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fwknop/server/fw_util_iptables.c
Michael Rash 9b7c1a8ce6 Added FORCE_NAT mode to the access.conf file 
This commit adds a new configuration variable "FORCE_NAT" to the access.conf
file:

    For any valid SPA packet, force the requested connection to be NAT'd
    through to the specified (usually internal) IP and port value.  This is
    useful if there are multiple internal systems running a service such as
    SSHD, and you want to give transparent access to only one internal system
    for each stanza in the access.conf file.  This way, multiple external
    users can each directly access only one internal system per SPA key.

This commit also implements a few minor code cleanups.
2011-11-30 20:51:19 -05:00

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/*
*****************************************************************************
*
* File: fw_util_iptables.c
*
* Author: Damien S. Stuart
*
* Purpose: Fwknop routines for managing iptables firewall rules.
*
* Copyright 2010 Damien Stuart (dstuart@dstuart.org)
*
* License (GNU Public License):
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*
*****************************************************************************
*/
#include "fwknopd_common.h"
#ifdef FIREWALL_IPTABLES
#include "fw_util.h"
#include "utils.h"
#include "log_msg.h"
#include "extcmd.h"
#include "access.h"
static struct fw_config fwc;
static char cmd_buf[CMD_BUFSIZE];
static char err_buf[CMD_BUFSIZE];
static char cmd_out[STANDARD_CMD_OUT_BUFSIZE];
static void
zero_cmd_buffers(void)
{
memset(cmd_buf, 0x0, CMD_BUFSIZE);
memset(err_buf, 0x0, CMD_BUFSIZE);
memset(cmd_out, 0x0, STANDARD_CMD_OUT_BUFSIZE);
}
static int
add_jump_rule(const fko_srv_options_t *opts, const int chain_num)
{
int res = 0;
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_ADD_JUMP_RULE_ARGS,
fwc.fw_command,
fwc.chain[chain_num].table,
fwc.chain[chain_num].from_chain,
fwc.chain[chain_num].jump_rule_pos,
fwc.chain[chain_num].to_chain
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, 0);
if (opts->verbose)
log_msg(LOG_INFO, "add_jump_rule() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res))
log_msg(LOG_INFO, "Added jump rule from chain: %s to chain: %s",
fwc.chain[chain_num].from_chain,
fwc.chain[chain_num].to_chain);
else
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
return res;
}
static int
jump_rule_exists(const int chain_num)
{
int num, pos = 0;
char cmd_buf[CMD_BUFSIZE] = {0};
char target[CMD_BUFSIZE] = {0};
char line_buf[CMD_BUFSIZE] = {0};
FILE *ipt;
sprintf(cmd_buf, "%s " IPT_LIST_RULES_ARGS,
fwc.fw_command,
fwc.chain[chain_num].table,
fwc.chain[chain_num].from_chain
);
ipt = popen(cmd_buf, "r");
if(ipt == NULL)
{
log_msg(LOG_ERR,
"Got error %i trying to get rules list.\n", errno);
return(-1);
}
while((fgets(line_buf, CMD_BUFSIZE-1, ipt)) != NULL)
{
/* Get past comments and empty lines (note: we only look at the
* first character).
*/
if(IS_EMPTY_LINE(line_buf[0]))
continue;
if(sscanf(line_buf, "%i %s ", &num, target) == 2)
{
if(strcmp(target, fwc.chain[chain_num].to_chain) == 0)
{
pos = num;
break;
}
}
}
pclose(ipt);
return(pos);
}
/* Print all firewall rules currently instantiated by the running fwknopd
* daemon to stdout.
*/
int
fw_dump_rules(const fko_srv_options_t *opts)
{
int i;
int res, got_err = 0;
struct fw_chain *ch = opts->fw_config->chain;
if (opts->fw_list_all == 1)
{
fprintf(stdout, "Listing all iptables rules in applicable tables...\n");
fflush(stdout);
for(i=0; i<(NUM_FWKNOP_ACCESS_TYPES); i++)
{
if(fwc.chain[i].target[0] == '\0')
continue;
zero_cmd_buffers();
/* Create the list command
*/
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_LIST_ALL_RULES_ARGS,
opts->fw_config->fw_command,
ch[i].table
);
res = system(cmd_buf);
if (opts->verbose)
log_msg(LOG_INFO, "fw_dump_rules() CMD: '%s' (res: %d)",
cmd_buf, res);
/* Expect full success on this */
if(! EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
got_err++;
}
}
}
else
{
fprintf(stdout, "Listing rules in fwknopd iptables chains...\n");
fflush(stdout);
for(i=0; i<(NUM_FWKNOP_ACCESS_TYPES); i++)
{
if(fwc.chain[i].target[0] == '\0')
continue;
zero_cmd_buffers();
/* Create the list command
*/
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_LIST_RULES_ARGS,
opts->fw_config->fw_command,
ch[i].table,
ch[i].to_chain
);
res = system(cmd_buf);
if (opts->verbose)
log_msg(LOG_INFO, "fw_dump_rules() CMD: '%s' (res: %d)",
cmd_buf, res);
/* Expect full success on this */
if(! EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
got_err++;
}
}
}
return(got_err);
}
/* Quietly flush and delete all fwknop custom chains.
*/
static void
delete_all_chains(const fko_srv_options_t *opts)
{
int i, res;
int jump_rule_num;
for(i=0; i<(NUM_FWKNOP_ACCESS_TYPES); i++)
{
if(fwc.chain[i].target[0] == '\0')
continue;
/* First look for a jump rule to this chain and remove it if it
* is there.
*/
if((jump_rule_num = jump_rule_exists(i)) > 0)
{
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_DEL_RULE_ARGS,
fwc.fw_command,
fwc.chain[i].table,
fwc.chain[i].from_chain,
jump_rule_num
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, 0);
if (opts->verbose)
log_msg(LOG_INFO, "delete_all_chains() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
/* Expect full success on this */
if(! EXTCMD_IS_SUCCESS(res))
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
}
zero_cmd_buffers();
/* Now flush and remove the chain.
*/
snprintf(cmd_buf, CMD_BUFSIZE-1,
"(%s " IPT_FLUSH_CHAIN_ARGS "; %s " IPT_DEL_CHAIN_ARGS ")", // > /dev/null 2>&1",
fwc.fw_command,
fwc.chain[i].table,
fwc.chain[i].to_chain,
fwc.fw_command,
fwc.chain[i].table,
fwc.chain[i].to_chain
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, 0);
if (opts->verbose)
log_msg(LOG_INFO, "delete_all_chains() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
/* Expect full success on this */
if(! EXTCMD_IS_SUCCESS(res))
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
}
}
/* Create the fwknop custom chains (at least those that are configured).
*/
static int
create_fw_chains(const fko_srv_options_t *opts)
{
int i;
int res, got_err = 0;
for(i=0; i<(NUM_FWKNOP_ACCESS_TYPES); i++)
{
if(fwc.chain[i].target[0] == '\0')
continue;
zero_cmd_buffers();
/* Create the custom chain.
*/
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_NEW_CHAIN_ARGS,
fwc.fw_command,
fwc.chain[i].table,
fwc.chain[i].to_chain
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, 0);
if (opts->verbose)
log_msg(LOG_INFO, "create_fw_chains() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
/* Expect full success on this */
if(! EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
got_err++;
}
/* Then create the jump rule to that chain.
*/
res = add_jump_rule(opts, i);
/* Expect full success on this */
if(! EXTCMD_IS_SUCCESS(res))
got_err++;
}
return(got_err);
}
static void
set_fw_chain_conf(const int type, char *conf_str)
{
int i, j;
char tbuf[1024] = {0};
char *ndx = conf_str;
char *chain_fields[FW_NUM_CHAIN_FIELDS];
struct fw_chain *chain = &(fwc.chain[type]);
chain->type = type;
if(ndx != NULL)
chain_fields[0] = tbuf;
i = 0;
j = 1;
while(*ndx != '\0')
{
if(*ndx != ' ')
{
if(*ndx == ',')
{
tbuf[i] = '\0';
chain_fields[j++] = &(tbuf[++i]);
}
else
tbuf[i++] = *ndx;
}
ndx++;
}
/* Sanity check - j should be the number of chain fields
* (excluding the type).
*/
if(j != FW_NUM_CHAIN_FIELDS)
{
fprintf(stderr, "[*] Custom Chain config parse error.\n"
"Wrong number of fields for chain type %i\n"
"Line: %s\n", type, conf_str);
exit(EXIT_FAILURE);
}
/* Pull and set Target */
strlcpy(chain->target, chain_fields[0], MAX_TARGET_NAME_LEN);
/* Pull and set Table */
strlcpy(chain->table, chain_fields[1], MAX_TABLE_NAME_LEN);
/* Pull and set From_chain */
strlcpy(chain->from_chain, chain_fields[2], MAX_CHAIN_NAME_LEN);
/* Pull and set Jump_rule_position */
chain->jump_rule_pos = atoi(chain_fields[3]);
/* Pull and set To_chain */
strlcpy(chain->to_chain, chain_fields[4], MAX_CHAIN_NAME_LEN);
/* Pull and set Jump_rule_position */
chain->rule_pos = atoi(chain_fields[5]);
}
void
fw_config_init(fko_srv_options_t *opts)
{
memset(&fwc, 0x0, sizeof(struct fw_config));
/* Set our firewall exe command path (iptables in most cases).
*/
strlcpy(fwc.fw_command, opts->config[CONF_FIREWALL_EXE], MAX_PATH_LEN);
/* Pull the fwknop chain config info and setup our internal
* config struct. The IPT_INPUT is the only one that is
* required. The rest are optional.
*/
set_fw_chain_conf(IPT_INPUT_ACCESS, opts->config[CONF_IPT_INPUT_ACCESS]);
/* The FWKNOP_OUTPUT_ACCESS requires ENABLE_IPT_OUTPUT_ACCESS be Y
*/
if(strncasecmp(opts->config[CONF_ENABLE_IPT_OUTPUT], "Y", 1)==0)
set_fw_chain_conf(IPT_OUTPUT_ACCESS, opts->config[CONF_IPT_OUTPUT_ACCESS]);
/* The remaining access chains require ENABLE_IPT_FORWARDING = Y
*/
if(strncasecmp(opts->config[CONF_ENABLE_IPT_FORWARDING], "Y", 1)==0)
{
set_fw_chain_conf(IPT_FORWARD_ACCESS, opts->config[CONF_IPT_FORWARD_ACCESS]);
set_fw_chain_conf(IPT_DNAT_ACCESS, opts->config[CONF_IPT_DNAT_ACCESS]);
/* SNAT (whichever mode) requires ENABLE_IPT_SNAT = Y
*/
if(strncasecmp(opts->config[CONF_ENABLE_IPT_SNAT], "Y", 1)==0)
{
/* If an SNAT_TRANSLATE_IP is specified use the SNAT_ACCESS mode.
* Otherwise, use MASQUERADE_ACCESS.
*
* XXX: --DSS: Not sure if using the TRANSLATE_IP parameter as
* the determining factor is the best why to handle
* this.
*
*/
if(opts->config[CONF_SNAT_TRANSLATE_IP] != NULL
&& strncasecmp(opts->config[CONF_SNAT_TRANSLATE_IP], "__CHANGEME__", 10)!=0)
set_fw_chain_conf(IPT_SNAT_ACCESS, opts->config[CONF_IPT_SNAT_ACCESS]);
else
set_fw_chain_conf(IPT_MASQUERADE_ACCESS, opts->config[CONF_IPT_MASQUERADE_ACCESS]);
}
}
/* Let us find it via our opts struct as well.
*/
opts->fw_config = &fwc;
return;
}
void
fw_initialize(const fko_srv_options_t *opts)
{
int res;
/* Flush the chains (just in case) so we can start fresh.
*/
delete_all_chains(opts);
/* Now create any configured chains.
*/
res = create_fw_chains(opts);
if(res != 0)
{
fprintf(stderr, "Warning: Errors detected during fwknop custom chain creation.\n");
exit(EXIT_FAILURE);
}
}
int
fw_cleanup(const fko_srv_options_t *opts)
{
delete_all_chains(opts);
return(0);
}
/****************************************************************************/
/* Rule Processing - Create an access request...
*/
int
process_spa_request(const fko_srv_options_t *opts, const acc_stanza_t *acc, spa_data_t *spadat)
{
char nat_ip[MAX_IPV4_STR_LEN] = {0};
char snat_target[SNAT_TARGET_BUFSIZE] = {0};
char *ndx;
unsigned int nat_port = 0;
acc_port_list_t *port_list = NULL;
acc_port_list_t *ple;
unsigned int fst_proto;
unsigned int fst_port;
struct fw_chain *in_chain = &(opts->fw_config->chain[IPT_INPUT_ACCESS]);
struct fw_chain *out_chain = &(opts->fw_config->chain[IPT_OUTPUT_ACCESS]);
struct fw_chain *fwd_chain = &(opts->fw_config->chain[IPT_FORWARD_ACCESS]);
struct fw_chain *dnat_chain = &(opts->fw_config->chain[IPT_DNAT_ACCESS]);
struct fw_chain *snat_chain; /* We assign this later (if we need to). */
int res = 0;
time_t now;
unsigned int exp_ts;
/* Parse and expand our access message.
*/
expand_acc_port_list(&port_list, spadat->spa_message_remain);
/* Start at the top of the proto-port list...
*/
ple = port_list;
/* Remember the first proto/port combo in case we need them
* for NAT access requests.
*/
fst_proto = ple->proto;
fst_port = ple->port;
/* Set our expire time value.
*/
time(&now);
exp_ts = now + spadat->fw_access_timeout;
/* For straight access requests, we currently support multiple proto/port
* request.
*/
if((spadat->message_type == FKO_ACCESS_MSG
|| spadat->message_type == FKO_CLIENT_TIMEOUT_ACCESS_MSG) && !acc->force_nat)
{
/* Check to make sure that the jump rules exist for each
* required chain
*/
if(jump_rule_exists(IPT_INPUT_ACCESS) == 0)
add_jump_rule(opts, IPT_INPUT_ACCESS);
if(out_chain->to_chain != NULL && strlen(out_chain->to_chain))
if(jump_rule_exists(IPT_OUTPUT_ACCESS) == 0)
add_jump_rule(opts, IPT_OUTPUT_ACCESS);
/* Create an access command for each proto/port for the source ip.
*/
while(ple != NULL)
{
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_ADD_RULE_ARGS,
opts->fw_config->fw_command,
in_chain->table,
in_chain->to_chain,
ple->proto,
spadat->use_src_ip,
ple->port,
exp_ts,
in_chain->target
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, 0);
if (opts->verbose)
log_msg(LOG_INFO, "process_spa_request() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_INFO, "Added Rule to %s for %s, %s expires at %u",
in_chain->to_chain, spadat->use_src_ip,
spadat->spa_message_remain, exp_ts
);
in_chain->active_rules++;
/* Reset the next expected expire time for this chain if it
* is warranted.
*/
if(in_chain->next_expire < now || exp_ts < in_chain->next_expire)
in_chain->next_expire = exp_ts;
}
else
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
/* If we have to make an corresponding OUTPUT rule if out_chain target
* is not NULL.
*/
if(out_chain->to_chain != NULL && strlen(out_chain->to_chain))
{
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_ADD_OUT_RULE_ARGS,
opts->fw_config->fw_command,
out_chain->table,
out_chain->to_chain,
ple->proto,
spadat->use_src_ip,
ple->port,
exp_ts,
out_chain->target
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, 0);
if (opts->verbose)
log_msg(LOG_INFO, "process_spa_request() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_INFO, "Added OUTPUT Rule to %s for %s, %s expires at %u",
out_chain->to_chain, spadat->use_src_ip,
spadat->spa_message_remain, exp_ts
);
out_chain->active_rules++;
/* Reset the next expected expire time for this chain if it
* is warranted.
*/
if(out_chain->next_expire < now || exp_ts < out_chain->next_expire)
out_chain->next_expire = exp_ts;
}
else
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
}
ple = ple->next;
}
}
/* NAT requests... */
else if(spadat->message_type == FKO_LOCAL_NAT_ACCESS_MSG
|| spadat->message_type == FKO_CLIENT_TIMEOUT_LOCAL_NAT_ACCESS_MSG
|| spadat->message_type == FKO_NAT_ACCESS_MSG
|| spadat->message_type == FKO_CLIENT_TIMEOUT_NAT_ACCESS_MSG
|| acc->force_nat)
{
/* Parse out the NAT IP and Port components.
*/
if(acc->force_nat)
{
strlcpy(nat_ip, acc->force_nat_ip, MAX_IPV4_STR_LEN);
nat_port = acc->force_nat_port;
}
else
{
ndx = strchr(spadat->nat_access, ',');
if(ndx != NULL)
{
strlcpy(nat_ip, spadat->nat_access, (ndx-spadat->nat_access)+1);
nat_port = atoi(ndx+1);
}
}
/* Make our FORWARD and NAT rules
*/
if(fwd_chain->to_chain != NULL && strlen(fwd_chain->to_chain))
{
/* Make sure the required jump rule exists
*/
if (jump_rule_exists(IPT_FORWARD_ACCESS) == 0)
add_jump_rule(opts, IPT_FORWARD_ACCESS);
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_ADD_FWD_RULE_ARGS,
opts->fw_config->fw_command,
fwd_chain->table,
fwd_chain->to_chain,
fst_proto,
spadat->use_src_ip,
nat_ip,
nat_port,
exp_ts,
fwd_chain->target
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, 0);
if (opts->verbose)
log_msg(LOG_INFO, "process_spa_request() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_INFO, "Added FORWARD Rule to %s for %s, %s expires at %u",
fwd_chain->to_chain, spadat->use_src_ip,
spadat->spa_message_remain, exp_ts
);
fwd_chain->active_rules++;
/* Reset the next expected expire time for this chain if it
* is warranted.
*/
if(fwd_chain->next_expire < now || exp_ts < fwd_chain->next_expire)
fwd_chain->next_expire = exp_ts;
}
else
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
}
if(dnat_chain->to_chain != NULL && strlen(dnat_chain->to_chain))
{
/* Make sure the required jump rule exists
*/
if (jump_rule_exists(IPT_DNAT_ACCESS) == 0)
add_jump_rule(opts, IPT_DNAT_ACCESS);
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_ADD_DNAT_RULE_ARGS,
opts->fw_config->fw_command,
dnat_chain->table,
dnat_chain->to_chain,
fst_proto,
spadat->use_src_ip,
fst_port,
exp_ts,
dnat_chain->target,
nat_ip,
nat_port
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, 0);
if (opts->verbose)
log_msg(LOG_INFO, "process_spa_request() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_INFO, "Added DNAT Rule to %s for %s, %s expires at %u",
dnat_chain->to_chain, spadat->use_src_ip,
spadat->spa_message_remain, exp_ts
);
dnat_chain->active_rules++;
/* Reset the next expected expire time for this chain if it
* is warranted.
*/
if(dnat_chain->next_expire < now || exp_ts < dnat_chain->next_expire)
dnat_chain->next_expire = exp_ts;
}
else
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
}
/* If SNAT (or MASQUERADE) is wanted, then we add those rules here as well.
*/
if(strncasecmp(opts->config[CONF_ENABLE_IPT_SNAT], "Y", 1) == 0)
{
zero_cmd_buffers();
/* Setup some parameter depending on whether we are using SNAT
* or MASQUERADE.
*/
if(strncasecmp(opts->config[CONF_SNAT_TRANSLATE_IP], "__CHANGEME__", 10)!=0)
{
/* Using static SNAT */
snat_chain = &(opts->fw_config->chain[IPT_SNAT_ACCESS]);
snprintf(snat_target, SNAT_TARGET_BUFSIZE-1,
"--to-source %s:%i", opts->config[CONF_SNAT_TRANSLATE_IP],
fst_port);
}
else
{
/* Using MASQUERADE */
snat_chain = &(opts->fw_config->chain[IPT_MASQUERADE_ACCESS]);
snprintf(snat_target, SNAT_TARGET_BUFSIZE-1,
"--to-ports %i", fst_port);
}
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_ADD_SNAT_RULE_ARGS,
opts->fw_config->fw_command,
snat_chain->table,
snat_chain->to_chain,
fst_proto,
nat_ip,
nat_port,
exp_ts,
snat_chain->target,
snat_target
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, 0);
if (opts->verbose)
log_msg(LOG_INFO, "process_spa_request() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_INFO, "Added Source NAT Rule to %s for %s, %s expires at %u",
snat_chain->to_chain, spadat->use_src_ip,
spadat->spa_message_remain, exp_ts
);
snat_chain->active_rules++;
/* Reset the next expected expire time for this chain if it
* is warranted.
*/
if(snat_chain->next_expire < now || exp_ts < snat_chain->next_expire)
snat_chain->next_expire = exp_ts;
}
else
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
}
}
/* Done with the port list for access rules.
*/
free_acc_port_list(port_list);
return(res);
}
/* Iterate over the configure firewall access chains and purge expired
* firewall rules.
*/
void
check_firewall_rules(const fko_srv_options_t *opts)
{
char exp_str[12];
char rule_num_str[6];
char *ndx, *rn_start, *rn_end, *tmp_mark;
int i, res, rn_offset;
time_t now, rule_exp, min_exp = 0;
struct fw_chain *ch = opts->fw_config->chain;
time(&now);
/* Iterate over each chain and look for active rules to delete.
*/
for(i = 0; i < NUM_FWKNOP_ACCESS_TYPES; i++)
{
/* If there are no active rules or we have not yet
* reached our expected next expire time, continue.
*/
if(ch[i].active_rules == 0 || ch[i].next_expire > now)
continue;
zero_cmd_buffers();
rn_offset = 0;
/* There should be a rule to delete. Get the current list of
* rules for this chain and delete the ones that are expired.
*/
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_LIST_RULES_ARGS,
opts->fw_config->fw_command,
ch[i].table,
ch[i].to_chain
);
res = run_extcmd(cmd_buf, cmd_out, STANDARD_CMD_OUT_BUFSIZE, 0);
if (opts->verbose)
log_msg(LOG_INFO, "check_firewall_rules() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(!EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, cmd_out);
continue;
}
if(opts->verbose > 1)
log_msg(LOG_INFO, "RES=%i, CMD_BUF: %s\nRULES LIST: %s", res, cmd_buf, cmd_out);
ndx = strstr(cmd_out, EXPIRE_COMMENT_PREFIX);
if(ndx == NULL)
{
/* we did not find an expected rule.
*/
log_msg(LOG_ERR,
"Did not find expire comment in rules list %i.\n", i);
if (ch[i].active_rules > 0)
ch[i].active_rules--;
continue;
}
/* walk the list and process rules as needed.
*/
while (ndx != NULL) {
/* Jump forward and extract the timestamp
*/
ndx += strlen(EXPIRE_COMMENT_PREFIX);
/* remember this spot for when we look for the next
* rule.
*/
tmp_mark = ndx;
strlcpy(exp_str, ndx, 11);
rule_exp = (time_t)atoll(exp_str);
if(rule_exp <= now)
{
/* Backtrack and get the rule number and delete it.
*/
rn_start = ndx;
while(--rn_start > cmd_out)
{
if(*rn_start == '\n')
break;
}
if(*rn_start != '\n')
{
/* This should not happen. But if it does, complain,
* decrement the active rule value, and go on.
*/
log_msg(LOG_ERR,
"Rule parse error while finding rule line start in chain %i", i);
if (ch[i].active_rules > 0)
ch[i].active_rules--;
break;
}
rn_start++;
rn_end = strchr(rn_start, ' ');
if(rn_end == NULL)
{
/* This should not happen. But if it does, complain,
* decrement the active rule value, and go on.
*/
log_msg(LOG_ERR,
"Rule parse error while finding rule number in chain %i", i);
if (ch[i].active_rules > 0)
ch[i].active_rules--;
break;
}
strlcpy(rule_num_str, rn_start, (rn_end - rn_start)+1);
zero_cmd_buffers();
snprintf(cmd_buf, CMD_BUFSIZE-1, "%s " IPT_DEL_RULE_ARGS,
opts->fw_config->fw_command,
ch[i].table,
ch[i].to_chain,
atoi(rule_num_str) - rn_offset
);
res = run_extcmd(cmd_buf, err_buf, CMD_BUFSIZE, 0);
if (opts->verbose)
log_msg(LOG_INFO, "check_firewall_rules() CMD: '%s' (res: %d, err: %s)",
cmd_buf, res, err_buf);
if(EXTCMD_IS_SUCCESS(res))
{
log_msg(LOG_INFO, "Removed rule %s from %s with expire time of %u.",
rule_num_str, ch[i].to_chain, rule_exp
);
rn_offset++;
if (ch[i].active_rules > 0)
ch[i].active_rules--;
}
else
log_msg(LOG_ERR, "Error %i from cmd:'%s': %s", res, cmd_buf, err_buf);
}
else
{
/* Track the minimum future rule expire time.
*/
if(rule_exp > now)
min_exp = (min_exp < rule_exp) ? min_exp : rule_exp;
}
/* Push our tracking index forward beyond (just processed) _exp_
* string so we can continue to the next rule in the list.
*/
ndx = strstr(tmp_mark, EXPIRE_COMMENT_PREFIX);
}
/* Set the next pending expire time accordingly. 0 if there are no
* more rules, or whatever the next expected (min_exp) time will be.
*/
if(ch[i].active_rules < 1)
ch[i].next_expire = 0;
else if(min_exp)
ch[i].next_expire = min_exp;
}
}
#endif /* FIREWALL_IPTABLES */
/***EOF***/
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