diff options
Diffstat (limited to 'drivers/pptp/pptp.c')
| -rw-r--r-- | drivers/pptp/pptp.c | 1272 |
1 files changed, 1272 insertions, 0 deletions
diff --git a/drivers/pptp/pptp.c b/drivers/pptp/pptp.c new file mode 100644 index 0000000..78853fc --- /dev/null +++ b/drivers/pptp/pptp.c @@ -0,0 +1,1272 @@ +/* + * Point-to-Point Tunneling Protocol for Linux + * + * Authors: Kozlov D. (xeb@mail.ru) + * + * 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. + * + */ + +#include <linux/string.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/errno.h> +#include <linux/netdevice.h> +#include <linux/net.h> +#include <linux/skbuff.h> +#include <linux/init.h> +#include <linux/ppp_channel.h> +#include <linux/ppp_defs.h> +#include "if_pppox.h" +#include <linux/if_ppp.h> +#include <linux/notifier.h> +#include <linux/file.h> +#include <linux/in.h> +#include <linux/ip.h> +#include <linux/netfilter.h> +#include <linux/netfilter_ipv4.h> +#include <linux/version.h> + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) +#include <asm/bitops.h> +#endif + +#include <net/sock.h> +#include <net/protocol.h> +#include <net/ip.h> +#include <net/icmp.h> +#include <net/route.h> + +#include <asm/uaccess.h> + +#define DEBUG +//#define CONFIG_GRE + +#if defined(CONFIG_GRE) || defined(CONFIG_GRE_MODULE) +#include "gre.h" +#endif + +#define PPTP_DRIVER_VERSION "0.8.5" + +static int log_level=0; +static int log_packets=10; + +#define MAX_CALLID 65535 +#define PPP_LCP_ECHOREQ 0x09 +#define PPP_LCP_ECHOREP 0x0A + +static DECLARE_BITMAP(callid_bitmap, MAX_CALLID + 1); +static struct pppox_sock **callid_sock; + +#define SC_RCV_BITS (SC_RCV_B7_1|SC_RCV_B7_0|SC_RCV_ODDP|SC_RCV_EVNP) + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) +#define INIT_TIMER(_timer,_routine,_data) \ +do { \ + (_timer)->function=_routine; \ + (_timer)->data=_data; \ + init_timer(_timer); \ +} while (0); + +static inline void *kzalloc(size_t size,int gfp) +{ + void *p=kmalloc(size,gfp); + memset(p,0,size); + return p; +} + +#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,4,20) +static inline void nf_reset(struct sk_buff *skb) +{ +#ifdef CONFIG_NETFILTER + nf_conntrack_put(skb->nfct); + skb->nfct=NULL; +#ifdef CONFIG_NETFILTER_DEBUG + skb->nf_debug=0; +#endif +#endif +} +#define __user +#endif + +/** + * __ffs - find first bit in word. + * @word: The word to search + * + * Undefined if no bit exists, so code should check against 0 first. + */ +static inline unsigned long __ffs(unsigned long word) +{ + int num = 0; + +#if BITS_PER_LONG == 64 + if ((word & 0xffffffff) == 0) { + num += 32; + word >>= 32; + } +#endif + if ((word & 0xffff) == 0) { + num += 16; + word >>= 16; + } + if ((word & 0xff) == 0) { + num += 8; + word >>= 8; + } + if ((word & 0xf) == 0) { + num += 4; + word >>= 4; + } + if ((word & 0x3) == 0) { + num += 2; + word >>= 2; + } + if ((word & 0x1) == 0) + num += 1; + return num; +} + +#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG) +/* + * Find the next set bit in a memory region. + */ +static unsigned long find_next_bit(const unsigned long *addr, unsigned long size, + unsigned long offset) +{ + const unsigned long *p = addr + BITOP_WORD(offset); + unsigned long result = offset & ~(BITS_PER_LONG-1); + unsigned long tmp; + + if (offset >= size) + return size; + size -= result; + offset %= BITS_PER_LONG; + if (offset) { + tmp = *(p++); + tmp &= (~0UL << offset); + if (size < BITS_PER_LONG) + goto found_first; + if (tmp) + goto found_middle; + size -= BITS_PER_LONG; + result += BITS_PER_LONG; + } + while (size & ~(BITS_PER_LONG-1)) { + if ((tmp = *(p++))) + goto found_middle; + result += BITS_PER_LONG; + size -= BITS_PER_LONG; + } + if (!size) + return result; + tmp = *p; + +found_first: + tmp &= (~0UL >> (BITS_PER_LONG - size)); + if (tmp == 0UL) /* Are any bits set? */ + return result + size; /* Nope. */ +found_middle: + return result + __ffs(tmp); +} +#endif + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) +static rwlock_t chan_lock=RW_LOCK_UNLOCKED; +#define SK_STATE(sk) (sk)->state +#else +static DEFINE_SPINLOCK(chan_lock); +#define SK_STATE(sk) (sk)->sk_state +#endif + +static int pptp_xmit(struct ppp_channel *chan, struct sk_buff *skb); +static int pptp_ppp_ioctl(struct ppp_channel *chan, unsigned int cmd, + unsigned long arg); +static int pptp_rcv_core(struct sock *sk,struct sk_buff *skb); + +static struct ppp_channel_ops pptp_chan_ops= { + .start_xmit = pptp_xmit, + .ioctl=pptp_ppp_ioctl, +}; + + +#define MISSING_WINDOW 20 +#define WRAPPED( curseq, lastseq) \ + ((((curseq) & 0xffffff00) == 0) && \ + (((lastseq) & 0xffffff00 ) == 0xffffff00)) + +/* gre header structure: -------------------------------------------- */ + +#define PPTP_GRE_PROTO 0x880B +#define PPTP_GRE_VER 0x1 + +#define PPTP_GRE_FLAG_C 0x80 +#define PPTP_GRE_FLAG_R 0x40 +#define PPTP_GRE_FLAG_K 0x20 +#define PPTP_GRE_FLAG_S 0x10 +#define PPTP_GRE_FLAG_A 0x80 + +#define PPTP_GRE_IS_C(f) ((f)&PPTP_GRE_FLAG_C) +#define PPTP_GRE_IS_R(f) ((f)&PPTP_GRE_FLAG_R) +#define PPTP_GRE_IS_K(f) ((f)&PPTP_GRE_FLAG_K) +#define PPTP_GRE_IS_S(f) ((f)&PPTP_GRE_FLAG_S) +#define PPTP_GRE_IS_A(f) ((f)&PPTP_GRE_FLAG_A) + +struct pptp_gre_header { + u8 flags; /* bitfield */ + u8 ver; /* should be PPTP_GRE_VER (enhanced GRE) */ + u16 protocol; /* should be PPTP_GRE_PROTO (ppp-encaps) */ + u16 payload_len; /* size of ppp payload, not inc. gre header */ + u16 call_id; /* peer's call_id for this session */ + u32 seq; /* sequence number. Present if S==1 */ + u32 ack; /* seq number of highest packet recieved by */ + /* sender in this session */ +} __packed; +#define PPTP_HEADER_OVERHEAD (2+sizeof(struct pptp_gre_header)) + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) +static struct pppox_sock * lookup_chan(u16 call_id, u32 s_addr) +#else +static struct pppox_sock * lookup_chan(u16 call_id, __be32 s_addr) +#endif +{ + struct pppox_sock *sock; + struct pptp_opt *opt; + +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + rcu_read_lock(); + sock = rcu_dereference(callid_sock[call_id]); +#else + read_lock(&chan_lock); + sock = callid_sock[call_id]; +#endif + if (sock) { + opt=&sock->proto.pptp; + if (opt->dst_addr.sin_addr.s_addr!=s_addr) sock=NULL; + else sock_hold(sk_pppox(sock)); + } +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + rcu_read_unlock(); +#else + read_unlock(&chan_lock); +#endif + + return sock; +} + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) +static int lookup_chan_dst(u16 call_id, u32 d_addr) +#else +static int lookup_chan_dst(u16 call_id, __be32 d_addr) +#endif +{ + struct pppox_sock *sock; + struct pptp_opt *opt; + int i; + +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + rcu_read_lock(); +#else + down(&chan_lock); +#endif + for(i = find_next_bit(callid_bitmap,MAX_CALLID,1); i < MAX_CALLID; + i = find_next_bit(callid_bitmap, MAX_CALLID, i + 1)){ +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + sock = rcu_dereference(callid_sock[i]); +#else + sock = callid_sock[i]; +#endif + if (!sock) + continue; + opt = &sock->proto.pptp; + if (opt->dst_addr.call_id == call_id && opt->dst_addr.sin_addr.s_addr == d_addr) break; + } +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + rcu_read_unlock(); +#else + up(&chan_lock); +#endif + + return i<MAX_CALLID; +} + +static int add_chan(struct pppox_sock *sock) +{ + static int call_id=0; + int res=-1; + +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + spin_lock(&chan_lock); +#else + write_lock_bh(&chan_lock); +#endif + + if (!sock->proto.pptp.src_addr.call_id) + { + call_id=find_next_zero_bit(callid_bitmap,MAX_CALLID,call_id+1); + if (call_id==MAX_CALLID) + call_id=find_next_zero_bit(callid_bitmap,MAX_CALLID,1); + sock->proto.pptp.src_addr.call_id=call_id; + } + else if (test_bit(sock->proto.pptp.src_addr.call_id,callid_bitmap)) + goto exit; + +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + rcu_assign_pointer(callid_sock[sock->proto.pptp.src_addr.call_id],sock); +#else + callid_sock[sock->proto.pptp.src_addr.call_id] = sock; +#endif + set_bit(sock->proto.pptp.src_addr.call_id,callid_bitmap); + res=0; + +exit: + #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + spin_unlock(&chan_lock); + #else + write_unlock_bh(&chan_lock); + #endif + + return res; +} + +static void del_chan(struct pppox_sock *sock) +{ +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + spin_lock(&chan_lock); +#else + write_lock_bh(&chan_lock); +#endif + clear_bit(sock->proto.pptp.src_addr.call_id,callid_bitmap); +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + rcu_assign_pointer(callid_sock[sock->proto.pptp.src_addr.call_id],NULL); + spin_unlock(&chan_lock); + synchronize_rcu(); +#else + callid_sock[sock->proto.pptp.src_addr.call_id] = NULL; + write_unlock_bh(&chan_lock); +#endif +} + +static int pptp_xmit(struct ppp_channel *chan, struct sk_buff *skb) +{ + struct sock *sk = (struct sock *) chan->private; + struct pppox_sock *po = pppox_sk(sk); + struct pptp_opt *opt=&po->proto.pptp; + struct pptp_gre_header *hdr; + unsigned int header_len=sizeof(*hdr); + int err=0; + int islcp; + int len; + unsigned char *data; + u32 seq_recv; + + + struct rtable *rt; /* Route to the other host */ + struct net_device *tdev; /* Device to other host */ + struct iphdr *iph; /* Our new IP header */ + int max_headroom; /* The extra header space needed */ + + if (SK_STATE(sk_pppox(po)) & PPPOX_DEAD) + goto tx_error; + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + { + struct rt_key key = { + .dst=opt->dst_addr.sin_addr.s_addr, + .src=opt->src_addr.sin_addr.s_addr, + .tos=RT_TOS(0), + }; + if ((err=ip_route_output_key(&rt, &key))) { + goto tx_error; + } + } +#else + { + struct flowi fl = { .oif = 0, + .nl_u = { .ip4_u = + { .daddr = opt->dst_addr.sin_addr.s_addr, + .saddr = opt->src_addr.sin_addr.s_addr, + .tos = RT_TOS(0) } }, + .proto = IPPROTO_GRE }; +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25) + if ((err=ip_route_output_key(&rt, &fl))) { +#else + if ((err=ip_route_output_key(&init_net,&rt, &fl))) { +#endif + goto tx_error; + } + } +#endif +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,36) + tdev = rt->u.dst.dev; +#else + tdev = rt->dst.dev; +#endif + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + max_headroom = ((tdev->hard_header_len+15)&~15) + sizeof(*iph)+sizeof(*hdr)+2; +#else + max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(*iph)+sizeof(*hdr)+2; +#endif + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22) + if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) { +#else + if (skb_headroom(skb) < max_headroom || skb_shared(skb) || + (skb_cloned(skb) && !skb_clone_writable(skb,0))) { +#endif + struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom); + if (!new_skb) { + ip_rt_put(rt); + goto tx_error; + } + if (skb->sk) + skb_set_owner_w(new_skb, skb->sk); + kfree_skb(skb); + skb = new_skb; + } + + data=skb->data; + islcp=((data[0] << 8) + data[1])== PPP_LCP && 1 <= data[2] && data[2] <= 7; + + /* compress protocol field */ + if ((opt->ppp_flags & SC_COMP_PROT) && data[0]==0 && !islcp) + skb_pull(skb,1); + + /* + * Put in the address/control bytes if necessary + */ + if ((opt->ppp_flags & SC_COMP_AC) == 0 || islcp) { + data=skb_push(skb,2); + data[0]=PPP_ALLSTATIONS; + data[1]=PPP_UI; + } + + len=skb->len; + + seq_recv = opt->seq_recv; + + if (opt->ack_sent == seq_recv) header_len-=sizeof(hdr->ack); + + // Push down and install GRE header + skb_push(skb,header_len); + hdr=(struct pptp_gre_header *)(skb->data); + + hdr->flags = PPTP_GRE_FLAG_K; + hdr->ver = PPTP_GRE_VER; + hdr->protocol = htons(PPTP_GRE_PROTO); + hdr->call_id = htons(opt->dst_addr.call_id); + + hdr->flags |= PPTP_GRE_FLAG_S; + hdr->seq = htonl(++opt->seq_sent); +#ifdef DEBUG + if (log_level>=3 && opt->seq_sent<=log_packets) + printk(KERN_INFO"PPTP[%i]: send packet: seq=%i",opt->src_addr.call_id,opt->seq_sent); +#endif + if (opt->ack_sent != seq_recv) { + /* send ack with this message */ + hdr->ver |= PPTP_GRE_FLAG_A; + hdr->ack = htonl(seq_recv); + opt->ack_sent = seq_recv; +#ifdef DEBUG + if (log_level>=3 && opt->seq_sent<=log_packets) + printk(" ack=%i",seq_recv); +#endif + } + hdr->payload_len = htons(len); +#ifdef DEBUG + if (log_level>=3 && opt->seq_sent<=log_packets) + printk("\n"); +#endif + + /* + * Push down and install the IP header. + */ + +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,31) + skb_reset_transport_header(skb); + skb_push(skb, sizeof(*iph)); + skb_reset_network_header(skb); +#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22) + skb->transport_header = skb->network_header; + skb_push(skb, sizeof(*iph)); + skb_reset_network_header(skb); +#else + skb->h.raw = skb->nh.raw; + skb->nh.raw = skb_push(skb, sizeof(*iph)); +#endif + memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16) + IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | + IPSKB_REROUTED); +#endif + +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22) + iph = ip_hdr(skb); +#else + iph = skb->nh.iph; +#endif + iph->version = 4; + iph->ihl = sizeof(struct iphdr) >> 2; +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,36) + if (ip_dont_fragment(sk, &rt->u.dst)) +#else + if (ip_dont_fragment(sk, &rt->dst)) +#endif + iph->frag_off = htons(IP_DF); + else + iph->frag_off = 0; + iph->protocol = IPPROTO_GRE; + iph->tos = 0; + iph->daddr = rt->rt_dst; + iph->saddr = rt->rt_src; +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + iph->ttl = sk->protinfo.af_inet.ttl; +#else +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,36) + iph->ttl = dst_metric(&rt->u.dst, RTAX_HOPLIMIT); +#else + iph->ttl = dst_metric(&rt->dst, RTAX_HOPLIMIT); +#endif +#endif + iph->tot_len = htons(skb->len); + +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,31) + skb_dst_drop(skb); +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,36) + skb_dst_set(skb,&rt->u.dst); +#else + skb_dst_set(skb,&rt->dst); +#endif +#else + dst_release(skb->dst); + skb->dst = &rt->u.dst; +#endif + + nf_reset(skb); + + skb->ip_summed = CHECKSUM_NONE; +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,36) + ip_select_ident(iph, &rt->u.dst, NULL); +#else + ip_select_ident(iph, &rt->dst, NULL); +#endif + ip_send_check(iph); + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + err = NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, ip_send); +#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25) + err = NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, dst_output); +#else + err = ip_local_out(skb); +#endif + +tx_error: + return 1; +} + +static int pptp_rcv_core(struct sock *sk,struct sk_buff *skb) +{ + struct pppox_sock *po = pppox_sk(sk); + struct pptp_opt *opt=&po->proto.pptp; + int headersize,payload_len,seq; + u8 *payload; + struct pptp_gre_header *header; + + if (!(SK_STATE(sk) & PPPOX_CONNECTED)) { + if (sock_queue_rcv_skb(sk, skb)) + goto drop; + return NET_RX_SUCCESS; + } + + header = (struct pptp_gre_header *)(skb->data); + + /* test if acknowledgement present */ + if (PPTP_GRE_IS_A(header->ver)){ + u32 ack = (PPTP_GRE_IS_S(header->flags))? + header->ack:header->seq; /* ack in different place if S = 0 */ + + ack = ntohl( ack); + + if (ack > opt->ack_recv) opt->ack_recv = ack; + /* also handle sequence number wrap-around */ + if (WRAPPED(ack,opt->ack_recv)) opt->ack_recv = ack; + } + + /* test if payload present */ + if (!PPTP_GRE_IS_S(header->flags)){ + goto drop; + } + + headersize = sizeof(*header); + payload_len = ntohs(header->payload_len); + seq = ntohl(header->seq); + + /* no ack present? */ + if (!PPTP_GRE_IS_A(header->ver)) headersize -= sizeof(header->ack); + /* check for incomplete packet (length smaller than expected) */ + if (skb->len - headersize < payload_len){ +#ifdef DEBUG + if (log_level>=1) + printk(KERN_INFO"PPTP: discarding truncated packet (expected %d, got %d bytes)\n", + payload_len, skb->len - headersize); +#endif + goto drop; + } + + payload=skb->data+headersize; + /* check for expected sequence number */ + if ( seq < opt->seq_recv + 1 || WRAPPED(opt->seq_recv, seq) ){ + if ( (payload[0] == PPP_ALLSTATIONS) && (payload[1] == PPP_UI) && + (PPP_PROTOCOL(payload) == PPP_LCP) && + ((payload[4] == PPP_LCP_ECHOREQ) || (payload[4] == PPP_LCP_ECHOREP)) ){ +#ifdef DEBUG + if ( log_level >= 1) + printk(KERN_INFO"PPTP[%i]: allowing old LCP Echo packet %d (expecting %d)\n", opt->src_addr.call_id, + seq, opt->seq_recv + 1); +#endif + goto allow_packet; + } +#ifdef DEBUG + if ( log_level >= 1) + printk(KERN_INFO"PPTP[%i]: discarding duplicate or old packet %d (expecting %d)\n",opt->src_addr.call_id, + seq, opt->seq_recv + 1); +#endif + }else{ + opt->seq_recv = seq; +allow_packet: +#ifdef DEBUG + if ( log_level >= 3 && opt->seq_sent<=log_packets) + printk(KERN_INFO"PPTP[%i]: accepting packet %d size=%i (%02x %02x %02x %02x %02x %02x)\n",opt->src_addr.call_id, seq,payload_len, + *(payload +0), + *(payload +1), + *(payload +2), + *(payload +3), + *(payload +4), + *(payload +5)); +#endif + + skb_pull(skb,headersize); + + if (payload[0] == PPP_ALLSTATIONS && payload[1] == PPP_UI){ + /* chop off address/control */ + if (skb->len < 3) + goto drop; + skb_pull(skb,2); + } + + if ((*skb->data) & 1){ + /* protocol is compressed */ + skb_push(skb, 1)[0] = 0; + } + + skb->ip_summed=CHECKSUM_NONE; +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,21) + skb_set_network_header(skb,skb->head-skb->data); +#endif + ppp_input(&po->chan,skb); + + return NET_RX_SUCCESS; + } +drop: + kfree_skb(skb); + return NET_RX_DROP; +} + +static int pptp_rcv(struct sk_buff *skb) +{ + struct pppox_sock *po; + struct pptp_gre_header *header; + struct iphdr *iph; +#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,0) + int ret; + struct sock *sk; +#endif + + if (skb->pkt_type != PACKET_HOST) + goto drop; + + /*if (!pskb_may_pull(skb, 12)) + goto drop;*/ + +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22) + iph = ip_hdr(skb); +#else + iph = skb->nh.iph; +#endif + + header = (struct pptp_gre_header *)skb->data; + + if ( /* version should be 1 */ + ((header->ver & 0x7F) != PPTP_GRE_VER) || + /* PPTP-GRE protocol for PPTP */ + (ntohs(header->protocol) != PPTP_GRE_PROTO)|| + /* flag C should be clear */ + PPTP_GRE_IS_C(header->flags) || + /* flag R should be clear */ + PPTP_GRE_IS_R(header->flags) || + /* flag K should be set */ + (!PPTP_GRE_IS_K(header->flags)) || + /* routing and recursion ctrl = 0 */ + ((header->flags&0xF) != 0)){ + /* if invalid, discard this packet */ + if (log_level>=1) + printk(KERN_INFO"PPTP: Discarding GRE: %X %X %X %X %X %X\n", + header->ver&0x7F, ntohs(header->protocol), + PPTP_GRE_IS_C(header->flags), + PPTP_GRE_IS_R(header->flags), + PPTP_GRE_IS_K(header->flags), + header->flags & 0xF); + goto drop; + } + + + if ((po=lookup_chan(htons(header->call_id),iph->saddr))) { +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,31) + skb_dst_drop(skb); +#else + dst_release(skb->dst); + skb->dst = NULL; +#endif + nf_reset(skb); +#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,0) + sk=sk_pppox(po); + bh_lock_sock(sk); + /* Socket state is unknown, must put skb into backlog. */ + if (sk->lock.users != 0) { + sk_add_backlog(sk, skb); + ret = NET_RX_SUCCESS; + } else { + ret = pptp_rcv_core(sk, skb); + } + bh_unlock_sock(sk); + sock_put(sk); + return ret; + +#else /* LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,0) */ + +#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,19) + return sk_receive_skb(sk_pppox(po), skb); +#else + return sk_receive_skb(sk_pppox(po), skb, 0); +#endif + +#endif /* LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,0) */ + }else { +#ifdef DEBUG + if (log_level>=1) + printk(KERN_INFO"PPTP: Discarding packet from unknown call_id %i\n",htons(header->call_id)); +#endif + } + +drop: + kfree_skb(skb); + return NET_RX_DROP; +} + +static int pptp_bind(struct socket *sock,struct sockaddr *uservaddr,int sockaddr_len) +{ + struct sock *sk = sock->sk; + struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr; + struct pppox_sock *po = pppox_sk(sk); + struct pptp_opt *opt=&po->proto.pptp; + int error=0; + +#ifdef DEBUG + if (log_level>=1) + printk(KERN_INFO"PPTP: bind: addr=%X call_id=%i\n",sp->sa_addr.pptp.sin_addr.s_addr, + sp->sa_addr.pptp.call_id); +#endif + lock_sock(sk); + + opt->src_addr=sp->sa_addr.pptp; + if (add_chan(po)) + { + release_sock(sk); + error=-EBUSY; + } +#ifdef DEBUG + if (log_level>=1) + printk(KERN_INFO"PPTP: using call_id %i\n",opt->src_addr.call_id); +#endif + + release_sock(sk); + return error; +} + +static int pptp_connect(struct socket *sock, struct sockaddr *uservaddr, + int sockaddr_len, int flags) +{ + struct sock *sk = sock->sk; + struct sockaddr_pppox *sp = (struct sockaddr_pppox *) uservaddr; + struct pppox_sock *po = pppox_sk(sk); + struct pptp_opt *opt = &po->proto.pptp; + struct rtable *rt; /* Route to the other host */ + int error=0; + + if (sp->sa_protocol != PX_PROTO_PPTP) + return -EINVAL; + +#ifdef DEBUG + if (log_level>=1) + printk(KERN_INFO"PPTP[%i]: connect: addr=%X call_id=%i\n",opt->src_addr.call_id, + sp->sa_addr.pptp.sin_addr.s_addr,sp->sa_addr.pptp.call_id); +#endif + + if (lookup_chan_dst(sp->sa_addr.pptp.call_id,sp->sa_addr.pptp.sin_addr.s_addr)) + return -EALREADY; + + lock_sock(sk); + /* Check for already bound sockets */ + if (SK_STATE(sk) & PPPOX_CONNECTED){ + error = -EBUSY; + goto end; + } + + /* Check for already disconnected sockets, on attempts to disconnect */ + if (SK_STATE(sk) & PPPOX_DEAD){ + error = -EALREADY; + goto end; + } + + if (!opt->src_addr.sin_addr.s_addr || !sp->sa_addr.pptp.sin_addr.s_addr){ + error = -EINVAL; + goto end; + } + + po->chan.private=sk; + po->chan.ops=&pptp_chan_ops; + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + { + struct rt_key key = { + .dst=opt->dst_addr.sin_addr.s_addr, + .src=opt->src_addr.sin_addr.s_addr, + .tos=RT_TOS(0), + }; +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25) + if (ip_route_output_key(&rt, &key)) { +#else + if (ip_route_output_key(&init_net, &rt, &key)) { +#endif + error = -EHOSTUNREACH; + goto end; + } + } +#else + { + struct flowi fl = { + .nl_u = { .ip4_u = + { .daddr = opt->dst_addr.sin_addr.s_addr, + .saddr = opt->src_addr.sin_addr.s_addr, + .tos = RT_CONN_FLAGS(sk) } }, + .proto = IPPROTO_GRE }; +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,18) + security_sk_classify_flow(sk, &fl); +#endif +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25) + if (ip_route_output_key(&rt, &fl)){ +#else + if (ip_route_output_key(&init_net, &rt, &fl)){ +#endif + error = -EHOSTUNREACH; + goto end; + } +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,36) + sk_setup_caps(sk, &rt->u.dst); +#else + sk_setup_caps(sk, &rt->dst); +#endif + } +#endif +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + po->chan.mtu=PPP_MTU; +#else +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,36) + po->chan.mtu=dst_mtu(&rt->u.dst); +#else + po->chan.mtu=dst_mtu(&rt->dst); +#endif + if (!po->chan.mtu) po->chan.mtu=PPP_MTU; +#endif + ip_rt_put(rt); + po->chan.mtu-=PPTP_HEADER_OVERHEAD; + + po->chan.hdrlen=2+sizeof(struct pptp_gre_header); + error = ppp_register_channel(&po->chan); + if (error){ + printk(KERN_ERR "PPTP: failed to register PPP channel (%d)\n",error); + goto end; + } + + opt->dst_addr=sp->sa_addr.pptp; + SK_STATE(sk) = PPPOX_CONNECTED; + + end: + release_sock(sk); + return error; +} + +static int pptp_getname(struct socket *sock, struct sockaddr *uaddr, + int *usockaddr_len, int peer) +{ + int len = sizeof(struct sockaddr_pppox); + struct sockaddr_pppox sp; + + sp.sa_family = AF_PPPOX; + sp.sa_protocol = PX_PROTO_PPTP; + sp.sa_addr.pptp=pppox_sk(sock->sk)->proto.pptp.src_addr; + + memcpy(uaddr, &sp, len); + + *usockaddr_len = len; + + return 0; +} + +static int pptp_release(struct socket *sock) +{ + struct sock *sk = sock->sk; + struct pppox_sock *po; + struct pptp_opt *opt; + int error = 0; + + if (!sk) + return 0; + + lock_sock(sk); + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + if (sk->dead) +#else + if (sock_flag(sk, SOCK_DEAD)) +#endif + { + release_sock(sk); + return -EBADF; + } + + po = pppox_sk(sk); + opt=&po->proto.pptp; + del_chan(po); + + pppox_unbind_sock(sk); + SK_STATE(sk) = PPPOX_DEAD; + +#ifdef DEBUG + if (log_level>=1) + printk(KERN_INFO"PPTP[%i]: release\n",opt->src_addr.call_id); +#endif + + sock_orphan(sk); + sock->sk = NULL; + + release_sock(sk); + sock_put(sk); + + return error; +} + + +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) +static struct proto pptp_sk_proto = { + .name = "PPTP", + .owner = THIS_MODULE, + .obj_size = sizeof(struct pppox_sock), +}; +#endif + +static struct proto_ops pptp_ops = { + .family = AF_PPPOX, +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + .owner = THIS_MODULE, +#endif + .release = pptp_release, + .bind = pptp_bind, + .connect = pptp_connect, + .socketpair = sock_no_socketpair, + .accept = sock_no_accept, + .getname = pptp_getname, + .poll = sock_no_poll, + .listen = sock_no_listen, + .shutdown = sock_no_shutdown, + .setsockopt = sock_no_setsockopt, + .getsockopt = sock_no_getsockopt, + .sendmsg = sock_no_sendmsg, + .recvmsg = sock_no_recvmsg, + .mmap = sock_no_mmap, +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16) + .ioctl = pppox_ioctl, +#endif +}; + + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) +static void pptp_sock_destruct(struct sock *sk) +{ + skb_queue_purge(&sk->receive_queue); + if (!(SK_STATE(sk) & PPPOX_DEAD)) { + del_chan(pppox_sk(sk)); + pppox_unbind_sock(sk); + } + if (sk->protinfo.destruct_hook) + kfree(sk->protinfo.destruct_hook); + + MOD_DEC_USE_COUNT; +} + +static int pptp_create(struct socket *sock) +{ + int error = -ENOMEM; + struct sock *sk; + struct pppox_sock *po; + struct pptp_opt *opt; + + MOD_INC_USE_COUNT; + + sk = sk_alloc(PF_PPPOX, GFP_KERNEL, 1); + if (!sk) + goto out; + + sock_init_data(sock, sk); + + sock->state = SS_UNCONNECTED; + sock->ops = &pptp_ops; + + //sk->sk_backlog_rcv = pppoe_rcv_core; + sk->state = PPPOX_NONE; + sk->type = SOCK_STREAM; + sk->family = PF_PPPOX; + sk->protocol = PX_PROTO_PPTP; + + sk->protinfo.pppox=kzalloc(sizeof(struct pppox_sock),GFP_KERNEL); + sk->destruct=pptp_sock_destruct; + sk->protinfo.destruct_hook=sk->protinfo.pppox; + + po = pppox_sk(sk); + po->sk=sk; + opt=&po->proto.pptp; + + opt->seq_sent=0; opt->seq_recv=0; + opt->ack_recv=0; opt->ack_sent=0; + + error = 0; +out: + return error; +} +#else +static void pptp_sock_destruct(struct sock *sk) +{ + if (!(SK_STATE(sk) & PPPOX_DEAD)){ + del_chan(pppox_sk(sk)); + pppox_unbind_sock(sk); + } + skb_queue_purge(&sk->sk_receive_queue); +} +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24) +static int pptp_create(struct socket *sock) +#else +static int pptp_create(struct net *net, struct socket *sock) +#endif +{ + int error = -ENOMEM; + struct sock *sk; + struct pppox_sock *po; + struct pptp_opt *opt; + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24) + sk = sk_alloc(PF_PPPOX, GFP_KERNEL, &pptp_sk_proto, 1); +#else + sk = sk_alloc(net,PF_PPPOX, GFP_KERNEL, &pptp_sk_proto); +#endif + if (!sk) + goto out; + + sock_init_data(sock, sk); + + sock->state = SS_UNCONNECTED; + sock->ops = &pptp_ops; + + sk->sk_backlog_rcv = pptp_rcv_core; + sk->sk_state = PPPOX_NONE; + sk->sk_type = SOCK_STREAM; + sk->sk_family = PF_PPPOX; + sk->sk_protocol = PX_PROTO_PPTP; + sk->sk_destruct = pptp_sock_destruct; + + po = pppox_sk(sk); +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + po->sk=sk; +#endif + opt=&po->proto.pptp; + + opt->seq_sent=0; opt->seq_recv=0; + opt->ack_recv=0; opt->ack_sent=0; + + error = 0; +out: + return error; +} +#endif + + +static int pptp_ppp_ioctl(struct ppp_channel *chan, unsigned int cmd, + unsigned long arg) +{ + struct sock *sk = (struct sock *) chan->private; + struct pppox_sock *po = pppox_sk(sk); + struct pptp_opt *opt=&po->proto.pptp; + void __user *argp = (void __user *)arg; + int __user *p = argp; + int err, val; + + err = -EFAULT; + switch (cmd) { + case PPPIOCGFLAGS: + val = opt->ppp_flags; + if (put_user(val, p)) + break; + err = 0; + break; + case PPPIOCSFLAGS: + if (get_user(val, p)) + break; + opt->ppp_flags = val & ~SC_RCV_BITS; + err = 0; + break; + default: + err = -ENOTTY; + } + + return err; +} + + +static struct pppox_proto pppox_pptp_proto = { + .create = pptp_create, +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,15) + .owner = THIS_MODULE, +#endif +}; + +#if defined(CONFIG_GRE) || defined(CONFIG_GRE_MODULE) +static struct gre_protocol gre_pptp_protocol = { + .handler = pptp_rcv, +}; +#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) +static struct inet_protocol net_pptp_protocol = { + .handler = pptp_rcv, + .protocol = IPPROTO_GRE, + .name = "PPTP", +}; +#else +static struct net_protocol net_pptp_protocol = { + .handler = pptp_rcv, +}; +#endif + +static int __init pptp_init_module(void) +{ + int err=0; + printk(KERN_INFO "PPTP driver version " PPTP_DRIVER_VERSION "\n"); + +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + callid_sock = __vmalloc((MAX_CALLID + 1) * sizeof(void *), + GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL); +#else + callid_sock = __vmalloc((MAX_CALLID + 1) * sizeof(void *), + GFP_KERNEL, PAGE_KERNEL); + memset(callid_sock, 0, (MAX_CALLID + 1) * sizeof(void *)); +#endif + if (!callid_sock) { + printk(KERN_ERR "PPTP: cann't allocate memory\n"); + return -ENOMEM; + } + +#if defined(CONFIG_GRE) || defined(CONFIG_GRE_MODULE) + if (gre_add_protocol(&gre_pptp_protocol, GREPROTO_PPTP) < 0) { + printk(KERN_INFO "PPTP: can't add protocol\n"); + goto out_free_mem; + } +#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + inet_add_protocol(&net_pptp_protocol); +#else + if (inet_add_protocol(&net_pptp_protocol, IPPROTO_GRE) < 0) { + printk(KERN_INFO "PPTP: can't add protocol\n"); + goto out_free_mem; + } +#endif + +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + err = proto_register(&pptp_sk_proto, 0); + if (err){ + printk(KERN_INFO "PPTP: can't register sk_proto\n"); + goto out_inet_del_protocol; + } +#endif + + err = register_pppox_proto(PX_PROTO_PPTP, &pppox_pptp_proto); + if (err){ + printk(KERN_INFO "PPTP: can't register pppox_proto\n"); + goto out_unregister_sk_proto; + } + + return 0; +out_unregister_sk_proto: +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + proto_unregister(&pptp_sk_proto); +#endif + +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) +out_inet_del_protocol: +#endif + +#if defined(CONFIG_GRE) || defined(CONFIG_GRE_MODULE) + gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP); +#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + inet_del_protocol(&net_pptp_protocol); +#else + inet_del_protocol(&net_pptp_protocol, IPPROTO_GRE); +#endif +out_free_mem: + vfree(callid_sock); + + return err; +} + +static void __exit pptp_exit_module(void) +{ + unregister_pppox_proto(PX_PROTO_PPTP); +#if defined(CONFIG_GRE) || defined(CONFIG_GRE_MODULE) +#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,0) + proto_unregister(&pptp_sk_proto); +#endif + gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP); +#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) + inet_del_protocol(&net_pptp_protocol); +#else + proto_unregister(&pptp_sk_proto); + inet_del_protocol(&net_pptp_protocol, IPPROTO_GRE); +#endif + vfree(callid_sock); +} + +module_init(pptp_init_module); +module_exit(pptp_exit_module); + +MODULE_DESCRIPTION("Point-to-Point Tunneling Protocol for Linux"); +MODULE_AUTHOR("Kozlov D. (xeb@mail.ru)"); +MODULE_LICENSE("GPL"); + +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0) +MODULE_PARM(log_level,"i"); +MODULE_PARM(log_packets,"i"); +#else +module_param(log_level,int,0); +module_param(log_packets,int,0); +#endif +MODULE_PARM_DESC(log_level,"Logging level (default=0)"); + |