source: vendor/3.6.0/source4/libcli/resolve/file.c

/* 
   Unix SMB/CIFS implementation.

   broadcast name resolution module

   Copyright (C) Andrew Tridgell 1994-1998,2005
   Copyright (C) Jeremy Allison 2007
   Copyright (C) Jelmer Vernooij 2007
   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2009-2010
   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/>.
*/

#include "includes.h"
#include "libcli/composite/composite.h"
#include "libcli/resolve/resolve.h"
#include "lib/socket/socket.h"
#include "system/network.h"
#include "lib/socket/netif.h"
#include "param/param.h"
#include "lib/util/util_net.h"
#include "libcli/nbt/libnbt.h"

struct resolve_file_data {
        const char *lookup_file;
        const char *default_domain;
};

struct resolve_file_state {
        struct socket_address **addrs;
        char **names;
};

/**
  broadcast name resolution method - async send
 */
/*
  general name resolution - async send
 */
struct composite_context *resolve_name_file_send(TALLOC_CTX *mem_ctx, 
                                                  struct tevent_context *event_ctx,
                                                  void *userdata, uint32_t flags,
                                                  uint16_t port,
                                                  struct nbt_name *name)
{
        struct composite_context *c;
        struct resolve_file_data *data = talloc_get_type_abort(userdata, struct resolve_file_data);
        struct resolve_file_state *state;
        struct sockaddr_storage *resolved_iplist;
        int resolved_count, i;
        const char *dns_name;

        bool srv_lookup = (flags & RESOLVE_NAME_FLAG_DNS_SRV);

        if (event_ctx == NULL) {
                return NULL;
        }

        c = composite_create(mem_ctx, event_ctx);
        if (c == NULL) return NULL;

        /* This isn't an NBT layer resolver */
        if (flags & RESOLVE_NAME_FLAG_FORCE_NBT) {
                composite_error(c, NT_STATUS_OBJECT_NAME_NOT_FOUND);
                return c;
        }

        if (composite_nomem(c->event_ctx, c)) return c;

        state = talloc_zero(c, struct resolve_file_state);
        if (composite_nomem(state, c)) return c;
        c->private_data = state;

        dns_name = name->name;
        if (strchr(dns_name, '.') == NULL) {
                dns_name = talloc_asprintf(state, "%s.%s", dns_name, data->default_domain);
        }

        c->status = resolve_dns_hosts_file_as_sockaddr(data->lookup_file, dns_name,
                                                       srv_lookup, state, &resolved_iplist, &resolved_count);
        if (!composite_is_ok(c)) return c;

        for (i=0; i < resolved_count; i++) {
                state->addrs = talloc_realloc(state, state->addrs, struct socket_address *, i+2);
                if (composite_nomem(state->addrs, c)) return c;
                
                if (!(flags & RESOLVE_NAME_FLAG_OVERWRITE_PORT)) {
                        set_sockaddr_port((struct sockaddr *)&resolved_iplist[i], port);
                }

                state->addrs[i] = socket_address_from_sockaddr(state->addrs, (struct sockaddr *)&resolved_iplist[i], sizeof(resolved_iplist[i]));
                if (composite_nomem(state->addrs[i], c)) return c;

                state->addrs[i+1] = NULL;


                state->names = talloc_realloc(state, state->names, char *, i+2);
                if (composite_nomem(state->addrs, c)) return c;

                state->names[i] = talloc_strdup(state->names, dns_name);
                if (composite_nomem(state->names[i], c)) return c;

                state->names[i+1] = NULL;
                
                i++;
        }

        composite_done(c);
        return c;
}

/*
  general name resolution method - recv side
 */
NTSTATUS resolve_name_file_recv(struct composite_context *c, 
                                 TALLOC_CTX *mem_ctx,
                                 struct socket_address ***addrs,
                                 char ***names)
{
        NTSTATUS status;

        status = composite_wait(c);

        if (NT_STATUS_IS_OK(status)) {
                struct resolve_file_state *state = talloc_get_type(c->private_data, struct resolve_file_state);
                *addrs = talloc_steal(mem_ctx, state->addrs);
                if (names) {
                        *names = talloc_steal(mem_ctx, state->names);
                }
        }

        talloc_free(c);
        return status;
}


bool resolve_context_add_file_method(struct resolve_context *ctx, const char *lookup_file, const char *default_domain)
{
        struct resolve_file_data *data = talloc(ctx, struct resolve_file_data);
        data->lookup_file    = talloc_strdup(data, lookup_file);
        data->default_domain = talloc_strdup(data, default_domain);
        return resolve_context_add_method(ctx, resolve_name_file_send, resolve_name_file_recv, data);
}

bool resolve_context_add_file_method_lp(struct resolve_context *ctx, struct loadparm_context *lp_ctx)
{
        return resolve_context_add_file_method(ctx,
                                               lpcfg_parm_string(lp_ctx, NULL, "resolv", "host file"),
                                               lpcfg_dnsdomain(lp_ctx));
}