[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 "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->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 * 512, 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) - 514 + 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) - 514 + 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, 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 udphdr);
  tftp_udp_output(spt, m, recv_tp);

  if (nobytes == 512) {
    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);

          /* 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 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 <[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
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;
c7f74643	75	spt->client_port = tp->udp.uh_sport;
460fec67	76	spt->slirp = slirp;
c7f74643 FB	77
	78	tftp_session_update(spt);
	79
	80	return k;
	81	}
	82
fad7fb9c TH	83	static int tftp_session_find(Slirp slirp, struct sockaddr_storage srcsas,
fad7fb9c TH	84	struct tftp_t *tp)
c7f74643 FB	85	{
	86	struct tftp_session *spt;
	87	int k;
	88
	89	for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
460fec67	90	spt = &slirp->tftp_sessions[k];
c7f74643	91
460fec67	92	if (tftp_session_in_use(spt)) {
fad7fb9c	93	if (sockaddr_equal(&spt->client_addr, srcsas)) {
c7f74643 FB	94	if (spt->client_port == tp->udp.uh_sport) {
	95	return k;
	96	}
	97	}
	98	}
	99	}
	100
	101	return -1;
	102	}
	103
4aa401f3	104	static int tftp_read_data(struct tftp_session *spt, uint32_t block_nr,
b6dce92e	105	uint8_t *buf, int len)
c7f74643	106	{
78be0566	107	int bytes_read = 0;
c7f74643	108
78be0566 HP	109	if (spt->fd < 0) {
	110	spt->fd = open(spt->filename, O_RDONLY \| O_BINARY);
	111	}
c7f74643	112
78be0566 HP	113	if (spt->fd < 0) {
	114	return -1;
	115	}
c7f74643	116
78be0566 HP	117	if (len) {
78be0566 HP	118	lseek(spt->fd, block_nr * 512, SEEK_SET);
c7f74643	119
78be0566 HP	120	bytes_read = read(spt->fd, buf, len);
78be0566 HP	121	}
c7f74643	122
78be0566	123	return bytes_read;
c7f74643 FB	124	}
c7f74643 FB	125
fad7fb9c TH	126	static struct tftp_t tftp_prep_mbuf_data(struct tftp_session spt,
	127	struct mbuf *m)
	128	{
	129	struct tftp_t *tp;
	130
	131	memset(m->m_data, 0, m->m_size);
	132
	133	m->m_data += IF_MAXLINKHDR;
	134	if (spt->client_addr.ss_family == AF_INET6) {
	135	m->m_data += sizeof(struct ip6);
	136	} else {
	137	m->m_data += sizeof(struct ip);
	138	}
	139	tp = (void *)m->m_data;
	140	m->m_data += sizeof(struct udphdr);
	141
	142	return tp;
	143	}
	144
	145	static void tftp_udp_output(struct tftp_session spt, struct mbuf m,
	146	struct tftp_t *recv_tp)
	147	{
	148	if (spt->client_addr.ss_family == AF_INET6) {
	149	struct sockaddr_in6 sa6, da6;
	150
	151	sa6.sin6_addr = spt->slirp->vhost_addr6;
	152	sa6.sin6_port = recv_tp->udp.uh_dport;
	153	da6.sin6_addr = ((struct sockaddr_in6 *)&spt->client_addr)->sin6_addr;
	154	da6.sin6_port = spt->client_port;
	155
	156	udp6_output(NULL, m, &sa6, &da6);
	157	} else {
	158	struct sockaddr_in sa4, da4;
	159
	160	sa4.sin_addr = spt->slirp->vhost_addr;
	161	sa4.sin_port = recv_tp->udp.uh_dport;
	162	da4.sin_addr = ((struct sockaddr_in *)&spt->client_addr)->sin_addr;
	163	da4.sin_port = spt->client_port;
	164
	165	udp_output(NULL, m, &sa4, &da4, IPTOS_LOWDELAY);
	166	}
	167	}
	168
5fafdf24	169	static int tftp_send_oack(struct tftp_session *spt,
95b1ad7a	170	const char *keys[], uint32_t values[], int nb,
1f697db9 TS	171	struct tftp_t *recv_tp)
1f697db9 TS	172	{
1f697db9 TS	173	struct mbuf *m;
1f697db9 TS	174	struct tftp_t *tp;
95b1ad7a	175	int i, n = 0;
1f697db9	176
460fec67	177	m = m_get(spt->slirp);
1f697db9 TS	178
1f697db9 TS	179	if (!m)
fad7fb9c	180	return -1;
1f697db9	181
fad7fb9c	182	tp = tftp_prep_mbuf_data(spt, m);
3b46e624	183
1f697db9	184	tp->tp_op = htons(TFTP_OACK);
95b1ad7a HP	185	for (i = 0; i < nb; i++) {
	186	n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
	187	keys[i]) + 1;
	188	n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
	189	values[i]) + 1;
	190	}
1f697db9	191
fad7fb9c TH	192	m->m_len = sizeof(struct tftp_t) - 514 + n - sizeof(struct udphdr);
fad7fb9c TH	193	tftp_udp_output(spt, m, recv_tp);
1f697db9 TS	194
	195	return 0;
	196	}
	197
ef2d54d8	198	static void tftp_send_error(struct tftp_session *spt,
b6dce92e	199	uint16_t errorcode, const char *msg,
ef2d54d8	200	struct tftp_t *recv_tp)
c7f74643	201	{
c7f74643 FB	202	struct mbuf *m;
c7f74643 FB	203	struct tftp_t *tp;
c7f74643	204
460fec67	205	m = m_get(spt->slirp);
c7f74643 FB	206
c7f74643 FB	207	if (!m) {
ef2d54d8	208	goto out;
c7f74643 FB	209	}
c7f74643 FB	210
fad7fb9c	211	tp = tftp_prep_mbuf_data(spt, m);
3b46e624	212
c7f74643 FB	213	tp->tp_op = htons(TFTP_ERROR);
c7f74643 FB	214	tp->x.tp_error.tp_error_code = htons(errorcode);
b55266b5	215	pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg), msg);
c7f74643	216
fad7fb9c TH	217	m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg)
	218	- sizeof(struct udphdr);
	219	tftp_udp_output(spt, m, recv_tp);
c7f74643	220
ef2d54d8	221	out:
c7f74643	222	tftp_session_terminate(spt);
c7f74643 FB	223	}
c7f74643 FB	224
eb7faf0e JK	225	static void tftp_send_next_block(struct tftp_session *spt,
eb7faf0e JK	226	struct tftp_t *recv_tp)
c7f74643	227	{
c7f74643 FB	228	struct mbuf *m;
	229	struct tftp_t *tp;
	230	int nobytes;
	231
460fec67	232	m = m_get(spt->slirp);
c7f74643 FB	233
c7f74643 FB	234	if (!m) {
eb7faf0e	235	return;
c7f74643 FB	236	}
c7f74643 FB	237
fad7fb9c	238	tp = tftp_prep_mbuf_data(spt, m);
3b46e624	239
c7f74643	240	tp->tp_op = htons(TFTP_DATA);
4aa401f3	241	tp->x.tp_data.tp_block_nr = htons((spt->block_nr + 1) & 0xffff);
c7f74643	242
4aa401f3	243	nobytes = tftp_read_data(spt, spt->block_nr, tp->x.tp_data.tp_buf, 512);
c7f74643 FB	244
	245	if (nobytes < 0) {
	246	m_free(m);
	247
	248	/* send "file not found" error back */
	249
	250	tftp_send_error(spt, 1, "File not found", tp);
	251
eb7faf0e	252	return;
c7f74643 FB	253	}
c7f74643 FB	254
fad7fb9c TH	255	m->m_len = sizeof(struct tftp_t) - (512 - nobytes) - sizeof(struct udphdr);
fad7fb9c TH	256	tftp_udp_output(spt, m, recv_tp);
c7f74643 FB	257
	258	if (nobytes == 512) {
	259	tftp_session_update(spt);
	260	}
	261	else {
	262	tftp_session_terminate(spt);
	263	}
	264
4aa401f3	265	spt->block_nr++;
c7f74643 FB	266	}
c7f74643 FB	267
fad7fb9c TH	268	static void tftp_handle_rrq(Slirp slirp, struct sockaddr_storage srcsas,
fad7fb9c TH	269	struct tftp_t *tp, int pktlen)
c7f74643 FB	270	{
c7f74643 FB	271	struct tftp_session *spt;
20c24bf2	272	int s, k;
9367964a	273	size_t prefix_len;
20c24bf2	274	char *req_fname;
95b1ad7a HP	275	const char *option_name[2];
	276	uint32_t option_value[2];
	277	int nb_options = 0;
c7f74643	278
bfe4e172	279	/* check if a session already exists and if so terminate it */
fad7fb9c	280	s = tftp_session_find(slirp, srcsas, tp);
bfe4e172 TH	281	if (s >= 0) {
	282	tftp_session_terminate(&slirp->tftp_sessions[s]);
	283	}
	284
fad7fb9c	285	s = tftp_session_allocate(slirp, srcsas, tp);
c7f74643 FB	286
	287	if (s < 0) {
	288	return;
	289	}
	290
460fec67	291	spt = &slirp->tftp_sessions[s];
c7f74643	292
dc6fb73d	293	/* unspecified prefix means service disabled */
460fec67	294	if (!slirp->tftp_prefix) {
f8e3cbd3 JK	295	tftp_send_error(spt, 2, "Access violation", tp);
	296	return;
	297	}
	298
20c24bf2 JK	299	/* skip header fields */
20c24bf2 JK	300	k = 0;
89d2d3af	301	pktlen -= offsetof(struct tftp_t, x.tp_buf);
c7f74643	302
9367964a	303	/* prepend tftp_prefix */
460fec67	304	prefix_len = strlen(slirp->tftp_prefix);
7267c094	305	spt->filename = g_malloc(prefix_len + TFTP_FILENAME_MAX + 2);
460fec67	306	memcpy(spt->filename, slirp->tftp_prefix, prefix_len);
74efd61a	307	spt->filename[prefix_len] = '/';
9367964a	308
c7f74643	309	/* get name */
74efd61a	310	req_fname = spt->filename + prefix_len + 1;
c7f74643	311
20c24bf2 JK	312	while (1) {
	313	if (k >= TFTP_FILENAME_MAX \|\| k >= pktlen) {
	314	tftp_send_error(spt, 2, "Access violation", tp);
c7f74643 FB	315	return;
c7f74643 FB	316	}
89d2d3af	317	req_fname[k] = tp->x.tp_buf[k];
20c24bf2	318	if (req_fname[k++] == '\0') {
c7f74643 FB	319	break;
	320	}
	321	}
3b46e624	322
c7f74643	323	/* check mode */
20c24bf2 JK	324	if ((pktlen - k) < 6) {
20c24bf2 JK	325	tftp_send_error(spt, 2, "Access violation", tp);
c7f74643 FB	326	return;
c7f74643 FB	327	}
3b46e624	328
89d2d3af	329	if (strcasecmp(&tp->x.tp_buf[k], "octet") != 0) {
c7f74643 FB	330	tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
	331	return;
	332	}
	333
1f697db9 TS	334	k += 6; /* skipping octet */
1f697db9 TS	335
c7f74643	336	/* do sanity checks on the filename */
74efd61a JK	337	if (!strncmp(req_fname, "../", 3) \|\|
74efd61a JK	338	req_fname[strlen(req_fname) - 1] == '/' \|\|
9367964a	339	strstr(req_fname, "/../")) {
c7f74643 FB	340	tftp_send_error(spt, 2, "Access violation", tp);
	341	return;
	342	}
	343
c7f74643	344	/* check if the file exists */
20c24bf2	345	if (tftp_read_data(spt, 0, NULL, 0) < 0) {
c7f74643 FB	346	tftp_send_error(spt, 1, "File not found", tp);
	347	return;
	348	}
	349
20c24bf2	350	if (tp->x.tp_buf[pktlen - 1] != 0) {
1f697db9 TS	351	tftp_send_error(spt, 2, "Access violation", tp);
	352	return;
	353	}
	354
95b1ad7a	355	while (k < pktlen && nb_options < ARRAY_SIZE(option_name)) {
1f697db9 TS	356	const char key, value;
1f697db9 TS	357
89d2d3af	358	key = &tp->x.tp_buf[k];
1f697db9 TS	359	k += strlen(key) + 1;
1f697db9 TS	360
20c24bf2	361	if (k >= pktlen) {
1f697db9 TS	362	tftp_send_error(spt, 2, "Access violation", tp);
	363	return;
	364	}
	365
89d2d3af	366	value = &tp->x.tp_buf[k];
1f697db9 TS	367	k += strlen(value) + 1;
1f697db9 TS	368
facf1a60	369	if (strcasecmp(key, "tsize") == 0) {
1f697db9 TS	370	int tsize = atoi(value);
	371	struct stat stat_p;
	372
f8e3cbd3	373	if (tsize == 0) {
9367964a	374	if (stat(spt->filename, &stat_p) == 0)
1f697db9 TS	375	tsize = stat_p.st_size;
	376	else {
	377	tftp_send_error(spt, 1, "File not found", tp);
	378	return;
	379	}
	380	}
	381
95b1ad7a HP	382	option_name[nb_options] = "tsize";
	383	option_value[nb_options] = tsize;
	384	nb_options++;
	385	} else if (strcasecmp(key, "blksize") == 0) {
	386	int blksize = atoi(value);
	387
	388	/* If blksize option is bigger than what we will
	389	* emit, accept the option with our packet size.
	390	* Otherwise, simply do as we didn't see the option.
	391	*/
	392	if (blksize >= 512) {
	393	option_name[nb_options] = "blksize";
	394	option_value[nb_options] = 512;
	395	nb_options++;
	396	}
1f697db9 TS	397	}
	398	}
	399
95b1ad7a HP	400	if (nb_options > 0) {
	401	assert(nb_options <= ARRAY_SIZE(option_name));
	402	tftp_send_oack(spt, option_name, option_value, nb_options, tp);
	403	return;
	404	}
	405
4aa401f3 HP	406	spt->block_nr = 0;
4aa401f3 HP	407	tftp_send_next_block(spt, tp);
c7f74643 FB	408	}
c7f74643 FB	409
fad7fb9c TH	410	static void tftp_handle_ack(Slirp slirp, struct sockaddr_storage srcsas,
fad7fb9c TH	411	struct tftp_t *tp, int pktlen)
c7f74643 FB	412	{
	413	int s;
	414
fad7fb9c	415	s = tftp_session_find(slirp, srcsas, tp);
c7f74643 FB	416
	417	if (s < 0) {
	418	return;
	419	}
	420
eb7faf0e	421	tftp_send_next_block(&slirp->tftp_sessions[s], tp);
c7f74643 FB	422	}
c7f74643 FB	423
fad7fb9c TH	424	static void tftp_handle_error(Slirp slirp, struct sockaddr_storage srcsas,
fad7fb9c TH	425	struct tftp_t *tp, int pktlen)
bfe4e172 TH	426	{
	427	int s;
	428
fad7fb9c	429	s = tftp_session_find(slirp, srcsas, tp);
bfe4e172 TH	430
	431	if (s < 0) {
	432	return;
	433	}
	434
	435	tftp_session_terminate(&slirp->tftp_sessions[s]);
	436	}
	437
fad7fb9c	438	void tftp_input(struct sockaddr_storage srcsas, struct mbuf m)
c7f74643 FB	439	{
	440	struct tftp_t tp = (struct tftp_t )m->m_data;
	441
	442	switch(ntohs(tp->tp_op)) {
	443	case TFTP_RRQ:
fad7fb9c	444	tftp_handle_rrq(m->slirp, srcsas, tp, m->m_len);
c7f74643 FB	445	break;
	446
	447	case TFTP_ACK:
fad7fb9c	448	tftp_handle_ack(m->slirp, srcsas, tp, m->m_len);
c7f74643	449	break;
bfe4e172 TH	450
bfe4e172 TH	451	case TFTP_ERROR:
fad7fb9c	452	tftp_handle_error(m->slirp, srcsas, tp, m->m_len);
bfe4e172	453	break;
c7f74643 FB	454	}
c7f74643 FB	455	}