ares__readaddrinfo.c
6.49 KB
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/* Copyright (C) 2019 by Andrew Selivanov
*
* Permission to use, copy, modify, and distribute this
* software and its documentation for any purpose and without
* fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting
* documentation, and that the name of M.I.T. not be used in
* advertising or publicity pertaining to distribution of the
* software without specific, written prior permission.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is"
* without express or implied warranty.
*/
#include "ares_setup.h"
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#ifdef HAVE_NETDB_H
# include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
# include <arpa/inet.h>
#endif
#include "ares.h"
#include "ares_inet_net_pton.h"
#include "ares_nowarn.h"
#include "ares_private.h"
#define MAX_ALIASES 40
int ares__readaddrinfo(FILE *fp,
const char *name,
unsigned short port,
const struct ares_addrinfo_hints *hints,
struct ares_addrinfo *ai)
{
char *line = NULL, *p, *q;
char *txtaddr, *txthost, *txtalias;
char *aliases[MAX_ALIASES];
unsigned int i, alias_count;
int status = ARES_SUCCESS;
size_t linesize;
struct ares_addrinfo_cname *cname = NULL, *cnames = NULL;
struct ares_addrinfo_node *nodes = NULL;
int match_with_alias, match_with_canonical;
int want_cname = hints->ai_flags & ARES_AI_CANONNAME;
/* Validate family */
switch (hints->ai_family) {
case AF_INET:
case AF_INET6:
case AF_UNSPEC:
break;
default:
return ARES_EBADFAMILY;
}
ai->name = ares_strdup(name);
if(!ai->name)
{
status = ARES_ENOMEM;
goto fail;
}
while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
{
match_with_alias = 0;
match_with_canonical = 0;
alias_count = 0;
/* Trim line comment. */
p = line;
while (*p && (*p != '#'))
p++;
*p = '\0';
/* Trim trailing whitespace. */
q = p - 1;
while ((q >= line) && ISSPACE(*q))
q--;
*++q = '\0';
/* Skip leading whitespace. */
p = line;
while (*p && ISSPACE(*p))
p++;
if (!*p)
/* Ignore line if empty. */
continue;
/* Pointer to start of IPv4 or IPv6 address part. */
txtaddr = p;
/* Advance past address part. */
while (*p && !ISSPACE(*p))
p++;
if (!*p)
/* Ignore line if reached end of line. */
continue;
/* Null terminate address part. */
*p = '\0';
/* Advance to host name */
p++;
while (*p && ISSPACE(*p))
p++;
if (!*p)
/* Ignore line if reached end of line. */
continue; /* LCOV_EXCL_LINE: trailing whitespace already stripped */
/* Pointer to start of host name. */
txthost = p;
/* Advance past host name. */
while (*p && !ISSPACE(*p))
p++;
/* Pointer to start of first alias. */
txtalias = NULL;
if (*p)
{
q = p + 1;
while (*q && ISSPACE(*q))
q++;
if (*q)
txtalias = q;
}
/* Null terminate host name. */
*p = '\0';
/* Find out if host name matches with canonical host name. */
if (strcasecmp(txthost, name) == 0)
{
match_with_canonical = 1;
}
/* Find out if host name matches with one of the aliases. */
while (txtalias)
{
p = txtalias;
while (*p && !ISSPACE(*p))
p++;
q = p;
while (*q && ISSPACE(*q))
q++;
*p = '\0';
if (strcasecmp(txtalias, name) == 0)
{
match_with_alias = 1;
if (!want_cname)
break;
}
if (alias_count < MAX_ALIASES)
{
aliases[alias_count++] = txtalias;
}
txtalias = *q ? q : NULL;
}
/* Try next line if host does not match. */
if (!match_with_alias && !match_with_canonical)
{
continue;
}
/*
* Convert address string to network address for the requested families.
* Actual address family possible values are AF_INET and AF_INET6 only.
*/
if ((hints->ai_family == AF_INET) || (hints->ai_family == AF_UNSPEC))
{
struct in_addr addr4;
if (ares_inet_pton(AF_INET, txtaddr, &addr4) == 1)
{
status = ares_append_ai_node(AF_INET, port, 0, &addr4, &nodes);
if (status != ARES_SUCCESS)
{
goto fail;
}
}
}
if ((hints->ai_family == AF_INET6) || (hints->ai_family == AF_UNSPEC))
{
struct ares_in6_addr addr6;
if (ares_inet_pton(AF_INET6, txtaddr, &addr6) == 1)
{
status = ares_append_ai_node(AF_INET6, port, 0, &addr6, &nodes);
if (status != ARES_SUCCESS)
{
goto fail;
}
}
}
if (status != ARES_SUCCESS)
/* Ignore line if invalid address string for the requested family. */
continue;
if (want_cname)
{
for (i = 0; i < alias_count; ++i)
{
cname = ares__append_addrinfo_cname(&cnames);
if (!cname)
{
status = ARES_ENOMEM;
goto fail;
}
cname->alias = ares_strdup(aliases[i]);
cname->name = ares_strdup(txthost);
}
/* No aliases, cname only. */
if(!alias_count)
{
cname = ares__append_addrinfo_cname(&cnames);
if (!cname)
{
status = ARES_ENOMEM;
goto fail;
}
cname->name = ares_strdup(txthost);
}
}
}
/* Last read failed. */
if (status == ARES_ENOMEM)
{
goto fail;
}
/* Free line buffer. */
ares_free(line);
ares__addrinfo_cat_cnames(&ai->cnames, cnames);
ares__addrinfo_cat_nodes(&ai->nodes, nodes);
return nodes ? ARES_SUCCESS : ARES_ENOTFOUND;
fail:
ares_free(line);
ares__freeaddrinfo_cnames(cnames);
ares__freeaddrinfo_nodes(nodes);
ares_free(ai->name);
ai->name = NULL;
return status;
}