diff options
Diffstat (limited to 'net/x25/x25_dev.c')
| -rw-r--r-- | net/x25/x25_dev.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/net/x25/x25_dev.c b/net/x25/x25_dev.c new file mode 100644 index 000000000..748d8630a --- /dev/null +++ b/net/x25/x25_dev.c @@ -0,0 +1,216 @@ +// 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. + * 2000-09-04 Henner Eisen Prevent freeing a dangling skb. + */ + +#define pr_fmt(fmt) "X25: " fmt + +#include <linux/kernel.h> +#include <linux/netdevice.h> +#include <linux/skbuff.h> +#include <linux/slab.h> +#include <net/sock.h> +#include <linux/if_arp.h> +#include <net/x25.h> +#include <net/x25device.h> + +static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *nb) +{ + struct sock *sk; + unsigned short frametype; + unsigned int lci; + + if (!pskb_may_pull(skb, X25_STD_MIN_LEN)) + return 0; + + frametype = skb->data[2]; + lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF); + + /* + * 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_reset_transport_header(skb); + bh_lock_sock(sk); + if (!sock_owned_by_user(sk)) { + queued = x25_process_rx_frame(sk, skb); + } else { + queued = !sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)); + } + bh_unlock_sock(sk); + sock_put(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. + * Can we forward it? + */ + + if (x25_forward_data(lci, nb, skb)) { + if (frametype == X25_CLEAR_CONFIRMATION) { + x25_clear_forward_by_lci(lci); + } + kfree_skb(skb); + return 1; + } + +/* + x25_transmit_clear_request(nb, lci, 0x0D); +*/ + + if (frametype != X25_CLEAR_CONFIRMATION) + pr_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; + + if (!net_eq(dev_net(dev), &init_net)) + goto drop; + + 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) { + pr_debug("unknown neighbour - %s\n", dev->name); + goto drop; + } + + if (!pskb_may_pull(skb, 1)) { + x25_neigh_put(nb); + goto drop; + } + + switch (skb->data[0]) { + + case X25_IFACE_DATA: + skb_pull(skb, 1); + if (x25_receive_data(skb, nb)) { + x25_neigh_put(nb); + goto out; + } + break; + + case X25_IFACE_CONNECT: + x25_link_established(nb); + break; + + case X25_IFACE_DISCONNECT: + 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) { + pr_err("x25_dev: out of memory\n"); + return; + } + ptr = skb_put(skb, 1); + *ptr = X25_IFACE_CONNECT; + break; + + 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 (nb->dev->type != ARPHRD_X25) + return; + + skb = alloc_skb(1, GFP_ATOMIC); + if (!skb) { + pr_err("x25_dev: out of memory\n"); + return; + } + + ptr = skb_put(skb, 1); + *ptr = X25_IFACE_DISCONNECT; + + 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_reset_network_header(skb); + + switch (nb->dev->type) { + case ARPHRD_X25: + dptr = skb_push(skb, 1); + *dptr = X25_IFACE_DATA; + break; + + default: + kfree_skb(skb); + return; + } + + skb->protocol = htons(ETH_P_X25); + skb->dev = nb->dev; + + dev_queue_xmit(skb); +} |