[mirror_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>

struct tftp_session {
    int in_use;
    unsigned char filename[TFTP_FILENAME_MAX];

    struct in_addr client_ip;
    u_int16_t client_port;

    int timestamp;
};

struct tftp_session tftp_sessions[TFTP_SESSIONS_MAX];

const 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)
{
  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)
        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;
  char buffer[1024];
  int n;

  n = snprintf(buffer, sizeof(buffer), "%s/%s",
	       tftp_prefix, spt->filename);
  if (n >= sizeof(buffer))
    return -1;

  fd = open(buffer, 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 += sprintf(tp->x.tp_buf + n, "%s", key) + 1;
    n += sprintf(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 int 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) {
    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_ERROR);
  tp->x.tp_error.tp_error_code = htons(errorcode);
  strcpy(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);

  tftp_session_terminate(spt);

  return 0;
}

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, n;
  u_int8_t *src, *dst;

  s = tftp_session_allocate(tp);

  if (s < 0) {
    return;
  }

  spt = &tftp_sessions[s];

  src = tp->x.tp_buf;
  dst = spt->filename;
  n = pktlen - ((uint8_t *)&tp->x.tp_buf[0] - (uint8_t *)tp);

  /* get name */

  for (k = 0; k < n; k++) {
    if (k < TFTP_FILENAME_MAX) {
      dst[k] = src[k];
    }
    else {
      return;
    }

    if (src[k] == '\0') {
      break;
    }
  }

  if (k >= n) {
    return;
  }

  k++;

  /* check mode */
  if ((n - k) < 6) {
    return;
  }

  if (memcmp(&src[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 ((spt->filename[0] != '/')
      || (spt->filename[strlen(spt->filename) - 1] == '/')
      ||  strstr(spt->filename, "/../")) {
      tftp_send_error(spt, 2, "Access violation", tp);
      return;
  }

  /* only allow exported prefixes */

  if (!tftp_prefix) {
      tftp_send_error(spt, 2, "Access violation", tp);
      return;
  }

  /* check if the file exists */

  if (tftp_read_data(spt, 0, spt->filename, 0) < 0) {
      tftp_send_error(spt, 1, "File not found", tp);
      return;
  }

  if (src[n - 1] != 0) {
      tftp_send_error(spt, 2, "Access violation", tp);
      return;
  }

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

      key = src + k;
      k += strlen(key) + 1;

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

      value = src + k;
      k += strlen(value) + 1;

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

	  if (tsize == 0 && tftp_prefix) {
	      char buffer[1024];
	      int len;

	      len = snprintf(buffer, sizeof(buffer), "%s/%s",
			     tftp_prefix, spt->filename);

	      if (stat(buffer, &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>
	26
	27	struct tftp_session {
a3504c87 FB	28	int in_use;
a3504c87 FB	29	unsigned char filename[TFTP_FILENAME_MAX];
3b46e624	30
a3504c87 FB	31	struct in_addr client_ip;
a3504c87 FB	32	u_int16_t client_port;
3b46e624	33
a3504c87	34	int timestamp;
c7f74643 FB	35	};
	36
	37	struct tftp_session tftp_sessions[TFTP_SESSIONS_MAX];
	38
9bf05444	39	const char *tftp_prefix;
c7f74643 FB	40
	41	static void tftp_session_update(struct tftp_session *spt)
	42	{
a3504c87 FB	43	spt->timestamp = curtime;
a3504c87 FB	44	spt->in_use = 1;
c7f74643 FB	45	}
	46
	47	static void tftp_session_terminate(struct tftp_session *spt)
	48	{
	49	spt->in_use = 0;
	50	}
	51
	52	static int tftp_session_allocate(struct tftp_t *tp)
	53	{
	54	struct tftp_session *spt;
c7f74643 FB	55	int k;
c7f74643 FB	56
c7f74643 FB	57	for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
	58	spt = &tftp_sessions[k];
	59
a3504c87 FB	60	if (!spt->in_use)
a3504c87 FB	61	goto found;
c7f74643 FB	62
c7f74643 FB	63	/* sessions time out after 5 inactive seconds */
a3504c87 FB	64	if ((int)(curtime - spt->timestamp) > 5000)
a3504c87 FB	65	goto found;
c7f74643 FB	66	}
	67
	68	return -1;
	69
	70	found:
	71	memset(spt, 0, sizeof(*spt));
	72	memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
	73	spt->client_port = tp->udp.uh_sport;
	74
	75	tftp_session_update(spt);
	76
	77	return k;
	78	}
	79
	80	static int tftp_session_find(struct tftp_t *tp)
	81	{
	82	struct tftp_session *spt;
	83	int k;
	84
	85	for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
	86	spt = &tftp_sessions[k];
	87
	88	if (spt->in_use) {
	89	if (!memcmp(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip))) {
	90	if (spt->client_port == tp->udp.uh_sport) {
	91	return k;
	92	}
	93	}
	94	}
	95	}
	96
	97	return -1;
	98	}
	99
	100	static int tftp_read_data(struct tftp_session *spt, u_int16_t block_nr,
	101	u_int8_t *buf, int len)
	102	{
	103	int fd;
	104	int bytes_read = 0;
0db1137d TS	105	char buffer[1024];
0db1137d TS	106	int n;
c7f74643	107
0db1137d TS	108	n = snprintf(buffer, sizeof(buffer), "%s/%s",
	109	tftp_prefix, spt->filename);
	110	if (n >= sizeof(buffer))
	111	return -1;
	112
	113	fd = open(buffer, O_RDONLY \| O_BINARY);
c7f74643 FB	114
	115	if (fd < 0) {
	116	return -1;
	117	}
	118
	119	if (len) {
	120	lseek(fd, block_nr * 512, SEEK_SET);
	121
	122	bytes_read = read(fd, buf, len);
	123	}
	124
	125	close(fd);
	126
	127	return bytes_read;
	128	}
	129
5fafdf24	130	static int tftp_send_oack(struct tftp_session *spt,
1f697db9 TS	131	const char *key, uint32_t value,
	132	struct tftp_t *recv_tp)
	133	{
	134	struct sockaddr_in saddr, daddr;
	135	struct mbuf *m;
	136	struct tftp_t *tp;
	137	int n = 0;
	138
	139	m = m_get();
	140
	141	if (!m)
	142	return -1;
	143
	144	memset(m->m_data, 0, m->m_size);
	145
	146	m->m_data += if_maxlinkhdr;
	147	tp = (void *)m->m_data;
	148	m->m_data += sizeof(struct udpiphdr);
3b46e624	149
1f697db9 TS	150	tp->tp_op = htons(TFTP_OACK);
	151	n += sprintf(tp->x.tp_buf + n, "%s", key) + 1;
	152	n += sprintf(tp->x.tp_buf + n, "%u", value) + 1;
	153
	154	saddr.sin_addr = recv_tp->ip.ip_dst;
	155	saddr.sin_port = recv_tp->udp.uh_dport;
3b46e624	156
1f697db9 TS	157	daddr.sin_addr = spt->client_ip;
	158	daddr.sin_port = spt->client_port;
	159
5fafdf24	160	m->m_len = sizeof(struct tftp_t) - 514 + n -
1f697db9 TS	161	sizeof(struct ip) - sizeof(struct udphdr);
	162	udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
	163
	164	return 0;
	165	}
	166
	167
	168
5fafdf24	169	static int tftp_send_error(struct tftp_session *spt,
c7f74643 FB	170	u_int16_t errorcode, const char *msg,
	171	struct tftp_t *recv_tp)
	172	{
	173	struct sockaddr_in saddr, daddr;
	174	struct mbuf *m;
	175	struct tftp_t *tp;
	176	int nobytes;
	177
	178	m = m_get();
	179
	180	if (!m) {
	181	return -1;
	182	}
	183
	184	memset(m->m_data, 0, m->m_size);
	185
	186	m->m_data += if_maxlinkhdr;
	187	tp = (void *)m->m_data;
	188	m->m_data += sizeof(struct udpiphdr);
3b46e624	189
c7f74643 FB	190	tp->tp_op = htons(TFTP_ERROR);
	191	tp->x.tp_error.tp_error_code = htons(errorcode);
	192	strcpy(tp->x.tp_error.tp_msg, msg);
	193
	194	saddr.sin_addr = recv_tp->ip.ip_dst;
	195	saddr.sin_port = recv_tp->udp.uh_dport;
	196
	197	daddr.sin_addr = spt->client_ip;
	198	daddr.sin_port = spt->client_port;
	199
	200	nobytes = 2;
	201
5fafdf24	202	m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg) -
c7f74643 FB	203	sizeof(struct ip) - sizeof(struct udphdr);
	204
	205	udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
	206
	207	tftp_session_terminate(spt);
	208
	209	return 0;
	210	}
	211
5fafdf24	212	static int tftp_send_data(struct tftp_session *spt,
c7f74643 FB	213	u_int16_t block_nr,
	214	struct tftp_t *recv_tp)
	215	{
	216	struct sockaddr_in saddr, daddr;
	217	struct mbuf *m;
	218	struct tftp_t *tp;
	219	int nobytes;
	220
	221	if (block_nr < 1) {
	222	return -1;
	223	}
	224
	225	m = m_get();
	226
	227	if (!m) {
	228	return -1;
	229	}
	230
	231	memset(m->m_data, 0, m->m_size);
	232
	233	m->m_data += if_maxlinkhdr;
	234	tp = (void *)m->m_data;
	235	m->m_data += sizeof(struct udpiphdr);
3b46e624	236
c7f74643 FB	237	tp->tp_op = htons(TFTP_DATA);
	238	tp->x.tp_data.tp_block_nr = htons(block_nr);
	239
	240	saddr.sin_addr = recv_tp->ip.ip_dst;
	241	saddr.sin_port = recv_tp->udp.uh_dport;
	242
	243	daddr.sin_addr = spt->client_ip;
	244	daddr.sin_port = spt->client_port;
	245
	246	nobytes = tftp_read_data(spt, block_nr - 1, tp->x.tp_data.tp_buf, 512);
	247
	248	if (nobytes < 0) {
	249	m_free(m);
	250
	251	/* send "file not found" error back */
	252
	253	tftp_send_error(spt, 1, "File not found", tp);
	254
	255	return -1;
	256	}
	257
5fafdf24	258	m->m_len = sizeof(struct tftp_t) - (512 - nobytes) -
c7f74643 FB	259	sizeof(struct ip) - sizeof(struct udphdr);
	260
	261	udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
	262
	263	if (nobytes == 512) {
	264	tftp_session_update(spt);
	265	}
	266	else {
	267	tftp_session_terminate(spt);
	268	}
	269
	270	return 0;
	271	}
	272
	273	static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
	274	{
	275	struct tftp_session *spt;
	276	int s, k, n;
	277	u_int8_t src, dst;
	278
	279	s = tftp_session_allocate(tp);
	280
	281	if (s < 0) {
	282	return;
	283	}
	284
	285	spt = &tftp_sessions[s];
	286
	287	src = tp->x.tp_buf;
	288	dst = spt->filename;
	289	n = pktlen - ((uint8_t )&tp->x.tp_buf[0] - (uint8_t )tp);
	290
	291	/* get name */
	292
	293	for (k = 0; k < n; k++) {
	294	if (k < TFTP_FILENAME_MAX) {
	295	dst[k] = src[k];
	296	}
	297	else {
	298	return;
	299	}
3b46e624	300
c7f74643 FB	301	if (src[k] == '\0') {
	302	break;
	303	}
	304	}
3b46e624	305
c7f74643 FB	306	if (k >= n) {
	307	return;
	308	}
3b46e624	309
c7f74643	310	k++;
3b46e624	311
c7f74643 FB	312	/* check mode */
	313	if ((n - k) < 6) {
	314	return;
	315	}
3b46e624	316
c7f74643 FB	317	if (memcmp(&src[k], "octet\0", 6) != 0) {
	318	tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
	319	return;
	320	}
	321
1f697db9 TS	322	k += 6; /* skipping octet */
1f697db9 TS	323
c7f74643 FB	324	/* do sanity checks on the filename */
	325
	326	if ((spt->filename[0] != '/')
	327	\|\| (spt->filename[strlen(spt->filename) - 1] == '/')
	328	\|\| strstr(spt->filename, "/../")) {
	329	tftp_send_error(spt, 2, "Access violation", tp);
	330	return;
	331	}
	332
	333	/* only allow exported prefixes */
	334
0db1137d	335	if (!tftp_prefix) {
c7f74643 FB	336	tftp_send_error(spt, 2, "Access violation", tp);
	337	return;
	338	}
	339
	340	/* check if the file exists */
3b46e624	341
c7f74643 FB	342	if (tftp_read_data(spt, 0, spt->filename, 0) < 0) {
	343	tftp_send_error(spt, 1, "File not found", tp);
	344	return;
	345	}
	346
1f697db9 TS	347	if (src[n - 1] != 0) {
	348	tftp_send_error(spt, 2, "Access violation", tp);
	349	return;
	350	}
	351
	352	while (k < n) {
	353	const char key, value;
	354
	355	key = src + k;
	356	k += strlen(key) + 1;
	357
	358	if (k >= n) {
	359	tftp_send_error(spt, 2, "Access violation", tp);
	360	return;
	361	}
	362
	363	value = src + k;
	364	k += strlen(value) + 1;
	365
	366	if (strcmp(key, "tsize") == 0) {
	367	int tsize = atoi(value);
	368	struct stat stat_p;
	369
	370	if (tsize == 0 && tftp_prefix) {
	371	char buffer[1024];
	372	int len;
	373
	374	len = snprintf(buffer, sizeof(buffer), "%s/%s",
	375	tftp_prefix, spt->filename);
	376
	377	if (stat(buffer, &stat_p) == 0)
	378	tsize = stat_p.st_size;
	379	else {
	380	tftp_send_error(spt, 1, "File not found", tp);
	381	return;
	382	}
	383	}
	384
	385	tftp_send_oack(spt, "tsize", tsize, tp);
	386	}
	387	}
	388
c7f74643 FB	389	tftp_send_data(spt, 1, tp);
	390	}
	391
	392	static void tftp_handle_ack(struct tftp_t *tp, int pktlen)
	393	{
	394	int s;
	395
	396	s = tftp_session_find(tp);
	397
	398	if (s < 0) {
	399	return;
	400	}
	401
5fafdf24 TS	402	if (tftp_send_data(&tftp_sessions[s],
5fafdf24 TS	403	ntohs(tp->x.tp_data.tp_block_nr) + 1,
c7f74643 FB	404	tp) < 0) {
	405	return;
	406	}
	407	}
	408
	409	void tftp_input(struct mbuf *m)
	410	{
	411	struct tftp_t tp = (struct tftp_t )m->m_data;
	412
	413	switch(ntohs(tp->tp_op)) {
	414	case TFTP_RRQ:
	415	tftp_handle_rrq(tp, m->m_len);
	416	break;
	417
	418	case TFTP_ACK:
	419	tftp_handle_ack(tp, m->m_len);
	420	break;
	421	}
	422	}