From b412eb61bfd400ad70afe11ac3a5fb2931124804 Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Sun, 3 Jun 2012 09:45:01 +0200 Subject: [PATCH] slirp: add 'cmd:' target for guestfwd When using guestfwd=, Qemu only connects the virtual server's TCP port to a single chardev. This is useless in most cases, as we usually want to have more than a single connection from the guest to the outside world. This patch adds a new cmd: target to guestfwd= that allows for execution of a command on every TCP connection. This leverages the same code as the -smb parameter, just that here the command is user defined. Reported-by: Sascha Wilde Signed-off-by: Alexander Graf Signed-off-by: Jan Kiszka --- net/slirp.c | 44 +++++++++++++++++++++++++++----------------- qemu-options.hx | 22 +++++++++++++++++++++- 2 files changed, 48 insertions(+), 18 deletions(-) diff --git a/net/slirp.c b/net/slirp.c index a43b5764e1..180147e831 100644 --- a/net/slirp.c +++ b/net/slirp.c @@ -626,25 +626,35 @@ static int slirp_guestfwd(SlirpState *s, const char *config_str, fwd = g_malloc(sizeof(struct GuestFwd)); snprintf(buf, sizeof(buf), "guestfwd.tcp.%d", port); - fwd->hd = qemu_chr_new(buf, p, NULL); - if (!fwd->hd) { - error_report("could not open guest forwarding device '%s'", buf); - g_free(fwd); - return -1; - } - if (slirp_add_exec(s->slirp, 3, fwd->hd, &server, port) < 0) { - error_report("conflicting/invalid host:port in guest forwarding " - "rule '%s'", config_str); - g_free(fwd); - return -1; - } - fwd->server = server; - fwd->port = port; - fwd->slirp = s->slirp; + if ((strlen(p) > 4) && !strncmp(p, "cmd:", 4)) { + if (slirp_add_exec(s->slirp, 0, &p[4], &server, port) < 0) { + error_report("conflicting/invalid host:port in guest forwarding " + "rule '%s'", config_str); + g_free(fwd); + return -1; + } + } else { + fwd->hd = qemu_chr_new(buf, p, NULL); + if (!fwd->hd) { + error_report("could not open guest forwarding device '%s'", buf); + g_free(fwd); + return -1; + } - qemu_chr_add_handlers(fwd->hd, guestfwd_can_read, guestfwd_read, - NULL, fwd); + if (slirp_add_exec(s->slirp, 3, fwd->hd, &server, port) < 0) { + error_report("conflicting/invalid host:port in guest forwarding " + "rule '%s'", config_str); + g_free(fwd); + return -1; + } + fwd->server = server; + fwd->port = port; + fwd->slirp = s->slirp; + + qemu_chr_add_handlers(fwd->hd, guestfwd_can_read, guestfwd_read, + NULL, fwd); + } return 0; fail_syntax: diff --git a/qemu-options.hx b/qemu-options.hx index 8b662648ae..ecf7ca12d7 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -1421,8 +1421,28 @@ Then when you use on the host @code{telnet localhost 5555}, you connect to the guest telnet server. @item guestfwd=[tcp]:@var{server}:@var{port}-@var{dev} +@item guestfwd=[tcp]:@var{server}:@var{port}-@var{cmd:command} Forward guest TCP connections to the IP address @var{server} on port @var{port} -to the character device @var{dev}. This option can be given multiple times. +to the character device @var{dev} or to a program executed by @var{cmd:command} +which gets spawned for each connection. This option can be given multiple times. + +You can either use a chardev directly and have that one used throughout Qemu's +lifetime, like in the following example: + +@example +# open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever +# the guest accesses it +qemu -net user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 [...] +@end example + +Or you can execute a command on every TCP connection established by the guest, +so that Qemu behaves similar to an inetd process for that virtual server: + +@example +# call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 +# and connect the TCP stream to its stdin/stdout +qemu -net 'user,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' +@end example @end table