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GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.sbin/snmpctl/snmpclient.c	Lines:	0	201	0.0 %
Date:	2017-11-13	Branches:	0	141	0.0 %


/*	$OpenBSD: snmpclient.c,v 1.14 2017/08/10 16:03:10 rob Exp $	*/

/*
 * Copyright (c) 2013 Reyk Floeter <reyk@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/queue.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/tree.h>

#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <netdb.h>
#include <errno.h>
#include <event.h>
#include <fcntl.h>
#include <string.h>
#include <ctype.h>
#include <poll.h>
#include <err.h>
#include <pwd.h>
#include <vis.h>

#include "snmpd.h"
#include "mib.h"
#include "ber.h"
#include "parser.h"

struct snmpc {
	size_t			 sc_root_len;
	struct ber_oid		 sc_root_oid;
	struct ber_oid		 sc_last_oid;
	struct ber_oid		 sc_oid;
	struct sockaddr_storage	 sc_addr;
	socklen_t		 sc_addr_len;
	u_int32_t		 sc_msgid;
	int			 sc_fd;
	int			 sc_retry;
	int			 sc_retry_max;
	const char		*sc_community;
	int			 sc_version;
	int			 sc_nresp;
};

#define	SNMPC_RETRY_MAX		3
#define SNMPC_COMMUNITY		"public"
#define SNMPC_OID_DEFAULT	"system"
#define SNMPC_OID_ALL		"1.0"
#define SNMPC_MAXREPETITIONS	10

#define	SNMPC_DATEANDTIME_LEN		11
#define	SNMPC_DATEANDTIME_SHORT_LEN	8

void	 snmpc_run(struct snmpc *, enum actions, const char *);
void	 snmpc_request(struct snmpc *, u_long);
int	 snmpc_response(struct snmpc *);
int	 snmpc_sendreq(struct snmpc *, u_long);
int	 snmpc_recvresp(int, int, u_int32_t, struct ber_element **);

struct display_hint *
	 snmpc_display_hint_lookup(struct ber_oid *);
void	 snmpc_display_hint(struct ber_oid *, char **);
char	*snmpc_physaddress(char *);
char	*snmpc_dateandtime(char *);

struct display_hint {
	struct ber_oid		 oid;
	char			*(*print)(char *);
} display_hints[] = {
	{ { { MIB_ifPhysAddress } },		snmpc_physaddress },
	{ { { MIB_ipNetToMediaPhysAddress } },	snmpc_physaddress },
	{ { { MIB_hrSystemDate } },		snmpc_dateandtime }
};

void
snmpclient(struct parse_result *res)
{
	struct snmpc		 sc;
	struct addrinfo		 hints, *ai, *ai0;
	int			 s;
	int			 error;
	u_int			 i;
	struct passwd		*pw;
	struct parse_val	*oid;

	for (i = 0; i < sizeof(display_hints) / sizeof(display_hints[0]); i++)
		smi_oidlen(&display_hints[i].oid);

	bzero(&sc, sizeof(sc));

	/* Get client configuration */
	if (res->community == NULL)
		res->community = strdup(SNMPC_COMMUNITY);
	if (res->version == -1 || res->version > SNMP_V2)
		res->version = SNMP_V2;
	if (res->community == NULL)
		err(1, "strdup");

	/* Checks */
	if ((res->action == BULKWALK) && (res->version < SNMP_V2))
		errx(1, "invalid version for bulkwalk");

	/* Resolve target host name */
	bzero(&hints, sizeof(hints));
	hints.ai_family = PF_UNSPEC;
	hints.ai_socktype = SOCK_DGRAM;
	error = getaddrinfo(res->host, "snmp", &hints, &ai0);
	if (error)
		errx(1, "%s", gai_strerror(error));
	s = -1;
	for (ai = ai0; ai; ai = ai->ai_next) {
		if ((s = socket(ai->ai_family, ai->ai_socktype,
                    ai->ai_protocol)) == -1) {
			continue;
		}
		/* use first available address */
 		break;
	}
	if (s == -1)
		errx(1, "invalid host");

	bcopy(ai->ai_addr, &sc.sc_addr, ai->ai_addrlen);
	sc.sc_addr_len = ai->ai_addrlen;
	freeaddrinfo(ai0);

	/*
	 * Drop privileges to mitigate the risk when running as root.
	 */
	if (geteuid() == 0) {
		if ((pw = getpwnam(SNMPD_USER)) == NULL)
			err(1, "snmpctl: getpwnam");
#ifndef DEBUG
		if (chroot(pw->pw_dir) == -1)
			err(1, "snmpctl: chroot");
		if (chdir("/") == -1)
			err(1, "snmpctl: chdir(\"/\")");
		if (setgroups(1, &pw->pw_gid) ||
		    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
		    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
			err(1, "snmpctl: cannot drop privileges");
#endif
	}

	if (pledge("stdio dns flock rpath cpath wpath", NULL) == -1)
		fatal("pledge");

	sc.sc_fd = s;
	sc.sc_community = res->community;
	sc.sc_version = res->version;
	sc.sc_retry_max = SNMPC_RETRY_MAX;

	if (TAILQ_EMPTY(&res->oids)) {
			snmpc_run(&sc, res->action, SNMPC_OID_DEFAULT);
	} else {
		TAILQ_FOREACH(oid, &res->oids, val_entry) {
			snmpc_run(&sc, res->action, oid->val);
		}
	}

	close(sc.sc_fd);
}

void
snmpc_run(struct snmpc *sc, enum actions action, const char *oid)
{
	if (strcmp("all", oid) == 0)
		oid = SNMPC_OID_ALL;

	/*
	 * Set up the root OID and get the prefix length to shorten the
	 * printed OID strings of the children.
	 */
	if (smi_string2oid(oid, &sc->sc_oid) == -1)
		errx(1, "oid");

	bcopy(&sc->sc_oid, &sc->sc_root_oid, sizeof(sc->sc_root_oid));
	bcopy(&sc->sc_oid, &sc->sc_last_oid, sizeof(sc->sc_last_oid));
	if (sc->sc_oid.bo_n > 2)
		sc->sc_root_len = sc->sc_oid.bo_n - 1;

	sc->sc_nresp = 0;

	if (action == GET)
		snmpc_request(sc, SNMP_C_GETREQ);
	else if (action == BULKWALK)
		snmpc_request(sc, SNMP_C_GETBULKREQ);
	else
		snmpc_request(sc, SNMP_C_GETNEXTREQ);
}

void
snmpc_request(struct snmpc *sc, u_long type)
{
	struct pollfd		 pfd[1];
	int			 nfds, ret;

	/* Send SNMP request */
	if (snmpc_sendreq(sc, type) == -1)
		err(1, "request failed");

	/* Wait for response */
	pfd[0].fd = sc->sc_fd;
	pfd[0].events = POLLIN;
	nfds = poll(pfd, 1, 3 * 1000);
	if (nfds == -1 || (pfd[0].revents & (POLLERR|POLLHUP|POLLNVAL)))
		errx(1, "poll error");
	if (nfds == 0) {
		if (sc->sc_retry++ < sc->sc_retry_max) {
			warnx("time out, retry %d/%d",
			    sc->sc_retry, sc->sc_retry_max);
			snmpc_request(sc, type);
			return;
		}
		errx(1, "time out");
	}
	sc->sc_retry = 0;

	if ((ret = snmpc_response(sc)) != 0) {
		if (ret == -1)
			err(1, "response");
		return;
	}

	if (type == SNMP_C_GETREQ)
		return;

	snmpc_request(sc, type);
}

int
snmpc_response(struct snmpc *sc)
{
	char			 buf[BUFSIZ];
	struct ber_element	*resp = NULL, *s, *e;
	char			*value = NULL, *p;
	int			 ret = 0;

	/* Receive response */
	if (snmpc_recvresp(sc->sc_fd, sc->sc_version,
	    sc->sc_msgid, &resp) == -1)
		return (-1);

	if (ber_scanf_elements(resp, "{SS{SSSS{e}}", &s) != 0)
		goto fail;

	for (; s != NULL; s = s->be_next) {
		if (ber_scanf_elements(s, "{oe}", &sc->sc_oid, &e) != 0)
			goto fail;

		/* Break if the returned OID is not a child of the root. */
		if (sc->sc_nresp &&
		    (ber_oid_cmp(&sc->sc_root_oid, &sc->sc_oid) != 2 ||
		    e->be_class == BER_CLASS_CONTEXT ||
		    e->be_type == BER_TYPE_NULL)) {
			ret = 1;
			break;
		}

		if ((value = smi_print_element(e)) != NULL) {
			smi_oid2string(&sc->sc_oid, buf, sizeof(buf),
			    sc->sc_root_len);
			snmpc_display_hint(&sc->sc_oid, &value);
			p = buf;
			if (*p != '\0')
				printf("%s=%s\n", p, value);
			else
				printf("%s\n", value);
			free(value);
		}
		bcopy(&sc->sc_oid, &sc->sc_last_oid, sizeof(sc->sc_last_oid));
	}

	sc->sc_nresp++;

	ber_free_elements(resp);
	return (ret);

 fail:
	if (resp != NULL)
		ber_free_elements(resp);
	errno = EINVAL;
	return (-1);
}

void
snmpc_display_hint(struct ber_oid *oid, char **val)
{
	struct display_hint	*h;
	char			*newval;

	if (*val == NULL || strlen(*val) == 0)
		return;

	if ((h = snmpc_display_hint_lookup(oid)) == NULL)
		return;
	/* best-effort translation */
	if ((newval = h->print(*val)) == NULL)
		return;

	free(*val);
	*val = newval;
}

char *
snmpc_physaddress(char *v)
{
	char			 buf[ETHER_ADDR_LEN + 2];
	char			*str;
	ssize_t			 n;

	n = strnunvis(buf, v, ETHER_ADDR_LEN + 2);
	if (n == -1 || n != ETHER_ADDR_LEN + 2)
		return (NULL);
	if (asprintf(&str, "\"%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx\"",
	    buf[1], buf[2], buf[3], buf[4], buf[5], buf[6]) == -1)
		return (NULL);
	return (str);
}

char *
snmpc_dateandtime(char *v)
{
	char			 buf[SNMPC_DATEANDTIME_LEN + 2];
	u_int16_t		 year;
	char			*str;
	ssize_t			 n;

	if ((n = strnunvis(buf, v, SNMPC_DATEANDTIME_LEN + 2)) == -1)
		return (NULL);

	bcopy(&buf[1], &year, sizeof(year));
	year = ntohs(year);

	switch (n) {
	case SNMPC_DATEANDTIME_SHORT_LEN + 2:
		if (asprintf(&str,
		    "\"%hu-%.02hhu-%.02hhu %.02hhu:%.02hhu:%.02hhu\"",
		    year, buf[3], buf[4], buf[5], buf[6], buf[7]) == -1)
			return (NULL);
		break;
	case SNMPC_DATEANDTIME_LEN + 2:
		if (asprintf(&str,
		    "\"%hu-%.02hhu-%.02hhu %.02hhu:%.02hhu:%.02hhu"
		    "%c%.02hhu%.02hhu\"",
		    year, buf[3], buf[4], buf[5], buf[6],
		    buf[7], buf[9], buf[10], buf[11]) == -1)
			return (NULL);
		break;
	default:
		return (NULL);
	}

	return (str);
}

struct display_hint *
snmpc_display_hint_lookup(struct ber_oid *oid)
{
	u_int			 i, j, found;

	for (i = 0; i < sizeof(display_hints) / sizeof(display_hints[0]); i++) {
		if (oid->bo_n < display_hints[i].oid.bo_n)
			continue;
		found = 1;
		for (j = 0; j < display_hints[i].oid.bo_n; j++) {
			if (oid->bo_id[j] != display_hints[i].oid.bo_id[j]) {
				found = 0;
				break;
			}
		}

		if (found)
			return (&display_hints[i]);
	}
	return (NULL);
}

int
snmpc_sendreq(struct snmpc *sc, u_long type)
{
	struct ber_element	*root, *b;
	struct ber		 ber;
	ssize_t			 len;
	u_int8_t		*ptr;
	int			 erroridx = 0;

	if (type == SNMP_C_GETBULKREQ)
		erroridx = SNMPC_MAXREPETITIONS;

	/* SNMP header */
	sc->sc_msgid = arc4random();
	if ((root = ber_add_sequence(NULL)) == NULL)
		return (-1);
	if ((b = ber_printf_elements(root, "ds{tddd{{O0}}",
	    sc->sc_version, sc->sc_community, BER_CLASS_CONTEXT, type,
	    sc->sc_msgid, 0, erroridx, &sc->sc_oid)) == NULL) {
		errno = EINVAL;
		goto fail;
	}

#ifdef DEBUG
	fprintf(stderr, "REQUEST(%lu):\n", type);
	smi_debug_elements(root);
#endif

	bzero(&ber, sizeof(ber));
	ber.fd = -1;

	len = ber_write_elements(&ber, root);
	if (ber_get_writebuf(&ber, (void *)&ptr) < 1)
		goto berfail;

	if (sendto(sc->sc_fd, ptr, len, 0,
	    (struct sockaddr *)&sc->sc_addr, sc->sc_addr_len) == -1)
		goto berfail;

	ber_free_elements(root);
	ber_free(&ber);
	return (0);

berfail:
	ber_free(&ber);
fail:
	ber_free_elements(root);
	return (-1);
}

int
snmpc_recvresp(int s, int msgver, u_int32_t msgid,
    struct ber_element **respptr)
{
	char			 buf[READ_BUF_SIZE];
	ssize_t			 rlen;
	struct ber		 ber;
	struct ber_element	*resp = NULL;
	char			*comn;
	long long		 ver, id;

	if ((rlen = recv(s, buf, sizeof(buf), MSG_WAITALL)) == -1)
		return (-1);

	bzero(&ber, sizeof(ber));
	ber.fd = -1;
	ber_set_application(&ber, smi_application);
	ber_set_readbuf(&ber, buf, rlen);

#ifdef DEBUG
	fprintf(stderr, "RESPONSE (%ld bytes):\n", rlen);
#endif

	resp = ber_read_elements(&ber, NULL);
	if (resp == NULL)
		goto fail;

#ifdef DEBUG
	smi_debug_elements(resp);
#endif

	if (ber_scanf_elements(resp, "{is{i", &ver, &comn, &id) != 0)
		goto fail;
	if (!(msgver == (int)ver && msgid == (u_int32_t)id))
		goto fail;

	*respptr = resp;
	return (0);

 fail:
	if (resp != NULL)
		ber_free_elements(resp);
	errno = EINVAL;
	return (-1);
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: snmpclient.c,v 1.14 2017/08/10 16:03:10 rob Exp $ */
2
3			/*
4			* Copyright (c) 2013 Reyk Floeter <reyk@openbsd.org>
5			*
6			* Permission to use, copy, modify, and distribute this software for any
7			* purpose with or without fee is hereby granted, provided that the above
8			* copyright notice and this permission notice appear in all copies.
9			*
10			* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11			* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12			* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13			* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14			* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15			* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16			* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17			*/
18
19			#include <sys/queue.h>
20			#include <sys/types.h>
21			#include <sys/stat.h>
22			#include <sys/socket.h>
23			#include <sys/tree.h>
24
25			#include <net/if.h>
26			#include <netinet/in.h>
27			#include <arpa/inet.h>
28
29			#include <stdlib.h>
30			#include <stdio.h>
31			#include <unistd.h>
32			#include <netdb.h>
33			#include <errno.h>
34			#include <event.h>
35			#include <fcntl.h>
36			#include <string.h>
37			#include <ctype.h>
38			#include <poll.h>
39			#include <err.h>
40			#include <pwd.h>
41			#include <vis.h>
42
43			#include "snmpd.h"
44			#include "mib.h"
45			#include "ber.h"
46			#include "parser.h"
47
48			struct snmpc {
49			size_t sc_root_len;
50			struct ber_oid sc_root_oid;
51			struct ber_oid sc_last_oid;
52			struct ber_oid sc_oid;
53			struct sockaddr_storage sc_addr;
54			socklen_t sc_addr_len;
55			u_int32_t sc_msgid;
56			int sc_fd;
57			int sc_retry;
58			int sc_retry_max;
59			const char *sc_community;
60			int sc_version;
61			int sc_nresp;
62			};
63
64			#define SNMPC_RETRY_MAX 3
65			#define SNMPC_COMMUNITY "public"
66			#define SNMPC_OID_DEFAULT "system"
67			#define SNMPC_OID_ALL "1.0"
68			#define SNMPC_MAXREPETITIONS 10
69
70			#define SNMPC_DATEANDTIME_LEN 11
71			#define SNMPC_DATEANDTIME_SHORT_LEN 8
72
73			void snmpc_run(struct snmpc , enum actions, const char );
74			void snmpc_request(struct snmpc *, u_long);
75			int snmpc_response(struct snmpc *);
76			int snmpc_sendreq(struct snmpc *, u_long);
77			int snmpc_recvresp(int, int, u_int32_t, struct ber_element **);
78
79			struct display_hint *
80			snmpc_display_hint_lookup(struct ber_oid *);
81			void snmpc_display_hint(struct ber_oid , char *);
82			char snmpc_physaddress(char );
83			char snmpc_dateandtime(char );
84
85			struct display_hint {
86			struct ber_oid oid;
87			char (print)(char *);
88			} display_hints[] = {
89			{ { { MIB_ifPhysAddress } }, snmpc_physaddress },
90			{ { { MIB_ipNetToMediaPhysAddress } }, snmpc_physaddress },
91			{ { { MIB_hrSystemDate } }, snmpc_dateandtime }
92			};
93
94			void
95			snmpclient(struct parse_result *res)
96			{
97			struct snmpc sc;
98			struct addrinfo hints, ai, ai0;
99			int s;
100			int error;
101			u_int i;
102			struct passwd *pw;
103			struct parse_val *oid;
104
105			for (i = 0; i < sizeof(display_hints) / sizeof(display_hints[0]); i++)
106			smi_oidlen(&display_hints[i].oid);
107
108			bzero(&sc, sizeof(sc));
109
110			/* Get client configuration */
111			if (res->community == NULL)
112			res->community = strdup(SNMPC_COMMUNITY);
113			if (res->version == -1 \|\| res->version > SNMP_V2)
114			res->version = SNMP_V2;
115			if (res->community == NULL)
116			err(1, "strdup");
117
118			/* Checks */
119			if ((res->action == BULKWALK) && (res->version < SNMP_V2))
120			errx(1, "invalid version for bulkwalk");
121
122			/* Resolve target host name */
123			bzero(&hints, sizeof(hints));
124			hints.ai_family = PF_UNSPEC;
125			hints.ai_socktype = SOCK_DGRAM;
126			error = getaddrinfo(res->host, "snmp", &hints, &ai0);
127			if (error)
128			errx(1, "%s", gai_strerror(error));
129			s = -1;
130			for (ai = ai0; ai; ai = ai->ai_next) {
131			if ((s = socket(ai->ai_family, ai->ai_socktype,
132			ai->ai_protocol)) == -1) {
133			continue;
134			}
135			/* use first available address */
136			break;
137			}
138			if (s == -1)
139			errx(1, "invalid host");
140
141			bcopy(ai->ai_addr, &sc.sc_addr, ai->ai_addrlen);
142			sc.sc_addr_len = ai->ai_addrlen;
143			freeaddrinfo(ai0);
144
145			/*
146			* Drop privileges to mitigate the risk when running as root.
147			*/
148			if (geteuid() == 0) {
149			if ((pw = getpwnam(SNMPD_USER)) == NULL)
150			err(1, "snmpctl: getpwnam");
151			#ifndef DEBUG
152			if (chroot(pw->pw_dir) == -1)
153			err(1, "snmpctl: chroot");
154			if (chdir("/") == -1)
155			err(1, "snmpctl: chdir(\"/\")");
156			if (setgroups(1, &pw->pw_gid) \|\|
157			setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) \|\|
158			setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
159			err(1, "snmpctl: cannot drop privileges");
160			#endif
161			}
162
163			if (pledge("stdio dns flock rpath cpath wpath", NULL) == -1)
164			fatal("pledge");
165
166			sc.sc_fd = s;
167			sc.sc_community = res->community;
168			sc.sc_version = res->version;
169			sc.sc_retry_max = SNMPC_RETRY_MAX;
170
171			if (TAILQ_EMPTY(&res->oids)) {
172			snmpc_run(&sc, res->action, SNMPC_OID_DEFAULT);
173			} else {
174			TAILQ_FOREACH(oid, &res->oids, val_entry) {
175			snmpc_run(&sc, res->action, oid->val);
176			}
177			}
178
179			close(sc.sc_fd);
180			}
181
182			void
183			snmpc_run(struct snmpc sc, enum actions action, const char oid)
184			{
185			if (strcmp("all", oid) == 0)
186			oid = SNMPC_OID_ALL;
187
188			/*
189			* Set up the root OID and get the prefix length to shorten the
190			* printed OID strings of the children.
191			*/
192			if (smi_string2oid(oid, &sc->sc_oid) == -1)
193			errx(1, "oid");
194
195			bcopy(&sc->sc_oid, &sc->sc_root_oid, sizeof(sc->sc_root_oid));
196			bcopy(&sc->sc_oid, &sc->sc_last_oid, sizeof(sc->sc_last_oid));
197			if (sc->sc_oid.bo_n > 2)
198			sc->sc_root_len = sc->sc_oid.bo_n - 1;
199
200			sc->sc_nresp = 0;
201
202			if (action == GET)
203			snmpc_request(sc, SNMP_C_GETREQ);
204			else if (action == BULKWALK)
205			snmpc_request(sc, SNMP_C_GETBULKREQ);
206			else
207			snmpc_request(sc, SNMP_C_GETNEXTREQ);
208			}
209
210			void
211			snmpc_request(struct snmpc *sc, u_long type)
212			{
213			struct pollfd pfd[1];
214			int nfds, ret;
215
216			/* Send SNMP request */
217			if (snmpc_sendreq(sc, type) == -1)
218			err(1, "request failed");
219
220			/* Wait for response */
221			pfd[0].fd = sc->sc_fd;
222			pfd[0].events = POLLIN;
223			nfds = poll(pfd, 1, 3 * 1000);
224			if (nfds == -1 \|\| (pfd[0].revents & (POLLERR\|POLLHUP\|POLLNVAL)))
225			errx(1, "poll error");
226			if (nfds == 0) {
227			if (sc->sc_retry++ < sc->sc_retry_max) {
228			warnx("time out, retry %d/%d",
229			sc->sc_retry, sc->sc_retry_max);
230			snmpc_request(sc, type);
231			return;
232			}
233			errx(1, "time out");
234			}
235			sc->sc_retry = 0;
236
237			if ((ret = snmpc_response(sc)) != 0) {
238			if (ret == -1)
239			err(1, "response");
240			return;
241			}
242
243			if (type == SNMP_C_GETREQ)
244			return;
245
246			snmpc_request(sc, type);
247			}
248
249			int
250			snmpc_response(struct snmpc *sc)
251			{
252			char buf[BUFSIZ];
253			struct ber_element resp = NULL, s, *e;
254			char value = NULL, p;
255			int ret = 0;
256
257			/* Receive response */
258			if (snmpc_recvresp(sc->sc_fd, sc->sc_version,
259			sc->sc_msgid, &resp) == -1)
260			return (-1);
261
262			if (ber_scanf_elements(resp, "{SS{SSSS{e}}", &s) != 0)
263			goto fail;
264
265			for (; s != NULL; s = s->be_next) {
266			if (ber_scanf_elements(s, "{oe}", &sc->sc_oid, &e) != 0)
267			goto fail;
268
269			/* Break if the returned OID is not a child of the root. */
270			if (sc->sc_nresp &&
271			(ber_oid_cmp(&sc->sc_root_oid, &sc->sc_oid) != 2 \|\|
272			e->be_class == BER_CLASS_CONTEXT \|\|
273			e->be_type == BER_TYPE_NULL)) {
274			ret = 1;
275			break;
276			}
277
278			if ((value = smi_print_element(e)) != NULL) {
279			smi_oid2string(&sc->sc_oid, buf, sizeof(buf),
280			sc->sc_root_len);
281			snmpc_display_hint(&sc->sc_oid, &value);
282			p = buf;
283			if (*p != '\0')
284			printf("%s=%s\n", p, value);
285			else
286			printf("%s\n", value);
287			free(value);
288			}
289			bcopy(&sc->sc_oid, &sc->sc_last_oid, sizeof(sc->sc_last_oid));
290			}
291
292			sc->sc_nresp++;
293
294			ber_free_elements(resp);
295			return (ret);
296
297			fail:
298			if (resp != NULL)
299			ber_free_elements(resp);
300			errno = EINVAL;
301			return (-1);
302			}
303
304			void
305			snmpc_display_hint(struct ber_oid oid, char *val)
306			{
307			struct display_hint *h;
308			char *newval;
309
310			if (val == NULL \|\| strlen(val) == 0)
311			return;
312
313			if ((h = snmpc_display_hint_lookup(oid)) == NULL)
314			return;
315			/* best-effort translation */
316			if ((newval = h->print(*val)) == NULL)
317			return;
318
319			free(*val);
320			*val = newval;
321			}
322
323			char *
324			snmpc_physaddress(char *v)
325			{
326			char buf[ETHER_ADDR_LEN + 2];
327			char *str;
328			ssize_t n;
329
330			n = strnunvis(buf, v, ETHER_ADDR_LEN + 2);
331			if (n == -1 \|\| n != ETHER_ADDR_LEN + 2)
332			return (NULL);
333			if (asprintf(&str, "\"%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx\"",
334			buf[1], buf[2], buf[3], buf[4], buf[5], buf[6]) == -1)
335			return (NULL);
336			return (str);
337			}
338
339			char *
340			snmpc_dateandtime(char *v)
341			{
342			char buf[SNMPC_DATEANDTIME_LEN + 2];
343			u_int16_t year;
344			char *str;
345			ssize_t n;
346
347			if ((n = strnunvis(buf, v, SNMPC_DATEANDTIME_LEN + 2)) == -1)
348			return (NULL);
349
350			bcopy(&buf[1], &year, sizeof(year));
351			year = ntohs(year);
352
353			switch (n) {
354			case SNMPC_DATEANDTIME_SHORT_LEN + 2:
355			if (asprintf(&str,
356			"\"%hu-%.02hhu-%.02hhu %.02hhu:%.02hhu:%.02hhu\"",
357			year, buf[3], buf[4], buf[5], buf[6], buf[7]) == -1)
358			return (NULL);
359			break;
360			case SNMPC_DATEANDTIME_LEN + 2:
361			if (asprintf(&str,
362			"\"%hu-%.02hhu-%.02hhu %.02hhu:%.02hhu:%.02hhu"
363			"%c%.02hhu%.02hhu\"",
364			year, buf[3], buf[4], buf[5], buf[6],
365			buf[7], buf[9], buf[10], buf[11]) == -1)
366			return (NULL);
367			break;
368			default:
369			return (NULL);
370			}
371
372			return (str);
373			}
374
375			struct display_hint *
376			snmpc_display_hint_lookup(struct ber_oid *oid)
377			{
378			u_int i, j, found;
379
380			for (i = 0; i < sizeof(display_hints) / sizeof(display_hints[0]); i++) {
381			if (oid->bo_n < display_hints[i].oid.bo_n)
382			continue;
383			found = 1;
384			for (j = 0; j < display_hints[i].oid.bo_n; j++) {
385			if (oid->bo_id[j] != display_hints[i].oid.bo_id[j]) {
386			found = 0;
387			break;
388			}
389			}
390
391			if (found)
392			return (&display_hints[i]);
393			}
394			return (NULL);
395			}
396
397			int
398			snmpc_sendreq(struct snmpc *sc, u_long type)
399			{
400			struct ber_element root, b;
401			struct ber ber;
402			ssize_t len;
403			u_int8_t *ptr;
404			int erroridx = 0;
405
406			if (type == SNMP_C_GETBULKREQ)
407			erroridx = SNMPC_MAXREPETITIONS;
408
409			/* SNMP header */
410			sc->sc_msgid = arc4random();
411			if ((root = ber_add_sequence(NULL)) == NULL)
412			return (-1);
413			if ((b = ber_printf_elements(root, "ds{tddd{{O0}}",
414			sc->sc_version, sc->sc_community, BER_CLASS_CONTEXT, type,
415			sc->sc_msgid, 0, erroridx, &sc->sc_oid)) == NULL) {
416			errno = EINVAL;
417			goto fail;
418			}
419
420			#ifdef DEBUG
421			fprintf(stderr, "REQUEST(%lu):\n", type);
422			smi_debug_elements(root);
423			#endif
424
425			bzero(&ber, sizeof(ber));
426			ber.fd = -1;
427
428			len = ber_write_elements(&ber, root);
429			if (ber_get_writebuf(&ber, (void *)&ptr) < 1)
430			goto berfail;
431
432			if (sendto(sc->sc_fd, ptr, len, 0,
433			(struct sockaddr *)&sc->sc_addr, sc->sc_addr_len) == -1)
434			goto berfail;
435
436			ber_free_elements(root);
437			ber_free(&ber);
438			return (0);
439
440			berfail:
441			ber_free(&ber);
442			fail:
443			ber_free_elements(root);
444			return (-1);
445			}
446
447			int
448			snmpc_recvresp(int s, int msgver, u_int32_t msgid,
449			struct ber_element **respptr)
450			{
451			char buf[READ_BUF_SIZE];
452			ssize_t rlen;
453			struct ber ber;
454			struct ber_element *resp = NULL;
455			char *comn;
456			long long ver, id;
457
458			if ((rlen = recv(s, buf, sizeof(buf), MSG_WAITALL)) == -1)
459			return (-1);
460
461			bzero(&ber, sizeof(ber));
462			ber.fd = -1;
463			ber_set_application(&ber, smi_application);
464			ber_set_readbuf(&ber, buf, rlen);
465
466			#ifdef DEBUG
467			fprintf(stderr, "RESPONSE (%ld bytes):\n", rlen);
468			#endif
469
470			resp = ber_read_elements(&ber, NULL);
471			if (resp == NULL)
472			goto fail;
473
474			#ifdef DEBUG
475			smi_debug_elements(resp);
476			#endif
477
478			if (ber_scanf_elements(resp, "{is{i", &ver, &comn, &id) != 0)
479			goto fail;
480			if (!(msgver == (int)ver && msgid == (u_int32_t)id))
481			goto fail;
482
483			*respptr = resp;
484			return (0);
485
486			fail:
487			if (resp != NULL)
488			ber_free_elements(resp);
489			errno = EINVAL;
490			return (-1);
491			}