[qemu.git] / slirp / tftp.c

/*
 * tftp.c - a simple, read-only tftp server for qemu
 *
 * Copyright (c) 2004 Magnus Damm <damm@opensource.se>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include <slirp.h>
#include "qemu-common.h"

struct tftp_session {
    int in_use;
    char *filename;

    struct in_addr client_ip;
    u_int16_t client_port;

    int timestamp;
};

static struct tftp_session tftp_sessions[TFTP_SESSIONS_MAX];

char *tftp_prefix;

static void tftp_session_update(struct tftp_session *spt)
{
    spt->timestamp = curtime;
    spt->in_use = 1;
}

static void tftp_session_terminate(struct tftp_session *spt)
{
  qemu_free(spt->filename);
  spt->in_use = 0;
}

static int tftp_session_allocate(struct tftp_t *tp)
{
  struct tftp_session *spt;
  int k;

  for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
    spt = &tftp_sessions[k];

    if (!spt->in_use)
        goto found;

    /* sessions time out after 5 inactive seconds */
    if ((int)(curtime - spt->timestamp) > 5000) {
        qemu_free(spt->filename);
        goto found;
    }
  }

  return -1;

 found:
  memset(spt, 0, sizeof(*spt));
  memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
  spt->client_port = tp->udp.uh_sport;

  tftp_session_update(spt);

  return k;
}

static int tftp_session_find(struct tftp_t *tp)
{
  struct tftp_session *spt;
  int k;

  for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
    spt = &tftp_sessions[k];

    if (spt->in_use) {
      if (!memcmp(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip))) {
	if (spt->client_port == tp->udp.uh_sport) {
	  return k;
	}
      }
    }
  }

  return -1;
}

static int tftp_read_data(struct tftp_session *spt, u_int16_t block_nr,
			  u_int8_t *buf, int len)
{
  int fd;
  int bytes_read = 0;

  fd = open(spt->filename, O_RDONLY | O_BINARY);

  if (fd < 0) {
    return -1;
  }

  if (len) {
    lseek(fd, block_nr * 512, SEEK_SET);

    bytes_read = read(fd, buf, len);
  }

  close(fd);

  return bytes_read;
}

static int tftp_send_oack(struct tftp_session *spt,
                          const char *key, uint32_t value,
                          struct tftp_t *recv_tp)
{
    struct sockaddr_in saddr, daddr;
    struct mbuf *m;
    struct tftp_t *tp;
    int n = 0;

    m = m_get();

    if (!m)
	return -1;

    memset(m->m_data, 0, m->m_size);

    m->m_data += IF_MAXLINKHDR;
    tp = (void *)m->m_data;
    m->m_data += sizeof(struct udpiphdr);

    tp->tp_op = htons(TFTP_OACK);
    n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
                  key) + 1;
    n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
                  value) + 1;

    saddr.sin_addr = recv_tp->ip.ip_dst;
    saddr.sin_port = recv_tp->udp.uh_dport;

    daddr.sin_addr = spt->client_ip;
    daddr.sin_port = spt->client_port;

    m->m_len = sizeof(struct tftp_t) - 514 + n -
        sizeof(struct ip) - sizeof(struct udphdr);
    udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);

    return 0;
}

static void tftp_send_error(struct tftp_session *spt,
                            u_int16_t errorcode, const char *msg,
                            struct tftp_t *recv_tp)
{
  struct sockaddr_in saddr, daddr;
  struct mbuf *m;
  struct tftp_t *tp;
  int nobytes;

  m = m_get();

  if (!m) {
    goto out;
  }

  memset(m->m_data, 0, m->m_size);

  m->m_data += IF_MAXLINKHDR;
  tp = (void *)m->m_data;
  m->m_data += sizeof(struct udpiphdr);

  tp->tp_op = htons(TFTP_ERROR);
  tp->x.tp_error.tp_error_code = htons(errorcode);
  pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg), msg);

  saddr.sin_addr = recv_tp->ip.ip_dst;
  saddr.sin_port = recv_tp->udp.uh_dport;

  daddr.sin_addr = spt->client_ip;
  daddr.sin_port = spt->client_port;

  nobytes = 2;

  m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg) -
        sizeof(struct ip) - sizeof(struct udphdr);

  udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);

out:
  tftp_session_terminate(spt);
}

static int tftp_send_data(struct tftp_session *spt,
			  u_int16_t block_nr,
			  struct tftp_t *recv_tp)
{
  struct sockaddr_in saddr, daddr;
  struct mbuf *m;
  struct tftp_t *tp;
  int nobytes;

  if (block_nr < 1) {
    return -1;
  }

  m = m_get();

  if (!m) {
    return -1;
  }

  memset(m->m_data, 0, m->m_size);

  m->m_data += IF_MAXLINKHDR;
  tp = (void *)m->m_data;
  m->m_data += sizeof(struct udpiphdr);

  tp->tp_op = htons(TFTP_DATA);
  tp->x.tp_data.tp_block_nr = htons(block_nr);

  saddr.sin_addr = recv_tp->ip.ip_dst;
  saddr.sin_port = recv_tp->udp.uh_dport;

  daddr.sin_addr = spt->client_ip;
  daddr.sin_port = spt->client_port;

  nobytes = tftp_read_data(spt, block_nr - 1, tp->x.tp_data.tp_buf, 512);

  if (nobytes < 0) {
    m_free(m);

    /* send "file not found" error back */

    tftp_send_error(spt, 1, "File not found", tp);

    return -1;
  }

  m->m_len = sizeof(struct tftp_t) - (512 - nobytes) -
        sizeof(struct ip) - sizeof(struct udphdr);

  udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);

  if (nobytes == 512) {
    tftp_session_update(spt);
  }
  else {
    tftp_session_terminate(spt);
  }

  return 0;
}

static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
{
  struct tftp_session *spt;
  int s, k;
  size_t prefix_len;
  char *req_fname;

  s = tftp_session_allocate(tp);

  if (s < 0) {
    return;
  }

  spt = &tftp_sessions[s];

  /* unspecifed prefix means service disabled */
  if (!tftp_prefix) {
      tftp_send_error(spt, 2, "Access violation", tp);
      return;
  }

  /* skip header fields */
  k = 0;
  pktlen -= ((uint8_t *)&tp->x.tp_buf[0] - (uint8_t *)tp);

  /* prepend tftp_prefix */
  prefix_len = strlen(tftp_prefix);
  spt->filename = qemu_malloc(prefix_len + TFTP_FILENAME_MAX + 1);
  memcpy(spt->filename, tftp_prefix, prefix_len);

  /* get name */
  req_fname = spt->filename + prefix_len;

  while (1) {
    if (k >= TFTP_FILENAME_MAX || k >= pktlen) {
      tftp_send_error(spt, 2, "Access violation", tp);
      return;
    }
    req_fname[k] = (char)tp->x.tp_buf[k];
    if (req_fname[k++] == '\0') {
      break;
    }
  }

  /* check mode */
  if ((pktlen - k) < 6) {
    tftp_send_error(spt, 2, "Access violation", tp);
    return;
  }

  if (memcmp(&tp->x.tp_buf[k], "octet\0", 6) != 0) {
      tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
      return;
  }

  k += 6; /* skipping octet */

  /* do sanity checks on the filename */
  if (req_fname[0] != '/' || req_fname[strlen(req_fname) - 1] == '/' ||
      strstr(req_fname, "/../")) {
      tftp_send_error(spt, 2, "Access violation", tp);
      return;
  }

  /* check if the file exists */
  if (tftp_read_data(spt, 0, NULL, 0) < 0) {
      tftp_send_error(spt, 1, "File not found", tp);
      return;
  }

  if (tp->x.tp_buf[pktlen - 1] != 0) {
      tftp_send_error(spt, 2, "Access violation", tp);
      return;
  }

  while (k < pktlen) {
      const char *key, *value;

      key = (const char *)&tp->x.tp_buf[k];
      k += strlen(key) + 1;

      if (k >= pktlen) {
	  tftp_send_error(spt, 2, "Access violation", tp);
	  return;
      }

      value = (const char *)&tp->x.tp_buf[k];
      k += strlen(value) + 1;

      if (strcmp(key, "tsize") == 0) {
	  int tsize = atoi(value);
	  struct stat stat_p;

	  if (tsize == 0) {
	      if (stat(spt->filename, &stat_p) == 0)
		  tsize = stat_p.st_size;
	      else {
		  tftp_send_error(spt, 1, "File not found", tp);
		  return;
	      }
	  }

	  tftp_send_oack(spt, "tsize", tsize, tp);
      }
  }

  tftp_send_data(spt, 1, tp);
}

static void tftp_handle_ack(struct tftp_t *tp, int pktlen)
{
  int s;

  s = tftp_session_find(tp);

  if (s < 0) {
    return;
  }

  if (tftp_send_data(&tftp_sessions[s],
		     ntohs(tp->x.tp_data.tp_block_nr) + 1,
		     tp) < 0) {
    return;
  }
}

void tftp_input(struct mbuf *m)
{
  struct tftp_t *tp = (struct tftp_t *)m->m_data;

  switch(ntohs(tp->tp_op)) {
  case TFTP_RRQ:
    tftp_handle_rrq(tp, m->m_len);
    break;

  case TFTP_ACK:
    tftp_handle_ack(tp, m->m_len);
    break;
  }
}
Commit	Line	Data
c7f74643 FB	1	/*
c7f74643 FB	2	* tftp.c - a simple, read-only tftp server for qemu
5fafdf24	3	*
c7f74643	4	* Copyright (c) 2004 Magnus Damm <damm@opensource.se>
5fafdf24	5	*
c7f74643 FB	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:
	12	*
	13	* The above copyright notice and this permission notice shall be included in
	14	* all copies or substantial portions of the Software.
	15	*
	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
	22	* THE SOFTWARE.
	23	*/
	24
	25	#include <slirp.h>
0d62c4cf	26	#include "qemu-common.h"
c7f74643 FB	27
c7f74643 FB	28	struct tftp_session {
a3504c87	29	int in_use;
9367964a	30	char *filename;
3b46e624	31
a3504c87 FB	32	struct in_addr client_ip;
a3504c87 FB	33	u_int16_t client_port;
3b46e624	34
a3504c87	35	int timestamp;
c7f74643 FB	36	};
c7f74643 FB	37
9634d903	38	static struct tftp_session tftp_sessions[TFTP_SESSIONS_MAX];
c7f74643	39
ad196a9d	40	char *tftp_prefix;
c7f74643 FB	41
	42	static void tftp_session_update(struct tftp_session *spt)
	43	{
a3504c87 FB	44	spt->timestamp = curtime;
a3504c87 FB	45	spt->in_use = 1;
c7f74643 FB	46	}
	47
	48	static void tftp_session_terminate(struct tftp_session *spt)
	49	{
9367964a	50	qemu_free(spt->filename);
c7f74643 FB	51	spt->in_use = 0;
	52	}
	53
	54	static int tftp_session_allocate(struct tftp_t *tp)
	55	{
	56	struct tftp_session *spt;
c7f74643 FB	57	int k;
c7f74643 FB	58
c7f74643 FB	59	for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
	60	spt = &tftp_sessions[k];
	61
a3504c87 FB	62	if (!spt->in_use)
a3504c87 FB	63	goto found;
c7f74643 FB	64
c7f74643 FB	65	/* sessions time out after 5 inactive seconds */
9367964a JK	66	if ((int)(curtime - spt->timestamp) > 5000) {
9367964a JK	67	qemu_free(spt->filename);
a3504c87	68	goto found;
9367964a	69	}
c7f74643 FB	70	}
	71
	72	return -1;
	73
	74	found:
	75	memset(spt, 0, sizeof(*spt));
	76	memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
	77	spt->client_port = tp->udp.uh_sport;
	78
	79	tftp_session_update(spt);
	80
	81	return k;
	82	}
	83
	84	static int tftp_session_find(struct tftp_t *tp)
	85	{
	86	struct tftp_session *spt;
	87	int k;
	88
	89	for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
	90	spt = &tftp_sessions[k];
	91
	92	if (spt->in_use) {
	93	if (!memcmp(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip))) {
	94	if (spt->client_port == tp->udp.uh_sport) {
	95	return k;
	96	}
	97	}
	98	}
	99	}
	100
	101	return -1;
	102	}
	103
	104	static int tftp_read_data(struct tftp_session *spt, u_int16_t block_nr,
	105	u_int8_t *buf, int len)
	106	{
	107	int fd;
	108	int bytes_read = 0;
0db1137d	109
9367964a	110	fd = open(spt->filename, O_RDONLY \| O_BINARY);
c7f74643 FB	111
	112	if (fd < 0) {
	113	return -1;
	114	}
	115
	116	if (len) {
	117	lseek(fd, block_nr * 512, SEEK_SET);
	118
	119	bytes_read = read(fd, buf, len);
	120	}
	121
	122	close(fd);
	123
	124	return bytes_read;
	125	}
	126
5fafdf24	127	static int tftp_send_oack(struct tftp_session *spt,
1f697db9 TS	128	const char *key, uint32_t value,
	129	struct tftp_t *recv_tp)
	130	{
	131	struct sockaddr_in saddr, daddr;
	132	struct mbuf *m;
	133	struct tftp_t *tp;
	134	int n = 0;
	135
	136	m = m_get();
	137
	138	if (!m)
	139	return -1;
	140
	141	memset(m->m_data, 0, m->m_size);
	142
9634d903	143	m->m_data += IF_MAXLINKHDR;
1f697db9 TS	144	tp = (void *)m->m_data;
1f697db9 TS	145	m->m_data += sizeof(struct udpiphdr);
3b46e624	146
1f697db9	147	tp->tp_op = htons(TFTP_OACK);
b55266b5 BS	148	n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
	149	key) + 1;
	150	n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
	151	value) + 1;
1f697db9 TS	152
	153	saddr.sin_addr = recv_tp->ip.ip_dst;
	154	saddr.sin_port = recv_tp->udp.uh_dport;
3b46e624	155
1f697db9 TS	156	daddr.sin_addr = spt->client_ip;
	157	daddr.sin_port = spt->client_port;
	158
5fafdf24	159	m->m_len = sizeof(struct tftp_t) - 514 + n -
1f697db9 TS	160	sizeof(struct ip) - sizeof(struct udphdr);
	161	udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
	162
	163	return 0;
	164	}
	165
ef2d54d8 JK	166	static void tftp_send_error(struct tftp_session *spt,
	167	u_int16_t errorcode, const char *msg,
	168	struct tftp_t *recv_tp)
c7f74643 FB	169	{
	170	struct sockaddr_in saddr, daddr;
	171	struct mbuf *m;
	172	struct tftp_t *tp;
	173	int nobytes;
	174
	175	m = m_get();
	176
	177	if (!m) {
ef2d54d8	178	goto out;
c7f74643 FB	179	}
	180
	181	memset(m->m_data, 0, m->m_size);
	182
9634d903	183	m->m_data += IF_MAXLINKHDR;
c7f74643 FB	184	tp = (void *)m->m_data;
c7f74643 FB	185	m->m_data += sizeof(struct udpiphdr);
3b46e624	186
c7f74643 FB	187	tp->tp_op = htons(TFTP_ERROR);
c7f74643 FB	188	tp->x.tp_error.tp_error_code = htons(errorcode);
b55266b5	189	pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg), msg);
c7f74643 FB	190
	191	saddr.sin_addr = recv_tp->ip.ip_dst;
	192	saddr.sin_port = recv_tp->udp.uh_dport;
	193
	194	daddr.sin_addr = spt->client_ip;
	195	daddr.sin_port = spt->client_port;
	196
	197	nobytes = 2;
	198
5fafdf24	199	m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg) -
c7f74643 FB	200	sizeof(struct ip) - sizeof(struct udphdr);
	201
	202	udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
	203
ef2d54d8	204	out:
c7f74643	205	tftp_session_terminate(spt);
c7f74643 FB	206	}
c7f74643 FB	207
5fafdf24	208	static int tftp_send_data(struct tftp_session *spt,
c7f74643 FB	209	u_int16_t block_nr,
	210	struct tftp_t *recv_tp)
	211	{
	212	struct sockaddr_in saddr, daddr;
	213	struct mbuf *m;
	214	struct tftp_t *tp;
	215	int nobytes;
	216
	217	if (block_nr < 1) {
	218	return -1;
	219	}
	220
	221	m = m_get();
	222
	223	if (!m) {
	224	return -1;
	225	}
	226
	227	memset(m->m_data, 0, m->m_size);
	228
9634d903	229	m->m_data += IF_MAXLINKHDR;
c7f74643 FB	230	tp = (void *)m->m_data;
c7f74643 FB	231	m->m_data += sizeof(struct udpiphdr);
3b46e624	232
c7f74643 FB	233	tp->tp_op = htons(TFTP_DATA);
	234	tp->x.tp_data.tp_block_nr = htons(block_nr);
	235
	236	saddr.sin_addr = recv_tp->ip.ip_dst;
	237	saddr.sin_port = recv_tp->udp.uh_dport;
	238
	239	daddr.sin_addr = spt->client_ip;
	240	daddr.sin_port = spt->client_port;
	241
	242	nobytes = tftp_read_data(spt, block_nr - 1, tp->x.tp_data.tp_buf, 512);
	243
	244	if (nobytes < 0) {
	245	m_free(m);
	246
	247	/* send "file not found" error back */
	248
	249	tftp_send_error(spt, 1, "File not found", tp);
	250
	251	return -1;
	252	}
	253
5fafdf24	254	m->m_len = sizeof(struct tftp_t) - (512 - nobytes) -
c7f74643 FB	255	sizeof(struct ip) - sizeof(struct udphdr);
	256
	257	udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
	258
	259	if (nobytes == 512) {
	260	tftp_session_update(spt);
	261	}
	262	else {
	263	tftp_session_terminate(spt);
	264	}
	265
	266	return 0;
	267	}
	268
	269	static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
	270	{
	271	struct tftp_session *spt;
20c24bf2	272	int s, k;
9367964a	273	size_t prefix_len;
20c24bf2	274	char *req_fname;
c7f74643 FB	275
	276	s = tftp_session_allocate(tp);
	277
	278	if (s < 0) {
	279	return;
	280	}
	281
	282	spt = &tftp_sessions[s];
	283
f8e3cbd3 JK	284	/* unspecifed prefix means service disabled */
	285	if (!tftp_prefix) {
	286	tftp_send_error(spt, 2, "Access violation", tp);
	287	return;
	288	}
	289
20c24bf2 JK	290	/* skip header fields */
	291	k = 0;
	292	pktlen -= ((uint8_t )&tp->x.tp_buf[0] - (uint8_t )tp);
c7f74643	293
9367964a JK	294	/* prepend tftp_prefix */
	295	prefix_len = strlen(tftp_prefix);
	296	spt->filename = qemu_malloc(prefix_len + TFTP_FILENAME_MAX + 1);
	297	memcpy(spt->filename, tftp_prefix, prefix_len);
	298
c7f74643	299	/* get name */
9367964a	300	req_fname = spt->filename + prefix_len;
c7f74643	301
20c24bf2 JK	302	while (1) {
	303	if (k >= TFTP_FILENAME_MAX \|\| k >= pktlen) {
	304	tftp_send_error(spt, 2, "Access violation", tp);
c7f74643 FB	305	return;
c7f74643 FB	306	}
20c24bf2 JK	307	req_fname[k] = (char)tp->x.tp_buf[k];
20c24bf2 JK	308	if (req_fname[k++] == '\0') {
c7f74643 FB	309	break;
	310	}
	311	}
3b46e624	312
c7f74643	313	/* check mode */
20c24bf2 JK	314	if ((pktlen - k) < 6) {
20c24bf2 JK	315	tftp_send_error(spt, 2, "Access violation", tp);
c7f74643 FB	316	return;
c7f74643 FB	317	}
3b46e624	318
20c24bf2	319	if (memcmp(&tp->x.tp_buf[k], "octet\0", 6) != 0) {
c7f74643 FB	320	tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
	321	return;
	322	}
	323
1f697db9 TS	324	k += 6; /* skipping octet */
1f697db9 TS	325
c7f74643	326	/* do sanity checks on the filename */
9367964a JK	327	if (req_fname[0] != '/' \|\| req_fname[strlen(req_fname) - 1] == '/' \|\|
9367964a JK	328	strstr(req_fname, "/../")) {
c7f74643 FB	329	tftp_send_error(spt, 2, "Access violation", tp);
	330	return;
	331	}
	332
c7f74643	333	/* check if the file exists */
20c24bf2	334	if (tftp_read_data(spt, 0, NULL, 0) < 0) {
c7f74643 FB	335	tftp_send_error(spt, 1, "File not found", tp);
	336	return;
	337	}
	338
20c24bf2	339	if (tp->x.tp_buf[pktlen - 1] != 0) {
1f697db9 TS	340	tftp_send_error(spt, 2, "Access violation", tp);
	341	return;
	342	}
	343
20c24bf2	344	while (k < pktlen) {
1f697db9 TS	345	const char key, value;
1f697db9 TS	346
20c24bf2	347	key = (const char *)&tp->x.tp_buf[k];
1f697db9 TS	348	k += strlen(key) + 1;
1f697db9 TS	349
20c24bf2	350	if (k >= pktlen) {
1f697db9 TS	351	tftp_send_error(spt, 2, "Access violation", tp);
	352	return;
	353	}
	354
20c24bf2	355	value = (const char *)&tp->x.tp_buf[k];
1f697db9 TS	356	k += strlen(value) + 1;
	357
	358	if (strcmp(key, "tsize") == 0) {
	359	int tsize = atoi(value);
	360	struct stat stat_p;
	361
f8e3cbd3	362	if (tsize == 0) {
9367964a	363	if (stat(spt->filename, &stat_p) == 0)
1f697db9 TS	364	tsize = stat_p.st_size;
	365	else {
	366	tftp_send_error(spt, 1, "File not found", tp);
	367	return;
	368	}
	369	}
	370
	371	tftp_send_oack(spt, "tsize", tsize, tp);
	372	}
	373	}
	374
c7f74643 FB	375	tftp_send_data(spt, 1, tp);
	376	}
	377
	378	static void tftp_handle_ack(struct tftp_t *tp, int pktlen)
	379	{
	380	int s;
	381
	382	s = tftp_session_find(tp);
	383
	384	if (s < 0) {
	385	return;
	386	}
	387
5fafdf24 TS	388	if (tftp_send_data(&tftp_sessions[s],
5fafdf24 TS	389	ntohs(tp->x.tp_data.tp_block_nr) + 1,
c7f74643 FB	390	tp) < 0) {
	391	return;
	392	}
	393	}
	394
	395	void tftp_input(struct mbuf *m)
	396	{
	397	struct tftp_t tp = (struct tftp_t )m->m_data;
	398
	399	switch(ntohs(tp->tp_op)) {
	400	case TFTP_RRQ:
	401	tftp_handle_rrq(tp, m->m_len);
	402	break;
	403
	404	case TFTP_ACK:
	405	tftp_handle_ack(tp, m->m_len);
	406	break;
	407	}
	408	}