/**
* Force plugin to terminate session due to communication
* issue.
*
* @param plugin_name name of the plugin
* @param session session to termiante
*/
static void
kill_session (const char *plugin_name,
struct GNUNET_ATS_Session *session)
{
struct GNUNET_TRANSPORT_PluginFunctions *plugin;
struct GNUNET_ATS_SessionKiller *sk;
for (sk = sk_head; NULL != sk; sk = sk->next)
if (sk->session == session)
return;
plugin = GST_plugins_find (plugin_name);
if (NULL == plugin)
{
GNUNET_break(0);
return;
}
/* need to issue disconnect asynchronously */
sk = GNUNET_new (struct GNUNET_ATS_SessionKiller);
sk->session = session;
sk->plugin = plugin;
sk->task = GNUNET_SCHEDULER_add_now (&kill_session_task, sk);
GNUNET_CONTAINER_DLL_insert (sk_head,
sk_tail,
sk);
}
/**
* Send the given PONG to the given address.
*
* @param cls the PONG message
* @param public_key public key for the peer, never NULL
* @param valid_until is ZERO if we never validated the address,
* otherwise a time up to when we consider it (or was) valid
* @param validation_block is FOREVER if the address is for an unsupported plugin (from PEERINFO)
* is ZERO if the address is considered valid (no validation needed)
* otherwise a time in the future if we're currently denying re-validation
* @param address target address
*/
static void
multicast_pong (void *cls,
const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
*public_key, struct GNUNET_TIME_Absolute valid_until,
struct GNUNET_TIME_Absolute validation_block,
const struct GNUNET_HELLO_Address *address)
{
struct TransportPongMessage *pong = cls;
struct GNUNET_TRANSPORT_PluginFunctions *papi;
papi = GST_plugins_find (address->transport_name);
if (papi == NULL)
return;
GNUNET_assert (papi->send != NULL);
GNUNET_assert (papi->get_session != NULL);
struct Session * session = papi->get_session(papi->cls, address);
if (session == NULL)
{
GNUNET_break (0);
return;
}
papi->send (papi->cls, session,
(const char *) pong, ntohs (pong->header.size),
PONG_PRIORITY, ACCEPTABLE_PING_DELAY,
NULL, NULL);
}
/**
* Convert a given address to a human-readable format. Note that the
* return value will be overwritten on the next call to this function.
*
* @param address the address to convert
* @return statically allocated (!) human-readable address
*/
const char *
GST_plugins_a2s (const struct GNUNET_HELLO_Address *address)
{
struct GNUNET_TRANSPORT_PluginFunctions *api;
static char unable_to_show[1024];
if (address == NULL)
return "<inbound>";
api = GST_plugins_find (address->transport_name);
if (NULL == api)
return "<plugin unknown>";
if (0 == address->address_length)
{
GNUNET_snprintf (unable_to_show, sizeof (unable_to_show),
"<unable to stringify %u-byte long address of %s transport>",
(unsigned int) address->address_length,
address->transport_name);
return unable_to_show;
}
return api->address_to_string (NULL, address->address,
address->address_length);
}
/**
* We've received a PING. If appropriate, generate a PONG.
*
* @param sender peer sending the PING
* @param hdr the PING
* @param sender_address the sender address as we got it
* @param session session we got the PING from
*/
void
GST_validation_handle_ping (const struct GNUNET_PeerIdentity *sender,
const struct GNUNET_MessageHeader *hdr,
const struct GNUNET_HELLO_Address *sender_address,
struct Session *session)
{
const struct TransportPingMessage *ping;
struct TransportPongMessage *pong;
struct GNUNET_TRANSPORT_PluginFunctions *papi;
struct GNUNET_CRYPTO_RsaSignature *sig_cache;
struct GNUNET_TIME_Absolute *sig_cache_exp;
const char *addr;
const char *addrend;
size_t alen;
size_t slen;
ssize_t ret;
struct GNUNET_HELLO_Address address;
if (ntohs (hdr->size) < sizeof (struct TransportPingMessage))
{
GNUNET_break_op (0);
return;
}
ping = (const struct TransportPingMessage *) hdr;
if (0 !=
memcmp (&ping->target, &GST_my_identity,
sizeof (struct GNUNET_PeerIdentity)))
{
GNUNET_STATISTICS_update (GST_stats,
gettext_noop
("# PING message for different peer received"), 1,
GNUNET_NO);
return;
}
GNUNET_STATISTICS_update (GST_stats,
gettext_noop ("# PING messages received"), 1,
GNUNET_NO);
addr = (const char *) &ping[1];
alen = ntohs (hdr->size) - sizeof (struct TransportPingMessage);
/* peer wants to confirm that this is one of our addresses, this is what is
* used for address validation */
sig_cache = NULL;
sig_cache_exp = NULL;
if (0 < alen)
{
addrend = memchr (addr, '\0', alen);
if (NULL == addrend)
{
GNUNET_break_op (0);
return;
}
addrend++;
slen = strlen (addr) + 1;
alen -= slen;
address.address = addrend;
address.address_length = alen;
address.transport_name = addr;
address.peer = *sender;
if (GNUNET_YES !=
GST_hello_test_address (&address, &sig_cache, &sig_cache_exp))
{
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
_
("Not confirming PING with address `%s' since I cannot confirm having this address.\n"),
GST_plugins_a2s (&address));
return;
}
}
else
{
addrend = NULL; /* make gcc happy */
slen = 0;
static struct GNUNET_CRYPTO_RsaSignature no_address_signature;
static struct GNUNET_TIME_Absolute no_address_signature_expiration;
sig_cache = &no_address_signature;
sig_cache_exp = &no_address_signature_expiration;
}
pong = GNUNET_malloc (sizeof (struct TransportPongMessage) + alen + slen);
pong->header.size =
htons (sizeof (struct TransportPongMessage) + alen + slen);
pong->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_PONG);
pong->purpose.size =
htonl (sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose) +
sizeof (uint32_t) + sizeof (struct GNUNET_TIME_AbsoluteNBO) +
alen + slen);
pong->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_TRANSPORT_PONG_OWN);
pong->challenge = ping->challenge;
pong->addrlen = htonl (alen + slen);
memcpy (&pong[1], addr, slen);
memcpy (&((char *) &pong[1])[slen], addrend, alen);
if (GNUNET_TIME_absolute_get_remaining (*sig_cache_exp).rel_value <
PONG_SIGNATURE_LIFETIME.rel_value / 4)
{
/* create / update cached sig */
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Creating PONG signature to indicate ownership.\n");
*sig_cache_exp = GNUNET_TIME_relative_to_absolute (PONG_SIGNATURE_LIFETIME);
pong->expiration = GNUNET_TIME_absolute_hton (*sig_cache_exp);
GNUNET_assert (GNUNET_OK ==
GNUNET_CRYPTO_rsa_sign (GST_my_private_key, &pong->purpose,
sig_cache));
}
else
{
pong->expiration = GNUNET_TIME_absolute_hton (*sig_cache_exp);
}
pong->signature = *sig_cache;
GNUNET_assert (sender_address != NULL);
/* first see if the session we got this PING from can be used to transmit
* a response reliably */
papi = GST_plugins_find (sender_address->transport_name);
if (papi == NULL)
ret = -1;
else
{
GNUNET_assert (papi->send != NULL);
GNUNET_assert (papi->get_session != NULL);
if (session == NULL)
{
session = papi->get_session (papi->cls, sender_address);
}
if (session == NULL)
{
GNUNET_break (0);
ret = -1;
}
else
{
ret = papi->send (papi->cls, session,
(const char *) pong, ntohs (pong->header.size),
PONG_PRIORITY, ACCEPTABLE_PING_DELAY,
NULL, NULL);
}
}
if (ret != -1)
{
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Transmitted PONG to `%s' via reliable mechanism\n",
GNUNET_i2s (sender));
/* done! */
GNUNET_STATISTICS_update (GST_stats,
gettext_noop
("# PONGs unicast via reliable transport"), 1,
GNUNET_NO);
GNUNET_free (pong);
return;
}
/* no reliable method found, try transmission via all known addresses */
GNUNET_STATISTICS_update (GST_stats,
gettext_noop
("# PONGs multicast to all available addresses"), 1,
GNUNET_NO);
GST_validation_get_addresses (sender, &multicast_pong, pong);
GNUNET_free (pong);
}
/**
* Function called with the result from blacklisting.
* Send a PING to the other peer if a communication is allowed.
*
* @param cls our 'struct ValidationEntry'
* @param pid identity of the other peer
* @param result GNUNET_OK if the connection is allowed, GNUNET_NO if not
*/
static void
transmit_ping_if_allowed (void *cls, const struct GNUNET_PeerIdentity *pid,
int result)
{
struct ValidationEntry *ve = cls;
struct TransportPingMessage ping;
struct GNUNET_TRANSPORT_PluginFunctions *papi;
const struct GNUNET_MessageHeader *hello;
ssize_t ret;
size_t tsize;
size_t slen;
uint16_t hsize;
ve->bc = NULL;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transmitting plain PING to `%s' %s\n",
GNUNET_i2s (pid), GST_plugins_a2s (ve->address));
slen = strlen (ve->address->transport_name) + 1;
hello = GST_hello_get ();
hsize = ntohs (hello->size);
tsize =
sizeof (struct TransportPingMessage) + ve->address->address_length +
slen + hsize;
ping.header.size =
htons (sizeof (struct TransportPingMessage) +
ve->address->address_length + slen);
ping.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_PING);
ping.challenge = htonl (ve->challenge);
ping.target = *pid;
if (tsize >= GNUNET_SERVER_MAX_MESSAGE_SIZE)
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
_
("Not transmitting `%s' with `%s', message too big (%u bytes!). This should not happen.\n"),
"HELLO", "PING", (unsigned int) tsize);
/* message too big (!?), get rid of HELLO */
hsize = 0;
tsize =
sizeof (struct TransportPingMessage) + ve->address->address_length +
slen + hsize;
}
{
char message_buf[tsize];
/* build message with structure:
* [HELLO][TransportPingMessage][Transport name][Address] */
memcpy (message_buf, hello, hsize);
memcpy (&message_buf[hsize], &ping, sizeof (struct TransportPingMessage));
memcpy (&message_buf[sizeof (struct TransportPingMessage) + hsize],
ve->address->transport_name, slen);
memcpy (&message_buf[sizeof (struct TransportPingMessage) + slen + hsize],
ve->address, ve->address->address_length);
papi = GST_plugins_find (ve->address->transport_name);
if (papi == NULL)
ret = -1;
else
{
GNUNET_assert (papi->send != NULL);
GNUNET_assert (papi->get_session != NULL);
struct Session * session = papi->get_session(papi->cls, ve->address);
if (session != NULL)
{
ret = papi->send (papi->cls, session,
message_buf, tsize,
PING_PRIORITY, ACCEPTABLE_PING_DELAY,
NULL, NULL);
}
else
{
/* Could not get a valid session */
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Could not get a valid session for `%s' %s\n",
GNUNET_i2s (pid), GST_plugins_a2s (ve->address));
ret = -1;
}
}
}
if (-1 != ret)
{
ve->send_time = GNUNET_TIME_absolute_get ();
GNUNET_STATISTICS_update (GST_stats,
gettext_noop
("# PING without HELLO messages sent"), 1,
GNUNET_NO);
ve->expecting_pong = GNUNET_YES;
}
}
