/*

 * Copyright (c) 1982, 1986, 1988, 1990, 1993

 *	The Regents of the University of California.  All rights reserved.

 *

 * 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. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *	This product includes software developed by the University of

 *	California, Berkeley and its contributors.

 * 4. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.

 *

 *	@(#)udp_usrreq.c	8.4 (Berkeley) 1/21/94

 * udp_usrreq.c,v 1.4 1994/10/02 17:48:45 phk Exp

 */

/*

 * Changes and additions relating to SLiRP

 * Copyright (c) 1995 Danny Gasparovski.

 *

 * Please read the file COPYRIGHT for the

 * terms and conditions of the copyright.

 */

#include <slirp.h>

#include "ip_icmp.h"

#ifdef LOG_ENABLED

struct udpstat udpstat;

#endif

struct socket udb;

static u_int8_t udp_tos(struct socket *so);

static void udp_emu(struct socket *so, struct mbuf *m);

/*

 * UDP protocol implementation.

 * Per RFC 768, August, 1980.

 */

#ifndef	COMPAT_42

#define UDPCKSUM 1

#else

#define UDPCKSUM 0 /* XXX */

#endif

struct	socket *udp_last_so = &udb;

void

udp_init()

{

	udb.so_next = udb.so_prev = &udb;

}

/* m->m_data  points at ip packet header

 * m->m_len   length ip packet

 * ip->ip_len length data (IPDU)

 */

void

udp_input(m, iphlen)

	register struct mbuf *m;

	int iphlen;

{

	register struct ip *ip;

	register struct udphdr *uh;

/*	struct mbuf *opts = 0;*/

	int len;

	struct ip save_ip;

	struct socket *so;

	DEBUG_CALL("udp_input");

	DEBUG_ARG("m = %lx", (long)m);

	DEBUG_ARG("iphlen = %d", iphlen);

	STAT(udpstat.udps_ipackets++);

	/*

	 * Strip IP options, if any; should skip this,

	 * make available to user, and use on returned packets,

	 * but we don't yet have a way to check the checksum

	 * with options still present.

	 */

	if(iphlen > sizeof(struct ip)) {

		ip_stripoptions(m, (struct mbuf *)0);

		iphlen = sizeof(struct ip);

	}

	/*

	 * Get IP and UDP header together in first mbuf.

	 */

	ip = mtod(m, struct ip *);

	uh = (struct udphdr *)((caddr_t)ip + iphlen);

	/*

	 * Make mbuf data length reflect UDP length.

	 * If not enough data to reflect UDP length, drop.

	 */

	len = ntohs((u_int16_t)uh->uh_ulen);

	if (ip->ip_len != len) {

		if (len > ip->ip_len) {

			STAT(udpstat.udps_badlen++);

			goto bad;

		}

		m_adj(m, len - ip->ip_len);

		ip->ip_len = len;

	}

	/*

	 * Save a copy of the IP header in case we want restore it

	 * for sending an ICMP error message in response.

	 */

	save_ip = *ip;

	save_ip.ip_len+= iphlen;         /* tcp_input subtracts this */

	/*

	 * Checksum extended UDP header and data.

	 */

	if (UDPCKSUM && uh->uh_sum) {

	  ((struct ipovly *)ip)->ih_next = 0;

	  ((struct ipovly *)ip)->ih_prev = 0;

	  ((struct ipovly *)ip)->ih_x1 = 0;

	  ((struct ipovly *)ip)->ih_len = uh->uh_ulen;

	  /* keep uh_sum for ICMP reply

	   * uh->uh_sum = cksum(m, len + sizeof (struct ip));

	   * if (uh->uh_sum) {

	   */

	  if(cksum(m, len + sizeof(struct ip))) {

	    STAT(udpstat.udps_badsum++);

	    goto bad;

	  }

	}

        /*

         *  handle DHCP/BOOTP

         */

        if (ntohs(uh->uh_dport) == BOOTP_SERVER) {

            bootp_input(m);

            goto bad;

        }

        /*

         *  handle TFTP

         */

        if (ntohs(uh->uh_dport) == TFTP_SERVER) {

            tftp_input(m);

            goto bad;

        }

	/*

	 * Locate pcb for datagram.

	 */

	so = udp_last_so;

	if (so->so_lport != uh->uh_sport ||

	    so->so_laddr.s_addr != ip->ip_src.s_addr) {

		struct socket *tmp;

		for (tmp = udb.so_next; tmp != &udb; tmp = tmp->so_next) {

			if (tmp->so_lport == uh->uh_sport &&

			    tmp->so_laddr.s_addr == ip->ip_src.s_addr) {

				tmp->so_faddr.s_addr = ip->ip_dst.s_addr;

				tmp->so_fport = uh->uh_dport;

				so = tmp;

				break;

			}

		}

		if (tmp == &udb) {

		  so = NULL;

		} else {

		  STAT(udpstat.udpps_pcbcachemiss++);

		  udp_last_so = so;

		}

	}

	if (so == NULL) {

	  /*

	   * If there's no socket for this packet,

	   * create one

	   */

	  if ((so = socreate()) == NULL) goto bad;

	  if(udp_attach(so) == -1) {

	    DEBUG_MISC((dfd," udp_attach errno = %d-%s\n",

			errno,strerror(errno)));

	    sofree(so);

	    goto bad;

	  }

	  /*

	   * Setup fields

	   */

	  /* udp_last_so = so; */

	  so->so_laddr = ip->ip_src;

	  so->so_lport = uh->uh_sport;

	  if ((so->so_iptos = udp_tos(so)) == 0)

	    so->so_iptos = ip->ip_tos;

	  /*

	   * XXXXX Here, check if it's in udpexec_list,

	   * and if it is, do the fork_exec() etc.

	   */

	}

        so->so_faddr = ip->ip_dst; /* XXX */

        so->so_fport = uh->uh_dport; /* XXX */

	iphlen += sizeof(struct udphdr);

	m->m_len -= iphlen;

	m->m_data += iphlen;

	/*

	 * Now we sendto() the packet.

	 */

	if (so->so_emu)

	   udp_emu(so, m);

	if(sosendto(so,m) == -1) {

	  m->m_len += iphlen;

	  m->m_data -= iphlen;

	  *ip=save_ip;

	  DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno,strerror(errno)));

	  icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));

	}

	m_free(so->so_m);   /* used for ICMP if error on sorecvfrom */

	/* restore the orig mbuf packet */

	m->m_len += iphlen;

	m->m_data -= iphlen;

	*ip=save_ip;

	so->so_m=m;         /* ICMP backup */

	return;

bad:

	m_freem(m);

	/* if (opts) m_freem(opts); */

	return;

}

int udp_output2(struct socket *so, struct mbuf *m,

                struct sockaddr_in *saddr, struct sockaddr_in *daddr,

                int iptos)

{

	register struct udpiphdr *ui;

	int error = 0;

	DEBUG_CALL("udp_output");

	DEBUG_ARG("so = %lx", (long)so);

	DEBUG_ARG("m = %lx", (long)m);

	DEBUG_ARG("saddr = %lx", (long)saddr->sin_addr.s_addr);

	DEBUG_ARG("daddr = %lx", (long)daddr->sin_addr.s_addr);

	/*

	 * Adjust for header

	 */

	m->m_data -= sizeof(struct udpiphdr);

	m->m_len += sizeof(struct udpiphdr);

	/*

	 * Fill in mbuf with extended UDP header

	 * and addresses and length put into network format.

	 */

	ui = mtod(m, struct udpiphdr *);

	ui->ui_next = ui->ui_prev = 0;

	ui->ui_x1 = 0;

	ui->ui_pr = IPPROTO_UDP;

	ui->ui_len = htons(m->m_len - sizeof(struct ip)); /* + sizeof (struct udphdr)); */

	/* XXXXX Check for from-one-location sockets, or from-any-location sockets */

        ui->ui_src = saddr->sin_addr;

	ui->ui_dst = daddr->sin_addr;

	ui->ui_sport = saddr->sin_port;

	ui->ui_dport = daddr->sin_port;

	ui->ui_ulen = ui->ui_len;

	/*

	 * Stuff checksum and output datagram.

	 */

	ui->ui_sum = 0;

	if (UDPCKSUM) {

	    if ((ui->ui_sum = cksum(m, /* sizeof (struct udpiphdr) + */ m->m_len)) == 0)

		ui->ui_sum = 0xffff;

	}

	((struct ip *)ui)->ip_len = m->m_len;

	((struct ip *)ui)->ip_ttl = IPDEFTTL;

	((struct ip *)ui)->ip_tos = iptos;

	STAT(udpstat.udps_opackets++);

	error = ip_output(so, m);

	return (error);

}

int udp_output(struct socket *so, struct mbuf *m,

               struct sockaddr_in *addr)

{

    struct sockaddr_in saddr, daddr;

    saddr = *addr;

    if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr) {

        if ((so->so_faddr.s_addr & htonl(0x000000ff)) == htonl(0xff))

            saddr.sin_addr.s_addr = alias_addr.s_addr;

        else if (addr->sin_addr.s_addr == loopback_addr.s_addr ||

                 (ntohl(so->so_faddr.s_addr) & 0xff) != CTL_ALIAS)

            saddr.sin_addr.s_addr = so->so_faddr.s_addr;

    }

    daddr.sin_addr = so->so_laddr;

    daddr.sin_port = so->so_lport;

    return udp_output2(so, m, &saddr, &daddr, so->so_iptos);

}

int

udp_attach(so)

     struct socket *so;

{

  struct sockaddr_in addr;

  if((so->s = socket(AF_INET,SOCK_DGRAM,0)) != -1) {

    /*

     * Here, we bind() the socket.  Although not really needed

     * (sendto() on an unbound socket will bind it), it's done

     * here so that emulation of ytalk etc. don't have to do it

     */

    addr.sin_family = AF_INET;

    addr.sin_port = 0;

    addr.sin_addr.s_addr = INADDR_ANY;

    if(bind(so->s, (struct sockaddr *)&addr, sizeof(addr))<0) {

      int lasterrno=errno;

      closesocket(so->s);

      so->s=-1;

#ifdef _WIN32

      WSASetLastError(lasterrno);

#else

      errno=lasterrno;

#endif

    } else {

      /* success, insert in queue */

      so->so_expire = curtime + SO_EXPIRE;

      insque(so,&udb);

    }

  }

  return(so->s);

}

void

udp_detach(so)

	struct socket *so;

{

	closesocket(so->s);

	/* if (so->so_m) m_free(so->so_m);    done by sofree */

	sofree(so);

}

static const struct tos_t udptos[] = {

	{0, 53, IPTOS_LOWDELAY, 0},			/* DNS */

	{517, 517, IPTOS_LOWDELAY, EMU_TALK},	/* talk */

	{518, 518, IPTOS_LOWDELAY, EMU_NTALK},	/* ntalk */

	{0, 7648, IPTOS_LOWDELAY, EMU_CUSEEME},	/* Cu-Seeme */

	{0, 0, 0, 0}

};

static u_int8_t

udp_tos(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

 */

static void

udp_emu(struct socket *so, struct mbuf *m)

{

	struct sockaddr_in addr;

	socklen_t addrlen = sizeof(addr);

#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

struct 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;

	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;

                        pstrcpy(omsg->l_name, NAME_SIZE_OLD, getlogin());

		} 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;

                        pstrcpy(nmsg->l_name, NAME_SIZE_OLD, getlogin());

		}

		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;