trans_udp.c revision 216294 
1/*
2 * Copyright (c) 2003
3 *	Fraunhofer Institute for Open Communication Systems (FhG Fokus).
4 *	All rights reserved.
5 *
6 * Author: Harti Brandt <harti@freebsd.org>
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $Begemot: bsnmp/snmpd/trans_udp.c,v 1.5 2005/10/04 08:46:56 brandt_h Exp $
30 *
31 * UDP transport
32 */
33#include <sys/types.h>
34#include <sys/queue.h>
35
36#include <stdlib.h>
37#include <syslog.h>
38#include <string.h>
39#include <errno.h>
40#include <unistd.h>
41
42#include <netinet/in.h>
43#include <arpa/inet.h>
44
45#include "snmpmod.h"
46#include "snmpd.h"
47#include "trans_udp.h"
48#include "tree.h"
49#include "oid.h"
50
51static int udp_start(void);
52static int udp_stop(int);
53static void udp_close_port(struct tport *);
54static int udp_init_port(struct tport *);
55static ssize_t udp_send(struct tport *, const u_char *, size_t,
56    const struct sockaddr *, size_t);
57
58/* exported */
59const struct transport_def udp_trans = {
60	"udp",
61	OIDX_begemotSnmpdTransUdp,
62	udp_start,
63	udp_stop,
64	udp_close_port,
65	udp_init_port,
66	udp_send
67};
68static struct transport *my_trans;
69
70static int
71udp_start(void)
72{
73	return (trans_register(&udp_trans, &my_trans));
74}
75
76static int
77udp_stop(int force __unused)
78{
79	if (my_trans != NULL)
80		if (trans_unregister(my_trans) != 0)
81			return (SNMP_ERR_GENERR);
82	return (SNMP_ERR_NOERROR);
83}
84
85/*
86 * A UDP port is ready
87 */
88static void
89udp_input(int fd __unused, void *udata)
90{
91	struct udp_port *p = udata;
92
93	p->input.peerlen = sizeof(p->ret);
94	snmpd_input(&p->input, &p->tport);
95}
96
97/*
98 * Create a UDP socket and bind it to the given port
99 */
100static int
101udp_init_port(struct tport *tp)
102{
103	struct udp_port *p = (struct udp_port *)tp;
104	struct sockaddr_in addr;
105	u_int32_t ip;
106
107	if ((p->input.fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
108		syslog(LOG_ERR, "creating UDP socket: %m");
109		return (SNMP_ERR_RES_UNAVAIL);
110	}
111	ip = (p->addr[0] << 24) | (p->addr[1] << 16) | (p->addr[2] << 8) |
112	    p->addr[3];
113	memset(&addr, 0, sizeof(addr));
114	addr.sin_addr.s_addr = htonl(ip);
115	addr.sin_port = htons(p->port);
116	addr.sin_family = AF_INET;
117	addr.sin_len = sizeof(addr);
118	if (bind(p->input.fd, (struct sockaddr *)&addr, sizeof(addr))) {
119		if (errno == EADDRNOTAVAIL) {
120			close(p->input.fd);
121			p->input.fd = -1;
122			return (SNMP_ERR_INCONS_NAME);
123		}
124		syslog(LOG_ERR, "bind: %s:%u %m", inet_ntoa(addr.sin_addr),
125		    p->port);
126		close(p->input.fd);
127		p->input.fd = -1;
128		return (SNMP_ERR_GENERR);
129	}
130	if ((p->input.id = fd_select(p->input.fd, udp_input,
131	    p, NULL)) == NULL) {
132		close(p->input.fd);
133		p->input.fd = -1;
134		return (SNMP_ERR_GENERR);
135	}
136	return (SNMP_ERR_NOERROR);
137}
138
139/*
140 * Create a new SNMP Port object and start it, if we are not
141 * in initialization mode. The arguments are in host byte order.
142 */
143static int
144udp_open_port(u_int8_t *addr, u_int32_t udp_port, struct udp_port **pp)
145{
146	struct udp_port *port;
147	int err;
148
149	if (udp_port > 0xffff)
150		return (SNMP_ERR_NO_CREATION);
151	if ((port = malloc(sizeof(*port))) == NULL)
152		return (SNMP_ERR_GENERR);
153	memset(port, 0, sizeof(*port));
154
155	/* initialize common part */
156	port->tport.index.len = 5;
157	port->tport.index.subs[0] = addr[0];
158	port->tport.index.subs[1] = addr[1];
159	port->tport.index.subs[2] = addr[2];
160	port->tport.index.subs[3] = addr[3];
161	port->tport.index.subs[4] = udp_port;
162
163	port->addr[0] = addr[0];
164	port->addr[1] = addr[1];
165	port->addr[2] = addr[2];
166	port->addr[3] = addr[3];
167	port->port = udp_port;
168
169	port->input.fd = -1;
170	port->input.id = NULL;
171	port->input.stream = 0;
172	port->input.cred = 0;
173	port->input.peer = (struct sockaddr *)&port->ret;
174	port->input.peerlen = sizeof(port->ret);
175
176	trans_insert_port(my_trans, &port->tport);
177
178	if (community != COMM_INITIALIZE &&
179	    (err = udp_init_port(&port->tport)) != SNMP_ERR_NOERROR) {
180		udp_close_port(&port->tport);
181		return (err);
182	}
183	*pp = port;
184	return (SNMP_ERR_NOERROR);
185}
186
187/*
188 * Close an SNMP port
189 */
190static void
191udp_close_port(struct tport *tp)
192{
193	struct udp_port *port = (struct udp_port *)tp;
194
195	snmpd_input_close(&port->input);
196	trans_remove_port(tp);
197	free(port);
198}
199
200/*
201 * Send something
202 */
203static ssize_t
204udp_send(struct tport *tp, const u_char *buf, size_t len,
205    const struct sockaddr *addr, size_t addrlen)
206{
207	struct udp_port *p = (struct udp_port *)tp;
208
209	return (sendto(p->input.fd, buf, len, 0, addr, addrlen));
210}
211
212/*
213 * Port table
214 */
215int
216op_snmp_port(struct snmp_context *ctx, struct snmp_value *value,
217    u_int sub, u_int iidx, enum snmp_op op)
218{
219	asn_subid_t which = value->var.subs[sub-1];
220	struct udp_port *p;
221	u_int8_t addr[4];
222	u_int32_t port;
223
224	switch (op) {
225
226	  case SNMP_OP_GETNEXT:
227		if ((p = (struct udp_port *)trans_next_port(my_trans,
228		    &value->var, sub)) == NULL)
229			return (SNMP_ERR_NOSUCHNAME);
230		index_append(&value->var, sub, &p->tport.index);
231		break;
232
233	  case SNMP_OP_GET:
234		if ((p = (struct udp_port *)trans_find_port(my_trans,
235		    &value->var, sub)) == NULL)
236			return (SNMP_ERR_NOSUCHNAME);
237		break;
238
239	  case SNMP_OP_SET:
240		p = (struct udp_port *)trans_find_port(my_trans,
241		    &value->var, sub);
242		ctx->scratch->int1 = (p != NULL);
243
244		if (which != LEAF_begemotSnmpdPortStatus)
245			abort();
246		if (!TRUTH_OK(value->v.integer))
247			return (SNMP_ERR_WRONG_VALUE);
248
249		ctx->scratch->int2 = TRUTH_GET(value->v.integer);
250
251		if (ctx->scratch->int2) {
252			/* open an SNMP port */
253			if (p != NULL)
254				/* already open - do nothing */
255				return (SNMP_ERR_NOERROR);
256
257			if (index_decode(&value->var, sub, iidx, addr, &port))
258				return (SNMP_ERR_NO_CREATION);
259			return (udp_open_port(addr, port, &p));
260
261		} else {
262			/* close SNMP port - do in commit */
263		}
264		return (SNMP_ERR_NOERROR);
265
266	  case SNMP_OP_ROLLBACK:
267		p = (struct udp_port *)trans_find_port(my_trans,
268		    &value->var, sub);
269		if (ctx->scratch->int1 == 0) {
270			/* did not exist */
271			if (ctx->scratch->int2 == 1) {
272				/* created */
273				if (p != NULL)
274					udp_close_port(&p->tport);
275			}
276		}
277		return (SNMP_ERR_NOERROR);
278
279	  case SNMP_OP_COMMIT:
280		p = (struct udp_port *)trans_find_port(my_trans,
281		    &value->var, sub);
282		if (ctx->scratch->int1 == 1) {
283			/* did exist */
284			if (ctx->scratch->int2 == 0) {
285				/* delete */
286				if (p != NULL)
287					udp_close_port(&p->tport);
288			}
289		}
290		return (SNMP_ERR_NOERROR);
291
292	  default:
293		abort();
294	}
295
296	/*
297	 * Come here to fetch the value
298	 */
299	switch (which) {
300
301	  case LEAF_begemotSnmpdPortStatus:
302		value->v.integer = 1;
303		break;
304
305	  default:
306		abort();
307	}
308
309	return (SNMP_ERR_NOERROR);
310}
311