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1 /** @file
2   Tcp option's routine header file.
3 
4 Copyright (c) 2005 - 2009, Intel Corporation. All rights reserved.<BR>
5 This program and the accompanying materials
6 are licensed and made available under the terms and conditions of the BSD License
7 which accompanies this distribution.  The full text of the license may be found at
8 http://opensource.org/licenses/bsd-license.php<BR>
9 
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
12 
13 **/
14 
15 #ifndef _TCP4_OPTION_H_
16 #define _TCP4_OPTION_H_
17 
18 ///
19 /// The structure to store the parse option value.
20 /// ParseOption only parse the options, don't process them.
21 ///
22 typedef struct _TCP_OPTION {
23   UINT8   Flag;     ///< Flag such as TCP_OPTION_RCVD_MSS
24   UINT8   WndScale; ///< The WndScale received
25   UINT16  Mss;      ///< The Mss received
26   UINT32  TSVal;    ///< The TSVal field in a timestamp option
27   UINT32  TSEcr;    ///< The TSEcr field in a timestamp option
28 } TCP_OPTION;
29 
30 //
31 // supported TCP option type and their length
32 //
33 #define TCP_OPTION_EOP             0  ///< End Of oPtion
34 #define TCP_OPTION_NOP             1  ///< No-Option.
35 #define TCP_OPTION_MSS             2  ///< Maximum Segment Size
36 #define TCP_OPTION_WS              3  ///< Window scale
37 #define TCP_OPTION_TS              8  ///< Timestamp
38 #define TCP_OPTION_MSS_LEN         4  ///< Length of MSS option
39 #define TCP_OPTION_WS_LEN          3  ///< Length of window scale option
40 #define TCP_OPTION_TS_LEN          10 ///< Length of timestamp option
41 #define TCP_OPTION_WS_ALIGNED_LEN  4  ///< Length of window scale option, aligned
42 #define TCP_OPTION_TS_ALIGNED_LEN  12 ///< Length of timestamp option, aligned
43 
44 //
45 // recommend format of timestamp window scale
46 // option for fast process.
47 //
48 #define TCP_OPTION_TS_FAST ((TCP_OPTION_NOP << 24) | \
49                             (TCP_OPTION_NOP << 16) | \
50                             (TCP_OPTION_TS << 8)   | \
51                             (TCP_OPTION_TS_LEN))
52 
53 #define TCP_OPTION_WS_FAST   ((TCP_OPTION_NOP << 24) | \
54                               (TCP_OPTION_WS << 16)  | \
55                               (TCP_OPTION_WS_LEN << 8))
56 
57 #define TCP_OPTION_MSS_FAST  ((TCP_OPTION_MSS << 24) | (TCP_OPTION_MSS_LEN << 16))
58 
59 //
60 // Other misc definations
61 //
62 #define TCP_OPTION_RCVD_MSS        0x01
63 #define TCP_OPTION_RCVD_WS         0x02
64 #define TCP_OPTION_RCVD_TS         0x04
65 #define TCP_OPTION_MAX_WS          14      ///< Maxium window scale value
66 #define TCP_OPTION_MAX_WIN         0xffff  ///< Max window size in TCP header
67 
68 
69 /**
70   Compute the window scale value according to the given buffer size.
71 
72   @param  Tcb     Pointer to the TCP_CB of this TCP instance.
73 
74   @return  The scale value.
75 
76 **/
77 UINT8
78 TcpComputeScale (
79   IN TCP_CB *Tcb
80   );
81 
82 /**
83   Build the TCP option in three-way handshake.
84 
85   @param  Tcb     Pointer to the TCP_CB of this TCP instance.
86   @param  Nbuf    Pointer to the buffer to store the options.
87 
88   @return  The total length of the TCP option field.
89 
90 **/
91 UINT16
92 TcpSynBuildOption (
93   IN TCP_CB  *Tcb,
94   IN NET_BUF *Nbuf
95   );
96 
97 /**
98   Build the TCP option in synchronized states.
99 
100   @param  Tcb     Pointer to the TCP_CB of this TCP instance.
101   @param  Nbuf    Pointer to the buffer to store the options.
102 
103   @return  The total length of the TCP option field.
104 
105 **/
106 UINT16
107 TcpBuildOption (
108   IN TCP_CB  *Tcb,
109   IN NET_BUF *Nbuf
110   );
111 
112 /**
113   Parse the supported options.
114 
115   @param  Tcp     Pointer to the TCP_CB of this TCP instance.
116   @param  Option  Pointer to the TCP_OPTION used to store the successfully pasrsed
117                   options.
118 
119   @retval 0       The options are successfully pasrsed.
120   @retval -1      Ilegal option was found.
121 
122 **/
123 INTN
124 TcpParseOption (
125   IN     TCP_HEAD   *Tcp,
126   IN OUT TCP_OPTION *Option
127   );
128 
129 /**
130   Check the segment against PAWS.
131 
132   @param  Tcb     Pointer to the TCP_CB of this TCP instance.
133   @param  TSVal   The timestamp value.
134 
135   @retval 1       The segment passed the PAWS check.
136   @retval 0       The segment failed to pass the PAWS check.
137 
138 **/
139 UINT32
140 TcpPawsOK (
141   IN TCP_CB *Tcb,
142   IN UINT32 TSVal
143   );
144 
145 #endif
146