src/slirp/udp.c

/*
 * 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"

struct udpstat udpstat;

struct socket udb;

/*
 * UDP protocol implementation.
 * Per RFC 768, August, 1980.
 */
#ifndef COMPAT_42
int     udpcksum = 1;
#else
int     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);
        
        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) {
                        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))) {
            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 {
                  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;
          so->so_faddr = ip->ip_dst; /* XXX */
          so->so_fport = uh->uh_dport; /* XXX */
          
          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.
           */
        }

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

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}
};

u_int8_t
udp_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
 */
void
udp_emu(so, m)
        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        s_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;
                        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
                
        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->s_addr = our_addr.s_addr;
                }
                
                return;
        }
}

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);
        int 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)); */
        
        getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
        so->so_fport = addr.sin_port;
        if (addr.sin_addr.s_addr == 0 || addr.sin_addr.s_addr == loopback_addr.s_addr)
           so->so_faddr = our_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;
}
Revision:	1.3
Committed:	2005-06-30T21:25:26Z (19 years, 4 months ago) by cebix
Content type:	text/plain
Branch:	MAIN
CVS Tags:	nigel-build-17
Changes since 1.2:	+3 -2 lines
Log Message:	minor cleanups
#	User	Rev	Content
1	gbeauche	1.1	/*
2			* Copyright (c) 1982, 1986, 1988, 1990, 1993
3			* The Regents of the University of California. All rights reserved.
4			*
5			* Redistribution and use in source and binary forms, with or without
6			* modification, are permitted provided that the following conditions
7			* are met:
8			* 1. Redistributions of source code must retain the above copyright
9			* notice, this list of conditions and the following disclaimer.
10			* 2. Redistributions in binary form must reproduce the above copyright
11			* notice, this list of conditions and the following disclaimer in the
12			* documentation and/or other materials provided with the distribution.
13			* 3. All advertising materials mentioning features or use of this software
14			* must display the following acknowledgement:
15			* This product includes software developed by the University of
16			* California, Berkeley and its contributors.
17			* 4. Neither the name of the University nor the names of its contributors
18			* may be used to endorse or promote products derived from this software
19			* without specific prior written permission.
20			*
21			* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24			* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31			* SUCH DAMAGE.
32			*
33			* @(#)udp_usrreq.c 8.4 (Berkeley) 1/21/94
34			* udp_usrreq.c,v 1.4 1994/10/02 17:48:45 phk Exp
35			*/
36
37			/*
38			* Changes and additions relating to SLiRP
39			* Copyright (c) 1995 Danny Gasparovski.
40			*
41			* Please read the file COPYRIGHT for the
42			* terms and conditions of the copyright.
43			*/
44
45			#include <slirp.h>
46			#include "ip_icmp.h"
47
48			struct udpstat udpstat;
49
50			struct socket udb;
51
52			/*
53			* UDP protocol implementation.
54			* Per RFC 768, August, 1980.
55			*/
56			#ifndef COMPAT_42
57			int udpcksum = 1;
58			#else
59			int udpcksum = 0; /* XXX */
60			#endif
61
62			struct socket *udp_last_so = &udb;
63
64			void
65			udp_init()
66			{
67			udb.so_next = udb.so_prev = &udb;
68			}
69			/* m->m_data points at ip packet header
70			* m->m_len length ip packet
71			* ip->ip_len length data (IPDU)
72			*/
73			void
74			udp_input(m, iphlen)
75			register struct mbuf *m;
76			int iphlen;
77			{
78			register struct ip *ip;
79			register struct udphdr *uh;
80			/* struct mbuf opts = 0;/
81			int len;
82			struct ip save_ip;
83			struct socket *so;
84
85			DEBUG_CALL("udp_input");
86			DEBUG_ARG("m = %lx", (long)m);
87			DEBUG_ARG("iphlen = %d", iphlen);
88
89			udpstat.udps_ipackets++;
90
91			/*
92			* Strip IP options, if any; should skip this,
93			* make available to user, and use on returned packets,
94			* but we don't yet have a way to check the checksum
95			* with options still present.
96			*/
97			if(iphlen > sizeof(struct ip)) {
98			ip_stripoptions(m, (struct mbuf *)0);
99			iphlen = sizeof(struct ip);
100			}
101
102			/*
103			* Get IP and UDP header together in first mbuf.
104			*/
105			ip = mtod(m, struct ip *);
106			uh = (struct udphdr *)((caddr_t)ip + iphlen);
107
108			/*
109			* Make mbuf data length reflect UDP length.
110			* If not enough data to reflect UDP length, drop.
111			*/
112			len = ntohs((u_int16_t)uh->uh_ulen);
113
114			if (ip->ip_len != len) {
115			if (len > ip->ip_len) {
116			udpstat.udps_badlen++;
117			goto bad;
118			}
119			m_adj(m, len - ip->ip_len);
120			ip->ip_len = len;
121			}
122
123			/*
124			* Save a copy of the IP header in case we want restore it
125			* for sending an ICMP error message in response.
126			*/
127			save_ip = *ip;
128			save_ip.ip_len+= iphlen; /* tcp_input subtracts this */
129
130			/*
131			* Checksum extended UDP header and data.
132			*/
133			if (udpcksum && uh->uh_sum) {
134			((struct ipovly *)ip)->ih_next = 0;
135			((struct ipovly *)ip)->ih_prev = 0;
136			((struct ipovly *)ip)->ih_x1 = 0;
137			((struct ipovly *)ip)->ih_len = uh->uh_ulen;
138			/* keep uh_sum for ICMP reply
139			* uh->uh_sum = cksum(m, len + sizeof (struct ip));
140			* if (uh->uh_sum) {
141			*/
142			if(cksum(m, len + sizeof(struct ip))) {
143			udpstat.udps_badsum++;
144			goto bad;
145			}
146			}
147
148			/*
149			* handle DHCP/BOOTP
150			*/
151			if (ntohs(uh->uh_dport) == BOOTP_SERVER) {
152			bootp_input(m);
153			goto bad;
154			}
155
156			/*
157			* handle TFTP
158			*/
159			if (ntohs(uh->uh_dport) == TFTP_SERVER) {
160			tftp_input(m);
161			goto bad;
162			}
163
164			/*
165			* Locate pcb for datagram.
166			*/
167			so = udp_last_so;
168			if (so->so_lport != uh->uh_sport \|\|
169			so->so_laddr.s_addr != ip->ip_src.s_addr) {
170			struct socket *tmp;
171
172			for (tmp = udb.so_next; tmp != &udb; tmp = tmp->so_next) {
173			if (tmp->so_lport == uh->uh_sport &&
174			tmp->so_laddr.s_addr == ip->ip_src.s_addr) {
175			tmp->so_faddr.s_addr = ip->ip_dst.s_addr;
176			tmp->so_fport = uh->uh_dport;
177			so = tmp;
178			break;
179			}
180			}
181			if (tmp == &udb) {
182			so = NULL;
183			} else {
184			udpstat.udpps_pcbcachemiss++;
185			udp_last_so = so;
186			}
187			}
188
189			if (so == NULL) {
190			/*
191			* If there's no socket for this packet,
192			* create one
193			*/
194			if ((so = socreate()) == NULL) goto bad;
195			if(udp_attach(so) == -1) {
196			DEBUG_MISC((dfd," udp_attach errno = %d-%s\n",
197			errno,strerror(errno)));
198			sofree(so);
199			goto bad;
200			}
201
202			/*
203			* Setup fields
204			*/
205			/* udp_last_so = so; */
206			so->so_laddr = ip->ip_src;
207			so->so_lport = uh->uh_sport;
208			so->so_faddr = ip->ip_dst; /* XXX */
209			so->so_fport = uh->uh_dport; /* XXX */
210
211			if ((so->so_iptos = udp_tos(so)) == 0)
212			so->so_iptos = ip->ip_tos;
213
214			/*
215			* XXXXX Here, check if it's in udpexec_list,
216			* and if it is, do the fork_exec() etc.
217			*/
218			}
219
220			iphlen += sizeof(struct udphdr);
221			m->m_len -= iphlen;
222			m->m_data += iphlen;
223
224			/*
225			* Now we sendto() the packet.
226			*/
227			if (so->so_emu)
228			udp_emu(so, m);
229
230			if(sosendto(so,m) == -1) {
231			m->m_len += iphlen;
232			m->m_data -= iphlen;
233			*ip=save_ip;
234			DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno,strerror(errno)));
235			icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
236			}
237
238			m_free(so->so_m); /* used for ICMP if error on sorecvfrom */
239
240			/* restore the orig mbuf packet */
241			m->m_len += iphlen;
242			m->m_data -= iphlen;
243			*ip=save_ip;
244			so->so_m=m; /* ICMP backup */
245
246			return;
247			bad:
248			m_freem(m);
249			/* if (opts) m_freem(opts); */
250			return;
251			}
252
253			int udp_output2(struct socket so, struct mbuf m,
254			struct sockaddr_in saddr, struct sockaddr_in daddr,
255			int iptos)
256			{
257			register struct udpiphdr *ui;
258			int error = 0;
259
260			DEBUG_CALL("udp_output");
261			DEBUG_ARG("so = %lx", (long)so);
262			DEBUG_ARG("m = %lx", (long)m);
263			DEBUG_ARG("saddr = %lx", (long)saddr->sin_addr.s_addr);
264			DEBUG_ARG("daddr = %lx", (long)daddr->sin_addr.s_addr);
265
266			/*
267			* Adjust for header
268			*/
269			m->m_data -= sizeof(struct udpiphdr);
270			m->m_len += sizeof(struct udpiphdr);
271
272			/*
273			* Fill in mbuf with extended UDP header
274			* and addresses and length put into network format.
275			*/
276			ui = mtod(m, struct udpiphdr *);
277			ui->ui_next = ui->ui_prev = 0;
278			ui->ui_x1 = 0;
279			ui->ui_pr = IPPROTO_UDP;
280			ui->ui_len = htons(m->m_len - sizeof(struct ip)); /* + sizeof (struct udphdr)); */
281			/* XXXXX Check for from-one-location sockets, or from-any-location sockets */
282			ui->ui_src = saddr->sin_addr;
283			ui->ui_dst = daddr->sin_addr;
284			ui->ui_sport = saddr->sin_port;
285			ui->ui_dport = daddr->sin_port;
286			ui->ui_ulen = ui->ui_len;
287
288			/*
289			* Stuff checksum and output datagram.
290			*/
291			ui->ui_sum = 0;
292			if (udpcksum) {
293			if ((ui->ui_sum = cksum(m, /* sizeof (struct udpiphdr) + */ m->m_len)) == 0)
294			ui->ui_sum = 0xffff;
295			}
296			((struct ip *)ui)->ip_len = m->m_len;
297
298			((struct ip *)ui)->ip_ttl = ip_defttl;
299			((struct ip *)ui)->ip_tos = iptos;
300
301			udpstat.udps_opackets++;
302
303			error = ip_output(so, m);
304
305			return (error);
306			}
307
308			int udp_output(struct socket so, struct mbuf m,
309			struct sockaddr_in *addr)
310
311			{
312			struct sockaddr_in saddr, daddr;
313
314			saddr = *addr;
315			if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr)
316			saddr.sin_addr.s_addr = so->so_faddr.s_addr;
317			daddr.sin_addr = so->so_laddr;
318			daddr.sin_port = so->so_lport;
319
320			return udp_output2(so, m, &saddr, &daddr, so->so_iptos);
321			}
322
323			int
324			udp_attach(so)
325			struct socket *so;
326			{
327			struct sockaddr_in addr;
328
329			if((so->s = socket(AF_INET,SOCK_DGRAM,0)) != -1) {
330			/*
331			* Here, we bind() the socket. Although not really needed
332			* (sendto() on an unbound socket will bind it), it's done
333			* here so that emulation of ytalk etc. don't have to do it
334			*/
335			addr.sin_family = AF_INET;
336			addr.sin_port = 0;
337			addr.sin_addr.s_addr = INADDR_ANY;
338			if(bind(so->s, (struct sockaddr *)&addr, sizeof(addr))<0) {
339			int lasterrno=errno;
340			closesocket(so->s);
341			so->s=-1;
342			#ifdef _WIN32
343			WSASetLastError(lasterrno);
344			#else
345			errno=lasterrno;
346			#endif
347			} else {
348			/* success, insert in queue */
349			so->so_expire = curtime + SO_EXPIRE;
350			insque(so,&udb);
351			}
352			}
353			return(so->s);
354			}
355
356			void
357			udp_detach(so)
358			struct socket *so;
359			{
360			closesocket(so->s);
361			/* if (so->so_m) m_free(so->so_m); done by sofree */
362
363			sofree(so);
364			}
365
366			struct tos_t udptos[] = {
367			{0, 53, IPTOS_LOWDELAY, 0}, /* DNS */
368			{517, 517, IPTOS_LOWDELAY, EMU_TALK}, /* talk */
369			{518, 518, IPTOS_LOWDELAY, EMU_NTALK}, /* ntalk */
370			{0, 7648, IPTOS_LOWDELAY, EMU_CUSEEME}, /* Cu-Seeme */
371			{0, 0, 0, 0}
372			};
373
374			u_int8_t
375			udp_tos(so)
376			struct socket *so;
377			{
378			int i = 0;
379
380			while(udptos[i].tos) {
381			if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) \|\|
382			(udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {
383			so->so_emu = udptos[i].emu;
384			return udptos[i].tos;
385			}
386			i++;
387			}
388
389			return 0;
390			}
391
392			#ifdef EMULATE_TALK
393			#include "talkd.h"
394			#endif
395
396			/*
397			* Here, talk/ytalk/ntalk requests must be emulated
398			*/
399			void
400			udp_emu(so, m)
401			struct socket *so;
402			struct mbuf *m;
403			{
404			struct sockaddr_in addr;
405	cebix	1.3	socklen_t addrlen = sizeof(addr);
406	gbeauche	1.1	#ifdef EMULATE_TALK
407			CTL_MSG_OLD *omsg;
408			CTL_MSG *nmsg;
409			char buff[sizeof(CTL_MSG)];
410			u_char type;
411
412			struct talk_request {
413			struct talk_request *next;
414			struct socket *udp_so;
415			struct socket *tcp_so;
416			} *req;
417
418			static struct talk_request *req_tbl = 0;
419
420			#endif
421
422			struct cu_header {
423	gbeauche	1.2	uint16_t d_family; // destination family
424			uint16_t d_port; // destination port
425			uint32_t d_addr; // destination address
426			uint16_t s_family; // source family
427			uint16_t s_port; // source port
428			uint32_t s_addr; // source address
429			uint32_t seqn; // sequence number
430			uint16_t message; // message
431			uint16_t data_type; // data type
432			uint16_t pkt_len; // packet length
433	gbeauche	1.1	} *cu_head;
434
435			switch(so->so_emu) {
436
437			#ifdef EMULATE_TALK
438			case EMU_TALK:
439			case EMU_NTALK:
440			/*
441			* Talk emulation. We always change the ctl_addr to get
442			* some answers from the daemon. When an ANNOUNCE comes,
443			* we send LEAVE_INVITE to the local daemons. Also when a
444			* DELETE comes, we send copies to the local daemons.
445			*/
446			if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0)
447			return;
448
449			#define IS_OLD (so->so_emu == EMU_TALK)
450
451			#define COPY_MSG(dest, src) { dest->type = src->type; \
452			dest->id_num = src->id_num; \
453			dest->pid = src->pid; \
454			dest->addr = src->addr; \
455			dest->ctl_addr = src->ctl_addr; \
456			memcpy(&dest->l_name, &src->l_name, NAME_SIZE_OLD); \
457			memcpy(&dest->r_name, &src->r_name, NAME_SIZE_OLD); \
458			memcpy(&dest->r_tty, &src->r_tty, TTY_SIZE); }
459
460			#define OTOSIN(ptr, field) ((struct sockaddr_in *)&ptr->field)
461			/* old_sockaddr to sockaddr_in */
462
463
464			if (IS_OLD) { /* old talk */
465			omsg = mtod(m, CTL_MSG_OLD*);
466			nmsg = (CTL_MSG *) buff;
467			type = omsg->type;
468			OTOSIN(omsg, ctl_addr)->sin_port = addr.sin_port;
469			OTOSIN(omsg, ctl_addr)->sin_addr = our_addr;
470			strncpy(omsg->l_name, getlogin(), NAME_SIZE_OLD);
471			} else { /* new talk */
472			omsg = (CTL_MSG_OLD *) buff;
473			nmsg = mtod(m, CTL_MSG *);
474			type = nmsg->type;
475			OTOSIN(nmsg, ctl_addr)->sin_port = addr.sin_port;
476			OTOSIN(nmsg, ctl_addr)->sin_addr = our_addr;
477			strncpy(nmsg->l_name, getlogin(), NAME_SIZE_OLD);
478			}
479
480			if (type == LOOK_UP)
481			return; /* for LOOK_UP this is enough */
482
483			if (IS_OLD) { /* make a copy of the message */
484			COPY_MSG(nmsg, omsg);
485			nmsg->vers = 1;
486			nmsg->answer = 0;
487			} else
488			COPY_MSG(omsg, nmsg);
489
490			/*
491			* If if is an ANNOUNCE message, we go through the
492			* request table to see if a tcp port has already
493			* been redirected for this socket. If not, we solisten()
494			* a new socket and add this entry to the table.
495			* The port number of the tcp socket and our IP
496			* are put to the addr field of the message structures.
497			* Then a LEAVE_INVITE is sent to both local daemon
498			* ports, 517 and 518. This is why we have two copies
499			* of the message, one in old talk and one in new talk
500			* format.
501			*/
502
503			if (type == ANNOUNCE) {
504			int s;
505			u_short temp_port;
506
507			for(req = req_tbl; req; req = req->next)
508			if (so == req->udp_so)
509			break; /* found it */
510
511			if (!req) { /* no entry for so, create new */
512			req = (struct talk_request *)
513			malloc(sizeof(struct talk_request));
514			req->udp_so = so;
515			req->tcp_so = solisten(0,
516			OTOSIN(omsg, addr)->sin_addr.s_addr,
517			OTOSIN(omsg, addr)->sin_port,
518			SS_FACCEPTONCE);
519			req->next = req_tbl;
520			req_tbl = req;
521			}
522
523			/* replace port number in addr field */
524			addrlen = sizeof(addr);
525			getsockname(req->tcp_so->s,
526			(struct sockaddr *) &addr,
527			&addrlen);
528			OTOSIN(omsg, addr)->sin_port = addr.sin_port;
529			OTOSIN(omsg, addr)->sin_addr = our_addr;
530			OTOSIN(nmsg, addr)->sin_port = addr.sin_port;
531			OTOSIN(nmsg, addr)->sin_addr = our_addr;
532
533			/* send LEAVE_INVITEs */
534			temp_port = OTOSIN(omsg, ctl_addr)->sin_port;
535			OTOSIN(omsg, ctl_addr)->sin_port = 0;
536			OTOSIN(nmsg, ctl_addr)->sin_port = 0;
537			omsg->type = nmsg->type = LEAVE_INVITE;
538
539			s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
540			addr.sin_addr = our_addr;
541			addr.sin_family = AF_INET;
542			addr.sin_port = htons(517);
543			sendto(s, (char )omsg, sizeof(omsg), 0,
544			(struct sockaddr *)&addr, sizeof(addr));
545			addr.sin_port = htons(518);
546			sendto(s, (char )nmsg, sizeof(nmsg), 0,
547			(struct sockaddr *) &addr, sizeof(addr));
548			closesocket(s) ;
549
550			omsg->type = nmsg->type = ANNOUNCE;
551			OTOSIN(omsg, ctl_addr)->sin_port = temp_port;
552			OTOSIN(nmsg, ctl_addr)->sin_port = temp_port;
553			}
554
555			/*
556			* If it is a DELETE message, we send a copy to the
557			* local daemons. Then we delete the entry corresponding
558			* to our socket from the request table.
559			*/
560
561			if (type == DELETE) {
562			struct talk_request temp_req, req_next;
563			int s;
564			u_short temp_port;
565
566			temp_port = OTOSIN(omsg, ctl_addr)->sin_port;
567			OTOSIN(omsg, ctl_addr)->sin_port = 0;
568			OTOSIN(nmsg, ctl_addr)->sin_port = 0;
569
570			s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
571			addr.sin_addr = our_addr;
572			addr.sin_family = AF_INET;
573			addr.sin_port = htons(517);
574			sendto(s, (char )omsg, sizeof(omsg), 0,
575			(struct sockaddr *)&addr, sizeof(addr));
576			addr.sin_port = htons(518);
577			sendto(s, (char )nmsg, sizeof(nmsg), 0,
578			(struct sockaddr *)&addr, sizeof(addr));
579			closesocket(s);
580
581			OTOSIN(omsg, ctl_addr)->sin_port = temp_port;
582			OTOSIN(nmsg, ctl_addr)->sin_port = temp_port;
583
584			/* delete table entry */
585			if (so == req_tbl->udp_so) {
586			temp_req = req_tbl;
587			req_tbl = req_tbl->next;
588			free(temp_req);
589			} else {
590			temp_req = req_tbl;
591			for(req = req_tbl->next; req; req = req_next) {
592			req_next = req->next;
593			if (so == req->udp_so) {
594			temp_req->next = req_next;
595			free(req);
596			break;
597			} else {
598			temp_req = req;
599			}
600			}
601			}
602			}
603
604			return;
605			#endif
606
607			case EMU_CUSEEME:
608
609			/*
610			* Cu-SeeMe emulation.
611			* Hopefully the packet is more that 16 bytes long. We don't
612			* do any other tests, just replace the address and port
613			* fields.
614			*/
615			if (m->m_len >= sizeof (*cu_head)) {
616			if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0)
617			return;
618			cu_head = mtod(m, struct cu_header *);
619	gbeauche	1.2	cu_head->s_port = addr.sin_port;
620			cu_head->s_addr = our_addr.s_addr;
621	gbeauche	1.1	}
622
623			return;
624			}
625			}
626
627			struct socket *
628			udp_listen(port, laddr, lport, flags)
629			u_int port;
630			u_int32_t laddr;
631			u_int lport;
632			int flags;
633			{
634			struct sockaddr_in addr;
635			struct socket *so;
636	cebix	1.3	socklen_t addrlen = sizeof(struct sockaddr_in);
637			int opt = 1;
638	gbeauche	1.1
639			if ((so = socreate()) == NULL) {
640			free(so);
641			return NULL;
642			}
643			so->s = socket(AF_INET,SOCK_DGRAM,0);
644			so->so_expire = curtime + SO_EXPIRE;
645			insque(so,&udb);
646
647			addr.sin_family = AF_INET;
648			addr.sin_addr.s_addr = INADDR_ANY;
649			addr.sin_port = port;
650
651			if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) {
652			udp_detach(so);
653			return NULL;
654			}
655			setsockopt(so->s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int));
656			/* setsockopt(so->s,SOL_SOCKET,SO_OOBINLINE,(char )&opt,sizeof(int)); /
657
658			getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
659			so->so_fport = addr.sin_port;
660			if (addr.sin_addr.s_addr == 0 \|\| addr.sin_addr.s_addr == loopback_addr.s_addr)
661			so->so_faddr = our_addr;
662			else
663			so->so_faddr = addr.sin_addr;
664
665			so->so_lport = lport;
666			so->so_laddr.s_addr = laddr;
667			if (flags != SS_FACCEPTONCE)
668			so->so_expire = 0;
669
670			so->so_state = SS_ISFCONNECTED;
671
672			return so;
673			}