TCP.rar_TCP协议实验_tcp_tcp 实验_tcp协议_visual c

#include "sysinclude.h" extern void tcp_DiscardPkt(char* pBuffer, int type); extern void tcp_sendReport(int type); extern void tcp_sendIpPkt(unsigned char* pData, UINT16 len, unsigned int srcAddr, unsigned int dstAddr, UINT8 ttl); extern int waitIpPacket(char *pBuffer, int timeout); extern unsigned int getIpv4Address(); extern unsigned int getServerIpv4Address(); #define INPUT 0 #define OUTPUT 1 #define NOT_READY 0 #define READY 1 #define DATA_NOT_ACKED 0 #define DATA_ACKED 1 #define NOT_USED 0 #define USED 1 #define MAX_TCP_CONNECTIONS 5 #define INPUT_SEG 0 #define OUTPUT_SEG 1 typedef int STATE; int gLocalPort = 2007; int gRemotePort = 2006; int gSeqNum = 1234; int gAckNum = 0; enum TCP_STATES { CLOSED, SYN_SENT, ESTABLISHED, FIN_WAIT1, FIN_WAIT2, TIME_WAIT, }; struct MyTcpSeg { unsigned short src_port; unsigned short dst_port; unsigned int seq_num; unsigned int ack_num; unsigned char hdr_len; unsigned char flags; unsigned short window_size; unsigned short checksum; unsigned short urg_ptr; unsigned char data[2048]; unsigned short len; }; struct MyTCB { STATE current_state; unsigned int local_ip; unsigned short local_port; unsigned int remote_ip; unsigned short remote_port; unsigned int seq; unsigned int ack; unsigned char flags; int iotype; int is_used; int data_ack; unsigned char data[2048]; unsigned short data_len; }; struct MyTCB gTCB[MAX_TCP_CONNECTIONS]; int initialized = NOT_READY; int convert_tcp_hdr_ntoh(struct MyTcpSeg* pTcpSeg) { if( pTcpSeg == NULL ) { return -1; } pTcpSeg->src_port = ntohs(pTcpSeg->src_port); pTcpSeg->dst_port = ntohs(pTcpSeg->dst_port); pTcpSeg->seq_num = ntohl(pTcpSeg->seq_num); pTcpSeg->ack_num = ntohl(pTcpSeg->ack_num); pTcpSeg->window_size = ntohs(pTcpSeg->window_size); pTcpSeg->checksum = ntohs(pTcpSeg->checksum); pTcpSeg->urg_ptr = ntohs(pTcpSeg->urg_ptr); return 0; } int convert_tcp_hdr_hton(struct MyTcpSeg* pTcpSeg) { if( pTcpSeg == NULL ) { return -1; } pTcpSeg->src_port = htons(pTcpSeg->src_port); pTcpSeg->dst_port = htons(pTcpSeg->dst_port); pTcpSeg->seq_num = htonl(pTcpSeg->seq_num); pTcpSeg->ack_num = htonl(pTcpSeg->ack_num); pTcpSeg->window_size = htons(pTcpSeg->window_size); pTcpSeg->checksum = htons(pTcpSeg->checksum); pTcpSeg->urg_ptr = htons(pTcpSeg->urg_ptr); return 0; } unsigned short tcp_calc_checksum(struct MyTCB* pTcb, struct MyTcpSeg* pTcpSeg) { int i = 0; int len = 0; unsigned int sum = 0; unsigned short* p = (unsigned short*)pTcpSeg; if( pTcb == NULL || pTcpSeg == NULL ) { return 0; } for( i=0; i<10; i++) { sum += p[i]; } sum = sum - p[8] - p[6] + ntohs(p[6]); //printf("1...sum =%.2x\n", sum ); if( (len = pTcpSeg->len) > 20 ) { if( len % 2 == 1 ) { pTcpSeg->data[len - 20] = 0; len++; } for( i=10; i<len/2; i++ ) { sum += ntohs(p[i]); } } //printf("2...sum =%.2x\n", sum ); sum = sum + (unsigned short)(pTcb->local_ip>>16) + (unsigned short)(pTcb->local_ip&0xffff) + (unsigned short)(pTcb->remote_ip>>16) + (unsigned short)(pTcb->remote_ip&0xffff); sum = sum + 6 + pTcpSeg->len; sum = ( sum & 0xFFFF ) + ( sum >> 16 ); sum = ( sum & 0xFFFF ) + ( sum >> 16 ); return (unsigned short)(~sum); } int get_socket(unsigned short local_port, unsigned short remote_port) { int i = 1; int sockfd = -1; for( i=1; i<MAX_TCP_CONNECTIONS; i++ ) { if( gTCB[i].is_used == USED && gTCB[i].local_port == local_port && gTCB[i].remote_port == remote_port ) { sockfd = i; break; } } return sockfd; } int tcp_init(int sockfd) { if( gTCB[sockfd].is_used == USED ) { return -1; } gTCB[sockfd].current_state = CLOSED; gTCB[sockfd].local_ip = getIpv4Address(); gTCB[sockfd].local_port = gLocalPort + sockfd - 1; //gTCB[sockfd].remote_ip = ntohl(getServerIpv4Address()); //gTCB[sockfd].remote_port = gDstPort; gTCB[sockfd].seq = gSeqNum; gTCB[sockfd].ack = gAckNum; gTCB[sockfd].is_used = USED; gTCB[sockfd].data_ack = DATA_ACKED; return 0; } int tcp_construct_segment(struct MyTcpSeg* pTcpSeg, struct MyTCB* pTcb, unsigned short datalen, unsigned char* pData) { pTcpSeg->src_port = pTcb->local_port; pTcpSeg->dst_port = pTcb->remote_port; pTcpSeg->seq_num = pTcb->seq; pTcpSeg->ack_num = pTcb->ack; pTcpSeg->hdr_len = (unsigned char)(0x50); pTcpSeg->flags = pTcb->flags; pTcpSeg->window_size = 1024; pTcpSeg->urg_ptr = 0; if( datalen > 0 && pData != NULL ) { memcpy(pTcpSeg->data, pData, datalen); } pTcpSeg->len = 20 + datalen; return 0; } int tcp_kick(struct MyTCB* pTcb, struct MyTcpSeg* pTcpSeg) { pTcpSeg->checksum = tcp_calc_checksum(pTcb, pTcpSeg); convert_tcp_hdr_hton(pTcpSeg); tcp_sendIpPkt((unsigned char*)pTcpSeg, pTcpSeg->len, pTcb->local_ip, pTcb->remote_ip, 255); //memcpy(&(pTcb->last_seg), pTcpSeg, pTcpSeg->len); if( (pTcb->flags & 0x0f) == 0x00 ) { //data pTcb->seq += pTcpSeg->len - 20; } else if( (pTcb->flags & 0x0f) == 0x02 ) { //syn pTcb->seq++; } else if( (pTcb->flags & 0x0f) == 0x01 ) { //fin pTcb->seq++; } else if( (pTcb->flags & 0x3f) == 0x10 ) { //ack } return 0; } int tcp_closed(struct MyTCB* pTcb, struct MyTcpSeg* pTcpSeg) { if( pTcb == NULL || pTcpSeg == NULL ) { return -1; } if( pTcb->iotype != OUTPUT ) { //to do: discard packet return -1; } pTcb->current_state = SYN_SENT; pTcb->seq = pTcpSeg->seq_num ; tcp_kick( pTcb, pTcpSeg ); return 0; } int tcp_syn_sent(struct MyTCB* pTcb, struct MyTcpSeg* pTcpSeg) { struct MyTcpSeg my_seg; if( pTcb == NULL || pTcpSeg == NULL ) { return -1; } if( pTcb->iotype != INPUT ) { return -1; } if( (pTcpSeg->flags & 0x3f) != 0x12 ) { //to do: discard packet return -1; } pTcb->ack = pTcpSeg->seq_num + 1; pTcb->flags = 0x10; tcp_construct_segment( &my_seg, pTcb, 0, NULL ); tcp_kick( pTcb, &my_seg ); pTcb->current_state = ESTABLISHED; return 0; } int tcp_established(struct MyTCB* pTcb, struct MyTcpSeg* pTcpSeg) { struct MyTcpSeg my_seg; if( pTcb == NULL || pTcpSeg == NULL ) { return -1; } if( pTcb->iotype == INPUT ) { if( pTcpSeg->seq_num != pTcb->ack ) { tcp_DiscardPkt((char*)pTcpSeg, STUD_TCP_TEST_SEQNO_ERROR); //to do: discard packet return -1; } if( (pTcpSeg->flags & 0x3f) == 0x10 ) { //get packet and ack it memcpy(pTcb->data, pTcpSeg->data, pTcpSeg->len - 20); pTcb->data_len = pTcpSeg->len - 20; if( pTcb->data_len == 0 ) { //pTcb->ack = pTcpSeg->seq_num + 1; //pTcb->ack++; } else { pTcb->ack += pTcb->data_len; pTcb->flags = 0x10; tcp_construct_segment(&my_seg, pTcb, 0, NULL); tcp_kick(pTcb, &my_seg); } } } else { if( (pTcpSeg->flags & 0x0F) == 0x01 ) { pTcb->current_state = FIN_WAIT1; } tcp_kick( pTcb, pTcpSeg ); } return 0; } int tcp_finwait_1(struct MyTCB* pTcb, struct MyTcpSeg* pTcpSeg) { if( pTcb == NULL || pTcpSeg == NULL ) { return -1; } if( pTcb->iotype != INPUT ) { return -1; } if( pTcpSeg->seq_num != pTcb->ack ) { tcp_DiscardPkt((char*)pTcpSeg, STUD_TCP_TEST_SEQNO_ERROR); return -1; } if( (pTcpSeg->flags & 0x3f) == 0x10 && pTcpSeg->ack_num == pTcb->seq ) { pTcb->current_state = FIN_WAIT2; //pTcb->ack++; } return 0; } int tcp_finwait_2(struct MyTCB* pTcb, struct MyTcpSeg* pTcpSeg) { struct MyTcpSeg my_seg; if( pTcb == NULL || pTcpSeg == NULL ) { return -1; } if( pTcb->iotype != INPUT ) { return -1; } if( pTcpSeg->seq_num != pTcb->ack ) { tcp_DiscardPkt((char*)pTcpSeg, STUD_TCP_TEST_SEQNO_ERROR); return -1; } if( (pTcpSeg->flags & 0