[tor-commits] [tor/master] Use getifaddrs, not connect+getsockname, to find our address
nickm at torproject.org
nickm at torproject.org
Wed Dec 28 21:40:28 UTC 2011
commit aa529f6c32f2103a5571f98047ee3bd2d5074330
Author: Nick Mathewson <nickm at torproject.org>
Date: Fri Dec 2 17:05:52 2011 -0500
Use getifaddrs, not connect+getsockname, to find our address
This resolves bug1827, and lets us avoid freaking people out.
Later, we can use it to get a complete list of our interfaces.
---
configure.in | 2 +
src/common/address.c | 143 +++++++++++++++++++++++++++++++++++++++++++++++++-
src/test/test_addr.c | 11 ++--
3 files changed, 149 insertions(+), 7 deletions(-)
diff --git a/configure.in b/configure.in
index 1f045f1..a2aa417 100644
--- a/configure.in
+++ b/configure.in
@@ -300,6 +300,7 @@ AC_CHECK_FUNCS(
flock \
ftime \
getaddrinfo \
+ getifaddrs \
getrlimit \
gettimeofday \
gmtime_r \
@@ -624,6 +625,7 @@ dnl These headers are not essential
AC_CHECK_HEADERS(
arpa/inet.h \
grp.h \
+ ifaddrs.h \
inttypes.h \
limits.h \
linux/types.h \
diff --git a/src/common/address.c b/src/common/address.c
index c533687..9ee5d61 100644
--- a/src/common/address.c
+++ b/src/common/address.c
@@ -13,10 +13,16 @@
#include "util.h"
#include "address.h"
#include "torlog.h"
+#include "container.h"
#ifdef MS_WINDOWS
#include <process.h>
#include <windows.h>
+#include <winsock2.h>
+/* For access to structs needed by GetAdaptersAddresses */
+#undef _WIN32_WINNT
+#define _WIN32_WINNT 0x0501
+#include <iphlpapi.h>
#endif
#ifdef HAVE_SYS_TIME_H
@@ -46,6 +52,9 @@
#ifdef HAVE_SYS_UN_H
#include <sys/un.h>
#endif
+#ifdef HAVE_IFADDRS_H
+#include <ifaddrs.h>
+#endif
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
@@ -1086,6 +1095,114 @@ tor_addr_port_lookup(const char *s, tor_addr_t *addr_out, uint16_t *port_out)
return -1;
}
+#ifdef MS_WINDOWS
+typedef ULONG (WINAPI *GetAdaptersAddresses_fn_t)(
+ ULONG, ULONG, PVOID, PIP_ADAPTER_ADDRESSES, PULONG);
+#endif
+
+/** Try to ask our network interfaces what addresses they are bound to.
+ * Return a new smartlist of tor_addr_t on success, and NULL on failure.
+ * (An empty smartlist indicates that we successfully learned that we have no
+ * addresses.) Log failure messages at <b>severity</b>. */
+static smartlist_t *
+get_interface_addresses_raw(int severity)
+{
+#if defined(HAVE_GETIFADDRS)
+ /* Most free Unixy systems provide getifaddrs, which gives us a linked list
+ * of struct ifaddrs. */
+ struct ifaddrs *ifa = NULL;
+ const struct ifaddrs *i;
+ smartlist_t *result;
+ if (getifaddrs(&ifa) < 0) {
+ log_fn(severity, LD_NET, "Unable to call getifaddrs(): %s",
+ strerror(errno));
+ return NULL;
+ }
+
+ result = smartlist_create();
+ for (i = ifa; i; i = i->ifa_next) {
+ tor_addr_t tmp;
+ if (!i->ifa_addr)
+ continue;
+ if (i->ifa_addr->sa_family != AF_INET &&
+ i->ifa_addr->sa_family != AF_INET6)
+ continue;
+ if (tor_addr_from_sockaddr(&tmp, i->ifa_addr, NULL) < 0)
+ continue;
+ smartlist_add(result, tor_memdup(&tmp, sizeof(tmp)));
+ }
+
+ freeifaddrs(ifa);
+ return result;
+#elif defined(MS_WINDOWS)
+ /* Windows XP began to provide GetAdaptersAddresses. Windows 2000 had a
+ "GetAdaptersInfo", but that's deprecated; let's just try
+ GetAdaptersAddresses and fall back to connect+getsockname.
+ */
+ HANDLE lib = load_windows_system_library(TEXT("iphlpapi.dll"));
+ smartlist_t *result = NULL;
+ GetAdaptersAddresses_fn_t fn;
+ ULONG size, res;
+ IP_ADAPTER_ADDRESSES *addresses = NULL, *address;
+
+ (void) severity;
+
+#define FLAGS (GAA_FLAG_SKIP_ANYCAST | \
+ GAA_FLAG_SKIP_MULTICAST | \
+ GAA_FLAG_SKIP_DNS_SERVER)
+
+ if (!lib) {
+ log_fn(severity, LD_NET, "Unable to load iphlpapi.dll");
+ goto done;
+ }
+
+ if (!(fn = (GetAdaptersAddresses_fn_t)
+ GetProcAddress(lib, "GetAdaptersAddresses"))) {
+ log_fn(severity, LD_NET, "Unable to obtain pointer to "
+ "GetAdaptersAddresses");
+ goto done;
+ }
+
+ /* Guess how much space we need. */
+ size = 15*1024;
+ addresses = tor_malloc(size);
+ res = fn(AF_UNSPEC, FLAGS, NULL, addresses, &size);
+ if (res == ERROR_BUFFER_OVERFLOW) {
+ /* we didn't guess that we needed enough space; try again */
+ tor_free(addresses);
+ addresses = tor_malloc(size);
+ res = fn(AF_UNSPEC, FLAGS, NULL, addresses, &size);
+ }
+ if (res != NO_ERROR) {
+ log_fn(severity, LD_NET, "GetAdaptersAddresses failed (result: %lu)", res);
+ goto done;
+ }
+
+ result = smartlist_create();
+ for (address = addresses; address; address = address->Next) {
+ IP_ADAPTER_UNICAST_ADDRESS *a;
+ for (a = address->FirstUnicastAddress; a; a = a->Next) {
+ /* Yes, it's a linked list inside a linked list */
+ struct sockaddr *sa = a->Address.lpSockaddr;
+ tor_addr_t tmp;
+ if (sa->sa_family != AF_INET && sa->sa_family != AF_INET6)
+ continue;
+ if (tor_addr_from_sockaddr(&tmp, sa, NULL) < 0)
+ continue;
+ smartlist_add(result, tor_memdup(&tmp, sizeof(tmp)));
+ }
+ }
+
+ done:
+ if (lib)
+ FreeLibrary(lib);
+ tor_free(addresses);
+ return result;
+#else
+ (void) severity;
+ return NULL;
+#endif
+}
/** Set *<b>addr</b> to the IP address (if any) of whatever interface
* connects to the Internet. This address should only be used in checking
* whether our address has changed. Return 0 on success, -1 on failure.
@@ -1093,12 +1210,36 @@ tor_addr_port_lookup(const char *s, tor_addr_t *addr_out, uint16_t *port_out)
int
get_interface_address6(int severity, sa_family_t family, tor_addr_t *addr)
{
+ /* XXX really, this function should yield a smartlist of addresses. */
+ smartlist_t *addrs;
int sock=-1, r=-1;
struct sockaddr_storage my_addr, target_addr;
socklen_t addr_len;
-
tor_assert(addr);
+ /* Try to do this the smart way if possible. */
+ if ((addrs = get_interface_addresses_raw(severity))) {
+ int rv = -1;
+ SMARTLIST_FOREACH_BEGIN(addrs, tor_addr_t *, a) {
+ if (family != AF_UNSPEC && family != tor_addr_family(a))
+ continue;
+ if (tor_addr_is_loopback(a))
+ continue;
+ tor_addr_copy(addr, a);
+ rv = 0;
+
+ /* If we found a non-internal address, declare success. Otherwise,
+ * keep looking. */
+ if (!tor_addr_is_internal(a, 0))
+ break;
+ } SMARTLIST_FOREACH_END(a);
+
+ SMARTLIST_FOREACH(addrs, tor_addr_t *, a, tor_free(a));
+ smartlist_free(addrs);
+ return rv;
+ }
+
+ /* Okay, the smart way is out. */
memset(addr, 0, sizeof(tor_addr_t));
memset(&target_addr, 0, sizeof(target_addr));
/* Don't worry: no packets are sent. We just need to use a real address
diff --git a/src/test/test_addr.c b/src/test/test_addr.c
index 9d8e1fe..cf9c8f9 100644
--- a/src/test/test_addr.c
+++ b/src/test/test_addr.c
@@ -613,12 +613,11 @@ test_addr_ip6_helpers(void)
/* get interface addresses */
r = get_interface_address6(LOG_DEBUG, AF_INET, &t1);
i = get_interface_address6(LOG_DEBUG, AF_INET6, &t2);
-#if 0
- tor_inet_ntop(AF_INET, &t1.sa.sin_addr, buf, sizeof(buf));
- printf("\nv4 address: %s (family=%d)", buf, IN_FAMILY(&t1));
- tor_inet_ntop(AF_INET6, &t2.sa6.sin6_addr, buf, sizeof(buf));
- printf("\nv6 address: %s (family=%d)", buf, IN_FAMILY(&t2));
-#endif
+
+ TT_BLATHER(("v4 address: %s (family=%d)", fmt_addr(&t1),
+ tor_addr_family(&t1)));
+ TT_BLATHER(("v6 address: %s (family=%d)", fmt_addr(&t2),
+ tor_addr_family(&t2)));
done:
;
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