1 files changed, 482 insertions, 0 deletions

diff --git a/src/hello/hello.c b/src/hello/hello.c
new file mode 100644
index 000000000..5a21bd41f
--- /dev/null
+++ b/src/hello/hello.c
@@ -0,0 +1,482 @@
+/*
+     This file is part of GNUnet.
+     (C) 2009 Christian Grothoff (and other contributing authors)
+
+     GNUnet is free software; you can redistribute it and/or modify
+     it under the terms of the GNU General Public License as published
+     by the Free Software Foundation; either version 2, 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
+     General Public License for more details.
+
+     You should have received a copy of the GNU General Public License
+     along with GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file hello/hello.c
+ * @brief helper library for handling HELLOs
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "gnunet_hello_lib.h"
+#include "gnunet_protocols.h"
+#include "gnunet_server_lib.h"
+
+/**
+ * A HELLO message is used to exchange information about
+ * transports with other peers.  This struct is always
+ * followed by the actual network addresses which have
+ * the format:
+ *
+ * 1) transport-name (0-terminated)
+ * 2) address-length (uint32_t, network byte order; possibly
+ *    unaligned!)
+ * 3) address expiration (GNUNET_TIME_AbsoluteNBO); possibly
+ *    unaligned!)
+ * 4) address (address-length bytes; possibly unaligned!)
+ */
+struct GNUNET_HELLO_Message
+{
+  /**
+   * Type will be GNUNET_MESSAGE_TYPE_HELLO.
+   */
+  struct GNUNET_MessageHeader header;
+
+  /**
+   * Always zero (for alignment).
+   */
+  uint32_t reserved GNUNET_PACKED;
+
+  /**
+   * The public key of the peer.
+   */
+  struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded publicKey;
+
+};
+
+
+/**
+ * Copy the given address information into
+ * the given buffer using the format of HELLOs.
+ *
+ * @param tname name of the transport plugin
+ * @param expiration expiration for the address
+ * @param addr the address
+ * @param addr_len length of the address in bytes
+ * @param target where to copy the address
+ * @param max maximum number of bytes to copy to target
+ * @return number of bytes copied, 0 if
+ *         the target buffer was not big enough.
+ */
+size_t
+GNUNET_HELLO_add_address (const char *tname,
+                          struct GNUNET_TIME_Absolute expiration,
+                          const void *addr,
+                          size_t addr_len, char *target, size_t max)
+{
+  uint32_t alen;
+  size_t slen;
+  struct GNUNET_TIME_AbsoluteNBO exp;
+
+  slen = strlen (tname) + 1;
+  if (slen + sizeof (uint32_t) + sizeof (struct GNUNET_TIME_AbsoluteNBO) +
+      addr_len > max)
+    return 0;
+  exp = GNUNET_TIME_absolute_hton (expiration);
+  alen = htonl ((uint32_t) addr_len);
+  memcpy (target, tname, slen);
+  memcpy (&target[slen], &alen, sizeof (uint32_t));
+  slen += sizeof (uint32_t);
+  memcpy (&target[slen], &exp, sizeof (struct GNUNET_TIME_AbsoluteNBO));
+  slen += sizeof (struct GNUNET_TIME_AbsoluteNBO);
+  memcpy (&target[slen], addr, addr_len);
+  slen += addr_len;
+  return slen;
+}
+
+
+/**
+ * Get the size of an address entry in a HELLO message.
+ *
+ * @param buf pointer to the start of the address entry
+ * @param max maximum size of the entry (end of buf)
+ * @param ralen set to the address length
+ * @return size of the entry, or 0 if max is not large enough
+ */
+static size_t
+get_hello_address_size (const char *buf, size_t max, uint32_t * ralen)
+{
+  const char *pos;
+  uint32_t alen;
+  size_t left;
+  size_t slen;
+
+  left = max;
+  pos = buf;
+  slen = 1;
+  while ((left > 0) && ('\0' != *pos))
+    {
+      left--;
+      pos++;
+      slen++;
+    }
+  if ('\0' != *pos)
+    {
+      /* 0-termination not found */
+      GNUNET_break_op (0);
+      return 0;
+    }
+  pos++;
+  if (left < sizeof (uint32_t) + sizeof (struct GNUNET_TIME_AbsoluteNBO))
+    {
+      /* not enough space for addrlen */
+      GNUNET_break_op (0);
+      return 0;
+    }
+  memcpy (&alen, pos, sizeof (uint32_t));
+  alen = ntohl (alen);
+  *ralen = alen;
+  slen += alen + sizeof (uint32_t) + sizeof (struct GNUNET_TIME_AbsoluteNBO);
+  if (max < slen)
+    {
+      /* not enough space for addr */
+      GNUNET_break_op (0);
+      return 0;
+    }
+  return slen;
+}
+
+
+/**
+ * Construct a HELLO message given the public key,
+ * expiration time and an iterator that spews the
+ * transport addresses.
+ *
+ * @return the hello message
+ */
+struct GNUNET_HELLO_Message *
+GNUNET_HELLO_create (const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
+                     *publicKey,
+                     GNUNET_HELLO_GenerateAddressListCallback addrgen,
+                     void *addrgen_cls)
+{
+  char buffer[GNUNET_SERVER_MAX_MESSAGE_SIZE - 256 -
+              sizeof (struct GNUNET_HELLO_Message)];
+  size_t max;
+  size_t used;
+  size_t ret;
+  struct GNUNET_HELLO_Message *hello;
+
+  max = sizeof (buffer);
+  used = 0;
+  while (0 != (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);
+  memcpy (&hello->publicKey, publicKey,
+          sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded));
+  memcpy (&hello[1], buffer, used);
+  return hello;
+}
+
+
+/**
+ * Iterate over all of the addresses in the HELLO.
+ *
+ * @param msg HELLO to iterate over
+ * @param return_modified if a modified copy should be returned,
+ *         otherwise NULL will be returned
+ * @param it iterator to call on each address
+ * @param it_cls closure for it
+ */
+struct GNUNET_HELLO_Message *
+GNUNET_HELLO_iterate_addresses (const struct GNUNET_HELLO_Message *msg,
+                                int return_modified,
+                                GNUNET_HELLO_AddressIterator it, void *it_cls)
+{
+  uint16_t msize;
+  struct GNUNET_HELLO_Message *ret;
+  const char *inptr;
+  size_t insize;
+  size_t esize;
+  size_t wpos;
+  char *woff;
+  uint32_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))
+    return NULL;
+  ret = NULL;
+  if (return_modified)
+    {
+      ret = GNUNET_malloc (msize);
+      memcpy (ret, msg, msize);
+    }
+  inptr = (const char *) &msg[1];
+  insize = msize - sizeof (struct GNUNET_HELLO_Message);
+  wpos = 0;
+  woff = (ret != NULL) ? (char *) &ret[1] : NULL;
+  while (insize > 0)
+    {
+      esize = get_hello_address_size (inptr, insize, &alen);
+      if (esize == 0)
+        {
+          GNUNET_break (0);
+          GNUNET_free_non_null (ret);
+          return NULL;
+        }
+      memcpy (&expire,
+              &inptr[esize - alen - sizeof (struct GNUNET_TIME_AbsoluteNBO)],
+              sizeof (struct GNUNET_TIME_AbsoluteNBO));
+      iret = it (it_cls,
+                 inptr,
+                 GNUNET_TIME_absolute_ntoh (expire),
+                 &inptr[esize - alen], alen);
+      if (iret == GNUNET_SYSERR)
+        {
+          if (ret != NULL)
+            ret->header.size =
+              ntohs (sizeof (struct GNUNET_HELLO_Message) + wpos);
+          return ret;
+        }
+      if ((iret == GNUNET_OK) && (ret != NULL))
+        {
+          memcpy (woff, inptr, esize);
+          woff += esize;
+          wpos += esize;
+        }
+      insize -= esize;
+      inptr += esize;
+    }
+  if (ret != NULL)
+    ret->header.size = ntohs (sizeof (struct GNUNET_HELLO_Message) + wpos);
+  return ret;
+}
+
+
+struct ExpireContext
+{
+  const void *addr;
+  size_t addrlen;
+  int found;
+  struct GNUNET_TIME_Absolute expiration;
+};
+
+
+static int
+get_match_exp (void *cls,
+               const char *tname,
+               struct GNUNET_TIME_Absolute expiration,
+               const void *addr, size_t addrlen)
+{
+  struct ExpireContext *ec = cls;
+
+  if ((addrlen == ec->addrlen) && (0 == memcmp (addr, ec->addr, addrlen)))
+    {
+      ec->found = GNUNET_YES;
+      ec->expiration = expiration;
+      return GNUNET_SYSERR;     /* done here */
+    }
+  return GNUNET_OK;
+}
+
+
+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 char *tname,
+             struct GNUNET_TIME_Absolute expiration,
+             const void *addr, size_t addrlen)
+{
+  struct MergeContext *mc = cls;
+  struct ExpireContext ec;
+
+  ec.addr = addr;
+  ec.addrlen = addrlen;
+  ec.found = GNUNET_NO;
+  GNUNET_HELLO_iterate_addresses (mc->other, GNUNET_NO, &get_match_exp, &ec);
+  if ((ec.found == GNUNET_NO) ||
+      ((ec.expiration.value < expiration.value) ||
+       ((ec.expiration.value == expiration.value) &&
+        (mc->take_equal == GNUNET_YES))))
+    mc->ret += GNUNET_HELLO_add_address (tname,
+                                         expiration,
+                                         addr,
+                                         addrlen,
+                                         &mc->buf[mc->ret],
+                                         mc->max - mc->ret);
+  return GNUNET_OK;
+}
+
+
+static size_t
+merge_addr (void *cls, size_t max, void *buf)
+{
+  struct MergeContext *mc = cls;
+
+  if (mc->h1 == NULL)
+    return 0;
+  mc->ret = 0;
+  mc->max = max;
+  mc->buf = buf;
+  mc->take_equal = GNUNET_NO;
+  mc->other = mc->h2;
+  GNUNET_HELLO_iterate_addresses (mc->h1, GNUNET_NO, &copy_latest, mc);
+  mc->take_equal = GNUNET_YES;
+  mc->other = mc->h1;
+  GNUNET_HELLO_iterate_addresses (mc->h2, GNUNET_NO, &copy_latest, mc);
+  mc->h1 = NULL;
+  return mc->ret;
+}
+
+
+/**
+ * Construct a HELLO message by merging the
+ * addresses in two existing HELLOs (which
+ * must be for the same peer).
+ *
+ * @param h1 first HELLO message
+ * @param h2 the second HELLO message
+ * @return the combined hello message
+ */
+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 };
+
+  return GNUNET_HELLO_create (&h1->publicKey, &merge_addr, &mc);
+}
+
+
+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 char *tname,
+             struct GNUNET_TIME_Absolute expiration,
+             const void *addr, size_t addrlen)
+{
+  struct DeltaContext *dc = cls;
+  int ret;
+  struct ExpireContext ec;
+
+  ec.addr = addr;
+  ec.addrlen = addrlen;
+  ec.found = GNUNET_NO;
+  GNUNET_HELLO_iterate_addresses (dc->old_hello,
+                                  GNUNET_NO, &get_match_exp, &ec);
+  if ((ec.found == GNUNET_YES) &&
+      ((ec.expiration.value > expiration.value) ||
+       (ec.expiration.value >= dc->expiration_limit.value)))
+    return GNUNET_YES;          /* skip */
+  ret = dc->it (dc->it_cls, tname, expiration, addr, addrlen);
+  return ret;
+}
+
+
+/**
+ * Iterate over addresses in "new_hello" that
+ * are NOT already present in "old_hello".
+ *
+ * @param new_hello a HELLO message
+ * @param old_hello a HELLO message
+ * @param expiration_limit ignore addresses in old_hello
+ *        that expired before the given time stamp
+ * @param it iterator to call on each address
+ * @param it_cls closure for it
+ */
+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_HELLO_iterate_addresses (new_hello, GNUNET_NO, &delta_match, &dc);
+}
+
+
+/**
+ * Return the size of the given HELLO message.
+ * @param hello to inspect
+ * @return the size, 0 if HELLO is invalid
+ */
+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;
+}
+
+
+/**
+ * Get the public key from a HELLO message.
+ *
+ * @param hello the hello message
+ * @param publicKey where to copy the public key information, can be NULL
+ * @return GNUNET_SYSERR if the HELLO was malformed
+ */
+int
+GNUNET_HELLO_get_key (const struct GNUNET_HELLO_Message *hello,
+                      struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
+                      *publicKey)
+{
+  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;
+  *publicKey = hello->publicKey;
+  return GNUNET_OK;
+}
+
+
+
+/* end of hello.c */