mac80211: support functions for mesh
The two important features coded in mesh.c are: Recently Multicast Cache: in on-demand HWMP, multicast traffic is retransmitted by every receiving node. Even though a mesh TTL counter avoids infinite loops, it is also necessary to avoid traffic explosion by keeping a cache of multicast mesh frame that have been received recently. With this feature, maximum number of retransmissions of a multicast frame for the case of N nodes within the range of each other would be N. Without it, the maximum number of retransmissions would be in the order of N^(MESH_TTL - 1). Code to support mesh tables. Signed-off-by: Luis Carlos Cobo <luisca@cozybit.com> Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Luis Carlos Cobo
John W. Linville
parent
ccf80ddfe4
commit
2e3c873682
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/*
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* Copyright (c) 2008 open80211s Ltd.
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* Authors: Luis Carlos Cobo <luisca@cozybit.com>
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* Javier Cardona <javier@cozybit.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include "ieee80211_i.h"
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#include "mesh.h"
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#define PP_OFFSET 1 /* Path Selection Protocol */
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#define PM_OFFSET 5 /* Path Selection Metric */
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#define CC_OFFSET 9 /* Congestion Control Mode */
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#define CAPAB_OFFSET 17
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#define ACCEPT_PLINKS 0x80
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int mesh_allocated;
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static struct kmem_cache *rm_cache;
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void ieee80211s_init(void)
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{
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mesh_pathtbl_init();
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mesh_allocated = 1;
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rm_cache = kmem_cache_create("mesh_rmc", sizeof(struct rmc_entry),
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0, 0, NULL);
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}
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void ieee80211s_stop(void)
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{
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mesh_pathtbl_unregister();
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kmem_cache_destroy(rm_cache);
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}
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/**
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* mesh_matches_local - check if the config of a mesh point matches ours
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*
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* @ie: information elements of a management frame from the mesh peer
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* @dev: local mesh interface
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*
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* This function checks if the mesh configuration of a mesh point matches the
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* local mesh configuration, i.e. if both nodes belong to the same mesh network.
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*/
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bool mesh_matches_local(struct ieee802_11_elems *ie, struct net_device *dev)
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{
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struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
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struct ieee80211_if_sta *sta = &sdata->u.sta;
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if (sta->mesh_id_len == ie->mesh_id_len &&
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memcmp(sta->mesh_id, ie->mesh_id, ie->mesh_id_len) == 0 &&
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memcmp(sta->mesh_pp_id, ie->mesh_config + PP_OFFSET, 4) == 0 &&
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memcmp(sta->mesh_pm_id, ie->mesh_config + PM_OFFSET, 4) == 0 &&
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memcmp(sta->mesh_cc_id, ie->mesh_config + CC_OFFSET, 4) == 0)
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/*
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* As support for each feature is added, check for matching
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* - On mesh config capabilities
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* - Power Save Support En
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* - Sync support enabled
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* - Sync support active
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* - Sync support required from peer
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* - MDA enabled
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* - Power management control on fc
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*/
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return true;
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return false;
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}
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/**
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* mesh_peer_accepts_plinks - check if an mp is willing to establish peer links
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*
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* @ie: information elements of a management frame from the mesh peer
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* @dev: local mesh interface
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*/
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bool mesh_peer_accepts_plinks(struct ieee802_11_elems *ie,
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struct net_device *dev)
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{
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return (*(ie->mesh_config + CAPAB_OFFSET) & ACCEPT_PLINKS) != 0;
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}
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/**
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* mesh_accept_plinks_update: update accepting_plink in local mesh beacons
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*
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* @dev: mesh interface in which mesh beacons are going to be updated
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*/
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void mesh_accept_plinks_update(struct net_device *dev)
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{
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struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
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bool free_plinks;
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/* In case mesh_plink_free_count > 0 and mesh_plinktbl_capacity == 0,
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* the mesh interface might be able to establish plinks with peers that
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* are already on the table but are not on ESTAB state. However, in
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* general the mesh interface is not accepting peer link requests from
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* new peers, and that must be reflected in the beacon
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*/
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free_plinks = mesh_plink_availables(sdata);
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if (free_plinks != sdata->u.sta.accepting_plinks)
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ieee80211_sta_timer((unsigned long) sdata);
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}
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void mesh_ids_set_default(struct ieee80211_if_sta *sta)
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{
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u8 def_id[4] = {0x00, 0x0F, 0xAC, 0xff};
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memcpy(sta->mesh_pp_id, def_id, 4);
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memcpy(sta->mesh_pm_id, def_id, 4);
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memcpy(sta->mesh_cc_id, def_id, 4);
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}
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int mesh_rmc_init(struct net_device *dev)
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{
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struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
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int i;
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sdata->u.sta.rmc = kmalloc(sizeof(struct mesh_rmc), GFP_KERNEL);
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if (!sdata->u.sta.rmc)
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return -ENOMEM;
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sdata->u.sta.rmc->idx_mask = RMC_BUCKETS - 1;
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for (i = 0; i < RMC_BUCKETS; i++)
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INIT_LIST_HEAD(&sdata->u.sta.rmc->bucket[i].list);
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return 0;
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}
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void mesh_rmc_free(struct net_device *dev)
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{
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struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
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struct mesh_rmc *rmc = sdata->u.sta.rmc;
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struct rmc_entry *p, *n;
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int i;
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if (!sdata->u.sta.rmc)
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return;
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for (i = 0; i < RMC_BUCKETS; i++)
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list_for_each_entry_safe(p, n, &rmc->bucket[i].list, list) {
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list_del(&p->list);
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kmem_cache_free(rm_cache, p);
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}
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kfree(rmc);
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sdata->u.sta.rmc = NULL;
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}
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/**
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* mesh_rmc_check - Check frame in recent multicast cache and add if absent.
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*
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* @sa: source address
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* @mesh_hdr: mesh_header
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*
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* Returns: 0 if the frame is not in the cache, nonzero otherwise.
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*
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* Checks using the source address and the mesh sequence number if we have
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* received this frame lately. If the frame is not in the cache, it is added to
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* it.
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*/
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int mesh_rmc_check(u8 *sa, struct ieee80211s_hdr *mesh_hdr,
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struct net_device *dev)
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{
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struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
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struct mesh_rmc *rmc = sdata->u.sta.rmc;
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u32 seqnum = 0;
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int entries = 0;
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u8 idx;
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struct rmc_entry *p, *n;
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/* Don't care about endianness since only match matters */
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memcpy(&seqnum, mesh_hdr->seqnum, sizeof(mesh_hdr->seqnum));
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idx = mesh_hdr->seqnum[0] & rmc->idx_mask;
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list_for_each_entry_safe(p, n, &rmc->bucket[idx].list, list) {
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++entries;
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if (time_after(jiffies, p->exp_time) ||
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(entries == RMC_QUEUE_MAX_LEN)) {
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list_del(&p->list);
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kmem_cache_free(rm_cache, p);
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--entries;
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} else if ((seqnum == p->seqnum)
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&& (memcmp(sa, p->sa, ETH_ALEN) == 0))
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return -1;
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}
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p = kmem_cache_alloc(rm_cache, GFP_ATOMIC);
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if (!p) {
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printk(KERN_DEBUG "o11s: could not allocate RMC entry\n");
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return 0;
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}
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p->seqnum = seqnum;
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p->exp_time = jiffies + RMC_TIMEOUT;
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memcpy(p->sa, sa, ETH_ALEN);
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list_add(&p->list, &rmc->bucket[idx].list);
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return 0;
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}
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void mesh_mgmt_ies_add(struct sk_buff *skb, struct net_device *dev)
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{
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struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
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struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
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struct ieee80211_supported_band *sband;
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u8 *pos;
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int len, i, rate;
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sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
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len = sband->n_bitrates;
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if (len > 8)
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len = 8;
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pos = skb_put(skb, len + 2);
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*pos++ = WLAN_EID_SUPP_RATES;
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*pos++ = len;
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for (i = 0; i < len; i++) {
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rate = sband->bitrates[i].bitrate;
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*pos++ = (u8) (rate / 5);
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}
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if (sband->n_bitrates > len) {
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pos = skb_put(skb, sband->n_bitrates - len + 2);
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*pos++ = WLAN_EID_EXT_SUPP_RATES;
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*pos++ = sband->n_bitrates - len;
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for (i = len; i < sband->n_bitrates; i++) {
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rate = sband->bitrates[i].bitrate;
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*pos++ = (u8) (rate / 5);
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}
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}
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pos = skb_put(skb, 2 + sdata->u.sta.mesh_id_len);
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*pos++ = WLAN_EID_MESH_ID;
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*pos++ = sdata->u.sta.mesh_id_len;
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if (sdata->u.sta.mesh_id_len)
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memcpy(pos, sdata->u.sta.mesh_id, sdata->u.sta.mesh_id_len);
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pos = skb_put(skb, 21);
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*pos++ = WLAN_EID_MESH_CONFIG;
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*pos++ = MESH_CFG_LEN;
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/* Version */
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*pos++ = 1;
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/* Active path selection protocol ID */
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memcpy(pos, sdata->u.sta.mesh_pp_id, 4);
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pos += 4;
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/* Active path selection metric ID */
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memcpy(pos, sdata->u.sta.mesh_pm_id, 4);
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pos += 4;
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/* Congestion control mode identifier */
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memcpy(pos, sdata->u.sta.mesh_cc_id, 4);
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pos += 4;
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/* Channel precedence:
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* Not running simple channel unification protocol
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*/
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memset(pos, 0x00, 4);
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pos += 4;
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/* Mesh capability */
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sdata->u.sta.accepting_plinks = mesh_plink_availables(sdata);
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*pos++ = sdata->u.sta.accepting_plinks ? ACCEPT_PLINKS : 0x00;
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*pos++ = 0x00;
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return;
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}
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u32 mesh_table_hash(u8 *addr, struct net_device *dev, struct mesh_table *tbl)
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{
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/* Use last four bytes of hw addr and interface index as hash index */
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return jhash_2words(*(u32 *)(addr+2), dev->ifindex, tbl->hash_rnd)
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& tbl->hash_mask;
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}
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u8 mesh_id_hash(u8 *mesh_id, int mesh_id_len)
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{
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if (!mesh_id_len)
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return 1;
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else if (mesh_id_len == 1)
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return (u8) mesh_id[0];
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else
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return (u8) (mesh_id[0] + 2 * mesh_id[1]);
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}
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struct mesh_table *mesh_table_alloc(int size_order)
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{
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int i;
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struct mesh_table *newtbl;
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newtbl = kmalloc(sizeof(struct mesh_table), GFP_KERNEL);
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if (!newtbl)
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return NULL;
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newtbl->hash_buckets = kzalloc(sizeof(struct hlist_head) *
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(1 << size_order), GFP_KERNEL);
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if (!newtbl->hash_buckets) {
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kfree(newtbl);
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return NULL;
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}
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newtbl->hashwlock = kmalloc(sizeof(spinlock_t) *
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(1 << size_order), GFP_KERNEL);
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if (!newtbl->hashwlock) {
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kfree(newtbl->hash_buckets);
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kfree(newtbl);
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return NULL;
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}
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newtbl->size_order = size_order;
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newtbl->hash_mask = (1 << size_order) - 1;
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atomic_set(&newtbl->entries, 0);
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get_random_bytes(&newtbl->hash_rnd,
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sizeof(newtbl->hash_rnd));
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for (i = 0; i <= newtbl->hash_mask; i++)
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spin_lock_init(&newtbl->hashwlock[i]);
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return newtbl;
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}
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void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
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{
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struct hlist_head *mesh_hash;
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struct hlist_node *p, *q;
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int i;
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mesh_hash = tbl->hash_buckets;
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for (i = 0; i <= tbl->hash_mask; i++) {
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spin_lock(&tbl->hashwlock[i]);
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hlist_for_each_safe(p, q, &mesh_hash[i]) {
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tbl->free_node(p, free_leafs);
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atomic_dec(&tbl->entries);
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}
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spin_unlock(&tbl->hashwlock[i]);
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}
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kfree(tbl->hash_buckets);
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kfree(tbl->hashwlock);
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kfree(tbl);
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}
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static void ieee80211_mesh_path_timer(unsigned long data)
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{
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struct ieee80211_sub_if_data *sdata =
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(struct ieee80211_sub_if_data *) data;
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struct ieee80211_if_sta *ifsta = &sdata->u.sta;
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struct ieee80211_local *local = wdev_priv(&sdata->wdev);
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queue_work(local->hw.workqueue, &ifsta->work);
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}
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struct mesh_table *mesh_table_grow(struct mesh_table *tbl)
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{
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struct mesh_table *newtbl;
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struct hlist_head *oldhash;
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struct hlist_node *p;
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int err = 0;
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int i;
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if (atomic_read(&tbl->entries)
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< tbl->mean_chain_len * (tbl->hash_mask + 1)) {
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err = -EPERM;
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goto endgrow;
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}
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newtbl = mesh_table_alloc(tbl->size_order + 1);
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if (!newtbl) {
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err = -ENOMEM;
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goto endgrow;
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}
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newtbl->free_node = tbl->free_node;
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newtbl->mean_chain_len = tbl->mean_chain_len;
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newtbl->copy_node = tbl->copy_node;
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atomic_set(&newtbl->entries, atomic_read(&tbl->entries));
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oldhash = tbl->hash_buckets;
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for (i = 0; i <= tbl->hash_mask; i++)
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hlist_for_each(p, &oldhash[i])
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tbl->copy_node(p, newtbl);
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endgrow:
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if (err)
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return NULL;
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else
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return newtbl;
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}
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