Be more explicit about gateway routes having specific interfaces, to avoid ARP reqs on the wrong interface.

This commit is contained in:
Tony Garnock-Jones 2014-06-19 23:10:50 -04:00
parent 93b1b0fcf3
commit ea9660d83d
3 changed files with 41 additions and 28 deletions

View File

@ -2,14 +2,16 @@
(provide (struct-out ethernet-interface)
(struct-out host-route)
(struct-out gateway-route)
(struct-out net-route))
(struct ethernet-interface (name hwaddr) #:prefab)
;; A Route is one of
;; - (host-route IpAddrBytes NetmaskNat InterfaceName), an own-IP route
;; - (net-route NetAddrBytes NetmaskNat IpAddrBytes), a gateway route for a subnet
;; - (gateway-route NetAddrBytes NetmaskNat IpAddrBytes InterfaceName), a gateway for a subnet
;; - (net-route NetAddrBytes NetmaskNat InterfaceName), an ethernet route for a subnet
;; NetmaskNat in a net-route is a default route.
(struct host-route (ip-addr netmask interface-name) #:prefab)
(struct gateway-route (network-addr netmask gateway-addr interface-name) #:prefab)
(struct net-route (network-addr netmask link) #:prefab)

61
ip.rkt
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@ -64,6 +64,9 @@
(spawn-demand-matcher (host-route (?!) (?!) (?!))
#:supply-level 1
spawn-host-route)
(spawn-demand-matcher (gateway-route (?!) (?!) (?!) (?!))
#:supply-level 1
spawn-gateway-route)
(spawn-demand-matcher (net-route (?!) (?!) (?!))
#:supply-level 1
spawn-net-route)))
@ -71,6 +74,9 @@
(define (host-route-supply ip-addr netmask interface-name)
(sub (host-route ip-addr netmask interface-name) #:level 1))
(define (gateway-route-supply network-addr netmask gateway-addr interface-name)
(sub (gateway-route network-addr netmask gateway-addr interface-name) #:level 1))
(define (net-route-supply network-addr netmask link)
(sub (net-route network-addr netmask link) #:level 1))
@ -123,27 +129,21 @@
(pub (arp-assertion IPv4-ethertype my-address interface-name))
(host-route-supply my-address netmask interface-name)))))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; General net route
(define (spawn-net-route network-addr netmask link)
(cond
[(bytes? link) (spawn-gateway-ip-route network-addr netmask link)]
[(string? link) (spawn-normal-ip-route (net-route-supply network-addr netmask link)
network-addr
netmask
link)]
[else (error 'ip "Invalid net-route: ~v ~v ~v" network-addr netmask link)]))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Gateway IP route
(struct gateway-route-state (routes gateway-interface gateway-hwaddr) #:transparent)
(define (spawn-gateway-ip-route network netmask gateway-addr)
(define (spawn-gateway-route network netmask gateway-addr interface-name)
(define gestalt-for-supply (gateway-route-supply network netmask gateway-addr interface-name))
(define host-route-projector (project-subs (host-route (?!) ? ?)))
(define gateway-route-projector (project-subs (gateway-route (?!) (?!) ? ?)))
(define net-route-projector (project-subs (net-route (?!) (?!) ?)))
(define gateway-arp-projector (project-pubs (arp-query IPv4-ethertype gateway-addr (?!) (?!))))
(define gateway-arp-projector (project-pubs (arp-query IPv4-ethertype
gateway-addr
(?! (ethernet-interface interface-name ?))
(?!))))
(define (covered-by-some-other-route? addr routes)
(for/or ([r (in-set routes)])
@ -155,22 +155,28 @@
(match e
[(routing-update g)
(define host-ips (gestalt-project/single g host-route-projector))
(define net-ips+netmasks (gestalt-project/keys g net-route-projector))
(define gw-nets+netmasks (gestalt-project/keys g gateway-route-projector))
(define net-nets+netmasks (gestalt-project/keys g net-route-projector))
(define gw-ip+hwaddr (let ((vs (gestalt-project/keys g gateway-arp-projector)))
(and vs (not (set-empty? vs)) (set-first vs))))
(when (and gw-ip+hwaddr (not (gateway-route-state-gateway-hwaddr s)))
(log-info "Discovered gateway ~a at ~a on interface ~a."
(ip-address->hostname gateway-addr)
(ethernet-interface-name (car gw-ip+hwaddr))
(pretty-bytes (cadr gw-ip+hwaddr))))
(transition (gateway-route-state
(set-union (for/set ([ip host-ips]) (list ip 32)) net-ips+netmasks)
(set-union (for/set ([ip host-ips]) (list ip 32))
gw-nets+netmasks
net-nets+netmasks)
(and gw-ip+hwaddr (car gw-ip+hwaddr))
(and gw-ip+hwaddr (cadr gw-ip+hwaddr)))
(when (gestalt-empty? (gestalt-filter g (net-route-supply network
netmask
gateway-addr)))
(quit)))]
(when (gestalt-empty? (gestalt-filter g gestalt-for-supply)) (quit)))]
[(message (? ip-packet? p) _ _)
(define gw-if (gateway-route-state-gateway-interface s))
(when (not gw-if)
(log-warning "Gateway hwaddr for ~a not known, packet dropped"
(ip-address->hostname gateway-addr)))
(log-warning "Gateway hwaddr for ~a not known, packet dropped: ~v"
(ip-address->hostname gateway-addr)
p))
(and gw-if
(not (equal? (ip-packet-source-interface p) (ethernet-interface-name gw-if)))
(not (covered-by-some-other-route? (ip-packet-destination p)
@ -184,17 +190,22 @@
(format-ip-packet p)))))]
[_ #f]))
(gateway-route-state (set) #f #f)
(gestalt-union (if (zero? netmask)
(net-route-supply network netmask gateway-addr)
(gestalt-empty))
(gestalt-union gestalt-for-supply
(sub (ip-packet ? ? ? ? ? ?))
(pub (ip-packet ? ? ? ? ? ?))
observe-local-ip-addresses-gestalt
(sub (net-route ? ? ?) #:level 2)
(sub (gateway-route ? ? ? ?) #:level 2)
(projection->gestalt gateway-arp-projector))))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; General net route
(define (spawn-net-route network-addr netmask link)
(spawn-normal-ip-route (net-route-supply network-addr netmask link) network-addr netmask link))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Normal IP route

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@ -23,12 +23,12 @@
(void)
(match (gethostname)
["hop"
(gestalt-union (pub (net-route (bytes 0 0 0 0) 0 (bytes 192 168 1 1)))
(gestalt-union (pub (gateway-route (bytes 0 0 0 0) 0 (bytes 192 168 1 1) "wlan0"))
(pub (host-route (bytes 192 168 1 222) 24 "wlan0")))]
["stockholm.ccs.neu.edu"
(gestalt-union (pub (host-route (bytes 129 10 115 94) 24 "eth0"))
(pub (host-route (bytes 192 168 56 222) 24 "vboxnet0"))
(pub (net-route (bytes 0 0 0 0) 0 (bytes 129 10 115 1))))]
(pub (gateway-route (bytes 0 0 0 0) 0 (bytes 129 10 115 1) "eth0")))]
[else
(error 'stack-configuration "No setup for hostname ~a" (gethostname))]))