2 * Copyright (c) 2016-2019 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
16 #ifndef included_tcp_packet_h
17 #define included_tcp_packet_h
19 #include <vnet/vnet.h>
21 /* TCP flags bit 0 first. */
22 #define foreach_tcp_flag \
23 _ (FIN) /**< No more data from sender. */ \
24 _ (SYN) /**< Synchronize sequence numbers. */ \
25 _ (RST) /**< Reset the connection. */ \
26 _ (PSH) /**< Push function. */ \
27 _ (ACK) /**< Ack field significant. */ \
28 _ (URG) /**< Urgent pointer field significant. */ \
29 _ (ECE) /**< ECN-echo. Receiver got CE packet */ \
30 _ (CWR) /**< Sender reduced congestion window */
34 #define _(f) TCP_FLAG_BIT_##f,
42 #define _(f) TCP_FLAG_##f = 1 << TCP_FLAG_BIT_##f,
47 typedef struct _tcp_header
53 u16 src_port; /**< Source port. */
54 u16 dst_port; /**< Destination port. */
62 u32 seq_number; /**< Sequence number of the first data octet in this
63 * segment, except when SYN is present. If SYN
64 * is present the seq number is is the ISN and the
65 * first data octet is ISN+1 */
66 u32 ack_number; /**< Acknowledgement number if ACK is set. It contains
67 * the value of the next sequence number the sender
68 * of the segment is expecting to receive. */
69 u8 data_offset_and_reserved;
70 u8 flags; /**< Flags: see the macro above */
71 u16 window; /**< Number of bytes sender is willing to receive. */
73 u16 checksum; /**< Checksum of TCP pseudo header and data. */
74 u16 urgent_pointer; /**< Seq number of the byte after the urgent data. */
75 } __attribute__ ((packed)) tcp_header_t;
77 /* Flag tests that return 0 or !0 */
78 #define tcp_doff(_th) ((_th)->data_offset_and_reserved >> 4)
79 #define tcp_fin(_th) ((_th)->flags & TCP_FLAG_FIN)
80 #define tcp_syn(_th) ((_th)->flags & TCP_FLAG_SYN)
81 #define tcp_rst(_th) ((_th)->flags & TCP_FLAG_RST)
82 #define tcp_psh(_th) ((_th)->flags & TCP_FLAG_PSH)
83 #define tcp_ack(_th) ((_th)->flags & TCP_FLAG_ACK)
84 #define tcp_urg(_th) ((_th)->flags & TCP_FLAG_URG)
85 #define tcp_ece(_th) ((_th)->flags & TCP_FLAG_ECE)
86 #define tcp_cwr(_th) ((_th)->flags & TCP_FLAG_CWR)
88 /* Flag tests that return 0 or 1 */
89 #define tcp_is_syn(_th) !!((_th)->flags & TCP_FLAG_SYN)
90 #define tcp_is_fin(_th) !!((_th)->flags & TCP_FLAG_FIN)
93 tcp_header_bytes (tcp_header_t * t)
95 return tcp_doff (t) * sizeof (u32);
102 typedef enum tcp_option_type
104 TCP_OPTION_EOL = 0, /**< End of options. */
105 TCP_OPTION_NOOP = 1, /**< No operation. */
106 TCP_OPTION_MSS = 2, /**< Limit MSS. */
107 TCP_OPTION_WINDOW_SCALE = 3, /**< Window scale. */
108 TCP_OPTION_SACK_PERMITTED = 4, /**< Selective Ack permitted. */
109 TCP_OPTION_SACK_BLOCK = 5, /**< Selective Ack block. */
110 TCP_OPTION_TIMESTAMP = 8, /**< Timestamps. */
111 TCP_OPTION_UTO = 28, /**< User timeout. */
112 TCP_OPTION_AO = 29, /**< Authentication Option. */
115 #define foreach_tcp_options_flag \
116 _ (MSS) /**< MSS advertised in SYN */ \
117 _ (TSTAMP) /**< Timestamp capability advertised in SYN */ \
118 _ (WSCALE) /**< Wnd scale capability advertised in SYN */ \
119 _ (SACK_PERMITTED) /**< SACK capability advertised in SYN */ \
120 _ (SACK) /**< SACK present */
124 #define _(f) TCP_OPTS_FLAG_BIT_##f,
125 foreach_tcp_options_flag
127 TCP_OPTIONS_N_FLAG_BITS,
132 #define _(f) TCP_OPTS_FLAG_##f = 1 << TCP_OPTS_FLAG_BIT_##f,
133 foreach_tcp_options_flag
137 typedef struct _sack_block
139 u32 start; /**< Start sequence number */
140 u32 end; /**< End sequence number (first outside) */
145 u8 flags; /** Option flags, see above */
146 u8 wscale; /**< Window scale advertised */
147 u16 mss; /**< Maximum segment size advertised */
148 u32 tsval; /**< Timestamp value */
149 u32 tsecr; /**< Echoed/reflected time stamp */
150 sack_block_t *sacks; /**< SACK blocks */
151 u8 n_sack_blocks; /**< Number of SACKs blocks */
154 /* Flag tests that return 0 or !0 */
155 #define tcp_opts_mss(_to) ((_to)->flags & TCP_OPTS_FLAG_MSS)
156 #define tcp_opts_tstamp(_to) ((_to)->flags & TCP_OPTS_FLAG_TSTAMP)
157 #define tcp_opts_wscale(_to) ((_to)->flags & TCP_OPTS_FLAG_WSCALE)
158 #define tcp_opts_sack(_to) ((_to)->flags & TCP_OPTS_FLAG_SACK)
159 #define tcp_opts_sack_permitted(_to) ((_to)->flags & TCP_OPTS_FLAG_SACK_PERMITTED)
161 /* TCP option lengths */
162 #define TCP_OPTION_LEN_EOL 1
163 #define TCP_OPTION_LEN_NOOP 1
164 #define TCP_OPTION_LEN_MSS 4
165 #define TCP_OPTION_LEN_WINDOW_SCALE 3
166 #define TCP_OPTION_LEN_SACK_PERMITTED 2
167 #define TCP_OPTION_LEN_TIMESTAMP 10
168 #define TCP_OPTION_LEN_SACK_BLOCK 8
170 #define TCP_HDR_LEN_MAX 60
171 #define TCP_WND_MAX 65535U
172 #define TCP_MAX_WND_SCALE 14 /* See RFC 1323 */
173 #define TCP_OPTS_ALIGN 4
174 #define TCP_OPTS_MAX_SACK_BLOCKS 3
175 #endif /* included_tcp_packet_h */
178 * fd.io coding-style-patch-verification: ON
181 * eval: (c-set-style "gnu")