| /* |
| * L2TP core. |
| * |
| * Copyright (c) 2008,2009,2010 Katalix Systems Ltd |
| * |
| * This file contains some code of the original L2TPv2 pppol2tp |
| * driver, which has the following copyright: |
| * |
| * 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) |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/string.h> |
| #include <linux/list.h> |
| #include <linux/rculist.h> |
| #include <linux/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/in.h> |
| #include <linux/ip.h> |
| #include <linux/udp.h> |
| #include <linux/l2tp.h> |
| #include <linux/hash.h> |
| #include <linux/sort.h> |
| #include <linux/file.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/inet_common.h> |
| #include <net/xfrm.h> |
| #include <net/protocol.h> |
| #include <net/inet6_connection_sock.h> |
| #include <net/inet_ecn.h> |
| #include <net/ip6_route.h> |
| #include <net/ip6_checksum.h> |
| |
| #include <asm/byteorder.h> |
| #include <linux/atomic.h> |
| |
| #include "l2tp_core.h" |
| |
| #define L2TP_DRV_VERSION "V2.0" |
| |
| /* 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_2 0x0002 |
| #define L2TP_HDR_VER_3 0x0003 |
| |
| /* L2TPv3 default L2-specific sublayer */ |
| #define L2TP_SLFLAG_S 0x40000000 |
| #define L2TP_SL_SEQ_MASK 0x00ffffff |
| |
| #define L2TP_HDR_SIZE_SEQ 10 |
| #define L2TP_HDR_SIZE_NOSEQ 6 |
| |
| /* Default trace flags */ |
| #define L2TP_DEFAULT_DEBUG_FLAGS 0 |
| |
| #define PRINTK(_mask, _type, _lvl, _fmt, args...) \ |
| do { \ |
| if ((_mask) & (_type)) \ |
| printk(_lvl "L2TP: " _fmt, ##args); \ |
| } while (0) |
| |
| /* Private data stored for received packets in the skb. |
| */ |
| struct l2tp_skb_cb { |
| u32 ns; |
| u16 has_seq; |
| u16 length; |
| unsigned long expires; |
| }; |
| |
| #define L2TP_SKB_CB(skb) ((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)]) |
| |
| static atomic_t l2tp_tunnel_count; |
| static atomic_t l2tp_session_count; |
| |
| /* per-net private data for this module */ |
| static unsigned int l2tp_net_id; |
| struct l2tp_net { |
| struct list_head l2tp_tunnel_list; |
| spinlock_t l2tp_tunnel_list_lock; |
| struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2]; |
| spinlock_t l2tp_session_hlist_lock; |
| }; |
| |
| static void l2tp_session_set_header_len(struct l2tp_session *session, int version); |
| static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel); |
| static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel); |
| |
| static inline struct l2tp_net *l2tp_pernet(struct net *net) |
| { |
| BUG_ON(!net); |
| |
| return net_generic(net, l2tp_net_id); |
| } |
| |
| |
| /* Tunnel reference counts. Incremented per session that is added to |
| * the tunnel. |
| */ |
| static inline void l2tp_tunnel_inc_refcount_1(struct l2tp_tunnel *tunnel) |
| { |
| atomic_inc(&tunnel->ref_count); |
| } |
| |
| static inline void l2tp_tunnel_dec_refcount_1(struct l2tp_tunnel *tunnel) |
| { |
| if (atomic_dec_and_test(&tunnel->ref_count)) |
| l2tp_tunnel_free(tunnel); |
| } |
| #ifdef L2TP_REFCNT_DEBUG |
| #define l2tp_tunnel_inc_refcount(_t) do { \ |
| printk(KERN_DEBUG "l2tp_tunnel_inc_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \ |
| l2tp_tunnel_inc_refcount_1(_t); \ |
| } while (0) |
| #define l2tp_tunnel_dec_refcount(_t) do { \ |
| printk(KERN_DEBUG "l2tp_tunnel_dec_refcount: %s:%d %s: cnt=%d\n", __func__, __LINE__, (_t)->name, atomic_read(&_t->ref_count)); \ |
| l2tp_tunnel_dec_refcount_1(_t); \ |
| } while (0) |
| #else |
| #define l2tp_tunnel_inc_refcount(t) l2tp_tunnel_inc_refcount_1(t) |
| #define l2tp_tunnel_dec_refcount(t) l2tp_tunnel_dec_refcount_1(t) |
| #endif |
| |
| /* Session hash global list for L2TPv3. |
| * The session_id SHOULD be random according to RFC3931, but several |
| * L2TP implementations use incrementing session_ids. So we do a real |
| * hash on the session_id, rather than a simple bitmask. |
| */ |
| static inline struct hlist_head * |
| l2tp_session_id_hash_2(struct l2tp_net *pn, u32 session_id) |
| { |
| return &pn->l2tp_session_hlist[hash_32(session_id, L2TP_HASH_BITS_2)]; |
| |
| } |
| |
| /* Lookup a session by id in the global session list |
| */ |
| static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id) |
| { |
| struct l2tp_net *pn = l2tp_pernet(net); |
| struct hlist_head *session_list = |
| l2tp_session_id_hash_2(pn, session_id); |
| struct l2tp_session *session; |
| struct hlist_node *walk; |
| |
| rcu_read_lock_bh(); |
| hlist_for_each_entry_rcu(session, walk, session_list, global_hlist) { |
| if (session->session_id == session_id) { |
| rcu_read_unlock_bh(); |
| return session; |
| } |
| } |
| rcu_read_unlock_bh(); |
| |
| return NULL; |
| } |
| |
| /* 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 * |
| l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id) |
| { |
| return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)]; |
| } |
| |
| /* Lookup a session by id |
| */ |
| struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id) |
| { |
| struct hlist_head *session_list; |
| struct l2tp_session *session; |
| struct hlist_node *walk; |
| |
| /* In L2TPv3, session_ids are unique over all tunnels and we |
| * sometimes need to look them up before we know the |
| * tunnel. |
| */ |
| if (tunnel == NULL) |
| return l2tp_session_find_2(net, session_id); |
| |
| session_list = l2tp_session_id_hash(tunnel, session_id); |
| read_lock_bh(&tunnel->hlist_lock); |
| hlist_for_each_entry(session, walk, session_list, hlist) { |
| if (session->session_id == session_id) { |
| read_unlock_bh(&tunnel->hlist_lock); |
| return session; |
| } |
| } |
| read_unlock_bh(&tunnel->hlist_lock); |
| |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(l2tp_session_find); |
| |
| struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth) |
| { |
| int hash; |
| struct hlist_node *walk; |
| struct l2tp_session *session; |
| int count = 0; |
| |
| read_lock_bh(&tunnel->hlist_lock); |
| for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { |
| hlist_for_each_entry(session, walk, &tunnel->session_hlist[hash], hlist) { |
| if (++count > nth) { |
| read_unlock_bh(&tunnel->hlist_lock); |
| return session; |
| } |
| } |
| } |
| |
| read_unlock_bh(&tunnel->hlist_lock); |
| |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(l2tp_session_find_nth); |
| |
| /* Lookup a session by interface name. |
| * This is very inefficient but is only used by management interfaces. |
| */ |
| struct l2tp_session *l2tp_session_find_by_ifname(struct net *net, char *ifname) |
| { |
| struct l2tp_net *pn = l2tp_pernet(net); |
| int hash; |
| struct hlist_node *walk; |
| struct l2tp_session *session; |
| |
| rcu_read_lock_bh(); |
| for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) { |
| hlist_for_each_entry_rcu(session, walk, &pn->l2tp_session_hlist[hash], global_hlist) { |
| if (!strcmp(session->ifname, ifname)) { |
| rcu_read_unlock_bh(); |
| return session; |
| } |
| } |
| } |
| |
| rcu_read_unlock_bh(); |
| |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(l2tp_session_find_by_ifname); |
| |
| /* Lookup a tunnel by id |
| */ |
| struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id) |
| { |
| struct l2tp_tunnel *tunnel; |
| struct l2tp_net *pn = l2tp_pernet(net); |
| |
| rcu_read_lock_bh(); |
| list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { |
| if (tunnel->tunnel_id == tunnel_id) { |
| rcu_read_unlock_bh(); |
| return tunnel; |
| } |
| } |
| rcu_read_unlock_bh(); |
| |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(l2tp_tunnel_find); |
| |
| struct l2tp_tunnel *l2tp_tunnel_find_nth(struct net *net, int nth) |
| { |
| struct l2tp_net *pn = l2tp_pernet(net); |
| struct l2tp_tunnel *tunnel; |
| int count = 0; |
| |
| rcu_read_lock_bh(); |
| list_for_each_entry_rcu(tunnel, &pn->l2tp_tunnel_list, list) { |
| if (++count > nth) { |
| rcu_read_unlock_bh(); |
| return tunnel; |
| } |
| } |
| |
| rcu_read_unlock_bh(); |
| |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(l2tp_tunnel_find_nth); |
| |
| /***************************************************************************** |
| * Receive data handling |
| *****************************************************************************/ |
| |
| /* Queue a skb in order. We come here only if the skb has an L2TP sequence |
| * number. |
| */ |
| static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *skb) |
| { |
| struct sk_buff *skbp; |
| struct sk_buff *tmp; |
| u32 ns = L2TP_SKB_CB(skb)->ns; |
| struct l2tp_stats *sstats; |
| |
| spin_lock_bh(&session->reorder_q.lock); |
| sstats = &session->stats; |
| skb_queue_walk_safe(&session->reorder_q, skbp, tmp) { |
| if (L2TP_SKB_CB(skbp)->ns > ns) { |
| __skb_queue_before(&session->reorder_q, skbp, skb); |
| PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n", |
| session->name, ns, L2TP_SKB_CB(skbp)->ns, |
| skb_queue_len(&session->reorder_q)); |
| u64_stats_update_begin(&sstats->syncp); |
| sstats->rx_oos_packets++; |
| u64_stats_update_end(&sstats->syncp); |
| goto out; |
| } |
| } |
| |
| __skb_queue_tail(&session->reorder_q, skb); |
| |
| out: |
| spin_unlock_bh(&session->reorder_q.lock); |
| } |
| |
| /* Dequeue a single skb. |
| */ |
| static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *skb) |
| { |
| struct l2tp_tunnel *tunnel = session->tunnel; |
| int length = L2TP_SKB_CB(skb)->length; |
| struct l2tp_stats *tstats, *sstats; |
| |
| /* We're about to requeue the skb, so return resources |
| * to its current owner (a socket receive buffer). |
| */ |
| skb_orphan(skb); |
| |
| tstats = &tunnel->stats; |
| u64_stats_update_begin(&tstats->syncp); |
| sstats = &session->stats; |
| u64_stats_update_begin(&sstats->syncp); |
| tstats->rx_packets++; |
| tstats->rx_bytes += length; |
| sstats->rx_packets++; |
| sstats->rx_bytes += length; |
| u64_stats_update_end(&tstats->syncp); |
| u64_stats_update_end(&sstats->syncp); |
| |
| if (L2TP_SKB_CB(skb)->has_seq) { |
| /* Bump our Nr */ |
| session->nr++; |
| if (tunnel->version == L2TP_HDR_VER_2) |
| session->nr &= 0xffff; |
| else |
| session->nr &= 0xffffff; |
| |
| PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| "%s: updated nr to %hu\n", session->name, session->nr); |
| } |
| |
| /* call private receive handler */ |
| if (session->recv_skb != NULL) |
| (*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length); |
| else |
| kfree_skb(skb); |
| |
| if (session->deref) |
| (*session->deref)(session); |
| } |
| |
| /* 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 l2tp_recv_dequeue(struct l2tp_session *session) |
| { |
| struct sk_buff *skb; |
| struct sk_buff *tmp; |
| struct l2tp_stats *sstats; |
| |
| /* 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. |
| */ |
| start: |
| spin_lock_bh(&session->reorder_q.lock); |
| sstats = &session->stats; |
| skb_queue_walk_safe(&session->reorder_q, skb, tmp) { |
| if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) { |
| u64_stats_update_begin(&sstats->syncp); |
| sstats->rx_seq_discards++; |
| sstats->rx_errors++; |
| u64_stats_update_end(&sstats->syncp); |
| PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| "%s: oos pkt %u len %d discarded (too old), " |
| "waiting for %u, reorder_q_len=%d\n", |
| session->name, L2TP_SKB_CB(skb)->ns, |
| L2TP_SKB_CB(skb)->length, session->nr, |
| skb_queue_len(&session->reorder_q)); |
| session->reorder_skip = 1; |
| __skb_unlink(skb, &session->reorder_q); |
| kfree_skb(skb); |
| if (session->deref) |
| (*session->deref)(session); |
| continue; |
| } |
| |
| if (L2TP_SKB_CB(skb)->has_seq) { |
| if (session->reorder_skip) { |
| PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| "%s: advancing nr to next pkt: %u -> %u", |
| session->name, session->nr, |
| L2TP_SKB_CB(skb)->ns); |
| session->reorder_skip = 0; |
| session->nr = L2TP_SKB_CB(skb)->ns; |
| } |
| if (L2TP_SKB_CB(skb)->ns != session->nr) { |
| PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| "%s: holding oos pkt %u len %d, " |
| "waiting for %u, reorder_q_len=%d\n", |
| session->name, L2TP_SKB_CB(skb)->ns, |
| L2TP_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); |
| l2tp_recv_dequeue_skb(session, skb); |
| goto start; |
| } |
| |
| out: |
| spin_unlock_bh(&session->reorder_q.lock); |
| } |
| |
| static inline int l2tp_verify_udp_checksum(struct sock *sk, |
| struct sk_buff *skb) |
| { |
| struct udphdr *uh = udp_hdr(skb); |
| u16 ulen = ntohs(uh->len); |
| __wsum psum; |
| |
| if (sk->sk_no_check || skb_csum_unnecessary(skb)) |
| return 0; |
| |
| #if IS_ENABLED(CONFIG_IPV6) |
| if (sk->sk_family == PF_INET6) { |
| if (!uh->check) { |
| LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n"); |
| return 1; |
| } |
| if ((skb->ip_summed == CHECKSUM_COMPLETE) && |
| !csum_ipv6_magic(&ipv6_hdr(skb)->saddr, |
| &ipv6_hdr(skb)->daddr, ulen, |
| IPPROTO_UDP, skb->csum)) { |
| skb->ip_summed = CHECKSUM_UNNECESSARY; |
| return 0; |
| } |
| skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr, |
| &ipv6_hdr(skb)->daddr, |
| skb->len, IPPROTO_UDP, |
| 0)); |
| } else |
| #endif |
| { |
| struct inet_sock *inet; |
| if (!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); |
| } |
| |
| /* Do receive processing of L2TP data frames. We handle both L2TPv2 |
| * and L2TPv3 data frames here. |
| * |
| * L2TPv2 Data Message Header |
| * |
| * 0 1 2 3 |
| * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * |T|L|x|x|S|x|O|P|x|x|x|x| Ver | Length (opt) | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | Tunnel ID | Session ID | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | Ns (opt) | Nr (opt) | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | Offset Size (opt) | Offset pad... (opt) |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * |
| * Data frames are marked by T=0. All other fields are the same as |
| * those in L2TP control frames. |
| * |
| * L2TPv3 Data Message Header |
| * |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | L2TP Session Header | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | L2-Specific Sublayer | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | Tunnel Payload ... |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * |
| * L2TPv3 Session Header Over IP |
| * |
| * 0 1 2 3 |
| * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | Session ID | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | Cookie (optional, maximum 64 bits)... |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * |
| * L2TPv3 L2-Specific Sublayer Format |
| * |
| * 0 1 2 3 |
| * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * |x|S|x|x|x|x|x|x| Sequence Number | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * |
| * Cookie value, sublayer format and offset (pad) are negotiated with |
| * the peer when the session is set up. Unlike L2TPv2, we do not need |
| * to parse the packet header to determine if optional fields are |
| * present. |
| * |
| * Caller must already have parsed the frame and determined that it is |
| * a data (not control) frame before coming here. Fields up to the |
| * session-id have already been parsed and ptr points to the data |
| * after the session-id. |
| */ |
| void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb, |
| unsigned char *ptr, unsigned char *optr, u16 hdrflags, |
| int length, int (*payload_hook)(struct sk_buff *skb)) |
| { |
| struct l2tp_tunnel *tunnel = session->tunnel; |
| int offset; |
| u32 ns, nr; |
| struct l2tp_stats *sstats = &session->stats; |
| |
| /* The ref count is increased since we now hold a pointer to |
| * the session. Take care to decrement the refcnt when exiting |
| * this function from now on... |
| */ |
| l2tp_session_inc_refcount(session); |
| if (session->ref) |
| (*session->ref)(session); |
| |
| /* Parse and check optional cookie */ |
| if (session->peer_cookie_len > 0) { |
| if (memcmp(ptr, &session->peer_cookie[0], session->peer_cookie_len)) { |
| PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, |
| "%s: cookie mismatch (%u/%u). Discarding.\n", |
| tunnel->name, tunnel->tunnel_id, session->session_id); |
| u64_stats_update_begin(&sstats->syncp); |
| sstats->rx_cookie_discards++; |
| u64_stats_update_end(&sstats->syncp); |
| goto discard; |
| } |
| ptr += session->peer_cookie_len; |
| } |
| |
| /* Handle the optional sequence numbers. Sequence numbers are |
| * in different places for L2TPv2 and L2TPv3. |
| * |
| * 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. |
| */ |
| ns = nr = 0; |
| L2TP_SKB_CB(skb)->has_seq = 0; |
| if (tunnel->version == L2TP_HDR_VER_2) { |
| if (hdrflags & L2TP_HDRFLAG_S) { |
| ns = ntohs(*(__be16 *) ptr); |
| ptr += 2; |
| nr = ntohs(*(__be16 *) ptr); |
| ptr += 2; |
| |
| /* Store L2TP info in the skb */ |
| L2TP_SKB_CB(skb)->ns = ns; |
| L2TP_SKB_CB(skb)->has_seq = 1; |
| |
| PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| "%s: recv data ns=%u, nr=%u, session nr=%u\n", |
| session->name, ns, nr, session->nr); |
| } |
| } else if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { |
| u32 l2h = ntohl(*(__be32 *) ptr); |
| |
| if (l2h & 0x40000000) { |
| ns = l2h & 0x00ffffff; |
| |
| /* Store L2TP info in the skb */ |
| L2TP_SKB_CB(skb)->ns = ns; |
| L2TP_SKB_CB(skb)->has_seq = 1; |
| |
| PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| "%s: recv data ns=%u, session nr=%u\n", |
| session->name, ns, session->nr); |
| } |
| } |
| |
| /* Advance past L2-specific header, if present */ |
| ptr += session->l2specific_len; |
| |
| if (L2TP_SKB_CB(skb)->has_seq) { |
| /* 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, L2TP_MSG_SEQ, KERN_INFO, |
| "%s: requested to enable seq numbers by LNS\n", |
| session->name); |
| session->send_seq = -1; |
| l2tp_session_set_header_len(session, tunnel->version); |
| } |
| } else { |
| /* No sequence numbers. |
| * If user has configured mandatory sequence numbers, discard. |
| */ |
| if (session->recv_seq) { |
| PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING, |
| "%s: recv data has no seq numbers when required. " |
| "Discarding\n", session->name); |
| u64_stats_update_begin(&sstats->syncp); |
| sstats->rx_seq_discards++; |
| u64_stats_update_end(&sstats->syncp); |
| 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, L2TP_MSG_SEQ, KERN_INFO, |
| "%s: requested to disable seq numbers by LNS\n", |
| session->name); |
| session->send_seq = 0; |
| l2tp_session_set_header_len(session, tunnel->version); |
| } else if (session->send_seq) { |
| PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING, |
| "%s: recv data has no seq numbers when required. " |
| "Discarding\n", session->name); |
| u64_stats_update_begin(&sstats->syncp); |
| sstats->rx_seq_discards++; |
| u64_stats_update_end(&sstats->syncp); |
| goto discard; |
| } |
| } |
| |
| /* Session data offset is handled differently for L2TPv2 and |
| * L2TPv3. For L2TPv2, there is an optional 16-bit value in |
| * the header. For L2TPv3, the offset is negotiated using AVPs |
| * in the session setup control protocol. |
| */ |
| if (tunnel->version == L2TP_HDR_VER_2) { |
| /* If offset bit set, skip it. */ |
| if (hdrflags & L2TP_HDRFLAG_O) { |
| offset = ntohs(*(__be16 *)ptr); |
| ptr += 2 + offset; |
| } |
| } else |
| ptr += session->offset; |
| |
| offset = ptr - optr; |
| if (!pskb_may_pull(skb, offset)) |
| goto discard; |
| |
| __skb_pull(skb, offset); |
| |
| /* If caller wants to process the payload before we queue the |
| * packet, do so now. |
| */ |
| if (payload_hook) |
| if ((*payload_hook)(skb)) |
| goto discard; |
| |
| /* Prepare skb for adding to the session's reorder_q. Hold |
| * packets for max reorder_timeout or 1 second if not |
| * reordering. |
| */ |
| L2TP_SKB_CB(skb)->length = length; |
| L2TP_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 (L2TP_SKB_CB(skb)->has_seq) { |
| if (session->reorder_timeout != 0) { |
| /* Packet reordering enabled. Add skb to session's |
| * reorder queue, in order of ns. |
| */ |
| l2tp_recv_queue_skb(session, skb); |
| } else { |
| /* Packet reordering disabled. Discard out-of-sequence |
| * packets |
| */ |
| if (L2TP_SKB_CB(skb)->ns != session->nr) { |
| u64_stats_update_begin(&sstats->syncp); |
| sstats->rx_seq_discards++; |
| u64_stats_update_end(&sstats->syncp); |
| PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| "%s: oos pkt %u len %d discarded, " |
| "waiting for %u, reorder_q_len=%d\n", |
| session->name, L2TP_SKB_CB(skb)->ns, |
| L2TP_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. */ |
| l2tp_recv_dequeue(session); |
| |
| l2tp_session_dec_refcount(session); |
| |
| return; |
| |
| discard: |
| u64_stats_update_begin(&sstats->syncp); |
| sstats->rx_errors++; |
| u64_stats_update_end(&sstats->syncp); |
| kfree_skb(skb); |
| |
| if (session->deref) |
| (*session->deref)(session); |
| |
| l2tp_session_dec_refcount(session); |
| } |
| EXPORT_SYMBOL(l2tp_recv_common); |
| |
| /* Internal UDP 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 l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, |
| int (*payload_hook)(struct sk_buff *skb)) |
| { |
| struct l2tp_session *session = NULL; |
| unsigned char *ptr, *optr; |
| u16 hdrflags; |
| u32 tunnel_id, session_id; |
| int offset; |
| u16 version; |
| int length; |
| struct l2tp_stats *tstats; |
| |
| if (tunnel->sock && l2tp_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, L2TP_HDR_SIZE_SEQ)) { |
| PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, |
| "%s: recv short packet (len=%d)\n", tunnel->name, skb->len); |
| goto error; |
| } |
| |
| /* Trace packet contents, if enabled */ |
| if (tunnel->debug & L2TP_MSG_DATA) { |
| length = min(32u, skb->len); |
| if (!pskb_may_pull(skb, length)) |
| goto error; |
| |
| printk(KERN_DEBUG "%s: recv: ", tunnel->name); |
| |
| offset = 0; |
| do { |
| printk(" %02X", skb->data[offset]); |
| } while (++offset < length); |
| |
| printk("\n"); |
| } |
| |
| /* Point to L2TP header */ |
| optr = ptr = skb->data; |
| |
| /* Get L2TP header flags */ |
| hdrflags = ntohs(*(__be16 *) ptr); |
| |
| /* Check protocol version */ |
| version = hdrflags & L2TP_HDR_VER_MASK; |
| if (version != tunnel->version) { |
| PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, |
| "%s: recv protocol version mismatch: got %d expected %d\n", |
| tunnel->name, version, tunnel->version); |
| goto error; |
| } |
| |
| /* 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, L2TP_MSG_DATA, KERN_DEBUG, |
| "%s: recv control packet, len=%d\n", tunnel->name, length); |
| goto error; |
| } |
| |
| /* Skip flags */ |
| ptr += 2; |
| |
| if (tunnel->version == L2TP_HDR_VER_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; |
| } else { |
| ptr += 2; /* skip reserved bits */ |
| tunnel_id = tunnel->tunnel_id; |
| session_id = ntohl(*(__be32 *) ptr); |
| ptr += 4; |
| } |
| |
| /* Find the session context */ |
| session = l2tp_session_find(tunnel->l2tp_net, tunnel, session_id); |
| if (!session || !session->recv_skb) { |
| /* Not found? Pass to userspace to deal with */ |
| PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO, |
| "%s: no session found (%u/%u). Passing up.\n", |
| tunnel->name, tunnel_id, session_id); |
| goto error; |
| } |
| |
| l2tp_recv_common(session, skb, ptr, optr, hdrflags, length, payload_hook); |
| |
| return 0; |
| |
| discard_bad_csum: |
| LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name); |
| UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0); |
| tstats = &tunnel->stats; |
| u64_stats_update_begin(&tstats->syncp); |
| tstats->rx_errors++; |
| u64_stats_update_end(&tstats->syncp); |
| kfree_skb(skb); |
| |
| return 0; |
| |
| error: |
| /* Put UDP header back */ |
| __skb_push(skb, sizeof(struct udphdr)); |
| |
| 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. |
| */ |
| int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb) |
| { |
| struct l2tp_tunnel *tunnel; |
| |
| tunnel = l2tp_sock_to_tunnel(sk); |
| if (tunnel == NULL) |
| goto pass_up; |
| |
| PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_DEBUG, |
| "%s: received %d bytes\n", tunnel->name, skb->len); |
| |
| if (l2tp_udp_recv_core(tunnel, skb, tunnel->recv_payload_hook)) |
| goto pass_up_put; |
| |
| sock_put(sk); |
| return 0; |
| |
| pass_up_put: |
| sock_put(sk); |
| pass_up: |
| return 1; |
| } |
| EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv); |
| |
| /************************************************************************ |
| * Transmit handling |
| ***********************************************************************/ |
| |
| /* Build an L2TP header for the session into the buffer provided. |
| */ |
| static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf) |
| { |
| struct l2tp_tunnel *tunnel = session->tunnel; |
| __be16 *bufp = buf; |
| __be16 *optr = buf; |
| u16 flags = L2TP_HDR_VER_2; |
| u32 tunnel_id = tunnel->peer_tunnel_id; |
| u32 session_id = session->peer_session_id; |
| |
| if (session->send_seq) |
| flags |= L2TP_HDRFLAG_S; |
| |
| /* Setup L2TP header. */ |
| *bufp++ = htons(flags); |
| *bufp++ = htons(tunnel_id); |
| *bufp++ = htons(session_id); |
| if (session->send_seq) { |
| *bufp++ = htons(session->ns); |
| *bufp++ = 0; |
| session->ns++; |
| session->ns &= 0xffff; |
| PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| "%s: updated ns to %u\n", session->name, session->ns); |
| } |
| |
| return bufp - optr; |
| } |
| |
| static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf) |
| { |
| struct l2tp_tunnel *tunnel = session->tunnel; |
| char *bufp = buf; |
| char *optr = bufp; |
| |
| /* Setup L2TP header. The header differs slightly for UDP and |
| * IP encapsulations. For UDP, there is 4 bytes of flags. |
| */ |
| if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { |
| u16 flags = L2TP_HDR_VER_3; |
| *((__be16 *) bufp) = htons(flags); |
| bufp += 2; |
| *((__be16 *) bufp) = 0; |
| bufp += 2; |
| } |
| |
| *((__be32 *) bufp) = htonl(session->peer_session_id); |
| bufp += 4; |
| if (session->cookie_len) { |
| memcpy(bufp, &session->cookie[0], session->cookie_len); |
| bufp += session->cookie_len; |
| } |
| if (session->l2specific_len) { |
| if (session->l2specific_type == L2TP_L2SPECTYPE_DEFAULT) { |
| u32 l2h = 0; |
| if (session->send_seq) { |
| l2h = 0x40000000 | session->ns; |
| session->ns++; |
| session->ns &= 0xffffff; |
| PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG, |
| "%s: updated ns to %u\n", session->name, session->ns); |
| } |
| |
| *((__be32 *) bufp) = htonl(l2h); |
| } |
| bufp += session->l2specific_len; |
| } |
| if (session->offset) |
| bufp += session->offset; |
| |
| return bufp - optr; |
| } |
| |
| static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, |
| struct flowi *fl, size_t data_len) |
| { |
| struct l2tp_tunnel *tunnel = session->tunnel; |
| unsigned int len = skb->len; |
| int error; |
| struct l2tp_stats *tstats, *sstats; |
| |
| /* Debug */ |
| if (session->send_seq) |
| PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG, |
| "%s: send %Zd bytes, ns=%u\n", session->name, |
| data_len, session->ns - 1); |
| else |
| PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG, |
| "%s: send %Zd bytes\n", session->name, data_len); |
| |
| if (session->debug & L2TP_MSG_DATA) { |
| int i; |
| int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; |
| unsigned char *datap = skb->data + uhlen; |
| |
| printk(KERN_DEBUG "%s: xmit:", session->name); |
| for (i = 0; i < (len - uhlen); i++) { |
| printk(" %02X", *datap++); |
| if (i == 31) { |
| printk(" ..."); |
| break; |
| } |
| } |
| printk("\n"); |
| } |
| |
| /* Queue the packet to IP for output */ |
| skb->local_df = 1; |
| #if IS_ENABLED(CONFIG_IPV6) |
| if (skb->sk->sk_family == PF_INET6) |
| error = inet6_csk_xmit(skb, NULL); |
| else |
| #endif |
| error = ip_queue_xmit(skb, fl); |
| |
| /* Update stats */ |
| tstats = &tunnel->stats; |
| u64_stats_update_begin(&tstats->syncp); |
| sstats = &session->stats; |
| u64_stats_update_begin(&sstats->syncp); |
| if (error >= 0) { |
| tstats->tx_packets++; |
| tstats->tx_bytes += len; |
| sstats->tx_packets++; |
| sstats->tx_bytes += len; |
| } else { |
| tstats->tx_errors++; |
| sstats->tx_errors++; |
| } |
| u64_stats_update_end(&tstats->syncp); |
| u64_stats_update_end(&sstats->syncp); |
| |
| return 0; |
| } |
| |
| /* Automatically called when the skb is freed. |
| */ |
| static void l2tp_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 l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk) |
| { |
| sock_hold(sk); |
| skb->sk = sk; |
| skb->destructor = l2tp_sock_wfree; |
| } |
| |
| #if IS_ENABLED(CONFIG_IPV6) |
| static void l2tp_xmit_ipv6_csum(struct sock *sk, struct sk_buff *skb, |
| int udp_len) |
| { |
| struct ipv6_pinfo *np = inet6_sk(sk); |
| struct udphdr *uh = udp_hdr(skb); |
| |
| if (!skb_dst(skb) || !skb_dst(skb)->dev || |
| !(skb_dst(skb)->dev->features & NETIF_F_IPV6_CSUM)) { |
| __wsum csum = skb_checksum(skb, 0, udp_len, 0); |
| skb->ip_summed = CHECKSUM_UNNECESSARY; |
| uh->check = csum_ipv6_magic(&np->saddr, &np->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_ipv6_magic(&np->saddr, &np->daddr, |
| udp_len, IPPROTO_UDP, 0); |
| } |
| } |
| #endif |
| |
| /* If caller requires the skb to have a ppp header, the header must be |
| * inserted in the skb data before calling this function. |
| */ |
| int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len) |
| { |
| int data_len = skb->len; |
| struct l2tp_tunnel *tunnel = session->tunnel; |
| struct sock *sk = tunnel->sock; |
| struct flowi *fl; |
| struct udphdr *uh; |
| struct inet_sock *inet; |
| __wsum csum; |
| int old_headroom; |
| int new_headroom; |
| int headroom; |
| int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0; |
| int udp_len; |
| |
| /* Check that there's enough headroom in the skb to insert IP, |
| * UDP and L2TP headers. If not enough, expand it to |
| * make room. Adjust truesize. |
| */ |
| headroom = NET_SKB_PAD + sizeof(struct iphdr) + |
| uhlen + hdr_len; |
| old_headroom = skb_headroom(skb); |
| if (skb_cow_head(skb, headroom)) { |
| dev_kfree_skb(skb); |
| goto abort; |
| } |
| |
| new_headroom = skb_headroom(skb); |
| skb_orphan(skb); |
| skb->truesize += new_headroom - old_headroom; |
| |
| /* Setup L2TP header */ |
| session->build_header(session, __skb_push(skb, hdr_len)); |
| |
| /* Reset skb netfilter state */ |
| memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); |
| IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | |
| IPSKB_REROUTED); |
| nf_reset(skb); |
| |
| bh_lock_sock(sk); |
| if (sock_owned_by_user(sk)) { |
| dev_kfree_skb(skb); |
| goto out_unlock; |
| } |
| |
| /* Get routing info from the tunnel socket */ |
| skb_dst_drop(skb); |
| skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0))); |
| |
| inet = inet_sk(sk); |
| fl = &inet->cork.fl; |
| switch (tunnel->encap) { |
| case L2TP_ENCAPTYPE_UDP: |
| /* Setup UDP header */ |
| __skb_push(skb, sizeof(*uh)); |
| skb_reset_transport_header(skb); |
| uh = udp_hdr(skb); |
| uh->source = inet->inet_sport; |
| uh->dest = inet->inet_dport; |
| udp_len = uhlen + hdr_len + data_len; |
| uh->len = htons(udp_len); |
| uh->check = 0; |
| |
| /* Calculate UDP checksum if configured to do so */ |
| #if IS_ENABLED(CONFIG_IPV6) |
| if (sk->sk_family == PF_INET6) |
| l2tp_xmit_ipv6_csum(sk, skb, udp_len); |
| else |
| #endif |
| if (sk->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); |
| } |
| break; |
| |
| case L2TP_ENCAPTYPE_IP: |
| break; |
| } |
| |
| l2tp_skb_set_owner_w(skb, sk); |
| |
| l2tp_xmit_core(session, skb, fl, data_len); |
| out_unlock: |
| bh_unlock_sock(sk); |
| |
| abort: |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(l2tp_xmit_skb); |
| |
| /***************************************************************************** |
| * Tinnel and session create/destroy. |
| *****************************************************************************/ |
| |
| /* Tunnel socket destruct hook. |
| * The tunnel context is deleted only when all session sockets have been |
| * closed. |
| */ |
| static void l2tp_tunnel_destruct(struct sock *sk) |
| { |
| struct l2tp_tunnel *tunnel; |
| |
| tunnel = sk->sk_user_data; |
| if (tunnel == NULL) |
| goto end; |
| |
| PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, |
| "%s: closing...\n", tunnel->name); |
| |
| /* Close all sessions */ |
| l2tp_tunnel_closeall(tunnel); |
| |
| switch (tunnel->encap) { |
| case L2TP_ENCAPTYPE_UDP: |
| /* No longer an encapsulation socket. See net/ipv4/udp.c */ |
| (udp_sk(sk))->encap_type = 0; |
| (udp_sk(sk))->encap_rcv = NULL; |
| break; |
| case L2TP_ENCAPTYPE_IP: |
| break; |
| } |
| |
| /* Remove hooks into tunnel socket */ |
| tunnel->sock = NULL; |
| sk->sk_destruct = tunnel->old_sk_destruct; |
| sk->sk_user_data = NULL; |
| |
| /* Call the original destructor */ |
| if (sk->sk_destruct) |
| (*sk->sk_destruct)(sk); |
| |
| /* We're finished with the socket */ |
| l2tp_tunnel_dec_refcount(tunnel); |
| |
| end: |
| return; |
| } |
| |
| /* When the tunnel is closed, all the attached sessions need to go too. |
| */ |
| static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel) |
| { |
| int hash; |
| struct hlist_node *walk; |
| struct hlist_node *tmp; |
| struct l2tp_session *session; |
| |
| BUG_ON(tunnel == NULL); |
| |
| PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, |
| "%s: closing all sessions...\n", tunnel->name); |
| |
| write_lock_bh(&tunnel->hlist_lock); |
| for (hash = 0; hash < L2TP_HASH_SIZE; hash++) { |
| again: |
| hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) { |
| session = hlist_entry(walk, struct l2tp_session, hlist); |
| |
| PRINTK(session->debug, L2TP_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. |
| */ |
| if (session->ref != NULL) |
| (*session->ref)(session); |
| |
| write_unlock_bh(&tunnel->hlist_lock); |
| |
| if (tunnel->version != L2TP_HDR_VER_2) { |
| struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); |
| |
| spin_lock_bh(&pn->l2tp_session_hlist_lock); |
| hlist_del_init_rcu(&session->global_hlist); |
| spin_unlock_bh(&pn->l2tp_session_hlist_lock); |
| synchronize_rcu(); |
| } |
| |
| if (session->session_close != NULL) |
| (*session->session_close)(session); |
| |
| if (session->deref != NULL) |
| (*session->deref)(session); |
| |
| write_lock_bh(&tunnel->hlist_lock); |
| |
| /* 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. |
| */ |
| 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 l2tp_tunnel_free(struct l2tp_tunnel *tunnel) |
| { |
| struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); |
| |
| BUG_ON(atomic_read(&tunnel->ref_count) != 0); |
| BUG_ON(tunnel->sock != NULL); |
| |
| PRINTK(tunnel->debug, L2TP_MSG_CONTROL, KERN_INFO, |
| "%s: free...\n", tunnel->name); |
| |
| /* Remove from tunnel list */ |
| spin_lock_bh(&pn->l2tp_tunnel_list_lock); |
| list_del_rcu(&tunnel->list); |
| spin_unlock_bh(&pn->l2tp_tunnel_list_lock); |
| synchronize_rcu(); |
| |
| atomic_dec(&l2tp_tunnel_count); |
| kfree(tunnel); |
| } |
| |
| /* Create a socket for the tunnel, if one isn't set up by |
| * userspace. This is used for static tunnels where there is no |
| * managing L2TP daemon. |
| */ |
| static int l2tp_tunnel_sock_create(u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct socket **sockp) |
| { |
| int err = -EINVAL; |
| struct sockaddr_in udp_addr; |
| #if IS_ENABLED(CONFIG_IPV6) |
| struct sockaddr_in6 udp6_addr; |
| struct sockaddr_l2tpip6 ip6_addr; |
| #endif |
| struct sockaddr_l2tpip ip_addr; |
| struct socket *sock = NULL; |
| |
| switch (cfg->encap) { |
| case L2TP_ENCAPTYPE_UDP: |
| #if IS_ENABLED(CONFIG_IPV6) |
| if (cfg->local_ip6 && cfg->peer_ip6) { |
| err = sock_create(AF_INET6, SOCK_DGRAM, 0, sockp); |
| if (err < 0) |
| goto out; |
| |
| sock = *sockp; |
| |
| memset(&udp6_addr, 0, sizeof(udp6_addr)); |
| udp6_addr.sin6_family = AF_INET6; |
| memcpy(&udp6_addr.sin6_addr, cfg->local_ip6, |
| sizeof(udp6_addr.sin6_addr)); |
| udp6_addr.sin6_port = htons(cfg->local_udp_port); |
| err = kernel_bind(sock, (struct sockaddr *) &udp6_addr, |
| sizeof(udp6_addr)); |
| if (err < 0) |
| goto out; |
| |
| udp6_addr.sin6_family = AF_INET6; |
| memcpy(&udp6_addr.sin6_addr, cfg->peer_ip6, |
| sizeof(udp6_addr.sin6_addr)); |
| udp6_addr.sin6_port = htons(cfg->peer_udp_port); |
| err = kernel_connect(sock, |
| (struct sockaddr *) &udp6_addr, |
| sizeof(udp6_addr), 0); |
| if (err < 0) |
| goto out; |
| } else |
| #endif |
| { |
| err = sock_create(AF_INET, SOCK_DGRAM, 0, sockp); |
| if (err < 0) |
| goto out; |
| |
| sock = *sockp; |
| |
| memset(&udp_addr, 0, sizeof(udp_addr)); |
| udp_addr.sin_family = AF_INET; |
| udp_addr.sin_addr = cfg->local_ip; |
| udp_addr.sin_port = htons(cfg->local_udp_port); |
| err = kernel_bind(sock, (struct sockaddr *) &udp_addr, |
| sizeof(udp_addr)); |
| if (err < 0) |
| goto out; |
| |
| udp_addr.sin_family = AF_INET; |
| udp_addr.sin_addr = cfg->peer_ip; |
| udp_addr.sin_port = htons(cfg->peer_udp_port); |
| err = kernel_connect(sock, |
| (struct sockaddr *) &udp_addr, |
| sizeof(udp_addr), 0); |
| if (err < 0) |
| goto out; |
| } |
| |
| if (!cfg->use_udp_checksums) |
| sock->sk->sk_no_check = UDP_CSUM_NOXMIT; |
| |
| break; |
| |
| case L2TP_ENCAPTYPE_IP: |
| #if IS_ENABLED(CONFIG_IPV6) |
| if (cfg->local_ip6 && cfg->peer_ip6) { |
| err = sock_create(AF_INET6, SOCK_DGRAM, IPPROTO_L2TP, |
| sockp); |
| if (err < 0) |
| goto out; |
| |
| sock = *sockp; |
| |
| memset(&ip6_addr, 0, sizeof(ip6_addr)); |
| ip6_addr.l2tp_family = AF_INET6; |
| memcpy(&ip6_addr.l2tp_addr, cfg->local_ip6, |
| sizeof(ip6_addr.l2tp_addr)); |
| ip6_addr.l2tp_conn_id = tunnel_id; |
| err = kernel_bind(sock, (struct sockaddr *) &ip6_addr, |
| sizeof(ip6_addr)); |
| if (err < 0) |
| goto out; |
| |
| ip6_addr.l2tp_family = AF_INET6; |
| memcpy(&ip6_addr.l2tp_addr, cfg->peer_ip6, |
| sizeof(ip6_addr.l2tp_addr)); |
| ip6_addr.l2tp_conn_id = peer_tunnel_id; |
| err = kernel_connect(sock, |
| (struct sockaddr *) &ip6_addr, |
| sizeof(ip6_addr), 0); |
| if (err < 0) |
| goto out; |
| } else |
| #endif |
| { |
| err = sock_create(AF_INET, SOCK_DGRAM, IPPROTO_L2TP, |
| sockp); |
| if (err < 0) |
| goto out; |
| |
| sock = *sockp; |
| |
| memset(&ip_addr, 0, sizeof(ip_addr)); |
| ip_addr.l2tp_family = AF_INET; |
| ip_addr.l2tp_addr = cfg->local_ip; |
| ip_addr.l2tp_conn_id = tunnel_id; |
| err = kernel_bind(sock, (struct sockaddr *) &ip_addr, |
| sizeof(ip_addr)); |
| if (err < 0) |
| goto out; |
| |
| ip_addr.l2tp_family = AF_INET; |
| ip_addr.l2tp_addr = cfg->peer_ip; |
| ip_addr.l2tp_conn_id = peer_tunnel_id; |
| err = kernel_connect(sock, (struct sockaddr *) &ip_addr, |
| sizeof(ip_addr), 0); |
| if (err < 0) |
| goto out; |
| } |
| break; |
| |
| default: |
| goto out; |
| } |
| |
| out: |
| if ((err < 0) && sock) { |
| sock_release(sock); |
| *sockp = NULL; |
| } |
| |
| return err; |
| } |
| |
| int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg, struct l2tp_tunnel **tunnelp) |
| { |
| struct l2tp_tunnel *tunnel = NULL; |
| int err; |
| struct socket *sock = NULL; |
| struct sock *sk = NULL; |
| struct l2tp_net *pn; |
| enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP; |
| |
| /* Get the tunnel socket from the fd, which was opened by |
| * the userspace L2TP daemon. If not specified, create a |
| * kernel socket. |
| */ |
| if (fd < 0) { |
| err = l2tp_tunnel_sock_create(tunnel_id, peer_tunnel_id, cfg, &sock); |
| if (err < 0) |
| goto err; |
| } else { |
| err = -EBADF; |
| sock = sockfd_lookup(fd, &err); |
| if (!sock) { |
| printk(KERN_ERR "tunl %hu: sockfd_lookup(fd=%d) returned %d\n", |
| tunnel_id, fd, err); |
| goto err; |
| } |
| } |
| |
| sk = sock->sk; |
| |
| if (cfg != NULL) |
| encap = cfg->encap; |
| |
| /* Quick sanity checks */ |
| switch (encap) { |
| case L2TP_ENCAPTYPE_UDP: |
| err = -EPROTONOSUPPORT; |
| if (sk->sk_protocol != IPPROTO_UDP) { |
| printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n", |
| tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP); |
| goto err; |
| } |
| break; |
| case L2TP_ENCAPTYPE_IP: |
| err = -EPROTONOSUPPORT; |
| if (sk->sk_protocol != IPPROTO_L2TP) { |
| printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n", |
| tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP); |
| goto err; |
| } |
| break; |
| } |
| |
| /* Check if this socket has already been prepped */ |
| tunnel = (struct l2tp_tunnel *)sk->sk_user_data; |
| if (tunnel != NULL) { |
| /* This socket has already been prepped */ |
| err = -EBUSY; |
| goto err; |
| } |
| |
| tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL); |
| if (tunnel == NULL) { |
| err = -ENOMEM; |
| goto err; |
| } |
| |
| tunnel->version = version; |
| tunnel->tunnel_id = tunnel_id; |
| tunnel->peer_tunnel_id = peer_tunnel_id; |
| tunnel->debug = L2TP_DEFAULT_DEBUG_FLAGS; |
| |
| tunnel->magic = L2TP_TUNNEL_MAGIC; |
| sprintf(&tunnel->name[0], "tunl %u", tunnel_id); |
| rwlock_init(&tunnel->hlist_lock); |
| |
| /* The net we belong to */ |
| tunnel->l2tp_net = net; |
| pn = l2tp_pernet(net); |
| |
| if (cfg != NULL) |
| tunnel->debug = cfg->debug; |
| |
| /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ |
| tunnel->encap = encap; |
| if (encap == L2TP_ENCAPTYPE_UDP) { |
| /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ |
| udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP; |
| udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv; |
| #if IS_ENABLED(CONFIG_IPV6) |
| if (sk->sk_family == PF_INET6) |
| udpv6_encap_enable(); |
| else |
| #endif |
| udp_encap_enable(); |
| } |
| |
| sk->sk_user_data = tunnel; |
| |
| /* 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 = &l2tp_tunnel_destruct; |
| tunnel->sock = sk; |
| sk->sk_allocation = GFP_ATOMIC; |
| |
| /* Add tunnel to our list */ |
| INIT_LIST_HEAD(&tunnel->list); |
| atomic_inc(&l2tp_tunnel_count); |
| |
| /* Bump the reference count. The tunnel context is deleted |
| * only when this drops to zero. Must be done before list insertion |
| */ |
| l2tp_tunnel_inc_refcount(tunnel); |
| spin_lock_bh(&pn->l2tp_tunnel_list_lock); |
| list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list); |
| spin_unlock_bh(&pn->l2tp_tunnel_list_lock); |
| |
| err = 0; |
| err: |
| if (tunnelp) |
| *tunnelp = tunnel; |
| |
| /* If tunnel's socket was created by the kernel, it doesn't |
| * have a file. |
| */ |
| if (sock && sock->file) |
| sockfd_put(sock); |
| |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(l2tp_tunnel_create); |
| |
| /* This function is used by the netlink TUNNEL_DELETE command. |
| */ |
| int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel) |
| { |
| int err = 0; |
| struct socket *sock = tunnel->sock ? tunnel->sock->sk_socket : NULL; |
| |
| /* Force the tunnel socket to close. This will eventually |
| * cause the tunnel to be deleted via the normal socket close |
| * mechanisms when userspace closes the tunnel socket. |
| */ |
| if (sock != NULL) { |
| err = inet_shutdown(sock, 2); |
| |
| /* If the tunnel's socket was created by the kernel, |
| * close the socket here since the socket was not |
| * created by userspace. |
| */ |
| if (sock->file == NULL) |
| err = inet_release(sock); |
| } |
| |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(l2tp_tunnel_delete); |
| |
| /* Really kill the session. |
| */ |
| void l2tp_session_free(struct l2tp_session *session) |
| { |
| struct l2tp_tunnel *tunnel; |
| |
| BUG_ON(atomic_read(&session->ref_count) != 0); |
| |
| tunnel = session->tunnel; |
| if (tunnel != NULL) { |
| BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC); |
| |
| /* Delete the session from the hash */ |
| write_lock_bh(&tunnel->hlist_lock); |
| hlist_del_init(&session->hlist); |
| write_unlock_bh(&tunnel->hlist_lock); |
| |
| /* Unlink from the global hash if not L2TPv2 */ |
| if (tunnel->version != L2TP_HDR_VER_2) { |
| struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); |
| |
| spin_lock_bh(&pn->l2tp_session_hlist_lock); |
| hlist_del_init_rcu(&session->global_hlist); |
| spin_unlock_bh(&pn->l2tp_session_hlist_lock); |
| synchronize_rcu(); |
| } |
| |
| if (session->session_id != 0) |
| atomic_dec(&l2tp_session_count); |
| |
| sock_put(tunnel->sock); |
| |
| /* This will delete the tunnel context if this |
| * is the last session on the tunnel. |
| */ |
| session->tunnel = NULL; |
| l2tp_tunnel_dec_refcount(tunnel); |
| } |
| |
| kfree(session); |
| |
| return; |
| } |
| EXPORT_SYMBOL_GPL(l2tp_session_free); |
| |
| /* This function is used by the netlink SESSION_DELETE command and by |
| pseudowire modules. |
| */ |
| int l2tp_session_delete(struct l2tp_session *session) |
| { |
| if (session->session_close != NULL) |
| (*session->session_close)(session); |
| |
| l2tp_session_dec_refcount(session); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(l2tp_session_delete); |
| |
| |
| /* We come here whenever a session's send_seq, cookie_len or |
| * l2specific_len parameters are set. |
| */ |
| static void l2tp_session_set_header_len(struct l2tp_session *session, int version) |
| { |
| if (version == L2TP_HDR_VER_2) { |
| session->hdr_len = 6; |
| if (session->send_seq) |
| session->hdr_len += 4; |
| } else { |
| session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset; |
| if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP) |
| session->hdr_len += 4; |
| } |
| |
| } |
| |
| struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunnel, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg) |
| { |
| struct l2tp_session *session; |
| |
| session = kzalloc(sizeof(struct l2tp_session) + priv_size, GFP_KERNEL); |
| if (session != NULL) { |
| session->magic = L2TP_SESSION_MAGIC; |
| session->tunnel = tunnel; |
| |
| session->session_id = session_id; |
| session->peer_session_id = peer_session_id; |
| session->nr = 0; |
| |
| sprintf(&session->name[0], "sess %u/%u", |
| tunnel->tunnel_id, session->session_id); |
| |
| skb_queue_head_init(&session->reorder_q); |
| |
| INIT_HLIST_NODE(&session->hlist); |
| INIT_HLIST_NODE(&session->global_hlist); |
| |
| /* Inherit debug options from tunnel */ |
| session->debug = tunnel->debug; |
| |
| if (cfg) { |
| session->pwtype = cfg->pw_type; |
| session->debug = cfg->debug; |
| session->mtu = cfg->mtu; |
| session->mru = cfg->mru; |
| session->send_seq = cfg->send_seq; |
| session->recv_seq = cfg->recv_seq; |
| session->lns_mode = cfg->lns_mode; |
| session->reorder_timeout = cfg->reorder_timeout; |
| session->offset = cfg->offset; |
| session->l2specific_type = cfg->l2specific_type; |
| session->l2specific_len = cfg->l2specific_len; |
| session->cookie_len = cfg->cookie_len; |
| memcpy(&session->cookie[0], &cfg->cookie[0], cfg->cookie_len); |
| session->peer_cookie_len = cfg->peer_cookie_len; |
| memcpy(&session->peer_cookie[0], &cfg->peer_cookie[0], cfg->peer_cookie_len); |
| } |
| |
| if (tunnel->version == L2TP_HDR_VER_2) |
| session->build_header = l2tp_build_l2tpv2_header; |
| else |
| session->build_header = l2tp_build_l2tpv3_header; |
| |
| l2tp_session_set_header_len(session, tunnel->version); |
| |
| /* Bump the reference count. The session context is deleted |
| * only when this drops to zero. |
| */ |
| l2tp_session_inc_refcount(session); |
| l2tp_tunnel_inc_refcount(tunnel); |
| |
| /* Ensure tunnel socket isn't deleted */ |
| sock_hold(tunnel->sock); |
| |
| /* Add session to the tunnel's hash list */ |
| write_lock_bh(&tunnel->hlist_lock); |
| hlist_add_head(&session->hlist, |
| l2tp_session_id_hash(tunnel, session_id)); |
| write_unlock_bh(&tunnel->hlist_lock); |
| |
| /* And to the global session list if L2TPv3 */ |
| if (tunnel->version != L2TP_HDR_VER_2) { |
| struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net); |
| |
| spin_lock_bh(&pn->l2tp_session_hlist_lock); |
| hlist_add_head_rcu(&session->global_hlist, |
| l2tp_session_id_hash_2(pn, session_id)); |
| spin_unlock_bh(&pn->l2tp_session_hlist_lock); |
| } |
| |
| /* Ignore management session in session count value */ |
| if (session->session_id != 0) |
| atomic_inc(&l2tp_session_count); |
| } |
| |
| return session; |
| } |
| EXPORT_SYMBOL_GPL(l2tp_session_create); |
| |
| /***************************************************************************** |
| * Init and cleanup |
| *****************************************************************************/ |
| |
| static __net_init int l2tp_init_net(struct net *net) |
| { |
| struct l2tp_net *pn = net_generic(net, l2tp_net_id); |
| int hash; |
| |
| INIT_LIST_HEAD(&pn->l2tp_tunnel_list); |
| spin_lock_init(&pn->l2tp_tunnel_list_lock); |
| |
| for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++) |
| INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]); |
| |
| spin_lock_init(&pn->l2tp_session_hlist_lock); |
| |
| return 0; |
| } |
| |
| static struct pernet_operations l2tp_net_ops = { |
| .init = l2tp_init_net, |
| .id = &l2tp_net_id, |
| .size = sizeof(struct l2tp_net), |
| }; |
| |
| static int __init l2tp_init(void) |
| { |
| int rc = 0; |
| |
| rc = register_pernet_device(&l2tp_net_ops); |
| if (rc) |
| goto out; |
| |
| printk(KERN_INFO "L2TP core driver, %s\n", L2TP_DRV_VERSION); |
| |
| out: |
| return rc; |
| } |
| |
| static void __exit l2tp_exit(void) |
| { |
| unregister_pernet_device(&l2tp_net_ops); |
| } |
| |
| module_init(l2tp_init); |
| module_exit(l2tp_exit); |
| |
| MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); |
| MODULE_DESCRIPTION("L2TP core"); |
| MODULE_LICENSE("GPL"); |
| MODULE_VERSION(L2TP_DRV_VERSION); |
| |