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 /* m->m_data  points at ip packet header
  53  * m->m_len   length ip packet
  54  * ip->ip_len length data (IPDU)
  55  */
  56 void
  57 udp_input(register struct mbuf *m, int iphlen)
  58 {
  59         Slirp *slirp = m->slirp;
  60         register struct ip *ip;
  61         register struct udphdr *uh;
  62         int len;
  63         struct ip save_ip;
  64         struct socket *so;
  65
  66         DEBUG_CALL("udp_input");
  67         DEBUG_ARG("m = %lx", (long)m);
  68         DEBUG_ARG("iphlen = %d", iphlen);
  69
  70         /*
  71          * Strip IP options, if any; should skip this,
  72          * make available to user, and use on returned packets,
  73          * but we don't yet have a way to check the checksum
  74          * with options still present.
  75          */
  76         if(iphlen > sizeof(struct ip)) {
  77                 ip_stripoptions(m, (struct mbuf *)0);
  78                 iphlen = sizeof(struct ip);
  79         }
  80
  81         /*
  82          * Get IP and UDP header together in first mbuf.
  83          */
  84         ip = mtod(m, struct ip *);
  85         uh = (struct udphdr *)((caddr_t)ip + iphlen);
  86
  87         /*
  88          * Make mbuf data length reflect UDP length.
  89          * If not enough data to reflect UDP length, drop.
  90          */
  91         len = ntohs((uint16_t)uh->uh_ulen);
  92
  93         if (ip->ip_len != len) {
  94                 if (len > ip->ip_len) {
  95                         goto bad;
  96                 }
  97                 m_adj(m, len - ip->ip_len);
  98                 ip->ip_len = len;
  99         }
 100
 101         /*
 102          * Save a copy of the IP header in case we want restore it
 103          * for sending an ICMP error message in response.
 104          */
 105         save_ip = *ip;
 106         save_ip.ip_len+= iphlen;         /* tcp_input subtracts this */
 107
 108         /*
 109          * Checksum extended UDP header and data.
 110          */
 111         if (uh->uh_sum) {
 112       memset(&((struct ipovly *)ip)->ih_mbuf, 0, sizeof(struct mbuf_ptr));
 113           ((struct ipovly *)ip)->ih_x1 = 0;
 114           ((struct ipovly *)ip)->ih_len = uh->uh_ulen;
 115           if(cksum(m, len + sizeof(struct ip))) {
 116             goto bad;
 117           }
 118         }
 119
 120         /*
 121          *  handle DHCP/BOOTP
 122          */
 123         if (ntohs(uh->uh_dport) == BOOTP_SERVER &&
 124             (ip->ip_dst.s_addr == slirp->vhost_addr.s_addr ||
 125              ip->ip_dst.s_addr == 0xffffffff)) {
 126                 bootp_input(m);
 127                 goto bad;
 128             }
 129
 130         /*
 131          *  handle TFTP
 132          */
 133         if (ntohs(uh->uh_dport) == TFTP_SERVER &&
 134             ip->ip_dst.s_addr == slirp->vhost_addr.s_addr) {
 135             tftp_input(m);
 136             goto bad;
 137         }
 138
 139         if (slirp->restricted) {
 140             goto bad;
 141         }
 142
 143         /*
 144          * Locate pcb for datagram.
 145          */
 146         so = slirp->udp_last_so;
 147         if (so->so_lport != uh->uh_sport ||
 148             so->so_laddr.s_addr != ip->ip_src.s_addr) {
 149                 struct socket *tmp;
 150
 151                 for (tmp = slirp->udb.so_next; tmp != &slirp->udb;
 152                      tmp = tmp->so_next) {
 153                         if (tmp->so_lport == uh->uh_sport &&
 154                             tmp->so_laddr.s_addr == ip->ip_src.s_addr) {
 155                                 so = tmp;
 156                                 break;
 157                         }
 158                 }
 159                 if (tmp == &slirp->udb) {
 160                   so = NULL;
 161                 } else {
 162                   slirp->udp_last_so = so;
 163                 }
 164         }
 165
 166         if (so == NULL) {
 167           /*
 168            * If there's no socket for this packet,
 169            * create one
 170            */
 171           so = socreate(slirp);
 172           if (!so) {
 173               goto bad;
 174           }
 175           if(udp_attach(so) == -1) {
 176             DEBUG_MISC((dfd," udp_attach errno = %d-%s\n",
 177                         errno,strerror(errno)));
 178             sofree(so);
 179             goto bad;
 180           }
 181
 182           /*
 183            * Setup fields
 184            */
 185           so->so_laddr = ip->ip_src;
 186           so->so_lport = uh->uh_sport;
 187
 188           if ((so->so_iptos = udp_tos(so)) == 0)
 189             so->so_iptos = ip->ip_tos;
 190
 191           /*
 192            * XXXXX Here, check if it's in udpexec_list,
 193            * and if it is, do the fork_exec() etc.
 194            */
 195         }
 196
 197         so->so_faddr = ip->ip_dst; /* XXX */
 198         so->so_fport = uh->uh_dport; /* XXX */
 199
 200         iphlen += sizeof(struct udphdr);
 201         m->m_len -= iphlen;
 202         m->m_data += iphlen;
 203
 204         /*
 205          * Now we sendto() the packet.
 206          */
 207         if(sosendto(so,m) == -1) {
 208           m->m_len += iphlen;
 209           m->m_data -= iphlen;
 210           *ip=save_ip;
 211           DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno,strerror(errno)));
 212           icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
 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         return;
 227 }
 228
 229 int udp_output2(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 = %lx", (long)so);
 238         DEBUG_ARG("m = %lx", (long)m);
 239         DEBUG_ARG("saddr = %lx", (long)saddr->sin_addr.s_addr);
 240         DEBUG_ARG("daddr = %lx", (long)daddr->sin_addr.s_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 udp_output(struct socket *so, struct mbuf *m,
 281                struct sockaddr_in *addr)
 282
 283 {
 284     Slirp *slirp = so->slirp;
 285     struct sockaddr_in saddr, daddr;
 286
 287     saddr = *addr;
 288     if ((so->so_faddr.s_addr & slirp->vnetwork_mask.s_addr) ==
 289         slirp->vnetwork_addr.s_addr) {
 290         uint32_t inv_mask = ~slirp->vnetwork_mask.s_addr;
 291
 292         if ((so->so_faddr.s_addr & inv_mask) == inv_mask) {
 293             saddr.sin_addr = slirp->vhost_addr;
 294         } else if (addr->sin_addr.s_addr == loopback_addr.s_addr ||
 295                    so->so_faddr.s_addr != slirp->vhost_addr.s_addr) {
 296             saddr.sin_addr = so->so_faddr;
 297         }
 298     }
 299     daddr.sin_addr = so->so_laddr;
 300     daddr.sin_port = so->so_lport;
 301
 302     return udp_output2(so, m, &saddr, &daddr, so->so_iptos);
 303 }
 304
 305 int
 306 udp_attach(struct socket *so)
 307 {
 308   if((so->s = qemu_socket(AF_INET,SOCK_DGRAM,0)) != -1) {
 309     so->so_expire = curtime + SO_EXPIRE;
 310     insque(so, &so->slirp->udb);
 311   }
 312   return(so->s);
 313 }
 314
 315 void
 316 udp_detach(struct socket *so)
 317 {
 318         closesocket(so->s);
 319         sofree(so);
 320 }
 321
 322 static const struct tos_t udptos[] = {
 323         {0, 53, IPTOS_LOWDELAY, 0},                     /* DNS */
 324         {0, 0, 0, 0}
 325 };
 326
 327 static uint8_t
 328 udp_tos(struct socket *so)
 329 {
 330         int i = 0;
 331
 332         while(udptos[i].tos) {
 333                 if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) ||
 334                     (udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {
 335                         so->so_emu = udptos[i].emu;
 336                         return udptos[i].tos;
 337                 }
 338                 i++;
 339         }
 340
 341         return 0;
 342 }
 343
 344 struct socket *
 345 udp_listen(Slirp *slirp, uint32_t haddr, u_int hport, uint32_t laddr,
 346            u_int lport, int flags)
 347 {
 348         struct sockaddr_in addr;
 349         struct socket *so;
 350         socklen_t addrlen = sizeof(struct sockaddr_in), opt = 1;
 351
 352         so = socreate(slirp);
 353         if (!so) {
 354             return NULL;
 355         }
 356         so->s = qemu_socket(AF_INET,SOCK_DGRAM,0);
 357         so->so_expire = curtime + SO_EXPIRE;
 358         insque(so, &slirp->udb);
 359
 360         addr.sin_family = AF_INET;
 361         addr.sin_addr.s_addr = haddr;
 362         addr.sin_port = hport;
 363
 364         if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) {
 365                 udp_detach(so);
 366                 return NULL;
 367         }
 368         setsockopt(so->s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int));
 369
 370         getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
 371         so->so_fport = addr.sin_port;
 372         if (addr.sin_addr.s_addr == 0 ||
 373             addr.sin_addr.s_addr == loopback_addr.s_addr) {
 374            so->so_faddr = slirp->vhost_addr;
 375         } else {
 376            so->so_faddr = addr.sin_addr;
 377         }
 378         so->so_lport = lport;
 379         so->so_laddr.s_addr = laddr;
 380         if (flags != SS_FACCEPTONCE)
 381            so->so_expire = 0;
 382
 383         so->so_state &= SS_PERSISTENT_MASK;
 384         so->so_state |= SS_ISFCONNECTED | flags;
 385
 386         return so;
 387 }