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
  74         DEBUG_CALL("udp_input");
  75         DEBUG_ARG("m = %lx", (long)m);
  76         DEBUG_ARG("iphlen = %d", iphlen);
  77
  78         /*
  79          * Strip IP options, if any; should skip this,
  80          * make available to user, and use on returned packets,
  81          * but we don't yet have a way to check the checksum
  82          * with options still present.
  83          */
  84         if(iphlen > sizeof(struct ip)) {
  85                 ip_stripoptions(m, (struct mbuf *)0);
  86                 iphlen = sizeof(struct ip);
  87         }
  88
  89         /*
  90          * Get IP and UDP header together in first mbuf.
  91          */
  92         ip = mtod(m, struct ip *);
  93         uh = (struct udphdr *)((caddr_t)ip + iphlen);
  94
  95         /*
  96          * Make mbuf data length reflect UDP length.
  97          * If not enough data to reflect UDP length, drop.
  98          */
  99         len = ntohs((uint16_t)uh->uh_ulen);
 100
 101         if (ip->ip_len != len) {
 102                 if (len > ip->ip_len) {
 103                         goto bad;
 104                 }
 105                 m_adj(m, len - ip->ip_len);
 106                 ip->ip_len = len;
 107         }
 108
 109         /*
 110          * Save a copy of the IP header in case we want restore it
 111          * for sending an ICMP error message in response.
 112          */
 113         save_ip = *ip;
 114         save_ip.ip_len+= iphlen;         /* tcp_input subtracts this */
 115
 116         /*
 117          * Checksum extended UDP header and data.
 118          */
 119         if (uh->uh_sum) {
 120       memset(&((struct ipovly *)ip)->ih_mbuf, 0, sizeof(struct mbuf_ptr));
 121           ((struct ipovly *)ip)->ih_x1 = 0;
 122           ((struct ipovly *)ip)->ih_len = uh->uh_ulen;
 123           if(cksum(m, len + sizeof(struct ip))) {
 124             goto bad;
 125           }
 126         }
 127
 128         /*
 129          *  handle DHCP/BOOTP
 130          */
 131         if (ntohs(uh->uh_dport) == BOOTP_SERVER &&
 132             (ip->ip_dst.s_addr == slirp->vhost_addr.s_addr ||
 133              ip->ip_dst.s_addr == 0xffffffff)) {
 134                 bootp_input(m);
 135                 goto bad;
 136             }
 137
 138         /*
 139          *  handle TFTP
 140          */
 141         if (ntohs(uh->uh_dport) == TFTP_SERVER &&
 142             ip->ip_dst.s_addr == slirp->vhost_addr.s_addr) {
 143             tftp_input(m);
 144             goto bad;
 145         }
 146
 147         if (slirp->restricted) {
 148             goto bad;
 149         }
 150
 151         /*
 152          * Locate pcb for datagram.
 153          */
 154         so = slirp->udp_last_so;
 155         if (so->so_lport != uh->uh_sport ||
 156             so->so_laddr.s_addr != ip->ip_src.s_addr) {
 157                 struct socket *tmp;
 158
 159                 for (tmp = slirp->udb.so_next; tmp != &slirp->udb;
 160                      tmp = tmp->so_next) {
 161                         if (tmp->so_lport == uh->uh_sport &&
 162                             tmp->so_laddr.s_addr == ip->ip_src.s_addr) {
 163                                 so = tmp;
 164                                 break;
 165                         }
 166                 }
 167                 if (tmp == &slirp->udb) {
 168                   so = NULL;
 169                 } else {
 170                   slirp->udp_last_so = so;
 171                 }
 172         }
 173
 174         if (so == NULL) {
 175           /*
 176            * If there's no socket for this packet,
 177            * create one
 178            */
 179           so = socreate(slirp);
 180           if (!so) {
 181               goto bad;
 182           }
 183           if(udp_attach(so) == -1) {
 184             DEBUG_MISC((dfd," udp_attach errno = %d-%s\n",
 185                         errno,strerror(errno)));
 186             sofree(so);
 187             goto bad;
 188           }
 189
 190           /*
 191            * Setup fields
 192            */
 193           so->so_laddr = ip->ip_src;
 194           so->so_lport = uh->uh_sport;
 195
 196           if ((so->so_iptos = udp_tos(so)) == 0)
 197             so->so_iptos = ip->ip_tos;
 198
 199           /*
 200            * XXXXX Here, check if it's in udpexec_list,
 201            * and if it is, do the fork_exec() etc.
 202            */
 203         }
 204
 205         so->so_faddr = ip->ip_dst; /* XXX */
 206         so->so_fport = uh->uh_dport; /* XXX */
 207
 208         iphlen += sizeof(struct udphdr);
 209         m->m_len -= iphlen;
 210         m->m_data += iphlen;
 211
 212         /*
 213          * Now we sendto() the packet.
 214          */
 215         if(sosendto(so,m) == -1) {
 216           m->m_len += iphlen;
 217           m->m_data -= iphlen;
 218           *ip=save_ip;
 219           DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno,strerror(errno)));
 220           icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
 221         }
 222
 223         m_free(so->so_m);   /* used for ICMP if error on sorecvfrom */
 224
 225         /* restore the orig mbuf packet */
 226         m->m_len += iphlen;
 227         m->m_data -= iphlen;
 228         *ip=save_ip;
 229         so->so_m=m;         /* ICMP backup */
 230
 231         return;
 232 bad:
 233         m_free(m);
 234 }
 235
 236 int udp_output2(struct socket *so, struct mbuf *m,
 237                 struct sockaddr_in *saddr, struct sockaddr_in *daddr,
 238                 int iptos)
 239 {
 240         register struct udpiphdr *ui;
 241         int error = 0;
 242
 243         DEBUG_CALL("udp_output");
 244         DEBUG_ARG("so = %lx", (long)so);
 245         DEBUG_ARG("m = %lx", (long)m);
 246         DEBUG_ARG("saddr = %lx", (long)saddr->sin_addr.s_addr);
 247         DEBUG_ARG("daddr = %lx", (long)daddr->sin_addr.s_addr);
 248
 249         /*
 250          * Adjust for header
 251          */
 252         m->m_data -= sizeof(struct udpiphdr);
 253         m->m_len += sizeof(struct udpiphdr);
 254
 255         /*
 256          * Fill in mbuf with extended UDP header
 257          * and addresses and length put into network format.
 258          */
 259         ui = mtod(m, struct udpiphdr *);
 260     memset(&ui->ui_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr));
 261         ui->ui_x1 = 0;
 262         ui->ui_pr = IPPROTO_UDP;
 263         ui->ui_len = htons(m->m_len - sizeof(struct ip));
 264         /* XXXXX Check for from-one-location sockets, or from-any-location sockets */
 265         ui->ui_src = saddr->sin_addr;
 266         ui->ui_dst = daddr->sin_addr;
 267         ui->ui_sport = saddr->sin_port;
 268         ui->ui_dport = daddr->sin_port;
 269         ui->ui_ulen = ui->ui_len;
 270
 271         /*
 272          * Stuff checksum and output datagram.
 273          */
 274         ui->ui_sum = 0;
 275         if ((ui->ui_sum = cksum(m, m->m_len)) == 0)
 276                 ui->ui_sum = 0xffff;
 277         ((struct ip *)ui)->ip_len = m->m_len;
 278
 279         ((struct ip *)ui)->ip_ttl = IPDEFTTL;
 280         ((struct ip *)ui)->ip_tos = iptos;
 281
 282         error = ip_output(so, m);
 283
 284         return (error);
 285 }
 286
 287 int udp_output(struct socket *so, struct mbuf *m,
 288                struct sockaddr_in *addr)
 289
 290 {
 291     Slirp *slirp = so->slirp;
 292     struct sockaddr_in saddr, daddr;
 293
 294     saddr = *addr;
 295     if ((so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) ==
 296         slirp->vnetwork_addr.s_addr) {
 297         uint32_t inv_mask = ~slirp->vnetwork_mask.s_addr;
 298
 299         if ((so->so_faddr.s_addr & inv_mask) == inv_mask) {
 300             saddr.sin_addr = slirp->vhost_addr;
 301         } else if (addr->sin_addr.s_addr == loopback_addr.s_addr ||
 302                    so->so_faddr.s_addr != slirp->vhost_addr.s_addr) {
 303             saddr.sin_addr = so->so_faddr;
 304         }
 305     }
 306     daddr.sin_addr = so->so_laddr;
 307     daddr.sin_port = so->so_lport;
 308
 309     return udp_output2(so, m, &saddr, &daddr, so->so_iptos);
 310 }
 311
 312 int
 313 udp_attach(struct socket *so)
 314 {
 315   if((so->s = qemu_socket(AF_INET,SOCK_DGRAM,0)) != -1) {
 316     so->so_expire = curtime + SO_EXPIRE;
 317     insque(so, &so->slirp->udb);
 318   }
 319   return(so->s);
 320 }
 321
 322 void
 323 udp_detach(struct socket *so)
 324 {
 325         closesocket(so->s);
 326         sofree(so);
 327 }
 328
 329 static const struct tos_t udptos[] = {
 330         {0, 53, IPTOS_LOWDELAY, 0},                     /* DNS */
 331         {0, 0, 0, 0}
 332 };
 333
 334 static uint8_t
 335 udp_tos(struct socket *so)
 336 {
 337         int i = 0;
 338
 339         while(udptos[i].tos) {
 340                 if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) ||
 341                     (udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {
 342                         so->so_emu = udptos[i].emu;
 343                         return udptos[i].tos;
 344                 }
 345                 i++;
 346         }
 347
 348         return 0;
 349 }
 350
 351 struct socket *
 352 udp_listen(Slirp *slirp, uint32_t haddr, u_int hport, uint32_t laddr,
 353            u_int lport, int flags)
 354 {
 355         struct sockaddr_in addr;
 356         struct socket *so;
 357         socklen_t addrlen = sizeof(struct sockaddr_in);
 358
 359         so = socreate(slirp);
 360         if (!so) {
 361             return NULL;
 362         }
 363         so->s = qemu_socket(AF_INET,SOCK_DGRAM,0);
 364         so->so_expire = curtime + SO_EXPIRE;
 365         insque(so, &slirp->udb);
 366
 367         addr.sin_family = AF_INET;
 368         addr.sin_addr.s_addr = haddr;
 369         addr.sin_port = hport;
 370
 371         if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) {
 372                 udp_detach(so);
 373                 return NULL;
 374         }
 375         socket_set_fast_reuse(so->s);
 376
 377         getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
 378         so->so_fport = addr.sin_port;
 379         if (addr.sin_addr.s_addr == 0 ||
 380             addr.sin_addr.s_addr == loopback_addr.s_addr) {
 381            so->so_faddr = slirp->vhost_addr;
 382         } else {
 383            so->so_faddr = addr.sin_addr;
 384         }
 385         so->so_lport = lport;
 386         so->so_laddr.s_addr = laddr;
 387         if (flags != SS_FACCEPTONCE)
 388            so->so_expire = 0;
 389
 390         so->so_state &= SS_PERSISTENT_MASK;
 391         so->so_state |= SS_ISFCONNECTED | flags;
 392
 393         return so;
 394 }