trans_udp.c revision 310903 
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	const int on = 1;
107
108	if ((p->input.fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
109		syslog(LOG_ERR, "creating UDP socket: %m");
110		return (SNMP_ERR_RES_UNAVAIL);
111	}
112	ip = (p->addr[0] << 24) | (p->addr[1] << 16) | (p->addr[2] << 8) |
113	    p->addr[3];
114	memset(&addr, 0, sizeof(addr));
115	addr.sin_addr.s_addr = htonl(ip);
116	addr.sin_port = htons(p->port);
117	addr.sin_family = AF_INET;
118	addr.sin_len = sizeof(addr);
119	if (addr.sin_addr.s_addr == INADDR_ANY &&
120	    setsockopt(p->input.fd, IPPROTO_IP, IP_RECVDSTADDR, &on,
121	    sizeof(on)) == -1) {
122		syslog(LOG_ERR, "setsockopt(IP_RECVDSTADDR): %m");
123		close(p->input.fd);
124		p->input.fd = -1;
125		return (SNMP_ERR_GENERR);
126	}
127	if (bind(p->input.fd, (struct sockaddr *)&addr, sizeof(addr))) {
128		if (errno == EADDRNOTAVAIL) {
129			close(p->input.fd);
130			p->input.fd = -1;
131			return (SNMP_ERR_INCONS_NAME);
132		}
133		syslog(LOG_ERR, "bind: %s:%u %m", inet_ntoa(addr.sin_addr),
134		    p->port);
135		close(p->input.fd);
136		p->input.fd = -1;
137		return (SNMP_ERR_GENERR);
138	}
139	if ((p->input.id = fd_select(p->input.fd, udp_input,
140	    p, NULL)) == NULL) {
141		close(p->input.fd);
142		p->input.fd = -1;
143		return (SNMP_ERR_GENERR);
144	}
145	return (SNMP_ERR_NOERROR);
146}
147
148/*
149 * Create a new SNMP Port object and start it, if we are not
150 * in initialization mode. The arguments are in host byte order.
151 */
152static int
153udp_open_port(u_int8_t *addr, u_int32_t udp_port, struct udp_port **pp)
154{
155	struct udp_port *port;
156	int err;
157
158	if (udp_port > 0xffff)
159		return (SNMP_ERR_NO_CREATION);
160	if ((port = malloc(sizeof(*port))) == NULL)
161		return (SNMP_ERR_GENERR);
162	memset(port, 0, sizeof(*port));
163
164	/* initialize common part */
165	port->tport.index.len = 5;
166	port->tport.index.subs[0] = addr[0];
167	port->tport.index.subs[1] = addr[1];
168	port->tport.index.subs[2] = addr[2];
169	port->tport.index.subs[3] = addr[3];
170	port->tport.index.subs[4] = udp_port;
171
172	port->addr[0] = addr[0];
173	port->addr[1] = addr[1];
174	port->addr[2] = addr[2];
175	port->addr[3] = addr[3];
176	port->port = udp_port;
177
178	port->input.fd = -1;
179	port->input.id = NULL;
180	port->input.stream = 0;
181	port->input.cred = 0;
182	port->input.peer = (struct sockaddr *)&port->ret;
183	port->input.peerlen = sizeof(port->ret);
184
185	trans_insert_port(my_trans, &port->tport);
186
187	if (community != COMM_INITIALIZE &&
188	    (err = udp_init_port(&port->tport)) != SNMP_ERR_NOERROR) {
189		udp_close_port(&port->tport);
190		return (err);
191	}
192	*pp = port;
193	return (SNMP_ERR_NOERROR);
194}
195
196/*
197 * Close an SNMP port
198 */
199static void
200udp_close_port(struct tport *tp)
201{
202	struct udp_port *port = (struct udp_port *)tp;
203
204	snmpd_input_close(&port->input);
205	trans_remove_port(tp);
206	free(port);
207}
208
209/*
210 * Send something
211 */
212static ssize_t
213udp_send(struct tport *tp, const u_char *buf, size_t len,
214    const struct sockaddr *addr, size_t addrlen)
215{
216	struct udp_port *p = (struct udp_port *)tp;
217
218	return (sendto(p->input.fd, buf, len, 0, addr, addrlen));
219}
220
221/*
222 * Port table
223 */
224int
225op_snmp_port(struct snmp_context *ctx, struct snmp_value *value,
226    u_int sub, u_int iidx, enum snmp_op op)
227{
228	asn_subid_t which = value->var.subs[sub-1];
229	struct udp_port *p;
230	u_int8_t addr[4];
231	u_int32_t port;
232
233	switch (op) {
234
235	  case SNMP_OP_GETNEXT:
236		if ((p = (struct udp_port *)trans_next_port(my_trans,
237		    &value->var, sub)) == NULL)
238			return (SNMP_ERR_NOSUCHNAME);
239		index_append(&value->var, sub, &p->tport.index);
240		break;
241
242	  case SNMP_OP_GET:
243		if ((p = (struct udp_port *)trans_find_port(my_trans,
244		    &value->var, sub)) == NULL)
245			return (SNMP_ERR_NOSUCHNAME);
246		break;
247
248	  case SNMP_OP_SET:
249		p = (struct udp_port *)trans_find_port(my_trans,
250		    &value->var, sub);
251		ctx->scratch->int1 = (p != NULL);
252
253		if (which != LEAF_begemotSnmpdPortStatus)
254			abort();
255		if (!TRUTH_OK(value->v.integer))
256			return (SNMP_ERR_WRONG_VALUE);
257
258		ctx->scratch->int2 = TRUTH_GET(value->v.integer);
259
260		if (ctx->scratch->int2) {
261			/* open an SNMP port */
262			if (p != NULL)
263				/* already open - do nothing */
264				return (SNMP_ERR_NOERROR);
265
266			if (index_decode(&value->var, sub, iidx, addr, &port))
267				return (SNMP_ERR_NO_CREATION);
268			return (udp_open_port(addr, port, &p));
269
270		} else {
271			/* close SNMP port - do in commit */
272		}
273		return (SNMP_ERR_NOERROR);
274
275	  case SNMP_OP_ROLLBACK:
276		p = (struct udp_port *)trans_find_port(my_trans,
277		    &value->var, sub);
278		if (ctx->scratch->int1 == 0) {
279			/* did not exist */
280			if (ctx->scratch->int2 == 1) {
281				/* created */
282				if (p != NULL)
283					udp_close_port(&p->tport);
284			}
285		}
286		return (SNMP_ERR_NOERROR);
287
288	  case SNMP_OP_COMMIT:
289		p = (struct udp_port *)trans_find_port(my_trans,
290		    &value->var, sub);
291		if (ctx->scratch->int1 == 1) {
292			/* did exist */
293			if (ctx->scratch->int2 == 0) {
294				/* delete */
295				if (p != NULL)
296					udp_close_port(&p->tport);
297			}
298		}
299		return (SNMP_ERR_NOERROR);
300
301	  default:
302		abort();
303	}
304
305	/*
306	 * Come here to fetch the value
307	 */
308	switch (which) {
309
310	  case LEAF_begemotSnmpdPortStatus:
311		value->v.integer = 1;
312		break;
313
314	  default:
315		abort();
316	}
317
318	return (SNMP_ERR_NOERROR);
319}
320