isdn/gigaset: honor CAPI application's buffer size request

Fix the Gigaset CAPI driver to limit the length of a connection's
payload data receive buffers to the corresponding CAPI application's
data buffer size, as some real-life CAPI applications tend to be
rather unhappy if they receive bigger data blocks than requested.

Impact: bugfix
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 94 insertions, 112 deletions

diff --git a/drivers/isdn/gigaset/asyncdata.c b/drivers/isdn/gigaset/asyncdata.c
index c5016bd..c3b1dc3 100644
--- a/drivers/isdn/gigaset/asyncdata.c
+++ b/drivers/isdn/gigaset/asyncdata.c
@@ -126,26 +126,6 @@ static unsigned lock_loop(unsigned numbytes, struct inbuf_t *inbuf)
 	return numbytes;
 }
 
-/* set up next receive skb for data mode
- */
-static void new_rcv_skb(struct bc_state *bcs)
-{
-	struct cardstate *cs = bcs->cs;
-	unsigned short hw_hdr_len = cs->hw_hdr_len;
-
-	if (bcs->ignore) {
-		bcs->skb = NULL;
-		return;
-	}
-
-	bcs->skb = dev_alloc_skb(SBUFSIZE + hw_hdr_len);
-	if (bcs->skb == NULL) {
-		dev_warn(cs->dev, "could not allocate new skb\n");
-		return;
-	}
-	skb_reserve(bcs->skb, hw_hdr_len);
-}
-
 /* process a block of received bytes in HDLC data mode
  * (mstate != MS_LOCKED && !(inputstate & INS_command) && proto2 == L2_HDLC)
  * Collect HDLC frames, undoing byte stuffing and watching for DLE escapes.
@@ -159,8 +139,8 @@ static unsigned hdlc_loop(unsigned numbytes, struct inbuf_t *inbuf)
 	struct cardstate *cs = inbuf->cs;
 	struct bc_state *bcs = cs->bcs;
 	int inputstate = bcs->inputstate;
-	__u16 fcs = bcs->fcs;
-	struct sk_buff *skb = bcs->skb;
+	__u16 fcs = bcs->rx_fcs;
+	struct sk_buff *skb = bcs->rx_skb;
 	unsigned char *src = inbuf->data + inbuf->head;
 	unsigned procbytes = 0;
 	unsigned char c;
@@ -245,8 +225,7 @@ byte_stuff:
 
 				/* prepare reception of next frame */
 				inputstate &= ~INS_have_data;
-				new_rcv_skb(bcs);
-				skb = bcs->skb;
+				skb = gigaset_new_rx_skb(bcs);
 			} else {
 				/* empty frame (7E 7E) */
 #ifdef CONFIG_GIGASET_DEBUG
@@ -255,8 +234,7 @@ byte_stuff:
 				if (!skb) {
 					/* skipped (?) */
 					gigaset_isdn_rcv_err(bcs);
-					new_rcv_skb(bcs);
-					skb = bcs->skb;
+					skb = gigaset_new_rx_skb(bcs);
 				}
 			}
 
@@ -279,11 +257,11 @@ byte_stuff:
 #endif
 		inputstate |= INS_have_data;
 		if (skb) {
-			if (skb->len == SBUFSIZE) {
+			if (skb->len >= bcs->rx_bufsize) {
 				dev_warn(cs->dev, "received packet too long\n");
 				dev_kfree_skb_any(skb);
 				/* skip remainder of packet */
-				bcs->skb = skb = NULL;
+				bcs->rx_skb = skb = NULL;
 			} else {
 				*__skb_put(skb, 1) = c;
 				fcs = crc_ccitt_byte(fcs, c);
@@ -292,7 +270,7 @@ byte_stuff:
 	}
 
 	bcs->inputstate = inputstate;
-	bcs->fcs = fcs;
+	bcs->rx_fcs = fcs;
 	return procbytes;
 }
 
@@ -308,18 +286,18 @@ static unsigned iraw_loop(unsigned numbytes, struct inbuf_t *inbuf)
 	struct cardstate *cs = inbuf->cs;
 	struct bc_state *bcs = cs->bcs;
 	int inputstate = bcs->inputstate;
-	struct sk_buff *skb = bcs->skb;
+	struct sk_buff *skb = bcs->rx_skb;
 	unsigned char *src = inbuf->data + inbuf->head;
 	unsigned procbytes = 0;
 	unsigned char c;
 
 	if (!skb) {
 		/* skip this block */
-		new_rcv_skb(bcs);
+		gigaset_new_rx_skb(bcs);
 		return numbytes;
 	}
 
-	while (procbytes < numbytes && skb->len < SBUFSIZE) {
+	while (procbytes < numbytes && skb->len < bcs->rx_bufsize) {
 		c = *src++;
 		procbytes++;
 
@@ -343,7 +321,7 @@ static unsigned iraw_loop(unsigned numbytes, struct inbuf_t *inbuf)
 	if (inputstate & INS_have_data) {
 		gigaset_skb_rcvd(bcs, skb);
 		inputstate &= ~INS_have_data;
-		new_rcv_skb(bcs);
+		gigaset_new_rx_skb(bcs);
 	}
 
 	bcs->inputstate = inputstate;
diff --git a/drivers/isdn/gigaset/capi.c b/drivers/isdn/gigaset/capi.c
index 8f78f15..245a608 100644
--- a/drivers/isdn/gigaset/capi.c
+++ b/drivers/isdn/gigaset/capi.c
@@ -80,6 +80,7 @@ struct gigaset_capi_appl {
 	struct list_head ctrlist;
 	struct gigaset_capi_appl *bcnext;
 	u16 id;
+	struct capi_register_params rp;
 	u16 nextMessageNumber;
 	u32 listenInfoMask;
 	u32 listenCIPmask;
@@ -945,6 +946,7 @@ static void gigaset_register_appl(struct capi_ctr *ctr, u16 appl,
 		return;
 	}
 	ap->id = appl;
+	ap->rp = *rp;
 
 	list_add(&ap->ctrlist, &iif->appls);
 }
@@ -1166,6 +1168,9 @@ static void do_connect_req(struct gigaset_capi_ctr *iif,
 	}
 	ap->bcnext = NULL;
 	bcs->ap = ap;
+	bcs->rx_bufsize = ap->rp.datablklen;
+	dev_kfree_skb(bcs->rx_skb);
+	gigaset_new_rx_skb(bcs);
 	cmsg->adr.adrPLCI |= (bcs->channel + 1) << 8;
 
 	/* build command table */
@@ -1435,6 +1440,9 @@ static void do_connect_resp(struct gigaset_capi_ctr *iif,
 					CapiCallGivenToOtherApplication);
 		ap->bcnext = NULL;
 		bcs->ap = ap;
+		bcs->rx_bufsize = ap->rp.datablklen;
+		dev_kfree_skb(bcs->rx_skb);
+		gigaset_new_rx_skb(bcs);
 		bcs->chstate |= CHS_NOTIFY_LL;
 
 		/* check/encode B channel protocol */
diff --git a/drivers/isdn/gigaset/common.c b/drivers/isdn/gigaset/common.c
index f6f45f2..9778fab 100644
--- a/drivers/isdn/gigaset/common.c
+++ b/drivers/isdn/gigaset/common.c
@@ -399,8 +399,8 @@ static void gigaset_freebcs(struct bc_state *bcs)
 	gig_dbg(DEBUG_INIT, "clearing bcs[%d]->at_state", bcs->channel);
 	clear_at_state(&bcs->at_state);
 	gig_dbg(DEBUG_INIT, "freeing bcs[%d]->skb", bcs->channel);
-	dev_kfree_skb(bcs->skb);
-	bcs->skb = NULL;
+	dev_kfree_skb(bcs->rx_skb);
+	bcs->rx_skb = NULL;
 
 	for (i = 0; i < AT_NUM; ++i) {
 		kfree(bcs->commands[i]);
@@ -634,19 +634,10 @@ static struct bc_state *gigaset_initbcs(struct bc_state *bcs,
 	bcs->emptycount = 0;
 #endif
 
-	gig_dbg(DEBUG_INIT, "allocating bcs[%d]->skb", channel);
-	bcs->fcs = PPP_INITFCS;
+	bcs->rx_bufsize = 0;
+	bcs->rx_skb = NULL;
+	bcs->rx_fcs = PPP_INITFCS;
 	bcs->inputstate = 0;
-	if (cs->ignoreframes) {
-		bcs->skb = NULL;
-	} else {
-		bcs->skb = dev_alloc_skb(SBUFSIZE + cs->hw_hdr_len);
-		if (bcs->skb != NULL)
-			skb_reserve(bcs->skb, cs->hw_hdr_len);
-		else
-			pr_err("out of memory\n");
-	}
-
 	bcs->channel = channel;
 	bcs->cs = cs;
 
@@ -663,11 +654,6 @@ static struct bc_state *gigaset_initbcs(struct bc_state *bcs,
 		return bcs;
 
 	gig_dbg(DEBUG_INIT, "  failed");
-
-	gig_dbg(DEBUG_INIT, "  freeing bcs[%d]->skb", channel);
-	dev_kfree_skb(bcs->skb);
-	bcs->skb = NULL;
-
 	return NULL;
 }
 
@@ -839,14 +825,12 @@ void gigaset_bcs_reinit(struct bc_state *bcs)
 	bcs->emptycount = 0;
 #endif
 
-	bcs->fcs = PPP_INITFCS;
+	bcs->rx_fcs = PPP_INITFCS;
 	bcs->chstate = 0;
 
 	bcs->ignore = cs->ignoreframes;
-	if (bcs->ignore) {
-		dev_kfree_skb(bcs->skb);
-		bcs->skb = NULL;
-	}
+	dev_kfree_skb(bcs->rx_skb);
+	bcs->rx_skb = NULL;
 
 	cs->ops->reinitbcshw(bcs);
 }
diff --git a/drivers/isdn/gigaset/gigaset.h b/drivers/isdn/gigaset/gigaset.h
index 05947f9..f77ec54 100644
--- a/drivers/isdn/gigaset/gigaset.h
+++ b/drivers/isdn/gigaset/gigaset.h
@@ -45,10 +45,6 @@
 #define MAX_EVENTS 64		/* size of event queue */
 
 #define RBUFSIZE 8192
-#define SBUFSIZE 4096		/* sk_buff payload size */
-
-#define TRANSBUFSIZE 768	/* bytes per skb for transparent receive */
-#define MAX_BUF_SIZE (SBUFSIZE - 2)	/* Max. size of a data packet from LL */
 
 /* compile time options */
 #define GIG_MAJOR 0
@@ -380,8 +376,10 @@ struct bc_state {
 
 	struct at_state_t at_state;
 
-	__u16 fcs;
-	struct sk_buff *skb;
+	/* receive buffer */
+	unsigned rx_bufsize;		/* max size accepted by application */
+	struct sk_buff *rx_skb;
+	__u16 rx_fcs;
 	int inputstate;			/* see INS_XXXX */
 
 	int channel;
@@ -801,8 +799,23 @@ static inline void gigaset_bchannel_up(struct bc_state *bcs)
 	gigaset_schedule_event(bcs->cs);
 }
 
-/* handling routines for sk_buff */
-/* ============================= */
+/* set up next receive skb for data mode */
+static inline struct sk_buff *gigaset_new_rx_skb(struct bc_state *bcs)
+{
+	struct cardstate *cs = bcs->cs;
+	unsigned short hw_hdr_len = cs->hw_hdr_len;
+
+	if (bcs->ignore) {
+		bcs->rx_skb = NULL;
+	} else {
+		bcs->rx_skb = dev_alloc_skb(bcs->rx_bufsize + hw_hdr_len);
+		if (bcs->rx_skb == NULL)
+			dev_warn(cs->dev, "could not allocate skb\n");
+		else
+			skb_reserve(bcs->rx_skb, hw_hdr_len);
+	}
+	return bcs->rx_skb;
+}
 
 /* append received bytes to inbuf */
 int gigaset_fill_inbuf(struct inbuf_t *inbuf, const unsigned char *src,
diff --git a/drivers/isdn/gigaset/i4l.c b/drivers/isdn/gigaset/i4l.c
index c22e5ac..f01c3c2 100644
--- a/drivers/isdn/gigaset/i4l.c
+++ b/drivers/isdn/gigaset/i4l.c
@@ -16,7 +16,10 @@
 #include "gigaset.h"
 #include <linux/isdnif.h>
 
+#define SBUFSIZE	4096	/* sk_buff payload size */
+#define TRANSBUFSIZE	768	/* bytes per skb for transparent receive */
 #define HW_HDR_LEN	2	/* Header size used to store ack info */
+#define MAX_BUF_SIZE	(SBUFSIZE - HW_HDR_LEN)	/* max data packet from LL */
 
 /* == Handling of I4L IO =====================================================*/
 
@@ -231,6 +234,15 @@ static int command_from_LL(isdn_ctrl *cntrl)
 			dev_err(cs->dev, "ISDN_CMD_DIAL: channel not free\n");
 			return -EBUSY;
 		}
+		switch (bcs->proto2) {
+		case L2_HDLC:
+			bcs->rx_bufsize = SBUFSIZE;
+			break;
+		default:			/* assume transparent */
+			bcs->rx_bufsize = TRANSBUFSIZE;
+		}
+		dev_kfree_skb(bcs->rx_skb);
+		gigaset_new_rx_skb(bcs);
 
 		commands = kzalloc(AT_NUM*(sizeof *commands), GFP_ATOMIC);
 		if (!commands) {
@@ -314,6 +326,15 @@ static int command_from_LL(isdn_ctrl *cntrl)
 			return -EINVAL;
 		}
 		bcs = cs->bcs + ch;
+		switch (bcs->proto2) {
+		case L2_HDLC:
+			bcs->rx_bufsize = SBUFSIZE;
+			break;
+		default:			/* assume transparent */
+			bcs->rx_bufsize = TRANSBUFSIZE;
+		}
+		dev_kfree_skb(bcs->rx_skb);
+		gigaset_new_rx_skb(bcs);
 		if (!gigaset_add_event(cs, &bcs->at_state,
 				       EV_ACCEPT, NULL, 0, NULL))
 			return -ENOMEM;
diff --git a/drivers/isdn/gigaset/isocdata.c b/drivers/isdn/gigaset/isocdata.c
index 16fd3bd..2dfd346 100644
--- a/drivers/isdn/gigaset/isocdata.c
+++ b/drivers/isdn/gigaset/isocdata.c
@@ -500,19 +500,18 @@ int gigaset_isoc_buildframe(struct bc_state *bcs, unsigned char *in, int len)
  */
 static inline void hdlc_putbyte(unsigned char c, struct bc_state *bcs)
 {
-	bcs->fcs = crc_ccitt_byte(bcs->fcs, c);
-	if (unlikely(bcs->skb == NULL)) {
+	bcs->rx_fcs = crc_ccitt_byte(bcs->rx_fcs, c);
+	if (bcs->rx_skb == NULL)
 		/* skipping */
 		return;
-	}
-	if (unlikely(bcs->skb->len == SBUFSIZE)) {
+	if (bcs->rx_skb->len >= bcs->rx_bufsize) {
 		dev_warn(bcs->cs->dev, "received oversized packet discarded\n");
 		bcs->hw.bas->giants++;
-		dev_kfree_skb_any(bcs->skb);
-		bcs->skb = NULL;
+		dev_kfree_skb_any(bcs->rx_skb);
+		bcs->rx_skb = NULL;
 		return;
 	}
-	*__skb_put(bcs->skb, 1) = c;
+	*__skb_put(bcs->rx_skb, 1) = c;
 }
 
 /* hdlc_flush
@@ -521,18 +520,13 @@ static inline void hdlc_putbyte(unsigned char c, struct bc_state *bcs)
 static inline void hdlc_flush(struct bc_state *bcs)
 {
 	/* clear skb or allocate new if not skipping */
-	if (likely(bcs->skb != NULL))
-		skb_trim(bcs->skb, 0);
-	else if (!bcs->ignore) {
-		bcs->skb = dev_alloc_skb(SBUFSIZE + bcs->cs->hw_hdr_len);
-		if (bcs->skb)
-			skb_reserve(bcs->skb, bcs->cs->hw_hdr_len);
-		else
-			dev_err(bcs->cs->dev, "could not allocate skb\n");
-	}
+	if (bcs->rx_skb != NULL)
+		skb_trim(bcs->rx_skb, 0);
+	else
+		gigaset_new_rx_skb(bcs);
 
 	/* reset packet state */
-	bcs->fcs = PPP_INITFCS;
+	bcs->rx_fcs = PPP_INITFCS;
 }
 
 /* hdlc_done
@@ -549,7 +543,7 @@ static inline void hdlc_done(struct bc_state *bcs)
 		hdlc_flush(bcs);
 		return;
 	}
-	procskb = bcs->skb;
+	procskb = bcs->rx_skb;
 	if (procskb == NULL) {
 		/* previous error */
 		gig_dbg(DEBUG_ISO, "%s: skb=NULL", __func__);
@@ -560,8 +554,8 @@ static inline void hdlc_done(struct bc_state *bcs)
 		bcs->hw.bas->runts++;
 		dev_kfree_skb_any(procskb);
 		gigaset_isdn_rcv_err(bcs);
-	} else if (bcs->fcs != PPP_GOODFCS) {
-		dev_notice(cs->dev, "frame check error (0x%04x)\n", bcs->fcs);
+	} else if (bcs->rx_fcs != PPP_GOODFCS) {
+		dev_notice(cs->dev, "frame check error\n");
 		bcs->hw.bas->fcserrs++;
 		dev_kfree_skb_any(procskb);
 		gigaset_isdn_rcv_err(bcs);
@@ -574,13 +568,8 @@ static inline void hdlc_done(struct bc_state *bcs)
 		bcs->hw.bas->goodbytes += len;
 		gigaset_skb_rcvd(bcs, procskb);
 	}
-
-	bcs->skb = dev_alloc_skb(SBUFSIZE + cs->hw_hdr_len);
-	if (bcs->skb)
-		skb_reserve(bcs->skb, cs->hw_hdr_len);
-	else
-		dev_err(cs->dev, "could not allocate skb\n");
-	bcs->fcs = PPP_INITFCS;
+	gigaset_new_rx_skb(bcs);
+	bcs->rx_fcs = PPP_INITFCS;
 }
 
 /* hdlc_frag
@@ -597,8 +586,8 @@ static inline void hdlc_frag(struct bc_state *bcs, unsigned inbits)
 	dev_notice(bcs->cs->dev, "received partial byte (%d bits)\n", inbits);
 	bcs->hw.bas->alignerrs++;
 	gigaset_isdn_rcv_err(bcs);
-	__skb_trim(bcs->skb, 0);
-	bcs->fcs = PPP_INITFCS;
+	__skb_trim(bcs->rx_skb, 0);
+	bcs->rx_fcs = PPP_INITFCS;
 }
 
 /* bit counts lookup table for HDLC bit unstuffing
@@ -847,7 +836,6 @@ static inline void hdlc_unpack(unsigned char *src, unsigned count,
 static inline void trans_receive(unsigned char *src, unsigned count,
 				 struct bc_state *bcs)
 {
-	struct cardstate *cs = bcs->cs;
 	struct sk_buff *skb;
 	int dobytes;
 	unsigned char *dst;
@@ -857,17 +845,11 @@ static inline void trans_receive(unsigned char *src, unsigned count,
 		hdlc_flush(bcs);
 		return;
 	}
-	skb = bcs->skb;
-	if (unlikely(skb == NULL)) {
-		bcs->skb = skb = dev_alloc_skb(SBUFSIZE + cs->hw_hdr_len);
-		if (!skb) {
-			dev_err(cs->dev, "could not allocate skb\n");
-			return;
-		}
-		skb_reserve(skb, cs->hw_hdr_len);
-	}
+	skb = bcs->rx_skb;
+	if (skb == NULL)
+		skb = gigaset_new_rx_skb(bcs);
 	bcs->hw.bas->goodbytes += skb->len;
-	dobytes = TRANSBUFSIZE - skb->len;
+	dobytes = bcs->rx_bufsize - skb->len;
 	while (count > 0) {
 		dst = skb_put(skb, count < dobytes ? count : dobytes);
 		while (count > 0 && dobytes > 0) {
@@ -879,14 +861,10 @@ static inline void trans_receive(unsigned char *src, unsigned count,
 			dump_bytes(DEBUG_STREAM_DUMP,
 				   "rcv data", skb->data, skb->len);
 			gigaset_skb_rcvd(bcs, skb);
-			bcs->skb = skb =
-				dev_alloc_skb(SBUFSIZE + cs->hw_hdr_len);
-			if (!skb) {
-				dev_err(cs->dev, "could not allocate skb\n");
+			skb = gigaset_new_rx_skb(bcs);
+			if (skb == NULL)
 				return;
-			}
-			skb_reserve(skb, cs->hw_hdr_len);
-			dobytes = TRANSBUFSIZE;
+			dobytes = bcs->rx_bufsize;
 		}
 	}
 }