/* * Generic PPP layer for Linux. * * Copyright 1999-2002 Paul Mackerras. * * 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. * * The generic PPP layer handles the PPP network interfaces, the * /dev/ppp device, packet and VJ compression, and multilink. * It talks to PPP `channels' via the interface defined in * include/linux/ppp_channel.h. Channels provide the basic means for * sending and receiving PPP frames on some kind of communications * channel. * * Part of the code in this driver was inspired by the old async-only * PPP driver, written by Michael Callahan and Al Longyear, and * subsequently hacked by Paul Mackerras. * * ==FILEVERSION 20041108== */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define PPP_VERSION "2.4.2" /* * Network protocols we support. */ #define NP_IP 0 /* Internet Protocol V4 */ #define NP_IPV6 1 /* Internet Protocol V6 */ #define NP_IPX 2 /* IPX protocol */ #define NP_AT 3 /* Appletalk protocol */ #define NP_MPLS_UC 4 /* MPLS unicast */ #define NP_MPLS_MC 5 /* MPLS multicast */ #define NUM_NP 6 /* Number of NPs. */ #define MPHDRLEN 6 /* multilink protocol header length */ #define MPHDRLEN_SSN 4 /* ditto with short sequence numbers */ #define MIN_FRAG_SIZE 64 /* * An instance of /dev/ppp can be associated with either a ppp * interface unit or a ppp channel. In both cases, file->private_data * points to one of these. */ struct ppp_file { enum { INTERFACE=1, CHANNEL } kind; struct sk_buff_head xq; /* pppd transmit queue */ struct sk_buff_head rq; /* receive queue for pppd */ wait_queue_head_t rwait; /* for poll on reading /dev/ppp */ atomic_t refcnt; /* # refs (incl /dev/ppp attached) */ int hdrlen; /* space to leave for headers */ int index; /* interface unit / channel number */ int dead; /* unit/channel has been shut down */ }; #define PF_TO_X(pf, X) ((X *)((char *)(pf) - offsetof(X, file))) #define PF_TO_PPP(pf) PF_TO_X(pf, struct ppp) #define PF_TO_CHANNEL(pf) PF_TO_X(pf, struct channel) #define ROUNDUP(n, x) (((n) + (x) - 1) / (x)) /* * Data structure describing one ppp unit. * A ppp unit corresponds to a ppp network interface device * and represents a multilink bundle. * It can have 0 or more ppp channels connected to it. */ struct ppp { struct ppp_file file; /* stuff for read/write/poll 0 */ struct file *owner; /* file that owns this unit 48 */ struct list_head channels; /* list of attached channels 4c */ int n_channels; /* how many channels are attached 54 */ spinlock_t rlock; /* lock for receive side 58 */ spinlock_t wlock; /* lock for transmit side 5c */ int mru; /* max receive unit 60 */ unsigned int flags; /* control bits 64 */ unsigned int xstate; /* transmit state bits 68 */ unsigned int rstate; /* receive state bits 6c */ int debug; /* debug flags 70 */ struct slcompress *vj; /* state for VJ header compression */ enum NPmode npmode[NUM_NP]; /* what to do with each net proto 78 */ struct sk_buff *xmit_pending; /* a packet ready to go out 88 */ struct compressor *xcomp; /* transmit packet compressor 8c */ void *xc_state; /* its internal state 90 */ struct compressor *rcomp; /* receive decompressor 94 */ void *rc_state; /* its internal state 98 */ unsigned long last_xmit; /* jiffies when last pkt sent 9c */ unsigned long last_recv; /* jiffies when last pkt rcvd a0 */ struct net_device *dev; /* network interface device a4 */ #ifdef CONFIG_PPP_MULTILINK int nxchan; /* next channel to send something on */ u32 nxseq; /* next sequence number to send */ int mrru; /* MP: max reconst. receive unit */ u32 nextseq; /* MP: seq no of next packet */ u32 minseq; /* MP: min of most recent seqnos */ struct sk_buff_head mrq; /* MP: receive reconstruction queue */ #endif /* CONFIG_PPP_MULTILINK */ struct net_device_stats stats; /* statistics */ #ifdef CONFIG_PPP_FILTER struct sock_filter *pass_filter; /* filter for packets to pass */ struct sock_filter *active_filter;/* filter for pkts to reset idle */ unsigned pass_len, active_len; #endif /* CONFIG_PPP_FILTER */ }; /* * Bits in flags: SC_NO_TCP_CCID, SC_CCP_OPEN, SC_CCP_UP, SC_LOOP_TRAFFIC, * SC_MULTILINK, SC_MP_SHORTSEQ, SC_MP_XSHORTSEQ, SC_COMP_TCP, SC_REJ_COMP_TCP, * SC_MUST_COMP * Bits in rstate: SC_DECOMP_RUN, SC_DC_ERROR, SC_DC_FERROR. * Bits in xstate: SC_COMP_RUN */ #define SC_FLAG_BITS (SC_NO_TCP_CCID|SC_CCP_OPEN|SC_CCP_UP|SC_LOOP_TRAFFIC \ |SC_MULTILINK|SC_MP_SHORTSEQ|SC_MP_XSHORTSEQ \ |SC_COMP_TCP|SC_REJ_COMP_TCP|SC_MUST_COMP) /* * Private data structure for each channel. * This includes the data structure used for multilink. */ struct channel { struct ppp_file file; /* stuff for read/write/poll */ struct list_head list; /* link in all/new_channels list */ struct ppp_channel *chan; /* public channel data structure */ struct rw_semaphore chan_sem; /* protects `chan' during chan ioctl */ spinlock_t downl; /* protects `chan', file.xq dequeue */ struct ppp *ppp; /* ppp unit we're connected to */ struct list_head clist; /* link in list of channels per unit */ rwlock_t upl; /* protects `ppp' */ #ifdef CONFIG_PPP_MULTILINK u8 avail; /* flag used in multilink stuff */ u8 had_frag; /* >= 1 fragments have been sent */ u32 lastseq; /* MP: last sequence # received */ #endif /* CONFIG_PPP_MULTILINK */ }; /* * SMP locking issues: * Both the ppp.rlock and ppp.wlock locks protect the ppp.channels * list and the ppp.n_channels field, you need to take both locks * before you modify them. * The lock ordering is: channel.upl -> ppp.wlock -> ppp.rlock -> * channel.downl. */ /* * A cardmap represents a mapping from unsigned integers to pointers, * and provides a fast "find lowest unused number" operation. * It uses a broad (32-way) tree with a bitmap at each level. * It is designed to be space-efficient for small numbers of entries * and time-efficient for large numbers of entries. */ #define CARDMAP_ORDER 5 #define CARDMAP_WIDTH (1U << CARDMAP_ORDER) #define CARDMAP_MASK (CARDMAP_WIDTH - 1) struct cardmap { int shift; unsigned long inuse; struct cardmap *parent; void *ptr[CARDMAP_WIDTH]; }; static void *cardmap_get(struct cardmap *map, unsigned int nr); static int cardmap_set(struct cardmap **map, unsigned int nr, void *ptr); static unsigned int cardmap_find_first_free(struct cardmap *map); static void cardmap_destroy(struct cardmap **map); /* * all_ppp_mutex protects the all_ppp_units mapping. * It also ensures that finding a ppp unit in the all_ppp_units map * and updating its file.refcnt field is atomic. */ static DEFINE_MUTEX(all_ppp_mutex); static struct cardmap *all_ppp_units; static atomic_t ppp_unit_count = ATOMIC_INIT(0); /* * all_channels_lock protects all_channels and last_channel_index, * and the atomicity of find a channel and updating its file.refcnt * field. */ static DEFINE_SPINLOCK(all_channels_lock); static LIST_HEAD(all_channels); static LIST_HEAD(new_channels); static int last_channel_index; static atomic_t channel_count = ATOMIC_INIT(0); /* Get the PPP protocol number from a skb */ #define PPP_PROTO(skb) (((skb)->data[0] << 8) + (skb)->data[1]) /* We limit the length of ppp->file.rq to this (arbitrary) value */ #define PPP_MAX_RQLEN 32 /* * Maximum number of multilink fragments queued up. * This has to be large enough to cope with the maximum latency of * the slowest channel relative to the others. Strictly it should * depend on the number of channels and their characteristics. */ #define PPP_MP_MAX_QLEN 128 /* Multilink header bits. */ #define B 0x80 /* this fragment begins a packet */ #define E 0x40 /* this fragment ends a packet */ /* Compare multilink sequence numbers (assumed to be 32 bits wide) */ #define seq_before(a, b) ((s32)((a) - (b)) < 0) #define seq_after(a, b) ((s32)((a) - (b)) > 0) /* Prototypes. */ static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file, unsigned int cmd, unsigned long arg); static void ppp_xmit_process(struct ppp *ppp); static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb); static void ppp_push(struct ppp *ppp); static void ppp_channel_push(struct channel *pch); static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch); static void ppp_receive_error(struct ppp *ppp); static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb); static struct sk_buff *ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb); #ifdef CONFIG_PPP_MULTILINK static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch); static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb); static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp); static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb); #endif /* CONFIG_PPP_MULTILINK */ static int ppp_set_compress(struct ppp *ppp, unsigned long arg); static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound); static void ppp_ccp_closed(struct ppp *ppp); static struct compressor *find_compressor(int type); static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st); static struct ppp *ppp_create_interface(int unit, int *retp); static void init_ppp_file(struct ppp_file *pf, int kind); static void ppp_shutdown_interface(struct ppp *ppp); static void ppp_destroy_interface(struct ppp *ppp); static struct ppp *ppp_find_unit(int unit); static struct channel *ppp_find_channel(int unit); static int ppp_connect_channel(struct channel *pch, int unit); static int ppp_disconnect_channel(struct channel *pch); static void ppp_destroy_channel(struct channel *pch); static struct class *ppp_class; /* Translates a PPP protocol number to a NP index (NP == network protocol) */ static inline int proto_to_npindex(int proto) { switch (proto) { case PPP_IP: return NP_IP; case PPP_IPV6: return NP_IPV6; case PPP_IPX: return NP_IPX; case PPP_AT: return NP_AT; case PPP_MPLS_UC: return NP_MPLS_UC; case PPP_MPLS_MC: return NP_MPLS_MC; } return -EINVAL; } /* Translates an NP index into a PPP protocol number */ static const int npindex_to_proto[NUM_NP] = { PPP_IP, PPP_IPV6, PPP_IPX, PPP_AT, PPP_MPLS_UC, PPP_MPLS_MC, }; /* Translates an ethertype into an NP index */ static inline int ethertype_to_npindex(int ethertype) { switch (ethertype) { case ETH_P_IP: return NP_IP; case ETH_P_IPV6: return NP_IPV6; case ETH_P_IPX: return NP_IPX; case ETH_P_PPPTALK: case ETH_P_ATALK: return NP_AT; case ETH_P_MPLS_UC: return NP_MPLS_UC; case ETH_P_MPLS_MC: return NP_MPLS_MC; } return -1; } /* Translates an NP index into an ethertype */ static const int npindex_to_ethertype[NUM_NP] = { ETH_P_IP, ETH_P_IPV6, ETH_P_IPX, ETH_P_PPPTALK, ETH_P_MPLS_UC, ETH_P_MPLS_MC, }; /* * Locking shorthand. */ #define ppp_xmit_lock(ppp) spin_lock_bh(&(ppp)->wlock) #define ppp_xmit_unlock(ppp) spin_unlock_bh(&(ppp)->wlock) #define ppp_recv_lock(ppp) spin_lock_bh(&(ppp)->rlock) #define ppp_recv_unlock(ppp) spin_unlock_bh(&(ppp)->rlock) #define ppp_lock(ppp) do { ppp_xmit_lock(ppp); \ ppp_recv_lock(ppp); } while (0) #define ppp_unlock(ppp) do { ppp_recv_unlock(ppp); \ ppp_xmit_unlock(ppp); } while (0) /* * /dev/ppp device routines. * The /dev/ppp device is used by pppd to control the ppp unit. * It supports the read, write, ioctl and poll functions. * Open instances of /dev/ppp can be in one of three states: * unattached, attached to a ppp unit, or attached to a ppp channel. */ static int ppp_open(struct inode *inode, struct file *file) { /* * This could (should?) be enforced by the permissions on /dev/ppp. */ if (!capable(CAP_NET_ADMIN)) return -EPERM; return 0; } static int ppp_release(struct inode *inode, struct file *file) { struct ppp_file *pf = file->private_data; struct ppp *ppp; if (pf != 0) { file->private_data = NULL; if (pf->kind == INTERFACE) { ppp = PF_TO_PPP(pf); if (file == ppp->owner) ppp_shutdown_interface(ppp); } if (atomic_dec_and_test(&pf->refcnt)) { switch (pf->kind) { case INTERFACE: ppp_destroy_interface(PF_TO_PPP(pf)); break; case CHANNEL: ppp_destroy_channel(PF_TO_CHANNEL(pf)); break; } } } return 0; } static ssize_t ppp_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct ppp_file *pf = file->private_data; DECLARE_WAITQUEUE(wait, current); ssize_t ret; struct sk_buff *skb = NULL; ret = count; if (pf == 0) return -ENXIO; add_wait_queue(&pf->rwait, &wait); for (;;) { set_current_state(TASK_INTERRUPTIBLE); skb = skb_dequeue(&pf->rq); if (skb) break; ret = 0; if (pf->dead) break; if (pf->kind == INTERFACE) { /* * Return 0 (EOF) on an interface that has no * channels connected, unless it is looping * network traffic (demand mode). */ struct ppp *ppp = PF_TO_PPP(pf); if (ppp->n_channels == 0 && (ppp->flags & SC_LOOP_TRAFFIC) == 0) break; } ret = -EAGAIN; if (file->f_flags & O_NONBLOCK) break; ret = -ERESTARTSYS; if (signal_pending(current)) break; schedule(); } set_current_state(TASK_RUNNING); remove_wait_queue(&pf->rwait, &wait); if (skb == 0) goto out; ret = -EOVERFLOW; if (skb->len > count) goto outf; ret = -EFAULT; if (copy_to_user(buf, skb->data, skb->len)) goto outf; ret = skb->len; outf: kfree_skb(skb); out: return ret; } static ssize_t ppp_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct ppp_file *pf = file->private_data; struct sk_buff *skb; ssize_t ret; if (pf == 0) return -ENXIO; ret = -ENOMEM; skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL); if (skb == 0) goto out; skb_reserve(skb, pf->hdrlen); ret = -EFAULT; if (copy_from_user(skb_put(skb, count), buf, count)) { kfree_skb(skb); goto out; } skb_queue_tail(&pf->xq, skb); switch (pf->kind) { case INTERFACE: ppp_xmit_process(PF_TO_PPP(pf)); break; case CHANNEL: ppp_channel_push(PF_TO_CHANNEL(pf)); break; } ret = count; out: return ret; } /* No kernel lock - fine */ static unsigned int ppp_poll(struct file *file, poll_table *wait) { struct ppp_file *pf = file->private_data; unsigned int mask; if (pf == 0) return 0; poll_wait(file, &pf->rwait, wait); mask = POLLOUT | POLLWRNORM; if (skb_peek(&pf->rq) != 0) mask |= POLLIN | POLLRDNORM; if (pf->dead) mask |= POLLHUP; else if (pf->kind == INTERFACE) { /* see comment in ppp_read */ struct ppp *ppp = PF_TO_PPP(pf); if (ppp->n_channels == 0 && (ppp->flags & SC_LOOP_TRAFFIC) == 0) mask |= POLLIN | POLLRDNORM; } return mask; } #ifdef CONFIG_PPP_FILTER static int get_filter(void __user *arg, struct sock_filter **p) { struct sock_fprog uprog; struct sock_filter *code = NULL; int len, err; if (copy_from_user(&uprog, arg, sizeof(uprog))) return -EFAULT; if (!uprog.len) { *p = NULL; return 0; } len = uprog.len * sizeof(struct sock_filter); code = kmalloc(len, GFP_KERNEL); if (code == NULL) return -ENOMEM; if (copy_from_user(code, uprog.filter, len)) { kfree(code); return -EFAULT; } err = sk_chk_filter(code, uprog.len); if (err) { kfree(code); return err; } *p = code; return uprog.len; } #endif /* CONFIG_PPP_FILTER */ static int ppp_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { struct ppp_file *pf = file->private_data; struct ppp *ppp; int err = -EFAULT, val, val2, i; struct ppp_idle idle; struct npioctl npi; int unit, cflags; struct slcompress *vj; void __user *argp = (void __user *)arg; int __user *p = argp; if (pf == 0) return ppp_unattached_ioctl(pf, file, cmd, arg); if (cmd == PPPIOCDETACH) { /* * We have to be careful here... if the file descriptor * has been dup'd, we could have another process in the * middle of a poll using the same file *, so we had * better not free the interface data structures - * instead we fail the ioctl. Even in this case, we * shut down the interface if we are the owner of it. * Actually, we should get rid of PPPIOCDETACH, userland * (i.e. pppd) could achieve the same effect by closing * this fd and reopening /dev/ppp. */ err = -EINVAL; if (pf->kind == INTERFACE) { ppp = PF_TO_PPP(pf); if (file == ppp->owner) ppp_shutdown_interface(ppp); } if (atomic_read(&file->f_count) <= 2) { ppp_release(inode, file); err = 0; } else printk(KERN_DEBUG "PPPIOCDETACH file->f_count=%d\n", atomic_read(&file->f_count)); return err; } if (pf->kind == CHANNEL) { struct channel *pch = PF_TO_CHANNEL(pf); struct ppp_channel *chan; switch (cmd) { case PPPIOCCONNECT: if (get_user(unit, p)) break; err = ppp_connect_channel(pch, unit); break; case PPPIOCDISCONN: err = ppp_disconnect_channel(pch); break; default: down_read(&pch->chan_sem); chan = pch->chan; err = -ENOTTY; if (chan && chan->ops->ioctl) err = chan->ops->ioctl(chan, cmd, arg); up_read(&pch->chan_sem); } return err; } if (pf->kind != INTERFACE) { /* can't happen */ printk(KERN_ERR "PPP: not interface or channel??\n"); return -EINVAL; } ppp = PF_TO_PPP(pf); switch (cmd) { case PPPIOCSMRU: if (get_user(val, p)) break; ppp->mru = val; err = 0; break; case PPPIOCSFLAGS: if (get_user(val, p)) break; ppp_lock(ppp); cflags = ppp->flags & ~val; ppp->flags = val & SC_FLAG_BITS; ppp_unlock(ppp); if (cflags & SC_CCP_OPEN) ppp_ccp_closed(ppp); err = 0; break; case PPPIOCGFLAGS: val = ppp->flags | ppp->xstate | ppp->rstate; if (put_user(val, p)) break; err = 0; break; case PPPIOCSCOMPRESS: err = ppp_set_compress(ppp, arg); break; case PPPIOCGUNIT: if (put_user(ppp->file.index, p)) break; err = 0; break; case PPPIOCSDEBUG: if (get_user(val, p)) break; ppp->debug = val; err = 0; break; case PPPIOCGDEBUG: if (put_user(ppp->debug, p)) break; err = 0; break; case PPPIOCGIDLE: idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ; idle.recv_idle = (jiffies - ppp->last_recv) / HZ; if (copy_to_user(argp, &idle, sizeof(idle))) break; err = 0; break; case PPPIOCSMAXCID: if (get_user(val, p)) break; val2 = 15; if ((val >> 16) != 0) { val2 = val >> 16; val &= 0xffff; } vj = slhc_init(val2+1, val+1); if (vj == 0) { printk(KERN_ERR "PPP: no memory (VJ compressor)\n"); err = -ENOMEM; break; } ppp_lock(ppp); if (ppp->vj != 0) slhc_free(ppp->vj); ppp->vj = vj; ppp_unlock(ppp); err = 0; break; case PPPIOCGNPMODE: case PPPIOCSNPMODE: if (copy_from_user(&npi, argp, sizeof(npi))) break; err = proto_to_npindex(npi.protocol); if (err < 0) break; i = err; if (cmd == PPPIOCGNPMODE) { err = -EFAULT; npi.mode = ppp->npmode[i]; if (copy_to_user(argp, &npi, sizeof(npi))) break; } else { ppp->npmode[i] = npi.mode; /* we may be able to transmit more packets now (??) */ netif_wake_queue(ppp->dev); } err = 0; break; #ifdef CONFIG_PPP_FILTER case PPPIOCSPASS: { struct sock_filter *code; err = get_filter(argp, &code); if (err >= 0) { ppp_lock(ppp); kfree(ppp->pass_filter); ppp->pass_filter = code; ppp->pass_len = err; ppp_unlock(ppp); err = 0; } break; } case PPPIOCSACTIVE: { struct sock_filter *code; err = get_filter(argp, &code); if (err >= 0) { ppp_lock(ppp); kfree(ppp->active_filter); ppp->active_filter = code; ppp->active_len = err; ppp_unlock(ppp); err = 0; } break; } #endif /* CONFIG_PPP_FILTER */ #ifdef CONFIG_PPP_MULTILINK case PPPIOCSMRRU: if (get_user(val, p)) break; ppp_recv_lock(ppp); ppp->mrru = val; ppp_recv_unlock(ppp); err = 0; break; #endif /* CONFIG_PPP_MULTILINK */ default: err = -ENOTTY; } return err; } static int ppp_unattached_ioctl(struct ppp_file *pf, struct file *file, unsigned int cmd, unsigned long arg) { int unit, err = -EFAULT; struct ppp *ppp; struct channel *chan; int __user *p = (int __user *)arg; switch (cmd) { case PPPIOCNEWUNIT: /* Create a new ppp unit */ if (get_user(unit, p)) break; ppp = ppp_create_interface(unit, &err); if (ppp == 0) break; file->private_data = &ppp->file; ppp->owner = file; err = -EFAULT; if (put_user(ppp->file.index, p)) break; err = 0; break; case PPPIOCATTACH: /* Attach to an existing ppp unit */ if (get_user(unit, p)) break; mutex_lock(&all_ppp_mutex); err = -ENXIO; ppp = ppp_find_unit(unit); if (ppp != 0) { atomic_inc(&ppp->file.refcnt); file->private_data = &ppp->file; err = 0; } mutex_unlock(&all_ppp_mutex); break; case PPPIOCATTCHAN: if (get_user(unit, p)) break; spin_lock_bh(&all_channels_lock); err = -ENXIO; chan = ppp_find_channel(unit); if (chan != 0) { atomic_inc(&chan->file.refcnt); file->private_data = &chan->file; err = 0; } spin_unlock_bh(&all_channels_lock); break; default: err = -ENOTTY; } return err; } static struct file_operations ppp_device_fops = { .owner = THIS_MODULE, .read = ppp_read, .write = ppp_write, .poll = ppp_poll, .ioctl = ppp_ioctl, .open = ppp_open, .release = ppp_release }; #define PPP_MAJOR 108 /* Called at boot time if ppp is compiled into the kernel, or at module load time (from init_module) if compiled as a module. */ static int __init ppp_init(void) { int err; printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n"); err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops); if (!err) { ppp_class = class_create(THIS_MODULE, "ppp"); if (IS_ERR(ppp_class)) { err = PTR_ERR(ppp_class); goto out_chrdev; } class_device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp"); } out: if (err) printk(KERN_ERR "failed to register PPP device (%d)\n", err); return err; out_chrdev: unregister_chrdev(PPP_MAJOR, "ppp"); goto out; } /* * Network interface unit routines. */ static int ppp_start_xmit(struct sk_buff *skb, struct net_device *dev) { struct ppp *ppp = (struct ppp *) dev->priv; int npi, proto; unsigned char *pp; npi = ethertype_to_npindex(ntohs(skb->protocol)); if (npi < 0) goto outf; /* Drop, accept or reject the packet */ switch (ppp->npmode[npi]) { case NPMODE_PASS: break; case NPMODE_QUEUE: /* it would be nice to have a way to tell the network system to queue this one up for later. */ goto outf; case NPMODE_DROP: case NPMODE_ERROR: goto outf; } /* Put the 2-byte PPP protocol number on the front, making sure there is room for the address and control fields. */ if (skb_headroom(skb) < PPP_HDRLEN) { struct sk_buff *ns; ns = alloc_skb(skb->len + dev->hard_header_len, GFP_ATOMIC); if (ns == 0) goto outf; skb_reserve(ns, dev->hard_header_len); skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len); kfree_skb(skb); skb = ns; } pp = skb_push(skb, 2); proto = npindex_to_proto[npi]; pp[0] = proto >> 8; pp[1] = proto; netif_stop_queue(dev); skb_queue_tail(&ppp->file.xq, skb); ppp_xmit_process(ppp); return 0; outf: kfree_skb(skb); ++ppp->stats.tx_dropped; return 0; } static struct net_device_stats * ppp_net_stats(struct net_device *dev) { struct ppp *ppp = (struct ppp *) dev->priv; return &ppp->stats; } static int ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) { struct ppp *ppp = dev->priv; int err = -EFAULT; void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data; struct ppp_stats stats; struct ppp_comp_stats cstats; char *vers; switch (cmd) { case SIOCGPPPSTATS: ppp_get_stats(ppp, &stats); if (copy_to_user(addr, &stats, sizeof(stats))) break; err = 0; break; case SIOCGPPPCSTATS: memset(&cstats, 0, sizeof(cstats)); if (ppp->xc_state != 0) ppp->xcomp->comp_stat(ppp->xc_state, &cstats.c); if (ppp->rc_state != 0) ppp->rcomp->decomp_stat(ppp->rc_state, &cstats.d); if (copy_to_user(addr, &cstats, sizeof(cstats))) break; err = 0; break; case SIOCGPPPVER: vers = PPP_VERSION; if (copy_to_user(addr, vers, strlen(vers) + 1)) break; err = 0; break; default: err = -EINVAL; } return err; } static void ppp_setup(struct net_device *dev) { dev->hard_header_len = PPP_HDRLEN; dev->mtu = PPP_MTU; dev->addr_len = 0; dev->tx_queue_len = 3; dev->type = ARPHRD_PPP; dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; } /* * Transmit-side routines. */ /* * Called to do any work queued up on the transmit side * that can now be done. */ static void ppp_xmit_process(struct ppp *ppp) { struct sk_buff *skb; ppp_xmit_lock(ppp); if (ppp->dev != 0) { ppp_push(ppp); while (ppp->xmit_pending == 0 && (skb = skb_dequeue(&ppp->file.xq)) != 0) ppp_send_frame(ppp, skb); /* If there's no work left to do, tell the core net code that we can accept some more. */ if (ppp->xmit_pending == 0 && skb_peek(&ppp->file.xq) == 0) netif_wake_queue(ppp->dev); } ppp_xmit_unlock(ppp); } static inline struct sk_buff * pad_compress_skb(struct ppp *ppp, struct sk_buff *skb) { struct sk_buff *new_skb; int len; int new_skb_size = ppp->dev->mtu + ppp->xcomp->comp_extra + ppp->dev->hard_header_len; int compressor_skb_size = ppp->dev->mtu + ppp->xcomp->comp_extra + PPP_HDRLEN; new_skb = alloc_skb(new_skb_size, GFP_ATOMIC); if (!new_skb) { if (net_ratelimit()) printk(KERN_ERR "PPP: no memory (comp pkt)\n"); return NULL; } if (ppp->dev->hard_header_len > PPP_HDRLEN) skb_reserve(new_skb, ppp->dev->hard_header_len - PPP_HDRLEN); /* compressor still expects A/C bytes in hdr */ len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2, new_skb->data, skb->len + 2, compressor_skb_size); if (len > 0 && (ppp->flags & SC_CCP_UP)) { kfree_skb(skb); skb = new_skb; skb_put(skb, len); skb_pull(skb, 2); /* pull off A/C bytes */ } else if (len == 0) { /* didn't compress, or CCP not up yet */ kfree_skb(new_skb); new_skb = skb; } else { /* * (len < 0) * MPPE requires that we do not send unencrypted * frames. The compressor will return -1 if we * should drop the frame. We cannot simply test * the compress_proto because MPPE and MPPC share * the same number. */ if (net_ratelimit()) printk(KERN_ERR "ppp: compressor dropped pkt\n"); kfree_skb(skb); kfree_skb(new_skb); new_skb = NULL; } return new_skb; } /* * Compress and send a frame. * The caller should have locked the xmit path, * and xmit_pending should be 0. */ static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb) { int proto = PPP_PROTO(skb); struct sk_buff *new_skb; int len; unsigned char *cp; if (proto < 0x8000) { #ifdef CONFIG_PPP_FILTER /* check if we should pass this packet */ /* the filter instructions are constructed assuming a four-byte PPP header on each packet */ *skb_push(skb, 2) = 1; if (ppp->pass_filter && sk_run_filter(skb, ppp->pass_filter, ppp->pass_len) == 0) { if (ppp->debug & 1) printk(KERN_DEBUG "PPP: outbound frame not passed\n"); kfree_skb(skb); return; } /* if this packet passes the active filter, record the time */ if (!(ppp->active_filter && sk_run_filter(skb, ppp->active_filter, ppp->active_len) == 0)) ppp->last_xmit = jiffies; skb_pull(skb, 2); #else /* for data packets, record the time */ ppp->last_xmit = jiffies; #endif /* CONFIG_PPP_FILTER */ } ++ppp->stats.tx_packets; ppp->stats.tx_bytes += skb->len - 2; switch (proto) { case PPP_IP: if (ppp->vj == 0 || (ppp->flags & SC_COMP_TCP) == 0) break; /* try to do VJ TCP header compression */ new_skb = alloc_skb(skb->len + ppp->dev->hard_header_len - 2, GFP_ATOMIC); if (new_skb == 0) { printk(KERN_ERR "PPP: no memory (VJ comp pkt)\n"); goto drop; } skb_reserve(new_skb, ppp->dev->hard_header_len - 2); cp = skb->data + 2; len = slhc_compress(ppp->vj, cp, skb->len - 2, new_skb->data + 2, &cp, !(ppp->flags & SC_NO_TCP_CCID)); if (cp == skb->data + 2) { /* didn't compress */ kfree_skb(new_skb); } else { if (cp[0] & SL_TYPE_COMPRESSED_TCP) { proto = PPP_VJC_COMP; cp[0] &= ~SL_TYPE_COMPRESSED_TCP; } else { proto = PPP_VJC_UNCOMP; cp[0] = skb->data[2]; } kfree_skb(skb); skb = new_skb; cp = skb_put(skb, len + 2); cp[0] = 0; cp[1] = proto; } break; case PPP_CCP: /* peek at outbound CCP frames */ ppp_ccp_peek(ppp, skb, 0); break; } /* try to do packet compression */ if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0 && proto != PPP_LCP && proto != PPP_CCP) { if (!(ppp->flags & SC_CCP_UP) && (ppp->flags & SC_MUST_COMP)) { if (net_ratelimit()) printk(KERN_ERR "ppp: compression required but down - pkt dropped.\n"); goto drop; } skb = pad_compress_skb(ppp, skb); if (!skb) goto drop; } /* * If we are waiting for traffic (demand dialling), * queue it up for pppd to receive. */ if (ppp->flags & SC_LOOP_TRAFFIC) { if (ppp->file.rq.qlen > PPP_MAX_RQLEN) goto drop; skb_queue_tail(&ppp->file.rq, skb); wake_up_interruptible(&ppp->file.rwait); return; } ppp->xmit_pending = skb; ppp_push(ppp); return; drop: if (skb) kfree_skb(skb); ++ppp->stats.tx_errors; } /* * Try to send the frame in xmit_pending. * The caller should have the xmit path locked. */ static void ppp_push(struct ppp *ppp) { struct list_head *list; struct channel *pch; struct sk_buff *skb = ppp->xmit_pending; if (skb == 0) return; list = &ppp->channels; if (list_empty(list)) { /* nowhere to send the packet, just drop it */ ppp->xmit_pending = NULL; kfree_skb(skb); return; } if ((ppp->flags & SC_MULTILINK) == 0) { /* not doing multilink: send it down the first channel */ list = list->next; pch = list_entry(list, struct channel, clist); spin_lock_bh(&pch->downl); if (pch->chan) { if (pch->chan->ops->start_xmit(pch->chan, skb)) ppp->xmit_pending = NULL; } else { /* channel got unregistered */ kfree_skb(skb); ppp->xmit_pending = NULL; } spin_unlock_bh(&pch->downl); return; } #ifdef CONFIG_PPP_MULTILINK /* Multilink: fragment the packet over as many links as can take the packet at the moment. */ if (!ppp_mp_explode(ppp, skb)) return; #endif /* CONFIG_PPP_MULTILINK */ ppp->xmit_pending = NULL; kfree_skb(skb); } #ifdef CONFIG_PPP_MULTILINK /* * Divide a packet to be transmitted into fragments and * send them out the individual links. */ static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb) { int len, fragsize; int i, bits, hdrlen, mtu; int flen; int navail, nfree; int nbigger; unsigned char *p, *q; struct list_head *list; struct channel *pch; struct sk_buff *frag; struct ppp_channel *chan; nfree = 0; /* # channels which have no packet already queued */ navail = 0; /* total # of usable channels (not deregistered) */ hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN; i = 0; list_for_each_entry(pch, &ppp->channels, clist) { navail += pch->avail = (pch->chan != NULL); if (pch->avail) { if (skb_queue_empty(&pch->file.xq) || !pch->had_frag) { pch->avail = 2; ++nfree; } if (!pch->had_frag && i < ppp->nxchan) ppp->nxchan = i; } ++i; } /* * Don't start sending this packet unless at least half of * the channels are free. This gives much better TCP * performance if we have a lot of channels. */ if (nfree == 0 || nfree < navail / 2) return 0; /* can't take now, leave it in xmit_pending */ /* Do protocol field compression (XXX this should be optional) */ p = skb->data; len = skb->len; if (*p == 0) { ++p; --len; } /* * Decide on fragment size. * We create a fragment for each free channel regardless of * how small they are (i.e. even 0 length) in order to minimize * the time that it will take to detect when a channel drops * a fragment. */ fragsize = len; if (nfree > 1) fragsize = ROUNDUP(fragsize, nfree); /* nbigger channels get fragsize bytes, the rest get fragsize-1, except if nbigger==0, then they all get fragsize. */ nbigger = len % nfree; /* skip to the channel after the one we last used and start at that one */ list = &ppp->channels; for (i = 0; i < ppp->nxchan; ++i) { list = list->next; if (list == &ppp->channels) { i = 0; break; } } /* create a fragment for each channel */ bits = B; while (nfree > 0 || len > 0) { list = list->next; if (list == &ppp->channels) { i = 0; continue; } pch = list_entry(list, struct channel, clist); ++i; if (!pch->avail) continue; /* * Skip this channel if it has a fragment pending already and * we haven't given a fragment to all of the free channels. */ if (pch->avail == 1) { if (nfree > 0) continue; } else { --nfree; pch->avail = 1; } /* check the channel's mtu and whether it is still attached. */ spin_lock_bh(&pch->downl); if (pch->chan == NULL) { /* can't use this channel, it's being deregistered */ spin_unlock_bh(&pch->downl); pch->avail = 0; if (--navail == 0) break; continue; } /* * Create a fragment for this channel of * min(max(mtu+2-hdrlen, 4), fragsize, len) bytes. * If mtu+2-hdrlen < 4, that is a ridiculously small * MTU, so we use mtu = 2 + hdrlen. */ if (fragsize > len) fragsize = len; flen = fragsize; mtu = pch->chan->mtu + 2 - hdrlen; if (mtu < 4) mtu = 4; if (flen > mtu) flen = mtu; if (flen == len && nfree == 0) bits |= E; frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC); if (frag == 0) goto noskb; q = skb_put(frag, flen + hdrlen); /* make the MP header */ q[0] = PPP_MP >> 8; q[1] = PPP_MP; if (ppp->flags & SC_MP_XSHORTSEQ) { q[2] = bits + ((ppp->nxseq >> 8) & 0xf); q[3] = ppp->nxseq; } else { q[2] = bits; q[3] = ppp->nxseq >> 16; q[4] = ppp->nxseq >> 8; q[5] = ppp->nxseq; } /* * Copy the data in. * Unfortunately there is a bug in older versions of * the Linux PPP multilink reconstruction code where it * drops 0-length fragments. Therefore we make sure the * fragment has at least one byte of data. Any bytes * we add in this situation will end up as padding on the * end of the reconstructed packet. */ if (flen == 0) *skb_put(frag, 1) = 0; else memcpy(q + hdrlen, p, flen); /* try to send it down the channel */ chan = pch->chan; if (!skb_queue_empty(&pch->file.xq) || !chan->ops->start_xmit(chan, frag)) skb_queue_tail(&pch->file.xq, frag); pch->had_frag = 1; p += flen; len -= flen; ++ppp->nxseq; bits = 0; spin_unlock_bh(&pch->downl); if (--nbigger == 0 && fragsize > 0) --fragsize; } ppp->nxchan = i; return 1; noskb: spin_unlock_bh(&pch->downl); if (ppp->debug & 1) printk(KERN_ERR "PPP: no memory (fragment)\n"); ++ppp->stats.tx_errors; ++ppp->nxseq; return 1; /* abandon the frame */ } #endif /* CONFIG_PPP_MULTILINK */ /* * Try to send data out on a channel. */ static void ppp_channel_push(struct channel *pch) { struct sk_buff *skb; struct ppp *ppp; spin_lock_bh(&pch->downl); if (pch->chan != 0) { while (!skb_queue_empty(&pch->file.xq)) { skb = skb_dequeue(&pch->file.xq); if (!pch->chan->ops->start_xmit(pch->chan, skb)) { /* put the packet back and try again later */ skb_queue_head(&pch->file.xq, skb); break; } } } else { /* channel got deregistered */ skb_queue_purge(&pch->file.xq); } spin_unlock_bh(&pch->downl); /* see if there is anything from the attached unit to be sent */ if (skb_queue_empty(&pch->file.xq)) { read_lock_bh(&pch->upl); ppp = pch->ppp; if (ppp != 0) ppp_xmit_process(ppp); read_unlock_bh(&pch->upl); } } /* * Receive-side routines. */ /* misuse a few fields of the skb for MP reconstruction */ #define sequence priority #define BEbits cb[0] static inline void ppp_do_recv(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) { ppp_recv_lock(ppp); /* ppp->dev == 0 means interface is closing down */ if (ppp->dev != 0) ppp_receive_frame(ppp, skb, pch); else kfree_skb(skb); ppp_recv_unlock(ppp); } void ppp_input(struct ppp_channel *chan, struct sk_buff *skb) { struct channel *pch = chan->ppp; int proto; if (pch == 0 || skb->len == 0) { kfree_skb(skb); return; } proto = PPP_PROTO(skb); read_lock_bh(&pch->upl); if (pch->ppp == 0 || proto >= 0xc000 || proto == PPP_CCPFRAG) { /* put it on the channel queue */ skb_queue_tail(&pch->file.rq, skb); /* drop old frames if queue too long */ while (pch->file.rq.qlen > PPP_MAX_RQLEN && (skb = skb_dequeue(&pch->file.rq)) != 0) kfree_skb(skb); wake_up_interruptible(&pch->file.rwait); } else { ppp_do_recv(pch->ppp, skb, pch); } read_unlock_bh(&pch->upl); } /* Put a 0-length skb in the receive queue as an error indication */ void ppp_input_error(struct ppp_channel *chan, int code) { struct channel *pch = chan->ppp; struct sk_buff *skb; if (pch == 0) return; read_lock_bh(&pch->upl); if (pch->ppp != 0) { skb = alloc_skb(0, GFP_ATOMIC); if (skb != 0) { skb->len = 0; /* probably unnecessary */ skb->cb[0] = code; ppp_do_recv(pch->ppp, skb, pch); } } read_unlock_bh(&pch->upl); } /* * We come in here to process a received frame. * The receive side of the ppp unit is locked. */ static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) { if (skb->len >= 2) { #ifdef CONFIG_PPP_MULTILINK /* XXX do channel-level decompression here */ if (PPP_PROTO(skb) == PPP_MP) ppp_receive_mp_frame(ppp, skb, pch); else #endif /* CONFIG_PPP_MULTILINK */ ppp_receive_nonmp_frame(ppp, skb); return; } if (skb->len > 0) /* note: a 0-length skb is used as an error indication */ ++ppp->stats.rx_length_errors; kfree_skb(skb); ppp_receive_error(ppp); } static void ppp_receive_error(struct ppp *ppp) { ++ppp->stats.rx_errors; if (ppp->vj != 0) slhc_toss(ppp->vj); } static void ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb) { struct sk_buff *ns; int proto, len, npi; /* * Decompress the frame, if compressed. * Note that some decompressors need to see uncompressed frames * that come in as well as compressed frames. */ if (ppp->rc_state != 0 && (ppp->rstate & SC_DECOMP_RUN) && (ppp->rstate & (SC_DC_FERROR | SC_DC_ERROR)) == 0) skb = ppp_decompress_frame(ppp, skb); if (ppp->flags & SC_MUST_COMP && ppp->rstate & SC_DC_FERROR) goto err; proto = PPP_PROTO(skb); switch (proto) { case PPP_VJC_COMP: /* decompress VJ compressed packets */ if (ppp->vj == 0 || (ppp->flags & SC_REJ_COMP_TCP)) goto err; if (skb_tailroom(skb) < 124) { /* copy to a new sk_buff with more tailroom */ ns = dev_alloc_skb(skb->len + 128); if (ns == 0) { printk(KERN_ERR"PPP: no memory (VJ decomp)\n"); goto err; } skb_reserve(ns, 2); skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len); kfree_skb(skb); skb = ns; } else skb->ip_summed = CHECKSUM_NONE; len = slhc_uncompress(ppp->vj, skb->data + 2, skb->len - 2); if (len <= 0) { printk(KERN_DEBUG "PPP: VJ decompression error\n"); goto err; } len += 2; if (len > skb->len) skb_put(skb, len - skb->len); else if (len < skb->len) skb_trim(skb, len); proto = PPP_IP; break; case PPP_VJC_UNCOMP: if (ppp->vj == 0 || (ppp->flags & SC_REJ_COMP_TCP)) goto err; /* Until we fix the decompressor need to make sure * data portion is linear. */ if (!pskb_may_pull(skb, skb->len)) goto err; if (slhc_remember(ppp->vj, skb->data + 2, skb->len - 2) <= 0) { printk(KERN_ERR "PPP: VJ uncompressed error\n"); goto err; } proto = PPP_IP; break; case PPP_CCP: ppp_ccp_peek(ppp, skb, 1); break; } ++ppp->stats.rx_packets; ppp->stats.rx_bytes += skb->len - 2; npi = proto_to_npindex(proto); if (npi < 0) { /* control or unknown frame - pass it to pppd */ skb_queue_tail(&ppp->file.rq, skb); /* limit queue length by dropping old frames */ while (ppp->file.rq.qlen > PPP_MAX_RQLEN && (skb = skb_dequeue(&ppp->file.rq)) != 0) kfree_skb(skb); /* wake up any process polling or blocking on read */ wake_up_interruptible(&ppp->file.rwait); } else { /* network protocol frame - give it to the kernel */ #ifdef CONFIG_PPP_FILTER /* check if the packet passes the pass and active filters */ /* the filter instructions are constructed assuming a four-byte PPP header on each packet */ *skb_push(skb, 2) = 0; if (ppp->pass_filter && sk_run_filter(skb, ppp->pass_filter, ppp->pass_len) == 0) { if (ppp->debug & 1) printk(KERN_DEBUG "PPP: inbound frame not passed\n"); kfree_skb(skb); return; } if (!(ppp->active_filter && sk_run_filter(skb, ppp->active_filter, ppp->active_len) == 0)) ppp->last_recv = jiffies; skb_pull(skb, 2); #else ppp->last_recv = jiffies; #endif /* CONFIG_PPP_FILTER */ if ((ppp->dev->flags & IFF_UP) == 0 || ppp->npmode[npi] != NPMODE_PASS) { kfree_skb(skb); } else { /* chop off protocol */ skb_pull_rcsum(skb, 2); skb->dev = ppp->dev; skb->protocol = htons(npindex_to_ethertype[npi]); skb->mac.raw = skb->data; netif_rx(skb); ppp->dev->last_rx = jiffies; } } return; err: kfree_skb(skb); ppp_receive_error(ppp); } static struct sk_buff * ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb) { int proto = PPP_PROTO(skb); struct sk_buff *ns; int len; /* Until we fix all the decompressor's need to make sure * data portion is linear. */ if (!pskb_may_pull(skb, skb->len)) goto err; if (proto == PPP_COMP) { ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN); if (ns == 0) { printk(KERN_ERR "ppp_decompress_frame: no memory\n"); goto err; } /* the decompressor still expects the A/C bytes in the hdr */ len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2, skb->len + 2, ns->data, ppp->mru + PPP_HDRLEN); if (len < 0) { /* Pass the compressed frame to pppd as an error indication. */ if (len == DECOMP_FATALERROR) ppp->rstate |= SC_DC_FERROR; kfree_skb(ns); goto err; } kfree_skb(skb); skb = ns; skb_put(skb, len); skb_pull(skb, 2); /* pull off the A/C bytes */ } else { /* Uncompressed frame - pass to decompressor so it can update its dictionary if necessary. */ if (ppp->rcomp->incomp) ppp->rcomp->incomp(ppp->rc_state, skb->data - 2, skb->len + 2); } return skb; err: ppp->rstate |= SC_DC_ERROR; ppp_receive_error(ppp); return skb; } #ifdef CONFIG_PPP_MULTILINK /* * Receive a multilink frame. * We put it on the reconstruction queue and then pull off * as many completed frames as we can. */ static void ppp_receive_mp_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch) { u32 mask, seq; struct channel *ch; int mphdrlen = (ppp->flags & SC_MP_SHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN; if (!pskb_may_pull(skb, mphdrlen) || ppp->mrru == 0) goto err; /* no good, throw it away */ /* Decode sequence number and begin/end bits */ if (ppp->flags & SC_MP_SHORTSEQ) { seq = ((skb->data[2] & 0x0f) << 8) | skb->data[3]; mask = 0xfff; } else { seq = (skb->data[3] << 16) | (skb->data[4] << 8)| skb->data[5]; mask = 0xffffff; } skb->BEbits = skb->data[2]; skb_pull(skb, mphdrlen); /* pull off PPP and MP headers */ /* * Do protocol ID decompression on the first fragment of each packet. */ if ((skb->BEbits & B) && (skb->data[0] & 1)) *skb_push(skb, 1) = 0; /* * Expand sequence number to 32 bits, making it as close * as possible to ppp->minseq. */ seq |= ppp->minseq & ~mask; if ((int)(ppp->minseq - seq) > (int)(mask >> 1)) seq += mask + 1; else if ((int)(seq - ppp->minseq) > (int)(mask >> 1)) seq -= mask + 1; /* should never happen */ skb->sequence = seq; pch->lastseq = seq; /* * If this packet comes before the next one we were expecting, * drop it. */ if (seq_before(seq, ppp->nextseq)) { kfree_skb(skb); ++ppp->stats.rx_dropped; ppp_receive_error(ppp); return; } /* * Reevaluate minseq, the minimum over all channels of the * last sequence number received on each channel. Because of * the increasing sequence number rule, we know that any fragment * before `minseq' which hasn't arrived is never going to arrive. * The list of channels can't change because we have the receive * side of the ppp unit locked. */ list_for_each_entry(ch, &ppp->channels, clist) { if (seq_before(ch->lastseq, seq)) seq = ch->lastseq; } if (seq_before(ppp->minseq, seq)) ppp->minseq = seq; /* Put the fragment on the reconstruction queue */ ppp_mp_insert(ppp, skb); /* If the queue is getting long, don't wait any longer for packets before the start of the queue. */ if (skb_queue_len(&ppp->mrq) >= PPP_MP_MAX_QLEN && seq_before(ppp->minseq, ppp->mrq.next->sequence)) ppp->minseq = ppp->mrq.next->sequence; /* Pull completed packets off the queue and receive them. */ while ((skb = ppp_mp_reconstruct(ppp)) != 0) ppp_receive_nonmp_frame(ppp, skb); return; err: kfree_skb(skb); ppp_receive_error(ppp); } /* * Insert a fragment on the MP reconstruction queue. * The queue is ordered by increasing sequence number. */ static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb) { struct sk_buff *p; struct sk_buff_head *list = &ppp->mrq; u32 seq = skb->sequence; /* N.B. we don't need to lock the list lock because we have the ppp unit receive-side lock. */ for (p = list->next; p != (struct sk_buff *)list; p = p->next) if (seq_before(seq, p->sequence)) break; __skb_insert(skb, p->prev, p, list); } /* * Reconstruct a packet from the MP fragment queue. * We go through increasing sequence numbers until we find a * complete packet, or we get to the sequence number for a fragment * which hasn't arrived but might still do so. */ struct sk_buff * ppp_mp_reconstruct(struct ppp *ppp) { u32 seq = ppp->nextseq; u32 minseq = ppp->minseq; struct sk_buff_head *list = &ppp->mrq; struct sk_buff *p, *next; struct sk_buff *head, *tail; struct sk_buff *skb = NULL; int lost = 0, len = 0; if (ppp->mrru == 0) /* do nothing until mrru is set */ return NULL; head = list->next; tail = NULL; for (p = head; p != (struct sk_buff *) list; p = next) { next = p->next; if (seq_before(p->sequence, seq)) { /* this can't happen, anyway ignore the skb */ printk(KERN_ERR "ppp_mp_reconstruct bad seq %u < %u\n", p->sequence, seq); head = next; continue; } if (p->sequence != seq) { /* Fragment `seq' is missing. If it is after minseq, it might arrive later, so stop here. */ if (seq_after(seq, minseq)) break; /* Fragment `seq' is lost, keep going. */ lost = 1; seq = seq_before(minseq, p->sequence)? minseq + 1: p->sequence; next = p; continue; } /* * At this point we know that all the fragments from * ppp->nextseq to seq are either present or lost. * Also, there are no complete packets in the queue * that have no missing fragments and end before this * fragment. */ /* B bit set indicates this fragment starts a packet */ if (p->BEbits & B) { head = p; lost = 0; len = 0; } len += p->len; /* Got a complete packet yet? */ if (lost == 0 && (p->BEbits & E) && (head->BEbits & B)) { if (len > ppp->mrru + 2) { ++ppp->stats.rx_length_errors; printk(KERN_DEBUG "PPP: reconstructed packet" " is too long (%d)\n", len); } else if (p == head) { /* fragment is complete packet - reuse skb */ tail = p; skb = skb_get(p); break; } else if ((skb = dev_alloc_skb(len)) == NULL) { ++ppp->stats.rx_missed_errors; printk(KERN_DEBUG "PPP: no memory for " "reconstructed packet"); } else { tail = p; break; } ppp->nextseq = seq + 1; } /* * If this is the ending fragment of a packet, * and we haven't found a complete valid packet yet, * we can discard up to and including this fragment. */ if (p->BEbits & E) head = next; ++seq; } /* If we have a complete packet, copy it all into one skb. */ if (tail != NULL) { /* If we have discarded any fragments, signal a receive error. */ if (head->sequence != ppp->nextseq) { if (ppp->debug & 1) printk(KERN_DEBUG " missed pkts %u..%u\n", ppp->nextseq, head->sequence-1); ++ppp->stats.rx_dropped; ppp_receive_error(ppp); } if (head != tail) /* copy to a single skb */ for (p = head; p != tail->next; p = p->next) skb_copy_bits(p, 0, skb_put(skb, p->len), p->len); ppp->nextseq = tail->sequence + 1; head = tail->next; } /* Discard all the skbuffs that we have copied the data out of or that we can't use. */ while ((p = list->next) != head) { __skb_unlink(p, list); kfree_skb(p); } return skb; } #endif /* CONFIG_PPP_MULTILINK */ /* * Channel interface. */ /* * Create a new, unattached ppp channel. */ int ppp_register_channel(struct ppp_channel *chan) { struct channel *pch; pch = kzalloc(sizeof(struct channel), GFP_KERNEL); if (pch == 0) return -ENOMEM; pch->ppp = NULL; pch->chan = chan; chan->ppp = pch; init_ppp_file(&pch->file, CHANNEL); pch->file.hdrlen = chan->hdrlen; #ifdef CONFIG_PPP_MULTILINK pch->lastseq = -1; #endif /* CONFIG_PPP_MULTILINK */ init_rwsem(&pch->chan_sem); spin_lock_init(&pch->downl); rwlock_init(&pch->upl); spin_lock_bh(&all_channels_lock); pch->file.index = ++last_channel_index; list_add(&pch->list, &new_channels); atomic_inc(&channel_count); spin_unlock_bh(&all_channels_lock); return 0; } /* * Return the index of a channel. */ int ppp_channel_index(struct ppp_channel *chan) { struct channel *pch = chan->ppp; if (pch != 0) return pch->file.index; return -1; } /* * Return the PPP unit number to which a channel is connected. */ int ppp_unit_number(struct ppp_channel *chan) { struct channel *pch = chan->ppp; int unit = -1; if (pch != 0) { read_lock_bh(&pch->upl); if (pch->ppp != 0) unit = pch->ppp->file.index; read_unlock_bh(&pch->upl); } return unit; } /* * Disconnect a channel from the generic layer. * This must be called in process context. */ void ppp_unregister_channel(struct ppp_channel *chan) { struct channel *pch = chan->ppp; if (pch == 0) return; /* should never happen */ chan->ppp = NULL; /* * This ensures that we have returned from any calls into the * the channel's start_xmit or ioctl routine before we proceed. */ down_write(&pch->chan_sem); spin_lock_bh(&pch->downl); pch->chan = NULL; spin_unlock_bh(&pch->downl); up_write(&pch->chan_sem); ppp_disconnect_channel(pch); spin_lock_bh(&all_channels_lock); list_del(&pch->list); spin_unlock_bh(&all_channels_lock); pch->file.dead = 1; wake_up_interruptible(&pch->file.rwait); if (atomic_dec_and_test(&pch->file.refcnt)) ppp_destroy_channel(pch); } /* * Callback from a channel when it can accept more to transmit. * This should be called at BH/softirq level, not interrupt level. */ void ppp_output_wakeup(struct ppp_channel *chan) { struct channel *pch = chan->ppp; if (pch == 0) return; ppp_channel_push(pch); } /* * Compression control. */ /* Process the PPPIOCSCOMPRESS ioctl. */ static int ppp_set_compress(struct ppp *ppp, unsigned long arg) { int err; struct compressor *cp, *ocomp; struct ppp_option_data data; void *state, *ostate; unsigned char ccp_option[CCP_MAX_OPTION_LENGTH]; err = -EFAULT; if (copy_from_user(&data, (void __user *) arg, sizeof(data)) || (data.length <= CCP_MAX_OPTION_LENGTH && copy_from_user(ccp_option, (void __user *) data.ptr, data.length))) goto out; err = -EINVAL; if (data.length > CCP_MAX_OPTION_LENGTH || ccp_option[1] < 2 || ccp_option[1] > data.length) goto out; cp = find_compressor(ccp_option[0]); #ifdef CONFIG_KMOD if (cp == 0) { request_module("ppp-compress-%d", ccp_option[0]); cp = find_compressor(ccp_option[0]); } #endif /* CONFIG_KMOD */ if (cp == 0) goto out; err = -ENOBUFS; if (data.transmit) { state = cp->comp_alloc(ccp_option, data.length); if (state != 0) { ppp_xmit_lock(ppp); ppp->xstate &= ~SC_COMP_RUN; ocomp = ppp->xcomp; ostate = ppp->xc_state; ppp->xcomp = cp; ppp->xc_state = state; ppp_xmit_unlock(ppp); if (ostate != 0) { ocomp->comp_free(ostate); module_put(ocomp->owner); } err = 0; } else module_put(cp->owner); } else { state = cp->decomp_alloc(ccp_option, data.length); if (state != 0) { ppp_recv_lock(ppp); ppp->rstate &= ~SC_DECOMP_RUN; ocomp = ppp->rcomp; ostate = ppp->rc_state; ppp->rcomp = cp; ppp->rc_state = state; ppp_recv_unlock(ppp); if (ostate != 0) { ocomp->decomp_free(ostate); module_put(ocomp->owner); } err = 0; } else module_put(cp->owner); } out: return err; } /* * Look at a CCP packet and update our state accordingly. * We assume the caller has the xmit or recv path locked. */ static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound) { unsigned char *dp; int len; if (!pskb_may_pull(skb, CCP_HDRLEN + 2)) return; /* no header */ dp = skb->data + 2; switch (CCP_CODE(dp)) { case CCP_CONFREQ: /* A ConfReq starts negotiation of compression * in one direction of transmission, * and hence brings it down...but which way? * * Remember: * A ConfReq indicates what the sender would like to receive */ if(inbound) /* He is proposing what I should send */ ppp->xstate &= ~SC_COMP_RUN; else /* I am proposing to what he should send */ ppp->rstate &= ~SC_DECOMP_RUN; break; case CCP_TERMREQ: case CCP_TERMACK: /* * CCP is going down, both directions of transmission */ ppp->rstate &= ~SC_DECOMP_RUN; ppp->xstate &= ~SC_COMP_RUN; break; case CCP_CONFACK: if ((ppp->flags & (SC_CCP_OPEN | SC_CCP_UP)) != SC_CCP_OPEN) break; len = CCP_LENGTH(dp); if (!pskb_may_pull(skb, len + 2)) return; /* too short */ dp += CCP_HDRLEN; len -= CCP_HDRLEN; if (len < CCP_OPT_MINLEN || len < CCP_OPT_LENGTH(dp)) break; if (inbound) { /* we will start receiving compressed packets */ if (ppp->rc_state == 0) break; if (ppp->rcomp->decomp_init(ppp->rc_state, dp, len, ppp->file.index, 0, ppp->mru, ppp->debug)) { ppp->rstate |= SC_DECOMP_RUN; ppp->rstate &= ~(SC_DC_ERROR | SC_DC_FERROR); } } else { /* we will soon start sending compressed packets */ if (ppp->xc_state == 0) break; if (ppp->xcomp->comp_init(ppp->xc_state, dp, len, ppp->file.index, 0, ppp->debug)) ppp->xstate |= SC_COMP_RUN; } break; case CCP_RESETACK: /* reset the [de]compressor */ if ((ppp->flags & SC_CCP_UP) == 0) break; if (inbound) { if (ppp->rc_state && (ppp->rstate & SC_DECOMP_RUN)) { ppp->rcomp->decomp_reset(ppp->rc_state); ppp->rstate &= ~SC_DC_ERROR; } } else { if (ppp->xc_state && (ppp->xstate & SC_COMP_RUN)) ppp->xcomp->comp_reset(ppp->xc_state); } break; } } /* Free up compression resources. */ static void ppp_ccp_closed(struct ppp *ppp) { void *xstate, *rstate; struct compressor *xcomp, *rcomp; ppp_lock(ppp); ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP); ppp->xstate = 0; xcomp = ppp->xcomp; xstate = ppp->xc_state; ppp->xc_state = NULL; ppp->rstate = 0; rcomp = ppp->rcomp; rstate = ppp->rc_state; ppp->rc_state = NULL; ppp_unlock(ppp); if (xstate) { xcomp->comp_free(xstate); module_put(xcomp->owner); } if (rstate) { rcomp->decomp_free(rstate); module_put(rcomp->owner); } } /* List of compressors. */ static LIST_HEAD(compressor_list); static DEFINE_SPINLOCK(compressor_list_lock); struct compressor_entry { struct list_head list; struct compressor *comp; }; static struct compressor_entry * find_comp_entry(int proto) { struct compressor_entry *ce; list_for_each_entry(ce, &compressor_list, list) { if (ce->comp->compress_proto == proto) return ce; } return NULL; } /* Register a compressor */ int ppp_register_compressor(struct compressor *cp) { struct compressor_entry *ce; int ret; spin_lock(&compressor_list_lock); ret = -EEXIST; if (find_comp_entry(cp->compress_proto) != 0) goto out; ret = -ENOMEM; ce = kmalloc(sizeof(struct compressor_entry), GFP_ATOMIC); if (ce == 0) goto out; ret = 0; ce->comp = cp; list_add(&ce->list, &compressor_list); out: spin_unlock(&compressor_list_lock); return ret; } /* Unregister a compressor */ void ppp_unregister_compressor(struct compressor *cp) { struct compressor_entry *ce; spin_lock(&compressor_list_lock); ce = find_comp_entry(cp->compress_proto); if (ce != 0 && ce->comp == cp) { list_del(&ce->list); kfree(ce); } spin_unlock(&compressor_list_lock); } /* Find a compressor. */ static struct compressor * find_compressor(int type) { struct compressor_entry *ce; struct compressor *cp = NULL; spin_lock(&compressor_list_lock); ce = find_comp_entry(type); if (ce != 0) { cp = ce->comp; if (!try_module_get(cp->owner)) cp = NULL; } spin_unlock(&compressor_list_lock); return cp; } /* * Miscelleneous stuff. */ static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st) { struct slcompress *vj = ppp->vj; memset(st, 0, sizeof(*st)); st->p.ppp_ipackets = ppp->stats.rx_packets; st->p.ppp_ierrors = ppp->stats.rx_errors; st->p.ppp_ibytes = ppp->stats.rx_bytes; st->p.ppp_opackets = ppp->stats.tx_packets; st->p.ppp_oerrors = ppp->stats.tx_errors; st->p.ppp_obytes = ppp->stats.tx_bytes; if (vj == 0) return; st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed; st->vj.vjs_compressed = vj->sls_o_compressed; st->vj.vjs_searches = vj->sls_o_searches; st->vj.vjs_misses = vj->sls_o_misses; st->vj.vjs_errorin = vj->sls_i_error; st->vj.vjs_tossed = vj->sls_i_tossed; st->vj.vjs_uncompressedin = vj->sls_i_uncompressed; st->vj.vjs_compressedin = vj->sls_i_compressed; } /* * Stuff for handling the lists of ppp units and channels * and for initialization. */ /* * Create a new ppp interface unit. Fails if it can't allocate memory * or if there is already a unit with the requested number. * unit == -1 means allocate a new number. */ static struct ppp * ppp_create_interface(int unit, int *retp) { struct ppp *ppp; struct net_device *dev = NULL; int ret = -ENOMEM; int i; ppp = kzalloc(sizeof(struct ppp), GFP_KERNEL); if (!ppp) goto out; dev = alloc_netdev(0, "", ppp_setup); if (!dev) goto out1; ppp->mru = PPP_MRU; init_ppp_file(&ppp->file, INTERFACE); ppp->file.hdrlen = PPP_HDRLEN - 2; /* don't count proto bytes */ for (i = 0; i < NUM_NP; ++i) ppp->npmode[i] = NPMODE_PASS; INIT_LIST_HEAD(&ppp->channels); spin_lock_init(&ppp->rlock); spin_lock_init(&ppp->wlock); #ifdef CONFIG_PPP_MULTILINK ppp->minseq = -1; skb_queue_head_init(&ppp->mrq); #endif /* CONFIG_PPP_MULTILINK */ ppp->dev = dev; dev->priv = ppp; dev->hard_start_xmit = ppp_start_xmit; dev->get_stats = ppp_net_stats; dev->do_ioctl = ppp_net_ioctl; ret = -EEXIST; mutex_lock(&all_ppp_mutex); if (unit < 0) unit = cardmap_find_first_free(all_ppp_units); else if (cardmap_get(all_ppp_units, unit) != NULL) goto out2; /* unit already exists */ /* Initialize the new ppp unit */ ppp->file.index = unit; sprintf(dev->name, "ppp%d", unit); ret = register_netdev(dev); if (ret != 0) { printk(KERN_ERR "PPP: couldn't register device %s (%d)\n", dev->name, ret); goto out2; } atomic_inc(&ppp_unit_count); ret = cardmap_set(&all_ppp_units, unit, ppp); if (ret != 0) goto out3; mutex_unlock(&all_ppp_mutex); *retp = 0; return ppp; out3: atomic_dec(&ppp_unit_count); out2: mutex_unlock(&all_ppp_mutex); free_netdev(dev); out1: kfree(ppp); out: *retp = ret; return NULL; } /* * Initialize a ppp_file structure. */ static void init_ppp_file(struct ppp_file *pf, int kind) { pf->kind = kind; skb_queue_head_init(&pf->xq); skb_queue_head_init(&pf->rq); atomic_set(&pf->refcnt, 1); init_waitqueue_head(&pf->rwait); } /* * Take down a ppp interface unit - called when the owning file * (the one that created the unit) is closed or detached. */ static void ppp_shutdown_interface(struct ppp *ppp) { struct net_device *dev; mutex_lock(&all_ppp_mutex); ppp_lock(ppp); dev = ppp->dev; ppp->dev = NULL; ppp_unlock(ppp); /* This will call dev_close() for us. */ if (dev) { unregister_netdev(dev); free_netdev(dev); } cardmap_set(&all_ppp_units, ppp->file.index, NULL); ppp->file.dead = 1; ppp->owner = NULL; wake_up_interruptible(&ppp->file.rwait); mutex_unlock(&all_ppp_mutex); } /* * Free the memory used by a ppp unit. This is only called once * there are no channels connected to the unit and no file structs * that reference the unit. */ static void ppp_destroy_interface(struct ppp *ppp) { atomic_dec(&ppp_unit_count); if (!ppp->file.dead || ppp->n_channels) { /* "can't happen" */ printk(KERN_ERR "ppp: destroying ppp struct %p but dead=%d " "n_channels=%d !\n", ppp, ppp->file.dead, ppp->n_channels); return; } ppp_ccp_closed(ppp); if (ppp->vj) { slhc_free(ppp->vj); ppp->vj = NULL; } skb_queue_purge(&ppp->file.xq); skb_queue_purge(&ppp->file.rq); #ifdef CONFIG_PPP_MULTILINK skb_queue_purge(&ppp->mrq); #endif /* CONFIG_PPP_MULTILINK */ #ifdef CONFIG_PPP_FILTER kfree(ppp->pass_filter); ppp->pass_filter = NULL; kfree(ppp->active_filter); ppp->active_filter = NULL; #endif /* CONFIG_PPP_FILTER */ kfree(ppp); } /* * Locate an existing ppp unit. * The caller should have locked the all_ppp_mutex. */ static struct ppp * ppp_find_unit(int unit) { return cardmap_get(all_ppp_units, unit); } /* * Locate an existing ppp channel. * The caller should have locked the all_channels_lock. * First we look in the new_channels list, then in the * all_channels list. If found in the new_channels list, * we move it to the all_channels list. This is for speed * when we have a lot of channels in use. */ static struct channel * ppp_find_channel(int unit) { struct channel *pch; list_for_each_entry(pch, &new_channels, list) { if (pch->file.index == unit) { list_move(&pch->list, &all_channels); return pch; } } list_for_each_entry(pch, &all_channels, list) { if (pch->file.index == unit) return pch; } return NULL; } /* * Connect a PPP channel to a PPP interface unit. */ static int ppp_connect_channel(struct channel *pch, int unit) { struct ppp *ppp; int ret = -ENXIO; int hdrlen; mutex_lock(&all_ppp_mutex); ppp = ppp_find_unit(unit); if (ppp == 0) goto out; write_lock_bh(&pch->upl); ret = -EINVAL; if (pch->ppp != 0) goto outl; ppp_lock(ppp); if (pch->file.hdrlen > ppp->file.hdrlen) ppp->file.hdrlen = pch->file.hdrlen; hdrlen = pch->file.hdrlen + 2; /* for protocol bytes */ if (ppp->dev && hdrlen > ppp->dev->hard_header_len) ppp->dev->hard_header_len = hdrlen; list_add_tail(&pch->clist, &ppp->channels); ++ppp->n_channels; pch->ppp = ppp; atomic_inc(&ppp->file.refcnt); ppp_unlock(ppp); ret = 0; outl: write_unlock_bh(&pch->upl); out: mutex_unlock(&all_ppp_mutex); return ret; } /* * Disconnect a channel from its ppp unit. */ static int ppp_disconnect_channel(struct channel *pch) { struct ppp *ppp; int err = -EINVAL; write_lock_bh(&pch->upl); ppp = pch->ppp; pch->ppp = NULL; write_unlock_bh(&pch->upl); if (ppp != 0) { /* remove it from the ppp unit's list */ ppp_lock(ppp); list_del(&pch->clist); if (--ppp->n_channels == 0) wake_up_interruptible(&ppp->file.rwait); ppp_unlock(ppp); if (atomic_dec_and_test(&ppp->file.refcnt)) ppp_destroy_interface(ppp); err = 0; } return err; } /* * Free up the resources used by a ppp channel. */ static void ppp_destroy_channel(struct channel *pch) { atomic_dec(&channel_count); if (!pch->file.dead) { /* "can't happen" */ printk(KERN_ERR "ppp: destroying undead channel %p !\n", pch); return; } skb_queue_purge(&pch->file.xq); skb_queue_purge(&pch->file.rq); kfree(pch); } static void __exit ppp_cleanup(void) { /* should never happen */ if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count)) printk(KERN_ERR "PPP: removing module but units remain!\n"); cardmap_destroy(&all_ppp_units); if (unregister_chrdev(PPP_MAJOR, "ppp") != 0) printk(KERN_ERR "PPP: failed to unregister PPP device\n"); class_device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0)); class_destroy(ppp_class); } /* * Cardmap implementation. */ static void *cardmap_get(struct cardmap *map, unsigned int nr) { struct cardmap *p; int i; for (p = map; p != NULL; ) { if ((i = nr >> p->shift) >= CARDMAP_WIDTH) return NULL; if (p->shift == 0) return p->ptr[i]; nr &= ~(CARDMAP_MASK << p->shift); p = p->ptr[i]; } return NULL; } static int cardmap_set(struct cardmap **pmap, unsigned int nr, void *ptr) { struct cardmap *p; int i; p = *pmap; if (p == NULL || (nr >> p->shift) >= CARDMAP_WIDTH) { do { /* need a new top level */ struct cardmap *np = kzalloc(sizeof(*np), GFP_KERNEL); if (!np) goto enomem; np->ptr[0] = p; if (p != NULL) { np->shift = p->shift + CARDMAP_ORDER; p->parent = np; } else np->shift = 0; p = np; } while ((nr >> p->shift) >= CARDMAP_WIDTH); *pmap = p; } while (p->shift > 0) { i = (nr >> p->shift) & CARDMAP_MASK; if (p->ptr[i] == NULL) { struct cardmap *np = kzalloc(sizeof(*np), GFP_KERNEL); if (!np) goto enomem; np->shift = p->shift - CARDMAP_ORDER; np->parent = p; p->ptr[i] = np; } if (ptr == NULL) clear_bit(i, &p->inuse); p = p->ptr[i]; } i = nr & CARDMAP_MASK; p->ptr[i] = ptr; if (ptr != NULL) set_bit(i, &p->inuse); else clear_bit(i, &p->inuse); return 0; enomem: return -ENOMEM; } static unsigned int cardmap_find_first_free(struct cardmap *map) { struct cardmap *p; unsigned int nr = 0; int i; if ((p = map) == NULL) return 0; for (;;) { i = find_first_zero_bit(&p->inuse, CARDMAP_WIDTH); if (i >= CARDMAP_WIDTH) { if (p->parent == NULL) return CARDMAP_WIDTH << p->shift; p = p->parent; i = (nr >> p->shift) & CARDMAP_MASK; set_bit(i, &p->inuse); continue; } nr = (nr & (~CARDMAP_MASK << p->shift)) | (i << p->shift); if (p->shift == 0 || p->ptr[i] == NULL) return nr; p = p->ptr[i]; } } static void cardmap_destroy(struct cardmap **pmap) { struct cardmap *p, *np; int i; for (p = *pmap; p != NULL; p = np) { if (p->shift != 0) { for (i = 0; i < CARDMAP_WIDTH; ++i) if (p->ptr[i] != NULL) break; if (i < CARDMAP_WIDTH) { np = p->ptr[i]; p->ptr[i] = NULL; continue; } } np = p->parent; kfree(p); } *pmap = NULL; } /* Module/initialization stuff */ module_init(ppp_init); module_exit(ppp_cleanup); EXPORT_SYMBOL(ppp_register_channel); EXPORT_SYMBOL(ppp_unregister_channel); EXPORT_SYMBOL(ppp_channel_index); EXPORT_SYMBOL(ppp_unit_number); EXPORT_SYMBOL(ppp_input); EXPORT_SYMBOL(ppp_input_error); EXPORT_SYMBOL(ppp_output_wakeup); EXPORT_SYMBOL(ppp_register_compressor); EXPORT_SYMBOL(ppp_unregister_compressor); MODULE_LICENSE("GPL"); MODULE_ALIAS_CHARDEV_MAJOR(PPP_MAJOR); MODULE_ALIAS("/dev/ppp");