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path: root/drivers/tty/n_gsm.c
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Diffstat (limited to 'drivers/tty/n_gsm.c')
-rw-r--r--drivers/tty/n_gsm.c140
1 files changed, 97 insertions, 43 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 4036566fe..afbf7837b 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -245,16 +245,18 @@ enum gsm_encoding {
enum gsm_mux_state {
GSM_SEARCH,
- GSM_START,
- GSM_ADDRESS,
- GSM_CONTROL,
- GSM_LEN,
- GSM_DATA,
- GSM_FCS,
- GSM_OVERRUN,
- GSM_LEN0,
- GSM_LEN1,
- GSM_SSOF,
+ GSM0_ADDRESS,
+ GSM0_CONTROL,
+ GSM0_LEN0,
+ GSM0_LEN1,
+ GSM0_DATA,
+ GSM0_FCS,
+ GSM0_SSOF,
+ GSM1_START,
+ GSM1_ADDRESS,
+ GSM1_CONTROL,
+ GSM1_DATA,
+ GSM1_OVERRUN,
};
/*
@@ -2847,6 +2849,30 @@ invalid:
return;
}
+/**
+ * gsm0_receive_state_check_and_fix - check and correct receive state
+ * @gsm: gsm data for this ldisc instance
+ *
+ * Ensures that the current receive state is valid for basic option mode.
+ */
+
+static void gsm0_receive_state_check_and_fix(struct gsm_mux *gsm)
+{
+ switch (gsm->state) {
+ case GSM_SEARCH:
+ case GSM0_ADDRESS:
+ case GSM0_CONTROL:
+ case GSM0_LEN0:
+ case GSM0_LEN1:
+ case GSM0_DATA:
+ case GSM0_FCS:
+ case GSM0_SSOF:
+ break;
+ default:
+ gsm->state = GSM_SEARCH;
+ break;
+ }
+}
/**
* gsm0_receive - perform processing for non-transparency
@@ -2860,26 +2886,27 @@ static void gsm0_receive(struct gsm_mux *gsm, u8 c)
{
unsigned int len;
+ gsm0_receive_state_check_and_fix(gsm);
switch (gsm->state) {
case GSM_SEARCH: /* SOF marker */
if (c == GSM0_SOF) {
- gsm->state = GSM_ADDRESS;
+ gsm->state = GSM0_ADDRESS;
gsm->address = 0;
gsm->len = 0;
gsm->fcs = INIT_FCS;
}
break;
- case GSM_ADDRESS: /* Address EA */
+ case GSM0_ADDRESS: /* Address EA */
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
if (gsm_read_ea(&gsm->address, c))
- gsm->state = GSM_CONTROL;
+ gsm->state = GSM0_CONTROL;
break;
- case GSM_CONTROL: /* Control Byte */
+ case GSM0_CONTROL: /* Control Byte */
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
gsm->control = c;
- gsm->state = GSM_LEN0;
+ gsm->state = GSM0_LEN0;
break;
- case GSM_LEN0: /* Length EA */
+ case GSM0_LEN0: /* Length EA */
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
if (gsm_read_ea(&gsm->len, c)) {
if (gsm->len > gsm->mru) {
@@ -2889,14 +2916,14 @@ static void gsm0_receive(struct gsm_mux *gsm, u8 c)
}
gsm->count = 0;
if (!gsm->len)
- gsm->state = GSM_FCS;
+ gsm->state = GSM0_FCS;
else
- gsm->state = GSM_DATA;
+ gsm->state = GSM0_DATA;
break;
}
- gsm->state = GSM_LEN1;
+ gsm->state = GSM0_LEN1;
break;
- case GSM_LEN1:
+ case GSM0_LEN1:
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
len = c;
gsm->len |= len << 7;
@@ -2907,26 +2934,29 @@ static void gsm0_receive(struct gsm_mux *gsm, u8 c)
}
gsm->count = 0;
if (!gsm->len)
- gsm->state = GSM_FCS;
+ gsm->state = GSM0_FCS;
else
- gsm->state = GSM_DATA;
+ gsm->state = GSM0_DATA;
break;
- case GSM_DATA: /* Data */
+ case GSM0_DATA: /* Data */
gsm->buf[gsm->count++] = c;
- if (gsm->count == gsm->len) {
+ if (gsm->count >= MAX_MRU) {
+ gsm->bad_size++;
+ gsm->state = GSM_SEARCH;
+ } else if (gsm->count >= gsm->len) {
/* Calculate final FCS for UI frames over all data */
if ((gsm->control & ~PF) != UIH) {
gsm->fcs = gsm_fcs_add_block(gsm->fcs, gsm->buf,
gsm->count);
}
- gsm->state = GSM_FCS;
+ gsm->state = GSM0_FCS;
}
break;
- case GSM_FCS: /* FCS follows the packet */
+ case GSM0_FCS: /* FCS follows the packet */
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
- gsm->state = GSM_SSOF;
+ gsm->state = GSM0_SSOF;
break;
- case GSM_SSOF:
+ case GSM0_SSOF:
gsm->state = GSM_SEARCH;
if (c == GSM0_SOF)
gsm_queue(gsm);
@@ -2940,6 +2970,29 @@ static void gsm0_receive(struct gsm_mux *gsm, u8 c)
}
/**
+ * gsm1_receive_state_check_and_fix - check and correct receive state
+ * @gsm: gsm data for this ldisc instance
+ *
+ * Ensures that the current receive state is valid for advanced option mode.
+ */
+
+static void gsm1_receive_state_check_and_fix(struct gsm_mux *gsm)
+{
+ switch (gsm->state) {
+ case GSM_SEARCH:
+ case GSM1_START:
+ case GSM1_ADDRESS:
+ case GSM1_CONTROL:
+ case GSM1_DATA:
+ case GSM1_OVERRUN:
+ break;
+ default:
+ gsm->state = GSM_SEARCH;
+ break;
+ }
+}
+
+/**
* gsm1_receive - perform processing for non-transparency
* @gsm: gsm data for this ldisc instance
* @c: character
@@ -2949,6 +3002,7 @@ static void gsm0_receive(struct gsm_mux *gsm, u8 c)
static void gsm1_receive(struct gsm_mux *gsm, u8 c)
{
+ gsm1_receive_state_check_and_fix(gsm);
/* handle XON/XOFF */
if ((c & ISO_IEC_646_MASK) == XON) {
gsm->constipated = true;
@@ -2961,11 +3015,11 @@ static void gsm1_receive(struct gsm_mux *gsm, u8 c)
}
if (c == GSM1_SOF) {
/* EOF is only valid in frame if we have got to the data state */
- if (gsm->state == GSM_DATA) {
+ if (gsm->state == GSM1_DATA) {
if (gsm->count < 1) {
/* Missing FSC */
gsm->malformed++;
- gsm->state = GSM_START;
+ gsm->state = GSM1_START;
return;
}
/* Remove the FCS from data */
@@ -2981,14 +3035,14 @@ static void gsm1_receive(struct gsm_mux *gsm, u8 c)
gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->buf[gsm->count]);
gsm->len = gsm->count;
gsm_queue(gsm);
- gsm->state = GSM_START;
+ gsm->state = GSM1_START;
return;
}
/* Any partial frame was a runt so go back to start */
- if (gsm->state != GSM_START) {
+ if (gsm->state != GSM1_START) {
if (gsm->state != GSM_SEARCH)
gsm->malformed++;
- gsm->state = GSM_START;
+ gsm->state = GSM1_START;
}
/* A SOF in GSM_START means we are still reading idling or
framing bytes */
@@ -3009,30 +3063,30 @@ static void gsm1_receive(struct gsm_mux *gsm, u8 c)
gsm->escape = false;
}
switch (gsm->state) {
- case GSM_START: /* First byte after SOF */
+ case GSM1_START: /* First byte after SOF */
gsm->address = 0;
- gsm->state = GSM_ADDRESS;
+ gsm->state = GSM1_ADDRESS;
gsm->fcs = INIT_FCS;
fallthrough;
- case GSM_ADDRESS: /* Address continuation */
+ case GSM1_ADDRESS: /* Address continuation */
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
if (gsm_read_ea(&gsm->address, c))
- gsm->state = GSM_CONTROL;
+ gsm->state = GSM1_CONTROL;
break;
- case GSM_CONTROL: /* Control Byte */
+ case GSM1_CONTROL: /* Control Byte */
gsm->fcs = gsm_fcs_add(gsm->fcs, c);
gsm->control = c;
gsm->count = 0;
- gsm->state = GSM_DATA;
+ gsm->state = GSM1_DATA;
break;
- case GSM_DATA: /* Data */
- if (gsm->count > gsm->mru) { /* Allow one for the FCS */
- gsm->state = GSM_OVERRUN;
+ case GSM1_DATA: /* Data */
+ if (gsm->count > gsm->mru || gsm->count > MAX_MRU) { /* Allow one for the FCS */
+ gsm->state = GSM1_OVERRUN;
gsm->bad_size++;
} else
gsm->buf[gsm->count++] = c;
break;
- case GSM_OVERRUN: /* Over-long - eg a dropped SOF */
+ case GSM1_OVERRUN: /* Over-long - eg a dropped SOF */
break;
default:
pr_debug("%s: unhandled state: %d\n", __func__, gsm->state);
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-12 14:58:12 +0000