/* * OpenVPN -- An application to securely tunnel IP networks * over a single TCP/UDP port, with support for SSL/TLS-based * session authentication and key exchange, * packet encryption, packet authentication, and * packet compression. * * Copyright (C) 2002-2010 OpenVPN Technologies, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program (see the file COPYING included with this * distribution); if not, write to the Free Software Foundation, Inc., * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /** * @file * Interface functions to the internal and external multiplexers. */ #ifndef FORWARD_H #define FORWARD_H #include "openvpn.h" #include "occ.h" #include "ping.h" #define TUN_OUT(c) (BLEN(&(c)->c2.to_tun) > 0) #define LINK_OUT(c) (BLEN(&(c)->c2.to_link) > 0) #define ANY_OUT(c) (TUN_OUT(c) || LINK_OUT(c)) #ifdef ENABLE_FRAGMENT #define TO_LINK_FRAG(c) ((c)->c2.fragment && fragment_outgoing_defined ((c)->c2.fragment)) #else #define TO_LINK_FRAG(c) (false) #endif #define TO_LINK_DEF(c) (LINK_OUT(c) || TO_LINK_FRAG(c)) #define IOW_TO_TUN (1<<0) #define IOW_TO_LINK (1<<1) #define IOW_READ_TUN (1<<2) #define IOW_READ_LINK (1<<3) #define IOW_SHAPER (1<<4) #define IOW_CHECK_RESIDUAL (1<<5) #define IOW_FRAG (1<<6) #define IOW_MBUF (1<<7) #define IOW_READ_TUN_FORCE (1<<8) #define IOW_WAIT_SIGNAL (1<<9) #define IOW_READ (IOW_READ_TUN|IOW_READ_LINK) void pre_select (struct context *c); void process_io (struct context *c); const char *wait_status_string (struct context *c, struct gc_arena *gc); void show_wait_status (struct context *c); /**********************************************************************/ /** * Process a data channel packet that will be sent through a VPN tunnel. * @ingroup data_control * * This function controls the processing of a data channel packet which * will be sent through a VPN tunnel to a remote OpenVPN peer. It's * general structure is as follows: * - Check that the client authentication has succeeded; if not, drop the * packet. * - If the \a comp_frag argument is true: * - Call \c lzo_compress() of the \link Data Channel Compression * module\endlink to (possibly) compress the packet. * - Call \c fragment_outgoing() of the \link Data Channel Fragmentation * module\endlink to (possibly) fragment the packet. * - Activate the \link Data Channel Crypto module\endlink to perform * security operations on the packet. * - Call \c tls_pre_encrypt() to choose the appropriate security * parameters for this packet. * - Call \c openvpn_encrypt() to encrypt and HMAC signed the packet. * - Call \c tls_post_encrypt() to prepend the one-byte OpenVPN header * and do some TLS accounting. * - Place the resulting packet in \c c->c2.to_link so that it can be sent * over the external network interface to its remote destination by the * \link external_multiplexer External Multiplexer\endlink. * * @param c - The context structure of the VPN tunnel associated with this * packet. * @param comp_frag - Whether to do packet compression and fragmentation. * This flag is set to true the first time a packet is processed. If * the packet then gets fragmented, this function will be called again * once for each remaining fragment with this parameter set to false. */ void encrypt_sign (struct context *c, bool comp_frag); /**********************************************************************/ /** * Read a packet from the external network interface. * @ingroup external_multiplexer * * The packet read from the external network interface is stored in \c * c->c2.buf and its source address in \c c->c2.from. If an error * occurred, the length of \c c->c2.buf will be 0. * * OpenVPN running as client or as UDP server only has a single external * network socket, so this function can be called with the single (client * mode) or top level (UDP server) context as its argument. OpenVPN * running as TCP server, on the other hand, has a network socket for each * active VPN tunnel. In that case this function must be called with the * context associated with the appropriate VPN tunnel for which data is * available to be read. * * @param c - The context structure which contains the external * network socket from which to read incoming packets. */ void read_incoming_link (struct context *c); /** * Starts processing a packet read from the external network interface. * @ingroup external_multiplexer * * This function starts the processing of a data channel packet which * has come out of a VPN tunnel. It's high-level structure is as follows: * - Verify that a nonzero length packet has been received from a valid * source address for the given context \a c. * - Call \c tls_pre_decrypt(), which splits data channel and control * channel packets: * - If a data channel packet, the appropriate security parameters are * loaded. * - If a control channel packet, this function process is it and * afterwards sets the packet's buffer length to 0, so that the data * channel processing steps below will ignore it. * - Call \c openvpn_decrypt() of the \link data_crypto Data Channel * Crypto module\endlink to authenticate and decrypt the packet using * the security parameters loaded by \c tls_pre_decrypt() above. * * @param c - The context structure of the VPN tunnel associated with the * packet. * @param lsi - link_socket_info obtained from context before processing. * @param floated - Flag indicates that peer has floated. * * @return true if packet is authenticated, false otherwise. */ bool process_incoming_link_part1 (struct context *c, struct link_socket_info *lsi, bool floated); /** * Continues processing a packet read from the external network interface. * @ingroup external_multiplexer * * This function continues the processing of a data channel packet which * has come out of a VPN tunnel. It must be called after * \c process_incoming_link_part1() function. * * It's high-level structure is as follows: * - Call \c fragment_incoming() of the \link fragmentation Data Channel * Fragmentation module\endlink to reassemble the packet if it's * fragmented. * - Call \c lzo_decompress() of the \link compression Data Channel * Compression module\endlink to decompress the packet if it's * compressed. * - Place the resulting packet in \c c->c2.to_tun so that it can be sent * over the virtual tun/tap network interface to its local destination * by the \link internal_multiplexer Internal Multiplexer\endlink. * * @param c - The context structure of the VPN tunnel associated with the * packet. * @param lsi - link_socket_info obtained from context before processing. * @param orig_buf - Pointer to a buffer data. * */ void process_incoming_link_part2 (struct context *c, struct link_socket_info *lsi, const uint8_t *orig_buf); /** * Write a packet to the external network interface. * @ingroup external_multiplexer * * This function writes the packet stored in \c c->c2.to_link to the * external network device contained within \c c->c1.link_socket. * * If an error occurs, it is logged and the packet is dropped. * * @param c - The context structure of the VPN tunnel associated with the * packet. */ void process_outgoing_link (struct context *c); /**************************************************************************/ /** * Read a packet from the virtual tun/tap network interface. * @ingroup internal_multiplexer * * This function reads a packet from the virtual tun/tap network device \c * c->c1.tuntap and stores it in \c c->c2.buf. * * If an error occurs, it is logged and the packet is dropped. * * @param c - The context structure in which to store the received * packet. */ void read_incoming_tun (struct context *c); /** * Process a packet read from the virtual tun/tap network interface. * @ingroup internal_multiplexer * * This function calls \c encrypt_sign() of the \link data_control Data * Channel Control module\endlink to process the packet. * * If an error occurs, it is logged and the packet is dropped. * * @param c - The context structure of the VPN tunnel associated with the * packet. */ void process_incoming_tun (struct context *c); /** * Write a packet to the virtual tun/tap network interface. * @ingroup internal_multiplexer * * This function writes the packet stored in \c c->c2.to_tun to the * virtual tun/tap network device \c c->c1.tuntap. * * If an error occurs, it is logged and the packet is dropped. * * @param c - The context structure of the VPN tunnel associated with * the packet. */ void process_outgoing_tun (struct context *c); /**************************************************************************/ bool send_control_channel_string (struct context *c, const char *str, int msglevel); #define PIPV4_PASSTOS (1<<0) #define PIP_MSSFIX (1<<1) /* v4 and v6 */ #define PIPV4_OUTGOING (1<<2) #define PIPV4_EXTRACT_DHCP_ROUTER (1<<3) #define PIPV4_CLIENT_NAT (1<<4) void process_ip_header (struct context *c, unsigned int flags, struct buffer *buf); #if P2MP void schedule_exit (struct context *c, const int n_seconds, const int signal); #endif #endif /* FORWARD_H */