path: root/net/mac80211/mesh_hwmp.c

/*
 * Copyright (c) 2008, 2009 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 <linux/slab.h>
#include <linux/etherdevice.h>
#include <asm/unaligned.h>
#include "wme.h"
#include "mesh.h"

#ifdef CONFIG_MAC80211_VERBOSE_MHWMP_DEBUG
#define mhwmp_dbg(fmt, args...) \
	printk(KERN_DEBUG "Mesh HWMP (%s): " fmt "\n", sdata->name, ##args)
#else
#define mhwmp_dbg(fmt, args...)   do { (void)(0); } while (0)
#endif

#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
/* Unknown Sequence Number */
#define MP_F_USN    0x01
/* Reason code Present */
#define MP_F_RCODE  0x02

static void mesh_queue_preq(struct mesh_path *, u8);

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

static inline u32 u16_field_get(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) ((long) (y) - (long) (x) < 0)
#define SN_LT(x, y) ((long) (x) - (long) (y) < 0)

#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)

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,
		u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
		__le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
		__le32 lifetime, __le32 metric, __le32 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 = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
		      sizeof(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 = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
	memset(mgmt, 0, 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