Currently bgp does not stop any events that are on the thread
system for execution on peer deletion. This is not good.
Stop those events and prevent use after free's.
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
When the decision has been made to copy a peer configuration from
a peer to another peer because one is taking over. Do not automatically
set the CONFIG_NODE flag. Instead we need to handle that appropriately
when the final decision is made to transfer.
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
When changing the peers sockunion structure the bgp->peer
list was not being updated properly. Since the peer's su
is being used for a sorted insert then the change of it requires
that the value be pulled out of the bgp->peer list and then
put back into as well.
Additionally ensure that the hash is always released on peer
deletion.
Lead to this from this decode in a address sanitizer run.
=================================================================
==30778==ERROR: AddressSanitizer: heap-use-after-free on address 0x62a0000d8440 at pc 0x7f48c9c5c547 bp 0x7ffcba272cb0 sp 0x7ffcba272ca8
READ of size 2 at 0x62a0000d8440 thread T0
#0 0x7f48c9c5c546 in sockunion_same lib/sockunion.c:425
#1 0x55cfefe3000f in peer_hash_same bgpd/bgpd.c:890
#2 0x7f48c9bde039 in hash_release lib/hash.c:209
#3 0x55cfefe3373f in bgp_peer_conf_if_to_su_update bgpd/bgpd.c:1541
#4 0x55cfefd0be7a in bgp_stop bgpd/bgp_fsm.c:1631
#5 0x55cfefe4028f in peer_delete bgpd/bgpd.c:2362
#6 0x55cfefdd5e97 in no_neighbor_interface_config bgpd/bgp_vty.c:4267
#7 0x7f48c9b9d160 in cmd_execute_command_real lib/command.c:949
#8 0x7f48c9ba1112 in cmd_execute_command lib/command.c:1009
#9 0x7f48c9ba1573 in cmd_execute lib/command.c:1162
#10 0x7f48c9c87402 in vty_command lib/vty.c:526
#11 0x7f48c9c87832 in vty_execute lib/vty.c:1291
#12 0x7f48c9c8e741 in vtysh_read lib/vty.c:2130
#13 0x7f48c9c7a66d in thread_call lib/thread.c:1585
#14 0x7f48c9bf64e7 in frr_run lib/libfrr.c:1123
#15 0x55cfefc75a15 in main bgpd/bgp_main.c:540
#16 0x7f48c96b009a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a)
#17 0x55cfefc787f9 in _start (/usr/lib/frr/bgpd+0xe27f9)
0x62a0000d8440 is located 576 bytes inside of 23376-byte region [0x62a0000d8200,0x62a0000ddd50)
freed by thread T0 here:
#0 0x7f48c9eb9fb0 in __interceptor_free (/lib/x86_64-linux-gnu/libasan.so.5+0xe8fb0)
#1 0x55cfefe3fe42 in peer_free bgpd/bgpd.c:1113
#2 0x55cfefe3fe42 in peer_unlock_with_caller bgpd/bgpd.c:1144
#3 0x55cfefe4092e in peer_delete bgpd/bgpd.c:2457
#4 0x55cfefdd5e97 in no_neighbor_interface_config bgpd/bgp_vty.c:4267
#5 0x7f48c9b9d160 in cmd_execute_command_real lib/command.c:949
#6 0x7f48c9ba1112 in cmd_execute_command lib/command.c:1009
#7 0x7f48c9ba1573 in cmd_execute lib/command.c:1162
#8 0x7f48c9c87402 in vty_command lib/vty.c:526
#9 0x7f48c9c87832 in vty_execute lib/vty.c:1291
#10 0x7f48c9c8e741 in vtysh_read lib/vty.c:2130
#11 0x7f48c9c7a66d in thread_call lib/thread.c:1585
#12 0x7f48c9bf64e7 in frr_run lib/libfrr.c:1123
#13 0x55cfefc75a15 in main bgpd/bgp_main.c:540
#14 0x7f48c96b009a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a)
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
When a peer is a peer-group based peer, and the config is inherited
from the peer group, let's ensure that the CONFIG_NODE flag stays
no matter what.
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
Three fixes:
a) When calling bgp_fsm_change_status with `Deleted` do
not add a new event to the peer's t_event because
we are already in the process of deleting everything
b) When bgp_stop decides to delete a peer return a notification
that it is happening to bgp_event_update so that it does not
set the peer state back to idle or do other processing.
c) bgp_event_update can cause a peer deletion, because
the peer can be deleted in the fsm function but the peer
data structure is still pointed to and used after words.
So lock the peer before entering and prevent a use after
free.
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
At some point in the past the peer creation was not
properly setting the su and the code had the release
and re-add when setting the su. Since peer_create
got a bit of code to handle the su properly the
need to release then add it back in is negated
so remove the code.
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
When multiple daemons report a exit line for the same
node, vtysh was just dropping the previous pointer.
Ensure that we free it first.
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
On shutdown a use after free was being seen of a route table.
Basically the pointer was kept around and resent for cleanup.
Probably something needs to be unwound to make this better
in the future. Just cleaning up the use after free.
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929-=================================================================
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929:==911929==ERROR: AddressSanitizer: heap-use-after-free on address 0x606000127a00 at pc 0x7fb9ad546f5b bp 0x7ffc3cff0330 sp 0x7ffc3
cff0328
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929-READ of size 8 at 0x606000127a00 thread T0
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #0 0x7fb9ad546f5a in route_table_free /home/sharpd/frr8/lib/table.c:103:13
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #1 0x7fb9ad546f04 in route_table_finish /home/sharpd/frr8/lib/table.c:61:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #2 0x6b94ba in zebra_ns_disable_internal /home/sharpd/frr8/zebra/zebra_ns.c:141:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #3 0x6b9158 in zebra_ns_disabled /home/sharpd/frr8/zebra/zebra_ns.c:116:9
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #4 0x7fb9ad43f0f5 in ns_disable_internal /home/sharpd/frr8/lib/netns_linux.c:273:4
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #5 0x7fb9ad43e634 in ns_disable /home/sharpd/frr8/lib/netns_linux.c:368:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #6 0x7fb9ad43e251 in ns_delete /home/sharpd/frr8/lib/netns_linux.c:330:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #7 0x7fb9ad43fbb3 in ns_terminate /home/sharpd/frr8/lib/netns_linux.c:524:3
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #8 0x54f8de in zebra_finalize /home/sharpd/frr8/zebra/main.c:232:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #9 0x7fb9ad5655e6 in thread_call /home/sharpd/frr8/lib/thread.c:2006:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #10 0x7fb9ad3d3343 in frr_run /home/sharpd/frr8/lib/libfrr.c:1198:3
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #11 0x550b48 in main /home/sharpd/frr8/zebra/main.c:476:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #12 0x7fb9acd30d09 in __libc_start_main csu/../csu/libc-start.c:308:16
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #13 0x443549 in _start (/usr/lib/frr/zebra+0x443549)
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929-
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929-0x606000127a00 is located 0 bytes inside of 56-byte region [0x606000127a00,0x606000127a38)
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929-freed by thread T0 here:
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #0 0x4bd33d in free (/usr/lib/frr/zebra+0x4bd33d)
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #1 0x7fb9ad42cc80 in qfree /home/sharpd/frr8/lib/memory.c:141:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #2 0x7fb9ad547305 in route_table_free /home/sharpd/frr8/lib/table.c:141:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #3 0x7fb9ad546f04 in route_table_finish /home/sharpd/frr8/lib/table.c:61:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #4 0x6b94ba in zebra_ns_disable_internal /home/sharpd/frr8/zebra/zebra_ns.c:141:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #5 0x6b9692 in zebra_ns_early_shutdown /home/sharpd/frr8/zebra/zebra_ns.c:164:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #6 0x7fb9ad43f228 in ns_walk_func /home/sharpd/frr8/lib/netns_linux.c:386:9
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #7 0x55014f in sigint /home/sharpd/frr8/zebra/main.c:194:2
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #8 0x7fb9ad50db99 in frr_sigevent_process /home/sharpd/frr8/lib/sigevent.c:130:6
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #9 0x7fb9ad560d07 in thread_fetch /home/sharpd/frr8/lib/thread.c:1775:4
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #10 0x7fb9ad3d332d in frr_run /home/sharpd/frr8/lib/libfrr.c:1197:9
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #11 0x550b48 in main /home/sharpd/frr8/zebra/main.c:476:2
--
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929- #7 0x7fb9acd30d09 in __libc_start_main csu/../csu/libc-start.c:308:16
./bfd_vrf_topo1.test_bfd_vrf_topo1/r2.zebra.asan.911929-
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
Config data was being freed just prior to it
being used for cleanup in shutdown. Prevent this
from happening.
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142-=================================================================
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142:==2274142==ERROR: AddressSanitizer: heap-use-after-free on address 0x61d00000c880 at pc 0x0000004d94d1 bp 0x7ffd46637810 sp 0
x7ffd46637808
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142-READ of size 4 at 0x61d00000c880 thread T0
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #0 0x4d94d0 in ldp_rtr_id_get /home/sharpd/frr8/ldpd/ldpd.c:983:20
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #1 0x56ff92 in gen_ldp_hdr /home/sharpd/frr8/ldpd/packet.c:47:19
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #2 0x56a4b0 in send_notification_full /home/sharpd/frr8/ldpd/notification.c:49:9
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #3 0x56c4b3 in send_notification /home/sharpd/frr8/ldpd/notification.c:117:2
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #4 0x573fb7 in session_shutdown /home/sharpd/frr8/ldpd/packet.c:666:3
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #5 0x4e2ef1 in adj_del /home/sharpd/frr8/ldpd/adjacency.c:145:3
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #6 0x55d425 in ldpe_shutdown /home/sharpd/frr8/ldpd/ldpe.c:231:3
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #7 0x55a9a0 in ldpe_dispatch_main /home/sharpd/frr8/ldpd/ldpe.c:631:3
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #8 0x7f0c00c035e6 in thread_call /home/sharpd/frr8/lib/thread.c:2006:2
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #9 0x5586f2 in ldpe /home/sharpd/frr8/ldpd/ldpe.c:138:3
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #10 0x4d46d2 in main /home/sharpd/frr8/ldpd/ldpd.c:339:3
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #11 0x7f0c00476d09 in __libc_start_main csu/../csu/libc-start.c:308:16
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #12 0x429cb9 in _start (/usr/lib/frr/ldpd+0x429cb9)
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142-
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142-0x61d00000c880 is located 0 bytes inside of 2008-byte region [0x61d00000c880,0x61d00000d058)
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142-freed by thread T0 here:
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #0 0x4a3aad in free (/usr/lib/frr/ldpd+0x4a3aad)
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #1 0x4de6c8 in config_clear /home/sharpd/frr8/ldpd/ldpd.c:2001:2
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #2 0x55d12d in ldpe_shutdown /home/sharpd/frr8/ldpd/ldpe.c:211:2
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #3 0x55a9a0 in ldpe_dispatch_main /home/sharpd/frr8/ldpd/ldpe.c:631:3
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #4 0x7f0c00c035e6 in thread_call /home/sharpd/frr8/lib/thread.c:2006:2
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #5 0x5586f2 in ldpe /home/sharpd/frr8/ldpd/ldpe.c:138:3
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #6 0x4d46d2 in main /home/sharpd/frr8/ldpd/ldpd.c:339:3
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #7 0x7f0c00476d09 in __libc_start_main csu/../csu/libc-start.c:308:16
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142-
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142-previously allocated by thread T0 here:
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #0 0x4a3ea2 in calloc (/usr/lib/frr/ldpd+0x4a3ea2)
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #1 0x4d6146 in config_new_empty /home/sharpd/frr8/ldpd/ldpd.c:1967:10
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #2 0x558678 in ldpe /home/sharpd/frr8/ldpd/ldpe.c:134:11
--
./isis_rlfa_topo1.test_isis_rlfa_topo1/rt8.ldpd.asan.2274142- #4 0x7f0c00476d09 in __libc_start_main csu/../csu/libc-start.c:308:16
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
It's possible to send less data then the length you say you are.
Reported-by: Iggy Frankovic <iggyfran@amazon.com>
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
The rl_callback_handler_install function manual says this:
Set up the terminal for Readline I/O and display the initial expanded value of prompt.
Save the value of lhandler to use as a handler function to call when a complete line
of input has been entered. The handler function receives the text of the line as an
argument. As with readline(), the handler function should free the line when it is
finished with it.
Adding a free removes this memory leak that I am seeing with address sanitizer enabled;
SUMMARY: AddressSanitizer: 99 byte(s) leaked in 5 allocation(s).:
2022-12-05 07:50:57,231 INFO: topolog.r7: vtysh result:
Hello, this is FRRouting (version 8.5-dev).
Copyright 1996-2005 Kunihiro Ishiguro, et al.
r7# clear log cmdline-targets
r7# conf t
r7(config)# log file staticd.log debug
r7(config)# log commands
r7(config)# log timestamp precision 3
r7(config)#
=================================================================
==976989==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 99 byte(s) in 5 object(s) allocated from:
#0 0x49cadd in malloc (/usr/bin/vtysh+0x49cadd)
#1 0x7fc57135d8e8 in xmalloc build/shlib/./xmalloc.c:59:10
SUMMARY: AddressSanitizer: 99 byte(s) leaked in 5 allocation(s).
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
The `behavior usid` command is installed under the SRv6 Locator node in
the zebra VTY. However, in the SRv6 config write function this command
is wrongly put on the same line as the `prefix X:X::X:X/M` command.
This causes a failure when an SRv6 uSID locator is configured in zebra
and `frr-reload.py` is used to reload the FRR configuration.
This commit prepends a newline character to the `behavior usid` command
in the SRv6 config write function. The output of `show running-config`
before and after this commit is shown below.
Before:
```
Building configuration...
Current configuration:
!
frr version 8.5-dev
!
segment-routing
srv6
locators
locator loc1
prefix fc00:0:1::/48 block-len 32 node-len 16 behavior usid
exit
!
exit
!
exit
!
exit
!
end
```
After:
```
Building configuration...
Current configuration:
!
segment-routing
srv6
locators
locator loc1
prefix fc00:0:1::/48 block-len 32 node-len 16
behavior usid
exit
!
exit
!
exit
!
exit
!
end
```
Signed-off-by: Carmine Scarpitta <carmine.scarpitta@uniroma2.it>
Documentation ways that community-list works as OR when multiple community
values specified per entry, but it's wrong. It must be AND, let's fix this.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
frrouting/frr:master will be generated every day
frrouting/frr:vX.Y.Z will be generated every time a new push is done on the
stable/X.Y branch.
Takes up to 3 hours to build and publish images.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
When we use vrf-to-vrf export, the nexthop has already not been
overridden when the peer is BGP unnumberred. However, when we use normal
export, the nexthop will be oberridden. This behavior will make the VPN
routes invalid in VPN RIB.
This PR stops overriding nexthop even if we use normal export.
Signed-off-by: Ryoga Saito <ryoga.saito@linecorp.com>
The first argument of sid_unregister should be default bgp instance.
However, these functions passed VRF bgp instance to this funciton.
Signed-off-by: Ryoga Saito <ryoga.saito@linecorp.com>
In bgp_srv6l3vpn tests, check_ping checks reachability. However, this
function have a bug and if we set expect_connected to True, check will
pass even if all ping packets are lost. This commit fixes this issue.
Signed-off-by: Ryoga Saito <ryoga.saito@linecorp.com>
This commit eaeba5e868 changed a bit a formatting,
but this part was missed, let's fix it.
An example before the patch:
```
r3# sh ip bgp ipv4 labeled-unicast neighbors 192.168.34.4 advertised-routes
BGP table version is 3, local router ID is 192.168.34.3, vrf id 0
Default local pref 100, local AS 65003
Status codes: s suppressed, d damped, h history, * valid, > best, = multipath,
i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
*> 10.0.0.1/32 0.0.0.0 0 65001 ?
Total number of prefixes 1
```
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
The `bgp_srv6l3vpn_to_bgp_vrf2` topotest tests the SRv6 IPv4 L3VPN
functionality. It applies the appropriate configuration in `bgpd` and
`zebra`, and then checks that the RIB is updated correctly.
The topotest expects to find the AS-Path in the RIB, which is only
present if the `bgp send-extra-data zebra` option is enabled in the
`bgpd` configuration.
Currently, the `bgp send-extra-data zebra` option is not set in the
`bgpd` configuration, which always causes the topotest to fail.
This commit fixes the `bgp_srv6l3vpn_to_bgp_vrf2` topotest by enabling
the `bgp send-extra-data zebra` option for both routers `r1` and `r2`.
Signed-off-by: Carmine Scarpitta <carmine.scarpitta@uniroma2.it>
Add "show motd" commad.
The vtysh user can call the "show motd" command to re-show the welcome message.
This is necessary if the user saves frequently used commands in motd.
Signed-off-by: Sergei Rozhkov <gh@zserg.ru>
Use %pI4/%pI6 where possible, otherwise at least atjust stack buffer sizes
for inet_ntop() calls.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
bgp_pcount_adjust() is called only when calling bgp_path_info_set_flag().
Before this patch the pcount is not advanced before checking for overflow.
Additionally, print:
```
[RZMGQ-A03CG] 192.168.255.1(r1) rcvd UPDATE about 172.16.255.254/32 IPv4 unicast -- DENIED due to: maximum-prefix overflow
```
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
