/* * 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. * 2000-09-04 Henner Eisen Prevent freeing a dangling skb. */ #include #include #include #include #include #include static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *nb) { struct sock *sk; unsigned short frametype; unsigned int lci; frametype = skb->data[2]; lci = ((skb->data[0] data[1] /* * LCI of zero is always for us, and its always a link control * frame. */ if (lci == 0) { x25_link_control(skb, nb, frametype); return 0; } /* * Find an existing socket. */ if ((sk = x25_find_socket(lci, nb)) != NULL) { int queued = 1; skb->h.raw = skb->data; bh_lock_sock(sk); if (!sock_owned_by_user(sk)) { queued = x25_process_rx_frame(sk, skb); } else { sk_add_backlog(sk, skb); } bh_unlock_sock(sk); return queued; } /* * Is is a Call Request ? if so process it. */ if (frametype == X25_CALL_REQUEST) return x25_rx_call_request(skb, nb, lci); /* * Its not a Call Request, nor is it a control frame. * Let caller throw it away. */ /* x25_transmit_clear_request(nb, lci, 0x0D); */ if (frametype != X25_CLEAR_CONFIRMATION) printk(KERN_DEBUG "x25_receive_data(): unknown frame type %2x\n",frametype); return 0; } int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev) { struct sk_buff *nskb; struct x25_neigh *nb; nskb = skb_copy(skb, GFP_ATOMIC); if (!nskb) goto drop; kfree_skb(skb); skb = nskb; /* * Packet received from unrecognised device, throw it away. */ nb = x25_get_neigh(dev); if (!nb) { printk(KERN_DEBUG "X.25: unknown neighbour - %s\n", dev->name); goto drop; } switch (skb->data[0]) { case 0x00: skb_pull(skb, 1); if (x25_receive_data(skb, nb)) { x25_neigh_put(nb); goto out; } break; case 0x01: x25_link_established(nb); break; case 0x02: x25_link_terminated(nb); break; } x25_neigh_put(nb); drop: kfree_skb(skb); out: return 0; } void x25_establish_link(struct x25_neigh *nb) { struct sk_buff *skb; unsigned char *ptr; switch (nb->dev->type) { case ARPHRD_X25: if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) { printk(KERN_ERR "x25_dev: out of memory\n"); return; } ptr = skb_put(skb, 1); *ptr = 0x01; break; #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE) case ARPHRD_ETHER: return; #endif default: return; } skb->protocol = htons(ETH_P_X25); skb->dev = nb->dev; dev_queue_xmit(skb); } void x25_terminate_link(struct x25_neigh *nb) { struct sk_buff *skb; unsigned char *ptr; #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE) if (nb->dev->type == ARPHRD_ETHER) return; #endif if (nb->dev->type != ARPHRD_X25) return; skb = alloc_skb(1, GFP_ATOMIC); if (!skb) { printk(KERN_ERR "x25_dev: out of memory\n"); return; } ptr = skb_put(skb, 1); *ptr = 0x02; skb->protocol = htons(ETH_P_X25); skb->dev = nb->dev; dev_queue_xmit(skb); } void x25_send_frame(struct sk_buff *skb, struct x25_neigh *nb) { unsigned char *dptr; skb->nh.raw = skb->data; switch (nb->dev->type) { case ARPHRD_X25: dptr = skb_push(skb, 1); *dptr = 0x00; break; #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE) case ARPHRD_ETHER: kfree_skb(skb); return; #endif default: kfree_skb(skb); return; } skb->protocol = htons(ETH_P_X25); skb->dev = nb->dev; dev_queue_xmit(skb); }
