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Diffstat (limited to 'sysdeps/posix/getaddrinfo.c')
-rw-r--r--sysdeps/posix/getaddrinfo.c378
1 files changed, 377 insertions, 1 deletions
diff --git a/sysdeps/posix/getaddrinfo.c b/sysdeps/posix/getaddrinfo.c
index 3b86b25122..4885a53118 100644
--- a/sysdeps/posix/getaddrinfo.c
+++ b/sysdeps/posix/getaddrinfo.c
@@ -53,6 +53,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include <sys/utsname.h>
#include <net/if.h>
#include <nsswitch.h>
+#include <not-cancel.h>
#define GAIH_OKIFUNSPEC 0x0100
#define GAIH_EAI ~(GAIH_OKIFUNSPEC)
@@ -894,11 +895,342 @@ static struct gaih gaih[] =
{ PF_UNSPEC, NULL }
};
+struct sort_result
+{
+ struct addrinfo *dest_addr;
+ struct sockaddr_storage source_addr;
+ bool got_source_addr;
+};
+
+
+static int
+get_scope (const struct sockaddr_storage *ss)
+{
+ int scope;
+ if (ss->ss_family == PF_INET6)
+ {
+ const struct sockaddr_in6 *in6 = (const struct sockaddr_in6 *) ss;
+
+ if (! IN6_IS_ADDR_MULTICAST (&in6->sin6_addr))
+ {
+ if (IN6_IS_ADDR_LINKLOCAL (&in6->sin6_addr))
+ scope = 2;
+ else if (IN6_IS_ADDR_SITELOCAL (&in6->sin6_addr))
+ scope = 5;
+ else
+ /* XXX Is this the correct default behavior? */
+ scope = 14;
+ }
+ else
+ scope = in6->sin6_addr.s6_addr[1] & 0xf;
+ }
+ else if (ss->ss_family == PF_INET)
+ {
+ const struct sockaddr_in *in = (const struct sockaddr_in *) ss;
+ const uint8_t *addr = (const uint8_t *) &in->sin_addr;
+
+ /* RFC 3484 specifies how to map IPv6 addresses to scopes.
+ 169.254/16 and 127/8 are link-local. */
+ if ((addr[0] == 169 && addr[1] == 254) || addr[0] == 127)
+ scope = 2;
+ else if (addr[0] == 10 || (addr[0] == 172 && addr[1] == 16)
+ || (addr[0] == 192 && addr[1] == 168))
+ scope = 5;
+ else
+ scope = 14;
+ }
+ else
+ /* XXX What is a good default? */
+ scope = 15;
+
+ return scope;
+}
+
+
+/* XXX The system administrator should be able to install other
+ tables. We need to make this configurable. The problem is that
+ the kernel is also involved since it needs the same table. */
+static const struct prefixlist
+{
+ struct in6_addr prefix;
+ unsigned int bits;
+ int val;
+} default_labels[] =
+ {
+ /* See RFC 3484 for the details. */
+ { { .in6_u = { .u6_addr16 = { 0x0000, 0x0000, 0x0000, 0x0000,
+ 0x0000, 0x0000, 0x0000, 0x0001 } } },
+ 128, 0 },
+ { { .in6_u = { .u6_addr16 = { 0x2002, 0x0000, 0x0000, 0x0000,
+ 0x0000, 0x0000, 0x0000, 0x0000 } } },
+ 16, 2 },
+ { { .in6_u = { .u6_addr16 = { 0x0000, 0x0000, 0x0000, 0x0000,
+ 0x0000, 0x0000, 0x0000, 0x0000 } } },
+ 96, 3 },
+ { { .in6_u = { .u6_addr16 = { 0x0000, 0x0000, 0x0000, 0x0000,
+ 0x0000, 0xffff, 0x0000, 0x0000 } } },
+ 96, 4 },
+ { { .in6_u = { .u6_addr16 = { 0x0000, 0x0000, 0x0000, 0x0000,
+ 0x0000, 0x0000, 0x0000, 0x0000 } } },
+ 0, 1 }
+ };
+
+
+static const struct prefixlist default_precedence[] =
+ {
+ /* See RFC 3484 for the details. */
+ { { .in6_u = { .u6_addr16 = { 0x0000, 0x0000, 0x0000, 0x0000,
+ 0x0000, 0x0000, 0x0000, 0x0001 } } },
+ 128, 50 },
+ { { .in6_u = { .u6_addr16 = { 0x2002, 0x0000, 0x0000, 0x0000,
+ 0x0000, 0x0000, 0x0000, 0x0000 } } },
+ 16, 30 },
+ { { .in6_u = { .u6_addr16 = { 0x0000, 0x0000, 0x0000, 0x0000,
+ 0x0000, 0x0000, 0x0000, 0x0000 } } },
+ 96, 20 },
+ { { .in6_u = { .u6_addr16 = { 0x0000, 0x0000, 0x0000, 0x0000,
+ 0x0000, 0xffff, 0x0000, 0x0000 } } },
+ 96, 10 },
+ { { .in6_u = { .u6_addr16 = { 0x0000, 0x0000, 0x0000, 0x0000,
+ 0x0000, 0x0000, 0x0000, 0x0000 } } },
+ 0, 40 }
+ };
+
+
+static int
+match_prefix (const struct sockaddr_storage *ss, const struct prefixlist *list,
+ int default_val)
+{
+ int idx;
+ struct sockaddr_in6 in6_mem;
+ const struct sockaddr_in6 *in6;
+
+ if (ss->ss_family == PF_INET6)
+ in6 = (const struct sockaddr_in6 *) ss;
+ else if (ss->ss_family == PF_INET)
+ {
+ const struct sockaddr_in *in = (const struct sockaddr_in *) ss;
+
+ /* Convert to IPv6 address. */
+ in6_mem.sin6_family = PF_INET6;
+ in6_mem.sin6_port = in->sin_port;
+ in6_mem.sin6_flowinfo = 0;
+ if (in->sin_addr.s_addr == htonl (0x7f000001))
+ in6_mem.sin6_addr = (struct in6_addr) IN6ADDR_LOOPBACK_INIT;
+ else
+ {
+ /* Construct a V4-to-6 mapped address. */
+ memset (&in6_mem.sin6_addr, '\0', sizeof (in6_mem.sin6_addr));
+ in6_mem.sin6_addr.s6_addr16[5] = 0xffff;
+ in6_mem.sin6_addr.s6_addr32[3] = in->sin_addr.s_addr;
+ in6_mem.sin6_scope_id = 0;
+ }
+
+ in6 = &in6_mem;
+ }
+ else
+ return default_val;
+
+ for (idx = 0; ; ++idx)
+ {
+ unsigned int bits = list[idx].bits;
+ uint8_t *mask = list[idx].prefix.s6_addr;
+ uint8_t *val = in6->sin6_addr.s6_addr;
+
+ while (bits > 8)
+ {
+ if (*mask != *val)
+ break;
+
+ ++mask;
+ ++val;
+ bits -= 8;
+ }
+
+ if (bits < 8)
+ {
+ if ((*mask & (0xff >> bits)) == (*val & (0xff >> bits)))
+ /* Match! */
+ break;
+ }
+ }
+
+ return list[idx].val;
+}
+
+
+static int
+get_label (const struct sockaddr_storage *ss)
+{
+ /* XXX What is a good default value? */
+ return match_prefix (ss, default_labels, INT_MAX);
+}
+
+
+static int
+get_precedence (const struct sockaddr_storage *ss)
+{
+ /* XXX What is a good default value? */
+ return match_prefix (ss, default_precedence, 0);
+}
+
+
+static int
+rfc3484_sort (const void *p1, const void *p2)
+{
+ const struct sort_result *a1 = (const struct sort_result *) p1;
+ const struct sort_result *a2 = (const struct sort_result *) p2;
+
+ /* Rule 1: Avoid unusable destinations.
+ We have the got_source_addr flag set if the destination is reachable. */
+ if (a1->got_source_addr && ! a2->got_source_addr)
+ return -1;
+ if (! a1->got_source_addr && a2->got_source_addr)
+ return 1;
+
+
+ /* Rule 2: Prefer matching scope. Only interesting if both
+ destination addresses are IPv6. */
+ int a1_dst_scope
+ = get_scope ((struct sockaddr_storage *) a1->dest_addr->ai_addr);
+
+ int a2_dst_scope
+ = get_scope ((struct sockaddr_storage *) a2->dest_addr->ai_addr);
+
+ if (a1->got_source_addr)
+ {
+ int a1_src_scope = get_scope (&a1->source_addr);
+ int a2_src_scope = get_scope (&a2->source_addr);
+
+ if (a1_dst_scope == a1_src_scope && a2_dst_scope != a2_src_scope)
+ return -1;
+ if (a1_dst_scope != a1_src_scope && a2_dst_scope == a2_src_scope)
+ return 1;
+ }
+
+
+ /* Rule 3: Avoid deprecated addresses.
+ That's something only the kernel could decide. */
+
+ /* Rule 4: Prefer home addresses.
+ Another thing only the kernel can decide. */
+
+ /* Rule 5: Prefer matching label. */
+ if (a1->got_source_addr)
+ {
+ int a1_dst_label
+ = get_label ((struct sockaddr_storage *) a1->dest_addr->ai_addr);
+ int a1_src_label = get_label (&a1->source_addr);
+
+ int a2_dst_label
+ = get_label ((struct sockaddr_storage *) a2->dest_addr->ai_addr);
+ int a2_src_label = get_label (&a2->source_addr);
+
+ if (a1_dst_label == a1_src_label && a2_dst_label != a2_src_label)
+ return -1;
+ if (a1_dst_label != a1_src_label && a2_dst_label == a2_src_label)
+ return 1;
+ }
+
+
+ /* Rule 6: Prefer higher precedence. */
+ int a1_prec
+ = get_precedence ((struct sockaddr_storage *) a1->dest_addr->ai_addr);
+ int a2_prec
+ = get_precedence ((struct sockaddr_storage *) a2->dest_addr->ai_addr);
+
+ if (a1_prec > a2_prec)
+ return -1;
+ if (a1_prec < a2_prec)
+ return 1;
+
+
+ /* Rule 7: Prefer native transport.
+ XXX How to recognize tunnels? */
+
+
+ /* Rule 8: Prefer smaller scope. */
+ if (a1_dst_scope < a2_dst_scope)
+ return -1;
+ if (a1_dst_scope > a2_dst_scope)
+ return 1;
+
+
+ /* Rule 9: Use longest matching prefix. */
+ if (a1->got_source_addr
+ && a1->dest_addr->ai_family == a2->dest_addr->ai_family)
+ {
+ int bit1 = 0;
+ int bit2 = 0;
+
+ if (a1->dest_addr->ai_family == PF_INET)
+ {
+ assert (a1->source_addr.ss_family == PF_INET);
+ assert (a2->source_addr.ss_family == PF_INET);
+
+ struct sockaddr_in *in1_dst;
+ struct sockaddr_in *in1_src;
+ struct sockaddr_in *in2_dst;
+ struct sockaddr_in *in2_src;
+
+ in1_dst = (struct sockaddr_in *) a1->dest_addr->ai_addr;
+ in1_src = (struct sockaddr_in *) &a1->source_addr;
+ in2_dst = (struct sockaddr_in *) a2->dest_addr->ai_addr;
+ in2_src = (struct sockaddr_in *) &a2->source_addr;
+
+ bit1 = ffs (in1_dst->sin_addr.s_addr ^ in1_src->sin_addr.s_addr);
+ bit2 = ffs (in2_dst->sin_addr.s_addr ^ in2_src->sin_addr.s_addr);
+ }
+ else if (a1->dest_addr->ai_family == PF_INET6)
+ {
+ assert (a1->source_addr.ss_family == PF_INET6);
+ assert (a2->source_addr.ss_family == PF_INET6);
+
+ struct sockaddr_in6 *in1_dst;
+ struct sockaddr_in6 *in1_src;
+ struct sockaddr_in6 *in2_dst;
+ struct sockaddr_in6 *in2_src;
+
+ in1_dst = (struct sockaddr_in6 *) a1->dest_addr->ai_addr;
+ in1_src = (struct sockaddr_in6 *) &a1->source_addr;
+ in2_dst = (struct sockaddr_in6 *) a2->dest_addr->ai_addr;
+ in2_src = (struct sockaddr_in6 *) &a2->source_addr;
+
+ int i;
+ for (i = 0; i < 4; ++i)
+ if (in1_dst->sin6_addr.s6_addr32[i]
+ != in1_src->sin6_addr.s6_addr32[i]
+ || (in2_dst->sin6_addr.s6_addr32[i]
+ != in2_src->sin6_addr.s6_addr32[i]))
+ break;
+
+ if (i < 4)
+ {
+ bit1 = ffs (in1_dst->sin6_addr.s6_addr32[i]
+ ^ in1_src->sin6_addr.s6_addr32[i]);
+ bit2 = ffs (in2_dst->sin6_addr.s6_addr32[i]
+ ^ in2_src->sin6_addr.s6_addr32[i]);
+ }
+ }
+
+ if (bit1 > bit2)
+ return -1;
+ if (bit1 < bit2)
+ return 1;
+ }
+
+
+ /* Rule 10: Otherwise, leave the order unchanged. */
+ return 0;
+}
+
+
int
getaddrinfo (const char *name, const char *service,
const struct addrinfo *hints, struct addrinfo **pai)
{
int i = 0, j = 0, last_i = 0;
+ int nresults = 0;
struct addrinfo *p = NULL, **end;
struct gaih *g = gaih, *pg = NULL;
struct gaih_service gaih_service, *pservice;
@@ -1000,7 +1332,11 @@ getaddrinfo (const char *name, const char *service,
return -(i & GAIH_EAI);
}
if (end)
- while(*end) end = &((*end)->ai_next);
+ while (*end)
+ {
+ end = &((*end)->ai_next);
+ ++nresults;
+ }
}
}
++g;
@@ -1009,6 +1345,46 @@ getaddrinfo (const char *name, const char *service,
if (j == 0)
return EAI_FAMILY;
+ if (nresults > 1)
+ {
+ /* Sort results according to RFC 3484. */
+ struct sort_result results[nresults];
+ struct addrinfo *q;
+
+ for (i = 0, q = p; q != NULL; ++i, q = q->ai_next)
+ {
+ results[i].dest_addr = q;
+ results[i].got_source_addr = false;
+
+ /* We overwrite the type with SOCK_DGRAM since we do not
+ want connect() to connect to the other side. If we
+ cannot determine the source address remember this
+ fact. */
+ int fd = __socket (q->ai_family, SOCK_DGRAM, IPPROTO_IP);
+ if (fd != -1)
+ {
+ socklen_t sl = sizeof (results[i].source_addr);
+ if (__connect (fd, q->ai_addr, q->ai_addrlen) == 0
+ && __getsockname (fd,
+ (struct sockaddr *) &results[i].source_addr,
+ &sl) == 0)
+ results[i].got_source_addr = true;
+
+ close_not_cancel_no_status (fd);
+ }
+ }
+
+ /* We got all the source addresses we can get, now sort using
+ the information. */
+ qsort (results, nresults, sizeof (results[0]), rfc3484_sort);
+
+ /* Queue the results up as they come out of sorting. */
+ q = p = results[0].dest_addr;
+ for (i = 1; i < nresults; ++i)
+ q = q->ai_next = results[i].dest_addr;
+ q->ai_next = NULL;
+ }
+
if (p)
{
*pai = p;