cat will always print "cat: test_network_log: Is a directory". change it to
head -n -0, which is arguably not the perfect format but is at least somewhat
useful.

Apparently glibc-2.34 uses clone3, when previously it just used
clone.

Closes ticket #40590.

We had 3 callsites setting up the circuit congestion control and so this
commit consolidates all 3 calls into 1 function.

Related to #40586

Signed-off-by: David Goulet <dgoulet@torproject.org>

Once the cpath is finalized, e2e encryption setup, transfer the ccontrol
from the rendezvous circuit to the cpath.

This allows the congestion control subsystem to properly function for
both upload and download side of onion services.

Closes #40586

Signed-off-by: David Goulet <dgoulet@torproject.org>

Fixes #40587

Signed-off-by: David Goulet <dgoulet@torproject.org>

Related #40312

Signed-off-by: David Goulet <dgoulet@torproject.org>

This applies only for relays. Previous commit adds two new consensus
parameters that dictate how libevent is configured with DNS resolution.
And so, with a new consensus, we now look at those values in case they
ever change.

Without this, Exit relay would have to HUP or restart to apply any new
Exit DNS consensus parameters.

Related to #40312

Signed-off-by: David Goulet <dgoulet@torproject.org>

Introduces two new consensus parameter:

  exit_dns_timeout: Number of seconds before libevent should consider
  the DNS request a timeout.

  exit_dns_num_attempts: Number of attempts that libeven should retry a
  previously failing query before calling it a timeout.

Closes #40312

Signed-off-by: David Goulet <dgoulet@torproject.org>

Closes #40520

Signed-off-by: David Goulet <dgoulet@torproject.org>

Signed-off-by: David Goulet <dgoulet@torproject.org>

Part of #40560

Signed-off-by: David Goulet <dgoulet@torproject.org>

This code was heavily reused from the previous DNS timeout work done in
ticket #40491 that was removed afterall from our code.

Closes #40560

Signed-off-by: David Goulet <dgoulet@torproject.org>

Fixes #40577

Signed-off-by: David Goulet <dgoulet@torproject.org>

Due to a possible Guard subsystem recursion, when the HS client gets
notified that the directory information has changed, it must run it in a
seperate mainloop event to avoid such issue.

See the ticket for more information on the recursion. This also fixes a
fatal assert.

Fixes #40579

Signed-off-by: David Goulet <dgoulet@torproject.org>

Signed-off-by: David Goulet <dgoulet@torproject.org>

It is possible to not have the descriptor anymore by the time the
rendezvous circuit opens. Don't BUG() on that.

Instead, when sending the INTRODUCE1 cell, make sure the descriptor we
have (or have just fetched) matches what we setup in the rendezvous
circuit.

If not, the circuit is closed and another one is opened for a retry.

Fixes #40576

Signed-off-by: David Goulet <dgoulet@torproject.org>