miniupnp/miniupnpd/getifaddr.c

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/* $Id: getifaddr.c,v 1.26 2019/05/20 19:54:08 nanard Exp $ */
/* vim: tabstop=4 shiftwidth=4 noexpandtab
* MiniUPnP project
* http://miniupnp.free.fr/ or https://miniupnp.tuxfamily.org/
* (c) 2006-2019 Thomas Bernard
* This software is subject to the conditions detailed
* in the LICENCE file provided within the distribution */
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#if defined(sun)
#include <sys/sockio.h>
#endif
#include "config.h"
#include "getifaddr.h"
#if defined(USE_GETIFADDRS) || defined(ENABLE_IPV6) || defined(ENABLE_PCP)
#include <ifaddrs.h>
#endif
int
getifaddr(const char * ifname, char * buf, int len,
struct in_addr * addr, struct in_addr * mask)
{
#ifndef USE_GETIFADDRS
/* use ioctl SIOCGIFADDR. Works only for ip v4 */
/* SIOCGIFADDR struct ifreq * */
int s;
struct ifreq ifr;
int ifrlen;
struct sockaddr_in * ifaddr;
ifrlen = sizeof(ifr);
if(!ifname || ifname[0]=='\0')
return -1;
s = socket(PF_INET, SOCK_DGRAM, 0);
if(s < 0)
{
syslog(LOG_ERR, "socket(PF_INET, SOCK_DGRAM): %m");
return -1;
}
strncpy(ifr.ifr_name, ifname, IFNAMSIZ-1);
ifr.ifr_name[IFNAMSIZ-1] = '\0';
if(ioctl(s, SIOCGIFFLAGS, &ifr, &ifrlen) < 0)
{
syslog(LOG_DEBUG, "ioctl(s, SIOCGIFFLAGS, ...): %m");
close(s);
return -1;
}
if ((ifr.ifr_flags & IFF_UP) == 0)
{
syslog(LOG_DEBUG, "network interface %s is down", ifname);
close(s);
return -1;
}
strncpy(ifr.ifr_name, ifname, IFNAMSIZ-1);
ifr.ifr_name[IFNAMSIZ-1] = '\0';
if(ioctl(s, SIOCGIFADDR, &ifr, &ifrlen) < 0)
{
syslog(LOG_ERR, "ioctl(s, SIOCGIFADDR, ...): %m");
close(s);
return -1;
}
ifaddr = (struct sockaddr_in *)&ifr.ifr_addr;
if(addr) *addr = ifaddr->sin_addr;
if(buf)
{
if(!inet_ntop(AF_INET, &ifaddr->sin_addr, buf, len))
{
syslog(LOG_ERR, "inet_ntop(): %m");
close(s);
return -1;
}
}
if(mask)
{
strncpy(ifr.ifr_name, ifname, IFNAMSIZ-1);
ifr.ifr_name[IFNAMSIZ-1] = '\0';
if(ioctl(s, SIOCGIFNETMASK, &ifr, &ifrlen) < 0)
{
syslog(LOG_ERR, "ioctl(s, SIOCGIFNETMASK, ...): %m");
close(s);
return -1;
}
#ifdef ifr_netmask
*mask = ((struct sockaddr_in *)&ifr.ifr_netmask)->sin_addr;
#else
*mask = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr;
#endif
}
close(s);
#else /* ifndef USE_GETIFADDRS */
/* Works for all address families (both ip v4 and ip v6) */
struct ifaddrs * ifap;
struct ifaddrs * ife;
if(!ifname || ifname[0]=='\0')
return -1;
if(getifaddrs(&ifap)<0)
{
syslog(LOG_ERR, "getifaddrs: %m");
return -1;
}
for(ife = ifap; ife; ife = ife->ifa_next)
{
/* skip other interfaces if one was specified */
if(ifname && (0 != strcmp(ifname, ife->ifa_name)))
continue;
if(ife->ifa_addr == NULL)
continue;
switch(ife->ifa_addr->sa_family)
{
case AF_INET:
if(buf)
{
inet_ntop(ife->ifa_addr->sa_family,
&((struct sockaddr_in *)ife->ifa_addr)->sin_addr,
buf, len);
}
if(addr) *addr = ((struct sockaddr_in *)ife->ifa_addr)->sin_addr;
if(mask) *mask = ((struct sockaddr_in *)ife->ifa_netmask)->sin_addr;
break;
/*
case AF_INET6:
inet_ntop(ife->ifa_addr->sa_family,
&((struct sockaddr_in6 *)ife->ifa_addr)->sin6_addr,
buf, len);
*/
}
}
freeifaddrs(ifap);
#endif
return 0;
}
#ifdef ENABLE_PCP
int getifaddr_in6(const char * ifname, int af, struct in6_addr * addr)
{
#if defined(ENABLE_IPV6) || defined(USE_GETIFADDRS)
struct ifaddrs * ifap;
struct ifaddrs * ife;
#ifdef ENABLE_IPV6
const struct sockaddr_in6 * tmpaddr;
#endif /* ENABLE_IPV6 */
int found = 0;
if(!ifname || ifname[0]=='\0')
return -1;
if(getifaddrs(&ifap)<0)
{
syslog(LOG_ERR, "getifaddrs: %m");
return -1;
}
for(ife = ifap; ife && !found; ife = ife->ifa_next)
{
/* skip other interfaces if one was specified */
if(ifname && (0 != strcmp(ifname, ife->ifa_name)))
continue;
if(ife->ifa_addr == NULL)
continue;
if (ife->ifa_addr->sa_family != af)
continue;
switch(ife->ifa_addr->sa_family)
{
case AF_INET:
/* IPv4-mapped IPv6 address ::ffff:1.2.3.4 */
memset(addr->s6_addr, 0, 10);
addr->s6_addr[10] = 0xff;
addr->s6_addr[11] = 0xff;
memcpy(addr->s6_addr + 12,
&(((struct sockaddr_in *)ife->ifa_addr)->sin_addr.s_addr),
4);
found = 1;
break;
#ifdef ENABLE_IPV6
case AF_INET6:
tmpaddr = (const struct sockaddr_in6 *)ife->ifa_addr;
if(!IN6_IS_ADDR_LOOPBACK(&tmpaddr->sin6_addr)
&& !IN6_IS_ADDR_LINKLOCAL(&tmpaddr->sin6_addr))
{
memcpy(addr->s6_addr,
&tmpaddr->sin6_addr,
16);
found = 1;
}
break;
#endif /* ENABLE_IPV6 */
}
}
freeifaddrs(ifap);
return (found ? 0 : -1);
#else /* defined(ENABLE_IPV6) || defined(USE_GETIFADDRS) */
/* IPv4 only */
struct in_addr addr4;
if(af != AF_INET)
return -1;
if(getifaddr(ifname, NULL, 0, &addr4, NULL) < 0)
return -1;
/* IPv4-mapped IPv6 address ::ffff:1.2.3.4 */
memset(addr->s6_addr, 0, 10);
addr->s6_addr[10] = 0xff;
addr->s6_addr[11] = 0xff;
memcpy(addr->s6_addr + 12, &addr4.s_addr, 4);
return 0;
#endif
}
#endif /* ENABLE_PCP */
#ifdef ENABLE_IPV6
int
find_ipv6_addr(const char * ifname,
char * dst, int n)
{
struct ifaddrs * ifap;
struct ifaddrs * ife;
const struct sockaddr_in6 * addr;
char buf[64];
int r = 0;
if(!dst)
return -1;
if(getifaddrs(&ifap)<0)
{
syslog(LOG_ERR, "getifaddrs: %m");
return -1;
}
for(ife = ifap; ife; ife = ife->ifa_next)
{
/* skip other interfaces if one was specified */
if(ifname && (0 != strcmp(ifname, ife->ifa_name)))
continue;
if(ife->ifa_addr == NULL)
continue;
if(ife->ifa_addr->sa_family == AF_INET6)
{
addr = (const struct sockaddr_in6 *)ife->ifa_addr;
if(!IN6_IS_ADDR_LOOPBACK(&addr->sin6_addr)
&& !IN6_IS_ADDR_LINKLOCAL(&addr->sin6_addr))
{
inet_ntop(ife->ifa_addr->sa_family,
&addr->sin6_addr,
buf, sizeof(buf));
/* add brackets */
snprintf(dst, n, "[%s]", buf);
r = 1;
}
}
}
freeifaddrs(ifap);
return r;
}
#endif
/* List of IP address blocks which are private / reserved and therefore not suitable for public external IP addresses */
/* If interface has IP address from one of this block, then it is either behind NAT or port forwarding is impossible */
#define IP(a, b, c, d) (((a) << 24) + ((b) << 16) + ((c) << 8) + (d))
#define MSK(m) (32-(m))
static const struct { uint32_t address; uint32_t rmask; } reserved[] = {
{ IP( 0, 0, 0, 0), MSK( 8) }, /* RFC1122 "This host on this network" */
{ IP( 10, 0, 0, 0), MSK( 8) }, /* RFC1918 Private-Use */
{ IP(100, 64, 0, 0), MSK(10) }, /* RFC6598 Shared Address Space */
{ IP(127, 0, 0, 0), MSK( 8) }, /* RFC1122 Loopback */
{ IP(169, 254, 0, 0), MSK(16) }, /* RFC3927 Link-Local */
{ IP(172, 16, 0, 0), MSK(12) }, /* RFC1918 Private-Use */
{ IP(192, 0, 0, 0), MSK(24) }, /* RFC6890 IETF Protocol Assignments */
{ IP(192, 0, 2, 0), MSK(24) }, /* RFC5737 Documentation (TEST-NET-1) */
{ IP(192, 31, 196, 0), MSK(24) }, /* RFC7535 AS112-v4 */
{ IP(192, 52, 193, 0), MSK(24) }, /* RFC7450 AMT */
{ IP(192, 88, 99, 0), MSK(24) }, /* RFC7526 6to4 Relay Anycast */
{ IP(192, 168, 0, 0), MSK(16) }, /* RFC1918 Private-Use */
{ IP(192, 175, 48, 0), MSK(24) }, /* RFC7534 Direct Delegation AS112 Service */
{ IP(198, 18, 0, 0), MSK(15) }, /* RFC2544 Benchmarking */
{ IP(198, 51, 100, 0), MSK(24) }, /* RFC5737 Documentation (TEST-NET-2) */
{ IP(203, 0, 113, 0), MSK(24) }, /* RFC5737 Documentation (TEST-NET-3) */
{ IP(224, 0, 0, 0), MSK( 4) }, /* RFC1112 Multicast */
{ IP(240, 0, 0, 0), MSK( 4) }, /* RFC1112 Reserved for Future Use + RFC919 Limited Broadcast */
};
#undef IP
#undef MSK
int
addr_is_reserved(struct in_addr * addr)
{
uint32_t address = ntohl(addr->s_addr);
size_t i;
for (i = 0; i < sizeof(reserved)/sizeof(reserved[0]); ++i) {
if ((address >> reserved[i].rmask) == (reserved[i].address >> reserved[i].rmask))
return 1;
}
return 0;
}