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;
          
          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 = 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;
        if ((so->so_faddr.s_addr & htonl(0x000000ff)) == htonl(0xff))
            saddr.sin_addr.s_addr = alias_addr.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        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;
                        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->so_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 = 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;
}
Revision:	1.6
Committed:	2007-11-03T16:36:35Z (16 years, 11 months ago) by gbeauche
Content type:	text/plain
Branch:	MAIN
Changes since 1.5:	+3 -2 lines
Log Message:	Update to slirp sources from QEMU 0.9.0: - fix UDP (Jason Wessel) - enable TCP_NODELAY for slirp redirection (Daniel Jacobowitz)
#	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
209			if ((so->so_iptos = udp_tos(so)) == 0)
210			so->so_iptos = ip->ip_tos;
211
212			/*
213			* XXXXX Here, check if it's in udpexec_list,
214			* and if it is, do the fork_exec() etc.
215			*/
216			}
217
218	gbeauche	1.6	so->so_faddr = ip->ip_dst; /* XXX */
219			so->so_fport = uh->uh_dport; /* XXX */
220
221	gbeauche	1.1	iphlen += sizeof(struct udphdr);
222			m->m_len -= iphlen;
223			m->m_data += iphlen;
224
225			/*
226			* Now we sendto() the packet.
227			*/
228			if (so->so_emu)
229			udp_emu(so, m);
230
231			if(sosendto(so,m) == -1) {
232			m->m_len += iphlen;
233			m->m_data -= iphlen;
234			*ip=save_ip;
235			DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno,strerror(errno)));
236			icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
237			}
238
239			m_free(so->so_m); /* used for ICMP if error on sorecvfrom */
240
241			/* restore the orig mbuf packet */
242			m->m_len += iphlen;
243			m->m_data -= iphlen;
244			*ip=save_ip;
245			so->so_m=m; /* ICMP backup */
246
247			return;
248			bad:
249			m_freem(m);
250			/* if (opts) m_freem(opts); */
251			return;
252			}
253
254			int udp_output2(struct socket so, struct mbuf m,
255			struct sockaddr_in saddr, struct sockaddr_in daddr,
256			int iptos)
257			{
258			register struct udpiphdr *ui;
259			int error = 0;
260
261			DEBUG_CALL("udp_output");
262			DEBUG_ARG("so = %lx", (long)so);
263			DEBUG_ARG("m = %lx", (long)m);
264			DEBUG_ARG("saddr = %lx", (long)saddr->sin_addr.s_addr);
265			DEBUG_ARG("daddr = %lx", (long)daddr->sin_addr.s_addr);
266
267			/*
268			* Adjust for header
269			*/
270			m->m_data -= sizeof(struct udpiphdr);
271			m->m_len += sizeof(struct udpiphdr);
272
273			/*
274			* Fill in mbuf with extended UDP header
275			* and addresses and length put into network format.
276			*/
277			ui = mtod(m, struct udpiphdr *);
278			ui->ui_next = ui->ui_prev = 0;
279			ui->ui_x1 = 0;
280			ui->ui_pr = IPPROTO_UDP;
281			ui->ui_len = htons(m->m_len - sizeof(struct ip)); /* + sizeof (struct udphdr)); */
282			/* XXXXX Check for from-one-location sockets, or from-any-location sockets */
283			ui->ui_src = saddr->sin_addr;
284			ui->ui_dst = daddr->sin_addr;
285			ui->ui_sport = saddr->sin_port;
286			ui->ui_dport = daddr->sin_port;
287			ui->ui_ulen = ui->ui_len;
288
289			/*
290			* Stuff checksum and output datagram.
291			*/
292			ui->ui_sum = 0;
293			if (udpcksum) {
294			if ((ui->ui_sum = cksum(m, /* sizeof (struct udpiphdr) + */ m->m_len)) == 0)
295			ui->ui_sum = 0xffff;
296			}
297			((struct ip *)ui)->ip_len = m->m_len;
298
299			((struct ip *)ui)->ip_ttl = ip_defttl;
300			((struct ip *)ui)->ip_tos = iptos;
301
302			udpstat.udps_opackets++;
303
304			error = ip_output(so, m);
305
306			return (error);
307			}
308
309			int udp_output(struct socket so, struct mbuf m,
310			struct sockaddr_in *addr)
311
312			{
313			struct sockaddr_in saddr, daddr;
314
315			saddr = *addr;
316	gbeauche	1.5	if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr) {
317	gbeauche	1.1	saddr.sin_addr.s_addr = so->so_faddr.s_addr;
318	gbeauche	1.5	if ((so->so_faddr.s_addr & htonl(0x000000ff)) == htonl(0xff))
319			saddr.sin_addr.s_addr = alias_addr.s_addr;
320			}
321	gbeauche	1.1	daddr.sin_addr = so->so_laddr;
322			daddr.sin_port = so->so_lport;
323
324			return udp_output2(so, m, &saddr, &daddr, so->so_iptos);
325			}
326
327			int
328			udp_attach(so)
329			struct socket *so;
330			{
331			struct sockaddr_in addr;
332
333			if((so->s = socket(AF_INET,SOCK_DGRAM,0)) != -1) {
334			/*
335			* Here, we bind() the socket. Although not really needed
336			* (sendto() on an unbound socket will bind it), it's done
337			* here so that emulation of ytalk etc. don't have to do it
338			*/
339			addr.sin_family = AF_INET;
340			addr.sin_port = 0;
341			addr.sin_addr.s_addr = INADDR_ANY;
342			if(bind(so->s, (struct sockaddr *)&addr, sizeof(addr))<0) {
343			int lasterrno=errno;
344			closesocket(so->s);
345			so->s=-1;
346			#ifdef _WIN32
347			WSASetLastError(lasterrno);
348			#else
349			errno=lasterrno;
350			#endif
351			} else {
352			/* success, insert in queue */
353			so->so_expire = curtime + SO_EXPIRE;
354			insque(so,&udb);
355			}
356			}
357			return(so->s);
358			}
359
360			void
361			udp_detach(so)
362			struct socket *so;
363			{
364			closesocket(so->s);
365			/* if (so->so_m) m_free(so->so_m); done by sofree */
366
367			sofree(so);
368			}
369
370			struct tos_t udptos[] = {
371			{0, 53, IPTOS_LOWDELAY, 0}, /* DNS */
372			{517, 517, IPTOS_LOWDELAY, EMU_TALK}, /* talk */
373			{518, 518, IPTOS_LOWDELAY, EMU_NTALK}, /* ntalk */
374			{0, 7648, IPTOS_LOWDELAY, EMU_CUSEEME}, /* Cu-Seeme */
375			{0, 0, 0, 0}
376			};
377
378			u_int8_t
379			udp_tos(so)
380			struct socket *so;
381			{
382			int i = 0;
383
384			while(udptos[i].tos) {
385			if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) \|\|
386			(udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {
387			so->so_emu = udptos[i].emu;
388			return udptos[i].tos;
389			}
390			i++;
391			}
392
393			return 0;
394			}
395
396			#ifdef EMULATE_TALK
397			#include "talkd.h"
398			#endif
399
400			/*
401			* Here, talk/ytalk/ntalk requests must be emulated
402			*/
403			void
404			udp_emu(so, m)
405			struct socket *so;
406			struct mbuf *m;
407			{
408			struct sockaddr_in addr;
409	cebix	1.3	socklen_t addrlen = sizeof(addr);
410	gbeauche	1.1	#ifdef EMULATE_TALK
411			CTL_MSG_OLD *omsg;
412			CTL_MSG *nmsg;
413			char buff[sizeof(CTL_MSG)];
414			u_char type;
415
416			struct talk_request {
417			struct talk_request *next;
418			struct socket *udp_so;
419			struct socket *tcp_so;
420			} *req;
421
422			static struct talk_request *req_tbl = 0;
423
424			#endif
425
426			struct cu_header {
427	gbeauche	1.2	uint16_t d_family; // destination family
428			uint16_t d_port; // destination port
429			uint32_t d_addr; // destination address
430			uint16_t s_family; // source family
431			uint16_t s_port; // source port
432	gbeauche	1.4	uint32_t so_addr; // source address
433	gbeauche	1.2	uint32_t seqn; // sequence number
434			uint16_t message; // message
435			uint16_t data_type; // data type
436			uint16_t pkt_len; // packet length
437	gbeauche	1.1	} *cu_head;
438
439			switch(so->so_emu) {
440
441			#ifdef EMULATE_TALK
442			case EMU_TALK:
443			case EMU_NTALK:
444			/*
445			* Talk emulation. We always change the ctl_addr to get
446			* some answers from the daemon. When an ANNOUNCE comes,
447			* we send LEAVE_INVITE to the local daemons. Also when a
448			* DELETE comes, we send copies to the local daemons.
449			*/
450			if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0)
451			return;
452
453			#define IS_OLD (so->so_emu == EMU_TALK)
454
455			#define COPY_MSG(dest, src) { dest->type = src->type; \
456			dest->id_num = src->id_num; \
457			dest->pid = src->pid; \
458			dest->addr = src->addr; \
459			dest->ctl_addr = src->ctl_addr; \
460			memcpy(&dest->l_name, &src->l_name, NAME_SIZE_OLD); \
461			memcpy(&dest->r_name, &src->r_name, NAME_SIZE_OLD); \
462			memcpy(&dest->r_tty, &src->r_tty, TTY_SIZE); }
463
464			#define OTOSIN(ptr, field) ((struct sockaddr_in *)&ptr->field)
465			/* old_sockaddr to sockaddr_in */
466
467
468			if (IS_OLD) { /* old talk */
469			omsg = mtod(m, CTL_MSG_OLD*);
470			nmsg = (CTL_MSG *) buff;
471			type = omsg->type;
472			OTOSIN(omsg, ctl_addr)->sin_port = addr.sin_port;
473			OTOSIN(omsg, ctl_addr)->sin_addr = our_addr;
474			strncpy(omsg->l_name, getlogin(), NAME_SIZE_OLD);
475			} else { /* new talk */
476			omsg = (CTL_MSG_OLD *) buff;
477			nmsg = mtod(m, CTL_MSG *);
478			type = nmsg->type;
479			OTOSIN(nmsg, ctl_addr)->sin_port = addr.sin_port;
480			OTOSIN(nmsg, ctl_addr)->sin_addr = our_addr;
481			strncpy(nmsg->l_name, getlogin(), NAME_SIZE_OLD);
482			}
483
484			if (type == LOOK_UP)
485			return; /* for LOOK_UP this is enough */
486
487			if (IS_OLD) { /* make a copy of the message */
488			COPY_MSG(nmsg, omsg);
489			nmsg->vers = 1;
490			nmsg->answer = 0;
491			} else
492			COPY_MSG(omsg, nmsg);
493
494			/*
495			* If if is an ANNOUNCE message, we go through the
496			* request table to see if a tcp port has already
497			* been redirected for this socket. If not, we solisten()
498			* a new socket and add this entry to the table.
499			* The port number of the tcp socket and our IP
500			* are put to the addr field of the message structures.
501			* Then a LEAVE_INVITE is sent to both local daemon
502			* ports, 517 and 518. This is why we have two copies
503			* of the message, one in old talk and one in new talk
504			* format.
505			*/
506
507			if (type == ANNOUNCE) {
508			int s;
509			u_short temp_port;
510
511			for(req = req_tbl; req; req = req->next)
512			if (so == req->udp_so)
513			break; /* found it */
514
515			if (!req) { /* no entry for so, create new */
516			req = (struct talk_request *)
517			malloc(sizeof(struct talk_request));
518			req->udp_so = so;
519			req->tcp_so = solisten(0,
520			OTOSIN(omsg, addr)->sin_addr.s_addr,
521			OTOSIN(omsg, addr)->sin_port,
522			SS_FACCEPTONCE);
523			req->next = req_tbl;
524			req_tbl = req;
525			}
526
527			/* replace port number in addr field */
528			addrlen = sizeof(addr);
529			getsockname(req->tcp_so->s,
530			(struct sockaddr *) &addr,
531			&addrlen);
532			OTOSIN(omsg, addr)->sin_port = addr.sin_port;
533			OTOSIN(omsg, addr)->sin_addr = our_addr;
534			OTOSIN(nmsg, addr)->sin_port = addr.sin_port;
535			OTOSIN(nmsg, addr)->sin_addr = our_addr;
536
537			/* send LEAVE_INVITEs */
538			temp_port = OTOSIN(omsg, ctl_addr)->sin_port;
539			OTOSIN(omsg, ctl_addr)->sin_port = 0;
540			OTOSIN(nmsg, ctl_addr)->sin_port = 0;
541			omsg->type = nmsg->type = LEAVE_INVITE;
542
543			s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
544			addr.sin_addr = our_addr;
545			addr.sin_family = AF_INET;
546			addr.sin_port = htons(517);
547			sendto(s, (char )omsg, sizeof(omsg), 0,
548			(struct sockaddr *)&addr, sizeof(addr));
549			addr.sin_port = htons(518);
550			sendto(s, (char )nmsg, sizeof(nmsg), 0,
551			(struct sockaddr *) &addr, sizeof(addr));
552			closesocket(s) ;
553
554			omsg->type = nmsg->type = ANNOUNCE;
555			OTOSIN(omsg, ctl_addr)->sin_port = temp_port;
556			OTOSIN(nmsg, ctl_addr)->sin_port = temp_port;
557			}
558
559			/*
560			* If it is a DELETE message, we send a copy to the
561			* local daemons. Then we delete the entry corresponding
562			* to our socket from the request table.
563			*/
564
565			if (type == DELETE) {
566			struct talk_request temp_req, req_next;
567			int s;
568			u_short temp_port;
569
570			temp_port = OTOSIN(omsg, ctl_addr)->sin_port;
571			OTOSIN(omsg, ctl_addr)->sin_port = 0;
572			OTOSIN(nmsg, ctl_addr)->sin_port = 0;
573
574			s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
575			addr.sin_addr = our_addr;
576			addr.sin_family = AF_INET;
577			addr.sin_port = htons(517);
578			sendto(s, (char )omsg, sizeof(omsg), 0,
579			(struct sockaddr *)&addr, sizeof(addr));
580			addr.sin_port = htons(518);
581			sendto(s, (char )nmsg, sizeof(nmsg), 0,
582			(struct sockaddr *)&addr, sizeof(addr));
583			closesocket(s);
584
585			OTOSIN(omsg, ctl_addr)->sin_port = temp_port;
586			OTOSIN(nmsg, ctl_addr)->sin_port = temp_port;
587
588			/* delete table entry */
589			if (so == req_tbl->udp_so) {
590			temp_req = req_tbl;
591			req_tbl = req_tbl->next;
592			free(temp_req);
593			} else {
594			temp_req = req_tbl;
595			for(req = req_tbl->next; req; req = req_next) {
596			req_next = req->next;
597			if (so == req->udp_so) {
598			temp_req->next = req_next;
599			free(req);
600			break;
601			} else {
602			temp_req = req;
603			}
604			}
605			}
606			}
607
608			return;
609			#endif
610
611			case EMU_CUSEEME:
612
613			/*
614			* Cu-SeeMe emulation.
615			* Hopefully the packet is more that 16 bytes long. We don't
616			* do any other tests, just replace the address and port
617			* fields.
618			*/
619			if (m->m_len >= sizeof (*cu_head)) {
620			if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0)
621			return;
622			cu_head = mtod(m, struct cu_header *);
623	gbeauche	1.2	cu_head->s_port = addr.sin_port;
624	gbeauche	1.4	cu_head->so_addr = our_addr.s_addr;
625	gbeauche	1.1	}
626
627			return;
628			}
629			}
630
631			struct socket *
632			udp_listen(port, laddr, lport, flags)
633			u_int port;
634			u_int32_t laddr;
635			u_int lport;
636			int flags;
637			{
638			struct sockaddr_in addr;
639			struct socket *so;
640	cebix	1.3	socklen_t addrlen = sizeof(struct sockaddr_in);
641			int opt = 1;
642	gbeauche	1.1
643			if ((so = socreate()) == NULL) {
644			free(so);
645			return NULL;
646			}
647			so->s = socket(AF_INET,SOCK_DGRAM,0);
648			so->so_expire = curtime + SO_EXPIRE;
649			insque(so,&udb);
650
651			addr.sin_family = AF_INET;
652			addr.sin_addr.s_addr = INADDR_ANY;
653			addr.sin_port = port;
654
655			if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) {
656			udp_detach(so);
657			return NULL;
658			}
659			setsockopt(so->s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int));
660			/* setsockopt(so->s,SOL_SOCKET,SO_OOBINLINE,(char )&opt,sizeof(int)); /
661
662			getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
663			so->so_fport = addr.sin_port;
664			if (addr.sin_addr.s_addr == 0 \|\| addr.sin_addr.s_addr == loopback_addr.s_addr)
665	gbeauche	1.5	so->so_faddr = alias_addr;
666	gbeauche	1.1	else
667			so->so_faddr = addr.sin_addr;
668
669			so->so_lport = lport;
670			so->so_laddr.s_addr = laddr;
671			if (flags != SS_FACCEPTONCE)
672			so->so_expire = 0;
673
674			so->so_state = SS_ISFCONNECTED;
675
676			return so;
677			}