[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 "qemu/osdep.h"
#include "slirp.h"
#include "qemu-common.h"
#include "qemu/cutils.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 sockaddr_storage *srcsas,
                                 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));
  spt->client_addr = *srcsas;
  spt->fd = -1;
  spt->block_size = 512;
  spt->client_port = tp->udp.uh_sport;
  spt->slirp = slirp;

  tftp_session_update(spt);

  return k;
}

static int tftp_session_find(Slirp *slirp, struct sockaddr_storage *srcsas,
                             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 (sockaddr_equal(&spt->client_addr, srcsas)) {
	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 * spt->block_size, SEEK_SET);

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

    return bytes_read;
}

static struct tftp_t *tftp_prep_mbuf_data(struct tftp_session *spt,
                                          struct mbuf *m)
{
    struct tftp_t *tp;

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

    m->m_data += IF_MAXLINKHDR;
    if (spt->client_addr.ss_family == AF_INET6) {
        m->m_data += sizeof(struct ip6);
    } else {
        m->m_data += sizeof(struct ip);
    }
    tp = (void *)m->m_data;
    m->m_data += sizeof(struct udphdr);

    return tp;
}

static void tftp_udp_output(struct tftp_session *spt, struct mbuf *m,
                            struct tftp_t *recv_tp)
{
    if (spt->client_addr.ss_family == AF_INET6) {
        struct sockaddr_in6 sa6, da6;

        sa6.sin6_addr = spt->slirp->vhost_addr6;
        sa6.sin6_port = recv_tp->udp.uh_dport;
        da6.sin6_addr = ((struct sockaddr_in6 *)&spt->client_addr)->sin6_addr;
        da6.sin6_port = spt->client_port;

        udp6_output(NULL, m, &sa6, &da6);
    } else {
        struct sockaddr_in sa4, da4;

        sa4.sin_addr = spt->slirp->vhost_addr;
        sa4.sin_port = recv_tp->udp.uh_dport;
        da4.sin_addr = ((struct sockaddr_in *)&spt->client_addr)->sin_addr;
        da4.sin_port = spt->client_port;

        udp_output(NULL, m, &sa4, &da4, IPTOS_LOWDELAY);
    }
}

static int tftp_send_oack(struct tftp_session *spt,
                          const char *keys[], uint32_t values[], int nb,
                          struct tftp_t *recv_tp)
{
    struct mbuf *m;
    struct tftp_t *tp;
    int i, n = 0;

    m = m_get(spt->slirp);

    if (!m)
        return -1;

    tp = tftp_prep_mbuf_data(spt, m);

    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;
    }

    m->m_len = sizeof(struct tftp_t) - (TFTP_BLOCKSIZE_MAX + 2) + n
               - sizeof(struct udphdr);
    tftp_udp_output(spt, m, recv_tp);

    return 0;
}

static void tftp_send_error(struct tftp_session *spt,
                            uint16_t errorcode, const char *msg,
                            struct tftp_t *recv_tp)
{
  struct mbuf *m;
  struct tftp_t *tp;

  m = m_get(spt->slirp);

  if (!m) {
    goto out;
  }

  tp = tftp_prep_mbuf_data(spt, m);

  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);

  m->m_len = sizeof(struct tftp_t) - (TFTP_BLOCKSIZE_MAX + 2) + 3 + strlen(msg)
             - sizeof(struct udphdr);
  tftp_udp_output(spt, m, recv_tp);

out:
  tftp_session_terminate(spt);
}

static void tftp_send_next_block(struct tftp_session *spt,
                                 struct tftp_t *recv_tp)
{
  struct mbuf *m;
  struct tftp_t *tp;
  int nobytes;

  m = m_get(spt->slirp);

  if (!m) {
    return;
  }

  tp = tftp_prep_mbuf_data(spt, m);

  tp->tp_op = htons(TFTP_DATA);
  tp->x.tp_data.tp_block_nr = htons((spt->block_nr + 1) & 0xffff);

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

  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) - (TFTP_BLOCKSIZE_MAX - nobytes)
             - sizeof(struct udphdr);
  tftp_udp_output(spt, m, recv_tp);

  if (nobytes == spt->block_size) {
    tftp_session_update(spt);
  }
  else {
    tftp_session_terminate(spt);
  }

  spt->block_nr++;
}

static void tftp_handle_rrq(Slirp *slirp, struct sockaddr_storage *srcsas,
                            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, srcsas, tp);
  if (s >= 0) {
    tftp_session_terminate(&slirp->tftp_sessions[s]);
  }

  s = tftp_session_allocate(slirp, srcsas, tp);

  if (s < 0) {
    return;
  }

  spt = &slirp->tftp_sessions[s];

  /* unspecified 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);

          /* Accept blksize up to our maximum size */
          if (blksize > 0) {
              spt->block_size = MIN(blksize, TFTP_BLOCKSIZE_MAX);
              option_name[nb_options] = "blksize";
              option_value[nb_options] = spt->block_size;
              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 sockaddr_storage *srcsas,
                            struct tftp_t *tp, int pktlen)
{
  int s;

  s = tftp_session_find(slirp, srcsas, tp);

  if (s < 0) {
    return;
  }

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

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

  s = tftp_session_find(slirp, srcsas, tp);

  if (s < 0) {
    return;
  }

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

void tftp_input(struct sockaddr_storage *srcsas, 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, srcsas, tp, m->m_len);
    break;

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

  case TFTP_ERROR:
    tftp_handle_error(m->slirp, srcsas, 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
7df7482b	25	#include "qemu/osdep.h"
a9c94277	26	#include "slirp.h"
0d62c4cf	27	#include "qemu-common.h"
f348b6d1	28	#include "qemu/cutils.h"
c7f74643	29
460fec67 JK	30	static inline int tftp_session_in_use(struct tftp_session *spt)
	31	{
	32	return (spt->slirp != NULL);
	33	}
c7f74643	34
460fec67	35	static inline void tftp_session_update(struct tftp_session *spt)
c7f74643	36	{
a3504c87	37	spt->timestamp = curtime;
c7f74643 FB	38	}
	39
	40	static void tftp_session_terminate(struct tftp_session *spt)
	41	{
78be0566 HP	42	if (spt->fd >= 0) {
	43	close(spt->fd);
	44	spt->fd = -1;
	45	}
7267c094	46	g_free(spt->filename);
460fec67	47	spt->slirp = NULL;
c7f74643 FB	48	}
c7f74643 FB	49
fad7fb9c TH	50	static int tftp_session_allocate(Slirp slirp, struct sockaddr_storage srcsas,
fad7fb9c TH	51	struct tftp_t *tp)
c7f74643 FB	52	{
c7f74643 FB	53	struct tftp_session *spt;
c7f74643 FB	54	int k;
c7f74643 FB	55
c7f74643	56	for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
460fec67	57	spt = &slirp->tftp_sessions[k];
c7f74643	58
460fec67	59	if (!tftp_session_in_use(spt))
a3504c87	60	goto found;
c7f74643 FB	61
c7f74643 FB	62	/* sessions time out after 5 inactive seconds */
9367964a	63	if ((int)(curtime - spt->timestamp) > 5000) {
78be0566	64	tftp_session_terminate(spt);
a3504c87	65	goto found;
9367964a	66	}
c7f74643 FB	67	}
	68
	69	return -1;
	70
	71	found:
	72	memset(spt, 0, sizeof(*spt));
fad7fb9c	73	spt->client_addr = *srcsas;
78be0566	74	spt->fd = -1;
9443598d	75	spt->block_size = 512;
c7f74643	76	spt->client_port = tp->udp.uh_sport;
460fec67	77	spt->slirp = slirp;
c7f74643 FB	78
	79	tftp_session_update(spt);
	80
	81	return k;
	82	}
	83
fad7fb9c TH	84	static int tftp_session_find(Slirp slirp, struct sockaddr_storage srcsas,
fad7fb9c TH	85	struct tftp_t *tp)
c7f74643 FB	86	{
	87	struct tftp_session *spt;
	88	int k;
	89
	90	for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
460fec67	91	spt = &slirp->tftp_sessions[k];
c7f74643	92
460fec67	93	if (tftp_session_in_use(spt)) {
fad7fb9c	94	if (sockaddr_equal(&spt->client_addr, srcsas)) {
c7f74643 FB	95	if (spt->client_port == tp->udp.uh_sport) {
	96	return k;
	97	}
	98	}
	99	}
	100	}
	101
	102	return -1;
	103	}
	104
4aa401f3	105	static int tftp_read_data(struct tftp_session *spt, uint32_t block_nr,
b6dce92e	106	uint8_t *buf, int len)
c7f74643	107	{
78be0566	108	int bytes_read = 0;
c7f74643	109
78be0566 HP	110	if (spt->fd < 0) {
	111	spt->fd = open(spt->filename, O_RDONLY \| O_BINARY);
	112	}
c7f74643	113
78be0566 HP	114	if (spt->fd < 0) {
	115	return -1;
	116	}
c7f74643	117
78be0566	118	if (len) {
9443598d	119	lseek(spt->fd, block_nr * spt->block_size, SEEK_SET);
c7f74643	120
78be0566 HP	121	bytes_read = read(spt->fd, buf, len);
78be0566 HP	122	}
c7f74643	123
78be0566	124	return bytes_read;
c7f74643 FB	125	}
c7f74643 FB	126
fad7fb9c TH	127	static struct tftp_t tftp_prep_mbuf_data(struct tftp_session spt,
	128	struct mbuf *m)
	129	{
	130	struct tftp_t *tp;
	131
	132	memset(m->m_data, 0, m->m_size);
	133
	134	m->m_data += IF_MAXLINKHDR;
	135	if (spt->client_addr.ss_family == AF_INET6) {
	136	m->m_data += sizeof(struct ip6);
	137	} else {
	138	m->m_data += sizeof(struct ip);
	139	}
	140	tp = (void *)m->m_data;
	141	m->m_data += sizeof(struct udphdr);
	142
	143	return tp;
	144	}
	145
	146	static void tftp_udp_output(struct tftp_session spt, struct mbuf m,
	147	struct tftp_t *recv_tp)
	148	{
	149	if (spt->client_addr.ss_family == AF_INET6) {
	150	struct sockaddr_in6 sa6, da6;
	151
	152	sa6.sin6_addr = spt->slirp->vhost_addr6;
	153	sa6.sin6_port = recv_tp->udp.uh_dport;
	154	da6.sin6_addr = ((struct sockaddr_in6 *)&spt->client_addr)->sin6_addr;
	155	da6.sin6_port = spt->client_port;
	156
	157	udp6_output(NULL, m, &sa6, &da6);
	158	} else {
	159	struct sockaddr_in sa4, da4;
	160
	161	sa4.sin_addr = spt->slirp->vhost_addr;
	162	sa4.sin_port = recv_tp->udp.uh_dport;
	163	da4.sin_addr = ((struct sockaddr_in *)&spt->client_addr)->sin_addr;
	164	da4.sin_port = spt->client_port;
	165
	166	udp_output(NULL, m, &sa4, &da4, IPTOS_LOWDELAY);
	167	}
	168	}
	169
5fafdf24	170	static int tftp_send_oack(struct tftp_session *spt,
95b1ad7a	171	const char *keys[], uint32_t values[], int nb,
1f697db9 TS	172	struct tftp_t *recv_tp)
1f697db9 TS	173	{
1f697db9 TS	174	struct mbuf *m;
1f697db9 TS	175	struct tftp_t *tp;
95b1ad7a	176	int i, n = 0;
1f697db9	177
460fec67	178	m = m_get(spt->slirp);
1f697db9 TS	179
1f697db9 TS	180	if (!m)
fad7fb9c	181	return -1;
1f697db9	182
fad7fb9c	183	tp = tftp_prep_mbuf_data(spt, m);
3b46e624	184
1f697db9	185	tp->tp_op = htons(TFTP_OACK);
95b1ad7a HP	186	for (i = 0; i < nb; i++) {
	187	n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
	188	keys[i]) + 1;
	189	n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
	190	values[i]) + 1;
	191	}
1f697db9	192
9443598d HP	193	m->m_len = sizeof(struct tftp_t) - (TFTP_BLOCKSIZE_MAX + 2) + n
9443598d HP	194	- sizeof(struct udphdr);
fad7fb9c	195	tftp_udp_output(spt, m, recv_tp);
1f697db9 TS	196
	197	return 0;
	198	}
	199
ef2d54d8	200	static void tftp_send_error(struct tftp_session *spt,
b6dce92e	201	uint16_t errorcode, const char *msg,
ef2d54d8	202	struct tftp_t *recv_tp)
c7f74643	203	{
c7f74643 FB	204	struct mbuf *m;
c7f74643 FB	205	struct tftp_t *tp;
c7f74643	206
460fec67	207	m = m_get(spt->slirp);
c7f74643 FB	208
c7f74643 FB	209	if (!m) {
ef2d54d8	210	goto out;
c7f74643 FB	211	}
c7f74643 FB	212
fad7fb9c	213	tp = tftp_prep_mbuf_data(spt, m);
3b46e624	214
c7f74643 FB	215	tp->tp_op = htons(TFTP_ERROR);
c7f74643 FB	216	tp->x.tp_error.tp_error_code = htons(errorcode);
b55266b5	217	pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg), msg);
c7f74643	218
9443598d	219	m->m_len = sizeof(struct tftp_t) - (TFTP_BLOCKSIZE_MAX + 2) + 3 + strlen(msg)
fad7fb9c TH	220	- sizeof(struct udphdr);
fad7fb9c TH	221	tftp_udp_output(spt, m, recv_tp);
c7f74643	222
ef2d54d8	223	out:
c7f74643	224	tftp_session_terminate(spt);
c7f74643 FB	225	}
c7f74643 FB	226
eb7faf0e JK	227	static void tftp_send_next_block(struct tftp_session *spt,
eb7faf0e JK	228	struct tftp_t *recv_tp)
c7f74643	229	{
c7f74643 FB	230	struct mbuf *m;
	231	struct tftp_t *tp;
	232	int nobytes;
	233
460fec67	234	m = m_get(spt->slirp);
c7f74643 FB	235
c7f74643 FB	236	if (!m) {
eb7faf0e	237	return;
c7f74643 FB	238	}
c7f74643 FB	239
fad7fb9c	240	tp = tftp_prep_mbuf_data(spt, m);
3b46e624	241
c7f74643	242	tp->tp_op = htons(TFTP_DATA);
4aa401f3	243	tp->x.tp_data.tp_block_nr = htons((spt->block_nr + 1) & 0xffff);
c7f74643	244
9443598d HP	245	nobytes = tftp_read_data(spt, spt->block_nr, tp->x.tp_data.tp_buf,
9443598d HP	246	spt->block_size);
c7f74643 FB	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
eb7faf0e	255	return;
c7f74643 FB	256	}
c7f74643 FB	257
9443598d HP	258	m->m_len = sizeof(struct tftp_t) - (TFTP_BLOCKSIZE_MAX - nobytes)
9443598d HP	259	- sizeof(struct udphdr);
fad7fb9c	260	tftp_udp_output(spt, m, recv_tp);
c7f74643	261
9443598d	262	if (nobytes == spt->block_size) {
c7f74643 FB	263	tftp_session_update(spt);
	264	}
	265	else {
	266	tftp_session_terminate(spt);
	267	}
	268
4aa401f3	269	spt->block_nr++;
c7f74643 FB	270	}
c7f74643 FB	271
fad7fb9c TH	272	static void tftp_handle_rrq(Slirp slirp, struct sockaddr_storage srcsas,
fad7fb9c TH	273	struct tftp_t *tp, int pktlen)
c7f74643 FB	274	{
c7f74643 FB	275	struct tftp_session *spt;
20c24bf2	276	int s, k;
9367964a	277	size_t prefix_len;
20c24bf2	278	char *req_fname;
95b1ad7a HP	279	const char *option_name[2];
	280	uint32_t option_value[2];
	281	int nb_options = 0;
c7f74643	282
bfe4e172	283	/* check if a session already exists and if so terminate it */
fad7fb9c	284	s = tftp_session_find(slirp, srcsas, tp);
bfe4e172 TH	285	if (s >= 0) {
	286	tftp_session_terminate(&slirp->tftp_sessions[s]);
	287	}
	288
fad7fb9c	289	s = tftp_session_allocate(slirp, srcsas, tp);
c7f74643 FB	290
	291	if (s < 0) {
	292	return;
	293	}
	294
460fec67	295	spt = &slirp->tftp_sessions[s];
c7f74643	296
dc6fb73d	297	/* unspecified prefix means service disabled */
460fec67	298	if (!slirp->tftp_prefix) {
f8e3cbd3 JK	299	tftp_send_error(spt, 2, "Access violation", tp);
	300	return;
	301	}
	302
20c24bf2 JK	303	/* skip header fields */
20c24bf2 JK	304	k = 0;
89d2d3af	305	pktlen -= offsetof(struct tftp_t, x.tp_buf);
c7f74643	306
9367964a	307	/* prepend tftp_prefix */
460fec67	308	prefix_len = strlen(slirp->tftp_prefix);
7267c094	309	spt->filename = g_malloc(prefix_len + TFTP_FILENAME_MAX + 2);
460fec67	310	memcpy(spt->filename, slirp->tftp_prefix, prefix_len);
74efd61a	311	spt->filename[prefix_len] = '/';
9367964a	312
c7f74643	313	/* get name */
74efd61a	314	req_fname = spt->filename + prefix_len + 1;
c7f74643	315
20c24bf2 JK	316	while (1) {
	317	if (k >= TFTP_FILENAME_MAX \|\| k >= pktlen) {
	318	tftp_send_error(spt, 2, "Access violation", tp);
c7f74643 FB	319	return;
c7f74643 FB	320	}
89d2d3af	321	req_fname[k] = tp->x.tp_buf[k];
20c24bf2	322	if (req_fname[k++] == '\0') {
c7f74643 FB	323	break;
	324	}
	325	}
3b46e624	326
c7f74643	327	/* check mode */
20c24bf2 JK	328	if ((pktlen - k) < 6) {
20c24bf2 JK	329	tftp_send_error(spt, 2, "Access violation", tp);
c7f74643 FB	330	return;
c7f74643 FB	331	}
3b46e624	332
89d2d3af	333	if (strcasecmp(&tp->x.tp_buf[k], "octet") != 0) {
c7f74643 FB	334	tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
	335	return;
	336	}
	337
1f697db9 TS	338	k += 6; /* skipping octet */
1f697db9 TS	339
c7f74643	340	/* do sanity checks on the filename */
74efd61a JK	341	if (!strncmp(req_fname, "../", 3) \|\|
74efd61a JK	342	req_fname[strlen(req_fname) - 1] == '/' \|\|
9367964a	343	strstr(req_fname, "/../")) {
c7f74643 FB	344	tftp_send_error(spt, 2, "Access violation", tp);
	345	return;
	346	}
	347
c7f74643	348	/* check if the file exists */
20c24bf2	349	if (tftp_read_data(spt, 0, NULL, 0) < 0) {
c7f74643 FB	350	tftp_send_error(spt, 1, "File not found", tp);
	351	return;
	352	}
	353
20c24bf2	354	if (tp->x.tp_buf[pktlen - 1] != 0) {
1f697db9 TS	355	tftp_send_error(spt, 2, "Access violation", tp);
	356	return;
	357	}
	358
95b1ad7a	359	while (k < pktlen && nb_options < ARRAY_SIZE(option_name)) {
1f697db9 TS	360	const char key, value;
1f697db9 TS	361
89d2d3af	362	key = &tp->x.tp_buf[k];
1f697db9 TS	363	k += strlen(key) + 1;
1f697db9 TS	364
20c24bf2	365	if (k >= pktlen) {
1f697db9 TS	366	tftp_send_error(spt, 2, "Access violation", tp);
	367	return;
	368	}
	369
89d2d3af	370	value = &tp->x.tp_buf[k];
1f697db9 TS	371	k += strlen(value) + 1;
1f697db9 TS	372
facf1a60	373	if (strcasecmp(key, "tsize") == 0) {
1f697db9 TS	374	int tsize = atoi(value);
	375	struct stat stat_p;
	376
f8e3cbd3	377	if (tsize == 0) {
9367964a	378	if (stat(spt->filename, &stat_p) == 0)
1f697db9 TS	379	tsize = stat_p.st_size;
	380	else {
	381	tftp_send_error(spt, 1, "File not found", tp);
	382	return;
	383	}
	384	}
	385
95b1ad7a HP	386	option_name[nb_options] = "tsize";
	387	option_value[nb_options] = tsize;
	388	nb_options++;
	389	} else if (strcasecmp(key, "blksize") == 0) {
	390	int blksize = atoi(value);
	391
9443598d HP	392	/* Accept blksize up to our maximum size */
	393	if (blksize > 0) {
	394	spt->block_size = MIN(blksize, TFTP_BLOCKSIZE_MAX);
95b1ad7a	395	option_name[nb_options] = "blksize";
9443598d	396	option_value[nb_options] = spt->block_size;
95b1ad7a HP	397	nb_options++;
95b1ad7a HP	398	}
1f697db9 TS	399	}
	400	}
	401
95b1ad7a HP	402	if (nb_options > 0) {
	403	assert(nb_options <= ARRAY_SIZE(option_name));
	404	tftp_send_oack(spt, option_name, option_value, nb_options, tp);
	405	return;
	406	}
	407
4aa401f3 HP	408	spt->block_nr = 0;
4aa401f3 HP	409	tftp_send_next_block(spt, tp);
c7f74643 FB	410	}
c7f74643 FB	411
fad7fb9c TH	412	static void tftp_handle_ack(Slirp slirp, struct sockaddr_storage srcsas,
fad7fb9c TH	413	struct tftp_t *tp, int pktlen)
c7f74643 FB	414	{
	415	int s;
	416
fad7fb9c	417	s = tftp_session_find(slirp, srcsas, tp);
c7f74643 FB	418
	419	if (s < 0) {
	420	return;
	421	}
	422
eb7faf0e	423	tftp_send_next_block(&slirp->tftp_sessions[s], tp);
c7f74643 FB	424	}
c7f74643 FB	425
fad7fb9c TH	426	static void tftp_handle_error(Slirp slirp, struct sockaddr_storage srcsas,
fad7fb9c TH	427	struct tftp_t *tp, int pktlen)
bfe4e172 TH	428	{
	429	int s;
	430
fad7fb9c	431	s = tftp_session_find(slirp, srcsas, tp);
bfe4e172 TH	432
	433	if (s < 0) {
	434	return;
	435	}
	436
	437	tftp_session_terminate(&slirp->tftp_sessions[s]);
	438	}
	439
fad7fb9c	440	void tftp_input(struct sockaddr_storage srcsas, struct mbuf m)
c7f74643 FB	441	{
	442	struct tftp_t tp = (struct tftp_t )m->m_data;
	443
	444	switch(ntohs(tp->tp_op)) {
	445	case TFTP_RRQ:
fad7fb9c	446	tftp_handle_rrq(m->slirp, srcsas, tp, m->m_len);
c7f74643 FB	447	break;
	448
	449	case TFTP_ACK:
fad7fb9c	450	tftp_handle_ack(m->slirp, srcsas, tp, m->m_len);
c7f74643	451	break;
bfe4e172 TH	452
bfe4e172 TH	453	case TFTP_ERROR:
fad7fb9c	454	tftp_handle_error(m->slirp, srcsas, tp, m->m_len);
bfe4e172	455	break;
c7f74643 FB	456	}
c7f74643 FB	457	}