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Link state support in BGP.
Configurable fast shutdown of a BGP session when an interface loses link.
This commit is contained in:
Ondrej Zajicek
parent
7730553b7e
commit
523f020b5f
@ -316,20 +316,20 @@ protocol rip {
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<sect>Global options
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<p><descrip>
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<tag>include "<m/filename/"</tag>
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<tag>include "<m/filename/"</tag>
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This statement causes inclusion of a new file. <m/Filename/ could also
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be a wildcard. The maximal depth is 8. Note that this statement could be
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used anywhere in the config file, not just as a top-level option.
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<tag><label id="dsc-log">log "<m/filename/"|syslog [name <m/name/]|stderr all|{ <m/list of classes/ }</tag>
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<tag><label id="dsc-log">log "<m/filename/"|syslog [name <m/name/]|stderr all|{ <m/list of classes/ }</tag>
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Set logging of messages having the given class (either <cf/all/ or
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<cf/{ error, trace }/ etc.) into selected destination (a file specified
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as a filename string, syslog with optional name argument, or the stderr
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output). Classes are:
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<cf/info/, <cf/warning/, <cf/error/ and <cf/fatal/ for messages about local problems,
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<cf/debug/ for debugging messages,
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<cf/trace/ when you want to know what happens in the network,
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<cf/remote/ for messages about misbehavior of remote machines,
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<cf/debug/ for debugging messages,
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<cf/trace/ when you want to know what happens in the network,
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<cf/remote/ for messages about misbehavior of remote machines,
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<cf/auth/ about authentication failures,
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<cf/bug/ for internal BIRD bugs.
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You may specify more than one <cf/log/ line to establish logging to
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@ -358,7 +358,7 @@ protocol rip {
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<tag>function <m/name/ (<m/parameters/) <m/local variables/ { <m/commands/ }</tag>
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Define a function. You can learn more about functions in the following chapter.
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<tag>protocol rip|ospf|bgp|... [<m/name/ [from <m/name2/]] { <m>protocol options</m> }</tag>
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Define a protocol instance called <cf><m/name/</cf> (or with a name like
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"rip5" generated automatically if you don't specify any
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@ -508,7 +508,7 @@ agreement").
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This option can be used to override global router id for a given
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protocol. Default: uses global router id.
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<tag>import all | none | filter <m/name/ | filter { <m/filter commands/ } | where <m/filter expression/</tag>
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<tag>import all | none | filter <m/name/ | filter { <m/filter commands/ } | where <m/filter expression/</tag>
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Specify a filter to be used for filtering routes coming from the
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protocol to the routing table. <cf/all/ is shorthand for <cf/where true/
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and <cf/none/ is shorthand for <cf/where false/. Default: <cf/all/.
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@ -586,7 +586,7 @@ agreement").
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An interface option can be used more times with different interface-specific
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options, in that case for given interface the first matching interface
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option is used.
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This option is allowed in BFD, Direct, OSPF, RAdv and RIP protocols, but
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in OSPF protocol it is used in the <cf/area/ subsection.
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@ -599,7 +599,7 @@ agreement").
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<cf>interface "eth1", "eth4", "eth5" { type ptp; };</cf> - start the
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protocol on enumerated interfaces with <cf>type ptp</cf> option.
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<cf>interface -192.168.1.0/24, 192.168.0.0/16;</cf> - start the protocol
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on all interfaces that have address from 192.168.0.0/16, but not from
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192.168.1.0/24.
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@ -632,7 +632,7 @@ agreement").
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used. Specifying passwords does not mean that authentication is enabled,
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authentication can be enabled by separate, protocol-dependent
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<cf/authentication/ option.
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This option is allowed in OSPF and RIP protocols. BGP has also
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<cf/password/ option, but it is slightly different and described
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separately.
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@ -1085,7 +1085,7 @@ foot).
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is true, but <cf>1.0.0.0/16 ˜ [ 1.0.0.0/8- ]</cf> is false.
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Cisco-style patterns like <cf>10.0.0.0/8 ge 16 le 24</cf> can be expressed
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in BIRD as <cf>10.0.0.0/8{16,24}</cf>, <cf>192.168.0.0/16 le 24</cf> as
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in BIRD as <cf>10.0.0.0/8{16,24}</cf>, <cf>192.168.0.0/16 le 24</cf> as
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<cf>192.168.0.0/16{16,24}</cf> and <cf>192.168.0.0/16 ge 24</cf> as
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<cf>192.168.0.0/16{24,32}</cf>.
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@ -1129,7 +1129,7 @@ foot).
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˜ [= 2 3 5 * =]</cf> syntax). The masks resemble wildcard patterns
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as used by UNIX shells. Autonomous system numbers match themselves,
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<cf/*/ matches any (even empty) sequence of arbitrary AS numbers and
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<cf/?/ matches one arbitrary AS number. For example, if <cf>bgp_path</cf>
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<cf/?/ matches one arbitrary AS number. For example, if <cf>bgp_path</cf>
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is 4 3 2 1, then: <tt>bgp_path ˜ [= * 4 3 * =]</tt> is true,
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but <tt>bgp_path ˜ [= * 4 5 * =]</tt> is false. BGP mask
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expressions can also contain integer expressions enclosed in parenthesis
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@ -1206,7 +1206,7 @@ prefix and an ASN as arguments.
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<sect>Control structures
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<p>Filters support two control structures: conditions and case switches.
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<p>Filters support two control structures: conditions and case switches.
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<p>Syntax of a condition is: <cf>if <M>boolean expression</M> then <m/command1/;
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else <m/command2/;</cf> and you can use <cf>{ <m/command_1/; <m/command_2/;
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@ -1232,9 +1232,9 @@ case arg1 {
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else: print "something else";
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}
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if 1234 = i then printn "."; else {
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print "not 1234";
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print "You need {} around multiple commands";
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if 1234 = i then printn "."; else {
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print "not 1234";
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print "You need {} around multiple commands";
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}
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</code>
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@ -1267,7 +1267,7 @@ clist for most purposes.
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<tag><m/ip/ from</tag>
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The router which the route has originated from.
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<tag><m/ip/ gw</tag>
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Next hop packets routed using this route should be forwarded to.
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@ -1448,7 +1448,7 @@ protocol bfd [<name>] {
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BFD sessions are usually created on demand as requested by other
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protocols (like OSPF or BGP). This option allows to explicitly add
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a BFD session to the specified neighbor regardless of such requests.
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The session is identified by the IP address of the neighbor, with
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optional specification of used interface and local IP. By default
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the neighbor must be directly connected, unless the the session is
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@ -1559,13 +1559,13 @@ MD5 password authentication
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(RFC 2385<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc2385.txt">),
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extended communities
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(RFC 4360<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4360.txt">),
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route reflectors
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route reflectors
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(RFC 4456<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4456.txt">),
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graceful restart
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(RFC 4724<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4724.txt">),
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multiprotocol extensions
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(RFC 4760<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4760.txt">),
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4B AS numbers
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4B AS numbers
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(RFC 4893<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc4893.txt">),
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and 4B AS numbers in extended communities
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(RFC 5668<htmlurl url="ftp://ftp.rfc-editor.org/in-notes/rfc5668.txt">).
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@ -1691,6 +1691,13 @@ using the following configuration parameters:
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Specifies a table that is used as an IGP routing table. Default: the
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same as the table BGP is connected to.
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<tag>check link <M>switch</M></tag>
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BGP could use hardware link state into consideration. If enabled,
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BIRD tracks the link state of the associated interface and when link
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disappears (e.g. an ethernet cable is unplugged), the BGP session is
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immediately shut down. Note that this option cannot be used with
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multihop BGP. Default: disabled.
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<tag>bfd <M>switch</M></tag>
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BGP could use BFD protocol as an advisory mechanism for neighbor
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liveness and failure detection. If enabled, BIRD setups a BFD session
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@ -1709,7 +1716,7 @@ using the following configuration parameters:
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(IPv4), 2.6.35+ (IPv6), BSD: since long ago, IPv4 only. Note that full
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(ICMP protection, for example) RFC 5082 support is provided by Linux
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only. Default: disabled.
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<tag>password <m/string/</tag>
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Use this password for MD5 authentication of BGP sessions. Default: no
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authentication. Password has to be set by external utility
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@ -1732,7 +1739,7 @@ using the following configuration parameters:
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id. Clients in a cluster need not know their cluster id and this option
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is not allowed for them. Default: the same as router id.
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<tag>rs client</tag>
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<tag>rs client</tag>
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Be a route server and treat the neighbor as a route server client.
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A route server is used as a replacement for full mesh EBGP routing in
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Internet exchange points in a similar way to route reflectors used in
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@ -1760,7 +1767,7 @@ using the following configuration parameters:
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TX direction. When active, all available routes accepted by the export
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filter are advertised to the neighbor. Default: off.
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<tag>allow local as [<m/number/]</tag>
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<tag>allow local as [<m/number/]</tag>
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BGP prevents routing loops by rejecting received routes with the local
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AS number in the AS path. This option allows to loose or disable the
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check. Optional <cf/number/ argument can be used to specify the maximum
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@ -366,7 +366,7 @@ void
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bgp_conn_enter_established_state(struct bgp_conn *conn)
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{
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struct bgp_proto *p = conn->bgp;
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BGP_TRACE(D_EVENTS, "BGP session established");
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DBG("BGP: UP!!!\n");
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@ -828,7 +828,7 @@ bgp_start_neighbor(struct bgp_proto *p)
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/* Called only for single-hop BGP sessions */
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if (ipa_zero(p->source_addr))
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p->source_addr = p->neigh->ifa->ip;
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p->source_addr = p->neigh->ifa->ip;
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#ifdef IPV6
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{
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@ -855,25 +855,43 @@ static void
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bgp_neigh_notify(neighbor *n)
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{
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struct bgp_proto *p = (struct bgp_proto *) n->proto;
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int ps = p->p.proto_state;
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if (! (n->flags & NEF_STICKY))
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if (n != p->neigh)
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return;
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if (n->scope > 0)
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if ((ps == PS_DOWN) || (ps == PS_STOP))
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return;
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int prepare = (ps == PS_START) && (p->start_state == BSS_PREPARE);
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if (n->scope <= 0)
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{
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if ((p->p.proto_state == PS_START) && (p->start_state == BSS_PREPARE))
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{
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BGP_TRACE(D_EVENTS, "Neighbor found");
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bgp_start_neighbor(p);
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if (!prepare)
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{
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BGP_TRACE(D_EVENTS, "Neighbor lost");
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bgp_store_error(p, NULL, BE_MISC, BEM_NEIGHBOR_LOST);
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/* Perhaps also run bgp_update_startup_delay(p)? */
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bgp_stop(p, 0);
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}
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}
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else if (p->cf->check_link && !(n->iface->flags & IF_LINK_UP))
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{
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if (!prepare)
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{
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BGP_TRACE(D_EVENTS, "Link down");
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bgp_store_error(p, NULL, BE_MISC, BEM_LINK_DOWN);
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if (ps == PS_UP)
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bgp_update_startup_delay(p);
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bgp_stop(p, 0);
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}
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}
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else
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{
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if ((p->p.proto_state == PS_START) || (p->p.proto_state == PS_UP))
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if (prepare)
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{
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BGP_TRACE(D_EVENTS, "Neighbor lost");
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bgp_store_error(p, NULL, BE_MISC, BEM_NEIGHBOR_LOST);
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bgp_stop(p, 0);
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BGP_TRACE(D_EVENTS, "Neighbor ready");
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bgp_start_neighbor(p);
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}
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}
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}
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@ -952,8 +970,8 @@ bgp_start_locked(struct object_lock *lock)
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return;
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}
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p->neigh = neigh_find2(&p->p, &cf->remote_ip, cf->iface, NEF_STICKY);
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if (!p->neigh || (p->neigh->scope == SCOPE_HOST))
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neighbor *n = neigh_find2(&p->p, &cf->remote_ip, cf->iface, NEF_STICKY);
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if (!n)
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{
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log(L_ERR "%s: Invalid remote address %I%J", p->p.name, cf->remote_ip, cf->iface);
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/* As we do not start yet, we can just disable protocol */
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@ -962,11 +980,15 @@ bgp_start_locked(struct object_lock *lock)
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proto_notify_state(&p->p, PS_DOWN);
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return;
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}
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if (p->neigh->scope > 0)
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bgp_start_neighbor(p);
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else
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p->neigh = n;
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if (n->scope <= 0)
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BGP_TRACE(D_EVENTS, "Waiting for %I%J to become my neighbor", cf->remote_ip, cf->iface);
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else if (p->cf->check_link && !(n->iface->flags & IF_LINK_UP))
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BGP_TRACE(D_EVENTS, "Waiting for link on %s", n->iface->name);
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else
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bgp_start_neighbor(p);
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}
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static int
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@ -1173,6 +1195,9 @@ bgp_check_config(struct bgp_config *c)
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ipa_is_link_local(c->source_addr)))
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cf_error("Multihop BGP cannot be used with link-local addresses");
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if (c->multihop && c->check_link)
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cf_error("Multihop BGP cannot depend on link state");
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if (c->multihop && c->bfd && ipa_zero(c->source_addr))
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cf_error("Multihop BGP with BFD requires specified source address");
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@ -1288,7 +1313,7 @@ bgp_store_error(struct bgp_proto *p, struct bgp_conn *c, u8 class, u32 code)
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static char *bgp_state_names[] = { "Idle", "Connect", "Active", "OpenSent", "OpenConfirm", "Established", "Close" };
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static char *bgp_err_classes[] = { "", "Error: ", "Socket: ", "Received: ", "BGP Error: ", "Automatic shutdown: ", ""};
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static char *bgp_misc_errors[] = { "", "Neighbor lost", "Invalid next hop", "Kernel MD5 auth failed", "No listening socket", "BFD session down", "Graceful restart"};
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static char *bgp_misc_errors[] = { "", "Neighbor lost", "Invalid next hop", "Kernel MD5 auth failed", "No listening socket", "Link down", "BFD session down", "Graceful restart"};
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static char *bgp_auto_errors[] = { "", "Route limit exceeded"};
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static const char *
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@ -1396,7 +1421,7 @@ bgp_show_proto_info(struct proto *P)
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tm_remains(c->keepalive_timer), c->keepalive_time);
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}
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if ((p->last_error_class != BE_NONE) &&
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if ((p->last_error_class != BE_NONE) &&
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(p->last_error_class != BE_MAN_DOWN))
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{
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const char *err1 = bgp_err_classes[p->last_error_class];
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@ -62,6 +62,7 @@ struct bgp_config {
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char *password; /* Password used for MD5 authentication */
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struct rtable_config *igp_table; /* Table used for recursive next hop lookups */
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int check_link; /* Use iface link state for liveness detection */
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int bfd; /* Use BFD for liveness detection */
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};
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@ -335,8 +336,9 @@ void bgp_log_error(struct bgp_proto *p, u8 class, char *msg, unsigned code, unsi
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#define BEM_INVALID_NEXT_HOP 2
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#define BEM_INVALID_MD5 3 /* MD5 authentication kernel request failed (possibly not supported) */
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#define BEM_NO_SOCKET 4
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#define BEM_BFD_DOWN 5
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#define BEM_GRACEFUL_RESTART 6
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#define BEM_LINK_DOWN 5
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#define BEM_BFD_DOWN 6
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#define BEM_GRACEFUL_RESTART 7
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/* Automatic shutdown error codes */
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@ -26,7 +26,8 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY,
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PREFER, OLDER, MISSING, LLADDR, DROP, IGNORE, ROUTE, REFRESH,
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INTERPRET, COMMUNITIES, BGP_ORIGINATOR_ID, BGP_CLUSTER_LIST, IGP,
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TABLE, GATEWAY, DIRECT, RECURSIVE, MED, TTL, SECURITY, DETERMINISTIC,
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SECONDARY, ALLOW, BFD, ADD, PATHS, RX, TX, GRACEFUL, RESTART, AWARE)
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SECONDARY, ALLOW, BFD, ADD, PATHS, RX, TX, GRACEFUL, RESTART, AWARE,
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CHECK, LINK)
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CF_GRAMMAR
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@ -97,7 +98,7 @@ bgp_proto:
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| bgp_proto DEFAULT BGP_LOCAL_PREF expr ';' { BGP_CFG->default_local_pref = $4; }
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| bgp_proto SOURCE ADDRESS ipa ';' { BGP_CFG->source_addr = $4; }
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| bgp_proto START DELAY TIME expr ';' { BGP_CFG->start_delay_time = $5; }
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| bgp_proto ERROR FORGET TIME expr ';' { BGP_CFG->error_amnesia_time = $5; }
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| bgp_proto ERROR FORGET TIME expr ';' { BGP_CFG->error_amnesia_time = $5; }
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| bgp_proto ERROR WAIT TIME expr ',' expr ';' { BGP_CFG->error_delay_time_min = $5; BGP_CFG->error_delay_time_max = $7; }
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| bgp_proto DISABLE AFTER ERROR bool ';' { BGP_CFG->disable_after_error = $5; }
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| bgp_proto ENABLE ROUTE REFRESH bool ';' { BGP_CFG->enable_refresh = $5; }
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@ -123,6 +124,7 @@ bgp_proto:
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| bgp_proto GRACEFUL RESTART TIME expr ';' { BGP_CFG->gr_time = $5; }
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| bgp_proto IGP TABLE rtable ';' { BGP_CFG->igp_table = $4; }
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| bgp_proto TTL SECURITY bool ';' { BGP_CFG->ttl_security = $4; }
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| bgp_proto CHECK LINK bool ';' { BGP_CFG->check_link = $4; }
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| bgp_proto BFD bool ';' { BGP_CFG->bfd = $3; cf_check_bfd($3); }
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;
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