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nuttx/libs/libc/netdb/lib_dns.h
zhanghongyu db4840564d dns: Reduce the dns_lock granularity 
When a7 curl calls dns_query via usrsock, it will wait a usrsock
response with the dns lock held. If a7 rptun recv a dns_addnameserver
event from another core at this time, rptun waits the lock held by
curl in callback. Then curl will never get its usrsock response with
rptun blocked, so the deadlock occurs.

This change will break lock when do usrsock request.

Signed-off-by: zhanghongyu <zhanghongyu@xiaomi.com>
2022-11-11 20:07:05 +08:00

291 lines
9.2 KiB
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/****************************************************************************
* libs/libc/netdb/lib_dns.h
* DNS resolver code header file.
*
* Copyright (C) 2007-2009, 2011-2012, 2014 Gregory Nutt.
* All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Inspired by/based on uIP logic by Adam Dunkels:
*
* Copyright (c) 2002-2003, Adam Dunkels. All rights reserved.
* Author Adam Dunkels <adam@dunkels.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE 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 __LIBS_LIBC_NETDB_LIB_DNS_H
#define __LIBS_LIBC_NETDB_LIB_DNS_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdbool.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/dns.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* DNS client configuration *************************************************/
#ifndef CONFIG_NETDB_DNSCLIENT_ENTRIES
# define CONFIG_NETDB_DNSCLIENT_ENTRIES 4
#endif
#ifndef CONFIG_NETDB_DNSCLIENT_MAXRESPONSE
# define CONFIG_NETDB_DNSCLIENT_MAXRESPONSE 96
#endif
#ifndef CONFIG_NETDB_DNSCLIENT_NAMESIZE
# define CONFIG_NETDB_DNSCLIENT_NAMESIZE 32
#endif
#ifndef CONFIG_NETDB_DNSCLIENT_LIFESEC
# define CONFIG_NETDB_DNSCLIENT_LIFESEC 3600
#endif
#ifndef CONFIG_NETDB_RESOLVCONF_PATH
# define CONFIG_NETDB_RESOLVCONF_PATH "/etc/resolv.conf"
#endif
#ifndef CONFIG_NETDB_DNSSERVER_NAMESERVERS
# define CONFIG_NETDB_DNSSERVER_NAMESERVERS 1
#endif
#define DNS_MAX_ADDRSTR 48
#define DNS_MAX_LINE 64
#define NETDB_DNS_KEYWORD "nameserver"
/****************************************************************************
* Public Types
****************************************************************************/
/* This describes either an IPv4 or IPv6 address. It is essentially a named
* alternative to sockaddr_storage.
*/
union dns_addr_u
{
struct sockaddr addr; /* Common address representation */
#ifdef CONFIG_NET_IPv4
struct sockaddr_in ipv4; /* IPv4 address */
#endif
#ifdef CONFIG_NET_IPv6
struct sockaddr_in6 ipv6; /* IPv6 address */
#endif
};
/****************************************************************************
* Public Data
****************************************************************************/
#undef EXTERN
#if defined(__cplusplus)
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
#ifndef CONFIG_NETDB_RESOLVCONF
/* The DNS server addresses */
EXTERN union dns_addr_u g_dns_servers[];
EXTERN uint8_t g_dns_nservers;
#endif
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
/****************************************************************************
* Name: dns_lock
*
* Description:
* Take the DNS mutex, ignoring errors due to the receipt of signals.
*
****************************************************************************/
void dns_lock(void);
/****************************************************************************
* Name: dns_unlock
*
* Description:
* Release the DNS mutex
*
****************************************************************************/
void dns_unlock(void);
/****************************************************************************
* Name: dns_breaklock
*
* Description:
* Break the DNS lock
*
****************************************************************************/
void dns_breaklock(FAR unsigned int *count);
/****************************************************************************
* Name: dns_restorelock
*
* Description:
* Restore the DNS lock
*
****************************************************************************/
void dns_restorelock(unsigned int count);
/****************************************************************************
* Name: dns_bind
*
* Description:
* Initialize the DNS resolver and return a socket bound to the DNS name
* server. The name server was previously selected via dns_server().
*
* Input Parameters:
* None
*
* Returned Value:
* On success, the bound, non-negative socket descriptor is returned. A
* negated errno value is returned on any failure.
*
****************************************************************************/
int dns_bind(sa_family_t family);
/****************************************************************************
* Name: dns_query
*
* Description:
* Using the DNS resolver socket (sd), look up the 'hostname', and
* return its IP address in 'ipaddr'
*
* Input Parameters:
* hostname - The hostname string to be resolved.
* addr - The location to return the IP addresses associated with the
* hostname.
* naddr - On entry, the count of addresses backing up the 'addr'
* pointer. On return, this location will hold the actual count of
* the returned addresses.
*
* Returned Value:
* Returns zero (OK) if the query was successful.
*
****************************************************************************/
int dns_query(FAR const char *hostname, FAR union dns_addr_u *addr,
FAR int *naddr);
/****************************************************************************
* Name: dns_save_answer
*
* Description:
* Save the last resolved hostname in the DNS cache
*
* Input Parameters:
* hostname - The hostname string to be cached.
* addr - The IP addresses associated with the hostname.
* naddr - The count of the IP addresses.
*
* Returned Value:
* None
*
****************************************************************************/
#if CONFIG_NETDB_DNSCLIENT_ENTRIES > 0
void dns_save_answer(FAR const char *hostname,
FAR const union dns_addr_u *addr, int naddr);
#endif
/****************************************************************************
* Name: dns_clear_answer
*
* Description:
* Clear the resolved hostname in the DNS cache
*
* Returned Value:
* None
*
****************************************************************************/
#if CONFIG_NETDB_DNSCLIENT_ENTRIES > 0
void dns_clear_answer(void);
#endif
/****************************************************************************
* Name: dns_find_answer
*
* Description:
* Check if we already have the resolved hostname address in the cache.
*
* Input Parameters:
* hostname - The hostname string to be resolved.
* addr - The location to return the IP addresses associated with the
* hostname.
* naddr - On entry, the count of addresses backing up the 'addr'
* pointer. On return, this location will hold the actual count of
* the returned addresses.
*
* Returned Value:
* If the host name was successfully found in the DNS name resolution
* cache, zero (OK) will be returned. Otherwise, some negated errno
* value will be returned, typically -ENOENT meaning that the hostname
* was not found in the cache.
*
****************************************************************************/
#if CONFIG_NETDB_DNSCLIENT_ENTRIES > 0
int dns_find_answer(FAR const char *hostname, FAR union dns_addr_u *addr,
FAR int *naddr);
#endif
/****************************************************************************
* Name: dns_notify_nameserver
****************************************************************************/
void dns_notify_nameserver(FAR const struct sockaddr *addr,
socklen_t addrlen);
#undef EXTERN
#if defined(__cplusplus)
}
#endif
#endif /* __LIBS_LIBC_NETDB_LIB_DNS_H */
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