BadVPN – Rev 1
?pathlinks?
/**
* @file
* NetBIOS name service responder
*/
/**
* @defgroup netbiosns NETBIOS responder
* @ingroup apps
*
* This is an example implementation of a NetBIOS name server.
* It responds to name queries for a configurable name.
* Name resolving is not supported.
*
* Note that the device doesn't broadcast it's own name so can't
* detect duplicate names!
*/
/*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* This file is part of the lwIP TCP/IP stack.
*
*/
#include "lwip/apps/netbiosns.h"
#if LWIP_IPV4 && LWIP_UDP /* don't build if not configured for use in lwipopts.h */
#include "lwip/def.h"
#include "lwip/udp.h"
#include "lwip/netif.h"
#include "lwip/prot/iana.h"
#include <string.h>
/** size of a NetBIOS name */
#define NETBIOS_NAME_LEN 16
/** The Time-To-Live for NetBIOS name responds (in seconds)
* Default is 300000 seconds (3 days, 11 hours, 20 minutes) */
#define NETBIOS_NAME_TTL 300000u
/** NetBIOS header flags */
#define NETB_HFLAG_RESPONSE 0x8000U
#define NETB_HFLAG_OPCODE 0x7800U
#define NETB_HFLAG_OPCODE_NAME_QUERY 0x0000U
#define NETB_HFLAG_AUTHORATIVE 0x0400U
#define NETB_HFLAG_TRUNCATED 0x0200U
#define NETB_HFLAG_RECURS_DESIRED 0x0100U
#define NETB_HFLAG_RECURS_AVAILABLE 0x0080U
#define NETB_HFLAG_BROADCAST 0x0010U
#define NETB_HFLAG_REPLYCODE 0x0008U
#define NETB_HFLAG_REPLYCODE_NOERROR 0x0000U
/** NetBIOS name flags */
#define NETB_NFLAG_UNIQUE 0x8000U
#define NETB_NFLAG_NODETYPE 0x6000U
#define NETB_NFLAG_NODETYPE_HNODE 0x6000U
#define NETB_NFLAG_NODETYPE_MNODE 0x4000U
#define NETB_NFLAG_NODETYPE_PNODE 0x2000U
#define NETB_NFLAG_NODETYPE_BNODE 0x0000U
/** NetBIOS message header */
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/bpstruct.h"
#endif
PACK_STRUCT_BEGIN
struct netbios_hdr {
PACK_STRUCT_FIELD(u16_t trans_id);
PACK_STRUCT_FIELD(u16_t flags);
PACK_STRUCT_FIELD(u16_t questions);
PACK_STRUCT_FIELD(u16_t answerRRs);
PACK_STRUCT_FIELD(u16_t authorityRRs);
PACK_STRUCT_FIELD(u16_t additionalRRs);
} PACK_STRUCT_STRUCT;
PACK_STRUCT_END
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/epstruct.h"
#endif
/** NetBIOS message name part */
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/bpstruct.h"
#endif
PACK_STRUCT_BEGIN
struct netbios_name_hdr {
PACK_STRUCT_FLD_8(u8_t nametype);
PACK_STRUCT_FLD_8(u8_t encname[(NETBIOS_NAME_LEN * 2) + 1]);
PACK_STRUCT_FIELD(u16_t type);
PACK_STRUCT_FIELD(u16_t cls);
PACK_STRUCT_FIELD(u32_t ttl);
PACK_STRUCT_FIELD(u16_t datalen);
PACK_STRUCT_FIELD(u16_t flags);
PACK_STRUCT_FLD_S(ip4_addr_p_t addr);
} PACK_STRUCT_STRUCT;
PACK_STRUCT_END
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/epstruct.h"
#endif
/** NetBIOS message */
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/bpstruct.h"
#endif
PACK_STRUCT_BEGIN
struct netbios_resp {
struct netbios_hdr resp_hdr;
struct netbios_name_hdr resp_name;
} PACK_STRUCT_STRUCT;
PACK_STRUCT_END
#ifdef PACK_STRUCT_USE_INCLUDES
# include "arch/epstruct.h"
#endif
#ifdef NETBIOS_LWIP_NAME
#define NETBIOS_LOCAL_NAME NETBIOS_LWIP_NAME
#else
static char netbiosns_local_name[NETBIOS_NAME_LEN];
#define NETBIOS_LOCAL_NAME netbiosns_local_name
#endif
struct udp_pcb *netbiosns_pcb;
/** Decode a NetBIOS name (from packet to string) */
static int
netbiosns_name_decode(char *name_enc, char *name_dec, int name_dec_len)
{
char *pname;
char cname;
char cnbname;
int idx = 0;
LWIP_UNUSED_ARG(name_dec_len);
/* Start decoding netbios name. */
pname = name_enc;
for (;;) {
/* Every two characters of the first level-encoded name
* turn into one character in the decoded name. */
cname = *pname;
if (cname == '\0') {
break; /* no more characters */
}
if (cname == '.') {
break; /* scope ID follows */
}
if (cname < 'A' || cname > 'Z') {
/* Not legal. */
return -1;
}
cname -= 'A';
cnbname = cname << 4;
pname++;
cname = *pname;
if (cname == '\0' || cname == '.') {
/* No more characters in the name - but we're in
* the middle of a pair. Not legal. */
return -1;
}
if (cname < 'A' || cname > 'Z') {
/* Not legal. */
return -1;
}
cname -= 'A';
cnbname |= cname;
pname++;
/* Do we have room to store the character? */
if (idx < NETBIOS_NAME_LEN) {
/* Yes - store the character. */
name_dec[idx++] = (cnbname != ' ' ? cnbname : '\0');
}
}
return 0;
}
#if 0 /* function currently unused */
/** Encode a NetBIOS name (from string to packet) - currently unused because
we don't ask for names. */
static int
netbiosns_name_encode(char *name_enc, char *name_dec, int name_dec_len)
{
char *pname;
char cname;
unsigned char ucname;
int idx = 0;
/* Start encoding netbios name. */
pname = name_enc;
for (;;) {
/* Every two characters of the first level-encoded name
* turn into one character in the decoded name. */
cname = *pname;
if (cname == '\0') {
break; /* no more characters */
}
if (cname == '.') {
break; /* scope ID follows */
}
if ((cname < 'A' || cname > 'Z') && (cname < '0' || cname > '9')) {
/* Not legal. */
return -1;
}
/* Do we have room to store the character? */
if (idx >= name_dec_len) {
return -1;
}
/* Yes - store the character. */
ucname = cname;
name_dec[idx++] = ('A' + ((ucname >> 4) & 0x0F));
name_dec[idx++] = ('A' + ( ucname & 0x0F));
pname++;
}
/* Fill with "space" coding */
for (; idx < name_dec_len - 1;) {
name_dec[idx++] = 'C';
name_dec[idx++] = 'A';
}
/* Terminate string */
name_dec[idx] = '\0';
return 0;
}
#endif /* 0 */
/** NetBIOS Name service recv callback */
static void
netbiosns_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
{
LWIP_UNUSED_ARG(arg);
/* if packet is valid */
if (p != NULL) {
char netbios_name[NETBIOS_NAME_LEN + 1];
struct netbios_hdr *netbios_hdr = (struct netbios_hdr *)p->payload;
struct netbios_name_hdr *netbios_name_hdr = (struct netbios_name_hdr *)(netbios_hdr + 1);
/* we only answer if we got a default interface */
if (netif_default != NULL) {
/* @todo: do we need to check answerRRs/authorityRRs/additionalRRs? */
/* if the packet is a NetBIOS name query question */
if (((netbios_hdr->flags & PP_NTOHS(NETB_HFLAG_OPCODE)) == PP_NTOHS(NETB_HFLAG_OPCODE_NAME_QUERY)) &&
((netbios_hdr->flags & PP_NTOHS(NETB_HFLAG_RESPONSE)) == 0) &&
(netbios_hdr->questions == PP_NTOHS(1))) {
/* decode the NetBIOS name */
netbiosns_name_decode((char *)(netbios_name_hdr->encname), netbios_name, sizeof(netbios_name));
/* if the packet is for us */
if (lwip_strnicmp(netbios_name, NETBIOS_LOCAL_NAME, sizeof(NETBIOS_LOCAL_NAME)) == 0) {
struct pbuf *q;
struct netbios_resp *resp;
q = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct netbios_resp), PBUF_RAM);
if (q != NULL) {
resp = (struct netbios_resp *)q->payload;
/* prepare NetBIOS header response */
resp->resp_hdr.trans_id = netbios_hdr->trans_id;
resp->resp_hdr.flags = PP_HTONS(NETB_HFLAG_RESPONSE |
NETB_HFLAG_OPCODE_NAME_QUERY |
NETB_HFLAG_AUTHORATIVE |
NETB_HFLAG_RECURS_DESIRED);
resp->resp_hdr.questions = 0;
resp->resp_hdr.answerRRs = PP_HTONS(1);
resp->resp_hdr.authorityRRs = 0;
resp->resp_hdr.additionalRRs = 0;
/* prepare NetBIOS header datas */
MEMCPY( resp->resp_name.encname, netbios_name_hdr->encname, sizeof(netbios_name_hdr->encname));
resp->resp_name.nametype = netbios_name_hdr->nametype;
resp->resp_name.type = netbios_name_hdr->type;
resp->resp_name.cls = netbios_name_hdr->cls;
resp->resp_name.ttl = PP_HTONL(NETBIOS_NAME_TTL);
resp->resp_name.datalen = PP_HTONS(sizeof(resp->resp_name.flags) + sizeof(resp->resp_name.addr));
resp->resp_name.flags = PP_HTONS(NETB_NFLAG_NODETYPE_BNODE);
ip4_addr_copy(resp->resp_name.addr, *netif_ip4_addr(netif_default));
/* send the NetBIOS response */
udp_sendto(upcb, q, addr, port);
/* free the "reference" pbuf */
pbuf_free(q);
}
}
}
}
/* free the pbuf */
pbuf_free(p);
}
}
/**
* @ingroup netbiosns
* Init netbios responder
*/
void
netbiosns_init(void)
{
#ifdef NETBIOS_LWIP_NAME
LWIP_ASSERT("NetBIOS name is too long!", strlen(NETBIOS_LWIP_NAME) < NETBIOS_NAME_LEN);
#endif
netbiosns_pcb = udp_new_ip_type(IPADDR_TYPE_ANY);
if (netbiosns_pcb != NULL) {
/* we have to be allowed to send broadcast packets! */
ip_set_option(netbiosns_pcb, SOF_BROADCAST);
udp_bind(netbiosns_pcb, IP_ANY_TYPE, LWIP_IANA_PORT_NETBIOS);
udp_recv(netbiosns_pcb, netbiosns_recv, netbiosns_pcb);
}
}
#ifndef NETBIOS_LWIP_NAME
/**
* @ingroup netbiosns
* Set netbios name. ATTENTION: the hostname must be less than 15 characters!
*/
void
netbiosns_set_name(const char *hostname)
{
size_t copy_len = strlen(hostname);
LWIP_ASSERT("NetBIOS name is too long!", copy_len < NETBIOS_NAME_LEN);
if (copy_len >= NETBIOS_NAME_LEN) {
copy_len = NETBIOS_NAME_LEN - 1;
}
MEMCPY(netbiosns_local_name, hostname, copy_len + 1);
}
#endif
/**
* @ingroup netbiosns
* Stop netbios responder
*/
void
netbiosns_stop(void)
{
if (netbiosns_pcb != NULL) {
udp_remove(netbiosns_pcb);
netbiosns_pcb = NULL;
}
}
#endif /* LWIP_IPV4 && LWIP_UDP */