1 files changed, 834 insertions, 0 deletions

diff --git a/src/util/regex.c b/src/util/regex.c
new file mode 100644
index 000000000..7565a9eac
--- /dev/null
+++ b/src/util/regex.c
@@ -0,0 +1,834 @@
+/*
+     This file is part of GNUnet
+     Copyright (C) 2012, 2013, 2015 GNUnet e.V.
+
+     GNUnet is free software: you can redistribute it and/or modify it
+     under the terms of the GNU Affero General Public License as published
+     by the Free Software Foundation, either version 3 of the License,
+     or (at your option) any later version.
+
+     GNUnet is distributed in the hope that it will be useful, but
+     WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+     Affero General Public License for more details.
+    
+     You should have received a copy of the GNU Affero General Public License
+     along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * @file src/tun/regex.c
+ * @brief functions to convert IP networks to regexes
+ * @author Maximilian Szengel
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_tun_lib.h"
+
+/**
+ * 'wildcard', matches all possible values (for HEX encoding).
+ */
+#define DOT "(0|1|2|3|4|5|6|7|8|9|A|B|C|D|E|F)"
+
+
+/**
+ * Create a regex in @a rxstr from the given @a ip and @a netmask.
+ *
+ * @param ip IPv4 representation.
+ * @param port destination port
+ * @param rxstr generated regex, must be at least #GNUNET_TUN_IPV4_REGEXLEN
+ *              bytes long.
+ */
+void
+GNUNET_TUN_ipv4toregexsearch (const struct in_addr *ip,
+                              uint16_t port,
+                              char *rxstr)
+{
+  GNUNET_snprintf (rxstr,
+                   GNUNET_TUN_IPV4_REGEXLEN,
+                   "4-%04X-%08X",
+                   (unsigned int) port,
+                   ntohl (ip->s_addr));
+}
+
+
+/**
+ * Create a regex in @a rxstr from the given @a ipv6 and @a prefixlen.
+ *
+ * @param ipv6 IPv6 representation.
+ * @param port destination port
+ * @param rxstr generated regex, must be at least #GNUNET_TUN_IPV6_REGEXLEN
+ *              bytes long.
+ */
+void
+GNUNET_TUN_ipv6toregexsearch (const struct in6_addr *ipv6,
+                              uint16_t port,
+                              char *rxstr)
+{
+  const uint32_t *addr;
+
+  addr = (const uint32_t *) ipv6;
+  GNUNET_snprintf (rxstr,
+                   GNUNET_TUN_IPV6_REGEXLEN,
+                   "6-%04X-%08X%08X%08X%08X",
+                   (unsigned int) port,
+                   ntohl (addr[0]),
+                   ntohl (addr[1]),
+                   ntohl (addr[2]),
+                   ntohl (addr[3]));
+}
+
+
+/**
+ * Convert the given 4-bit (!) number to a regex.
+ *
+ * @param value the value, only the lowest 4 bits will be looked at
+ * @param mask which bits in value are wildcards (any value)?
+ */
+static char *
+nibble_to_regex (uint8_t value,
+                 uint8_t mask)
+{
+  char *ret;
+
+  value &= mask;
+  switch (mask)
+  {
+  case 0:
+    return GNUNET_strdup (DOT);
+  case 8:
+    GNUNET_asprintf (&ret,
+                     "(%X|%X|%X|%X|%X|%X|%X|%X)",
+                     value,
+                     value + 1,
+                     value + 2,
+                     value + 3,
+                     value + 4,
+                     value + 5,
+                     value + 6,
+                     value + 7);
+    return ret;
+  case 12:
+    GNUNET_asprintf (&ret,
+                     "(%X|%X|%X|%X)",
+                     value,
+                     value + 1,
+                     value + 2,
+                     value + 3);
+    return ret;
+  case 14:
+    GNUNET_asprintf (&ret,
+                     "(%X|%X)",
+                     value,
+                     value + 1);
+    return ret;
+  case 15:
+    GNUNET_asprintf (&ret,
+                     "%X",
+                     value);
+    return ret;
+  default:
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                _("Bad mask: %d\n"),
+                mask);
+    GNUNET_break (0);
+    return NULL;
+  }
+}
+
+
+/**
+ * Convert the given 16-bit number to a regex.
+ *
+ * @param value the value
+ * @param mask which bits in value are wildcards (any value)?
+ */
+static char *
+num_to_regex (uint16_t value,
+              uint16_t mask)
+{
+  const uint8_t *v = (const uint8_t *) &value;
+  const uint8_t *m = (const uint8_t *) &mask;
+  char *a;
+  char *b;
+  char *c;
+  char *d;
+  char *ret;
+
+  a = nibble_to_regex (v[0] >> 4, m[0] >> 4);
+  b = nibble_to_regex (v[0] & 15, m[0] & 15);
+  c = nibble_to_regex (v[1] >> 4, m[1] >> 4);
+  d = nibble_to_regex (v[1] & 15, m[1] & 15);
+  ret = NULL;
+  if ( (NULL != a) &&
+       (NULL != b) &&
+       (NULL != c) &&
+       (NULL != d) )
+    GNUNET_asprintf (&ret,
+                     "%s%s%s%s",
+                     a, b, c, d);
+  GNUNET_free_non_null (a);
+  GNUNET_free_non_null (b);
+  GNUNET_free_non_null (c);
+  GNUNET_free_non_null (d);
+  return ret;
+}
+
+
+/**
+ * Do we need to put parents around the given argument?
+ *
+ * @param arg part of a regular expression
+ * @return #GNUNET_YES if we should parens,
+ *         #GNUNET_NO if not
+ */
+static int
+needs_parens (const char *arg)
+{
+  size_t off;
+  size_t len;
+  unsigned int op;
+
+  op = 0;
+  len = strlen (arg);
+  for (off=0;off<len;off++)
+  {
+    switch (arg[off])
+    {
+    case '(':
+      op++;
+      break;
+    case ')':
+      GNUNET_assert (op > 0);
+      op--;
+      break;
+    case '|':
+      if (0 == op)
+        return GNUNET_YES;
+      break;
+    default:
+      break;
+    }
+  }
+  return GNUNET_NO;
+}
+
+
+/**
+ * Compute port policy for the given range of
+ * port numbers.
+ *
+ * @param start starting offset
+ * @param end end offset
+ * @param step increment level (power of 16)
+ * @param pp port policy to convert
+ * @return corresponding regex
+ */
+static char *
+compute_policy (unsigned int start,
+                unsigned int end,
+                unsigned int step,
+                const struct GNUNET_STRINGS_PortPolicy *pp)
+{
+  unsigned int i;
+  char before[36]; /* 16 * 2 + 3 dots + 0-terminator */
+  char middlel[33]; /* 16 * 2 + 0-terminator */
+  char middleh[33]; /* 16 * 2 + 0-terminator */
+  char after[36]; /* 16 * 2 + 3 dots + 0-terminator */
+  char beforep[36+2]; /* 16 * 2 + 3 dots + 0-terminator + ()*/
+  char middlehp[33+2]; /* 16 * 2 + 0-terminator + () */
+  char middlelp[33+2]; /* 16 * 2 + 0-terminator + () */
+  char afterp[36+2]; /* 16 * 2 + 3 dots + 0-terminator + () */
+  char dots[5 * strlen (DOT)];
+  char buf[3];
+  char *middle;
+  char *ret;
+  unsigned int xstep;
+  char *recl;
+  char *rech;
+  char *reclp;
+  char *rechp;
+  unsigned int start_port;
+  unsigned int end_port;
+
+  GNUNET_assert (GNUNET_YES == pp->negate_portrange);
+  start_port = pp->start_port;
+  if (1 == start_port)
+    start_port = 0;
+  end_port = pp->end_port;
+  GNUNET_assert ((end - start) / step <= 0xF);
+  before[0] = '\0';
+  middlel[0] = '\0';
+  middleh[0] = '\0';
+  after[0] = '\0';
+  for (i=start;i<=end;i+=step)
+  {
+    GNUNET_snprintf (buf,
+                     sizeof (buf),
+                     "%X|",
+                     (i - start) / step);
+    if (i / step < start_port / step)
+      strcat (before, buf);
+    else if (i / step > end_port / step)
+      strcat (after, buf);
+    else if (i / step == start_port / step)
+      strcat (middlel, buf);
+    else if (i / step == end_port / step)
+      strcat (middleh, buf);
+  }
+  if (strlen (before) > 0)
+    before[strlen (before)-1] = '\0';
+  if (strlen (middlel) > 0)
+    middlel[strlen (middlel)-1] = '\0';
+  if (strlen (middleh) > 0)
+    middleh[strlen (middleh)-1] = '\0';
+  if (strlen (after) > 0)
+    after[strlen (after)-1] = '\0';
+  if (needs_parens (before))
+    GNUNET_snprintf (beforep,
+                     sizeof (beforep),
+                     "(%s)",
+                     before);
+  else
+    strcpy (beforep, before);
+  if (needs_parens (middlel))
+    GNUNET_snprintf (middlelp,
+                     sizeof (middlelp),
+                     "(%s)",
+                     middlel);
+  else
+    strcpy (middlelp, middlel);
+  if (needs_parens (middleh))
+    GNUNET_snprintf (middlehp,
+                     sizeof (middlehp),
+                     "(%s)",
+                     middleh);
+  else
+    strcpy (middlehp, middleh);
+  if (needs_parens (after))
+    GNUNET_snprintf (afterp,
+                     sizeof (afterp),
+                     "(%s)",
+                     after);
+  else
+    strcpy (afterp, after);
+  dots[0] = '\0';
+  for (xstep=step/16;xstep>0;xstep/=16)
+    strcat (dots, DOT);
+  if (step >= 16)
+  {
+    if (strlen (middlel) > 0)
+      recl = compute_policy ((start_port / step) * step,
+                             (start_port / step) * step + step - 1,
+                             step / 16,
+                             pp);
+    else
+      recl = GNUNET_strdup ("");
+    if (strlen (middleh) > 0)
+      rech = compute_policy ((end_port / step) * step,
+                             (end_port / step) * step + step - 1,
+                             step / 16,
+                             pp);
+    else
+      rech = GNUNET_strdup ("");
+  }
+  else
+  {
+    recl = GNUNET_strdup ("");
+    rech = GNUNET_strdup ("");
+    middlel[0] = '\0';
+    middlelp[0] = '\0';
+    middleh[0] = '\0';
+    middlehp[0] = '\0';
+  }
+  if (needs_parens (recl))
+    GNUNET_asprintf (&reclp,
+                     "(%s)",
+                     recl);
+  else
+    reclp = GNUNET_strdup (recl);
+  if (needs_parens (rech))
+    GNUNET_asprintf (&rechp,
+                     "(%s)",
+                     rech);
+  else
+    rechp = GNUNET_strdup (rech);
+
+  if ( (strlen (middleh) > 0) &&
+       (strlen (rech) > 0) &&
+       (strlen (middlel) > 0) &&
+       (strlen (recl) > 0) )
+  {
+    GNUNET_asprintf (&middle,
+                     "%s%s|%s%s",
+                     middlel,
+                     reclp,
+                     middleh,
+                     rechp);
+  }
+  else if ( (strlen (middleh) > 0) &&
+            (strlen (rech) > 0) )
+  {
+    GNUNET_asprintf (&middle,
+                     "%s%s",
+                     middleh,
+                     rechp);
+  }
+  else if ( (strlen (middlel) > 0) &&
+            (strlen (recl) > 0) )
+  {
+    GNUNET_asprintf (&middle,
+                     "%s%s",
+                     middlel,
+                     reclp);
+  }
+  else
+  {
+    middle = GNUNET_strdup ("");
+  }
+  if ( (strlen(before) > 0) &&
+       (strlen(after) > 0) )
+  {
+    if (strlen (dots) > 0)
+    {
+      if (strlen (middle) > 0)
+        GNUNET_asprintf (&ret,
+                         "(%s%s|%s|%s%s)",
+                         beforep, dots,
+                         middle,
+                         afterp, dots);
+      else
+        GNUNET_asprintf (&ret,
+                         "(%s|%s)%s",
+                         beforep,
+                         afterp,
+                         dots);
+    }
+    else
+    {
+      if (strlen (middle) > 0)
+        GNUNET_asprintf (&ret,
+                         "(%s|%s|%s)",
+                         before,
+                         middle,
+                         after);
+      else if (1 == step)
+        GNUNET_asprintf (&ret,
+                         "%s|%s",
+                         before,
+                         after);
+      else
+        GNUNET_asprintf (&ret,
+                         "(%s|%s)",
+                         before,
+                         after);
+    }
+  }
+  else if (strlen (before) > 0)
+  {
+    if (strlen (dots) > 0)
+    {
+      if (strlen (middle) > 0)
+        GNUNET_asprintf (&ret,
+                         "(%s%s|%s)",
+                         beforep, dots,
+                         middle);
+      else
+        GNUNET_asprintf (&ret,
+                         "%s%s",
+                         beforep, dots);
+    }
+    else
+    {
+      if (strlen (middle) > 0)
+        GNUNET_asprintf (&ret,
+                         "(%s|%s)",
+                         before,
+                         middle);
+      else
+        GNUNET_asprintf (&ret,
+                         "%s",
+                         before);
+    }
+  }
+  else if (strlen (after) > 0)
+  {
+    if (strlen (dots) > 0)
+    {
+      if (strlen (middle) > 0)
+        GNUNET_asprintf (&ret,
+                         "(%s|%s%s)",
+                         middle,
+                         afterp, dots);
+      else
+        GNUNET_asprintf (&ret,
+                         "%s%s",
+                         afterp, dots);
+    }
+    else
+    {
+      if (strlen (middle) > 0)
+        GNUNET_asprintf (&ret,
+                         "%s|%s",
+                         middle,
+                         after);
+      else
+        GNUNET_asprintf (&ret,
+                         "%s",
+                         after);
+    }
+  }
+  else if (strlen (middle) > 0)
+  {
+    GNUNET_asprintf (&ret,
+                     "%s",
+                     middle);
+  }
+  else
+  {
+    ret = GNUNET_strdup ("");
+  }
+  GNUNET_free (middle);
+  GNUNET_free (reclp);
+  GNUNET_free (rechp);
+  GNUNET_free (recl);
+  GNUNET_free (rech);
+  return ret;
+}
+
+
+/**
+ * Convert a port policy to a regular expression.  Note: this is a
+ * very simplistic implementation, we might want to consider doing
+ * something more sophisiticated (resulting in smaller regular
+ * expressions) at a later time.
+ *
+ * @param pp port policy to convert
+ * @return NULL on error
+ */
+static char *
+port_to_regex (const struct GNUNET_STRINGS_PortPolicy *pp)
+{
+  char *reg;
+  char *ret;
+  char *pos;
+  unsigned int i;
+  unsigned int cnt;
+
+  if ( (0 == pp->start_port) ||
+       ( (1 == pp->start_port) &&
+         (0xFFFF == pp->end_port) &&
+         (GNUNET_NO == pp->negate_portrange)) )
+    return GNUNET_strdup (DOT DOT DOT DOT);
+  if ( (pp->start_port == pp->end_port) &&
+       (GNUNET_NO == pp->negate_portrange))
+  {
+    GNUNET_asprintf (&ret,
+                     "%04X",
+                     pp->start_port);
+    return ret;
+  }
+  if (pp->end_port < pp->start_port)
+    return NULL;
+
+  if (GNUNET_YES == pp->negate_portrange)
+  {
+    ret = compute_policy (0, 0xFFFF, 0x1000, pp);
+  }
+  else
+  {
+    cnt = pp->end_port - pp->start_port + 1;
+    reg = GNUNET_malloc (cnt * 5 + 1);
+    pos = reg;
+    for (i=1;i<=0xFFFF;i++)
+    {
+      if ( (i >= pp->start_port) && (i <= pp->end_port) )
+      {
+        if (pos == reg)
+        {
+          GNUNET_snprintf (pos,
+                           5,
+                           "%04X",
+                           i);
+        }
+        else
+        {
+          GNUNET_snprintf (pos,
+                           6,
+                           "|%04X",
+                           i);
+        }
+        pos += strlen (pos);
+      }
+    }
+    GNUNET_asprintf (&ret,
+                     "(%s)",
+                     reg);
+    GNUNET_free (reg);
+  }
+  return ret;
+}
+
+
+/**
+ * Convert an address (IPv4 or IPv6) to a regex.
+ *
+ * @param addr address
+ * @param mask network mask
+ * @param len number of bytes in @a addr and @a mask
+ * @return NULL on error, otherwise regex for the address
+ */
+static char *
+address_to_regex (const void *addr,
+                  const void *mask,
+                  size_t len)
+{
+  const uint16_t *a = addr;
+  const uint16_t *m = mask;
+  char *ret;
+  char *tmp;
+  char *reg;
+  unsigned int i;
+
+  ret = NULL;
+  GNUNET_assert (1 != (len % 2));
+  for (i=0;i<len / 2;i++)
+  {
+    reg = num_to_regex (a[i], m[i]);
+    if (NULL == reg)
+    {
+      GNUNET_free_non_null (ret);
+      return NULL;
+    }
+    if (NULL == ret)
+    {
+      ret = reg;
+    }
+    else
+    {
+      GNUNET_asprintf (&tmp,
+                       "%s%s",
+                       ret, reg);
+      GNUNET_free (ret);
+      GNUNET_free (reg);
+      ret = tmp;
+    }
+  }
+  return ret;
+}
+
+
+/**
+ * Convert a single line of an IPv4 policy to a regular expression.
+ *
+ * @param v4 line to convert
+ * @return NULL on error
+ */
+static char *
+ipv4_to_regex (const struct GNUNET_STRINGS_IPv4NetworkPolicy *v4)
+{
+  char *reg;
+  char *pp;
+  char *ret;
+
+  reg = address_to_regex (&v4->network,
+                          &v4->netmask,
+                          sizeof (struct in_addr));
+  if (NULL == reg)
+    return NULL;
+  pp = port_to_regex (&v4->pp);
+  if (NULL == pp)
+  {
+    GNUNET_free (reg);
+    return NULL;
+  }
+  GNUNET_asprintf (&ret,
+                   "4-%s-%s",
+                   pp, reg);
+  GNUNET_free (pp);
+  GNUNET_free (reg);
+  return ret;
+}
+
+
+/**
+ * Convert a single line of an IPv4 policy to a regular expression.
+ *
+ * @param v6 line to convert
+ * @return NULL on error
+ */
+static char *
+ipv6_to_regex (const struct GNUNET_STRINGS_IPv6NetworkPolicy *v6)
+{
+  char *reg;
+  char *pp;
+  char *ret;
+
+  reg = address_to_regex (&v6->network,
+                          &v6->netmask,
+                          sizeof (struct in6_addr));
+  if (NULL == reg)
+    return NULL;
+  pp = port_to_regex (&v6->pp);
+  if (NULL == pp)
+  {
+    GNUNET_free (reg);
+    return NULL;
+  }
+  GNUNET_asprintf (&ret,
+                   "6-%s-%s",
+                   pp, reg);
+  GNUNET_free (pp);
+  GNUNET_free (reg);
+  return ret;
+}
+
+
+/**
+ * Convert an exit policy to a regular expression.  The exit policy
+ * specifies a set of subnets this peer is willing to serve as an
+ * exit for; the resulting regular expression will match the
+ * IPv4 address strings as returned by #GNUNET_TUN_ipv4toregexsearch().
+ *
+ * @param policy exit policy specification
+ * @return regular expression, NULL on error
+ */
+char *
+GNUNET_TUN_ipv4policy2regex (const char *policy)
+{
+  struct GNUNET_STRINGS_IPv4NetworkPolicy *np;
+  char *reg;
+  char *tmp;
+  char *line;
+  unsigned int i;
+
+  np = GNUNET_STRINGS_parse_ipv4_policy (policy);
+  if (NULL == np)
+    return NULL;
+  reg = NULL;
+  for (i=0; (0 == i) || (0 != np[i].network.s_addr); i++)
+  {
+    line = ipv4_to_regex (&np[i]);
+    if (NULL == line)
+    {
+      GNUNET_free_non_null (reg);
+      GNUNET_free (np);
+      return NULL;
+    }
+    if (NULL == reg)
+    {
+      reg = line;
+    }
+    else
+    {
+      GNUNET_asprintf (&tmp,
+                       "%s|(%s)",
+                       reg, line);
+      GNUNET_free (reg);
+      GNUNET_free (line);
+      reg = tmp;
+    }
+    if (0 == np[i].network.s_addr)
+      break;
+  }
+  GNUNET_free (np);
+  return reg;
+}
+
+
+/**
+ * Convert an exit policy to a regular expression.  The exit policy
+ * specifies a set of subnets this peer is willing to serve as an
+ * exit for; the resulting regular expression will match the
+ * IPv6 address strings as returned by #GNUNET_TUN_ipv6toregexsearch().
+ *
+ * @param policy exit policy specification
+ * @return regular expression, NULL on error
+ */
+char *
+GNUNET_TUN_ipv6policy2regex (const char *policy)
+{
+  struct in6_addr zero;
+  struct GNUNET_STRINGS_IPv6NetworkPolicy *np;
+  char *reg;
+  char *tmp;
+  char *line;
+  unsigned int i;
+
+  np = GNUNET_STRINGS_parse_ipv6_policy (policy);
+  if (NULL == np)
+    return NULL;
+  reg = NULL;
+  memset (&zero, 0, sizeof (struct in6_addr));
+  for (i=0; (0 == i) || (0 != memcmp (&zero, &np[i].network, sizeof (struct in6_addr))); i++)
+  {
+    line = ipv6_to_regex (&np[i]);
+    if (NULL == line)
+    {
+      GNUNET_free_non_null (reg);
+      GNUNET_free (np);
+      return NULL;
+    }
+    if (NULL == reg)
+    {
+      reg = line;
+    }
+    else
+    {
+      GNUNET_asprintf (&tmp,
+                       "%s|(%s)",
+                       reg, line);
+      GNUNET_free (reg);
+      GNUNET_free (line);
+      reg = tmp;
+    }
+    if (0 == memcmp (&zero, &np[i].network, sizeof (struct in6_addr)))
+      break;
+  }
+  GNUNET_free (np);
+  return reg;
+}
+
+
+/**
+ * Hash the service name of a hosted service to the
+ * hash code that is used to identify the service on
+ * the network.
+ *
+ * @param service_name a string
+ * @param hc corresponding hash
+ */
+void
+GNUNET_TUN_service_name_to_hash (const char *service_name,
+                                 struct GNUNET_HashCode *hc)
+{
+  GNUNET_CRYPTO_hash (service_name,
+                      strlen (service_name),
+                      hc);
+}
+
+
+/**
+ * Compute the CADET port given a service descriptor
+ * (returned from #GNUNET_TUN_service_name_to_hash) and
+ * a TCP/UDP port @a ip_port.
+ *
+ * @param desc service shared secret
+ * @param ip_port TCP/UDP port, use 0 for ICMP
+ * @param[out] cadet_port CADET port to use
+ */
+void
+GNUNET_TUN_compute_service_cadet_port (const struct GNUNET_HashCode *desc,
+                                       uint16_t ip_port,
+                                       struct GNUNET_HashCode *cadet_port)
+{
+  uint16_t be_port = htons (ip_port);
+
+  *cadet_port = *desc;
+  GNUNET_memcpy (cadet_port,
+                 &be_port,
+                 sizeof (uint16_t));
+}
+
+
+/* end of regex.c */