[Nbd] [PATCH] nbd-server: Limit the number of connections
- To: nbd-general@lists.sourceforge.net
- Subject: [Nbd] [PATCH] nbd-server: Limit the number of connections
- From: Gregory Thiemonge <greg@...836...>
- Date: Mon, 27 Sep 2010 16:04:36 +0200
- Message-id: <20100927140435.GD18340@...836...>
Hi there,
This is a patch that allows to limit the number of opened connections in
nbd-server.
This limitation can be specified from both command line and config
files:
- -M <n> or --max-connections <n> from command line
- or maxconnections = <n> in config files (export sections)
Regards,
Greg
---
man/nbd-server.1.in.sgml | 8 ++++++++
man/nbd-server.5.in.sgml | 10 ++++++++++
nbd-server.c | 22 +++++++++++++++++++---
3 files changed, 37 insertions(+), 3 deletions(-)
diff --git a/man/nbd-server.1.in.sgml b/man/nbd-server.1.in.sgml
index c9190b0..7b7f185 100644
--- a/man/nbd-server.1.in.sgml
+++ b/man/nbd-server.1.in.sgml
@@ -66,6 +66,7 @@ manpage.1: manpage.sgml
<arg><option>-l <replaceable>host list filename</replaceable></option></arg>
<arg><option>-o <replaceable>section name</replaceable></option></arg>
<arg><option>-C <replaceable>config file</replaceable></option></arg>
+ <arg><option>-M <replaceable>max connections</replaceable></option></arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
@@ -208,6 +209,13 @@ manpage.1: manpage.sgml
</listitem>
</varlistentry>
<varlistentry>
+ <term><option>-M</option></term>
+ <listitem>
+ <para>Specify the maximum number of opened connections. If this
+ parameter is not specified, no limit is set.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
<term><option>host list filename</option></term>
<listitem>
<para>This argument should contain a list of IP-addresses
diff --git a/man/nbd-server.5.in.sgml b/man/nbd-server.5.in.sgml
index f0aae0a..351fd80 100644
--- a/man/nbd-server.5.in.sgml
+++ b/man/nbd-server.5.in.sgml
@@ -596,6 +596,16 @@ manpage.1: manpage.sgml
</para>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>maxconnections</option></term>
+ <listitem>
+ <para>Optional; integer</para>
+ <para>
+ If specified, then it limits the number of opened connections for
+ this export.
+ </para>
+ </listitem>
+ </varlistentry>
</variablelist>
</refsect1>
diff --git a/nbd-server.c b/nbd-server.c
index a11e37a..820458c 100644
--- a/nbd-server.c
+++ b/nbd-server.c
@@ -204,6 +204,7 @@ typedef struct {
gchar* postrun; /**< command that will be ran after the client
disconnects */
gchar* servename; /**< name of the export as selected by nbd-client */
+ int max_connections; /**< maximum number of opened connections */
} SERVER;
/**
@@ -358,14 +359,15 @@ inline void writeit(int f, void *buf, size_t len) {
*/
void usage() {
printf("This is nbd-server version " VERSION "\n");
- printf("Usage: [ip:|ip6@]port file_to_export [size][kKmM] [-l authorize_file] [-r] [-m] [-c] [-C configuration file] [-p PID file name] [-o section name]\n"
+ printf("Usage: [ip:|ip6@]port file_to_export [size][kKmM] [-l authorize_file] [-r] [-m] [-c] [-C configuration file] [-p PID file name] [-o section name] [-M max connections]\n"
"\t-r|--read-only\t\tread only\n"
"\t-m|--multi-file\t\tmultiple file\n"
"\t-c|--copy-on-write\tcopy on write\n"
"\t-C|--config-file\tspecify an alternate configuration file\n"
"\t-l|--authorize-file\tfile with list of hosts that are allowed to\n\t\t\t\tconnect.\n"
"\t-p|--pid-file\t\tspecify a filename to write our PID to\n"
- "\t-o|--output-config\toutput a config file section for what you\n\t\t\t\tspecified on the command line, with the\n\t\t\t\tspecified section name\n\n"
+ "\t-o|--output-config\toutput a config file section for what you\n\t\t\t\tspecified on the command line, with the\n\t\t\t\tspecified section name\n"
+ "\t-M|--max-connections\tspecify the maximum number of opened connections\n\n"
"\tif port is set to 0, stdin is used (for running from inetd)\n"
"\tif file_to_export contains '%%s', it is substituted with the IP\n"
"\t\taddress of the machine trying to connect\n"
@@ -415,6 +417,7 @@ SERVER* cmdline(int argc, char *argv[]) {
{"config-file", required_argument, NULL, 'C'},
{"pid-file", required_argument, NULL, 'p'},
{"output-config", required_argument, NULL, 'o'},
+ {"max-connection", required_argument, NULL, 'M'},
{0,0,0,0}
};
SERVER *serve;
@@ -431,7 +434,7 @@ SERVER* cmdline(int argc, char *argv[]) {
serve=g_new0(SERVER, 1);
serve->authname = g_strdup(default_authname);
serve->virtstyle=VIRT_IPLIT;
- while((c=getopt_long(argc, argv, "-C:cl:mo:rp:", long_options, &i))>=0) {
+ while((c=getopt_long(argc, argv, "-C:cl:mo:rp:M:", long_options, &i))>=0) {
switch (c) {
case 1:
/* non-option argument */
@@ -508,6 +511,9 @@ SERVER* cmdline(int argc, char *argv[]) {
g_free(serve->authname);
serve->authname=g_strdup(optarg);
break;
+ case 'M':
+ serve->max_connections = strtol(optarg, NULL, 0);
+ break;
default:
usage();
exit(EXIT_FAILURE);
@@ -606,6 +612,8 @@ SERVER* dup_serve(SERVER *s) {
if(s->servename)
serve->servename = g_strdup(s->servename);
+ serve->max_connections = s->max_connections;
+
return serve;
}
@@ -705,6 +713,7 @@ GArray* parse_cfile(gchar* f, GError** e) {
{ "sdp", FALSE, PARAM_BOOL, NULL, F_SDP },
{ "sync", FALSE, PARAM_BOOL, NULL, F_SYNC },
{ "listenaddr", FALSE, PARAM_STRING, NULL, 0 },
+ { "maxconnections", FALSE, PARAM_INT, NULL, 0 },
};
const int lp_size=sizeof(lp)/sizeof(PARAM);
PARAM gp[] = {
@@ -755,6 +764,7 @@ GArray* parse_cfile(gchar* f, GError** e) {
lp[10].target=lp[11].target=
lp[12].target=&(s.flags);
lp[13].target=&(s.listenaddr);
+ lp[14].target=&(s.max_connections);
/* After the [generic] group, start parsing exports */
if(i==1) {
@@ -1739,6 +1749,12 @@ int serveloop(GArray* servers) {
if(net) {
int sock_flags;
+ if(serve->max_connections > 0 &&
+ g_hash_table_size(children) >= serve->max_connections) {
+ msg2(LOG_INFO, "Max connections reached");
+ close(net);
+ continue;
+ }
if((sock_flags = fcntl(net, F_GETFL, 0))==-1) {
err("fcntl F_GETFL");
}
--
1.7.1
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