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-rw-r--r--net/x25/x25_in.c456
1 files changed, 456 insertions, 0 deletions
diff --git a/net/x25/x25_in.c b/net/x25/x25_in.c
new file mode 100644
index 000000000..b981a4828
--- /dev/null
+++ b/net/x25/x25_in.c
@@ -0,0 +1,456 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * X.25 Packet Layer release 002
+ *
+ * This is ALPHA test software. This code may break your machine,
+ * randomly fail to work with new releases, misbehave and/or generally
+ * screw up. It might even work.
+ *
+ * This code REQUIRES 2.1.15 or higher
+ *
+ * History
+ * X.25 001 Jonathan Naylor Started coding.
+ * X.25 002 Jonathan Naylor Centralised disconnection code.
+ * New timer architecture.
+ * 2000-03-20 Daniela Squassoni Disabling/enabling of facilities
+ * negotiation.
+ * 2000-11-10 Henner Eisen Check and reset for out-of-sequence
+ * i-frames.
+ */
+
+#define pr_fmt(fmt) "X25: " fmt
+
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <net/x25.h>
+
+static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
+{
+ struct sk_buff *skbo, *skbn = skb;
+ struct x25_sock *x25 = x25_sk(sk);
+
+ if (more) {
+ x25->fraglen += skb->len;
+ skb_queue_tail(&x25->fragment_queue, skb);
+ skb_set_owner_r(skb, sk);
+ return 0;
+ }
+
+ if (x25->fraglen > 0) { /* End of fragment */
+ int len = x25->fraglen + skb->len;
+
+ if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
+ kfree_skb(skb);
+ return 1;
+ }
+
+ skb_queue_tail(&x25->fragment_queue, skb);
+
+ skb_reset_transport_header(skbn);
+
+ skbo = skb_dequeue(&x25->fragment_queue);
+ skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),
+ skbo->len);
+ kfree_skb(skbo);
+
+ while ((skbo =
+ skb_dequeue(&x25->fragment_queue)) != NULL) {
+ skb_pull(skbo, (x25->neighbour->extended) ?
+ X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
+ skb_copy_from_linear_data(skbo,
+ skb_put(skbn, skbo->len),
+ skbo->len);
+ kfree_skb(skbo);
+ }
+
+ x25->fraglen = 0;
+ }
+
+ skb_set_owner_r(skbn, sk);
+ skb_queue_tail(&sk->sk_receive_queue, skbn);
+ if (!sock_flag(sk, SOCK_DEAD))
+ sk->sk_data_ready(sk);
+
+ return 0;
+}
+
+/*
+ * State machine for state 1, Awaiting Call Accepted State.
+ * The handling of the timer(s) is in file x25_timer.c.
+ * Handling of state 0 and connection release is in af_x25.c.
+ */
+static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
+{
+ struct x25_address source_addr, dest_addr;
+ int len;
+ struct x25_sock *x25 = x25_sk(sk);
+
+ switch (frametype) {
+ case X25_CALL_ACCEPTED: {
+
+ x25_stop_timer(sk);
+ x25->condition = 0x00;
+ x25->vs = 0;
+ x25->va = 0;
+ x25->vr = 0;
+ x25->vl = 0;
+ x25->state = X25_STATE_3;
+ sk->sk_state = TCP_ESTABLISHED;
+ /*
+ * Parse the data in the frame.
+ */
+ if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
+ goto out_clear;
+ skb_pull(skb, X25_STD_MIN_LEN);
+
+ len = x25_parse_address_block(skb, &source_addr,
+ &dest_addr);
+ if (len > 0)
+ skb_pull(skb, len);
+ else if (len < 0)
+ goto out_clear;
+
+ len = x25_parse_facilities(skb, &x25->facilities,
+ &x25->dte_facilities,
+ &x25->vc_facil_mask);
+ if (len > 0)
+ skb_pull(skb, len);
+ else if (len < 0)
+ goto out_clear;
+ /*
+ * Copy any Call User Data.
+ */
+ if (skb->len > 0) {
+ if (skb->len > X25_MAX_CUD_LEN)
+ goto out_clear;
+
+ skb_copy_bits(skb, 0, x25->calluserdata.cuddata,
+ skb->len);
+ x25->calluserdata.cudlength = skb->len;
+ }
+ if (!sock_flag(sk, SOCK_DEAD))
+ sk->sk_state_change(sk);
+ break;
+ }
+ case X25_CALL_REQUEST:
+ /* call collision */
+ x25->causediag.cause = 0x01;
+ x25->causediag.diagnostic = 0x48;
+
+ x25_write_internal(sk, X25_CLEAR_REQUEST);
+ x25_disconnect(sk, EISCONN, 0x01, 0x48);
+ break;
+
+ case X25_CLEAR_REQUEST:
+ if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
+ goto out_clear;
+
+ x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
+ x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
+ break;
+
+ default:
+ break;
+ }
+
+ return 0;
+
+out_clear:
+ x25_write_internal(sk, X25_CLEAR_REQUEST);
+ x25->state = X25_STATE_2;
+ x25_start_t23timer(sk);
+ return 0;
+}
+
+/*
+ * State machine for state 2, Awaiting Clear Confirmation State.
+ * The handling of the timer(s) is in file x25_timer.c
+ * Handling of state 0 and connection release is in af_x25.c.
+ */
+static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
+{
+ switch (frametype) {
+
+ case X25_CLEAR_REQUEST:
+ if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
+ goto out_clear;
+
+ x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
+ x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
+ break;
+
+ case X25_CLEAR_CONFIRMATION:
+ x25_disconnect(sk, 0, 0, 0);
+ break;
+
+ default:
+ break;
+ }
+
+ return 0;
+
+out_clear:
+ x25_write_internal(sk, X25_CLEAR_REQUEST);
+ x25_start_t23timer(sk);
+ return 0;
+}
+
+/*
+ * State machine for state 3, Connected State.
+ * The handling of the timer(s) is in file x25_timer.c
+ * Handling of state 0 and connection release is in af_x25.c.
+ */
+static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
+{
+ int queued = 0;
+ int modulus;
+ struct x25_sock *x25 = x25_sk(sk);
+
+ modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
+
+ switch (frametype) {
+
+ case X25_RESET_REQUEST:
+ x25_write_internal(sk, X25_RESET_CONFIRMATION);
+ x25_stop_timer(sk);
+ x25->condition = 0x00;
+ x25->vs = 0;
+ x25->vr = 0;
+ x25->va = 0;
+ x25->vl = 0;
+ x25_requeue_frames(sk);
+ break;
+
+ case X25_CLEAR_REQUEST:
+ if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
+ goto out_clear;
+
+ x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
+ x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
+ break;
+
+ case X25_RR:
+ case X25_RNR:
+ if (!x25_validate_nr(sk, nr)) {
+ x25_clear_queues(sk);
+ x25_write_internal(sk, X25_RESET_REQUEST);
+ x25_start_t22timer(sk);
+ x25->condition = 0x00;
+ x25->vs = 0;
+ x25->vr = 0;
+ x25->va = 0;
+ x25->vl = 0;
+ x25->state = X25_STATE_4;
+ } else {
+ x25_frames_acked(sk, nr);
+ if (frametype == X25_RNR) {
+ x25->condition |= X25_COND_PEER_RX_BUSY;
+ } else {
+ x25->condition &= ~X25_COND_PEER_RX_BUSY;
+ }
+ }
+ break;
+
+ case X25_DATA: /* XXX */
+ x25->condition &= ~X25_COND_PEER_RX_BUSY;
+ if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
+ x25_clear_queues(sk);
+ x25_write_internal(sk, X25_RESET_REQUEST);
+ x25_start_t22timer(sk);
+ x25->condition = 0x00;
+ x25->vs = 0;
+ x25->vr = 0;
+ x25->va = 0;
+ x25->vl = 0;
+ x25->state = X25_STATE_4;
+ break;
+ }
+ x25_frames_acked(sk, nr);
+ if (ns == x25->vr) {
+ if (x25_queue_rx_frame(sk, skb, m) == 0) {
+ x25->vr = (x25->vr + 1) % modulus;
+ queued = 1;
+ } else {
+ /* Should never happen */
+ x25_clear_queues(sk);
+ x25_write_internal(sk, X25_RESET_REQUEST);
+ x25_start_t22timer(sk);
+ x25->condition = 0x00;
+ x25->vs = 0;
+ x25->vr = 0;
+ x25->va = 0;
+ x25->vl = 0;
+ x25->state = X25_STATE_4;
+ break;
+ }
+ if (atomic_read(&sk->sk_rmem_alloc) >
+ (sk->sk_rcvbuf >> 1))
+ x25->condition |= X25_COND_OWN_RX_BUSY;
+ }
+ /*
+ * If the window is full Ack it immediately, else
+ * start the holdback timer.
+ */
+ if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
+ x25->condition &= ~X25_COND_ACK_PENDING;
+ x25_stop_timer(sk);
+ x25_enquiry_response(sk);
+ } else {
+ x25->condition |= X25_COND_ACK_PENDING;
+ x25_start_t2timer(sk);
+ }
+ break;
+
+ case X25_INTERRUPT_CONFIRMATION:
+ clear_bit(X25_INTERRUPT_FLAG, &x25->flags);
+ break;
+
+ case X25_INTERRUPT:
+ if (sock_flag(sk, SOCK_URGINLINE))
+ queued = !sock_queue_rcv_skb(sk, skb);
+ else {
+ skb_set_owner_r(skb, sk);
+ skb_queue_tail(&x25->interrupt_in_queue, skb);
+ queued = 1;
+ }
+ sk_send_sigurg(sk);
+ x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
+ break;
+
+ default:
+ pr_warn("unknown %02X in state 3\n", frametype);
+ break;
+ }
+
+ return queued;
+
+out_clear:
+ x25_write_internal(sk, X25_CLEAR_REQUEST);
+ x25->state = X25_STATE_2;
+ x25_start_t23timer(sk);
+ return 0;
+}
+
+/*
+ * State machine for state 4, Awaiting Reset Confirmation State.
+ * The handling of the timer(s) is in file x25_timer.c
+ * Handling of state 0 and connection release is in af_x25.c.
+ */
+static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
+{
+ struct x25_sock *x25 = x25_sk(sk);
+
+ switch (frametype) {
+
+ case X25_RESET_REQUEST:
+ x25_write_internal(sk, X25_RESET_CONFIRMATION);
+ fallthrough;
+ case X25_RESET_CONFIRMATION: {
+ x25_stop_timer(sk);
+ x25->condition = 0x00;
+ x25->va = 0;
+ x25->vr = 0;
+ x25->vs = 0;
+ x25->vl = 0;
+ x25->state = X25_STATE_3;
+ x25_requeue_frames(sk);
+ break;
+ }
+ case X25_CLEAR_REQUEST:
+ if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
+ goto out_clear;
+
+ x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
+ x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
+ break;
+
+ default:
+ break;
+ }
+
+ return 0;
+
+out_clear:
+ x25_write_internal(sk, X25_CLEAR_REQUEST);
+ x25->state = X25_STATE_2;
+ x25_start_t23timer(sk);
+ return 0;
+}
+
+/*
+ * State machine for state 5, Call Accepted / Call Connected pending (X25_ACCPT_APPRV_FLAG).
+ * The handling of the timer(s) is in file x25_timer.c
+ * Handling of state 0 and connection release is in af_x25.c.
+ */
+static int x25_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype)
+{
+ struct x25_sock *x25 = x25_sk(sk);
+
+ switch (frametype) {
+ case X25_CLEAR_REQUEST:
+ if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) {
+ x25_write_internal(sk, X25_CLEAR_REQUEST);
+ x25->state = X25_STATE_2;
+ x25_start_t23timer(sk);
+ return 0;
+ }
+
+ x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
+ x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
+ break;
+
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+/* Higher level upcall for a LAPB frame */
+int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
+{
+ struct x25_sock *x25 = x25_sk(sk);
+ int queued = 0, frametype, ns, nr, q, d, m;
+
+ if (x25->state == X25_STATE_0)
+ return 0;
+
+ frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
+
+ switch (x25->state) {
+ case X25_STATE_1:
+ queued = x25_state1_machine(sk, skb, frametype);
+ break;
+ case X25_STATE_2:
+ queued = x25_state2_machine(sk, skb, frametype);
+ break;
+ case X25_STATE_3:
+ queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
+ break;
+ case X25_STATE_4:
+ queued = x25_state4_machine(sk, skb, frametype);
+ break;
+ case X25_STATE_5:
+ queued = x25_state5_machine(sk, skb, frametype);
+ break;
+ }
+
+ x25_kick(sk);
+
+ return queued;
+}
+
+int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
+{
+ int queued = x25_process_rx_frame(sk, skb);
+
+ if (!queued)
+ kfree_skb(skb);
+
+ return 0;
+}
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