#define _GNU_SOURCE

#include "helpers.h"
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <ifaddrs.h>
#include <time.h>
#include <sys/stat.h>

char *strncasestr(const char *s, const char *find, size_t slen)
{
	char c, sc;
	size_t len;

	if ((c = *find++) != '\0')
	{
		len = strlen(find);
		do
		{
			do
			{
				if (slen-- < 1 || (sc = *s++) == '\0')
					return NULL;
			} while (toupper(c) != toupper(sc));
			if (len > slen)
				return NULL;
		} while (strncasecmp(s, find, len) != 0);
		s--;
	}
	return (char *)s;
}

bool append_to_list_file(const char *filename, const char *s)
{
	FILE *F = fopen(filename, "at");
	if (!F)
		return false;
	bool bOK = fprintf(F, "%s\n", s) > 0;
	fclose(F);
	return bOK;
}

void ntop46(const struct sockaddr *sa, char *str, size_t len)
{
	if (!len)
		return;
	*str = 0;
	switch (sa->sa_family)
	{
	case AF_INET:
		inet_ntop(sa->sa_family, &((struct sockaddr_in *)sa)->sin_addr, str, len);
		break;
	case AF_INET6:
		inet_ntop(sa->sa_family, &((struct sockaddr_in6 *)sa)->sin6_addr, str, len);
		break;
	default:
		snprintf(str, len, "UNKNOWN_FAMILY_%d", sa->sa_family);
	}
}
void ntop46_port(const struct sockaddr *sa, char *str, size_t len)
{
	char ip[40];
	ntop46(sa, ip, sizeof(ip));
	switch (sa->sa_family)
	{
	case AF_INET:
		snprintf(str, len, "%s:%u", ip, ntohs(((struct sockaddr_in *)sa)->sin_port));
		break;
	case AF_INET6:
		snprintf(str, len, "[%s]:%u", ip, ntohs(((struct sockaddr_in6 *)sa)->sin6_port));
		break;
	default:
		snprintf(str, len, "%s", ip);
	}
}
void print_sockaddr(const struct sockaddr *sa)
{
	char ip_port[48];

	ntop46_port(sa, ip_port, sizeof(ip_port));
	printf("%s", ip_port);
}

// -1 = error,  0 = not local, 1 = local
bool check_local_ip(const struct sockaddr *saddr)
{
	struct ifaddrs *addrs, *a;

	if (is_localnet(saddr))
		return true;

	if (getifaddrs(&addrs) < 0)
		return false;
	a = addrs;

	bool bres = false;
	while (a)
	{
		if (a->ifa_addr && sacmp(a->ifa_addr, saddr))
		{
			bres = true;
			break;
		}
		a = a->ifa_next;
	}

	freeifaddrs(addrs);
	return bres;
}
void print_addrinfo(const struct addrinfo *ai)
{
	char str[64];
	while (ai)
	{
		switch (ai->ai_family)
		{
		case AF_INET:
			if (inet_ntop(ai->ai_family, &((struct sockaddr_in *)ai->ai_addr)->sin_addr, str, sizeof(str)))
				printf("%s\n", str);
			break;
		case AF_INET6:
			if (inet_ntop(ai->ai_family, &((struct sockaddr_in6 *)ai->ai_addr)->sin6_addr, str, sizeof(str)))
				printf("%s\n", str);
			break;
		}
		ai = ai->ai_next;
	}
}

bool saismapped(const struct sockaddr_in6 *sa)
{
	// ::ffff:1.2.3.4
	return !memcmp(sa->sin6_addr.s6_addr, "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff", 12);
}
bool samappedcmp(const struct sockaddr_in *sa1, const struct sockaddr_in6 *sa2)
{
	return saismapped(sa2) && !memcmp(sa2->sin6_addr.s6_addr + 12, &sa1->sin_addr.s_addr, 4);
}
bool sacmp(const struct sockaddr *sa1, const struct sockaddr *sa2)
{
	return (sa1->sa_family == AF_INET && sa2->sa_family == AF_INET && !memcmp(&((struct sockaddr_in *)sa1)->sin_addr, &((struct sockaddr_in *)sa2)->sin_addr, sizeof(struct in_addr))) ||
		   (sa1->sa_family == AF_INET6 && sa2->sa_family == AF_INET6 && !memcmp(&((struct sockaddr_in6 *)sa1)->sin6_addr, &((struct sockaddr_in6 *)sa2)->sin6_addr, sizeof(struct in6_addr))) ||
		   (sa1->sa_family == AF_INET && sa2->sa_family == AF_INET6 && samappedcmp((struct sockaddr_in *)sa1, (struct sockaddr_in6 *)sa2)) ||
		   (sa1->sa_family == AF_INET6 && sa2->sa_family == AF_INET && samappedcmp((struct sockaddr_in *)sa2, (struct sockaddr_in6 *)sa1));
}
uint16_t saport(const struct sockaddr *sa)
{
	return htons(sa->sa_family == AF_INET ? ((struct sockaddr_in *)sa)->sin_port : sa->sa_family == AF_INET6 ? ((struct sockaddr_in6 *)sa)->sin6_port
																											 : 0);
}
bool saconvmapped(struct sockaddr_storage *a)
{
	if ((a->ss_family == AF_INET6) && saismapped((struct sockaddr_in6 *)a))
	{
		uint32_t ip4 = IN6_EXTRACT_MAP4(((struct sockaddr_in6 *)a)->sin6_addr.s6_addr);
		uint16_t port = ((struct sockaddr_in6 *)a)->sin6_port;
		a->ss_family = AF_INET;
		((struct sockaddr_in *)a)->sin_addr.s_addr = ip4;
		((struct sockaddr_in *)a)->sin_port = port;
		return true;
	}
	return false;
}

bool is_localnet(const struct sockaddr *a)
{
	// match 127.0.0.0/8, 0.0.0.0, ::1, ::0, :ffff:127.0.0.0/104, :ffff:0.0.0.0
	return (a->sa_family == AF_INET && (IN_LOOPBACK(ntohl(((struct sockaddr_in *)a)->sin_addr.s_addr)) ||
										INADDR_ANY == ntohl((((struct sockaddr_in *)a)->sin_addr.s_addr)))) ||
		   (a->sa_family == AF_INET6 && (IN6_IS_ADDR_LOOPBACK(&((struct sockaddr_in6 *)a)->sin6_addr) ||
										 IN6_IS_ADDR_UNSPECIFIED(&((struct sockaddr_in6 *)a)->sin6_addr) ||
										 (IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)a)->sin6_addr) && (IN_LOOPBACK(ntohl(IN6_EXTRACT_MAP4(((struct sockaddr_in6 *)a)->sin6_addr.s6_addr))) ||
																										   INADDR_ANY == ntohl(IN6_EXTRACT_MAP4(((struct sockaddr_in6 *)a)->sin6_addr.s6_addr))))));
}
bool is_linklocal(const struct sockaddr_in6 *a)
{
	// fe80::/10
	return a->sin6_addr.s6_addr[0] == 0xFE && (a->sin6_addr.s6_addr[1] & 0xC0) == 0x80;
}
bool is_private6(const struct sockaddr_in6 *a)
{
	// fc00::/7
	return (a->sin6_addr.s6_addr[0] & 0xFE) == 0xFC;
}

bool set_keepalive(int fd)
{
	int yes = 1;
	return setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &yes, sizeof(int)) != -1;
}
bool set_ttl(int fd, int ttl)
{
	return setsockopt(fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)) != -1;
}
bool set_hl(int fd, int hl)
{
	return setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &hl, sizeof(hl)) != -1;
}
bool set_ttl_hl(int fd, int ttl)
{
	bool b1, b2;
	// try to set both but one may fail if family is wrong
	b1 = set_ttl(fd, ttl);
	b2 = set_hl(fd, ttl);
	return b1 || b2;
}
int get_so_error(int fd)
{
	// getsockopt(SO_ERROR) clears error
	int errn;
	socklen_t optlen = sizeof(errn);
	if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &errn, &optlen) == -1)
		errn = errno;
	return errn;
}

int fprint_localtime(FILE *F)
{
	struct tm t;
	time_t now;

	time(&now);
	localtime_r(&now, &t);
	return fprintf(F, "%02d.%02d.%04d %02d:%02d:%02d", t.tm_mday, t.tm_mon + 1, t.tm_year + 1900, t.tm_hour, t.tm_min, t.tm_sec);
}

time_t file_mod_time(const char *filename)
{
	struct stat st;
	return stat(filename, &st) == -1 ? 0 : st.st_mtime;
}

bool pf_in_range(uint16_t port, const port_filter *pf)
{
	return port && (((!pf->from && !pf->to) || (port >= pf->from && port <= pf->to)) ^ pf->neg);
}
bool pf_parse(const char *s, port_filter *pf)
{
	unsigned int v1, v2;

	if (!s)
		return false;
	if (*s == '~')
	{
		pf->neg = true;
		s++;
	}
	else
		pf->neg = false;
	if (sscanf(s, "%u-%u", &v1, &v2) == 2)
	{
		if (!v1 || v1 > 65535 || v2 > 65535 || v1 > v2)
			return false;
		pf->from = (uint16_t)v1;
		pf->to = (uint16_t)v2;
	}
	else if (sscanf(s, "%u", &v1) == 1)
	{
		if (!v1 || v1 > 65535)
			return false;
		pf->to = pf->from = (uint16_t)v1;
	}
	else
		return false;
	return true;
}