hello.c

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/*
     This file is part of GNUnet.
     Copyright (C) 2009, 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/>.
 
     SPDX-License-Identifier: AGPL3.0-or-later
 */
 
#include "platform.h"
#include "gnunet_hello_lib.h"
#include "gnunet_protocols.h"
#include "gnunet_util_lib.h"
#include "gnunet_transport_plugin.h"
 
struct GNUNET_HELLO_ComposeUriContext
{
  char *uri;
 
  GNUNET_HELLO_TransportPluginsFind plugins_find;
};
 
 
struct GNUNET_HELLO_ParseUriContext
{
  const char *pos;
 
  int ret;
 
  unsigned int counter_total;
 
  unsigned int counter_added;
 
  GNUNET_HELLO_TransportPluginsFind plugins_find;
};
 
 
int
GNUNET_HELLO_is_friend_only (const struct GNUNET_HELLO_Message *h)
{
  if (GNUNET_YES == ntohl (h->friend_only))
    return GNUNET_YES;
  return GNUNET_NO;
}
 
 
size_t
GNUNET_HELLO_add_address (const struct GNUNET_HELLO_Address *address,
                          struct GNUNET_TIME_Absolute expiration,
                          char *target,
                          size_t max)
{
  uint16_t alen;
  size_t slen;
  struct GNUNET_TIME_AbsoluteNBO exp;
 
  slen = strlen (address->transport_name) + 1;
  if (slen + sizeof(uint16_t) + sizeof(struct GNUNET_TIME_AbsoluteNBO)
      + address->address_length > max)
    return 0;
  exp = GNUNET_TIME_absolute_hton (expiration);
  alen = htons ((uint16_t) address->address_length);
  GNUNET_memcpy (target, address->transport_name, slen);
  GNUNET_memcpy (&target[slen], &alen, sizeof(uint16_t));
  slen += sizeof(uint16_t);
  GNUNET_memcpy (&target[slen], &exp, sizeof(struct GNUNET_TIME_AbsoluteNBO));
  slen += sizeof(struct GNUNET_TIME_AbsoluteNBO);
  GNUNET_memcpy (&target[slen], address->address, address->address_length);
  slen += address->address_length;
  return slen;
}
 
 
static size_t
get_hello_address_size (const char *buf,
                        size_t max,
                        uint16_t *ralen)
{
  const char *pos;
  uint16_t alen;
  size_t left;
  size_t slen;
 
  left = max;
  pos = buf;
  slen = 1;
  while ((left > 0) && ('\0' != *pos))
  {
    left--;
    pos++;
    slen++;
  }
  if (0 == left)
  {
    /* 0-termination not found */
    GNUNET_break_op (0);
    return 0;
  }
  pos++;
  if (left < sizeof(uint16_t) + sizeof(struct GNUNET_TIME_AbsoluteNBO))
  {
    /* not enough space for addrlen */
    GNUNET_break_op (0);
    return 0;
  }
  GNUNET_memcpy (&alen, pos, sizeof(uint16_t));
  alen = ntohs (alen);
  *ralen = alen;
  slen += alen + sizeof(uint16_t) + sizeof(struct GNUNET_TIME_AbsoluteNBO);
  if (max < slen)
  {
    /* not enough space for addr */
    GNUNET_break_op (0);
    return 0;
  }
  return slen;
}
 
 
struct GNUNET_HELLO_Message *
GNUNET_HELLO_create (const struct GNUNET_CRYPTO_EddsaPublicKey *public_key,
                     GNUNET_HELLO_GenerateAddressListCallback addrgen,
                     void *addrgen_cls,
                     int friend_only)
{
  char buffer[GNUNET_MAX_MESSAGE_SIZE - 1 - 256
              - sizeof(struct GNUNET_HELLO_Message)];
  size_t max;
  size_t used;
  size_t ret;
  struct GNUNET_HELLO_Message *hello;
 
  GNUNET_assert (NULL != public_key);
  GNUNET_assert ((GNUNET_YES == friend_only) ||
                 (GNUNET_NO == friend_only));
  max = sizeof(buffer);
  used = 0;
  if (NULL != addrgen)
  {
    while (GNUNET_SYSERR != (ret = addrgen (addrgen_cls,
                                            max,
                                            &buffer[used])))
    {
      max -= ret;
      used += ret;
    }
  }
  hello = GNUNET_malloc (sizeof(struct GNUNET_HELLO_Message) + used);
  hello->header.type = htons (GNUNET_MESSAGE_TYPE_HELLO);
  hello->header.size = htons (sizeof(struct GNUNET_HELLO_Message) + used);
  hello->friend_only = htonl (friend_only);
  hello->publicKey = *public_key;
  GNUNET_memcpy (&hello[1],
                 buffer,
                 used);
  return hello;
}
 
 
struct GNUNET_HELLO_Message *
GNUNET_HELLO_iterate_addresses (const struct GNUNET_HELLO_Message *msg,
                                int return_modified,
                                GNUNET_HELLO_AddressIterator it,
                                void *it_cls)
{
  struct GNUNET_HELLO_Address address;
  uint16_t msize;
  struct GNUNET_HELLO_Message *ret;
  const char *inptr;
  size_t insize;
  size_t esize;
  size_t wpos;
  char *woff;
  uint16_t alen;
  struct GNUNET_TIME_AbsoluteNBO expire;
  int iret;
 
  msize = GNUNET_HELLO_size (msg);
  if ((msize < sizeof(struct GNUNET_HELLO_Message)) ||
      (ntohs (msg->header.type) != GNUNET_MESSAGE_TYPE_HELLO))
  {
    GNUNET_break_op (0);
    return NULL;
  }
  ret = NULL;
  if (return_modified)
  {
    ret = GNUNET_malloc (msize);
    GNUNET_memcpy (ret,
                   msg,
                   msize);
  }
  inptr = (const char *) &msg[1];
  insize = msize - sizeof(struct GNUNET_HELLO_Message);
  wpos = 0;
  woff = (NULL != ret) ? (char *) &ret[1] : NULL;
  address.peer.public_key = msg->publicKey;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "HELLO has %u bytes of address data\n",
              (unsigned int) insize);
 
  while (insize > 0)
  {
    esize = get_hello_address_size (inptr,
                                    insize,
                                    &alen);
    if (0 == esize)
    {
      GNUNET_break (0);
      GNUNET_free (ret);
      return NULL;
    }
    /* need GNUNET_memcpy() due to possibility of misalignment */
    GNUNET_memcpy (&expire,
                   &inptr[esize - alen - sizeof(struct
                                                GNUNET_TIME_AbsoluteNBO)],
                   sizeof(struct GNUNET_TIME_AbsoluteNBO));
    address.address = &inptr[esize - alen];
    address.address_length = alen;
    address.transport_name = inptr;
    address.local_info = GNUNET_HELLO_ADDRESS_INFO_NONE;
    iret = it (it_cls,
               &address,
               GNUNET_TIME_absolute_ntoh (expire));
    if (GNUNET_SYSERR == iret)
      break;
    if ((GNUNET_OK == iret) &&
        (NULL != ret))
    {
      /* copy address over */
      GNUNET_memcpy (woff,
                     inptr,
                     esize);
      woff += esize;
      wpos += esize;
    }
    insize -= esize;
    inptr += esize;
  }
  if (NULL != ret)
    ret->header.size = ntohs (sizeof(struct GNUNET_HELLO_Message) + wpos);
  return ret;
}
 
 
struct ExpireContext
{
  const struct GNUNET_HELLO_Address *address;
 
  int found;
 
  struct GNUNET_TIME_Absolute expiration;
};
 
 
static int
get_match_exp (void *cls,
               const struct GNUNET_HELLO_Address *address,
               struct GNUNET_TIME_Absolute expiration)
{
  struct ExpireContext *ec = cls;
 
  if (0 != GNUNET_HELLO_address_cmp (address,
                                     ec->address))
    return GNUNET_OK;
  ec->found = GNUNET_YES;
  ec->expiration = expiration;
  return GNUNET_SYSERR;       /* done here */
}
 
 
struct MergeContext
{
  const struct GNUNET_HELLO_Message *h1;
 
  const struct GNUNET_HELLO_Message *h2;
 
  const struct GNUNET_HELLO_Message *other;
 
  char *buf;
 
  size_t max;
 
  size_t ret;
 
  int take_equal;
};
 
 
static int
copy_latest (void *cls,
             const struct GNUNET_HELLO_Address *address,
             struct GNUNET_TIME_Absolute expiration)
{
  struct MergeContext *mc = cls;
  struct ExpireContext ec;
 
  ec.address = address;
  ec.found = GNUNET_NO;
  /* check if address exists in other */
  GNUNET_HELLO_iterate_addresses (mc->other,
                                  GNUNET_NO,
                                  &get_match_exp,
                                  &ec);
  if ((GNUNET_NO == ec.found) ||
      (ec.expiration.abs_value_us < expiration.abs_value_us) ||
      ((ec.expiration.abs_value_us == expiration.abs_value_us) &&
       (GNUNET_YES == mc->take_equal)))
  {
    /* copy address to buffer */
    mc->ret +=
      GNUNET_HELLO_add_address (address,
                                expiration,
                                &mc->buf[mc->ret],
                                mc->max - mc->ret);
  }
  return GNUNET_OK;
}
 
 
static ssize_t
merge_addr (void *cls,
            size_t max,
            void *buf)
{
  struct MergeContext *mc = cls;
 
  if (NULL == mc->h1)
    return GNUNET_SYSERR; /* Stop iteration */
  mc->ret = 0;
  mc->max = max;
  mc->buf = buf;
  mc->take_equal = GNUNET_NO;
  mc->other = mc->h2;
  /* copy addresses from h1, if strictly larger expiration than h2 */
  GNUNET_HELLO_iterate_addresses (mc->h1,
                                  GNUNET_NO,
                                  &copy_latest,
                                  mc);
  mc->take_equal = GNUNET_YES;
  mc->other = mc->h1;
  /* copy addresses from h2, if larger or equal expiration than h1 */
  GNUNET_HELLO_iterate_addresses (mc->h2,
                                  GNUNET_NO,
                                  &copy_latest,
                                  mc);
  /* set marker to stop iteration */
  mc->h1 = NULL;
  return mc->ret;
}
 
 
struct GNUNET_HELLO_Message *
GNUNET_HELLO_merge (const struct GNUNET_HELLO_Message *h1,
                    const struct GNUNET_HELLO_Message *h2)
{
  struct MergeContext mc = { h1, h2, NULL, NULL, 0, 0, 0 };
  int friend_only;
 
  if (h1->friend_only != h2->friend_only)
    friend_only = GNUNET_YES; /* One of the HELLOs is friend only */
  else
    friend_only = ntohl (h1->friend_only); /* Both HELLO's have the same type */
 
  return GNUNET_HELLO_create (&h1->publicKey,
                              &merge_addr,
                              &mc,
                              friend_only);
}
 
 
struct DeltaContext
{
  struct GNUNET_TIME_Absolute expiration_limit;
 
  GNUNET_HELLO_AddressIterator it;
 
  void *it_cls;
 
  const struct GNUNET_HELLO_Message *old_hello;
};
 
 
static int
delta_match (void *cls,
             const struct GNUNET_HELLO_Address *address,
             struct GNUNET_TIME_Absolute expiration)
{
  struct DeltaContext *dc = cls;
  int ret;
  struct ExpireContext ec;
 
  ec.address = address;
  ec.found = GNUNET_NO;
  GNUNET_HELLO_iterate_addresses (dc->old_hello,
                                  GNUNET_NO,
                                  &get_match_exp,
                                  &ec);
  if ((GNUNET_YES == ec.found) &&
      ((ec.expiration.abs_value_us > expiration.abs_value_us) ||
       (ec.expiration.abs_value_us >= dc->expiration_limit.abs_value_us)))
    return GNUNET_YES;          /* skip: found and boring */
  ret = dc->it (dc->it_cls,
                address,
                expiration);
  return ret;
}
 
 
void
GNUNET_HELLO_iterate_new_addresses (const struct
                                    GNUNET_HELLO_Message *new_hello,
                                    const struct
                                    GNUNET_HELLO_Message *old_hello,
                                    struct GNUNET_TIME_Absolute
                                    expiration_limit,
                                    GNUNET_HELLO_AddressIterator it,
                                    void *it_cls)
{
  struct DeltaContext dc;
 
  dc.expiration_limit = expiration_limit;
  dc.it = it;
  dc.it_cls = it_cls;
  dc.old_hello = old_hello;
  GNUNET_assert (NULL ==
                 GNUNET_HELLO_iterate_addresses (new_hello,
                                                 GNUNET_NO,
                                                 &delta_match,
                                                 &dc));
}
 
 
uint16_t
GNUNET_HELLO_size (const struct GNUNET_HELLO_Message *hello)
{
  uint16_t ret = ntohs (hello->header.size);
 
  if ((ret < sizeof(struct GNUNET_HELLO_Message)) ||
      (ntohs (hello->header.type) != GNUNET_MESSAGE_TYPE_HELLO))
    return 0;
  return ret;
}
 
 
int
GNUNET_HELLO_get_id (const struct GNUNET_HELLO_Message *hello,
                     struct GNUNET_PeerIdentity *peer)
{
  uint16_t ret = ntohs (hello->header.size);
 
  if ((ret < sizeof(struct GNUNET_HELLO_Message)) ||
      (ntohs (hello->header.type) != GNUNET_MESSAGE_TYPE_HELLO))
    return GNUNET_SYSERR;
  peer->public_key = hello->publicKey;
  return GNUNET_OK;
}
 
 
struct GNUNET_MessageHeader *
GNUNET_HELLO_get_header (struct GNUNET_HELLO_Message *hello)
{
  uint16_t ret = ntohs (hello->header.size);
 
  if ((ret < sizeof(struct GNUNET_HELLO_Message)) ||
      (ntohs (hello->header.type) != GNUNET_MESSAGE_TYPE_HELLO))
    return NULL;
 
  return &hello->header;
}
 
 
struct EqualsContext
{
  struct GNUNET_TIME_Absolute expiration_limit;
 
  struct GNUNET_TIME_Absolute result;
 
  const struct GNUNET_HELLO_Message *ref;
 
  const struct GNUNET_HELLO_Address *address;
 
  struct GNUNET_TIME_Absolute expiration;
 
  int found;
};
 
 
static int
find_other_matching (void *cls,
                     const struct GNUNET_HELLO_Address *address,
                     struct GNUNET_TIME_Absolute expiration)
{
  struct EqualsContext *ec = cls;
 
  if (expiration.abs_value_us < ec->expiration_limit.abs_value_us)
    return GNUNET_YES;
  if (0 == GNUNET_HELLO_address_cmp (address, ec->address))
  {
    ec->found = GNUNET_YES;
    if (expiration.abs_value_us < ec->expiration.abs_value_us)
      ec->result = GNUNET_TIME_absolute_min (expiration,
                                             ec->result);
    return GNUNET_SYSERR;
  }
  return GNUNET_YES;
}
 
 
static int
find_matching (void *cls,
               const struct GNUNET_HELLO_Address *address,
               struct GNUNET_TIME_Absolute expiration)
{
  struct EqualsContext *ec = cls;
 
  if (expiration.abs_value_us < ec->expiration_limit.abs_value_us)
    return GNUNET_OK; /* expired, we don't care */
  ec->address = address;
  ec->expiration = expiration;
  ec->found = GNUNET_NO;
  GNUNET_HELLO_iterate_addresses (ec->ref,
                                  GNUNET_NO,
                                  &find_other_matching,
                                  ec);
  if (GNUNET_NO == ec->found)
  {
    /* not found, we differ *now* */
    ec->result = GNUNET_TIME_UNIT_ZERO_ABS;
    return GNUNET_SYSERR;
  }
  return GNUNET_OK;
}
 
 
struct GNUNET_TIME_Absolute
GNUNET_HELLO_equals (const struct GNUNET_HELLO_Message *h1,
                     const struct GNUNET_HELLO_Message *h2,
                     struct GNUNET_TIME_Absolute now)
{
  struct EqualsContext ec;
 
  if (h1->header.type != h2->header.type)
    return GNUNET_TIME_UNIT_ZERO_ABS;
  if (0 !=
      GNUNET_memcmp (&h1->publicKey,
                     &h2->publicKey))
    return GNUNET_TIME_UNIT_ZERO_ABS;
  ec.expiration_limit = now;
  ec.result = GNUNET_TIME_UNIT_FOREVER_ABS;
  ec.ref = h2;
  GNUNET_HELLO_iterate_addresses (h1,
                                  GNUNET_NO,
                                  &find_matching,
                                  &ec);
  if (ec.result.abs_value_us == GNUNET_TIME_UNIT_ZERO.rel_value_us)
    return ec.result;
  ec.ref = h1;
  GNUNET_HELLO_iterate_addresses (h2,
                                  GNUNET_NO,
                                  &find_matching,
                                  &ec);
  return ec.result;
}
 
 
static int
find_max_expire (void *cls,
                 const struct GNUNET_HELLO_Address *address,
                 struct GNUNET_TIME_Absolute expiration)
{
  struct GNUNET_TIME_Absolute *max = cls;
 
  *max = GNUNET_TIME_absolute_max (*max, expiration);
  return GNUNET_OK;
}
 
 
struct GNUNET_TIME_Absolute
GNUNET_HELLO_get_last_expiration (const struct GNUNET_HELLO_Message *msg)
{
  struct GNUNET_TIME_Absolute ret;
 
  ret = GNUNET_TIME_UNIT_ZERO_ABS;
  GNUNET_HELLO_iterate_addresses (msg,
                                  GNUNET_NO,
                                  &find_max_expire,
                                  &ret);
  return ret;
}
 
 
static int
add_address_to_uri (void *cls,
                    const struct GNUNET_HELLO_Address *address,
                    struct GNUNET_TIME_Absolute expiration)
{
  struct GNUNET_HELLO_ComposeUriContext *ctx = cls;
  struct GNUNET_TRANSPORT_PluginFunctions *papi;
  const char *addr;
  char *ret;
  char *addr_dup;
  char *pos;
  char tbuf[16] = "";
  char *client_str = "_client";
  struct tm *t;
  time_t seconds;
 
  papi = ctx->plugins_find (address->transport_name);
  if (NULL == papi)
  {
    /* Not an error - we might just not have the right plugin. */
    return GNUNET_OK;
  }
  if (NULL == papi->address_to_string)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "URI conversion not implemented for plugin `%s'\n",
                address->transport_name);
    return GNUNET_OK;
  }
  addr = papi->address_to_string (papi->cls,
                                  address->address,
                                  address->address_length);
  if ((NULL == addr) ||
      (0 == strlen (addr)))
    return GNUNET_OK;
 
  addr_dup = GNUNET_strdup (addr);
  if (NULL != (pos = strstr (addr_dup, "_server")))
    GNUNET_memcpy (pos,
                   client_str,
                   strlen (client_str)); /* Replace all server addresses with client addresses */
 
  seconds = expiration.abs_value_us / 1000LL / 1000LL;
  t = gmtime (&seconds);
 
  GNUNET_asprintf (&ret,
                   "%s%c%s%c%s%c%s",
                   ctx->uri,
                   GNUNET_HELLO_URI_SEP,
                   strftime (tbuf,
                             sizeof(tbuf),
                             "%Y%m%d%H%M%S",
                             t) ? tbuf : "0",
                   GNUNET_HELLO_URI_SEP,
                   address->transport_name,
                   GNUNET_HELLO_URI_SEP,
                   addr_dup);
  GNUNET_free (addr_dup);
  GNUNET_free (ctx->uri);
  ctx->uri = ret;
  return GNUNET_OK;
}
 
 
char *
GNUNET_HELLO_compose_uri (const struct GNUNET_HELLO_Message *hello,
                          GNUNET_HELLO_TransportPluginsFind plugins_find)
{
  struct GNUNET_HELLO_ComposeUriContext ctx;
  char *pkey;
 
  ctx.plugins_find = plugins_find;
  pkey = GNUNET_CRYPTO_eddsa_public_key_to_string (&hello->publicKey);
  GNUNET_asprintf (&ctx.uri,
                   "%s%s",
                   (GNUNET_YES == GNUNET_HELLO_is_friend_only (hello))
                   ? GNUNET_FRIEND_HELLO_URI_PREFIX
                   : GNUNET_HELLO_URI_PREFIX,
                   pkey);
  GNUNET_free (pkey);
  GNUNET_HELLO_iterate_addresses (hello,
                                  GNUNET_NO,
                                  &add_address_to_uri,
                                  &ctx);
  return ctx.uri;
}
 
 
/* ************************* Parse HELLO URI ********************* */
 
 
static ssize_t
add_address_to_hello (void *cls,
                      size_t max,
                      void *buffer)
{
  struct GNUNET_HELLO_ParseUriContext *ctx = cls;
  const char *tname;
  const char *address;
  char *uri_address;
  const char *end;
  char *plugin_name;
  struct tm expiration_time;
  time_t expiration_seconds;
  struct GNUNET_TIME_Absolute expire;
  struct GNUNET_TRANSPORT_PluginFunctions *papi;
  void *addr;
  size_t addr_len;
  struct GNUNET_HELLO_Address haddr;
  ssize_t ret;
 
  if (NULL == ctx->pos)
    return GNUNET_SYSERR;
  if (GNUNET_HELLO_URI_SEP != ctx->pos[0])
  {
    ctx->ret = GNUNET_SYSERR;
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  ctx->pos++;
 
  if (('0' == ctx->pos[0]) &&
      (GNUNET_HELLO_URI_SEP == ctx->pos[1]))
  {
    expire = GNUNET_TIME_UNIT_FOREVER_ABS;
    tname = ctx->pos + 1;
  }
  else
  {
    memset (&expiration_time, 0, sizeof(expiration_time));
    tname = strptime (ctx->pos,
                      "%Y%m%d%H%M%S",
                      &expiration_time);
    if (NULL == tname)
    {
      ctx->ret = GNUNET_SYSERR;
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  _ (
                    "Failed to parse HELLO message: missing expiration time\n"));
      GNUNET_break (0);
      return GNUNET_SYSERR;
    }
 
    expiration_seconds = mktime (&expiration_time);
    if (expiration_seconds == (time_t) -1)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  _ (
                    "Failed to parse HELLO message: invalid expiration time\n"));
      ctx->ret = GNUNET_SYSERR;
      GNUNET_break (0);
      return GNUNET_SYSERR;
    }
    expire.abs_value_us = expiration_seconds * 1000LL * 1000LL;
  }
  if (GNUNET_HELLO_URI_SEP != tname[0])
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                _ ("Failed to parse HELLO message: malformed\n"));
    ctx->ret = GNUNET_SYSERR;
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  tname++;
  address = strchr (tname,
                    (int) GNUNET_HELLO_URI_SEP);
  if (NULL == address)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                _ (
                  "Failed to parse HELLO message: missing transport plugin\n"));
    ctx->ret = GNUNET_SYSERR;
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  address++;
  end = strchr (address, (int) GNUNET_HELLO_URI_SEP);
  ctx->pos = end;
  ctx->counter_total++;
  plugin_name = GNUNET_strndup (tname, address - (tname + 1));
  papi = ctx->plugins_find (plugin_name);
  if (NULL == papi)
  {
    /* Not an error - we might just not have the right plugin.
     * Skip this part, advance to the next one and recurse.
     * But only if this is not the end of string.
     */
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                _ ("Plugin `%s' not found, skipping address\n"),
                plugin_name);
    GNUNET_free (plugin_name);
    return 0;
  }
  if (NULL == papi->string_to_address)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                _ ("Plugin `%s' does not support URIs yet\n"),
                plugin_name);
    GNUNET_free (plugin_name);
    GNUNET_break (0);
    return 0;
  }
  uri_address = GNUNET_strndup (address, end - address);
  if (GNUNET_OK !=
      papi->string_to_address (papi->cls,
                               uri_address,
                               strlen (uri_address) + 1,
                               &addr,
                               &addr_len))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                _ ("Failed to parse `%s' as an address for plugin `%s'\n"),
                uri_address,
                plugin_name);
    GNUNET_free (plugin_name);
    GNUNET_free (uri_address);
    return 0;
  }
  GNUNET_free (uri_address);
  /* address.peer is unset - not used by add_address() */
  haddr.address_length = addr_len;
  haddr.address = addr;
  haddr.transport_name = plugin_name;
  ret = GNUNET_HELLO_add_address (&haddr,
                                  expire,
                                  buffer,
                                  max);
  ctx->counter_added++;
  GNUNET_free (addr);
  GNUNET_free (plugin_name);
  return ret;
}
 
 
int
GNUNET_HELLO_parse_uri (const char *uri,
                        struct GNUNET_CRYPTO_EddsaPublicKey *pubkey,
                        struct GNUNET_HELLO_Message **hello,
                        GNUNET_HELLO_TransportPluginsFind plugins_find)
{
  const char *pks;
  const char *exc;
  int friend_only;
  struct GNUNET_HELLO_ParseUriContext ctx;
 
  if (0 == strncmp (uri,
                    GNUNET_HELLO_URI_PREFIX,
                    strlen (GNUNET_HELLO_URI_PREFIX)))
  {
    pks = &uri[strlen (GNUNET_HELLO_URI_PREFIX)];
    friend_only = GNUNET_NO;
  }
  else if (0 == strncmp (uri,
                         GNUNET_FRIEND_HELLO_URI_PREFIX,
                         strlen (GNUNET_FRIEND_HELLO_URI_PREFIX)))
  {
    pks = &uri[strlen (GNUNET_FRIEND_HELLO_URI_PREFIX)];
    friend_only = GNUNET_YES;
  }
  else
    return GNUNET_SYSERR;
  exc = strchr (pks, GNUNET_HELLO_URI_SEP);
 
  if (GNUNET_OK !=
      GNUNET_STRINGS_string_to_data (pks,
                                     (NULL == exc) ? strlen (pks) : (exc - pks),
                                     (unsigned char *) pubkey,
                                     sizeof(*pubkey)))
    return GNUNET_SYSERR;
 
  ctx.pos = exc;
  ctx.ret = GNUNET_OK;
  ctx.counter_total = 0;
  ctx.counter_added = 0;
  ctx.plugins_find = plugins_find;
  *hello = GNUNET_HELLO_create (pubkey,
                                &add_address_to_hello,
                                &ctx,
                                friend_only);
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "HELLO URI contained %u addresses, added %u addresses\n",
              ctx.counter_total,
              ctx.counter_added);
 
  return ctx.ret;
}
 
 
/* end of hello.c */