MEDIUM: dns: implement a DNS resolver
Implementation of a DNS client in HAProxy to perform name resolution to
IP addresses.
It relies on the freshly created UDP client to perform the DNS
resolution. For now, all UDP socket calls are performed in the
DNS layer, but this might change later when the protocols are
extended to be more suited to datagram mode.
A new section called 'resolvers' is introduced thanks to this patch. It
is used to describe DNS servers IP address and also many parameters.
diff --git a/include/proto/dns.h b/include/proto/dns.h
new file mode 100644
index 0000000..328298e
--- /dev/null
+++ b/include/proto/dns.h
@@ -0,0 +1,49 @@
+/*
+ * include/proto/dns.h
+ * This file provides functions related to DNS protocol
+ *
+ * Copyright (C) 2014 Baptiste Assmann <bedis9@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, version 2.1
+ * exclusively.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef _PROTO_DNS_H
+#define _PROTO_DNS_H
+
+#include <types/dns.h>
+#include <types/proto_udp.h>
+
+char *dns_str_to_dn_label(char *string, char *dn, int dn_len);
+int dns_str_to_dn_label_len(const char *string);
+int dns_hostname_validation(const char *string, char **err);
+int dns_build_query(int query_id, int query_type, char *hostname_dn, int hostname_dn_len, char *buf, int bufsize);
+struct task *dns_process_resolve(struct task *t);
+int dns_init_resolvers(void);
+uint16_t dns_rnd16(void);
+int dns_validate_dns_response(unsigned char *resp, unsigned char *bufend, char *dn_name, int dn_name_len);
+int dns_get_ip_from_response(unsigned char *resp, unsigned char *resp_end,
+ char *dn_name, int dn_name_len, void *currentip,
+ short currentip_sin_family, int family_priority,
+ void **newip, short *newip_sin_family);
+void dns_resolve_send(struct dgram_conn *dgram);
+void dns_resolve_recv(struct dgram_conn *dgram);
+int dns_send_query(struct dns_resolution *resolution);
+void dns_print_current_resolutions(struct dns_resolvers *resolvers);
+void dns_update_resolvers_timeout(struct dns_resolvers *resolvers);
+void dns_reset_resolution(struct dns_resolution *resolution);
+int dns_check_resolution_queue(struct dns_resolvers *resolvers);
+int dns_response_get_query_id(unsigned char *resp);
+
+#endif // _PROTO_DNS_H