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 *)((char *)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         lhost.ss_family = AF_INET;
 131         lhost4 = (struct sockaddr_in *) &lhost;
 132         lhost4->sin_addr = ip->ip_src;
 133         lhost4->sin_port = uh->uh_sport;
 134
 135         /*
 136          *  handle DHCP/BOOTP
 137          */
 138         if (ntohs(uh->uh_dport) == BOOTP_SERVER &&
 139             (ip->ip_dst.s_addr == slirp->vhost_addr.s_addr ||
 140              ip->ip_dst.s_addr == 0xffffffff)) {
 141                 bootp_input(m);
 142                 goto bad;
 143             }
 144
 145         /*
 146          *  handle TFTP
 147          */
 148         if (ntohs(uh->uh_dport) == TFTP_SERVER &&
 149             ip->ip_dst.s_addr == slirp->vhost_addr.s_addr) {
 150             m->m_data += iphlen;
 151             m->m_len -= iphlen;
 152             tftp_input(&lhost, m);
 153             m->m_data -= iphlen;
 154             m->m_len += iphlen;
 155             goto bad;
 156         }
 157
 158         if (slirp->restricted) {
 159             goto bad;
 160         }
 161
 162         /*
 163          * Locate pcb for datagram.
 164          */
 165         so = solookup(&slirp->udp_last_so, &slirp->udb, &lhost, NULL);
 166
 167         if (so == NULL) {
 168           /*
 169            * If there's no socket for this packet,
 170            * create one
 171            */
 172           so = socreate(slirp);
 173           if (udp_attach(so, AF_INET) == -1) {
 174             DEBUG_MISC(" udp_attach errno = %d-%s", 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("udp tx errno = %d-%s", errno, strerror(errno));
 211           icmp_send_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, 0,
 212                           strerror(errno));
 213           goto bad;
 214         }
 215
 216         m_free(so->so_m);   /* used for ICMP if error on sorecvfrom */
 217
 218         /* restore the orig mbuf packet */
 219         m->m_len += iphlen;
 220         m->m_data -= iphlen;
 221         *ip=save_ip;
 222         so->so_m=m;         /* ICMP backup */
 223
 224         return;
 225 bad:
 226         m_free(m);
 227 }
 228
 229 int udp_output(struct socket *so, struct mbuf *m,
 230                 struct sockaddr_in *saddr, struct sockaddr_in *daddr,
 231                 int iptos)
 232 {
 233         register struct udpiphdr *ui;
 234         int error = 0;
 235
 236         DEBUG_CALL("udp_output");
 237         DEBUG_ARG("so = %p", so);
 238         DEBUG_ARG("m = %p", m);
 239         DEBUG_ARG("saddr = %s", inet_ntoa(saddr->sin_addr));
 240         DEBUG_ARG("daddr = %s", inet_ntoa(daddr->sin_addr));
 241
 242         /*
 243          * Adjust for header
 244          */
 245         m->m_data -= sizeof(struct udpiphdr);
 246         m->m_len += sizeof(struct udpiphdr);
 247
 248         /*
 249          * Fill in mbuf with extended UDP header
 250          * and addresses and length put into network format.
 251          */
 252         ui = mtod(m, struct udpiphdr *);
 253     memset(&ui->ui_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr));
 254         ui->ui_x1 = 0;
 255         ui->ui_pr = IPPROTO_UDP;
 256         ui->ui_len = htons(m->m_len - sizeof(struct ip));
 257         /* XXXXX Check for from-one-location sockets, or from-any-location sockets */
 258         ui->ui_src = saddr->sin_addr;
 259         ui->ui_dst = daddr->sin_addr;
 260         ui->ui_sport = saddr->sin_port;
 261         ui->ui_dport = daddr->sin_port;
 262         ui->ui_ulen = ui->ui_len;
 263
 264         /*
 265          * Stuff checksum and output datagram.
 266          */
 267         ui->ui_sum = 0;
 268         if ((ui->ui_sum = cksum(m, m->m_len)) == 0)
 269                 ui->ui_sum = 0xffff;
 270         ((struct ip *)ui)->ip_len = m->m_len;
 271
 272         ((struct ip *)ui)->ip_ttl = IPDEFTTL;
 273         ((struct ip *)ui)->ip_tos = iptos;
 274
 275         error = ip_output(so, m);
 276
 277         return (error);
 278 }
 279
 280 int
 281 udp_attach(struct socket *so, unsigned short af)
 282 {
 283   so->s = slirp_socket(af, SOCK_DGRAM, 0);
 284   if (so->s != -1) {
 285     so->so_expire = curtime + SO_EXPIRE;
 286     insque(so, &so->slirp->udb);
 287   }
 288   return(so->s);
 289 }
 290
 291 void
 292 udp_detach(struct socket *so)
 293 {
 294         so->slirp->cb->unregister_poll_fd(so->s, so->slirp->opaque);
 295         closesocket(so->s);
 296         sofree(so);
 297 }
 298
 299 static const struct tos_t udptos[] = {
 300         {0, 53, IPTOS_LOWDELAY, 0},                     /* DNS */
 301         {0, 0, 0, 0}
 302 };
 303
 304 static uint8_t
 305 udp_tos(struct socket *so)
 306 {
 307         int i = 0;
 308
 309         while(udptos[i].tos) {
 310                 if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) ||
 311                     (udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {
 312                         so->so_emu = udptos[i].emu;
 313                         return udptos[i].tos;
 314                 }
 315                 i++;
 316         }
 317
 318         return 0;
 319 }
 320
 321 struct socket *
 322 udp_listen(Slirp *slirp, uint32_t haddr, unsigned hport, uint32_t laddr,
 323            unsigned lport, int flags)
 324 {
 325         struct sockaddr_in addr;
 326         struct socket *so;
 327         socklen_t addrlen = sizeof(struct sockaddr_in);
 328
 329         so = socreate(slirp);
 330         so->s = slirp_socket(AF_INET,SOCK_DGRAM,0);
 331         if (so->s < 0) {
 332             sofree(so);
 333             return NULL;
 334         }
 335         so->so_expire = curtime + SO_EXPIRE;
 336         insque(so, &slirp->udb);
 337
 338         addr.sin_family = AF_INET;
 339         addr.sin_addr.s_addr = haddr;
 340         addr.sin_port = hport;
 341
 342         if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) {
 343                 udp_detach(so);
 344                 return NULL;
 345         }
 346         slirp_socket_set_fast_reuse(so->s);
 347
 348         getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
 349         so->fhost.sin = addr;
 350         sotranslate_accept(so);
 351         so->so_lfamily = AF_INET;
 352         so->so_lport = lport;
 353         so->so_laddr.s_addr = laddr;
 354         if (flags != SS_FACCEPTONCE)
 355            so->so_expire = 0;
 356
 357         so->so_state &= SS_PERSISTENT_MASK;
 358         so->so_state |= SS_ISFCONNECTED | flags;
 359
 360         return so;
 361 }