/**
 * @file config.c
 * @note Copyright (C) 2011 Richard Cochran <richardcochran@gmail.com>
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
#include <ctype.h>
#include <float.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "config.h"
#include "ether.h"
#include "hash.h"
#include "print.h"
#include "util.h"

enum config_section {
	GLOBAL_SECTION,
	PORT_SECTION,
	UNKNOWN_SECTION,
};

enum config_type {
	CFG_TYPE_INT,
	CFG_TYPE_DOUBLE,
};

typedef union {
	int i;
	double d;
} any_t;

#define CONFIG_LABEL_SIZE 32

#define CFG_ITEM_STATIC (1 << 0) /* statically allocated, not to be freed */
#define CFG_ITEM_LOCKED (1 << 1) /* command line value, may not be changed */
#define CFG_ITEM_PORT   (1 << 2) /* item may appear in port sections */

struct config_item {
	char label[CONFIG_LABEL_SIZE];
	enum config_type type;
	unsigned int flags;
	any_t val;
	any_t min;
	any_t max;
};

#define N_CONFIG_ITEMS (sizeof(config_tab) / sizeof(config_tab[0]))

#define CONFIG_ITEM_DBL(_label, _port, _default, _min, _max) {	\
	.label	= _label,				\
	.type	= CFG_TYPE_DOUBLE,			\
	.flags	= _port ? CFG_ITEM_PORT : 0,		\
	.val.d	= _default,				\
	.min.d	= _min,					\
	.max.d	= _max,					\
}
#define CONFIG_ITEM_INT(_label, _port, _default, _min, _max) {	\
	.label	= _label,				\
	.type	= CFG_TYPE_INT,				\
	.flags	= _port ? CFG_ITEM_PORT : 0,		\
	.val.i	= _default,				\
	.min.i	= _min,					\
	.max.i	= _max,					\
}

#define GLOB_ITEM_DBL(label, _default, min, max) \
	CONFIG_ITEM_DBL(label, 0, _default, min, max)

#define GLOB_ITEM_INT(label, _default, min, max) \
	CONFIG_ITEM_INT(label, 0, _default, min, max)

#define PORT_ITEM_DBL(label, _default, min, max) \
	CONFIG_ITEM_DBL(label, 1, _default, min, max)

#define PORT_ITEM_INT(label, _default, min, max) \
	CONFIG_ITEM_INT(label, 1, _default, min, max)

struct config_item config_tab[] = {
	PORT_ITEM_INT("announceReceiptTimeout", 3, 2, UINT8_MAX),
	GLOB_ITEM_INT("assume_two_step", 0, 0, 1),
	GLOB_ITEM_INT("check_fup_sync", 0, 0, 1),
	PORT_ITEM_INT("delayAsymmetry", 0, INT_MIN, INT_MAX),
	GLOB_ITEM_DBL("first_step_threshold", 0.00002, 0.0, DBL_MAX),
	PORT_ITEM_INT("follow_up_info", 0, 0, 1),
	PORT_ITEM_INT("freq_est_interval", 1, 0, INT_MAX),
	PORT_ITEM_INT("logAnnounceInterval", 1, INT8_MIN, INT8_MAX),
	PORT_ITEM_INT("logMinDelayReqInterval", 0, INT8_MIN, INT8_MAX),
	PORT_ITEM_INT("logMinPdelayReqInterval", 0, INT8_MIN, INT8_MAX),
	PORT_ITEM_INT("logSyncInterval", 0, INT8_MIN, INT8_MAX),
	GLOB_ITEM_INT("logging_level", LOG_INFO, PRINT_LEVEL_MIN, PRINT_LEVEL_MAX),
	GLOB_ITEM_INT("max_frequency", 900000000, 0, INT_MAX),
	PORT_ITEM_INT("neighborPropDelayThresh", 20000000, 0, INT_MAX),
	GLOB_ITEM_INT("ntpshm_segment", 0, INT_MIN, INT_MAX),
	PORT_ITEM_INT("path_trace_enabled", 0, 0, 1),
	GLOB_ITEM_DBL("pi_integral_const", 0.0, 0.0, DBL_MAX),
	GLOB_ITEM_DBL("pi_integral_exponent", 0.4, -DBL_MAX, DBL_MAX),
	GLOB_ITEM_DBL("pi_integral_norm_max", 0.3, DBL_MIN, 2.0),
	GLOB_ITEM_DBL("pi_integral_scale", 0.0, 0.0, DBL_MAX),
	GLOB_ITEM_DBL("pi_proportional_const", 0.0, 0.0, DBL_MAX),
	GLOB_ITEM_DBL("pi_proportional_exponent", -0.3, -DBL_MAX, DBL_MAX),
	GLOB_ITEM_DBL("pi_proportional_norm_max", 0.7, DBL_MIN, 1.0),
	GLOB_ITEM_DBL("pi_proportional_scale", 0.0, 0.0, DBL_MAX),
	GLOB_ITEM_DBL("step_threshold", 0.0, 0.0, DBL_MAX),
	PORT_ITEM_INT("syncReceiptTimeout", 0, 0, UINT8_MAX),
	PORT_ITEM_INT("transportSpecific", 0, 0, 0x0F),
	GLOB_ITEM_INT("tx_timestamp_timeout", 1, 1, INT_MAX),
	PORT_ITEM_INT("udp_ttl", 1, 1, 255),
	GLOB_ITEM_INT("use_syslog", 1, 0, 1),
	GLOB_ITEM_INT("verbose", 0, 0, 1),
};

static struct config_item *config_section_item(struct config *cfg,
					       const char *section,
					       const char *name)
{
	char buf[CONFIG_LABEL_SIZE + MAX_IFNAME_SIZE];

	snprintf(buf, sizeof(buf), "%s.%s", section, name);
	return hash_lookup(cfg->htab, buf);
}

static struct config_item *config_global_item(struct config *cfg,
					      const char *name)
{
	return config_section_item(cfg, "global", name);
}

static struct config_item *config_find_item(struct config *cfg,
					    const char *section,
					    const char *name)
{
	struct config_item *ci;
	if (section) {
		ci = config_section_item(cfg, section, name);
		if (ci) {
			return ci;
		}
	}
	return config_global_item(cfg, name);
}

static struct config_item *config_item_alloc(struct config *cfg,
					     const char *section,
					     const char *name,
					     enum config_type type)
{
	struct config_item *ci;
	char buf[CONFIG_LABEL_SIZE + MAX_IFNAME_SIZE];

	ci = calloc(1, sizeof(*ci));
	if (!ci) {
		fprintf(stderr, "low memory\n");
		return NULL;
	}
	strncpy(ci->label, name, CONFIG_LABEL_SIZE - 1);
	ci->type = type;

	snprintf(buf, sizeof(buf), "%s.%s", section, ci->label);
	if (hash_insert(cfg->htab, buf, ci)) {
		fprintf(stderr, "low memory or duplicate item %s\n", name);
		free(ci);
		return NULL;
	}

	return ci;
}

static void config_item_free(void *ptr)
{
	struct config_item *ci = ptr;
	if (ci->flags & CFG_ITEM_STATIC)
		return;
	free(ci);
}

static enum parser_result parse_section_line(char *s, enum config_section *section)
{
	if (!strcasecmp(s, "[global]")) {
		*section = GLOBAL_SECTION;
	} else if (s[0] == '[') {
		char c;
		*section = PORT_SECTION;
		/* Replace square brackets with white space. */
		while (0 != (c = *s)) {
			if (c == '[' || c == ']')
				*s = ' ';
			s++;
		}
	} else
		return NOT_PARSED;
	return PARSED_OK;
}

static enum parser_result parse_item(struct config *cfg,
				     const char *section,
				     const char *option,
				     const char *value)
{
	struct config_item *cgi, *dst;
	enum parser_result r = BAD_VALUE;
	double df;
	int val;

	/* If there is no default value, then the option is bogus. */
	cgi = config_global_item(cfg, option);
	if (!cgi) {
		return NOT_PARSED;
	}

	switch (cgi->type) {
	case CFG_TYPE_INT:
		r = get_ranged_int(value, &val, cgi->min.i, cgi->max.i);
		break;
	case CFG_TYPE_DOUBLE:
		r = get_ranged_double(value, &df, cgi->min.d, cgi->max.d);
		break;
	}
	if (r != PARSED_OK) {
		return r;
	}

	if (section) {
		if (!(cgi->flags & CFG_ITEM_PORT)) {
			return NOT_PARSED;
		}
		/* Create or update this port specific item. */
		dst = config_section_item(cfg, section, option);
		if (!dst) {
			dst = config_item_alloc(cfg, section, option, cgi->type);
			if (!dst) {
				return NOT_PARSED;
			}
		}
	} else if (cgi->flags & CFG_ITEM_LOCKED) {
		/* This global option was set on the command line. */
		return PARSED_OK;
	} else {
		/* Update the global default value. */
		dst = cgi;
	}

	switch (dst->type) {
	case CFG_TYPE_INT:
		dst->val.i = val;
		break;
	case CFG_TYPE_DOUBLE:
		dst->val.d = df;
		break;
	}
	return PARSED_OK;
}

static enum parser_result parse_pod_setting(const char *option,
					    const char *value,
					    struct port_defaults *pod)
{
	int val;
	enum parser_result r;

	if (!strcmp(option, "min_neighbor_prop_delay")) {
		r = get_ranged_int(value, &val, INT_MIN, -1);
		if (r != PARSED_OK)
			return r;
		pod->min_neighbor_prop_delay = val;

	} else if (!strcmp(option, "egressLatency")) {
		r = get_ranged_int(value, &val, INT_MIN, INT_MAX);
		if (r != PARSED_OK)
			return r;
		pod->tx_timestamp_offset = val;

	} else if (!strcmp(option, "ingressLatency")) {
		r = get_ranged_int(value, &val, INT_MIN, INT_MAX);
		if (r != PARSED_OK)
			return r;
		pod->rx_timestamp_offset = val;

	} else if (!strcmp(option, "fault_badpeernet_interval")) {
		pod->flt_interval_pertype[FT_BAD_PEER_NETWORK].type = FTMO_LINEAR_SECONDS;
		if (!strcasecmp("ASAP", value)) {
			pod->flt_interval_pertype[FT_BAD_PEER_NETWORK].val = 0;
		} else {
			r = get_ranged_int(value, &val, INT32_MIN, INT32_MAX);
			if (r != PARSED_OK)
				return r;
			pod->flt_interval_pertype[FT_BAD_PEER_NETWORK].val = val;
		}

	} else if (!strcmp(option, "fault_reset_interval")) {
		pod->flt_interval_pertype[FT_UNSPECIFIED].type = FTMO_LOG2_SECONDS;
		if (!strcasecmp("ASAP", value)) {
			pod->flt_interval_pertype[FT_UNSPECIFIED].val = FRI_ASAP;
		} else {
			r = get_ranged_int(value, &val, INT8_MIN, INT8_MAX);
			if (r != PARSED_OK)
				return r;
			pod->flt_interval_pertype[FT_UNSPECIFIED].val = val;
		}

	} else
		return NOT_PARSED;

	return PARSED_OK;
}

static enum parser_result parse_port_setting(struct config *cfg,
					     const char *option,
					     const char *value,
					     struct interface *iface)
{
	enum parser_result r;
	int val;

	r = parse_pod_setting(option, value, &iface->pod);
	if (r != NOT_PARSED)
		return r;

	if (!strcmp(option, "network_transport")) {
		if (!strcasecmp("L2", value))
			iface->transport = TRANS_IEEE_802_3;
		else if (!strcasecmp("UDPv4", value))
			iface->transport = TRANS_UDP_IPV4;
		else if (!strcasecmp("UDPv6", value))
			iface->transport = TRANS_UDP_IPV6;
		else
			return BAD_VALUE;

	} else if (!strcmp(option, "delay_mechanism")) {
		if (!strcasecmp("Auto", value))
			iface->dm = DM_AUTO;
		else if (!strcasecmp("E2E", value))
			iface->dm = DM_E2E;
		else if (!strcasecmp("P2P", value))
			iface->dm = DM_P2P;
		else
			return BAD_VALUE;

	} else if (!strcmp(option, "tsproc_mode")) {
		if (!strcasecmp("filter", value))
			iface->tsproc_mode = TSPROC_FILTER;
		else if (!strcasecmp("raw", value))
			iface->tsproc_mode = TSPROC_RAW;
		else if (!strcasecmp("filter_weight", value))
			iface->tsproc_mode = TSPROC_FILTER_WEIGHT;
		else if (!strcasecmp("raw_weight", value))
			iface->tsproc_mode = TSPROC_RAW_WEIGHT;
		else
			return BAD_VALUE;

	} else if (!strcmp(option, "delay_filter")) {
		if (!strcasecmp("moving_average", value))
			iface->delay_filter = FILTER_MOVING_AVERAGE;
		else if (!strcasecmp("moving_median", value))
			iface->delay_filter = FILTER_MOVING_MEDIAN;
		else
			return BAD_VALUE;

	} else if (!strcmp(option, "delay_filter_length")) {
		r = get_ranged_int(value, &val, 1, INT_MAX);
		if (r != PARSED_OK)
			return r;
		iface->delay_filter_length = val;

	} else if (!strcmp(option, "boundary_clock_jbod")) {
		r = get_ranged_int(value, &val, 0, 1);
		if (r != PARSED_OK)
			return r;
		iface->boundary_clock_jbod = val;

	} else
		return parse_item(cfg, iface->name, option, value);

	return PARSED_OK;
}

static int count_char(const char *str, char c)
{
	int num = 0;
	char s;
	while ((s = *(str++))) {
		if (s == c)
			num++;
	}
	return num;
}

static enum parser_result parse_global_setting(const char *option,
					       const char *value,
					       struct config *cfg)
{
	int i, val, cfg_ignore = cfg->cfg_ignore;
	unsigned int uval;
	unsigned char mac[MAC_LEN];
	unsigned char oui[OUI_LEN];

	struct defaultDS *dds = &cfg->dds.dds;
	struct port_defaults *pod = &cfg->pod;

	enum parser_result r;

	r = parse_pod_setting(option, value, pod);
	if (r != NOT_PARSED)
		return r;

	if (!strcmp(option, "twoStepFlag")) {
		r = get_ranged_int(value, &val, 0, 1);
		if (r != PARSED_OK)
			return r;
		if (val)
			dds->flags |=  DDS_TWO_STEP_FLAG;
		else
			dds->flags &= ~DDS_TWO_STEP_FLAG;

	} else if (!strcmp(option, "slaveOnly")) {
		r = get_ranged_int(value, &val, 0, 1);
		if (r != PARSED_OK)
			return r;
		if (!(cfg_ignore & CFG_IGNORE_SLAVEONLY)) {
			if (val)
				dds->flags |=  DDS_SLAVE_ONLY;
			else
				dds->flags &= ~DDS_SLAVE_ONLY;
		}

	} else if (!strcmp(option, "gmCapable")) {
		r = get_ranged_int(value, &val, 0, 1);
		if (r != PARSED_OK)
			return r;
		cfg->dds.grand_master_capable = val;

	} else if (!strcmp(option, "priority1")) {
		r = get_ranged_uint(value, &uval, 0, UINT8_MAX);
		if (r != PARSED_OK)
			return r;
		dds->priority1 = uval;

	} else if (!strcmp(option, "priority2")) {
		r = get_ranged_uint(value, &uval, 0, UINT8_MAX);
		if (r != PARSED_OK)
			return r;
		dds->priority2 = uval;

	} else if (!strcmp(option, "domainNumber")) {
		r = get_ranged_uint(value, &uval, 0, 127);
		if (r != PARSED_OK)
			return r;
		dds->domainNumber = uval;

	} else if (!strcmp(option, "clockClass")) {
		r = get_ranged_uint(value, &uval, 0, UINT8_MAX);
		if (r != PARSED_OK)
			return r;
		if (!(cfg_ignore & CFG_IGNORE_SLAVEONLY))
			dds->clockQuality.clockClass = uval;

	} else if (!strcmp(option, "clockAccuracy")) {
		r = get_ranged_uint(value, &uval, 0, UINT8_MAX);
		if (r != PARSED_OK)
			return r;
		dds->clockQuality.clockAccuracy = uval;

	} else if (!strcmp(option, "offsetScaledLogVariance")) {
		r = get_ranged_uint(value, &uval, 0, UINT16_MAX);
		if (r != PARSED_OK)
			return r;
		dds->clockQuality.offsetScaledLogVariance = uval;

	} else if (!strcmp(option, "free_running")) {
		r = get_ranged_int(value, &val, 0, 1);
		if (r != PARSED_OK)
			return r;
		cfg->dds.free_running = val;

	} else if (!strcmp(option, "sanity_freq_limit")) {
		r = get_ranged_int(value, &val, 0, INT_MAX);
		if (r != PARSED_OK)
			return r;
		cfg->dds.sanity_freq_limit = val;

	} else if (!strcmp(option, "ptp_dst_mac")) {
		if (MAC_LEN != sscanf(value, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
				      &mac[0], &mac[1], &mac[2], &mac[3], &mac[4], &mac[5]))
			return BAD_VALUE;
		for (i = 0; i < MAC_LEN; i++)
			cfg->ptp_dst_mac[i] = mac[i];

	} else if (!strcmp(option, "p2p_dst_mac")) {
		if (MAC_LEN != sscanf(value, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
				      &mac[0], &mac[1], &mac[2], &mac[3], &mac[4], &mac[5]))
			return BAD_VALUE;
		for (i = 0; i < MAC_LEN; i++)
			cfg->p2p_dst_mac[i] = mac[i];

	} else if (!strcmp(option, "udp6_scope")) {
		r = get_ranged_uint(value, &uval, 0x00, 0x0F);
		if (r != PARSED_OK)
			return r;
		*cfg->udp6_scope = uval;

	} else if (!strcmp(option, "uds_address")) {
		if (strlen(value) > MAX_IFNAME_SIZE)
			return OUT_OF_RANGE;
		strncpy(cfg->uds_address, value, MAX_IFNAME_SIZE);

	} else if (!strcmp(option, "time_stamping")) {
		if (!(cfg_ignore & CFG_IGNORE_TIMESTAMPING)) {
			if (0 == strcasecmp("hardware", value))
				cfg->timestamping = TS_HARDWARE;
			else if (0 == strcasecmp("software", value))
				cfg->timestamping = TS_SOFTWARE;
			else if (0 == strcasecmp("legacy", value))
				cfg->timestamping = TS_LEGACY_HW;
			else
				return BAD_VALUE;
		}

	} else if (!strcmp(option, "delay_mechanism")) {
		if (!(cfg_ignore & CFG_IGNORE_DM)) {
			if (0 == strcasecmp("E2E", value))
				cfg->dm = DM_E2E;
			else if (0 == strcasecmp("P2P", value))
				cfg->dm = DM_P2P;
			else if (0 == strcasecmp("Auto", value))
				cfg->dm = DM_AUTO;
			else
				return BAD_VALUE;
		}

	} else if (!strcmp(option, "network_transport")) {
		if (!(cfg_ignore & CFG_IGNORE_TRANSPORT)) {
			if (!strcasecmp("UDPv4", value))
				cfg->transport = TRANS_UDP_IPV4;
			else if (!strcasecmp("UDPv6", value))
				cfg->transport = TRANS_UDP_IPV6;
			else if (!strcasecmp("L2", value))
				cfg->transport = TRANS_IEEE_802_3;
			else
				return BAD_VALUE;
		}

	} else if (!strcmp(option, "clock_servo")) {
		if (!strcasecmp("pi", value))
			cfg->clock_servo = CLOCK_SERVO_PI;
		else if (!strcasecmp("linreg", value))
			cfg->clock_servo = CLOCK_SERVO_LINREG;
		else if (!strcasecmp("ntpshm", value))
			cfg->clock_servo = CLOCK_SERVO_NTPSHM;
		else if (!strcasecmp("nullf", value))
			cfg->clock_servo = CLOCK_SERVO_NULLF;
		else
			return BAD_VALUE;

	} else if (!strcmp(option, "productDescription")) {
		if (count_char(value, ';') != 2)
			return BAD_VALUE;
		if (static_ptp_text_set(&cfg->dds.clock_desc.productDescription, value) != 0)
			return BAD_VALUE;

	} else if (!strcmp(option, "revisionData")) {
		if (count_char(value, ';') != 2)
			return BAD_VALUE;
		if (static_ptp_text_set(&cfg->dds.clock_desc.revisionData, value) != 0)
			return BAD_VALUE;

	} else if (!strcmp(option, "userDescription")) {
		if (static_ptp_text_set(&cfg->dds.clock_desc.userDescription, value) != 0)
			return BAD_VALUE;

	} else if (!strcmp(option, "manufacturerIdentity")) {
		if (OUI_LEN != sscanf(value, "%hhx:%hhx:%hhx",
				      &oui[0], &oui[1], &oui[2]))
			return BAD_VALUE;
		for (i = 0; i < OUI_LEN; i++)
			cfg->dds.clock_desc.manufacturerIdentity[i] = oui[i];

	} else if (!strcmp(option, "summary_interval")) {
		r = get_ranged_int(value, &val, INT_MIN, INT_MAX);
		if (r != PARSED_OK)
			return r;
		cfg->dds.stats_interval = val;

	} else if (!strcmp(option, "kernel_leap")) {
		r = get_ranged_int(value, &val, 0, 1);
		if (r != PARSED_OK)
			return r;
		cfg->dds.kernel_leap = val;

	} else if (!strcmp(option, "timeSource")) {
		r = get_ranged_int(value, &val, 0x10, 0xfe);
		if (r != PARSED_OK)
			return r;
		cfg->dds.time_source = val;

	} else if (!strcmp(option, "tsproc_mode")) {
		if (!strcasecmp("filter", value))
			cfg->dds.tsproc_mode = TSPROC_FILTER;
		else if (!strcasecmp("raw", value))
			cfg->dds.tsproc_mode = TSPROC_RAW;
		else if (!strcasecmp("filter_weight", value))
			cfg->dds.tsproc_mode = TSPROC_FILTER_WEIGHT;
		else if (!strcasecmp("raw_weight", value))
			cfg->dds.tsproc_mode = TSPROC_RAW_WEIGHT;
		else
			return BAD_VALUE;

	} else if (!strcmp(option, "delay_filter")) {
		if (!strcasecmp("moving_average", value))
			cfg->dds.delay_filter = FILTER_MOVING_AVERAGE;
		else if (!strcasecmp("moving_median", value))
			cfg->dds.delay_filter = FILTER_MOVING_MEDIAN;
		else
			return BAD_VALUE;

	} else if (!strcmp(option, "delay_filter_length")) {
		r = get_ranged_int(value, &val, 1, INT_MAX);
		if (r != PARSED_OK)
			return r;
		cfg->dds.delay_filter_length = val;

	} else if (!strcmp(option, "boundary_clock_jbod")) {
		r = get_ranged_int(value, &val, 0, 1);
		if (r != PARSED_OK)
			return r;
		cfg->dds.boundary_clock_jbod = val;

	} else
		return parse_item(cfg, NULL, option, value);

	return PARSED_OK;
}

static enum parser_result parse_setting_line(char *line,
					     const char **option,
					     const char **value)
{
	*option = line;

	while (!isspace(line[0])) {
		if (line[0] == '\0')
			return NOT_PARSED;
		line++;
	}

	while (isspace(line[0])) {
		line[0] = '\0';
		line++;
	}

	*value = line;

	return PARSED_OK;
}

static void check_deprecated_options(const char **option)
{
	const char *new_option = NULL;

	if (!strcmp(*option, "pi_offset_const")) {
		new_option = "step_threshold";
	} else if (!strcmp(*option, "pi_f_offset_const")) {
		new_option = "first_step_threshold";
	} else if (!strcmp(*option, "pi_max_frequency")) {
		new_option = "max_frequency";
	}

	if (new_option) {
		fprintf(stderr, "option %s is deprecated, please use %s instead\n",
				*option, new_option);
		*option = new_option;
	}
}

int config_read(char *name, struct config *cfg)
{
	enum config_section current_section = UNKNOWN_SECTION;
	enum parser_result parser_res;
	FILE *fp;
	char buf[1024], *line, *c;
	const char *option, *value;
	struct interface *current_port = NULL;
	int line_num;

	fp = 0 == strncmp(name, "-", 2) ? stdin : fopen(name, "r");

	if (!fp) {
		fprintf(stderr, "failed to open configuration file %s: %m\n", name);
		return -1;
	}

	for (line_num = 1; fgets(buf, sizeof(buf), fp); line_num++) {
		c = buf;

		/* skip whitespace characters */
		while (isspace(*c))
			c++;

		/* ignore empty lines and comments */
		if (*c == '#' || *c == '\n' || *c == '\0')
			continue;

		line = c;

		/* remove trailing whitespace characters and \n */
		c += strlen(line) - 1;
		while (c > line && (*c == '\n' || isspace(*c)))
			*c-- = '\0';

		if (parse_section_line(line, &current_section) == PARSED_OK) {
			if (current_section == PORT_SECTION) {
				char port[17];
				if (1 != sscanf(line, " %16s", port)) {
					fprintf(stderr, "could not parse port name on line %d\n",
							line_num);
					goto parse_error;
				}
				current_port = config_create_interface(port, cfg);
				if (!current_port)
					goto parse_error;
				config_init_interface(current_port, cfg);
			}
			continue;
		}

		switch (current_section) {
		case GLOBAL_SECTION:
		case PORT_SECTION:
			if (parse_setting_line(line, &option, &value)) {
				fprintf(stderr, "could not parse line %d in %s section\n",
						line_num,
						current_section == GLOBAL_SECTION ?
							"global" : current_port->name);
				goto parse_error;
			}

			check_deprecated_options(&option);

			if (current_section == GLOBAL_SECTION)
				parser_res = parse_global_setting(option, value, cfg);
			else
				parser_res = parse_port_setting(cfg, option, value, current_port);

			switch (parser_res) {
			case PARSED_OK:
				break;
			case NOT_PARSED:
				fprintf(stderr, "unknown option %s at line %d in %s section\n",
						option, line_num,
						current_section == GLOBAL_SECTION ?
							"global" : current_port->name);
				goto parse_error;
			case BAD_VALUE:
				fprintf(stderr, "%s is a bad value for option %s at line %d\n",
						value, option, line_num);
				goto parse_error;
			case MALFORMED:
				fprintf(stderr, "%s is a malformed value for option %s at line %d\n",
						value, option, line_num);
				goto parse_error;
			case OUT_OF_RANGE:
				fprintf(stderr, "%s is an out of range value for option %s at line %d\n",
						value, option, line_num);
				goto parse_error;
			}

			break;
		case UNKNOWN_SECTION:
			fprintf(stderr, "line %d is not in a section\n", line_num);
			goto parse_error;
		default:
			continue;
		}
	}

	fclose(fp);
	return 0;

parse_error:
	fprintf(stderr, "failed to parse configuration file %s\n", name);
	fclose(fp);
	return -2;
}

struct interface *config_create_interface(char *name, struct config *cfg)
{
	struct interface *iface;

	/* only create each interface once (by name) */
	STAILQ_FOREACH(iface, &cfg->interfaces, list) {
		if (0 == strncmp(name, iface->name, MAX_IFNAME_SIZE))
			return iface;
	}

	iface = calloc(1, sizeof(struct interface));
	if (!iface) {
		fprintf(stderr, "cannot allocate memory for a port\n");
		return NULL;
	}

	strncpy(iface->name, name, MAX_IFNAME_SIZE);
	STAILQ_INSERT_TAIL(&cfg->interfaces, iface, list);
	return iface;
}

void config_init_interface(struct interface *iface, struct config *cfg)
{
	iface->dm = cfg->dm;
	iface->transport = cfg->transport;
	memcpy(&iface->pod, &cfg->pod, sizeof(cfg->pod));

	sk_get_ts_info(iface->name, &iface->ts_info);

	iface->delay_filter = cfg->dds.delay_filter;
	iface->delay_filter_length = cfg->dds.delay_filter_length;
	iface->boundary_clock_jbod = cfg->dds.boundary_clock_jbod;
}

int config_init(struct config *cfg)
{
	char buf[CONFIG_LABEL_SIZE + 8];
	struct config_item *ci;
	int i;

	cfg->htab = hash_create();
	if (!cfg->htab) {
		return -1;
	}

	/* Populate the hash table with global defaults. */
	for (i = 0; i < N_CONFIG_ITEMS; i++) {
		ci = &config_tab[i];
		ci->flags |= CFG_ITEM_STATIC;
		snprintf(buf, sizeof(buf), "global.%s", ci->label);
		if (hash_insert(cfg->htab, buf, ci)) {
			fprintf(stderr, "duplicate item %s\n", ci->label);
			goto fail;
		}
	}

	/* Perform a Built In Self Test.*/
	for (i = 0; i < N_CONFIG_ITEMS; i++) {
		ci = &config_tab[i];
		ci = config_global_item(cfg, ci->label);
		if (ci != &config_tab[i]) {
			fprintf(stderr, "config BIST failed at %s\n",
				config_tab[i].label);
			goto fail;
		}
	}
	return 0;
fail:
	hash_destroy(cfg->htab, NULL);
	return -1;
}

void config_destroy(struct config *cfg)
{
	struct interface *iface;

	while ((iface = STAILQ_FIRST(&cfg->interfaces))) {
		STAILQ_REMOVE_HEAD(&cfg->interfaces, list);
		free(iface);
	}
	hash_destroy(cfg->htab, config_item_free);
}

double config_get_double(struct config *cfg, const char *section,
			 const char *option)
{
	struct config_item *ci = config_find_item(cfg, section, option);

	if (!ci || ci->type != CFG_TYPE_DOUBLE) {
		pr_err("bug: config option %s missing or invalid!", option);
		exit(-1);
	}
	pr_debug("config item %s.%s is %f", section, option, ci->val.d);
	return ci->val.d;
}

int config_get_int(struct config *cfg, const char *section, const char *option)
{
	struct config_item *ci = config_find_item(cfg, section, option);

	if (!ci) {
		pr_err("bug: config option %s missing!", option);
		exit(-1);
	}
	switch (ci->type) {
	case CFG_TYPE_DOUBLE:
		pr_err("bug: config option %s type mismatch!", option);
		exit(-1);
	case CFG_TYPE_INT:
		break;
	}
	pr_debug("config item %s.%s is %d", section, option, ci->val.i);
	return ci->val.i;
}

int config_set_double(struct config *cfg, const char *option, double val)
{
	struct config_item *ci = config_find_item(cfg, NULL, option);

	if (!ci || ci->type != CFG_TYPE_DOUBLE) {
		pr_err("bug: config option %s missing or invalid!", option);
		return -1;
	}
	ci->flags |= CFG_ITEM_LOCKED;
	ci->val.d = val;
	pr_debug("locked item global.%s as %f", option, ci->val.d);
	return 0;
}

int config_set_section_int(struct config *cfg, const char *section,
			   const char *option, int val)
{
	struct config_item *cgi, *dst;

	cgi = config_find_item(cfg, NULL, option);
	if (!cgi) {
		pr_err("bug: config option %s missing!", option);
		return -1;
	}
	switch (cgi->type) {
	case CFG_TYPE_DOUBLE:
		pr_err("bug: config option %s type mismatch!", option);
		return -1;
	case CFG_TYPE_INT:
		break;
	}
	if (!section) {
		cgi->flags |= CFG_ITEM_LOCKED;
		cgi->val.i = val;
		pr_debug("locked item global.%s as %d", option, cgi->val.i);
		return 0;
	}
	/* Create or update this port specific item. */
	dst = config_section_item(cfg, section, option);
	if (!dst) {
		dst = config_item_alloc(cfg, section, option, cgi->type);
		if (!dst) {
			return -1;
		}
	}
	dst->val.i = val;
	pr_debug("section item %s.%s now %d", section, option, dst->val.i);
	return 0;
}