mac80211: extend fast-xmit for more ciphers
When crypto is offloaded then in some cases it's all handled
by the device, and in others only some space for the IV must
be reserved in the frame. Handle both of these cases in the
fast-xmit path, up to a limit of 18 bytes of space for IVs.
Change-Id: I9987f7e467e6ea238cdd7d623462044e1db4005d
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 503ad8a..34b875e 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -241,6 +241,8 @@
/* Value to indicate no TID reservation */
#define IEEE80211_TID_UNRESERVED 0xff
+#define IEEE80211_FAST_XMIT_MAX_IV 18
+
/**
* struct ieee80211_fast_tx - TX fastpath information
* @key: key to use for hw crypto
@@ -252,17 +254,20 @@
* @band: band this will be transmitted on, for tx_info
* @rcu_head: RCU head to free this struct
*
- * Try to keep this struct small so it fits into a single cacheline.
+ * This struct is small enough so that the common case (maximum crypto
+ * header length of 8 like for CCMP/GCMP) fits into a single 64-byte
+ * cache line. Moved rcu_head after key to prevent the compiler from
+ * adding padding.
+ *
*/
struct ieee80211_fast_tx {
struct ieee80211_key *key;
- u8 hdr[30 + 2 + IEEE80211_CCMP_HDR_LEN +
- sizeof(rfc1042_header)];
+ struct rcu_head rcu_head;
u8 hdr_len;
u8 sa_offs, da_offs, pn_offs;
u8 band;
-
- struct rcu_head rcu_head;
+ u8 hdr[30 + 2 + IEEE80211_FAST_XMIT_MAX_IV +
+ sizeof(rfc1042_header)];
};
/**
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 8618c21..289d323 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -2535,10 +2535,11 @@
if (!build.key)
build.key = rcu_access_pointer(sdata->default_unicast_key);
if (build.key) {
- bool gen_iv, iv_spc;
+ bool gen_iv, iv_spc, mmic;
gen_iv = build.key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV;
iv_spc = build.key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE;
+ mmic = build.key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC;
/* don't handle software crypto */
if (!(build.key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
@@ -2567,9 +2568,42 @@
if (gen_iv || iv_spc)
build.hdr_len += IEEE80211_GCMP_HDR_LEN;
break;
- default:
- /* don't do fast-xmit for these ciphers (yet) */
+ case WLAN_CIPHER_SUITE_TKIP:
+ /* cannot handle MMIC or IV generation in xmit-fast */
+ if (mmic || gen_iv)
+ goto out;
+ if (iv_spc)
+ build.hdr_len += IEEE80211_TKIP_IV_LEN;
+ break;
+ case WLAN_CIPHER_SUITE_WEP40:
+ case WLAN_CIPHER_SUITE_WEP104:
+ /* cannot handle IV generation in fast-xmit */
+ if (gen_iv)
+ goto out;
+ if (iv_spc)
+ build.hdr_len += IEEE80211_WEP_IV_LEN;
+ break;
+ case WLAN_CIPHER_SUITE_AES_CMAC:
+ case WLAN_CIPHER_SUITE_BIP_CMAC_256:
+ case WLAN_CIPHER_SUITE_BIP_GMAC_128:
+ case WLAN_CIPHER_SUITE_BIP_GMAC_256:
+ WARN(1,
+ "management cipher suite 0x%x enabled for data\n",
+ build.key->conf.cipher);
goto out;
+ default:
+ /* we don't know how to generate IVs for this at all */
+ if (WARN_ON(gen_iv))
+ goto out;
+ /* pure hardware keys are OK, of course */
+ if (!(build.key->flags & KEY_FLAG_CIPHER_SCHEME))
+ break;
+ /* cipher scheme might require space allocation */
+ if (iv_spc &&
+ build.key->conf.iv_len > IEEE80211_FAST_XMIT_MAX_IV)
+ goto out;
+ if (iv_spc)
+ build.hdr_len += build.key->conf.iv_len;
}
fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
