/* * TUN - Universal TUN/TAP device driver. * Copyright (C) 1999-2002 Maxim Krasnyansky * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * 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. * * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $ */ /* * Daniel Podlejski * Modifications for 2.3.99-pre5 kernel. */ #define TUN_VER "1.5" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef TUN_DEBUG static int debug; #endif /* Network device part of the driver */ /* Net device open. */ static int tun_net_open(struct net_device *dev) { netif_start_queue(dev); return 0; } /* Net device close. */ static int tun_net_close(struct net_device *dev) { netif_stop_queue(dev); return 0; } /* Net device start xmit */ static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev) { struct tun_struct *tun = (struct tun_struct *)dev->priv; DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->name, skb->len); /* Drop packet if interface is not attached */ if (!tun->attached) goto drop; /* Queue packet */ if (!(tun->flags & TUN_ONE_QUEUE)) { /* Normal queueing mode. * Packet scheduler handles dropping. */ if (skb_queue_len(&tun->readq) >= TUN_READQ_SIZE) netif_stop_queue(dev); } else { /* Single queue mode. * Driver handles dropping itself. */ if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) goto drop; } skb_queue_tail(&tun->readq, skb); /* Notify and wake up reader process */ if (tun->flags & TUN_FASYNC) kill_fasync(&tun->fasync, SIGIO, POLL_IN); wake_up_interruptible(&tun->read_wait); return 0; drop: tun->stats.tx_dropped++; kfree_skb(skb); return 0; } static void tun_net_mclist(struct net_device *dev) { /* Nothing to do for multicast filters. * We always accept all frames. */ return; } static struct net_device_stats *tun_net_stats(struct net_device *dev) { struct tun_struct *tun = (struct tun_struct *)dev->priv; return &tun->stats; } /* Initialize net device. */ int tun_net_init(struct net_device *dev) { struct tun_struct *tun = (struct tun_struct *)dev->priv; DBG(KERN_INFO "%s: tun_net_init\n", tun->name); SET_MODULE_OWNER(dev); dev->open = tun_net_open; dev->hard_start_xmit = tun_net_xmit; dev->stop = tun_net_close; dev->get_stats = tun_net_stats; switch (tun->flags & TUN_TYPE_MASK) { case TUN_TUN_DEV: /* Point-to-Point TUN Device */ dev->hard_header_len = 0; dev->addr_len = 0; dev->mtu = 1500; /* Zero header length */ dev->type = ARPHRD_NONE; dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; dev->tx_queue_len = 10; break; case TUN_TAP_DEV: /* Ethernet TAP Device */ dev->set_multicast_list = tun_net_mclist; /* Generate random Ethernet address. */ *(u16 *)dev->dev_addr = htons(0x00FF); get_random_bytes(dev->dev_addr + sizeof(u16), 4); ether_setup(dev); break; }; return 0; } /* Character device part */ /* Poll */ static unsigned int tun_chr_poll(struct file *file, poll_table * wait) { struct tun_struct *tun = (struct tun_struct *)file->private_data; unsigned int mask = POLLOUT | POLLWRNORM; if (!tun) return -EBADFD; DBG(KERN_INFO "%s: tun_chr_poll\n", tun->name); poll_wait(file, &tun->read_wait, wait); if (skb_queue_len(&tun->readq)) mask |= POLLIN | POLLRDNORM; return mask; } /* Get packet from user space buffer(already verified) */ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count) { struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) }; struct sk_buff *skb; size_t len = count; if (!(tun->flags & TUN_NO_PI)) { if ((len -= sizeof(pi)) > count) return -EINVAL; memcpy_fromiovec((void *)&pi, iv, sizeof(pi)); } if (!(skb = alloc_skb(len + 2, GFP_KERNEL))) { tun->stats.rx_dropped++; return -ENOMEM; } skb_reserve(skb, 2); memcpy_fromiovec(skb_put(skb, len), iv, len); skb->dev = &tun->dev; switch (tun->flags & TUN_TYPE_MASK) { case TUN_TUN_DEV: skb->mac.raw = skb->data; skb->protocol = pi.proto; break; case TUN_TAP_DEV: skb->protocol = eth_type_trans(skb, &tun->dev); break; }; if (tun->flags & TUN_NOCHECKSUM) skb->ip_summed = CHECKSUM_UNNECESSARY; netif_rx_ni(skb); tun->stats.rx_packets++; tun->stats.rx_bytes += len; return count; } /* Writev */ static ssize_t tun_chr_writev(struct file * file, const struct iovec *iv, unsigned long count, loff_t *pos) { struct tun_struct *tun = (struct tun_struct *)file->private_data; unsigned long i; size_t len; if (!tun) return -EBADFD; DBG(KERN_INFO "%s: tun_chr_write %d\n", tun->name, count); for (i = 0, len = 0; i < count; i++) { if (verify_area(VERIFY_READ, iv[i].iov_base, iv[i].iov_len)) return -EFAULT; len += iv[i].iov_len; } return tun_get_user(tun, (struct iovec *) iv, len); } /* Write */ static ssize_t tun_chr_write(struct file * file, const char * buf, size_t count, loff_t *pos) { struct iovec iv = { (void *) buf, count }; return tun_chr_writev(file, &iv, 1, pos); } /* Put packet to the user space buffer (already verified) */ static __inline__ ssize_t tun_put_user(struct tun_struct *tun, struct sk_buff *skb, struct iovec *iv, int len) { struct tun_pi pi = { 0, skb->protocol }; ssize_t total = 0; if (!(tun->flags & TUN_NO_PI)) { if ((len -= sizeof(pi)) < 0) return -EINVAL; if (len < skb->len) { /* Packet will be striped */ pi.flags |= TUN_PKT_STRIP; } memcpy_toiovec(iv, (void *) &pi, sizeof(pi)); total += sizeof(pi); } len = MIN(skb->len, len); skb_copy_datagram_iovec(skb, 0, iv, len); total += len; tun->stats.tx_packets++; tun->stats.tx_bytes += len; return total; } /* Readv */ static ssize_t tun_chr_readv(struct file *file, const struct iovec *iv, unsigned long count, loff_t *pos) { struct tun_struct *tun = (struct tun_struct *)file->private_data; DECLARE_WAITQUEUE(wait, current); struct sk_buff *skb; ssize_t len, ret = 0; unsigned long i; if (!tun) return -EBADFD; DBG(KERN_INFO "%s: tun_chr_read\n", tun->name); for (i = 0, len = 0; i < count; i++) { if (verify_area(VERIFY_WRITE, iv[i].iov_base, iv[i].iov_len)) return -EFAULT; len += iv[i].iov_len; } add_wait_queue(&tun->read_wait, &wait); while (len) { current->state = TASK_INTERRUPTIBLE; /* Read frames from the queue */ if (!(skb=skb_dequeue(&tun->readq))) { if (file->f_flags & O_NONBLOCK) { ret = -EAGAIN; break; } if (signal_pending(current)) { ret = -ERESTARTSYS; break; } /* Nothing to read, let's sleep */ schedule(); continue; } netif_start_queue(&tun->dev); ret = tun_put_user(tun, skb, (struct iovec *) iv, len); kfree_skb(skb); break; } current->state = TASK_RUNNING; remove_wait_queue(&tun->read_wait, &wait); return ret; } /* Read */ static ssize_t tun_chr_read(struct file * file, char * buf, size_t count, loff_t *pos) { struct iovec iv = { buf, count }; return tun_chr_readv(file, &iv, 1, pos); } static int tun_set_iff(struct file *file, struct ifreq *ifr) { struct tun_struct *tun; struct net_device *dev; int err; dev = __dev_get_by_name(ifr->ifr_name); if (dev) { /* Device exist */ tun = dev->priv; if (dev->init != tun_net_init || tun->attached) return -EBUSY; /* Check permissions */ if (tun->owner != -1) if (current->euid != tun->owner && !capable(CAP_NET_ADMIN)) return -EPERM; } else { char *name; /* Allocate new device */ if (!(tun = kmalloc(sizeof(struct tun_struct), GFP_KERNEL)) ) return -ENOMEM; memset(tun, 0, sizeof(struct tun_struct)); skb_queue_head_init(&tun->readq); init_waitqueue_head(&tun->read_wait); tun->owner = -1; tun->dev.init = tun_net_init; tun->dev.priv = tun; err = -EINVAL; /* Set dev type */ if (ifr->ifr_flags & IFF_TUN) { /* TUN device */ tun->flags |= TUN_TUN_DEV; name = "tun%d"; } else if (ifr->ifr_flags & IFF_TAP) { /* TAP device */ tun->flags |= TUN_TAP_DEV; name = "tap%d"; } else goto failed; if (*ifr->ifr_name) name = ifr->ifr_name; if ((err = dev_alloc_name(&tun->dev, name)) < 0) goto failed; if ((err = register_netdevice(&tun->dev))) goto failed; MOD_INC_USE_COUNT; tun->name = tun->dev.name; } DBG(KERN_INFO "%s: tun_set_iff\n", tun->name); if (ifr->ifr_flags & IFF_NO_PI) tun->flags |= TUN_NO_PI; if (ifr->ifr_flags & IFF_ONE_QUEUE) tun->flags |= TUN_ONE_QUEUE; file->private_data = tun; tun->attached = 1; strcpy(ifr->ifr_name, tun->name); return 0; failed: kfree(tun); return err; } static int tun_chr_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { struct tun_struct *tun = (struct tun_struct *)file->private_data; if (cmd == TUNSETIFF && !tun) { struct ifreq ifr; int err; if (copy_from_user(&ifr, (void *)arg, sizeof(ifr))) return -EFAULT; ifr.ifr_name[IFNAMSIZ-1] = '\0'; rtnl_lock(); err = tun_set_iff(file, &ifr); rtnl_unlock(); if (err) return err; copy_to_user((void *)arg, &ifr, sizeof(ifr)); return 0; } if (!tun) return -EBADFD; DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->name, cmd); switch (cmd) { case TUNSETNOCSUM: /* Disable/Enable checksum */ if (arg) tun->flags |= TUN_NOCHECKSUM; else tun->flags &= ~TUN_NOCHECKSUM; DBG(KERN_INFO "%s: checksum %s\n", tun->name, arg ? "disabled" : "enabled"); break; case TUNSETPERSIST: /* Disable/Enable persist mode */ if (arg) tun->flags |= TUN_PERSIST; else tun->flags &= ~TUN_PERSIST; DBG(KERN_INFO "%s: persist %s\n", tun->name, arg ? "disabled" : "enabled"); break; case TUNSETOWNER: /* Set owner of the device */ tun->owner = (uid_t) arg; DBG(KERN_INFO "%s: owner set to %d\n", tun->owner); break; #ifdef TUN_DEBUG case TUNSETDEBUG: tun->debug = arg; break; #endif default: return -EINVAL; }; return 0; } static int tun_chr_fasync(int fd, struct file *file, int on) { struct tun_struct *tun = (struct tun_struct *)file->private_data; int ret; if (!tun) return -EBADFD; DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->name, on); if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0) return ret; if (on) { tun->flags |= TUN_FASYNC; if (!file->f_owner.pid) { file->f_owner.pid = current->pid; file->f_owner.uid = current->uid; file->f_owner.euid = current->euid; } } else tun->flags &= ~TUN_FASYNC; return 0; } static int tun_chr_open(struct inode *inode, struct file * file) { DBG1(KERN_INFO "tunX: tun_chr_open\n"); file->private_data = NULL; return 0; } static int tun_chr_close(struct inode *inode, struct file *file) { struct tun_struct *tun = (struct tun_struct *)file->private_data; if (!tun) return 0; DBG(KERN_INFO "%s: tun_chr_close\n", tun->name); tun_chr_fasync(-1, file, 0); rtnl_lock(); /* Detach from net device */ file->private_data = NULL; tun->attached = 0; /* Drop read queue */ skb_queue_purge(&tun->readq); if (!(tun->flags & TUN_PERSIST)) { dev_close(&tun->dev); unregister_netdevice(&tun->dev); kfree(tun); MOD_DEC_USE_COUNT; } rtnl_unlock(); return 0; } static struct file_operations tun_fops = { owner: THIS_MODULE, llseek: no_llseek, read: tun_chr_read, readv: tun_chr_readv, write: tun_chr_write, writev: tun_chr_writev, poll: tun_chr_poll, ioctl: tun_chr_ioctl, open: tun_chr_open, release:tun_chr_close, fasync: tun_chr_fasync }; static struct miscdevice tun_miscdev= { TUN_MINOR, "net/tun", &tun_fops }; int __init tun_init(void) { printk(KERN_INFO "Universal TUN/TAP device driver %s " "(C)1999-2002 Maxim Krasnyansky\n", TUN_VER); if (misc_register(&tun_miscdev)) { printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR); return -EIO; } return 0; } void tun_cleanup(void) { misc_deregister(&tun_miscdev); } module_init(tun_init); module_exit(tun_cleanup); MODULE_LICENSE("GPL");