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| author | Donald Sharp <sharpd@cumulusnetworks.com> | 2015-07-02 19:22:49 +0200 |
|---|---|---|
| committer | Donald Sharp <sharpd@cumulusnetwroks.com> | 2016-05-26 02:38:33 +0200 |
| commit | c29c0f61de9d8ae208aeffe919942b113f3271d4 (patch) | |
| tree | 0431b40d7cc623b310087f4b0d0ce11202c327f0 /pimd/pim_pim.c | |
| parent | pimd: Stop DR election on every hello (diff) | |
| download | frr-c29c0f61de9d8ae208aeffe919942b113f3271d4.tar.xz frr-c29c0f61de9d8ae208aeffe919942b113f3271d4.zip | |
pimd: Ensure new generation_id is different from previous
The RFC states that an interfaces generation_id must be changed
if it experiences an if down. From 4.3.1:
The GenID option contains a randomly generated
32-bit value that is regenerated each time PIM forwarding is started
or restarted on the interface, including when the router itself
restarts.
Since we are only grabbing a new generation_id without comparing
it to the previous generation_id, it is possible that random
can generate the exact same number.
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
Diffstat (limited to 'pimd/pim_pim.c')
| -rw-r--r-- | pimd/pim_pim.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/pimd/pim_pim.c b/pimd/pim_pim.c index 7dcb50199..41c26a888 100644 --- a/pimd/pim_pim.c +++ b/pimd/pim_pim.c @@ -698,6 +698,7 @@ int pim_sock_add(struct interface *ifp) { struct pim_interface *pim_ifp; struct in_addr ifaddr; + uint32_t old_genid; pim_ifp = ifp->info; zassert(pim_ifp); @@ -720,7 +721,18 @@ int pim_sock_add(struct interface *ifp) pim_ifp->t_pim_sock_read = 0; pim_ifp->pim_sock_creation = pim_time_monotonic_sec(); - pim_ifp->pim_generation_id = random(); + /* + * Just ensure that the new generation id + * actually chooses something different. + * Actually ran across a case where this + * happened, pre-switch to random(). + * While this is unlikely to happen now + * let's make sure it doesn't. + */ + old_genid = pim_ifp->pim_generation_id; + + while (old_genid == pim_ifp->pim_generation_id) + pim_ifp->pim_generation_id = random(); zlog_info("PIM INTERFACE UP: on interface %s ifindex=%d", ifp->name, ifp->ifindex); |