move ieee80211_compute_duration() and ieee80211_compute_duration1()

functions into the two drivers that use them (atw and rtw.)
this code is not generic enough to be used by other drivers and
there is no chance that it will ever be used in newer driver since
it supports 802.11b only.
plus, it hurts my eyes each time i look into ieee80211_output.c.

"fine with me as long as the logic doesn't change in the functions" jsg@

4 files changed, 363 insertions, 11 deletions

diff --git a/sys/dev/ic/atw.c b/sys/dev/ic/atw.c
index 02bdc497f9e..a6a42f15b75 100644
--- a/sys/dev/ic/atw.c
+++ b/sys/dev/ic/atw.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: atw.c,v 1.52 2007/02/14 04:49:43 jsg Exp $	*/
+/*	$OpenBSD: atw.c,v 1.53 2007/06/07 20:20:15 damien Exp $	*/
 /*	$NetBSD: atw.c,v 1.69 2004/07/23 07:07:55 dyoung Exp $	*/
 
 /*-
@@ -255,6 +255,9 @@ void	atw_node_free(struct ieee80211com *, struct ieee80211_node *);
 static	__inline uint32_t atw_last_even_tsft(uint32_t, uint32_t, uint32_t);
 uint64_t atw_get_tsft(struct atw_softc *sc);
 void	atw_change_ibss(struct atw_softc *);
+int	atw_compute_duration1(int, int, uint32_t, int, struct atw_duration *);
+int	atw_compute_duration(struct ieee80211_frame *, int, uint32_t, int,
+	    int, struct atw_duration *, struct atw_duration *, int *, int);
 
 /*
  * Tuner/transceiver/modem
@@ -3410,6 +3413,171 @@ atw_watchdog(struct ifnet *ifp)
 	ieee80211_watchdog(ifp);
 }
 
+/*
+ * Arguments in:
+ *
+ * paylen:  payload length (no FCS, no WEP header)
+ *
+ * hdrlen:  header length
+ *
+ * rate:    MSDU speed, units 500kb/s
+ *
+ * flags:   IEEE80211_F_SHPREAMBLE (use short preamble),
+ *          IEEE80211_F_SHSLOT (use short slot length)
+ *
+ * Arguments out:
+ *
+ * d:       802.11 Duration field for RTS,
+ *          802.11 Duration field for data frame,
+ *          PLCP Length for data frame,
+ *          residual octets at end of data slot
+ */
+int
+atw_compute_duration1(int len, int use_ack, uint32_t flags, int rate,
+    struct atw_duration *d)
+{
+	int pre, ctsrate;
+	int ack, bitlen, data_dur, remainder;
+
+	/* RTS reserves medium for SIFS | CTS | SIFS | (DATA) | SIFS | ACK
+	 * DATA reserves medium for SIFS | ACK
+	 *
+	 * XXXMYC: no ACK on multicast/broadcast or control packets
+	 */
+
+	bitlen = len * 8;
+
+	pre = IEEE80211_DUR_DS_SIFS;
+	if ((flags & IEEE80211_F_SHPREAMBLE) != 0)
+		pre += IEEE80211_DUR_DS_SHORT_PREAMBLE +
+		    IEEE80211_DUR_DS_FAST_PLCPHDR;
+	else
+		pre += IEEE80211_DUR_DS_LONG_PREAMBLE +
+		    IEEE80211_DUR_DS_SLOW_PLCPHDR;
+
+	d->d_residue = 0;
+	data_dur = (bitlen * 2) / rate;
+	remainder = (bitlen * 2) % rate;
+	if (remainder != 0) {
+		d->d_residue = (rate - remainder) / 16;
+		data_dur++;
+	}
+
+	switch (rate) {
+	case 2:		/* 1 Mb/s */
+	case 4:		/* 2 Mb/s */
+		/* 1 - 2 Mb/s WLAN: send ACK/CTS at 1 Mb/s */
+		ctsrate = 2;
+		break;
+	case 11:	/* 5.5 Mb/s */
+	case 22:	/* 11  Mb/s */
+	case 44:	/* 22  Mb/s */
+		/* 5.5 - 11 Mb/s WLAN: send ACK/CTS at 2 Mb/s */
+		ctsrate = 4;
+		break;
+	default:
+		/* TBD */
+		return -1;
+	}
+
+	d->d_plcp_len = data_dur;
+
+	ack = (use_ack) ? pre + (IEEE80211_DUR_DS_SLOW_ACK * 2) / ctsrate : 0;
+
+	d->d_rts_dur =
+	    pre + (IEEE80211_DUR_DS_SLOW_CTS * 2) / ctsrate +
+	    pre + data_dur +
+	    ack;
+
+	d->d_data_dur = ack;
+
+	return 0;
+}
+
+/*
+ * Arguments in:
+ *
+ * wh:      802.11 header
+ *
+ * len: packet length 
+ *
+ * rate:    MSDU speed, units 500kb/s
+ *
+ * fraglen: fragment length, set to maximum (or higher) for no
+ *          fragmentation
+ *
+ * flags:   IEEE80211_F_WEPON (hardware adds WEP),
+ *          IEEE80211_F_SHPREAMBLE (use short preamble),
+ *          IEEE80211_F_SHSLOT (use short slot length)
+ *
+ * Arguments out:
+ *
+ * d0: 802.11 Duration fields (RTS/Data), PLCP Length, Service fields
+ *     of first/only fragment
+ *
+ * dn: 802.11 Duration fields (RTS/Data), PLCP Length, Service fields
+ *     of first/only fragment
+ */
+int
+atw_compute_duration(struct ieee80211_frame *wh, int len, uint32_t flags,
+    int fraglen, int rate, struct atw_duration *d0, struct atw_duration *dn,
+    int *npktp, int debug)
+{
+	int ack, rc;
+	int firstlen, hdrlen, lastlen, lastlen0, npkt, overlen, paylen;
+
+	if ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS)
+		hdrlen = sizeof(struct ieee80211_frame_addr4);
+	else
+		hdrlen = sizeof(struct ieee80211_frame);
+
+	paylen = len - hdrlen;
+
+	if ((flags & IEEE80211_F_WEPON) != 0)
+		overlen = IEEE80211_WEP_TOTLEN + IEEE80211_CRC_LEN;
+	else
+		overlen = IEEE80211_CRC_LEN;
+
+	npkt = paylen / fraglen;
+	lastlen0 = paylen % fraglen;
+
+	if (npkt == 0)			/* no fragments */
+		lastlen = paylen + overlen;
+	else if (lastlen0 != 0) {	/* a short "tail" fragment */
+		lastlen = lastlen0 + overlen;
+		npkt++;
+	} else				/* full-length "tail" fragment */
+		lastlen = fraglen + overlen;
+
+	if (npktp != NULL)
+		*npktp = npkt;
+
+	if (npkt > 1)
+		firstlen = fraglen + overlen;
+	else
+		firstlen = paylen + overlen;
+
+	if (debug) {
+		printf("%s: npkt %d firstlen %d lastlen0 %d lastlen %d "
+		    "fraglen %d overlen %d len %d rate %d flags %08x\n",
+		    __func__, npkt, firstlen, lastlen0, lastlen, fraglen,
+		    overlen, len, rate, flags);
+	}
+
+	ack = !IEEE80211_IS_MULTICAST(wh->i_addr1) &&
+	    (wh->i_fc[1] & IEEE80211_FC0_TYPE_MASK) != IEEE80211_FC0_TYPE_CTL;
+
+	rc = atw_compute_duration1(firstlen + hdrlen, ack, flags, rate, d0);
+	if (rc == -1)
+		return rc;
+
+	if (npkt <= 1) {
+		*dn = *d0;
+		return 0;
+	}
+	return atw_compute_duration1(lastlen + hdrlen, ack, flags, rate, dn);
+}
+
 #ifdef ATW_DEBUG
 void
 atw_dump_pkt(struct ifnet *ifp, struct mbuf *m0)
@@ -3520,7 +3688,7 @@ atw_start(struct ifnet *ifp)
 		else
 			rate = MAX(2, ieee80211_get_rate(ic));
 
-		if (ieee80211_compute_duration(wh, m0->m_pkthdr.len,
+		if (atw_compute_duration(wh, m0->m_pkthdr.len,
 		    ic->ic_flags & ~IEEE80211_F_WEPON, ic->ic_fragthreshold,
 		    rate, &txs->txs_d0, &txs->txs_dn, &npkt,
 		    (sc->sc_if.if_flags & (IFF_DEBUG|IFF_LINK2)) ==
diff --git a/sys/dev/ic/atwvar.h b/sys/dev/ic/atwvar.h
index e1e23c11116..0bb116e1a1f 100644
--- a/sys/dev/ic/atwvar.h
+++ b/sys/dev/ic/atwvar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: atwvar.h,v 1.12 2006/06/27 04:25:12 jsg Exp $	*/
+/*	$OpenBSD: atwvar.h,v 1.13 2007/06/07 20:20:15 damien Exp $	*/
 /*	$NetBSD: atwvar.h,v 1.13 2004/07/23 07:07:55 dyoung Exp $	*/
 
 /*
@@ -95,6 +95,14 @@ struct atw_control_data {
 #define	ATW_CDOFF(x)		offsetof(struct atw_control_data, x)
 #define	ATW_CDTXOFF(x)	ATW_CDOFF(acd_txdescs[(x)])
 #define	ATW_CDRXOFF(x)	ATW_CDOFF(acd_rxdescs[(x)])
+
+struct atw_duration {
+	uint16_t	d_rts_dur;
+	uint16_t	d_data_dur;
+	uint16_t	d_plcp_len;
+	uint8_t		d_residue;	/* unused octets in time slot */
+};
+
 /*
  * Software state for transmit jobs.
  */
@@ -104,8 +112,8 @@ struct atw_txsoft {
 	int txs_firstdesc;		/* first descriptor in packet */
 	int txs_lastdesc;		/* last descriptor in packet */
 	int txs_ndescs;			/* number of descriptors */
-	struct ieee80211_duration txs_d0;
-	struct ieee80211_duration txs_dn;
+	struct atw_duration txs_d0;
+	struct atw_duration txs_dn;
 	SIMPLEQ_ENTRY(atw_txsoft) txs_q;
 };
 
diff --git a/sys/dev/ic/rtw.c b/sys/dev/ic/rtw.c
index 036da8950e9..50dafe4da42 100644
--- a/sys/dev/ic/rtw.c
+++ b/sys/dev/ic/rtw.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtw.c,v 1.60 2007/04/06 12:20:59 jsg Exp $	*/
+/*	$OpenBSD: rtw.c,v 1.61 2007/06/07 20:20:15 damien Exp $	*/
 /*	$NetBSD: rtw.c,v 1.29 2004/12/27 19:49:16 dyoung Exp $ */
 
 /*-
@@ -145,6 +145,9 @@ void	 rtw_rfmd_pwrstate(struct rtw_regs *, enum rtw_pwrstate, int, int);
 int	 rtw_pwrstate(struct rtw_softc *, enum rtw_pwrstate);
 int	 rtw_tune(struct rtw_softc *);
 void	 rtw_set_nettype(struct rtw_softc *, enum ieee80211_opmode);
+int	 rtw_compute_duration1(int, int, uint32_t, int, struct rtw_duration *);
+int	 rtw_compute_duration(struct ieee80211_frame *, int, uint32_t, int,
+	    int, struct rtw_duration *, struct rtw_duration *, int *, int);
 int	 rtw_init(struct ifnet *);
 int	 rtw_ioctl(struct ifnet *, u_long, caddr_t);
 int	 rtw_seg_too_short(bus_dmamap_t);
@@ -2926,6 +2929,172 @@ rtw_dmamap_load_txbuf(bus_dma_tag_t dmat, bus_dmamap_t dmam, struct mbuf *chain,
 	return m0;
 }
 
+
+/*
+ * Arguments in:
+ *
+ * paylen:  payload length (no FCS, no WEP header)
+ *
+ * hdrlen:  header length
+ *
+ * rate:    MSDU speed, units 500kb/s
+ *
+ * flags:   IEEE80211_F_SHPREAMBLE (use short preamble),
+ *          IEEE80211_F_SHSLOT (use short slot length)
+ *
+ * Arguments out:
+ *
+ * d:       802.11 Duration field for RTS,
+ *          802.11 Duration field for data frame,
+ *          PLCP Length for data frame,
+ *          residual octets at end of data slot
+ */
+int
+rtw_compute_duration1(int len, int use_ack, uint32_t flags, int rate,
+    struct rtw_duration *d)
+{
+	int pre, ctsrate;
+	int ack, bitlen, data_dur, remainder;
+
+	/* RTS reserves medium for SIFS | CTS | SIFS | (DATA) | SIFS | ACK
+	 * DATA reserves medium for SIFS | ACK
+	 *
+	 * XXXMYC: no ACK on multicast/broadcast or control packets
+	 */
+
+	bitlen = len * 8;
+
+	pre = IEEE80211_DUR_DS_SIFS;
+	if ((flags & IEEE80211_F_SHPREAMBLE) != 0)
+		pre += IEEE80211_DUR_DS_SHORT_PREAMBLE +
+		    IEEE80211_DUR_DS_FAST_PLCPHDR;
+	else
+		pre += IEEE80211_DUR_DS_LONG_PREAMBLE +
+		    IEEE80211_DUR_DS_SLOW_PLCPHDR;
+
+	d->d_residue = 0;
+	data_dur = (bitlen * 2) / rate;
+	remainder = (bitlen * 2) % rate;
+	if (remainder != 0) {
+		d->d_residue = (rate - remainder) / 16;
+		data_dur++;
+	}
+
+	switch (rate) {
+	case 2:		/* 1 Mb/s */
+	case 4:		/* 2 Mb/s */
+		/* 1 - 2 Mb/s WLAN: send ACK/CTS at 1 Mb/s */
+		ctsrate = 2;
+		break;
+	case 11:	/* 5.5 Mb/s */
+	case 22:	/* 11  Mb/s */
+	case 44:	/* 22  Mb/s */
+		/* 5.5 - 11 Mb/s WLAN: send ACK/CTS at 2 Mb/s */
+		ctsrate = 4;
+		break;
+	default:
+		/* TBD */
+		return -1;
+	}
+
+	d->d_plcp_len = data_dur;
+
+	ack = (use_ack) ? pre + (IEEE80211_DUR_DS_SLOW_ACK * 2) / ctsrate : 0;
+
+	d->d_rts_dur =
+	    pre + (IEEE80211_DUR_DS_SLOW_CTS * 2) / ctsrate +
+	    pre + data_dur +
+	    ack;
+
+	d->d_data_dur = ack;
+
+	return 0;
+}
+
+/*
+ * Arguments in:
+ *
+ * wh:      802.11 header
+ *
+ * len: packet length 
+ *
+ * rate:    MSDU speed, units 500kb/s
+ *
+ * fraglen: fragment length, set to maximum (or higher) for no
+ *          fragmentation
+ *
+ * flags:   IEEE80211_F_WEPON (hardware adds WEP),
+ *          IEEE80211_F_SHPREAMBLE (use short preamble),
+ *          IEEE80211_F_SHSLOT (use short slot length)
+ *
+ * Arguments out:
+ *
+ * d0: 802.11 Duration fields (RTS/Data), PLCP Length, Service fields
+ *     of first/only fragment
+ *
+ * dn: 802.11 Duration fields (RTS/Data), PLCP Length, Service fields
+ *     of first/only fragment
+ */
+int
+rtw_compute_duration(struct ieee80211_frame *wh, int len, uint32_t flags,
+    int fraglen, int rate, struct rtw_duration *d0, struct rtw_duration *dn,
+    int *npktp, int debug)
+{
+	int ack, rc;
+	int firstlen, hdrlen, lastlen, lastlen0, npkt, overlen, paylen;
+
+	if ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS)
+		hdrlen = sizeof(struct ieee80211_frame_addr4);
+	else
+		hdrlen = sizeof(struct ieee80211_frame);
+
+	paylen = len - hdrlen;
+
+	if ((flags & IEEE80211_F_WEPON) != 0)
+		overlen = IEEE80211_WEP_TOTLEN + IEEE80211_CRC_LEN;
+	else
+		overlen = IEEE80211_CRC_LEN;
+
+	npkt = paylen / fraglen;
+	lastlen0 = paylen % fraglen;
+
+	if (npkt == 0)			/* no fragments */
+		lastlen = paylen + overlen;
+	else if (lastlen0 != 0) {	/* a short "tail" fragment */
+		lastlen = lastlen0 + overlen;
+		npkt++;
+	} else				/* full-length "tail" fragment */
+		lastlen = fraglen + overlen;
+
+	if (npktp != NULL)
+		*npktp = npkt;
+
+	if (npkt > 1)
+		firstlen = fraglen + overlen;
+	else
+		firstlen = paylen + overlen;
+
+	if (debug) {
+		printf("%s: npkt %d firstlen %d lastlen0 %d lastlen %d "
+		    "fraglen %d overlen %d len %d rate %d flags %08x\n",
+		    __func__, npkt, firstlen, lastlen0, lastlen, fraglen,
+		    overlen, len, rate, flags);
+	}
+
+	ack = !IEEE80211_IS_MULTICAST(wh->i_addr1) &&
+	    (wh->i_fc[1] & IEEE80211_FC0_TYPE_MASK) != IEEE80211_FC0_TYPE_CTL;
+
+	rc = rtw_compute_duration1(firstlen + hdrlen, ack, flags, rate, d0);
+	if (rc == -1)
+		return rc;
+
+	if (npkt <= 1) {
+		*dn = *d0;
+		return 0;
+	}
+	return rtw_compute_duration1(lastlen + hdrlen, ack, flags, rate, dn);
+}
+
 #ifdef RTW_DEBUG
 void
 rtw_print_txdesc(struct rtw_softc *sc, const char *action,
@@ -2949,11 +3118,11 @@ rtw_start(struct ifnet *ifp)
 	uint32_t proto_ctl0, ctl0, ctl1;
 	bus_dmamap_t		dmamap;
 	struct ieee80211com	*ic;
-	struct ieee80211_duration *d0;
 	struct ieee80211_frame	*wh;
 	struct ieee80211_node	*ni;
 	struct mbuf		*m0;
 	struct rtw_softc	*sc;
+	struct rtw_duration	*d0;
 	struct rtw_txsoft_blk	*tsb;
 	struct rtw_txdesc_blk	*tdb;
 	struct rtw_txsoft	*ts;
@@ -3040,7 +3209,7 @@ rtw_start(struct ifnet *ifp)
 				ctl0 |= RTW_TXCTL0_BEACON;
 		}
 
-		if (ieee80211_compute_duration(wh, m0->m_pkthdr.len,
+		if (rtw_compute_duration(wh, m0->m_pkthdr.len,
 		    ic->ic_flags & ~IEEE80211_F_WEPON, ic->ic_fragthreshold,
 		    rate, &ts->ts_d0, &ts->ts_dn, &npkt,
 		    (sc->sc_if.if_flags & (IFF_DEBUG|IFF_LINK2)) ==
diff --git a/sys/dev/ic/rtwvar.h b/sys/dev/ic/rtwvar.h
index e5936aaeabe..fbadf60822f 100644
--- a/sys/dev/ic/rtwvar.h
+++ b/sys/dev/ic/rtwvar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtwvar.h,v 1.22 2006/06/27 04:25:12 jsg Exp $	*/
+/*	$OpenBSD: rtwvar.h,v 1.23 2007/06/07 20:20:15 damien Exp $	*/
 /*	$NetBSD: rtwvar.h,v 1.10 2004/12/26 22:37:57 mycroft Exp $	*/
 
 /*-
@@ -154,6 +154,13 @@ struct rtw_rxsoft {
 	bus_dmamap_t			rs_dmamap;
 };
 
+struct rtw_duration {
+	uint16_t	d_rts_dur;
+	uint16_t	d_data_dur;
+	uint16_t	d_plcp_len;
+	uint8_t		d_residue;	/* unused octets in time slot */
+};
+
 struct rtw_txsoft {
 	SIMPLEQ_ENTRY(rtw_txsoft)	ts_q;
 	struct mbuf			*ts_mbuf;
@@ -161,8 +168,8 @@ struct rtw_txsoft {
 	struct ieee80211_node		*ts_ni;	/* destination node */
 	u_int				ts_first;	/* 1st hw descriptor */
 	u_int				ts_last;	/* last hw descriptor */
-	struct ieee80211_duration	ts_d0;
-	struct ieee80211_duration	ts_dn;
+	struct rtw_duration		ts_d0;
+	struct rtw_duration		ts_dn;
 };
 
 #define RTW_NTXPRI	4	/* number of Tx priorities */