xref: /freebsd/stand/libsa/udp.c (revision 95ee2897e98f5d444f26ed2334cc7c439f9c16c6)
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  */
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/ip.h>
52 #include <netinet/ip_var.h>
53 #include <netinet/udp.h>
54 #include <netinet/udp_var.h>
55 
56 #include "stand.h"
57 #include "net.h"
58 
59 /* Caller must leave room for ethernet, ip and udp headers in front!! */
60 ssize_t
61 sendudp(struct iodesc *d, void *pkt, size_t len)
62 {
63 	ssize_t cc;
64 	struct udpiphdr *ui;
65 	struct udphdr *uh;
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 	ui = (struct udpiphdr *)pkt - 1;
80 	bzero(ui, sizeof(*ui));
81 
82 	uh = (struct udphdr *)pkt - 1;
83 	len += sizeof(*uh);
84 
85 	uh->uh_sport = d->myport;
86 	uh->uh_dport = d->destport;
87 	uh->uh_ulen = htons(len);
88 
89 	ui->ui_pr = IPPROTO_UDP;
90 	ui->ui_len = uh->uh_ulen;
91 	ui->ui_src = d->myip;
92 	ui->ui_dst = d->destip;
93 
94 #ifndef UDP_NO_CKSUM
95 	uh->uh_sum = in_cksum(ui, len + sizeof (struct ip));
96 #endif
97 
98 	cc = sendip(d, uh, len, IPPROTO_UDP);
99 	if (cc == -1)
100 		return (-1);
101 	if (cc != len)
102 		panic("sendudp: bad write (%zd != %zd)", cc, len);
103 	return (cc - sizeof(*uh));
104 }
105 
106 /*
107  * Receive a UDP packet and validate it is for us.
108  */
109 ssize_t
110 readudp(struct iodesc *d, void **pkt, void **payload, time_t tleft)
111 {
112 	ssize_t n;
113 	struct udphdr *uh;
114 	void *ptr;
115 
116 #ifdef NET_DEBUG
117 	if (debug)
118 		printf("readudp: called\n");
119 #endif
120 
121 	uh = NULL;
122 	ptr = NULL;
123 	n = readip(d, &ptr, (void **)&uh, tleft, IPPROTO_UDP);
124 	if (n == -1 || n < sizeof(*uh) || n != ntohs(uh->uh_ulen)) {
125 		free(ptr);
126 		return (-1);
127 	}
128 
129 	if (uh->uh_dport != d->myport) {
130 #ifdef NET_DEBUG
131 		if (debug)
132 			printf("readudp: bad dport %d != %d\n",
133 				d->myport, ntohs(uh->uh_dport));
134 #endif
135 		free(ptr);
136 		return (-1);
137 	}
138 
139 #ifndef UDP_NO_CKSUM
140 	if (uh->uh_sum) {
141 		struct udpiphdr *ui;
142 		struct ip *ip;
143 		struct ip tip;
144 
145 		n = ntohs(uh->uh_ulen) + sizeof(*ip);
146 
147 		/* Check checksum (must save and restore ip header) */
148 		ip = (struct ip *)uh - 1;
149 		tip = *ip;
150 		ui = (struct udpiphdr *)ip;
151 		bzero(&ui->ui_x1, sizeof(ui->ui_x1));
152 		ui->ui_len = uh->uh_ulen;
153 		if (in_cksum(ui, n) != 0) {
154 #ifdef NET_DEBUG
155 			if (debug)
156 				printf("readudp: bad cksum\n");
157 #endif
158 			free(ptr);
159 			return (-1);
160 		}
161 		*ip = tip;
162 	}
163 #endif
164 	if (ntohs(uh->uh_ulen) < sizeof(*uh)) {
165 #ifdef NET_DEBUG
166 		if (debug)
167 			printf("readudp: bad udp len %d < %d\n",
168 				ntohs(uh->uh_ulen), (int)sizeof(*uh));
169 #endif
170 		free(ptr);
171 		return (-1);
172 	}
173 
174 	n = (n > (ntohs(uh->uh_ulen) - sizeof(*uh))) ?
175 	    ntohs(uh->uh_ulen) - sizeof(*uh) : n;
176 	*pkt = ptr;
177 	*payload = (void *)((uintptr_t)uh + sizeof(*uh));
178 	return (n);
179 }
180