ETX link quality estimation algorithm is useful for link types other than wireless, especially when using babel with tunnels where packet losses do occur. Changes since v2: - change option type from bool to enum - document the properties of the two algorithms Changes since v1: - fix missing reference to link quality in example configuration - fix mishandling of default configuration --- doc/bird.sgml | 10 ++++++++++ proto/babel/babel.c | 8 +++----- proto/babel/babel.h | 8 ++++++++ proto/babel/config.Y | 8 +++++++- 4 files changed, 28 insertions(+), 6 deletions(-) diff --git a/doc/bird.sgml b/doc/bird.sgml index 8041faa9..269a5de9 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 <none|etx>; next hop ipv4 <address>; next hop ipv6 <address>; extended next hop <switch>; @@ -2032,6 +2033,15 @@ protocol babel [<name>] { hardware drivers or platforms do not implement this feature. Default: yes. + <tag><label id="babel-link-quality">link quality none|etx </tag> + This option specifies the link quality estimation algorithm for computing + costs based on Hello history: none or etx. The none (k-out-of-j) algorithm + is suitable for wired links that are either up, in which case they only + occasionally drop a packet, or down, in which case they drop all packets. + The Expected Transmission Cost algorithm, or etx, is suitable for wireless + links that exhibit continuous variation of the link quality. Default: etx for + wireless interfaces, none 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..eb0f50ef 100644 --- a/proto/babel/babel.c +++ b/proto/babel/babel.c @@ -593,10 +593,9 @@ babel_update_cost(struct babel_neighbor *nbr) if (!rcv || !nbr->ifa->up) goto done; - switch (cf->type) + switch (cf->link_quality) { - case BABEL_IFACE_TYPE_WIRED: - case BABEL_IFACE_TYPE_TUNNEL: + case BABEL_IFACE_LINK_QUALITY_NONE: /* 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 */ @@ -606,8 +605,7 @@ babel_update_cost(struct babel_neighbor *nbr) rxcost = cf->rxcost; txcost = nbr->txcost; break; - - case BABEL_IFACE_TYPE_WIRELESS: + case BABEL_IFACE_LINK_QUALITY_ETX: /* * ETX - Appendix 2.2 in the RFC. * diff --git a/proto/babel/babel.h b/proto/babel/babel.h index edde4cab..6a2968f1 100644 --- a/proto/babel/babel.h +++ b/proto/babel/babel.h @@ -118,6 +118,13 @@ enum babel_iface_type { BABEL_IFACE_TYPE_MAX }; +enum babel_iface_link_quality { + BABEL_IFACE_LINK_QUALITY_UNDEF = 0, + BABEL_IFACE_LINK_QUALITY_NONE = 1, + BABEL_IFACE_LINK_QUALITY_ETX = 2, + BABEL_IFACE_LINK_QUALITY_MAX +}; + enum babel_ae_type { BABEL_AE_WILDCARD = 0, BABEL_AE_IP4 = 1, @@ -145,6 +152,7 @@ struct babel_iface_config { u8 type; u8 limit; /* Minimum number of Hellos to keep link up */ u8 check_link; + u8 link_quality; 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..285a3f33 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, ETX) CF_GRAMMAR @@ -84,6 +84,8 @@ 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) + BABEL_IFACE->link_quality = BABEL_IFACE_LINK_QUALITY_ETX; } else { @@ -93,6 +95,8 @@ 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) + BABEL_IFACE->link_quality = BABEL_IFACE_LINK_QUALITY_NONE; } if (BABEL_IFACE->rtt_cost && !BABEL_IFACE->rtt_send) @@ -156,6 +160,8 @@ 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 NONE { BABEL_IFACE->link_quality = BABEL_IFACE_LINK_QUALITY_NONE; } + | LINK QUALITY ETX { BABEL_IFACE->link_quality = BABEL_IFACE_LINK_QUALITY_ETX; } | 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