应用正则表达式判断IP/MAC/DNS合法性

/**
* 判断字符串是否满足正则表达式
* regex_pattern: 正则表达式
* to_match: 待匹配正则表达式的字符串
* 返回值: -1 不匹配
*          0 匹配
*/
int regex_exe(const char *regex_pattern, const char *to_match)
{
regex_t r;
int ret;
int match;
char errmsg[128];

if(regcomp(&r, regex_pattern, REG_EXTENDED | REG_NEWLINE)) {
printf("regcomp failed!\n");
regfree(&r);
return -1;
}

ret = regexec(&r, to_match, 0, NULL, 0);
if(!ret) {
match = 1;
printf("match!\n");
} else if(ret == REG_NOMATCH) {
match = 0;
printf("not match!\n");
} else {
regerror(ret, &r, errmsg, sizeof(errmsg));
printf("regexec failed: %s!\n", errmsg);
regfree(&r);
return -1;
}

regfree(&r);
return match;
}

int check_ip(const char *ip)
{
int match;
const char validIpAddress[] = "^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$";

match = regex_exe(validIpAddress, ip);
if(match != 1) {
return -1;
}

return 0;
}

int check_mac(const char *mac)
{
int match;
const char validMacAddress[] = "^([a-fA-F0-9]{2}:){5}([a-fA-F0-9]{2})$";

printf("%s\n", mac);
match = regex_exe(validMacAddress, mac);
if(match != 1) {
return -1;
}

return 0;
}

int check_dns(const char *dns)
{
int match;
const char validDnsRegex[] = "^(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\\-]*[a-zA-Z0-9])\\.)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\\-]*[A-Za-z0-9])$";

printf("%s\n", dns);
match = regex_exe(validDnsRegex, dns);
if(match != 1) {
return -1;
}

return 0;
}