Return-path: Received: from mail30f.wh2.ocn.ne.jp ([220.111.41.203]:43892 "HELO mail30f.wh2.ocn.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753230AbYBFC7m (ORCPT ); Tue, 5 Feb 2008 21:59:42 -0500 From: bruno randolf To: ath5k-devel@lists.ath5k.org Subject: Re: [ath5k-devel] [PATCH] addressing johannes latest comments and adding a =?iso-8859-1?q?channel=09check=2E=2E=2E?= Date: Wed, 6 Feb 2008 11:59:34 +0900 Cc: jirislaby@gmail.com, flamingice@sourmilk.net, linux-wireless@vger.kernel.org, linville@tuxdriver.com, jbenc@suse.cz, johannes@sipsolutions.net References: <1202209693.4395.29.camel@johannes.berg> <20080206024640.22750.72748.stgit@one> In-Reply-To: <20080206024640.22750.72748.stgit@one> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Message-Id: <200802061159.34728.bruno@thinktube.com> (sfid-20080206_025947_207856_491B27FC) Sender: linux-wireless-owner@vger.kernel.org List-ID: uups, sorry stg mail (well, i...) confused the subject lines bruno On Wednesday 06 February 2008 11:46:40 Bruno Randolf wrote: > mac80211: enable IBSS merging > > enable IBSS cell merging. if an IBSS beacon with the same channel, same > ESSID and a TSF higher than the local TSF (mactime) is received, we have to > join its BSSID. while this might not be immediately apparent from reading > the 802.11 standard it is compliant and necessary to make IBSS mode > functional in many cases. most drivers have a similar behaviour. > > * move the relevant code section (previously only containing debug code) > down to the end of the function, so we can reuse the bss structure. > > * we have to compare the mactime (TSF at the time of packet receive) rather > than the current TSF. since some drivers are not able to give a reliable > mactime we fall back to use the current TSF, which will be enough to catch > most (but not all) cases where an IBSS merge is necessary. > > * in IBSS mode we want to allow beacons to override probe response info so > we can correctly do merges. > > * we don't only configure beacons based on scan results, so change that > message. > > * to enable this we have to let all beacons thru in IBSS mode, even if they > have a different BSSID. > > Signed-off-by: Bruno Randolf > --- > > include/net/mac80211.h | 3 +- > net/mac80211/ieee80211_sta.c | 70 > ++++++++++++++++++++++++++---------------- net/mac80211/rx.c | > 5 ++- > 3 files changed, 49 insertions(+), 29 deletions(-) > > > diff --git a/include/net/mac80211.h b/include/net/mac80211.h > index 460da54..4ae3a12 100644 > --- a/include/net/mac80211.h > +++ b/include/net/mac80211.h > @@ -276,7 +276,8 @@ struct ieee80211_tx_control { > * @RX_FLAG_FAILED_PLCP_CRC: Set this flag if the PCLP check failed on > * the frame. > * @RX_FLAG_TSFT: The timestamp passed in the RX status (@mactime field) > - * is valid. > + * is valid. This is useful in monitor mode and necessary for beacon > frames + * to enable IBSS merging. > */ > enum mac80211_rx_flags { > RX_FLAG_MMIC_ERROR = 1<<0, > diff --git a/net/mac80211/ieee80211_sta.c b/net/mac80211/ieee80211_sta.c > index 08f89fa..4df18ae 100644 > --- a/net/mac80211/ieee80211_sta.c > +++ b/net/mac80211/ieee80211_sta.c > @@ -2202,7 +2202,7 @@ static void ieee80211_rx_bss_info(struct net_device > *dev, struct ieee80211_sta_bss *bss; > struct sta_info *sta; > struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev); > - u64 timestamp; > + u64 timestamp, mactime; > DECLARE_MAC_BUF(mac); > DECLARE_MAC_BUF(mac2); > > @@ -2220,30 +2220,6 @@ static void ieee80211_rx_bss_info(struct net_device > *dev, return; > > timestamp = le64_to_cpu(mgmt->u.beacon.timestamp); > - > - if (sdata->vif.type == IEEE80211_IF_TYPE_IBSS && beacon && > - memcmp(mgmt->bssid, sdata->u.sta.bssid, ETH_ALEN) == 0) { > -#ifdef CONFIG_MAC80211_IBSS_DEBUG > - static unsigned long last_tsf_debug = 0; > - u64 tsf; > - if (local->ops->get_tsf) > - tsf = local->ops->get_tsf(local_to_hw(local)); > - else > - tsf = -1LLU; > - if (time_after(jiffies, last_tsf_debug + 5 * HZ)) { > - printk(KERN_DEBUG "RX beacon SA=%s BSSID=" > - "%s TSF=0x%llx BCN=0x%llx diff=%lld " > - "@%lu\n", > - print_mac(mac, mgmt->sa), print_mac(mac2, mgmt->bssid), > - (unsigned long long)tsf, > - (unsigned long long)timestamp, > - (unsigned long long)(tsf - timestamp), > - jiffies); > - last_tsf_debug = jiffies; > - } > -#endif /* CONFIG_MAC80211_IBSS_DEBUG */ > - } > - > ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen, &elems); > > if (sdata->vif.type == IEEE80211_IF_TYPE_IBSS && elems.supp_rates && > @@ -2329,8 +2305,10 @@ static void ieee80211_rx_bss_info(struct net_device > *dev, > > bss->band = rx_status->band; > > - if (bss->probe_resp && beacon) { > - /* Do not allow beacon to override data from Probe Response. */ > + if (sdata->vif.type != IEEE80211_IF_TYPE_IBSS && > + bss->probe_resp && beacon) { > + /* STA mode: > + * Do not allow beacon to override data from Probe Response. */ > ieee80211_rx_bss_put(dev, bss); > return; > } > @@ -2434,6 +2412,44 @@ static void ieee80211_rx_bss_info(struct net_device > *dev, bss->noise = rx_status->noise; > if (!beacon) > bss->probe_resp++; > + > + /* check if we need to merge IBSS */ > + if (sdata->vif.type == IEEE80211_IF_TYPE_IBSS && beacon && > + !local->sta_sw_scanning && !local->sta_hw_scanning && > + mgmt->u.beacon.capab_info & WLAN_CAPABILITY_IBSS && > + bss->freq == local->oper_channel->center_freq && > + elems.ssid_len == sdata->u.sta.ssid_len && > + memcmp(elems.ssid, sdata->u.sta.ssid, sdata->u.sta.ssid_len) == 0) { > + if (rx_status->flag & RX_FLAG_TSFT) > + /* in order for correct IBSS merging we need mactime */ > + mactime = rx_status->mactime; > + else if (local && local->ops && local->ops->get_tsf) > + /* second best option: get current TSF */ > + mactime = local->ops->get_tsf(local_to_hw(local)); > + else > + /* can't merge without knowing the TSF */ > + mactime = -1LLU; > +#ifdef CONFIG_MAC80211_IBSS_DEBUG > + printk(KERN_DEBUG "RX beacon SA=%s BSSID=" > + "%s TSF=0x%llx BCN=0x%llx diff=%lld @%lu\n", > + print_mac(mac, mgmt->sa), > + print_mac(mac2, mgmt->bssid), > + (unsigned long long)mactime, > + (unsigned long long)timestamp, > + (unsigned long long)(mactime - timestamp), > + jiffies); > +#endif /* CONFIG_MAC80211_IBSS_DEBUG */ > + if (mactime <= timestamp) { > + if (CONFIG_MAC80211_IBSS_DEBUG || net_ratelimit()) > + printk(KERN_DEBUG "%s: beacon TSF higher than " > + "local TSF - IBSS merge with BSSID %s\n", > + dev->name, print_mac(mac, mgmt->bssid)); > + ieee80211_sta_join_ibss(dev, &sdata->u.sta, bss); > + ieee80211_ibss_add_sta(dev, NULL, > + mgmt->bssid, mgmt->sa); > + } > + } > + > ieee80211_rx_bss_put(dev, bss); > } > > diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c > index beda1bf..ed7cf37 100644 > --- a/net/mac80211/rx.c > +++ b/net/mac80211/rx.c > @@ -1612,7 +1612,10 @@ static int prepare_for_handlers(struct > ieee80211_sub_if_data *sdata, case IEEE80211_IF_TYPE_IBSS: > if (!bssid) > return 0; > - if (!ieee80211_bssid_match(bssid, sdata->u.sta.bssid)) { > + if ((rx->fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_MGMT && > + (rx->fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_BEACON) > + return 1; > + else if (!ieee80211_bssid_match(bssid, sdata->u.sta.bssid)) { > if (!(rx->flags & IEEE80211_TXRXD_RXIN_SCAN)) > return 0; > rx->flags &= ~IEEE80211_TXRXD_RXRA_MATCH; > > _______________________________________________ > ath5k-devel mailing list > ath5k-devel@lists.ath5k.org > https://lists.ath5k.org/mailman/listinfo/ath5k-devel