[PATCH] hostapd: Modified algorithm for generating BSSIDs

[Bill Jordan]

Modified algorithm for generating BSSIDs. Always set locally
administered bit. Calculate the mask after calculating the
BSSIDs. This eliminates the "Invalid BSSID mask" caused when
addr & mask != addr.

Signed-off-by: Bill Jordan <bjordan at rajant.com>
---
 src/ap/hostapd.c |   74 ++++++------------------------------------------------
 1 files changed, 8 insertions(+), 66 deletions(-)

diff --git a/src/ap/hostapd.c b/src/ap/hostapd.c
index f4517f8..1dc6b66 100644
--- a/src/ap/hostapd.c
+++ b/src/ap/hostapd.c
@@ -360,70 +360,26 @@ static int hostapd_validate_bssid_configuration(struct hostapd_iface *iface)
 {
 	u8 mask[ETH_ALEN] = { 0 };
 	struct hostapd_data *hapd = iface->bss[0];
-	unsigned int i = iface->conf->num_bss, bits = 0, j;
+	unsigned int i, j;
 	int res;
-	int auto_addr = 0;
 
 	if (hostapd_drv_none(hapd))
 		return 0;
 
 	/* Generate BSSID mask that is large enough to cover the BSSIDs. */
 
-	/* Determine the bits necessary to cover the number of BSSIDs. */
-	for (i--; i; i >>= 1)
-		bits++;
-
 	/* Determine the bits necessary to any configured BSSIDs,
 	   if they are higher than the number of BSSIDs. */
 	for (j = 0; j < iface->conf->num_bss; j++) {
-		if (hostapd_mac_comp_empty(iface->conf->bss[j].bssid) == 0) {
-			if (j)
-				auto_addr++;
-			continue;
-		}
-
 		for (i = 0; i < ETH_ALEN; i++) {
 			mask[i] |=
-				iface->conf->bss[j].bssid[i] ^
+				iface->bss[j]->conf->bssid[i] ^
 				hapd->own_addr[i];
 		}
 	}
 
-	if (!auto_addr)
-		goto skip_mask_ext;
-
-	for (i = 0; i < ETH_ALEN && mask[i] == 0; i++)
-		;
-	j = 0;
-	if (i < ETH_ALEN) {
-		j = (5 - i) * 8;
-
-		while (mask[i] != 0) {
-			mask[i] >>= 1;
-			j++;
-		}
-	}
-
-	if (bits < j)
-		bits = j;
-
-	if (bits > 40) {
-		wpa_printf(MSG_ERROR, "Too many bits in the BSSID mask (%u)",
-			   bits);
-		return -1;
-	}
-
-	os_memset(mask, 0xff, ETH_ALEN);
-	j = bits / 8;
-	for (i = 5; i > 5 - j; i--)
-		mask[i] = 0;
-	j = bits % 8;
-	while (j--)
-		mask[i] <<= 1;
-
-skip_mask_ext:
-	wpa_printf(MSG_DEBUG, "BSS count %lu, BSSID mask " MACSTR " (%d bits)",
-		   (unsigned long) iface->conf->num_bss, MAC2STR(mask), bits);
+	wpa_printf(MSG_DEBUG, "BSS count %lu, BSSID mask " MACSTR ,
+		   (unsigned long) iface->conf->num_bss, MAC2STR(mask));
 
 	res = hostapd_valid_bss_mask(hapd, hapd->own_addr, mask);
 	if (res == 0)
@@ -436,21 +392,6 @@ skip_mask_ext:
 		return -1;
 	}
 
-	if (!auto_addr)
-		return 0;
-
-	for (i = 0; i < ETH_ALEN; i++) {
-		if ((hapd->own_addr[i] & mask[i]) != hapd->own_addr[i]) {
-			wpa_printf(MSG_ERROR, "Invalid BSSID mask " MACSTR
-				   " for start address " MACSTR ".",
-				   MAC2STR(mask), MAC2STR(hapd->own_addr));
-			wpa_printf(MSG_ERROR, "Start address must be the "
-				   "first address in the block (i.e., addr "
-				   "AND mask == addr).");
-			return -1;
-		}
-	}
-
 	return 0;
 }
 
@@ -492,6 +433,7 @@ static int hostapd_setup_bss(struct hostapd_data *hapd, int first)
 	if (!first) {
 		if (hostapd_mac_comp_empty(hapd->conf->bssid) == 0) {
 			/* Allocate the next available BSSID. */
+			hapd->own_addr[0] |= 2; /* locally administered address */
 			do {
 				inc_byte_array(hapd->own_addr, ETH_ALEN);
 			} while (mac_in_conf(hapd->iconf, hapd->own_addr));
@@ -672,9 +614,6 @@ static int setup_interface(struct hostapd_iface *iface)
 		iface->bss[i]->drv_priv = hapd->drv_priv;
 	}
 
-	if (hostapd_validate_bssid_configuration(iface))
-		return -1;
-
 	if (hapd->iconf->country[0] && hapd->iconf->country[1]) {
 		os_memcpy(country, hapd->iconf->country, 3);
 		country[3] = '\0';
@@ -774,6 +713,9 @@ int hostapd_setup_interface_complete(struct hostapd_iface *iface, int err)
 			prev_addr = hapd->own_addr;
 	}
 
+	if (hostapd_validate_bssid_configuration(iface))
+		return -1;
+
 	hostapd_tx_queue_params(iface);
 
 	ap_list_init(iface);
-- 
1.7.2.3