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1 office 1 /**
2 * @file RouteBuffer.h
3 * @author Ambroz Bizjak <ambrop7@gmail.com>
4 *
5 * @section LICENSE
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the author nor the
15 * names of its contributors may be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
22 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
23 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
25 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
27 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * @section DESCRIPTION
30 *
31 * Packet buffer for zero-copy packet routing.
32 */
33  
34 #ifndef BADVPN_FLOW_ROUTEBUFFER_H
35 #define BADVPN_FLOW_ROUTEBUFFER_H
36  
37 #include <misc/debug.h>
38 #include <structure/LinkedList1.h>
39 #include <base/DebugObject.h>
40 #include <flow/PacketPassInterface.h>
41  
42 struct RouteBuffer_packet {
43 LinkedList1Node node;
44 int len;
45 };
46  
47 /**
48 * Packet buffer for zero-copy packet routing.
49 *
50 * Packets are buffered using {@link RouteBufferSource} objects.
51 */
52 typedef struct {
53 int mtu;
54 PacketPassInterface *output;
55 LinkedList1 packets_free;
56 LinkedList1 packets_used;
57 DebugObject d_obj;
58 } RouteBuffer;
59  
60 /**
61 * Object through which packets are buffered into {@link RouteBuffer} objects.
62 *
63 * A packet is routed by calling {@link RouteBufferSource_Pointer}, writing it to
64 * the returned address, then calling {@link RouteBufferSource_Route}.
65 */
66 typedef struct {
67 int mtu;
68 struct RouteBuffer_packet *current_packet;
69 DebugObject d_obj;
70 } RouteBufferSource;
71  
72 /**
73 * Initializes the object.
74 *
75 * @param o the object
76 * @param mtu maximum packet size. Must be >=0. It will only be possible to route packets to this buffer
77 * from {@link RouteBufferSource}.s with the same MTU.
78 * @param output output interface. Its MTU must be >=mtu.
79 * @param buf_size size of the buffer in number of packet. Must be >0.
80 * @return 1 on success, 0 on failure
81 */
82 int RouteBuffer_Init (RouteBuffer *o, int mtu, PacketPassInterface *output, int buf_size) WARN_UNUSED;
83  
84 /**
85 * Frees the object.
86 */
87 void RouteBuffer_Free (RouteBuffer *o);
88  
89 /**
90 * Retuns the buffer's MTU (mtu argument to {@link RouteBuffer_Init}).
91 *
92 * @return MTU
93 */
94 int RouteBuffer_GetMTU (RouteBuffer *o);
95  
96 /**
97 * Initializes the object.
98 *
99 * @param o the object
100 * @param mtu maximum packet size. Must be >=0. The object will only be able to route packets
101 * to {@link RouteBuffer}'s with the same MTU.
102 * @return 1 on success, 0 on failure
103 */
104 int RouteBufferSource_Init (RouteBufferSource *o, int mtu) WARN_UNUSED;
105  
106 /**
107 * Frees the object.
108 *
109 * @param o the object
110 */
111 void RouteBufferSource_Free (RouteBufferSource *o);
112  
113 /**
114 * Returns a pointer to the current packet.
115 * The pointed to memory area will have space for MTU bytes.
116 * The pointer is only valid until {@link RouteBufferSource_Route} succeeds.
117 *
118 * @param o the object
119 * @return pointer to the current packet
120 */
121 uint8_t * RouteBufferSource_Pointer (RouteBufferSource *o);
122  
123 /**
124 * Routes the current packet to a given buffer.
125 * On success, this invalidates the pointer previously returned from
126 * {@link RouteBufferSource_Pointer}.
127 *
128 * @param o the object
129 * @param len length of the packet. Must be >=0 and <=MTU.
130 * @param b buffer to route to. Its MTU must equal this object's MTU.
131 * @param copy_offset Offset from the beginning for copying. Must be >=0 and
132 * <=mtu.
133 * @param copy_len Number of bytes to copy from the old current packet to the new one.
134 * Must be >=0 and <= mtu - copy_offset.
135 * @return 1 on success, 0 on failure
136 */
137 int RouteBufferSource_Route (RouteBufferSource *o, int len, RouteBuffer *b, int copy_offset, int copy_len);
138  
139 #endif