* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT [not found] <20030713005345.1fea1092.davem@redhat.com> @ 2003-07-14 23:29 ` kuznet 2003-07-15 6:28 ` Pekka Savola 0 siblings, 1 reply; 16+ messages in thread From: kuznet @ 2003-07-14 23:29 UTC (permalink / raw) To: David S. Miller; +Cc: jmorris, netdev Hello! > Hey guys, even though yoshfuji is away I don't see any > reason why I shouldn't apply the patch below to both > 2.4.x and 2.5.x. It looks very uncontroversial to me. > > Any objections? I would wait for experts. Technically IPv6 does not allow use of non-link-local address as nexthop address, because nexthop address is expected to be unique for router. Use of IPv4-COMPAT format for tunnels was a hack to make use of tunnel more handly, it just a tricky way to encapsulate an IPv4 address inside IPv6 one, it has nothing to do with _real_ IPv4-COMPAT addresses, (though logically IPv4-COMPAT addresses _are_ really link-local for 6over4 "network") it is just an element of our API. Use of 6of4 address is very strange idea in this context, it does not contradict to anything, of course, but it looks utterly stupid: 6to4 is a complicated format, where information about nexthop is encoded in an inapproriate way. The questions sort of: "What the hell? I do a route with nexthop 2002:x:y::a:b and a:b disappears somewhere." And the question is right, because plain logic requires to use a:b as meaningful part of nexthop, it is the part which provides node _identity_, x:y is just routing information, identifying particullar "6to4" network, it is meaningless when used as a nexthop address. Shortly, this is mess. Technically, it is just one more trick and useless one, logically... mess. Alexey ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-14 23:29 ` Fw: [PATCH] IPv6: Allow 6to4 routes with SIT kuznet @ 2003-07-15 6:28 ` Pekka Savola 2003-07-15 14:28 ` kuznet 0 siblings, 1 reply; 16+ messages in thread From: Pekka Savola @ 2003-07-15 6:28 UTC (permalink / raw) To: kuznet; +Cc: David S. Miller, jmorris, netdev On Tue, 15 Jul 2003 kuznet@ms2.inr.ac.ru wrote: > > Hey guys, even though yoshfuji is away I don't see any > > reason why I shouldn't apply the patch below to both > > 2.4.x and 2.5.x. It looks very uncontroversial to me. > > > > Any objections? > > I would wait for experts. > > Technically IPv6 does not allow use of non-link-local address > as nexthop address, because nexthop address is expected to be unique > for router. I think we have two choices here: 1) modify /sbin/ip and /sbin/route (and the rest if any) so that they'll parse global next-hop information and resolve it for the kernel, and report the resolved information to the kernel (see the other thread) 2) the kernel supports "must-resolve" next-hops. > Use of IPv4-COMPAT format for tunnels was a hack to make use of tunnel more > handly, it just a tricky way to encapsulate an IPv4 address inside > IPv6 one, it has nothing to do with _real_ IPv4-COMPAT addresses, > (though logically IPv4-COMPAT addresses _are_ really link-local > for 6over4 "network") it is just an element of our API. Use of 6of4 address > is very strange idea in this context, it does not contradict to anything, > of course, but it looks utterly stupid: 6to4 is a complicated format, where > information about nexthop is encoded in an inapproriate way. > The questions sort of: "What the hell? I do a route with nexthop > 2002:x:y::a:b and a:b disappears somewhere." And the question is right, > because plain logic requires to use a:b as meaningful part of nexthop, > it is the part which provides node _identity_, x:y is just routing information, > identifying particullar "6to4" network, it is meaningless when used > as a nexthop address. Apart from architectural purity (I agree it's messy), I think the practical situation is rather simple: for the case of a:b in 6to4, they're always irrelevant. They always refer to the same next-hop whatever information you'll put in there, the implementations won't care (because as a next-hop, it's just a way of saying "the router at address 2002:V4ADDR". Note that nothing _prevents_ you from treating a:b in 2002:x:y::a:b as a meaningful part of the nexthop. They'll just always refer to the same node for whatever a:b you use. Note that the prefix length of 2002:x:y::a:b is /16 -- you should really rewrite your next-hop considerations with s/a:b/x:y::a:b/. I think the problem for of implementation is that "6to4" technique has just been hacked in (but quite nicely). It's a bit, but not much, more special than that IMO. -- Pekka Savola "You each name yourselves king, yet the Netcore Oy kingdom bleeds." Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-15 6:28 ` Pekka Savola @ 2003-07-15 14:28 ` kuznet 2003-07-15 19:26 ` Pekka Savola 2003-07-16 22:28 ` Mika Liljeberg 0 siblings, 2 replies; 16+ messages in thread From: kuznet @ 2003-07-15 14:28 UTC (permalink / raw) To: Pekka Savola; +Cc: davem, jmorris, netdev Hello! > 1) modify /sbin/ip and /sbin/route (and the rest if any) so that they'll > parse global next-hop information and resolve it for the kernel, and > report the resolved information to the kernel (see the other thread) No, really. It is problem of user to supply reasonable values. This policy is not forced, because there are many cases when it does not make sense (f.e. on all the routers, on all the PtP interfaces et al). Verification of validity of nexthop is to be done only when receiving nexthop through addrconf or redirect et al. I guess interiour protocols also should take care of it. > 2) the kernel supports "must-resolve" next-hops. I do not know what it is. > practical situation is rather simple: for the case of a:b in 6to4, they're > always irrelevant. Sure. It is becasue use of 6to4 address is meaningless in this context. It is thought which I try to deliver. > Note that nothing _prevents_ you from treating a:b in 2002:x:y::a:b I do not understand the rest. Listen, tunnel needs an _IPv4_ address for destiantion of tunnel. Because our routing does not permit to use different address family as nexthop, we did trick presenting it as an IPv4-compat address. We could do this differently, f.e. to use FFFF:EEEE:IPv4-addr:CCCC:DDDD with the same success or any other randomly chosen encapsulation. And this silly combination is still _better_ than 6to4 address, which contains redundant information, which can be mixed up with real _IPv6_ 6to4 addresses and whihc contains IPv4 address in some place which used to be identification of a network prefix. Alexey ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-15 14:28 ` kuznet @ 2003-07-15 19:26 ` Pekka Savola 2003-07-15 23:32 ` kuznet 2003-07-16 22:28 ` Mika Liljeberg 1 sibling, 1 reply; 16+ messages in thread From: Pekka Savola @ 2003-07-15 19:26 UTC (permalink / raw) To: kuznet; +Cc: davem, jmorris, netdev On Tue, 15 Jul 2003 kuznet@ms2.inr.ac.ru wrote: > > 1) modify /sbin/ip and /sbin/route (and the rest if any) so that they'll > > parse global next-hop information and resolve it for the kernel, and > > report the resolved information to the kernel (see the other thread) > > No, really. It is problem of user to supply reasonable values. Such addresses are link-locals, of link local scope only. A link-local IPv6 address is awfully difficult to remember and type for all of your possible links. The only reasonable value user could supply is a global address. If the user doesn't have to supply anything .. that's another thing. > Listen, tunnel needs an _IPv4_ address for destiantion of tunnel. > Because our routing does not permit to use different address family > as nexthop, we did trick presenting it as an IPv4-compat address. > We could do this differently, f.e. to use FFFF:EEEE:IPv4-addr:CCCC:DDDD > with the same success or any other randomly chosen encapsulation. > > And this silly combination is still _better_ than 6to4 address, which > contains redundant information, which can be mixed up with real _IPv6_ > 6to4 addresses and whihc contains IPv4 address in some place which > used to be identification of a network prefix. Note that what is redundant information in certain scenarios for the *kernel* may not be redundant information for the *user*. Please describe what you mean by "real IPv6 6to4 addresses". If the node processing those as a next-hop supports 6to4 and has the sit0 pseudointerface configured, the address will be but through the special handling. If the node doesn't support 6to4 or doesn't have the sit0 pseudointerface configured, the address will be processed as normal, as any other IPv6 nexthop. Right? I fail to see what's the fuss about redundant information. Redundant information can be ignored. This is not computer science theory, removing everything which is not directly relevant. The use of the same representation for the next-hop (2002:F00:BA::x) as an address (2002:BA:F00:y) is the only logical, user-friendly way. -- Pekka Savola "You each name yourselves king, yet the Netcore Oy kingdom bleeds." Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-15 19:26 ` Pekka Savola @ 2003-07-15 23:32 ` kuznet 2003-07-16 6:12 ` Pekka Savola 0 siblings, 1 reply; 16+ messages in thread From: kuznet @ 2003-07-15 23:32 UTC (permalink / raw) To: Pekka Savola; +Cc: davem, jmorris, netdev Hello! > Such addresses are link-locals, of link local scope only. A link-local > IPv6 address is awfully difficult to remember and type for all of your > possible links. > > The only reasonable value user could supply is a global address. So what? I do not see connection to previous. You want to live with global addresses as nexthop? OK. But I remember you have spoken something quite opposite yesterday. > Please describe what you mean by "real IPv6 6to4 addresses". ... > If the node processing those as a next-hop supports 6to4 and has the sit0 > pseudointerface configured, the address will be but through the special > handling. > > If the node doesn't support 6to4 or doesn't have the sit0 pseudointerface > configured, the address will be processed as normal, as any other IPv6 > nexthop. > > Right? I do not understand why did you ask previous question. You answered to this. > Redundant information can be ignored. This is not computer science > theory, removing everything which is not directly relevant. The use of > the same representation for the next-hop (2002:F00:BA::x) as an address > (2002:BA:F00:y) is the only logical, user-friendly way. What a bullshit... The second is address of host "x". The first is supposed to be address of host F00:BA, whatever it is. Probably, you can decrypt this only because poisoned by computer science. :-) Just to complete discussion, let's stay on format fe80::A.B.C.D, for example. Unlike anothers it is 100% logically clean. :-) Alexey ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-15 23:32 ` kuznet @ 2003-07-16 6:12 ` Pekka Savola 2003-07-17 0:20 ` kuznet 0 siblings, 1 reply; 16+ messages in thread From: Pekka Savola @ 2003-07-16 6:12 UTC (permalink / raw) To: kuznet; +Cc: davem, jmorris, netdev On Wed, 16 Jul 2003 kuznet@ms2.inr.ac.ru wrote: > > Such addresses are link-locals, of link local scope only. A link-local > > IPv6 address is awfully difficult to remember and type for all of your > > possible links. > > > > The only reasonable value user could supply is a global address. > > So what? I do not see connection to previous. You want to live with global > addresses as nexthop? Yes, I dare to say that they're a requirement. (But to be clear, when I talk about "global nexthop", I'm only interested in nexthops which are on-link. That is, if you have prefix 3FFF:FFFF:A:B::/64, setting 3FFE:FFFF:A:B::1 would be ok, but 3FFE:FFFF:F00:BA::1 would not *have* to work.) > OK. But I remember you have spoken something quite > opposite yesterday. I don't recall that. I think I was only suggesting that ONE possible way of implementing it (which I wouldn't think is the best one) is make that the user space tools' problem: i.e. make them resolve a globally addressed nexthop to a link-local nexthop. > > Redundant information can be ignored. This is not computer science > > theory, removing everything which is not directly relevant. The use of > > the same representation for the next-hop (2002:F00:BA::x) as an address > > (2002:BA:F00:y) is the only logical, user-friendly way. > > What a bullshit... The second is address of host "x". The first is supposed > to be address of host F00:BA, whatever it is. Probably, you can decrypt > this only because poisoned by computer science. :-) You read too much to in what I wrote (or maybe I wrote too much :-) -- what I mean is that 6to4 addresses have a very specific format. It's completely illogical and unfriendly to the users to require use different formats when they use 6to4 addresses as nexthops and "normal" addresses. > Just to complete discussion, let's stay on format fe80::A.B.C.D, for example. > Unlike anothers it is 100% logically clean. :-) I can't disagree with you there; it's simple, but it's NOT what specifications use and the *users* want and need to use. -- Pekka Savola "You each name yourselves king, yet the Netcore Oy kingdom bleeds." Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-16 6:12 ` Pekka Savola @ 2003-07-17 0:20 ` kuznet 2003-07-17 7:04 ` Pekka Savola 0 siblings, 1 reply; 16+ messages in thread From: kuznet @ 2003-07-17 0:20 UTC (permalink / raw) To: Pekka Savola; +Cc: davem, jmorris, netdev Hello! > Yes, I dare to say that they're a requirement. Nope. IPv6 host routing is based on assumption of link-locality of the next hop. Probably, you want to read some rfcs or to look into code. > the user space tools' problem: i.e. make them resolve a globally addressed > nexthop to a link-local nexthop. Impossible, as I said. [ NOTE, the subject changed back to correct one at this point. Seems, one sentence, written by me has grown to some huge tumor eating original one completely. :-) ] > specifications use and the *users* want and need to use. Sigh, there no specifications about tricks used by Linux routing tables, *users* are unlikely to want to use this feature at all, as Mika noticed. And when they want, they want to right: ip route add 3ffe::.... via 193.233.7.65 rather than crap sort of ip route add 3ffe::.... via 2002:<something in latin> I do not understand, what the hell is going on with you. I am already sorry that started this. :-) Alexey ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-17 0:20 ` kuznet @ 2003-07-17 7:04 ` Pekka Savola 2003-07-17 11:16 ` Mika Liljeberg 0 siblings, 1 reply; 16+ messages in thread From: Pekka Savola @ 2003-07-17 7:04 UTC (permalink / raw) To: kuznet; +Cc: davem, jmorris, netdev On Thu, 17 Jul 2003 kuznet@ms2.inr.ac.ru wrote: > > Yes, I dare to say that they're a requirement. > > Nope. IPv6 host routing is based on assumption of link-locality of the > next hop. Probably, you want to read some rfcs or to look into code. This is not correct. Perhaps the RFC's have changed in the meantime, but at least RFC2461 does *not* make such an assumption (AFAICS). In the document, there is a basic assumption that the next-hop is *on-link*. In the document, there are assumptions on verifying whether the redirects come from the router you're currently using: this is simpler when you use only link-locals as next-hops, but it is certainly *NOT* a requirement. (The spec in question will be revised in the short term, so I'll take this issue up for clarification..) > > specifications use and the *users* want and need to use. > > Sigh, there no specifications about tricks used by Linux routing tables, > *users* are unlikely to want to use this feature at all, as Mika noticed. > And when they want, they want to right: > > ip route add 3ffe::.... via 193.233.7.65 That would be simpler but, we actually require: ip route add 3ffe::... via ::193.233.7.65 and thus require a route for ::/96. That's confusing: ::/96 has a very specific purpose in RFCs, and we should not be overloading the functionality, it's just plain confusing. > rather than crap sort of > > ip route add 3ffe::.... via 2002:<something in latin> I'm not saying we need to prevent the users from using the former. I'm just saying that we must not prevent the users from using the latter; please check e.g. the RFC3068 section 2.5. If we don't support something like that, it'll just confuse the users more. -- Pekka Savola "You each name yourselves king, yet the Netcore Oy kingdom bleeds." Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-17 7:04 ` Pekka Savola @ 2003-07-17 11:16 ` Mika Liljeberg 2003-07-17 11:54 ` Mika Liljeberg 0 siblings, 1 reply; 16+ messages in thread From: Mika Liljeberg @ 2003-07-17 11:16 UTC (permalink / raw) To: Pekka Savola; +Cc: kuznet, davem, jmorris, netdev On Thu, 2003-07-17 at 10:04, Pekka Savola wrote: > > ip route add 3ffe::.... via 193.233.7.65 > > That would be simpler but, we actually require: > > ip route add 3ffe::... via ::193.233.7.65 > > and thus require a route for ::/96. That's confusing: ::/96 has a very > specific purpose in RFCs, and we should not be overloading the > functionality, it's just plain confusing. I agree with Pekka. Alexey, you yourself admitted that this hack was put in, because you needed a way to represent an IPv4 address in IPv6 format. The IPv4-mapped format (::ffff:a.b.c.d) exists exactly for this purpose. User space tools can accept it as a.b.c.d and convert to IPv4-Mapped for the IPv6 API. There is no need to invent non-standard practises. It may be convenient to think that the IPv4 Internet is a virtual link connecting all 6to4 routers and IPv4 compatible addresses could be seen as the link-local addresses, but this is just an affectation that is not backed by any IETF specification. Overloading the IPv4-compatible address in this way is just confusing, because it creates the impression that the stack will actually take steps to resolve the gateway address to a next hop address that is on-link. (I'm not saying it should, but you can see where the confusion arises). MikaL ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-17 11:16 ` Mika Liljeberg @ 2003-07-17 11:54 ` Mika Liljeberg 2003-07-17 13:55 ` Pekka Savola 0 siblings, 1 reply; 16+ messages in thread From: Mika Liljeberg @ 2003-07-17 11:54 UTC (permalink / raw) To: Pekka Savola; +Cc: kuznet, davem, jmorris, netdev On Thu, 2003-07-17 at 14:16, Mika Liljeberg wrote: > On Thu, 2003-07-17 at 10:04, Pekka Savola wrote: > > > ip route add 3ffe::.... via 193.233.7.65 > > > > That would be simpler but, we actually require: > > > > ip route add 3ffe::... via ::193.233.7.65 > > > > and thus require a route for ::/96. That's confusing: ::/96 has a very > > specific purpose in RFCs, and we should not be overloading the > > functionality, it's just plain confusing. > > I agree with Pekka. Alexey, you yourself admitted that this hack was put > in, because you needed a way to represent an IPv4 address in IPv6 > format. The IPv4-mapped format (::ffff:a.b.c.d) exists exactly for this > purpose. User space tools can accept it as a.b.c.d and convert to > IPv4-Mapped for the IPv6 API. There is no need to invent non-standard > practises. Ok, I have to correct myself a bit here. Looking at the 6to4 RFC it actually does recommend the fe80::v4addr format, already mentioned, in case a link-local address is needed. So we would have: ip route add 3ffe:... via fe80::bada:bee4 dev sitX Clean, although not as convenient for the user. MikaL ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-17 11:54 ` Mika Liljeberg @ 2003-07-17 13:55 ` Pekka Savola 2003-07-17 14:35 ` Mika Liljeberg 0 siblings, 1 reply; 16+ messages in thread From: Pekka Savola @ 2003-07-17 13:55 UTC (permalink / raw) To: Mika Liljeberg; +Cc: kuznet, davem, jmorris, netdev On 17 Jul 2003, Mika Liljeberg wrote: > On Thu, 2003-07-17 at 14:16, Mika Liljeberg wrote: > > On Thu, 2003-07-17 at 10:04, Pekka Savola wrote: > > > > ip route add 3ffe::.... via 193.233.7.65 > > > > > > That would be simpler but, we actually require: > > > > > > ip route add 3ffe::... via ::193.233.7.65 > > > > > > and thus require a route for ::/96. That's confusing: ::/96 has a very > > > specific purpose in RFCs, and we should not be overloading the > > > functionality, it's just plain confusing. > > > > I agree with Pekka. Alexey, you yourself admitted that this hack was put > > in, because you needed a way to represent an IPv4 address in IPv6 > > format. The IPv4-mapped format (::ffff:a.b.c.d) exists exactly for this > > purpose. User space tools can accept it as a.b.c.d and convert to > > IPv4-Mapped for the IPv6 API. There is no need to invent non-standard > > practises. > > Ok, I have to correct myself a bit here. Looking at the 6to4 RFC it > actually does recommend the fe80::v4addr format, already mentioned, in > case a link-local address is needed. Note that the spec refers to the generation of your *own* fe80::x address, in the case that e.g. the implementations like to have link-local addresses on interfaces. One doesn't say that when you're contacting 6to4 relays, you should use a link-local address formed like above to communicagte the IP address. > So we would have: > > ip route add 3ffe:... via fe80::bada:bee4 dev sitX > > Clean, although not as convenient for the user. I disagree a bit on cleanliness. The problem with the above is that when you see the next-hop "fe80::bada:bee4", you can't have any idea whether it really means "tunnel to (dec)bada:bee4" or "a router known as fe80::bada:bee4". It depends on the interface. The context of 6to4 is lost. For that reason, IMO 2002:v4:addr is the clearest, and "via v4addr" seems like the next best one (IMHO). -- Pekka Savola "You each name yourselves king, yet the Netcore Oy kingdom bleeds." Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-17 13:55 ` Pekka Savola @ 2003-07-17 14:35 ` Mika Liljeberg 0 siblings, 0 replies; 16+ messages in thread From: Mika Liljeberg @ 2003-07-17 14:35 UTC (permalink / raw) To: Pekka Savola; +Cc: kuznet, davem, jmorris, netdev Pekka, Looks like I've talked myself around to Alexey's point of view. :-) On Thu, 2003-07-17 at 16:55, Pekka Savola wrote: > Note that the spec refers to the generation of your *own* fe80::x address, > in the case that e.g. the implementations like to have link-local > addresses on interfaces. One doesn't say that when you're contacting 6to4 > relays, you should use a link-local address formed like above to > communicagte the IP address. Yes, but section 3.7 of rfc2893 talks about the use of that link-layer address with routing protocols. I take this to include "as next hop address". > I disagree a bit on cleanliness. The problem with the above is that when > you see the next-hop "fe80::bada:bee4", you can't have any idea whether it > really means "tunnel to (dec)bada:bee4" or "a router known as > fe80::bada:bee4". It depends on the interface. The context of 6to4 is > lost. I would say that is a feature. The next hop address *always* identifies the next hop router, and it's a link-local unicast as it is supposed to be. In the case of 6to4, the next hop router just happens to be a 6to4 relay located on the virtual link provided by the SIT interface. The tunneling is purely a property of the SIT interface, the routing code doesn't have to care. Theoretically, you could even create solicited node multicast addresses the same way and run ND over the tunnel (not that it's needed). MikaL ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-15 14:28 ` kuznet 2003-07-15 19:26 ` Pekka Savola @ 2003-07-16 22:28 ` Mika Liljeberg 2003-07-16 23:28 ` kuznet 1 sibling, 1 reply; 16+ messages in thread From: Mika Liljeberg @ 2003-07-16 22:28 UTC (permalink / raw) To: kuznet; +Cc: Pekka Savola, davem, jmorris, netdev Alexey, > And this silly combination is still _better_ than 6to4 address, which > contains redundant information, which can be mixed up with real _IPv6_ > 6to4 addresses and whihc contains IPv4 address in some place which > used to be identification of a network prefix. While I see where you're coming from, I don't really understand what the fuss is all about. IMHO, the real hack is being able to specify the tunnel endpoint using a gateway route in the first place. Whether that gateway address is IPv4-compatible or a 6to4 address is just a minor detail. I view my patch as a simple convenience to the user, extending a hack that already exists. A more "correct" way would be to specify the gateway address in the remote address field of the point-to-point SIT interface, and live with the fact that you need a separate SIT interface for each 6to4 gateway that you want to tunnel to. This already works, so the IPv4-compat route hack is actually redundant. My understanding was that it is there simply for convenience. MikaL ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-16 22:28 ` Mika Liljeberg @ 2003-07-16 23:28 ` kuznet 2003-07-16 23:39 ` Mika Liljeberg 0 siblings, 1 reply; 16+ messages in thread From: kuznet @ 2003-07-16 23:28 UTC (permalink / raw) To: Mika Liljeberg; +Cc: pekkas, davem, jmorris, netdev Hello! > While I see where you're coming from, I don't really understand what the > fuss is all about. The issue definitely does not worth of time already spent for the discussion. All the fuss is about the fact that this code lived and will live for years. If we allowed to add small tricks of this kind, it would end up as a full mess. Each convenience trick must have a logical background. I have been asked for an opinion, this is my opinion: 6to4 is wrong, addresses in format of 6over4 are natural, if they are deprecated, another and even more natural variant is use of link-local format, fe80::a.b.c.d. Alexey ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-16 23:28 ` kuznet @ 2003-07-16 23:39 ` Mika Liljeberg 2003-07-16 23:58 ` kuznet 0 siblings, 1 reply; 16+ messages in thread From: Mika Liljeberg @ 2003-07-16 23:39 UTC (permalink / raw) To: kuznet; +Cc: pekkas, davem, jmorris, netdev On Thu, 2003-07-17 at 02:28, kuznet@ms2.inr.ac.ru wrote: > > While I see where you're coming from, I don't really understand what the > > fuss is all about. > > The issue definitely does not worth of time already spent for the discussion. I agree. :) > All the fuss is about the fact that this code lived and will live for years. > If we allowed to add small tricks of this kind, it would end up as a full mess. > Each convenience trick must have a logical background. So what's the background for having the hack to specify a tunnel EP with a gateway route? > I have been asked for an opinion, this is my opinion: 6to4 is wrong, > addresses in format of 6over4 are natural, if they are deprecated, > another and even more natural variant is use of link-local format, > fe80::a.b.c.d. IPv4-mapped would be semantically correct. It definately can't be confused with any real IPv6 address. MikaL ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: Fw: [PATCH] IPv6: Allow 6to4 routes with SIT 2003-07-16 23:39 ` Mika Liljeberg @ 2003-07-16 23:58 ` kuznet 0 siblings, 0 replies; 16+ messages in thread From: kuznet @ 2003-07-16 23:58 UTC (permalink / raw) To: Mika Liljeberg; +Cc: pekkas, davem, jmorris, netdev Hello! > So what's the background for having the hack to specify a tunnel EP with > a gateway route? Technically, it allows to avoid creating hundreds of devices to maintain lots of tunnels. Actually, it exists due to historical reasons. ipip and ipip6 tunnels used the trick from the very beginning. But f.e. ipgre device was new, so it uses more correct approach: actual mapping cross address families can be made via neighbour tables. But this requires to know an IPv6 address of the nexthop. Clean, but inconvenient. :-) Alexey ^ permalink raw reply [flat|nested] 16+ messages in thread
end of thread, other threads:[~2003-07-17 14:35 UTC | newest] Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <20030713005345.1fea1092.davem@redhat.com> 2003-07-14 23:29 ` Fw: [PATCH] IPv6: Allow 6to4 routes with SIT kuznet 2003-07-15 6:28 ` Pekka Savola 2003-07-15 14:28 ` kuznet 2003-07-15 19:26 ` Pekka Savola 2003-07-15 23:32 ` kuznet 2003-07-16 6:12 ` Pekka Savola 2003-07-17 0:20 ` kuznet 2003-07-17 7:04 ` Pekka Savola 2003-07-17 11:16 ` Mika Liljeberg 2003-07-17 11:54 ` Mika Liljeberg 2003-07-17 13:55 ` Pekka Savola 2003-07-17 14:35 ` Mika Liljeberg 2003-07-16 22:28 ` Mika Liljeberg 2003-07-16 23:28 ` kuznet 2003-07-16 23:39 ` Mika Liljeberg 2003-07-16 23:58 ` kuznet
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