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bird/proto/babel/config.Y
Toke Høiland-Jørgensen ed3b730ac3 Babel: Add support for the RTT extension
This adds support to the Babel protocol for the RTT extension specified
in draft-ietf-babel-rtt-extension. While this extension is not yet at the
RFC stage, it is one of the more useful extensions to Babel[0], so it
seems worth having in Bird as well.

The extension adds timestamps to Hello and IHU TLVs and uses these to
compute an RTT to each neighbour. An extra per-neighbour cost is then
computed from the RTT based on a minimum and maximum interval and cost
value specified in the configuration. The primary use case for this is
improving routing in a geographically distributed tunnel-based overlay
network.

The implementation follows the babeld implementation when picking
constants and default configuration values. It also uses the same RTT
smoothing algorithm as babeld, and follows it in adding a new 'tunnel'
interface type which enables RTT by default.

[0] https://alioth-lists.debian.net/pipermail/babel-users/2022-April/003932.html
2024-05-30 12:30:00 +02:00

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/*
* BIRD -- Babel Configuration
*
* Copyright (c) 2015-2016 Toke Hoiland-Jorgensen
* (c) 2016--2017 Ondrej Zajicek <santiago@crfreenet.org>
* (c) 2016--2017 CZ.NIC z.s.p.o.
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
CF_HDR
#include "proto/babel/babel.h"
#include "nest/iface.h"
CF_DEFINES
#define BABEL_CFG ((struct babel_config *) this_proto)
#define BABEL_IFACE ((struct babel_iface_config *) this_ipatt)
CF_DECLS
CF_KEYWORDS(BABEL, INTERFACE, METRIC, RXCOST, HELLO, UPDATE, INTERVAL, PORT,
TYPE, WIRED, WIRELESS, RX, TX, BUFFER, PRIORITY, LENGTH, CHECK, LINK,
NEXT, HOP, IPV4, IPV6, BABEL_METRIC, SHOW, INTERFACES, NEIGHBORS,
ENTRIES, RANDOMIZE, ROUTER, ID, AUTHENTICATION, NONE, MAC, PERMISSIVE,
EXTENDED, TUNNEL, RTT, MIN, MAX, DECAY, SEND, TIMESTAMPS)
CF_GRAMMAR
proto: babel_proto ;
babel_proto_start: proto_start BABEL
{
this_proto = proto_config_new(&proto_babel, $1);
init_list(&BABEL_CFG->iface_list);
BABEL_CFG->hold_time = 1 S_;
};
babel_proto_item:
proto_item
| proto_channel
| INTERFACE babel_iface
| RANDOMIZE ROUTER ID bool { BABEL_CFG->randomize_router_id = $4; }
;
babel_proto_opts:
/* empty */
| babel_proto_opts babel_proto_item ';'
;
babel_proto:
babel_proto_start proto_name '{' babel_proto_opts '}';
babel_iface_start:
{
this_ipatt = cfg_allocz(sizeof(struct babel_iface_config));
add_tail(&BABEL_CFG->iface_list, NODE this_ipatt);
init_list(&this_ipatt->ipn_list);
reset_passwords();
BABEL_IFACE->port = BABEL_PORT;
BABEL_IFACE->type = BABEL_IFACE_TYPE_WIRED;
BABEL_IFACE->limit = BABEL_HELLO_LIMIT;
BABEL_IFACE->tx_tos = IP_PREC_INTERNET_CONTROL;
BABEL_IFACE->tx_priority = sk_priority_control;
BABEL_IFACE->rtt_min = BABEL_RTT_MIN;
BABEL_IFACE->rtt_max = BABEL_RTT_MAX;
BABEL_IFACE->rtt_decay = BABEL_RTT_DECAY;
BABEL_IFACE->rtt_send = 1;
BABEL_IFACE->check_link = 1;
BABEL_IFACE->ext_next_hop = 1;
};
babel_iface_finish:
{
if (BABEL_IFACE->type == BABEL_IFACE_TYPE_WIRELESS)
{
if (!BABEL_IFACE->hello_interval)
BABEL_IFACE->hello_interval = BABEL_HELLO_INTERVAL_WIRELESS;
if (!BABEL_IFACE->rxcost)
BABEL_IFACE->rxcost = BABEL_RXCOST_WIRELESS;
}
else
{
if (!BABEL_IFACE->hello_interval)
BABEL_IFACE->hello_interval = BABEL_HELLO_INTERVAL_WIRED;
if (!BABEL_IFACE->rxcost)
BABEL_IFACE->rxcost = BABEL_RXCOST_WIRED;
if (BABEL_IFACE->type == BABEL_IFACE_TYPE_TUNNEL && !BABEL_IFACE->rtt_cost)
BABEL_IFACE->rtt_cost = BABEL_RXCOST_RTT;
}
if (BABEL_IFACE->rtt_cost && !BABEL_IFACE->rtt_send)
cf_error("Can't set RTT cost when sending timestamps is disabled");
if (BABEL_IFACE->rtt_min >= BABEL_IFACE->rtt_max)
cf_error("Min RTT must be smaller than max RTT");
/* Make sure we do not overflow the 16-bit centisec fields */
if (!BABEL_IFACE->update_interval)
BABEL_IFACE->update_interval = MIN_(BABEL_IFACE->hello_interval*BABEL_UPDATE_INTERVAL_FACTOR, BABEL_MAX_INTERVAL);
BABEL_IFACE->ihu_interval = MIN_(BABEL_IFACE->hello_interval*BABEL_IHU_INTERVAL_FACTOR, BABEL_MAX_INTERVAL);
BABEL_CFG->hold_time = MAX_(BABEL_CFG->hold_time, BABEL_IFACE->update_interval*BABEL_HOLD_TIME_FACTOR);
BABEL_IFACE->passwords = get_passwords();
if (!BABEL_IFACE->auth_type != !BABEL_IFACE->passwords)
cf_error("Authentication and password options should be used together");
if (BABEL_IFACE->passwords)
{
struct password_item *pass;
uint len = 0, i = 0;
WALK_LIST(pass, *BABEL_IFACE->passwords)
{
/* Set default crypto algorithm (HMAC-SHA256) */
if (!pass->alg)
pass->alg = ALG_HMAC_SHA256;
if (!((pass->alg & ALG_HMAC) ||
(pass->alg == ALG_BLAKE2S_128) ||
(pass->alg == ALG_BLAKE2S_256) ||
(pass->alg == ALG_BLAKE2B_256) ||
(pass->alg == ALG_BLAKE2B_512)))
cf_error("Only HMAC and Blake2 algorithms are supported");
len += mac_type_length(pass->alg);
i++;
}
BABEL_IFACE->mac_num_keys = i;
BABEL_IFACE->mac_total_len = len;
}
};
babel_iface_item:
| PORT expr { BABEL_IFACE->port = $2; if (($2<1) || ($2>65535)) cf_error("Invalid port number"); }
| RXCOST expr { BABEL_IFACE->rxcost = $2; if (($2<1) || ($2>65535)) cf_error("Invalid rxcost"); }
| LIMIT expr { BABEL_IFACE->limit = $2; if (($2<1) || ($2>16)) cf_error("Limit must be in range 1-16"); }
| TYPE WIRED { BABEL_IFACE->type = BABEL_IFACE_TYPE_WIRED; }
| TYPE WIRELESS { BABEL_IFACE->type = BABEL_IFACE_TYPE_WIRELESS; }
| TYPE TUNNEL { BABEL_IFACE->type = BABEL_IFACE_TYPE_TUNNEL; }
| HELLO INTERVAL expr_us { BABEL_IFACE->hello_interval = $3; if (($3<BABEL_MIN_INTERVAL) || ($3>BABEL_MAX_INTERVAL)) cf_error("Hello interval must be in range 10 ms - 655 s"); }
| UPDATE INTERVAL expr_us { BABEL_IFACE->update_interval = $3; if (($3<BABEL_MIN_INTERVAL) || ($3>BABEL_MAX_INTERVAL)) cf_error("Update interval must be in range 10 ms - 655 s"); }
| RX BUFFER expr { BABEL_IFACE->rx_buffer = $3; if (($3<256) || ($3>65535)) cf_error("RX buffer must be in range 256-65535"); }
| TX LENGTH expr { BABEL_IFACE->tx_length = $3; if (($3<256) || ($3>65535)) cf_error("TX length must be in range 256-65535"); }
| TX tos { BABEL_IFACE->tx_tos = $2; }
| TX PRIORITY expr { BABEL_IFACE->tx_priority = $3; }
| CHECK LINK bool { BABEL_IFACE->check_link = $3; }
| NEXT HOP IPV4 ipa { BABEL_IFACE->next_hop_ip4 = $4; if (!ipa_is_ip4($4)) cf_error("Must be an IPv4 address"); }
| NEXT HOP IPV6 ipa { BABEL_IFACE->next_hop_ip6 = $4; if (!ipa_is_ip6($4)) cf_error("Must be an IPv6 address"); }
| EXTENDED NEXT HOP bool { BABEL_IFACE->ext_next_hop = $4; }
| AUTHENTICATION NONE { BABEL_IFACE->auth_type = BABEL_AUTH_NONE; }
| AUTHENTICATION MAC { BABEL_IFACE->auth_type = BABEL_AUTH_MAC; BABEL_IFACE->auth_permissive = 0; }
| AUTHENTICATION MAC PERMISSIVE { BABEL_IFACE->auth_type = BABEL_AUTH_MAC; BABEL_IFACE->auth_permissive = 1; }
| RTT MIN expr_us { BABEL_IFACE->rtt_min = $3; }
| RTT MAX expr_us { BABEL_IFACE->rtt_max = $3; }
| RTT COST expr { BABEL_IFACE->rtt_cost = $3; if ($3 >= BABEL_INFINITY) cf_error("RTT cost must be < 65535"); }
| RTT DECAY expr { BABEL_IFACE->rtt_decay = $3; if (($3 < 1) || ($3 > 256)) cf_error("RTT decay must be between 1-256"); }
| SEND TIMESTAMPS bool { BABEL_IFACE->rtt_send = $3; }
| password_list
;
babel_iface_opts:
/* empty */
| babel_iface_opts babel_iface_item ';'
;
babel_iface_opt_list:
/* empty */
| '{' babel_iface_opts '}'
;
babel_iface:
babel_iface_start iface_patt_list_nopx babel_iface_opt_list babel_iface_finish;
dynamic_attr: BABEL_METRIC { $$ = f_new_dynamic_attr(EAF_TYPE_INT, T_INT, EA_BABEL_METRIC); } ;
CF_CLI_HELP(SHOW BABEL, ..., [[Show information about Babel protocol]]);
CF_CLI(SHOW BABEL INTERFACES, optproto opttext, [<name>] [\"<interface>\"], [[Show information about Babel interfaces]])
{ PROTO_WALK_CMD($4, &proto_babel, p) babel_show_interfaces(p, $5); };
CF_CLI(SHOW BABEL NEIGHBORS, optproto opttext, [<name>] [\"<interface>\"], [[Show information about Babel neighbors]])
{ PROTO_WALK_CMD($4, &proto_babel, p) babel_show_neighbors(p, $5); };
CF_CLI(SHOW BABEL ENTRIES, optproto opttext, [<name>], [[Show information about Babel prefix entries]])
{ PROTO_WALK_CMD($4, &proto_babel, p) babel_show_entries(p); };
CF_CLI(SHOW BABEL ROUTES, optproto opttext, [<name>], [[Show information about Babel route entries]])
{ PROTO_WALK_CMD($4, &proto_babel, p) babel_show_routes(p); };
CF_CODE
CF_END