e3c763eae8
When replying to a PMTU probe, tinc sends a packet with the same length as the PMTU probe itself, which is usually large (~1450 bytes). This is not necessary: the other node wants to know the size of the PMTU probes that have been received, but encoding this information as the actual reply length is probably the most inefficient way to do it. It doubles the bandwidth usage of the PMTU discovery process, and makes it less reliable since large packets are more likely to be dropped. This patch introduces a new PMTU probe reply type, encoded as type "2" in the first byte of the packet, that indicates that the length of the PMTU probe that is being replied to is encoded in the next two bytes of the packet. Thus reply packets are only 3 bytes long. (This also protects against very broken networks that drop very small packets - yes, I've seen it happen on a subnet of a national ISP - in such a case the PMTU probe replies will be dropped, and tinc won't enable UDP communication, which is a good thing.) Because legacy nodes won't understand type 2 probe replies, the minor protocol number is bumped to 3. Note that this also improves bandwidth estimation, as it is able to measure bandwidth in both directions independently (the node receiving the replies is measuring in the TX direction) and the use of smaller reply packets might decrease the influence of jitter.
134 lines
4.7 KiB
C
134 lines
4.7 KiB
C
/*
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protocol.h -- header for protocol.c
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Copyright (C) 1999-2005 Ivo Timmermans,
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2000-2012 Guus Sliepen <guus@tinc-vpn.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef __TINC_PROTOCOL_H__
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#define __TINC_PROTOCOL_H__
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#include "ecdsa.h"
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/* Protocol version. Different major versions are incompatible. */
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#define PROT_MAJOR 17
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#define PROT_MINOR 3 /* Should not exceed 255! */
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/* Silly Windows */
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#ifdef ERROR
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#undef ERROR
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#endif
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/* Request numbers */
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typedef enum request_t {
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ALL = -1, /* Guardian for allow_request */
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ID = 0, METAKEY, CHALLENGE, CHAL_REPLY, ACK,
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STATUS, ERROR, TERMREQ,
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PING, PONG,
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ADD_SUBNET, DEL_SUBNET,
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ADD_EDGE, DEL_EDGE,
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KEY_CHANGED, REQ_KEY, ANS_KEY,
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PACKET,
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/* Tinc 1.1 requests */
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CONTROL,
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REQ_PUBKEY, ANS_PUBKEY,
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REQ_SPTPS,
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LAST /* Guardian for the highest request number */
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} request_t;
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typedef struct past_request_t {
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const char *request;
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time_t firstseen;
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} past_request_t;
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extern bool tunnelserver;
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extern bool strictsubnets;
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extern bool experimental;
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extern ecdsa_t *invitation_key;
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/* Maximum size of strings in a request.
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* scanf terminates %2048s with a NUL character,
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* but the NUL character can be written after the 2048th non-NUL character.
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*/
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#define MAX_STRING_SIZE 2049
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#define MAX_STRING "%2048s"
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#include "edge.h"
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#include "net.h"
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#include "node.h"
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#include "subnet.h"
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/* Basic functions */
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extern bool send_request(struct connection_t *, const char *, ...) __attribute__ ((__format__(printf, 2, 3)));
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extern void forward_request(struct connection_t *, const char *);
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extern bool receive_request(struct connection_t *, const char *);
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extern bool check_id(const char *);
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extern void init_requests(void);
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extern void exit_requests(void);
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extern bool seen_request(const char *);
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/* Requests */
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extern bool send_id(struct connection_t *);
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extern bool send_metakey(struct connection_t *);
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extern bool send_metakey_ec(struct connection_t *);
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extern bool send_challenge(struct connection_t *);
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extern bool send_chal_reply(struct connection_t *);
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extern bool send_ack(struct connection_t *);
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extern bool send_status(struct connection_t *, int, const char *);
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extern bool send_error(struct connection_t *, int, const char *);
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extern bool send_termreq(struct connection_t *);
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extern bool send_ping(struct connection_t *);
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extern bool send_pong(struct connection_t *);
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extern bool send_add_subnet(struct connection_t *, const struct subnet_t *);
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extern bool send_del_subnet(struct connection_t *, const struct subnet_t *);
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extern bool send_add_edge(struct connection_t *, const struct edge_t *);
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extern bool send_del_edge(struct connection_t *, const struct edge_t *);
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extern void send_key_changed(void);
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extern bool send_req_key(struct node_t *);
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extern bool send_ans_key(struct node_t *);
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extern bool send_tcppacket(struct connection_t *, const struct vpn_packet_t *);
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/* Request handlers */
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extern bool id_h(struct connection_t *, const char *);
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extern bool metakey_h(struct connection_t *, const char *);
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extern bool challenge_h(struct connection_t *, const char *);
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extern bool chal_reply_h(struct connection_t *, const char *);
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extern bool ack_h(struct connection_t *, const char *);
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extern bool status_h(struct connection_t *, const char *);
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extern bool error_h(struct connection_t *, const char *);
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extern bool termreq_h(struct connection_t *, const char *);
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extern bool ping_h(struct connection_t *, const char *);
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extern bool pong_h(struct connection_t *, const char *);
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extern bool add_subnet_h(struct connection_t *, const char *);
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extern bool del_subnet_h(struct connection_t *, const char *);
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extern bool add_edge_h(struct connection_t *, const char *);
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extern bool del_edge_h(struct connection_t *, const char *);
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extern bool key_changed_h(struct connection_t *, const char *);
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extern bool req_key_h(struct connection_t *, const char *);
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extern bool ans_key_h(struct connection_t *, const char *);
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extern bool tcppacket_h(struct connection_t *, const char *);
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extern bool control_h(struct connection_t *, const char *);
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#endif /* __TINC_PROTOCOL_H__ */
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