/** * @file * NetBIOS name service sample * */ /* * 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/opt.h" #if LWIP_UDP /* don't build if not configured for use in lwipopts.h */ #include "lwip/udp.h" #include "lwip/netif.h" #include /** 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! */ /** NetBIOS name of LWIP device * This must be uppercase until NETBIOS_STRCMP() is defined to a string * comparision function that is case insensitive. * If you want to use the netif's hostname, use this (with LWIP_NETIF_HOSTNAME): * (ip_current_netif() != NULL ? ip_current_netif()->hostname != NULL ? ip_current_netif()->hostname : "" : "") */ #ifndef NETBIOS_LWIP_NAME #define NETBIOS_LWIP_NAME "NETBIOSLWIPDEV" #endif /** Since there's no standard function for case-insensitive string comparision, * we need another define here: * define this to stricmp() for windows or strcasecmp() for linux. * If not defined, comparision is case sensitive and NETBIOS_LWIP_NAME must be * uppercase */ #ifndef NETBIOS_STRCMP #define NETBIOS_STRCMP(str1, str2) strcmp(str1, str2) #endif /** default port number for "NetBIOS Name service */ #define NETBIOS_PORT 137 /** 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 300000 /** 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(ip_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 /** NetBIOS decoding name */ static int netbios_name_decoding( 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 */ /** NetBIOS encoding name */ static int netbios_name_encoding(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 netbios_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, 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 */ netbios_name_decoding( (char*)(netbios_name_hdr->encname), netbios_name, sizeof(netbios_name)); /* if the packet is for us */ if (NETBIOS_STRCMP(netbios_name, NETBIOS_LWIP_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); ip_addr_copy(resp->resp_name.addr, netif_default->ip_addr); /* send the NetBIOS response */ udp_sendto(upcb, q, addr, port); /* free the "reference" pbuf */ pbuf_free(q); } } } } /* free the pbuf */ pbuf_free(p); } } void netbios_init(void) { struct udp_pcb *pcb; LWIP_ASSERT("NetBIOS name is too long!", strlen(NETBIOS_LWIP_NAME) < NETBIOS_NAME_LEN); pcb = udp_new(); if (pcb != NULL) { /* we have to be allowed to send broadcast packets! */ pcb->so_options |= SOF_BROADCAST; udp_bind(pcb, IP_ADDR_ANY, NETBIOS_PORT); udp_recv(pcb, netbios_recv, pcb); } } #endif /* LWIP_UDP */