slirp/udp.c

   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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  *      @(#)udp_usrreq.c        8.4 (Berkeley) 1/21/94
  30  * udp_usrreq.c,v 1.4 1994/10/02 17:48:45 phk Exp
  31  */
  32
  33 /*
  34  * Changes and additions relating to SLiRP
  35  * Copyright (c) 1995 Danny Gasparovski.
  36  *
  37  * Please read the file COPYRIGHT for the
  38  * terms and conditions of the copyright.
  39  */
  40
  41 #include <slirp.h>
  42 #include "ip_icmp.h"
  43
  44 static uint8_t udp_tos(struct socket *so);
  45
  46 void
  47 udp_init(Slirp *slirp)
  48 {
  49     slirp->udb.so_next = slirp->udb.so_prev = &slirp->udb;
  50     slirp->udp_last_so = &slirp->udb;
  51 }
  52
  53 void udp_cleanup(Slirp *slirp)
  54 {
  55     while (slirp->udb.so_next != &slirp->udb) {
  56         udp_detach(slirp->udb.so_next);
  57     }
  58 }
  59
  60 /* m->m_data  points at ip packet header
  61  * m->m_len   length ip packet
  62  * ip->ip_len length data (IPDU)
  63  */
  64 void
  65 udp_input(register struct mbuf *m, int iphlen)
  66 {
  67         Slirp *slirp = m->slirp;
  68         register struct ip *ip;
  69         register struct udphdr *uh;
  70         int len;
  71         struct ip save_ip;
  72         struct socket *so;
  73         struct sockaddr_storage lhost;
  74         struct sockaddr_in *lhost4;
  75
  76         DEBUG_CALL("udp_input");
  77         DEBUG_ARG("m = %p", m);
  78         DEBUG_ARG("iphlen = %d", iphlen);
  79
  80         /*
  81          * Strip IP options, if any; should skip this,
  82          * make available to user, and use on returned packets,
  83          * but we don't yet have a way to check the checksum
  84          * with options still present.
  85          */
  86         if(iphlen > sizeof(struct ip)) {
  87                 ip_stripoptions(m, (struct mbuf *)0);
  88                 iphlen = sizeof(struct ip);
  89         }
  90
  91         /*
  92          * Get IP and UDP header together in first mbuf.
  93          */
  94         ip = mtod(m, struct ip *);
  95         uh = (struct udphdr *)((caddr_t)ip + iphlen);
  96
  97         /*
  98          * Make mbuf data length reflect UDP length.
  99          * If not enough data to reflect UDP length, drop.
 100          */
 101         len = ntohs((uint16_t)uh->uh_ulen);
 102
 103         if (ip->ip_len != len) {
 104                 if (len > ip->ip_len) {
 105                         goto bad;
 106                 }
 107                 m_adj(m, len - ip->ip_len);
 108                 ip->ip_len = len;
 109         }
 110
 111         /*
 112          * Save a copy of the IP header in case we want restore it
 113          * for sending an ICMP error message in response.
 114          */
 115         save_ip = *ip;
 116         save_ip.ip_len+= iphlen;         /* tcp_input subtracts this */
 117
 118         /*
 119          * Checksum extended UDP header and data.
 120          */
 121         if (uh->uh_sum) {
 122       memset(&((struct ipovly *)ip)->ih_mbuf, 0, sizeof(struct mbuf_ptr));
 123           ((struct ipovly *)ip)->ih_x1 = 0;
 124           ((struct ipovly *)ip)->ih_len = uh->uh_ulen;
 125           if(cksum(m, len + sizeof(struct ip))) {
 126             goto bad;
 127           }
 128         }
 129
 130         /*
 131          *  handle DHCP/BOOTP
 132          */
 133         if (ntohs(uh->uh_dport) == BOOTP_SERVER &&
 134             (ip->ip_dst.s_addr == slirp->vhost_addr.s_addr ||
 135              ip->ip_dst.s_addr == 0xffffffff)) {
 136                 bootp_input(m);
 137                 goto bad;
 138             }
 139
 140         /*
 141          *  handle TFTP
 142          */
 143         if (ntohs(uh->uh_dport) == TFTP_SERVER &&
 144             ip->ip_dst.s_addr == slirp->vhost_addr.s_addr) {
 145             tftp_input(m);
 146             goto bad;
 147         }
 148
 149         if (slirp->restricted) {
 150             goto bad;
 151         }
 152
 153         /*
 154          * Locate pcb for datagram.
 155          */
 156         lhost.ss_family = AF_INET;
 157         lhost4 = (struct sockaddr_in *) &lhost;
 158         lhost4->sin_addr = ip->ip_src;
 159         lhost4->sin_port = uh->uh_sport;
 160
 161         so = solookup(&slirp->udp_last_so, &slirp->udb, &lhost, NULL);
 162
 163         if (so == NULL) {
 164           /*
 165            * If there's no socket for this packet,
 166            * create one
 167            */
 168           so = socreate(slirp);
 169           if (!so) {
 170               goto bad;
 171           }
 172           if(udp_attach(so) == -1) {
 173             DEBUG_MISC((dfd," udp_attach errno = %d-%s\n",
 174                         errno,strerror(errno)));
 175             sofree(so);
 176             goto bad;
 177           }
 178
 179           /*
 180            * Setup fields
 181            */
 182           so->so_lfamily = AF_INET;
 183           so->so_laddr = ip->ip_src;
 184           so->so_lport = uh->uh_sport;
 185
 186           if ((so->so_iptos = udp_tos(so)) == 0)
 187             so->so_iptos = ip->ip_tos;
 188
 189           /*
 190            * XXXXX Here, check if it's in udpexec_list,
 191            * and if it is, do the fork_exec() etc.
 192            */
 193         }
 194
 195         so->so_ffamily = AF_INET;
 196         so->so_faddr = ip->ip_dst; /* XXX */
 197         so->so_fport = uh->uh_dport; /* XXX */
 198
 199         iphlen += sizeof(struct udphdr);
 200         m->m_len -= iphlen;
 201         m->m_data += iphlen;
 202
 203         /*
 204          * Now we sendto() the packet.
 205          */
 206         if(sosendto(so,m) == -1) {
 207           m->m_len += iphlen;
 208           m->m_data -= iphlen;
 209           *ip=save_ip;
 210           DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno,strerror(errno)));
 211           icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
 212           goto bad;
 213         }
 214
 215         m_free(so->so_m);   /* used for ICMP if error on sorecvfrom */
 216
 217         /* restore the orig mbuf packet */
 218         m->m_len += iphlen;
 219         m->m_data -= iphlen;
 220         *ip=save_ip;
 221         so->so_m=m;         /* ICMP backup */
 222
 223         return;
 224 bad:
 225         m_free(m);
 226 }
 227
 228 int udp_output(struct socket *so, struct mbuf *m,
 229                 struct sockaddr_in *saddr, struct sockaddr_in *daddr,
 230                 int iptos)
 231 {
 232         register struct udpiphdr *ui;
 233         int error = 0;
 234
 235         DEBUG_CALL("udp_output");
 236         DEBUG_ARG("so = %p", so);
 237         DEBUG_ARG("m = %p", m);
 238         DEBUG_ARG("saddr = %lx", (long)saddr->sin_addr.s_addr);
 239         DEBUG_ARG("daddr = %lx", (long)daddr->sin_addr.s_addr);
 240
 241         /*
 242          * Adjust for header
 243          */
 244         m->m_data -= sizeof(struct udpiphdr);
 245         m->m_len += sizeof(struct udpiphdr);
 246
 247         /*
 248          * Fill in mbuf with extended UDP header
 249          * and addresses and length put into network format.
 250          */
 251         ui = mtod(m, struct udpiphdr *);
 252     memset(&ui->ui_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr));
 253         ui->ui_x1 = 0;
 254         ui->ui_pr = IPPROTO_UDP;
 255         ui->ui_len = htons(m->m_len - sizeof(struct ip));
 256         /* XXXXX Check for from-one-location sockets, or from-any-location sockets */
 257         ui->ui_src = saddr->sin_addr;
 258         ui->ui_dst = daddr->sin_addr;
 259         ui->ui_sport = saddr->sin_port;
 260         ui->ui_dport = daddr->sin_port;
 261         ui->ui_ulen = ui->ui_len;
 262
 263         /*
 264          * Stuff checksum and output datagram.
 265          */
 266         ui->ui_sum = 0;
 267         if ((ui->ui_sum = cksum(m, m->m_len)) == 0)
 268                 ui->ui_sum = 0xffff;
 269         ((struct ip *)ui)->ip_len = m->m_len;
 270
 271         ((struct ip *)ui)->ip_ttl = IPDEFTTL;
 272         ((struct ip *)ui)->ip_tos = iptos;
 273
 274         error = ip_output(so, m);
 275
 276         return (error);
 277 }
 278
 279 int
 280 udp_attach(struct socket *so)
 281 {
 282   if((so->s = qemu_socket(AF_INET,SOCK_DGRAM,0)) != -1) {
 283     so->so_expire = curtime + SO_EXPIRE;
 284     insque(so, &so->slirp->udb);
 285   }
 286   return(so->s);
 287 }
 288
 289 void
 290 udp_detach(struct socket *so)
 291 {
 292         closesocket(so->s);
 293         sofree(so);
 294 }
 295
 296 static const struct tos_t udptos[] = {
 297         {0, 53, IPTOS_LOWDELAY, 0},                     /* DNS */
 298         {0, 0, 0, 0}
 299 };
 300
 301 static uint8_t
 302 udp_tos(struct socket *so)
 303 {
 304         int i = 0;
 305
 306         while(udptos[i].tos) {
 307                 if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) ||
 308                     (udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {
 309                         so->so_emu = udptos[i].emu;
 310                         return udptos[i].tos;
 311                 }
 312                 i++;
 313         }
 314
 315         return 0;
 316 }
 317
 318 struct socket *
 319 udp_listen(Slirp *slirp, uint32_t haddr, u_int hport, uint32_t laddr,
 320            u_int lport, int flags)
 321 {
 322         struct sockaddr_in addr;
 323         struct socket *so;
 324         socklen_t addrlen = sizeof(struct sockaddr_in);
 325
 326         so = socreate(slirp);
 327         if (!so) {
 328             return NULL;
 329         }
 330         so->s = qemu_socket(AF_INET,SOCK_DGRAM,0);
 331         so->so_expire = curtime + SO_EXPIRE;
 332         insque(so, &slirp->udb);
 333
 334         addr.sin_family = AF_INET;
 335         addr.sin_addr.s_addr = haddr;
 336         addr.sin_port = hport;
 337
 338         if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) {
 339                 udp_detach(so);
 340                 return NULL;
 341         }
 342         socket_set_fast_reuse(so->s);
 343
 344         getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
 345         so->fhost.sin = addr;
 346         sotranslate_accept(so);
 347         so->so_lfamily = AF_INET;
 348         so->so_lport = lport;
 349         so->so_laddr.s_addr = laddr;
 350         if (flags != SS_FACCEPTONCE)
 351            so->so_expire = 0;
 352
 353         so->so_state &= SS_PERSISTENT_MASK;
 354         so->so_state |= SS_ISFCONNECTED | flags;
 355
 356         return so;
 357 }