[qemu.git] / slirp / tftp.c

/*
 * tftp.c - a simple, read-only tftp server for qemu
 *
 * Copyright (c) 2004 Magnus Damm <[email protected]>
 *
 * 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"

static inline int tftp_session_in_use(struct tftp_session *spt)
{
    return (spt->slirp != NULL);
}

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

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

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

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

    if (!tftp_session_in_use(spt))
        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;
  spt->slirp = slirp;

  tftp_session_update(spt);

  return k;
}

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

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

    if (tftp_session_in_use(spt)) {
      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, uint16_t block_nr,
                          uint8_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(spt->slirp);

    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,
                            uint16_t errorcode, const char *msg,
                            struct tftp_t *recv_tp)
{
  struct sockaddr_in saddr, daddr;
  struct mbuf *m;
  struct tftp_t *tp;

  m = m_get(spt->slirp);

  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;

  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,
                          uint16_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(spt->slirp);

  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(Slirp *slirp, struct tftp_t *tp, int pktlen)
{
  struct tftp_session *spt;
  int s, k;
  size_t prefix_len;
  char *req_fname;

  /* check if a session already exists and if so terminate it */
  s = tftp_session_find(slirp, tp);
  if (s >= 0) {
    tftp_session_terminate(&slirp->tftp_sessions[s]);
  }

  s = tftp_session_allocate(slirp, tp);

  if (s < 0) {
    return;
  }

  spt = &slirp->tftp_sessions[s];

  /* unspecifed prefix means service disabled */
  if (!slirp->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(slirp->tftp_prefix);
  spt->filename = qemu_malloc(prefix_len + TFTP_FILENAME_MAX + 2);
  memcpy(spt->filename, slirp->tftp_prefix, prefix_len);
  spt->filename[prefix_len] = '/';

  /* get name */
  req_fname = spt->filename + prefix_len + 1;

  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 (!strncmp(req_fname, "../", 3) ||
      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);
	  return;
      }
  }

  tftp_send_data(spt, 1, tp);
}

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

  s = tftp_session_find(slirp, tp);

  if (s < 0) {
    return;
  }

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

static void tftp_handle_error(Slirp *slirp, struct tftp_t *tp, int pktlen)
{
  int s;

  s = tftp_session_find(slirp, tp);

  if (s < 0) {
    return;
  }

  tftp_session_terminate(&slirp->tftp_sessions[s]);
}

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(m->slirp, tp, m->m_len);
    break;

  case TFTP_ACK:
    tftp_handle_ack(m->slirp, tp, m->m_len);
    break;

  case TFTP_ERROR:
    tftp_handle_error(m->slirp, 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 <[email protected]>
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	27
460fec67 JK	28	static inline int tftp_session_in_use(struct tftp_session *spt)
	29	{
	30	return (spt->slirp != NULL);
	31	}
c7f74643	32
460fec67	33	static inline void tftp_session_update(struct tftp_session *spt)
c7f74643	34	{
a3504c87	35	spt->timestamp = curtime;
c7f74643 FB	36	}
	37
	38	static void tftp_session_terminate(struct tftp_session *spt)
	39	{
460fec67 JK	40	qemu_free(spt->filename);
460fec67 JK	41	spt->slirp = NULL;
c7f74643 FB	42	}
c7f74643 FB	43
460fec67	44	static int tftp_session_allocate(Slirp slirp, struct tftp_t tp)
c7f74643 FB	45	{
c7f74643 FB	46	struct tftp_session *spt;
c7f74643 FB	47	int k;
c7f74643 FB	48
c7f74643	49	for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
460fec67	50	spt = &slirp->tftp_sessions[k];
c7f74643	51
460fec67	52	if (!tftp_session_in_use(spt))
a3504c87	53	goto found;
c7f74643 FB	54
c7f74643 FB	55	/* sessions time out after 5 inactive seconds */
9367964a JK	56	if ((int)(curtime - spt->timestamp) > 5000) {
9367964a JK	57	qemu_free(spt->filename);
a3504c87	58	goto found;
9367964a	59	}
c7f74643 FB	60	}
	61
	62	return -1;
	63
	64	found:
	65	memset(spt, 0, sizeof(*spt));
	66	memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
	67	spt->client_port = tp->udp.uh_sport;
460fec67	68	spt->slirp = slirp;
c7f74643 FB	69
	70	tftp_session_update(spt);
	71
	72	return k;
	73	}
	74
460fec67	75	static int tftp_session_find(Slirp slirp, struct tftp_t tp)
c7f74643 FB	76	{
	77	struct tftp_session *spt;
	78	int k;
	79
	80	for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
460fec67	81	spt = &slirp->tftp_sessions[k];
c7f74643	82
460fec67	83	if (tftp_session_in_use(spt)) {
c7f74643 FB	84	if (!memcmp(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip))) {
	85	if (spt->client_port == tp->udp.uh_sport) {
	86	return k;
	87	}
	88	}
	89	}
	90	}
	91
	92	return -1;
	93	}
	94
b6dce92e SW	95	static int tftp_read_data(struct tftp_session *spt, uint16_t block_nr,
b6dce92e SW	96	uint8_t *buf, int len)
c7f74643 FB	97	{
	98	int fd;
	99	int bytes_read = 0;
0db1137d	100
9367964a	101	fd = open(spt->filename, O_RDONLY \| O_BINARY);
c7f74643 FB	102
	103	if (fd < 0) {
	104	return -1;
	105	}
	106
	107	if (len) {
	108	lseek(fd, block_nr * 512, SEEK_SET);
	109
	110	bytes_read = read(fd, buf, len);
	111	}
	112
	113	close(fd);
	114
	115	return bytes_read;
	116	}
	117
5fafdf24	118	static int tftp_send_oack(struct tftp_session *spt,
1f697db9 TS	119	const char *key, uint32_t value,
	120	struct tftp_t *recv_tp)
	121	{
	122	struct sockaddr_in saddr, daddr;
	123	struct mbuf *m;
	124	struct tftp_t *tp;
	125	int n = 0;
	126
460fec67	127	m = m_get(spt->slirp);
1f697db9 TS	128
	129	if (!m)
	130	return -1;
	131
	132	memset(m->m_data, 0, m->m_size);
	133
9634d903	134	m->m_data += IF_MAXLINKHDR;
1f697db9 TS	135	tp = (void *)m->m_data;
1f697db9 TS	136	m->m_data += sizeof(struct udpiphdr);
3b46e624	137
1f697db9	138	tp->tp_op = htons(TFTP_OACK);
b55266b5 BS	139	n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
	140	key) + 1;
	141	n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
	142	value) + 1;
1f697db9 TS	143
	144	saddr.sin_addr = recv_tp->ip.ip_dst;
	145	saddr.sin_port = recv_tp->udp.uh_dport;
3b46e624	146
1f697db9 TS	147	daddr.sin_addr = spt->client_ip;
	148	daddr.sin_port = spt->client_port;
	149
5fafdf24	150	m->m_len = sizeof(struct tftp_t) - 514 + n -
1f697db9 TS	151	sizeof(struct ip) - sizeof(struct udphdr);
	152	udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
	153
	154	return 0;
	155	}
	156
ef2d54d8	157	static void tftp_send_error(struct tftp_session *spt,
b6dce92e	158	uint16_t errorcode, const char *msg,
ef2d54d8	159	struct tftp_t *recv_tp)
c7f74643 FB	160	{
	161	struct sockaddr_in saddr, daddr;
	162	struct mbuf *m;
	163	struct tftp_t *tp;
c7f74643	164
460fec67	165	m = m_get(spt->slirp);
c7f74643 FB	166
c7f74643 FB	167	if (!m) {
ef2d54d8	168	goto out;
c7f74643 FB	169	}
	170
	171	memset(m->m_data, 0, m->m_size);
	172
9634d903	173	m->m_data += IF_MAXLINKHDR;
c7f74643 FB	174	tp = (void *)m->m_data;
c7f74643 FB	175	m->m_data += sizeof(struct udpiphdr);
3b46e624	176
c7f74643 FB	177	tp->tp_op = htons(TFTP_ERROR);
c7f74643 FB	178	tp->x.tp_error.tp_error_code = htons(errorcode);
b55266b5	179	pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg), msg);
c7f74643 FB	180
	181	saddr.sin_addr = recv_tp->ip.ip_dst;
	182	saddr.sin_port = recv_tp->udp.uh_dport;
	183
	184	daddr.sin_addr = spt->client_ip;
	185	daddr.sin_port = spt->client_port;
	186
5fafdf24	187	m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg) -
c7f74643 FB	188	sizeof(struct ip) - sizeof(struct udphdr);
	189
	190	udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
	191
ef2d54d8	192	out:
c7f74643	193	tftp_session_terminate(spt);
c7f74643 FB	194	}
c7f74643 FB	195
5fafdf24	196	static int tftp_send_data(struct tftp_session *spt,
b6dce92e	197	uint16_t block_nr,
c7f74643 FB	198	struct tftp_t *recv_tp)
	199	{
	200	struct sockaddr_in saddr, daddr;
	201	struct mbuf *m;
	202	struct tftp_t *tp;
	203	int nobytes;
	204
	205	if (block_nr < 1) {
	206	return -1;
	207	}
	208
460fec67	209	m = m_get(spt->slirp);
c7f74643 FB	210
	211	if (!m) {
	212	return -1;
	213	}
	214
	215	memset(m->m_data, 0, m->m_size);
	216
9634d903	217	m->m_data += IF_MAXLINKHDR;
c7f74643 FB	218	tp = (void *)m->m_data;
c7f74643 FB	219	m->m_data += sizeof(struct udpiphdr);
3b46e624	220
c7f74643 FB	221	tp->tp_op = htons(TFTP_DATA);
	222	tp->x.tp_data.tp_block_nr = htons(block_nr);
	223
	224	saddr.sin_addr = recv_tp->ip.ip_dst;
	225	saddr.sin_port = recv_tp->udp.uh_dport;
	226
	227	daddr.sin_addr = spt->client_ip;
	228	daddr.sin_port = spt->client_port;
	229
	230	nobytes = tftp_read_data(spt, block_nr - 1, tp->x.tp_data.tp_buf, 512);
	231
	232	if (nobytes < 0) {
	233	m_free(m);
	234
	235	/* send "file not found" error back */
	236
	237	tftp_send_error(spt, 1, "File not found", tp);
	238
	239	return -1;
	240	}
	241
5fafdf24	242	m->m_len = sizeof(struct tftp_t) - (512 - nobytes) -
c7f74643 FB	243	sizeof(struct ip) - sizeof(struct udphdr);
	244
	245	udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
	246
	247	if (nobytes == 512) {
	248	tftp_session_update(spt);
	249	}
	250	else {
	251	tftp_session_terminate(spt);
	252	}
	253
	254	return 0;
	255	}
	256
460fec67	257	static void tftp_handle_rrq(Slirp slirp, struct tftp_t tp, int pktlen)
c7f74643 FB	258	{
c7f74643 FB	259	struct tftp_session *spt;
20c24bf2	260	int s, k;
9367964a	261	size_t prefix_len;
20c24bf2	262	char *req_fname;
c7f74643	263
bfe4e172 TH	264	/* check if a session already exists and if so terminate it */
	265	s = tftp_session_find(slirp, tp);
	266	if (s >= 0) {
	267	tftp_session_terminate(&slirp->tftp_sessions[s]);
	268	}
	269
460fec67	270	s = tftp_session_allocate(slirp, tp);
c7f74643 FB	271
	272	if (s < 0) {
	273	return;
	274	}
	275
460fec67	276	spt = &slirp->tftp_sessions[s];
c7f74643	277
f8e3cbd3	278	/* unspecifed prefix means service disabled */
460fec67	279	if (!slirp->tftp_prefix) {
f8e3cbd3 JK	280	tftp_send_error(spt, 2, "Access violation", tp);
	281	return;
	282	}
	283
20c24bf2 JK	284	/* skip header fields */
	285	k = 0;
	286	pktlen -= ((uint8_t )&tp->x.tp_buf[0] - (uint8_t )tp);
c7f74643	287
9367964a	288	/* prepend tftp_prefix */
460fec67	289	prefix_len = strlen(slirp->tftp_prefix);
74efd61a	290	spt->filename = qemu_malloc(prefix_len + TFTP_FILENAME_MAX + 2);
460fec67	291	memcpy(spt->filename, slirp->tftp_prefix, prefix_len);
74efd61a	292	spt->filename[prefix_len] = '/';
9367964a	293
c7f74643	294	/* get name */
74efd61a	295	req_fname = spt->filename + prefix_len + 1;
c7f74643	296
20c24bf2 JK	297	while (1) {
	298	if (k >= TFTP_FILENAME_MAX \|\| k >= pktlen) {
	299	tftp_send_error(spt, 2, "Access violation", tp);
c7f74643 FB	300	return;
c7f74643 FB	301	}
20c24bf2 JK	302	req_fname[k] = (char)tp->x.tp_buf[k];
20c24bf2 JK	303	if (req_fname[k++] == '\0') {
c7f74643 FB	304	break;
	305	}
	306	}
3b46e624	307
c7f74643	308	/* check mode */
20c24bf2 JK	309	if ((pktlen - k) < 6) {
20c24bf2 JK	310	tftp_send_error(spt, 2, "Access violation", tp);
c7f74643 FB	311	return;
c7f74643 FB	312	}
3b46e624	313
20c24bf2	314	if (memcmp(&tp->x.tp_buf[k], "octet\0", 6) != 0) {
c7f74643 FB	315	tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
	316	return;
	317	}
	318
1f697db9 TS	319	k += 6; /* skipping octet */
1f697db9 TS	320
c7f74643	321	/* do sanity checks on the filename */
74efd61a JK	322	if (!strncmp(req_fname, "../", 3) \|\|
74efd61a JK	323	req_fname[strlen(req_fname) - 1] == '/' \|\|
9367964a	324	strstr(req_fname, "/../")) {
c7f74643 FB	325	tftp_send_error(spt, 2, "Access violation", tp);
	326	return;
	327	}
	328
c7f74643	329	/* check if the file exists */
20c24bf2	330	if (tftp_read_data(spt, 0, NULL, 0) < 0) {
c7f74643 FB	331	tftp_send_error(spt, 1, "File not found", tp);
	332	return;
	333	}
	334
20c24bf2	335	if (tp->x.tp_buf[pktlen - 1] != 0) {
1f697db9 TS	336	tftp_send_error(spt, 2, "Access violation", tp);
	337	return;
	338	}
	339
20c24bf2	340	while (k < pktlen) {
1f697db9 TS	341	const char key, value;
1f697db9 TS	342
20c24bf2	343	key = (const char *)&tp->x.tp_buf[k];
1f697db9 TS	344	k += strlen(key) + 1;
1f697db9 TS	345
20c24bf2	346	if (k >= pktlen) {
1f697db9 TS	347	tftp_send_error(spt, 2, "Access violation", tp);
	348	return;
	349	}
	350
20c24bf2	351	value = (const char *)&tp->x.tp_buf[k];
1f697db9 TS	352	k += strlen(value) + 1;
	353
	354	if (strcmp(key, "tsize") == 0) {
	355	int tsize = atoi(value);
	356	struct stat stat_p;
	357
f8e3cbd3	358	if (tsize == 0) {
9367964a	359	if (stat(spt->filename, &stat_p) == 0)
1f697db9 TS	360	tsize = stat_p.st_size;
	361	else {
	362	tftp_send_error(spt, 1, "File not found", tp);
	363	return;
	364	}
	365	}
	366
	367	tftp_send_oack(spt, "tsize", tsize, tp);
1cb1a66a	368	return;
1f697db9 TS	369	}
	370	}
	371
c7f74643 FB	372	tftp_send_data(spt, 1, tp);
	373	}
	374
460fec67	375	static void tftp_handle_ack(Slirp slirp, struct tftp_t tp, int pktlen)
c7f74643 FB	376	{
	377	int s;
	378
460fec67	379	s = tftp_session_find(slirp, tp);
c7f74643 FB	380
	381	if (s < 0) {
	382	return;
	383	}
	384
460fec67	385	if (tftp_send_data(&slirp->tftp_sessions[s],
5fafdf24	386	ntohs(tp->x.tp_data.tp_block_nr) + 1,
c7f74643 FB	387	tp) < 0) {
	388	return;
	389	}
	390	}
	391
bfe4e172 TH	392	static void tftp_handle_error(Slirp slirp, struct tftp_t tp, int pktlen)
	393	{
	394	int s;
	395
	396	s = tftp_session_find(slirp, tp);
	397
	398	if (s < 0) {
	399	return;
	400	}
	401
	402	tftp_session_terminate(&slirp->tftp_sessions[s]);
	403	}
	404
c7f74643 FB	405	void tftp_input(struct mbuf *m)
	406	{
	407	struct tftp_t tp = (struct tftp_t )m->m_data;
	408
	409	switch(ntohs(tp->tp_op)) {
	410	case TFTP_RRQ:
460fec67	411	tftp_handle_rrq(m->slirp, tp, m->m_len);
c7f74643 FB	412	break;
	413
	414	case TFTP_ACK:
460fec67	415	tftp_handle_ack(m->slirp, tp, m->m_len);
c7f74643	416	break;
bfe4e172 TH	417
	418	case TFTP_ERROR:
	419	tftp_handle_error(m->slirp, tp, m->m_len);
	420	break;
c7f74643 FB	421	}
c7f74643 FB	422	}