diff options
Diffstat (limited to 'net/phonet/pep-gprs.c')
| -rw-r--r-- | net/phonet/pep-gprs.c | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/net/phonet/pep-gprs.c b/net/phonet/pep-gprs.c new file mode 100644 index 000000000..fa8237fdc --- /dev/null +++ b/net/phonet/pep-gprs.c @@ -0,0 +1,327 @@ +/* + * File: pep-gprs.c + * + * GPRS over Phonet pipe end point socket + * + * Copyright (C) 2008 Nokia Corporation. + * + * Author: Rémi Denis-Courmont + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA + * 02110-1301 USA + */ + +#include <linux/kernel.h> +#include <linux/netdevice.h> +#include <linux/if_ether.h> +#include <linux/if_arp.h> +#include <net/sock.h> + +#include <linux/if_phonet.h> +#include <net/tcp_states.h> +#include <net/phonet/gprs.h> + +#define GPRS_DEFAULT_MTU 1400 + +struct gprs_dev { + struct sock *sk; + void (*old_state_change)(struct sock *); + void (*old_data_ready)(struct sock *); + void (*old_write_space)(struct sock *); + + struct net_device *dev; +}; + +static __be16 gprs_type_trans(struct sk_buff *skb) +{ + const u8 *pvfc; + u8 buf; + + pvfc = skb_header_pointer(skb, 0, 1, &buf); + if (!pvfc) + return htons(0); + /* Look at IP version field */ + switch (*pvfc >> 4) { + case 4: + return htons(ETH_P_IP); + case 6: + return htons(ETH_P_IPV6); + } + return htons(0); +} + +static void gprs_writeable(struct gprs_dev *gp) +{ + struct net_device *dev = gp->dev; + + if (pep_writeable(gp->sk)) + netif_wake_queue(dev); +} + +/* + * Socket callbacks + */ + +static void gprs_state_change(struct sock *sk) +{ + struct gprs_dev *gp = sk->sk_user_data; + + if (sk->sk_state == TCP_CLOSE_WAIT) { + struct net_device *dev = gp->dev; + + netif_stop_queue(dev); + netif_carrier_off(dev); + } +} + +static int gprs_recv(struct gprs_dev *gp, struct sk_buff *skb) +{ + struct net_device *dev = gp->dev; + int err = 0; + __be16 protocol = gprs_type_trans(skb); + + if (!protocol) { + err = -EINVAL; + goto drop; + } + + if (skb_headroom(skb) & 3) { + struct sk_buff *rskb, *fs; + int flen = 0; + + /* Phonet Pipe data header may be misaligned (3 bytes), + * so wrap the IP packet as a single fragment of an head-less + * socket buffer. The network stack will pull what it needs, + * but at least, the whole IP payload is not memcpy'd. */ + rskb = netdev_alloc_skb(dev, 0); + if (!rskb) { + err = -ENOBUFS; + goto drop; + } + skb_shinfo(rskb)->frag_list = skb; + rskb->len += skb->len; + rskb->data_len += rskb->len; + rskb->truesize += rskb->len; + + /* Avoid nested fragments */ + skb_walk_frags(skb, fs) + flen += fs->len; + skb->next = skb_shinfo(skb)->frag_list; + skb_frag_list_init(skb); + skb->len -= flen; + skb->data_len -= flen; + skb->truesize -= flen; + + skb = rskb; + } + + skb->protocol = protocol; + skb_reset_mac_header(skb); + skb->dev = dev; + + if (likely(dev->flags & IFF_UP)) { + dev->stats.rx_packets++; + dev->stats.rx_bytes += skb->len; + netif_rx(skb); + skb = NULL; + } else + err = -ENODEV; + +drop: + if (skb) { + dev_kfree_skb(skb); + dev->stats.rx_dropped++; + } + return err; +} + +static void gprs_data_ready(struct sock *sk) +{ + struct gprs_dev *gp = sk->sk_user_data; + struct sk_buff *skb; + + while ((skb = pep_read(sk)) != NULL) { + skb_orphan(skb); + gprs_recv(gp, skb); + } +} + +static void gprs_write_space(struct sock *sk) +{ + struct gprs_dev *gp = sk->sk_user_data; + + if (netif_running(gp->dev)) + gprs_writeable(gp); +} + +/* + * Network device callbacks + */ + +static int gprs_open(struct net_device *dev) +{ + struct gprs_dev *gp = netdev_priv(dev); + + gprs_writeable(gp); + return 0; +} + +static int gprs_close(struct net_device *dev) +{ + netif_stop_queue(dev); + return 0; +} + +static netdev_tx_t gprs_xmit(struct sk_buff *skb, struct net_device *dev) +{ + struct gprs_dev *gp = netdev_priv(dev); + struct sock *sk = gp->sk; + int len, err; + + switch (skb->protocol) { + case htons(ETH_P_IP): + case htons(ETH_P_IPV6): + break; + default: + dev_kfree_skb(skb); + return NETDEV_TX_OK; + } + + skb_orphan(skb); + skb_set_owner_w(skb, sk); + len = skb->len; + err = pep_write(sk, skb); + if (err) { + net_dbg_ratelimited("%s: TX error (%d)\n", dev->name, err); + dev->stats.tx_aborted_errors++; + dev->stats.tx_errors++; + } else { + dev->stats.tx_packets++; + dev->stats.tx_bytes += len; + } + + netif_stop_queue(dev); + if (pep_writeable(sk)) + netif_wake_queue(dev); + return NETDEV_TX_OK; +} + +static int gprs_set_mtu(struct net_device *dev, int new_mtu) +{ + if ((new_mtu < 576) || (new_mtu > (PHONET_MAX_MTU - 11))) + return -EINVAL; + + dev->mtu = new_mtu; + return 0; +} + +static const struct net_device_ops gprs_netdev_ops = { + .ndo_open = gprs_open, + .ndo_stop = gprs_close, + .ndo_start_xmit = gprs_xmit, + .ndo_change_mtu = gprs_set_mtu, +}; + +static void gprs_setup(struct net_device *dev) +{ + dev->features = NETIF_F_FRAGLIST; + dev->type = ARPHRD_PHONET_PIPE; + dev->flags = IFF_POINTOPOINT | IFF_NOARP; + dev->mtu = GPRS_DEFAULT_MTU; + dev->hard_header_len = 0; + dev->addr_len = 0; + dev->tx_queue_len = 10; + + dev->netdev_ops = &gprs_netdev_ops; + dev->destructor = free_netdev; +} + +/* + * External interface + */ + +/* + * Attach a GPRS interface to a datagram socket. + * Returns the interface index on success, negative error code on error. + */ +int gprs_attach(struct sock *sk) +{ + static const char ifname[] = "gprs%d"; + struct gprs_dev *gp; + struct net_device *dev; + int err; + + if (unlikely(sk->sk_type == SOCK_STREAM)) + return -EINVAL; /* need packet boundaries */ + + /* Create net device */ + dev = alloc_netdev(sizeof(*gp), ifname, NET_NAME_UNKNOWN, gprs_setup); + if (!dev) + return -ENOMEM; + gp = netdev_priv(dev); + gp->sk = sk; + gp->dev = dev; + + netif_stop_queue(dev); + err = register_netdev(dev); + if (err) { + free_netdev(dev); + return err; + } + + lock_sock(sk); + if (unlikely(sk->sk_user_data)) { + err = -EBUSY; + goto out_rel; + } + if (unlikely((1 << sk->sk_state & (TCPF_CLOSE|TCPF_LISTEN)) || + sock_flag(sk, SOCK_DEAD))) { + err = -EINVAL; + goto out_rel; + } + sk->sk_user_data = gp; + gp->old_state_change = sk->sk_state_change; + gp->old_data_ready = sk->sk_data_ready; + gp->old_write_space = sk->sk_write_space; + sk->sk_state_change = gprs_state_change; + sk->sk_data_ready = gprs_data_ready; + sk->sk_write_space = gprs_write_space; + release_sock(sk); + sock_hold(sk); + + printk(KERN_DEBUG"%s: attached\n", dev->name); + return dev->ifindex; + +out_rel: + release_sock(sk); + unregister_netdev(dev); + return err; +} + +void gprs_detach(struct sock *sk) +{ + struct gprs_dev *gp = sk->sk_user_data; + struct net_device *dev = gp->dev; + + lock_sock(sk); + sk->sk_user_data = NULL; + sk->sk_state_change = gp->old_state_change; + sk->sk_data_ready = gp->old_data_ready; + sk->sk_write_space = gp->old_write_space; + release_sock(sk); + + printk(KERN_DEBUG"%s: detached\n", dev->name); + unregister_netdev(dev); + sock_put(sk); +} |