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463 lines
14 KiB
463 lines
14 KiB
/* tftp.c - TFTP client.
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*
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* Copyright 2012 Madhur Verma <mad.flexi@gmail.com>
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* Copyright 2015 Sameer Prakash Pradhan <sameer.p.pradhan@gmail.com>
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*
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* No Standard.
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USE_TFTP(NEWTOY(tftp, "<1b#<8>65464r:l:g|p|[!gp]", TOYFLAG_USR|TOYFLAG_BIN))
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config TFTP
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bool "tftp"
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default n
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help
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usage: tftp [OPTIONS] HOST [PORT]
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Transfer file from/to tftp server.
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-l FILE Local FILE
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-r FILE Remote FILE
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-g Get file
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-p Put file
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-b SIZE Transfer blocks of SIZE octets(8 <= SIZE <= 65464)
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*/
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#define FOR_tftp
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#include "toys.h"
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GLOBALS(
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char *local_file;
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char *remote_file;
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long block_size;
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struct sockaddr_storage inaddr;
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int af;
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)
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#define TFTP_BLKSIZE 512
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#define TFTP_RETRIES 3
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#define TFTP_DATAHEADERSIZE 4
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#define TFTP_MAXPACKETSIZE (TFTP_DATAHEADERSIZE + TFTP_BLKSIZE)
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#define TFTP_PACKETSIZE TFTP_MAXPACKETSIZE
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#define TFTP_DATASIZE (TFTP_PACKETSIZE-TFTP_DATAHEADERSIZE)
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#define TFTP_IOBUFSIZE (TFTP_PACKETSIZE+8)
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#define TFTP_OP_RRQ 1 /* Read Request RFC 1350, RFC 2090 */
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#define TFTP_OP_WRQ 2 /* Write Request RFC 1350 */
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#define TFTP_OP_DATA 3 /* Data chunk RFC 1350 */
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#define TFTP_OP_ACK 4 /* Acknowledgement RFC 1350 */
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#define TFTP_OP_ERR 5 /* Error Message RFC 1350 */
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#define TFTP_OP_OACK 6 /* Option acknowledgment RFC 2347 */
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#define TFTP_ER_ILLEGALOP 4 /* Illegal TFTP operation */
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#define TFTP_ER_UNKID 5 /* Unknown transfer ID */
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#define TFTP_ES_NOSUCHFILE "File not found"
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#define TFTP_ES_ACCESS "Access violation"
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#define TFTP_ES_FULL "Disk full or allocation exceeded"
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#define TFTP_ES_ILLEGALOP "Illegal TFTP operation"
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#define TFTP_ES_UNKID "Unknown transfer ID"
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#define TFTP_ES_EXISTS "File already exists"
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#define TFTP_ES_UNKUSER "No such user"
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#define TFTP_ES_NEGOTIATE "Terminate transfer due to option negotiation"
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// Initializes SERVER with ADDR and returns socket.
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static int init_tftp(struct sockaddr_storage *server)
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{
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struct timeval to = { .tv_sec = 10, //Time out
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.tv_usec = 0 };
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const int set = 1;
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int port = 69, sd = xsocket(TT.af, SOCK_DGRAM, IPPROTO_UDP);
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xsetsockopt(sd, SOL_SOCKET, SO_RCVTIMEO, (void *)&to, sizeof(struct timeval));
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xsetsockopt(sd, SOL_SOCKET, SO_REUSEADDR, (void *)&set, sizeof(set));
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if(toys.optc == 2) port = atolx_range(toys.optargs[1], 1, 65535);
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memset(server, 0, sizeof(struct sockaddr_storage));
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if (TT.af == AF_INET6) {
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((struct sockaddr_in6 *)server)->sin6_family = AF_INET6;
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((struct sockaddr_in6 *)server)->sin6_addr =
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((struct sockaddr_in6 *)&TT.inaddr)->sin6_addr;
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((struct sockaddr_in6 *)server)->sin6_port = htons(port);
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}
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else {
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((struct sockaddr_in *)server)->sin_family = AF_INET;
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((struct sockaddr_in *)server)->sin_addr.s_addr =
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((struct sockaddr_in *)&TT.inaddr)->sin_addr.s_addr;
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((struct sockaddr_in *)server)->sin_port = htons(port);
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}
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return sd;
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}
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/*
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* Makes a request packet in BUFFER with OPCODE and file PATH of MODE
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* and returns length of packet.
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*/
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static int mkpkt_request(uint8_t *buffer, int opcode, char *path, int mode)
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{
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buffer[0] = opcode >> 8;
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buffer[1] = opcode & 0xff;
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if(strlen(path) > TFTP_BLKSIZE) error_exit("path too long");
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return sprintf((char*) &buffer[2], "%s%c%s", path, 0,
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(mode ? "octet" : "netascii")) + 3;
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}
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/*
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* Makes an acknowledgement packet in BUFFER of BLOCNO
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* and returns packet length.
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*/
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static int mkpkt_ack(uint8_t *buffer, uint16_t blockno)
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{
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buffer[0] = TFTP_OP_ACK >> 8;
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buffer[1] = TFTP_OP_ACK & 0xff;
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buffer[2] = blockno >> 8;
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buffer[3] = blockno & 0xff;
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return 4;
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}
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/*
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* Makes an error packet in BUFFER with ERRORCODE and ERRORMSG.
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* and returns packet length.
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*/
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static int mkpkt_err(uint8_t *buffer, uint16_t errorcode, char *errormsg)
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{
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buffer[0] = TFTP_OP_ERR >> 8;
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buffer[1] = TFTP_OP_ERR & 0xff;
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buffer[2] = errorcode >> 8;
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buffer[3] = errorcode & 0xff;
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strcpy((char*) &buffer[4], errormsg);
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return strlen(errormsg) + 5;
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}
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/*
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* Recieves data from server in BUFF with socket SD and updates FROM
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* and returns read length.
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*/
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static int read_server(int sd, void *buf, int len,
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struct sockaddr_storage *from)
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{
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socklen_t alen;
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ssize_t nb;
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for (;;) {
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memset(buf, 0, len);
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alen = sizeof(struct sockaddr_storage);
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nb = recvfrom(sd, buf, len, 0, (struct sockaddr *) from, &alen);
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if (nb < 0) {
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if (errno == EAGAIN) {
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perror_msg("server read timed out");
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return nb;
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}else if (errno != EINTR) {
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perror_msg("server read failed");
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return nb;
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}
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}else return nb;
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}
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return nb;
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}
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/*
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* sends data to server TO from BUFF of length LEN through socket SD
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* and returns successfully send bytes number.
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*/
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static ssize_t write_server(int sd, void *buf, size_t len,
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struct sockaddr_storage *to)
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{
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ssize_t nb;
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for (;;) {
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nb = sendto(sd, buf, len, 0, (struct sockaddr *)to,
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sizeof(struct sockaddr_storage));
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if (nb < 0) {
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if (errno != EINTR) {
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perror_msg("server write failed");
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return nb;
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}
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} else return nb;
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}
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return nb;
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}
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// checks packet for data and updates block no
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static inline int check_data( uint8_t *packet, uint16_t *opcode,
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uint16_t *blockno)
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{
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*opcode = (uint16_t) packet[0] << 8 | (uint16_t) packet[1];
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if (*opcode == TFTP_OP_DATA) {
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*blockno = (uint16_t) packet[2] << 8 | (uint16_t) packet[3];
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return 0;
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}
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return -1;
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}
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// Makes data packet through FD from file OFFSET in buffer PACKET of BLOCKNO
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static int mkpkt_data(int fd, off_t offset, uint8_t *packet, uint16_t blockno)
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{
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off_t tmp;
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int nbytesread;
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packet[0] = TFTP_OP_DATA >> 8;
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packet[1] = TFTP_OP_DATA & 0xff;
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packet[2] = blockno >> 8;
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packet[3] = blockno & 0xff;
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tmp = lseek(fd, offset, SEEK_SET);
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if (tmp == (off_t) -1) {
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perror_msg("lseek failed");
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return -1;
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}
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nbytesread = readall(fd, &packet[TFTP_DATAHEADERSIZE], TFTP_DATASIZE);
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if (nbytesread < 0) return -1;
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return nbytesread + TFTP_DATAHEADERSIZE;
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}
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// Receives ACK responses from server and updates blockno
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static int read_ack(int sd, uint8_t *packet, struct sockaddr_storage *server,
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uint16_t *port, uint16_t *blockno)
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{
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struct sockaddr_storage from;
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int nbytes;
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uint16_t opcode, rblockno;
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int packetlen, retry;
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for (retry = 0; retry < TFTP_RETRIES; retry++) {
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for (;;) {
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nbytes = read_server(sd, packet, TFTP_IOBUFSIZE, &from);
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if (nbytes < 4) { // Ack headersize = 4
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if (nbytes == 0) error_msg("Connection lost.");
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else if (nbytes > 0) error_msg("Short packet: %d bytes", nbytes);
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else error_msg("Server read ACK failure.");
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break;
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} else {
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if (!*port) {
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*port = ((struct sockaddr_in *)&from)->sin_port;
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((struct sockaddr_in *)server)->sin_port =
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((struct sockaddr_in *)&from)->sin_port;
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}
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if (((struct sockaddr_in *)server)->sin_addr.s_addr !=
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((struct sockaddr_in *)&from)->sin_addr.s_addr) {
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error_msg("Invalid address in DATA.");
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continue;
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}
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if (*port != ((struct sockaddr_in *)server)->sin_port) {
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error_msg("Invalid port in DATA.");
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packetlen = mkpkt_err(packet, TFTP_ER_UNKID, TFTP_ES_UNKID);
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(void) write_server(sd, packet, packetlen, server);
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continue;
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}
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opcode = (uint16_t) packet[0] << 8 | (uint16_t) packet[1];
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rblockno = (uint16_t) packet[2] << 8 | (uint16_t) packet[3];
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if (opcode != TFTP_OP_ACK) {
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error_msg("Bad opcode.");
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if (opcode > 5) {
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packetlen = mkpkt_err(packet, TFTP_ER_ILLEGALOP, TFTP_ES_ILLEGALOP);
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(void) write_server(sd, packet, packetlen, server);
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}
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break;
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}
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if (blockno) *blockno = rblockno;
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return 0;
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}
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}
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}
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error_msg("Timeout, Waiting for ACK.");
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return -1;
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}
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// receives file from server.
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static int file_get(void)
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{
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struct sockaddr_storage server, from;
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uint8_t *packet;
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uint16_t blockno = 0, opcode, rblockno = 0;
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int len, sd, fd, retry, nbytesrecvd = 0, ndatabytes, ret, result = -1;
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sd = init_tftp(&server);
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packet = (uint8_t*) xzalloc(TFTP_IOBUFSIZE);
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fd = xcreate(TT.local_file, O_WRONLY | O_CREAT | O_TRUNC, 0666);
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len = mkpkt_request(packet, TFTP_OP_RRQ, TT.remote_file, 1);
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ret = write_server(sd, packet, len, &server);
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if (ret != len){
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unlink(TT.local_file);
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goto errout_with_sd;
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}
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if (TT.af == AF_INET6) ((struct sockaddr_in6 *)&server)->sin6_port = 0;
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else ((struct sockaddr_in *)&server)->sin_port = 0;
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do {
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blockno++;
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for (retry = 0 ; retry < TFTP_RETRIES; retry++) {
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nbytesrecvd = read_server(sd, packet, TFTP_IOBUFSIZE, &from);
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if (nbytesrecvd > 0) {
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if ( ((TT.af == AF_INET) &&
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memcmp(&((struct sockaddr_in *)&server)->sin_addr,
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&((struct sockaddr_in *)&from)->sin_addr,
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sizeof(struct in_addr))) ||
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((TT.af == AF_INET6) &&
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memcmp(&((struct sockaddr_in6 *)&server)->sin6_addr,
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&((struct sockaddr_in6 *)&from)->sin6_addr,
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sizeof(struct in6_addr)))) {
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error_msg("Invalid address in DATA.");
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retry--;
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continue;
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}
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if ( ((TT.af == AF_INET) && ((struct sockaddr_in *)&server)->sin_port
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&& (((struct sockaddr_in *)&server)->sin_port !=
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((struct sockaddr_in *)&from)->sin_port)) ||
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((TT.af == AF_INET6) && ((struct sockaddr_in6 *)&server)->sin6_port
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&& (((struct sockaddr_in6 *)&server)->sin6_port !=
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((struct sockaddr_in6 *)&from)->sin6_port))) {
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error_msg("Invalid port in DATA.");
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len = mkpkt_err(packet, TFTP_ER_UNKID, TFTP_ES_UNKID);
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ret = write_server(sd, packet, len, &from);
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retry--;
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continue;
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}
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if (nbytesrecvd < TFTP_DATAHEADERSIZE) {
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error_msg("Tiny data packet ignored.");
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continue;
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}
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if (check_data(packet, &opcode, &rblockno) != 0
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|| blockno != rblockno) {
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if (opcode == TFTP_OP_ERR) {
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char *message = "DATA Check failure.";
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char *arr[] = {TFTP_ES_NOSUCHFILE, TFTP_ES_ACCESS,
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TFTP_ES_FULL, TFTP_ES_ILLEGALOP,
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TFTP_ES_UNKID, TFTP_ES_EXISTS,
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TFTP_ES_UNKUSER, TFTP_ES_NEGOTIATE};
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if (rblockno && (rblockno < 9)) message = arr[rblockno - 1];
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error_msg_raw(message);
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}
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else if (blockno == 1 && opcode == TFTP_OP_OACK) {
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len = mkpkt_ack(packet, 0);
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ret = write_server(sd, packet, len, &from);
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if (ret != len){
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unlink(TT.local_file);
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goto errout_with_sd;
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}
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}
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else if (opcode > 5) {
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len = mkpkt_err(packet, TFTP_ER_ILLEGALOP, TFTP_ES_ILLEGALOP);
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ret = write_server(sd, packet, len, &from);
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}
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continue;
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}
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if ((TT.af == AF_INET6) && !((struct sockaddr_in6 *)&server)->sin6_port)
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((struct sockaddr_in6 *)&server)->sin6_port =
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((struct sockaddr_in6 *)&from)->sin6_port;
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else if ((TT.af == AF_INET) && !((struct sockaddr_in *)&server)->sin_port)
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((struct sockaddr_in *)&server)->sin_port =
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((struct sockaddr_in *)&from)->sin_port;
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break;
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}
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}
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if (retry == TFTP_RETRIES) {
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error_msg("Retry limit exceeded.");
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unlink(TT.local_file);
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goto errout_with_sd;
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}
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ndatabytes = nbytesrecvd - TFTP_DATAHEADERSIZE;
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if (writeall(fd, packet + TFTP_DATAHEADERSIZE, ndatabytes) < 0){
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unlink(TT.local_file);
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goto errout_with_sd;
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}
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len = mkpkt_ack(packet, blockno);
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ret = write_server(sd, packet, len, &server);
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if (ret != len){
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unlink(TT.local_file);
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goto errout_with_sd;
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}
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} while (ndatabytes >= TFTP_DATASIZE);
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result = 0;
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errout_with_sd: xclose(sd);
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free(packet);
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return result;
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}
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// Sends file to server.
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int file_put(void)
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{
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struct sockaddr_storage server;
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uint8_t *packet;
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off_t offset = 0;
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uint16_t blockno = 1, rblockno, port = 0;
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int packetlen, sd, fd, retry = 0, ret, result = -1;
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sd = init_tftp(&server);
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packet = (uint8_t*)xzalloc(TFTP_IOBUFSIZE);
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fd = xopenro(TT.local_file);
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for (;;) { //first loop for request send and confirmation from server.
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packetlen = mkpkt_request(packet, TFTP_OP_WRQ, TT.remote_file, 1);
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ret = write_server(sd, packet, packetlen, &server);
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if (ret != packetlen) goto errout_with_sd;
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if (read_ack(sd, packet, &server, &port, NULL) == 0) break;
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if (++retry > TFTP_RETRIES) {
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error_msg("Retry count exceeded.");
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goto errout_with_sd;
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}
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}
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for (;;) { // loop for data sending and receving ack from server.
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packetlen = mkpkt_data(fd, offset, packet, blockno);
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if (packetlen < 0) goto errout_with_sd;
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ret = write_server(sd, packet, packetlen, &server);
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if (ret != packetlen) goto errout_with_sd;
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if (read_ack(sd, packet, &server, &port, &rblockno) == 0) {
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if (rblockno == blockno) {
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if (packetlen < TFTP_PACKETSIZE) break;
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blockno++;
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offset += TFTP_DATASIZE;
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retry = 0;
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continue;
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}
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}
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if (++retry > TFTP_RETRIES) {
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error_msg("Retry count exceeded.");
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goto errout_with_sd;
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}
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}
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result = 0;
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errout_with_sd: close(sd);
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free(packet);
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return result;
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}
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void tftp_main(void)
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{
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struct addrinfo *info, rp, *res=0;
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int ret;
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if (FLAG(r)) {
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if (!FLAG(l)) {
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char *slash = strrchr(TT.remote_file, '/');
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TT.local_file = (slash) ? slash + 1 : TT.remote_file;
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}
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} else if (FLAG(l)) TT.remote_file = TT.local_file;
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else error_exit("Please provide some files.");
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memset(&rp, 0, sizeof(rp));
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rp.ai_family = AF_UNSPEC;
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rp.ai_socktype = SOCK_STREAM;
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ret = getaddrinfo(toys.optargs[0], toys.optargs[1], &rp, &info);
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if (!ret) {
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for (res = info; res; res = res->ai_next)
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if ( (res->ai_family == AF_INET) || (res->ai_family == AF_INET6)) break;
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}
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if (!res)
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error_exit("bad address '%s' : %s", toys.optargs[0], gai_strerror(ret));
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TT.af = info->ai_family;
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memcpy((void *)&TT.inaddr, info->ai_addr, info->ai_addrlen);
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freeaddrinfo(info);
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if (FLAG(g)) file_get();
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if (FLAG(p)) file_put();
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}
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