1 /* $OpenBSD: netudp.c,v 1.4 2018/03/31 17:09:56 patrick Exp $ */ 2 /* $NetBSD: net.c,v 1.14 1996/10/13 02:29:02 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1992 Regents of the University of California. 6 * All rights reserved. 7 * 8 * This software was developed by the Computer Systems Engineering group 9 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 10 * contributed to Berkeley. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Lawrence Berkeley Laboratory and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#) Header: net.c,v 1.9 93/08/06 19:32:15 leres Exp (LBL) 41 */ 42 43 #include <sys/param.h> 44 #include <sys/socket.h> 45 46 #include <net/if.h> 47 #include <netinet/in.h> 48 49 #include <netinet/if_ether.h> 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 udpiphdr *ui; 65 struct udphdr *uh; 66 u_char *ea; 67 struct ip tip; 68 69 #ifdef NET_DEBUG 70 if (debug) { 71 printf("sendudp: d=%x called.\n", (u_int)d); 72 if (d) { 73 printf("saddr: %s:%d", 74 inet_ntoa(d->myip), ntohs(d->myport)); 75 printf(" daddr: %s:%d\n", 76 inet_ntoa(d->destip), ntohs(d->destport)); 77 } 78 } 79 #endif 80 81 uh = (struct udphdr *)pkt - 1; 82 ip = (struct ip *)uh - 1; 83 len += sizeof(*ip) + sizeof(*uh); 84 85 bzero(ip, sizeof(*ip) + sizeof(*uh)); 86 87 ip->ip_v = IPVERSION; /* half-char */ 88 ip->ip_hl = sizeof(*ip) >> 2; /* half-char */ 89 ip->ip_len = htons(len); 90 ip->ip_p = IPPROTO_UDP; /* char */ 91 ip->ip_ttl = IP_TTL; /* char */ 92 ip->ip_src = d->myip; 93 ip->ip_dst = d->destip; 94 ip->ip_sum = in_cksum(ip, sizeof(*ip)); /* short, but special */ 95 96 uh->uh_sport = d->myport; 97 uh->uh_dport = d->destport; 98 uh->uh_ulen = htons(len - sizeof(*ip)); 99 100 /* Calculate checksum (must save and restore ip header) */ 101 tip = *ip; 102 ui = (struct udpiphdr *)ip; 103 bzero(ui->ui_x1, sizeof(ui->ui_x1)); 104 ui->ui_len = uh->uh_ulen; 105 uh->uh_sum = in_cksum(ui, len); 106 *ip = tip; 107 108 if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 || 109 netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask)) 110 ea = arpwhohas(d, ip->ip_dst); 111 else 112 ea = arpwhohas(d, gateip); 113 114 cc = sendether(d, ip, len, ea, ETHERTYPE_IP); 115 if (cc < 0) 116 return (-1); 117 if ((size_t)cc != len) 118 panic("sendudp: bad write (%d != %d)", cc, len); 119 return (cc - (sizeof(*ip) + sizeof(*uh))); 120 } 121 122 /* 123 * Receive a UDP packet and validate it is for us. 124 * Caller leaves room for the headers (Ether, IP, UDP) 125 */ 126 ssize_t 127 readudp(struct iodesc *d, void *pkt, size_t len, time_t tleft) 128 { 129 ssize_t n; 130 size_t hlen; 131 struct ip *ip; 132 struct udphdr *uh; 133 struct udpiphdr *ui; 134 struct ip tip; 135 u_int16_t etype; /* host order */ 136 137 #ifdef NET_DEBUG 138 if (debug) 139 printf("readudp: called\n"); 140 #endif 141 142 uh = (struct udphdr *)pkt - 1; 143 ip = (struct ip *)uh - 1; 144 145 n = readether(d, ip, len + sizeof(*ip) + sizeof(*uh), tleft, &etype); 146 if (n < 0 || (size_t)n < sizeof(*ip) + sizeof(*uh)) 147 return -1; 148 149 /* Ethernet address checks now in readether() */ 150 151 /* Need to respond to ARP requests. */ 152 if (etype == ETHERTYPE_ARP) { 153 struct arphdr *ah = (void *)ip; 154 if (ah->ar_op == htons(ARPOP_REQUEST)) { 155 /* Send ARP reply */ 156 arp_reply(d, ah); 157 } 158 return -1; 159 } 160 161 if (etype != ETHERTYPE_IP) { 162 #ifdef NET_DEBUG 163 if (debug) 164 printf("readudp: not IP. ether_type=%x\n", etype); 165 #endif 166 return -1; 167 } 168 169 /* Check ip header */ 170 if (ip->ip_v != IPVERSION || ip->ip_p != IPPROTO_UDP) { /* half char */ 171 #ifdef NET_DEBUG 172 if (debug) 173 printf("readudp: IP version or not UDP. ip_v=%d ip_p=%d\n", ip->ip_v, ip->ip_p); 174 #endif 175 return -1; 176 } 177 178 hlen = ip->ip_hl << 2; 179 if (hlen < sizeof(*ip) || in_cksum(ip, hlen) != 0) { 180 #ifdef NET_DEBUG 181 if (debug) 182 printf("readudp: short hdr or bad cksum.\n"); 183 #endif 184 return -1; 185 } 186 if (n < ntohs(ip->ip_len)) { 187 #ifdef NET_DEBUG 188 if (debug) 189 printf("readudp: bad length %d < %d.\n", 190 n, ntohs(ip->ip_len)); 191 #endif 192 return -1; 193 } 194 if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) { 195 #ifdef NET_DEBUG 196 if (debug) { 197 printf("readudp: bad saddr %s != ", inet_ntoa(d->myip)); 198 printf("%s\n", inet_ntoa(ip->ip_dst)); 199 } 200 #endif 201 return -1; 202 } 203 204 /* If there were ip options, make them go away */ 205 if (hlen != sizeof(*ip)) { 206 bcopy(((u_char *)ip) + hlen, uh, len - hlen); 207 ip->ip_len = htons(sizeof(*ip)); 208 n -= hlen - sizeof(*ip); 209 } 210 if (uh->uh_dport != d->myport) { 211 #ifdef NET_DEBUG 212 if (debug) 213 printf("readudp: bad dport %d != %d\n", 214 d->myport, ntohs(uh->uh_dport)); 215 #endif 216 return -1; 217 } 218 219 if (uh->uh_sum) { 220 n = ntohs(uh->uh_ulen) + sizeof(*ip); 221 if (n > RECV_SIZE - ETHER_SIZE) { 222 printf("readudp: huge packet, udp len %ld\n", (long)n); 223 return -1; 224 } 225 226 /* Check checksum (must save and restore ip header) */ 227 tip = *ip; 228 ui = (struct udpiphdr *)ip; 229 bzero(ui->ui_x1, sizeof(ui->ui_x1)); 230 ui->ui_len = uh->uh_ulen; 231 if (in_cksum(ui, n) != 0) { 232 #ifdef NET_DEBUG 233 if (debug) 234 printf("readudp: bad cksum\n"); 235 #endif 236 *ip = tip; 237 return -1; 238 } 239 *ip = tip; 240 } 241 if (ntohs(uh->uh_ulen) < sizeof(*uh)) { 242 #ifdef NET_DEBUG 243 if (debug) 244 printf("readudp: bad udp len %d < %d\n", 245 ntohs(uh->uh_ulen), sizeof(*uh)); 246 #endif 247 return -1; 248 } 249 250 n -= sizeof(*ip) + sizeof(*uh); 251 return (n); 252 } 253