net.h
/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License.
 *
 * This program 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.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) Guido Socher
 * All rights reserved.
 *
 * Original Author: Guido Socher
 * Contributor(s): nuelectronics.com -- Ethershield for Arduino
 *                 Sergey Sharybin -- PIC18F4550 adoptation
 *
 * IP, Arp, UDP and TCP functions.
 *
 * The TCP implementation uses some size optimisations which are valid
 * only if all data can be sent in one single packet. This is however
 * not a big limitation for a microcontroller as you will anyhow use
 * small web-pages. The TCP stack is therefore a SDP-TCP stack
 * (single data packet TCP).
 */

#ifndef __NET_H__
#define __NET_H__

#include <stdint.h>

/* Notation: _P = position of a field
 *           _V = value of a field
 */

/* ******* ETH ******* */
#define ETH_HEADER_LEN  14
/* values of certain bytes. */
#define ETHTYPE_ARP_H_V 0x08
#define ETHTYPE_ARP_L_V 0x06
#define ETHTYPE_IP_V    0x0800
#define ETHTYPE_IP_H_V  0x08
#define ETHTYPE_IP_L_V  0x00
/* Byte positions in the ethernet frame. */
/* Ethernet type field (2bytes) */
#define ETH_TYPE_H_P 12
#define ETH_TYPE_L_P 13

#define ETH_DST_MAC 0
#define ETH_SRC_MAC 6


/* ******* ARP ******* */
#define ETH_ARP_OPCODE_REPLY_H_V 0x0
#define ETH_ARP_OPCODE_REPLY_L_V 0x02
#define ETHTYPE_ARP_L_V         0x06
/* arp.dst.ip */
#define ETH_ARP_DST_IP_P        0x26
/* arp.opcode */
#define ETH_ARP_OPCODE_H_P      0x14
#define ETH_ARP_OPCODE_L_P      0x15
/* arp.src.mac */
#define ETH_ARP_SRC_MAC_P       0x16
#define ETH_ARP_SRC_IP_P        0x1c
#define ETH_ARP_DST_MAC_P       0x20
#define ETH_ARP_DST_IP_P        0x26

#define ARP_OPCODE_REQUEST_H_V  0x00
#define ARP_OPCODE_REQUEST_L_V  0x01
#define ARP_OPCODE_REPLY_H_V    0x00
#define ARP_OPCODE_REPLY_L_V    0x02

#define ARP_HARDWARE_TYPE_H_V   0x00
#define ARP_HARDWARE_TYPE_L_V   0x01
#define ARP_PROTOCOL_H_V        0x08
#define ARP_PROTOCOL_L_V        0x00
#define ARP_HARDWARE_SIZE_V     0x06
#define ARP_PROTOCOL_SIZE_V     0x04

#define ARP_HARDWARE_TYPE_H_P   0x0E
#define ARP_HARDWARE_TYPE_L_P   0x0F
#define ARP_PROTOCOL_H_P        0x10
#define ARP_PROTOCOL_L_P        0x11
#define ARP_HARDWARE_SIZE_P     0x12
#define ARP_PROTOCOL_SIZE_P     0x13
#define ARP_OPCODE_H_P          0x14
#define ARP_OPCODE_L_P          0x15
#define ARP_SRC_MAC_P           0x16
#define ARP_SRC_IP_P            0x1C
#define ARP_DST_MAC_P           0x20
#define ARP_DST_IP_P            0x26

/* ******* IP ******* */
#define IP_HEADER_LEN           20

#define IP_PROTO_ICMP_V         0x01
#define IP_PROTO_TCP_V          0x06
#define IP_PROTO_UDP_V          0x11
#define IP_V4_V                 0x40
#define IP_HEADER_LENGTH_V      0x05

#define IP_P                    0x0E
#define IP_HEADER_VER_LEN_P     0x0E
#define IP_TOS_P                0x0F
#define IP_TOTLEN_H_P           0x10
#define IP_TOTLEN_L_P           0x11
#define IP_ID_H_P               0x12
#define IP_ID_L_P               0x13
#define IP_FLAGS_P              0x14
#define IP_FLAGS_H_P            0x14
#define IP_FLAGS_L_P            0x15
#define IP_TTL_P                0x16
#define IP_PROTO_P              0x17
#define IP_CHECKSUM_P           0x18
#define IP_CHECKSUM_H_P         0x18
#define IP_CHECKSUM_L_P         0x19
#define IP_SRC_IP_P             0x1A
#define IP_DST_IP_P             0x1E

#define IP_SRC_P                0x1a
#define IP_DST_P                0x1e
#define IP_HEADER_LEN_VER_P 0xe

/* ******* ICMP ******* */
#define ICMP_TYPE_ECHOREPLY_V   0
#define ICMP_TYPE_ECHOREQUEST_V 8
#define ICMP_TYPE_P 0x22
#define ICMP_CHECKSUM_P 0x24

/* ******* UDP ******* */
#define UDP_HEADER_LEN          8
#define UDP_SRC_PORT_H_P        0x22
#define UDP_SRC_PORT_L_P        0x23
#define UDP_DST_PORT_H_P        0x24
#define UDP_DST_PORT_L_P        0x25
#define UDP_LEN_H_P             0x26
#define UDP_LEN_L_P             0x27
#define UDP_CHECKSUM_H_P        0x28
#define UDP_CHECKSUM_L_P        0x29
#define UDP_DATA_P              0x2a

/* ******* TCP ******* */
/*  plain len without the options. */
#define TCP_HEADER_LEN_PLAIN 20


#define TCP_FLAG_FIN_V          0x01
#define TCP_FLAGS_FIN_V         0x01
#define TCP_FLAGS_SYN_V         0x02
#define TCP_FLAG_SYN_V          0x02
#define TCP_FLAG_RST_V          0x04
#define TCP_FLAG_PUSH_V         0x08
#define TCP_FLAGS_ACK_V         0x10
#define TCP_FLAG_ACK_V          0x10
#define TCP_FLAG_URG_V          0x20
#define TCP_FLAG_ECE_V          0x40
#define TCP_FLAG_CWR_V          0x80
#define TCP_FLAGS_SYNACK_V      0x12

#define TCP_SRC_PORT_H_P        0x22
#define TCP_SRC_PORT_L_P        0x23
#define TCP_DST_PORT_H_P        0x24
#define TCP_DST_PORT_L_P        0x25
/* the tcp seq number is 4 bytes 0x26-0x29 */
#define TCP_SEQ_P               0x26
#define TCP_SEQ_H_P             0x26
#define TCP_SEQACK_P            0x2A  /* 4 bytes */
#define TCP_SEQACK_H_P          0x2A
#define TCP_HEADER_LEN_P        0x2E
#define TCP_FLAGS_P             0x2F
#define TCP_FLAG_P              0x2F
#define TCP_WINDOWSIZE_H_P      0x30  /* 2 bytes */
#define TCP_WINDOWSIZE_L_P      0x31
#define TCP_CHECKSUM_H_P        0x32
#define TCP_CHECKSUM_L_P        0x33
#define TCP_URGENT_PTR_H_P      0x34  /* 2 bytes */
#define TCP_URGENT_PTR_L_P      0x35
#define TCP_OPTIONS_P           0x36
#define TCP_DATA_P              0x36

void NET_init(uint8_t *mac_addr, uint8_t *ip_addr, uint8_t port);

uint8_t NET_eth_type_is_arp_and_my_ip(uint8_t *buf, uint16_t len);
uint8_t NET_eth_type_is_ip_and_my_ip(uint8_t *buf, uint16_t len);
void NET_make_arp_answer_from_request(uint8_t *buf);
void NET_make_echo_reply_from_request(uint8_t *buf, uint16_t len);
void NET_make_udp_reply_from_request(uint8_t *buf,
                                     char *data,
                                     uint8_t datalen,
                                     uint16_t port);

void NET_make_tcp_synack_from_syn(uint8_t *buf);
void NET_init_len_info(uint8_t *buf);
uint16_t NET_get_tcp_data_pointer(void);
uint16_t NET_fill_tcp_data_p(uint8_t *buf,
                             uint16_t pos,
                             const char *progmem_s);
uint16_t NET_fill_tcp_data(uint8_t *buf,
                           uint16_t pos,
                           const char *s);
void NET_make_tcp_ack_from_any(uint8_t *buf);
void NET_make_tcp_ack_with_data(uint8_t *buf, uint16_t len);
void NET_make_arp_request(uint8_t *buf, uint8_t *server_ip);
uint8_t NET_arp_packet_is_myreply_arp(uint8_t *buf);
void NET_tcp_client_send_packet(uint8_t *buf,
                                uint16_t dest_port,
                                uint16_t src_port,
                                uint8_t flags,
                                uint8_t max_segment_size,
                                uint8_t clear_seqck,
                                uint16_t next_ack_num,
                                uint16_t dlength,
                                uint8_t *dest_mac,
                                uint8_t *dest_ip);
uint16_t NET_tcp_get_dlength(uint8_t *buf);

#endif  /* __NET_H__ */