udp.c revision 1.6
1 /* $NetBSD: udp.c,v 1.6 2007/11/24 13:20:58 isaki 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 bzero(ip, 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 bzero(ui->ui_x1, 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, time_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 bcopy(((u_char *)ip) + hlen, uh, 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 bzero(ui->ui_x1, 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 } 271
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