dns Namespace Reference

Namespaces
	anonymous_namespace{dns.cc}

Classes
class	Host
class	Resolver
class	CaresResolver
class	HostfileResolver
class	NormalResolver

Enumerations
enum	Failures {   kFailOk = 0, kFailInvalidResolvers, kFailTimeout, kFailInvalidHost,   kFailUnknownHost, kFailMalformed, kFailNoAddress, kFailNotYetResolved,   kFailOther, kFailNumEntries }
enum	IpPreference { kIpPreferSystem = 0, kIpPreferV4, kIpPreferV6 }

Functions
static void	PinpointHostSubstr (const std::string &url, unsigned *pos_begin, unsigned *pos_end)
std::string	ExtractHost (const std::string &url)
std::string	ExtractPort (const std::string &url)
string	RewriteUrl (const string &url, const string &ip)
string	StripIp (const string &decorated_ip)
std::string	AddDefaultScheme (const std::string &proxy)
static Failures	CaresExtractIpv4 (const unsigned char *abuf, int alen, vector< string > *addresses, unsigned *ttl, string *fqdn)
static Failures	CaresExtractIpv6 (const unsigned char *abuf, int alen, vector< string > *addresses, unsigned *ttl, string *fqdn)
static void	CallbackCares (void *arg, int status, int timeouts_ms, unsigned char *abuf, int alen)
static bool	SortNameLength (const string &a, const string &b)
const char *	Code2Ascii (const Failures error)
std::string	RewriteUrl (const std::string &url, const std::string &ip)
std::string	StripIp (const std::string &decorated_ip)

Detailed Description

This file is part of the CernVM File System.

Enumeration Type Documentation

enum dns::Failures

Possible errors when trying to resolve a host name.

Enumerator
kFailOk
kFailInvalidResolvers
kFailTimeout
kFailInvalidHost
kFailUnknownHost	Resolver returned a negative reply.
kFailMalformed
kFailNoAddress	Resolver returned a positive reply but without IPs.
kFailNotYetResolved
kFailOther
kFailNumEntries

Definition at line 28 of file dns.h.

enum dns::IpPreference

Steers IP protocol selection.

Enumerator
kIpPreferSystem
kIpPreferV4
kIpPreferV6

Definition at line 46 of file dns.h.

Function Documentation

std::string dns::AddDefaultScheme

(

const std::string &

proxy

)

Adds http:// if it is missing from proxy

Definition at line 187 of file dns.cc.

Referenced by download::DownloadManager::SetProxyChain().

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static void dns::CallbackCares ( void *  arg, int  status, int  timeouts_ms, unsigned char *  abuf, int  alen  )

static

Called when a DNS query returns or times out. Sets the return status and the IP addresses (if successful) in the QueryInfo object.

Definition at line 564 of file dns.cc.

Referenced by dns::CaresResolver::DoResolve().

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static Failures dns::CaresExtractIpv4 ( const unsigned char *  abuf, int  alen, vector< string > *  addresses, unsigned *  ttl, string *  fqdn  )

static

Extracts IPv4 addresses from an A record return in c-ares. TTLs are merged to a single one, representing the minimum.

Definition at line 617 of file dns.cc.

Referenced by CallbackCares().

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static Failures dns::CaresExtractIpv6 ( const unsigned char *  abuf, int  alen, vector< string > *  addresses, unsigned *  ttl, string *  fqdn  )

static

Definition at line 668 of file dns.cc.

Referenced by CallbackCares().

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const char* dns::Code2Ascii ( const Failures  error )

inline

Definition at line 53 of file dns.h.

Referenced by dns::Resolver::ResolveMany(), download::DownloadManager::SetProxyChain(), and download::DownloadManager::ValidateProxyIpsUnlocked().

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std::string dns::ExtractHost

(

const std::string &

url

)

Returns the host name from a string in the format http://<hostname>:<port>[/path] or an empty string if url doesn't match the format.

Definition at line 110 of file dns.cc.

Referenced by download::DownloadManager::GeoSortServers(), s3fanout::S3FanoutManager::InitializeDnsSettings(), download::DownloadManager::ProbeGeo(), and download::DownloadManager::SetProxyChain().

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std::string dns::ExtractPort

(

const std::string &

url

)

Returns the port from a string in the format http://<hostname>:<port>/path or an empty string if url doesn't match the format.

Definition at line 125 of file dns.cc.

Referenced by s3fanout::S3FanoutManager::InitializeDnsSettings().

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static void dns::PinpointHostSubstr ( const std::string &  url, unsigned *  pos_begin, unsigned *  pos_end  )

static

Sets pos_begin and pos_end to the first/last character of the host name in a string like http://<hostname>:<port>. Works also if the host name is an IPv4/6 address. Sets pos_begin and pos_end to 0 if url doesn't match the format.

Definition at line 53 of file dns.cc.

Referenced by ExtractHost(), ExtractPort(), and RewriteUrl().

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std::string dns::RewriteUrl	(	const std::string &	url,
		const std::string &	ip
	)

string dns::RewriteUrl	(	const string &	url,
		const string &	ip
	)

Replaces the host name in the url with the given IP address. If it is an IPv6 address, it has to be in brackets. If the input is not a valid URL, it is returned unmodified.

Definition at line 156 of file dns.cc.

Referenced by download::DownloadManager::SetProxyChain(), and download::DownloadManager::ValidateProxyIpsUnlocked().

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static bool dns::SortNameLength ( const string &  a, const string &  b  )

static

Used to process longer domain names before shorter ones, in order to get the correct fully qualified domain name. Reversed return value in order to sort in descending order.

Definition at line 1082 of file dns.cc.

Referenced by dns::HostfileResolver::DoResolve().

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std::string dns::StripIp

(

const std::string &

decorated_ip

)

string dns::StripIp

(

const string &

decorated_ip

)

Removes the brackets from IPv6 addresses. Leaves IPv4 addresses unchanged.

Definition at line 172 of file dns.cc.