/********************************************* * vim:sw=8:ts=8:si:et * To use the above modeline in vim you must have "set modeline" in your .vimrc * * Author: Guido Socher  * Copyright: GPL V2 * See http://www.gnu.org/licenses/gpl.html * * 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). * * Chip type           : ATMEGA88 with ENC28J60 *********************************************//*

                         \\\|///
                       \\  - -  //
                        (  @ @  )
+---------------------oOOo-(_)-oOOo-------------------------+
|                       WEB SERVER                          |
|            ported to LPC2103 ARM7TDMI-S CPU               |
|                     by Xiaoran Liu                        |
|                       2007.12.16                          |
|                 ZERO research Instutute                   |
|                      www.the0.net                         |
|                            Oooo                           |
+----------------------oooO--(   )--------------------------+
                      (   )   ) /
                       \ (   (_/
                        \_)     

*/

#include "net.h"#include "enc28j60.h"
#define  pgm_read_byte(ptr)  ((char)*(ptr))
static uint8_t wwwport=80;static uint8_t macaddr[6];static uint8_t ipaddr[4];static int16_t info_hdr_len=0;static int16_t info_data_len=0;static uint8_t seqnum=0xa; // my initial tcp sequence number// The Ip checksum is calculated over the ip header only starting// with the header length field and a total length of 20 bytes// unitl ip.dst// You must set the IP checksum field to zero before you start// the calculation.// len for ip is 20.//// For UDP/TCP we do not make up the required pseudo header. Instead we // use the ip.src and ip.dst fields of the real packet:// The udp checksum calculation starts with the ip.src field// Ip.src=4bytes,Ip.dst=4 bytes,Udp header=8bytes + data length=16+len// In other words the len here is 8 + length over which you actually// want to calculate the checksum.// You must set the checksum field to zero before you start// the calculation.// len for udp is: 8 + 8 + data length// len for tcp is: 4+4 + 20 + option len + data length//// For more information on how this algorithm works see:// http://www.netfor2.com/checksum.html// http://www.msc.uky.edu/ken/cs471/notes/chap3.htm// The RFC has also a C code example: http://www.faqs.org/rfcs/rfc1071.htmluint16_t checksum(uint8_t *buf, uint16_t len,uint8_t type){        // type 0=ip         //      1=udp        //      2=tcp        uint32_t sum = 0;        //if(type==0){        //        // do not add anything        //}        if(type==1){                sum+=IP_PROTO_UDP_V; // protocol udp                // the length here is the length of udp (data+header len)                // =length given to this function - (IP.scr+IP.dst length)                sum+=len-8; // = real tcp len        }        if(type==2){                sum+=IP_PROTO_TCP_V;                 // the length here is the length of tcp (data+header len)                // =length given to this function - (IP.scr+IP.dst length)                sum+=len-8; // = real tcp len        }        // build the sum of 16bit words        while(len >1){                sum += 0xFFFF & (((uint32_t)*buf<<8)|*(buf+1));                buf+=2;                len-=2;        }        // if there is a byte left then add it (padded with zero)        if (len){                sum += ((uint32_t)(0xFF & *buf))<<8;        }        // now calculate the sum over the bytes in the sum        // until the result is only 16bit long        while (sum>>16){                sum = (sum & 0xFFFF)+(sum >> 16);        }        // build 1's complement:        return( (uint16_t) sum ^ 0xFFFF);}// you must call this function once before you use any of the other functions:void init_ip_arp_udp_tcp(uint8_t *mymac,uint8_t *myip,uint8_t wwwp){        uint8_t i=0;        wwwport=wwwp;        while(i<4){                ipaddr[i]=myip[i];                i++;        }        i=0;        while(i<6){                macaddr[i]=mymac[i];                i++;        }}uint8_t eth_type_is_arp_and_my_ip(uint8_t *buf,uint16_t len){        uint8_t i=0;        //          if (len<41){                return(0);        }        if(buf[ETH_TYPE_H_P] != ETHTYPE_ARP_H_V ||            buf[ETH_TYPE_L_P] != ETHTYPE_ARP_L_V){                return(0);        }        while(i<4){                if(buf[ETH_ARP_DST_IP_P+i] != ipaddr[i]){                        return(0);                }                i++;        }        return(1);}uint8_t eth_type_is_ip_and_my_ip(uint8_t *buf,uint16_t len){        uint8_t i=0;        //eth+ip+udp header is 42        if (len<42){                return(0);        }        if(buf[ETH_TYPE_H_P]!=ETHTYPE_IP_H_V ||            buf[ETH_TYPE_L_P]!=ETHTYPE_IP_L_V){                return(0);        }        if (buf[IP_HEADER_LEN_VER_P]!=0x45){                // must be IP V4 and 20 byte header                return(0);        }        while(i<4){                if(buf[IP_DST_P+i]!=ipaddr[i]){                        return(0);                }                i++;        }        return(1);}// make a return eth header from a received eth packetvoid make_eth(uint8_t *buf){        uint8_t i=0;        //        //copy the destination mac from the source and fill my mac into src        while(i<6){                buf[ETH_DST_MAC +i]=buf[ETH_SRC_MAC +i];                buf[ETH_SRC_MAC +i]=macaddr[i];                i++;        }}void fill_ip_hdr_checksum(uint8_t *buf){        uint16_t ck;        // clear the 2 byte checksum        buf[IP_CHECKSUM_P]=0;        buf[IP_CHECKSUM_P+1]=0;        buf[IP_FLAGS_P]=0x40; // don't fragment        buf[IP_FLAGS_P+1]=0;  // fragement offset        buf[IP_TTL_P]=64; // ttl        // calculate the checksum:        ck=checksum(&buf[IP_P], IP_HEADER_LEN,0);        buf[IP_CHECKSUM_P]=ck>>8;        buf[IP_CHECKSUM_P+1]=ck& 0xff;}// make a return ip header from a received ip packetvoid make_ip(uint8_t *buf){        uint8_t i=0;        while(i<4){                buf[IP_DST_P+i]=buf[IP_SRC_P+i];                buf[IP_SRC_P+i]=ipaddr[i];                i++;        }        fill_ip_hdr_checksum(buf);}// make a return tcp header from a received tcp packet// rel_ack_num is how much we must step the seq number received from the// other side. We do not send more than 255 bytes of text (=data) in the tcp packet.// If mss=1 then mss is included in the options list//// After calling this function you can fill in the first data byte at TCP_OPTIONS_P+4// If cp_seq=0 then an initial sequence number is used (should be use in synack)// otherwise it is copied from the packet we receivedvoid make_tcphead(uint8_t *buf,uint16_t rel_ack_num,uint8_t mss,uint8_t cp_seq){        uint8_t i=0;        uint8_t tseq;        while(i<2){                buf[TCP_DST_PORT_H_P+i]=buf[TCP_SRC_PORT_H_P+i];                buf[TCP_SRC_PORT_H_P+i]=0; // clear source port                i++;        }        // set source port  (http):        buf[TCP_SRC_PORT_L_P]=wwwport;        i=4;        // sequence numbers:        // add the rel ack num to SEQACK        while(i>0){                rel_ack_num=buf[TCP_SEQ_H_P+i-1]+rel_ack_num;                tseq=buf[TCP_SEQACK_H_P+i-1];                buf[TCP_SEQACK_H_P+i-1]=0xff&rel_ack_num;                if (cp_seq){                        // copy the acknum sent to us into the sequence number                        buf[TCP_SEQ_H_P+i-1]=tseq;                }else{                        buf[TCP_SEQ_H_P+i-1]= 0; // some preset vallue                }                rel_ack_num=rel_ack_num>>8;                i--;        }        if (cp_seq==0){