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>
This commit is contained in:
James Chapman
David S. Miller
parent
e0d4435f93
commit
0d76751fad
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@ -0,0 +1,38 @@
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/*
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* L2TP-over-IP socket for L2TPv3.
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*
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* Author: James Chapman <jchapman@katalix.com>
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*/
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#ifndef _LINUX_L2TP_H_
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#define _LINUX_L2TP_H_
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#include <linux/types.h>
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#ifdef __KERNEL__
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#include <linux/socket.h>
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#include <linux/in.h>
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#endif
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#define IPPROTO_L2TP 115
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/**
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* struct sockaddr_l2tpip - the sockaddr structure for L2TP-over-IP sockets
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* @l2tp_family: address family number AF_L2TPIP.
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* @l2tp_addr: protocol specific address information
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* @l2tp_conn_id: connection id of tunnel
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*/
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struct sockaddr_l2tpip {
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/* The first fields must match struct sockaddr_in */
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sa_family_t l2tp_family; /* AF_INET */
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__be16 l2tp_unused; /* INET port number (unused) */
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struct in_addr l2tp_addr; /* Internet address */
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__u32 l2tp_conn_id; /* Connection ID of tunnel */
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/* Pad to size of `struct sockaddr'. */
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unsigned char __pad[sizeof(struct sockaddr) - sizeof(sa_family_t) -
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sizeof(__be16) - sizeof(struct in_addr) -
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sizeof(__u32)];
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};
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#endif
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@ -51,3 +51,20 @@ config L2TP_V3
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If you are connecting to L2TPv3 equipment, or you want to
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tunnel raw ethernet frames using L2TP, say Y here. If
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unsure, say N.
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config L2TP_IP
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tristate "L2TP IP encapsulation for L2TPv3"
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depends on L2TP_V3
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help
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Support for L2TP-over-IP socket family.
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The L2TPv3 protocol defines two possible encapsulations for
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L2TP frames, namely UDP and plain IP (without UDP). This
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driver provides a new L2TPIP socket family with which
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userspace L2TPv3 daemons may create L2TP/IP tunnel sockets
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when UDP encapsulation is not required. When L2TP is carried
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in IP packets, it used IP protocol number 115, so this port
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must be enabled in firewalls.
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To compile this driver as a module, choose M here. The module
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will be called l2tp_ip.
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@ -6,3 +6,4 @@ obj-$(CONFIG_L2TP) += l2tp_core.o
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# Build l2tp as modules if L2TP is M
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obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_PPPOL2TP)) += l2tp_ppp.o
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obj-$(subst y,$(CONFIG_L2TP),$(CONFIG_L2TP_IP)) += l2tp_ip.o
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@ -36,8 +36,10 @@
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#include <linux/inetdevice.h>
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#include <linux/skbuff.h>
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#include <linux/init.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/udp.h>
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#include <linux/l2tp.h>
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#include <linux/hash.h>
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#include <linux/sort.h>
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#include <linux/file.h>
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@ -48,6 +50,7 @@
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#include <net/ip.h>
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#include <net/udp.h>
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#include <net/xfrm.h>
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#include <net/protocol.h>
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#include <asm/byteorder.h>
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#include <asm/atomic.h>
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@ -849,15 +852,21 @@ static int l2tp_build_l2tpv2_header(struct l2tp_session *session, void *buf)
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static int l2tp_build_l2tpv3_header(struct l2tp_session *session, void *buf)
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{
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struct l2tp_tunnel *tunnel = session->tunnel;
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char *bufp = buf;
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char *optr = bufp;
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u16 flags = L2TP_HDR_VER_3;
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/* Setup L2TP header. */
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*((__be16 *) bufp) = htons(flags);
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bufp += 2;
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*((__be16 *) bufp) = 0;
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bufp += 2;
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/* Setup L2TP header. The header differs slightly for UDP and
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* IP encapsulations. For UDP, there is 4 bytes of flags.
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*/
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if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
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u16 flags = L2TP_HDR_VER_3;
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*((__be16 *) bufp) = htons(flags);
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bufp += 2;
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*((__be16 *) bufp) = 0;
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bufp += 2;
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}
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*((__be32 *) bufp) = htonl(session->peer_session_id);
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bufp += 4;
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if (session->cookie_len) {
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@ -902,10 +911,11 @@ int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb, size_t dat
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if (session->debug & L2TP_MSG_DATA) {
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int i;
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unsigned char *datap = skb->data + sizeof(struct udphdr);
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int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
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unsigned char *datap = skb->data + uhlen;
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printk(KERN_DEBUG "%s: xmit:", session->name);
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for (i = 0; i < (len - sizeof(struct udphdr)); i++) {
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for (i = 0; i < (len - uhlen); i++) {
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printk(" %02X", *datap++);
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if (i == 31) {
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printk(" ...");
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@ -956,21 +966,23 @@ static inline void l2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
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int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len)
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{
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int data_len = skb->len;
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struct sock *sk = session->tunnel->sock;
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struct l2tp_tunnel *tunnel = session->tunnel;
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struct sock *sk = tunnel->sock;
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struct udphdr *uh;
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unsigned int udp_len;
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struct inet_sock *inet;
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__wsum csum;
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int old_headroom;
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int new_headroom;
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int headroom;
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int uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
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int udp_len;
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/* Check that there's enough headroom in the skb to insert IP,
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* UDP and L2TP headers. If not enough, expand it to
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* make room. Adjust truesize.
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*/
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headroom = NET_SKB_PAD + sizeof(struct iphdr) +
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sizeof(struct udphdr) + hdr_len;
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uhlen + hdr_len;
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old_headroom = skb_headroom(skb);
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if (skb_cow_head(skb, headroom))
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goto abort;
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@ -981,18 +993,8 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
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/* Setup L2TP header */
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session->build_header(session, __skb_push(skb, hdr_len));
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udp_len = sizeof(struct udphdr) + hdr_len + data_len;
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/* Setup UDP header */
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inet = inet_sk(sk);
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__skb_push(skb, sizeof(*uh));
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skb_reset_transport_header(skb);
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uh = udp_hdr(skb);
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uh->source = inet->inet_sport;
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uh->dest = inet->inet_dport;
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uh->len = htons(udp_len);
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uh->check = 0;
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/* Reset skb netfilter state */
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memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
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IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
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IPSKB_REROUTED);
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@ -1001,29 +1003,48 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
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/* Get routing info from the tunnel socket */
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skb_dst_drop(skb);
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skb_dst_set(skb, dst_clone(__sk_dst_get(sk)));
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l2tp_skb_set_owner_w(skb, sk);
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/* Calculate UDP checksum if configured to do so */
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if (sk->sk_no_check == UDP_CSUM_NOXMIT)
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skb->ip_summed = CHECKSUM_NONE;
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else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
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(!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
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skb->ip_summed = CHECKSUM_COMPLETE;
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csum = skb_checksum(skb, 0, udp_len, 0);
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uh->check = csum_tcpudp_magic(inet->inet_saddr,
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inet->inet_daddr,
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udp_len, IPPROTO_UDP, csum);
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if (uh->check == 0)
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uh->check = CSUM_MANGLED_0;
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} else {
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skb->ip_summed = CHECKSUM_PARTIAL;
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skb->csum_start = skb_transport_header(skb) - skb->head;
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skb->csum_offset = offsetof(struct udphdr, check);
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uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
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inet->inet_daddr,
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udp_len, IPPROTO_UDP, 0);
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switch (tunnel->encap) {
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case L2TP_ENCAPTYPE_UDP:
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/* Setup UDP header */
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inet = inet_sk(sk);
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__skb_push(skb, sizeof(*uh));
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skb_reset_transport_header(skb);
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uh = udp_hdr(skb);
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uh->source = inet->inet_sport;
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uh->dest = inet->inet_dport;
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udp_len = uhlen + hdr_len + data_len;
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uh->len = htons(udp_len);
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uh->check = 0;
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/* Calculate UDP checksum if configured to do so */
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if (sk->sk_no_check == UDP_CSUM_NOXMIT)
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skb->ip_summed = CHECKSUM_NONE;
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else if ((skb_dst(skb) && skb_dst(skb)->dev) &&
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(!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM))) {
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skb->ip_summed = CHECKSUM_COMPLETE;
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csum = skb_checksum(skb, 0, udp_len, 0);
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uh->check = csum_tcpudp_magic(inet->inet_saddr,
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inet->inet_daddr,
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udp_len, IPPROTO_UDP, csum);
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if (uh->check == 0)
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uh->check = CSUM_MANGLED_0;
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} else {
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skb->ip_summed = CHECKSUM_PARTIAL;
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skb->csum_start = skb_transport_header(skb) - skb->head;
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skb->csum_offset = offsetof(struct udphdr, check);
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uh->check = ~csum_tcpudp_magic(inet->inet_saddr,
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inet->inet_daddr,
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udp_len, IPPROTO_UDP, 0);
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}
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break;
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case L2TP_ENCAPTYPE_IP:
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break;
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}
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l2tp_skb_set_owner_w(skb, sk);
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l2tp_xmit_core(session, skb, data_len);
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abort:
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@ -1053,9 +1074,15 @@ void l2tp_tunnel_destruct(struct sock *sk)
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/* Close all sessions */
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l2tp_tunnel_closeall(tunnel);
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/* No longer an encapsulation socket. See net/ipv4/udp.c */
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(udp_sk(sk))->encap_type = 0;
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(udp_sk(sk))->encap_rcv = NULL;
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switch (tunnel->encap) {
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case L2TP_ENCAPTYPE_UDP:
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/* No longer an encapsulation socket. See net/ipv4/udp.c */
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(udp_sk(sk))->encap_type = 0;
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(udp_sk(sk))->encap_rcv = NULL;
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break;
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case L2TP_ENCAPTYPE_IP:
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break;
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}
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/* Remove hooks into tunnel socket */
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tunnel->sock = NULL;
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@ -1168,6 +1195,7 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
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struct socket *sock = NULL;
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struct sock *sk = NULL;
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struct l2tp_net *pn;
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enum l2tp_encap_type encap = L2TP_ENCAPTYPE_UDP;
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/* Get the tunnel socket from the fd, which was opened by
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* the userspace L2TP daemon.
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@ -1182,18 +1210,27 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
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sk = sock->sk;
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if (cfg != NULL)
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encap = cfg->encap;
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/* Quick sanity checks */
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err = -EPROTONOSUPPORT;
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if (sk->sk_protocol != IPPROTO_UDP) {
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printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
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tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
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goto err;
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}
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err = -EAFNOSUPPORT;
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if (sock->ops->family != AF_INET) {
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printk(KERN_ERR "tunl %hu: fd %d wrong family, got %d, expected %d\n",
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tunnel_id, fd, sock->ops->family, AF_INET);
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goto err;
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switch (encap) {
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case L2TP_ENCAPTYPE_UDP:
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err = -EPROTONOSUPPORT;
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if (sk->sk_protocol != IPPROTO_UDP) {
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printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
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tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
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goto err;
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}
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break;
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case L2TP_ENCAPTYPE_IP:
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err = -EPROTONOSUPPORT;
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if (sk->sk_protocol != IPPROTO_L2TP) {
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printk(KERN_ERR "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
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tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);
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goto err;
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}
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break;
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}
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/* Check if this socket has already been prepped */
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@ -1223,12 +1260,16 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
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tunnel->l2tp_net = net;
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pn = l2tp_pernet(net);
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if (cfg)
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if (cfg != NULL)
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tunnel->debug = cfg->debug;
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/* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
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udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
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udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
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tunnel->encap = encap;
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if (encap == L2TP_ENCAPTYPE_UDP) {
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/* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
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udp_sk(sk)->encap_type = UDP_ENCAP_L2TPINUDP;
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udp_sk(sk)->encap_rcv = l2tp_udp_encap_recv;
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}
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sk->sk_user_data = tunnel;
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@ -1318,7 +1359,9 @@ void l2tp_session_set_header_len(struct l2tp_session *session, int version)
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if (session->send_seq)
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session->hdr_len += 4;
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} else {
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session->hdr_len = 8 + session->cookie_len + session->l2specific_len + session->offset;
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session->hdr_len = 4 + session->cookie_len + session->l2specific_len + session->offset;
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if (session->tunnel->encap == L2TP_ENCAPTYPE_UDP)
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session->hdr_len += 4;
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}
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}
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@ -48,6 +48,11 @@ enum l2tp_l2spec_type {
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L2TP_L2SPECTYPE_DEFAULT,
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};
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enum l2tp_encap_type {
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L2TP_ENCAPTYPE_UDP,
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L2TP_ENCAPTYPE_IP,
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};
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struct sk_buff;
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struct l2tp_stats {
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@ -155,6 +160,7 @@ struct l2tp_session {
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struct l2tp_tunnel_cfg {
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int debug; /* bitmask of debug message
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* categories */
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enum l2tp_encap_type encap;
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};
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struct l2tp_tunnel {
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@ -170,6 +176,7 @@ struct l2tp_tunnel {
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char name[20]; /* for logging */
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int debug; /* bitmask of debug message
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* categories */
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enum l2tp_encap_type encap;
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struct l2tp_stats stats;
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struct list_head list; /* Keep a list of all tunnels */
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@ -0,0 +1,679 @@
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/*
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* L2TPv3 IP encapsulation support
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*
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* Copyright (c) 2008,2009,2010 Katalix Systems Ltd
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/icmp.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/random.h>
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#include <linux/socket.h>
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#include <linux/l2tp.h>
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#include <linux/in.h>
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#include <net/sock.h>
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#include <net/ip.h>
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#include <net/icmp.h>
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#include <net/udp.h>
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#include <net/inet_common.h>
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#include <net/inet_hashtables.h>
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#include <net/tcp_states.h>
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#include <net/protocol.h>
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#include <net/xfrm.h>
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#include "l2tp_core.h"
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struct l2tp_ip_sock {
|
||||
/* inet_sock has to be the first member of l2tp_ip_sock */
|
||||
struct inet_sock inet;
|
||||
|
||||
__u32 conn_id;
|
||||
__u32 peer_conn_id;
|
||||
|
||||
__u64 tx_packets;
|
||||
__u64 tx_bytes;
|
||||
__u64 tx_errors;
|
||||
__u64 rx_packets;
|
||||
__u64 rx_bytes;
|
||||
__u64 rx_errors;
|
||||
};
|
||||
|
||||
static DEFINE_RWLOCK(l2tp_ip_lock);
|
||||
static struct hlist_head l2tp_ip_table;
|
||||
static struct hlist_head l2tp_ip_bind_table;
|
||||
|
||||
static inline struct l2tp_ip_sock *l2tp_ip_sk(const struct sock *sk)
|
||||
{
|
||||
return (struct l2tp_ip_sock *)sk;
|
||||
}
|
||||
|
||||
static struct sock *__l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
|
||||
{
|
||||
struct hlist_node *node;
|
||||
struct sock *sk;
|
||||
|
||||
sk_for_each_bound(sk, node, &l2tp_ip_bind_table) {
|
||||
struct inet_sock *inet = inet_sk(sk);
|
||||
struct l2tp_ip_sock *l2tp = l2tp_ip_sk(sk);
|
||||
|
||||
if (l2tp == NULL)
|
||||
continue;
|
||||
|
||||
if ((l2tp->conn_id == tunnel_id) &&
|
||||
#ifdef CONFIG_NET_NS
|
||||
(sk->sk_net == net) &&
|
||||
#endif
|
||||
!(inet->inet_rcv_saddr && inet->inet_rcv_saddr != laddr) &&
|
||||
!(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
|
||||
goto found;
|
||||
}
|
||||
|
||||
sk = NULL;
|
||||
found:
|
||||
return sk;
|
||||
}
|
||||
|
||||
static inline struct sock *l2tp_ip_bind_lookup(struct net *net, __be32 laddr, int dif, u32 tunnel_id)
|
||||
{
|
||||
struct sock *sk = __l2tp_ip_bind_lookup(net, laddr, dif, tunnel_id);
|
||||
if (sk)
|
||||
sock_hold(sk);
|
||||
|
||||
return sk;
|
||||
}
|
||||
|
||||
/* When processing receive frames, there are two cases to
|
||||
* consider. Data frames consist of a non-zero session-id and an
|
||||
* optional cookie. Control frames consist of a regular L2TP header
|
||||
* preceded by 32-bits of zeros.
|
||||
*
|
||||
* 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 Control Message 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
|
||||
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
||||
* | (32 bits of zeros) |
|
||||
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
||||
* |T|L|x|x|S|x|x|x|x|x|x|x| Ver | Length |
|
||||
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
||||
* | Control Connection ID |
|
||||
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
||||
* | Ns | Nr |
|
||||
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
||||
*
|
||||
* All control frames are passed to userspace.
|
||||
*/
|
||||
static int l2tp_ip_recv(struct sk_buff *skb)
|
||||
{
|
||||
struct sock *sk;
|
||||
u32 session_id;
|
||||
u32 tunnel_id;
|
||||
unsigned char *ptr, *optr;
|
||||
struct l2tp_session *session;
|
||||
struct l2tp_tunnel *tunnel = NULL;
|
||||
int length;
|
||||
int offset;
|
||||
|
||||
/* Point to L2TP header */
|
||||
optr = ptr = skb->data;
|
||||
|
||||
if (!pskb_may_pull(skb, 4))
|
||||
goto discard;
|
||||
|
||||
session_id = ntohl(*((__be32 *) ptr));
|
||||
ptr += 4;
|
||||
|
||||
/* RFC3931: L2TP/IP packets have the first 4 bytes containing
|
||||
* the session_id. If it is 0, the packet is a L2TP control
|
||||
* frame and the session_id value can be discarded.
|
||||
*/
|
||||
if (session_id == 0) {
|
||||
__skb_pull(skb, 4);
|
||||
goto pass_up;
|
||||
}
|
||||
|
||||
/* Ok, this is a data packet. Lookup the session. */
|
||||
session = l2tp_session_find(&init_net, NULL, session_id);
|
||||
if (session == NULL)
|
||||
goto discard;
|
||||
|
||||
tunnel = session->tunnel;
|
||||
if (tunnel == NULL)
|
||||
goto discard;
|
||||
|
||||
/* Trace packet contents, if enabled */
|
||||
if (tunnel->debug & L2TP_MSG_DATA) {
|
||||
length = min(32u, skb->len);
|
||||
if (!pskb_may_pull(skb, length))
|
||||
goto discard;
|
||||
|
||||
printk(KERN_DEBUG "%s: ip recv: ", tunnel->name);
|
||||
|
||||
offset = 0;
|
||||
do {
|
||||
printk(" %02X", ptr[offset]);
|
||||
} while (++offset < length);
|
||||
|
||||
printk("\n");
|
||||
}
|
||||
|
||||
l2tp_recv_common(session, skb, ptr, optr, 0, skb->len, tunnel->recv_payload_hook);
|
||||
|
||||
return 0;
|
||||
|
||||
pass_up:
|
||||
/* Get the tunnel_id from the L2TP header */
|
||||
if (!pskb_may_pull(skb, 12))
|
||||
goto discard;
|
||||
|
||||
if ((skb->data[0] & 0xc0) != 0xc0)
|
||||
goto discard;
|
||||
|
||||
tunnel_id = ntohl(*(__be32 *) &skb->data[4]);
|
||||
tunnel = l2tp_tunnel_find(&init_net, tunnel_id);
|
||||
if (tunnel != NULL)
|
||||
sk = tunnel->sock;
|
||||
else {
|
||||
struct iphdr *iph = (struct iphdr *) skb_network_header(skb);
|
||||
|
||||
read_lock_bh(&l2tp_ip_lock);
|
||||
sk = __l2tp_ip_bind_lookup(&init_net, iph->daddr, 0, tunnel_id);
|
||||
read_unlock_bh(&l2tp_ip_lock);
|
||||
}
|
||||
|
||||
if (sk == NULL)
|
||||
goto discard;
|
||||
|
||||
sock_hold(sk);
|
||||
|
||||
if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
|
||||
goto discard_put;
|
||||
|
||||
nf_reset(skb);
|
||||
|
||||
return sk_receive_skb(sk, skb, 1);
|
||||
|
||||
discard_put:
|
||||
sock_put(sk);
|
||||
|
||||
discard:
|
||||
kfree_skb(skb);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int l2tp_ip_open(struct sock *sk)
|
||||
{
|
||||
/* Prevent autobind. We don't have ports. */
|
||||
inet_sk(sk)->inet_num = IPPROTO_L2TP;
|
||||
|
||||
write_lock_bh(&l2tp_ip_lock);
|
||||
sk_add_node(sk, &l2tp_ip_table);
|
||||
write_unlock_bh(&l2tp_ip_lock);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void l2tp_ip_close(struct sock *sk, long timeout)
|
||||
{
|
||||
write_lock_bh(&l2tp_ip_lock);
|
||||
hlist_del_init(&sk->sk_bind_node);
|
||||
hlist_del_init(&sk->sk_node);
|
||||
write_unlock_bh(&l2tp_ip_lock);
|
||||
sk_common_release(sk);
|
||||
}
|
||||
|
||||
static void l2tp_ip_destroy_sock(struct sock *sk)
|
||||
{
|
||||
struct sk_buff *skb;
|
||||
|
||||
while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL)
|
||||
kfree_skb(skb);
|
||||
|
||||
sk_refcnt_debug_dec(sk);
|
||||
}
|
||||
|
||||
static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
|
||||
{
|
||||
struct inet_sock *inet = inet_sk(sk);
|
||||
struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
|
||||
int ret = -EINVAL;
|
||||
int chk_addr_ret;
|
||||
|
||||
ret = -EADDRINUSE;
|
||||
read_lock_bh(&l2tp_ip_lock);
|
||||
if (__l2tp_ip_bind_lookup(&init_net, addr->l2tp_addr.s_addr, sk->sk_bound_dev_if, addr->l2tp_conn_id))
|
||||
goto out_in_use;
|
||||
|
||||
read_unlock_bh(&l2tp_ip_lock);
|
||||
|
||||
lock_sock(sk);
|
||||
if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
|
||||
goto out;
|
||||
|
||||
chk_addr_ret = inet_addr_type(&init_net, addr->l2tp_addr.s_addr);
|
||||
ret = -EADDRNOTAVAIL;
|
||||
if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
|
||||
chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
|
||||
goto out;
|
||||
|
||||
inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
|
||||
if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
|
||||
inet->inet_saddr = 0; /* Use device */
|
||||
sk_dst_reset(sk);
|
||||
|
||||
l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;
|
||||
|
||||
write_lock_bh(&l2tp_ip_lock);
|
||||
sk_add_bind_node(sk, &l2tp_ip_bind_table);
|
||||
sk_del_node_init(sk);
|
||||
write_unlock_bh(&l2tp_ip_lock);
|
||||
ret = 0;
|
||||
out:
|
||||
release_sock(sk);
|
||||
|
||||
return ret;
|
||||
|
||||
out_in_use:
|
||||
read_unlock_bh(&l2tp_ip_lock);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int l2tp_ip_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
|
||||
{
|
||||
int rc;
|
||||
struct inet_sock *inet = inet_sk(sk);
|
||||
struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *) uaddr;
|
||||
struct rtable *rt;
|
||||
__be32 saddr;
|
||||
int oif;
|
||||
|
||||
rc = -EINVAL;
|
||||
if (addr_len < sizeof(*lsa))
|
||||
goto out;
|
||||
|
||||
rc = -EAFNOSUPPORT;
|
||||
if (lsa->l2tp_family != AF_INET)
|
||||
goto out;
|
||||
|
||||
sk_dst_reset(sk);
|
||||
|
||||
oif = sk->sk_bound_dev_if;
|
||||
saddr = inet->inet_saddr;
|
||||
|
||||
rc = -EINVAL;
|
||||
if (ipv4_is_multicast(lsa->l2tp_addr.s_addr))
|
||||
goto out;
|
||||
|
||||
rc = ip_route_connect(&rt, lsa->l2tp_addr.s_addr, saddr,
|
||||
RT_CONN_FLAGS(sk), oif,
|
||||
IPPROTO_L2TP,
|
||||
0, 0, sk, 1);
|
||||
if (rc) {
|
||||
if (rc == -ENETUNREACH)
|
||||
IP_INC_STATS_BH(&init_net, IPSTATS_MIB_OUTNOROUTES);
|
||||
goto out;
|
||||
}
|
||||
|
||||
rc = -ENETUNREACH;
|
||||
if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
|
||||
ip_rt_put(rt);
|
||||
goto out;
|
||||
}
|
||||
|
||||
l2tp_ip_sk(sk)->peer_conn_id = lsa->l2tp_conn_id;
|
||||
|
||||
if (!inet->inet_saddr)
|
||||
inet->inet_saddr = rt->rt_src;
|
||||
if (!inet->inet_rcv_saddr)
|
||||
inet->inet_rcv_saddr = rt->rt_src;
|
||||
inet->inet_daddr = rt->rt_dst;
|
||||
sk->sk_state = TCP_ESTABLISHED;
|
||||
inet->inet_id = jiffies;
|
||||
|
||||
sk_dst_set(sk, &rt->u.dst);
|
||||
|
||||
write_lock_bh(&l2tp_ip_lock);
|
||||
hlist_del_init(&sk->sk_bind_node);
|
||||
sk_add_bind_node(sk, &l2tp_ip_bind_table);
|
||||
write_unlock_bh(&l2tp_ip_lock);
|
||||
|
||||
rc = 0;
|
||||
out:
|
||||
return rc;
|
||||
}
|
||||
|
||||
static int l2tp_ip_getname(struct socket *sock, struct sockaddr *uaddr,
|
||||
int *uaddr_len, int peer)
|
||||
{
|
||||
struct sock *sk = sock->sk;
|
||||
struct inet_sock *inet = inet_sk(sk);
|
||||
struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
|
||||
struct sockaddr_l2tpip *lsa = (struct sockaddr_l2tpip *)uaddr;
|
||||
|
||||
memset(lsa, 0, sizeof(*lsa));
|
||||
lsa->l2tp_family = AF_INET;
|
||||
if (peer) {
|
||||
if (!inet->inet_dport)
|
||||
return -ENOTCONN;
|
||||
lsa->l2tp_conn_id = lsk->peer_conn_id;
|
||||
lsa->l2tp_addr.s_addr = inet->inet_daddr;
|
||||
} else {
|
||||
__be32 addr = inet->inet_rcv_saddr;
|
||||
if (!addr)
|
||||
addr = inet->inet_saddr;
|
||||
lsa->l2tp_conn_id = lsk->conn_id;
|
||||
lsa->l2tp_addr.s_addr = addr;
|
||||
}
|
||||
*uaddr_len = sizeof(*lsa);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int l2tp_ip_backlog_recv(struct sock *sk, struct sk_buff *skb)
|
||||
{
|
||||
int rc;
|
||||
|
||||
if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
|
||||
goto drop;
|
||||
|
||||
nf_reset(skb);
|
||||
|
||||
/* Charge it to the socket, dropping if the queue is full. */
|
||||
rc = sock_queue_rcv_skb(sk, skb);
|
||||
if (rc < 0)
|
||||
goto drop;
|
||||
|
||||
return 0;
|
||||
|
||||
drop:
|
||||
IP_INC_STATS(&init_net, IPSTATS_MIB_INDISCARDS);
|
||||
kfree_skb(skb);
|
||||
return -1;
|
||||
}
|
||||
|
||||
/* Userspace will call sendmsg() on the tunnel socket to send L2TP
|
||||
* control frames.
|
||||
*/
|
||||
static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len)
|
||||
{
|
||||
struct sk_buff *skb;
|
||||
int rc;
|
||||
struct l2tp_ip_sock *lsa = l2tp_ip_sk(sk);
|
||||
struct inet_sock *inet = inet_sk(sk);
|
||||
struct ip_options *opt = inet->opt;
|
||||
struct rtable *rt = NULL;
|
||||
int connected = 0;
|
||||
__be32 daddr;
|
||||
|
||||
if (sock_flag(sk, SOCK_DEAD))
|
||||
return -ENOTCONN;
|
||||
|
||||
/* Get and verify the address. */
|
||||
if (msg->msg_name) {
|
||||
struct sockaddr_l2tpip *lip = (struct sockaddr_l2tpip *) msg->msg_name;
|
||||
if (msg->msg_namelen < sizeof(*lip))
|
||||
return -EINVAL;
|
||||
|
||||
if (lip->l2tp_family != AF_INET) {
|
||||
if (lip->l2tp_family != AF_UNSPEC)
|
||||
return -EAFNOSUPPORT;
|
||||
}
|
||||
|
||||
daddr = lip->l2tp_addr.s_addr;
|
||||
} else {
|
||||
if (sk->sk_state != TCP_ESTABLISHED)
|
||||
return -EDESTADDRREQ;
|
||||
|
||||
daddr = inet->inet_daddr;
|
||||
connected = 1;
|
||||
}
|
||||
|
||||
/* Allocate a socket buffer */
|
||||
rc = -ENOMEM;
|
||||
skb = sock_wmalloc(sk, 2 + NET_SKB_PAD + sizeof(struct iphdr) +
|
||||
4 + len, 0, GFP_KERNEL);
|
||||
if (!skb)
|
||||
goto error;
|
||||
|
||||
/* Reserve space for headers, putting IP header on 4-byte boundary. */
|
||||
skb_reserve(skb, 2 + NET_SKB_PAD);
|
||||
skb_reset_network_header(skb);
|
||||
skb_reserve(skb, sizeof(struct iphdr));
|
||||
skb_reset_transport_header(skb);
|
||||
|
||||
/* Insert 0 session_id */
|
||||
*((__be32 *) skb_put(skb, 4)) = 0;
|
||||
|
||||
/* Copy user data into skb */
|
||||
rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
|
||||
if (rc < 0) {
|
||||
kfree_skb(skb);
|
||||
goto error;
|
||||
}
|
||||
|
||||
if (connected)
|
||||
rt = (struct rtable *) __sk_dst_check(sk, 0);
|
||||
|
||||
if (rt == NULL) {
|
||||
/* Use correct destination address if we have options. */
|
||||
if (opt && opt->srr)
|
||||
daddr = opt->faddr;
|
||||
|
||||
{
|
||||
struct flowi fl = { .oif = sk->sk_bound_dev_if,
|
||||
.nl_u = { .ip4_u = {
|
||||
.daddr = daddr,
|
||||
.saddr = inet->inet_saddr,
|
||||
.tos = RT_CONN_FLAGS(sk) } },
|
||||
.proto = sk->sk_protocol,
|
||||
.flags = inet_sk_flowi_flags(sk),
|
||||
.uli_u = { .ports = {
|
||||
.sport = inet->inet_sport,
|
||||
.dport = inet->inet_dport } } };
|
||||
|
||||
/* If this fails, retransmit mechanism of transport layer will
|
||||
* keep trying until route appears or the connection times
|
||||
* itself out.
|
||||
*/
|
||||
security_sk_classify_flow(sk, &fl);
|
||||
if (ip_route_output_flow(sock_net(sk), &rt, &fl, sk, 0))
|
||||
goto no_route;
|
||||
}
|
||||
sk_setup_caps(sk, &rt->u.dst);
|
||||
}
|
||||
skb_dst_set(skb, dst_clone(&rt->u.dst));
|
||||
|
||||
/* Queue the packet to IP for output */
|
||||
rc = ip_queue_xmit(skb, 0);
|
||||
|
||||
error:
|
||||
/* Update stats */
|
||||
if (rc >= 0) {
|
||||
lsa->tx_packets++;
|
||||
lsa->tx_bytes += len;
|
||||
rc = len;
|
||||
} else {
|
||||
lsa->tx_errors++;
|
||||
}
|
||||
|
||||
return rc;
|
||||
|
||||
no_route:
|
||||
IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
|
||||
kfree_skb(skb);
|
||||
return -EHOSTUNREACH;
|
||||
}
|
||||
|
||||
static int l2tp_ip_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
|
||||
size_t len, int noblock, int flags, int *addr_len)
|
||||
{
|
||||
struct inet_sock *inet = inet_sk(sk);
|
||||
struct l2tp_ip_sock *lsk = l2tp_ip_sk(sk);
|
||||
size_t copied = 0;
|
||||
int err = -EOPNOTSUPP;
|
||||
struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
|
||||
struct sk_buff *skb;
|
||||
|
||||
if (flags & MSG_OOB)
|
||||
goto out;
|
||||
|
||||
if (addr_len)
|
||||
*addr_len = sizeof(*sin);
|
||||
|
||||
skb = skb_recv_datagram(sk, flags, noblock, &err);
|
||||
if (!skb)
|
||||
goto out;
|
||||
|
||||
copied = skb->len;
|
||||
if (len < copied) {
|
||||
msg->msg_flags |= MSG_TRUNC;
|
||||
copied = len;
|
||||
}
|
||||
|
||||
err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
|
||||
if (err)
|
||||
goto done;
|
||||
|
||||
sock_recv_timestamp(msg, sk, skb);
|
||||
|
||||
/* Copy the address. */
|
||||
if (sin) {
|
||||
sin->sin_family = AF_INET;
|
||||
sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
|
||||
sin->sin_port = 0;
|
||||
memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
|
||||
}
|
||||
if (inet->cmsg_flags)
|
||||
ip_cmsg_recv(msg, skb);
|
||||
if (flags & MSG_TRUNC)
|
||||
copied = skb->len;
|
||||
done:
|
||||
skb_free_datagram(sk, skb);
|
||||
out:
|
||||
if (err) {
|
||||
lsk->rx_errors++;
|
||||
return err;
|
||||
}
|
||||
|
||||
lsk->rx_packets++;
|
||||
lsk->rx_bytes += copied;
|
||||
|
||||
return copied;
|
||||
}
|
||||
|
||||
struct proto l2tp_ip_prot = {
|
||||
.name = "L2TP/IP",
|
||||
.owner = THIS_MODULE,
|
||||
.init = l2tp_ip_open,
|
||||
.close = l2tp_ip_close,
|
||||
.bind = l2tp_ip_bind,
|
||||
.connect = l2tp_ip_connect,
|
||||
.disconnect = udp_disconnect,
|
||||
.ioctl = udp_ioctl,
|
||||
.destroy = l2tp_ip_destroy_sock,
|
||||
.setsockopt = ip_setsockopt,
|
||||
.getsockopt = ip_getsockopt,
|
||||
.sendmsg = l2tp_ip_sendmsg,
|
||||
.recvmsg = l2tp_ip_recvmsg,
|
||||
.backlog_rcv = l2tp_ip_backlog_recv,
|
||||
.hash = inet_hash,
|
||||
.unhash = inet_unhash,
|
||||
.obj_size = sizeof(struct l2tp_ip_sock),
|
||||
#ifdef CONFIG_COMPAT
|
||||
.compat_setsockopt = compat_ip_setsockopt,
|
||||
.compat_getsockopt = compat_ip_getsockopt,
|
||||
#endif
|
||||
};
|
||||
|
||||
static const struct proto_ops l2tp_ip_ops = {
|
||||
.family = PF_INET,
|
||||
.owner = THIS_MODULE,
|
||||
.release = inet_release,
|
||||
.bind = inet_bind,
|
||||
.connect = inet_dgram_connect,
|
||||
.socketpair = sock_no_socketpair,
|
||||
.accept = sock_no_accept,
|
||||
.getname = l2tp_ip_getname,
|
||||
.poll = datagram_poll,
|
||||
.ioctl = inet_ioctl,
|
||||
.listen = sock_no_listen,
|
||||
.shutdown = inet_shutdown,
|
||||
.setsockopt = sock_common_setsockopt,
|
||||
.getsockopt = sock_common_getsockopt,
|
||||
.sendmsg = inet_sendmsg,
|
||||
.recvmsg = sock_common_recvmsg,
|
||||
.mmap = sock_no_mmap,
|
||||
.sendpage = sock_no_sendpage,
|
||||
#ifdef CONFIG_COMPAT
|
||||
.compat_setsockopt = compat_sock_common_setsockopt,
|
||||
.compat_getsockopt = compat_sock_common_getsockopt,
|
||||
#endif
|
||||
};
|
||||
|
||||
static struct inet_protosw l2tp_ip_protosw = {
|
||||
.type = SOCK_DGRAM,
|
||||
.protocol = IPPROTO_L2TP,
|
||||
.prot = &l2tp_ip_prot,
|
||||
.ops = &l2tp_ip_ops,
|
||||
.no_check = 0,
|
||||
};
|
||||
|
||||
static struct net_protocol l2tp_ip_protocol __read_mostly = {
|
||||
.handler = l2tp_ip_recv,
|
||||
};
|
||||
|
||||
static int __init l2tp_ip_init(void)
|
||||
{
|
||||
int err;
|
||||
|
||||
printk(KERN_INFO "L2TP IP encapsulation support (L2TPv3)\n");
|
||||
|
||||
err = proto_register(&l2tp_ip_prot, 1);
|
||||
if (err != 0)
|
||||
goto out;
|
||||
|
||||
err = inet_add_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
|
||||
if (err)
|
||||
goto out1;
|
||||
|
||||
inet_register_protosw(&l2tp_ip_protosw);
|
||||
return 0;
|
||||
|
||||
out1:
|
||||
proto_unregister(&l2tp_ip_prot);
|
||||
out:
|
||||
return err;
|
||||
}
|
||||
|
||||
static void __exit l2tp_ip_exit(void)
|
||||
{
|
||||
inet_unregister_protosw(&l2tp_ip_protosw);
|
||||
inet_del_protocol(&l2tp_ip_protocol, IPPROTO_L2TP);
|
||||
proto_unregister(&l2tp_ip_prot);
|
||||
}
|
||||
|
||||
module_init(l2tp_ip_init);
|
||||
module_exit(l2tp_ip_exit);
|
||||
|
||||
MODULE_LICENSE("GPL");
|
||||
MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
|
||||
MODULE_DESCRIPTION("L2TP over IP");
|
||||
MODULE_VERSION("1.0");
|
||||
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, SOCK_DGRAM, IPPROTO_L2TP);
|
||||
|
|
@ -305,6 +305,7 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
|
|||
struct l2tp_session *session;
|
||||
struct l2tp_tunnel *tunnel;
|
||||
struct pppol2tp_session *ps;
|
||||
int uhlen;
|
||||
|
||||
error = -ENOTCONN;
|
||||
if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
|
||||
|
|
@ -321,10 +322,12 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
|
|||
if (tunnel == NULL)
|
||||
goto error_put_sess;
|
||||
|
||||
uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
|
||||
|
||||
/* Allocate a socket buffer */
|
||||
error = -ENOMEM;
|
||||
skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
|
||||
sizeof(struct udphdr) + session->hdr_len +
|
||||
uhlen + session->hdr_len +
|
||||
sizeof(ppph) + total_len,
|
||||
0, GFP_KERNEL);
|
||||
if (!skb)
|
||||
|
|
@ -335,7 +338,7 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
|
|||
skb_reset_network_header(skb);
|
||||
skb_reserve(skb, sizeof(struct iphdr));
|
||||
skb_reset_transport_header(skb);
|
||||
skb_reserve(skb, sizeof(struct udphdr));
|
||||
skb_reserve(skb, uhlen);
|
||||
|
||||
/* Add PPP header */
|
||||
skb->data[0] = ppph[0];
|
||||
|
|
|
|||
Reference in New Issue