mesh_hwmp.c 23.9 KB
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/*
 * Copyright (c) 2008 open80211s Ltd.
 * Author:     Luis Carlos Cobo <luisca@cozybit.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include "mesh.h"

#define TEST_FRAME_LEN	8192
#define MAX_METRIC	0xffffffff
#define ARITH_SHIFT	8

/* Number of frames buffered per destination for unresolved destinations */
#define MESH_FRAME_QUEUE_LEN	10
#define MAX_PREQ_QUEUE_LEN	64

/* Destination only */
#define MP_F_DO	0x1
/* Reply and forward */
#define MP_F_RF	0x2

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static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
{
	if (ae)
		offset += 6;
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	return get_unaligned_le32(preq_elem + offset);
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}

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/* HWMP IE processing macros */
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#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_DSN(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_DST_F(x)	(*(AE_F_SET(x) ? x + 32 : x + 26))
#define PREQ_IE_DST_ADDR(x) 	(AE_F_SET(x) ? x + 33 : x + 27)
#define PREQ_IE_DST_DSN(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)	(x + 3)
#define PREP_IE_ORIG_DSN(x)	u32_field_get(x, 9, 0);
#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_DST_ADDR(x)	(AE_F_SET(x) ? x + 27 : x + 21)
#define PREP_IE_DST_DSN(x)	u32_field_get(x, 27, AE_F_SET(x));

#define PERR_IE_DST_ADDR(x)	(x + 2)
#define PERR_IE_DST_DSN(x)	u32_field_get(x, 8, 0);
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#define TU_TO_EXP_TIME(x) (jiffies + msecs_to_jiffies(x * 1024 / 1000))
#define MSEC_TO_TU(x) (x*1000/1024)
#define DSN_GT(x, y) ((long) (y) - (long) (x) < 0)
#define DSN_LT(x, y) ((long) (x) - (long) (y) < 0)

#define net_traversal_jiffies(s) \
	msecs_to_jiffies(s->u.sta.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
#define default_lifetime(s) \
	MSEC_TO_TU(s->u.sta.mshcfg.dot11MeshHWMPactivePathTimeout)
#define min_preq_int_jiff(s) \
	(msecs_to_jiffies(s->u.sta.mshcfg.dot11MeshHWMPpreqMinInterval))
#define max_preq_retries(s) (s->u.sta.mshcfg.dot11MeshHWMPmaxPREQretries)
#define disc_timeout_jiff(s) \
	msecs_to_jiffies(sdata->u.sta.mshcfg.min_discovery_timeout)

enum mpath_frame_type {
	MPATH_PREQ = 0,
	MPATH_PREP,
	MPATH_PERR
};

static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
		u8 *orig_addr, __le32 orig_dsn, u8 dst_flags, u8 *dst,
		__le32 dst_dsn, u8 *da, u8 hop_count, u8 ttl, __le32 lifetime,
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		__le32 metric, __le32 preq_id, struct ieee80211_sub_if_data *sdata)
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{
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	struct ieee80211_local *local = sdata->local;
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	struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
	struct ieee80211_mgmt *mgmt;
	u8 *pos;
	int ie_len;

	if (!skb)
		return -1;
	skb_reserve(skb, local->hw.extra_tx_headroom);
	/* 25 is the size of the common mgmt part (24) plus the size of the
	 * common action part (1)
	 */
	mgmt = (struct ieee80211_mgmt *)
		skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
	memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
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	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
					  IEEE80211_STYPE_ACTION);
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	memcpy(mgmt->da, da, ETH_ALEN);
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	memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
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	/* BSSID is left zeroed, wildcard value */
	mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
	mgmt->u.action.u.mesh_action.action_code = action;

	switch (action) {
	case MPATH_PREQ:
		ie_len = 37;
		pos = skb_put(skb, 2 + ie_len);
		*pos++ = WLAN_EID_PREQ;
		break;
	case MPATH_PREP:
		ie_len = 31;
		pos = skb_put(skb, 2 + ie_len);
		*pos++ = WLAN_EID_PREP;
		break;
	default:
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		kfree_skb(skb);
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		return -ENOTSUPP;
		break;
	}
	*pos++ = ie_len;
	*pos++ = flags;
	*pos++ = hop_count;
	*pos++ = ttl;
	if (action == MPATH_PREQ) {
		memcpy(pos, &preq_id, 4);
		pos += 4;
	}
	memcpy(pos, orig_addr, ETH_ALEN);
	pos += ETH_ALEN;
	memcpy(pos, &orig_dsn, 4);
	pos += 4;
	memcpy(pos, &lifetime, 4);
	pos += 4;
	memcpy(pos, &metric, 4);
	pos += 4;
	if (action == MPATH_PREQ) {
		/* destination count */
		*pos++ = 1;
		*pos++ = dst_flags;
	}
	memcpy(pos, dst, ETH_ALEN);
	pos += ETH_ALEN;
	memcpy(pos, &dst_dsn, 4);

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	ieee80211_sta_tx(sdata, skb, 0);
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	return 0;
}

/**
 * mesh_send_path error - Sends a PERR mesh management frame
 *
 * @dst: broken destination
 * @dst_dsn: dsn of the broken destination
 * @ra: node this frame is addressed to
 */
int mesh_path_error_tx(u8 *dst, __le32 dst_dsn, u8 *ra,
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		struct ieee80211_sub_if_data *sdata)
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{
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	struct ieee80211_local *local = sdata->local;
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	struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
	struct ieee80211_mgmt *mgmt;
	u8 *pos;
	int ie_len;

	if (!skb)
		return -1;
	skb_reserve(skb, local->hw.extra_tx_headroom);
	/* 25 is the size of the common mgmt part (24) plus the size of the
	 * common action part (1)
	 */
	mgmt = (struct ieee80211_mgmt *)
		skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
	memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
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	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
					  IEEE80211_STYPE_ACTION);
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	memcpy(mgmt->da, ra, ETH_ALEN);
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	memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
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	/* BSSID is left zeroed, wildcard value */
	mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
	mgmt->u.action.u.mesh_action.action_code = MPATH_PERR;
	ie_len = 12;
	pos = skb_put(skb, 2 + ie_len);
	*pos++ = WLAN_EID_PERR;
	*pos++ = ie_len;
	/* mode flags, reserved */
	*pos++ = 0;
	/* number of destinations */
	*pos++ = 1;
	memcpy(pos, dst, ETH_ALEN);
	pos += ETH_ALEN;
	memcpy(pos, &dst_dsn, 4);

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	ieee80211_sta_tx(sdata, skb, 0);
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	return 0;
}

static u32 airtime_link_metric_get(struct ieee80211_local *local,
				   struct sta_info *sta)
{
	struct ieee80211_supported_band *sband;
	/* 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;

	sband = local->hw.wiphy->bands[local->hw.conf.channel->band];

	if (sta->fail_avg >= 100)
		return MAX_METRIC;
	err = (sta->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.
	 */
	rate = sband->bitrates[sta->txrate_idx].bitrate;
	tx_time = (device_constant + 10 * test_frame_len / rate);
	estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
	result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
	return (u32)result;
}

/**
 * hwmp_route_info_get - Update routing info to originator and transmitter
 *
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 * @sdata: local mesh subif
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 * @mgmt: mesh management frame
 * @hwmp_ie: hwmp information element (PREP or PREQ)
 *
 * This function updates the path routing information to the originator and the
 * transmitter of a HWMP PREQ or PREP fram.
 *
 * 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.
 */
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static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
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			    struct ieee80211_mgmt *mgmt,
			    u8 *hwmp_ie)
{
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	struct ieee80211_local *local = sdata->local;
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	struct mesh_path *mpath;
	struct sta_info *sta;
	bool fresh_info;
	u8 *orig_addr, *ta;
	u32 orig_dsn, orig_metric;
	unsigned long orig_lifetime, exp_time;
	u32 last_hop_metric, new_metric;
	bool process = true;
	u8 action = mgmt->u.action.u.mesh_action.action_code;

	rcu_read_lock();
	sta = sta_info_get(local, mgmt->sa);
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	if (!sta) {
		rcu_read_unlock();
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		return 0;
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	}
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	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_dsn = PREQ_IE_ORIG_DSN(hwmp_ie);
		orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
		orig_metric = PREQ_IE_METRIC(hwmp_ie);
		break;
	case MPATH_PREP:
		/* Originator here refers to the MP that was the destination in
		 * the Path Request. The draft refers to that MP as the
		 * destination address, even though usually it is the origin of
		 * the PREP frame. 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_ORIG_ADDR(hwmp_ie);
		orig_dsn = PREP_IE_ORIG_DSN(hwmp_ie);
		orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
		orig_metric = PREP_IE_METRIC(hwmp_ie);
		break;
	default:
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		rcu_read_unlock();
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		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);

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	if (memcmp(orig_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
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		/* 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 {
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		mpath = mesh_path_lookup(orig_addr, sdata);
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		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_DSN_VALID)) {
				if (DSN_GT(mpath->dsn, orig_dsn) ||
				    (mpath->dsn == orig_dsn &&
				     action == MPATH_PREQ &&
				     new_metric > mpath->metric)) {
					process = false;
					fresh_info = false;
				}
			}
		} else {
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			mesh_path_add(orig_addr, sdata);
			mpath = mesh_path_lookup(orig_addr, sdata);
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			if (!mpath) {
				rcu_read_unlock();
				return 0;
			}
			spin_lock_bh(&mpath->state_lock);
		}

		if (fresh_info) {
			mesh_path_assign_nexthop(mpath, sta);
			mpath->flags |= MESH_PATH_DSN_VALID;
			mpath->metric = new_metric;
			mpath->dsn = orig_dsn;
			mpath->exp_time = time_after(mpath->exp_time, exp_time)
					  ?  mpath->exp_time : exp_time;
			mesh_path_activate(mpath);
			spin_unlock_bh(&mpath->state_lock);
			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 (memcmp(orig_addr, ta, ETH_ALEN) == 0)
		fresh_info = false;
	else {
		fresh_info = true;

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		mpath = mesh_path_lookup(ta, sdata);
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		if (mpath) {
			spin_lock_bh(&mpath->state_lock);
			if ((mpath->flags & MESH_PATH_FIXED) ||
				((mpath->flags & MESH_PATH_ACTIVE) &&
					(last_hop_metric > mpath->metric)))
				fresh_info = false;
		} else {
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			mesh_path_add(ta, sdata);
			mpath = mesh_path_lookup(ta, sdata);
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			if (!mpath) {
				rcu_read_unlock();
				return 0;
			}
			spin_lock_bh(&mpath->state_lock);
		}

		if (fresh_info) {
			mesh_path_assign_nexthop(mpath, sta);
			mpath->flags &= ~MESH_PATH_DSN_VALID;
			mpath->metric = last_hop_metric;
			mpath->exp_time = time_after(mpath->exp_time, exp_time)
					  ?  mpath->exp_time : exp_time;
			mesh_path_activate(mpath);
			spin_unlock_bh(&mpath->state_lock);
			mesh_path_tx_pending(mpath);
		} else
			spin_unlock_bh(&mpath->state_lock);
	}

	rcu_read_unlock();

	return process ? new_metric : 0;
}

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static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
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				    struct ieee80211_mgmt *mgmt,
				    u8 *preq_elem, u32 metric) {
	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
	struct mesh_path *mpath;
	u8 *dst_addr, *orig_addr;
	u8 dst_flags, ttl;
	u32 orig_dsn, dst_dsn, lifetime;
	bool reply = false;
	bool forward = true;

	/* Update destination DSN, if present */
	dst_addr = PREQ_IE_DST_ADDR(preq_elem);
	orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
	dst_dsn = PREQ_IE_DST_DSN(preq_elem);
	orig_dsn = PREQ_IE_ORIG_DSN(preq_elem);
	dst_flags = PREQ_IE_DST_F(preq_elem);

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	if (memcmp(dst_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
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		forward = false;
		reply = true;
		metric = 0;
		if (time_after(jiffies, ifsta->last_dsn_update +
					net_traversal_jiffies(sdata)) ||
		    time_before(jiffies, ifsta->last_dsn_update)) {
			dst_dsn = ++ifsta->dsn;
			ifsta->last_dsn_update = jiffies;
		}
	} else {
		rcu_read_lock();
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		mpath = mesh_path_lookup(dst_addr, sdata);
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		if (mpath) {
			if ((!(mpath->flags & MESH_PATH_DSN_VALID)) ||
					DSN_LT(mpath->dsn, dst_dsn)) {
				mpath->dsn = dst_dsn;
				mpath->flags &= MESH_PATH_DSN_VALID;
			} else if ((!(dst_flags & MP_F_DO)) &&
					(mpath->flags & MESH_PATH_ACTIVE)) {
				reply = true;
				metric = mpath->metric;
				dst_dsn = mpath->dsn;
				if (dst_flags & MP_F_RF)
					dst_flags |= MP_F_DO;
				else
					forward = false;
			}
		}
		rcu_read_unlock();
	}

	if (reply) {
		lifetime = PREQ_IE_LIFETIME(preq_elem);
		ttl = ifsta->mshcfg.dot11MeshTTL;
		if (ttl != 0)
			mesh_path_sel_frame_tx(MPATH_PREP, 0, dst_addr,
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				cpu_to_le32(dst_dsn), 0, orig_addr,
				cpu_to_le32(orig_dsn), mgmt->sa, 0, ttl,
				cpu_to_le32(lifetime), cpu_to_le32(metric),
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				0, sdata);
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		else
			ifsta->mshstats.dropped_frames_ttl++;
	}

	if (forward) {
		u32 preq_id;
		u8 hopcount, flags;

		ttl = PREQ_IE_TTL(preq_elem);
		lifetime = PREQ_IE_LIFETIME(preq_elem);
		if (ttl <= 1) {
			ifsta->mshstats.dropped_frames_ttl++;
			return;
		}
		--ttl;
		flags = PREQ_IE_FLAGS(preq_elem);
		preq_id = PREQ_IE_PREQ_ID(preq_elem);
		hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
		mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
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				cpu_to_le32(orig_dsn), dst_flags, dst_addr,
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				cpu_to_le32(dst_dsn), sdata->dev->broadcast,
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				hopcount, ttl, cpu_to_le32(lifetime),
				cpu_to_le32(metric), cpu_to_le32(preq_id),
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				sdata);
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		ifsta->mshstats.fwded_frames++;
	}
}


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static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
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				    struct ieee80211_mgmt *mgmt,
				    u8 *prep_elem, u32 metric)
{
	struct mesh_path *mpath;
	u8 *dst_addr, *orig_addr;
	u8 ttl, hopcount, flags;
	u8 next_hop[ETH_ALEN];
	u32 dst_dsn, orig_dsn, lifetime;

	/* Note that we divert from the draft nomenclature and denominate
	 * destination to what the draft refers to as origininator. So in this
	 * function destnation refers to the final destination of the PREP,
	 * which corresponds with the originator of the PREQ which this PREP
	 * replies
	 */
	dst_addr = PREP_IE_DST_ADDR(prep_elem);
500
	if (memcmp(dst_addr, sdata->dev->dev_addr, ETH_ALEN) == 0)
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		/* destination, no forwarding required */
		return;

	ttl = PREP_IE_TTL(prep_elem);
	if (ttl <= 1) {
		sdata->u.sta.mshstats.dropped_frames_ttl++;
		return;
	}

	rcu_read_lock();
511
	mpath = mesh_path_lookup(dst_addr, sdata);
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	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, mpath->next_hop->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;
	orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
	dst_dsn = PREP_IE_DST_DSN(prep_elem);
	orig_dsn = PREP_IE_ORIG_DSN(prep_elem);

	mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
531
532
533
		cpu_to_le32(orig_dsn), 0, dst_addr,
		cpu_to_le32(dst_dsn), mpath->next_hop->addr, hopcount, ttl,
		cpu_to_le32(lifetime), cpu_to_le32(metric),
534
		0, sdata);
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541
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544
	rcu_read_unlock();
	sdata->u.sta.mshstats.fwded_frames++;
	return;

fail:
	rcu_read_unlock();
	sdata->u.sta.mshstats.dropped_frames_no_route++;
	return;
}

545
static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
546
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555
			     struct ieee80211_mgmt *mgmt, u8 *perr_elem)
{
	struct mesh_path *mpath;
	u8 *ta, *dst_addr;
	u32 dst_dsn;

	ta = mgmt->sa;
	dst_addr = PERR_IE_DST_ADDR(perr_elem);
	dst_dsn = PERR_IE_DST_DSN(perr_elem);
	rcu_read_lock();
556
	mpath = mesh_path_lookup(dst_addr, sdata);
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	if (mpath) {
		spin_lock_bh(&mpath->state_lock);
		if (mpath->flags & MESH_PATH_ACTIVE &&
		    memcmp(ta, mpath->next_hop->addr, ETH_ALEN) == 0 &&
		    (!(mpath->flags & MESH_PATH_DSN_VALID) ||
		    DSN_GT(dst_dsn, mpath->dsn))) {
			mpath->flags &= ~MESH_PATH_ACTIVE;
			mpath->dsn = dst_dsn;
			spin_unlock_bh(&mpath->state_lock);
566
			mesh_path_error_tx(dst_addr, cpu_to_le32(dst_dsn),
567
					   sdata->dev->broadcast, sdata);
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		} else
			spin_unlock_bh(&mpath->state_lock);
	}
	rcu_read_unlock();
}



576
void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
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			    struct ieee80211_mgmt *mgmt,
			    size_t len)
{
	struct ieee802_11_elems elems;
	size_t baselen;
	u32 last_hop_metric;

	baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
	ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
			len - baselen, &elems);

	switch (mgmt->u.action.u.mesh_action.action_code) {
	case MPATH_PREQ:
		if (!elems.preq || elems.preq_len != 37)
			/* Right now we support just 1 destination and no AE */
			return;
593
		last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq);
594
595
		if (!last_hop_metric)
			return;
596
		hwmp_preq_frame_process(sdata, mgmt, elems.preq, last_hop_metric);
597
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599
600
601
		break;
	case MPATH_PREP:
		if (!elems.prep || elems.prep_len != 31)
			/* Right now we support no AE */
			return;
602
		last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep);
603
604
		if (!last_hop_metric)
			return;
605
		hwmp_prep_frame_process(sdata, mgmt, elems.prep, last_hop_metric);
606
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608
609
610
		break;
	case MPATH_PERR:
		if (!elems.perr || elems.perr_len != 12)
			/* Right now we support only one destination per PERR */
			return;
611
		hwmp_perr_frame_process(sdata, mgmt, elems.perr);
612
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615
616
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627
628
	default:
		return;
	}

}

/**
 * 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)
{
629
	struct ieee80211_sub_if_data *sdata = mpath->sdata;
630
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640
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644
645
646
647
648
649
650
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654
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664
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669
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671
	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
	struct mesh_preq_queue *preq_node;

	preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_KERNEL);
	if (!preq_node) {
		printk(KERN_DEBUG "Mesh HWMP: could not allocate PREQ node\n");
		return;
	}

	spin_lock(&ifsta->mesh_preq_queue_lock);
	if (ifsta->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
		spin_unlock(&ifsta->mesh_preq_queue_lock);
		kfree(preq_node);
		if (printk_ratelimit())
			printk(KERN_DEBUG "Mesh HWMP: PREQ node queue full\n");
		return;
	}

	memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
	preq_node->flags = flags;

	list_add_tail(&preq_node->list, &ifsta->preq_queue.list);
	++ifsta->preq_queue_len;
	spin_unlock(&ifsta->mesh_preq_queue_lock);

	if (time_after(jiffies, ifsta->last_preq + min_preq_int_jiff(sdata)))
		queue_work(sdata->local->hw.workqueue, &ifsta->work);

	else if (time_before(jiffies, ifsta->last_preq)) {
		/* avoid long wait if did not send preqs for a long time
		 * and jiffies wrapped around
		 */
		ifsta->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
		queue_work(sdata->local->hw.workqueue, &ifsta->work);
	} else
		mod_timer(&ifsta->mesh_path_timer, ifsta->last_preq +
						min_preq_int_jiff(sdata));
}

/**
 * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 *
672
 * @sdata: local mesh subif
673
 */
674
void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
{
	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
	struct mesh_preq_queue *preq_node;
	struct mesh_path *mpath;
	u8 ttl, dst_flags;
	u32 lifetime;

	spin_lock(&ifsta->mesh_preq_queue_lock);
	if (!ifsta->preq_queue_len ||
		time_before(jiffies, ifsta->last_preq +
				min_preq_int_jiff(sdata))) {
		spin_unlock(&ifsta->mesh_preq_queue_lock);
		return;
	}

	preq_node = list_first_entry(&ifsta->preq_queue.list,
			struct mesh_preq_queue, list);
	list_del(&preq_node->list);
	--ifsta->preq_queue_len;
	spin_unlock(&ifsta->mesh_preq_queue_lock);

	rcu_read_lock();
697
	mpath = mesh_path_lookup(preq_node->dst, sdata);
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
	if (!mpath)
		goto enddiscovery;

	spin_lock_bh(&mpath->state_lock);
	if (preq_node->flags & PREQ_Q_F_START) {
		if (mpath->flags & MESH_PATH_RESOLVING) {
			spin_unlock_bh(&mpath->state_lock);
			goto enddiscovery;
		} else {
			mpath->flags &= ~MESH_PATH_RESOLVED;
			mpath->flags |= MESH_PATH_RESOLVING;
			mpath->discovery_retries = 0;
			mpath->discovery_timeout = disc_timeout_jiff(sdata);
		}
	} else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
			mpath->flags & MESH_PATH_RESOLVED) {
		mpath->flags &= ~MESH_PATH_RESOLVING;
		spin_unlock_bh(&mpath->state_lock);
		goto enddiscovery;
	}

	ifsta->last_preq = jiffies;

	if (time_after(jiffies, ifsta->last_dsn_update +
				net_traversal_jiffies(sdata)) ||
	    time_before(jiffies, ifsta->last_dsn_update)) {
		++ifsta->dsn;
		sdata->u.sta.last_dsn_update = jiffies;
	}
	lifetime = default_lifetime(sdata);
	ttl = sdata->u.sta.mshcfg.dot11MeshTTL;
	if (ttl == 0) {
		sdata->u.sta.mshstats.dropped_frames_ttl++;
		spin_unlock_bh(&mpath->state_lock);
		goto enddiscovery;
	}

	if (preq_node->flags & PREQ_Q_F_REFRESH)
		dst_flags = MP_F_DO;
	else
		dst_flags = MP_F_RF;

	spin_unlock_bh(&mpath->state_lock);
741
	mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->dev->dev_addr,
742
			cpu_to_le32(ifsta->dsn), dst_flags, mpath->dst,
743
			cpu_to_le32(mpath->dsn), sdata->dev->broadcast, 0,
744
			ttl, cpu_to_le32(lifetime), 0,
745
			cpu_to_le32(ifsta->preq_id++), sdata);
746
747
748
749
750
751
752
753
754
755
	mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);

enddiscovery:
	rcu_read_unlock();
	kfree(preq_node);
}

/**
 * ieee80211s_lookup_nexthop - put the appropriate next hop on a mesh frame
 *
756
 * @skb: 802.11 frame to be sent
757
 * @sdata: network subif the frame will be sent through
758
 * @fwd_frame: true if this frame was originally from a different host
759
760
761
762
763
764
 *
 * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
 * found, the function will start a path discovery and queue the frame so it is
 * sent when the path is resolved. This means the caller must not free the skb
 * in this case.
 */
765
766
int mesh_nexthop_lookup(struct sk_buff *skb,
			struct ieee80211_sub_if_data *sdata)
767
768
769
{
	struct sk_buff *skb_to_free = NULL;
	struct mesh_path *mpath;
770
771
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
	u8 *dst_addr = hdr->addr3;
772
773
774
	int err = 0;

	rcu_read_lock();
775
	mpath = mesh_path_lookup(dst_addr, sdata);
776
777

	if (!mpath) {
778
779
		mesh_path_add(dst_addr, sdata);
		mpath = mesh_path_lookup(dst_addr, sdata);
780
781
782
783
784
785
786
787
788
789
790
		if (!mpath) {
			dev_kfree_skb(skb);
			sdata->u.sta.mshstats.dropped_frames_no_route++;
			err = -ENOSPC;
			goto endlookup;
		}
	}

	if (mpath->flags & MESH_PATH_ACTIVE) {
		if (time_after(jiffies, mpath->exp_time -
			msecs_to_jiffies(sdata->u.sta.mshcfg.path_refresh_time))
791
792
				&& !memcmp(sdata->dev->dev_addr, hdr->addr4,
					   ETH_ALEN)
793
794
795
796
797
				&& !(mpath->flags & MESH_PATH_RESOLVING)
				&& !(mpath->flags & MESH_PATH_FIXED)) {
			mesh_queue_preq(mpath,
					PREQ_Q_F_START | PREQ_Q_F_REFRESH);
		}
798
		memcpy(hdr->addr1, mpath->next_hop->addr,
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
				ETH_ALEN);
	} else {
		if (!(mpath->flags & MESH_PATH_RESOLVING)) {
			/* Start discovery only if it is not running yet */
			mesh_queue_preq(mpath, PREQ_Q_F_START);
		}

		if (skb_queue_len(&mpath->frame_queue) >=
				MESH_FRAME_QUEUE_LEN) {
			skb_to_free = mpath->frame_queue.next;
			skb_unlink(skb_to_free, &mpath->frame_queue);
		}

		skb_queue_tail(&mpath->frame_queue, skb);
		if (skb_to_free)
814
			mesh_path_discard_frame(skb_to_free, sdata);
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
		err = -ENOENT;
	}

endlookup:
	rcu_read_unlock();
	return err;
}

void mesh_path_timer(unsigned long data)
{
	struct ieee80211_sub_if_data *sdata;
	struct mesh_path *mpath;

	rcu_read_lock();
	mpath = (struct mesh_path *) data;
	mpath = rcu_dereference(mpath);
	if (!mpath)
		goto endmpathtimer;
	spin_lock_bh(&mpath->state_lock);
834
	sdata = mpath->sdata;
835
	if (mpath->flags & MESH_PATH_RESOLVED ||
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
			(!(mpath->flags & MESH_PATH_RESOLVING)))
		mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
	else if (mpath->discovery_retries < max_preq_retries(sdata)) {
		++mpath->discovery_retries;
		mpath->discovery_timeout *= 2;
		mesh_queue_preq(mpath, 0);
	} else {
		mpath->flags = 0;
		mpath->exp_time = jiffies;
		mesh_path_flush_pending(mpath);
	}

	spin_unlock_bh(&mpath->state_lock);
endmpathtimer:
	rcu_read_unlock();
}