The RA's Retransmission Timer field was being ignored. This resolves the IPv6
Core Conformance test, v6LC.2.1.5 [1].
Retransmission Timer is a 32-bit unsigned integer. The time, in milliseconds,
between retransmitted Neighbor Solicitation messages. Used by the Address
Resolution and Neighbor Unreachability Detection (NUD) algorithm.
Support setting a default value for the neighbour retransmission timer value with:
[Network]
IPv6RetransmissionTimeSec=<int>
By default, upon receiving a Router Advertisement with the Retransmission Timer
field set to a non-zero value, it will update the kernel's retransmit timer value.
To disable this behaviour, configure the UseIPv6RetransmissionTime= under the
[IPv6AcceptRA] section.
[IPv6AcceptRA]
UseIPv6RetransmissionTime=<bool>
RFC4861: Neighbor Discovery in IPv6
* Section 4.2 RA Message Format.
* Section 6.3.4 Processing Received Router Advertisements
A Router Advertisement field (e.g., Cur Hop Limit, Reachable Time,
and Retrans Timer) may contain a value denoting that it is
unspecified. In such cases, the parameter should be ignored and the
host should continue using whatever value it is already using. In
particular, a host MUST NOT interpret the unspecified value as
meaning change back to the default value that was in use before the
first Router Advertisement was received.
The RetransTimer variable SHOULD be copied from the Retrans Timer
field, if the received value is non-zero.
References
[1] IPv6 Core Conformance Spec (PDF)
The data may be from user input or file. We usually use assertion for
programming error. Hence, using assert is not a good choise there.
Preparation for later commits.
Currently, networkd does not change pool size dynamically, so this
should not change behavior. But if networkd does that, then forgetting
leases causes that an address still used by a client may be assigned to
another host.
- Even if we found a matching static lease, check if there is no
conflicting lease.
- Accept an address request that is different from the previous one.
- Also return NAK if the server address is requested.
Several test cases intentionally trigger assert_return(). So, to avoid
the entire test fails, this introduces several macros that tentatively
make assert_return() not critical.
When assert_return() is critical, the following assertion is triggered
on exit:
---
#0 0x00007f8b1f6b0884 in __pthread_kill_implementation () from target:/lib64/libc.so.6
#1 0x00007f8b1f65fafe in raise () from target:/lib64/libc.so.6
#2 0x00007f8b1f64887f in abort () from target:/lib64/libc.so.6
#3 0x00007f8b208d02d6 in log_assert_failed (text=0x7f8b210009e0 "e->state != SD_EVENT_FINISHED", file=0x7f8b20fff403 "src/libsystemd/sd-event/sd-event.c",
line=1252, func=0x7f8b21004400 <__func__.154> "sd_event_add_io") at ../src/basic/log.c:948
#4 0x00007f8b208d0457 in log_assert_failed_return (text=0x7f8b210009e0 "e->state != SD_EVENT_FINISHED",
file=0x7f8b20fff403 "src/libsystemd/sd-event/sd-event.c", line=1252, func=0x7f8b21004400 <__func__.154> "sd_event_add_io") at ../src/basic/log.c:967
#5 0x00007f8b20c7d102 in sd_event_add_io (e=0x617000000080, ret=0x60c000000a20, fd=11, events=1, callback=0x7dfd85 <ipv4acd_on_packet>,
userdata=0x60c000000a00) at ../src/libsystemd/sd-event/sd-event.c:1252
#6 0x00000000007e3934 in sd_ipv4acd_start (acd=0x60c000000a00, reset_conflicts=true) at ../src/libsystemd-network/sd-ipv4acd.c:597
#7 0x00000000007e72b9 in ipv4ll_start_internal (ll=0x6080000006a0, reset_generation=true) at ../src/libsystemd-network/sd-ipv4ll.c:278
#8 0x00000000007e7462 in sd_ipv4ll_start (ll=0x6080000006a0) at ../src/libsystemd-network/sd-ipv4ll.c:298
#9 0x00000000006047a1 in dhcp4_handler (client=0x617000000400, event=0, userdata=0x61a000000680) at ../src/network/networkd-dhcp4.c:1183
#10 0x000000000075b1ed in client_notify (client=0x617000000400, event=0) at ../src/libsystemd-network/sd-dhcp-client.c:783
#11 0x000000000075bf8d in client_stop (client=0x617000000400, error=0) at ../src/libsystemd-network/sd-dhcp-client.c:821
#12 0x000000000077710f in sd_dhcp_client_stop (client=0x617000000400) at ../src/libsystemd-network/sd-dhcp-client.c:2388
#13 0x000000000065cdd1 in link_stop_engines (link=0x61a000000680, may_keep_dhcp=true) at ../src/network/networkd-link.c:336
#14 0x000000000041f214 in manager_free (m=0x618000000080) at ../src/network/networkd-manager.c:613
#15 0x00000000004124e3 in manager_freep (p=0x7f8b1c800040) at ../src/network/networkd-manager.h:128
#16 0x00000000004139f6 in run (argc=1, argv=0x7ffffe4522e8) at ../src/network/networkd.c:24
#17 0x0000000000413b20 in main (argc=1, argv=0x7ffffe4522e8) at ../src/network/networkd.c:119
---
Prompted by https://github.com/systemd/systemd/pull/30049#issuecomment-1844087965.
On architectures where timeval is 64bit but size_t is 32bit
we have to use CMSG_FIND_AND_COPY_DATA. This affects x32 and riscv32.
Follow-up for 905d0ea7b0
Those functions take a pointer to a timestamp and return a timestamp pointer,
so the reader would be justified to think that those are just getters. Rename
them to avoid confusion.
It seems that RFC does not say anything about the timestamp of lease
we should use: time that the client sent a request or received a reply.
In DHCPv6 client and NDisc, we use a timestamp that we receive a packet,
rather than we sent something. So, let's consistently use the same
logic for DHCPv4 client.
By using the logic, we will hopefully not forget to set timestamp again,
which is fixed by 089362976c.
Then, stop client in the caller side.
This also makes
- ignore all errors except for resource errors like OOM when FORCERENEW
is received,
- trigger assertion when an message received even if the client is
stopped.
This should not change any functionality. Just refactoring.
If a server replies an ACK for the initial DISCOVER, previously
request_sent was not set, so networkd handle the lease timed out.
Follow-up for 808b65a087.
This implements the DHCPv4 equivalent of the DHCPv6 Rapid Commit option,
enabling a lease to be selected in an accelerated 2-message exchange
instead of the typical 4-message exchange.
We use it for more than just pipe() arrays. For example also for
socketpair(). Hence let's give it a generic name.
Also add EBADF_TRIPLET to mirror this for things like
stdin/stdout/stderr arrays, which we use a bunch of times.
This is convenient when the server supports IPv6 only mode.
Otherwise, we cannot request a new address during the client is waiting an
IPv6 connectivity. Note, the minimal timespan is 5min, and a server may
send a quite large value.
