src/utils/common.c

/*
 * wpa_supplicant/hostapd / common helper functions, etc.
 * Copyright (c) 2002-2007, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "utils/includes.h"

#include "utils/common.h"
#include <time.h>

extern time_t mktime(struct tm*);

/**
 * inc_byte_array - Increment arbitrary length byte array by one
 * @counter: Pointer to byte array
 * @len: Length of the counter in bytes
 *
 * This function increments the last byte of the counter by one and continues
 * rolling over to more significant bytes if the byte was incremented from
 * 0xff to 0x00.
 */
void inc_byte_array(u8 *counter, size_t len)
{
	int pos = len - 1;
	while (pos >= 0) {
		counter[pos]++;
		if (counter[pos] != 0)
			break;
		pos--;
	}
}

static int hex2num(char c)
{
	if (c >= '0' && c <= '9')
		return c - '0';
	if (c >= 'a' && c <= 'f')
		return c - 'a' + 10;
	if (c >= 'A' && c <= 'F')
		return c - 'A' + 10;
	return -1;
}


int hex2byte(const char *hex)
{
	int a, b;
	a = hex2num(*hex++);
	if (a < 0)
		return -1;
	b = hex2num(*hex++);
	if (b < 0)
		return -1;
	return (a << 4) | b;
}


/**
 * hexstr2bin - Convert ASCII hex string into binary data
 * @hex: ASCII hex string (e.g., "01ab")
 * @buf: Buffer for the binary data
 * @len: Length of the text to convert in bytes (of buf); hex will be double
 * this size
 * Returns: 0 on success, -1 on failure (invalid hex string)
 */
int hexstr2bin(const char *hex, u8 *buf, size_t len)
{
	size_t i;
	int a;
	const char *ipos = hex;
	u8 *opos = buf;

	for (i = 0; i < len; i++) {
		a = hex2byte(ipos);
		if (a < 0)
			return -1;
		*opos++ = a;
		ipos += 2;
	}
	return 0;
}

void wpa_get_ntp_timestamp(u8 *buf)
{
	struct os_time now;
	u32 sec, usec;
	be32 tmp;

	/* 64-bit NTP timestamp (time from 1900-01-01 00:00:00) */
	os_get_time(&now);
	sec = now.sec + 2208988800U; /* Epoch to 1900 */
	/* Estimate 2^32/10^6 = 4295 - 1/32 - 1/512 */
	usec = now.usec;
	usec = 4295 * usec - (usec >> 5) - (usec >> 9);
	tmp = host_to_be32(sec);
	os_memcpy(buf, (u8 *) &tmp, 4);
	tmp = host_to_be32(usec);
	os_memcpy(buf + 4, (u8 *) &tmp, 4);
}
void printf_encode(char *txt, size_t maxlen, const u8 *data, size_t len)
{
	char *end = txt + maxlen;
	size_t i;

	for (i = 0; i < len; i++) {
		if (txt + 4 >= end)
			break;

		switch (data[i]) {
		case '\"':
			*txt++ = '\\';
			*txt++ = '\"';
			break;
		case '\\':
			*txt++ = '\\';
			*txt++ = '\\';
			break;
		case '\033':
			*txt++ = '\\';
			*txt++ = 'e';
			break;
		case '\n':
			*txt++ = '\\';
			*txt++ = 'n';
			break;
		case '\r':
			*txt++ = '\\';
			*txt++ = 'r';
			break;
		case '\t':
			*txt++ = '\\';
			*txt++ = 't';
			break;
		default:
			if (data[i] >= 32 && data[i] <= 127) {
				*txt++ = data[i];
			} else {
				txt += os_snprintf(txt, end - txt, "\\x%02x",
						   data[i]);
			}
			break;
		}
	}

	*txt = '\0';
}


size_t printf_decode(u8 *buf, size_t maxlen, const char *str)
{
	const char *pos = str;
	size_t len = 0;
	int val;

	while (*pos) {
		if (len + 1 >= maxlen)
			break;
		switch (*pos) {
		case '\\':
			pos++;
			switch (*pos) {
			case '\\':
				buf[len++] = '\\';
				pos++;
				break;
			case '"':
				buf[len++] = '"';
				pos++;
				break;
			case 'n':
				buf[len++] = '\n';
				pos++;
				break;
			case 'r':
				buf[len++] = '\r';
				pos++;
				break;
			case 't':
				buf[len++] = '\t';
				pos++;
				break;
			case 'e':
				buf[len++] = '\033';
				pos++;
				break;
			case 'x':
				pos++;
				val = hex2byte(pos);
				if (val < 0) {
					val = hex2num(*pos);
					if (val < 0)
						break;
					buf[len++] = val;
					pos++;
				} else {
					buf[len++] = val;
					pos += 2;
				}
				break;
			case '0':
			case '1':
			case '2':
			case '3':
			case '4':
			case '5':
			case '6':
			case '7':
				val = *pos++ - '0';
				if (*pos >= '0' && *pos <= '7')
					val = val * 8 + (*pos++ - '0');
				if (*pos >= '0' && *pos <= '7')
					val = val * 8 + (*pos++ - '0');
				buf[len++] = val;
				break;
			default:
				break;
			}
			break;
		default:
			buf[len++] = *pos++;
			break;
		}
	}
	if (maxlen > len)
		buf[len] = '\0';

	return len;
}


char * wpa_config_parse_string(const char *value, size_t *len)
{
	if (*value == '"') {
		const char *pos;
		char *str;
		value++;
		pos = os_strrchr(value, '"');
		if (pos == NULL || pos[1] != '\0')
			return NULL;
		*len = pos - value;
		str = dup_binstr(value, *len);
		if (str == NULL)
			return NULL;
		return str;
	} else if (*value == 'P' && value[1] == '"') {
		const char *pos;
		char *tstr, *str;
		size_t tlen;
		value += 2;
		pos = os_strrchr(value, '"');
		if (pos == NULL || pos[1] != '\0')
			return NULL;
		tlen = pos - value;
		tstr = dup_binstr(value, tlen);
		if (tstr == NULL)
			return NULL;

		str = os_malloc(tlen + 1);
		if (str == NULL) {
			os_free(tstr);
			return NULL;
		}

		*len = printf_decode((u8 *) str, tlen + 1, tstr);
		os_free(tstr);

		return str;
	} else {
		u8 *str;
		size_t tlen, hlen = os_strlen(value);
#ifndef ESP_SUPPLICANT
		if (hlen & 1)
			return NULL;
#else
		if (hlen == 5 || hlen == 13) {
			*len = hlen;
			str = (u8 *)os_malloc(*len + 1);
			if (str == NULL) {
				return NULL;
			}
			memcpy(str, value, *len);
			str[*len] = '\0';
			return (char *) str;
	        }
#endif
		tlen = hlen / 2;
		str = os_malloc(tlen + 1);
		if (str == NULL)
			return NULL;
		if (hexstr2bin(value, str, tlen)) {
			os_free(str);
			return NULL;
		}
		str[tlen] = '\0';
		*len = tlen;
		return (char *) str;
	}
}


int wpa_is_hex(const u8 *data, size_t len)
{
	size_t i;

	for (i = 0; i < len; i++) {
		if (data[i] < 32 || data[i] >= 127)
			return 1;
	}
	return 0;
}


size_t wpa_merge_byte_arrays(u8 *res, size_t res_len,
			 const u8 *src1, size_t src1_len,
			 const u8 *src2, size_t src2_len)
{
	size_t len = 0;

	os_memset(res, 0, res_len);

	if (src1) {
		if (src1_len >= res_len) {
			os_memcpy(res, src1, res_len);
			return res_len;
		}

		os_memcpy(res, src1, src1_len);
		len += src1_len;
	}

	if (src2) {
		if (len + src2_len >= res_len) {
			os_memcpy(res + len, src2, res_len - len);
			return res_len;
		}

		os_memcpy(res + len, src2, src2_len);
		len += src2_len;
	}

	return len;
}


char * dup_binstr(const void *src, size_t len)
{
	char *res;

	if (src == NULL)
		return NULL;
	res = os_malloc(len + 1);
	if (res == NULL)
		return NULL;
	os_memcpy(res, src, len);
	res[len] = '\0';

	return res;
}
void wpa_bin_clear_free(void *bin, size_t len)
{
	if (bin) {
		os_memset(bin, 0, len);
		os_free(bin);
	}
}

int int_array_len(const int *a)
{
	int i;
	for (i = 0; a && a[i]; i++)
		;
	return i;
}

void bin_clear_free(void *bin, size_t len)
{
	if (bin) {
		os_memset(bin, 0, len);
		os_free(bin);
	}
}

void str_clear_free(char *str)
{
	if (str) {
		size_t len = os_strlen(str);
		os_memset(str, 0, len);
		os_free(str);
	}
}

int os_gmtime(os_time_t t, struct os_tm *tm)
{
	struct tm *tm2;
	time_t t2 = t;

	tm2 = gmtime(&t2);
	if (tm2 == NULL)
		return -1;
	tm->sec = tm2->tm_sec;
	tm->min = tm2->tm_min;
	tm->hour = tm2->tm_hour;
	tm->day = tm2->tm_mday;
	tm->month = tm2->tm_mon + 1;
	tm->year = tm2->tm_year + 1900;
	return 0;
}

int os_mktime(int year, int month, int day, int hour, int min, int sec,
		os_time_t *t)
{
	struct tm tm;

	if (year < 1970 || month < 1 || month > 12 || day < 1 || day > 31 ||
			hour < 0 || hour > 23 || min < 0 || min > 59 || sec < 0 ||
			sec > 60)
		return -1;

	os_memset(&tm, 0, sizeof(tm));
	tm.tm_year = year - 1900;
	tm.tm_mon = month - 1;
	tm.tm_mday = day;
	tm.tm_hour = hour;
	tm.tm_min = min;
	tm.tm_sec = sec;

	*t = (os_time_t) mktime(&tm);
	return 0;
}

char * get_param(const char *cmd, const char *param)
{
	const char *pos, *end;
	char *val;
	size_t len;

	pos = os_strstr(cmd, param);
	if (!pos)
		return NULL;

	pos += os_strlen(param);
	end = os_strchr(pos, ' ');
	if (end)
		len = end - pos;
	else
		len = os_strlen(pos);
	val = os_malloc(len + 1);
	if (!val)
		return NULL;
	os_memcpy(val, pos, len);
	val[len] = '\0';
	return val;
}

void * os_memdup(const void *src, size_t len)
{
	void *r = os_malloc(len);

	if (r && src)
		os_memcpy(r, src, len);
	return r;
}

/**
 * hwaddr_aton2 - Convert ASCII string to MAC address (in any known format)
 * @txt: MAC address as a string (e.g., 00:11:22:33:44:55 or 0011.2233.4455)
 * @addr: Buffer for the MAC address (ETH_ALEN = 6 bytes)
 * Returns: Characters used (> 0) on success, -1 on failure
 */
int hwaddr_aton2(const char *txt, u8 *addr)
{
	int i;
	const char *pos = txt;

	for (i = 0; i < 6; i++) {
		int a, b;

		while (*pos == ':' || *pos == '.' || *pos == '-')
			pos++;

		a = hex2num(*pos++);
		if (a < 0)
			return -1;
		b = hex2num(*pos++);
		if (b < 0)
			return -1;
		*addr++ = (a << 4) | b;
	}

	return pos - txt;
}

static inline int os_reltime_expired(struct os_time *now,
				     struct os_time *ts,
				     os_time_t timeout_secs)
{
	struct os_time age;

	os_time_sub(now, ts, &age);
	return (age.sec > timeout_secs) ||
		(age.sec == timeout_secs && age.usec > 0);
}

int os_time_expired(struct os_time *now,
		struct os_time *ts,
		os_time_t timeout_secs)
{
	return os_reltime_expired(now, ts, timeout_secs);
}

u8 rssi_to_rcpi(int rssi)
{
	if (!rssi)
		return 255; /* not available */
	if (rssi < -110)
		return 0;
	if (rssi > 0)
		return 220;
	return (rssi + 110) * 2;
}

/**
 * wpa_ssid_txt - Convert SSID to a printable string
 * @ssid: SSID (32-octet string)
 * @ssid_len: Length of ssid in octets
 * Returns: Pointer to a printable string
 *
 * This function can be used to convert SSIDs into printable form. In most
 * cases, SSIDs do not use unprintable characters, but IEEE 802.11 standard
 * does not limit the used character set, so anything could be used in an SSID.
 *
 * This function uses a static buffer, so only one call can be used at the
 * time, i.e., this is not re-entrant and the returned buffer must be used
 * before calling this again.
 */
const char * wpa_ssid_txt(const u8 *ssid, size_t ssid_len)
{
	static char ssid_txt[SSID_MAX_LEN * 4 + 1];

	if (ssid == NULL) {
		ssid_txt[0] = '\0';
		return ssid_txt;
	}

	printf_encode(ssid_txt, sizeof(ssid_txt), ssid, ssid_len);
	return ssid_txt;
}