// 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 New timer architecture. * mar/20/00 Daniela Squassoni Disabling/enabling of facilities * negotiation. * 2000-09-04 Henner Eisen dev_hold() / dev_put() for x25_neigh. */ #define pr_fmt(fmt) "X25: " fmt #include <linux/kernel.h> #include <linux/jiffies.h> #include <linux/timer.h> #include <linux/slab.h> #include <linux/netdevice.h> #include <linux/skbuff.h> #include <linux/uaccess.h> #include <linux/init.h> #include <net/x25.h> LIST_HEAD(x25_neigh_list); DEFINE_RWLOCK(x25_neigh_list_lock); static void x25_t20timer_expiry(struct timer_list *); static void x25_transmit_restart_confirmation(struct x25_neigh *nb); static void x25_transmit_restart_request(struct x25_neigh *nb); /* * Linux set/reset timer routines */ static inline void x25_start_t20timer(struct x25_neigh *nb) { mod_timer(&nb->t20timer, jiffies + nb->t20); } static void x25_t20timer_expiry(struct timer_list *t) { struct x25_neigh *nb = from_timer(nb, t, t20timer); x25_transmit_restart_request(nb); x25_start_t20timer(nb); } static inline void x25_stop_t20timer(struct x25_neigh *nb) { del_timer(&nb->t20timer); } static inline int x25_t20timer_pending(struct x25_neigh *nb) { return timer_pending(&nb->t20timer); } /* * This handles all restart and diagnostic frames. */ void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb, unsigned short frametype) { struct sk_buff *skbn; int confirm; switch (frametype) { case X25_RESTART_REQUEST: confirm = !x25_t20timer_pending(nb); x25_stop_t20timer(nb); nb->state = X25_LINK_STATE_3; if (confirm) x25_transmit_restart_confirmation(nb); break; case X25_RESTART_CONFIRMATION: x25_stop_t20timer(nb); nb->state = X25_LINK_STATE_3; break; case X25_DIAGNOSTIC: if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 4)) break; pr_warn("diagnostic #%d - %02X %02X %02X\n", skb->data[3], skb->data[4], skb->data[5], skb->data[6]); break; default: pr_warn("received unknown %02X with LCI 000\n", frametype); break; } if (nb->state == X25_LINK_STATE_3) while ((skbn = skb_dequeue(&nb->queue)) != NULL) x25_send_frame(skbn, nb); } /* * This routine is called when a Restart Request is needed */ static void x25_transmit_restart_request(struct x25_neigh *nb) { unsigned char *dptr; int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2; struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC); if (!skb) return; skb_reserve(skb, X25_MAX_L2_LEN); dptr = skb_put(skb, X25_STD_MIN_LEN + 2); *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ; *dptr++ = 0x00; *dptr++ = X25_RESTART_REQUEST; *dptr++ = 0x00; *dptr++ = 0; skb->sk = NULL; x25_send_frame(skb, nb); } /* * This routine is called when a Restart Confirmation is needed */ static void x25_transmit_restart_confirmation(struct x25_neigh *nb) { unsigned char *dptr; int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN; struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC); if (!skb) return; skb_reserve(skb, X25_MAX_L2_LEN); dptr = skb_put(skb, X25_STD_MIN_LEN); *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ; *dptr++ = 0x00; *dptr++ = X25_RESTART_CONFIRMATION; skb->sk = NULL; x25_send_frame(skb, nb); } /* * This routine is called when a Clear Request is needed outside of the context * of a connected socket. */ void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci, unsigned char cause) { unsigned char *dptr; int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2; struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC); if (!skb) return; skb_reserve(skb, X25_MAX_L2_LEN); dptr = skb_put(skb, X25_STD_MIN_LEN + 2); *dptr++ = ((lci >> 8) & 0x0F) | (nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ); *dptr++ = (lci >> 0) & 0xFF; *dptr++ = X25_CLEAR_REQUEST; *dptr++ = cause; *dptr++ = 0x00; skb->sk = NULL; x25_send_frame(skb, nb); } void x25_transmit_link(struct sk_buff *skb, struct x25_neigh *nb) { switch (nb->state) { case X25_LINK_STATE_0: skb_queue_tail(&nb->queue, skb); nb->state = X25_LINK_STATE_1; x25_establish_link(nb); break; case X25_LINK_STATE_1: case X25_LINK_STATE_2: skb_queue_tail(&nb->queue, skb); break; case X25_LINK_STATE_3: x25_send_frame(skb, nb); break; } } /* * Called when the link layer has become established. */ void x25_link_established(struct x25_neigh *nb) { switch (nb->state) { case X25_LINK_STATE_0: nb->state = X25_LINK_STATE_2; break; case X25_LINK_STATE_1: x25_transmit_restart_request(nb); nb->state = X25_LINK_STATE_2; x25_start_t20timer(nb); break; } } /* * Called when the link layer has terminated, or an establishment * request has failed. */ void x25_link_terminated(struct x25_neigh *nb) { nb->state = X25_LINK_STATE_0; /* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */ x25_kill_by_neigh(nb); } /* * Add a new device. */ void x25_link_device_up(struct net_device *dev) { struct x25_neigh *nb = kmalloc(sizeof(*nb), GFP_ATOMIC); if (!nb) return; skb_queue_head_init(&nb->queue); timer_setup(&nb->t20timer, x25_t20timer_expiry, 0); dev_hold(dev); nb->dev = dev; nb->state = X25_LINK_STATE_0; nb->extended = 0; /* * Enables negotiation */ nb->global_facil_mask = X25_MASK_REVERSE | X25_MASK_THROUGHPUT | X25_MASK_PACKET_SIZE | X25_MASK_WINDOW_SIZE; nb->t20 = sysctl_x25_restart_request_timeout; refcount_set(&nb->refcnt, 1); write_lock_bh(&x25_neigh_list_lock); list_add(&nb->node, &x25_neigh_list); write_unlock_bh(&x25_neigh_list_lock); } /** * __x25_remove_neigh - remove neighbour from x25_neigh_list * @nb: - neigh to remove * * Remove neighbour from x25_neigh_list. If it was there. * Caller must hold x25_neigh_list_lock. */ static void __x25_remove_neigh(struct x25_neigh *nb) { skb_queue_purge(&nb->queue); x25_stop_t20timer(nb); if (nb->node.next) { list_del(&nb->node); x25_neigh_put(nb); } } /* * A device has been removed, remove its links. */ void x25_link_device_down(struct net_device *dev) { struct x25_neigh *nb; struct list_head *entry, *tmp; write_lock_bh(&x25_neigh_list_lock); list_for_each_safe(entry, tmp, &x25_neigh_list) { nb = list_entry(entry, struct x25_neigh, node); if (nb->dev == dev) { __x25_remove_neigh(nb); dev_put(dev); } } write_unlock_bh(&x25_neigh_list_lock); } /* * Given a device, return the neighbour address. */ struct x25_neigh *x25_get_neigh(struct net_device *dev) { struct x25_neigh *nb, *use = NULL; struct list_head *entry; read_lock_bh(&x25_neigh_list_lock); list_for_each(entry, &x25_neigh_list) { nb = list_entry(entry, struct x25_neigh, node); if (nb->dev == dev) { use = nb; break; } } if (use) x25_neigh_hold(use); read_unlock_bh(&x25_neigh_list_lock); return use; } /* * Handle the ioctls that control the subscription functions. */ int x25_subscr_ioctl(unsigned int cmd, void __user *arg) { struct x25_subscrip_struct x25_subscr; struct x25_neigh *nb; struct net_device *dev; int rc = -EINVAL; if (cmd != SIOCX25GSUBSCRIP && cmd != SIOCX25SSUBSCRIP) goto out; rc = -EFAULT; if (copy_from_user(&x25_subscr, arg, sizeof(x25_subscr))) goto out; rc = -EINVAL; if ((dev = x25_dev_get(x25_subscr.device)) == NULL) goto out; if ((nb = x25_get_neigh(dev)) == NULL) goto out_dev_put; dev_put(dev); if (cmd == SIOCX25GSUBSCRIP) { read_lock_bh(&x25_neigh_list_lock); x25_subscr.extended = nb->extended; x25_subscr.global_facil_mask = nb->global_facil_mask; read_unlock_bh(&x25_neigh_list_lock); rc = copy_to_user(arg, &x25_subscr, sizeof(x25_subscr)) ? -EFAULT : 0; } else { rc = -EINVAL; if (!(x25_subscr.extended && x25_subscr.extended != 1)) { rc = 0; write_lock_bh(&x25_neigh_list_lock); nb->extended = x25_subscr.extended; nb->global_facil_mask = x25_subscr.global_facil_mask; write_unlock_bh(&x25_neigh_list_lock); } } x25_neigh_put(nb); out: return rc; out_dev_put: dev_put(dev); goto out; } /* * Release all memory associated with X.25 neighbour structures. */ void __exit x25_link_free(void) { struct x25_neigh *nb; struct list_head *entry, *tmp; write_lock_bh(&x25_neigh_list_lock); list_for_each_safe(entry, tmp, &x25_neigh_list) { struct net_device *dev; nb = list_entry(entry, struct x25_neigh, node); dev = nb->dev; __x25_remove_neigh(nb); dev_put(dev); } write_unlock_bh(&x25_neigh_list_lock); }