1 | /**
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2 | *
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3 | * @file tftp_server.c
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4 | *
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5 | * @author Logan Gunthorpe <logang@deltatee.com>
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6 | * Dirk Ziegelmeier <dziegel@gmx.de>
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7 | *
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8 | * @brief Trivial File Transfer Protocol (RFC 1350)
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9 | *
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10 | * Copyright (c) Deltatee Enterprises Ltd. 2013
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11 | * All rights reserved.
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12 | *
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13 | */
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14 |
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15 | /*
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16 | * Redistribution and use in source and binary forms, with or without
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17 | * modification,are permitted provided that the following conditions are met:
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18 | *
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19 | * 1. Redistributions of source code must retain the above copyright notice,
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20 | * this list of conditions and the following disclaimer.
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21 | * 2. Redistributions in binary form must reproduce the above copyright notice,
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22 | * this list of conditions and the following disclaimer in the documentation
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23 | * and/or other materials provided with the distribution.
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24 | * 3. The name of the author may not be used to endorse or promote products
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25 | * derived from this software without specific prior written permission.
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26 | *
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27 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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28 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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29 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
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30 | * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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31 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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32 | * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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33 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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34 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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35 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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36 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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37 | *
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38 | * Author: Logan Gunthorpe <logang@deltatee.com>
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39 | * Dirk Ziegelmeier <dziegel@gmx.de>
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40 | *
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41 | */
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42 |
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43 | /**
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44 | * @defgroup tftp TFTP server
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45 | * @ingroup apps
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46 | *
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47 | * This is simple TFTP server for the lwIP raw API.
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48 | */
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49 |
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50 | #include "lwip/apps/tftp_server.h"
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51 |
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52 | #if LWIP_UDP
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53 |
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54 | #include "lwip/udp.h"
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55 | #include "lwip/timeouts.h"
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56 | #include "lwip/debug.h"
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57 |
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58 | #define TFTP_MAX_PAYLOAD_SIZE 512
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59 | #define TFTP_HEADER_LENGTH 4
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60 |
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61 | #define TFTP_RRQ 1
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62 | #define TFTP_WRQ 2
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63 | #define TFTP_DATA 3
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64 | #define TFTP_ACK 4
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65 | #define TFTP_ERROR 5
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66 |
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67 | enum tftp_error {
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68 | TFTP_ERROR_FILE_NOT_FOUND = 1,
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69 | TFTP_ERROR_ACCESS_VIOLATION = 2,
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70 | TFTP_ERROR_DISK_FULL = 3,
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71 | TFTP_ERROR_ILLEGAL_OPERATION = 4,
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72 | TFTP_ERROR_UNKNOWN_TRFR_ID = 5,
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73 | TFTP_ERROR_FILE_EXISTS = 6,
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74 | TFTP_ERROR_NO_SUCH_USER = 7
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75 | };
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76 |
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77 | #include <string.h>
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78 |
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79 | struct tftp_state {
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80 | const struct tftp_context *ctx;
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81 | void *handle;
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82 | struct pbuf *last_data;
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83 | struct udp_pcb *upcb;
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84 | ip_addr_t addr;
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85 | u16_t port;
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86 | int timer;
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87 | int last_pkt;
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88 | u16_t blknum;
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89 | u8_t retries;
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90 | u8_t mode_write;
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91 | };
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92 |
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93 | static struct tftp_state tftp_state;
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94 |
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95 | static void tftp_tmr(void *arg);
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96 |
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97 | static void
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98 | close_handle(void)
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99 | {
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100 | tftp_state.port = 0;
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101 | ip_addr_set_any(0, &tftp_state.addr);
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102 |
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103 | if (tftp_state.last_data != NULL) {
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104 | pbuf_free(tftp_state.last_data);
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105 | tftp_state.last_data = NULL;
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106 | }
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107 |
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108 | sys_untimeout(tftp_tmr, NULL);
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109 |
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110 | if (tftp_state.handle) {
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111 | tftp_state.ctx->close(tftp_state.handle);
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112 | tftp_state.handle = NULL;
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113 | LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: closing\n"));
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114 | }
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115 | }
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116 |
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117 | static void
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118 | send_error(const ip_addr_t *addr, u16_t port, enum tftp_error code, const char *str)
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119 | {
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120 | int str_length = strlen(str);
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121 | struct pbuf *p;
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122 | u16_t *payload;
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123 |
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124 | p = pbuf_alloc(PBUF_TRANSPORT, (u16_t)(TFTP_HEADER_LENGTH + str_length + 1), PBUF_RAM);
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125 | if (p == NULL) {
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126 | return;
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127 | }
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128 |
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129 | payload = (u16_t *) p->payload;
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130 | payload[0] = PP_HTONS(TFTP_ERROR);
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131 | payload[1] = lwip_htons(code);
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132 | MEMCPY(&payload[2], str, str_length + 1);
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133 |
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134 | udp_sendto(tftp_state.upcb, p, addr, port);
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135 | pbuf_free(p);
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136 | }
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137 |
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138 | static void
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139 | send_ack(u16_t blknum)
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140 | {
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141 | struct pbuf *p;
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142 | u16_t *payload;
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143 |
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144 | p = pbuf_alloc(PBUF_TRANSPORT, TFTP_HEADER_LENGTH, PBUF_RAM);
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145 | if (p == NULL) {
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146 | return;
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147 | }
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148 | payload = (u16_t *) p->payload;
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149 |
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150 | payload[0] = PP_HTONS(TFTP_ACK);
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151 | payload[1] = lwip_htons(blknum);
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152 | udp_sendto(tftp_state.upcb, p, &tftp_state.addr, tftp_state.port);
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153 | pbuf_free(p);
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154 | }
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155 |
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156 | static void
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157 | resend_data(void)
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158 | {
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159 | struct pbuf *p = pbuf_alloc(PBUF_TRANSPORT, tftp_state.last_data->len, PBUF_RAM);
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160 | if (p == NULL) {
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161 | return;
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162 | }
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163 |
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164 | if (pbuf_copy(p, tftp_state.last_data) != ERR_OK) {
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165 | pbuf_free(p);
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166 | return;
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167 | }
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168 |
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169 | udp_sendto(tftp_state.upcb, p, &tftp_state.addr, tftp_state.port);
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170 | pbuf_free(p);
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171 | }
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172 |
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173 | static void
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174 | send_data(void)
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175 | {
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176 | u16_t *payload;
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177 | int ret;
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178 |
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179 | if (tftp_state.last_data != NULL) {
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180 | pbuf_free(tftp_state.last_data);
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181 | }
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182 |
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183 | tftp_state.last_data = pbuf_alloc(PBUF_TRANSPORT, TFTP_HEADER_LENGTH + TFTP_MAX_PAYLOAD_SIZE, PBUF_RAM);
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184 | if (tftp_state.last_data == NULL) {
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185 | return;
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186 | }
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187 |
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188 | payload = (u16_t *) tftp_state.last_data->payload;
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189 | payload[0] = PP_HTONS(TFTP_DATA);
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190 | payload[1] = lwip_htons(tftp_state.blknum);
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191 |
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192 | ret = tftp_state.ctx->read(tftp_state.handle, &payload[2], TFTP_MAX_PAYLOAD_SIZE);
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193 | if (ret < 0) {
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194 | send_error(&tftp_state.addr, tftp_state.port, TFTP_ERROR_ACCESS_VIOLATION, "Error occured while reading the file.");
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195 | close_handle();
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196 | return;
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197 | }
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198 |
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199 | pbuf_realloc(tftp_state.last_data, (u16_t)(TFTP_HEADER_LENGTH + ret));
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200 | resend_data();
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201 | }
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202 |
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203 | static void
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204 | recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
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205 | {
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206 | u16_t *sbuf = (u16_t *) p->payload;
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207 | int opcode;
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208 |
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209 | LWIP_UNUSED_ARG(arg);
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210 | LWIP_UNUSED_ARG(upcb);
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211 |
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212 | if (((tftp_state.port != 0) && (port != tftp_state.port)) ||
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213 | (!ip_addr_isany_val(tftp_state.addr) && !ip_addr_cmp(&tftp_state.addr, addr))) {
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214 | send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Only one connection at a time is supported");
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215 | pbuf_free(p);
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216 | return;
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217 | }
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218 |
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219 | opcode = sbuf[0];
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220 |
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221 | tftp_state.last_pkt = tftp_state.timer;
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222 | tftp_state.retries = 0;
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223 |
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224 | switch (opcode) {
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225 | case PP_HTONS(TFTP_RRQ): /* fall through */
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226 | case PP_HTONS(TFTP_WRQ): {
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227 | const char tftp_null = 0;
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228 | char filename[TFTP_MAX_FILENAME_LEN + 1];
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229 | char mode[TFTP_MAX_MODE_LEN + 1];
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230 | u16_t filename_end_offset;
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231 | u16_t mode_end_offset;
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232 |
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233 | if (tftp_state.handle != NULL) {
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234 | send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Only one connection at a time is supported");
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235 | break;
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236 | }
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237 |
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238 | sys_timeout(TFTP_TIMER_MSECS, tftp_tmr, NULL);
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239 |
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240 | /* find \0 in pbuf -> end of filename string */
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241 | filename_end_offset = pbuf_memfind(p, &tftp_null, sizeof(tftp_null), 2);
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242 | if ((u16_t)(filename_end_offset - 1) > sizeof(filename)) {
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243 | send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Filename too long/not NULL terminated");
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244 | break;
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245 | }
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246 | pbuf_copy_partial(p, filename, filename_end_offset - 1, 2);
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247 |
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248 | /* find \0 in pbuf -> end of mode string */
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249 | mode_end_offset = pbuf_memfind(p, &tftp_null, sizeof(tftp_null), filename_end_offset + 1);
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250 | if ((u16_t)(mode_end_offset - filename_end_offset) > sizeof(mode)) {
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251 | send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Mode too long/not NULL terminated");
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252 | break;
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253 | }
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254 | pbuf_copy_partial(p, mode, mode_end_offset - filename_end_offset, filename_end_offset + 1);
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255 |
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256 | tftp_state.handle = tftp_state.ctx->open(filename, mode, opcode == PP_HTONS(TFTP_WRQ));
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257 | tftp_state.blknum = 1;
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258 |
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259 | if (!tftp_state.handle) {
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260 | send_error(addr, port, TFTP_ERROR_FILE_NOT_FOUND, "Unable to open requested file.");
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261 | break;
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262 | }
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263 |
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264 | LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: %s request from ", (opcode == PP_HTONS(TFTP_WRQ)) ? "write" : "read"));
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265 | ip_addr_debug_print(TFTP_DEBUG | LWIP_DBG_STATE, addr);
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266 | LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, (" for '%s' mode '%s'\n", filename, mode));
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267 |
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268 | ip_addr_copy(tftp_state.addr, *addr);
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269 | tftp_state.port = port;
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270 |
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271 | if (opcode == PP_HTONS(TFTP_WRQ)) {
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272 | tftp_state.mode_write = 1;
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273 | send_ack(0);
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274 | } else {
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275 | tftp_state.mode_write = 0;
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276 | send_data();
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277 | }
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278 |
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279 | break;
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280 | }
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281 |
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282 | case PP_HTONS(TFTP_DATA): {
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283 | int ret;
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284 | u16_t blknum;
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285 |
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286 | if (tftp_state.handle == NULL) {
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287 | send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "No connection");
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288 | break;
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289 | }
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290 |
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291 | if (tftp_state.mode_write != 1) {
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292 | send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Not a write connection");
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293 | break;
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294 | }
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295 |
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296 | blknum = lwip_ntohs(sbuf[1]);
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297 | if (blknum == tftp_state.blknum) {
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298 | pbuf_remove_header(p, TFTP_HEADER_LENGTH);
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299 |
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300 | ret = tftp_state.ctx->write(tftp_state.handle, p);
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301 | if (ret < 0) {
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302 | send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "error writing file");
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303 | close_handle();
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304 | } else {
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305 | send_ack(blknum);
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306 | }
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307 |
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308 | if (p->tot_len < TFTP_MAX_PAYLOAD_SIZE) {
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309 | close_handle();
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310 | } else {
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311 | tftp_state.blknum++;
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312 | }
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313 | } else if ((u16_t)(blknum + 1) == tftp_state.blknum) {
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314 | /* retransmit of previous block, ack again (casting to u16_t to care for overflow) */
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315 | send_ack(blknum);
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316 | } else {
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317 | send_error(addr, port, TFTP_ERROR_UNKNOWN_TRFR_ID, "Wrong block number");
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318 | }
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319 | break;
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320 | }
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321 |
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322 | case PP_HTONS(TFTP_ACK): {
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323 | u16_t blknum;
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324 | int lastpkt;
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325 |
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326 | if (tftp_state.handle == NULL) {
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327 | send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "No connection");
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328 | break;
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329 | }
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330 |
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331 | if (tftp_state.mode_write != 0) {
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332 | send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Not a read connection");
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333 | break;
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334 | }
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335 |
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336 | blknum = lwip_ntohs(sbuf[1]);
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337 | if (blknum != tftp_state.blknum) {
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338 | send_error(addr, port, TFTP_ERROR_UNKNOWN_TRFR_ID, "Wrong block number");
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339 | break;
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340 | }
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341 |
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342 | lastpkt = 0;
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343 |
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344 | if (tftp_state.last_data != NULL) {
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345 | lastpkt = tftp_state.last_data->tot_len != (TFTP_MAX_PAYLOAD_SIZE + TFTP_HEADER_LENGTH);
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346 | }
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347 |
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348 | if (!lastpkt) {
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349 | tftp_state.blknum++;
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350 | send_data();
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351 | } else {
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352 | close_handle();
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353 | }
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354 |
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355 | break;
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356 | }
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357 |
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358 | default:
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359 | send_error(addr, port, TFTP_ERROR_ILLEGAL_OPERATION, "Unknown operation");
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360 | break;
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361 | }
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362 |
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363 | pbuf_free(p);
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364 | }
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365 |
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366 | static void
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367 | tftp_tmr(void *arg)
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368 | {
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369 | LWIP_UNUSED_ARG(arg);
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370 |
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371 | tftp_state.timer++;
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372 |
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373 | if (tftp_state.handle == NULL) {
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374 | return;
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375 | }
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376 |
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377 | sys_timeout(TFTP_TIMER_MSECS, tftp_tmr, NULL);
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378 |
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379 | if ((tftp_state.timer - tftp_state.last_pkt) > (TFTP_TIMEOUT_MSECS / TFTP_TIMER_MSECS)) {
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380 | if ((tftp_state.last_data != NULL) && (tftp_state.retries < TFTP_MAX_RETRIES)) {
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381 | LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: timeout, retrying\n"));
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382 | resend_data();
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383 | tftp_state.retries++;
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384 | } else {
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385 | LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: timeout\n"));
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386 | close_handle();
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387 | }
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388 | }
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389 | }
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390 |
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391 | /** @ingroup tftp
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392 | * Initialize TFTP server.
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393 | * @param ctx TFTP callback struct
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394 | */
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395 | err_t
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396 | tftp_init(const struct tftp_context *ctx)
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397 | {
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398 | err_t ret;
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399 |
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400 | /* LWIP_ASSERT_CORE_LOCKED(); is checked by udp_new() */
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401 | struct udp_pcb *pcb = udp_new_ip_type(IPADDR_TYPE_ANY);
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402 | if (pcb == NULL) {
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403 | return ERR_MEM;
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404 | }
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405 |
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406 | ret = udp_bind(pcb, IP_ANY_TYPE, TFTP_PORT);
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407 | if (ret != ERR_OK) {
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408 | udp_remove(pcb);
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409 | return ret;
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410 | }
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411 |
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412 | tftp_state.handle = NULL;
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413 | tftp_state.port = 0;
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414 | tftp_state.ctx = ctx;
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415 | tftp_state.timer = 0;
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416 | tftp_state.last_data = NULL;
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417 | tftp_state.upcb = pcb;
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418 |
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419 | udp_recv(pcb, recv, NULL);
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420 |
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421 | return ERR_OK;
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422 | }
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423 |
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424 | /** @ingroup tftp
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425 | * Deinitialize ("turn off") TFTP server.
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426 | */
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427 | void tftp_cleanup(void)
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428 | {
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429 | LWIP_ASSERT("Cleanup called on non-initialized TFTP", tftp_state.upcb != NULL);
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430 | udp_remove(tftp_state.upcb);
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431 | close_handle();
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432 | memset(&tftp_state, 0, sizeof(tftp_state));
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433 | }
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434 |
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435 | #endif /* LWIP_UDP */
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