cfg80211: simplify mesh BSS comparison

Instead of first checking if a BSS is an MBSS
and then doing the comparisons, inline it all
into the BSS comparison function. This avoids
doing the IE searches twice and is also a lot
less code.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 39 insertions, 81 deletions

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index d4fe065eeb11..1435b97b1ca2 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -288,26 +288,6 @@ const u8 *cfg80211_find_vendor_ie(unsigned int oui, u8 oui_type,
 }
 EXPORT_SYMBOL(cfg80211_find_vendor_ie);
 
-static int cmp_ies(u8 num, const u8 *ies1, int len1, const u8 *ies2, int len2)
-{
-        const u8 *ie1 = cfg80211_find_ie(num, ies1, len1);
-        const u8 *ie2 = cfg80211_find_ie(num, ies2, len2);
-
-        /* equal if both missing */
-        if (!ie1 && !ie2)
-                return 0;
-        /* sort missing IE before (left of) present IE */
-        if (!ie1)
-                return -1;
-        if (!ie2)
-                return 1;
-
-        /* sort by length first, then by contents */
-        if (ie1[1] != ie2[1])
-                return ie2[1] - ie1[1];
-        return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
-}
-
 static bool is_bss(struct cfg80211_bss *a, const u8 *bssid,
                    const u8 *ssid, size_t ssid_len)
 {
@@ -331,29 +311,6 @@ static bool is_bss(struct cfg80211_bss *a, const u8 *bssid,
         return memcmp(ssidie + 2, ssid, ssid_len) == 0;
 }
 
-static bool is_mesh_bss(struct cfg80211_bss *a)
-{
-        const struct cfg80211_bss_ies *ies;
-        const u8 *ie;
-
-        if (!WLAN_CAPABILITY_IS_STA_BSS(a->capability))
-                return false;
-
-        ies = rcu_access_pointer(a->ies);
-        if (!ies)
-                return false;
-
-        ie = cfg80211_find_ie(WLAN_EID_MESH_ID, ies->data, ies->len);
-        if (!ie)
-                return false;
-
-        ie = cfg80211_find_ie(WLAN_EID_MESH_CONFIG, ies->data, ies->len);
-        if (!ie)
-                return false;
-
-        return true;
-}
-
 static bool is_mesh(struct cfg80211_bss *a,
                     const u8 *meshid, size_t meshidlen,
                     const u8 *meshcfg)
@@ -391,39 +348,6 @@ static bool is_mesh(struct cfg80211_bss *a,
                       sizeof(struct ieee80211_meshconf_ie) - 2) == 0;
 }
 
-static int cmp_bss_core(struct cfg80211_bss *a, struct cfg80211_bss *b)
-{
-        const struct cfg80211_bss_ies *a_ies, *b_ies;
-        int r;
-
-        if (a->channel != b->channel)
-                return b->channel->center_freq - a->channel->center_freq;
-
-        if (is_mesh_bss(a) && is_mesh_bss(b)) {
-                a_ies = rcu_access_pointer(a->ies);
-                if (!a_ies)
-                        return -1;
-                b_ies = rcu_access_pointer(b->ies);
-                if (!b_ies)
-                        return 1;
-
-                r = cmp_ies(WLAN_EID_MESH_ID,
-                            a_ies->data, a_ies->len,
-                            b_ies->data, b_ies->len);
-                if (r)
-                        return r;
-                return cmp_ies(WLAN_EID_MESH_CONFIG,
-                               a_ies->data, a_ies->len,
-                               b_ies->data, b_ies->len);
-        }
-
-        /*
-         * we can't use compare_ether_addr here since we need a < > operator.
-         * The binary return value of compare_ether_addr isn't enough
-         */
-        return memcmp(a->bssid, b->bssid, sizeof(a->bssid));
-}
-
 /**
  * enum bss_compare_mode - BSS compare mode
  * @BSS_CMP_REGULAR: regular compare mode (for insertion and normal find)
@@ -441,13 +365,12 @@ static int cmp_bss(struct cfg80211_bss *a,
                    enum bss_compare_mode mode)
 {
         const struct cfg80211_bss_ies *a_ies, *b_ies;
-        const u8 *ie1;
-        const u8 *ie2;
+        const u8 *ie1 = NULL;
+        const u8 *ie2 = NULL;
         int i, r;
 
-        r = cmp_bss_core(a, b);
-        if (r)
-                return r;
+        if (a->channel != b->channel)
+                return b->channel->center_freq - a->channel->center_freq;
 
         a_ies = rcu_access_pointer(a->ies);
         if (!a_ies)
@@ -456,6 +379,41 @@ static int cmp_bss(struct cfg80211_bss *a,
         if (!b_ies)
                 return 1;
 
+        if (WLAN_CAPABILITY_IS_STA_BSS(a->capability))
+                ie1 = cfg80211_find_ie(WLAN_EID_MESH_ID,
+                                       a_ies->data, a_ies->len);
+        if (WLAN_CAPABILITY_IS_STA_BSS(b->capability))
+                ie2 = cfg80211_find_ie(WLAN_EID_MESH_ID,
+                                       b_ies->data, b_ies->len);
+        if (ie1 && ie2) {
+                int mesh_id_cmp;
+
+                if (ie1[1] == ie2[1])
+                        mesh_id_cmp = memcmp(ie1 + 2, ie2 + 2, ie1[1]);
+                else
+                        mesh_id_cmp = ie2[1] - ie1[1];
+
+                ie1 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
+                                       a_ies->data, a_ies->len);
+                ie2 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
+                                       b_ies->data, b_ies->len);
+                if (ie1 && ie2) {
+                        if (mesh_id_cmp)
+                                return mesh_id_cmp;
+                        if (ie1[1] != ie2[1])
+                                return ie2[1] - ie1[1];
+                        return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
+                }
+        }
+
+        /*
+         * we can't use compare_ether_addr here since we need a < > operator.
+         * The binary return value of compare_ether_addr isn't enough
+         */
+        r = memcmp(a->bssid, b->bssid, sizeof(a->bssid));
+        if (r)
+                return r;
+
         ie1 = cfg80211_find_ie(WLAN_EID_SSID, a_ies->data, a_ies->len);
         ie2 = cfg80211_find_ie(WLAN_EID_SSID, b_ies->data, b_ies->len);