mac80211: add generic cipher scheme support

This adds generic cipher scheme support to mac80211, such schemes
are fully under control by the driver. On hw registration drivers
may specify additional HW ciphers with a scheme how these ciphers
have to be handled by mac80211 TX/RR. A cipher scheme specifies a
cipher suite value, a size of the security header to be added to
or stripped from frames and how the PN is to be verified on RX.

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

1 files changed, 68 insertions, 0 deletions

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index fd4fe5d61782..5dfa41abdf8b 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2475,3 +2475,71 @@ int ieee80211_send_action_csa(struct ieee80211_sub_if_data *sdata,
 	ieee80211_tx_skb(sdata, skb);
 	return 0;
 }
+
+bool ieee80211_cs_valid(const struct ieee80211_cipher_scheme *cs)
+{
+	return !(cs == NULL || cs->cipher == 0 ||
+		 cs->hdr_len < cs->pn_len + cs->pn_off ||
+		 cs->hdr_len <= cs->key_idx_off ||
+		 cs->key_idx_shift > 7 ||
+		 cs->key_idx_mask == 0);
+}
+
+bool ieee80211_cs_list_valid(const struct ieee80211_cipher_scheme *cs, int n)
+{
+	int i;
+
+	/* Ensure we have enough iftype bitmap space for all iftype values */
+	WARN_ON((NUM_NL80211_IFTYPES / 8 + 1) > sizeof(cs[0].iftype));
+
+	for (i = 0; i < n; i++)
+		if (!ieee80211_cs_valid(&cs[i]))
+			return false;
+
+	return true;
+}
+
+const struct ieee80211_cipher_scheme *
+ieee80211_cs_get(struct ieee80211_local *local, u32 cipher,
+		 enum nl80211_iftype iftype)
+{
+	const struct ieee80211_cipher_scheme *l = local->hw.cipher_schemes;
+	int n = local->hw.n_cipher_schemes;
+	int i;
+	const struct ieee80211_cipher_scheme *cs = NULL;
+
+	for (i = 0; i < n; i++) {
+		if (l[i].cipher == cipher) {
+			cs = &l[i];
+			break;
+		}
+	}
+
+	if (!cs || !(cs->iftype & BIT(iftype)))
+		return NULL;
+
+	return cs;
+}
+
+int ieee80211_cs_headroom(struct ieee80211_local *local,
+			  struct cfg80211_crypto_settings *crypto,
+			  enum nl80211_iftype iftype)
+{
+	const struct ieee80211_cipher_scheme *cs;
+	int headroom = IEEE80211_ENCRYPT_HEADROOM;
+	int i;
+
+	for (i = 0; i < crypto->n_ciphers_pairwise; i++) {
+		cs = ieee80211_cs_get(local, crypto->ciphers_pairwise[i],
+				      iftype);
+
+		if (cs && headroom < cs->hdr_len)
+			headroom = cs->hdr_len;
+	}
+
+	cs = ieee80211_cs_get(local, crypto->cipher_group, iftype);
+	if (cs && headroom < cs->hdr_len)
+		headroom = cs->hdr_len;
+
+	return headroom;
+}