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authorJames Chapman <jchapman@katalix.com>2010-04-02 06:19:00 +0000
committerDavid S. Miller <davem@davemloft.net>2010-04-03 14:56:04 -0700
commit0d76751fad7739014485ba5bd388d4f1b4fd4143 (patch)
tree25a4525bf6b2ec9f052f22ba98cdfd3ff3a86aa3 /net/l2tp/l2tp_core.c
parente0d4435f93905f517003cfa7328a36ea19788147 (diff)
l2tp: Add L2TPv3 IP encapsulation (no UDP) support
This patch adds a new L2TPIP socket family and modifies the core to handle the case where there is no UDP header in the L2TP packet. L2TP/IP uses IP protocol 115. Since L2TP/UDP and L2TP/IP packets differ in layout, the datapath packet handling code needs changes too. Userspace uses an L2TPIP socket instead of a UDP socket when IP encapsulation is required. We can't use raw sockets for this because the semantics of raw sockets don't lend themselves to the socket-per-tunnel model - we need to Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/l2tp/l2tp_core.c')
-rw-r--r--net/l2tp/l2tp_core.c163
1 files changed, 103 insertions, 60 deletions
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 0eee1a65f1b1..1739d04367e4 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -36,8 +36,10 @@
#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>
@@ -48,6 +50,7 @@
#include <net/ip.h>
#include <net/udp.h>
#include <net/xfrm.h>
+#include <net/protocol.h>
#include <asm/byteorder.h>
#include <asm/atomic.h>
@@ -849,15 +852,21 @@ static int l2tp_build_l2tpv2_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;
- /* Setup L2TP header. */
- *((__be16 *) bufp) = htons(flags);
- bufp += 2;
- *((__be16 *) bufp) = 0;
- bufp += 2;
+ /* 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) {
@@ -902,10 +911,11 @@ int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, size_t dat
if (session->debug & L2TP_MSG_DATA) {
int i;
- unsigned char *datap = skb->data + sizeof(struct udphdr);
+ 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 - sizeof(struct udphdr)); i++) {
+ for (i = 0; i < (len - uhlen); i++) {
printk(" %02X", *datap++);
if (i == 31) {
printk(" ...");
@@ -956,21 +966,23 @@ static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
{
int data_len = skb->len;
- struct sock *sk = session->tunnel->sock;
+ struct l2tp_tunnel *tunnel = session->tunnel;
+ struct sock *sk = tunnel->sock;
struct udphdr *uh;
- unsigned int udp_len;
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) +
- sizeof(struct udphdr) + hdr_len;
+ uhlen + hdr_len;
old_headroom = skb_headroom(skb);
if (skb_cow_head(skb, headroom))
goto abort;
@@ -981,18 +993,8 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
/* Setup L2TP header */
session->build_header(session, __skb_push(skb, hdr_len));
- udp_len = sizeof(struct udphdr) + hdr_len + data_len;
-
- /* Setup UDP header */
- inet = inet_sk(sk);
- __skb_push(skb, sizeof(*uh));
- skb_reset_transport_header(skb);
- uh = udp_hdr(skb);
- uh->source = inet->inet_sport;
- uh->dest = inet->inet_dport;
- uh->len = htons(udp_len);
- uh->check = 0;
+ /* 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);
@@ -1001,29 +1003,48 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
/* Get routing info from the tunnel socket */
skb_dst_drop(skb);
skb_dst_set(skb, dst_clone(__sk_dst_get(sk)));
- l2tp_skb_set_owner_w(skb, sk);
- /* Calculate UDP checksum if configured to do so */
- 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);
+ switch (tunnel->encap) {
+ case L2TP_ENCAPTYPE_UDP:
+ /* Setup UDP header */
+ inet = inet_sk(sk);
+ __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 (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, data_len);
abort:
@@ -1053,9 +1074,15 @@ void l2tp_tunnel_destruct(struct sock *sk)
/* Close all sessions */
l2tp_tunnel_closeall(tunnel);
- /* No longer an encapsulation socket. See net/ipv4/udp.c */
- (udp_sk(sk))->encap_type = 0;
- (udp_sk(sk))->encap_rcv = NULL;
+ 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;
@@ -1168,6 +1195,7 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
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.
@@ -1182,18 +1210,27 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
sk = sock->sk;
+ if (cfg != NULL)
+ encap = cfg->encap;
+
/* Quick sanity checks */
- 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;
- }
- err = -EAFNOSUPPORT;
- if (sock->ops->family != AF_INET) {
- printk(KERN_ERR "tunl %hu: fd %d wrong family, got %d, expected %d\n",
- tunnel_id, fd, sock->ops->family, AF_INET);
- goto err;
+ 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 */
@@ -1223,12 +1260,16 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
tunnel->l2tp_net = net;
pn = l2tp_pernet(net);
- if (cfg)
+ if (cfg != NULL)
tunnel->debug = cfg->debug;
/* 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;
+ 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;
+ }
sk->sk_user_data = tunnel;
@@ -1318,7 +1359,9 @@ void l2tp_session_set_header_len(struct l2tp_session *session, int version)
if (session->send_seq)
session->hdr_len += 4;
} else {
- session->hdr_len = 8 + session->cookie_len + session->l2specific_len + session->offset;
+ session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset;
+ if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
+ session->hdr_len += 4;
}
}