[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)
{
    if (spt->fd >= 0) {
        close(spt->fd);
        spt->fd = -1;
    }
    g_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) {
        tftp_session_terminate(spt);
        goto found;
    }
  }

  return -1;

 found:
  memset(spt, 0, sizeof(*spt));
  memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
  spt->fd = -1;
  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, uint32_t block_nr,
                          uint8_t *buf, int len)
{
    int bytes_read = 0;

    if (spt->fd < 0) {
        spt->fd = open(spt->filename, O_RDONLY | O_BINARY);
    }

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

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

        bytes_read = read(spt->fd, buf, len);
    }

    return bytes_read;
}

static int tftp_send_oack(struct tftp_session *spt,
                          const char *keys[], uint32_t values[], int nb,
                          struct tftp_t *recv_tp)
{
    struct sockaddr_in saddr, daddr;
    struct mbuf *m;
    struct tftp_t *tp;
    int i, 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);
    for (i = 0; i < nb; i++) {
        n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
                      keys[i]) + 1;
        n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
                      values[i]) + 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 void tftp_send_next_block(struct tftp_session *spt,
                                 struct tftp_t *recv_tp)
{
  struct sockaddr_in saddr, daddr;
  struct mbuf *m;
  struct tftp_t *tp;
  int nobytes;

  m = m_get(spt->slirp);

  if (!m) {
    return;
  }

  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((spt->block_nr + 1) & 0xffff);

  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, spt->block_nr, 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;
  }

  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);
  }

  spt->block_nr++;
}

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;
  const char *option_name[2];
  uint32_t option_value[2];
  int nb_options = 0;

  /* 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 -= offsetof(struct tftp_t, x.tp_buf);

  /* prepend tftp_prefix */
  prefix_len = strlen(slirp->tftp_prefix);
  spt->filename = g_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] = 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 (strcasecmp(&tp->x.tp_buf[k], "octet") != 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 && nb_options < ARRAY_SIZE(option_name)) {
      const char *key, *value;

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

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

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

      if (strcasecmp(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;
	      }
	  }

          option_name[nb_options] = "tsize";
          option_value[nb_options] = tsize;
          nb_options++;
      } else if (strcasecmp(key, "blksize") == 0) {
          int blksize = atoi(value);

          /* If blksize option is bigger than what we will
           * emit, accept the option with our packet size.
           * Otherwise, simply do as we didn't see the option.
           */
          if (blksize >= 512) {
              option_name[nb_options] = "blksize";
              option_value[nb_options] = 512;
              nb_options++;
          }
      }
  }

  if (nb_options > 0) {
      assert(nb_options <= ARRAY_SIZE(option_name));
      tftp_send_oack(spt, option_name, option_value, nb_options, tp);
      return;
  }

  spt->block_nr = 0;
  tftp_send_next_block(spt, 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;
  }

  tftp_send_next_block(&slirp->tftp_sessions[s], tp);
}

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	{
78be0566 HP	40	if (spt->fd >= 0) {
	41	close(spt->fd);
	42	spt->fd = -1;
	43	}
7267c094	44	g_free(spt->filename);
460fec67	45	spt->slirp = NULL;
c7f74643 FB	46	}
c7f74643 FB	47
460fec67	48	static int tftp_session_allocate(Slirp slirp, struct tftp_t tp)
c7f74643 FB	49	{
c7f74643 FB	50	struct tftp_session *spt;
c7f74643 FB	51	int k;
c7f74643 FB	52
c7f74643	53	for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
460fec67	54	spt = &slirp->tftp_sessions[k];
c7f74643	55
460fec67	56	if (!tftp_session_in_use(spt))
a3504c87	57	goto found;
c7f74643 FB	58
c7f74643 FB	59	/* sessions time out after 5 inactive seconds */
9367964a	60	if ((int)(curtime - spt->timestamp) > 5000) {
78be0566	61	tftp_session_terminate(spt);
a3504c87	62	goto found;
9367964a	63	}
c7f74643 FB	64	}
	65
	66	return -1;
	67
	68	found:
	69	memset(spt, 0, sizeof(*spt));
	70	memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
78be0566	71	spt->fd = -1;
c7f74643	72	spt->client_port = tp->udp.uh_sport;
460fec67	73	spt->slirp = slirp;
c7f74643 FB	74
	75	tftp_session_update(spt);
	76
	77	return k;
	78	}
	79
460fec67	80	static int tftp_session_find(Slirp slirp, struct tftp_t tp)
c7f74643 FB	81	{
	82	struct tftp_session *spt;
	83	int k;
	84
	85	for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
460fec67	86	spt = &slirp->tftp_sessions[k];
c7f74643	87
460fec67	88	if (tftp_session_in_use(spt)) {
c7f74643 FB	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
4aa401f3	100	static int tftp_read_data(struct tftp_session *spt, uint32_t block_nr,
b6dce92e	101	uint8_t *buf, int len)
c7f74643	102	{
78be0566	103	int bytes_read = 0;
c7f74643	104
78be0566 HP	105	if (spt->fd < 0) {
	106	spt->fd = open(spt->filename, O_RDONLY \| O_BINARY);
	107	}
c7f74643	108
78be0566 HP	109	if (spt->fd < 0) {
	110	return -1;
	111	}
c7f74643	112
78be0566 HP	113	if (len) {
78be0566 HP	114	lseek(spt->fd, block_nr * 512, SEEK_SET);
c7f74643	115
78be0566 HP	116	bytes_read = read(spt->fd, buf, len);
78be0566 HP	117	}
c7f74643	118
78be0566	119	return bytes_read;
c7f74643 FB	120	}
c7f74643 FB	121
5fafdf24	122	static int tftp_send_oack(struct tftp_session *spt,
95b1ad7a	123	const char *keys[], uint32_t values[], int nb,
1f697db9 TS	124	struct tftp_t *recv_tp)
	125	{
	126	struct sockaddr_in saddr, daddr;
	127	struct mbuf *m;
	128	struct tftp_t *tp;
95b1ad7a	129	int i, n = 0;
1f697db9	130
460fec67	131	m = m_get(spt->slirp);
1f697db9 TS	132
	133	if (!m)
	134	return -1;
	135
	136	memset(m->m_data, 0, m->m_size);
	137
9634d903	138	m->m_data += IF_MAXLINKHDR;
1f697db9 TS	139	tp = (void *)m->m_data;
1f697db9 TS	140	m->m_data += sizeof(struct udpiphdr);
3b46e624	141
1f697db9	142	tp->tp_op = htons(TFTP_OACK);
95b1ad7a HP	143	for (i = 0; i < nb; i++) {
	144	n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
	145	keys[i]) + 1;
	146	n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
	147	values[i]) + 1;
	148	}
1f697db9 TS	149
	150	saddr.sin_addr = recv_tp->ip.ip_dst;
	151	saddr.sin_port = recv_tp->udp.uh_dport;
3b46e624	152
1f697db9 TS	153	daddr.sin_addr = spt->client_ip;
	154	daddr.sin_port = spt->client_port;
	155
5fafdf24	156	m->m_len = sizeof(struct tftp_t) - 514 + n -
1f697db9 TS	157	sizeof(struct ip) - sizeof(struct udphdr);
	158	udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
	159
	160	return 0;
	161	}
	162
ef2d54d8	163	static void tftp_send_error(struct tftp_session *spt,
b6dce92e	164	uint16_t errorcode, const char *msg,
ef2d54d8	165	struct tftp_t *recv_tp)
c7f74643 FB	166	{
	167	struct sockaddr_in saddr, daddr;
	168	struct mbuf *m;
	169	struct tftp_t *tp;
c7f74643	170
460fec67	171	m = m_get(spt->slirp);
c7f74643 FB	172
c7f74643 FB	173	if (!m) {
ef2d54d8	174	goto out;
c7f74643 FB	175	}
	176
	177	memset(m->m_data, 0, m->m_size);
	178
9634d903	179	m->m_data += IF_MAXLINKHDR;
c7f74643 FB	180	tp = (void *)m->m_data;
c7f74643 FB	181	m->m_data += sizeof(struct udpiphdr);
3b46e624	182
c7f74643 FB	183	tp->tp_op = htons(TFTP_ERROR);
c7f74643 FB	184	tp->x.tp_error.tp_error_code = htons(errorcode);
b55266b5	185	pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg), msg);
c7f74643 FB	186
	187	saddr.sin_addr = recv_tp->ip.ip_dst;
	188	saddr.sin_port = recv_tp->udp.uh_dport;
	189
	190	daddr.sin_addr = spt->client_ip;
	191	daddr.sin_port = spt->client_port;
	192
5fafdf24	193	m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg) -
c7f74643 FB	194	sizeof(struct ip) - sizeof(struct udphdr);
	195
	196	udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
	197
ef2d54d8	198	out:
c7f74643	199	tftp_session_terminate(spt);
c7f74643 FB	200	}
c7f74643 FB	201
eb7faf0e JK	202	static void tftp_send_next_block(struct tftp_session *spt,
eb7faf0e JK	203	struct tftp_t *recv_tp)
c7f74643 FB	204	{
	205	struct sockaddr_in saddr, daddr;
	206	struct mbuf *m;
	207	struct tftp_t *tp;
	208	int nobytes;
	209
460fec67	210	m = m_get(spt->slirp);
c7f74643 FB	211
c7f74643 FB	212	if (!m) {
eb7faf0e	213	return;
c7f74643 FB	214	}
	215
	216	memset(m->m_data, 0, m->m_size);
	217
9634d903	218	m->m_data += IF_MAXLINKHDR;
c7f74643 FB	219	tp = (void *)m->m_data;
c7f74643 FB	220	m->m_data += sizeof(struct udpiphdr);
3b46e624	221
c7f74643	222	tp->tp_op = htons(TFTP_DATA);
4aa401f3	223	tp->x.tp_data.tp_block_nr = htons((spt->block_nr + 1) & 0xffff);
c7f74643 FB	224
	225	saddr.sin_addr = recv_tp->ip.ip_dst;
	226	saddr.sin_port = recv_tp->udp.uh_dport;
	227
	228	daddr.sin_addr = spt->client_ip;
	229	daddr.sin_port = spt->client_port;
	230
4aa401f3	231	nobytes = tftp_read_data(spt, spt->block_nr, tp->x.tp_data.tp_buf, 512);
c7f74643 FB	232
	233	if (nobytes < 0) {
	234	m_free(m);
	235
	236	/* send "file not found" error back */
	237
	238	tftp_send_error(spt, 1, "File not found", tp);
	239
eb7faf0e	240	return;
c7f74643 FB	241	}
c7f74643 FB	242
5fafdf24	243	m->m_len = sizeof(struct tftp_t) - (512 - nobytes) -
c7f74643 FB	244	sizeof(struct ip) - sizeof(struct udphdr);
	245
	246	udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
	247
	248	if (nobytes == 512) {
	249	tftp_session_update(spt);
	250	}
	251	else {
	252	tftp_session_terminate(spt);
	253	}
	254
4aa401f3	255	spt->block_nr++;
c7f74643 FB	256	}
c7f74643 FB	257
460fec67	258	static void tftp_handle_rrq(Slirp slirp, struct tftp_t tp, int pktlen)
c7f74643 FB	259	{
c7f74643 FB	260	struct tftp_session *spt;
20c24bf2	261	int s, k;
9367964a	262	size_t prefix_len;
20c24bf2	263	char *req_fname;
95b1ad7a HP	264	const char *option_name[2];
	265	uint32_t option_value[2];
	266	int nb_options = 0;
c7f74643	267
bfe4e172 TH	268	/* check if a session already exists and if so terminate it */
	269	s = tftp_session_find(slirp, tp);
	270	if (s >= 0) {
	271	tftp_session_terminate(&slirp->tftp_sessions[s]);
	272	}
	273
460fec67	274	s = tftp_session_allocate(slirp, tp);
c7f74643 FB	275
	276	if (s < 0) {
	277	return;
	278	}
	279
460fec67	280	spt = &slirp->tftp_sessions[s];
c7f74643	281
f8e3cbd3	282	/* unspecifed prefix means service disabled */
460fec67	283	if (!slirp->tftp_prefix) {
f8e3cbd3 JK	284	tftp_send_error(spt, 2, "Access violation", tp);
	285	return;
	286	}
	287
20c24bf2 JK	288	/* skip header fields */
20c24bf2 JK	289	k = 0;
89d2d3af	290	pktlen -= offsetof(struct tftp_t, x.tp_buf);
c7f74643	291
9367964a	292	/* prepend tftp_prefix */
460fec67	293	prefix_len = strlen(slirp->tftp_prefix);
7267c094	294	spt->filename = g_malloc(prefix_len + TFTP_FILENAME_MAX + 2);
460fec67	295	memcpy(spt->filename, slirp->tftp_prefix, prefix_len);
74efd61a	296	spt->filename[prefix_len] = '/';
9367964a	297
c7f74643	298	/* get name */
74efd61a	299	req_fname = spt->filename + prefix_len + 1;
c7f74643	300
20c24bf2 JK	301	while (1) {
	302	if (k >= TFTP_FILENAME_MAX \|\| k >= pktlen) {
	303	tftp_send_error(spt, 2, "Access violation", tp);
c7f74643 FB	304	return;
c7f74643 FB	305	}
89d2d3af	306	req_fname[k] = tp->x.tp_buf[k];
20c24bf2	307	if (req_fname[k++] == '\0') {
c7f74643 FB	308	break;
	309	}
	310	}
3b46e624	311
c7f74643	312	/* check mode */
20c24bf2 JK	313	if ((pktlen - k) < 6) {
20c24bf2 JK	314	tftp_send_error(spt, 2, "Access violation", tp);
c7f74643 FB	315	return;
c7f74643 FB	316	}
3b46e624	317
89d2d3af	318	if (strcasecmp(&tp->x.tp_buf[k], "octet") != 0) {
c7f74643 FB	319	tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
	320	return;
	321	}
	322
1f697db9 TS	323	k += 6; /* skipping octet */
1f697db9 TS	324
c7f74643	325	/* do sanity checks on the filename */
74efd61a JK	326	if (!strncmp(req_fname, "../", 3) \|\|
74efd61a JK	327	req_fname[strlen(req_fname) - 1] == '/' \|\|
9367964a	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
95b1ad7a	344	while (k < pktlen && nb_options < ARRAY_SIZE(option_name)) {
1f697db9 TS	345	const char key, value;
1f697db9 TS	346
89d2d3af	347	key = &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
89d2d3af	355	value = &tp->x.tp_buf[k];
1f697db9 TS	356	k += strlen(value) + 1;
1f697db9 TS	357
facf1a60	358	if (strcasecmp(key, "tsize") == 0) {
1f697db9 TS	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
95b1ad7a HP	371	option_name[nb_options] = "tsize";
	372	option_value[nb_options] = tsize;
	373	nb_options++;
	374	} else if (strcasecmp(key, "blksize") == 0) {
	375	int blksize = atoi(value);
	376
	377	/* If blksize option is bigger than what we will
	378	* emit, accept the option with our packet size.
	379	* Otherwise, simply do as we didn't see the option.
	380	*/
	381	if (blksize >= 512) {
	382	option_name[nb_options] = "blksize";
	383	option_value[nb_options] = 512;
	384	nb_options++;
	385	}
1f697db9 TS	386	}
	387	}
	388
95b1ad7a HP	389	if (nb_options > 0) {
	390	assert(nb_options <= ARRAY_SIZE(option_name));
	391	tftp_send_oack(spt, option_name, option_value, nb_options, tp);
	392	return;
	393	}
	394
4aa401f3 HP	395	spt->block_nr = 0;
4aa401f3 HP	396	tftp_send_next_block(spt, tp);
c7f74643 FB	397	}
c7f74643 FB	398
460fec67	399	static void tftp_handle_ack(Slirp slirp, struct tftp_t tp, int pktlen)
c7f74643 FB	400	{
	401	int s;
	402
460fec67	403	s = tftp_session_find(slirp, tp);
c7f74643 FB	404
	405	if (s < 0) {
	406	return;
	407	}
	408
eb7faf0e	409	tftp_send_next_block(&slirp->tftp_sessions[s], tp);
c7f74643 FB	410	}
c7f74643 FB	411
bfe4e172 TH	412	static void tftp_handle_error(Slirp slirp, struct tftp_t tp, int pktlen)
	413	{
	414	int s;
	415
	416	s = tftp_session_find(slirp, tp);
	417
	418	if (s < 0) {
	419	return;
	420	}
	421
	422	tftp_session_terminate(&slirp->tftp_sessions[s]);
	423	}
	424
c7f74643 FB	425	void tftp_input(struct mbuf *m)
	426	{
	427	struct tftp_t tp = (struct tftp_t )m->m_data;
	428
	429	switch(ntohs(tp->tp_op)) {
	430	case TFTP_RRQ:
460fec67	431	tftp_handle_rrq(m->slirp, tp, m->m_len);
c7f74643 FB	432	break;
	433
	434	case TFTP_ACK:
460fec67	435	tftp_handle_ack(m->slirp, tp, m->m_len);
c7f74643	436	break;
bfe4e172 TH	437
	438	case TFTP_ERROR:
	439	tftp_handle_error(m->slirp, tp, m->m_len);
	440	break;
c7f74643 FB	441	}
c7f74643 FB	442	}