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30 | * @{ |
30 | * @{ |
31 | */ |
31 | */ |
32 | 32 | ||
33 | /** @file |
33 | /** @file |
34 | * TCP header definition. |
34 | * TCP header definition. |
35 | * Names according to the linux src/include/linux/tcp.h header file. |
35 | * Based on the RFC~793. |
36 | */ |
36 | */ |
37 | 37 | ||
38 | #ifndef __NET_TCP_HEADER_H__ |
38 | #ifndef __NET_TCP_HEADER_H__ |
39 | #define __NET_TCP_HEADER_H__ |
39 | #define __NET_TCP_HEADER_H__ |
40 | 40 | ||
41 | #include <sys/types.h> |
41 | #include <sys/types.h> |
42 | 42 | ||
- | 43 | /** Returns the actual TCP header length. |
|
- | 44 | * @param header The TCP packet header. Input parameter. |
|
- | 45 | */ |
|
- | 46 | #define TCP_HEADER_LENGTH( header ) (( header )->header_length * 4u ) |
|
- | 47 | ||
- | 48 | /** Returns the actual TCP header length. |
|
- | 49 | * @param header The TCP packet header. Input parameter. |
|
- | 50 | */ |
|
- | 51 | #define TCP_COMPUTE_HEADER_LENGTH( length ) (( uint8_t ) (( length ) / 4u )) |
|
- | 52 | ||
43 | /** Type definition of the transmission datagram header. |
53 | /** Type definition of the transmission datagram header. |
44 | * @see tcp_header |
54 | * @see tcp_header |
45 | */ |
55 | */ |
46 | typedef struct tcp_header tcp_header_t; |
56 | typedef struct tcp_header tcp_header_t; |
47 | 57 | ||
48 | /** Type definition of the transmission datagram header pointer. |
58 | /** Type definition of the transmission datagram header pointer. |
49 | * @see tcp_header |
59 | * @see tcp_header |
50 | */ |
60 | */ |
51 | typedef tcp_header_t * tcp_header_ref; |
61 | typedef tcp_header_t * tcp_header_ref; |
52 | 62 | ||
- | 63 | /** Type definition of the transmission datagram header option. |
|
- | 64 | * @see tcp_option |
|
- | 65 | */ |
|
- | 66 | typedef struct tcp_option tcp_option_t; |
|
- | 67 | ||
- | 68 | /** Type definition of the transmission datagram header option pointer. |
|
- | 69 | * @see tcp_option |
|
- | 70 | */ |
|
- | 71 | typedef tcp_option_t * tcp_option_ref; |
|
- | 72 | ||
- | 73 | /** Type definition of the Maximum segment size TCP option. |
|
- | 74 | * @see ... |
|
- | 75 | */ |
|
- | 76 | typedef struct tcp_max_segment_size_option tcp_max_segment_size_option_t; |
|
- | 77 | ||
- | 78 | /** Type definition of the Maximum segment size TCP option pointer. |
|
- | 79 | * @see tcp_max_segment_size_option |
|
- | 80 | */ |
|
- | 81 | typedef tcp_max_segment_size_option_t * tcp_max_segment_size_option_ref; |
|
- | 82 | ||
53 | /** Transmission datagram header. |
83 | /** Transmission datagram header. |
54 | */ |
84 | */ |
55 | struct tcp_header{ |
85 | struct tcp_header{ |
56 | /** The 16-bit source port number, used by the receiver to reply. |
86 | /** The source port number. |
57 | */ |
87 | */ |
58 | uint16_t source; |
88 | uint16_t source_port; |
59 | /** The 16-bit destination port number. |
89 | /** The destination port number. |
60 | */ |
90 | */ |
61 | uint16_t dest; |
91 | uint16_t destination_port; |
62 | /** The sequence number of the first data byte in this segment. |
92 | /** The sequence number of the first data octet in this segment (except when SYN is present). |
63 | * If the SYN control bit is set, the sequence number is the initial sequence number (n) and the first data byte is n+1. |
93 | * If SYN is present the sequence number is the initial sequence number (ISN) and the first data octet is ISN+1. |
64 | */ |
94 | */ |
65 | uint32_t seq; |
95 | uint32_t sequence_number; |
66 | /** If the ACK control bit is set, this field contains the value of the next sequence number that the receiver is expecting to receive. |
96 | /** If the ACK control bit is set this field contains the value of the next sequence number the sender of the segment is expecting to receive. |
- | 97 | * Once a~connection is established this is always sent. |
|
- | 98 | * @see acknowledge |
|
67 | */ |
99 | */ |
68 | uint32_t ack_seq; |
100 | uint32_t acknowledgement_number; |
69 | #ifdef ARCH_IS_BIG_ENDIAN |
101 | #ifdef ARCH_IS_BIG_ENDIAN |
70 | /** The number of 32-bit words in the TCP header. |
102 | /** The number of 32~bit words in the TCP Header. |
71 | * It indicates where the data begins. |
103 | * This indicates where the data begins. |
- | 104 | * The TCP header (even one including options) is an integral number of 32~bits long. |
|
72 | */ |
105 | */ |
73 | uint8_t doff:4; |
106 | uint8_t header_length:4; |
74 | /** Four bits reserved for future use. |
107 | /** Four bits reserved for future use. |
75 | * Must be zero. |
108 | * Must be zero. |
76 | */ |
109 | */ |
77 | uint8_t res1:4; |
110 | uint8_t reserved1:4; |
78 | #else |
111 | #else |
79 | /** Four bits reserved for future use. |
112 | /** Four bits reserved for future use. |
80 | * Must be zero. |
113 | * Must be zero. |
81 | */ |
114 | */ |
82 | uint8_t res1:4; |
115 | uint8_t reserved1:4; |
83 | /** The number of 32-bit words in the TCP header. |
116 | /** The number of 32~bit words in the TCP Header. |
84 | * It indicates where the data begins. |
117 | * This indicates where the data begins. |
- | 118 | * The TCP header (even one including options) is an integral number of 32~bits long. |
|
85 | */ |
119 | */ |
86 | uint8_t doff:4; |
120 | uint8_t header_length:4; |
87 | #endif |
121 | #endif |
88 | #ifdef ARCH_IS_BIG_ENDIAN |
122 | #ifdef ARCH_IS_BIG_ENDIAN |
89 | /** Two bits reserved for future use. |
123 | /** Two bits reserved for future use. |
90 | * Must be zero. |
124 | * Must be zero. |
91 | */ |
125 | */ |
92 | uint8_t res2:2; |
126 | uint8_t reserved2:2; |
93 | /** Indicates that the urgent pointer field is significant in this segment. |
127 | /** Urgent Pointer field significant. |
- | 128 | * @see tcp_header:urgent_pointer |
|
- | 129 | */ |
|
- | 130 | uint8_t urgent:1; |
|
- | 131 | /** Acknowledgment field significant |
|
- | 132 | * @see tcp_header:acknowledgement_number |
|
94 | */ |
133 | */ |
95 | uint8_t urg:1; |
- | |
96 | /** Indicates that the acknowledgment field is significant in this segment. |
- | |
97 | */ |
- | |
98 | uint8_t ack:1; |
134 | uint8_t acknowledge:1; |
99 | /** Push function. |
135 | /** Push function. |
100 | */ |
136 | */ |
101 | uint8_t psh:1; |
137 | uint8_t push:1; |
102 | /** Resets the connection. |
138 | /** Reset the connection. |
103 | */ |
139 | */ |
104 | uint8_t rst:1; |
140 | uint8_t reset:1; |
105 | /** Synchronizes the sequence numbers. |
141 | /** Synchronize the sequence numbers. |
106 | */ |
142 | */ |
107 | uint8_t syn:1; |
143 | uint8_t synchronize:1; |
108 | /** No more data from sender. |
144 | /** No more data from the sender. |
109 | */ |
145 | */ |
110 | uint8_t fin:1; |
146 | uint8_t finalize:1; |
111 | #else |
147 | #else |
112 | /** No more data from sender. |
148 | /** No more data from the sender. |
113 | */ |
149 | */ |
114 | uint8_t fin:1; |
150 | uint8_t finalize:1; |
115 | /** Synchronizes the sequence numbers. |
151 | /** Synchronize the sequence numbers. |
116 | */ |
152 | */ |
117 | uint8_t syn:1; |
153 | uint8_t synchronize:1; |
118 | /** Resets the connection. |
154 | /** Reset the connection. |
119 | */ |
155 | */ |
120 | uint8_t rst:1; |
156 | uint8_t reset:1; |
121 | /** Push function. |
157 | /** Push function. |
122 | */ |
158 | */ |
123 | uint8_t psh:1; |
159 | uint8_t push:1; |
124 | /** Indicates that the acknowledgment field is significant in this segment. |
160 | /** Acknowledgment field significant. |
- | 161 | * @see tcp_header:acknowledgement_number |
|
125 | */ |
162 | */ |
126 | uint8_t ack:1; |
163 | uint8_t acknowledge:1; |
127 | /** Indicates that the urgent pointer field is significant in this segment. |
164 | /** Urgent Pointer field significant. |
- | 165 | * @see tcp_header:urgent_pointer |
|
128 | */ |
166 | */ |
129 | uint8_t urg:1; |
167 | uint8_t urgent:1; |
130 | /** Two bits reserved for future use. |
168 | /** Two bits reserved for future use. |
131 | * Must be zero. |
169 | * Must be zero. |
132 | */ |
170 | */ |
133 | uint8_t res2:2; |
171 | uint8_t reserved2:2; |
134 | #endif |
172 | #endif |
135 | /** Used in ACK segments. |
- | |
136 | * It specifies the number of data bytes, beginning with the one indicated in the acknowledgment number field that the receiver (the sender of this segment) is willing to accept. |
173 | /** The number of data octets beginning with the one indicated in the acknowledgment field which the sender of this segment is willing to accept. |
- | 174 | * @see tcp_header:acknowledge |
|
137 | */ |
175 | */ |
138 | uint16_t window; |
176 | uint16_t window; |
139 | /** The 16-bit one's complement of the one's complement sum of all 16-bit words in a pseudo-header, the TCP header, and the TCP data. |
177 | /** The checksum field is the 16~bit one's complement of the one's complement sum of all 16~bit words in the header and text. |
- | 178 | * If a~segment contains an odd number of header and text octets to be checksummed, the last octet is padded on the right with zeros to form a~16~bit word for checksum purposes. |
|
- | 179 | * The pad is not transmitted as part of the segment. |
|
140 | * While computing the checksum, the checksum field itself is considered zero. |
180 | * While computing the checksum, the checksum field itself is replaced with zeros. |
- | 181 | * The checksum also coves a~pseudo header conceptually. |
|
141 | * The pseudo header conceptually prefixed to the TCP header contains the source address, the destination address, the protocol, and the TCP length. |
182 | * The pseudo header conceptually prefixed to the TCP header contains the source address, the destination address, the protocol, and the TCP length. |
142 | * This information gives protection against misrouted datagrams. |
183 | * This information gives protection against misrouted datagrams. |
143 | * If the computed checksum is zero, it is transmitted as all ones (the equivalent in one's complement arithmetic). |
184 | * If the computed checksum is zero, it is transmitted as all ones (the equivalent in one's complement arithmetic). |
144 | */ |
185 | */ |
145 | uint16_t check; |
186 | uint16_t checksum; |
- | 187 | /** This field communicates the current value of the urgent pointer as a~positive offset from the sequence number in this segment. |
|
146 | /** Points to the first data octet following the urgent data. |
188 | * The urgent pointer points to the sequence number of the octet following the urgent data. |
147 | * Only significant when the URG control bit is set. |
189 | * This field is only be interpreted in segments with the URG control bit set. |
- | 190 | * @see tcp_header:urgent |
|
- | 191 | */ |
|
- | 192 | uint16_t urgent_pointer; |
|
- | 193 | } __attribute__ ((packed)); |
|
- | 194 | ||
- | 195 | /** Transmission datagram header option. |
|
- | 196 | */ |
|
- | 197 | struct tcp_option{ |
|
- | 198 | /** Option type. |
|
- | 199 | */ |
|
- | 200 | uint8_t type; |
|
- | 201 | /** Option length. |
|
- | 202 | */ |
|
- | 203 | uint8_t length; |
|
- | 204 | }; |
|
- | 205 | ||
- | 206 | /** Maximum segment size TCP option. |
|
- | 207 | */ |
|
- | 208 | struct tcp_max_segment_size_option{ |
|
- | 209 | /** TCP option. |
|
- | 210 | * @see TCPOPT_MAX_SEGMENT_SIZE |
|
- | 211 | * @see TCPOPT_MAX_SEGMENT_SIZE_LENGTH |
|
- | 212 | */ |
|
- | 213 | tcp_option_t option; |
|
- | 214 | /** Maximum segment size in bytes. |
|
148 | */ |
215 | */ |
149 | uint16_t urg_ptr; |
216 | uint16_t max_segment_size; |
150 | } __attribute__ ((packed)); |
217 | } __attribute__ ((packed)); |
151 | 218 | ||
152 | #endif |
219 | #endif |
153 | 220 | ||
154 | /** @} |
221 | /** @} |