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 } 263