mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-27 05:00:15 +00:00
225 lines
8.1 KiB
C++
225 lines
8.1 KiB
C++
/* DNS test framework and libresolv redirection.
|
|
Copyright (C) 2016-2020 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C 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; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C 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 the GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#ifndef SUPPORT_RESOLV_TEST_H
|
|
#define SUPPORT_RESOLV_TEST_H
|
|
|
|
#include <arpa/nameser.h>
|
|
#include <stdbool.h>
|
|
#include <sys/cdefs.h>
|
|
|
|
__BEGIN_DECLS
|
|
|
|
/* Information about EDNS properties of a DNS query. */
|
|
struct resolv_edns_info
|
|
{
|
|
bool active;
|
|
uint8_t extended_rcode;
|
|
uint8_t version;
|
|
uint16_t flags;
|
|
uint16_t payload_size;
|
|
};
|
|
|
|
/* This opaque struct collects information about the resolver testing
|
|
currently in progress. */
|
|
struct resolv_test;
|
|
|
|
/* This struct provides context information when the response callback
|
|
specified in struct resolv_redirect_config is invoked. */
|
|
struct resolv_response_context
|
|
{
|
|
struct resolv_test *test;
|
|
void *client_address;
|
|
size_t client_address_length;
|
|
unsigned char *query_buffer;
|
|
size_t query_length;
|
|
int server_index;
|
|
bool tcp;
|
|
struct resolv_edns_info edns;
|
|
};
|
|
|
|
/* Produces a deep copy of the context. */
|
|
struct resolv_response_context *
|
|
resolv_response_context_duplicate (const struct resolv_response_context *);
|
|
|
|
/* Frees the copy. For the context passed to the response function,
|
|
this happens implicitly. */
|
|
void resolv_response_context_free (struct resolv_response_context *);
|
|
|
|
/* This opaque struct is used to construct responses from within the
|
|
response callback function. */
|
|
struct resolv_response_builder;
|
|
|
|
enum
|
|
{
|
|
/* Maximum number of test servers supported by the framework. */
|
|
resolv_max_test_servers = 3,
|
|
};
|
|
|
|
/* Configuration settings specific to individual test servers. */
|
|
struct resolv_redirect_server_config
|
|
{
|
|
bool disable_tcp; /* If true, no TCP server is listening. */
|
|
bool disable_udp; /* If true, no UDP server is listening. */
|
|
};
|
|
|
|
/* Instructions for setting up the libresolv redirection. */
|
|
struct resolv_redirect_config
|
|
{
|
|
/* The response_callback function is called for every incoming DNS
|
|
packet, over UDP or TCP. It must be specified, the other
|
|
configuration settings are optional. */
|
|
void (*response_callback) (const struct resolv_response_context *,
|
|
struct resolv_response_builder *,
|
|
const char *qname,
|
|
uint16_t qclass, uint16_t qtype);
|
|
|
|
/* Per-server configuration. */
|
|
struct resolv_redirect_server_config servers[resolv_max_test_servers];
|
|
|
|
/* Search path entries. The first entry serves as the default
|
|
domain name as well. */
|
|
const char *search[7];
|
|
|
|
/* Number of servers to activate in resolv. 0 means the default,
|
|
resolv_max_test_servers. */
|
|
int nscount;
|
|
|
|
/* If true, use a single thread to process all UDP queries. This
|
|
may results in more predictable ordering of queries and
|
|
responses. */
|
|
bool single_thread_udp;
|
|
|
|
/* Do not rewrite the _res variable or change NSS defaults. Use
|
|
server_address_overrides below to tell the testing framework on
|
|
which addresses to create the servers. */
|
|
bool disable_redirect;
|
|
|
|
/* Use these addresses for creating the DNS servers. The array must
|
|
have ns_count (or resolv_max_test_servers) sockaddr * elements if
|
|
not NULL. */
|
|
const struct sockaddr *const *server_address_overrides;
|
|
};
|
|
|
|
/* Configure NSS to use, nss_dns only for aplicable databases, and try
|
|
to put the process into a network namespace for better isolation.
|
|
This may have to be called before resolv_test_start, before the
|
|
process creates any threads. Otherwise, initialization is
|
|
performed by resolv_test_start implicitly. */
|
|
void resolv_test_init (void);
|
|
|
|
/* Initiate resolver testing. This updates the _res variable as
|
|
needed. As a side effect, NSS is reconfigured to use nss_dns only
|
|
for aplicable databases, and the process may enter a network
|
|
namespace for better isolation. */
|
|
struct resolv_test *resolv_test_start (struct resolv_redirect_config);
|
|
|
|
/* Call this function at the end of resolver testing, to free
|
|
resources and report pending errors (if any). */
|
|
void resolv_test_end (struct resolv_test *);
|
|
|
|
/* The remaining facilities in this file are used for constructing
|
|
response packets from the response_callback function. */
|
|
|
|
/* Special settings for constructing responses from the callback. */
|
|
struct resolv_response_flags
|
|
{
|
|
/* 4-bit response code to incorporate into the response. */
|
|
unsigned char rcode;
|
|
|
|
/* If true, the TC (truncation) flag will be set. */
|
|
bool tc;
|
|
|
|
/* If true, the AD (authenticated data) flag will be set. */
|
|
bool ad;
|
|
|
|
/* If true, do not set the RA (recursion available) flag in the
|
|
response. */
|
|
bool clear_ra;
|
|
|
|
/* Initial section count values. Can be used to artificially
|
|
increase the counts, for malformed packet testing.*/
|
|
unsigned short qdcount;
|
|
unsigned short ancount;
|
|
unsigned short nscount;
|
|
unsigned short adcount;
|
|
};
|
|
|
|
/* Begin a new response with the requested flags. Must be called
|
|
first. */
|
|
void resolv_response_init (struct resolv_response_builder *,
|
|
struct resolv_response_flags);
|
|
|
|
/* Switches to the section in the response packet. Only forward
|
|
movement is supported. */
|
|
void resolv_response_section (struct resolv_response_builder *, ns_sect);
|
|
|
|
/* Add a question record to the question section. */
|
|
void resolv_response_add_question (struct resolv_response_builder *,
|
|
const char *name, uint16_t class,
|
|
uint16_t type);
|
|
/* Starts a new resource record with the specified owner name, class,
|
|
type, and TTL. Data is supplied with resolv_response_add_data or
|
|
resolv_response_add_name. */
|
|
void resolv_response_open_record (struct resolv_response_builder *,
|
|
const char *name, uint16_t class,
|
|
uint16_t type, uint32_t ttl);
|
|
|
|
/* Add unstructed bytes to the RDATA part of a resource record. */
|
|
void resolv_response_add_data (struct resolv_response_builder *,
|
|
const void *, size_t);
|
|
|
|
/* Add a compressed domain name to the RDATA part of a resource
|
|
record. */
|
|
void resolv_response_add_name (struct resolv_response_builder *,
|
|
const char *name);
|
|
|
|
/* Mark the end of the constructed record. Must be called last. */
|
|
void resolv_response_close_record (struct resolv_response_builder *);
|
|
|
|
/* Drop this query packet (that is, do not send a response, not even
|
|
an empty packet). */
|
|
void resolv_response_drop (struct resolv_response_builder *);
|
|
|
|
/* In TCP mode, close the connection after this packet (if a response
|
|
is sent). */
|
|
void resolv_response_close (struct resolv_response_builder *);
|
|
|
|
/* The size of the response packet built so far. */
|
|
size_t resolv_response_length (const struct resolv_response_builder *);
|
|
|
|
/* Allocates a response builder tied to a specific query packet,
|
|
starting at QUERY_BUFFER, containing QUERY_LENGTH bytes. */
|
|
struct resolv_response_builder *
|
|
resolv_response_builder_allocate (const unsigned char *query_buffer,
|
|
size_t query_length);
|
|
|
|
/* Deallocates a response buffer. */
|
|
void resolv_response_builder_free (struct resolv_response_builder *);
|
|
|
|
/* Sends a UDP response using a specific context. This can be used to
|
|
reorder or duplicate responses, along with
|
|
resolv_response_context_duplicate and
|
|
response_builder_allocate. */
|
|
void resolv_response_send_udp (const struct resolv_response_context *,
|
|
struct resolv_response_builder *);
|
|
|
|
__END_DECLS
|
|
|
|
#endif /* SUPPORT_RESOLV_TEST_H */
|