int lasterrno=errno;      closesocket(so->s);      so->s=-1;#ifdef _WIN32      WSASetLastError(lasterrno);#else      errno=lasterrno;#endif    } else {      /* success, insert in queue */      setsockopt(so->s,SOL_SOCKET,SO_RCVBUF,(char *)&max_rcvbuf_size,sizeof(int));      so->so_expire = curtime + SO_EXPIRE;      insque(so,&udb);    }  }  return(so->s);}voidudp_detach(so)	struct socket *so;{	closesocket(so->s);	/* if (so->so_m) m_free(so->so_m);    done by sofree */	sofree(so);}struct tos_t udptos[] = {	{0, 53, IPTOS_LOWDELAY, 0},			/* DNS */#ifdef EMULATE_TALK	{517, 517, IPTOS_LOWDELAY, EMU_TALK},	/* talk */	{518, 518, IPTOS_LOWDELAY, EMU_NTALK},	/* ntalk */#endif#ifdef EMULATE_CUSEEME	{0, 7648, IPTOS_LOWDELAY, EMU_CUSEEME},	/* Cu-Seeme */#endif	{0, 0, 0, 0}};u_int8_tudp_tos(so)	struct socket *so;{	int i = 0;		while(udptos[i].tos) {		if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) ||		    (udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {		    	so->so_emu = udptos[i].emu;			return udptos[i].tos;		}		i++;	}		return 0;}#ifdef EMULATE_TALK#include "talkd.h"#endif/* * Here, talk/ytalk/ntalk requests must be emulated */voidudp_emu(so, m)	struct socket *so;	struct mbuf *m;{#if defined(EMULATE_TALK) || defined(EMULATE_CUSEEME)	struct sockaddr_in addr;        int addrlen = sizeof(addr);#endif#ifdef EMULATE_TALK	CTL_MSG_OLD *omsg;	CTL_MSG *nmsg;	char buff[sizeof(CTL_MSG)];	u_char type;	struct talk_request {	struct talk_request *next;	struct socket *udp_so;	struct socket *tcp_so;} *req;		static struct talk_request *req_tbl = 0;	#endif#ifdef EMULATE_TALKstruct cu_header {	uint16_t	d_family;		// destination family	uint16_t	d_port;			// destination port	uint32_t	d_addr;			// destination address	uint16_t	s_family;		// source family	uint16_t	s_port;			// source port	uint32_t	so_addr;		// source address	uint32_t	seqn;			// sequence number	uint16_t	message;		// message	uint16_t	data_type;		// data type	uint16_t	pkt_len;		// packet length} *cu_head;#endif	switch(so->so_emu) {#ifdef EMULATE_TALK	 case EMU_TALK:	 case EMU_NTALK:		/*		 * Talk emulation. We always change the ctl_addr to get		 * some answers from the daemon. When an ANNOUNCE comes,		 * we send LEAVE_INVITE to the local daemons. Also when a		 * DELETE comes, we send copies to the local daemons.		 */		if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0)			return;		#define	IS_OLD	(so->so_emu == EMU_TALK)#define COPY_MSG(dest, src) { dest->type = src->type; \			      dest->id_num = src->id_num; \			      dest->pid = src->pid; \			      dest->addr = src->addr; \			      dest->ctl_addr = src->ctl_addr; \			      memcpy(&dest->l_name, &src->l_name, NAME_SIZE_OLD); \			      memcpy(&dest->r_name, &src->r_name, NAME_SIZE_OLD); \	         	      memcpy(&dest->r_tty, &src->r_tty, TTY_SIZE); }#define OTOSIN(ptr, field) ((struct sockaddr_in *)&ptr->field)/* old_sockaddr to sockaddr_in */		if (IS_OLD) {  		/* old talk */			omsg = mtod(m, CTL_MSG_OLD*);			nmsg = (CTL_MSG *) buff;			type = omsg->type;			OTOSIN(omsg, ctl_addr)->sin_port = addr.sin_port;			OTOSIN(omsg, ctl_addr)->sin_addr = our_addr;			strncpy(omsg->l_name, getlogin(), NAME_SIZE_OLD);		} else {		/* new talk */				omsg = (CTL_MSG_OLD *) buff;			nmsg = mtod(m, CTL_MSG *);			type = nmsg->type;			OTOSIN(nmsg, ctl_addr)->sin_port = addr.sin_port;			OTOSIN(nmsg, ctl_addr)->sin_addr = our_addr;			strncpy(nmsg->l_name, getlogin(), NAME_SIZE_OLD);		}				if (type == LOOK_UP) 			return;		/* for LOOK_UP this is enough */					if (IS_OLD) {		/* make a copy of the message */			COPY_MSG(nmsg, omsg);			nmsg->vers = 1;			nmsg->answer = 0;		} else			COPY_MSG(omsg, nmsg);		/*		 * If if is an ANNOUNCE message, we go through the		 * request table to see if a tcp port has already		 * been redirected for this socket. If not, we solisten()		 * a new socket and add this entry to the table.		 * The port number of the tcp socket and our IP		 * are put to the addr field of the message structures.		 * Then a LEAVE_INVITE is sent to both local daemon		 * ports, 517 and 518. This is why we have two copies		 * of the message, one in old talk and one in new talk		 * format.		 */ 		if (type == ANNOUNCE) {			int s;			u_short temp_port;						for(req = req_tbl; req; req = req->next)				if (so == req->udp_so)					break;  	/* found it */								if (!req) {	/* no entry for so, create new */				req = (struct talk_request *)					malloc(sizeof(struct talk_request));				req->udp_so = so;				req->tcp_so = solisten(0,							OTOSIN(omsg, addr)->sin_addr.s_addr,						OTOSIN(omsg, addr)->sin_port,					SS_FACCEPTONCE);				req->next = req_tbl;				req_tbl = req;			}									/* replace port number in addr field */			addrlen = sizeof(addr);			getsockname(req->tcp_so->s, 					(struct sockaddr *) &addr,					&addrlen);					OTOSIN(omsg, addr)->sin_port = addr.sin_port;			OTOSIN(omsg, addr)->sin_addr = our_addr;			OTOSIN(nmsg, addr)->sin_port = addr.sin_port;			OTOSIN(nmsg, addr)->sin_addr = our_addr;						/* send LEAVE_INVITEs */			temp_port = OTOSIN(omsg, ctl_addr)->sin_port;			OTOSIN(omsg, ctl_addr)->sin_port = 0;			OTOSIN(nmsg, ctl_addr)->sin_port = 0;			omsg->type = nmsg->type = LEAVE_INVITE;									s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);			addr.sin_addr = our_addr;			addr.sin_family = AF_INET;			addr.sin_port = htons(517);			sendto(s, (char *)omsg, sizeof(*omsg), 0, 				(struct sockaddr *)&addr, sizeof(addr));			addr.sin_port = htons(518);			sendto(s, (char *)nmsg, sizeof(*nmsg), 0,				(struct sockaddr *) &addr, sizeof(addr));			closesocket(s) ;			omsg->type = nmsg->type = ANNOUNCE; 			OTOSIN(omsg, ctl_addr)->sin_port = temp_port;			OTOSIN(nmsg, ctl_addr)->sin_port = temp_port;		}				/*			 * If it is a DELETE message, we send a copy to the		 * local daemons. Then we delete the entry corresponding		 * to our socket from the request table.		 */				if (type == DELETE) {			struct talk_request *temp_req, *req_next;			int s;			u_short temp_port;						temp_port = OTOSIN(omsg, ctl_addr)->sin_port;			OTOSIN(omsg, ctl_addr)->sin_port = 0;			OTOSIN(nmsg, ctl_addr)->sin_port = 0;						s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);			addr.sin_addr = our_addr;			addr.sin_family = AF_INET;			addr.sin_port = htons(517);			sendto(s, (char *)omsg, sizeof(*omsg), 0,				(struct sockaddr *)&addr, sizeof(addr));			addr.sin_port = htons(518);			sendto(s, (char *)nmsg, sizeof(*nmsg), 0,				(struct sockaddr *)&addr, sizeof(addr));			closesocket(s);						OTOSIN(omsg, ctl_addr)->sin_port = temp_port;			OTOSIN(nmsg, ctl_addr)->sin_port = temp_port;			/* delete table entry */			if (so == req_tbl->udp_so) {				temp_req = req_tbl;				req_tbl = req_tbl->next;				free(temp_req);			} else {				temp_req = req_tbl;				for(req = req_tbl->next; req; req = req_next) {					req_next = req->next;					if (so == req->udp_so) {						temp_req->next = req_next;						free(req);						break;					} else {						temp_req = req;					}				}			}		}				return;		#endif		#ifdef EMULATE_CUSEEME	case EMU_CUSEEME:			/*		 * Cu-SeeMe emulation.		 * Hopefully the packet is more that 16 bytes long. We don't		 * do any other tests, just replace the address and port		 * fields.		 */ 		if (m->m_len >= sizeof (*cu_head)) {			if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0)				return;			cu_head = mtod(m, struct cu_header *);			cu_head->s_port = addr.sin_port;			cu_head->so_addr = our_addr.s_addr;		}				return;#endif	}}struct socket *udp_listen(port, laddr, lport, flags)	u_int port;	u_int32_t laddr;	u_int lport;	int flags;{	struct sockaddr_in addr;	struct socket *so;	socklen_t addrlen = sizeof(struct sockaddr_in), opt = 1;		if ((so = socreate()) == NULL) {		free(so);		return NULL;	}	so->s = socket(AF_INET,SOCK_DGRAM,0);	so->so_expire = curtime + SO_EXPIRE;	insque(so,&udb);	addr.sin_family = AF_INET;	addr.sin_addr.s_addr = INADDR_ANY;	addr.sin_port = port;	if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) {		udp_detach(so);		return NULL;	}	setsockopt(so->s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int));/*	setsockopt(so->s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(int)); */	setsockopt(so->s,SOL_SOCKET,SO_RCVBUF,(char *)&max_rcvbuf_size,sizeof(int));		getsockname(so->s,(struct sockaddr *)&addr,&addrlen);	so->so_fport = addr.sin_port;	/* Translate connections from localhost to the alias hostname */	if (is_localhost(addr.sin_addr))	   so->so_faddr = alias_addr;	else	   so->so_faddr = addr.sin_addr;		so->so_lport = lport;	so->so_laddr.s_addr = laddr;	if (flags != SS_FACCEPTONCE)	   so->so_expire = 0;		so->so_state = SS_ISFCONNECTED;		return so;}