/****************************************************************//** * * @file tftp_server.c * * @author Logan Gunthorpe * Dirk Ziegelmeier * * @brief Trivial File Transfer Protocol (RFC 1350) * * Copyright (c) Deltatee Enterprises Ltd. 2013 * All rights reserved. * ********************************************************************/ /* * Redistribution and use in source and binary forms, with or without * modification,are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * Author: Logan Gunthorpe * Dirk Ziegelmeier * */ /** * @defgroup tftp TFTP server * @ingroup apps * * This is simple TFTP server for the lwIP raw API. */ #include "lwip/apps/tftp_server.h" #if LWIP_UDP #include "lwip/udp.h" #include "lwip/timeouts.h" #include "lwip/debug.h" #define TFTP_MAX_PAYLOAD_SIZE 512 #define TFTP_HEADER_LENGTH 4 #define TFTP_RRQ 1 #define TFTP_WRQ 2 #define TFTP_DATA 3 #define TFTP_ACK 4 #define TFTP_ERROR 5 enum tftp_error { TFTP_ERROR_FILE_NOT_FOUND = 1, TFTP_ERROR_ACCESS_VIOLATION = 2, TFTP_ERROR_DISK_FULL = 3, TFTP_ERROR_ILLEGAL_OPERATION = 4, TFTP_ERROR_UNKNOWN_TRFR_ID = 5, TFTP_ERROR_FILE_EXISTS = 6, TFTP_ERROR_NO_SUCH_USER = 7 }; #include struct tftp_state { const struct tftp_context *ctx; void *handle; struct pbuf *last_data; struct udp_pcb *upcb; ip_addr_t addr; u16_t port; int timer; int last_pkt; u16_t blknum; u8_t retries; u8_t mode_write; }; static struct tftp_state tftp_state; static void tftp_tmr(void* arg); static void close_handle(void) { tftp_state.port = 0; ip_addr_set_any(0, &tftp_state.addr); if(tftp_state.last_data != NULL) { pbuf_free(tftp_state.last_data); tftp_state.last_data = NULL; } sys_untimeout(tftp_tmr, NULL); if (tftp_state.handle) { tftp_state.ctx->close(tftp_state.handle); tftp_state.handle = NULL; LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: closing\n")); } } static void send_error(const ip_addr_t *addr, u16_t port, enum tftp_error code, const char *str) { int str_length = strlen(str); struct pbuf* p; u16_t* payload; p = pbuf_alloc(PBUF_TRANSPORT, (u16_t)(TFTP_HEADER_LENGTH + str_length + 1), PBUF_RAM); if(p == NULL) { return; } payload = (u16_t*) p->payload; payload[0] = PP_HTONS(TFTP_ERROR); payload[1] = lwip_htons(code); MEMCPY(&payload[2], str, str_length + 1); udp_sendto(tftp_state.upcb, p, addr, port); pbuf_free(p); } static void send_ack(u16_t blknum) { struct pbuf* p; u16_t* payload; p = pbuf_alloc(PBUF_TRANSPORT, TFTP_HEADER_LENGTH, PBUF_RAM); if(p == NULL) { return; } payload = (u16_t*) p->payload; payload[0] = PP_HTONS(TFTP_ACK); payload[1] = lwip_htons(blknum); udp_sendto(tftp_state.upcb, p, &tftp_state.addr, tftp_state.port); pbuf_free(p); } static void resend_data(void) { struct pbuf *p = pbuf_alloc(PBUF_TRANSPORT, tftp_state.last_data->len, PBUF_RAM); if(p == NULL) { return; } if(pbuf_copy(p, tftp_state.last_data) != ERR_OK) { pbuf_free(p); return; } udp_sendto(tftp_state.upcb, p, &tftp_state.addr, tftp_state.port); pbuf_free(p); } static void send_data(void) { u16_t *payload; int ret; if(tftp_state.last_data != NULL) { pbuf_free(tftp_state.last_data); } tftp_state.last_data = pbuf_alloc(PBUF_TRANSPORT, TFTP_HEADER_LENGTH + TFTP_MAX_PAYLOAD_SIZE, PBUF_RAM); if(tftp_state.last_data == NULL) { return; } payload = (u16_t *) tftp_state.last_data->payload; payload[0] = PP_HTONS(TFTP_DATA); payload[1] = lwip_htons(tftp_state.blknum); ret = tftp_state.ctx->read(tftp_state.handle, &payload[2], TFTP_MAX_PAYLOAD_SIZE); if (ret < 0) { send_error(&tftp_state.addr, tftp_state.port, TFTP_ERROR_ACCESS_VIOLATION, "Error occured while reading the file."); close_handle(); return; } pbuf_realloc(tftp_state.last_data, (u16_t)(TFTP_HEADER_LENGTH + ret)); resend_data(); } static void recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port) { u16_t *sbuf = (u16_t *) p->payload; int opcode; LWIP_UNUSED_ARG(arg); LWIP_UNUSED_ARG(upcb); if (((tftp_state.port != 0) && (port != tftp_state.port)) || (!ip_addr_isany_val(tftp_state.addr) && !ip_addr_cmp(&tftp_state.addr, addr))) { send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Only one connection at a time is supported"); pbuf_free(p); return; } opcode = sbuf[0]; tftp_state.last_pkt = tftp_state.timer; tftp_state.retries = 0; switch (opcode) { case PP_HTONS(TFTP_RRQ): /* fall through */ case PP_HTONS(TFTP_WRQ): { const char tftp_null = 0; char filename[TFTP_MAX_FILENAME_LEN+1]; char mode[TFTP_MAX_MODE_LEN+1]; u16_t filename_end_offset; u16_t mode_end_offset; if(tftp_state.handle != NULL) { send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Only one connection at a time is supported"); break; } sys_timeout(TFTP_TIMER_MSECS, tftp_tmr, NULL); /* find \0 in pbuf -> end of filename string */ filename_end_offset = pbuf_memfind(p, &tftp_null, sizeof(tftp_null), 2); if((u16_t)(filename_end_offset-1) > sizeof(filename)) { send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Filename too long/not NULL terminated"); break; } pbuf_copy_partial(p, filename, filename_end_offset-1, 2); /* find \0 in pbuf -> end of mode string */ mode_end_offset = pbuf_memfind(p, &tftp_null, sizeof(tftp_null), filename_end_offset+1); if((u16_t)(mode_end_offset-filename_end_offset) > sizeof(mode)) { send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Mode too long/not NULL terminated"); break; } pbuf_copy_partial(p, mode, mode_end_offset-filename_end_offset, filename_end_offset+1); tftp_state.handle = tftp_state.ctx->open(filename, mode, opcode == PP_HTONS(TFTP_WRQ)); tftp_state.blknum = 1; if (!tftp_state.handle) { send_error(addr, port, TFTP_ERROR_FILE_NOT_FOUND, "Unable to open requested file."); break; } LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: %s request from ", (opcode == PP_HTONS(TFTP_WRQ)) ? "write" : "read")); ip_addr_debug_print(TFTP_DEBUG | LWIP_DBG_STATE, addr); LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, (" for '%s' mode '%s'\n", filename, mode)); ip_addr_copy(tftp_state.addr, *addr); tftp_state.port = port; if (opcode == PP_HTONS(TFTP_WRQ)) { tftp_state.mode_write = 1; send_ack(0); } else { tftp_state.mode_write = 0; send_data(); } break; } case PP_HTONS(TFTP_DATA): { int ret; u16_t blknum; if (tftp_state.handle == NULL) { send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "No connection"); break; } if (tftp_state.mode_write != 1) { send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Not a write connection"); break; } blknum = lwip_ntohs(sbuf[1]); pbuf_header(p, -TFTP_HEADER_LENGTH); ret = tftp_state.ctx->write(tftp_state.handle, p); if (ret < 0) { send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "error writing file"); close_handle(); } else { send_ack(blknum); } if (p->tot_len < TFTP_MAX_PAYLOAD_SIZE) { close_handle(); } break; } case PP_HTONS(TFTP_ACK): { u16_t blknum; int lastpkt; if (tftp_state.handle == NULL) { send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "No connection"); break; } if (tftp_state.mode_write != 0) { send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Not a read connection"); break; } blknum = lwip_ntohs(sbuf[1]); if (blknum != tftp_state.blknum) { send_error(addr, port, TFTP_ERROR_UNKNOWN_TRFR_ID, "Wrong block number"); break; } lastpkt = 0; if (tftp_state.last_data != NULL) { lastpkt = tftp_state.last_data->tot_len != (TFTP_MAX_PAYLOAD_SIZE + TFTP_HEADER_LENGTH); } if (!lastpkt) { tftp_state.blknum++; send_data(); } else { close_handle(); } break; } default: send_error(addr, port, TFTP_ERROR_ILLEGAL_OPERATION, "Unknown operation"); break; } pbuf_free(p); } static void tftp_tmr(void* arg) { LWIP_UNUSED_ARG(arg); tftp_state.timer++; if (tftp_state.handle == NULL) { return; } sys_timeout(TFTP_TIMER_MSECS, tftp_tmr, NULL); if ((tftp_state.timer - tftp_state.last_pkt) > (TFTP_TIMEOUT_MSECS / TFTP_TIMER_MSECS)) { if ((tftp_state.last_data != NULL) && (tftp_state.retries < TFTP_MAX_RETRIES)) { LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: timeout, retrying\n")); resend_data(); tftp_state.retries++; } else { LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: timeout\n")); close_handle(); } } } /** @ingroup tftp * Initialize TFTP server. * @param ctx TFTP callback struct */ err_t tftp_init(const struct tftp_context *ctx) { err_t ret; struct udp_pcb *pcb = udp_new_ip_type(IPADDR_TYPE_ANY); if (pcb == NULL) { return ERR_MEM; } ret = udp_bind(pcb, IP_ANY_TYPE, TFTP_PORT); if (ret != ERR_OK) { udp_remove(pcb); return ret; } tftp_state.handle = NULL; tftp_state.port = 0; tftp_state.ctx = ctx; tftp_state.timer = 0; tftp_state.last_data = NULL; tftp_state.upcb = pcb; udp_recv(pcb, recv, NULL); return ERR_OK; } #endif /* LWIP_UDP */