usr/src/boot/lib/libstand/udp.c

   1 /* Taken from $NetBSD: net.c,v 1.20 1997/12/26 22:41:30 scottr Exp $    */
   2
   3 /*
   4  * Copyright (c) 1992 Regents of the University of California.
   5  * All rights reserved.
   6  *
   7  * This software was developed by the Computer Systems Engineering group
   8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
   9  * contributed to Berkeley.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  * @(#) Header: net.c,v 1.9 93/08/06 19:32:15 leres Exp  (LBL)
  36  */
  37
  38 #include <sys/cdefs.h>
  39 __FBSDID("$FreeBSD$");
  40
  41 #include <sys/param.h>
  42 #include <sys/socket.h>
  43
  44 #include <string.h>
  45
  46 #include <net/if.h>
  47 #include <netinet/in.h>
  48 #include <netinet/if_ether.h>
  49 #include <netinet/in_systm.h>
  50
  51 #include <netinet/in_pcb.h>
  52 #include <netinet/ip.h>
  53 #include <netinet/ip_var.h>
  54 #include <netinet/udp.h>
  55 #include <netinet/udp_var.h>
  56
  57 #include "stand.h"
  58 #include "net.h"
  59
  60 /* Caller must leave room for ethernet, ip and udp headers in front!! */
  61 ssize_t
  62 sendudp(d, pkt, len)
  63         struct iodesc *d;
  64         void *pkt;
  65         size_t len;
  66 {
  67         ssize_t cc;
  68         struct ip *ip;
  69         struct udphdr *uh;
  70         u_char *ea;
  71
  72 #ifdef NET_DEBUG
  73         if (debug) {
  74                 printf("sendudp: d=%lx called.\n", (long)d);
  75                 if (d) {
  76                         printf("saddr: %s:%d",
  77                             inet_ntoa(d->myip), ntohs(d->myport));
  78                         printf(" daddr: %s:%d\n",
  79                             inet_ntoa(d->destip), ntohs(d->destport));
  80                 }
  81         }
  82 #endif
  83
  84         uh = (struct udphdr *)pkt - 1;
  85         ip = (struct ip *)uh - 1;
  86         len += sizeof(*ip) + sizeof(*uh);
  87
  88         bzero(ip, sizeof(*ip) + sizeof(*uh));
  89
  90         ip->ip_v = IPVERSION;                   /* half-char */
  91         ip->ip_hl = sizeof(*ip) >> 2;           /* half-char */
  92         ip->ip_len = htons(len);
  93         ip->ip_p = IPPROTO_UDP;                 /* char */
  94         ip->ip_ttl = IPDEFTTL;                  /* char */
  95         ip->ip_src = d->myip;
  96         ip->ip_dst = d->destip;
  97         ip->ip_sum = in_cksum(ip, sizeof(*ip));  /* short, but special */
  98
  99         uh->uh_sport = d->myport;
 100         uh->uh_dport = d->destport;
 101         uh->uh_ulen = htons(len - sizeof(*ip));
 102
 103 #ifndef UDP_NO_CKSUM
 104         {
 105                 struct udpiphdr *ui;
 106                 struct ip tip;
 107
 108                 /* Calculate checksum (must save and restore ip header) */
 109                 tip = *ip;
 110                 ui = (struct udpiphdr *)ip;
 111                 bzero(&ui->ui_x1, sizeof(ui->ui_x1));
 112                 ui->ui_len = uh->uh_ulen;
 113                 uh->uh_sum = in_cksum(ui, len);
 114                 *ip = tip;
 115         }
 116 #endif
 117
 118         if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
 119             netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
 120                 ea = arpwhohas(d, ip->ip_dst);
 121         else
 122                 ea = arpwhohas(d, gateip);
 123
 124         cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
 125         if (cc == -1)
 126                 return (-1);
 127         if (cc != len)
 128                 panic("sendudp: bad write (%zd != %zd)", cc, len);
 129         return (cc - (sizeof(*ip) + sizeof(*uh)));
 130 }
 131
 132 /*
 133  * Receive a UDP packet and validate it is for us.
 134  * Caller leaves room for the headers (Ether, IP, UDP)
 135  */
 136 ssize_t
 137 readudp(d, pkt, len, tleft)
 138         struct iodesc *d;
 139         void *pkt;
 140         size_t len;
 141         time_t tleft;
 142 {
 143         ssize_t n;
 144         size_t hlen;
 145         struct ip *ip;
 146         struct udphdr *uh;
 147         u_int16_t etype;        /* host order */
 148
 149 #ifdef NET_DEBUG
 150         if (debug)
 151                 printf("readudp: called\n");
 152 #endif
 153
 154         uh = (struct udphdr *)pkt - 1;
 155         ip = (struct ip *)uh - 1;
 156
 157         n = readether(d, ip, len + sizeof(*ip) + sizeof(*uh), tleft, &etype);
 158         if (n == -1 || n < sizeof(*ip) + sizeof(*uh))
 159                 return -1;
 160
 161         /* Ethernet address checks now in readether() */
 162
 163         /* Need to respond to ARP requests. */
 164         if (etype == ETHERTYPE_ARP) {
 165                 struct arphdr *ah = (void *)ip;
 166                 if (ah->ar_op == htons(ARPOP_REQUEST)) {
 167                         /* Send ARP reply */
 168                         arp_reply(d, ah);
 169                 }
 170                 return -1;
 171         }
 172
 173         if (etype != ETHERTYPE_IP) {
 174 #ifdef NET_DEBUG
 175                 if (debug)
 176                         printf("readudp: not IP. ether_type=%x\n", etype);
 177 #endif
 178                 return -1;
 179         }
 180
 181         /* Check ip header */
 182         if (ip->ip_v != IPVERSION ||
 183             ip->ip_p != IPPROTO_UDP) {  /* half char */
 184 #ifdef NET_DEBUG
 185                 if (debug)
 186                         printf("readudp: IP version or not UDP. ip_v=%d ip_p=%d\n", ip->ip_v, ip->ip_p);
 187 #endif
 188                 return -1;
 189         }
 190
 191         hlen = ip->ip_hl << 2;
 192         if (hlen < sizeof(*ip) ||
 193             in_cksum(ip, hlen) != 0) {
 194 #ifdef NET_DEBUG
 195                 if (debug)
 196                         printf("readudp: short hdr or bad cksum.\n");
 197 #endif
 198                 return -1;
 199         }
 200         if (n < ntohs(ip->ip_len)) {
 201 #ifdef NET_DEBUG
 202                 if (debug)
 203                         printf("readudp: bad length %d < %d.\n",
 204                                (int)n, ntohs(ip->ip_len));
 205 #endif
 206                 return -1;
 207         }
 208         if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
 209 #ifdef NET_DEBUG
 210                 if (debug) {
 211                         printf("readudp: bad saddr %s != ", inet_ntoa(d->myip));
 212                         printf("%s\n", inet_ntoa(ip->ip_dst));
 213                 }
 214 #endif
 215                 return -1;
 216         }
 217
 218         /* If there were ip options, make them go away */
 219         if (hlen != sizeof(*ip)) {
 220                 bcopy(((u_char *)ip) + hlen, uh, len - hlen);
 221                 ip->ip_len = htons(sizeof(*ip));
 222                 n -= hlen - sizeof(*ip);
 223         }
 224         if (uh->uh_dport != d->myport) {
 225 #ifdef NET_DEBUG
 226                 if (debug)
 227                         printf("readudp: bad dport %d != %d\n",
 228                                 d->myport, ntohs(uh->uh_dport));
 229 #endif
 230                 return -1;
 231         }
 232
 233 #ifndef UDP_NO_CKSUM
 234         if (uh->uh_sum) {
 235                 struct udpiphdr *ui;
 236                 struct ip tip;
 237
 238                 n = ntohs(uh->uh_ulen) + sizeof(*ip);
 239                 if (n > RECV_SIZE - ETHER_SIZE) {
 240                         printf("readudp: huge packet, udp len %d\n", (int)n);
 241                         return -1;
 242                 }
 243
 244                 /* Check checksum (must save and restore ip header) */
 245                 tip = *ip;
 246                 ui = (struct udpiphdr *)ip;
 247                 bzero(&ui->ui_x1, sizeof(ui->ui_x1));
 248                 ui->ui_len = uh->uh_ulen;
 249                 if (in_cksum(ui, n) != 0) {
 250 #ifdef NET_DEBUG
 251                         if (debug)
 252                                 printf("readudp: bad cksum\n");
 253 #endif
 254                         *ip = tip;
 255                         return -1;
 256                 }
 257                 *ip = tip;
 258         }
 259 #endif
 260         if (ntohs(uh->uh_ulen) < sizeof(*uh)) {
 261 #ifdef NET_DEBUG
 262                 if (debug)
 263                         printf("readudp: bad udp len %d < %d\n",
 264                                 ntohs(uh->uh_ulen), (int)sizeof(*uh));
 265 #endif
 266                 return -1;
 267         }
 268
 269         n = (n > (ntohs(uh->uh_ulen) - sizeof(*uh))) ?
 270             ntohs(uh->uh_ulen) - sizeof(*uh) : n;
 271         return (n);
 272 }