1 files changed, 442 insertions, 0 deletions

diff --git a/slirp/tftp.c b/slirp/tftp.c
new file mode 100644
index 00000000..a329fb28
--- /dev/null
+++ b/slirp/tftp.c
@@ -0,0 +1,442 @@
+/*
+ * 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>
+#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];
+
+  /* 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 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;
+  }
+}