/* This file is part of GNUnet. (C) 2012, 2013 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 3, 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 multicast/multicast_api.c * @brief multicast service; establish tunnels to distant peers * @author Christian Grothoff * @author Gabor X Toth */ #include "platform.h" #include "gnunet_util_lib.h" #include "gnunet_signatures.h" #include "gnunet_multicast_service.h" #include "multicast.h" #define LOG(kind,...) GNUNET_log_from (kind, "multicast-api",__VA_ARGS__) /** * Handle for a request to send a message to all multicast group members * (from the origin). */ struct GNUNET_MULTICAST_OriginMessageHandle { GNUNET_MULTICAST_OriginTransmitNotify notify; void *notify_cls; struct GNUNET_MULTICAST_Origin *origin; uint64_t message_id; uint64_t group_generation; uint64_t fragment_offset; }; /** * Handle for the origin of a multicast group. */ struct GNUNET_MULTICAST_Origin { struct GNUNET_CRYPTO_EddsaPrivateKey priv_key; struct GNUNET_MULTICAST_OriginMessageHandle msg_handle; GNUNET_MULTICAST_JoinCallback join_cb; GNUNET_MULTICAST_MembershipTestCallback mem_test_cb; GNUNET_MULTICAST_ReplayFragmentCallback replay_frag_cb; GNUNET_MULTICAST_ReplayMessageCallback replay_msg_cb; GNUNET_MULTICAST_RequestCallback request_cb; GNUNET_MULTICAST_MessageCallback message_cb; void *cls; uint64_t next_fragment_id; }; /** * Handle for a message to be delivered from a member to the origin. */ struct GNUNET_MULTICAST_MemberRequestHandle { }; /** * Opaque handle for a multicast group member. */ struct GNUNET_MULTICAST_Member { }; GNUNET_NETWORK_STRUCT_BEGIN /** * Header of a request from a member to the origin. */ struct GNUNET_MULTICAST_RequestHeader { /** * Header for all requests from a member to the origin. */ struct GNUNET_MessageHeader header; /** * Public key of the sending member. */ struct GNUNET_CRYPTO_EddsaPublicKey member_key; /** * ECC signature of the request fragment. * * Signature must match the public key of the multicast group. */ struct GNUNET_CRYPTO_EddsaSignature signature; /** * Purpose for the signature and size of the signed data. */ struct GNUNET_CRYPTO_EccSignaturePurpose purpose; /** * Number of the request fragment, monotonically increasing. */ uint64_t fragment_id GNUNET_PACKED; /** * Byte offset of this @e fragment of the @e request. */ uint64_t fragment_offset GNUNET_PACKED; /** * Number of the request this fragment belongs to. * * Set in GNUNET_MULTICAST_origin_to_all(). */ uint64_t request_id GNUNET_PACKED; /** * Flags for this request. */ enum GNUNET_MULTICAST_MessageFlags flags GNUNET_PACKED; /* Followed by request body. */ }; /** * Header of a join request sent to the origin or another member. */ struct GNUNET_MULTICAST_JoinRequest { /** * Header for the join request. */ struct GNUNET_MessageHeader header; /** * ECC signature of the rest of the fields of the join request. * * Signature must match the public key of the joining member. */ struct GNUNET_CRYPTO_EddsaSignature signature; /** * Purpose for the signature and size of the signed data. */ struct GNUNET_CRYPTO_EccSignaturePurpose purpose; /** * Public key of the target group. */ struct GNUNET_CRYPTO_EddsaPublicKey group_key; /** * Public key of the joining member. */ struct GNUNET_CRYPTO_EddsaPublicKey member_key; /** * Peer identity of the joining member. */ struct GNUNET_PeerIdentity member_peer; /* Followed by request body. */ }; GNUNET_NETWORK_STRUCT_END /** * Handle that identifies a join request. * * Used to match calls to #GNUNET_MULTICAST_JoinCallback to the * corresponding calls to #GNUNET_MULTICAST_join_decision(). */ struct GNUNET_MULTICAST_JoinHandle { }; /** * Function to call with the decision made for a join request. * * Must be called once and only once in response to an invocation of the * #GNUNET_MULTICAST_JoinCallback. * * @param jh Join request handle. * @param is_admitted #GNUNET_YES if joining is approved, * #GNUNET_NO if it is disapproved * @param relay_count Number of relays given. * @param relays Array of suggested peers that might be useful relays to use * when joining the multicast group (essentially a list of peers that * are already part of the multicast group and might thus be willing * to help with routing). If empty, only this local peer (which must * be the multicast origin) is a good candidate for building the * multicast tree. Note that it is unnecessary to specify our own * peer identity in this array. * @param join_response Message to send in response to the joining peer; * can also be used to redirect the peer to a different group at the * application layer; this response is to be transmitted to the * peer that issued the request even if admission is denied. */ struct GNUNET_MULTICAST_ReplayHandle * GNUNET_MULTICAST_join_decision (struct GNUNET_MULTICAST_JoinHandle *jh, int is_admitted, unsigned int relay_count, const struct GNUNET_PeerIdentity *relays, const struct GNUNET_MessageHeader *join_response) { return NULL; } /** * Handle to pass back for the answer of a membership test. */ struct GNUNET_MULTICAST_MembershipTestHandle { }; /** * Call informing multicast about the decision taken for a membership test. * * @param mth Handle that was given for the query. * @param result #GNUNET_YES if peer was a member, #GNUNET_NO if peer was not a member, * #GNUNET_SYSERR if we cannot answer the membership test. */ void GNUNET_MULTICAST_membership_test_result (struct GNUNET_MULTICAST_MembershipTestHandle *mth, int result) { } /** * Opaque handle to a replay request from the multicast service. */ struct GNUNET_MULTICAST_ReplayHandle { }; /** * Replay a message fragment for the multicast group. * * @param rh Replay handle identifying which replay operation was requested. * @param msg Replayed message fragment, NULL if unknown/error. * @param ec Error code. */ void GNUNET_MULTICAST_replay_response (struct GNUNET_MULTICAST_ReplayHandle *rh, const struct GNUNET_MessageHeader *msg, enum GNUNET_MULTICAST_ReplayErrorCode ec) { } /** * Indicate the end of the replay session. * * Invalidates the replay handle. * * @param rh Replay session to end. */ void GNUNET_MULTICAST_replay_response_end (struct GNUNET_MULTICAST_ReplayHandle *rh) { } /** * Replay a message for the multicast group. * * @param rh Replay handle identifying which replay operation was requested. * @param notify Function to call to get the message. * @param notify_cls Closure for @a notify. */ void GNUNET_MULTICAST_replay_response2 (struct GNUNET_MULTICAST_ReplayHandle *rh, GNUNET_MULTICAST_ReplayTransmitNotify notify, void *notify_cls) { } /** * Start a multicast group. * * Will advertise the origin in the P2P overlay network under the respective * public key so that other peer can find this peer to join it. Peers that * issue GNUNET_MULTICAST_member_join() can then transmit a join request to * either an existing group member or to the origin. If the joining is * approved, the member is cleared for @e replay and will begin to receive * messages transmitted to the group. If joining is disapproved, the failed * candidate will be given a response. Members in the group can send messages * to the origin (one at a time). * * @param cfg Configuration to use. * @param priv_key ECC key that will be used to sign messages for this * multicast session; public key is used to identify the multicast group; * @param next_fragment_id Next fragment ID to continue counting fragments from * when restarting the origin. 0 for a new group. * @param join_cb Function called to approve / disapprove joining of a peer. * @param mem_test_cb Function multicast can use to test group membership. * @param replay_frag_cb Function that can be called to replay a message fragment. * @param replay_msg_cb Function that can be called to replay a message. * @param request_cb Function called with message fragments from group members. * @param message_cb Function called with the message fragments sent to the * network by GNUNET_MULTICAST_origin_to_all(). These message fragments * should be stored for answering replay requests later. * @param cls Closure for the various callbacks that follow. * @return Handle for the origin, NULL on error. */ struct GNUNET_MULTICAST_Origin * GNUNET_MULTICAST_origin_start (const struct GNUNET_CONFIGURATION_Handle *cfg, const struct GNUNET_CRYPTO_EddsaPrivateKey *priv_key, uint64_t next_fragment_id, GNUNET_MULTICAST_JoinCallback join_cb, GNUNET_MULTICAST_MembershipTestCallback mem_test_cb, GNUNET_MULTICAST_ReplayFragmentCallback replay_frag_cb, GNUNET_MULTICAST_ReplayMessageCallback replay_msg_cb, GNUNET_MULTICAST_RequestCallback request_cb, GNUNET_MULTICAST_MessageCallback message_cb, void *cls) { struct GNUNET_MULTICAST_Origin *orig = GNUNET_malloc (sizeof (*orig)); orig->priv_key = *priv_key; orig->next_fragment_id = next_fragment_id; orig->join_cb = join_cb; orig->mem_test_cb = mem_test_cb; orig->replay_frag_cb = replay_frag_cb; orig->replay_msg_cb = replay_msg_cb; orig->request_cb = request_cb; orig->message_cb = message_cb; orig->cls = cls; return orig; } /* FIXME: for now just send back to the client what it sent. */ static void schedule_origin_to_all (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { LOG (GNUNET_ERROR_TYPE_DEBUG, "schedule_origin_to_all()\n"); struct GNUNET_MULTICAST_Origin *orig = cls; struct GNUNET_MULTICAST_OriginMessageHandle *mh = &orig->msg_handle; size_t buf_size = GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD; char buf[GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD] = ""; struct GNUNET_MULTICAST_MessageHeader *msg = (struct GNUNET_MULTICAST_MessageHeader *) buf; int ret = mh->notify (mh->notify_cls, &buf_size, &msg[1]); if (! (GNUNET_YES == ret || GNUNET_NO == ret) || GNUNET_MULTICAST_FRAGMENT_MAX_PAYLOAD < buf_size) { LOG (GNUNET_ERROR_TYPE_ERROR, "MasterTransmitNotify() returned error or invalid message size.\n"); /* FIXME: handle error */ return; } if (GNUNET_NO == ret && 0 == buf_size) return; /* Transmission paused. */ msg->header.type = htons (GNUNET_MESSAGE_TYPE_MULTICAST_MESSAGE); msg->header.size = htons (sizeof (*msg) + buf_size); msg->message_id = GNUNET_htonll (mh->message_id); msg->group_generation = mh->group_generation; /* FIXME: add fragment ID and signature in the service instead of here */ msg->fragment_id = GNUNET_ntohll (orig->next_fragment_id++); msg->fragment_offset = GNUNET_ntohll (mh->fragment_offset); mh->fragment_offset += sizeof (*msg) + buf_size; msg->purpose.size = htonl (sizeof (*msg) + buf_size - sizeof (msg->header) - sizeof (msg->hop_counter) - sizeof (msg->signature)); msg->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_MULTICAST_MESSAGE); if (GNUNET_OK != GNUNET_CRYPTO_eddsa_sign (&orig->priv_key, &msg->purpose, &msg->signature)) { /* FIXME: handle error */ return; } /* FIXME: send msg to the service and only then call message_cb with the * returned signed message. * FIXME: Also send to local members in this group. */ orig->message_cb (orig->cls, (const struct GNUNET_MessageHeader *) msg); if (GNUNET_NO == ret) GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 1), schedule_origin_to_all, orig); } /** * Send a message to the multicast group. * * @param origin Handle to the multicast group. * @param message_id Application layer ID for the message. Opaque to multicast. * @param group_generation Group generation of the message. Documented in * `struct GNUNET_MULTICAST_MessageHeader`. * @param notify Function to call to get the message. * @param notify_cls Closure for @a notify. * @return NULL on error (i.e. request already pending). */ struct GNUNET_MULTICAST_OriginMessageHandle * GNUNET_MULTICAST_origin_to_all (struct GNUNET_MULTICAST_Origin *origin, uint64_t message_id, uint64_t group_generation, GNUNET_MULTICAST_OriginTransmitNotify notify, void *notify_cls) { struct GNUNET_MULTICAST_OriginMessageHandle *mh = &origin->msg_handle; mh->origin = origin; mh->message_id = message_id; mh->group_generation = group_generation; mh->notify = notify; mh->notify_cls = notify_cls; GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 1), schedule_origin_to_all, origin); return &origin->msg_handle; } /** * Resume message transmission to multicast group. * * @param mh Request to cancel. */ void GNUNET_MULTICAST_origin_to_all_resume (struct GNUNET_MULTICAST_OriginMessageHandle *mh) { GNUNET_SCHEDULER_add_now (schedule_origin_to_all, mh->origin); } /** * Cancel request for message transmission to multicast group. * * @param mh Request to cancel. */ void GNUNET_MULTICAST_origin_to_all_cancel (struct GNUNET_MULTICAST_OriginMessageHandle *mh) { } /** * Stop a multicast group. * * @param origin Multicast group to stop. */ void GNUNET_MULTICAST_origin_stop (struct GNUNET_MULTICAST_Origin *origin) { GNUNET_free (origin); } /** * Join a multicast group. * * The entity joining is always the local peer. Further information about the * candidate can be provided in the @a join_request message. If the join fails, the * @a message_cb is invoked with a (failure) response and then with NULL. If * the join succeeds, outstanding (state) messages and ongoing multicast * messages will be given to the @a message_cb until the member decides to part * the group. The @a test_cb and @a replay_cb functions may be called at * anytime by the multicast service to support relaying messages to other * members of the group. * * @param cfg Configuration to use. * @param group_key ECC public key that identifies the group to join. * @param member_key ECC key that identifies the member and used to sign * requests sent to the origin. * @param origin Peer ID of the origin to send unicast requsets to. If NULL, * unicast requests are sent back via multiple hops on the reverse path * of multicast messages. * @param relay_count Number of peers in the @a relays array. * @param relays Peer identities of members of the group, which serve as relays * and can be used to join the group at. and send the @a join_request to. * If empty, the @a join_request is sent directly to the @a origin. * @param join_request Application-dependent join request to be passed to the peer * @a relay (might, for example, contain a user, bind user * identity/pseudonym to peer identity, application-level message to * origin, etc.). * @param join_cb Function called to approve / disapprove joining of a peer. * @param mem_test_cb Function multicast can use to test group membership. * @param replay_frag_cb Function that can be called to replay message fragments * this peer already knows from this group. NULL if this * client is unable to support replay. * @param replay_msg_cb Function that can be called to replay message fragments * this peer already knows from this group. NULL if this * client is unable to support replay. * @param message_cb Function to be called for all message fragments we * receive from the group, excluding those our @a replay_cb * already has. * @param cls Closure for callbacks. * @return Handle for the member, NULL on error. */ struct GNUNET_MULTICAST_Member * GNUNET_MULTICAST_member_join (const struct GNUNET_CONFIGURATION_Handle *cfg, const struct GNUNET_CRYPTO_EddsaPublicKey *group_key, const struct GNUNET_CRYPTO_EddsaPrivateKey *member_key, const struct GNUNET_PeerIdentity *origin, uint32_t relay_count, const struct GNUNET_PeerIdentity *relays, const struct GNUNET_MessageHeader *join_request, GNUNET_MULTICAST_JoinCallback join_cb, GNUNET_MULTICAST_MembershipTestCallback mem_test_cb, GNUNET_MULTICAST_ReplayFragmentCallback replay_frag_cb, GNUNET_MULTICAST_ReplayMessageCallback replay_msg_cb, GNUNET_MULTICAST_MessageCallback message_cb, void *cls) { struct GNUNET_MULTICAST_Member *mem = GNUNET_malloc (sizeof (*mem)); return mem; } /** * Handle for a replay request. */ struct GNUNET_MULTICAST_MemberReplayHandle { }; /** * Request a fragment to be replayed by fragment ID. * * Useful if messages below the @e max_known_fragment_id given when joining are * needed and not known to the client. * * @param member Membership handle. * @param fragment_id ID of a message fragment that this client would like to see replayed. * @param flags Additional flags for the replay request. It is used and defined * by the replay callback. FIXME: which replay callback? FIXME: use enum? * FIXME: why not pass reply cb here? * @return Replay request handle, NULL on error. */ struct GNUNET_MULTICAST_MemberReplayHandle * GNUNET_MULTICAST_member_replay_fragment (struct GNUNET_MULTICAST_Member *member, uint64_t fragment_id, uint64_t flags) { return NULL; } /** * Request a message fragment to be replayed. * * Useful if messages below the @e max_known_fragment_id given when joining are * needed and not known to the client. * * @param member Membership handle. * @param message_id ID of the message this client would like to see replayed. * @param fragment_offset Offset of the fragment within the message to replay. * @param flags Additional flags for the replay request. It is used & defined * by the replay callback. * @param result_cb Function to be called for the replayed message. * @param result_cb_cls Closure for @a result_cb. * @return Replay request handle, NULL on error. */ struct GNUNET_MULTICAST_MemberReplayHandle * GNUNET_MULTICAST_member_replay_message (struct GNUNET_MULTICAST_Member *member, uint64_t message_id, uint64_t fragment_offset, uint64_t flags, GNUNET_MULTICAST_ResultCallback result_cb, void *result_cb_cls) { return NULL; } /** * Cancel a replay request. * * @param rh Request to cancel. */ void GNUNET_MULTICAST_member_replay_cancel (struct GNUNET_MULTICAST_MemberReplayHandle *rh) { } /** * Part a multicast group. * * Disconnects from all group members and invalidates the @a member handle. * * An application-dependent part message can be transmitted beforehand using * #GNUNET_MULTICAST_member_to_origin()) * * @param member Membership handle. */ void GNUNET_MULTICAST_member_part (struct GNUNET_MULTICAST_Member *member) { GNUNET_free (member); } /** * Send a message to the origin of the multicast group. * * @param member Membership handle. * @param message_id Application layer ID for the message. Opaque to multicast. * @param notify Callback to call to get the message. * @param notify_cls Closure for @a notify. * @return Handle to cancel request, NULL on error (i.e. request already pending). */ struct GNUNET_MULTICAST_MemberRequestHandle * GNUNET_MULTICAST_member_to_origin (struct GNUNET_MULTICAST_Member *member, uint64_t message_id, GNUNET_MULTICAST_MemberTransmitNotify notify, void *notify_cls) { return NULL; } /** * Resume message transmission to origin. * * @param rh Request to cancel. */ void GNUNET_MULTICAST_member_to_origin_resume (struct GNUNET_MULTICAST_MemberRequestHandle *rh) { } /** * Cancel request for message transmission to origin. * * @param rh Request to cancel. */ void GNUNET_MULTICAST_member_to_origin_cancel (struct GNUNET_MULTICAST_MemberRequestHandle *rh) { } /* end of multicast_api.c */