@@ -19,6 +19,10 @@ menuconfig L2TP
connections. L2TP is also used as a VPN protocol, popular
with home workers to connect to their offices.
+ L2TPv3 allows other protocols as well as PPP to be carried
+ over L2TP tunnels. L2TPv3 is defined in RFC 3931
+ <http://www.ietf.org/rfc/rfc3931.txt>.
+
The kernel component handles only L2TP data packets: a
userland daemon handles L2TP the control protocol (tunnel
and session setup). One such daemon is OpenL2TP
@@ -26,3 +30,24 @@ menuconfig L2TP
If you don't need L2TP, say N. To compile all L2TP code as
modules, choose M here.
+
+config L2TP_V3
+ bool "L2TPv3 support (EXPERIMENTAL)"
+ depends on EXPERIMENTAL && L2TP
+ help
+ Layer Two Tunneling Protocol Version 3
+
+ From RFC 3931 <http://www.ietf.org/rfc/rfc3931.txt>.
+
+ The Layer Two Tunneling Protocol (L2TP) provides a dynamic
+ mechanism for tunneling Layer 2 (L2) "circuits" across a
+ packet-oriented data network (e.g., over IP). L2TP, as
+ originally defined in RFC 2661, is a standard method for
+ tunneling Point-to-Point Protocol (PPP) [RFC1661] sessions.
+ L2TP has since been adopted for tunneling a number of other
+ L2 protocols, including ATM, Frame Relay, HDLC and even raw
+ ethernet frames.
+
+ If you are connecting to L2TPv3 equipment, or you want to
+ tunnel raw ethernet frames using L2TP, say Y here. If
+ unsure, say N.
@@ -66,6 +66,7 @@
#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
@@ -86,7 +87,7 @@
/* Private data stored for received packets in the skb.
*/
struct l2tp_skb_cb {
- u16 ns;
+ u32 ns;
u16 has_seq;
u16 length;
unsigned long expires;
@@ -102,6 +103,8 @@ static unsigned int l2tp_net_id;
struct l2tp_net {
struct list_head l2tp_tunnel_list;
rwlock_t l2tp_tunnel_list_lock;
+ struct hlist_head l2tp_session_hlist[L2TP_HASH_SIZE_2];
+ rwlock_t l2tp_session_hlist_lock;
};
static inline struct l2tp_net *l2tp_pernet(struct net *net)
@@ -111,6 +114,42 @@ static inline struct l2tp_net *l2tp_pernet(struct net *net)
return net_generic(net, l2tp_net_id);
}
+/* 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)
+{
+ unsigned long hash_val = (unsigned long) session_id;
+
+ return &pn->l2tp_session_hlist[hash_long(hash_val, 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;
+
+ read_lock_bh(&pn->l2tp_session_hlist_lock);
+ hlist_for_each_entry(session, walk, session_list, global_hlist) {
+ if (session->session_id == session_id) {
+ read_unlock_bh(&pn->l2tp_session_hlist_lock);
+ return session;
+ }
+ }
+ read_unlock_bh(&pn->l2tp_session_hlist_lock);
+
+ return NULL;
+}
+
/* Session hash list.
* The session_id SHOULD be random according to RFC2661, but several
* L2TP implementations (Cisco and Microsoft) use incrementing
@@ -126,13 +165,20 @@ l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
/* Lookup a session by id
*/
-struct l2tp_session *l2tp_session_find(struct l2tp_tunnel *tunnel, u32 session_id)
+struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id)
{
- struct hlist_head *session_list =
- l2tp_session_id_hash(tunnel, 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) {
@@ -223,7 +269,7 @@ static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *sk
{
struct sk_buff *skbp;
struct sk_buff *tmp;
- u16 ns = L2TP_SKB_CB(skb)->ns;
+ u32 ns = L2TP_SKB_CB(skb)->ns;
spin_lock_bh(&session->reorder_q.lock);
skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
@@ -264,6 +310,11 @@ static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *
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);
}
@@ -296,8 +347,8 @@ static void l2tp_recv_dequeue(struct l2tp_session *session)
session->stats.rx_seq_discards++;
session->stats.rx_errors++;
PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
- "%s: oos pkt %hu len %d discarded (too old), "
- "waiting for %hu, reorder_q_len=%d\n",
+ "%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));
@@ -311,8 +362,8 @@ static void l2tp_recv_dequeue(struct l2tp_session *session)
if (L2TP_SKB_CB(skb)->has_seq) {
if (L2TP_SKB_CB(skb)->ns != session->nr) {
PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
- "%s: holding oos pkt %hu len %d, "
- "waiting for %hu, reorder_q_len=%d\n",
+ "%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));
@@ -357,100 +408,73 @@ static inline int l2tp_verify_udp_checksum(struct sock *sk,
return __skb_checksum_complete(skb);
}
-/* 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.
+/* 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.
*/
-int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
- int (*payload_hook)(struct sk_buff *skb))
+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_session *session = NULL;
- unsigned char *ptr, *optr;
- u16 hdrflags;
- u32 tunnel_id, session_id;
- int length;
+ struct l2tp_tunnel *tunnel = session->tunnel;
int offset;
- u16 version;
- u16 ns, nr;
-
- 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;
- }
-
- /* Point to L2TP header */
- optr = ptr = skb->data;
-
- /* 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", ptr[offset]);
- } while (++offset < length);
-
- printk("\n");
- }
-
- /* 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 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 = l2tp_session_find(tunnel, session_id);
- if (!session) {
- /* Not found? Pass to userspace to deal with */
- PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
- "%s: no session found (%hu/%hu). Passing up.\n",
- tunnel->name, tunnel_id, session_id);
- goto error;
- }
+ u32 ns, nr;
/* The ref count is increased since we now hold a pointer to
* the session. Take care to decrement the refcnt when exiting
@@ -460,6 +484,18 @@ int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
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);
+ session->stats.rx_cookie_discards++;
+ goto discard;
+ }
+ ptr += session->peer_cookie_len;
+ }
+
/* Handle the optional sequence numbers. Sequence numbers are
* in different places for L2TPv2 and L2TPv3.
*
@@ -469,21 +505,40 @@ int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
*/
ns = nr = 0;
L2TP_SKB_CB(skb)->has_seq = 0;
- if (hdrflags & L2TP_HDRFLAG_S) {
- ns = (u16) ntohs(*(__be16 *) ptr);
- ptr += 2;
- nr = ntohs(*(__be16 *) ptr);
- ptr += 2;
+ 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;
+ /* 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=%hu, nr=%hu, session nr=%hu\n",
- session->name, ns, nr, session->nr);
+ 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,
@@ -494,6 +549,7 @@ int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
"%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.
@@ -517,6 +573,7 @@ int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
"%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. "
@@ -526,11 +583,19 @@ int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
}
}
- /* If offset bit set, skip it. */
- if (hdrflags & L2TP_HDRFLAG_O) {
- offset = ntohs(*(__be16 *)ptr);
- ptr += 2 + offset;
- }
+ /* 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))
@@ -569,8 +634,8 @@ int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
if (L2TP_SKB_CB(skb)->ns != session->nr) {
session->stats.rx_seq_discards++;
PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
- "%s: oos pkt %hu len %d discarded, "
- "waiting for %hu, reorder_q_len=%d\n",
+ "%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));
@@ -591,7 +656,7 @@ int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
l2tp_session_dec_refcount(session);
- return 0;
+ return;
discard:
session->stats.rx_errors++;
@@ -601,6 +666,111 @@ discard:
(*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.
+ */
+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;
+
+ 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;
+ }
+
+ /* Point to L2TP header */
+ optr = ptr = skb->data;
+
+ /* 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", ptr[offset]);
+ } while (++offset < length);
+
+ printk("\n");
+ }
+
+ /* 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) {
+ /* 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;
@@ -656,11 +826,11 @@ EXPORT_SYMBOL_GPL(l2tp_udp_encap_recv);
/* Build an L2TP header for the session into the buffer provided.
*/
-static void l2tp_build_l2tpv2_header(struct l2tp_tunnel *tunnel,
- struct l2tp_session *session,
- void *buf)
+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;
@@ -676,19 +846,51 @@ static void l2tp_build_l2tpv2_header(struct l2tp_tunnel *tunnel,
*bufp++ = htons(session->ns);
*bufp++ = 0;
session->ns++;
+ session->ns &= 0xffff;
PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
- "%s: updated ns to %hu\n", session->name, session->ns);
+ "%s: updated ns to %u\n", session->name, session->ns);
}
+
+ return bufp - optr;
}
-void l2tp_build_l2tp_header(struct l2tp_session *session, void *buf)
+static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
{
- struct l2tp_tunnel *tunnel = session->tunnel;
+ char *bufp = buf;
+ char *optr = bufp;
+ u16 flags = L2TP_HDR_VER_3;
- BUG_ON(tunnel->version != L2TP_HDR_VER_2);
- l2tp_build_l2tpv2_header(tunnel, session, buf);
+ /* Setup L2TP header. */
+ *((__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;
}
-EXPORT_SYMBOL_GPL(l2tp_build_l2tp_header);
int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, size_t data_len)
{
@@ -699,7 +901,7 @@ int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, size_t dat
/* Debug */
if (session->send_seq)
PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
- "%s: send %Zd bytes, ns=%hu\n", session->name,
+ "%s: send %Zd bytes, ns=%u\n", session->name,
data_len, session->ns - 1);
else
PRINTK(session->debug, L2TP_MSG_DATA, KERN_DEBUG,
@@ -785,7 +987,7 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
skb->truesize += new_headroom - old_headroom;
/* Setup L2TP header */
- l2tp_build_l2tp_header(session, __skb_push(skb, hdr_len));
+ session->build_header(session, __skb_push(skb, hdr_len));
udp_len = sizeof(struct udphdr) + hdr_len + data_len;
/* Setup UDP header */
@@ -796,7 +998,6 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
uh->source = inet->inet_sport;
uh->dest = inet->inet_dport;
uh->len = htons(udp_len);
-
uh->check = 0;
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
@@ -916,6 +1117,14 @@ again:
write_unlock_bh(&tunnel->hlist_lock);
+ if (tunnel->version != L2TP_HDR_VER_2) {
+ struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
+
+ write_lock_bh(&pn->l2tp_session_hlist_lock);
+ hlist_del_init(&session->global_hlist);
+ write_unlock_bh(&pn->l2tp_session_hlist_lock);
+ }
+
if (session->session_close != NULL)
(*session->session_close)(session);
@@ -1002,9 +1211,6 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
goto err;
}
- if (version != L2TP_HDR_VER_2)
- goto err;
-
tunnel = kzalloc(sizeof(struct l2tp_tunnel), GFP_KERNEL);
if (tunnel == NULL) {
err = -ENOMEM;
@@ -1082,6 +1288,15 @@ void l2tp_session_free(struct l2tp_session *session)
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);
+
+ write_lock_bh(&pn->l2tp_session_hlist_lock);
+ hlist_del_init(&session->global_hlist);
+ write_unlock_bh(&pn->l2tp_session_hlist_lock);
+ }
+
if (session->session_id != 0)
atomic_dec(&l2tp_session_count);
@@ -1100,6 +1315,22 @@ void l2tp_session_free(struct l2tp_session *session)
}
EXPORT_SYMBOL_GPL(l2tp_session_free);
+/* We come here whenever a session's send_seq, cookie_len or
+ * l2specific_len parameters are set.
+ */
+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 = 8 + session->cookie_len + session->l2specific_len + session->offset;
+ }
+
+}
+EXPORT_SYMBOL_GPL(l2tp_session_set_header_len);
+
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;
@@ -1111,6 +1342,7 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
session->session_id = session_id;
session->peer_session_id = peer_session_id;
+ session->nr = 1;
sprintf(&session->name[0], "sess %u/%u",
tunnel->tunnel_id, session->session_id);
@@ -1118,20 +1350,36 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
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->hdr_len = cfg->hdr_len;
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.
*/
@@ -1147,6 +1395,16 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
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);
+
+ write_lock_bh(&pn->l2tp_session_hlist_lock);
+ hlist_add_head(&session->global_hlist,
+ l2tp_session_id_hash_2(pn, session_id));
+ write_unlock_bh(&pn->l2tp_session_hlist_lock);
+ }
+
/* Ignore management session in session count value */
if (session->session_id != 0)
atomic_inc(&l2tp_session_count);
@@ -1290,6 +1548,7 @@ static void l2tp_seq_tunnel_show(struct seq_file *m, void *v)
seq_printf(m, " source port %hu, dest port %hu\n",
ntohs(inet->inet_sport), ntohs(inet->inet_dport));
}
+ seq_printf(m, " L2TPv%d\n", tunnel->version);
seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,
tunnel->sock ? atomic_read(&tunnel->sock->sk_refcnt) : 0,
atomic_read(&tunnel->ref_count));
@@ -1311,17 +1570,46 @@ static void l2tp_seq_session_show(struct seq_file *m, void *v)
{
struct l2tp_session *session = v;
- seq_printf(m, " SESSION %u, peer %u\n", session->session_id, session->peer_session_id);
+ seq_printf(m, " SESSION %u, peer %u, %s\n", session->session_id,
+ session->peer_session_id,
+ session->pwtype == L2TP_PWTYPE_ETH ? "ETH" :
+ session->pwtype == L2TP_PWTYPE_PPP ? "PPP" :
+ "");
if (session->send_seq || session->recv_seq)
seq_printf(m, " nr %hu, ns %hu\n", session->nr, session->ns);
seq_printf(m, " refcnt %d\n", atomic_read(&session->ref_count));
- seq_printf(m, " config %d/%d/%c/%c/%s %08x %u\n",
+ seq_printf(m, " config %d/%d/%c/%c/%s/%s %08x %u\n",
session->mtu, session->mru,
session->recv_seq ? 'R' : '-',
session->send_seq ? 'S' : '-',
+ session->data_seq == 1 ? "IPSEQ" :
+ session->data_seq == 2 ? "DATASEQ" : "-",
session->lns_mode ? "LNS" : "LAC",
session->debug,
jiffies_to_msecs(session->reorder_timeout));
+ seq_printf(m, " offset %hu l2specific %hu/%hu\n",
+ session->offset, session->l2specific_type, session->l2specific_len);
+ if (session->cookie_len) {
+ seq_printf(m, " cookie %02x%02x%02x%02x",
+ session->cookie[0], session->cookie[1],
+ session->cookie[2], session->cookie[3]);
+ if (session->cookie_len == 8)
+ seq_printf(m, "%02x%02x%02x%02x",
+ session->cookie[4], session->cookie[5],
+ session->cookie[6], session->cookie[7]);
+ seq_printf(m, "\n");
+ }
+ if (session->peer_cookie_len) {
+ seq_printf(m, " peer cookie %02x%02x%02x%02x",
+ session->peer_cookie[0], session->peer_cookie[1],
+ session->peer_cookie[2], session->peer_cookie[3]);
+ if (session->peer_cookie_len == 8)
+ seq_printf(m, "%02x%02x%02x%02x",
+ session->peer_cookie[4], session->peer_cookie[5],
+ session->peer_cookie[6], session->peer_cookie[7]);
+ seq_printf(m, "\n");
+ }
+
seq_printf(m, " %hu/%hu tx %llu/%llu/%llu rx %llu/%llu/%llu\n",
session->nr, session->ns,
(unsigned long long)session->stats.tx_packets,
@@ -1343,11 +1631,15 @@ static int l2tp_seq_show(struct seq_file *m, void *v)
if (v == SEQ_START_TOKEN) {
seq_puts(m, "L2TP driver info, " L2TP_DRV_VERSION "\n");
seq_puts(m, "TUNNEL ID, peer ID from IP to IP\n");
+ seq_puts(m, " L2TPv2/L2TPv3\n");
seq_puts(m, " sessions session-count, refcnt refcnt/sk->refcnt\n");
seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
- seq_puts(m, " SESSION ID, peer ID\n");
+ seq_puts(m, " SESSION ID, peer ID, PWTYPE\n");
seq_puts(m, " refcnt cnt\n");
- seq_puts(m, " mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
+ seq_puts(m, " offset OFFSET l2specific TYPE/LEN\n");
+ seq_puts(m, " [ cookie ]\n");
+ seq_puts(m, " [ peer cookie ]\n");
+ seq_puts(m, " config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n");
seq_puts(m, " nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
seq_printf(m, "tunnels %d sessions %d\n", atomic_read(&l2tp_tunnel_count), atomic_read(&l2tp_session_count));
@@ -1397,6 +1689,7 @@ static __net_init int l2tp_init_net(struct net *net)
struct l2tp_net *pn;
struct proc_dir_entry *pde;
int err;
+ int hash;
pn = kzalloc(sizeof(*pn), GFP_KERNEL);
if (!pn)
@@ -1405,6 +1698,11 @@ static __net_init int l2tp_init_net(struct net *net)
INIT_LIST_HEAD(&pn->l2tp_tunnel_list);
rwlock_init(&pn->l2tp_tunnel_list_lock);
+ for (hash = 0; hash < L2TP_HASH_SIZE_2; hash++)
+ INIT_HLIST_HEAD(&pn->l2tp_session_hlist[hash]);
+
+ rwlock_init(&pn->l2tp_session_hlist_lock);
+
err = net_assign_generic(net, l2tp_net_id, pn);
if (err)
goto out;
@@ -15,9 +15,14 @@
#define L2TP_TUNNEL_MAGIC 0x42114DDA
#define L2TP_SESSION_MAGIC 0x0C04EB7D
+/* Per tunnel, session hash table size */
#define L2TP_HASH_BITS 4
#define L2TP_HASH_SIZE (1 << L2TP_HASH_BITS)
+/* System-wide, session hash table size */
+#define L2TP_HASH_BITS_2 8
+#define L2TP_HASH_SIZE_2 (1 << L2TP_HASH_BITS_2)
+
/* Debug message categories for the DEBUG socket option */
enum {
L2TP_MSG_DEBUG = (1 << 0), /* verbose debug (if
@@ -28,6 +33,21 @@ enum {
L2TP_MSG_DATA = (1 << 3), /* data packets */
};
+enum l2tp_pwtype {
+ L2TP_PWTYPE_NONE = 0x0000,
+ L2TP_PWTYPE_ETH_VLAN = 0x0004,
+ L2TP_PWTYPE_ETH = 0x0005,
+ L2TP_PWTYPE_PPP = 0x0007,
+ L2TP_PWTYPE_PPP_AC = 0x0008,
+ L2TP_PWTYPE_IP = 0x000b,
+ __L2TP_PWTYPE_MAX
+};
+
+enum l2tp_l2spec_type {
+ L2TP_L2SPECTYPE_NONE,
+ L2TP_L2SPECTYPE_DEFAULT,
+};
+
struct sk_buff;
struct l2tp_stats {
@@ -39,6 +59,7 @@ struct l2tp_stats {
u64 rx_seq_discards;
u64 rx_oos_packets;
u64 rx_errors;
+ u64 rx_cookie_discards;
};
struct l2tp_tunnel;
@@ -47,6 +68,7 @@ struct l2tp_tunnel;
* packets and transmit outgoing ones.
*/
struct l2tp_session_cfg {
+ enum l2tp_pwtype pw_type;
unsigned data_seq:2; /* data sequencing level
* 0 => none, 1 => IP only,
* 2 => all
@@ -60,12 +82,17 @@ struct l2tp_session_cfg {
* control of LNS. */
int debug; /* bitmask of debug message
* categories */
- int offset; /* offset to payload */
+ u16 offset; /* offset to payload */
+ u16 l2specific_len; /* Layer 2 specific length */
+ u16 l2specific_type; /* Layer 2 specific type */
+ u8 cookie[8]; /* optional cookie */
+ int cookie_len; /* 0, 4 or 8 bytes */
+ u8 peer_cookie[8]; /* peer's cookie */
+ int peer_cookie_len; /* 0, 4 or 8 bytes */
int reorder_timeout; /* configured reorder timeout
* (in jiffies) */
int mtu;
int mru;
- int hdr_len;
};
struct l2tp_session {
@@ -76,8 +103,17 @@ struct l2tp_session {
* context */
u32 session_id;
u32 peer_session_id;
- u16 nr; /* session NR state (receive) */
- u16 ns; /* session NR state (send) */
+ u8 cookie[8];
+ int cookie_len;
+ u8 peer_cookie[8];
+ int peer_cookie_len;
+ u16 offset; /* offset from end of L2TP header
+ to beginning of data */
+ u16 l2specific_len;
+ u16 l2specific_type;
+ u16 hdr_len;
+ u32 nr; /* session NR state (receive) */
+ u32 ns; /* session NR state (send) */
struct sk_buff_head reorder_q; /* receive reorder queue */
struct hlist_node hlist; /* Hash list node */
atomic_t ref_count;
@@ -100,9 +136,11 @@ struct l2tp_session {
* (in jiffies) */
int mtu;
int mru;
- int hdr_len;
+ enum l2tp_pwtype pwtype;
struct l2tp_stats stats;
+ struct hlist_node global_hlist; /* Global hash list node */
+ int (*build_header)(struct l2tp_session *session, void *buf);
void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
void (*session_close)(struct l2tp_session *session);
void (*ref)(struct l2tp_session *session);
@@ -134,7 +172,6 @@ struct l2tp_tunnel {
char name[20]; /* for logging */
int debug; /* bitmask of debug message
* categories */
- int hdr_len;
struct l2tp_stats stats;
struct list_head list; /* Keep a list of all tunnels */
@@ -182,7 +219,7 @@ out:
return tunnel;
}
-extern struct l2tp_session *l2tp_session_find(struct l2tp_tunnel *tunnel, u32 session_id);
+extern struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id);
extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth, int *skipped);
extern struct l2tp_tunnel *l2tp_tunnel_find(struct net *net, u32 tunnel_id);
extern struct l2tp_session *l2tp_session_find_nth(struct l2tp_tunnel *tunnel, int nth, int *skipped);
@@ -191,14 +228,15 @@ extern int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_i
extern 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);
extern void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
extern void l2tp_session_free(struct l2tp_session *session);
+extern 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));
extern int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb, int (*payload_hook)(struct sk_buff *skb));
extern int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);
-extern void l2tp_build_l2tp_header(struct l2tp_session *session, void *buf);
extern int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, size_t data_len);
extern int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len);
extern void l2tp_tunnel_destruct(struct sock *sk);
extern void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);
+extern void l2tp_session_set_header_len(struct l2tp_session *session, int version);
/* Tunnel reference counts. Incremented per session that is added to
* the tunnel.
@@ -684,7 +684,7 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
/* Check that this session doesn't already exist */
error = -EEXIST;
- session = l2tp_session_find(tunnel, sp->pppol2tp.s_session);
+ session = l2tp_session_find(sock_net(sk), tunnel, sp->pppol2tp.s_session);
if (session != NULL)
goto end;
@@ -692,7 +692,6 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
* headers.
*/
cfg.mtu = cfg.mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
- cfg.hdr_len = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
cfg.debug = tunnel->debug;
/* Allocate and initialize a new session context. */
@@ -1016,7 +1015,7 @@ static int pppol2tp_tunnel_ioctl(struct l2tp_tunnel *tunnel,
if (stats.session_id != 0) {
/* resend to session ioctl handler */
struct l2tp_session *session =
- l2tp_session_find(tunnel, stats.session_id);
+ l2tp_session_find(sock_net(sk), tunnel, stats.session_id);
if (session != NULL)
err = pppol2tp_session_ioctl(session, cmd, arg);
else
The L2TPv3 protocol changes the layout of the L2TP packet header. Tunnel and session ids change from 16-bit to 32-bit values, data sequence numbers change from 16-bit to 24-bit values and PPP-specific fields are moved into protocol-specific subheaders. Although this patch introduces L2TPv3 protocol support, there are no userspace interfaces to create L2TPv3 sessions yet. Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/Kconfig | 25 ++ net/l2tp/l2tp_core.c | 576 ++++++++++++++++++++++++++++++++++++++------------ net/l2tp/l2tp_core.h | 54 ++++- net/l2tp/l2tp_ppp.c | 5 4 files changed, 510 insertions(+), 150 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html