int tftpget(const char *remote, const char *local, in_addr_t addr, bool binary)
{
struct sockaddr_in server; /* The address of the TFTP server */
struct sockaddr_in from; /* The address the last UDP message recv'd from */
uint8_t *packet; /* Allocated memory to hold one packet */
uint16_t blockno = 0; /* The current transfer block number */
uint16_t opcode; /* Received opcode */
uint16_t rblockno; /* Received block number */
int len; /* Generic length */
int sd; /* Socket descriptor for socket I/O */
int fd; /* File descriptor for file I/O */
int retry; /* Retry counter */
int nbytesrecvd = 0; /* The number of bytes received in the packet */
int ndatabytes; /* The number of data bytes received */
int result = ERROR; /* Assume failure */
int ret; /* Generic return status */
/* Allocate the buffer to used for socket/disk I/O */
packet = (uint8_t*)zalloc(TFTP_IOBUFSIZE);
if (!packet)
{
ndbg("packet memory allocation failure\n");
set_errno(ENOMEM);
goto errout;
}
/* Open the file for writing */
fd = open(local, O_WRONLY|O_CREAT|O_TRUNC, 0666);
if (fd < 0)
{
ndbg("open failed: %d\n", errno);
goto errout_with_packet;
}
/* Initialize a UDP socket and setup the server addresss */
sd = tftp_sockinit(&server, addr);
if (sd < 0)
{
goto errout_with_fd;
}
/* Then enter the transfer loop. Loop until the entire file has
* been received or until an error occurs.
*/
do
{
/* Increment the TFTP block number for the next transfer */
blockno++;
/* Send the next block if the file within a loop. We will
* retry up to TFTP_RETRIES times before giving up on the
* transfer.
*/
for (retry = 0; retry < TFTP_RETRIES; retry++)
{
/* Send the read request using the well-known port number before
* receiving the first block. Each retry of the first block will
* re-send the request.
*/
if (blockno == 1)
{
len = tftp_mkreqpacket(packet, TFTP_RRQ, remote, binary);
server.sin_port = HTONS(CONFIG_NETUTILS_TFTP_PORT);
ret = tftp_sendto(sd, packet, len, &server);
if (ret != len)
{
goto errout_with_sd;
}
/* Subsequent sendto will use the port number selected by the TFTP
* server in the DATA packet. Setting the server port to zero
* here indicates that we have not yet received the server port number.
*/
server.sin_port = 0;
}
/* Get the next packet from the server */
nbytesrecvd = tftp_recvfrom(sd, packet, TFTP_IOBUFSIZE, &from);
/* Check if anything valid was received */
if (nbytesrecvd >= 0)
{
/* Verify the sender address and port number */
if (server.sin_addr.s_addr != from.sin_addr.s_addr)
{
nvdbg("Invalid address in DATA\n");
retry--;
continue;
}
if (server.sin_port && server.sin_port != from.sin_port)
{
nvdbg("Invalid port in DATA\n");
len = tftp_mkerrpacket(packet, TFTP_ERR_UNKID, TFTP_ERRST_UNKID);
ret = tftp_sendto(sd, packet, len, &from);
retry--;
continue;
}
/* Parse the incoming DATA packet */
if (nbytesrecvd < TFTP_DATAHEADERSIZE)
{
/* Packet is not big enough to be parsed */
nvdbg("Tiny data packet ignored\n");
continue;
}
if (tftp_parsedatapacket(packet, &opcode, &rblockno) != OK ||
blockno != rblockno)
{
/* Opcode is not TFTP_DATA or the block number is unexpected */
nvdbg("Parse failure\n");
if (opcode > TFTP_MAXRFC1350)
{
len = tftp_mkerrpacket(packet, TFTP_ERR_ILLEGALOP, TFTP_ERRST_ILLEGALOP);
ret = tftp_sendto(sd, packet, len, &from);
}
continue;
}
/* Replace the server port to the one in the good data response */
if (!server.sin_port)
{
server.sin_port = from.sin_port;
}
/* Then break out of the loop */
break;
}
}
/* Did we exhaust all of the retries? */
if (retry == TFTP_RETRIES)
{
nvdbg("Retry limit exceeded\n");
goto errout_with_sd;
}
/* Write the received data chunk to the file */
ndatabytes = nbytesrecvd - TFTP_DATAHEADERSIZE;
tftp_dumpbuffer("Recvd DATA", packet + TFTP_DATAHEADERSIZE, ndatabytes);
if (tftp_write(fd, packet + TFTP_DATAHEADERSIZE, ndatabytes) < 0)
{
goto errout_with_sd;
}
/* Send the acknowledgment */
len = tftp_mkackpacket(packet, blockno);
ret = tftp_sendto(sd, packet, len, &server);
if (ret != len)
{
goto errout_with_sd;
}
nvdbg("ACK blockno %d\n", blockno);
}
while (ndatabytes >= TFTP_DATASIZE);
/* Return success */
result = OK;
errout_with_sd:
close(sd);
errout_with_fd:
close(fd);
errout_with_packet:
free(packet);
errout:
return result;
}
static int tftp_rcvack(int sd, uint8_t *packet, struct sockaddr_in *server,
uint16_t *port, uint16_t *blockno)
{
struct sockaddr_in from; /* The address the last UDP message recv'd from */
ssize_t nbytes; /* The number of bytes received. */
uint16_t opcode; /* The received opcode */
uint16_t rblockno; /* The received block number */
int packetlen; /* Packet length */
int retry; /* Retry counter */
/* Try up to TFTP_RETRIES times */
for (retry = 0; retry < TFTP_RETRIES; retry++)
{
/* Try for until a valid ACK is received or some error occurs */
for (;;)
{
/* Receive the next UDP packet from the server */
nbytes = tftp_recvfrom(sd, packet, TFTP_IOBUFSIZE, &from);
if (nbytes < TFTP_ACKHEADERSIZE)
{
/* Failed to receive a good packet */
if (nbytes == 0)
{
ndbg("Connection lost: %d bytes\n", nbytes);
}
else if (nbytes > 0)
{
ndbg("Short packet: %d bytes\n", nbytes);
}
else
{
ndbg("Recveid failure\n");
}
/* Break out to bump up the retry count */
break;
}
else
{
/* Get the port being used by the server if that has not yet been established */
if (!*port)
{
*port = from.sin_port;
server->sin_port = from.sin_port;
}
/* Verify that the packet was received from the correct host and port */
if (server->sin_addr.s_addr != from.sin_addr.s_addr)
{
nvdbg("Invalid address in DATA\n");
continue;
}
if (*port != server->sin_port)
{
nvdbg("Invalid port in DATA\n");
packetlen = tftp_mkerrpacket(packet, TFTP_ERR_UNKID, TFTP_ERRST_UNKID);
(void)tftp_sendto(sd, packet, packetlen, server);
continue;
}
/* Parse the error message */
opcode = (uint16_t)packet[0] << 8 | (uint16_t)packet[1];
rblockno = (uint16_t)packet[2] << 8 | (uint16_t)packet[3];
/* Verify that the message that we received is an ACK for the
* expected block number.
*/
if (opcode != TFTP_ACK)
{
nvdbg("Bad opcode\n");
#if defined(CONFIG_DEBUG) && defined(CONFIG_DEBUG_NET)
if (opcode == TFTP_ERR)
{
(void)tftp_parseerrpacket(packet);
}
else
#endif
if (opcode > TFTP_MAXRFC1350)
{
packetlen = tftp_mkerrpacket(packet, TFTP_ERR_ILLEGALOP, TFTP_ERRST_ILLEGALOP);
(void)tftp_sendto(sd, packet, packetlen, server);
}
/* Break out an bump up the retry count */
break;
}
/* Success! */
nvdbg("Received ACK for block %d\n", rblockno);
*blockno = rblockno;
return OK;
}
}
}
/* We have tried TFTP_RETRIES times */
ndbg("Timeout, Waiting for ACK\n");
return ERROR; /* Will never get here */
}
