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94/*
* Copyright (c) 2016 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef included_tcp_packet_h
#define included_tcp_packet_h
#include <vnet/vnet.h>
/* TCP flags bit 0 first. */
#define foreach_tcp_flag \
_ (FIN) /**< No more data from sender. */ \
_ (SYN) /**< Synchronize sequence numbers. */ \
_ (RST) /**< Reset the connection. */ \
_ (PSH) /**< Push function. */ \
_ (ACK) /**< Ack field significant. */ \
_ (URG) /**< Urgent pointer field significant. */ \
_ (ECE) /**< ECN-echo. Receiver got CE packet */ \
_ (CWR) /**< Sender reduced congestion window */
enum
{
#define _(f) TCP_FLAG_BIT_##f,
foreach_tcp_flag
#undef _
TCP_N_FLAG_BITS,
};
enum
{
#define _(f) TCP_FLAG_##f = 1 << TCP_FLAG_BIT_##f,
foreach_tcp_flag
#undef _
};
typedef struct _tcp_header
{
union
{
struct
{
u16 src_port; /**< Source port. */
u16 dst_port; /**< Destination port. */
};
struct
{
u16 src, dst;
};
};
u32 seq_number; /**< Sequence number of the first data octet in this
* segment, except when SYN is present. If SYN
* is present the seq number is is the ISN and the
* first data octet is ISN+1 */
u32 ack_number; /**< Acknowledgement number if ACK is set. It contains
* the value of the next sequence number the sender
* of the segment is expecting to receive. */
u8 data_offset_and_reserved;
u8 flags; /**< Flags: see the macro above */
u16 window; /**< Number of bytes sender is willing to receive. */
u16 checksum; /**< Checksum of TCP pseudo header and data. */
u16 urgent_pointer; /**< Seq number of the byte after the urgent data. */
} __attribute__ ((packed)) tcp_header_t;
/* Flag tests that return 0 or !0 */
#define tcp_doff(_th) ((_th)->data_offset_and_reserved >> 4)
#define tcp_fin(_th) ((_th)->flags & TCP_FLAG_FIN)
#define tcp_syn(_th) ((_th)->flags & TCP_FLAG_SYN)
#define tcp_rst(_th) ((_th)->flags & TCP_FLAG_RST)
#define tcp_psh(_th) ((_th)->flags & TCP_FLAG_PSH)
#define tcp_ack(_th) ((_th)->flags & TCP_FLAG_ACK)
#define tcp_urg(_th) ((_th)->flags & TCP_FLAG_URG)
#define tcp_ece(_th) ((_th)->flags & TCP_FLAG_ECE)
#define tcp_cwr(_th) ((_th)->flags & TCP_FLAG_CWR)
/* Flag tests that return 0 or 1 */
#define tcp_is_syn(_th) !!((_th)->flags & TCP_FLAG_SYN)
#define tcp_is_fin(_th) !!((_th)->flags & TCP_FLAG_FIN)
always_inline int
tcp_header_bytes (tcp_header_t * t)
{
return tcp_doff (t) * sizeof (u32);
}
/*
* TCP options.
*/
typedef enum tcp_option_type
{
TCP_OPTION_EOL = 0, /**< End of options. */
TCP_OPTION_NOOP = 1, /**< No operation. */
TCP_OPTION_MSS = 2, /**< Limit MSS. */
TCP_OPTION_WINDOW_SCALE = 3, /**< Window scale. */
TCP_OPTION_SACK_PERMITTED = 4, /**< Selective Ack permitted. */
TCP_OPTION_SACK_BLOCK = 5, /**< Selective Ack block. */
TCP_OPTION_TIMESTAMP = 8, /**< Timestamps. */
TCP_OPTION_UTO = 28, /**< User timeout. */
TCP_OPTION_AO = 29, /**< Authentication Option. */
} tcp_option_type_t;
#define foreach_tcp_options_flag \
_ (MSS) /**< MSS advertised in SYN */ \
_ (TSTAMP) /**< Timestamp capability advertised in SYN */ \
_ (WSCALE) /**< Wnd scale capability advertised in SYN */ \
_ (SACK_PERMITTED) /**< SACK capability advertised in SYN */ \
_ (SACK) /**< SACK present */
enum
{
#define _(f) TCP_OPTS_FLAG_BIT_##f,
foreach_tcp_options_flag
#undef _
TCP_OPTIONS_N_FLAG_BITS,
};
enum
{
#define _(f) TCP_OPTS_FLAG_##f = 1 << TCP_OPTS_FLAG_BIT_##f,
foreach_tcp_options_flag
#undef _
};
typedef struct _sack_block
{
u32 start; /**< Start sequence number */
u32 end; /**< End sequence number (first outside) */
} sack_block_t;
typedef struct
{
u8 flags; /** Option flags, see above */
u16 mss; /**< Maximum segment size advertised */
u8 wscale; /**< Window scale advertised */
u32 tsval; /**< Timestamp value */
u32 tsecr; /**< Echoed/reflected time stamp */
sack_block_t *sacks; /**< SACK blocks */
u8 n_sack_blocks; /**< Number of SACKs blocks */
} tcp_options_t;
/* Flag tests that return 0 or !0 */
#define tcp_opts_mss(_to) ((_to)->flags & TCP_OPTS_FLAG_MSS)
#define tcp_opts_tstamp(_to) ((_to)->flags & TCP_OPTS_FLAG_TSTAMP)
#define tcp_opts_wscale(_to) ((_to)->flags & TCP_OPTS_FLAG_WSCALE)
#define tcp_opts_sack(_to) ((_to)->flags & TCP_OPTS_FLAG_SACK)
#define tcp_opts_sack_permitted(_to) ((_to)->flags & TCP_OPTS_FLAG_SACK_PERMITTED)
/* TCP option lengths */
#define TCP_OPTION_LEN_EOL 1
#define TCP_OPTION_LEN_NOOP 1
#define TCP_OPTION_LEN_MSS 4
#define TCP_OPTION_LEN_WINDOW_SCALE 3
#define TCP_OPTION_LEN_SACK_PERMITTED 2
#define TCP_OPTION_LEN_TIMESTAMP 10
#define TCP_OPTION_LEN_SACK_BLOCK 8
#define TCP_HDR_LEN_MAX 60
#define TCP_WND_MAX 65535U
#define TCP_MAX_WND_SCALE 14 /* See RFC 1323 */
#define TCP_OPTS_ALIGN 4
#define TCP_OPTS_MAX_SACK_BLOCKS 3
#endif /* included_tcp_packet_h */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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