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l2tp: Add L2TPv3 protocol support

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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>
Reviewed-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
James Chapman
2010-04-02 06:18:49 +00:00
committed by David S. Miller
parent 9345471bca
commit f7faffa3ff
4 changed files with 484 additions and 148 deletions
Download Patch File Download Diff File Expand all files Collapse all files

532
net/l2tp/l2tp_core.c
View File

@ -65,6 +65,7 @@
#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
@ -85,7 +86,7 @@
/* 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;
@ -101,6 +102,8 @@ 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)
@ -110,6 +113,40 @@ 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)
{
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;
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
@ -124,13 +161,20 @@ 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) {
@ -218,7 +262,7 @@ 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) {
@ -259,6 +303,11 @@ 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);
}
@ -291,8 +340,8 @@ 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));
@ -306,8 +355,8 @@ 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));
@ -352,100 +401,73 @@ 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
@ -455,6 +477,18 @@ 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.
*
@ -464,21 +498,40 @@ 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,
@ -489,6 +542,7 @@ 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.
@ -512,6 +566,7 @@ 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. "
@ -521,11 +576,19 @@ 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))
@ -564,8 +627,8 @@ 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));
@ -586,7 +649,7 @@ 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++;
@ -596,6 +659,111 @@ 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;
@ -651,11 +819,11 @@ 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;
@ -671,19 +839,51 @@ 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)
{
@ -694,7 +894,7 @@ 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,
@ -780,7 +980,7 @@ 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 */
@ -791,7 +991,6 @@ 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));
@ -911,6 +1110,14 @@ 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);
@ -997,9 +1204,6 @@ 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;
@ -1077,6 +1281,15 @@ 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);
@ -1095,6 +1308,22 @@ 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;
@ -1106,6 +1335,7 @@ 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);
@ -1113,20 +1343,36 @@ 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.
*/
@ -1142,6 +1388,16 @@ 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);
@ -1159,6 +1415,7 @@ static __net_init int l2tp_init_net(struct net *net)
{
struct l2tp_net *pn;
int err;
int hash;
pn = kzalloc(sizeof(*pn), GFP_KERNEL);
if (!pn)
@ -1167,6 +1424,11 @@ 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;