LXR qemu/slirp/src/udp.c

   1/* SPDX-License-Identifier: BSD-3-Clause */
   2/*
   3 * Copyright (c) 1982, 1986, 1988, 1990, 1993
   4 *      The Regents of the University of California.  All rights reserved.
   5 *
   6 * Redistribution and use in source and binary forms, with or without
   7 * modification, are permitted provided that the following conditions
   8 * are met:
   9 * 1. Redistributions of source code must retain the above copyright
  10 *    notice, this list of conditions and the following disclaimer.
  11 * 2. Redistributions in binary form must reproduce the above copyright
  12 *    notice, this list of conditions and the following disclaimer in the
  13 *    documentation and/or other materials provided with the distribution.
  14 * 3. Neither the name of the University nor the names of its contributors
  15 *    may be used to endorse or promote products derived from this software
  16 *    without specific prior written permission.
  17 *
  18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28 * SUCH DAMAGE.
  29 *
  30 *      @(#)udp_usrreq.c        8.4 (Berkeley) 1/21/94
  31 * udp_usrreq.c,v 1.4 1994/10/02 17:48:45 phk Exp
  32 */
  33
  34/*
  35 * Changes and additions relating to SLiRP
  36 * Copyright (c) 1995 Danny Gasparovski.
  37 *
  38 * Please read the file COPYRIGHT for the
  39 * terms and conditions of the copyright.
  40 */
  41
  42#include "slirp.h"
  43#include "ip_icmp.h"
  44
  45static uint8_t udp_tos(struct socket *so);
  46
  47void
  48udp_init(Slirp *slirp)
  49{
  50    slirp->udb.so_next = slirp->udb.so_prev = &slirp->udb;
  51    slirp->udp_last_so = &slirp->udb;
  52}
  53
  54void udp_cleanup(Slirp *slirp)
  55{
  56    while (slirp->udb.so_next != &slirp->udb) {
  57        udp_detach(slirp->udb.so_next);
  58    }
  59}
  60
  61/* m->m_data  points at ip packet header
  62 * m->m_len   length ip packet
  63 * ip->ip_len length data (IPDU)
  64 */
  65void
  66udp_input(register struct mbuf *m, int iphlen)
  67{
  68        Slirp *slirp = m->slirp;
  69        register struct ip *ip;
  70        register struct udphdr *uh;
  71        int len;
  72        struct ip save_ip;
  73        struct socket *so;
  74        struct sockaddr_storage lhost;
  75        struct sockaddr_in *lhost4;
  76
  77        DEBUG_CALL("udp_input");
  78        DEBUG_ARG("m = %p", m);
  79        DEBUG_ARG("iphlen = %d", iphlen);
  80
  81        /*
  82         * Strip IP options, if any; should skip this,
  83         * make available to user, and use on returned packets,
  84         * but we don't yet have a way to check the checksum
  85         * with options still present.
  86         */
  87        if(iphlen > sizeof(struct ip)) {
  88                ip_stripoptions(m, (struct mbuf *)0);
  89                iphlen = sizeof(struct ip);
  90        }
  91
  92        /*
  93         * Get IP and UDP header together in first mbuf.
  94         */
  95        ip = mtod(m, struct ip *);
  96        uh = (struct udphdr *)((char *)ip + iphlen);
  97
  98        /*
  99         * Make mbuf data length reflect UDP length.
 100         * If not enough data to reflect UDP length, drop.
 101         */
 102        len = ntohs((uint16_t)uh->uh_ulen);
 103
 104        if (ip->ip_len != len) {
 105                if (len > ip->ip_len) {
 106                        goto bad;
 107                }
 108                m_adj(m, len - ip->ip_len);
 109                ip->ip_len = len;
 110        }
 111
 112        /*
 113         * Save a copy of the IP header in case we want restore it
 114         * for sending an ICMP error message in response.
 115         */
 116        save_ip = *ip;
 117        save_ip.ip_len+= iphlen;         /* tcp_input subtracts this */
 118
 119        /*
 120         * Checksum extended UDP header and data.
 121         */
 122        if (uh->uh_sum) {
 123      memset(&((struct ipovly *)ip)->ih_mbuf, 0, sizeof(struct mbuf_ptr));
 124          ((struct ipovly *)ip)->ih_x1 = 0;
 125          ((struct ipovly *)ip)->ih_len = uh->uh_ulen;
 126          if(cksum(m, len + sizeof(struct ip))) {
 127            goto bad;
 128          }
 129        }
 130
 131        lhost.ss_family = AF_INET;
 132        lhost4 = (struct sockaddr_in *) &lhost;
 133        lhost4->sin_addr = ip->ip_src;
 134        lhost4->sin_port = uh->uh_sport;
 135
 136        /*
 137         *  handle DHCP/BOOTP
 138         */
 139        if (ntohs(uh->uh_dport) == BOOTP_SERVER &&
 140            (ip->ip_dst.s_addr == slirp->vhost_addr.s_addr ||
 141             ip->ip_dst.s_addr == 0xffffffff)) {
 142                bootp_input(m);
 143                goto bad;
 144            }
 145
 146        /*
 147         *  handle TFTP
 148         */
 149        if (ntohs(uh->uh_dport) == TFTP_SERVER &&
 150            ip->ip_dst.s_addr == slirp->vhost_addr.s_addr) {
 151            m->m_data += iphlen;
 152            m->m_len -= iphlen;
 153            tftp_input(&lhost, m);
 154            m->m_data -= iphlen;
 155            m->m_len += iphlen;
 156            goto bad;
 157        }
 158
 159        if (slirp->restricted) {
 160            goto bad;
 161        }
 162
 163        /*
 164         * Locate pcb for datagram.
 165         */
 166        so = solookup(&slirp->udp_last_so, &slirp->udb, &lhost, NULL);
 167
 168        if (so == NULL) {
 169          /*
 170           * If there's no socket for this packet,
 171           * create one
 172           */
 173          so = socreate(slirp);
 174          if (udp_attach(so, AF_INET) == -1) {
 175            DEBUG_MISC(" udp_attach errno = %d-%s", errno, strerror(errno));
 176            sofree(so);
 177            goto bad;
 178          }
 179
 180          /*
 181           * Setup fields
 182           */
 183          so->so_lfamily = AF_INET;
 184          so->so_laddr = ip->ip_src;
 185          so->so_lport = uh->uh_sport;
 186
 187          if ((so->so_iptos = udp_tos(so)) == 0)
 188            so->so_iptos = ip->ip_tos;
 189
 190          /*
 191           * XXXXX Here, check if it's in udpexec_list,
 192           * and if it is, do the fork_exec() etc.
 193           */
 194        }
 195
 196        so->so_ffamily = AF_INET;
 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("udp tx errno = %d-%s", errno, strerror(errno));
 212          icmp_send_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, 0,
 213                          strerror(errno));
 214          goto bad;
 215        }
 216
 217        m_free(so->so_m);   /* used for ICMP if error on sorecvfrom */
 218
 219        /* restore the orig mbuf packet */
 220        m->m_len += iphlen;
 221        m->m_data -= iphlen;
 222        *ip=save_ip;
 223        so->so_m=m;         /* ICMP backup */
 224
 225        return;
 226bad:
 227        m_free(m);
 228}
 229
 230int udp_output(struct socket *so, struct mbuf *m,
 231                struct sockaddr_in *saddr, struct sockaddr_in *daddr,
 232                int iptos)
 233{
 234        register struct udpiphdr *ui;
 235        int error = 0;
 236
 237        DEBUG_CALL("udp_output");
 238        DEBUG_ARG("so = %p", so);
 239        DEBUG_ARG("m = %p", m);
 240        DEBUG_ARG("saddr = %s", inet_ntoa(saddr->sin_addr));
 241        DEBUG_ARG("daddr = %s", inet_ntoa(daddr->sin_addr));
 242
 243        /*
 244         * Adjust for header
 245         */
 246        m->m_data -= sizeof(struct udpiphdr);
 247        m->m_len += sizeof(struct udpiphdr);
 248
 249        /*
 250         * Fill in mbuf with extended UDP header
 251         * and addresses and length put into network format.
 252         */
 253        ui = mtod(m, struct udpiphdr *);
 254    memset(&ui->ui_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr));
 255        ui->ui_x1 = 0;
 256        ui->ui_pr = IPPROTO_UDP;
 257        ui->ui_len = htons(m->m_len - sizeof(struct ip));
 258        /* XXXXX Check for from-one-location sockets, or from-any-location sockets */
 259        ui->ui_src = saddr->sin_addr;
 260        ui->ui_dst = daddr->sin_addr;
 261        ui->ui_sport = saddr->sin_port;
 262        ui->ui_dport = daddr->sin_port;
 263        ui->ui_ulen = ui->ui_len;
 264
 265        /*
 266         * Stuff checksum and output datagram.
 267         */
 268        ui->ui_sum = 0;
 269        if ((ui->ui_sum = cksum(m, m->m_len)) == 0)
 270                ui->ui_sum = 0xffff;
 271        ((struct ip *)ui)->ip_len = m->m_len;
 272
 273        ((struct ip *)ui)->ip_ttl = IPDEFTTL;
 274        ((struct ip *)ui)->ip_tos = iptos;
 275
 276        error = ip_output(so, m);
 277
 278        return (error);
 279}
 280
 281int
 282udp_attach(struct socket *so, unsigned short af)
 283{
 284  so->s = slirp_socket(af, SOCK_DGRAM, 0);
 285  if (so->s != -1) {
 286    so->so_expire = curtime + SO_EXPIRE;
 287    insque(so, &so->slirp->udb);
 288  }
 289  return(so->s);
 290}
 291
 292void
 293udp_detach(struct socket *so)
 294{
 295        so->slirp->cb->unregister_poll_fd(so->s, so->slirp->opaque);
 296        closesocket(so->s);
 297        sofree(so);
 298}
 299
 300static const struct tos_t udptos[] = {
 301        {0, 53, IPTOS_LOWDELAY, 0},                     /* DNS */
 302        {0, 0, 0, 0}
 303};
 304
 305static uint8_t
 306udp_tos(struct socket *so)
 307{
 308        int i = 0;
 309
 310        while(udptos[i].tos) {
 311                if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) ||
 312                    (udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {
 313                        so->so_emu = udptos[i].emu;
 314                        return udptos[i].tos;
 315                }
 316                i++;
 317        }
 318
 319        return 0;
 320}
 321
 322struct socket *
 323udp_listen(Slirp *slirp, uint32_t haddr, unsigned hport, uint32_t laddr,
 324           unsigned lport, int flags)
 325{
 326        /* TODO: IPv6 */
 327        struct sockaddr_in addr;
 328        struct socket *so;
 329        socklen_t addrlen = sizeof(struct sockaddr_in);
 330
 331        so = socreate(slirp);
 332        so->s = slirp_socket(AF_INET,SOCK_DGRAM,0);
 333        if (so->s < 0) {
 334            sofree(so);
 335            return NULL;
 336        }
 337        so->so_expire = curtime + SO_EXPIRE;
 338        insque(so, &slirp->udb);
 339
 340        addr.sin_family = AF_INET;
 341        addr.sin_addr.s_addr = haddr;
 342        addr.sin_port = hport;
 343
 344        if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) {
 345                udp_detach(so);
 346                return NULL;
 347        }
 348        slirp_socket_set_fast_reuse(so->s);
 349
 350        getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
 351        so->fhost.sin = addr;
 352        sotranslate_accept(so);
 353        so->so_lfamily = AF_INET;
 354        so->so_lport = lport;
 355        so->so_laddr.s_addr = laddr;
 356        if (flags != SS_FACCEPTONCE)
 357           so->so_expire = 0;
 358
 359        so->so_state &= SS_PERSISTENT_MASK;
 360        so->so_state |= SS_ISFCONNECTED | flags;
 361
 362        return so;
 363}
 364