sys/lib/libsa/udp.c

   1 /*      $NetBSD: udp.c,v 1.7 2008/03/25 21:23:51 christos 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  * 3. All advertising materials mentioning features or use of this software
  20  *    must display the following acknowledgement:
  21  *      This product includes software developed by the University of
  22  *      California, Lawrence Berkeley Laboratory and its contributors.
  23  * 4. Neither the name of the University nor the names of its contributors
  24  *    may be used to endorse or promote products derived from this software
  25  *    without specific prior written permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  37  * SUCH DAMAGE.
  38  *
  39  * @(#) Header: net.c,v 1.9 93/08/06 19:32:15 leres Exp  (LBL)
  40  */
  41
  42 #include <sys/param.h>
  43 #include <sys/socket.h>
  44
  45 #ifdef _STANDALONE
  46 #include <lib/libkern/libkern.h>
  47 #else
  48 #include <string.h>
  49 #endif
  50
  51 #include <net/if.h>
  52 #include <net/if_ether.h>
  53
  54 #include <netinet/in.h>
  55 #include <netinet/in_systm.h>
  56 #include <netinet/ip.h>
  57 #include <netinet/ip_var.h>
  58 #include <netinet/udp.h>
  59 #include <netinet/udp_var.h>
  60
  61 #include "stand.h"
  62 #include "net.h"
  63
  64
  65 /* Caller must leave room for ethernet, ip and udp headers in front!! */
  66 ssize_t
  67 sendudp(struct iodesc *d, void *pkt, size_t len)
  68 {
  69         ssize_t cc;
  70         struct ip *ip;
  71         struct udphdr *uh;
  72         u_char *ea;
  73
  74 #ifdef NET_DEBUG
  75         if (debug) {
  76                 printf("sendudp: d=%lx called.\n", (long)d);
  77                 if (d) {
  78                         printf("saddr: %s:%d",
  79                             inet_ntoa(d->myip), ntohs(d->myport));
  80                         printf(" daddr: %s:%d\n",
  81                             inet_ntoa(d->destip), ntohs(d->destport));
  82                 }
  83         }
  84 #endif
  85
  86         uh = (struct udphdr *)pkt - 1;
  87         ip = (struct ip *)uh - 1;
  88         len += sizeof(*ip) + sizeof(*uh);
  89
  90         (void)memset(ip, 0, sizeof(*ip) + sizeof(*uh));
  91
  92         ip->ip_v = IPVERSION;                   /* half-char */
  93         ip->ip_hl = sizeof(*ip) >> 2;           /* half-char */
  94         ip->ip_len = htons(len);
  95         ip->ip_p = IPPROTO_UDP;                 /* char */
  96         ip->ip_ttl = IPDEFTTL;                  /* char */
  97         ip->ip_src = d->myip;
  98         ip->ip_dst = d->destip;
  99         ip->ip_sum = ip_cksum(ip, sizeof(*ip));  /* short, but special */
 100
 101         uh->uh_sport = d->myport;
 102         uh->uh_dport = d->destport;
 103         uh->uh_ulen = htons(len - sizeof(*ip));
 104
 105 #ifndef UDP_NO_CKSUM
 106         {
 107                 struct udpiphdr *ui;
 108                 struct ip tip;
 109
 110                 /* Calculate checksum (must save and restore ip header) */
 111                 tip = *ip;
 112                 ui = (struct udpiphdr *)ip;
 113                 (void)memset(ui->ui_x1, 0, sizeof(ui->ui_x1));
 114                 ui->ui_len = uh->uh_ulen;
 115                 uh->uh_sum = ip_cksum(ui, len);
 116                 *ip = tip;
 117         }
 118 #endif
 119
 120         if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
 121             netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
 122                 ea = arpwhohas(d, ip->ip_dst);
 123         else
 124                 ea = arpwhohas(d, gateip);
 125
 126         cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
 127         if (cc == -1)
 128                 return -1;
 129         if ((size_t)cc != len)
 130                 panic("sendudp: bad write (%d != %d)", cc, len);
 131         return (cc - (sizeof(*ip) + sizeof(*uh)));
 132 }
 133
 134 /*
 135  * Receive a UDP packet and validate it is for us.
 136  * Caller leaves room for the headers (Ether, IP, UDP)
 137  */
 138 ssize_t
 139 readudp(struct iodesc *d, void *pkt, size_t len, saseconds_t tleft)
 140 {
 141         ssize_t n;
 142         size_t hlen;
 143         struct ip *ip;
 144         struct udphdr *uh;
 145         u_int16_t etype;        /* host order */
 146
 147 #ifdef NET_DEBUG
 148         if (debug)
 149                 printf("readudp: called\n");
 150 #endif
 151
 152         uh = (struct udphdr *)pkt - 1;
 153         ip = (struct ip *)uh - 1;
 154
 155         n = readether(d, ip, len + sizeof(*ip) + sizeof(*uh), tleft, &etype);
 156         if (n == -1 || (size_t)n < sizeof(*ip) + sizeof(*uh))
 157                 return -1;
 158
 159         /* Ethernet address checks now in readether() */
 160
 161         /* Need to respond to ARP requests. */
 162         if (etype == ETHERTYPE_ARP) {
 163                 struct arphdr *ah = (void *)ip;
 164                 if (ah->ar_op == htons(ARPOP_REQUEST)) {
 165                         /* Send ARP reply */
 166                         arp_reply(d, ah);
 167                 }
 168                 return -1;
 169         }
 170
 171         if (etype != ETHERTYPE_IP) {
 172 #ifdef NET_DEBUG
 173                 if (debug)
 174                         printf("readudp: not IP. ether_type=%x\n", etype);
 175 #endif
 176                 return -1;
 177         }
 178
 179         /* Check ip header */
 180         if (ip->ip_v != IPVERSION ||
 181             ip->ip_p != IPPROTO_UDP) {  /* half char */
 182 #ifdef NET_DEBUG
 183                 if (debug) {
 184                         printf("readudp: IP version or not UDP. "
 185                                "ip_v=%d ip_p=%d\n", ip->ip_v, ip->ip_p);
 186                 }
 187 #endif
 188                 return -1;
 189         }
 190
 191         hlen = ip->ip_hl << 2;
 192         if (hlen < sizeof(*ip) || ip_cksum(ip, hlen) != 0) {
 193 #ifdef NET_DEBUG
 194                 if (debug)
 195                         printf("readudp: short hdr or bad cksum.\n");
 196 #endif
 197                 return -1;
 198         }
 199         if (n < ntohs(ip->ip_len)) {
 200 #ifdef NET_DEBUG
 201                 if (debug)
 202                         printf("readudp: bad length %d < %d.\n",
 203                                (int)n, ntohs(ip->ip_len));
 204 #endif
 205                 return -1;
 206         }
 207         if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
 208 #ifdef NET_DEBUG
 209                 if (debug) {
 210                         printf("readudp: bad saddr %s != ", inet_ntoa(d->myip));
 211                         printf("%s\n", inet_ntoa(ip->ip_dst));
 212                 }
 213 #endif
 214                 return -1;
 215         }
 216
 217         /* If there were ip options, make them go away */
 218         if (hlen != sizeof(*ip)) {
 219                 (void)memcpy(uh, ((u_char *)ip) + hlen, len - hlen);
 220                 ip->ip_len = htons(sizeof(*ip));
 221                 n -= hlen - sizeof(*ip);
 222         }
 223         if (uh->uh_dport != d->myport) {
 224 #ifdef NET_DEBUG
 225                 if (debug)
 226                         printf("readudp: bad dport %d != %d\n",
 227                                 d->myport, ntohs(uh->uh_dport));
 228 #endif
 229                 return -1;
 230         }
 231
 232 #ifndef UDP_NO_CKSUM
 233         if (uh->uh_sum) {
 234                 struct udpiphdr *ui;
 235                 struct ip tip;
 236
 237                 n = ntohs(uh->uh_ulen) + sizeof(*ip);
 238                 if (n > RECV_SIZE - ETHER_SIZE) {
 239                         printf("readudp: huge packet, udp len %d\n", (int)n);
 240                         return -1;
 241                 }
 242
 243                 /* Check checksum (must save and restore ip header) */
 244                 tip = *ip;
 245                 ui = (struct udpiphdr *)ip;
 246                 (void)memset(ui->ui_x1, 0, sizeof(ui->ui_x1));
 247                 ui->ui_len = uh->uh_ulen;
 248                 if (ip_cksum(ui, n) != 0) {
 249 #ifdef NET_DEBUG
 250                         if (debug)
 251                                 printf("readudp: bad cksum\n");
 252 #endif
 253                         *ip = tip;
 254                         return -1;
 255                 }
 256                 *ip = tip;
 257         }
 258 #endif
 259         if (ntohs(uh->uh_ulen) < sizeof(*uh)) {
 260 #ifdef NET_DEBUG
 261                 if (debug)
 262                         printf("readudp: bad udp len %d < %d\n",
 263                                 ntohs(uh->uh_ulen), (int)sizeof(*uh));
 264 #endif
 265                 return -1;
 266         }
 267
 268         n -= sizeof(*ip) + sizeof(*uh);
 269         return n;
 270 }