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author | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2020-04-30 19:03:56 +0300 |
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committer | David S. Miller <davem@davemloft.net> | 2020-04-30 22:56:35 +0300 |
commit | 10ebb22137acd97083cb52d8664cdff269e8a629 (patch) | |
tree | cda38bdfc48f30e9583e1ce79c64f4adadd31ae7 | |
parent | 9f04960660bf5468caaf9da2752f6f35020e4679 (diff) | |
download | linux-10ebb22137acd97083cb52d8664cdff269e8a629.tar.xz |
docs: networking: convert l2tp.txt to ReST
- add SPDX header;
- add a document title;
- mark tables as such;
- adjust identation, whitespaces and blank lines;
- add to networking/index.rst.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r-- | Documentation/networking/index.rst | 1 | ||||
-rw-r--r-- | Documentation/networking/l2tp.rst (renamed from Documentation/networking/l2tp.txt) | 159 |
2 files changed, 87 insertions, 73 deletions
diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst index e1ff08b94d90..0c5d7a037983 100644 --- a/Documentation/networking/index.rst +++ b/Documentation/networking/index.rst @@ -74,6 +74,7 @@ Contents: ipvlan ipvs-sysctl kcm + l2tp .. only:: subproject and html diff --git a/Documentation/networking/l2tp.txt b/Documentation/networking/l2tp.rst index 9bc271cdc9a8..a48238a2ec09 100644 --- a/Documentation/networking/l2tp.txt +++ b/Documentation/networking/l2tp.rst @@ -1,3 +1,9 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==== +L2TP +==== + This document describes how to use the kernel's L2TP drivers to provide L2TP functionality. L2TP is a protocol that tunnels one or more sessions over an IP tunnel. It is commonly used for VPNs @@ -121,14 +127,16 @@ Userspace may control behavior of the tunnel or session using setsockopt and ioctl on the PPPoX socket. The following socket options are supported:- -DEBUG - bitmask of debug message categories. See below. -SENDSEQ - 0 => don't send packets with sequence numbers - 1 => send packets with sequence numbers -RECVSEQ - 0 => receive packet sequence numbers are optional - 1 => drop receive packets without sequence numbers -LNSMODE - 0 => act as LAC. - 1 => act as LNS. -REORDERTO - reorder timeout (in millisecs). If 0, don't try to reorder. +========= =========================================================== +DEBUG bitmask of debug message categories. See below. +SENDSEQ - 0 => don't send packets with sequence numbers + - 1 => send packets with sequence numbers +RECVSEQ - 0 => receive packet sequence numbers are optional + - 1 => drop receive packets without sequence numbers +LNSMODE - 0 => act as LAC. + - 1 => act as LNS. +REORDERTO reorder timeout (in millisecs). If 0, don't try to reorder. +========= =========================================================== Only the DEBUG option is supported by the special tunnel management PPPoX socket. @@ -177,20 +185,22 @@ setsockopt on the PPPoX socket to set a debug mask. The following debug mask bits are available: +================ ============================== L2TP_MSG_DEBUG verbose debug (if compiled in) L2TP_MSG_CONTROL userspace - kernel interface L2TP_MSG_SEQ sequence numbers handling L2TP_MSG_DATA data packets +================ ============================== If enabled, files under a l2tp debugfs directory can be used to dump kernel state about L2TP tunnels and sessions. To access it, the -debugfs filesystem must first be mounted. +debugfs filesystem must first be mounted:: -# mount -t debugfs debugfs /debug + # mount -t debugfs debugfs /debug -Files under the l2tp directory can then be accessed. +Files under the l2tp directory can then be accessed:: -# cat /debug/l2tp/tunnels + # cat /debug/l2tp/tunnels The debugfs files should not be used by applications to obtain L2TP state information because the file format is subject to change. It is @@ -211,14 +221,14 @@ iproute2's ip utility to support this. To create an L2TPv3 ethernet pseudowire between local host 192.168.1.1 and peer 192.168.1.2, using IP addresses 10.5.1.1 and 10.5.1.2 for the -tunnel endpoints:- +tunnel endpoints:: -# ip l2tp add tunnel tunnel_id 1 peer_tunnel_id 1 udp_sport 5000 \ - udp_dport 5000 encap udp local 192.168.1.1 remote 192.168.1.2 -# ip l2tp add session tunnel_id 1 session_id 1 peer_session_id 1 -# ip -s -d show dev l2tpeth0 -# ip addr add 10.5.1.2/32 peer 10.5.1.1/32 dev l2tpeth0 -# ip li set dev l2tpeth0 up + # ip l2tp add tunnel tunnel_id 1 peer_tunnel_id 1 udp_sport 5000 \ + udp_dport 5000 encap udp local 192.168.1.1 remote 192.168.1.2 + # ip l2tp add session tunnel_id 1 session_id 1 peer_session_id 1 + # ip -s -d show dev l2tpeth0 + # ip addr add 10.5.1.2/32 peer 10.5.1.1/32 dev l2tpeth0 + # ip li set dev l2tpeth0 up Choose IP addresses to be the address of a local IP interface and that of the remote system. The IP addresses of the l2tpeth0 interface can be @@ -228,75 +238,78 @@ Repeat the above at the peer, with ports, tunnel/session ids and IP addresses reversed. The tunnel and session IDs can be any non-zero 32-bit number, but the values must be reversed at the peer. +======================== =================== Host 1 Host2 +======================== =================== udp_sport=5000 udp_sport=5001 udp_dport=5001 udp_dport=5000 tunnel_id=42 tunnel_id=45 peer_tunnel_id=45 peer_tunnel_id=42 session_id=128 session_id=5196755 peer_session_id=5196755 peer_session_id=128 +======================== =================== When done at both ends of the tunnel, it should be possible to send -data over the network. e.g. +data over the network. e.g.:: -# ping 10.5.1.1 + # ping 10.5.1.1 Sample Userspace Code ===================== -1. Create tunnel management PPPoX socket - - kernel_fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP); - if (kernel_fd >= 0) { - struct sockaddr_pppol2tp sax; - struct sockaddr_in const *peer_addr; - - peer_addr = l2tp_tunnel_get_peer_addr(tunnel); - memset(&sax, 0, sizeof(sax)); - sax.sa_family = AF_PPPOX; - sax.sa_protocol = PX_PROTO_OL2TP; - sax.pppol2tp.fd = udp_fd; /* fd of tunnel UDP socket */ - sax.pppol2tp.addr.sin_addr.s_addr = peer_addr->sin_addr.s_addr; - sax.pppol2tp.addr.sin_port = peer_addr->sin_port; - sax.pppol2tp.addr.sin_family = AF_INET; - sax.pppol2tp.s_tunnel = tunnel_id; - sax.pppol2tp.s_session = 0; /* special case: mgmt socket */ - sax.pppol2tp.d_tunnel = 0; - sax.pppol2tp.d_session = 0; /* special case: mgmt socket */ - - if(connect(kernel_fd, (struct sockaddr *)&sax, sizeof(sax) ) < 0 ) { - perror("connect failed"); - result = -errno; - goto err; - } - } - -2. Create session PPPoX data socket - - struct sockaddr_pppol2tp sax; - int fd; - - /* Note, the target socket must be bound already, else it will not be ready */ - sax.sa_family = AF_PPPOX; - sax.sa_protocol = PX_PROTO_OL2TP; - sax.pppol2tp.fd = tunnel_fd; - sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr; - sax.pppol2tp.addr.sin_port = addr->sin_port; - sax.pppol2tp.addr.sin_family = AF_INET; - sax.pppol2tp.s_tunnel = tunnel_id; - sax.pppol2tp.s_session = session_id; - sax.pppol2tp.d_tunnel = peer_tunnel_id; - sax.pppol2tp.d_session = peer_session_id; - - /* session_fd is the fd of the session's PPPoL2TP socket. - * tunnel_fd is the fd of the tunnel UDP socket. - */ - fd = connect(session_fd, (struct sockaddr *)&sax, sizeof(sax)); - if (fd < 0 ) { - return -errno; - } - return 0; +1. Create tunnel management PPPoX socket:: + + kernel_fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP); + if (kernel_fd >= 0) { + struct sockaddr_pppol2tp sax; + struct sockaddr_in const *peer_addr; + + peer_addr = l2tp_tunnel_get_peer_addr(tunnel); + memset(&sax, 0, sizeof(sax)); + sax.sa_family = AF_PPPOX; + sax.sa_protocol = PX_PROTO_OL2TP; + sax.pppol2tp.fd = udp_fd; /* fd of tunnel UDP socket */ + sax.pppol2tp.addr.sin_addr.s_addr = peer_addr->sin_addr.s_addr; + sax.pppol2tp.addr.sin_port = peer_addr->sin_port; + sax.pppol2tp.addr.sin_family = AF_INET; + sax.pppol2tp.s_tunnel = tunnel_id; + sax.pppol2tp.s_session = 0; /* special case: mgmt socket */ + sax.pppol2tp.d_tunnel = 0; + sax.pppol2tp.d_session = 0; /* special case: mgmt socket */ + + if(connect(kernel_fd, (struct sockaddr *)&sax, sizeof(sax) ) < 0 ) { + perror("connect failed"); + result = -errno; + goto err; + } + } + +2. Create session PPPoX data socket:: + + struct sockaddr_pppol2tp sax; + int fd; + + /* Note, the target socket must be bound already, else it will not be ready */ + sax.sa_family = AF_PPPOX; + sax.sa_protocol = PX_PROTO_OL2TP; + sax.pppol2tp.fd = tunnel_fd; + sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr; + sax.pppol2tp.addr.sin_port = addr->sin_port; + sax.pppol2tp.addr.sin_family = AF_INET; + sax.pppol2tp.s_tunnel = tunnel_id; + sax.pppol2tp.s_session = session_id; + sax.pppol2tp.d_tunnel = peer_tunnel_id; + sax.pppol2tp.d_session = peer_session_id; + + /* session_fd is the fd of the session's PPPoL2TP socket. + * tunnel_fd is the fd of the tunnel UDP socket. + */ + fd = connect(session_fd, (struct sockaddr *)&sax, sizeof(sax)); + if (fd < 0 ) { + return -errno; + } + return 0; Internal Implementation ======================= |