diff options
Diffstat (limited to 'drivers/isdn/i4l/isdn_x25iface.c')
| -rw-r--r-- | drivers/isdn/i4l/isdn_x25iface.c | 332 |
1 files changed, 332 insertions, 0 deletions
diff --git a/drivers/isdn/i4l/isdn_x25iface.c b/drivers/isdn/i4l/isdn_x25iface.c new file mode 100644 index 000000000..e2d4e5823 --- /dev/null +++ b/drivers/isdn/i4l/isdn_x25iface.c @@ -0,0 +1,332 @@ +/* $Id: isdn_x25iface.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $ + * + * Linux ISDN subsystem, X.25 related functions + * + * This software may be used and distributed according to the terms + * of the GNU General Public License, incorporated herein by reference. + * + * stuff needed to support the Linux X.25 PLP code on top of devices that + * can provide a lab_b service using the concap_proto mechanism. + * This module supports a network interface which provides lapb_sematics + * -- as defined in Documentation/networking/x25-iface.txt -- to + * the upper layer and assumes that the lower layer provides a reliable + * data link service by means of the concap_device_ops callbacks. + * + * Only protocol specific stuff goes here. Device specific stuff + * goes to another -- device related -- concap_proto support source file. + * + */ + +/* #include <linux/isdn.h> */ +#include <linux/netdevice.h> +#include <linux/concap.h> +#include <linux/slab.h> +#include <linux/wanrouter.h> +#include <net/x25device.h> +#include "isdn_x25iface.h" + +/* for debugging messages not to cause an oops when device pointer is NULL*/ +#define MY_DEVNAME(dev) ((dev) ? (dev)->name : "DEVICE UNSPECIFIED") + + +typedef struct isdn_x25iface_proto_data { + int magic; + enum wan_states state; + /* Private stuff, not to be accessed via proto_data. We provide the + other storage for the concap_proto instance here as well, + enabling us to allocate both with just one kmalloc(): */ + struct concap_proto priv; +} ix25_pdata_t; + + + +/* is now in header file (extern): struct concap_proto * isdn_x25iface_proto_new(void); */ +static void isdn_x25iface_proto_del(struct concap_proto *); +static int isdn_x25iface_proto_close(struct concap_proto *); +static int isdn_x25iface_proto_restart(struct concap_proto *, + struct net_device *, + struct concap_device_ops *); +static int isdn_x25iface_xmit(struct concap_proto *, struct sk_buff *); +static int isdn_x25iface_receive(struct concap_proto *, struct sk_buff *); +static int isdn_x25iface_connect_ind(struct concap_proto *); +static int isdn_x25iface_disconn_ind(struct concap_proto *); + + +static struct concap_proto_ops ix25_pops = { + &isdn_x25iface_proto_new, + &isdn_x25iface_proto_del, + &isdn_x25iface_proto_restart, + &isdn_x25iface_proto_close, + &isdn_x25iface_xmit, + &isdn_x25iface_receive, + &isdn_x25iface_connect_ind, + &isdn_x25iface_disconn_ind +}; + +/* error message helper function */ +static void illegal_state_warn(unsigned state, unsigned char firstbyte) +{ + printk(KERN_WARNING "isdn_x25iface: firstbyte %x illegal in" + "current state %d\n", firstbyte, state); +} + +/* check protocol data field for consistency */ +static int pdata_is_bad(ix25_pdata_t *pda) { + + if (pda && pda->magic == ISDN_X25IFACE_MAGIC) return 0; + printk(KERN_WARNING + "isdn_x25iface_xxx: illegal pointer to proto data\n"); + return 1; +} + +/* create a new x25 interface protocol instance + */ +struct concap_proto *isdn_x25iface_proto_new(void) +{ + ix25_pdata_t *tmp = kmalloc(sizeof(ix25_pdata_t), GFP_KERNEL); + IX25DEBUG("isdn_x25iface_proto_new\n"); + if (tmp) { + tmp->magic = ISDN_X25IFACE_MAGIC; + tmp->state = WAN_UNCONFIGURED; + /* private data space used to hold the concap_proto data. + Only to be accessed via the returned pointer */ + spin_lock_init(&tmp->priv.lock); + tmp->priv.dops = NULL; + tmp->priv.net_dev = NULL; + tmp->priv.pops = &ix25_pops; + tmp->priv.flags = 0; + tmp->priv.proto_data = tmp; + return (&(tmp->priv)); + } + return NULL; +}; + +/* close the x25iface encapsulation protocol + */ +static int isdn_x25iface_proto_close(struct concap_proto *cprot) { + + ix25_pdata_t *tmp; + int ret = 0; + ulong flags; + + if (!cprot) { + printk(KERN_ERR "isdn_x25iface_proto_close: " + "invalid concap_proto pointer\n"); + return -1; + } + IX25DEBUG("isdn_x25iface_proto_close %s \n", MY_DEVNAME(cprot->net_dev)); + spin_lock_irqsave(&cprot->lock, flags); + cprot->dops = NULL; + cprot->net_dev = NULL; + tmp = cprot->proto_data; + if (pdata_is_bad(tmp)) { + ret = -1; + } else { + tmp->state = WAN_UNCONFIGURED; + } + spin_unlock_irqrestore(&cprot->lock, flags); + return ret; +} + +/* Delete the x25iface encapsulation protocol instance + */ +static void isdn_x25iface_proto_del(struct concap_proto *cprot) { + + ix25_pdata_t *tmp; + + IX25DEBUG("isdn_x25iface_proto_del \n"); + if (!cprot) { + printk(KERN_ERR "isdn_x25iface_proto_del: " + "concap_proto pointer is NULL\n"); + return; + } + tmp = cprot->proto_data; + if (tmp == NULL) { + printk(KERN_ERR "isdn_x25iface_proto_del: inconsistent " + "proto_data pointer (maybe already deleted?)\n"); + return; + } + /* close if the protocol is still open */ + if (cprot->dops) isdn_x25iface_proto_close(cprot); + /* freeing the storage should be sufficient now. But some additional + settings might help to catch wild pointer bugs */ + tmp->magic = 0; + cprot->proto_data = NULL; + + kfree(tmp); + return; +} + +/* (re-)initialize the data structures for x25iface encapsulation + */ +static int isdn_x25iface_proto_restart(struct concap_proto *cprot, + struct net_device *ndev, + struct concap_device_ops *dops) +{ + ix25_pdata_t *pda = cprot->proto_data; + ulong flags; + + IX25DEBUG("isdn_x25iface_proto_restart %s \n", MY_DEVNAME(ndev)); + + if (pdata_is_bad(pda)) return -1; + + if (!(dops && dops->data_req && dops->connect_req + && dops->disconn_req)) { + printk(KERN_WARNING "isdn_x25iface_restart: required dops" + " missing\n"); + isdn_x25iface_proto_close(cprot); + return -1; + } + spin_lock_irqsave(&cprot->lock, flags); + cprot->net_dev = ndev; + cprot->pops = &ix25_pops; + cprot->dops = dops; + pda->state = WAN_DISCONNECTED; + spin_unlock_irqrestore(&cprot->lock, flags); + return 0; +} + +/* deliver a dl_data frame received from i4l HL driver to the network layer + */ +static int isdn_x25iface_receive(struct concap_proto *cprot, struct sk_buff *skb) +{ + IX25DEBUG("isdn_x25iface_receive %s \n", MY_DEVNAME(cprot->net_dev)); + if (((ix25_pdata_t *)(cprot->proto_data)) + ->state == WAN_CONNECTED) { + if (skb_push(skb, 1)) { + skb->data[0] = X25_IFACE_DATA; + skb->protocol = x25_type_trans(skb, cprot->net_dev); + netif_rx(skb); + return 0; + } + } + printk(KERN_WARNING "isdn_x25iface_receive %s: not connected, skb dropped\n", MY_DEVNAME(cprot->net_dev)); + dev_kfree_skb(skb); + return -1; +} + +/* a connection set up is indicated by lower layer + */ +static int isdn_x25iface_connect_ind(struct concap_proto *cprot) +{ + struct sk_buff *skb; + enum wan_states *state_p + = &(((ix25_pdata_t *)(cprot->proto_data))->state); + IX25DEBUG("isdn_x25iface_connect_ind %s \n" + , MY_DEVNAME(cprot->net_dev)); + if (*state_p == WAN_UNCONFIGURED) { + printk(KERN_WARNING + "isdn_x25iface_connect_ind while unconfigured %s\n" + , MY_DEVNAME(cprot->net_dev)); + return -1; + } + *state_p = WAN_CONNECTED; + + skb = dev_alloc_skb(1); + if (skb) { + *(skb_put(skb, 1)) = X25_IFACE_CONNECT; + skb->protocol = x25_type_trans(skb, cprot->net_dev); + netif_rx(skb); + return 0; + } else { + printk(KERN_WARNING "isdn_x25iface_connect_ind: " + " out of memory -- disconnecting\n"); + cprot->dops->disconn_req(cprot); + return -1; + } +} + +/* a disconnect is indicated by lower layer + */ +static int isdn_x25iface_disconn_ind(struct concap_proto *cprot) +{ + struct sk_buff *skb; + enum wan_states *state_p + = &(((ix25_pdata_t *)(cprot->proto_data))->state); + IX25DEBUG("isdn_x25iface_disconn_ind %s \n", MY_DEVNAME(cprot->net_dev)); + if (*state_p == WAN_UNCONFIGURED) { + printk(KERN_WARNING + "isdn_x25iface_disconn_ind while unconfigured\n"); + return -1; + } + if (!cprot->net_dev) return -1; + *state_p = WAN_DISCONNECTED; + skb = dev_alloc_skb(1); + if (skb) { + *(skb_put(skb, 1)) = X25_IFACE_DISCONNECT; + skb->protocol = x25_type_trans(skb, cprot->net_dev); + netif_rx(skb); + return 0; + } else { + printk(KERN_WARNING "isdn_x25iface_disconn_ind:" + " out of memory\n"); + return -1; + } +} + +/* process a frame handed over to us from linux network layer. First byte + semantics as defined in Documentation/networking/x25-iface.txt +*/ +static int isdn_x25iface_xmit(struct concap_proto *cprot, struct sk_buff *skb) +{ + unsigned char firstbyte = skb->data[0]; + enum wan_states *state = &((ix25_pdata_t *)cprot->proto_data)->state; + int ret = 0; + IX25DEBUG("isdn_x25iface_xmit: %s first=%x state=%d\n", + MY_DEVNAME(cprot->net_dev), firstbyte, *state); + switch (firstbyte) { + case X25_IFACE_DATA: + if (*state == WAN_CONNECTED) { + skb_pull(skb, 1); + cprot->net_dev->trans_start = jiffies; + ret = (cprot->dops->data_req(cprot, skb)); + /* prepare for future retransmissions */ + if (ret) skb_push(skb, 1); + return ret; + } + illegal_state_warn(*state, firstbyte); + break; + case X25_IFACE_CONNECT: + if (*state == WAN_DISCONNECTED) { + *state = WAN_CONNECTING; + ret = cprot->dops->connect_req(cprot); + if (ret) { + /* reset state and notify upper layer about + * immidiatly failed attempts */ + isdn_x25iface_disconn_ind(cprot); + } + } else { + illegal_state_warn(*state, firstbyte); + } + break; + case X25_IFACE_DISCONNECT: + switch (*state) { + case WAN_DISCONNECTED: + /* Should not happen. However, give upper layer a + chance to recover from inconstistency but don't + trust the lower layer sending the disconn_confirm + when already disconnected */ + printk(KERN_WARNING "isdn_x25iface_xmit: disconnect " + " requested while disconnected\n"); + isdn_x25iface_disconn_ind(cprot); + break; /* prevent infinite loops */ + case WAN_CONNECTING: + case WAN_CONNECTED: + *state = WAN_DISCONNECTED; + cprot->dops->disconn_req(cprot); + break; + default: + illegal_state_warn(*state, firstbyte); + } + break; + case X25_IFACE_PARAMS: + printk(KERN_WARNING "isdn_x25iface_xmit: setting of lapb" + " options not yet supported\n"); + break; + default: + printk(KERN_WARNING "isdn_x25iface_xmit: frame with illegal" + " first byte %x ignored:\n", firstbyte); + } + dev_kfree_skb(skb); + return 0; +} |