diff options
Diffstat (limited to 'drivers/tty/n_gsm.c')
| -rw-r--r-- | drivers/tty/n_gsm.c | 59 |
1 files changed, 46 insertions, 13 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 04ef3ef0a422..5256087dd81b 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -184,6 +184,9 @@ struct gsm_mux { #define GSM_DATA 5 #define GSM_FCS 6 #define GSM_OVERRUN 7 +#define GSM_LEN0 8 +#define GSM_LEN1 9 +#define GSM_SSOF 10 unsigned int len; unsigned int address; unsigned int count; @@ -191,6 +194,7 @@ struct gsm_mux { int encoding; u8 control; u8 fcs; + u8 received_fcs; u8 *txframe; /* TX framing buffer */ /* Methods for the receiver side */ @@ -1623,7 +1627,6 @@ static void gsm_dlci_free(struct gsm_dlci *dlci) kfree(dlci); } - /* * LAPBish link layer logic */ @@ -1648,6 +1651,8 @@ static void gsm_queue(struct gsm_mux *gsm) if ((gsm->control & ~PF) == UI) gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf, gsm->len); + /* generate final CRC with received FCS */ + gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs); if (gsm->fcs != GOOD_FCS) { gsm->bad_fcs++; if (debug & 4) @@ -1746,6 +1751,8 @@ invalid: static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) { + unsigned int len; + switch (gsm->state) { case GSM_SEARCH: /* SOF marker */ if (c == GSM0_SOF) { @@ -1754,8 +1761,8 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) gsm->len = 0; gsm->fcs = INIT_FCS; } - break; /* Address EA */ - case GSM_ADDRESS: + break; + case GSM_ADDRESS: /* Address EA */ gsm->fcs = gsm_fcs_add(gsm->fcs, c); if (gsm_read_ea(&gsm->address, c)) gsm->state = GSM_CONTROL; @@ -1763,9 +1770,9 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) case GSM_CONTROL: /* Control Byte */ gsm->fcs = gsm_fcs_add(gsm->fcs, c); gsm->control = c; - gsm->state = GSM_LEN; + gsm->state = GSM_LEN0; break; - case GSM_LEN: /* Length EA */ + case GSM_LEN0: /* Length EA */ gsm->fcs = gsm_fcs_add(gsm->fcs, c); if (gsm_read_ea(&gsm->len, c)) { if (gsm->len > gsm->mru) { @@ -1774,8 +1781,28 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) break; } gsm->count = 0; - gsm->state = GSM_DATA; + if (!gsm->len) + gsm->state = GSM_FCS; + else + gsm->state = GSM_DATA; + break; } + gsm->state = GSM_LEN1; + break; + case GSM_LEN1: + gsm->fcs = gsm_fcs_add(gsm->fcs, c); + len = c; + gsm->len |= len << 7; + if (gsm->len > gsm->mru) { + gsm->bad_size++; + gsm->state = GSM_SEARCH; + break; + } + gsm->count = 0; + if (!gsm->len) + gsm->state = GSM_FCS; + else + gsm->state = GSM_DATA; break; case GSM_DATA: /* Data */ gsm->buf[gsm->count++] = c; @@ -1783,16 +1810,25 @@ static void gsm0_receive(struct gsm_mux *gsm, unsigned char c) gsm->state = GSM_FCS; break; case GSM_FCS: /* FCS follows the packet */ - gsm->fcs = c; + gsm->received_fcs = c; + if (c == GSM0_SOF) { + gsm->state = GSM_SEARCH; + break; + } gsm_queue(gsm); - /* And then back for the next frame */ - gsm->state = GSM_SEARCH; + gsm->state = GSM_SSOF; + break; + case GSM_SSOF: + if (c == GSM0_SOF) { + gsm->state = GSM_SEARCH; + break; + } break; } } /** - * gsm0_receive - perform processing for non-transparency + * gsm1_receive - perform processing for non-transparency * @gsm: gsm data for this ldisc instance * @c: character * @@ -2032,9 +2068,6 @@ struct gsm_mux *gsm_alloc_mux(void) } EXPORT_SYMBOL_GPL(gsm_alloc_mux); - - - /** * gsmld_output - write to link * @gsm: our mux |