From 8e664fb3fd2b04e3ac5fad7f046000ba54e0e275 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 23 Dec 2009 13:15:38 +0100 Subject: mac80211: split up and insert custom IEs correctly Currently, we insert all user-specified IEs before the HT IE for association, and after the HT IE for probe requests. For association, that's correct only if the user-specified IEs are RSN only, incorrect in all other cases including WPA. Change this to split apart the user-specified IEs in two places for association: before the HT IE (e.g. RSN), after the HT IE (generally empty right now I think?) and after WMM (all other vendor-specific IEs). For probes, split the IEs in different places to be correct according to the spec. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/mac80211/util.c | 134 ++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 114 insertions(+), 20 deletions(-) (limited to 'net/mac80211/util.c') diff --git a/net/mac80211/util.c b/net/mac80211/util.c index 5ffe9e831b66..1fdb80ff9241 100644 --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -881,30 +881,66 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer, enum ieee80211_band band) { struct ieee80211_supported_band *sband; - u8 *pos, *supp_rates_len, *esupp_rates_len = NULL; - int i; + u8 *pos; + size_t offset = 0, noffset; + int supp_rates_len, i; sband = local->hw.wiphy->bands[band]; pos = buffer; + supp_rates_len = min_t(int, sband->n_bitrates, 8); + *pos++ = WLAN_EID_SUPP_RATES; - supp_rates_len = pos; - *pos++ = 0; - - for (i = 0; i < sband->n_bitrates; i++) { - struct ieee80211_rate *rate = &sband->bitrates[i]; - - if (esupp_rates_len) { - *esupp_rates_len += 1; - } else if (*supp_rates_len == 8) { - *pos++ = WLAN_EID_EXT_SUPP_RATES; - esupp_rates_len = pos; - *pos++ = 1; - } else - *supp_rates_len += 1; + *pos++ = supp_rates_len; - *pos++ = rate->bitrate / 5; + for (i = 0; i < supp_rates_len; i++) { + int rate = sband->bitrates[i].bitrate; + *pos++ = (u8) (rate / 5); + } + + /* insert "request information" if in custom IEs */ + if (ie && ie_len) { + static const u8 before_extrates[] = { + WLAN_EID_SSID, + WLAN_EID_SUPP_RATES, + WLAN_EID_REQUEST, + }; + noffset = ieee80211_ie_split(ie, ie_len, + before_extrates, + ARRAY_SIZE(before_extrates), + offset); + memcpy(pos, ie + offset, noffset - offset); + pos += noffset - offset; + offset = noffset; + } + + if (sband->n_bitrates > i) { + *pos++ = WLAN_EID_EXT_SUPP_RATES; + *pos++ = sband->n_bitrates - i; + + for (; i < sband->n_bitrates; i++) { + int rate = sband->bitrates[i].bitrate; + *pos++ = (u8) (rate / 5); + } + } + + /* insert custom IEs that go before HT */ + if (ie && ie_len) { + static const u8 before_ht[] = { + WLAN_EID_SSID, + WLAN_EID_SUPP_RATES, + WLAN_EID_REQUEST, + WLAN_EID_EXT_SUPP_RATES, + WLAN_EID_DS_PARAMS, + WLAN_EID_SUPPORTED_REGULATORY_CLASSES, + }; + noffset = ieee80211_ie_split(ie, ie_len, + before_ht, ARRAY_SIZE(before_ht), + offset); + memcpy(pos, ie + offset, noffset - offset); + pos += noffset - offset; + offset = noffset; } if (sband->ht_cap.ht_supported) { @@ -936,9 +972,11 @@ int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer, * that calculates local->scan_ies_len. */ - if (ie) { - memcpy(pos, ie, ie_len); - pos += ie_len; + /* add any remaining custom IEs */ + if (ie && ie_len) { + noffset = ie_len; + memcpy(pos, ie + offset, noffset - offset); + pos += noffset - offset; } return pos - buffer; @@ -1252,3 +1290,59 @@ void ieee80211_recalc_smps(struct ieee80211_local *local, /* changed flag is auto-detected for this */ ieee80211_hw_config(local, 0); } + +static bool ieee80211_id_in_list(const u8 *ids, int n_ids, u8 id) +{ + int i; + + for (i = 0; i < n_ids; i++) + if (ids[i] == id) + return true; + return false; +} + +/** + * ieee80211_ie_split - split an IE buffer according to ordering + * + * @ies: the IE buffer + * @ielen: the length of the IE buffer + * @ids: an array with element IDs that are allowed before + * the split + * @n_ids: the size of the element ID array + * @offset: offset where to start splitting in the buffer + * + * This function splits an IE buffer by updating the @offset + * variable to point to the location where the buffer should be + * split. + * + * It assumes that the given IE buffer is well-formed, this + * has to be guaranteed by the caller! + * + * It also assumes that the IEs in the buffer are ordered + * correctly, if not the result of using this function will not + * be ordered correctly either, i.e. it does no reordering. + * + * The function returns the offset where the next part of the + * buffer starts, which may be @ielen if the entire (remainder) + * of the buffer should be used. + */ +size_t ieee80211_ie_split(const u8 *ies, size_t ielen, + const u8 *ids, int n_ids, size_t offset) +{ + size_t pos = offset; + + while (pos < ielen && ieee80211_id_in_list(ids, n_ids, ies[pos])) + pos += 2 + ies[pos + 1]; + + return pos; +} + +size_t ieee80211_ie_split_vendor(const u8 *ies, size_t ielen, size_t offset) +{ + size_t pos = offset; + + while (pos < ielen && ies[pos] != WLAN_EID_VENDOR_SPECIFIC) + pos += 2 + ies[pos + 1]; + + return pos; +} -- cgit v1.2.3