cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

x25_dev.c (4100B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 *	X.25 Packet Layer release 002
      4 *
      5 *	This is ALPHA test software. This code may break your machine, randomly fail to work with new
      6 *	releases, misbehave and/or generally screw up. It might even work.
      7 *
      8 *	This code REQUIRES 2.1.15 or higher
      9 *
     10 *	History
     11 *	X.25 001	Jonathan Naylor	Started coding.
     12 *      2000-09-04	Henner Eisen	Prevent freeing a dangling skb.
     13 */
     14
     15#define pr_fmt(fmt) "X25: " fmt
     16
     17#include <linux/kernel.h>
     18#include <linux/netdevice.h>
     19#include <linux/skbuff.h>
     20#include <linux/slab.h>
     21#include <net/sock.h>
     22#include <linux/if_arp.h>
     23#include <net/x25.h>
     24#include <net/x25device.h>
     25
     26static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *nb)
     27{
     28	struct sock *sk;
     29	unsigned short frametype;
     30	unsigned int lci;
     31
     32	if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
     33		return 0;
     34
     35	frametype = skb->data[2];
     36	lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
     37
     38	/*
     39	 *	LCI of zero is always for us, and its always a link control
     40	 *	frame.
     41	 */
     42	if (lci == 0) {
     43		x25_link_control(skb, nb, frametype);
     44		return 0;
     45	}
     46
     47	/*
     48	 *	Find an existing socket.
     49	 */
     50	if ((sk = x25_find_socket(lci, nb)) != NULL) {
     51		int queued = 1;
     52
     53		skb_reset_transport_header(skb);
     54		bh_lock_sock(sk);
     55		if (!sock_owned_by_user(sk)) {
     56			queued = x25_process_rx_frame(sk, skb);
     57		} else {
     58			queued = !sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf));
     59		}
     60		bh_unlock_sock(sk);
     61		sock_put(sk);
     62		return queued;
     63	}
     64
     65	/*
     66	 *	Is is a Call Request ? if so process it.
     67	 */
     68	if (frametype == X25_CALL_REQUEST)
     69		return x25_rx_call_request(skb, nb, lci);
     70
     71	/*
     72	 * 	Its not a Call Request, nor is it a control frame.
     73	 *	Can we forward it?
     74	 */
     75
     76	if (x25_forward_data(lci, nb, skb)) {
     77		if (frametype == X25_CLEAR_CONFIRMATION) {
     78			x25_clear_forward_by_lci(lci);
     79		}
     80		kfree_skb(skb);
     81		return 1;
     82	}
     83
     84/*
     85	x25_transmit_clear_request(nb, lci, 0x0D);
     86*/
     87
     88	if (frametype != X25_CLEAR_CONFIRMATION)
     89		pr_debug("x25_receive_data(): unknown frame type %2x\n",frametype);
     90
     91	return 0;
     92}
     93
     94int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev,
     95			   struct packet_type *ptype, struct net_device *orig_dev)
     96{
     97	struct sk_buff *nskb;
     98	struct x25_neigh *nb;
     99
    100	if (!net_eq(dev_net(dev), &init_net))
    101		goto drop;
    102
    103	nskb = skb_copy(skb, GFP_ATOMIC);
    104	if (!nskb)
    105		goto drop;
    106	kfree_skb(skb);
    107	skb = nskb;
    108
    109	/*
    110	 * Packet received from unrecognised device, throw it away.
    111	 */
    112	nb = x25_get_neigh(dev);
    113	if (!nb) {
    114		pr_debug("unknown neighbour - %s\n", dev->name);
    115		goto drop;
    116	}
    117
    118	if (!pskb_may_pull(skb, 1)) {
    119		x25_neigh_put(nb);
    120		return 0;
    121	}
    122
    123	switch (skb->data[0]) {
    124
    125	case X25_IFACE_DATA:
    126		skb_pull(skb, 1);
    127		if (x25_receive_data(skb, nb)) {
    128			x25_neigh_put(nb);
    129			goto out;
    130		}
    131		break;
    132
    133	case X25_IFACE_CONNECT:
    134		x25_link_established(nb);
    135		break;
    136
    137	case X25_IFACE_DISCONNECT:
    138		x25_link_terminated(nb);
    139		break;
    140	}
    141	x25_neigh_put(nb);
    142drop:
    143	kfree_skb(skb);
    144out:
    145	return 0;
    146}
    147
    148void x25_establish_link(struct x25_neigh *nb)
    149{
    150	struct sk_buff *skb;
    151	unsigned char *ptr;
    152
    153	switch (nb->dev->type) {
    154	case ARPHRD_X25:
    155		if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {
    156			pr_err("x25_dev: out of memory\n");
    157			return;
    158		}
    159		ptr  = skb_put(skb, 1);
    160		*ptr = X25_IFACE_CONNECT;
    161		break;
    162
    163	default:
    164		return;
    165	}
    166
    167	skb->protocol = htons(ETH_P_X25);
    168	skb->dev      = nb->dev;
    169
    170	dev_queue_xmit(skb);
    171}
    172
    173void x25_terminate_link(struct x25_neigh *nb)
    174{
    175	struct sk_buff *skb;
    176	unsigned char *ptr;
    177
    178	if (nb->dev->type != ARPHRD_X25)
    179		return;
    180
    181	skb = alloc_skb(1, GFP_ATOMIC);
    182	if (!skb) {
    183		pr_err("x25_dev: out of memory\n");
    184		return;
    185	}
    186
    187	ptr  = skb_put(skb, 1);
    188	*ptr = X25_IFACE_DISCONNECT;
    189
    190	skb->protocol = htons(ETH_P_X25);
    191	skb->dev      = nb->dev;
    192	dev_queue_xmit(skb);
    193}
    194
    195void x25_send_frame(struct sk_buff *skb, struct x25_neigh *nb)
    196{
    197	unsigned char *dptr;
    198
    199	skb_reset_network_header(skb);
    200
    201	switch (nb->dev->type) {
    202	case ARPHRD_X25:
    203		dptr  = skb_push(skb, 1);
    204		*dptr = X25_IFACE_DATA;
    205		break;
    206
    207	default:
    208		kfree_skb(skb);
    209		return;
    210	}
    211
    212	skb->protocol = htons(ETH_P_X25);
    213	skb->dev      = nb->dev;
    214
    215	dev_queue_xmit(skb);
    216}