tinc/src/netutl.c

/*
    netutl.c -- some supporting network utility code
    Copyright (C) 1998-2005 Ivo Timmermans
                  2000-2016 Guus Sliepen <guus@tinc-vpn.org>

    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 "system.h"

#include "net.h"
#include "netutl.h"
#include "logger.h"
#include "utils.h"
#include "xalloc.h"

bool hostnames = false;

/*
  Turn a string into a struct addrinfo.
  Return NULL on failure.
*/
struct addrinfo *str2addrinfo(const char *address, const char *service, int socktype) {
	struct addrinfo *ai = NULL, hint = {0};
	int err;

	hint.ai_family = addressfamily;
	hint.ai_socktype = socktype;

#if HAVE_DECL_RES_INIT
	// ensure glibc reloads /etc/resolv.conf.
	res_init();
#endif
	err = getaddrinfo(address, service, &hint, &ai);

	if(err) {
		logger(LOG_WARNING, "Error looking up %s port %s: %s", address,
				   service, gai_strerror(err));
		return NULL;
	}

	return ai;
}

sockaddr_t str2sockaddr(const char *address, const char *port) {
	struct addrinfo *ai = NULL, hint = {0};
	sockaddr_t result;
	int err;

	hint.ai_family = AF_UNSPEC;
	hint.ai_flags = AI_NUMERICHOST;
	hint.ai_socktype = SOCK_STREAM;

	err = getaddrinfo(address, port, &hint, &ai);

	if(err || !ai) {
		ifdebug(SCARY_THINGS)
			logger(LOG_DEBUG, "Unknown type address %s port %s", address, port);
		result.sa.sa_family = AF_UNKNOWN;
		result.unknown.address = xstrdup(address);
		result.unknown.port = xstrdup(port);
		return result;
	}

	memcpy(&result, ai->ai_addr, ai->ai_addrlen);
	freeaddrinfo(ai);

	return result;
}

void sockaddr2str(const sockaddr_t *sa, char **addrstr, char **portstr) {
	char address[NI_MAXHOST];
	char port[NI_MAXSERV];
	char *scopeid;
	int err;

	if(sa->sa.sa_family == AF_UNKNOWN) {
		if(addrstr)
			*addrstr = xstrdup(sa->unknown.address);
		if(portstr)
			*portstr = xstrdup(sa->unknown.port);
		return;
	}

	err = getnameinfo(&sa->sa, SALEN(sa->sa), address, sizeof(address), port, sizeof(port), NI_NUMERICHOST | NI_NUMERICSERV);

	if(err) {
		logger(LOG_ERR, "Error while translating addresses: %s",
			   gai_strerror(err));
		abort();
	}

	scopeid = strchr(address, '%');

	if(scopeid)
		*scopeid = '\0';		/* Descope. */

	if(addrstr)
		*addrstr = xstrdup(address);
	if(portstr)
		*portstr = xstrdup(port);
}

char *sockaddr2hostname(const sockaddr_t *sa) {
	char *str;
	char address[NI_MAXHOST] = "unknown";
	char port[NI_MAXSERV] = "unknown";
	int err;

	if(sa->sa.sa_family == AF_UNKNOWN) {
		xasprintf(&str, "%s port %s", sa->unknown.address, sa->unknown.port);
		return str;
	}

	err = getnameinfo(&sa->sa, SALEN(sa->sa), address, sizeof(address), port, sizeof(port),
					hostnames ? 0 : (NI_NUMERICHOST | NI_NUMERICSERV));
	if(err) {
		logger(LOG_ERR, "Error while looking up hostname: %s",
			   gai_strerror(err));
	}

	xasprintf(&str, "%s port %s", address, port);

	return str;
}

int sockaddrcmp_noport(const sockaddr_t *a, const sockaddr_t *b) {
	int result;

	result = a->sa.sa_family - b->sa.sa_family;

	if(result)
		return result;

	switch (a->sa.sa_family) {
		case AF_UNSPEC:
			return 0;

		case AF_UNKNOWN:
			return strcmp(a->unknown.address, b->unknown.address);

		case AF_INET:
			return memcmp(&a->in.sin_addr, &b->in.sin_addr, sizeof(a->in.sin_addr));

		case AF_INET6:
			return memcmp(&a->in6.sin6_addr, &b->in6.sin6_addr, sizeof(a->in6.sin6_addr));

		default:
			logger(LOG_ERR, "sockaddrcmp() was called with unknown address family %d, exitting!",
				   a->sa.sa_family);
			abort();
	}
}

int sockaddrcmp(const sockaddr_t *a, const sockaddr_t *b) {
	int result;

	result = a->sa.sa_family - b->sa.sa_family;

	if(result)
		return result;

	switch (a->sa.sa_family) {
		case AF_UNSPEC:
			return 0;

		case AF_UNKNOWN:
			result = strcmp(a->unknown.address, b->unknown.address);

			if(result)
				return result;

			return strcmp(a->unknown.port, b->unknown.port);

		case AF_INET:
			result = memcmp(&a->in.sin_addr, &b->in.sin_addr, sizeof(a->in.sin_addr));

			if(result)
				return result;

			return memcmp(&a->in.sin_port, &b->in.sin_port, sizeof(a->in.sin_port));

		case AF_INET6:
			result = memcmp(&a->in6.sin6_addr, &b->in6.sin6_addr, sizeof(a->in6.sin6_addr));

			if(result)
				return result;

			return memcmp(&a->in6.sin6_port, &b->in6.sin6_port, sizeof(a->in6.sin6_port));

		default:
			logger(LOG_ERR, "sockaddrcmp() was called with unknown address family %d, exitting!",
				   a->sa.sa_family);
			abort();
	}
}

void sockaddrcpy(sockaddr_t *a, const sockaddr_t *b) {
	if(b->sa.sa_family != AF_UNKNOWN) {
		*a = *b;
	} else {
		a->unknown.family = AF_UNKNOWN;
		a->unknown.address = xstrdup(b->unknown.address);
		a->unknown.port = xstrdup(b->unknown.port);
	}
}

void sockaddrfree(sockaddr_t *a) {
	if(a->sa.sa_family == AF_UNKNOWN) {
		free(a->unknown.address);
		free(a->unknown.port);
	}
}
	
void sockaddrunmap(sockaddr_t *sa) {
	if(sa->sa.sa_family == AF_INET6 && IN6_IS_ADDR_V4MAPPED(&sa->in6.sin6_addr)) {
		sa->in.sin_addr.s_addr = ((uint32_t *) & sa->in6.sin6_addr)[3];
		sa->in.sin_family = AF_INET;
	}
}

void sockaddr_setport(sockaddr_t *sa, const char *port) {
	uint16_t portnum = htons(atoi(port));
	if(!portnum)
		return;
	switch(sa->sa.sa_family) {
		case AF_INET:
			sa->in.sin_port = portnum;
			break;
		case AF_INET6:
			sa->in6.sin6_port = portnum;
			break;
		case AF_UNKNOWN:
			free(sa->unknown.port);
			sa->unknown.port = xstrdup(port);
		default:
			return;
	}
}

/* Subnet mask handling */

int maskcmp(const void *va, const void *vb, int masklen) {
	int i, m, result;
	const char *a = va;
	const char *b = vb;

	for(m = masklen, i = 0; m >= 8; m -= 8, i++) {
		result = a[i] - b[i];
		if(result)
			return result;
	}

	if(m)
		return (a[i] & (0x100 - (1 << (8 - m)))) -
			(b[i] & (0x100 - (1 << (8 - m))));

	return 0;
}

void mask(void *va, int masklen, int len) {
	int i;
	char *a = va;

	i = masklen / 8;
	masklen %= 8;

	if(masklen)
		a[i++] &= (0x100 - (1 << (8 - masklen)));

	for(; i < len; i++)
		a[i] = 0;
}

void maskcpy(void *va, const void *vb, int masklen, int len) {
	int i, m;
	char *a = va;
	const char *b = vb;

	for(m = masklen, i = 0; m >= 8; m -= 8, i++)
		a[i] = b[i];

	if(m) {
		a[i] = b[i] & (0x100 - (1 << (8 - m)));
		i++;
	}

	for(; i < len; i++)
		a[i] = 0;
}

bool maskcheck(const void *va, int masklen, int len) {
	int i;
	const char *a = va;

	i = masklen / 8;
	masklen %= 8;

	if(masklen && a[i++] & (0xff >> masklen))
		return false;

	for(; i < len; i++)
		if(a[i] != 0)
			return false;

	return true;
}