tor-android/external/badvpn_dns/flow/PacketRouter.h

127 lines
5.3 KiB
C

/**
* @file PacketRouter.h
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @section DESCRIPTION
*
* Object which simplifies routing packets to {@link RouteBuffer}'s from a
* {@link PacketRecvInterface} input.
*/
#ifndef BADVPN_FLOW_PACKETROUTER_H
#define BADVPN_FLOW_PACKETROUTER_H
#include <base/DebugObject.h>
#include <base/BPending.h>
#include <flow/PacketRecvInterface.h>
#include <flow/RouteBuffer.h>
/**
* Handler called when a packet is received, allowing the user to route it
* to one or more buffers using {@link PacketRouter_Route}.
*
* @param user as in {@link PacketRouter_Init}
* @param buf the buffer for the packet. May be modified by the user.
* Will have space for mtu bytes. Only valid in the job context of
* this handler, until {@link PacketRouter_Route} is called successfully.
* @param recv_len length of the input packet (located at recv_offset bytes offset)
*/
typedef void (*PacketRouter_handler) (void *user, uint8_t *buf, int recv_len);
/**
* Object which simplifies routing packets to {@link RouteBuffer}'s from a
* {@link PacketRecvInterface} input.
*
* Packets are routed by calling {@link PacketRouter_Route} (possibly multiple times)
* from the job context of the {@link PacketRouter_handler} handler.
*/
typedef struct {
int mtu;
int recv_offset;
PacketRecvInterface *input;
PacketRouter_handler handler;
void *user;
RouteBufferSource rbs;
BPending next_job;
DebugObject d_obj;
} PacketRouter;
/**
* Initializes the object.
*
* @param o the object
* @param mtu maximum packet size. Must be >=0. It will only be possible to route packets to
* {@link RouteBuffer}'s with the same MTU.
* @param recv_offset offset from the beginning for receiving input packets.
* Must be >=0 and <=mtu. The leading space should be initialized
* by the user before routing a packet.
* @param input input interface. Its MTU must be <= mtu - recv_offset.
* @param handler handler called when a packet is received to allow the user to route it
* @param user value passed to handler
* @param pg pending group
* @return 1 on success, 0 on failure
*/
int PacketRouter_Init (PacketRouter *o, int mtu, int recv_offset, PacketRecvInterface *input, PacketRouter_handler handler, void *user, BPendingGroup *pg) WARN_UNUSED;
/**
* Frees the object.
*
* @param o the object
*/
void PacketRouter_Free (PacketRouter *o);
/**
* Routes the current packet to the given buffer.
* Must be called from the job context of the {@link PacketRouter_handler} handler.
* On success, copies part of the current packet to next one (regardless if next_buf
* is provided or not; if not, copies before receiving another packet).
*
* @param o the object
* @param len total packet length (e.g. recv_offset + (recv_len from handler)).
* Must be >=0 and <=mtu.
* @param output buffer to route to. Its MTU must be the same as of this object.
* @param next_buf if not NULL, on success, will be set to the address of a new current
* packet that can be routed. The pointer will be valid in the job context of
* the calling handler, until this function is called successfully again
* (as for the original pointer provided by the handler).
* @param copy_offset Offset from the beginning for copying to the next packet.
* Must be >=0 and <=mtu.
* @param copy_len Number of bytes to copy from the old current
* packet to the next one. Must be >=0 and <= mtu - copy_offset.
* @return 1 on success, 0 on failure (buffer full)
*/
int PacketRouter_Route (PacketRouter *o, int len, RouteBuffer *output, uint8_t **next_buf, int copy_offset, int copy_len);
/**
* Asserts that {@link PacketRouter_Route} can be called.
*
* @param o the object
*/
void PacketRouter_AssertRoute (PacketRouter *o);
#endif