_ie) + 1;
break;
case MPATH_PREP:
/* Originator here refers to the MP that was the target in the
* Path Request. We divert from the nomenclature in the draft
* so that we can easily use a single function to gather path
* information from both PREQ and PREP frames.
*/
orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
orig_metric = PREP_IE_METRIC(hwmp_ie);
hopcount = PREP_IE_HOPCOUNT(hwmp_ie) + 1;
break;
default:
rcu_read_unlock();
return 0;
}
new_metric = orig_metric + last_hop_metric;
if (new_metric < orig_metric)
new_metric = MAX_METRIC;
exp_time = TU_TO_EXP_TIME(orig_lifetime);
if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
/* This MP is the originator, we are not interested in this
* frame, except for updating transmitter's path info.
*/
process = false;
fresh_info = false;
} else {
mpath = mesh_path_lookup(sdata, orig_addr);
if (mpath) {
spin_lock_bh(&mpath->state_lock);
if (mpath->flags & MESH_PATH_FIXED)
fresh_info = false;
else if ((mpath->flags & MESH_PATH_ACTIVE) &&
(mpath->flags & MESH_PATH_SN_VALID)) {
if (SN_GT(mpath->sn, orig_sn) ||
(mpath->sn == orig_sn &&
(rcu_access_pointer(mpath->next_hop) !=
sta ?
mult_frac(new_metric, 10, 9) :
new_metric) >= mpath->metric)) {
process = false;
fresh_info = false;
}
} else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
bool have_sn, newer_sn, bounced;
have_sn = mpath->flags & MESH_PATH_SN_VALID;
newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
bounced = have_sn &&
(SN_DELTA(orig_sn, mpath->sn) >
MAX_SANE_SN_DELTA);
if (!have_sn || newer_sn) {
/* if SN is newer than what we had
* then we can take it */;
} else if (bounced) {
/* if SN is way different than what
* we had then assume the other side
* rebooted or restarted */;
} else {
process = false;
fresh_info = false;
}
}
} else {
mpath = mesh_path_add(sdata, orig_addr);
if (IS_ERR(mpath)) {
rcu_read_unlock();
return 0;
}
spin_lock_bh(&mpath->state_lock);
}
if (fresh_info) {
if (rcu_access_pointer(mpath->next_hop) != sta) {
mpath->path_change_count++;
flush_mpath = true;
}
mesh_path_assign_nexthop(mpath, sta);
mpath->flags |= MESH_PATH_SN_VALID;
mpath->metric = new_metric;
mpath->sn = orig_sn;
mpath->exp_time = time_after(mpath->exp_time, exp_time)
? mpath->exp_time : exp_time;
mpath->hop_count = hopcount;
mesh_path_activate(mpath);
spin_unlock_bh(&mpath->state_lock);
if (flush_mpath)
mesh_fast_tx_flush_mpath(mpath);
ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
/* init it at a low value - 0 start is tricky */
ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
mesh_path_tx_pending(mpath);
/* draft says preq_id should be saved to, but there does
* not seem to be any use for it, skipping by now
*/
} else
spin_unlock_bh(&mpath->state_lock);
}
/* Update and check transmitter routing info */
ta = mgmt->sa;
if (ether_addr_equal(orig_addr, ta))
fresh_info = false;
else {
fresh_info = true;
mpath = mesh_path_lookup(sdata, ta);
if (mpath) {
spin_lock_bh(&mpath->state_lock);
if ((mpath->flags & MESH_PATH_FIXED) ||
((mpath->flags & MESH_PATH_ACTIVE) &&
((rcu_access_pointer(mpath->next_hop) != sta ?
mult_frac(last_hop_metric, 10, 9) :
last_hop_metric) > mpath->metric)))
fresh_info = false;
} else {
mpath = mesh_path_add(sdata, ta);
if (IS_ERR(mpath)) {
rcu_read_unlock();
return 0;
}
spin_lock_bh(&mpath->state_lock);
}
if (fresh_info) {
if (rcu_access_pointer(mpath->next_hop) != sta) {
mpath->path_change_count++;
flush_mpath = true;
}
mesh_path_assign_nexthop(mpath, sta);
mpath->metric = last_hop_metric;
mpath->exp_time = time_after(mpath->exp_time, exp_time)
? mpath->exp_time : exp_time;
mpath->hop_count = 1;
mesh_path_activate(mpath);
spin_unlock_bh(&mpath->state_lock);
if (flush_mpath)
mesh_fast_tx_flush_mpath(mpath);
ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
/* init it at a low value - 0 start is tricky */
ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
mesh_path_tx_pending(mpath);
} else
spin_unlock_bh(&mpath->state_lock);
}
rcu_read_unlock();
return process ? new_metric : 0;
}
static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
struct ieee80211_mgmt *mgmt,
const u8 *preq_elem, u32 orig_metric)
{
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
struct mesh_path *mpath = NULL;
const u8 *target_addr, *orig_addr;
const u8 *da;
u8 target_flags, ttl, flags;
u32 orig_sn, target_sn, lifetime, target_metric = 0;
bool reply = false;
bool forward = true;
bool root_is_gate;
/* Update target SN, if present */
target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
target_sn = PREQ_IE_TARGET_SN(preq_elem);
orig_sn = PREQ_IE_ORIG_SN(preq_elem);
target_flags = PREQ_IE_TARGET_F(preq_elem);
/* Proactive PREQ gate announcements */
flags = PREQ_IE_FLAGS(preq_elem);
root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
if (ether_addr_equal(target_addr, sdata->vif.addr)) {
mhwmp_dbg(sdata, "PREQ is for us\n");
forward = false;
reply = true;
target_metric = 0;
if (SN_GT(target_sn, ifmsh->sn))
ifmsh->sn = target_sn;
if (time_after(jiffies, ifmsh->last_sn_update +
net_traversal_jiffies(sdata)) ||
time_before(jiffies, ifmsh->last_sn_update)) {
++ifmsh->sn;
ifmsh->last_sn_update = jiffies;
}
target_sn = ifmsh->sn;
} else if (is_broadcast_ether_addr(target_addr) &&
(target_flags & IEEE80211_PREQ_TO_FLAG)) {
rcu_read_lock();
mpath = mesh_path_lookup(sdata, orig_addr);
if (mpath) {
if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
reply = true;
target_addr = sdata->vif.addr;
target_sn = ++ifmsh->sn;
target_metric = 0;
ifmsh->last_sn_update = jiffies;
}
if (root_is_gate)
mesh_path_add_gate(mpath);
}
rcu_read_unlock();
} else {
rcu_read_lock();
mpath = mesh_path_lookup(sdata, target_addr);
if (mpath) {
if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
SN_LT(mpath->sn, target_sn)) {
mpath->sn = target_sn;
mpath->flags |= MESH_PATH_SN_VALID;
} else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
(mpath->flags & MESH_PATH_ACTIVE)) {
reply = true;
target_metric = mpath->metric;
target_sn = mpath->sn;
/* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
target_flags |= IEEE80211_PREQ_TO_FLAG;
}
}
rcu_read_unlock();
}
if (reply) {
lifetime = PREQ_IE_LIFETIME(preq_elem);
ttl = ifmsh->mshcfg.element_ttl;
if (ttl != 0) {
mhwmp_dbg(sdata, "replying to the PREQ\n");
mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
orig_sn, 0, target_addr,
target_sn, mgmt->sa, 0, ttl,
lifetime, target_metric, 0,
sdata);
} else {
ifmsh->mshstats.dropped_frames_ttl++;
}
}
if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
u32 preq_id;
u8 hopcount;
ttl = PREQ_IE_TTL(preq_elem);
lifetime = PREQ_IE_LIFETIME(preq_elem);
if (ttl <= 1) {
ifmsh->mshstats.dropped_frames_ttl++;
return;
}
mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
--ttl;
preq_id = PREQ_IE_PREQ_ID(preq_elem);
hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
da = (mpath && mpath->is_root) ?
mpath->rann_snd_addr : broadcast_addr;
if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
target_sn = PREQ_IE_TARGET_SN(preq_elem);
}
mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
orig_sn, target_flags, target_addr,
target_sn, da, hopcount, ttl, lifetime,
orig_metric, preq_id, sdata);
if (!is_multicast_ether_addr(da))
ifmsh->mshstats.fwded_unicast++;
else
ifmsh->mshstats.fwded_mcast++;
ifmsh->mshstats.fwded_frames++;
}
}
static inline struct sta_info *
next_hop_deref_protected(struct mesh_path *mpath)
{
return rcu_dereference_protected(mpath->next_hop,
lockdep_is_held(&mpath->state_lock));
}
static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
struct ieee80211_mgmt *mgmt,
const u8 *prep_elem, u32 metric)
{
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
struct mesh_path *mpath;
const u8 *target_addr, *orig_addr;
u8 ttl, hopcount, flags;
u8 next_hop[ETH_ALEN];
u32 target_sn, orig_sn, lifetime;
mhwmp_dbg(sdata, "received PREP from %pM\n",
PREP_IE_TARGET_ADDR(prep_elem));
orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
if (ether_addr_equal(orig_addr, sdata->vif.addr))
/* destination, no forwarding required */
return;
if (!ifmsh->mshcfg.dot11MeshForwarding)
return;
ttl = PREP_IE_TTL(prep_elem);
if (ttl <= 1) {
sdata->u.mesh.mshstats.dropped_frames_ttl++;
return;
}
rcu_read_lock();
mpath = mesh_path_lookup(sdata, orig_addr);
if (mpath)
spin_lock_bh(&mpath->state_lock);
else
goto fail;
if (!(mpath->flags & MESH_PATH_ACTIVE)) {
spin_unlock_bh(&mpath->state_lock);
goto fail;
}
memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
spin_unlock_bh(&mpath->state_lock);
--ttl;
flags = PREP_IE_FLAGS(prep_elem);
lifetime = PREP_IE_LIFETIME(prep_elem);
hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
target_addr = PREP_IE_TARGET_ADDR(prep_elem);
target_sn = PREP_IE_TARGET_SN(prep_elem);
orig_sn = PREP_IE_ORIG_SN(prep_elem);
mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
target_addr, target_sn, next_hop, hopcount,
ttl, lifetime, metric, 0, sdata);
rcu_read_unlock();
sdata->u.mesh.mshstats.fwded_unicast++;
sdata->u.mesh.mshstats.fwded_frames++;
return;
fail:
rcu_read_unlock();
sdata->u.mesh.mshstats.dropped_frames_no_route++;
}
static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
struct ieee80211_mgmt *mgmt,
const u8 *perr_elem)
{
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
struct mesh_path *mpath;
u8 ttl;
const u8 *ta, *target_addr;
u32 target_sn;
u16 target_rcode;
ta = mgmt->sa;
ttl = PERR_IE_TTL(perr_elem);
if (ttl <= 1) {
ifmsh->mshstats.dropped_frames_ttl++;
return;
}
ttl--;
target_addr = PERR_IE_TARGET_ADDR(perr_elem);
target_sn = PERR_IE_TARGET_SN(perr_elem);
target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
rcu_read_lock();
mpath = mesh_path_lookup(sdata, target_addr);
if (mpath) {
struct sta_info *sta;
spin_lock_bh(&mpath->state_lock);
sta = next_hop_deref_protected(mpath);
if (mpath->flags & MESH_PATH_ACTIVE &&
ether_addr_equal(ta, sta->sta.addr) &&
!(mpath->flags & MESH_PATH_FIXED) &&
(!(mpath->flags & MESH_PATH_SN_VALID) ||
SN_GT(target_sn, mpath->sn) || target_sn == 0)) {
mpath->flags &= ~MESH_PATH_ACTIVE;
if (target_sn != 0)
mpath->sn = target_sn;
else
mpath->sn += 1;
spin_unlock_bh(&mpath->state_lock);
if (!ifmsh->mshcfg.dot11MeshForwarding)
goto endperr;
mesh_path_error_tx(sdata, ttl, target_addr,
target_sn, target_rcode,
broadcast_addr);
} else
spin_unlock_bh(&mpath->state_lock);
}
endperr:
rcu_read_unlock();
}
static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
struct ieee80211_mgmt *mgmt,
const struct ieee80211_rann_ie *rann)
{
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
struct ieee80211_local *local = sdata->local;
struct sta_info *sta;
struct mesh_path *mpath;
u8 ttl, flags, hopcount;
const u8 *orig_addr;
u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
bool root_is_gate;
ttl = rann->rann_ttl;
flags = rann->rann_flags;
root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
orig_addr = rann->rann_addr;
orig_sn = le32_to_cpu(rann->rann_seq);
interval = le32_to_cpu(rann->rann_interval);
hopcount = rann->rann_hopcount;
hopcount++;
orig_metric = le32_to_cpu(rann->rann_metric);
/* Ignore our own RANNs */
if (ether_addr_equal(orig_addr, sdata->vif.addr))
return;
mhwmp_dbg(sdata,
"received RANN from %pM via neighbour %pM (is_gate=%d)\n",
orig_addr, mgmt->sa, root_is_gate);
rcu_read_lock();
sta = sta_info_get(sdata, mgmt->sa);
if (!sta) {
rcu_read_unlock();
return;
}
last_hop_metric = airtime_link_metric_get(local, sta);
new_metric = orig_metric + last_hop_metric;
if (new_metric < orig_metric)
new_metric = MAX_METRIC;
mpath = mesh_path_lookup(sdata, orig_addr);
if (!mpath) {
mpath = mesh_path_add(sdata, orig_addr);
if (IS_ERR(mpath)) {
rcu_read_unlock();
sdata->u.mesh.mshstats.dropped_frames_no_route++;
return;
}
}
if (!(SN_LT(mpath->sn, orig_sn)) &&
!(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
rcu_read_unlock();
return;
}
if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
(time_after(jiffies, mpath->last_preq_to_root +
root_path_confirmation_jiffies(sdata)) ||
time_before(jiffies, mpath->last_preq_to_root))) &&
!(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
mhwmp_dbg(sdata,
"time to refresh root mpath %pM\n",
orig_addr);
mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
mpath->last_preq_to_root = jiffies;
}
mpath->sn = orig_sn;
mpath->rann_metric = new_metric;
mpath->is_root = true;
/* Recording RANNs sender address to send individually
* addressed PREQs destined for root mesh STA */
memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
if (root_is_gate)
mesh_path_add_gate(mpath);
if (ttl <= 1) {
ifmsh->mshstats.dropped_frames_ttl++;
rcu_read_unlock();
return;
}
ttl--;
if (ifmsh->mshcfg.dot11MeshForwarding) {
mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
orig_sn, 0, NULL, 0, broadcast_addr,
hopcount, ttl, interval,
new_metric, 0, sdata);
}
rcu_read_unlock();
}
void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
struct ieee80211_mgmt *mgmt, size_t len)
{
struct ieee802_11_elems *elems;
size_t baselen;
u32 path_metric;
struct sta_info *sta;
/* need action_code */
if (len < IEEE80211_MIN_ACTION_SIZE + 1)
return;
rcu_read_lock();
sta = sta_info_get(sdata, mgmt->sa);
if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
rcu_read_unlock();
return;
}
rcu_read_unlock();
baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
elems = ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
len - baselen, false, NULL);
if (!elems)
return;
if (elems->preq) {
if (elems->preq_len != 37)
/* Right now we support just 1 destination and no AE */
goto free;
path_metric = hwmp_route_info_get(sdata, mgmt, elems->preq,
MPATH_PREQ);
if (path_metric)
hwmp_preq_frame_process(sdata, mgmt, elems->preq,
path_metric);
}
if (elems->prep) {
if (elems->prep_len != 31)
/* Right now we support no AE */
goto free;
path_metric = hwmp_route_info_get(sdata, mgmt, elems->prep,
MPATH_PREP);
if (path_metric)
hwmp_prep_frame_process(sdata, mgmt, elems->prep,
path_metric);
}
if (elems->perr) {
if (elems->perr_len != 15)
/* Right now we support only one destination per PERR */
goto free;
hwmp_perr_frame_process(sdata, mgmt, elems->perr);
}
if (elems->rann)
hwmp_rann_frame_process(sdata, mgmt, elems->rann);
free:
kfree(elems);
}
/**
* mesh_queue_preq - queue a PREQ to a given destination
*
* @mpath: mesh path to discover
* @flags: special attributes of the PREQ to be sent
*
* Locking: the function must be called from within a rcu read lock block.
*
*/
static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
{
struct ieee80211_sub_if_data *sdata = mpath->sdata;
struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
struct mesh_preq_queue *preq_node;
preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
if (!preq_node) {
mhwmp_dbg(sdata, "could not allocate PREQ node\n");
return;
}