MSVSphere Packaging Team
1 year ago
parent
dc36d9af40
commit
e29b5b160d
@ -0,0 +1,255 @@
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From edc3f63167fd95e4e70287743c9b252415c9336e Mon Sep 17 00:00:00 2001
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From: Philippe Guibert <philippe.guibert@6wind.com>
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Date: Thu, 7 Jul 2022 14:33:48 +0200
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Subject: [PATCH] bfdd: allow l3vrf bfd sessions without udp leaking
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Until now, when in vrf-lite mode, the BFD implementation
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creates a single UDP socket and relies on the following
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sysctl value to 1:
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echo 1 > /proc/sys/net/ipv4/udp_l3mdev_accept
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With this setting, the incoming BFD packets from a given
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vrf, would leak to the default vrf, and would match the
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UDP socket.
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The drawback of this solution is that udp packets received
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on a given vrf may leak to an other vrf. This may be a
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security concern.
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The commit addresses this issue by avoiding this leak
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mechanism. An UDP socket is created for each vrf, and each
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socket uses new setsockopt option: SO_REUSEADDR + SO_REUSEPORT.
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With this option, the incoming UDP packets are distributed on
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the available sockets. The impact of those options with l3mdev
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devices is unknown. It has been observed that this option is not
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needed, until the default vrf sockets are created.
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To ensure the BFD packets are correctly routed to the appropriate
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socket, a BPF filter has been put in place and attached to the
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sockets : SO_ATTACH_REUSEPORT_CBPF. This option adds a criterium
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to force the packet to choose a given socket. If initial criteria
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from the default distribution algorithm were not good, at least
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two sockets would be available, and the CBPF would force the
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selection to the same socket. This would come to the situation
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where an incoming packet would be processed on a different vrf.
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The bpf code is the following one:
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struct sock_filter code[] = {
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{ BPF_RET | BPF_K, 0, 0, 0 },
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};
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struct sock_fprog p = {
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.len = sizeof(code)/sizeof(struct sock_filter),
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.filter = code,
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};
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if (setsockopt(sd, SOL_SOCKET, SO_ATTACH_REUSEPORT_CBPF, &p, sizeof(p))) {
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zlog_warn("unable to set SO_ATTACH_REUSEPORT_CBPF on socket: %s",
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strerror(errno));
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return -1;
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}
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Some tests have been done with by creating vrf contexts, and by using
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the below vtysh configuration:
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ip route 2.2.2.2/32 10.126.0.2
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vrf vrf2
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ip route 2.2.2.2/32 10.126.0.2
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!
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interface ntfp2
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ip address 10.126.0.1/24
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!
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interface ntfp3 vrf vrf4
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ip address 10.126.0.1/24
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!
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interface ntfp2 vrf vrf1
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ip address 10.126.0.1/24
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!
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interface ntfp2.100 vrf vrf2
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ip address 10.126.0.1/24
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!
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interface ntfp2.200 vrf vrf3
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ip address 10.126.0.1/24
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!
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line vty
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!
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bfd
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peer 10.126.0.2 vrf vrf2
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!
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peer 10.126.0.2 vrf vrf3
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!
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peer 10.126.0.2
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!
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peer 10.126.0.2 vrf vrf4
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!
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peer 2.2.2.2 multihop local-address 1.1.1.1
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!
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peer 2.2.2.2 multihop local-address 1.1.1.1 vrf vrf2
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transmit-interval 1500
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receive-interval 1500
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!
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The results showed no issue related to packets received by
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the wrong vrf. Even changing the udp_l3mdev_accept flag to
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1 did not change the test results.
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Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
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---
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bfdd/bfd.c | 66 +++++++++++++++++++++++------------------------
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bfdd/bfd_packet.c | 45 ++++++++++++++++++++++++++++++++
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2 files changed, 77 insertions(+), 34 deletions(-)
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diff --git a/bfdd/bfd.c b/bfdd/bfd.c
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index 483beb1b17c..a1619263588 100644
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--- a/bfdd/bfd.c
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+++ b/bfdd/bfd.c
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@@ -1950,40 +1950,38 @@ static int bfd_vrf_enable(struct vrf *vrf)
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if (bglobal.debug_zebra)
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zlog_debug("VRF enable add %s id %u", vrf->name, vrf->vrf_id);
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- if (vrf->vrf_id == VRF_DEFAULT ||
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- vrf_get_backend() == VRF_BACKEND_NETNS) {
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- if (!bvrf->bg_shop)
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- bvrf->bg_shop = bp_udp_shop(vrf);
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- if (!bvrf->bg_mhop)
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- bvrf->bg_mhop = bp_udp_mhop(vrf);
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- if (!bvrf->bg_shop6)
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- bvrf->bg_shop6 = bp_udp6_shop(vrf);
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- if (!bvrf->bg_mhop6)
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- bvrf->bg_mhop6 = bp_udp6_mhop(vrf);
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- if (!bvrf->bg_echo)
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- bvrf->bg_echo = bp_echo_socket(vrf);
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- if (!bvrf->bg_echov6)
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- bvrf->bg_echov6 = bp_echov6_socket(vrf);
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-
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- if (!bvrf->bg_ev[0] && bvrf->bg_shop != -1)
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- thread_add_read(master, bfd_recv_cb, bvrf,
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- bvrf->bg_shop, &bvrf->bg_ev[0]);
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- if (!bvrf->bg_ev[1] && bvrf->bg_mhop != -1)
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- thread_add_read(master, bfd_recv_cb, bvrf,
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- bvrf->bg_mhop, &bvrf->bg_ev[1]);
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- if (!bvrf->bg_ev[2] && bvrf->bg_shop6 != -1)
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- thread_add_read(master, bfd_recv_cb, bvrf,
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- bvrf->bg_shop6, &bvrf->bg_ev[2]);
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- if (!bvrf->bg_ev[3] && bvrf->bg_mhop6 != -1)
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- thread_add_read(master, bfd_recv_cb, bvrf,
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- bvrf->bg_mhop6, &bvrf->bg_ev[3]);
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- if (!bvrf->bg_ev[4] && bvrf->bg_echo != -1)
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- thread_add_read(master, bfd_recv_cb, bvrf,
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- bvrf->bg_echo, &bvrf->bg_ev[4]);
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- if (!bvrf->bg_ev[5] && bvrf->bg_echov6 != -1)
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- thread_add_read(master, bfd_recv_cb, bvrf,
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- bvrf->bg_echov6, &bvrf->bg_ev[5]);
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- }
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+ if (!bvrf->bg_shop)
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+ bvrf->bg_shop = bp_udp_shop(vrf);
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+ if (!bvrf->bg_mhop)
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+ bvrf->bg_mhop = bp_udp_mhop(vrf);
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+ if (!bvrf->bg_shop6)
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+ bvrf->bg_shop6 = bp_udp6_shop(vrf);
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+ if (!bvrf->bg_mhop6)
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+ bvrf->bg_mhop6 = bp_udp6_mhop(vrf);
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+ if (!bvrf->bg_echo)
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+ bvrf->bg_echo = bp_echo_socket(vrf);
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+ if (!bvrf->bg_echov6)
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+ bvrf->bg_echov6 = bp_echov6_socket(vrf);
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+
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+ if (!bvrf->bg_ev[0] && bvrf->bg_shop != -1)
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+ thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_shop,
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+ &bvrf->bg_ev[0]);
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+ if (!bvrf->bg_ev[1] && bvrf->bg_mhop != -1)
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+ thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_mhop,
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+ &bvrf->bg_ev[1]);
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+ if (!bvrf->bg_ev[2] && bvrf->bg_shop6 != -1)
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+ thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_shop6,
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+ &bvrf->bg_ev[2]);
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+ if (!bvrf->bg_ev[3] && bvrf->bg_mhop6 != -1)
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+ thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_mhop6,
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+ &bvrf->bg_ev[3]);
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+ if (!bvrf->bg_ev[4] && bvrf->bg_echo != -1)
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+ thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_echo,
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+ &bvrf->bg_ev[4]);
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+ if (!bvrf->bg_ev[5] && bvrf->bg_echov6 != -1)
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+ thread_add_read(master, bfd_recv_cb, bvrf, bvrf->bg_echov6,
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+ &bvrf->bg_ev[5]);
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+
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if (vrf->vrf_id != VRF_DEFAULT) {
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bfdd_zclient_register(vrf->vrf_id);
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bfdd_sessions_enable_vrf(vrf);
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diff --git a/bfdd/bfd_packet.c b/bfdd/bfd_packet.c
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index d34d6427628..054a9bfbf21 100644
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--- a/bfdd/bfd_packet.c
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+++ b/bfdd/bfd_packet.c
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@@ -876,6 +876,14 @@ void bfd_recv_cb(struct thread *t)
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"no session found");
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return;
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}
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+ /*
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+ * We may have a situation where received packet is on wrong vrf
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+ */
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+ if (bfd && bfd->vrf && bfd->vrf != bvrf->vrf) {
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+ cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
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+ "wrong vrfid.");
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+ return;
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+ }
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/* Ensure that existing good sessions are not overridden. */
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if (!cp->discrs.remote_discr && bfd->ses_state != PTM_BFD_DOWN &&
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@@ -1208,10 +1216,41 @@ int bp_set_tos(int sd, uint8_t value)
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return 0;
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}
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+static bool bp_set_reuse_addr(int sd)
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+{
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+ int one = 1;
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+
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+ if (setsockopt(sd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) == -1) {
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+ zlog_warn("set-reuse-addr: setsockopt(SO_REUSEADDR, %d): %s",
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+ one, strerror(errno));
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+ return false;
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+ }
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+ return true;
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+}
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+
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+static bool bp_set_reuse_port(int sd)
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+{
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+ int one = 1;
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+
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+ if (setsockopt(sd, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one)) == -1) {
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+ zlog_warn("set-reuse-port: setsockopt(SO_REUSEPORT, %d): %s",
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+ one, strerror(errno));
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+ return false;
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+ }
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+ return true;
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+}
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+
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+
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static void bp_set_ipopts(int sd)
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{
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int rcvttl = BFD_RCV_TTL_VAL;
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+ if (!bp_set_reuse_addr(sd))
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+ zlog_fatal("set-reuse-addr: failed");
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+
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+ if (!bp_set_reuse_port(sd))
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+ zlog_fatal("set-reuse-port: failed");
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+
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if (bp_set_ttl(sd, BFD_TTL_VAL) != 0)
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zlog_fatal("set-ipopts: TTL configuration failed");
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@@ -1453,6 +1492,12 @@ static void bp_set_ipv6opts(int sd)
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int ipv6_pktinfo = BFD_IPV6_PKT_INFO_VAL;
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int ipv6_only = BFD_IPV6_ONLY_VAL;
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+ if (!bp_set_reuse_addr(sd))
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+ zlog_fatal("set-reuse-addr: failed");
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+
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+ if (!bp_set_reuse_port(sd))
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+ zlog_fatal("set-reuse-port: failed");
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+
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if (bp_set_ttlv6(sd, BFD_TTL_VAL) == -1)
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zlog_fatal(
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"set-ipv6opts: setsockopt(IPV6_UNICAST_HOPS, %d): %s",
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@ -0,0 +1,162 @@
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## <summary>policy for frr</summary>
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########################################
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## <summary>
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## Execute frr_exec_t in the frr domain.
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## </summary>
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## <param name="domain">
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## <summary>
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## Domain allowed to transition.
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## </summary>
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## </param>
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#
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interface(`frr_domtrans',`
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gen_require(`
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type frr_t, frr_exec_t;
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')
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corecmd_search_bin($1)
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domtrans_pattern($1, frr_exec_t, frr_t)
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')
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######################################
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## <summary>
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## Execute frr in the caller domain.
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## </summary>
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## <param name="domain">
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## <summary>
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## Domain allowed access.
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## </summary>
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## </param>
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#
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interface(`frr_exec',`
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gen_require(`
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type frr_exec_t;
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')
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corecmd_search_bin($1)
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can_exec($1, frr_exec_t)
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')
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########################################
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## <summary>
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## Read frr's log files.
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## </summary>
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## <param name="domain">
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## <summary>
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## Domain allowed access.
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## </summary>
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## </param>
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## <rolecap/>
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#
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interface(`frr_read_log',`
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gen_require(`
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type frr_log_t;
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')
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read_files_pattern($1, frr_log_t, frr_log_t)
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optional_policy(`
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logging_search_logs($1)
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')
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')
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########################################
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## <summary>
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## Append to frr log files.
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## </summary>
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## <param name="domain">
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## <summary>
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## Domain allowed access.
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## </summary>
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## </param>
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#
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interface(`frr_append_log',`
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gen_require(`
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type frr_log_t;
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')
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append_files_pattern($1, frr_log_t, frr_log_t)
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optional_policy(`
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logging_search_logs($1)
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')
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')
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########################################
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## <summary>
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## Manage frr log files
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## </summary>
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## <param name="domain">
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## <summary>
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## Domain allowed access.
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## </summary>
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## </param>
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#
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interface(`frr_manage_log',`
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gen_require(`
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type frr_log_t;
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')
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manage_dirs_pattern($1, frr_log_t, frr_log_t)
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manage_files_pattern($1, frr_log_t, frr_log_t)
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manage_lnk_files_pattern($1, frr_log_t, frr_log_t)
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optional_policy(`
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logging_search_logs($1)
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')
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')
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########################################
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## <summary>
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## Read frr PID files.
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## </summary>
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## <param name="domain">
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## <summary>
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## Domain allowed access.
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## </summary>
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## </param>
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#
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interface(`frr_read_pid_files',`
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gen_require(`
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type frr_var_run_t;
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')
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files_search_pids($1)
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read_files_pattern($1, frr_var_run_t, frr_var_run_t)
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')
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########################################
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## <summary>
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## All of the rules required to administrate
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## an frr environment
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## </summary>
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## <param name="domain">
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## <summary>
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## Domain allowed access.
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## </summary>
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## </param>
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#
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interface(`frr_admin',`
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gen_require(`
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type frr_t;
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type frr_log_t;
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type frr_var_run_t;
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')
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allow $1 frr_t:process { signal_perms };
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ps_process_pattern($1, frr_t)
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tunable_policy(`deny_ptrace',`',`
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allow $1 frr_t:process ptrace;
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')
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admin_pattern($1, frr_log_t)
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files_search_pids($1)
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admin_pattern($1, frr_var_run_t)
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optional_policy(`
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logging_search_logs($1)
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')
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optional_policy(`
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systemd_passwd_agent_exec($1)
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systemd_read_fifo_file_passwd_run($1)
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')
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')
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