Merge "Misc cleanups for getaddrinfo.cpp"

 * SUCH DAMAGE.

 */

/*

 * Issues to be discussed:

 * - Thread safe-ness must be checked.

 * - Return values.  There are nonstandard return values defined and used

 *   in the source code.  This is because RFC2553 is silent about which error

 *   code must be returned for which situation.

 * - IPv4 classful (shortened) form.  RFC2553 is silent about it.  XNET 5.2

 *   says to use inet_aton() to convert IPv4 numeric to binary (alows

 *   classful form as a result).

 *   current code - disallow classful form for IPv4 (due to use of inet_pton).

 * Note:

 * - We use getipnodebyname() just for thread-safeness.  There's no intent

 *   to let it do PF_UNSPEC (actually we never pass PF_UNSPEC to

 *   getipnodebyname().

 * - The code filters out AFs that are not supported by the kernel,

 *   when globbing NULL hostname (to loopback, or wildcard).  Is it the right

 *   thing to do?  What is the relationship with post-RFC2553 AI_ADDRCONFIG

 *   in ai_flags?

 * - (post-2553) semantics of AI_ADDRCONFIG itself is too vague.

 *   (1) what should we do against numeric hostname (2) what should we do

 *   against NULL hostname (3) what is AI_ADDRCONFIG itself.  AF not ready?

 *   non-loopback address configured?  global address configured?

 * - To avoid search order issue, we have a big amount of code duplicate

 *   from gethnamaddr.c and some other places.  The issues that there's no

 *   lower layer function to lookup "IPv4 or IPv6" record.  Calling

 *   gethostbyname2 from getaddrinfo will end up in wrong search order, as

 *   follows:

 *	- The code makes use of following calls when asked to resolver with

 *	  ai_family  = PF_UNSPEC:

 *		getipnodebyname(host, AF_INET6);

 *		getipnodebyname(host, AF_INET);

 *	  This will result in the following queries if the node is configure to

 *	  prefer /etc/hosts than DNS:

 *		lookup /etc/hosts for IPv6 address

 *		lookup DNS for IPv6 address

 *		lookup /etc/hosts for IPv4 address

 *		lookup DNS for IPv4 address

 *	  which may not meet people's requirement.

 *	  The right thing to happen is to have underlying layer which does

 *	  PF_UNSPEC lookup (lookup both) and return chain of addrinfos.

 *	  This would result in a bit of code duplicate with _dns_ghbyname() and

 *	  friends.

 */

#include <arpa/inet.h>

#include <arpa/nameser.h>

#include <assert.h>

#define ANY 0

static const char in_addrany[] = {0, 0, 0, 0};

static const char in_loopback[] = {127, 0, 0, 1};

static const char in6_addrany[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

static const char in6_loopback[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};

const char in_addrany[] = {0, 0, 0, 0};

const char in_loopback[] = {127, 0, 0, 1};

const char in6_addrany[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

const char in6_loopback[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};

static const struct afd {

const struct afd {

    int a_af;

    int a_addrlen;

    int a_socklen;

#define WILD_PROTOCOL(ex) ((ex)->e_wild & 0x04)

};

static const struct explore explore_options[] = {

const struct explore explore_options[] = {

        {PF_INET6, SOCK_DGRAM, IPPROTO_UDP, 0x07},

        {PF_INET6, SOCK_STREAM, IPPROTO_TCP, 0x07},

        {PF_INET6, SOCK_RAW, ANY, 0x05},

static int res_querydomainN(const char* name, const char* domain, res_target* target, res_state res,

                            int* ai_error);

static const char* const ai_errlist[] = {

const char* const ai_errlist[] = {

        "Success",

        "Address family for hostname not supported",    /* EAI_ADDRFAMILY */

        "Temporary failure in name resolution",         /* EAI_AGAIN      */

    return _find_src_addr(&addr.sa, NULL, mark, uid) == 1;

}

bool readBE32(FILE* fp, int32_t* result) {

    int32_t tmp;

    if (fread(&tmp, sizeof(tmp), 1, fp) != 1) {

        return false;

    }

    *result = ntohl(tmp);

    return true;

}

// Internal version of getaddrinfo(), but limited to AI_NUMERICHOST.

// NOTE: also called by resolv_set_nameservers_for_net().

int getaddrinfo_numeric(const char* hostname, const char* servname, addrinfo hints,