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 } 273