/* Unix SMB/Netbios implementation. Version 1.9. NBT netbios library routines Copyright (C) Andrew Tridgell 1994-1997 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 2 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, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "includes.h" extern int DEBUGLEVEL; int num_good_sends = 0; int num_good_receives = 0; extern pstring scope; extern pstring myname; extern struct in_addr ipzero; static struct opcode_names { char *nmb_opcode_name; int opcode; } nmb_header_opcode_names[] = { { "Query", 0 }, {"Registration", 5 }, {"Release", 6 }, {"WACK", 7 }, {"refresh", 8 }, {0, -1 } }; /**************************************************************************** * Lookup a nmb opcode name. ****************************************************************************/ char *lookup_opcode_name( int opcode ) { struct opcode_names *op_namep; int i; for(i = 0; nmb_header_opcode_names[i].nmb_opcode_name != 0; i++) { op_namep = &nmb_header_opcode_names[i]; if(opcode == op_namep->opcode) return op_namep->nmb_opcode_name; } return "<unknown opcode>"; } /**************************************************************************** print out a res_rec structure ****************************************************************************/ static void debug_nmb_res_rec(struct res_rec *res, char *hdr) { int i, j; DEBUG(4,(" %s: nmb_name=%s rr_type=%d rr_class=%d ttl=%d\n", hdr, namestr(&res->rr_name), res->rr_type, res->rr_class, res->ttl)); if (res->rdlength == 0 || res->rdata == NULL) return; for (i = 0; i < res->rdlength; i+= 16) { DEBUG(4, (" %s %3x char ", hdr, i)); for (j = 0; j < 16; j++) { unsigned char x = res->rdata[i+j]; if (x < 32 || x > 127) x = '.'; if (i+j >= res->rdlength) break; DEBUG(4, ("%c", x)); } DEBUG(4, (" hex ", i)); for (j = 0; j < 16; j++) { if (i+j >= res->rdlength) break; DEBUG(4, ("%02X", (unsigned char)res->rdata[i+j])); } DEBUG(4, ("\n")); } } /**************************************************************************** process a nmb packet ****************************************************************************/ void debug_nmb_packet(struct packet_struct *p) { struct nmb_packet *nmb = &p->packet.nmb; DEBUG(4,("nmb packet from %s header: id=%d opcode=%s(%d) response=%s\n", inet_ntoa(p->ip), nmb->header.name_trn_id, lookup_opcode_name(nmb->header.opcode), nmb->header.opcode,BOOLSTR(nmb->header.response))); DEBUG(4,(" header: flags: bcast=%s rec_avail=%s rec_des=%s trunc=%s auth=%s\n", BOOLSTR(nmb->header.nm_flags.bcast), BOOLSTR(nmb->header.nm_flags.recursion_available), BOOLSTR(nmb->header.nm_flags.recursion_desired), BOOLSTR(nmb->header.nm_flags.trunc), BOOLSTR(nmb->header.nm_flags.authoritative))); DEBUG(4,(" header: rcode=%d qdcount=%d ancount=%d nscount=%d arcount=%d\n", nmb->header.rcode, nmb->header.qdcount, nmb->header.ancount, nmb->header.nscount, nmb->header.arcount)); if (nmb->header.qdcount) { DEBUG(4,(" question: q_name=%s q_type=%d q_class=%d\n", namestr(&nmb->question.question_name), nmb->question.question_type, nmb->question.question_class)); } if (nmb->answers && nmb->header.ancount) { debug_nmb_res_rec(nmb->answers,"answers"); } if (nmb->nsrecs && nmb->header.nscount) { debug_nmb_res_rec(nmb->nsrecs,"nsrecs"); } if (nmb->additional && nmb->header.arcount) { debug_nmb_res_rec(nmb->additional,"additional"); } } /******************************************************************* handle "compressed" name pointers ******************************************************************/ static BOOL handle_name_ptrs(unsigned char *ubuf,int *offset,int length, BOOL *got_pointer,int *ret) { int loop_count=0; while ((ubuf[*offset] & 0xC0) == 0xC0) { if (!*got_pointer) (*ret) += 2; (*got_pointer)=True; (*offset) = ((ubuf[*offset] & ~0xC0)<<8) | ubuf[(*offset)+1]; if (loop_count++ == 10 || (*offset) < 0 || (*offset)>(length-2)) { return(False); } } return(True); } /******************************************************************* parse a nmb name from "compressed" format to something readable return the space taken by the name, or 0 if the name is invalid ******************************************************************/ static int parse_nmb_name(char *inbuf,int offset,int length, struct nmb_name *name) { int m,n=0; unsigned char *ubuf = (unsigned char *)inbuf; int ret = 0; BOOL got_pointer=False; if (length - offset < 2) return(0); /* handle initial name pointers */ if (!handle_name_ptrs(ubuf,&offset,length,&got_pointer,&ret)) return(0); m = ubuf[offset]; if (!m) return(0); if ((m & 0xC0) || offset+m+2 > length) return(0); bzero((char *)name,sizeof(*name)); /* the "compressed" part */ if (!got_pointer) ret += m + 2; offset++; while (m) { unsigned char c1,c2; c1 = ubuf[offset++]-'A'; c2 = ubuf[offset++]-'A'; if ((c1 & 0xF0) || (c2 & 0xF0)) return(0); name->name[n++] = (c1<<4) | c2; m -= 2; } name->name[n] = 0; if (n==16) { /* parse out the name type, its always in the 16th byte of the name */ name->name_type = name->name[15]; /* remove trailing spaces */ name->name[15] = 0; n = 14; while (n && name->name[n]==' ') name->name[n--] = 0; } /* now the domain parts (if any) */ n = 0; while ((m=ubuf[offset])) { /* we can have pointers within the domain part as well */ if (!handle_name_ptrs(ubuf,&offset,length,&got_pointer,&ret)) return(0); if (!got_pointer) ret += m+1; if (n) name->scope[n++] = '.'; if (m+2+offset>length || n+m+1>sizeof(name->scope)) return(0); offset++; while (m--) name->scope[n++] = (char)ubuf[offset++]; } name->scope[n++] = 0; return(ret); } /******************************************************************* put a compressed nmb name into a buffer. return the length of the compressed name compressed names are really weird. The "compression" doubles the size. The idea is that it also means that compressed names conform to the doman name system. See RFC1002. ******************************************************************/ static int put_nmb_name(char *buf,int offset,struct nmb_name *name) { int ret,m; fstring buf1; char *p; if (name->name[0] == '*') { /* special case for wildcard name */ bzero(buf1,20); buf1[0] = '*'; } else { sprintf(buf1,"%-15.15s%c",name->name,name->name_type); } buf[offset] = 0x20; ret = 34; for (m=0;m<16;m++) { buf[offset+1+2*m] = 'A' + ((buf1[m]>>4)&0xF); buf[offset+2+2*m] = 'A' + (buf1[m]&0xF); } offset += 33; buf[offset] = 0; if (name->scope[0]) { /* XXXX this scope handling needs testing */ ret += strlen(name->scope) + 1; strcpy(&buf[offset+1],name->scope); p = &buf[offset+1]; while ((p = strchr(p,'.'))) { buf[offset] = PTR_DIFF(p,&buf[offset]); offset += buf[offset]; p = &buf[offset+1]; } buf[offset] = strlen(&buf[offset+1]); } return(ret); } /******************************************************************* useful for debugging messages ******************************************************************/ char *namestr(struct nmb_name *n) { static int i=0; static fstring ret[4]; char *p = ret[i]; if (!n->scope[0]) sprintf(p,"%s(%x)",n->name,n->name_type); else sprintf(p,"%s(%x).%s",n->name,n->name_type,n->scope); i = (i+1)%4; return(p); } /******************************************************************* allocate and parse some resource records ******************************************************************/ static BOOL parse_alloc_res_rec(char *inbuf,int *offset,int length, struct res_rec **recs, int count) { int i; *recs = (struct res_rec *)malloc(sizeof(**recs)*count); if (!*recs) return(False); bzero(*recs,sizeof(**recs)*count); for (i=0;i<count;i++) { int l = parse_nmb_name(inbuf,*offset,length,&(*recs)[i].rr_name); (*offset) += l; if (!l || (*offset)+10 > length) { free(*recs); return(False); } (*recs)[i].rr_type = RSVAL(inbuf,(*offset)); (*recs)[i].rr_class = RSVAL(inbuf,(*offset)+2); (*recs)[i].ttl = RIVAL(inbuf,(*offset)+4); (*recs)[i].rdlength = RSVAL(inbuf,(*offset)+8); (*offset) += 10; if ((*recs)[i].rdlength>sizeof((*recs)[i].rdata) || (*offset)+(*recs)[i].rdlength > length) { free(*recs); return(False); } memcpy((*recs)[i].rdata,inbuf+(*offset),(*recs)[i].rdlength); (*offset) += (*recs)[i].rdlength; } return(True); } /******************************************************************* put a resource record into a packet ******************************************************************/ static int put_res_rec(char *buf,int offset,struct res_rec *recs,int count) { int ret=0; int i; for (i=0;i<count;i++) { int l = put_nmb_name(buf,offset,&recs[i].rr_name); offset += l; ret += l; RSSVAL(buf,offset,recs[i].rr_type); RSSVAL(buf,offset+2,recs[i].rr_class); RSIVAL(buf,offset+4,recs[i].ttl); RSSVAL(buf,offset+8,recs[i].rdlength); memcpy(buf+offset+10,recs[i].rdata,recs[i].rdlength); offset += 10+recs[i].rdlength; ret += 10+recs[i].rdlength; } return(ret); } /******************************************************************* parse a dgram packet. Return False if the packet can't be parsed or is invalid for some reason, True otherwise this is documented in section 4.4.1 of RFC1002 ******************************************************************/ static BOOL parse_dgram(char *inbuf,int length,struct dgram_packet *dgram) { int offset; int flags; bzero((char *)dgram,sizeof(*dgram)); if (length < 14) return(False); dgram->header.msg_type = CVAL(inbuf,0); flags = CVAL(inbuf,1); dgram->header.flags.node_type = (enum node_type)((flags>>2)&3); if (flags & 1) dgram->header.flags.more = True; if (flags & 2) dgram->header.flags.first = True; dgram->header.dgm_id = RSVAL(inbuf,2); putip((char *)&dgram->header.source_ip,inbuf+4); dgram->header.source_port = RSVAL(inbuf,8); dgram->header.dgm_length = RSVAL(inbuf,10); dgram->header.packet_offset = RSVAL(inbuf,12); offset = 14; if (dgram->header.msg_type == 0x10 || dgram->header.msg_type == 0x11 || dgram->header.msg_type == 0x12) { offset += parse_nmb_name(inbuf,offset,length,&dgram->source_name); offset += parse_nmb_name(inbuf,offset,length,&dgram->dest_name); } if (offset >= length || (length-offset > sizeof(dgram->data))) return(False); dgram->datasize = length-offset; memcpy(dgram->data,inbuf+offset,dgram->datasize); return(True); } /******************************************************************* parse a nmb packet. Return False if the packet can't be parsed or is invalid for some reason, True otherwise ******************************************************************/ static BOOL parse_nmb(char *inbuf,int length,struct nmb_packet *nmb) { int nm_flags,offset; bzero((char *)nmb,sizeof(*nmb)); if (length < 12) return(False); /* parse the header */ nmb->header.name_trn_id = RSVAL(inbuf,0); DEBUG(10,("parse_nmb: packet id = %d\n", nmb->header.name_trn_id)); nmb->header.opcode = (CVAL(inbuf,2) >> 3) & 0xF; nmb->header.response = ((CVAL(inbuf,2)>>7)&1)?True:False; nm_flags = ((CVAL(inbuf,2) & 0x7) << 4) + (CVAL(inbuf,3)>>4); nmb->header.nm_flags.bcast = (nm_flags&1)?True:False; nmb->header.nm_flags.recursion_available = (nm_flags&8)?True:False; nmb->header.nm_flags.recursion_desired = (nm_flags&0x10)?True:False; nmb->header.nm_flags.trunc = (nm_flags&0x20)?True:False; nmb->header.nm_flags.authoritative = (nm_flags&0x40)?True:False; nmb->header.rcode = CVAL(inbuf,3) & 0xF; nmb->header.qdcount = RSVAL(inbuf,4); nmb->header.ancount = RSVAL(inbuf,6); nmb->header.nscount = RSVAL(inbuf,8); nmb->header.arcount = RSVAL(inbuf,10); if (nmb->header.qdcount) { offset = parse_nmb_name(inbuf,12,length,&nmb->question.question_name); if (!offset) return(False); if (length - (12+offset) < 4) return(False); nmb->question.question_type = RSVAL(inbuf,12+offset); nmb->question.question_class = RSVAL(inbuf,12+offset+2); offset += 12+4; } else { offset = 12; } /* and any resource records */ if (nmb->header.ancount && !parse_alloc_res_rec(inbuf,&offset,length,&nmb->answers, nmb->header.ancount)) return(False); if (nmb->header.nscount && !parse_alloc_res_rec(inbuf,&offset,length,&nmb->nsrecs, nmb->header.nscount)) return(False); if (nmb->header.arcount && !parse_alloc_res_rec(inbuf,&offset,length,&nmb->additional, nmb->header.arcount)) return(False); return(True); } /******************************************************************* free up any resources associated with an nmb packet ******************************************************************/ void free_nmb_packet(struct nmb_packet *nmb) { if (nmb->answers) free(nmb->answers); if (nmb->nsrecs) free(nmb->nsrecs); if (nmb->additional) free(nmb->additional); } /******************************************************************* free up any resources associated with a packet ******************************************************************/ void free_packet(struct packet_struct *packet) { if (packet->packet_type == NMB_PACKET) free_nmb_packet(&packet->packet.nmb); free(packet); } /******************************************************************* read a packet from a socket and parse it, returning a packet ready to be used or put on the queue. This assumes a UDP socket ******************************************************************/ struct packet_struct *read_packet(int fd,enum packet_type packet_type) { extern struct in_addr lastip; extern int lastport; struct packet_struct *packet; char buf[MAX_DGRAM_SIZE]; int length; BOOL ok=False; length = read_udp_socket(fd,buf,sizeof(buf)); if (length < MIN_DGRAM_SIZE) return(NULL); packet = (struct packet_struct *)malloc(sizeof(*packet)); if (!packet) return(NULL); packet->next = NULL; packet->prev = NULL; packet->ip = lastip; packet->port = lastport; packet->fd = fd; packet->timestamp = time(NULL); packet->packet_type = packet_type; switch (packet_type) { case NMB_PACKET: ok = parse_nmb(buf,length,&packet->packet.nmb); break; case DGRAM_PACKET: ok = parse_dgram(buf,length,&packet->packet.dgram); break; } if (!ok) { DEBUG(10,("parse_nmb: discarding packet id = %d\n", packet->packet.nmb.header.name_trn_id)); free(packet); return(NULL); } num_good_receives++; DEBUG(5,("%s received a packet of len %d from (%s) port %d\n", timestring(),length,inet_ntoa(packet->ip),packet->port)); return(packet); } /******************************************************************* send a udp packet on a already open socket ******************************************************************/ static BOOL send_udp(int fd,char *buf,int len,struct in_addr ip,int port) { BOOL ret; struct sockaddr_in sock_out; /* set the address and port */ bzero((char *)&sock_out,sizeof(sock_out)); putip((char *)&sock_out.sin_addr,(char *)&ip); sock_out.sin_port = htons( port ); sock_out.sin_family = AF_INET; DEBUG(5,("%s sending a packet of len %d to (%s) on port %d\n", timestring(),len,inet_ntoa(ip),port)); ret = (sendto(fd,buf,len,0,(struct sockaddr *)&sock_out, sizeof(sock_out)) >= 0); if (!ret) DEBUG(0,("Packet send failed to %s(%d) ERRNO=%s\n", inet_ntoa(ip),port,strerror(errno))); if (ret) num_good_sends++; return(ret); } /******************************************************************* build a dgram packet ready for sending XXXX This currently doesn't handle packets too big for one datagram. It should split them and use the packet_offset, more and first flags to handle the fragmentation. Yuck. ******************************************************************/ static int build_dgram(char *buf,struct packet_struct *p) { struct dgram_packet *dgram = &p->packet.dgram; unsigned char *ubuf = (unsigned char *)buf; int offset=0; /* put in the header */ ubuf[0] = dgram->header.msg_type; ubuf[1] = (((int)dgram->header.flags.node_type)<<2); if (dgram->header.flags.more) ubuf[1] |= 1; if (dgram->header.flags.first) ubuf[1] |= 2; RSSVAL(ubuf,2,dgram->header.dgm_id); putip(ubuf+4,(char *)&dgram->header.source_ip); RSSVAL(ubuf,8,dgram->header.source_port); RSSVAL(ubuf,12,dgram->header.packet_offset); offset = 14; if (dgram->header.msg_type == 0x10 || dgram->header.msg_type == 0x11 || dgram->header.msg_type == 0x12) { offset += put_nmb_name((char *)ubuf,offset,&dgram->source_name); offset += put_nmb_name((char *)ubuf,offset,&dgram->dest_name); } memcpy(ubuf+offset,dgram->data,dgram->datasize); offset += dgram->datasize; /* automatically set the dgm_length */ dgram->header.dgm_length = offset; RSSVAL(ubuf,10,dgram->header.dgm_length); return(offset); } /******************************************************************* build a nmb name ******************************************************************/ void make_nmb_name(struct nmb_name *n,char *name,int type,char *this_scope) { fstrcpy(n->name,name); strupper(n->name); n->name_type = type; fstrcpy(n->scope,this_scope); } /******************************************************************* build a nmb packet ready for sending XXXX this currently relies on not being passed something that expands to a packet too big for the buffer. Eventually this should be changed to set the trunc bit so the receiver can request the rest via tcp (when that becomes supported) ******************************************************************/ static int build_nmb(char *buf,struct packet_struct *p) { struct nmb_packet *nmb = &p->packet.nmb; unsigned char *ubuf = (unsigned char *)buf; int offset=0; /* put in the header */ RSSVAL(ubuf,offset,nmb->header.name_trn_id); ubuf[offset+2] = (nmb->header.opcode & 0xF) << 3; if (nmb->header.response) ubuf[offset+2] |= (1<<7); if (nmb->header.nm_flags.authoritative && nmb->header.response) ubuf[offset+2] |= 0x4; if (nmb->header.nm_flags.trunc) ubuf[offset+2] |= 0x2; if (nmb->header.nm_flags.recursion_desired) ubuf[offset+2] |= 0x1; if (nmb->header.nm_flags.recursion_available && nmb->header.response) ubuf[offset+3] |= 0x80; if (nmb->header.nm_flags.bcast) ubuf[offset+3] |= 0x10; ubuf[offset+3] |= (nmb->header.rcode & 0xF); RSSVAL(ubuf,offset+4,nmb->header.qdcount); RSSVAL(ubuf,offset+6,nmb->header.ancount); RSSVAL(ubuf,offset+8,nmb->header.nscount); RSSVAL(ubuf,offset+10,nmb->header.arcount); offset += 12; if (nmb->header.qdcount) { /* XXXX this doesn't handle a qdcount of > 1 */ offset += put_nmb_name((char *)ubuf,offset,&nmb->question.question_name); RSSVAL(ubuf,offset,nmb->question.question_type); RSSVAL(ubuf,offset+2,nmb->question.question_class); offset += 4; } if (nmb->header.ancount) offset += put_res_rec((char *)ubuf,offset,nmb->answers, nmb->header.ancount); if (nmb->header.nscount) offset += put_res_rec((char *)ubuf,offset,nmb->nsrecs, nmb->header.nscount); if (nmb->header.arcount) offset += put_res_rec((char *)ubuf,offset,nmb->additional, nmb->header.arcount); return(offset); } /******************************************************************* send a packet_struct ******************************************************************/ BOOL send_packet(struct packet_struct *p) { char buf[1024]; int len=0; bzero(buf,sizeof(buf)); switch (p->packet_type) { case NMB_PACKET: len = build_nmb(buf,p); break; case DGRAM_PACKET: len = build_dgram(buf,p); break; } if (!len) return(False); return(send_udp(p->fd,buf,len,p->ip,p->port)); } /**************************************************************************** receive a packet with timeout on a open UDP filedescriptor The timeout is in milliseconds ***************************************************************************/ struct packet_struct *receive_packet(int fd,enum packet_type type,int t) { fd_set fds; struct timeval timeout; FD_ZERO(&fds); FD_SET(fd,&fds); timeout.tv_sec = t/1000; timeout.tv_usec = 1000*(t%1000); sys_select(&fds,&timeout); if (FD_ISSET(fd,&fds)) return(read_packet(fd,type)); return(NULL); }