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/***************************************************************************
* TCPHeader.h -- The TCPHeader Class represents a TCP packet. It contains *
* methods to set the different header fields. These methods tipically *
* perform the necessary error checks and byte order conversions. *
* *
***********************IMPORTANT NMAP LICENSE TERMS************************
*
* The Nmap Security Scanner is (C) 1996-2023 Nmap Software LLC ("The Nmap
* Project"). Nmap is also a registered trademark of the Nmap Project.
*
* This program is distributed under the terms of the Nmap Public Source
* License (NPSL). The exact license text applying to a particular Nmap
* release or source code control revision is contained in the LICENSE
* file distributed with that version of Nmap or source code control
* revision. More Nmap copyright/legal information is available from
* https://nmap.org/book/man-legal.html, and further information on the
* NPSL license itself can be found at https://nmap.org/npsl/ . This
* header summarizes some key points from the Nmap license, but is no
* substitute for the actual license text.
*
* Nmap is generally free for end users to download and use themselves,
* including commercial use. It is available from https://nmap.org.
*
* The Nmap license generally prohibits companies from using and
* redistributing Nmap in commercial products, but we sell a special Nmap
* OEM Edition with a more permissive license and special features for
* this purpose. See https://nmap.org/oem/
*
* If you have received a written Nmap license agreement or contract
* stating terms other than these (such as an Nmap OEM license), you may
* choose to use and redistribute Nmap under those terms instead.
*
* The official Nmap Windows builds include the Npcap software
* (https://npcap.com) for packet capture and transmission. It is under
* separate license terms which forbid redistribution without special
* permission. So the official Nmap Windows builds may not be redistributed
* without special permission (such as an Nmap OEM license).
*
* Source is provided to this software because we believe users have a
* right to know exactly what a program is going to do before they run it.
* This also allows you to audit the software for security holes.
*
* Source code also allows you to port Nmap to new platforms, fix bugs, and add
* new features. You are highly encouraged to submit your changes as a Github PR
* or by email to the dev@nmap.org mailing list for possible incorporation into
* the main distribution. Unless you specify otherwise, it is understood that
* you are offering us very broad rights to use your submissions as described in
* the Nmap Public Source License Contributor Agreement. This is important
* because we fund the project by selling licenses with various terms, and also
* because the inability to relicense code has caused devastating problems for
* other Free Software projects (such as KDE and NASM).
*
* The free version of Nmap is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Warranties,
* indemnification and commercial support are all available through the
* Npcap OEM program--see https://nmap.org/oem/
*
***************************************************************************/
/* This code was originally part of the Nping tool. */
#ifndef __TCPHEADER_H__
#define __TCPHEADER_H__ 1
#include "TransportLayerElement.h"
/* TCP FLAGS */
#define TH_FIN 0x01
#define TH_SYN 0x02
#define TH_RST 0x04
#define TH_PSH 0x08
#define TH_ACK 0x10
#define TH_URG 0x20
#define TH_ECN 0x40
#define TH_CWR 0x80
/* TCP OPTIONS */
#define TCPOPT_EOL 0 /* End of Option List (RFC793) */
#define TCPOPT_NOOP 1 /* No-Operation (RFC793) */
#define TCPOPT_MSS 2 /* Maximum Segment Size (RFC793) */
#define TCPOPT_WSCALE 3 /* WSOPT - Window Scale (RFC1323) */
#define TCPOPT_SACKOK 4 /* SACK Permitted (RFC2018) */
#define TCPOPT_SACK 5 /* SACK (RFC2018) */
#define TCPOPT_ECHOREQ 6 /* Echo (obsolete) (RFC1072)(RFC6247) */
#define TCPOPT_ECHOREP 7 /* Echo Reply (obsolete) (RFC1072)(RFC6247) */
#define TCPOPT_TSTAMP 8 /* TSOPT - Time Stamp Option (RFC1323) */
#define TCPOPT_POCP 9 /* Partial Order Connection Permitted (obsol.) */
#define TCPOPT_POSP 10 /* Partial Order Service Profile (obsolete) */
#define TCPOPT_CC 11 /* CC (obsolete) (RFC1644)(RFC6247) */
#define TCPOPT_CCNEW 12 /* CC.NEW (obsolete) (RFC1644)(RFC6247) */
#define TCPOPT_CCECHO 13 /* CC.ECHO (obsolete) (RFC1644)(RFC6247) */
#define TCPOPT_ALTCSUMREQ 14 /* TCP Alternate Checksum Request (obsolete) */
#define TCPOPT_ALTCSUMDATA 15 /* TCP Alternate Checksum Data (obsolete) */
#define TCPOPT_MD5 19 /* MD5 Signature Option (obsolete) (RFC2385) */
#define TCPOPT_SCPS 20 /* SCPS Capabilities */
#define TCPOPT_SNACK 21 /* Selective Negative Acknowledgements */
#define TCPOPT_QSRES 27 /* Quick-Start Response (RFC4782) */
#define TCPOPT_UTO 28 /* User Timeout Option (RFC5482) */
#define TCPOPT_AO 29 /* TCP Authentication Option (RFC5925) */
/* Internal constants */
#define TCP_HEADER_LEN 20
#define MAX_TCP_OPTIONS_LEN 40
#define MAX_TCP_PAYLOAD_LEN 65495 /**< Max len of a TCP packet */
/* Default header values */
#define TCP_DEFAULT_SPORT 20
#define TCP_DEFAULT_DPORT 80
#define TCP_DEFAULT_SEQ 0
#define TCP_DEFAULT_ACK 0
#define TCP_DEFAULT_FLAGS 0x02
#define TCP_DEFAULT_WIN 8192
#define TCP_DEFAULT_URP 0
/*
+--------+--------+---------+--------...
| Type | Len | Value
+--------+--------+---------+--------...
*/
struct nping_tcp_opt {
u8 type; /* Option type code. */
u8 len; /* Option length. */
u8 *value; /* Option value */
}__attribute__((__packed__));
typedef struct nping_tcp_opt nping_tcp_opt_t;
class TCPHeader : public TransportLayerElement {
private:
/*
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Port | Destination Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Acknowledgment Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Offset| Res. |C|E|U|A|P|R|S|F| Window |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Checksum | Urgent Pointer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
struct nping_tcp_hdr {
u16 th_sport; /* Source port */
u16 th_dport; /* Destination port */
u32 th_seq; /* Sequence number */
u32 th_ack; /* Acknowledgement number */
#if WORDS_BIGENDIAN
u8 th_off:4; /* Data offset */
u8 th_x2:4; /* Reserved */
#else
u8 th_x2:4; /* Reserved */
u8 th_off:4; /* Data offset */
#endif
u8 th_flags; /* Flags */
u16 th_win; /* Window size */
u16 th_sum; /* Checksum */
u16 th_urp; /* Urgent pointer */
u8 options[MAX_TCP_OPTIONS_LEN ]; /* Space for TCP Options */
}__attribute__((__packed__));
typedef struct nping_tcp_hdr nping_tcp_hdr_t;
nping_tcp_hdr_t h;
int tcpoptlen; /**< Length of TCP options */
void __tcppacketoptinfo(const u8 *optp, int len, char *result, int bufsize) const;
public:
TCPHeader();
~TCPHeader();
void reset();
u8 *getBufferPointer();
int storeRecvData(const u8 *buf, size_t len);
int protocol_id() const;
int validate();
int print(FILE *output, int detail) const;
int setSourcePort(u16 p);
u16 getSourcePort() const;
int setDestinationPort(u16 p);
u16 getDestinationPort() const;
int setSeq(u32 p);
u32 getSeq() const;
int setAck(u32 p);
u32 getAck() const;
int setOffset(u8 o);
int setOffset();
u8 getOffset() const;
int setReserved(u8 r);
u8 getReserved() const;
int setFlags(u8 f);
u8 getFlags() const;
u16 getFlags16() const;
bool setCWR();
bool unsetCWR();
bool getCWR() const;
bool setECE();
bool unsetECE();
bool getECE() const;
bool setECN();
bool unsetECN();
bool getECN() const;
bool setURG();
bool unsetURG();
bool getURG() const;
bool setACK();
bool unsetACK();
bool getACK() const;
bool setPSH();
bool unsetPSH();
bool getPSH() const;
bool setRST();
bool unsetRST();
bool getRST() const;
bool setSYN();
bool unsetSYN();
bool getSYN() const;
bool setFIN();
bool unsetFIN();
bool getFIN() const;
int setWindow(u16 p);
u16 getWindow() const;
int setUrgPointer(u16 l);
u16 getUrgPointer() const;
int setSum(u16 s);
int setSum(struct in_addr source, struct in_addr destination);
int setSum();
int setSumRandom();
int setSumRandom(struct in_addr source, struct in_addr destination);
u16 getSum() const;
int setOptions(const u8 *optsbuff, size_t optslen);
const u8 *getOptions(size_t *optslen) const;
nping_tcp_opt_t getOption(unsigned int index) const;
static const char *optcode2str(u8 optcode);
}; /* End of class TCPHeader */
#endif /* __TCPHEADER_H__ */
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