Change input handling to not expect drivers to filter short frames.

In particular, let drivers send up control frames so we can dispatch
them to bpf in monitor mode.

This is the first (small) step to adding more functionality such as
power save mode.

1 files changed, 24 insertions, 6 deletions

diff --git a/sys/net80211/ieee80211_input.c b/sys/net80211/ieee80211_input.c
index 003b425..4b5ec93 100644
--- a/sys/net80211/ieee80211_input.c
+++ b/sys/net80211/ieee80211_input.c
@@ -85,17 +85,26 @@ ieee80211_input(struct ifnet *ifp, struct mbuf *m, struct ieee80211_node *ni,
 	struct ether_header *eh;
 	struct mbuf *m1;
 	int len;
-	u_int8_t dir, subtype;
+	u_int8_t dir, type, subtype;
 	u_int8_t *bssid;
 	u_int16_t rxseq;
 
 	KASSERT(ni != NULL, ("null node"));
 
-	/* trim CRC here for WEP can find its own CRC at the end of packet. */
+	/* trim CRC here so WEP can find its own CRC at the end of packet. */
 	if (m->m_flags & M_HASFCS) {
 		m_adj(m, -IEEE80211_CRC_LEN);
 		m->m_flags &= ~M_HASFCS;
 	}
+	KASSERT(m->m_pkthdr.len >= sizeof(struct ieee80211_frame_min),
+		("frame length too short: %u", m->m_pkthdr.len));
+
+	/*
+	 * In monitor mode, send everything directly to bpf.
+	 * XXX may want to include the CRC
+	 */
+	if (ic->ic_opmode == IEEE80211_M_MONITOR)
+		goto out;
 
 	wh = mtod(m, struct ieee80211_frame *);
 	if ((wh->i_fc[0] & IEEE80211_FC0_VERSION_MASK) !=
@@ -108,7 +117,16 @@ ieee80211_input(struct ifnet *ifp, struct mbuf *m, struct ieee80211_node *ni,
 	}
 
 	dir = wh->i_fc[1] & IEEE80211_FC1_DIR_MASK;
-
+	type = wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK;
+	/*
+	 * NB: We are not yet prepared to handle control frames,
+	 *     but permitting drivers to send them to us allows
+	 *     them to go through bpf tapping at the 802.11 layer.
+	 */
+	if (m->m_pkthdr.len < sizeof(struct ieee80211_frame)) {
+		/* XXX statistic */
+		goto out;		/* XXX */
+	}
 	if (ic->ic_state != IEEE80211_S_SCAN) {
 		switch (ic->ic_opmode) {
 		case IEEE80211_M_STA:
@@ -136,7 +154,6 @@ ieee80211_input(struct ifnet *ifp, struct mbuf *m, struct ieee80211_node *ni,
 			}
 			break;
 		case IEEE80211_M_MONITOR:
-			/* NB: this should collect everything */
 			goto out;
 		default:
 			/* XXX catch bad values */
@@ -156,7 +173,7 @@ ieee80211_input(struct ifnet *ifp, struct mbuf *m, struct ieee80211_node *ni,
 		ni->ni_inact = 0;
 	}
 
-	switch (wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) {
+	switch (type) {
 	case IEEE80211_FC0_TYPE_DATA:
 		switch (ic->ic_opmode) {
 		case IEEE80211_M_STA:
@@ -316,8 +333,9 @@ ieee80211_input(struct ifnet *ifp, struct mbuf *m, struct ieee80211_node *ni,
 		return;
 
 	case IEEE80211_FC0_TYPE_CTL:
+		goto out;
 	default:
-		IEEE80211_DPRINTF(("%s: bad type %x\n", __func__, wh->i_fc[0]));
+		IEEE80211_DPRINTF(("%s: bad type %x\n", __func__, type));
 		/* should not come here */
 		break;
 	}