Resetting the interface just based on the fact that it already has an IP
assigned doesn't make much sense, considering that we frequently end up
here after having configured an interface via DHCP already.
Instead, just keep the part that prevents us from sending DHCP
discoveries to interfaces that shouldn't be using DHCP.
While we are at it, place some of the logging behind a debug flag, as
this function is apparently meant to be run frequently.
This partially reverts commit e14d4482a1.
Now, the caller needs to give interface names in command-line arguments.
The DHCPClient will perform DHCP discovery only on these adapters. The
service now immediately closes when no interfaces were given.
We don't check if interface has already IP address assigned; we just
reset it to zero so that DHCP resolution will not fail.
Also add slightly richer parse errors now that we can include a string
literal with returned errors.
This will allow us to use TRY() when working with JSON data.
Previously we'd only only send one DHCP request for network interfaces
which were up when DHCPClient started. If that packet was lost we'd
never send another request for those interfaces.
Also, if an interface were to appear after DHCPClient started (not
that that is possible at the moment) we wouldn't send requests for
that interface either.
We had some inconsistencies before:
- Sometimes "The", sometimes "the"
- Sometimes trailing ".", sometimes no trailing "."
I picked the most common one (lowecase "the", trailing ".") and applied
it to all copyright headers.
By using the exact same string everywhere we can ensure nothing gets
missed during a global search (and replace), and that these
inconsistencies are not spread any further (as copyright headers are
commonly copied to new files).
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
Attempts are spaced out with exponential backoff, cut at 10 minutes per
attempt.
Also avoid trying to acquire an IP on interfaces that aren't up.
Fixes#6126.
Fixes#6125.
Real DHCP servers might decide to send the DHCPAck directly to the
specified ciaddr instead of as a unicast or multicast, resulting in
the ack being ignored by the network adapter when we are requesting
a new IPv4 address instead of renewing an existing lease, as the
yiaddr (and as a result the ciaddr) is set to the offered address in
that case instead of the current ip address.
Some real DHCP servers dont set the siaddr field in the DHCPOffer to
their IPv4 (and instead leave it blank - 0.0.0.0), which results in
the server assuming the DHCPRequest is not directed at him when it
has the ServerIdentifier option attached that specifies 0.0.0.0 as
the targeted server. So instead we just omit the option and let the
DHCP servers decipher the target themselves based on the requested IP.
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
