On Mon, 2021-03-15 at 17:26 +0100, Joakim Tjernlund wrote:
On Mon, 2021-03-15 at 15:59 +0100, Ondrej Zajicek wrote:
On Mon, Mar 15, 2021 at 02:25:18PM +0000, Kenth Eriksson wrote:
I believe the "options" of the neighbor object is only updated as a result of NEIGHBOR_EXSTART. If the authentication is enabled after unauthenticated neighbor adjacency, then this does not result in a new NEIGHBOR_EXSTART. Thus the options of the neighbor object is stuck 0x113, and not the updated to 0x513 (i.e. OPT_AT) resulting in that OSPF packets are becoming dropped in procedure ospf_pkt_checkauth3 since auth_present is zero.
Yes, you are right. If iface is configured to not use auth, adjacency is established (n->options are set to not include OPT_AT) and then reconfigured to use auth, adjacency is kept (because Hello packets are authenticated) but LSUpd and others are ignored (because there is no OPT_AT flag in n->options).
RFC 7166 is vague about updating OPT_AT flag, and basic OSPFv2/v3 RFC just describing setting n->options from DBDes during NEIGHBOR_EXSTART.
If I manually kick the FSM when authentication is changed by doing ISM_DOWN-> ISM_UP then this works as expected (see pseudo code below). I believe there is some logic missing when changing the autype? Can this be done in some more fine granular way?
I think that the best solution would be to update OPT_AT flag in n->options based on received Hello packets. Will make a patch.
Are you thinking something like this?
diff --git a/proto/ospf/hello.c b/proto/ospf/hello.c index d094f934..dc3bc912 100644 --- a/proto/ospf/hello.c +++ b/proto/ospf/hello.c @@ -253,6 +253,10 @@ ospf_receive_hello(struct ospf_packet *pkt, struct ospf_iface *ifa,
neighbors = ps->neighbors; neigh_count = (plen - sizeof(struct ospf_hello3_packet)) / sizeof(u32); + if (rcv_options & OPT_AT) + n->options |= OPT_AT; + else + n->options &= ~OPT_AT; }
That did a SEGV on a NULL nbr ... Now running this: diff --git a/proto/ospf/hello.c b/proto/ospf/hello.c index d094f934..e103d2fd 100644 --- a/proto/ospf/hello.c +++ b/proto/ospf/hello.c @@ -341,6 +341,11 @@ ospf_receive_hello(struct ospf_packet *pkt, struct ospf_ifa ce *ifa, n->bdr = rcv_bdr; n->priority = rcv_priority; n->iface_id = rcv_iface_id; + if (ospf_is_v3(p)) + if (rcv_options & OPT_AT) + n->options |= OPT_AT; + else + n->options &= ~OPT_AT; /* Update inactivity timer */ ospf_neigh_sm(n, INM_HELLOREC); --