At various places we need to set a port on an IPv4 or IPv6 address, and
it requires casts that are easy to get wrong. Let's add a new set_port()
helper to the address family to assist in this. It will be directly
accessible from the protocol and will make the operation seamless.
Right now this is only implemented for sock_inet as other families do
not need a port.
We don't need to specify the handler anymore since it's set in the
receiver. Let's remove this argument from the function and clean up
the remains of code that were still setting it.
I was careful to have it for sock_unix.c but missed it for sock_inet
which broke with commit 36722d227 ("MINOR: sock_inet: report the errno
string in binding errors") depending on the build options. No backport
is needed.
With the socket binding code cleanup it becomes easy to add more info to
error messages. One missing thing used to be the error string, which is
now added after the generic one, for example:
[ALERT] 260/082852 (12974) : Starting frontend f: cannot bind socket (Permission denied) [0.0.0.0:4]
[ALERT] 260/083053 (13292) : Starting frontend f: cannot bind socket (Address already in use) [0.0.0.0:4444]
[ALERT] 260/083104 (13298) : Starting frontend f: cannot bind socket (Cannot assign requested address) [1.1.1.1:4444]
We now take care of retrieving sock_family, l3_addrlen, bind(),
addrcmp(), get_src() and get_dst() from the protocol family and
not just the protocol itself. There are very few places, this was
only seldom used. Interestingly in sock_inet.c used to rely on
->sock_family instead of ->sock_domain, and sock_unix.c used to
hard-code PF_UNIX instead of using ->sock_domain.
Also it appears obvious we have something wrong it the protocol
selection algorithm because sock_domain is the one set to the custom
protocols while it ought to be sock_family instead, which would avoid
having to hard-code some conversions for UDP namely.
We need to specially handle protocol families which regroup common
functions used for a given address family. These functions include
bind(), addrcmp(), get_src() and get_dst() for now. Some fields are
also added about the address family, socket domain (protocol family
passed to the socket() syscall), and address length.
These protocol families are referenced from the protocols but not yet
used.
This function collects all the receiver-specific code from both
tcp_bind_listener() and udp_bind_listener() in order to provide a more
generic AF_INET/AF_INET6 socket binding function. For now the API is
not very elegant because some info are still missing from the receiver
while there's no ideal place to fill them except when calling ->listen()
at the protocol level. It looks like some polishing code is needed in
check_config_validity() or somewhere around this in order to finalize
the receivers' setup. The main issue is that listeners and receivers
are created *before* bind_conf options are parsed and that there's no
finishing step to resolve some of them.
The function currently sets up a receiver and subscribes it to the
poller. In an ideal world we wouldn't subscribe it but let the caller
do it after having finished to configure the L4 stuff. The problem is
that the caller would then need to perform an fd_insert() call and to
possibly set the exported flag on the FD while it's not its job. Maybe
an improvement could be to have a separate sock_start_receiver() call
in sock.c.
For now the function is not used but it will soon be. It's already
referenced as tcp and udp's ->bind().
The new RX_O_FOREIGN, RX_O_V6ONLY and RX_O_V4V6 options are now set into
the rx_settings part during the parsing, so that we don't need to adjust
them in each and every listener anymore. We have to keep both v4v6 and
v6only due to the precedence from v6only over v4v6.
This code was highly redundant, existing for TCP clients, TCP servers
and UDP servers. Let's move it to sock_inet where it belongs. The new
functions are sock_inet4_make_foreign() and sock_inet6_make_foreign().
Let's determine it at boot time instead of doing it on first use. It
also saves us from having to keep it thread local. It's been moved to
the new sock_inet_prepare() function, and the variables were renamed
to sock_inet_tcp_maxseg_default and sock_inet6_tcp_maxseg_default.
The v6only_default variable is not specific to TCP but to AF_INET6, so
let's move it to the right file. It's now immediately filled on startup
during the PREPARE stage so that it doesn't have to be tested each time.
The variable's name was changed to sock_inet6_v6only_default.
The function now makes it clear that it's independent on the socket
type and solely relies on the address family. Note that it supports
both IPv4 and IPv6 as we don't seem to need it per-family.
This one is common to the TCPv4 and UDPv4 code, it retrieves the
destination address of a socket, taking care of the possiblity that for
an incoming connection the traffic was possibly redirected. The TCP and
UDP definitions were updated to rely on it and remove duplicated code.
These files will regroup everything specific to AF_INET, AF_INET6 and
AF_UNIX socket definitions and address management. Some code there might
be agnostic to the socket type and could later move to af_xxxx.c but for
now we only support regular sockets so no need to go too far.
The files are quite poor at this step, they only contain the address
comparison function for each address family.
