tinc/src/protocol.h
Etienne Dechamps 8dd1c8a020 Prepend source node ID information to UDP datagrams.
This commit changes the layout of UDP datagrams to include the 6-byte ID
(i.e. node name hash) of the node that crafted the packet at the very
beginning of the datagram (i.e. before the seqno). Note that this only
applies to SPTPS.

This is implemented at the lowest layer, i.e. in
handle_incoming_vpn_data() and send_sptps_data() functions. Source ID is
added and removed there, in such a way that the upper layers are unaware
of its presence.

This is the first stepping stone towards supporting UDP relaying in
SPTPS, by providing information about the original sender in the packet
itself. Nevertheless, even without relaying this commit already provides
a few benefits such as being able to reliably determine the source node
of a packet in the presence of an unknown source IP address, without
having to painfully go through all node keys. This makes tinc's behavior
much more scalable in this regard.

This change does not break anything with regard to the protocol: It
preserves compatibility with 1.0 and even with older pre-1.1 releases
thanks to a minor protocol version change (17.4). Source ID information
won't be included in packets sent to nodes with minor version < 4.

One drawback, however, is that this change increases SPTPS datagram
overhead by 6 bytes (the size of the source ID itself).
2014-10-04 11:21:44 +01:00

133 lines
4.7 KiB
C

/*
protocol.h -- header for protocol.c
Copyright (C) 1999-2005 Ivo Timmermans,
2000-2013 Guus Sliepen <guus@tinc-vpn.org>
This program 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 of the License, or
(at your option) any later version.
This program 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 this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef __TINC_PROTOCOL_H__
#define __TINC_PROTOCOL_H__
#include "ecdsa.h"
/* Protocol version. Different major versions are incompatible. */
#define PROT_MAJOR 17
#define PROT_MINOR 4 /* Should not exceed 255! */
/* Silly Windows */
#ifdef ERROR
#undef ERROR
#endif
/* Request numbers */
typedef enum request_t {
ALL = -1, /* Guardian for allow_request */
ID = 0, METAKEY, CHALLENGE, CHAL_REPLY, ACK,
STATUS, ERROR, TERMREQ,
PING, PONG,
ADD_SUBNET, DEL_SUBNET,
ADD_EDGE, DEL_EDGE,
KEY_CHANGED, REQ_KEY, ANS_KEY,
PACKET,
/* Tinc 1.1 requests */
CONTROL,
REQ_PUBKEY, ANS_PUBKEY,
REQ_SPTPS,
LAST /* Guardian for the highest request number */
} request_t;
typedef struct past_request_t {
const char *request;
time_t firstseen;
} past_request_t;
extern bool tunnelserver;
extern bool strictsubnets;
extern bool experimental;
extern ecdsa_t *invitation_key;
/* Maximum size of strings in a request.
* scanf terminates %2048s with a NUL character,
* but the NUL character can be written after the 2048th non-NUL character.
*/
#define MAX_STRING_SIZE 2049
#define MAX_STRING "%2048s"
#include "edge.h"
#include "net.h"
#include "node.h"
#include "subnet.h"
/* Basic functions */
extern bool send_request(struct connection_t *, const char *, ...) __attribute__ ((__format__(printf, 2, 3)));
extern void forward_request(struct connection_t *, const char *);
extern bool receive_request(struct connection_t *, const char *);
extern void init_requests(void);
extern void exit_requests(void);
extern bool seen_request(const char *);
/* Requests */
extern bool send_id(struct connection_t *);
extern bool send_metakey(struct connection_t *);
extern bool send_metakey_ec(struct connection_t *);
extern bool send_challenge(struct connection_t *);
extern bool send_chal_reply(struct connection_t *);
extern bool send_ack(struct connection_t *);
extern bool send_status(struct connection_t *, int, const char *);
extern bool send_error(struct connection_t *, int, const char *);
extern bool send_termreq(struct connection_t *);
extern bool send_ping(struct connection_t *);
extern bool send_pong(struct connection_t *);
extern bool send_add_subnet(struct connection_t *, const struct subnet_t *);
extern bool send_del_subnet(struct connection_t *, const struct subnet_t *);
extern bool send_add_edge(struct connection_t *, const struct edge_t *);
extern bool send_del_edge(struct connection_t *, const struct edge_t *);
extern void send_key_changed(void);
extern bool send_req_key(struct node_t *);
extern bool send_ans_key(struct node_t *);
extern bool send_tcppacket(struct connection_t *, const struct vpn_packet_t *);
/* Request handlers */
extern bool id_h(struct connection_t *, const char *);
extern bool metakey_h(struct connection_t *, const char *);
extern bool challenge_h(struct connection_t *, const char *);
extern bool chal_reply_h(struct connection_t *, const char *);
extern bool ack_h(struct connection_t *, const char *);
extern bool status_h(struct connection_t *, const char *);
extern bool error_h(struct connection_t *, const char *);
extern bool termreq_h(struct connection_t *, const char *);
extern bool ping_h(struct connection_t *, const char *);
extern bool pong_h(struct connection_t *, const char *);
extern bool add_subnet_h(struct connection_t *, const char *);
extern bool del_subnet_h(struct connection_t *, const char *);
extern bool add_edge_h(struct connection_t *, const char *);
extern bool del_edge_h(struct connection_t *, const char *);
extern bool key_changed_h(struct connection_t *, const char *);
extern bool req_key_h(struct connection_t *, const char *);
extern bool ans_key_h(struct connection_t *, const char *);
extern bool tcppacket_h(struct connection_t *, const char *);
extern bool control_h(struct connection_t *, const char *);
#endif /* __TINC_PROTOCOL_H__ */