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: stable/11/stand/libsa/udp.c 346477 2019-04-21 03:43:27Z kevans $");
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!! */
60ssize_t
61sendudp(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 */
109ssize_t
110readudp(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