ISDN: Fix isdnhdlc for one byte hdlc packets

Normally HDLC packets contain more as one byte (e.g a X25/X75 header).
But if you use plain HDLC framing, the current code do not encode
1 byte payloads, this patch fix that.

Signed-off-by: Karsten Keil <keil@b1-systems.de>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/isdn/i4l/isdnhdlc.c b/drivers/isdn/i4l/isdnhdlc.c
index df345ce73f4..c989aa35dc2 100644
--- a/drivers/isdn/i4l/isdnhdlc.c
+++ b/drivers/isdn/i4l/isdnhdlc.c
@@ -47,7 +47,7 @@ enum {
         HDLC_SEND_DATA, HDLC_SEND_CRC1, HDLC_SEND_FAST_FLAG,
         HDLC_SEND_FIRST_FLAG, HDLC_SEND_CRC2, HDLC_SEND_CLOSING_FLAG,
         HDLC_SEND_IDLE1, HDLC_SEND_FAST_IDLE, HDLC_SENDFLAG_B0,
-        HDLC_SENDFLAG_B1A6, HDLC_SENDFLAG_B7, STOPPED
+        HDLC_SENDFLAG_B1A6, HDLC_SENDFLAG_B7, STOPPED, HDLC_SENDFLAG_ONE
 };
 
 void isdnhdlc_rcv_init(struct isdnhdlc_vars *hdlc, u32 features)
@@ -362,6 +362,9 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src, u16 slen,
 
         *count = slen;
 
+        /* special handling for one byte frames */
+        if ((slen == 1) && (hdlc->state == HDLC_SEND_FAST_FLAG))
+                hdlc->state = HDLC_SENDFLAG_ONE;
         while (dsize > 0) {
                 if (hdlc->bit_shift == 0) {
                         if (slen && !hdlc->do_closing) {
@@ -407,6 +410,8 @@ int isdnhdlc_encode(struct isdnhdlc_vars *hdlc, const u8 *src, u16 slen,
                                 dsize--;
                                 break;
                         }
+                        /* fall through */
+                case HDLC_SENDFLAG_ONE:
                         if (hdlc->bit_shift == 8) {
                                 hdlc->cbin = hdlc->ffvalue >>
                                         (8 - hdlc->data_bits);