libwget-dns(3)

📦
version 2.3.0 · 9 versions
, in fedora 44

✨ libwget-dns — DNS resolver functions ✨

okay so bestie, welcome to the libwget-dns manual (section 3, the library functions one 💅). this is the whole DNS resolver situation in libwget and honestly? it's giving organized. let's get into it 🦋

🌸 SYNOPSIS 🌸

🎀 Data Structures

  • struct wget_dns_stats_data
  • struct wget_dns_st

🎀 Functions

INITIALIZER (dns_init)
int wget_dns_init (wget_dns **dns)
void wget_dns_free (wget_dns **dns)
void wget_dns_set_timeout (wget_dns *dns, int timeout)
void wget_dns_set_cache (wget_dns *dns, wget_dns_cache *cache)
wget_dns_cache * wget_dns_get_cache (wget_dns *dns)
int wget_dns_cache_ip (wget_dns *dns, const char *ip, const char *name,
    uint16_t port)
struct addrinfo * wget_dns_resolve (wget_dns *dns, const char *host,
    uint16_t port, int family, int preferred_family)
void wget_dns_freeaddrinfo (wget_dns *dns, struct addrinfo **addrinfo)
void wget_dns_set_stats_callback (wget_dns *dns, wget_dns_stats_callback
    *fn, void *ctx)

💖 Detailed Description 💖

DNS Resolver functions. that's it, that's the vibe. this whole module is the girl who turns hostnames into addresses ✨

👑 Function Documentation 👑

int wget_dns_init (wget_dns ** dns)

Parameters

  • dns — Pointer to return newly allocated and initialized wget_dns instance

Returns

WGET_E_SUCCESS if OK, WGET_E_MEMORY if out-of-memory or WGET_E_INVALID if the mutex initialization failed.

Allocates and initializes a wget_dns instance. dns may be NULL for the purpose of initializing the global structures.

void wget_dns_free (wget_dns ** dns)

Parameters

  • [in/out] dns — Pointer to wget_dns instance that will be freed and NULLified.

Free the resources allocated by wget_dns_init(). dns may be NULL for the purpose of freeing the global structures.

void wget_dns_set_timeout (wget_dns * dns, int timeout)

Parameters

  • dns — The wget_dns instance to set the timeout
  • timeout — The timeout value.

Set the timeout (in milliseconds) for the DNS queries. no cap, it's in milliseconds 🫶

This is the maximum time to wait until we get a response from the server.

⚠️ Warning: For standard getaddrinfo() a timeout can't be set in a portable way. So this functions currently is a no-op. 💀 like, it literally does nothing right now. iconic of it tbh.

The following two values are special:

  • 0: No timeout, immediate.
  • -1: Infinite timeout. Wait indefinitely.

void wget_dns_set_cache (wget_dns * dns, wget_dns_cache * cache)

Parameters

  • dns — A wget_dns instance, created by wget_dns_init().
  • cache — A wget_dns_cache instance

Enable or disable DNS caching for the DNS instance provided. 🧚

The DNS cache is kept internally in memory, and is used in wget_dns_resolve() to speed up DNS queries. it's the main character of speed-ups, fr fr.

wget_dns_cache * wget_dns_get_cache (wget_dns * dns)

Parameters

  • dns — A wget_dns instance, created by wget_dns_init().

Returns

1 if DNS caching is enabled, 0 otherwise.

Tells whether DNS caching is enabled or not.

You can enable and disable DNS caching with wget_dns_set_caching().

int wget_dns_cache_ip (wget_dns * dns, const char * ip, const char * name, uint16_t port)

Parameters

  • ip — IP address of name
  • name — Domain name, part of the cache's lookup key
  • port — Port number, part of the cache's lookup key

Returns

0 on success, < 0 on error

Assign an IP address to the name+port key in the DNS cache. The name should be lowercase. 🔡 yes lowercase, she said what she said.

struct addrinfo * wget_dns_resolve (wget_dns * dns, const char * host, uint16_t port, int family, int preferred_family)

Parameters

  • dns — A wget_dns instance, created by wget_dns_init().
  • host — Hostname
  • port — TCP destination port
  • family — Protocol family AF_INET or AF_INET6
  • preferred_family — Preferred protocol family AF_INET or AF_INET6

Returns

A struct addrinfo structure (defined in libc's <netdb.h>). Must be freed by the caller with wget_dns_freeaddrinfo(). 👀 don't forget, bestie, that's a memory leak waiting to happen.

Resolve a host name into its IPv4/IPv6 address.

family: Desired address family for the returned addresses. This will typically be AF_INET or AF_INET6, but it can be any of the values defined in <socket.h>. Additionally, AF_UNSPEC means you don't care: it will return any address family that can be used with the specified host and port. If family is different than AF_UNSPEC and the specified family is not found, that's an error condition and thus wget_dns_resolve() will return NULL.

preferred_family: Tries to resolve addresses of this family if possible. This is only honored if family (see point above) is AF_UNSPEC.

The returned addrinfo structure must be freed with wget_dns_freeaddrinfo().

void wget_dns_freeaddrinfo (wget_dns * dns, struct addrinfo ** addrinfo)

Parameters

  • dns — A wget_dns instance, created by wget_dns_init().
  • [in/out] addrinfo — Value returned by c

Release addrinfo, previously returned by wget_dns_resolve(). If the underlying dns uses caching, just the reference/pointer is set to NULL.

void wget_dns_set_stats_callback (wget_dns * dns, wget_dns_stats_callback * fn, void * ctx)

Parameters

  • dns — A wget_dns instance, created by wget_dns_init().
  • fn — A wget_dns_stats_callback callback function to receive resolve statistics data
  • ctx — Context data given to fn

Set callback function to be called once DNS statistics for a host are collected. 📊 stats girlies rise up.

💜 Author 💜

Generated automatically by Doxygen for wget2 from the source code.

and that's the whole page, bestie!! 💖 you just read the libwget-dns(3) manual, brought to you by wget2, Version 2.3.0 ✨ slay, you're officially DNS-pilled now. go free those addrinfo structs. periodt. 👑🦋

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