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  * 3. 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  * $FreeBSD: src/lib/libstand/udp.c,v 1.1.2.1 2000/04/15 03:09:29 ps Exp $
  37  * $DragonFly: src/lib/libstand/udp.c,v 1.4 2005/12/11 02:27:26 swildner Exp $
  38  */
  39
  40 #include <sys/param.h>
  41 #include <sys/socket.h>
  42
  43 #include <string.h>
  44
  45 #include <net/if.h>
  46 #include <netinet/in.h>
  47 #include <netinet/if_ether.h>
  48 #include <netinet/in_systm.h>
  49
  50 #include <netinet/ip.h>
  51 #include <netinet/ip_var.h>
  52 #include <netinet/udp.h>
  53 #include <netinet/udp_var.h>
  54
  55 #include "stand.h"
  56 #include "net.h"
  57
  58 /* Caller must leave room for ethernet, ip and udp headers in front!! */
  59 ssize_t
  60 sendudp(struct iodesc *d, void *pkt, size_t len)
  61 {
  62         ssize_t cc;
  63         struct ip *ip;
  64         struct udphdr *uh;
  65         u_char *ea;
  66
  67 #ifdef NET_DEBUG
  68         if (debug) {
  69                 printf("sendudp: d=%lx called.\n", (long)d);
  70                 if (d) {
  71                         printf("saddr: %s:%d",
  72                             inet_ntoa(d->myip), ntohs(d->myport));
  73                         printf(" daddr: %s:%d\n",
  74                             inet_ntoa(d->destip), ntohs(d->destport));
  75                 }
  76         }
  77 #endif
  78
  79         uh = (struct udphdr *)pkt - 1;
  80         ip = (struct ip *)uh - 1;
  81         len += sizeof(*ip) + sizeof(*uh);
  82
  83         bzero(ip, sizeof(*ip) + sizeof(*uh));
  84
  85         ip->ip_v = IPVERSION;                   /* half-char */
  86         ip->ip_hl = sizeof(*ip) >> 2;           /* half-char */
  87         ip->ip_len = htons(len);
  88         ip->ip_p = IPPROTO_UDP;                 /* char */
  89         ip->ip_ttl = IP_TTL;                    /* char */
  90         ip->ip_src = d->myip;
  91         ip->ip_dst = d->destip;
  92         ip->ip_sum = in_cksum(ip, sizeof(*ip));  /* short, but special */
  93
  94         uh->uh_sport = d->myport;
  95         uh->uh_dport = d->destport;
  96         uh->uh_ulen = htons(len - sizeof(*ip));
  97
  98 #ifndef UDP_NO_CKSUM
  99         {
 100                 struct udpiphdr *ui;
 101                 struct ip tip;
 102
 103                 /* Calculate checksum (must save and restore ip header) */
 104                 tip = *ip;
 105                 ui = (struct udpiphdr *)ip;
 106                 bzero(&ui->ui_x1, sizeof(ui->ui_x1));
 107                 ui->ui_len = uh->uh_ulen;
 108                 uh->uh_sum = in_cksum(ui, len);
 109                 *ip = tip;
 110         }
 111 #endif
 112
 113         if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
 114             netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
 115                 ea = arpwhohas(d, ip->ip_dst);
 116         else
 117                 ea = arpwhohas(d, gateip);
 118
 119         cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
 120         if (cc == -1)
 121                 return (-1);
 122         if (cc != len)
 123                 panic("sendudp: bad write (%zd != %zu)", cc, len);
 124         return (cc - (sizeof(*ip) + sizeof(*uh)));
 125 }
 126
 127 /*
 128  * Receive a UDP packet and validate it is for us.
 129  * Caller leaves room for the headers (Ether, IP, UDP)
 130  */
 131 ssize_t
 132 readudp(struct iodesc *d, void *pkt, size_t len, time_t tleft)
 133 {
 134         ssize_t n;
 135         size_t hlen;
 136         struct ip *ip;
 137         struct udphdr *uh;
 138         u_int16_t etype;        /* host order */
 139
 140 #ifdef NET_DEBUG
 141         if (debug)
 142                 printf("readudp: called\n");
 143 #endif
 144
 145         uh = (struct udphdr *)pkt - 1;
 146         ip = (struct ip *)uh - 1;
 147
 148         n = readether(d, ip, len + sizeof(*ip) + sizeof(*uh), tleft, &etype);
 149         if (n == -1 || n < sizeof(*ip) + sizeof(*uh))
 150                 return -1;
 151
 152         /* Ethernet address checks now in readether() */
 153
 154         /* Need to respond to ARP requests. */
 155         if (etype == ETHERTYPE_ARP) {
 156                 struct arphdr *ah = (void *)ip;
 157                 if (ah->ar_op == htons(ARPOP_REQUEST)) {
 158                         /* Send ARP reply */
 159                         arp_reply(d, ah);
 160                 }
 161                 return -1;
 162         }
 163
 164         if (etype != ETHERTYPE_IP) {
 165 #ifdef NET_DEBUG
 166                 if (debug)
 167                         printf("readudp: not IP. ether_type=%x\n", etype);
 168 #endif
 169                 return -1;
 170         }
 171
 172         /* Check ip header */
 173         if (ip->ip_v != IPVERSION ||
 174             ip->ip_p != IPPROTO_UDP) {  /* half char */
 175 #ifdef NET_DEBUG
 176                 if (debug)
 177                         printf("readudp: IP version or not UDP. ip_v=%d ip_p=%d\n", ip->ip_v, ip->ip_p);
 178 #endif
 179                 return -1;
 180         }
 181
 182         hlen = ip->ip_hl << 2;
 183         if (hlen < sizeof(*ip) ||
 184             in_cksum(ip, hlen) != 0) {
 185 #ifdef NET_DEBUG
 186                 if (debug)
 187                         printf("readudp: short hdr or bad cksum.\n");
 188 #endif
 189                 return -1;
 190         }
 191         if (n < ntohs(ip->ip_len)) {
 192 #ifdef NET_DEBUG
 193                 if (debug)
 194                         printf("readudp: bad length %d < %d.\n",
 195                                (int)n, ntohs(ip->ip_len));
 196 #endif
 197                 return -1;
 198         }
 199         if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
 200 #ifdef NET_DEBUG
 201                 if (debug) {
 202                         printf("readudp: bad saddr %s != ", inet_ntoa(d->myip));
 203                         printf("%s\n", inet_ntoa(ip->ip_dst));
 204                 }
 205 #endif
 206                 return -1;
 207         }
 208
 209         /* If there were ip options, make them go away */
 210         if (hlen != sizeof(*ip)) {
 211                 bcopy(((u_char *)ip) + hlen, uh, len - hlen);
 212                 ip->ip_len = htons(sizeof(*ip));
 213                 n -= hlen - sizeof(*ip);
 214         }
 215         if (uh->uh_dport != d->myport) {
 216 #ifdef NET_DEBUG
 217                 if (debug)
 218                         printf("readudp: bad dport %d != %d\n",
 219                                 d->myport, ntohs(uh->uh_dport));
 220 #endif
 221                 return -1;
 222         }
 223
 224 #ifndef UDP_NO_CKSUM
 225         if (uh->uh_sum) {
 226                 struct udpiphdr *ui;
 227                 struct ip tip;
 228
 229                 n = ntohs(uh->uh_ulen) + sizeof(*ip);
 230                 if (n > RECV_SIZE - ETHER_SIZE) {
 231                         printf("readudp: huge packet, udp len %d\n", (int)n);
 232                         return -1;
 233                 }
 234
 235                 /* Check checksum (must save and restore ip header) */
 236                 tip = *ip;
 237                 ui = (struct udpiphdr *)ip;
 238                 bzero(&ui->ui_x1, sizeof(ui->ui_x1));
 239                 ui->ui_len = uh->uh_ulen;
 240                 if (in_cksum(ui, n) != 0) {
 241 #ifdef NET_DEBUG
 242                         if (debug)
 243                                 printf("readudp: bad cksum\n");
 244 #endif
 245                         *ip = tip;
 246                         return -1;
 247                 }
 248                 *ip = tip;
 249         }
 250 #endif
 251         if (ntohs(uh->uh_ulen) < sizeof(*uh)) {
 252 #ifdef NET_DEBUG
 253                 if (debug)
 254                         printf("readudp: bad udp len %d < %d\n",
 255                                 ntohs(uh->uh_ulen), (int)sizeof(*uh));
 256 #endif
 257                 return -1;
 258         }
 259
 260         n -= sizeof(*ip) + sizeof(*uh);
 261         return (n);
 262 }