When processing an ADDBA request, iwm(4) runs a task which sends a

command to the firmware and waits for confirmation. This command can
fail and there was no way we could recover from such an error.

Allow drivers to return EBUSY from their ic_ampdu_rx_start() handler to
tell the stack not to send a confirmation just yet. The stack provides
functions which the driver can call to accept or refuse the request.

There is no functional change yet. This just shuffles code around so
drivers may insert themselves into the process.

ok mpi@

1 files changed, 60 insertions, 28 deletions

diff --git a/sys/net80211/ieee80211_input.c b/sys/net80211/ieee80211_input.c
index 66c03fade59..f57cdbdbc4c 100644
--- a/sys/net80211/ieee80211_input.c
+++ b/sys/net80211/ieee80211_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ieee80211_input.c,v 1.179 2016/09/20 13:24:42 stsp Exp $	*/
+/*	$OpenBSD: ieee80211_input.c,v 1.180 2016/09/21 12:21:27 stsp Exp $	*/
 
 /*-
  * Copyright (c) 2001 Atsushi Onoe
@@ -2424,8 +2424,9 @@ ieee80211_recv_addba_req(struct ieee80211com *ic, struct mbuf *m,
 	const struct ieee80211_frame *wh;
 	const u_int8_t *frm;
 	struct ieee80211_rx_ba *ba;
-	u_int16_t params, ssn, bufsz, timeout, status;
+	u_int16_t params, ssn, bufsz, timeout;
 	u_int8_t token, tid;
+	int err;
 
 	if (!(ni->ni_flags & IEEE80211_NODE_HT)) {
 		DPRINTF(("received ADDBA req from non-HT STA %s\n",
@@ -2467,32 +2468,33 @@ ieee80211_recv_addba_req(struct ieee80211com *ic, struct mbuf *m,
 			ieee80211_ba_move_window(ic, ni, tid, ssn);
 		return;
 	}
+
+	/* If the driver does not support A-MPDU, refuse the request. */
+	if (ic->ic_ampdu_rx_start == NULL)
+		goto refuse;
+
 	/* if PBAC required but RA does not support it, refuse request */
 	if ((ic->ic_flags & IEEE80211_F_PBAR) &&
 	    (!(ni->ni_flags & IEEE80211_NODE_MFP) ||
-	     !(ni->ni_rsncaps & IEEE80211_RSNCAP_PBAC))) {
-		status = IEEE80211_STATUS_REFUSED;
-		goto resp;
-	}
+	     !(ni->ni_rsncaps & IEEE80211_RSNCAP_PBAC)))
+		goto refuse;
 	/*
 	 * If the TID for which the Block Ack agreement is requested is
 	 * configured with a no-ACK policy, refuse the agreement.
 	 */
-	if (ic->ic_tid_noack & (1 << tid)) {
-		status = IEEE80211_STATUS_REFUSED;
-		goto resp;
-	}
+	if (ic->ic_tid_noack & (1 << tid))
+		goto refuse;
+
 	/* check that we support the requested Block Ack Policy */
 	if (!(ic->ic_htcaps & IEEE80211_HTCAP_DELAYEDBA) &&
-	    !(params & IEEE80211_ADDBA_BA_POLICY)) {
-		status = IEEE80211_STATUS_INVALID_PARAM;
-		goto resp;
-	}
+	    !(params & IEEE80211_ADDBA_BA_POLICY))
+		goto refuse;
 
 	/* setup Block Ack agreement */
 	ba->ba_state = IEEE80211_BA_INIT;
 	ba->ba_timeout_val = timeout * IEEE80211_DUR_TU;
 	ba->ba_ni = ni;
+	ba->ba_token = token;
 	timeout_set(&ba->ba_to, ieee80211_rx_ba_timeout, ba);
 	timeout_set(&ba->ba_gap_to, ieee80211_input_ba_gap_timeout, ba);
 	ba->ba_winsize = bufsz;
@@ -2506,31 +2508,61 @@ ieee80211_recv_addba_req(struct ieee80211com *ic, struct mbuf *m,
 	/* allocate and setup our reordering buffer */
 	ba->ba_buf = malloc(IEEE80211_BA_MAX_WINSZ * sizeof(*ba->ba_buf),
 	    M_DEVBUF, M_NOWAIT | M_ZERO);
-	if (ba->ba_buf == NULL) {
-		status = IEEE80211_STATUS_REFUSED;
-		goto resp;
-	}
+	if (ba->ba_buf == NULL)
+		goto refuse;
+
 	ba->ba_head = 0;
 
 	/* notify drivers of this new Block Ack agreement */
-	if (ic->ic_ampdu_rx_start == NULL ||
-	    ic->ic_ampdu_rx_start(ic, ni, tid) != 0) {
+	err = ic->ic_ampdu_rx_start(ic, ni, tid);
+	if (err == EBUSY) {
+		/* driver will accept or refuse agreement when done */
+		return;
+	} else if (err) {
 		/* driver failed to setup, rollback */
-		free(ba->ba_buf, M_DEVBUF, 0);
-		ba->ba_buf = NULL;
-		status = IEEE80211_STATUS_REFUSED;
-		goto resp;
-	}
+		ieee80211_addba_req_refuse(ic, ni, tid);
+	} else
+		ieee80211_addba_req_accept(ic, ni, tid);
+	return;
+
+ refuse:
+	/* MLME-ADDBA.response */
+	IEEE80211_SEND_ACTION(ic, ni, IEEE80211_CATEG_BA,
+	    IEEE80211_ACTION_ADDBA_RESP,
+	    IEEE80211_STATUS_REFUSED << 16 | token << 8 | tid);
+}
+
+void
+ieee80211_addba_req_accept(struct ieee80211com *ic, struct ieee80211_node *ni,
+    uint8_t tid)
+{
+	struct ieee80211_rx_ba *ba = &ni->ni_rx_ba[tid];
+
 	ba->ba_state = IEEE80211_BA_AGREED;
 	ic->ic_stats.is_ht_rx_ba_agreements++;
 	/* start Block Ack inactivity timer */
 	if (ba->ba_timeout_val != 0)
 		timeout_add_usec(&ba->ba_to, ba->ba_timeout_val);
-	status = IEEE80211_STATUS_SUCCESS;
- resp:
+
+	/* MLME-ADDBA.response */
+	IEEE80211_SEND_ACTION(ic, ni, IEEE80211_CATEG_BA,
+	    IEEE80211_ACTION_ADDBA_RESP,
+	    IEEE80211_STATUS_SUCCESS << 16 | ba->ba_token << 8 | tid);
+}
+
+void
+ieee80211_addba_req_refuse(struct ieee80211com *ic, struct ieee80211_node *ni,
+    uint8_t tid)
+{
+	struct ieee80211_rx_ba *ba = &ni->ni_rx_ba[tid];
+
+	free(ba->ba_buf, M_DEVBUF, 0);
+	ba->ba_buf = NULL;
+
 	/* MLME-ADDBA.response */
 	IEEE80211_SEND_ACTION(ic, ni, IEEE80211_CATEG_BA,
-	    IEEE80211_ACTION_ADDBA_RESP, status << 16 | token << 8 | tid);
+	    IEEE80211_ACTION_ADDBA_RESP,
+	    IEEE80211_STATUS_REFUSED << 16 | ba->ba_token << 8 | tid);
 }
 
 /*-