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path: root/src/network/__dns.c
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Diffstat (limited to 'src/network/__dns.c')
-rw-r--r--src/network/__dns.c36
1 files changed, 31 insertions, 5 deletions
diff --git a/src/network/__dns.c b/src/network/__dns.c
index 8f3c6370..97d8031c 100644
--- a/src/network/__dns.c
+++ b/src/network/__dns.c
@@ -11,6 +11,7 @@
#include <ctype.h>
#include <unistd.h>
#include <pthread.h>
+#include <errno.h>
#include "__dns.h"
#include "stdio_impl.h"
@@ -35,9 +36,9 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
} sa = {0}, ns[3] = {{0}};
- socklen_t sl;
+ socklen_t sl = sizeof sa.sin;
int nns = 0;
- int family = AF_UNSPEC;
+ int family = AF_INET;
unsigned char q[280] = "", *r = dest;
int ql;
int rlen;
@@ -75,10 +76,12 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
for (s=line+11; isspace(*s); s++);
for (z=s; *z && !isspace(*z); z++);
*z=0;
- if (__ipparse(ns+nns, family, s) < 0) continue;
+ if (__ipparse(ns+nns, AF_UNSPEC, s) < 0) continue;
ns[nns].sin.sin_port = htons(53);
- family = ns[nns++].sin.sin_family;
- sl = family==AF_INET6 ? sizeof sa.sin6 : sizeof sa.sin;
+ if (ns[nns++].sin.sin_family == AF_INET6) {
+ family = AF_INET6;
+ sl = sizeof sa.sin6;
+ }
}
if (f) __fclose_ca(f);
if (!nns) {
@@ -93,6 +96,29 @@ int __dns_doqueries(unsigned char *dest, const char *name, int *rr, int rrcnt)
sa.sin.sin_family = family;
fd = socket(family, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ /* Handle case where system lacks IPv6 support */
+ if (fd < 0 && errno == EAFNOSUPPORT) {
+ if (family != AF_INET6) return EAI_SYSTEM;
+ fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ family = AF_INET;
+ }
+ if (fd < 0) return EAI_SYSTEM;
+
+ /* Convert any IPv4 addresses in a mixed environment to v4-mapped */
+ if (family == AF_INET6) {
+ setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &(int){0}, sizeof 0);
+ for (i=0; i<nns; i++) {
+ if (ns[i].sin.sin_family != AF_INET) continue;
+ memcpy(ns[i].sin6.sin6_addr.s6_addr+12,
+ &ns[i].sin.sin_addr, 4);
+ memcpy(ns[i].sin6.sin6_addr.s6_addr,
+ "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
+ ns[i].sin6.sin6_family = AF_INET6;
+ ns[i].sin6.sin6_flowinfo = 0;
+ ns[i].sin6.sin6_scope_id = 0;
+ }
+ }
+
pthread_cleanup_push(cleanup, (void *)(intptr_t)fd);
pthread_setcancelstate(cs, 0);