Working

bertos/net/tftp.c

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+/**
+ * \file
+ * <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction.  Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License.  This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2010 Develer S.r.l. (http://www.develer.com/)
+ *
+ * -->
+ *
+ * \brief TFTP protocol implementation
+ *
+ * \author Luca Ottaviano <lottaviano@develer.com>
+ *
+ * notest:all
+ */
+
+#include "tftp.h"
+#include "cfg/cfg_tftp.h"
+#define LOG_LEVEL   TFTP_LOG_LEVEL
+#define LOG_FORMAT  TFTP_LOG_FORMAT
+#include <cfg/log.h>
+
+//#include <lwip/in.h>
+#include <lwip/inet.h>
+#include <lwip/sockets.h>
+#include <string.h> //memset
+
+#define TFTP_PACKET_SIZE 516
+
+#define DECLARE_TIMEOUT(name, timeout) \
+	struct timeval name; \
+	name.tv_sec = timeout / 1000; \
+	name.tv_usec = (timeout % 1000) * 1000;
+
+#define KFT_TFTPSESSION MAKE_ID('T', 'F', 'T', 'P')
+INLINE TftpSession *TFTP_CAST(KFile *fd)
+{
+	ASSERT(fd->_type == KFT_TFTPSESSION);
+	return (TftpSession *)containerof(fd, TftpSession, kfile_request);
+}
+
+/*
+ * Check if received data is correct and send ACK if ok.
+ */
+static int checkPacket(TftpSession *ctx, const Tftpframe *frame)
+{
+	LOG_INFO("Checking block %hd\n", ctx->block);
+	if (ntohs(frame->hdr.opcode) != TFTP_DATA)
+	{
+		LOG_INFO("Opcode != TFTP_DATA (%hd != %d)\n", ntohs(frame->hdr.opcode), TFTP_DATA);
+		return -1;
+	}
+	if (ntohs(frame->hdr.th_u.block) != ctx->block + 1)
+		return -1;
+
+	ctx->block++;
+	// if everything was ok, send ACK
+	// ACK is already in network order
+	struct ackframe ack;
+	ack.opcode = TFTP_ACK;
+	ack.block_num = htons(ctx->block);
+	ssize_t rc = lwip_sendto(ctx->sock, &ack, 4, 0, (struct sockaddr *)&ctx->addr, ctx->addr_len);
+	if (rc == 4)
+		return rc;
+	else
+		return -1;
+}
+
+/*
+ * Return >0 if there's something to read in ctx, 0 on timeout, -1 on errors
+ */
+static int tftp_waitEvent(TftpSession *ctx, struct timeval *timeout)
+{
+	fd_set inset;
+	FD_ZERO(&inset);
+	FD_SET(ctx->sock, &inset);
+	struct timeval tmp = *timeout;
+	return lwip_select(ctx->sock + 1, &inset, NULL, NULL, &tmp);
+}
+
+/*
+ * Read a block from TFTP.
+ * \param size Must be exactly 516 bytes
+ * \param timeout Time to wait the network connection, may be NULL to wait forever
+ * \return Number of bytes read if success, TFTP_ERR_TIMEOUT on timeout, TFTP_ERR otherwise
+ */
+static ssize_t tftp_readPacket(TftpSession *ctx, Tftpframe *frame, mtime_t timeout)
+{
+	DECLARE_TIMEOUT(wait_tm, timeout);
+
+	int res = tftp_waitEvent(ctx, &wait_tm);
+	if (res == 0)
+		return TFTP_ERR_TIMEOUT;
+	if (res == -1)
+		return TFTP_ERR;
+
+	ssize_t rlen = lwip_recvfrom(ctx->sock, frame, sizeof(Tftpframe), 0, NULL, NULL);
+	LOG_INFO("Received %zd bytes\n", rlen);
+	if (rlen > 0 && (checkPacket(ctx, frame) > 0))
+		return rlen;
+	else
+		return TFTP_ERR;
+}
+
+static size_t tftp_read(struct KFile *fd, void *buf, size_t size)
+{
+	TftpSession *fds = TFTP_CAST(fd);
+	uint8_t *_buf = (uint8_t *) buf;
+	size_t read_bytes = 0;
+	size_t offset = fds->valid_data - fds->bytes_available;
+
+	if (fds->pending_ack)
+	{
+		ASSERT(fds->block == 0);
+		struct ackframe ack;
+		ack.opcode = TFTP_ACK;
+		ack.block_num = fds->block;
+		lwip_sendto(fds->sock, &ack, 4, 0, (struct sockaddr *)&fds->addr, fds->addr_len);
+		fds->pending_ack = false;
+	}
+
+	if (fds->bytes_available < size)
+	{
+		/* check if we were called again after an error */
+		if (fds->bytes_available > 0)
+		{
+			memcpy(_buf, fds->frame.data + offset, fds->bytes_available);
+			LOG_INFO("ba < size. Copied %zd bytes from offset %zd\n", fds->bytes_available, offset);
+			/* adjust buf and size */
+			_buf += fds->bytes_available;
+			size -= fds->bytes_available;
+			read_bytes += fds->bytes_available;
+		}
+
+		if (!fds->is_xfer_end)
+		{
+			LOG_INFO("Waiting for new TFTP packet\n");
+			/* get more data, we can wait since the function is blocking */
+			ssize_t rd = tftp_readPacket(fds, &fds->frame, fds->timeout);
+			if (rd < 0)
+			{
+				fds->bytes_available = 0;
+				fds->error = rd;
+				return 0;
+			}
+			else
+			{
+				if (rd < TFTP_PACKET_SIZE)
+				{
+					fds->is_xfer_end = true;
+					LOG_INFO("Received the last packet\n");
+				}
+				fds->bytes_available = (size_t)rd - sizeof(struct TftpHeader);
+				fds->valid_data = fds->bytes_available;
+				offset = 0;
+			}
+		}
+		else
+		{
+			LOG_INFO("Transfer finished\n");
+			fds->bytes_available -= fds->bytes_available;
+			fds->valid_data = 0;
+			return read_bytes;
+		}
+	}
+
+	/* check how many bytes we need to copy */
+	size_t res = MIN(fds->bytes_available, size);
+	LOG_INFO("Copying %zd bytes from offset %zd\n", res, offset);
+	memcpy(_buf, fds->frame.data + offset, res);
+	fds->bytes_available -= res;
+	read_bytes += res;
+	return read_bytes;
+}
+
+static int tftp_error(struct KFile *fd)
+{
+	TftpSession *fds = TFTP_CAST(fd);
+	return fds->error;
+}
+
+static void tftp_clearerr(struct KFile *fd)
+{
+	TftpSession *fds = TFTP_CAST(fd);
+	fds->error = 0;
+}
+
+static int tftp_close(struct KFile *fd)
+{
+	TftpSession *fds = TFTP_CAST(fd);
+	struct errframe err;
+	if (fds->pending_ack)
+	{
+		err.opcode = TFTP_PROTOERR;
+		err.errcode = TFTP_PROTOERR_ACCESS_VIOLATION;
+		err.str = '\0';
+		lwip_sendto(fds->sock, &err, 5, 0, (struct sockaddr *)&fds->addr, fds->addr_len);
+		LOG_INFO("Closed connection upon user request\n");
+	}
+	return 0;
+}
+
+static void resetTftpState(TftpSession *ctx)
+{
+	ctx->block = 0;
+	ctx->error = 0;
+	ctx->bytes_available = 0;
+	ctx->valid_data = 0;
+	ctx->is_xfer_end = false;
+	ctx->pending_ack = false;
+}
+
+/**
+ * Listen for incoming tftp sessions.
+ *
+ * \note Only write requests are accepted.
+ *
+ * \param ctx Initialized TftpChannel
+ * \param filename String to be filled with file name to be written
+ * \param len Length of the filename
+ * \param mode Open mode for the returned KFile
+ * \return KFile pointer to read from
+ */
+KFile *tftp_listen(TftpSession *ctx, char *filename, size_t len, TftpOpenMode *mode)
+{
+	DECLARE_TIMEOUT(wait_tm, ctx->timeout);
+	resetTftpState(ctx);
+
+	int res = tftp_waitEvent(ctx, &wait_tm);
+	if (res == 0)
+	{
+		ctx->error = TFTP_ERR_TIMEOUT;
+		return NULL;
+	}
+	if (res == -1)
+	{
+		ctx->error = TFTP_ERR;
+		return NULL;
+	}
+
+	// listen onto TFTP port
+	ctx->addr_len = sizeof(ctx->addr);
+	ssize_t rd = 0;
+	if ((rd = lwip_recvfrom(ctx->sock, &ctx->frame, sizeof(Tftpframe), 0, (struct sockaddr *)&ctx->addr, &ctx->addr_len)) > 0)
+	{
+		// check if the packet is WRQ, otherwise discard the packet
+		if (ctx->frame.hdr.opcode == TFTP_WRQ)
+		{
+			*mode = TFTP_WRITE;
+			ctx->pending_ack = true;
+			strncpy(filename, (char *)&ctx->frame.hdr.th_u, len);
+			filename[len - 1] = '\0';
+			ctx->error = 0;
+			return &ctx->kfile_request;
+		}
+		else
+			*mode = TFTP_READ;
+	}
+	ctx->error = TFTP_ERR;
+	return NULL;
+}
+
+/**
+ * Init a server session
+ *
+ * Create a IPv4 session on all addresses and port \a port.
+ *
+ * \param ctx Context to be initialized as server
+ * \param port Port to listen incoming connections
+ * \param timeout Timeout to be used for tftp connections
+ * \return 0 if successful, -1 otherwise
+ */
+int tftp_init(TftpSession *ctx, unsigned short port, mtime_t timeout)
+{
+	DB(ctx->kfile_request._type = KFT_TFTPSESSION);
+	ctx->kfile_request.read = tftp_read;
+	ctx->kfile_request.error = tftp_error;
+	ctx->kfile_request.clearerr = tftp_clearerr;
+	ctx->kfile_request.close = tftp_close;
+	resetTftpState(ctx);
+
+	/* Unused kfile methods */
+	ctx->kfile_request.seek = NULL;
+	ctx->kfile_request.write = NULL;
+	ctx->kfile_request.flush = NULL;
+	ctx->kfile_request.reopen = NULL;
+
+	struct sockaddr_in sa;
+	sa.sin_family = AF_INET;
+        sa.sin_addr.s_addr = htonl(INADDR_ANY);
+        sa.sin_port = htons(port);
+	ctx->timeout = timeout;
+
+	ctx->sock = lwip_socket(AF_INET, SOCK_DGRAM, 0);
+	if (ctx->sock == -1)
+	{
+		LOG_INFO("TFTP socket error\n");
+		return -1;
+	}
+
+	if(lwip_bind(ctx->sock, (struct sockaddr *)&sa, sizeof(sa)))
+	{
+		LOG_INFO("Error binding socket\n");
+		return -1;
+	}
+	return 0;
+}
+