1 /* $NetBSD: udp.c,v 1.2 2002/04/23 09:16:09 ragge 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(d, pkt, len) 68 struct iodesc *d; 69 void *pkt; 70 size_t len; 71 { 72 ssize_t cc; 73 struct ip *ip; 74 struct udphdr *uh; 75 u_char *ea; 76 77 #ifdef NET_DEBUG 78 if (debug) { 79 printf("sendudp: d=%lx called.\n", (long)d); 80 if (d) { 81 printf("saddr: %s:%d", 82 inet_ntoa(d->myip), ntohs(d->myport)); 83 printf(" daddr: %s:%d\n", 84 inet_ntoa(d->destip), ntohs(d->destport)); 85 } 86 } 87 #endif 88 89 uh = (struct udphdr *)pkt - 1; 90 ip = (struct ip *)uh - 1; 91 len += sizeof(*ip) + sizeof(*uh); 92 93 bzero(ip, sizeof(*ip) + sizeof(*uh)); 94 95 ip->ip_v = IPVERSION; /* half-char */ 96 ip->ip_hl = sizeof(*ip) >> 2; /* half-char */ 97 ip->ip_len = htons(len); 98 ip->ip_p = IPPROTO_UDP; /* char */ 99 ip->ip_ttl = IPDEFTTL; /* char */ 100 ip->ip_src = d->myip; 101 ip->ip_dst = d->destip; 102 ip->ip_sum = in_cksum(ip, sizeof(*ip)); /* short, but special */ 103 104 uh->uh_sport = d->myport; 105 uh->uh_dport = d->destport; 106 uh->uh_ulen = htons(len - sizeof(*ip)); 107 108 #ifndef UDP_NO_CKSUM 109 { 110 struct udpiphdr *ui; 111 struct ip tip; 112 113 /* Calculate checksum (must save and restore ip header) */ 114 tip = *ip; 115 ui = (struct udpiphdr *)ip; 116 bzero(ui->ui_x1, sizeof(ui->ui_x1)); 117 ui->ui_len = uh->uh_ulen; 118 uh->uh_sum = in_cksum(ui, len); 119 *ip = tip; 120 } 121 #endif 122 123 if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 || 124 netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask)) 125 ea = arpwhohas(d, ip->ip_dst); 126 else 127 ea = arpwhohas(d, gateip); 128 129 cc = sendether(d, ip, len, ea, ETHERTYPE_IP); 130 if (cc == -1) 131 return (-1); 132 if (cc != len) 133 panic("sendudp: bad write (%d != %d)", cc, len); 134 return (cc - (sizeof(*ip) + sizeof(*uh))); 135 } 136 137 /* 138 * Receive a UDP packet and validate it is for us. 139 * Caller leaves room for the headers (Ether, IP, UDP) 140 */ 141 ssize_t 142 readudp(d, pkt, len, tleft) 143 struct iodesc *d; 144 void *pkt; 145 size_t len; 146 time_t tleft; 147 { 148 ssize_t n; 149 size_t hlen; 150 struct ip *ip; 151 struct udphdr *uh; 152 u_int16_t etype; /* host order */ 153 154 #ifdef NET_DEBUG 155 if (debug) 156 printf("readudp: called\n"); 157 #endif 158 159 uh = (struct udphdr *)pkt - 1; 160 ip = (struct ip *)uh - 1; 161 162 n = readether(d, ip, len + sizeof(*ip) + sizeof(*uh), tleft, &etype); 163 if (n == -1 || n < sizeof(*ip) + sizeof(*uh)) 164 return -1; 165 166 /* Ethernet address checks now in readether() */ 167 168 /* Need to respond to ARP requests. */ 169 if (etype == ETHERTYPE_ARP) { 170 struct arphdr *ah = (void *)ip; 171 if (ah->ar_op == htons(ARPOP_REQUEST)) { 172 /* Send ARP reply */ 173 arp_reply(d, ah); 174 } 175 return -1; 176 } 177 178 if (etype != ETHERTYPE_IP) { 179 #ifdef NET_DEBUG 180 if (debug) 181 printf("readudp: not IP. ether_type=%x\n", etype); 182 #endif 183 return -1; 184 } 185 186 /* Check ip header */ 187 if (ip->ip_v != IPVERSION || 188 ip->ip_p != IPPROTO_UDP) { /* half char */ 189 #ifdef NET_DEBUG 190 if (debug) 191 printf("readudp: IP version or not UDP. ip_v=%d ip_p=%d\n", ip->ip_v, ip->ip_p); 192 #endif 193 return -1; 194 } 195 196 hlen = ip->ip_hl << 2; 197 if (hlen < sizeof(*ip) || 198 in_cksum(ip, hlen) != 0) { 199 #ifdef NET_DEBUG 200 if (debug) 201 printf("readudp: short hdr or bad cksum.\n"); 202 #endif 203 return -1; 204 } 205 if (n < ntohs(ip->ip_len)) { 206 #ifdef NET_DEBUG 207 if (debug) 208 printf("readudp: bad length %d < %d.\n", 209 (int)n, ntohs(ip->ip_len)); 210 #endif 211 return -1; 212 } 213 if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) { 214 #ifdef NET_DEBUG 215 if (debug) { 216 printf("readudp: bad saddr %s != ", inet_ntoa(d->myip)); 217 printf("%s\n", inet_ntoa(ip->ip_dst)); 218 } 219 #endif 220 return -1; 221 } 222 223 /* If there were ip options, make them go away */ 224 if (hlen != sizeof(*ip)) { 225 bcopy(((u_char *)ip) + hlen, uh, len - hlen); 226 ip->ip_len = htons(sizeof(*ip)); 227 n -= hlen - sizeof(*ip); 228 } 229 if (uh->uh_dport != d->myport) { 230 #ifdef NET_DEBUG 231 if (debug) 232 printf("readudp: bad dport %d != %d\n", 233 d->myport, ntohs(uh->uh_dport)); 234 #endif 235 return -1; 236 } 237 238 #ifndef UDP_NO_CKSUM 239 if (uh->uh_sum) { 240 struct udpiphdr *ui; 241 struct ip tip; 242 243 n = ntohs(uh->uh_ulen) + sizeof(*ip); 244 if (n > RECV_SIZE - ETHER_SIZE) { 245 printf("readudp: huge packet, udp len %d\n", (int)n); 246 return -1; 247 } 248 249 /* Check checksum (must save and restore ip header) */ 250 tip = *ip; 251 ui = (struct udpiphdr *)ip; 252 bzero(ui->ui_x1, sizeof(ui->ui_x1)); 253 ui->ui_len = uh->uh_ulen; 254 if (in_cksum(ui, n) != 0) { 255 #ifdef NET_DEBUG 256 if (debug) 257 printf("readudp: bad cksum\n"); 258 #endif 259 *ip = tip; 260 return -1; 261 } 262 *ip = tip; 263 } 264 #endif 265 if (ntohs(uh->uh_ulen) < sizeof(*uh)) { 266 #ifdef NET_DEBUG 267 if (debug) 268 printf("readudp: bad udp len %d < %d\n", 269 ntohs(uh->uh_ulen), (int)sizeof(*uh)); 270 #endif 271 return -1; 272 } 273 274 n -= sizeof(*ip) + sizeof(*uh); 275 return (n); 276 } 277