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samba-mirror/libcli/dns/dns_hosts_file.c

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/*
Unix SMB/CIFS implementation.
read a file containing DNS names, types and IP addresses
Copyright (C) Andrew Tridgell 1994-1998
Copyright (C) Jeremy Allison 2007
Copyright (C) Andrew Bartlett 2009-2011
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/* The purpose of this file is to read the file generated by the samba_dnsupdate script */
#include "includes.h"
#include "lib/util/xfile.h"
#include "lib/util/util_net.h"
#include "system/filesys.h"
#include "system/network.h"
#include "libcli/nbt/libnbt.h"
#include "libcli/dns/dns.h"
#ifdef strcasecmp
#undef strcasecmp
#endif
/********************************************************
Start parsing the dns_hosts_file file.
*********************************************************/
static XFILE *startdns_hosts_file(const char *fname)
{
XFILE *fp = x_fopen(fname,O_RDONLY, 0);
if (!fp) {
DEBUG(4,("startdns_hosts_file: Can't open dns_hosts_file file %s. "
"Error was %s\n",
fname, strerror(errno)));
return NULL;
}
return fp;
}
/********************************************************
Parse the next line in the dns_hosts_file file.
*********************************************************/
static bool getdns_hosts_fileent(TALLOC_CTX *ctx, XFILE *fp, char **pp_name, char **pp_name_type,
char **pp_next_name,
struct sockaddr_storage *pss, uint32_t *p_port)
{
char line[1024];
*pp_name = NULL;
*pp_name_type = NULL;
*pp_next_name = NULL;
*p_port = 0;
while(!x_feof(fp) && !x_ferror(fp)) {
char *name_type = NULL;
char *name = NULL;
char *next_name = NULL;
char *ip = NULL;
char *port = NULL;
const char *ptr;
int count = 0;
if (!fgets_slash(line,sizeof(line),fp)) {
continue;
}
if (*line == '#') {
continue;
}
ptr = line;
if (next_token_talloc(ctx, &ptr, &name_type, NULL))
++count;
if (next_token_talloc(ctx, &ptr, &name, NULL))
++count;
if (name_type && strcasecmp(name_type, "A") == 0) {
if (next_token_talloc(ctx, &ptr, &ip, NULL))
++count;
} else if (name_type && strcasecmp(name_type, "SRV") == 0) {
if (next_token_talloc(ctx, &ptr, &next_name, NULL))
++count;
if (next_token_talloc(ctx, &ptr, &port, NULL))
++count;
} else if (name_type && strcasecmp(name_type, "CNAME") == 0) {
if (next_token_talloc(ctx, &ptr, &next_name, NULL))
++count;
}
if (count <= 0)
continue;
if (strcasecmp(name_type, "A") == 0) {
if (count != 3) {
DEBUG(0,("getdns_hosts_fileent: Ill formed hosts A record [%s]\n",
line));
continue;
}
DEBUG(4, ("getdns_hosts_fileent: host entry: %s %s %s\n",
name_type, name, ip));
if (!interpret_string_addr(pss, ip, AI_NUMERICHOST)) {
DEBUG(0,("getdns_hosts_fileent: invalid address "
"%s.\n", ip));
}
} else if (strcasecmp(name_type, "SRV") == 0) {
if (count != 4) {
DEBUG(0,("getdns_hosts_fileent: Ill formed hosts SRV record [%s]\n",
line));
continue;
}
*p_port = strtoul(port, NULL, 10);
if (*p_port == UINT32_MAX) {
DEBUG(0, ("getdns_hosts_fileent: Ill formed hosts SRV record [%s] (invalid port: %s)\n",
line, port));
continue;
}
DEBUG(4, ("getdns_hosts_fileent: host entry: %s %s %s %u\n",
name_type, name, next_name, (unsigned int)*p_port));
*pp_next_name = talloc_strdup(ctx, next_name);
if (!*pp_next_name) {
return false;
}
} else if (strcasecmp(name_type, "CNAME") == 0) {
if (count != 3) {
DEBUG(0,("getdns_hosts_fileent: Ill formed hosts CNAME record [%s]\n",
line));
continue;
}
DEBUG(4, ("getdns_hosts_fileent: host entry: %s %s %s\n",
name_type, name, next_name));
*pp_next_name = talloc_strdup(ctx, next_name);
if (!*pp_next_name) {
return false;
}
} else {
DEBUG(0,("getdns_hosts_fileent: unknown type %s\n", name_type));
continue;
}
*pp_name = talloc_strdup(ctx, name);
if (!*pp_name) {
return false;
}
*pp_name_type = talloc_strdup(ctx, name_type);
if (!*pp_name_type) {
return false;
}
return true;
}
return false;
}
/********************************************************
Finish parsing the dns_hosts_file file.
*********************************************************/
static void enddns_hosts_file(XFILE *fp)
{
x_fclose(fp);
}
/********************************************************
Resolve via "dns_hosts" method.
*********************************************************/
static NTSTATUS resolve_dns_hosts_file_as_dns_rr_recurse(const char *dns_hosts_file,
const char *name, bool srv_lookup,
int level, uint32_t port,
TALLOC_CTX *mem_ctx,
struct dns_rr_srv **return_rr,
int *return_count)
{
/*
* "dns_hosts" means parse the local dns_hosts file.
*/
XFILE *fp;
char *host_name = NULL;
char *name_type = NULL;
char *next_name = NULL;
struct sockaddr_storage return_ss;
uint32_t srv_port;
NTSTATUS status = NT_STATUS_OBJECT_NAME_NOT_FOUND;
TALLOC_CTX *ctx = NULL;
TALLOC_CTX *ip_list_ctx = NULL;
struct dns_rr_srv *rr = NULL;
*return_rr = NULL;
/* Don't recurse forever, even on our own flat files */
if (level > 11) {
DEBUG(0, ("resolve_dns_hosts_file recursion limit reached looking up %s!\n", name));
return status;
}
*return_count = 0;
DEBUG(3,("resolve_dns_hosts: (%d) "
"Attempting %s dns_hosts lookup for name %s\n",
level, srv_lookup ? "SRV" : "A", name));
fp = startdns_hosts_file(dns_hosts_file);
if ( fp == NULL )
return NT_STATUS_OBJECT_NAME_NOT_FOUND;
ip_list_ctx = talloc_new(mem_ctx);
if (!ip_list_ctx) {
enddns_hosts_file(fp);
return NT_STATUS_NO_MEMORY;
}
ctx = talloc_new(ip_list_ctx);
if (!ctx) {
talloc_free(ip_list_ctx);
enddns_hosts_file(fp);
return NT_STATUS_NO_MEMORY;
}
while (getdns_hosts_fileent(ctx, fp, &host_name, &name_type, &next_name, &return_ss, &srv_port)) {
if (!strequal(name, host_name)) {
/* continue at the bottom of the loop */
} else if (srv_lookup) {
if (strcasecmp(name_type, "SRV") == 0) {
NTSTATUS status_recurse;
struct dns_rr_srv *tmp_rr;
int tmp_count = 0;
/* we only accept one host name per SRV entry */
status_recurse
= resolve_dns_hosts_file_as_dns_rr_recurse(dns_hosts_file, next_name,
false,
level + 1, srv_port,
ip_list_ctx, &tmp_rr,
&tmp_count);
if (NT_STATUS_EQUAL(status_recurse, NT_STATUS_OBJECT_NAME_NOT_FOUND)) {
/* Don't fail on a dangling SRV record */
} else if (!NT_STATUS_IS_OK(status_recurse)) {
enddns_hosts_file(fp);
talloc_free(ip_list_ctx);
return status_recurse;
} else if (tmp_count != 1) {
status = NT_STATUS_OBJECT_NAME_NOT_FOUND;
} else {
status = status_recurse;
rr = talloc_realloc(ip_list_ctx, rr, struct dns_rr_srv, (*return_count) + 1);
if (!rr) {
enddns_hosts_file(fp);
return NT_STATUS_NO_MEMORY;
}
talloc_steal(rr, tmp_rr);
rr[*return_count] = *tmp_rr;
*return_count = (*return_count) + 1;
}
}
} else if (strcasecmp(name_type, "CNAME") == 0) {
/* we only accept one host name per CNAME */
enddns_hosts_file(fp);
status = resolve_dns_hosts_file_as_dns_rr_recurse(dns_hosts_file, next_name, false,
level + 1, port,
mem_ctx, return_rr, return_count);
talloc_free(ip_list_ctx);
return status;
} else if (strcasecmp(name_type, "A") == 0) {
if (*return_count == 0) {
/* We are happy to keep looking for other possible A record matches */
rr = talloc_zero(ip_list_ctx,
struct dns_rr_srv);
if (rr == NULL) {
TALLOC_FREE(ctx);
enddns_hosts_file(fp);
DEBUG(3,("resolve_dns_hosts: talloc_realloc fail !\n"));
return NT_STATUS_NO_MEMORY;
}
rr->hostname = talloc_strdup(rr, host_name);
if (rr->hostname == NULL) {
TALLOC_FREE(ctx);
enddns_hosts_file(fp);
DEBUG(3,("resolve_dns_hosts: talloc_realloc fail !\n"));
return NT_STATUS_NO_MEMORY;
}
rr->port = port;
*return_count = 1;
}
/* Set the specified port (possibly from a SRV lookup) into the structure we return */
set_sockaddr_port((struct sockaddr *)&return_ss, port);
/* We are happy to keep looking for other possible A record matches */
rr->ss_s = talloc_realloc(rr, rr->ss_s,
struct sockaddr_storage,
rr->num_ips + 1);
if (rr->ss_s == NULL) {
TALLOC_FREE(ctx);
enddns_hosts_file(fp);
DEBUG(3,("resolve_dns_hosts: talloc_realloc fail !\n"));
return NT_STATUS_NO_MEMORY;
}
rr->ss_s[rr->num_ips] = return_ss;
rr->num_ips += 1;
/* we found something */
status = NT_STATUS_OK;
}
TALLOC_FREE(ctx);
ctx = talloc_new(mem_ctx);
if (!ctx) {
enddns_hosts_file(fp);
return NT_STATUS_NO_MEMORY;
}
}
*return_rr = talloc_steal(mem_ctx, rr);
TALLOC_FREE(ip_list_ctx);
enddns_hosts_file(fp);
return status;
}
/********************************************************
Resolve via "dns_hosts_file" method, returning a list of sockaddr_storage values
*********************************************************/
NTSTATUS resolve_dns_hosts_file_as_sockaddr(const char *dns_hosts_file,
const char *name, bool srv_lookup,
TALLOC_CTX *mem_ctx,
struct sockaddr_storage **return_iplist,
int *return_count)
{
NTSTATUS status;
struct dns_rr_srv *dns_rr = NULL;
int i, j, rr_count = 0;
*return_iplist = NULL;
*return_count = 0;
status = resolve_dns_hosts_file_as_dns_rr_recurse(dns_hosts_file, name, srv_lookup,
0, 0,
mem_ctx, &dns_rr, &rr_count);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(3,("resolve_dns_hosts (sockaddr): "
"failed to obtain %s result records for for name %s: %s\n",
srv_lookup ? "SRV" : "A", name, nt_errstr(status)));
return status;
}
for (i=0; i < rr_count; i++) {
*return_iplist = talloc_realloc(mem_ctx, *return_iplist, struct sockaddr_storage, *return_count + dns_rr[i].num_ips);
if (!*return_iplist) {
return NT_STATUS_NO_MEMORY;
}
for (j=0; j < dns_rr[i].num_ips; j++) {
(*return_iplist)[*return_count] = dns_rr[i].ss_s[j];
*return_count = *return_count + 1;
}
}
DEBUG(3,("resolve_dns_hosts (sockaddr): "
"Found %d results for for name %s\n",
*return_count, name));
return NT_STATUS_OK;
}
/********************************************************
Resolve via "dns_hosts_file" method, returning struct dns_rr_srv
*********************************************************/
NTSTATUS resolve_dns_hosts_file_as_dns_rr(const char *dns_hosts_file,
const char *name, bool srv_lookup,
TALLOC_CTX *mem_ctx,
struct dns_rr_srv **return_rr,
int *return_count)
{
NTSTATUS status;
*return_rr = NULL;
*return_count = 0;
status = resolve_dns_hosts_file_as_dns_rr_recurse(dns_hosts_file, name, srv_lookup,
0, 0,
mem_ctx, return_rr, return_count);
if (NT_STATUS_IS_OK(status)) {
DEBUG(3,("resolve_dns_hosts (dns_rr): "
"Found %d %s result records for for name %s\n",
*return_count, srv_lookup ? "SRV" : "A", name));
} else {
DEBUG(3,("resolve_dns_hosts (dns_rr): "
"failed to obtain %s result records for for name %s: %s\n",
srv_lookup ? "SRV" : "A", name, nt_errstr(status)));
}
return status;
}