/*
* State machine for state 2, Awaiting Release State.
* The handling of the timer(s) is in file lapb_timer.c
*/
static void lapb_state2_machine(struct lapb_cb *lapb, struct sk_buff *skb,
struct lapb_frame *frame)
{
switch (frame->type) {
case LAPB_SABM:
case LAPB_SABME:
lapb_dbg(1, "(%p) S2 RX {SABM,SABME}(%d)\n",
lapb->dev, frame->pf);
lapb_dbg(1, "(%p) S2 TX DM(%d)\n", lapb->dev, frame->pf);
lapb_send_control(lapb, LAPB_DM, frame->pf, LAPB_RESPONSE);
break;
case LAPB_DISC:
lapb_dbg(1, "(%p) S2 RX DISC(%d)\n", lapb->dev, frame->pf);
lapb_dbg(1, "(%p) S2 TX UA(%d)\n", lapb->dev, frame->pf);
lapb_send_control(lapb, LAPB_UA, frame->pf, LAPB_RESPONSE);
break;
case LAPB_UA:
lapb_dbg(1, "(%p) S2 RX UA(%d)\n", lapb->dev, frame->pf);
if (frame->pf) {
lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev);
lapb->state = LAPB_STATE_0;
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb_disconnect_confirmation(lapb, LAPB_OK);
}
break;
case LAPB_DM:
lapb_dbg(1, "(%p) S2 RX DM(%d)\n", lapb->dev, frame->pf);
if (frame->pf) {
lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev);
lapb->state = LAPB_STATE_0;
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb_disconnect_confirmation(lapb, LAPB_NOTCONNECTED);
}
break;
case LAPB_I:
case LAPB_REJ:
case LAPB_RNR:
case LAPB_RR:
lapb_dbg(1, "(%p) S2 RX {I,REJ,RNR,RR}(%d)\n",
lapb->dev, frame->pf);
lapb_dbg(1, "(%p) S2 RX DM(%d)\n", lapb->dev, frame->pf);
if (frame->pf)
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
break;
}
kfree_skb(skb);
}
/*
* This procedure is passed a buffer descriptor for an iframe. It builds
* the rest of the control part of the frame and then writes it out.
*/
static void lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit)
{
unsigned char *frame;
if (!skb)
return;
if (lapb->mode & LAPB_EXTENDED) {
frame = skb_push(skb, 2);
frame[0] = LAPB_I;
frame[0] |= lapb->vs << 1;
frame[1] = poll_bit ? LAPB_EPF : 0;
frame[1] |= lapb->vr << 1;
} else {
frame = skb_push(skb, 1);
*frame = LAPB_I;
*frame |= poll_bit ? LAPB_SPF : 0;
*frame |= lapb->vr << 5;
*frame |= lapb->vs << 1;
}
lapb_dbg(1, "(%p) S%d TX I(%d) S%d R%d\n",
lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr);
lapb_transmit_buffer(lapb, skb, LAPB_COMMAND);
}
void lapb_establish_data_link(struct lapb_cb *lapb)
{
lapb->condition = 0x00;
lapb->n2count = 0;
if (lapb->mode & LAPB_EXTENDED) {
lapb_dbg(1, "(%p) S%d TX SABME(1)\n", lapb->dev, lapb->state);
lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
} else {
lapb_dbg(1, "(%p) S%d TX SABM(1)\n", lapb->dev, lapb->state);
lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
}
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
}
/*
* State machine for state 4, Frame Reject State.
* The handling of the timer(s) is in file lapb_timer.c.
*/
static void lapb_state4_machine(struct lapb_cb *lapb, struct sk_buff *skb,
struct lapb_frame *frame)
{
switch (frame->type) {
case LAPB_SABM:
lapb_dbg(1, "(%p) S4 RX SABM(%d)\n", lapb->dev, frame->pf);
if (lapb->mode & LAPB_EXTENDED) {
lapb_dbg(1, "(%p) S4 TX DM(%d)\n",
lapb->dev, frame->pf);
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
} else {
lapb_dbg(1, "(%p) S4 TX UA(%d)\n",
lapb->dev, frame->pf);
lapb_dbg(0, "(%p) S4 -> S3\n", lapb->dev);
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_3;
lapb->condition = 0x00;
lapb->n2count = 0;
lapb->vs = 0;
lapb->vr = 0;
lapb->va = 0;
lapb_connect_indication(lapb, LAPB_OK);
}
break;
case LAPB_SABME:
lapb_dbg(1, "(%p) S4 RX SABME(%d)\n", lapb->dev, frame->pf);
if (lapb->mode & LAPB_EXTENDED) {
lapb_dbg(1, "(%p) S4 TX UA(%d)\n",
lapb->dev, frame->pf);
lapb_dbg(0, "(%p) S4 -> S3\n", lapb->dev);
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_3;
lapb->condition = 0x00;
lapb->n2count = 0;
lapb->vs = 0;
lapb->vr = 0;
lapb->va = 0;
lapb_connect_indication(lapb, LAPB_OK);
} else {
lapb_dbg(1, "(%p) S4 TX DM(%d)\n",
lapb->dev, frame->pf);
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
}
break;
}
kfree_skb(skb);
}
void lapb_timeout_response(struct lapb_cb *lapb)
{
lapb_dbg(1, "(%p) S%d TX RR(0) R%d\n",
lapb->dev, lapb->state, lapb->vr);
lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE);
lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
}
void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *skb, int type)
{
unsigned char *ptr;
ptr = skb_push(skb, 1);
if (lapb->mode & LAPB_MLP) {
if (lapb->mode & LAPB_DCE) {
if (type == LAPB_COMMAND)
*ptr = LAPB_ADDR_C;
if (type == LAPB_RESPONSE)
*ptr = LAPB_ADDR_D;
} else {
if (type == LAPB_COMMAND)
*ptr = LAPB_ADDR_D;
if (type == LAPB_RESPONSE)
*ptr = LAPB_ADDR_C;
}
} else {
if (lapb->mode & LAPB_DCE) {
if (type == LAPB_COMMAND)
*ptr = LAPB_ADDR_A;
if (type == LAPB_RESPONSE)
*ptr = LAPB_ADDR_B;
} else {
if (type == LAPB_COMMAND)
*ptr = LAPB_ADDR_B;
if (type == LAPB_RESPONSE)
*ptr = LAPB_ADDR_A;
}
}
lapb_dbg(2, "(%p) S%d TX %02X %02X %02X\n",
lapb->dev, lapb->state,
skb->data[0], skb->data[1], skb->data[2]);
if (!lapb_data_transmit(lapb, skb))
kfree_skb(skb);
}
/*
* State machine for state 3, Connected State.
* The handling of the timer(s) is in file lapb_timer.c
*/
static void lapb_state3_machine(struct lapb_cb *lapb, struct sk_buff *skb,
struct lapb_frame *frame)
{
int queued = 0;
int modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS :
LAPB_SMODULUS;
switch (frame->type) {
case LAPB_SABM:
lapb_dbg(1, "(%p) S3 RX SABM(%d)\n", lapb->dev, frame->pf);
if (lapb->mode & LAPB_EXTENDED) {
lapb_dbg(1, "(%p) S3 TX DM(%d)\n",
lapb->dev, frame->pf);
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
} else {
lapb_dbg(1, "(%p) S3 TX UA(%d)\n",
lapb->dev, frame->pf);
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->condition = 0x00;
lapb->n2count = 0;
lapb->vs = 0;
lapb->vr = 0;
lapb->va = 0;
lapb_requeue_frames(lapb);
}
break;
case LAPB_SABME:
lapb_dbg(1, "(%p) S3 RX SABME(%d)\n", lapb->dev, frame->pf);
if (lapb->mode & LAPB_EXTENDED) {
lapb_dbg(1, "(%p) S3 TX UA(%d)\n",
lapb->dev, frame->pf);
lapb_send_control(lapb, LAPB_UA, frame->pf,
LAPB_RESPONSE);
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->condition = 0x00;
lapb->n2count = 0;
lapb->vs = 0;
lapb->vr = 0;
lapb->va = 0;
lapb_requeue_frames(lapb);
} else {
lapb_dbg(1, "(%p) S3 TX DM(%d)\n",
lapb->dev, frame->pf);
lapb_send_control(lapb, LAPB_DM, frame->pf,
LAPB_RESPONSE);
}
break;
case LAPB_DISC:
lapb_dbg(1, "(%p) S3 RX DISC(%d)\n", lapb->dev, frame->pf);
lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev);
lapb_clear_queues(lapb);
lapb_send_control(lapb, LAPB_UA, frame->pf, LAPB_RESPONSE);
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_0;
lapb_disconnect_indication(lapb, LAPB_OK);
break;
case LAPB_DM:
lapb_dbg(1, "(%p) S3 RX DM(%d)\n", lapb->dev, frame->pf);
lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev);
lapb_clear_queues(lapb);
lapb->state = LAPB_STATE_0;
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb_disconnect_indication(lapb, LAPB_NOTCONNECTED);
break;
case LAPB_RNR:
lapb_dbg(1, "(%p) S3 RX RNR(%d) R%d\n",
lapb->dev, frame->pf, frame->nr);
lapb->condition |= LAPB_PEER_RX_BUSY_CONDITION;
lapb_check_need_response(lapb, frame->cr, frame->pf);
if (lapb_validate_nr(lapb, frame->nr)) {
lapb_check_iframes_acked(lapb, frame->nr);
} else {
lapb->frmr_data = *frame;
lapb->frmr_type = LAPB_FRMR_Z;
lapb_transmit_frmr(lapb);
lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev);
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_4;
lapb->n2count = 0;
}
break;
case LAPB_RR:
lapb_dbg(1, "(%p) S3 RX RR(%d) R%d\n",
lapb->dev, frame->pf, frame->nr);
lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
lapb_check_need_response(lapb, frame->cr, frame->pf);
if (lapb_validate_nr(lapb, frame->nr)) {
lapb_check_iframes_acked(lapb, frame->nr);
} else {
lapb->frmr_data = *frame;
lapb->frmr_type = LAPB_FRMR_Z;
lapb_transmit_frmr(lapb);
lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev);
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_4;
lapb->n2count = 0;
}
break;
case LAPB_REJ:
lapb_dbg(1, "(%p) S3 RX REJ(%d) R%d\n",
lapb->dev, frame->pf, frame->nr);
lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
lapb_check_need_response(lapb, frame->cr, frame->pf);
if (lapb_validate_nr(lapb, frame->nr)) {
lapb_frames_acked(lapb, frame->nr);
lapb_stop_t1timer(lapb);
lapb->n2count = 0;
lapb_requeue_frames(lapb);
} else {
lapb->frmr_data = *frame;
lapb->frmr_type = LAPB_FRMR_Z;
lapb_transmit_frmr(lapb);
lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev);
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_4;
lapb->n2count = 0;
}
break;
case LAPB_I:
lapb_dbg(1, "(%p) S3 RX I(%d) S%d R%d\n",
lapb->dev, frame->pf, frame->ns, frame->nr);
if (!lapb_validate_nr(lapb, frame->nr)) {
lapb->frmr_data = *frame;
lapb->frmr_type = LAPB_FRMR_Z;
lapb_transmit_frmr(lapb);
lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev);
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_4;
lapb->n2count = 0;
break;
}
if (lapb->condition & LAPB_PEER_RX_BUSY_CONDITION)
lapb_frames_acked(lapb, frame->nr);
else
lapb_check_iframes_acked(lapb, frame->nr);
if (frame->ns == lapb->vr) {
int cn;
cn = lapb_data_indication(lapb, skb);
queued = 1;
/*
* If upper layer has dropped the frame, we
* basically ignore any further protocol
* processing. This will cause the peer
* to re-transmit the frame later like
* a frame lost on the wire.
*/
if (cn == NET_RX_DROP) {
pr_debug("rx congestion\n");
break;
}
lapb->vr = (lapb->vr + 1) % modulus;
lapb->condition &= ~LAPB_REJECT_CONDITION;
if (frame->pf)
lapb_enquiry_response(lapb);
else {
if (!(lapb->condition &
LAPB_ACK_PENDING_CONDITION)) {
lapb->condition |= LAPB_ACK_PENDING_CONDITION;
lapb_start_t2timer(lapb);
}
}
} else {
if (lapb->condition & LAPB_REJECT_CONDITION) {
if (frame->pf)
lapb_enquiry_response(lapb);
} else {
lapb_dbg(1, "(%p) S3 TX REJ(%d) R%d\n",
lapb->dev, frame->pf, lapb->vr);
lapb->condition |= LAPB_REJECT_CONDITION;
lapb_send_control(lapb, LAPB_REJ, frame->pf,
LAPB_RESPONSE);
lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
}
}
break;
case LAPB_FRMR:
lapb_dbg(1, "(%p) S3 RX FRMR(%d) %5ph\n",
lapb->dev, frame->pf,
skb->data);
lapb_establish_data_link(lapb);
lapb_dbg(0, "(%p) S3 -> S1\n", lapb->dev);
lapb_requeue_frames(lapb);
lapb->state = LAPB_STATE_1;
break;
case LAPB_ILLEGAL:
lapb_dbg(1, "(%p) S3 RX ILLEGAL(%d)\n", lapb->dev, frame->pf);
lapb->frmr_data = *frame;
lapb->frmr_type = LAPB_FRMR_W;
lapb_transmit_frmr(lapb);
lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev);
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_4;
lapb->n2count = 0;
break;
}
if (!queued)
kfree_skb(skb);
}
/*
* This routine is the centralised routine for parsing the control
* information for the different frame formats.
*/
int lapb_decode(struct lapb_cb *lapb, struct sk_buff *skb,
struct lapb_frame *frame)
{
frame->type = LAPB_ILLEGAL;
lapb_dbg(2, "(%p) S%d RX %3ph\n", lapb->dev, lapb->state, skb->data);
/* We always need to look at 2 bytes, sometimes we need
* to look at 3 and those cases are handled below.
*/
if (!pskb_may_pull(skb, 2))
return -1;
if (lapb->mode & LAPB_MLP) {
if (lapb->mode & LAPB_DCE) {
if (skb->data[0] == LAPB_ADDR_D)
frame->cr = LAPB_COMMAND;
if (skb->data[0] == LAPB_ADDR_C)
frame->cr = LAPB_RESPONSE;
} else {
if (skb->data[0] == LAPB_ADDR_C)
frame->cr = LAPB_COMMAND;
if (skb->data[0] == LAPB_ADDR_D)
frame->cr = LAPB_RESPONSE;
}
} else {
if (lapb->mode & LAPB_DCE) {
if (skb->data[0] == LAPB_ADDR_B)
frame->cr = LAPB_COMMAND;
if (skb->data[0] == LAPB_ADDR_A)
frame->cr = LAPB_RESPONSE;
} else {
if (skb->data[0] == LAPB_ADDR_A)
frame->cr = LAPB_COMMAND;
if (skb->data[0] == LAPB_ADDR_B)
frame->cr = LAPB_RESPONSE;
}
}
skb_pull(skb, 1);
if (lapb->mode & LAPB_EXTENDED) {
if (!(skb->data[0] & LAPB_S)) {
if (!pskb_may_pull(skb, 2))
return -1;
/*
* I frame - carries NR/NS/PF
*/
frame->type = LAPB_I;
frame->ns = (skb->data[0] >> 1) & 0x7F;
frame->nr = (skb->data[1] >> 1) & 0x7F;
frame->pf = skb->data[1] & LAPB_EPF;
frame->control[0] = skb->data[0];
frame->control[1] = skb->data[1];
skb_pull(skb, 2);
} else if ((skb->data[0] & LAPB_U) == 1) {
if (!pskb_may_pull(skb, 2))
return -1;
/*
* S frame - take out PF/NR
*/
frame->type = skb->data[0] & 0x0F;
frame->nr = (skb->data[1] >> 1) & 0x7F;
frame->pf = skb->data[1] & LAPB_EPF;
frame->control[0] = skb->data[0];
frame->control[1] = skb->data[1];
skb_pull(skb, 2);
} else if ((skb->data[0] & LAPB_U) == 3) {
