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libvirt/src/util/iptables.c
Eric Blake 36d8e7d8d7 build: consistently indent preprocessor directives 
* global: patch created by running:
for f in $(git ls-files '*.[ch]') ; do
    cppi $f > $f.t && mv $f.t $f
done
2010-03-09 19:22:28 +01:00

756 lines
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C
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/*
* Copyright (C) 2007-2009 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Authors:
* Mark McLoughlin <markmc@redhat.com>
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_SYS_WAIT_H
# include <sys/wait.h>
#endif
#ifdef HAVE_PATHS_H
# include <paths.h>
#endif
#include "internal.h"
#include "iptables.h"
#include "util.h"
#include "memory.h"
#include "virterror_internal.h"
#include "logging.h"
enum {
ADD = 0,
REMOVE
};
typedef struct
{
char *table;
char *chain;
} iptRules;
struct _iptablesContext
{
iptRules *input_filter;
iptRules *forward_filter;
iptRules *nat_postrouting;
};
static void
iptRulesFree(iptRules *rules)
{
VIR_FREE(rules->table);
VIR_FREE(rules->chain);
VIR_FREE(rules);
}
static iptRules *
iptRulesNew(const char *table,
const char *chain)
{
iptRules *rules;
if (VIR_ALLOC(rules) < 0)
return NULL;
if (!(rules->table = strdup(table)))
goto error;
if (!(rules->chain = strdup(chain)))
goto error;
return rules;
error:
iptRulesFree(rules);
return NULL;
}
static int ATTRIBUTE_SENTINEL
iptablesAddRemoveRule(iptRules *rules, int action, const char *arg, ...)
{
va_list args;
int retval = ENOMEM;
const char **argv;
const char *s;
int n;
n = 1 + /* /sbin/iptables */
2 + /* --table foo */
2 + /* --insert bar */
1; /* arg */
va_start(args, arg);
while (va_arg(args, const char *))
n++;
va_end(args);
if (VIR_ALLOC_N(argv, n + 1) < 0)
goto error;
n = 0;
if (!(argv[n++] = strdup(IPTABLES_PATH)))
goto error;
if (!(argv[n++] = strdup("--table")))
goto error;
if (!(argv[n++] = strdup(rules->table)))
goto error;
if (!(argv[n++] = strdup(action == ADD ? "--insert" : "--delete")))
goto error;
if (!(argv[n++] = strdup(rules->chain)))
goto error;
if (!(argv[n++] = strdup(arg)))
goto error;
va_start(args, arg);
while ((s = va_arg(args, const char *)))
if (!(argv[n++] = strdup(s)))
goto error;
va_end(args);
if (virRun(argv, NULL) < 0) {
retval = errno;
goto error;
}
retval = 0;
error:
if (argv) {
n = 0;
while (argv[n])
VIR_FREE(argv[n++]);
VIR_FREE(argv);
}
return retval;
}
/**
* iptablesContextNew:
*
* Create a new IPtable context
*
* Returns a pointer to the new structure or NULL in case of error
*/
iptablesContext *
iptablesContextNew(void)
{
iptablesContext *ctx;
if (VIR_ALLOC(ctx) < 0)
return NULL;
if (!(ctx->input_filter = iptRulesNew("filter", "INPUT")))
goto error;
if (!(ctx->forward_filter = iptRulesNew("filter", "FORWARD")))
goto error;
if (!(ctx->nat_postrouting = iptRulesNew("nat", "POSTROUTING")))
goto error;
return ctx;
error:
iptablesContextFree(ctx);
return NULL;
}
/**
* iptablesContextFree:
* @ctx: pointer to the IP table context
*
* Free the resources associated with an IP table context
*/
void
iptablesContextFree(iptablesContext *ctx)
{
if (ctx->input_filter)
iptRulesFree(ctx->input_filter);
if (ctx->forward_filter)
iptRulesFree(ctx->forward_filter);
if (ctx->nat_postrouting)
iptRulesFree(ctx->nat_postrouting);
VIR_FREE(ctx);
}
static int
iptablesInput(iptablesContext *ctx,
const char *iface,
int port,
int action,
int tcp)
{
char portstr[32];
snprintf(portstr, sizeof(portstr), "%d", port);
portstr[sizeof(portstr) - 1] = '\0';
return iptablesAddRemoveRule(ctx->input_filter,
action,
"--in-interface", iface,
"--protocol", tcp ? "tcp" : "udp",
"--destination-port", portstr,
"--jump", "ACCEPT",
NULL);
}
/**
* iptablesAddTcpInput:
* @ctx: pointer to the IP table context
* @iface: the interface name
* @port: the TCP port to add
*
* Add an input to the IP table allowing access to the given @port on
* the given @iface interface for TCP packets
*
* Returns 0 in case of success or an error code in case of error
*/
int
iptablesAddTcpInput(iptablesContext *ctx,
const char *iface,
int port)
{
return iptablesInput(ctx, iface, port, ADD, 1);
}
/**
* iptablesRemoveTcpInput:
* @ctx: pointer to the IP table context
* @iface: the interface name
* @port: the TCP port to remove
*
* Removes an input from the IP table, hence forbidding access to the given
* @port on the given @iface interface for TCP packets
*
* Returns 0 in case of success or an error code in case of error
*/
int
iptablesRemoveTcpInput(iptablesContext *ctx,
const char *iface,
int port)
{
return iptablesInput(ctx, iface, port, REMOVE, 1);
}
/**
* iptablesAddUdpInput:
* @ctx: pointer to the IP table context
* @iface: the interface name
* @port: the UDP port to add
*
* Add an input to the IP table allowing access to the given @port on
* the given @iface interface for UDP packets
*
* Returns 0 in case of success or an error code in case of error
*/
int
iptablesAddUdpInput(iptablesContext *ctx,
const char *iface,
int port)
{
return iptablesInput(ctx, iface, port, ADD, 0);
}
/**
* iptablesRemoveUdpInput:
* @ctx: pointer to the IP table context
* @iface: the interface name
* @port: the UDP port to remove
*
* Removes an input from the IP table, hence forbidding access to the given
* @port on the given @iface interface for UDP packets
*
* Returns 0 in case of success or an error code in case of error
*/
int
iptablesRemoveUdpInput(iptablesContext *ctx,
const char *iface,
int port)
{
return iptablesInput(ctx, iface, port, REMOVE, 0);
}
/* Allow all traffic coming from the bridge, with a valid network address
* to proceed to WAN
*/
static int
iptablesForwardAllowOut(iptablesContext *ctx,
const char *network,
const char *iface,
const char *physdev,
int action)
{
if (physdev && physdev[0]) {
return iptablesAddRemoveRule(ctx->forward_filter,
action,
"--source", network,
"--in-interface", iface,
"--out-interface", physdev,
"--jump", "ACCEPT",
NULL);
} else {
return iptablesAddRemoveRule(ctx->forward_filter,
action,
"--source", network,
"--in-interface", iface,
"--jump", "ACCEPT",
NULL);
}
}
/**
* iptablesAddForwardAllowOut:
* @ctx: pointer to the IP table context
* @network: the source network name
* @iface: the source interface name
* @physdev: the physical output device
*
* Add a rule to the IP table context to allow the traffic for the
* network @network via interface @iface to be forwarded to
* @physdev device. This allow the outbound traffic on a bridge.
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesAddForwardAllowOut(iptablesContext *ctx,
const char *network,
const char *iface,
const char *physdev)
{
return iptablesForwardAllowOut(ctx, network, iface, physdev, ADD);
}
/**
* iptablesRemoveForwardAllowOut:
* @ctx: pointer to the IP table context
* @network: the source network name
* @iface: the source interface name
* @physdev: the physical output device
*
* Remove a rule from the IP table context hence forbidding forwarding
* of the traffic for the network @network via interface @iface
* to the @physdev device output. This stops the outbound traffic on a bridge.
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesRemoveForwardAllowOut(iptablesContext *ctx,
const char *network,
const char *iface,
const char *physdev)
{
return iptablesForwardAllowOut(ctx, network, iface, physdev, REMOVE);
}
/* Allow all traffic destined to the bridge, with a valid network address
* and associated with an existing connection
*/
static int
iptablesForwardAllowRelatedIn(iptablesContext *ctx,
const char *network,
const char *iface,
const char *physdev,
int action)
{
if (physdev && physdev[0]) {
return iptablesAddRemoveRule(ctx->forward_filter,
action,
"--destination", network,
"--in-interface", physdev,
"--out-interface", iface,
"--match", "state",
"--state", "ESTABLISHED,RELATED",
"--jump", "ACCEPT",
NULL);
} else {
return iptablesAddRemoveRule(ctx->forward_filter,
action,
"--destination", network,
"--out-interface", iface,
"--match", "state",
"--state", "ESTABLISHED,RELATED",
"--jump", "ACCEPT",
NULL);
}
}
/**
* iptablesAddForwardAllowRelatedIn:
* @ctx: pointer to the IP table context
* @network: the source network name
* @iface: the output interface name
* @physdev: the physical input device or NULL
*
* Add rules to the IP table context to allow the traffic for the
* network @network on @physdev device to be forwarded to
* interface @iface, if it is part of an existing connection.
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesAddForwardAllowRelatedIn(iptablesContext *ctx,
const char *network,
const char *iface,
const char *physdev)
{
return iptablesForwardAllowRelatedIn(ctx, network, iface, physdev, ADD);
}
/**
* iptablesRemoveForwardAllowRelatedIn:
* @ctx: pointer to the IP table context
* @network: the source network name
* @iface: the output interface name
* @physdev: the physical input device or NULL
*
* Remove rules from the IP table context hence forbidding the traffic for
* network @network on @physdev device to be forwarded to
* interface @iface, if it is part of an existing connection.
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesRemoveForwardAllowRelatedIn(iptablesContext *ctx,
const char *network,
const char *iface,
const char *physdev)
{
return iptablesForwardAllowRelatedIn(ctx, network, iface, physdev, REMOVE);
}
/* Allow all traffic destined to the bridge, with a valid network address
*/
static int
iptablesForwardAllowIn(iptablesContext *ctx,
const char *network,
const char *iface,
const char *physdev,
int action)
{
if (physdev && physdev[0]) {
return iptablesAddRemoveRule(ctx->forward_filter,
action,
"--destination", network,
"--in-interface", physdev,
"--out-interface", iface,
"--jump", "ACCEPT",
NULL);
} else {
return iptablesAddRemoveRule(ctx->forward_filter,
action,
"--destination", network,
"--out-interface", iface,
"--jump", "ACCEPT",
NULL);
}
}
/**
* iptablesAddForwardAllowIn:
* @ctx: pointer to the IP table context
* @network: the source network name
* @iface: the output interface name
* @physdev: the physical input device or NULL
*
* Add rules to the IP table context to allow the traffic for the
* network @network on @physdev device to be forwarded to
* interface @iface. This allow the inbound traffic on a bridge.
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesAddForwardAllowIn(iptablesContext *ctx,
const char *network,
const char *iface,
const char *physdev)
{
return iptablesForwardAllowIn(ctx, network, iface, physdev, ADD);
}
/**
* iptablesRemoveForwardAllowIn:
* @ctx: pointer to the IP table context
* @network: the source network name
* @iface: the output interface name
* @physdev: the physical input device or NULL
*
* Remove rules from the IP table context hence forbidding the traffic for
* network @network on @physdev device to be forwarded to
* interface @iface. This stops the inbound traffic on a bridge.
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesRemoveForwardAllowIn(iptablesContext *ctx,
const char *network,
const char *iface,
const char *physdev)
{
return iptablesForwardAllowIn(ctx, network, iface, physdev, REMOVE);
}
/* Allow all traffic between guests on the same bridge,
* with a valid network address
*/
static int
iptablesForwardAllowCross(iptablesContext *ctx,
const char *iface,
int action)
{
return iptablesAddRemoveRule(ctx->forward_filter,
action,
"--in-interface", iface,
"--out-interface", iface,
"--jump", "ACCEPT",
NULL);
}
/**
* iptablesAddForwardAllowCross:
* @ctx: pointer to the IP table context
* @iface: the input/output interface name
*
* Add rules to the IP table context to allow traffic to cross that
* interface. It allows all traffic between guests on the same bridge
* represented by that interface.
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesAddForwardAllowCross(iptablesContext *ctx,
const char *iface) {
return iptablesForwardAllowCross(ctx, iface, ADD);
}
/**
* iptablesRemoveForwardAllowCross:
* @ctx: pointer to the IP table context
* @iface: the input/output interface name
*
* Remove rules to the IP table context to block traffic to cross that
* interface. It forbids traffic between guests on the same bridge
* represented by that interface.
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesRemoveForwardAllowCross(iptablesContext *ctx,
const char *iface) {
return iptablesForwardAllowCross(ctx, iface, REMOVE);
}
/* Drop all traffic trying to forward from the bridge.
* ie the bridge is the in interface
*/
static int
iptablesForwardRejectOut(iptablesContext *ctx,
const char *iface,
int action)
{
return iptablesAddRemoveRule(ctx->forward_filter,
action,
"--in-interface", iface,
"--jump", "REJECT",
NULL);
}
/**
* iptablesAddForwardRejectOut:
* @ctx: pointer to the IP table context
* @iface: the output interface name
*
* Add rules to the IP table context to forbid all traffic to that
* interface. It forbids forwarding from the bridge to that interface.
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesAddForwardRejectOut(iptablesContext *ctx,
const char *iface)
{
return iptablesForwardRejectOut(ctx, iface, ADD);
}
/**
* iptablesRemoveForwardRejectOut:
* @ctx: pointer to the IP table context
* @iface: the output interface name
*
* Remove rules from the IP table context forbidding all traffic to that
* interface. It reallow forwarding from the bridge to that interface.
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesRemoveForwardRejectOut(iptablesContext *ctx,
const char *iface)
{
return iptablesForwardRejectOut(ctx, iface, REMOVE);
}
/* Drop all traffic trying to forward to the bridge.
* ie the bridge is the out interface
*/
static int
iptablesForwardRejectIn(iptablesContext *ctx,
const char *iface,
int action)
{
return iptablesAddRemoveRule(ctx->forward_filter,
action,
"--out-interface", iface,
"--jump", "REJECT",
NULL);
}
/**
* iptablesAddForwardRejectIn:
* @ctx: pointer to the IP table context
* @iface: the input interface name
*
* Add rules to the IP table context to forbid all traffic from that
* interface. It forbids forwarding from that interface to the bridge.
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesAddForwardRejectIn(iptablesContext *ctx,
const char *iface)
{
return iptablesForwardRejectIn(ctx, iface, ADD);
}
/**
* iptablesRemoveForwardRejectIn:
* @ctx: pointer to the IP table context
* @iface: the input interface name
*
* Remove rules from the IP table context forbidding all traffic from that
* interface. It allows forwarding from that interface to the bridge.
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesRemoveForwardRejectIn(iptablesContext *ctx,
const char *iface)
{
return iptablesForwardRejectIn(ctx, iface, REMOVE);
}
/* Masquerade all traffic coming from the network associated
* with the bridge
*/
static int
iptablesForwardMasquerade(iptablesContext *ctx,
const char *network,
const char *physdev,
int action)
{
if (physdev && physdev[0]) {
return iptablesAddRemoveRule(ctx->nat_postrouting,
action,
"--source", network,
"!", "--destination", network,
"--out-interface", physdev,
"--jump", "MASQUERADE",
NULL);
} else {
return iptablesAddRemoveRule(ctx->nat_postrouting,
action,
"--source", network,
"!", "--destination", network,
"--jump", "MASQUERADE",
NULL);
}
}
/**
* iptablesAddForwardMasquerade:
* @ctx: pointer to the IP table context
* @network: the source network name
* @physdev: the physical input device or NULL
*
* Add rules to the IP table context to allow masquerading
* network @network on @physdev. This allow the bridge to
* masquerade for that network (on @physdev).
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesAddForwardMasquerade(iptablesContext *ctx,
const char *network,
const char *physdev)
{
return iptablesForwardMasquerade(ctx, network, physdev, ADD);
}
/**
* iptablesRemoveForwardMasquerade:
* @ctx: pointer to the IP table context
* @network: the source network name
* @physdev: the physical input device or NULL
*
* Remove rules from the IP table context to stop masquerading
* network @network on @physdev. This stops the bridge from
* masquerading for that network (on @physdev).
*
* Returns 0 in case of success or an error code otherwise
*/
int
iptablesRemoveForwardMasquerade(iptablesContext *ctx,
const char *network,
const char *physdev)
{
return iptablesForwardMasquerade(ctx, network, physdev, REMOVE);
}
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