2 * tftp.c - a simple, read-only tftp server for qemu
4 * Copyright (c) 2004 Magnus Damm <damm@opensource.se>
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26 #include "qemu-common.h" // for pstrcpy
30 unsigned char filename[TFTP_FILENAME_MAX];
32 struct in_addr client_ip;
33 u_int16_t client_port;
38 static struct tftp_session tftp_sessions[TFTP_SESSIONS_MAX];
40 const char *tftp_prefix;
42 static void tftp_session_update(struct tftp_session *spt)
44 spt->timestamp = curtime;
48 static void tftp_session_terminate(struct tftp_session *spt)
53 static int tftp_session_allocate(struct tftp_t *tp)
55 struct tftp_session *spt;
58 for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
59 spt = &tftp_sessions[k];
64 /* sessions time out after 5 inactive seconds */
65 if ((int)(curtime - spt->timestamp) > 5000)
72 memset(spt, 0, sizeof(*spt));
73 memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
74 spt->client_port = tp->udp.uh_sport;
76 tftp_session_update(spt);
81 static int tftp_session_find(struct tftp_t *tp)
83 struct tftp_session *spt;
86 for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
87 spt = &tftp_sessions[k];
90 if (!memcmp(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip))) {
91 if (spt->client_port == tp->udp.uh_sport) {
101 static int tftp_read_data(struct tftp_session *spt, u_int16_t block_nr,
102 u_int8_t *buf, int len)
109 n = snprintf(buffer, sizeof(buffer), "%s/%s",
110 tftp_prefix, spt->filename);
111 if (n >= sizeof(buffer))
114 fd = open(buffer, O_RDONLY | O_BINARY);
121 lseek(fd, block_nr * 512, SEEK_SET);
123 bytes_read = read(fd, buf, len);
131 static int tftp_send_oack(struct tftp_session *spt,
132 const char *key, uint32_t value,
133 struct tftp_t *recv_tp)
135 struct sockaddr_in saddr, daddr;
145 memset(m->m_data, 0, m->m_size);
147 m->m_data += IF_MAXLINKHDR;
148 tp = (void *)m->m_data;
149 m->m_data += sizeof(struct udpiphdr);
151 tp->tp_op = htons(TFTP_OACK);
152 n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
154 n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
157 saddr.sin_addr = recv_tp->ip.ip_dst;
158 saddr.sin_port = recv_tp->udp.uh_dport;
160 daddr.sin_addr = spt->client_ip;
161 daddr.sin_port = spt->client_port;
163 m->m_len = sizeof(struct tftp_t) - 514 + n -
164 sizeof(struct ip) - sizeof(struct udphdr);
165 udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
172 static int tftp_send_error(struct tftp_session *spt,
173 u_int16_t errorcode, const char *msg,
174 struct tftp_t *recv_tp)
176 struct sockaddr_in saddr, daddr;
187 memset(m->m_data, 0, m->m_size);
189 m->m_data += IF_MAXLINKHDR;
190 tp = (void *)m->m_data;
191 m->m_data += sizeof(struct udpiphdr);
193 tp->tp_op = htons(TFTP_ERROR);
194 tp->x.tp_error.tp_error_code = htons(errorcode);
195 pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg), msg);
197 saddr.sin_addr = recv_tp->ip.ip_dst;
198 saddr.sin_port = recv_tp->udp.uh_dport;
200 daddr.sin_addr = spt->client_ip;
201 daddr.sin_port = spt->client_port;
205 m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg) -
206 sizeof(struct ip) - sizeof(struct udphdr);
208 udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
210 tftp_session_terminate(spt);
215 static int tftp_send_data(struct tftp_session *spt,
217 struct tftp_t *recv_tp)
219 struct sockaddr_in saddr, daddr;
234 memset(m->m_data, 0, m->m_size);
236 m->m_data += IF_MAXLINKHDR;
237 tp = (void *)m->m_data;
238 m->m_data += sizeof(struct udpiphdr);
240 tp->tp_op = htons(TFTP_DATA);
241 tp->x.tp_data.tp_block_nr = htons(block_nr);
243 saddr.sin_addr = recv_tp->ip.ip_dst;
244 saddr.sin_port = recv_tp->udp.uh_dport;
246 daddr.sin_addr = spt->client_ip;
247 daddr.sin_port = spt->client_port;
249 nobytes = tftp_read_data(spt, block_nr - 1, tp->x.tp_data.tp_buf, 512);
254 /* send "file not found" error back */
256 tftp_send_error(spt, 1, "File not found", tp);
261 m->m_len = sizeof(struct tftp_t) - (512 - nobytes) -
262 sizeof(struct ip) - sizeof(struct udphdr);
264 udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
266 if (nobytes == 512) {
267 tftp_session_update(spt);
270 tftp_session_terminate(spt);
276 static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
278 struct tftp_session *spt;
282 s = tftp_session_allocate(tp);
288 spt = &tftp_sessions[s];
292 n = pktlen - ((uint8_t *)&tp->x.tp_buf[0] - (uint8_t *)tp);
296 for (k = 0; k < n; k++) {
297 if (k < TFTP_FILENAME_MAX) {
304 if (src[k] == '\0') {
320 if (memcmp(&src[k], "octet\0", 6) != 0) {
321 tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
325 k += 6; /* skipping octet */
327 /* do sanity checks on the filename */
329 if ((spt->filename[0] != '/')
330 || (spt->filename[strlen((char *)spt->filename) - 1] == '/')
331 || strstr((char *)spt->filename, "/../")) {
332 tftp_send_error(spt, 2, "Access violation", tp);
336 /* only allow exported prefixes */
339 tftp_send_error(spt, 2, "Access violation", tp);
343 /* check if the file exists */
345 if (tftp_read_data(spt, 0, spt->filename, 0) < 0) {
346 tftp_send_error(spt, 1, "File not found", tp);
350 if (src[n - 1] != 0) {
351 tftp_send_error(spt, 2, "Access violation", tp);
356 const char *key, *value;
358 key = (char *)src + k;
359 k += strlen(key) + 1;
362 tftp_send_error(spt, 2, "Access violation", tp);
366 value = (char *)src + k;
367 k += strlen(value) + 1;
369 if (strcmp(key, "tsize") == 0) {
370 int tsize = atoi(value);
373 if (tsize == 0 && tftp_prefix) {
377 len = snprintf(buffer, sizeof(buffer), "%s/%s",
378 tftp_prefix, spt->filename);
380 if (stat(buffer, &stat_p) == 0)
381 tsize = stat_p.st_size;
383 tftp_send_error(spt, 1, "File not found", tp);
388 tftp_send_oack(spt, "tsize", tsize, tp);
392 tftp_send_data(spt, 1, tp);
395 static void tftp_handle_ack(struct tftp_t *tp, int pktlen)
399 s = tftp_session_find(tp);
405 if (tftp_send_data(&tftp_sessions[s],
406 ntohs(tp->x.tp_data.tp_block_nr) + 1,
412 void tftp_input(struct mbuf *m)
414 struct tftp_t *tp = (struct tftp_t *)m->m_data;
416 switch(ntohs(tp->tp_op)) {
418 tftp_handle_rrq(tp, m->m_len);
422 tftp_handle_ack(tp, m->m_len);