1 files changed, 61 insertions, 0 deletions
diff --git a/src/get_ipv6_addr.c b/src/get_ipv6_addr.c
new file mode 100644
index 0000000..44edc7a
--- /dev/null
+++ b/src/get_ipv6_addr.c
@@ -0,0 +1,61 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <string.h>
+#include <arpa/inet.h>
+
+/*
+ * Returns the IPv6 address with which you have connectivity at the moment.
+ *
+ */
+const char *get_ipv6_addr() {
+	static char buf[INET6_ADDRSTRLEN+1];
+	struct addrinfo hints;
+	struct addrinfo *result, *resp;
+	int fd;
+
+	memset(&hints, 0, sizeof(struct addrinfo));
+	hints.ai_family = AF_INET6;
+
+	if (getaddrinfo("k.root-servers.net", "domain", &hints, &result) != 0) {
+		perror("getaddrinfo()");
+		return "no IP";
+	}
+
+	for (resp = result; resp != NULL; resp = resp->ai_next) {
+		if ((fd = socket(resp->ai_family, SOCK_STREAM, 0)) == -1) {
+			perror("socket()");
+			continue;
+		}
+
+		if (connect(fd, resp->ai_addr, resp->ai_addrlen) == -1) {
+			perror("connect()");
+			continue;
+		}
+
+		struct sockaddr_storage local;
+		socklen_t local_len = sizeof(struct sockaddr_storage);
+		if (getsockname(fd, (struct sockaddr*)&local, &local_len) == -1) {
+			perror("getsockname()");
+			return "no IP";
+		}
+
+		memset(buf, 0, INET6_ADDRSTRLEN + 1);
+		int ret;
+		if ((ret = getnameinfo((struct sockaddr*)&local, local_len, buf, sizeof(buf), NULL, 0, NI_NUMERICHOST)) != 0) {
+			fprintf(stderr, "getnameinfo(): %s\n", gai_strerror(ret));
+			return "no IP";
+		}
+
+		(void)close(fd);
+
+		free(result);
+		return buf;
+	}
+
+	free(result);
+	return "no IP";
+}