diff options
Diffstat (limited to 'net/l2tp')
| -rw-r--r-- | net/l2tp/Makefile | 5 | ||||
| -rw-r--r-- | net/l2tp/pppol2tp.c | 2680 |
2 files changed, 2685 insertions, 0 deletions
diff --git a/net/l2tp/Makefile b/net/l2tp/Makefile new file mode 100644 index 000000000000..9af41e898a04 --- /dev/null +++ b/net/l2tp/Makefile @@ -0,0 +1,5 @@ +# +# Makefile for the L2TP. +# + +obj-$(CONFIG_PPPOL2TP) += pppol2tp.o diff --git a/net/l2tp/pppol2tp.c b/net/l2tp/pppol2tp.c new file mode 100644 index 000000000000..449a9825200d --- /dev/null +++ b/net/l2tp/pppol2tp.c @@ -0,0 +1,2680 @@ +/***************************************************************************** + * 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) + PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG, + "%s: send %d bytes, ns=%hu\n", session->name, + data_len, session->ns - 1); + else + PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG, + "%s: send %d bytes\n", session->name, data_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 < data_len; i++) { + printk(" %02X", *datap++); + if (i == 31) { + printk(" ..."); + break; + } + } + printk("\n"); + } + + memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); + IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | + IPSKB_REROUTED); + nf_reset(skb); + + /* Get routing info from the tunnel socket */ + skb_dst_drop(skb); + skb_dst_set(skb, dst_clone(__sk_dst_get(sk_tun))); + pppol2tp_skb_set_owner_w(skb, sk_tun); + + /* 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) && skb_dst(skb)->dev) && + (!(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); + } + + /* Queue the packet to IP for output */ + len = skb->len; + rc = ip_queue_xmit(skb, 1); + + /* Update stats */ + if (rc >= 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++; + } + + sock_put(sk_tun); + sock_put(sk); + return 1; + +abort_put_sess_tun: + sock_put(sk_tun); +abort_put_sess: + sock_put(sk); +abort: + /* Free the original skb */ + kfree_skb(skb); + return 1; +} + +/***************************************************************************** + * Session (and tunnel control) socket create/destroy. + *****************************************************************************/ + +/* When the tunnel UDP socket is closed, all the attached sockets need to go + * too. + */ +static void pppol2tp_tunnel_closeall(struct pppol2tp_tunnel *tunnel) +{ + int hash; + struct hlist_node *walk; + struct hlist_node *tmp; + struct pppol2tp_session *session; + struct sock *sk; + + BUG_ON(tunnel == NULL); + + PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: closing all sessions...\n", tunnel->name); + + write_lock_bh(&tunnel->hlist_lock); + for (hash = 0; hash < PPPOL2TP_HASH_SIZE; hash++) { +again: + hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) { + struct sk_buff *skb; + + session = hlist_entry(walk, struct pppol2tp_session, hlist); + + sk = session->sock; + + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: closing session\n", session->name); + + hlist_del_init(&session->hlist); + + /* Since we should hold the sock lock while + * doing any unbinding, we need to release the + * lock we're holding before taking that lock. + * Hold a reference to the sock so it doesn't + * disappear as we're jumping between locks. + */ + sock_hold(sk); + write_unlock_bh(&tunnel->hlist_lock); + lock_sock(sk); + + if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) { + pppox_unbind_sock(sk); + sk->sk_state = PPPOX_DEAD; + sk->sk_state_change(sk); + } + + /* Purge any queued data */ + skb_queue_purge(&sk->sk_receive_queue); + skb_queue_purge(&sk->sk_write_queue); + while ((skb = skb_dequeue(&session->reorder_q))) { + kfree_skb(skb); + sock_put(sk); + } + + release_sock(sk); + sock_put(sk); + + /* Now restart from the beginning of this hash + * chain. We always remove a session from the + * list so we are guaranteed to make forward + * progress. + */ + write_lock_bh(&tunnel->hlist_lock); + goto again; + } + } + write_unlock_bh(&tunnel->hlist_lock); +} + +/* Really kill the tunnel. + * Come here only when all sessions have been cleared from the tunnel. + */ +static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel) +{ + struct pppol2tp_net *pn = pppol2tp_pernet(tunnel->pppol2tp_net); + + /* Remove from socket list */ + write_lock_bh(&pn->pppol2tp_tunnel_list_lock); + list_del_init(&tunnel->list); + write_unlock_bh(&pn->pppol2tp_tunnel_list_lock); + + atomic_dec(&pppol2tp_tunnel_count); + kfree(tunnel); +} + +/* Tunnel UDP socket destruct hook. + * The tunnel context is deleted only when all session sockets have been + * closed. + */ +static void pppol2tp_tunnel_destruct(struct sock *sk) +{ + struct pppol2tp_tunnel *tunnel; + + tunnel = sk->sk_user_data; + if (tunnel == NULL) + goto end; + + PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: closing...\n", tunnel->name); + + /* Close all sessions */ + pppol2tp_tunnel_closeall(tunnel); + + /* No longer an encapsulation socket. See net/ipv4/udp.c */ + (udp_sk(sk))->encap_type = 0; + (udp_sk(sk))->encap_rcv = NULL; + + /* Remove hooks into tunnel socket */ + tunnel->sock = NULL; + sk->sk_destruct = tunnel->old_sk_destruct; + sk->sk_user_data = NULL; + + /* Call original (UDP) socket descructor */ + if (sk->sk_destruct != NULL) + (*sk->sk_destruct)(sk); + + pppol2tp_tunnel_dec_refcount(tunnel); + +end: + return; +} + +/* Really kill the session socket. (Called from sock_put() if + * refcnt == 0.) + */ +static void pppol2tp_session_destruct(struct sock *sk) +{ + struct pppol2tp_session *session = NULL; + + if (sk->sk_user_data != NULL) { + struct pppol2tp_tunnel *tunnel; + + session = sk->sk_user_data; + if (session == NULL) + goto out; + + BUG_ON(session->magic != L2TP_SESSION_MAGIC); + + /* Don't use pppol2tp_sock_to_tunnel() here to + * get the tunnel context because the tunnel + * socket might have already been closed (its + * sk->sk_user_data will be NULL) so use the + * session's private tunnel ptr instead. + */ + tunnel = session->tunnel; + if (tunnel != NULL) { + BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); + + /* If session_id is zero, this is a null + * session context, which was created for a + * socket that is being used only to manage + * tunnels. + */ + if (session->tunnel_addr.s_session != 0) { + /* Delete the session socket from the + * hash + */ + write_lock_bh(&tunnel->hlist_lock); + hlist_del_init(&session->hlist); + write_unlock_bh(&tunnel->hlist_lock); + + atomic_dec(&pppol2tp_session_count); + } + + /* This will delete the tunnel context if this + * is the last session on the tunnel. + */ + session->tunnel = NULL; + session->tunnel_sock = NULL; + pppol2tp_tunnel_dec_refcount(tunnel); + } + } + + kfree(session); +out: + return; +} + +/* Called when the PPPoX socket (session) is closed. + */ +static int pppol2tp_release(struct socket *sock) +{ + struct sock *sk = sock->sk; + struct pppol2tp_session *session; + int error; + + if (!sk) + return 0; + + error = -EBADF; + lock_sock(sk); + if (sock_flag(sk, SOCK_DEAD) != 0) + goto error; + + pppox_unbind_sock(sk); + + /* Signal the death of the socket. */ + sk->sk_state = PPPOX_DEAD; + sock_orphan(sk); + sock->sk = NULL; + + session = pppol2tp_sock_to_session(sk); + + /* Purge any queued data */ + skb_queue_purge(&sk->sk_receive_queue); + skb_queue_purge(&sk->sk_write_queue); + if (session != NULL) { + struct sk_buff *skb; + while ((skb = skb_dequeue(&session->reorder_q))) { + kfree_skb(skb); + sock_put(sk); + } + sock_put(sk); + } + + release_sock(sk); + + /* This will delete the session context via + * pppol2tp_session_destruct() if the socket's refcnt drops to + * zero. + */ + sock_put(sk); + + return 0; + +error: + release_sock(sk); + return error; +} + +/* Internal function to prepare a tunnel (UDP) socket to have PPPoX + * sockets attached to it. + */ +static struct sock *pppol2tp_prepare_tunnel_socket(struct net *net, + int fd, u16 tunnel_id, int *error) +{ + int err; + struct socket *sock = NULL; + struct sock *sk; + struct pppol2tp_tunnel *tunnel; + struct pppol2tp_net *pn; + struct sock *ret = NULL; + + /* Get the tunnel UDP socket from the fd, which was opened by + * the userspace L2TP daemon. + */ + err = -EBADF; + sock = sockfd_lookup(fd, &err); + if (!sock) { + PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR, + "tunl %hu: sockfd_lookup(fd=%d) returned %d\n", + tunnel_id, fd, err); + goto err; + } + + sk = sock->sk; + + /* Quick sanity checks */ + err = -EPROTONOSUPPORT; + if (sk->sk_protocol != IPPROTO_UDP) { + PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR, + "tunl %hu: fd %d wrong protocol, got %d, expected %d\n", + tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP); + goto err; + } + err = -EAFNOSUPPORT; + if (sock->ops->family != AF_INET) { + PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR, + "tunl %hu: fd %d wrong family, got %d, expected %d\n", + tunnel_id, fd, sock->ops->family, AF_INET); + goto err; + } + + err = -ENOTCONN; + + /* Check if this socket has already been prepped */ + tunnel = (struct pppol2tp_tunnel *)sk->sk_user_data; + if (tunnel != NULL) { + /* User-data field already set */ + err = -EBUSY; + BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); + + /* This socket has already been prepped */ + ret = tunnel->sock; + goto out; + } + + /* This socket is available and needs prepping. Create a new tunnel + * context and init it. + */ + sk->sk_user_data = tunnel = kzalloc(sizeof(struct pppol2tp_tunnel), GFP_KERNEL); + if (sk->sk_user_data == NULL) { + err = -ENOMEM; + goto err; + } + + tunnel->magic = L2TP_TUNNEL_MAGIC; + sprintf(&tunnel->name[0], "tunl %hu", tunnel_id); + + tunnel->stats.tunnel_id = tunnel_id; + tunnel->debug = PPPOL2TP_DEFAULT_DEBUG_FLAGS; + + /* Hook on the tunnel socket destructor so that we can cleanup + * if the tunnel socket goes away. + */ + tunnel->old_sk_destruct = sk->sk_destruct; + sk->sk_destruct = pppol2tp_tunnel_destruct; + + tunnel->sock = sk; + sk->sk_allocation = GFP_ATOMIC; + + /* Misc init */ + rwlock_init(&tunnel->hlist_lock); + + /* The net we belong to */ + tunnel->pppol2tp_net = net; + pn = pppol2tp_pernet(net); + + /* Add tunnel to our list */ + INIT_LIST_HEAD(&tunnel->list); + write_lock_bh(&pn->pppol2tp_tunnel_list_lock); + list_add(&tunnel->list, &pn->pppol2tp_tunnel_list); + write_unlock_bh(&pn->pppol2tp_tunnel_list_lock); + atomic_inc(&pppol2tp_tunnel_count); + + /* Bump the reference count. The tunnel context is deleted + * only when this drops to zero. + */ + pppol2tp_tunnel_inc_refcount(tunnel); + + /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ + (udp_sk(sk))->encap_type = UDP_ENCAP_L2TPINUDP; + (udp_sk(sk))->encap_rcv = pppol2tp_udp_encap_recv; + + ret = tunnel->sock; + + *error = 0; +out: + if (sock) + sockfd_put(sock); + + return ret; + +err: + *error = err; + goto out; +} + +static struct proto pppol2tp_sk_proto = { + .name = "PPPOL2TP", + .owner = THIS_MODULE, + .obj_size = sizeof(struct pppox_sock), +}; + +/* socket() handler. Initialize a new struct sock. + */ +static int pppol2tp_create(struct net *net, struct socket *sock) +{ + int error = -ENOMEM; + struct sock *sk; + + sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto); + if (!sk) + goto out; + + sock_init_data(sock, sk); + + sock->state = SS_UNCONNECTED; + sock->ops = &pppol2tp_ops; + + sk->sk_backlog_rcv = pppol2tp_recv_core; + sk->sk_protocol = PX_PROTO_OL2TP; + sk->sk_family = PF_PPPOX; + sk->sk_state = PPPOX_NONE; + sk->sk_type = SOCK_STREAM; + sk->sk_destruct = pppol2tp_session_destruct; + + error = 0; + +out: + return error; +} + +/* connect() handler. Attach a PPPoX socket to a tunnel UDP socket + */ +static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr, + int sockaddr_len, int flags) +{ + struct sock *sk = sock->sk; + struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr; + struct pppox_sock *po = pppox_sk(sk); + struct sock *tunnel_sock = NULL; + struct pppol2tp_session *session = NULL; + struct pppol2tp_tunnel *tunnel; + struct dst_entry *dst; + int error = 0; + + lock_sock(sk); + + error = -EINVAL; + if (sp->sa_protocol != PX_PROTO_OL2TP) + goto end; + + /* Check for already bound sockets */ + error = -EBUSY; + if (sk->sk_state & PPPOX_CONNECTED) + goto end; + + /* We don't supporting rebinding anyway */ + error = -EALREADY; + if (sk->sk_user_data) + goto end; /* socket is already attached */ + + /* Don't bind if s_tunnel is 0 */ + error = -EINVAL; + if (sp->pppol2tp.s_tunnel == 0) + goto end; + + /* Special case: prepare tunnel socket if s_session and + * d_session is 0. Otherwise look up tunnel using supplied + * tunnel id. + */ + if ((sp->pppol2tp.s_session == 0) && (sp->pppol2tp.d_session == 0)) { + tunnel_sock = pppol2tp_prepare_tunnel_socket(sock_net(sk), + sp->pppol2tp.fd, + sp->pppol2tp.s_tunnel, + &error); + if (tunnel_sock == NULL) + goto end; + + sock_hold(tunnel_sock); + tunnel = tunnel_sock->sk_user_data; + } else { + tunnel = pppol2tp_tunnel_find(sock_net(sk), sp->pppol2tp.s_tunnel); + + /* Error if we can't find the tunnel */ + error = -ENOENT; + if (tunnel == NULL) + goto end; + + tunnel_sock = tunnel->sock; + } + + /* Check that this session doesn't already exist */ + error = -EEXIST; + session = pppol2tp_session_find(tunnel, sp->pppol2tp.s_session); + if (session != NULL) + goto end; + + /* Allocate and initialize a new session context. */ + session = kzalloc(sizeof(struct pppol2tp_session), GFP_KERNEL); + if (session == NULL) { + error = -ENOMEM; + goto end; + } + + skb_queue_head_init(&session->reorder_q); + + session->magic = L2TP_SESSION_MAGIC; + session->owner = current->pid; + session->sock = sk; + session->tunnel = tunnel; + session->tunnel_sock = tunnel_sock; + session->tunnel_addr = sp->pppol2tp; + sprintf(&session->name[0], "sess %hu/%hu", + session->tunnel_addr.s_tunnel, + session->tunnel_addr.s_session); + + session->stats.tunnel_id = session->tunnel_addr.s_tunnel; + session->stats.session_id = session->tunnel_addr.s_session; + + INIT_HLIST_NODE(&session->hlist); + + /* Inherit debug options from tunnel */ + session->debug = tunnel->debug; + + /* Default MTU must allow space for UDP/L2TP/PPP + * headers. + */ + session->mtu = session->mru = 1500 - PPPOL2TP_HEADER_OVERHEAD; + + /* If PMTU discovery was enabled, use the MTU that was discovered */ + dst = sk_dst_get(sk); + if (dst != NULL) { + u32 pmtu = dst_mtu(__sk_dst_get(sk)); + if (pmtu != 0) + session->mtu = session->mru = pmtu - + PPPOL2TP_HEADER_OVERHEAD; + dst_release(dst); + } + + /* Special case: if source & dest session_id == 0x0000, this socket is + * being created to manage the tunnel. Don't add the session to the + * session hash list, just set up the internal context for use by + * ioctl() and sockopt() handlers. + */ + if ((session->tunnel_addr.s_session == 0) && + (session->tunnel_addr.d_session == 0)) { + error = 0; + sk->sk_user_data = session; + goto out_no_ppp; + } + + /* Get tunnel context from the tunnel socket */ + tunnel = pppol2tp_sock_to_tunnel(tunnel_sock); + if (tunnel == NULL) { + error = -EBADF; + goto end; + } + + /* Right now, because we don't have a way to push the incoming skb's + * straight through the UDP layer, the only header we need to worry + * about is the L2TP header. This size is different depending on + * whether sequence numbers are enabled for the data channel. + */ + po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ; + + po->chan.private = sk; + po->chan.ops = &pppol2tp_chan_ops; + po->chan.mtu = session->mtu; + + error = ppp_register_net_channel(sock_net(sk), &po->chan); + if (error) + goto end_put_tun; + + /* This is how we get the session context from the socket. */ + sk->sk_user_data = session; + + /* Add session to the tunnel's hash list */ + write_lock_bh(&tunnel->hlist_lock); + hlist_add_head(&session->hlist, + pppol2tp_session_id_hash(tunnel, + session->tunnel_addr.s_session)); + write_unlock_bh(&tunnel->hlist_lock); + + atomic_inc(&pppol2tp_session_count); + +out_no_ppp: + pppol2tp_tunnel_inc_refcount(tunnel); + sk->sk_state = PPPOX_CONNECTED; + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: created\n", session->name); + +end_put_tun: + sock_put(tunnel_sock); +end: + release_sock(sk); + + if (error != 0) { + if (session) + PRINTK(session->debug, + PPPOL2TP_MSG_CONTROL, KERN_WARNING, + "%s: connect failed: %d\n", + session->name, error); + else + PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_WARNING, + "connect failed: %d\n", error); + } + + return error; +} + +/* getname() support. + */ +static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr, + int *usockaddr_len, int peer) +{ + int len = sizeof(struct sockaddr_pppol2tp); + struct sockaddr_pppol2tp sp; + int error = 0; + struct pppol2tp_session *session; + + error = -ENOTCONN; + if (sock->sk->sk_state != PPPOX_CONNECTED) + goto end; + + session = pppol2tp_sock_to_session(sock->sk); + if (session == NULL) { + error = -EBADF; + goto end; + } + + sp.sa_family = AF_PPPOX; + sp.sa_protocol = PX_PROTO_OL2TP; + memcpy(&sp.pppol2tp, &session->tunnel_addr, + sizeof(struct pppol2tp_addr)); + + memcpy(uaddr, &sp, len); + + *usockaddr_len = len; + + error = 0; + sock_put(sock->sk); + +end: + return error; +} + +/**************************************************************************** + * ioctl() handlers. + * + * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP + * sockets. However, in order to control kernel tunnel features, we allow + * userspace to create a special "tunnel" PPPoX socket which is used for + * control only. Tunnel PPPoX sockets have session_id == 0 and simply allow + * the user application to issue L2TP setsockopt(), getsockopt() and ioctl() + * calls. + ****************************************************************************/ + +/* Session ioctl helper. + */ +static int pppol2tp_session_ioctl(struct pppol2tp_session *session, + unsigned int cmd, unsigned long arg) +{ + struct ifreq ifr; + int err = 0; + struct sock *sk = session->sock; + int val = (int) arg; + + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG, + "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n", + session->name, cmd, arg); + + sock_hold(sk); + + switch (cmd) { + case SIOCGIFMTU: + err = -ENXIO; + if (!(sk->sk_state & PPPOX_CONNECTED)) + break; + + err = -EFAULT; + if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq))) + break; + ifr.ifr_mtu = session->mtu; + if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq))) + break; + + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: get mtu=%d\n", session->name, session->mtu); + err = 0; + break; + + case SIOCSIFMTU: + err = -ENXIO; + if (!(sk->sk_state & PPPOX_CONNECTED)) + break; + + err = -EFAULT; + if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq))) + break; + + session->mtu = ifr.ifr_mtu; + + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: set mtu=%d\n", session->name, session->mtu); + err = 0; + break; + + case PPPIOCGMRU: + err = -ENXIO; + if (!(sk->sk_state & PPPOX_CONNECTED)) + break; + + err = -EFAULT; + if (put_user(session->mru, (int __user *) arg)) + break; + + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: get mru=%d\n", session->name, session->mru); + err = 0; + break; + + case PPPIOCSMRU: + err = -ENXIO; + if (!(sk->sk_state & PPPOX_CONNECTED)) + break; + + err = -EFAULT; + if (get_user(val,(int __user *) arg)) + break; + + session->mru = val; + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: set mru=%d\n", session->name, session->mru); + err = 0; + break; + + case PPPIOCGFLAGS: + err = -EFAULT; + if (put_user(session->flags, (int __user *) arg)) + break; + + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: get flags=%d\n", session->name, session->flags); + err = 0; + break; + + case PPPIOCSFLAGS: + err = -EFAULT; + if (get_user(val, (int __user *) arg)) + break; + session->flags = val; + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: set flags=%d\n", session->name, session->flags); + err = 0; + break; + + case PPPIOCGL2TPSTATS: + err = -ENXIO; + if (!(sk->sk_state & PPPOX_CONNECTED)) + break; + + if (copy_to_user((void __user *) arg, &session->stats, + sizeof(session->stats))) + break; + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: get L2TP stats\n", session->name); + err = 0; + break; + + default: + err = -ENOSYS; + break; + } + + sock_put(sk); + + return err; +} + +/* Tunnel ioctl helper. + * + * Note the special handling for PPPIOCGL2TPSTATS below. If the ioctl data + * specifies a session_id, the session ioctl handler is called. This allows an + * application to retrieve session stats via a tunnel socket. + */ +static int pppol2tp_tunnel_ioctl(struct pppol2tp_tunnel *tunnel, + unsigned int cmd, unsigned long arg) +{ + int err = 0; + struct sock *sk = tunnel->sock; + struct pppol2tp_ioc_stats stats_req; + + PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG, + "%s: pppol2tp_tunnel_ioctl(cmd=%#x, arg=%#lx)\n", tunnel->name, + cmd, arg); + + sock_hold(sk); + + switch (cmd) { + case PPPIOCGL2TPSTATS: + err = -ENXIO; + if (!(sk->sk_state & PPPOX_CONNECTED)) + break; + + if (copy_from_user(&stats_req, (void __user *) arg, + sizeof(stats_req))) { + err = -EFAULT; + break; + } + if (stats_req.session_id != 0) { + /* resend to session ioctl handler */ + struct pppol2tp_session *session = + pppol2tp_session_find(tunnel, stats_req.session_id); + if (session != NULL) + err = pppol2tp_session_ioctl(session, cmd, arg); + else + err = -EBADR; + break; + } +#ifdef CONFIG_XFRM + tunnel->stats.using_ipsec = (sk->sk_policy[0] || sk->sk_policy[1]) ? 1 : 0; +#endif + if (copy_to_user((void __user *) arg, &tunnel->stats, + sizeof(tunnel->stats))) { + err = -EFAULT; + break; + } + PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: get L2TP stats\n", tunnel->name); + err = 0; + break; + + default: + err = -ENOSYS; + break; + } + + sock_put(sk); + + return err; +} + +/* Main ioctl() handler. + * Dispatch to tunnel or session helpers depending on the socket. + */ +static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd, + unsigned long arg) +{ + struct sock *sk = sock->sk; + struct pppol2tp_session *session; + struct pppol2tp_tunnel *tunnel; + int err; + + if (!sk) + return 0; + + err = -EBADF; + if (sock_flag(sk, SOCK_DEAD) != 0) + goto end; + + err = -ENOTCONN; + if ((sk->sk_user_data == NULL) || + (!(sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)))) + goto end; + + /* Get session context from the socket */ + err = -EBADF; + session = pppol2tp_sock_to_session(sk); + if (session == NULL) + goto end; + + /* Special case: if session's session_id is zero, treat ioctl as a + * tunnel ioctl + */ + if ((session->tunnel_addr.s_session == 0) && + (session->tunnel_addr.d_session == 0)) { + err = -EBADF; + tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock); + if (tunnel == NULL) + goto end_put_sess; + + err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg); + sock_put(session->tunnel_sock); + goto end_put_sess; + } + + err = pppol2tp_session_ioctl(session, cmd, arg); + +end_put_sess: + sock_put(sk); +end: + return err; +} + +/***************************************************************************** + * setsockopt() / getsockopt() support. + * + * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP + * sockets. In order to control kernel tunnel features, we allow userspace to + * create a special "tunnel" PPPoX socket which is used for control only. + * Tunnel PPPoX sockets have session_id == 0 and simply allow the user + * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls. + *****************************************************************************/ + +/* Tunnel setsockopt() helper. + */ +static int pppol2tp_tunnel_setsockopt(struct sock *sk, + struct pppol2tp_tunnel *tunnel, + int optname, int val) +{ + int err = 0; + + switch (optname) { + case PPPOL2TP_SO_DEBUG: + tunnel->debug = val; + PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: set debug=%x\n", tunnel->name, tunnel->debug); + break; + + default: + err = -ENOPROTOOPT; + break; + } + + return err; +} + +/* Session setsockopt helper. + */ +static int pppol2tp_session_setsockopt(struct sock *sk, + struct pppol2tp_session *session, + int optname, int val) +{ + int err = 0; + + switch (optname) { + case PPPOL2TP_SO_RECVSEQ: + if ((val != 0) && (val != 1)) { + err = -EINVAL; + break; + } + session->recv_seq = val ? -1 : 0; + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: set recv_seq=%d\n", session->name, + session->recv_seq); + break; + + case PPPOL2TP_SO_SENDSEQ: + if ((val != 0) && (val != 1)) { + err = -EINVAL; + break; + } + session->send_seq = val ? -1 : 0; + { + struct sock *ssk = session->sock; + struct pppox_sock *po = pppox_sk(ssk); + po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ : + PPPOL2TP_L2TP_HDR_SIZE_NOSEQ; + } + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: set send_seq=%d\n", session->name, session->send_seq); + break; + + case PPPOL2TP_SO_LNSMODE: + if ((val != 0) && (val != 1)) { + err = -EINVAL; + break; + } + session->lns_mode = val ? -1 : 0; + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: set lns_mode=%d\n", session->name, + session->lns_mode); + break; + + case PPPOL2TP_SO_DEBUG: + session->debug = val; + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: set debug=%x\n", session->name, session->debug); + break; + + case PPPOL2TP_SO_REORDERTO: + session->reorder_timeout = msecs_to_jiffies(val); + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: set reorder_timeout=%d\n", session->name, + session->reorder_timeout); + break; + + default: + err = -ENOPROTOOPT; + break; + } + + return err; +} + +/* Main setsockopt() entry point. + * Does API checks, then calls either the tunnel or session setsockopt + * handler, according to whether the PPPoL2TP socket is a for a regular + * session or the special tunnel type. + */ +static int pppol2tp_setsockopt(struct socket *sock, int level, int optname, + char __user *optval, unsigned int optlen) +{ + struct sock *sk = sock->sk; + struct pppol2tp_session *session = sk->sk_user_data; + struct pppol2tp_tunnel *tunnel; + int val; + int err; + + if (level != SOL_PPPOL2TP) + return udp_prot.setsockopt(sk, level, optname, optval, optlen); + + if (optlen < sizeof(int)) + return -EINVAL; + + if (get_user(val, (int __user *)optval)) + return -EFAULT; + + err = -ENOTCONN; + if (sk->sk_user_data == NULL) + goto end; + + /* Get session context from the socket */ + err = -EBADF; + session = pppol2tp_sock_to_session(sk); + if (session == NULL) + goto end; + + /* Special case: if session_id == 0x0000, treat as operation on tunnel + */ + if ((session->tunnel_addr.s_session == 0) && + (session->tunnel_addr.d_session == 0)) { + err = -EBADF; + tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock); + if (tunnel == NULL) + goto end_put_sess; + + err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val); + sock_put(session->tunnel_sock); + } else + err = pppol2tp_session_setsockopt(sk, session, optname, val); + + err = 0; + +end_put_sess: + sock_put(sk); +end: + return err; +} + +/* Tunnel getsockopt helper. Called with sock locked. + */ +static int pppol2tp_tunnel_getsockopt(struct sock *sk, + struct pppol2tp_tunnel *tunnel, + int optname, int *val) +{ + int err = 0; + + switch (optname) { + case PPPOL2TP_SO_DEBUG: + *val = tunnel->debug; + PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: get debug=%x\n", tunnel->name, tunnel->debug); + break; + + default: + err = -ENOPROTOOPT; + break; + } + + return err; +} + +/* Session getsockopt helper. Called with sock locked. + */ +static int pppol2tp_session_getsockopt(struct sock *sk, + struct pppol2tp_session *session, + int optname, int *val) +{ + int err = 0; + + switch (optname) { + case PPPOL2TP_SO_RECVSEQ: + *val = session->recv_seq; + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: get recv_seq=%d\n", session->name, *val); + break; + + case PPPOL2TP_SO_SENDSEQ: + *val = session->send_seq; + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: get send_seq=%d\n", session->name, *val); + break; + + case PPPOL2TP_SO_LNSMODE: + *val = session->lns_mode; + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: get lns_mode=%d\n", session->name, *val); + break; + + case PPPOL2TP_SO_DEBUG: + *val = session->debug; + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: get debug=%d\n", session->name, *val); + break; + + case PPPOL2TP_SO_REORDERTO: + *val = (int) jiffies_to_msecs(session->reorder_timeout); + PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO, + "%s: get reorder_timeout=%d\n", session->name, *val); + break; + + default: + err = -ENOPROTOOPT; + } + + return err; +} + +/* Main getsockopt() entry point. + * Does API checks, then calls either the tunnel or session getsockopt + * handler, according to whether the PPPoX socket is a for a regular session + * or the special tunnel type. + */ +static int pppol2tp_getsockopt(struct socket *sock, int level, + int optname, char __user *optval, int __user *optlen) +{ + struct sock *sk = sock->sk; + struct pppol2tp_session *session = sk->sk_user_data; + struct pppol2tp_tunnel *tunnel; + int val, len; + int err; + + if (level != SOL_PPPOL2TP) + return udp_prot.getsockopt(sk, level, optname, optval, optlen); + + if (get_user(len, (int __user *) optlen)) + return -EFAULT; + + len = min_t(unsigned int, len, sizeof(int)); + + if (len < 0) + return -EINVAL; + + err = -ENOTCONN; + if (sk->sk_user_data == NULL) + goto end; + + /* Get the session context */ + err = -EBADF; + session = pppol2tp_sock_to_session(sk); + if (session == NULL) + goto end; + + /* Special case: if session_id == 0x0000, treat as operation on tunnel */ + if ((session->tunnel_addr.s_session == 0) && + (session->tunnel_addr.d_session == 0)) { + err = -EBADF; + tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock); + if (tunnel == NULL) + goto end_put_sess; + + err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val); + sock_put(session->tunnel_sock); + } else + err = pppol2tp_session_getsockopt(sk, session, optname, &val); + + err = -EFAULT; + if (put_user(len, (int __user *) optlen)) + goto end_put_sess; + + if (copy_to_user((void __user *) optval, &val, len)) + goto end_put_sess; + + err = 0; + +end_put_sess: + sock_put(sk); +end: + return err; +} + +/***************************************************************************** + * /proc filesystem for debug + *****************************************************************************/ + +#ifdef CONFIG_PROC_FS + +#include <linux/seq_file.h> + +struct pppol2tp_seq_data { + struct seq_net_private p; + struct pppol2tp_tunnel *tunnel; /* current tunnel */ + struct pppol2tp_session *session; /* NULL means get first session in tunnel */ +}; + +static struct pppol2tp_session *next_session(struct pppol2tp_tunnel *tunnel, struct pppol2tp_session *curr) +{ + struct pppol2tp_session *session = NULL; + struct hlist_node *walk; + int found = 0; + int next = 0; + int i; + + read_lock_bh(&tunnel->hlist_lock); + for (i = 0; i < PPPOL2TP_HASH_SIZE; i++) { + hlist_for_each_entry(session, walk, &tunnel->session_hlist[i], hlist) { + if (curr == NULL) { + found = 1; + goto out; + } + if (session == curr) { + next = 1; + continue; + } + if (next) { + found = 1; + goto out; + } + } + } +out: + read_unlock_bh(&tunnel->hlist_lock); + if (!found) + session = NULL; + + return session; +} + +static struct pppol2tp_tunnel *next_tunnel(struct pppol2tp_net *pn, + struct pppol2tp_tunnel *curr) +{ + struct pppol2tp_tunnel *tunnel = NULL; + + read_lock_bh(&pn->pppol2tp_tunnel_list_lock); + if (list_is_last(&curr->list, &pn->pppol2tp_tunnel_list)) { + goto out; + } + tunnel = list_entry(curr->list.next, struct pppol2tp_tunnel, list); +out: + read_unlock_bh(&pn->pppol2tp_tunnel_list_lock); + + return tunnel; +} + +static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs) +{ + struct pppol2tp_seq_data *pd = SEQ_START_TOKEN; + struct pppol2tp_net *pn; + loff_t pos = *offs; + + if (!pos) + goto out; + + BUG_ON(m->private == NULL); + pd = m->private; + pn = pppol2tp_pernet(seq_file_net(m)); + + if (pd->tunnel == NULL) { + if (!list_empty(&pn->pppol2tp_tunnel_list)) + pd->tunnel = list_entry(pn->pppol2tp_tunnel_list.next, struct pppol2tp_tunnel, list); + } else { + pd->session = next_session(pd->tunnel, pd->session); + if (pd->session == NULL) { + pd->tunnel = next_tunnel(pn, pd->tunnel); + } + } + + /* NULL tunnel and session indicates end of list */ + if ((pd->tunnel == NULL) && (pd->session == NULL)) + pd = NULL; + +out: + return pd; +} + +static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos) +{ + (*pos)++; + return NULL; +} + +static void pppol2tp_seq_stop(struct seq_file *p, void *v) +{ + /* nothing to do */ +} + +static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v) +{ + struct pppol2tp_tunnel *tunnel = v; + + seq_printf(m, "\nTUNNEL '%s', %c %d\n", + tunnel->name, + (tunnel == tunnel->sock->sk_user_data) ? 'Y':'N', + atomic_read(&tunnel->ref_count) - 1); + seq_printf(m, " %08x %llu/%llu/%llu %llu/%llu/%llu\n", + tunnel->debug, + (unsigned long long)tunnel->stats.tx_packets, + (unsigned long long)tunnel->stats.tx_bytes, + (unsigned long long)tunnel->stats.tx_errors, + (unsigned long long)tunnel->stats.rx_packets, + (unsigned long long)tunnel->stats.rx_bytes, + (unsigned long long)tunnel->stats.rx_errors); +} + +static void pppol2tp_seq_session_show(struct seq_file *m, void *v) +{ + struct pppol2tp_session *session = v; + + seq_printf(m, " SESSION '%s' %08X/%d %04X/%04X -> " + "%04X/%04X %d %c\n", + session->name, + ntohl(session->tunnel_addr.addr.sin_addr.s_addr), + ntohs(session->tunnel_addr.addr.sin_port), + session->tunnel_addr.s_tunnel, + session->tunnel_addr.s_session, + session->tunnel_addr.d_tunnel, + session->tunnel_addr.d_session, + session->sock->sk_state, + (session == session->sock->sk_user_data) ? + 'Y' : 'N'); + seq_printf(m, " %d/%d/%c/%c/%s %08x %u\n", + session->mtu, session->mru, + session->recv_seq ? 'R' : '-', + session->send_seq ? 'S' : '-', + session->lns_mode ? "LNS" : "LAC", + session->debug, + jiffies_to_msecs(session->reorder_timeout)); + seq_printf(m, " %hu/%hu %llu/%llu/%llu %llu/%llu/%llu\n", + session->nr, session->ns, + (unsigned long long)session->stats.tx_packets, + (unsigned long long)session->stats.tx_bytes, + (unsigned long long)session->stats.tx_errors, + (unsigned long long)session->stats.rx_packets, + (unsigned long long)session->stats.rx_bytes, + (unsigned long long)session->stats.rx_errors); +} + +static int pppol2tp_seq_show(struct seq_file *m, void *v) +{ + struct pppol2tp_seq_data *pd = v; + + /* display header on line 1 */ + if (v == SEQ_START_TOKEN) { + seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n"); + seq_puts(m, "TUNNEL name, user-data-ok session-count\n"); + seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n"); + seq_puts(m, " SESSION name, addr/port src-tid/sid " + "dest-tid/sid state user-data-ok\n"); + seq_puts(m, " mtu/mru/rcvseq/sendseq/lns debug reorderto\n"); + seq_puts(m, " nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n"); + goto out; + } + + /* Show the tunnel or session context. + */ + if (pd->session == NULL) + pppol2tp_seq_tunnel_show(m, pd->tunnel); + else + pppol2tp_seq_session_show(m, pd->session); + +out: + return 0; +} + +static const struct seq_operations pppol2tp_seq_ops = { + .start = pppol2tp_seq_start, + .next = pppol2tp_seq_next, + .stop = pppol2tp_seq_stop, + .show = pppol2tp_seq_show, +}; + +/* Called when our /proc file is opened. We allocate data for use when + * iterating our tunnel / session contexts and store it in the private + * data of the seq_file. + */ +static int pppol2tp_proc_open(struct inode *inode, struct file *file) +{ + return seq_open_net(inode, file, &pppol2tp_seq_ops, + sizeof(struct pppol2tp_seq_data)); +} + +static const struct file_operations pppol2tp_proc_fops = { + .owner = THIS_MODULE, + .open = pppol2tp_proc_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_net, +}; + +#endif /* CONFIG_PROC_FS */ + +/***************************************************************************** + * Init and cleanup + *****************************************************************************/ + +static const struct proto_ops pppol2tp_ops = { + .family = AF_PPPOX, + .owner = THIS_MODULE, + .release = pppol2tp_release, + .bind = sock_no_bind, + .connect = pppol2tp_connect, + .socketpair = sock_no_socketpair, + .accept = sock_no_accept, + .getname = pppol2tp_getname, + .poll = datagram_poll, + .listen = sock_no_listen, + .shutdown = sock_no_shutdown, + .setsockopt = pppol2tp_setsockopt, + .getsockopt = pppol2tp_getsockopt, + .sendmsg = pppol2tp_sendmsg, + .recvmsg = pppol2tp_recvmsg, + .mmap = sock_no_mmap, + .ioctl = pppox_ioctl, +}; + +static struct pppox_proto pppol2tp_proto = { + .create = pppol2tp_create, + .ioctl = pppol2tp_ioctl +}; + +static __net_init int pppol2tp_init_net(struct net *net) +{ + struct pppol2tp_net *pn = pppol2tp_pernet(net); + struct proc_dir_entry *pde; + + INIT_LIST_HEAD(&pn->pppol2tp_tunnel_list); + rwlock_init(&pn->pppol2tp_tunnel_list_lock); + + pde = proc_net_fops_create(net, "pppol2tp", S_IRUGO, &pppol2tp_proc_fops); +#ifdef CONFIG_PROC_FS + if (!pde) + return -ENOMEM; +#endif + + return 0; +} + +static __net_exit void pppol2tp_exit_net(struct net *net) +{ + proc_net_remove(net, "pppol2tp"); +} + +static struct pernet_operations pppol2tp_net_ops = { + .init = pppol2tp_init_net, + .exit = pppol2tp_exit_net, + .id = &pppol2tp_net_id, + .size = sizeof(struct pppol2tp_net), +}; + +static int __init pppol2tp_init(void) +{ + int err; + + err = proto_register(&pppol2tp_sk_proto, 0); + if (err) + goto out; + err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto); + if (err) + goto out_unregister_pppol2tp_proto; + + err = register_pernet_device(&pppol2tp_net_ops); + if (err) + goto out_unregister_pppox_proto; + + printk(KERN_INFO "PPPoL2TP kernel driver, %s\n", + PPPOL2TP_DRV_VERSION); + +out: + return err; +out_unregister_pppox_proto: + unregister_pppox_proto(PX_PROTO_OL2TP); +out_unregister_pppol2tp_proto: + proto_unregister(&pppol2tp_sk_proto); + goto out; +} + +static void __exit pppol2tp_exit(void) +{ + unregister_pppox_proto(PX_PROTO_OL2TP); + unregister_pernet_device(&pppol2tp_net_ops); + proto_unregister(&pppol2tp_sk_proto); +} + +module_init(pppol2tp_init); +module_exit(pppol2tp_exit); + +MODULE_AUTHOR("Martijn van Oosterhout <kleptog@svana.org>, " + "James Chapman <jchapman@katalix.com>"); +MODULE_DESCRIPTION("PPP over L2TP over UDP"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(PPPOL2TP_DRV_VERSION); |