Ipv4Tcp.h

/*
Copyright (C) <2010-2011> Karl Hiramoto <karl@hiramoto.org>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

#ifndef IPV4_H
#define IPV4_H 1

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <netinet/in.h>
#include <linux/tcp.h>
#include <linux/netlink.h>
#include <ubiqx/ubi_dLinkList.h>

/**
* @defgroup Ipv4Tcp  TCP/IP version 4 defintions
* @{
*/

#define HTTP_TCP_PORT 80
#define TCP_FLAG_SET(p,loc,flag) ((((int) *((int*) &p->ip_data[loc])) & flag) & __cpu_to_be32(0x00FF0000))

//byte offset int TCP header
#define TCP_FLAG_OFFSET 12

#define TCP_SEQ_HI_WRAPZONE 0xFFFFFFFF - 1500

struct Ipv4TcpTuple {
	in_addr_t src_ip;
	in_addr_t dst_ip;
	in_port_t src_port; // 16 bit port
	in_port_t dst_port;
};

/**
* TCP/IP version 4 packet.
* It can be a member of a linked list
*/
struct Ipv4TcpPkt {
	ubi_dlNode node;	/** ubiqx "internal" data */
	struct Ipv4TcpTuple tuple;
	uint32_t packet_id; /**< Linux Netlink Packet ID number */
	uint32_t seq_num; /**< TCP Sequence number */
	uint32_t ack_num; /**< TCP ACK number */
	uint32_t tcp_flags; /**< 8 bits of tcp flags but use 32bit so we are machine size and use linux macros */
	uint16_t ip_checksum; /**< IP header checksum */
	uint16_t tcp_checksum; /**< TCP checksum */
	uint16_t ip_packet_length; /**< Length of IP packet */
	uint16_t tcp_payload_length; /**< Length of TCP payload */
	void *nl_buffer;  /**< pointer to raw netlink message buffer. */
	uint8_t *ip_data; /**< pointer to raw IP packet data */
	uint8_t *tcp_payload; /**< pointer within data to TCP payload */
	struct nfnl_queue_msg *nl_qmsg;
	uint8_t ip_hdr_len;
	uint8_t *modified_ip_data; /**< if not NULL the payload has been modified */
	unsigned int modified_ip_data_len;
};

unsigned short get_cksum16(const unsigned short *data, int len, int csum);

void Ipv4TcpPkt_resetTcpCksum(unsigned char *ip_pkt, unsigned int ip_pkt_size, unsigned int ip_hdr_len);

struct Ipv4TcpPkt *Ipv4TcpPkt_new(unsigned nl_buff_size);
void Ipv4TcpPkt_del(struct Ipv4TcpPkt **pkt);
struct Ipv4TcpPkt * Ipv4TcpPkt_clone(struct Ipv4TcpPkt *in_pkt, bool copy_packet_data);

int Ipv4TcpPkt_parseNlHdrMsg(struct Ipv4TcpPkt *pkt, struct nlmsghdr *nlh);
int Ipv4TcpPkt_parseIpPayload(struct Ipv4TcpPkt *pkt);
int Ipv4TcpPkt_printPkt(struct Ipv4TcpPkt *pkt, FILE *stream);

void Ipv4TcpPkt_setTcpFlag(struct Ipv4TcpPkt *pkt, int flag_val);
void Ipv4TcpPkt_clearTcpFlag(struct Ipv4TcpPkt *pkt, int flag_val);

// void Ipv4TcpPkt_setNlVerictAccept(struct Ipv4TcpPkt *pkt);
void Ipv4TcpPkt_setNlVerictDrop(struct Ipv4TcpPkt *pkt);

void Ipv4TcpPkt_resetTcpCon(struct Ipv4TcpPkt *pkt);
void print_hex(const unsigned char* payload, int len);

void Ipv4TcpPkt_setMark(struct Ipv4TcpPkt *pkt, uint32_t mark, uint32_t mask);

/** @}  */

#endif