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-rw-r--r--net/x25/x25_subr.c384
1 files changed, 384 insertions, 0 deletions
diff --git a/net/x25/x25_subr.c b/net/x25/x25_subr.c
new file mode 100644
index 000000000..0285aaa1e
--- /dev/null
+++ b/net/x25/x25_subr.c
@@ -0,0 +1,384 @@
+// 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 processing.
+ * mar/20/00 Daniela Squassoni Disabling/enabling of facilities
+ * negotiation.
+ * jun/24/01 Arnaldo C. Melo use skb_queue_purge, cleanups
+ * apr/04/15 Shaun Pereira Fast select with no
+ * restriction on response.
+ */
+
+#define pr_fmt(fmt) "X25: " fmt
+
+#include <linux/slab.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>
+
+/*
+ * This routine purges all of the queues of frames.
+ */
+void x25_clear_queues(struct sock *sk)
+{
+ struct x25_sock *x25 = x25_sk(sk);
+
+ skb_queue_purge(&sk->sk_write_queue);
+ skb_queue_purge(&x25->ack_queue);
+ skb_queue_purge(&x25->interrupt_in_queue);
+ skb_queue_purge(&x25->interrupt_out_queue);
+ skb_queue_purge(&x25->fragment_queue);
+}
+
+
+/*
+ * This routine purges the input queue of those frames that have been
+ * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
+ * SDL diagram.
+*/
+void x25_frames_acked(struct sock *sk, unsigned short nr)
+{
+ struct sk_buff *skb;
+ struct x25_sock *x25 = x25_sk(sk);
+ int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
+
+ /*
+ * Remove all the ack-ed frames from the ack queue.
+ */
+ if (x25->va != nr)
+ while (skb_peek(&x25->ack_queue) && x25->va != nr) {
+ skb = skb_dequeue(&x25->ack_queue);
+ kfree_skb(skb);
+ x25->va = (x25->va + 1) % modulus;
+ }
+}
+
+void x25_requeue_frames(struct sock *sk)
+{
+ struct sk_buff *skb, *skb_prev = NULL;
+
+ /*
+ * Requeue all the un-ack-ed frames on the output queue to be picked
+ * up by x25_kick. This arrangement handles the possibility of an empty
+ * output queue.
+ */
+ while ((skb = skb_dequeue(&x25_sk(sk)->ack_queue)) != NULL) {
+ if (!skb_prev)
+ skb_queue_head(&sk->sk_write_queue, skb);
+ else
+ skb_append(skb_prev, skb, &sk->sk_write_queue);
+ skb_prev = skb;
+ }
+}
+
+/*
+ * Validate that the value of nr is between va and vs. Return true or
+ * false for testing.
+ */
+int x25_validate_nr(struct sock *sk, unsigned short nr)
+{
+ struct x25_sock *x25 = x25_sk(sk);
+ unsigned short vc = x25->va;
+ int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
+
+ while (vc != x25->vs) {
+ if (nr == vc)
+ return 1;
+ vc = (vc + 1) % modulus;
+ }
+
+ return nr == x25->vs ? 1 : 0;
+}
+
+/*
+ * This routine is called when the packet layer internally generates a
+ * control frame.
+ */
+void x25_write_internal(struct sock *sk, int frametype)
+{
+ struct x25_sock *x25 = x25_sk(sk);
+ struct sk_buff *skb;
+ unsigned char *dptr;
+ unsigned char facilities[X25_MAX_FAC_LEN];
+ unsigned char addresses[1 + X25_ADDR_LEN];
+ unsigned char lci1, lci2;
+ /*
+ * Default safe frame size.
+ */
+ int len = X25_MAX_L2_LEN + X25_EXT_MIN_LEN;
+
+ /*
+ * Adjust frame size.
+ */
+ switch (frametype) {
+ case X25_CALL_REQUEST:
+ len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
+ break;
+ case X25_CALL_ACCEPTED: /* fast sel with no restr on resp */
+ if (x25->facilities.reverse & 0x80) {
+ len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
+ } else {
+ len += 1 + X25_MAX_FAC_LEN;
+ }
+ break;
+ case X25_CLEAR_REQUEST:
+ case X25_RESET_REQUEST:
+ len += 2;
+ break;
+ case X25_RR:
+ case X25_RNR:
+ case X25_REJ:
+ case X25_CLEAR_CONFIRMATION:
+ case X25_INTERRUPT_CONFIRMATION:
+ case X25_RESET_CONFIRMATION:
+ break;
+ default:
+ pr_err("invalid frame type %02X\n", frametype);
+ return;
+ }
+
+ if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
+ return;
+
+ /*
+ * Space for Ethernet and 802.2 LLC headers.
+ */
+ skb_reserve(skb, X25_MAX_L2_LEN);
+
+ /*
+ * Make space for the GFI and LCI, and fill them in.
+ */
+ dptr = skb_put(skb, 2);
+
+ lci1 = (x25->lci >> 8) & 0x0F;
+ lci2 = (x25->lci >> 0) & 0xFF;
+
+ if (x25->neighbour->extended) {
+ *dptr++ = lci1 | X25_GFI_EXTSEQ;
+ *dptr++ = lci2;
+ } else {
+ *dptr++ = lci1 | X25_GFI_STDSEQ;
+ *dptr++ = lci2;
+ }
+
+ /*
+ * Now fill in the frame type specific information.
+ */
+ switch (frametype) {
+
+ case X25_CALL_REQUEST:
+ dptr = skb_put(skb, 1);
+ *dptr++ = X25_CALL_REQUEST;
+ len = x25_addr_aton(addresses, &x25->dest_addr,
+ &x25->source_addr);
+ skb_put_data(skb, addresses, len);
+ len = x25_create_facilities(facilities,
+ &x25->facilities,
+ &x25->dte_facilities,
+ x25->neighbour->global_facil_mask);
+ skb_put_data(skb, facilities, len);
+ skb_put_data(skb, x25->calluserdata.cuddata,
+ x25->calluserdata.cudlength);
+ x25->calluserdata.cudlength = 0;
+ break;
+
+ case X25_CALL_ACCEPTED:
+ dptr = skb_put(skb, 2);
+ *dptr++ = X25_CALL_ACCEPTED;
+ *dptr++ = 0x00; /* Address lengths */
+ len = x25_create_facilities(facilities,
+ &x25->facilities,
+ &x25->dte_facilities,
+ x25->vc_facil_mask);
+ skb_put_data(skb, facilities, len);
+
+ /* fast select with no restriction on response
+ allows call user data. Userland must
+ ensure it is ours and not theirs */
+ if(x25->facilities.reverse & 0x80) {
+ skb_put_data(skb,
+ x25->calluserdata.cuddata,
+ x25->calluserdata.cudlength);
+ }
+ x25->calluserdata.cudlength = 0;
+ break;
+
+ case X25_CLEAR_REQUEST:
+ dptr = skb_put(skb, 3);
+ *dptr++ = frametype;
+ *dptr++ = x25->causediag.cause;
+ *dptr++ = x25->causediag.diagnostic;
+ break;
+
+ case X25_RESET_REQUEST:
+ dptr = skb_put(skb, 3);
+ *dptr++ = frametype;
+ *dptr++ = 0x00; /* XXX */
+ *dptr++ = 0x00; /* XXX */
+ break;
+
+ case X25_RR:
+ case X25_RNR:
+ case X25_REJ:
+ if (x25->neighbour->extended) {
+ dptr = skb_put(skb, 2);
+ *dptr++ = frametype;
+ *dptr++ = (x25->vr << 1) & 0xFE;
+ } else {
+ dptr = skb_put(skb, 1);
+ *dptr = frametype;
+ *dptr++ |= (x25->vr << 5) & 0xE0;
+ }
+ break;
+
+ case X25_CLEAR_CONFIRMATION:
+ case X25_INTERRUPT_CONFIRMATION:
+ case X25_RESET_CONFIRMATION:
+ dptr = skb_put(skb, 1);
+ *dptr = frametype;
+ break;
+ }
+
+ x25_transmit_link(skb, x25->neighbour);
+}
+
+/*
+ * Unpick the contents of the passed X.25 Packet Layer frame.
+ */
+int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q,
+ int *d, int *m)
+{
+ struct x25_sock *x25 = x25_sk(sk);
+ unsigned char *frame;
+
+ if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
+ return X25_ILLEGAL;
+ frame = skb->data;
+
+ *ns = *nr = *q = *d = *m = 0;
+
+ switch (frame[2]) {
+ case X25_CALL_REQUEST:
+ case X25_CALL_ACCEPTED:
+ case X25_CLEAR_REQUEST:
+ case X25_CLEAR_CONFIRMATION:
+ case X25_INTERRUPT:
+ case X25_INTERRUPT_CONFIRMATION:
+ case X25_RESET_REQUEST:
+ case X25_RESET_CONFIRMATION:
+ case X25_RESTART_REQUEST:
+ case X25_RESTART_CONFIRMATION:
+ case X25_REGISTRATION_REQUEST:
+ case X25_REGISTRATION_CONFIRMATION:
+ case X25_DIAGNOSTIC:
+ return frame[2];
+ }
+
+ if (x25->neighbour->extended) {
+ if (frame[2] == X25_RR ||
+ frame[2] == X25_RNR ||
+ frame[2] == X25_REJ) {
+ if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
+ return X25_ILLEGAL;
+ frame = skb->data;
+
+ *nr = (frame[3] >> 1) & 0x7F;
+ return frame[2];
+ }
+ } else {
+ if ((frame[2] & 0x1F) == X25_RR ||
+ (frame[2] & 0x1F) == X25_RNR ||
+ (frame[2] & 0x1F) == X25_REJ) {
+ *nr = (frame[2] >> 5) & 0x07;
+ return frame[2] & 0x1F;
+ }
+ }
+
+ if (x25->neighbour->extended) {
+ if ((frame[2] & 0x01) == X25_DATA) {
+ if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
+ return X25_ILLEGAL;
+ frame = skb->data;
+
+ *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
+ *d = (frame[0] & X25_D_BIT) == X25_D_BIT;
+ *m = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT;
+ *nr = (frame[3] >> 1) & 0x7F;
+ *ns = (frame[2] >> 1) & 0x7F;
+ return X25_DATA;
+ }
+ } else {
+ if ((frame[2] & 0x01) == X25_DATA) {
+ *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
+ *d = (frame[0] & X25_D_BIT) == X25_D_BIT;
+ *m = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT;
+ *nr = (frame[2] >> 5) & 0x07;
+ *ns = (frame[2] >> 1) & 0x07;
+ return X25_DATA;
+ }
+ }
+
+ pr_debug("invalid PLP frame %3ph\n", frame);
+
+ return X25_ILLEGAL;
+}
+
+void x25_disconnect(struct sock *sk, int reason, unsigned char cause,
+ unsigned char diagnostic)
+{
+ struct x25_sock *x25 = x25_sk(sk);
+
+ x25_clear_queues(sk);
+ x25_stop_timer(sk);
+
+ x25->lci = 0;
+ x25->state = X25_STATE_0;
+
+ x25->causediag.cause = cause;
+ x25->causediag.diagnostic = diagnostic;
+
+ sk->sk_state = TCP_CLOSE;
+ sk->sk_err = reason;
+ sk->sk_shutdown |= SEND_SHUTDOWN;
+
+ if (!sock_flag(sk, SOCK_DEAD)) {
+ sk->sk_state_change(sk);
+ sock_set_flag(sk, SOCK_DEAD);
+ }
+ if (x25->neighbour) {
+ read_lock_bh(&x25_list_lock);
+ x25_neigh_put(x25->neighbour);
+ x25->neighbour = NULL;
+ read_unlock_bh(&x25_list_lock);
+ }
+}
+
+/*
+ * Clear an own-rx-busy condition and tell the peer about this, provided
+ * that there is a significant amount of free receive buffer space available.
+ */
+void x25_check_rbuf(struct sock *sk)
+{
+ struct x25_sock *x25 = x25_sk(sk);
+
+ if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf >> 1) &&
+ (x25->condition & X25_COND_OWN_RX_BUSY)) {
+ x25->condition &= ~X25_COND_OWN_RX_BUSY;
+ x25->condition &= ~X25_COND_ACK_PENDING;
+ x25->vl = x25->vr;
+ x25_write_internal(sk, X25_RR);
+ x25_stop_timer(sk);
+ }
+}
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