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tclient.c
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tclient.c
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#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include<netdb.h>
#include <netinet/in.h>
#define FILETYPE_REQ 0xea // file-type request
#define FILETYPE_RSP 0xe9 // successful file-type response
#define FILETYPE_ERR 0xe8 // failed file-type response
#define CHECKSUM_REQ 0xca // file checksum request
#define CHECKSUM_RSP 0xc9 // successful checksum response
#define CHECKSUM_ERR 0xc8 // failed checksum response
#define DOWNLOAD_REQ 0xaa // download file request
#define DOWNLOAD_RSP 0xa9 // successful download response
#define DOWNLOAD_ERR 0xa8 // failed download response
#define UNKNOWN_FAIL 0x51 // catch-all failure response
#define MAX_PACKET_SIZE 4096 //max size of a packet frame
#define PACKET_RESERVE_SIZE 4
//tclient [hostname:]port filetype [-udp] filename
//tclient [hostname:]port checksum [-udp] [-o offset] [-l length] filename
//tclient [hostname:]port download [-udp] [-o offset] [-l length] filename [saveasfilename]
/*------------------------------------------------------------------------------*/
void writeInt32(char* buf, int val);
int readInt32(const char* buf);
int tsend(const char* src, long length);
int trecv(char* dst, long max_length);
int readData(char* buf, int length);
int readMsg(char* buf);
void TCPconnect();
void UDPconnect();
void setConnectMode();
int download(int argc,char* argv[]);
int checksum(int argc,char* argv[]);
int filetype(int argc,char* argv[]);
static char hostname[256] = "localhost";
static int port;
static char cmd[256];
int main(int argc,char* argv[]){
char* tmp;
if (argc < 4) {
fprintf(stderr, "error: lack enough parameters!");
return 1;
}
if (tmp = strrchr(argv[1], ':')) {
*tmp = '\0';
strcpy(hostname, argv[1]);
argv[1] = tmp + 1;
}
if (!(port = atoi(argv[1]))) {
fprintf(stderr, "error: illegal port!");
return 1;
}
strcpy(cmd, argv[2]);
if (strcmp("filetype", argv[2]) == 0) {
filetype(argc - 3, &argv[3]);
} else if (strcmp("checksum", argv[2]) == 0) {
checksum(argc - 3, &argv[3]);
} else if (strcmp("download", argv[2]) == 0) {
download(argc - 3, &argv[3]);
} else {
fprintf(stderr, "error: illegal command!");
return 1;
}
return 0;
}
/*------------------------------------------------------------------------------*/
static int udp = 0;
static char filename[256];
static int offset = 0;
static int length = -1;
static char saveasfilename[256];
static int sock_fd;
static struct sockaddr_in server_addr;
static int packet_seq = 123;
void writeInt32(char* buf, int val) {
memcpy(buf, (const char*) &val, 4);
}
int readInt32(const char* buf) {
int val;
memcpy(&val, buf, 4);
return val;
}
int tsend(const char* src, long length) {
char packet[MAX_PACKET_SIZE];
if (udp) {
writeInt32(packet, htonl(packet_seq++));
writeInt32(packet + 4, htonl(0));
memcpy(packet + 4 + PACKET_RESERVE_SIZE, src, length);
return sendto(sock_fd, packet, length + 4 + PACKET_RESERVE_SIZE, 0, (struct sockaddr*) &server_addr, sizeof(server_addr));
} else {
return send(sock_fd, src, length, 0);
}
}
int trecv(char* dst, long max_length) {
char packet[MAX_PACKET_SIZE];
struct sockaddr_in peer;
socklen_t addrlen = sizeof peer;
int ret;
if (udp) {
ret = recvfrom(sock_fd, packet, MAX_PACKET_SIZE, 0, (struct sockaddr*) &peer, &addrlen);
if (addrlen != sizeof(peer) || memcmp((const void*) &peer, (const void*) &server_addr, addrlen) != 0) {
return -1;
}
if (ret < 4 + PACKET_RESERVE_SIZE) {
return -1;
}
//ACK
sendto(sock_fd, packet, 4 + PACKET_RESERVE_SIZE, 0, (struct sockaddr*) &server_addr, sizeof(server_addr));
ret -= 4 + PACKET_RESERVE_SIZE;
memcpy(dst, packet + 4 + PACKET_RESERVE_SIZE, ret);
return ret;
} else {
return recv(sock_fd, dst, max_length, 0);
}
}
int readData(char* buf, int length) {
int n, read;
while (length > 0) {
n = trecv(buf, length);
if (n < 1) {
return -1;
}
length -= n;
buf += n;
}
return 0;
}
//read a complete messge
int readMsg(char* buf){
int n, read, len;
if (udp) {
return trecv(buf, MAX_PACKET_SIZE) < 0;
} else {
if (readData(buf, 5)) {
return -1;
}
len = ntohl(readInt32(buf + 1));
return readData(buf + 5, len);
}
}
void UDPconnect(){
struct hostent* host;
sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
bzero(&server_addr, sizeof(struct sockaddr_in));
if ((host = gethostbyname(hostname)) == NULL) {
fprintf(stderr, "fail to get host ip !\n");
exit(1);
}
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = *(in_addr_t*) *host->h_addr_list;
server_addr.sin_port = htons(port);
}
void TCPconnect(){
struct hostent *host;
sock_fd = socket(AF_INET, SOCK_STREAM, 0);
bzero(&server_addr, sizeof(struct sockaddr_in));
if ((host = gethostbyname(hostname)) == NULL) {
fprintf(stderr,"fail to get host ip !\n");
exit(1);
}
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = *(in_addr_t*) *host->h_addr_list;
server_addr.sin_port = htons(port);
if(connect(sock_fd, (struct sockaddr*) (&server_addr), sizeof(struct sockaddr)) == -1) {
fprintf(stderr, "fail to connect server!\n");
exit(1);
}
}
void setConnectMode() {
if(udp) {
UDPconnect();
} else {
TCPconnect();
}
}
int filetype(int argc, char* argv[]) {
int ret;
int len;
int k;
char buff[MAX_PACKET_SIZE] = {0};
if(argc > 2) {
fprintf(stderr, "error: too much parameters\n");
return 1;
}
if(argc > 1) {
if(strcmp("-udp", argv[0]) != 0) {
fprintf(stderr, "error: unknown parameter\n");
return 1;
}
udp = 1;
++argv;
}
strcpy(filename, argv[0]);
setConnectMode();
buff[0] = (char) FILETYPE_REQ;
writeInt32(buff + 1, htonl(strlen(filename)));
strcpy(buff + 5, filename);
ret = tsend(buff, 5 + strlen(filename));
if (readMsg(buff)) {
fprintf(stderr, "fail to get response from server!\n");
} else {
if ((0xff & buff[0]) == FILETYPE_RSP) {
len = ntohl(readInt32(buff + 1));
buff[5 + len] = '\0';
for (k = 0; k < len; k++) {
if((0xff & buff[5 + k]) > 0x7f) {break;}
}
if (k < len) {
fprintf(stdout, "Invalid characters detected in a FILETYPE_RSP message.\n");
} else {
fprintf(stdout, "%s\n", &buff[5]);
}
} else if ((0xff & buff[0]) == FILETYPE_ERR) {
fprintf(stdout, "FILETYPE_ERR received from the server\n");
}
}
close(sock_fd);
return 0;
}
int checksum(int argc, char*argv[]) {
char buff[MAX_PACKET_SIZE] = {0};
int k, ret, len;
if(argc > 6) {
fprintf(stderr, "error: too much parameters\n");
return 1;
}
for (k = 0; k < argc; ++k) {
if(strcmp("-udp", argv[k]) == 0) {
udp = 1;
} else if (strcmp("-o", argv[k]) == 0) {
if (k + 1 == argc) {
fprintf(stderr, "error: need offset\n");
return 1;
}
if ((offset = atoi(argv[++k])) < 0) {
fprintf(stderr, "error: illegal offset!\n");
return 1;
}
} else if (strcmp("-l", argv[k]) == 0) {
if (argc == k + 1) {
fprintf(stderr, "error: need length\n");
return 1;
}
if (!(length = atoi(argv[++k]))) {
fprintf(stderr, "error: illegal length!\n");
return 1;
}
} else {
strcpy(filename, argv[k]);
}
}
setConnectMode();
buff[0] = (char)CHECKSUM_REQ;
writeInt32(buff + 1, htonl(8 + strlen(filename)));
writeInt32(buff + 5, htonl(offset));
writeInt32(buff + 9, htonl(length));
strcpy(buff + 13, filename);
ret = tsend(buff, 13 + strlen(filename));
if(readMsg(buff)) {
fprintf(stderr, "fail to get response from server!\n");
} else {
if ((0xff & buff[0]) == CHECKSUM_RSP) {
len = ntohl(readInt32(buff + 1));
if (len != 16) {
fprintf(stdout,"Invalid DataLength detected in a CHECKSUM_RSP message.\n");
} else {
for (k = 0; k < 16; k++) {
fprintf(stdout, "%02x", (0xff & buff[5 + k]));
}
fprintf(stdout, "\n");
}
} else if ((0xff & buff[0]) == CHECKSUM_ERR) {
fprintf(stdout, "CHECKSUM_ERR received from the server\n");
}
}
close(sock_fd);
return 0;
}
int download(int argc, char* argv[]) {
char buff[MAX_PACKET_SIZE] = {0};
int k, ret, len;
FILE* pf;
if (argc > 7) {
fprintf(stderr, "error: too much parameters\n");
return 1;
}
for (k = 0; k < argc; ++k) {
if (strcmp("-udp", argv[k]) == 0) {
udp = 1;
} else if (strcmp("-o", argv[k]) == 0) {
if (argc == k + 1) {
fprintf(stderr, "error: need offset\n");
return 1;
}
if (!(offset = atoi(argv[++k]))) {
fprintf(stderr, "error: illegal offset!\n");
return 1;
}
} else if (strcmp("-l", argv[k]) == 0) {
if (argc == k + 1) {
fprintf(stderr, "error: need length\n");
return 1;
}
if (!(length = atoi(argv[++k]))) {
fprintf(stderr, "error: illegal length!\n");
return 1;
}
} else if (!filename[0]) {
strcpy(filename, argv[k]);
} else {
strcpy(saveasfilename, argv[k]);
}
}
setConnectMode();
buff[0] = (char) DOWNLOAD_REQ;
writeInt32(buff + 1, htonl(8 + strlen(filename)));
writeInt32(buff + 5, htonl(offset));
writeInt32(buff + 9, htonl(length));
strcpy(buff + 13, filename);
ret = tsend(buff, 13 + strlen(filename));
//get head of reponse
if (readData(buff, 5)) {
//fail to get the head
fprintf(stderr, "fail to get response from server!\n");
} else {
if((0xff & buff[0]) == DOWNLOAD_RSP) {//successful reponse
len = ntohl(readInt32(buff + 1));//data length
if (NULL == (pf = fopen(saveasfilename, "wb"))) {
fprintf(stderr, "fail to open save file %s!\n", saveasfilename);
} else {
//download file
while (len > 0) {
k = len > sizeof(buff) ? sizeof(buff) : len;
if ((k = trecv(buff, sizeof(buff))) < 1) {
fprintf(stderr, "fail to receive data from server!\n");
break;
} else {
fwrite(buff, 1, k, pf);
}
len -= k;
}
fclose(pf);
fprintf(stdout, "...Downloaded data have been successfully written into '%s'\n", saveasfilename);
}
} else if ((0xff & buff[0]) == DOWNLOAD_ERR) {
fprintf(stdout, "DOWNLOAD_ERR received from the server\n");
}
}
close(sock_fd);
return 0;
}