/* * 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 * * This module: * This module is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * 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 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * This routine purges all of the queues of frames. */ void x25_clear_queues(struct sock *sk) { skb_queue_purge(&sk->write_queue); skb_queue_purge(&sk->protinfo.x25->ack_queue); skb_queue_purge(&sk->protinfo.x25->interrupt_in_queue); skb_queue_purge(&sk->protinfo.x25->interrupt_out_queue); skb_queue_purge(&sk->protinfo.x25->fragment_queue); } /* * This routine purges the input queue of those frames that have been * acknowledged. This replaces the boxes labelled "V(a) * SDL diagram. */ void x25_frames_acked(struct sock *sk, unsigned short nr) { struct sk_buff *skb; int modulus = sk->protinfo.x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS; /* * Remove all the ack-ed frames from the ack queue. */ if (sk->protinfo.x25->va != nr) while (skb_peek(&sk->protinfo.x25->ack_queue) != NULL && sk->protinfo.x25->va != nr) { skb = skb_dequeue(&sk->protinfo.x25->ack_queue); kfree_skb(skb); sk->protinfo.x25->va = (sk->protinfo.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(&sk->protinfo.x25->ack_queue)) != NULL) { if (skb_prev == NULL) skb_queue_head(&sk->write_queue, skb); else skb_append(skb_prev, skb); 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) { unsigned short vc = sk->protinfo.x25->va; int modulus = sk->protinfo.x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS; while (vc != sk->protinfo.x25->vs) { if (nr == vc) return 1; vc = (vc + 1) % modulus; } return nr == sk->protinfo.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 sk_buff *skb; unsigned char *dptr; unsigned char facilities[X25_MAX_FAC_LEN]; unsigned char addresses[1 + X25_ADDR_LEN]; unsigned char lci1, lci2; int len; /* * Default safe frame size. */ 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: len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_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: printk(KERN_ERR "X.25: 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 = (sk->protinfo.x25->lci >> 8) & 0x0F; lci2 = (sk->protinfo.x25->lci >> 0) & 0xFF; if (sk->protinfo.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, &sk->protinfo.x25->dest_addr, &sk->protinfo.x25->source_addr); dptr = skb_put(skb, len); memcpy(dptr, addresses, len); len = x25_create_facilities(facilities, &sk->protinfo.x25->facilities, sk->protinfo.x25->neighbour->global_facil_mask); dptr = skb_put(skb, len); memcpy(dptr, facilities, len); dptr = skb_put(skb, sk->protinfo.x25->calluserdata.cudlength); memcpy(dptr, sk->protinfo.x25->calluserdata.cuddata, sk->protinfo.x25->calluserdata.cudlength); sk->protinfo.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, &sk->protinfo.x25->facilities, sk->protinfo.x25->vc_facil_mask); dptr = skb_put(skb, len); memcpy(dptr, facilities, len); dptr = skb_put(skb, sk->protinfo.x25->calluserdata.cudlength); memcpy(dptr, sk->protinfo.x25->calluserdata.cuddata, sk->protinfo.x25->calluserdata.cudlength); sk->protinfo.x25->calluserdata.cudlength = 0; break; case X25_CLEAR_REQUEST: 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 (sk->protinfo.x25->neighbour->extended) { dptr = skb_put(skb, 2); *dptr++ = frametype; *dptr++ = (sk->protinfo.x25->vr } else { dptr = skb_put(skb, 1); *dptr = frametype; *dptr++ |= (sk->protinfo.x25->vr } 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, sk->protinfo.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) { unsigned char *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 (sk->protinfo.x25->neighbour->extended) { if (frame[2] == X25_RR || frame[2] == X25_RNR || frame[2] == X25_REJ) { *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 (sk->protinfo.x25->neighbour->extended) { 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[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; } } printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n", frame[0], frame[1], frame[2]); return X25_ILLEGAL; } void x25_disconnect(struct sock *sk, int reason, unsigned char cause, unsigned char diagnostic) { x25_clear_queues(sk); x25_stop_timer(sk); sk->protinfo.x25->lci = 0; sk->protinfo.x25->state = X25_STATE_0; sk->protinfo.x25->causediag.cause = cause; sk->protinfo.x25->causediag.diagnostic = diagnostic; sk->state = TCP_CLOSE; sk->err = reason; sk->shutdown |= SEND_SHUTDOWN; if (!sk->dead) sk->state_change(sk); sk->dead = 1; } /* * 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) { if (atomic_read(&sk->rmem_alloc) < (sk->rcvbuf / 2) && (sk->protinfo.x25->condition & X25_COND_OWN_RX_BUSY)) { sk->protinfo.x25->condition &= ~X25_COND_OWN_RX_BUSY; sk->protinfo.x25->condition &= ~X25_COND_ACK_PENDING; sk->protinfo.x25->vl = sk->protinfo.x25->vr; x25_write_internal(sk, X25_RR); x25_stop_timer(sk); } }
