Bug 1956209
| Summary: | dhclient -6 -P ppp0 does not complete prefix acquire | ||
|---|---|---|---|
| Product: | [Fedora] Fedora | Reporter: | udo <udovdh> |
| Component: | dhcp | Assignee: | Martin Osvald 🛹 <mosvald> |
| Status: | CLOSED EOL | QA Contact: | Fedora Extras Quality Assurance <extras-qa> |
| Severity: | urgent | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | 34 | CC: | mosvald, pemensik, pzhukov |
| Target Milestone: | --- | Keywords: | Reopened |
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2022-06-08 00:06:46 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
|
Description
udo
2021-05-03 08:15:57 UTC
BTW: `man 8 dhclient-script` does not really mention the ipv6 cases, dhclient.d, etc. firewall off does not matter. We do have active VDSL connection, indicated by ipv4 ping. Questions that come to mind: What is unacceptable in the dhcp-server responses that apparently reach dhclient? (see `strace`) Why isn't this logged? It would be helpful to know what is wrong... Why doesn't -v help here? How to debug this? Adding log_debug's to any receive-related functions in dhc6.c does not reveal any activity in those funcions. What is the right spot to check if the packets from the dhcp server actually reach dhclient? (Although firewall off makes no difference and we have the tcpdump...) What Is ee after adding the log_debugs: # ./dhclient -6 -P ppp0 -v -d dhcpv6_client_assignments Internet Systems Consortium DHCP Client 4.4.2b1 Copyright 2004-2019 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on Socket/ppp0 Sending on Socket/ppp0 xid: rand init seed (0x9cfbab24) built using all available interfaces PRC: Soliciting for leases (INIT). dhc6_retrans_init dhc6_rand do_init6 check_timing6 XMT: Forming Solicit, 0 ms elapsed. make_client6_options dhc6_create_iaid XMT: X-- IA_PD 00:00:00:00 XMT: | X-- Request renew in +3600 XMT: | X-- Request rebind in +5400 XMT: Solicit on ppp0, interval 1080ms. dhc6_retrans_advance dhc6_rand do_init6 check_timing6 XMT: Forming Solicit, 1080 ms elapsed. make_client6_options dhc6_create_iaid XMT: X-- IA_PD 00:00:00:00 XMT: | X-- Request renew in +3600 XMT: | X-- Request rebind in +5400 XMT: Solicit on ppp0, interval 2070ms. dhc6_retrans_advance dhc6_rand do_init6 check_timing6 XMT: Forming Solicit, 3150 ms elapsed. make_client6_options dhc6_create_iaid XMT: X-- IA_PD 00:00:00:00 XMT: | X-- Request renew in +3600 XMT: | X-- Request rebind in +5400 XMT: Solicit on ppp0, interval 4150ms. dhc6_retrans_advance dhc6_rand do_init6 check_timing6 XMT: Forming Solicit, 7310 ms elapsed. make_client6_options dhc6_create_iaid XMT: X-- IA_PD 00:00:00:00 XMT: | X-- Request renew in +3600 XMT: | X-- Request rebind in +5400 XMT: Solicit on ppp0, interval 8190ms. dhc6_retrans_advance dhc6_rand do_init6 check_timing6 XMT: Forming Solicit, 15500 ms elapsed. make_client6_options dhc6_create_iaid XMT: X-- IA_PD 00:00:00:00 XMT: | X-- Request renew in +3600 XMT: | X-- Request rebind in +5400 XMT: Solicit on ppp0, interval 16810ms. dhc6_retrans_advance dhc6_rand do_init6 check_timing6 XMT: Forming Solicit, 32320 ms elapsed. make_client6_options dhc6_create_iaid XMT: X-- IA_PD 00:00:00:00 XMT: | X-- Request renew in +3600 XMT: | X-- Request rebind in +5400 XMT: Solicit on ppp0, interval 32850ms. dhc6_retrans_advance dhc6_rand do_init6 check_timing6 XMT: Forming Solicit, 65170 ms elapsed. make_client6_options dhc6_create_iaid XMT: X-- IA_PD 00:00:00:00 XMT: | X-- Request renew in +3600 XMT: | X-- Request rebind in +5400 XMT: Solicit on ppp0, interval 67850ms. dhc6_retrans_advance dhc6_rand dhc6_rand ^C # While running tcpdump partly through this sequence: # tcpdump -i ppp0 -v port 546 dropped privs to tcpdump tcpdump: listening on ppp0, link-type LINUX_SLL (Linux cooked v1), snapshot length 262144 bytes 12:39:28.452817 IP6 (flowlabel 0x0133d, hlim 1, next-header UDP (17) payload length: 60) vuurmuur.dhcpv6-client > ff02::1:2.dhcpv6-server: [udp sum ok] dhcp6 solicit (xid=99c6e1 (client-ID hwaddr/time type 1 time 394565497 004063f60200) (option-request DNS-server DNS-search-list) (elapsed-time 3232) (IA_PD IAID:0 T1:3600 T2:5400)) 12:39:28.468153 IP6 (class 0xc0, hlim 64, next-header UDP (17) payload length: 141) fe80::9ecc:83ff:fec6:e7e5.dhcpv6-server > vuurmuur.dhcpv6-client: [udp sum ok] dhcp6 advertise (xid=99c6e1 (client-ID hwaddr/time type 1 time 394565497 004063f60200) (server-ID vid 0000058339633a63) (IA_PD IAID:0 T1:3600 T2:5760 (IA_PD-prefix 2001:981:a812::/48 pltime:7200 vltime:7200)) (DNS-server 2001:888:0:6::66 resolver.xs4all.nl)) 12:40:01.305491 IP6 (flowlabel 0x0133d, hlim 1, next-header UDP (17) payload length: 60) vuurmuur.dhcpv6-client > ff02::1:2.dhcpv6-server: [udp sum ok] dhcp6 solicit (xid=99c6e1 (client-ID hwaddr/time type 1 time 394565497 004063f60200) (option-request DNS-server DNS-search-list) (elapsed-time 6517) (IA_PD IAID:0 T1:3600 T2:5400)) 12:40:01.320604 IP6 (class 0xc0, hlim 64, next-header UDP (17) payload length: 141) fe80::9ecc:83ff:fec6:e7e5.dhcpv6-server > vuurmuur.dhcpv6-client: [udp sum ok] dhcp6 advertise (xid=99c6e1 (client-ID hwaddr/time type 1 time 394565497 004063f60200) (server-ID vid 0000058339633a63) (IA_PD IAID:0 T1:3600 T2:5760 (IA_PD-prefix 2001:981:a812::/48 pltime:7200 vltime:7200)) (DNS-server 2001:888:0:6::66 resolver.xs4all.nl)) ^C 4 packets captured # The ipv6 firwall was emptied beforehand: # ip6tables -L -v -n -x Chain INPUT (policy DROP 211 packets, 57041 bytes) pkts bytes target prot opt in out source destination Chain FORWARD (policy DROP 97 packets, 8216 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 244 packets, 43209 bytes) pkts bytes target prot opt in out source destination Chain BLOCK (0 references) pkts bytes target prot opt in out source destination Chain CHECK (0 references) pkts bytes target prot opt in out source destination Chain LDROP (0 references) pkts bytes target prot opt in out source destination Chain LOG-FORWARD (0 references) pkts bytes target prot opt in out source destination Chain LOG-INPUT (0 references) pkts bytes target prot opt in out source destination Chain LOG-OUTPUT (0 references) pkts bytes target prot opt in out source destination So waht is to be fixed here? I was playing around with the IPv6 side of the ethernet interface that is the connection to the vdsl modem, and thus carries the PPPoE connection, etc. I removed IPv6 from the ethernet interface and also from the vlan interface over this ethernet. At this point ppp0 still has IPv6 link address. After restarting pppd etc the box received dhcp responses again. No, the change for the good did not persist.
Currently we see no dhcp-server replies processed by dhclient.
I do not understand why it worked and now why it stopped working.
UDP packet with dhcp-server reply comes in, is going to FORWARD ip6tables rule and then does not reach dhclient.
As dhclient is local, why does the UDP go to the FORWARD ip6tables rule?
We have a ppp interface:
# ip -6 a s dev ppp0
20: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1492 qdisc cbq state UNKNOWN group default qlen 3
inet6 fe80::c5d5:e942:39c7:7eb7 peer fe80::9ecc:83ff:fec6:e7e5/128 scope link
valid_lft forever preferred_lft forever
We have dhclient listening at ppp0:
# lsof -p 4066992 -n
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
dhclient 4066992 root cwd DIR 254,0 4096 40961 /root
dhclient 4066992 root rtd DIR 254,0 4096 2 /
dhclient 4066992 root txt REG 254,2 2018144 141553 /usr/sbin/dhclient
dhclient 4066992 root mem REG 254,2 53728 22104 /usr/lib64/libnss_files-2.33.so
dhclient 4066992 root mem REG 254,2 1913544 21939 /usr/lib64/libc-2.33.so
dhclient 4066992 root mem REG 254,2 32696 30196 /usr/lib64/libcap-ng.so.0.0.0
dhclient 4066992 root mem REG 254,2 842360 30776 /usr/lib64/ld-2.33.so
dhclient 4066992 root 0u CHR 136,4 0t0 7 /dev/pts/4 (deleted)
dhclient 4066992 root 1u CHR 136,4 0t0 7 /dev/pts/4 (deleted)
dhclient 4066992 root 2u CHR 136,4 0t0 7 /dev/pts/4 (deleted)
dhclient 4066992 root 3u unix 0x000000001f2593f7 0t0 16525445 type=DGRAM (UNCONNECTED)
dhclient 4066992 root 4w REG 254,4 64 251 /var/lib/dhclient/dhclient6.leases
dhclient 4066992 root 5w FIFO 0,8 0t0 16525446 pipe
dhclient 4066992 root 6u IPv6 16524541 0t0 UDP [fe80::c5d5:e942:39c7:7eb7]:dhcpv6-client
That appears to be all correct.
Then the packets that come in:
# tcpdump -i ppp0 -vn port 546
dropped privs to tcpdump
tcpdump: listening on ppp0, link-type LINUX_SLL (Linux cooked v1), snapshot length 262144 bytes
06:53:09.236781 IP6 (flowlabel 0x7f0d8, hlim 1, next-header UDP (17) payload length: 60) fe80::c5d5:e942:39c7:7eb7.dhcpv6-client > ff02::1:2.dhcpv6-server: [udp sum ok] dhcp6 solicit (xid=b68ba1 (client-ID hwaddr/time type 1 time 394565497 004063f60200) (option-request DNS-server DNS-search-list) (elapsed-time 65535) (IA_PD IAID:0 T1:3600 T2:5400))
06:53:09.469530 IP6 (class 0xc0, hlim 64, next-header UDP (17) payload length: 141) fe80::9ecc:83ff:fec6:e7e5.dhcpv6-server > fe80::c5d5:e942:39c7:7eb7.dhcpv6-client: [udp sum ok] dhcp6 advertise (xid=b68ba1 (client-ID hwaddr/time type 1 time 394565497 004063f60200) (server-ID vid 0000058339633a63) (IA_PD IAID:0 T1:3600 T2:5760 (IA_PD-prefix 2001:981:a812::/48 pltime:7200 vltime:7200)) (DNS-server 2001:888:0:6::66 2001:888:0:9::99))
06:53:09.469756 IP6 (class 0xc0, hlim 63, next-header UDP (17) payload length: 141) fe80::9ecc:83ff:fec6:e7e5.dhcpv6-server > fe80::c5d5:e942:39c7:7eb7.dhcpv6-client: [udp sum ok] dhcp6 advertise (xid=b68ba1 (client-ID hwaddr/time type 1 time 394565497 004063f60200) (server-ID vid 0000058339633a63) (IA_PD IAID:0 T1:3600 T2:5760 (IA_PD-prefix 2001:981:a812::/48 pltime:7200 vltime:7200)) (DNS-server 2001:888:0:6::66 2001:888:0:9::99))
^C
Appear to be addressed correctly, to the dhclient interface.
So why doesn't dhclient receive?
Things work well after a fresh reboot. But do not when pppd and thus dhclient are restarted. Even when firewall is off. This message is a reminder that Fedora Linux 34 is nearing its end of life. Fedora will stop maintaining and issuing updates for Fedora Linux 34 on 2022-06-07. It is Fedora's policy to close all bug reports from releases that are no longer maintained. At that time this bug will be closed as EOL if it remains open with a 'version' of '34'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, change the 'version' to a later Fedora Linux version. Thank you for reporting this issue and we are sorry that we were not able to fix it before Fedora Linux 34 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora Linux, you are encouraged to change the 'version' to a later version prior to this bug being closed. Fedora Linux 34 entered end-of-life (EOL) status on 2022-06-07. Fedora Linux 34 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. If you are unable to reopen this bug, please file a new report against the current release. Thank you for reporting this bug and we are sorry it could not be fixed. |