Link quality estimation is useful for link types other than wireless,
especially when using babel with tunnels where packet losses do occur.
Changes since v1:
- fix missing reference to link quality in example configuration
- fix mishandling of default configuration
---
doc/bird.sgml | 7 +++++++
proto/babel/babel.c | 19 ++++++-------------
proto/babel/babel.h | 1 +
proto/babel/config.Y | 8 +++++++-
4 files changed, 21 insertions(+), 14 deletions(-)
diff --git a/doc/bird.sgml b/doc/bird.sgml
index 8041faa9..e597de83 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -1929,6 +1929,7 @@ protocol babel [<name>] {
rx buffer <number>;
tx length <number>;
check link <switch>;
+ link quality <switch>;
next hop ipv4 <address>;
next hop ipv6 <address>;
extended next hop <switch>;
@@ -2032,6 +2033,12 @@ protocol babel [<name>] {
hardware drivers or platforms do not implement this feature. Default:
yes.
+ <tag><label id="babel-link-quality">link quality <m/switch/</tag>
+ If set, link quality estimation is performed on this interface.
+ Link quality is measured by packet loss and is used for computing
+ metrics of routes going through this interface. Default: yes for
+ wireless interfaces, no otherwise.
+
<tag><label id="babel-next-hop-ipv4">next hop ipv4 <m/address/</tag>
Set the next hop address advertised for IPv4 routes advertised on this
interface. Default: the preferred IPv4 address of the interface.
diff --git a/proto/babel/babel.c b/proto/babel/babel.c
index 7f0cca73..6a238d75 100644
--- a/proto/babel/babel.c
+++ b/proto/babel/babel.c
@@ -593,21 +593,15 @@ babel_update_cost(struct babel_neighbor *nbr)
if (!rcv || !nbr->ifa->up)
goto done;
- switch (cf->type)
- {
- case BABEL_IFACE_TYPE_WIRED:
- case BABEL_IFACE_TYPE_TUNNEL:
+ if (!cf->link_quality) {
/* k-out-of-j selection - Appendix 2.1 in the RFC. */
/* Link is bad if less than cf->limit/16 of expected hellos were received
*/
- if (rcv * 16 < cf->limit * max)
- break;
-
- rxcost = cf->rxcost;
- txcost = nbr->txcost;
- break;
-
- case BABEL_IFACE_TYPE_WIRELESS:
+ if (!(rcv * 16 < cf->limit * max)) {
+ rxcost = cf->rxcost;
+ txcost = nbr->txcost;
+ }
+ } else {
/*
* ETX - Appendix 2.2 in the RFC.
*
@@ -622,7 +616,6 @@ babel_update_cost(struct babel_neighbor *nbr)
*/
rxcost = MIN( cf->rxcost * max / rcv, BABEL_INFINITY);
txcost = MIN(nbr->txcost * max / rcv, BABEL_INFINITY);
- break;
}
if (cf->rtt_cost && nbr->srtt > cf->rtt_min)
diff --git a/proto/babel/babel.h b/proto/babel/babel.h
index edde4cab..6145bb58 100644
--- a/proto/babel/babel.h
+++ b/proto/babel/babel.h
@@ -145,6 +145,7 @@ struct babel_iface_config {
u8 type;
u8 limit; /* Minimum number of Hellos to keep
link up */
u8 check_link;
+ u8 link_quality; /* bool + 2 for unspecified */
uint port;
uint hello_interval; /* Hello interval, in us */
uint ihu_interval; /* IHU interval, in us */
diff --git a/proto/babel/config.Y b/proto/babel/config.Y
index b8af0267..4a3d33cb 100644
--- a/proto/babel/config.Y
+++ b/proto/babel/config.Y
@@ -26,7 +26,7 @@ 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)
+ EXTENDED, TUNNEL, RTT, MIN, MAX, DECAY, SEND, TIMESTAMPS, QUALITY)
CF_GRAMMAR
@@ -72,6 +72,7 @@ babel_iface_start:
BABEL_IFACE->rtt_decay = BABEL_RTT_DECAY;
BABEL_IFACE->rtt_send = 1;
BABEL_IFACE->check_link = 1;
+ BABEL_IFACE->link_quality = 2;
BABEL_IFACE->ext_next_hop = 1;
};
@@ -84,6 +85,8 @@ babel_iface_finish:
BABEL_IFACE->hello_interval = BABEL_HELLO_INTERVAL_WIRELESS;
if (!BABEL_IFACE->rxcost)
BABEL_IFACE->rxcost = BABEL_RXCOST_WIRELESS;
+ if (BABEL_IFACE->link_quality == 2)
+ BABEL_IFACE->link_quality = 1;
}
else
{
@@ -93,6 +96,8 @@ babel_iface_finish:
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->link_quality == 2)
+ BABEL_IFACE->link_quality = 0;
}
if (BABEL_IFACE->rtt_cost && !BABEL_IFACE->rtt_send)
@@ -156,6 +161,7 @@ babel_iface_item:
| TX tos { BABEL_IFACE->tx_tos = $2; }
| TX PRIORITY expr { BABEL_IFACE->tx_priority = $3; }
| CHECK LINK bool { BABEL_IFACE->check_link = $3; }
+ | LINK QUALITY bool { BABEL_IFACE->link_quality = $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; }
--
2.41.0
