Rework resolver library.

1 files changed, 222 insertions, 0 deletions

diff --git a/src/dns_private.h b/src/dns_private.h
new file mode 100644
index 000000000..46483918e
--- /dev/null
+++ b/src/dns_private.h
@@ -0,0 +1,222 @@
+/* Copyright (c) 2014, Vsevolod Stakhov
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *       * Redistributions of source code must retain the above copyright
+ *         notice, this list of conditions and the following disclaimer.
+ *       * Redistributions in binary form must reproduce the above copyright
+ *         notice, this list of conditions and the following disclaimer in the
+ *         documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED ''AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef DNS_PRIVATE_H_
+#define DNS_PRIVATE_H_
+
+#include "config.h"
+#include "chacha_private.h"
+
+#define MAX_SERVERS 16
+/* Upstream timeouts */
+#define DEFAULT_UPSTREAM_ERROR_TIME 10
+#define DEFAULT_UPSTREAM_DEAD_TIME 300
+#define DEFAULT_UPSTREAM_MAXERRORS 10
+
+static const unsigned base = 36;
+static const unsigned t_min = 1;
+static const unsigned t_max = 26;
+static const unsigned skew = 38;
+static const unsigned damp = 700;
+static const unsigned initial_n = 128;
+static const unsigned initial_bias = 72;
+
+static const gint dns_port = 53;
+
+#define UDP_PACKET_SIZE 4096
+
+#define DNS_COMPRESSION_BITS 0xC0
+
+#define DNS_D_MAXLABEL  63      /* + 1 '\0' */
+#define DNS_D_MAXNAME   255     /* + 1 '\0' */
+
+#define PERMUTOR_BUF_SIZE 32768
+#define PERMUTOR_KSIZE 32
+#define PERMUTOR_IVSIZE 8
+
+#define RESOLV_CONF "/etc/resolv.conf"
+
+/**
+ * Represents DNS server
+ */
+struct rspamd_dns_server {
+	struct upstream up; /**< upstream structure                                         */
+	gchar *name; /**< name of DNS server                                         */
+	struct rspamd_dns_io_channel *io_channels;
+	struct rspamd_dns_io_channel *cur_io_channel;
+};
+
+/**
+ * IO channel for a specific DNS server
+ */
+struct rspamd_dns_io_channel {
+	struct rspamd_dns_server *srv;
+	struct rspamd_dns_resolver *resolver;
+	gint sock; /**< persistent socket                                          */
+	struct event ev;
+	GHashTable *requests; /**< requests in flight                                         */
+	struct rspamd_dns_io_channel *prev, *next;
+};
+
+struct dns_permutor;
+
+struct rspamd_dns_resolver {
+	struct rspamd_dns_server servers[MAX_SERVERS];
+	gint servers_num; /**< number of DNS servers registered           */
+	struct dns_permutor *permutor; /**< permutor for randomizing request id        */
+	guint request_timeout;
+	guint max_retransmits;
+	guint max_errors;
+	GHashTable *io_channels; /**< hash of io chains indexed by socket        */
+	gboolean throttling; /**< dns servers are busy                                       */
+	gboolean is_master_slave; /**< if this is true, then select upstreams as master/slave */
+	guint errors; /**< resolver errors                                            */
+	struct timeval throttling_time; /**< throttling time                                            */
+	struct event throttling_event; /**< throttling event                                           */
+	struct event_base *ev_base; /**< base for event ops                                         */
+};
+
+struct dns_header;
+struct dns_query;
+
+/* Internal DNS structs */
+
+struct dns_header {
+	guint qid :16;
+
+#if BYTE_ORDER == BIG_ENDIAN
+	guint qr:1;
+	guint opcode:4;
+	guint aa:1;
+	guint tc:1;
+	guint rd:1;
+
+	guint ra:1;
+	guint unused:3;
+	guint rcode:4;
+#else
+	guint rd :1;
+	guint tc :1;
+	guint aa :1;
+	guint opcode :4;
+	guint qr :1;
+
+	guint rcode :4;
+	guint unused :3;
+	guint ra :1;
+#endif
+
+	guint qdcount :16;
+	guint ancount :16;
+	guint nscount :16;
+	guint arcount :16;
+};
+
+enum dns_section {
+	DNS_S_QD = 0x01,
+#define DNS_S_QUESTION          DNS_S_QD
+
+	DNS_S_AN = 0x02,
+#define DNS_S_ANSWER            DNS_S_AN
+
+	DNS_S_NS = 0x04,
+#define DNS_S_AUTHORITY         DNS_S_NS
+
+	DNS_S_AR = 0x08,
+#define DNS_S_ADDITIONAL        DNS_S_AR
+
+	DNS_S_ALL = 0x0f
+};
+/* enum dns_section */
+
+enum dns_opcode {
+	DNS_OP_QUERY = 0,
+	DNS_OP_IQUERY = 1,
+	DNS_OP_STATUS = 2,
+	DNS_OP_NOTIFY = 4,
+	DNS_OP_UPDATE = 5,
+};
+/* dns_opcode */
+
+enum dns_class {
+	DNS_C_IN = 1,
+
+	DNS_C_ANY = 255
+};
+/* enum dns_class */
+
+struct dns_query {
+	gchar *qname;
+	guint qtype :16;
+	guint qclass :16;
+};
+
+enum dns_type {
+	DNS_T_A = 1,
+	DNS_T_NS = 2,
+	DNS_T_CNAME = 5,
+	DNS_T_SOA = 6,
+	DNS_T_PTR = 12,
+	DNS_T_MX = 15,
+	DNS_T_TXT = 16,
+	DNS_T_AAAA = 28,
+	DNS_T_SRV = 33,
+	DNS_T_OPT = 41,
+	DNS_T_SSHFP = 44,
+	DNS_T_SPF = 99,
+
+	DNS_T_ALL = 255
+};
+/* enum dns_type */
+
+struct dns_permutor {
+	chacha_ctx ctx;
+	guchar perm_buf[PERMUTOR_BUF_SIZE];
+	guint pos;
+};
+
+static const gchar dns_rcodes[16][16] = {
+	[DNS_RC_NOERROR]  = "NOERROR",
+	[DNS_RC_FORMERR]  = "FORMERR",
+	[DNS_RC_SERVFAIL] = "SERVFAIL",
+	[DNS_RC_NXDOMAIN] = "NXDOMAIN",
+	[DNS_RC_NOTIMP]   = "NOTIMP",
+	[DNS_RC_REFUSED]  = "REFUSED",
+	[DNS_RC_YXDOMAIN] = "YXDOMAIN",
+	[DNS_RC_YXRRSET]  = "YXRRSET",
+	[DNS_RC_NXRRSET]  = "NXRRSET",
+	[DNS_RC_NOTAUTH]  = "NOTAUTH",
+	[DNS_RC_NOTZONE]  = "NOTZONE",
+};
+
+static const gchar dns_types[7][16] = {
+		[DNS_REQUEST_A] = "A request",
+		[DNS_REQUEST_PTR] = "PTR request",
+		[DNS_REQUEST_MX] = "MX request",
+		[DNS_REQUEST_TXT] = "TXT request",
+		[DNS_REQUEST_SRV] = "SRV request",
+		[DNS_REQUEST_SPF] = "SPF request",
+		[DNS_REQUEST_AAA] = "AAA request"
+};
+
+#endif /* DNS_PRIVATE_H_ */