Hi.
Let's try that again, with inline patches and pointers to them since they seemed to be stripped from the last mail: http://www.habets.pp.se/synscan/files/ldpctl-impnull.patch http://www.habets.pp.se/synscan/files/ldpd-impnull.patch I played around a bit with ospfd and ldpd against real cisco routers, and noticed some strange things. ldpctl ------ First of all I saw that the output from "ldpctl show lib" and lfib showed label "3" instead of the well-known "implicit null". I've patched ldpctl to show what I think is more appropriate output. ldpctl-impnull.patch. Apologies if this isn't the output you had in mind. ldpd ---- Then I saw that any packet *using* the implicit null label actually went out over the wire with a label of 3. That's not very implicit. In fact, that's explicit. I added a check to ldpd if it's about to tell the kernel to place an imp-null label (swap or push, for MPLS and IP) and if so change it to skipping that label (using pop or return instead). Also, I'm not quite sure what "In use" is supposed to mean, since if I take this line for example: 123.0.0.1/32 123.0.0.1 23 - no It's obviously in use and being announced over LDP to the other routers. c3640-2#show mpls ldp bindings 123.0.0.1 32 tib entry: 123.0.0.1/32, rev 30 remote binding: tsr: 1.0.0.100:0, tag: 23 So I changed the "in use" bit to be "yes" even if there's no outgoing label. As long as there's an incoming label the entry is, in my eyes, in use. One more issue that my patches don't address is that the local label of loopbacks aren't imp-null. I take it this is because loopbacks don't get the C flag in the routing table. Oh, and one last thing: that 123.0.0.1/32 above is actually a loopback 123.0.0.1/24. And while they can both be found in the routing table, lib and lfib, the /32 is not announced by ospfd and should therefore not be in LDP either. --------- typedef struct me_s { char name[] = { "Thomas Habets" }; char email[] = { "[hidden email]" }; char kernel[] = { "Linux" }; char *pgpKey[] = { "http://www.habets.pp.se/pubkey.txt" }; char pgp[] = { "A8A3 D1DD 4AE0 8467 7FDE 0945 286A E90A AD48 E854" }; char coolcmd[] = { "echo '. ./_&. ./_'>_;. ./_" }; } me_t; Index: kroute.c =================================================================== RCS file: /cvs/src/usr.sbin/ldpd/kroute.c,v retrieving revision 1.7 diff -u -r1.7 kroute.c --- kroute.c 3 Mar 2010 10:17:05 -0000 1.7 +++ kroute.c 10 Apr 2010 15:55:56 -0000 @@ -1091,10 +1091,17 @@ iov[iovcnt].iov_base = &label_out; iov[iovcnt++].iov_len = sizeof(label_out); - if (family == AF_MPLS) - hdr.rtm_mpls = MPLS_OP_SWAP; - else - hdr.rtm_mpls = MPLS_OP_PUSH; + if (ntohl(kroute->remote_label) >> MPLS_LABEL_OFFSET == MPLS_LABEL_IMPLNULL) { + if (family == AF_MPLS) + hdr.rtm_mpls = MPLS_OP_POP; + else + return 0; + } else { + if (family == AF_MPLS) + hdr.rtm_mpls = MPLS_OP_SWAP; + else + hdr.rtm_mpls = MPLS_OP_PUSH; + } } Index: lde_lib.c =================================================================== RCS file: /cvs/src/usr.sbin/ldpd/lde_lib.c,v retrieving revision 1.14 diff -u -r1.14 lde_lib.c --- lde_lib.c 3 Mar 2010 10:17:05 -0000 1.14 +++ lde_lib.c 10 Apr 2010 15:55:57 -0000 @@ -118,7 +118,7 @@ rtctl.local_label = r->local_label; rtctl.remote_label = r->remote_label; - if (!r->present || r->remote_label == NO_LABEL) + if (!r->present) rtctl.in_use = 0; else rtctl.in_use = 1; ------------------------------------------------------------- ldpctl ------------------------------------------------------------- Index: ldpctl.c =================================================================== RCS file: /cvs/src/usr.sbin/ldpctl/ldpctl.c,v retrieving revision 1.8 diff -u -r1.8 ldpctl.c --- ldpctl.c 3 Mar 2010 10:18:35 -0000 1.8 +++ ldpctl.c 10 Apr 2010 15:56:13 -0000 @@ -320,19 +320,29 @@ { struct ctl_rt *rt; char *dstnet, *remote; + int remote_label, no_label; + no_label = ((NO_LABEL << MPLS_LABEL_OFFSET) + & MPLS_LABEL_MASK) >> MPLS_LABEL_OFFSET; switch (imsg->hdr.type) { case IMSG_CTL_SHOW_LIB: rt = imsg->data; if (asprintf(&dstnet, "%s/%d", inet_ntoa(rt->prefix), rt->prefixlen) == -1) err(1, NULL); - - if (rt->connected || !rt->in_use) { + remote_label = ntohl(rt->remote_label) >> MPLS_LABEL_OFFSET; + if (!rt->in_use) { if (asprintf(&remote, "-") == -1) err(1, NULL); + } else if (rt->connected + || (remote_label == no_label)) { + if (asprintf(&remote, "Untagged") == -1) + err(1, NULL); + } else if (remote_label == MPLS_LABEL_IMPLNULL) { + if (asprintf(&remote, "Pop tag") == -1) + err(1, NULL); } else { - if (asprintf(&remote, "%u", (ntohl(rt->remote_label) >> MPLS_LABEL_OFFSET)) == -1) + if (asprintf(&remote, "%u", remote_label) == -1) err(1, NULL); } @@ -429,17 +439,24 @@ else if (k->flags & F_CONNECTED) printf("link#%-13u", k->ifindex); - if (k->local_label != NO_LABEL) { + if (k->local_label == NO_LABEL) { + printf("- "); + } else if (ntohl(k->local_label) >> MPLS_LABEL_OFFSET + == MPLS_LABEL_IMPLNULL) { + printf("imp-null "); + } else printf("%-18u", (ntohl(k->local_label) >> MPLS_LABEL_OFFSET)); - } else - printf("- "); - if (k->remote_label != NO_LABEL) { + if (k->remote_label == NO_LABEL) { + printf("-"); + } else if (htonl(k->remote_label) >> MPLS_LABEL_OFFSET + == MPLS_LABEL_IMPLNULL) { + printf("Pop"); + } else { printf("%u", (ntohl(k->remote_label) >> MPLS_LABEL_OFFSET)); - } else - printf("-"); + } printf("\n"); |
Il giorno dom, 11/04/2010 alle 10.21 +0200, Thomas Habets ha scritto:
> I played around a bit with ospfd and ldpd against real cisco routers, and > noticed some strange things. Glad to see that someone is testing MPLS and ldpd. That is going to help us. Keep in mind that it is still in a development state. > First of all I saw that the output from "ldpctl show lib" and lfib showed label > "3" instead of the well-known "implicit null". I've patched ldpctl to show what > I think is more appropriate output. ldpctl-impnull.patch. This part is going to be committed with some little tweaks. Thanks. > Then I saw that any packet *using* the implicit null label actually went > out over the wire with a label of 3. That's not very implicit. In fact, that's > explicit. > > I added a check to ldpd if it's about to tell the kernel to place an imp-null > label (swap or push, for MPLS and IP) and if so change it to skipping that > label (using pop or return instead). This part is also right. Current ldpd behaviour is just for testing purposes, but a correct PHP would require to pop instead of sending out packets with label 3. Also this part is going to be committed. > Also, I'm not quite sure what "In use" is supposed to mean, since if I take > this line for example: > 123.0.0.1/32 123.0.0.1 23 - no The "in use" column means that we received a label for a prefix that we don't have in the kernel routing table, or that is somehow unusable. I think your diff makes things more clear. Thanks. |
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