Slirp uses rfds/wfds/xfds more extensively than other QEMU components.
The rarely-used out-of-band TCP data feature is used. That means we
need the full table of select(2) to g_poll(3) events:
rfds -> G_IO_IN | G_IO_HUP | G_IO_ERR
wfds -> G_IO_OUT | G_IO_ERR
xfds -> G_IO_PRI
I came up with this table by looking at Linux fs/select.c which maps
select(2) to poll(2) internally.
Another detail to watch out for are the global variables that reference
rfds/wfds/xfds during slirp_select_poll(). sofcantrcvmore() and
sofcantsendmore() use these globals to clear fd_set bits. When
sofcantrcvmore() is called, the wfds bit is cleared so that the write
handler will no longer be run for this iteration of the event loop.
This actually seems buggy to me since TCP connections can be half-closed
and we'd still want to handle data in half-duplex fashion. I think the
real intention is to avoid running the read/write handler when the
socket has been fully closed. This is indicated with the SS_NOFDREF
state bit so we now check for it before invoking the TCP write handler.
Note that UDP/ICMP code paths don't care because they are
connectionless.
Note that slirp/ has a lot of tabs and sometimes mixed tabs with spaces.
I followed the style of the surrounding code.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1361356113-11049-6-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
in_addr_t isn't available on mingw32. Just use an unsigned long instead. I
considered typedef'ing in_addr_t on mingw32 but this would potentially be
brittle if mingw32 did introduce the type.
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Changes so translation of remote address to the host's ip address in
the virtual network happens for all addresses in the 127.0.0.0/8
network, not just 127.0.0.1.
This fixes so that hostfwd bound to addresses such as 127.0.0.2 works.
Signed-off-by: Anders Waldenborg <anders@0x63.nu>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
In the current implementation, if Slirp tries to send an IP packet to a client
with an unknown hardware address, the packet is simply dropped and an ARP
request is sent (if_encap in slirp/slirp.c).
With this patch, Slirp will send the ARP request, re-queue the packet and try
to send it later. The packet is dropped after one second if the ARP reply is
not received.
Signed-off-by: Fabien Chouteau <chouteau@adacore.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
There is no need to have a second set of integral types.
Replace them by the standard types from stdint.h.
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Currently the qemu user-mode networking stack reads the host DNS
configuration (/etc/resolv.conf or the Windows equivalent) only once
when qemu starts. This causes name lookups in the guest to fail if the
host is moved to a different network from which the original DNS servers
are unreachable, a common occurrence when the host is a laptop.
This patch changes the slirp code to read the host DNS configuration on
demand, caching the results for at most 1 second to avoid unnecessary
overhead if name lookups occur in rapid succession. On non-Windows
hosts, /etc/resolv.conf is re-read only if the file has been replaced or
if its size or mtime has changed.
Signed-off-by: Ed Swierk <eswierk@aristanetworks.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Three problems with our_addr:
- It's determined only once when qemu starts, but the address can change
(just like the DNS configuration can).
- It's supposed to be the IP address of a host network interface, but
there's no guarantee that gethostbyname(gethostname()) actually does
that: the host might be a laptop that has only a loopback interface up,
or the hostname might be localhost.localdomain, etc.
- It's useless at best: get_dns_addr() calls it, there's no reason to
send DNS requests to a different IP address if you're running a DNS
server on the host and resolv.conf points to 127.0.0.1.
These problems are easily solved by removing the code.
Signed-off-by: Ed Swierk <eswierk@aristanetworks.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Allocate the internal slirp state dynamically and provide and call
slirp_cleanup to properly release it after use. This patch finally
unbreaks slirp release and re-instantiation via host_net_* monitor
commands.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The essence of this patch is to stuff (almost) all global variables of
the slirp stack into the structure Slirp. In this step, we still keep
the structure as global variable, directly accessible by the whole
stack. Changes to the external interface of slirp will be applied in
the following patches.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Drop redundant typecasts in both variants and remove the pointless
round-up in the UNIX version.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
With the internal IP configuration made more flexible, we can now
enhance the user interface. This patch adds a number of new options to
"-net user": net (address and mask), host, dhcpstart, dns and smbserver.
It also renames "redir" to "hostfwd" and "channel" to "guestfwd" in
order to (hopefully) clarify their meanings. The format of guestfwd is
extended so that the user can define not only the port but also the
virtual server's IP address the forwarding starts from.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The user mode IP stack is currently only minimally configurable /wrt to
its virtual IP addresses. This is unfortunate if some guest has a fixed
idea of which IP addresses to use.
Therefore this patch prepares the stack for fully configurable IP
addresses and masks. The user interface and default addresses remain
untouched in this step, they will be enhanced in the following patch.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
So far a couple of slirp-related parameters were expressed via
stand-alone command line options. This it inconsistent and unintuitive.
Moreover, it prevents both dynamically reconfigured (host_net_add/
delete) and multi-instance slirp.
This patch refactors the configuration by turning -smb, -redir, -tftp
and -bootp as well as -net channel into options of "-net user". The old
stand-alone command line options are still processed, but no longer
advertised. This allows smooth migration of management applications to
to the new syntax and also the extension of that syntax later in this
series.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
