diff options
Diffstat (limited to 'net/l2tp/pppol2tp.c')
| -rw-r--r-- | net/l2tp/pppol2tp.c | 2680 |
1 files changed, 0 insertions, 2680 deletions
diff --git a/net/l2tp/pppol2tp.c b/net/l2tp/pppol2tp.c deleted file mode 100644 index 449a9825200..00000000000 --- a/net/l2tp/pppol2tp.c +++ /dev/null @@ -1,2680 +0,0 @@ -/***************************************************************************** - * Linux PPP over L2TP (PPPoX/PPPoL2TP) Sockets - * - * PPPoX --- Generic PPP encapsulation socket family - * PPPoL2TP --- PPP over L2TP (RFC 2661) - * - * Version: 1.0.0 - * - * Authors: Martijn van Oosterhout <kleptog@svana.org> - * James Chapman (jchapman@katalix.com) - * Contributors: - * Michal Ostrowski <mostrows@speakeasy.net> - * Arnaldo Carvalho de Melo <acme@xconectiva.com.br> - * David S. Miller (davem@redhat.com) - * - * License: - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version - * 2 of the License, or (at your option) any later version. - * - */ - -/* This driver handles only L2TP data frames; control frames are handled by a - * userspace application. - * - * To send data in an L2TP session, userspace opens a PPPoL2TP socket and - * attaches it to a bound UDP socket with local tunnel_id / session_id and - * peer tunnel_id / session_id set. Data can then be sent or received using - * regular socket sendmsg() / recvmsg() calls. Kernel parameters of the socket - * can be read or modified using ioctl() or [gs]etsockopt() calls. - * - * When a PPPoL2TP socket is connected with local and peer session_id values - * zero, the socket is treated as a special tunnel management socket. - * - * Here's example userspace code to create a socket for sending/receiving data - * over an L2TP session:- - * - * struct sockaddr_pppol2tp sax; - * int fd; - * int session_fd; - * - * fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP); - * - * sax.sa_family = AF_PPPOX; - * sax.sa_protocol = PX_PROTO_OL2TP; - * sax.pppol2tp.fd = tunnel_fd; // bound UDP socket - * sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr; - * sax.pppol2tp.addr.sin_port = addr->sin_port; - * sax.pppol2tp.addr.sin_family = AF_INET; - * sax.pppol2tp.s_tunnel = tunnel_id; - * sax.pppol2tp.s_session = session_id; - * sax.pppol2tp.d_tunnel = peer_tunnel_id; - * sax.pppol2tp.d_session = peer_session_id; - * - * session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax)); - * - * A pppd plugin that allows PPP traffic to be carried over L2TP using - * this driver is available from the OpenL2TP project at - * http://openl2tp.sourceforge.net. - */ - -#include <linux/module.h> -#include <linux/string.h> -#include <linux/list.h> -#include <asm/uaccess.h> - -#include <linux/kernel.h> -#include <linux/spinlock.h> -#include <linux/kthread.h> -#include <linux/sched.h> -#include <linux/slab.h> -#include <linux/errno.h> -#include <linux/jiffies.h> - -#include <linux/netdevice.h> -#include <linux/net.h> -#include <linux/inetdevice.h> -#include <linux/skbuff.h> -#include <linux/init.h> -#include <linux/ip.h> -#include <linux/udp.h> -#include <linux/if_pppox.h> -#include <linux/if_pppol2tp.h> -#include <net/sock.h> -#include <linux/ppp_channel.h> -#include <linux/ppp_defs.h> -#include <linux/if_ppp.h> -#include <linux/file.h> -#include <linux/hash.h> -#include <linux/sort.h> -#include <linux/proc_fs.h> -#include <linux/nsproxy.h> -#include <net/net_namespace.h> -#include <net/netns/generic.h> -#include <net/dst.h> -#include <net/ip.h> -#include <net/udp.h> -#include <net/xfrm.h> - -#include <asm/byteorder.h> -#include <asm/atomic.h> - - -#define PPPOL2TP_DRV_VERSION "V1.0" - -/* L2TP header constants */ -#define L2TP_HDRFLAG_T 0x8000 -#define L2TP_HDRFLAG_L 0x4000 -#define L2TP_HDRFLAG_S 0x0800 -#define L2TP_HDRFLAG_O 0x0200 -#define L2TP_HDRFLAG_P 0x0100 - -#define L2TP_HDR_VER_MASK 0x000F -#define L2TP_HDR_VER 0x0002 - -/* Space for UDP, L2TP and PPP headers */ -#define PPPOL2TP_HEADER_OVERHEAD 40 - -/* Just some random numbers */ -#define L2TP_TUNNEL_MAGIC 0x42114DDA -#define L2TP_SESSION_MAGIC 0x0C04EB7D - -#define PPPOL2TP_HASH_BITS 4 -#define PPPOL2TP_HASH_SIZE (1 << PPPOL2TP_HASH_BITS) - -/* Default trace flags */ -#define PPPOL2TP_DEFAULT_DEBUG_FLAGS 0 - -#define PRINTK(_mask, _type, _lvl, _fmt, args...) \ - do { \ - if ((_mask) & (_type)) \ - printk(_lvl "PPPOL2TP: " _fmt, ##args); \ - } while(0) - -/* Number of bytes to build transmit L2TP headers. - * Unfortunately the size is different depending on whether sequence numbers - * are enabled. - */ -#define PPPOL2TP_L2TP_HDR_SIZE_SEQ 10 -#define PPPOL2TP_L2TP_HDR_SIZE_NOSEQ 6 - -struct pppol2tp_tunnel; - -/* Describes a session. It is the sk_user_data field in the PPPoL2TP - * socket. Contains information to determine incoming packets and transmit - * outgoing ones. - */ -struct pppol2tp_session -{ - int magic; /* should be - * L2TP_SESSION_MAGIC */ - int owner; /* pid that opened the socket */ - - struct sock *sock; /* Pointer to the session - * PPPoX socket */ - struct sock *tunnel_sock; /* Pointer to the tunnel UDP - * socket */ - - struct pppol2tp_addr tunnel_addr; /* Description of tunnel */ - - struct pppol2tp_tunnel *tunnel; /* back pointer to tunnel - * context */ - - char name[20]; /* "sess xxxxx/yyyyy", where - * x=tunnel_id, y=session_id */ - int mtu; - int mru; - int flags; /* accessed by PPPIOCGFLAGS. - * Unused. */ - unsigned recv_seq:1; /* expect receive packets with - * sequence numbers? */ - unsigned send_seq:1; /* send packets with sequence - * numbers? */ - unsigned lns_mode:1; /* behave as LNS? LAC enables - * sequence numbers under - * control of LNS. */ - int debug; /* bitmask of debug message - * categories */ - int reorder_timeout; /* configured reorder timeout - * (in jiffies) */ - u16 nr; /* session NR state (receive) */ - u16 ns; /* session NR state (send) */ - struct sk_buff_head reorder_q; /* receive reorder queue */ - struct pppol2tp_ioc_stats stats; - struct hlist_node hlist; /* Hash list node */ -}; - -/* The sk_user_data field of the tunnel's UDP socket. It contains info to track - * all the associated sessions so incoming packets can be sorted out - */ -struct pppol2tp_tunnel -{ - int magic; /* Should be L2TP_TUNNEL_MAGIC */ - rwlock_t hlist_lock; /* protect session_hlist */ - struct hlist_head session_hlist[PPPOL2TP_HASH_SIZE]; - /* hashed list of sessions, - * hashed by id */ - int debug; /* bitmask of debug message - * categories */ - char name[12]; /* "tunl xxxxx" */ - struct pppol2tp_ioc_stats stats; - - void (*old_sk_destruct)(struct sock *); - - struct sock *sock; /* Parent socket */ - struct list_head list; /* Keep a list of all open - * prepared sockets */ - struct net *pppol2tp_net; /* the net we belong to */ - - atomic_t ref_count; -}; - -/* Private data stored for received packets in the skb. - */ -struct pppol2tp_skb_cb { - u16 ns; - u16 nr; - u16 has_seq; - u16 length; - unsigned long expires; -}; - -#define PPPOL2TP_SKB_CB(skb) ((struct pppol2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)]) - -static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb); -static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel); - -static atomic_t pppol2tp_tunnel_count; -static atomic_t pppol2tp_session_count; -static struct ppp_channel_ops pppol2tp_chan_ops = { pppol2tp_xmit , NULL }; -static const struct proto_ops pppol2tp_ops; - -/* per-net private data for this module */ -static int pppol2tp_net_id __read_mostly; -struct pppol2tp_net { - struct list_head pppol2tp_tunnel_list; - rwlock_t pppol2tp_tunnel_list_lock; -}; - -static inline struct pppol2tp_net *pppol2tp_pernet(struct net *net) -{ - BUG_ON(!net); - - return net_generic(net, pppol2tp_net_id); -} - -/* Helpers to obtain tunnel/session contexts from sockets. - */ -static inline struct pppol2tp_session *pppol2tp_sock_to_session(struct sock *sk) -{ - struct pppol2tp_session *session; - - if (sk == NULL) - return NULL; - - sock_hold(sk); - session = (struct pppol2tp_session *)(sk->sk_user_data); - if (session == NULL) { - sock_put(sk); - goto out; - } - - BUG_ON(session->magic != L2TP_SESSION_MAGIC); -out: - return session; -} - -static inline struct pppol2tp_tunnel *pppol2tp_sock_to_tunnel(struct sock *sk) -{ - struct pppol2tp_tunnel *tunnel; - - if (sk == NULL) - return NULL; - - sock_hold(sk); - tunnel = (struct pppol2tp_tunnel *)(sk->sk_user_data); - if (tunnel == NULL) { - sock_put(sk); - goto out; - } - - BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); -out: - return tunnel; -} - -/* Tunnel reference counts. Incremented per session that is added to - * the tunnel. - */ -static inline void pppol2tp_tunnel_inc_refcount(struct pppol2tp_tunnel *tunnel) -{ - atomic_inc(&tunnel->ref_count); -} - -static inline void pppol2tp_tunnel_dec_refcount(struct pppol2tp_tunnel *tunnel) -{ - if (atomic_dec_and_test(&tunnel->ref_count)) - pppol2tp_tunnel_free(tunnel); -} - -/* Session hash list. - * The session_id SHOULD be random according to RFC2661, but several - * L2TP implementations (Cisco and Microsoft) use incrementing - * session_ids. So we do a real hash on the session_id, rather than a - * simple bitmask. - */ -static inline struct hlist_head * -pppol2tp_session_id_hash(struct pppol2tp_tunnel *tunnel, u16 session_id) -{ - unsigned long hash_val = (unsigned long) session_id; - return &tunnel->session_hlist[hash_long(hash_val, PPPOL2TP_HASH_BITS)]; -} - -/* Lookup a session by id - */ -static struct pppol2tp_session * -pppol2tp_session_find(struct pppol2tp_tunnel *tunnel, u16 session_id) -{ - struct hlist_head *session_list = - pppol2tp_session_id_hash(tunnel, session_id); - struct pppol2tp_session *session; - struct hlist_node *walk; - - read_lock_bh(&tunnel->hlist_lock); - hlist_for_each_entry(session, walk, session_list, hlist) { - if (session->tunnel_addr.s_session == session_id) { - read_unlock_bh(&tunnel->hlist_lock); - return session; - } - } - read_unlock_bh(&tunnel->hlist_lock); - - return NULL; -} - -/* Lookup a tunnel by id - */ -static struct pppol2tp_tunnel *pppol2tp_tunnel_find(struct net *net, u16 tunnel_id) -{ - struct pppol2tp_tunnel *tunnel; - struct pppol2tp_net *pn = pppol2tp_pernet(net); - - read_lock_bh(&pn->pppol2tp_tunnel_list_lock); - list_for_each_entry(tunnel, &pn->pppol2tp_tunnel_list, list) { - if (tunnel->stats.tunnel_id == tunnel_id) { - read_unlock_bh(&pn->pppol2tp_tunnel_list_lock); - return tunnel; - } - } - read_unlock_bh(&pn->pppol2tp_tunnel_list_lock); - - return NULL; -} - -/***************************************************************************** - * Receive data handling - *****************************************************************************/ - -/* Queue a skb in order. We come here only if the skb has an L2TP sequence - * number. - */ -static void pppol2tp_recv_queue_skb(struct pppol2tp_session *session, struct sk_buff *skb) -{ - struct sk_buff *skbp; - struct sk_buff *tmp; - u16 ns = PPPOL2TP_SKB_CB(skb)->ns; - - spin_lock_bh(&session->reorder_q.lock); - skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { - if (PPPOL2TP_SKB_CB(skbp)->ns > ns) { - __skb_queue_before(&session->reorder_q, skbp, skb); - PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG, - "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n", - session->name, ns, PPPOL2TP_SKB_CB(skbp)->ns, - skb_queue_len(&session->reorder_q)); - session->stats.rx_oos_packets++; - goto out; - } - } - - __skb_queue_tail(&session->reorder_q, skb); - -out: - spin_unlock_bh(&session->reorder_q.lock); -} - -/* Dequeue a single skb. - */ -static void pppol2tp_recv_dequeue_skb(struct pppol2tp_session *session, struct sk_buff *skb) -{ - struct pppol2tp_tunnel *tunnel = session->tunnel; - int length = PPPOL2TP_SKB_CB(skb)->length; - struct sock *session_sock = NULL; - - /* We're about to requeue the skb, so return resources - * to its current owner (a socket receive buffer). - */ - skb_orphan(skb); - - tunnel->stats.rx_packets++; - tunnel->stats.rx_bytes += length; - session->stats.rx_packets++; - session->stats.rx_bytes += length; - - if (PPPOL2TP_SKB_CB(skb)->has_seq) { - /* Bump our Nr */ - session->nr++; - PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG, - "%s: updated nr to %hu\n", session->name, session->nr); - } - - /* If the socket is bound, send it in to PPP's input queue. Otherwise - * queue it on the session socket. - */ - session_sock = session->sock; - if (session_sock->sk_state & PPPOX_BOUND) { - struct pppox_sock *po; - PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG, - "%s: recv %d byte data frame, passing to ppp\n", - session->name, length); - - /* We need to forget all info related to the L2TP packet - * gathered in the skb as we are going to reuse the same - * skb for the inner packet. - * Namely we need to: - * - reset xfrm (IPSec) information as it applies to - * the outer L2TP packet and not to the inner one - * - release the dst to force a route lookup on the inner - * IP packet since skb->dst currently points to the dst - * of the UDP tunnel - * - reset netfilter information as it doesn't apply - * to the inner packet either - */ - secpath_reset(skb); - skb_dst_drop(skb); - nf_reset(skb); - - po = pppox_sk(session_sock); - ppp_input(&po->chan, skb); - } else { - PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_INFO, - "%s: socket not bound\n", session->name); - - /* Not bound. Nothing we can do, so discard. */ - session->stats.rx_errors++; - kfree_skb(skb); - } - - sock_put(session->sock); -} - -/* Dequeue skbs from the session's reorder_q, subject to packet order. - * Skbs that have been in the queue for too long are simply discarded. - */ -static void pppol2tp_recv_dequeue(struct pppol2tp_session *session) -{ - struct sk_buff *skb; - struct sk_buff *tmp; - - /* If the pkt at the head of the queue has the nr that we - * expect to send up next, dequeue it and any other - * in-sequence packets behind it. - */ - spin_lock_bh(&session->reorder_q.lock); - skb_queue_walk_safe(&session->reorder_q, skb, tmp) { - if (time_after(jiffies, PPPOL2TP_SKB_CB(skb)->expires)) { - session->stats.rx_seq_discards++; - session->stats.rx_errors++; - PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG, - "%s: oos pkt %hu len %d discarded (too old), " - "waiting for %hu, reorder_q_len=%d\n", - session->name, PPPOL2TP_SKB_CB(skb)->ns, - PPPOL2TP_SKB_CB(skb)->length, session->nr, - skb_queue_len(&session->reorder_q)); - __skb_unlink(skb, &session->reorder_q); - kfree_skb(skb); - sock_put(session->sock); - continue; - } - - if (PPPOL2TP_SKB_CB(skb)->has_seq) { - if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) { - PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG, - "%s: holding oos pkt %hu len %d, " - "waiting for %hu, reorder_q_len=%d\n", - session->name, PPPOL2TP_SKB_CB(skb)->ns, - PPPOL2TP_SKB_CB(skb)->length, session->nr, - skb_queue_len(&session->reorder_q)); - goto out; - } - } - __skb_unlink(skb, &session->reorder_q); - - /* Process the skb. We release the queue lock while we - * do so to let other contexts process the queue. - */ - spin_unlock_bh(&session->reorder_q.lock); - pppol2tp_recv_dequeue_skb(session, skb); - spin_lock_bh(&session->reorder_q.lock); - } - -out: - spin_unlock_bh(&session->reorder_q.lock); -} - -static inline int pppol2tp_verify_udp_checksum(struct sock *sk, - struct sk_buff *skb) -{ - struct udphdr *uh = udp_hdr(skb); - u16 ulen = ntohs(uh->len); - struct inet_sock *inet; - __wsum psum; - - if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check) - return 0; - - inet = inet_sk(sk); - psum = csum_tcpudp_nofold(inet->inet_saddr, inet->inet_daddr, ulen, - IPPROTO_UDP, 0); - - if ((skb->ip_summed == CHECKSUM_COMPLETE) && - !csum_fold(csum_add(psum, skb->csum))) - return 0; - - skb->csum = psum; - - return __skb_checksum_complete(skb); -} - -/* Internal receive frame. Do the real work of receiving an L2TP data frame - * here. The skb is not on a list when we get here. - * Returns 0 if the packet was a data packet and was successfully passed on. - * Returns 1 if the packet was not a good data packet and could not be - * forwarded. All such packets are passed up to userspace to deal with. - */ -static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb) -{ - struct pppol2tp_session *session = NULL; - struct pppol2tp_tunnel *tunnel; - unsigned char *ptr, *optr; - u16 hdrflags; - u16 tunnel_id, session_id; - int length; - int offset; - - tunnel = pppol2tp_sock_to_tunnel(sock); - if (tunnel == NULL) - goto no_tunnel; - - if (tunnel->sock && pppol2tp_verify_udp_checksum(tunnel->sock, skb)) - goto discard_bad_csum; - - /* UDP always verifies the packet length. */ - __skb_pull(skb, sizeof(struct udphdr)); - - /* Short packet? */ - if (!pskb_may_pull(skb, 12)) { - PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO, - "%s: recv short packet (len=%d)\n", tunnel->name, skb->len); - goto error; - } - - /* Point to L2TP header */ - optr = ptr = skb->data; - - /* Get L2TP header flags */ - hdrflags = ntohs(*(__be16*)ptr); - - /* Trace packet contents, if enabled */ - if (tunnel->debug & PPPOL2TP_MSG_DATA) { - length = min(16u, skb->len); - if (!pskb_may_pull(skb, length)) - goto error; - - printk(KERN_DEBUG "%s: recv: ", tunnel->name); - - offset = 0; - do { - printk(" %02X", ptr[offset]); - } while (++offset < length); - - printk("\n"); - } - - /* Get length of L2TP packet */ - length = skb->len; - - /* If type is control packet, it is handled by userspace. */ - if (hdrflags & L2TP_HDRFLAG_T) { - PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG, - "%s: recv control packet, len=%d\n", tunnel->name, length); - goto error; - } - - /* Skip flags */ - ptr += 2; - - /* If length is present, skip it */ - if (hdrflags & L2TP_HDRFLAG_L) - ptr += 2; - - /* Extract tunnel and session ID */ - tunnel_id = ntohs(*(__be16 *) ptr); - ptr += 2; - session_id = ntohs(*(__be16 *) ptr); - ptr += 2; - - /* Find the session context */ - session = pppol2tp_session_find(tunnel, session_id); - if (!session) { - /* Not found? Pass to userspace to deal with */ - PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO, - "%s: no socket found (%hu/%hu). Passing up.\n", - tunnel->name, tunnel_id, session_id); - goto error; - } - sock_hold(session->sock); - - /* The ref count on the socket was increased by the above call since - * we now hold a pointer to the session. Take care to do sock_put() - * when exiting this function from now on... - */ - - /* Handle the optional sequence numbers. If we are the LAC, - * enable/disable sequence numbers under the control of the LNS. If - * no sequence numbers present but we were expecting them, discard - * frame. - */ - if (hdrflags & L2TP_HDRFLAG_S) { - u16 ns, nr; - ns = ntohs(*(__be16 *) ptr); - ptr += 2; - nr = ntohs(*(__be16 *) ptr); - ptr += 2; - - /* Received a packet with sequence numbers. If we're the LNS, - * check if we sre sending sequence numbers and if not, - * configure it so. - */ - if ((!session->lns_mode) && (!session->send_seq)) { - PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO, - "%s: requested to enable seq numbers by LNS\n", - session->name); - session->send_seq = -1; - } - - /* Store L2TP info in the skb */ - PPPOL2TP_SKB_CB(skb)->ns = ns; - PPPOL2TP_SKB_CB(skb)->nr = nr; - PPPOL2TP_SKB_CB(skb)->has_seq = 1; - - PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG, - "%s: recv data ns=%hu, nr=%hu, session nr=%hu\n", - session->name, ns, nr, session->nr); - } else { - /* No sequence numbers. - * If user has configured mandatory sequence numbers, discard. - */ - if (session->recv_seq) { - PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING, - "%s: recv data has no seq numbers when required. " - "Discarding\n", session->name); - session->stats.rx_seq_discards++; - goto discard; - } - - /* If we're the LAC and we're sending sequence numbers, the - * LNS has requested that we no longer send sequence numbers. - * If we're the LNS and we're sending sequence numbers, the - * LAC is broken. Discard the frame. - */ - if ((!session->lns_mode) && (session->send_seq)) { - PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO, - "%s: requested to disable seq numbers by LNS\n", - session->name); - session->send_seq = 0; - } else if (session->send_seq) { - PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING, - "%s: recv data has no seq numbers when required. " - "Discarding\n", session->name); - session->stats.rx_seq_discards++; - goto discard; - } - - /* Store L2TP info in the skb */ - PPPOL2TP_SKB_CB(skb)->has_seq = 0; - } - - /* If offset bit set, skip it. */ - if (hdrflags & L2TP_HDRFLAG_O) { - offset = ntohs(*(__be16 *)ptr); - ptr += 2 + offset; - } - - offset = ptr - optr; - if (!pskb_may_pull(skb, offset)) - goto discard; - - __skb_pull(skb, offset); - - /* Skip PPP header, if present. In testing, Microsoft L2TP clients - * don't send the PPP header (PPP header compression enabled), but - * other clients can include the header. So we cope with both cases - * here. The PPP header is always FF03 when using L2TP. - * - * Note that skb->data[] isn't dereferenced from a u16 ptr here since - * the field may be unaligned. - */ - if (!pskb_may_pull(skb, 2)) - goto discard; - - if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03)) - skb_pull(skb, 2); - - /* Prepare skb for adding to the session's reorder_q. Hold - * packets for max reorder_timeout or 1 second if not - * reordering. - */ - PPPOL2TP_SKB_CB(skb)->length = length; - PPPOL2TP_SKB_CB(skb)->expires = jiffies + - (session->reorder_timeout ? session->reorder_timeout : HZ); - - /* Add packet to the session's receive queue. Reordering is done here, if - * enabled. Saved L2TP protocol info is stored in skb->sb[]. - */ - if (PPPOL2TP_SKB_CB(skb)->has_seq) { - if (session->reorder_timeout != 0) { - /* Packet reordering enabled. Add skb to session's - * reorder queue, in order of ns. - */ - pppol2tp_recv_queue_skb(session, skb); - } else { - /* Packet reordering disabled. Discard out-of-sequence - * packets - */ - if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) { - session->stats.rx_seq_discards++; - PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG, - "%s: oos pkt %hu len %d discarded, " - "waiting for %hu, reorder_q_len=%d\n", - session->name, PPPOL2TP_SKB_CB(skb)->ns, - PPPOL2TP_SKB_CB(skb)->length, session->nr, - skb_queue_len(&session->reorder_q)); - goto discard; - } - skb_queue_tail(&session->reorder_q, skb); - } - } else { - /* No sequence numbers. Add the skb to the tail of the - * reorder queue. This ensures that it will be - * delivered after all previous sequenced skbs. - */ - skb_queue_tail(&session->reorder_q, skb); - } - - /* Try to dequeue as many skbs from reorder_q as we can. */ - pppol2tp_recv_dequeue(session); - sock_put(sock); - - return 0; - -discard: - session->stats.rx_errors++; - kfree_skb(skb); - sock_put(session->sock); - sock_put(sock); - - return 0; - -discard_bad_csum: - LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name); - UDP_INC_STATS_USER(&init_net, UDP_MIB_INERRORS, 0); - tunnel->stats.rx_errors++; - kfree_skb(skb); - sock_put(sock); - - return 0; - -error: - /* Put UDP header back */ - __skb_push(skb, sizeof(struct udphdr)); - sock_put(sock); - -no_tunnel: - return 1; -} - -/* UDP encapsulation receive handler. See net/ipv4/udp.c. - * Return codes: - * 0 : success. - * <0: error - * >0: skb should be passed up to userspace as UDP. - */ -static int pppol2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) -{ - struct pppol2tp_tunnel *tunnel; - - tunnel = pppol2tp_sock_to_tunnel(sk); - if (tunnel == NULL) - goto pass_up; - - PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG, - "%s: received %d bytes\n", tunnel->name, skb->len); - - if (pppol2tp_recv_core(sk, skb)) - goto pass_up_put; - - sock_put(sk); - return 0; - -pass_up_put: - sock_put(sk); -pass_up: - return 1; -} - -/* Receive message. This is the recvmsg for the PPPoL2TP socket. - */ -static int pppol2tp_recvmsg(struct kiocb *iocb, struct socket *sock, - struct msghdr *msg, size_t len, - int flags) -{ - int err; - struct sk_buff *skb; - struct sock *sk = sock->sk; - - err = -EIO; - if (sk->sk_state & PPPOX_BOUND) - goto end; - - msg->msg_namelen = 0; - - err = 0; - skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, - flags & MSG_DONTWAIT, &err); - if (!skb) - goto end; - - if (len > skb->len) - len = skb->len; - else if (len < skb->len) - msg->msg_flags |= MSG_TRUNC; - - err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, len); - if (likely(err == 0)) - err = len; - - kfree_skb(skb); -end: - return err; -} - -/************************************************************************ - * Transmit handling - ***********************************************************************/ - -/* Tell how big L2TP headers are for a particular session. This - * depends on whether sequence numbers are being used. - */ -static inline int pppol2tp_l2tp_header_len(struct pppol2tp_session *session) -{ - if (session->send_seq) - return PPPOL2TP_L2TP_HDR_SIZE_SEQ; - - return PPPOL2TP_L2TP_HDR_SIZE_NOSEQ; -} - -/* Build an L2TP header for the session into the buffer provided. - */ -static void pppol2tp_build_l2tp_header(struct pppol2tp_session *session, - void *buf) -{ - __be16 *bufp = buf; - u16 flags = L2TP_HDR_VER; - - if (session->send_seq) - flags |= L2TP_HDRFLAG_S; - - /* Setup L2TP header. - * FIXME: Can this ever be unaligned? Is direct dereferencing of - * 16-bit header fields safe here for all architectures? - */ - *bufp++ = htons(flags); - *bufp++ = htons(session->tunnel_addr.d_tunnel); - *bufp++ = htons(session->tunnel_addr.d_session); - if (session->send_seq) { - *bufp++ = htons(session->ns); - *bufp++ = 0; - session->ns++; - PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG, - "%s: updated ns to %hu\n", session->name, session->ns); - } -} - -/* This is the sendmsg for the PPPoL2TP pppol2tp_session socket. We come here - * when a user application does a sendmsg() on the session socket. L2TP and - * PPP headers must be inserted into the user's data. - */ -static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m, - size_t total_len) -{ - static const unsigned char ppph[2] = { 0xff, 0x03 }; - struct sock *sk = sock->sk; - struct inet_sock *inet; - __wsum csum; - struct sk_buff *skb; - int error; - int hdr_len; - struct pppol2tp_session *session; - struct pppol2tp_tunnel *tunnel; - struct udphdr *uh; - unsigned int len; - struct sock *sk_tun; - u16 udp_len; - - error = -ENOTCONN; - if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) - goto error; - - /* Get session and tunnel contexts */ - error = -EBADF; - session = pppol2tp_sock_to_session(sk); - if (session == NULL) - goto error; - - sk_tun = session->tunnel_sock; - tunnel = pppol2tp_sock_to_tunnel(sk_tun); - if (tunnel == NULL) - goto error_put_sess; - - /* What header length is configured for this session? */ - hdr_len = pppol2tp_l2tp_header_len(session); - - /* Allocate a socket buffer */ - error = -ENOMEM; - skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) + - sizeof(struct udphdr) + hdr_len + - sizeof(ppph) + total_len, - 0, GFP_KERNEL); - if (!skb) - goto error_put_sess_tun; - - /* Reserve space for headers. */ - skb_reserve(skb, NET_SKB_PAD); - skb_reset_network_header(skb); - skb_reserve(skb, sizeof(struct iphdr)); - skb_reset_transport_header(skb); - - /* Build UDP header */ - inet = inet_sk(sk_tun); - udp_len = hdr_len + sizeof(ppph) + total_len; - uh = (struct udphdr *) skb->data; - uh->source = inet->inet_sport; - uh->dest = inet->inet_dport; - uh->len = htons(udp_len); - uh->check = 0; - skb_put(skb, sizeof(struct udphdr)); - - /* Build L2TP header */ - pppol2tp_build_l2tp_header(session, skb->data); - skb_put(skb, hdr_len); - - /* Add PPP header */ - skb->data[0] = ppph[0]; - skb->data[1] = ppph[1]; - skb_put(skb, 2); - - /* Copy user data into skb */ - error = memcpy_fromiovec(skb->data, m->msg_iov, total_len); - if (error < 0) { - kfree_skb(skb); - goto error_put_sess_tun; - } - skb_put(skb, total_len); - - /* Calculate UDP checksum if configured to do so */ - if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT) - skb->ip_summed = CHECKSUM_NONE; - else if (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM)) { - skb->ip_summed = CHECKSUM_COMPLETE; - csum = skb_checksum(skb, 0, udp_len, 0); - uh->check = csum_tcpudp_magic(inet->inet_saddr, - inet->inet_daddr, - udp_len, IPPROTO_UDP, csum); - if (uh->check == 0) - uh->check = CSUM_MANGLED_0; - } else { - skb->ip_summed = CHECKSUM_PARTIAL; - skb->csum_start = skb_transport_header(skb) - skb->head; - skb->csum_offset = offsetof(struct udphdr, check); - uh->check = ~csum_tcpudp_magic(inet->inet_saddr, - inet->inet_daddr, - udp_len, IPPROTO_UDP, 0); - } - - /* Debug */ - if (session->send_seq) - PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG, - "%s: send %Zd bytes, ns=%hu\n", session->name, - total_len, session->ns - 1); - else - PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG, - "%s: send %Zd bytes\n", session->name, total_len); - - if (session->debug & PPPOL2TP_MSG_DATA) { - int i; - unsigned char *datap = skb->data; - - printk(KERN_DEBUG "%s: xmit:", session->name); - for (i = 0; i < total_len; i++) { - printk(" %02X", *datap++); - if (i == 15) { - printk(" ..."); - break; - } - } - printk("\n"); - } - - /* Queue the packet to IP for output */ - len = skb->len; - error = ip_queue_xmit(skb, 1); - - /* Update stats */ - if (error >= 0) { - tunnel->stats.tx_packets++; - tunnel->stats.tx_bytes += len; - session->stats.tx_packets++; - session->stats.tx_bytes += len; - } else { - tunnel->stats.tx_errors++; - session->stats.tx_errors++; - } - - return error; - -error_put_sess_tun: - sock_put(session->tunnel_sock); -error_put_sess: - sock_put(sk); -error: - return error; -} - -/* Automatically called when the skb is freed. - */ -static void pppol2tp_sock_wfree(struct sk_buff *skb) -{ - sock_put(skb->sk); -} - -/* For data skbs that we transmit, we associate with the tunnel socket - * but don't do accounting. - */ -static inline void pppol2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk) -{ - sock_hold(sk); - skb->sk = sk; - skb->destructor = pppol2tp_sock_wfree; -} - -/* Transmit function called by generic PPP driver. Sends PPP frame - * over PPPoL2TP socket. - * - * This is almost the same as pppol2tp_sendmsg(), but rather than - * being called with a msghdr from userspace, it is called with a skb - * from the kernel. - * - * The supplied skb from ppp doesn't have enough headroom for the - * insertion of L2TP, UDP and IP headers so we need to allocate more - * headroom in the skb. This will create a cloned skb. But we must be - * careful in the error case because the caller will expect to free - * the skb it supplied, not our cloned skb. So we take care to always - * leave the original skb unfreed if we return an error. - */ -static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb) -{ - static const u8 ppph[2] = { 0xff, 0x03 }; - struct sock *sk = (struct sock *) chan->private; - struct sock *sk_tun; - int hdr_len; - u16 udp_len; - struct pppol2tp_session *session; - struct pppol2tp_tunnel *tunnel; - int rc; - int headroom; - int data_len = skb->len; - struct inet_sock *inet; - __wsum csum; - struct udphdr *uh; - unsigned int len; - int old_headroom; - int new_headroom; - - if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) - goto abort; - - /* Get session and tunnel contexts from the socket */ - session = pppol2tp_sock_to_session(sk); - if (session == NULL) - goto abort; - - sk_tun = session->tunnel_sock; - if (sk_tun == NULL) - goto abort_put_sess; - tunnel = pppol2tp_sock_to_tunnel(sk_tun); - if (tunnel == NULL) - goto abort_put_sess; - - /* What header length is configured for this session? */ - hdr_len = pppol2tp_l2tp_header_len(session); - - /* Check that there's enough headroom in the skb to insert IP, - * UDP and L2TP and PPP headers. If not enough, expand it to - * make room. Adjust truesize. - */ - headroom = NET_SKB_PAD + sizeof(struct iphdr) + - sizeof(struct udphdr) + hdr_len + sizeof(ppph); - old_headroom = skb_headroom(skb); - if (skb_cow_head(skb, headroom)) - goto abort_put_sess_tun; - - new_headroom = skb_headroom(skb); - skb_orphan(skb); - skb->truesize += new_headroom - old_headroom; - - /* Setup PPP header */ - __skb_push(skb, sizeof(ppph)); - skb->data[0] = ppph[0]; - skb->data[1] = ppph[1]; - - /* Setup L2TP header */ - pppol2tp_build_l2tp_header(session, __skb_push(skb, hdr_len)); - - udp_len = sizeof(struct udphdr) + hdr_len + sizeof(ppph) + data_len; - - /* Setup UDP header */ - inet = inet_sk(sk_tun); - __skb_push(skb, sizeof(*uh)); - skb_reset_transport_header(skb); - uh = udp_hdr(skb); - uh->source = inet->inet_sport; - uh->dest = inet->inet_dport; - uh->len = htons(udp_len); - uh->check = 0; - - /* Debug */ - if (session->send_seq) |