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 c5016bd2d94..c3b1dc3a13a 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 8f78f15c8ef..245a6083f79 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 f6f45f22192..9778fabbc48 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 05947f9c184..f77ec54eb07 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 c22e5ace827..f01c3c2e2e4 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 16fd3bd4888..2dfd346fc88 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;
                 }
         }
 }