freebsd-skq/contrib/bsnmp/snmpd/trans_udp.c
Andrey V. Elsukov 04d1781439 Add IPv6 transport for bsnmp.
This patch adds a new table begemotSnmpdTransInetTable that uses the
InetAddressType textual convention and can be used to create listening
ports for IPv4, IPv6, zoned IPv6 and based on DNS names. It also supports
future extension beyond UDP by adding a protocol identifier to the table
index. In order to support this gensnmptree had to be modified.

Submitted by:   harti
MFC after:      1 month
Relnotes:       yes
Differential Revision:  https://reviews.freebsd.org/D16654
2019-04-02 12:50:01 +00:00

440 lines
10 KiB
C

/*
* Copyright (c) 2003
* Fraunhofer Institute for Open Communication Systems (FhG Fokus).
* All rights reserved.
*
* Author: Harti Brandt <harti@freebsd.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Begemot: bsnmp/snmpd/trans_udp.c,v 1.5 2005/10/04 08:46:56 brandt_h Exp $
*
* UDP transport
*/
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/ucred.h>
#include <stdbool.h>
#include <stdlib.h>
#include <syslog.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "snmpmod.h"
#include "snmpd.h"
#include "trans_udp.h"
#include "tree.h"
#include "oid.h"
static int udp_start(void);
static int udp_stop(int);
static void udp_close_port(struct tport *);
static int udp_init_port(struct tport *);
static ssize_t udp_send(struct tport *, const u_char *, size_t,
const struct sockaddr *, size_t);
static ssize_t udp_recv(struct tport *, struct port_input *);
/* exported */
const struct transport_def udp_trans = {
"udp",
OIDX_begemotSnmpdTransUdp,
udp_start,
udp_stop,
udp_close_port,
udp_init_port,
udp_send,
udp_recv,
NULL
};
static struct transport *my_trans;
static int
udp_start(void)
{
return (trans_register(&udp_trans, &my_trans));
}
static int
udp_stop(int force __unused)
{
if (my_trans != NULL)
if (trans_unregister(my_trans) != 0)
return (SNMP_ERR_GENERR);
return (SNMP_ERR_NOERROR);
}
/*
* A UDP port is ready
*/
static void
udp_input(int fd __unused, void *udata)
{
struct udp_port *p = udata;
p->input.peerlen = sizeof(p->ret);
snmpd_input(&p->input, &p->tport);
}
/*
* Create a UDP socket and bind it to the given port
*/
static int
udp_init_port(struct tport *tp)
{
struct udp_port *p = (struct udp_port *)tp;
struct sockaddr_in addr;
u_int32_t ip;
const int on = 1;
if ((p->input.fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
syslog(LOG_ERR, "creating UDP socket: %m");
return (SNMP_ERR_RES_UNAVAIL);
}
ip = (p->addr[0] << 24) | (p->addr[1] << 16) | (p->addr[2] << 8) |
p->addr[3];
memset(&addr, 0, sizeof(addr));
addr.sin_addr.s_addr = htonl(ip);
addr.sin_port = htons(p->port);
addr.sin_family = AF_INET;
addr.sin_len = sizeof(addr);
if (addr.sin_addr.s_addr == INADDR_ANY) {
if (setsockopt(p->input.fd, IPPROTO_IP, IP_RECVDSTADDR, &on,
sizeof(on)) == -1) {
syslog(LOG_ERR, "setsockopt(IP_RECVDSTADDR): %m");
close(p->input.fd);
p->input.fd = -1;
return (SNMP_ERR_GENERR);
}
p->recvdstaddr = true;
}
if (bind(p->input.fd, (struct sockaddr *)&addr, sizeof(addr))) {
if (errno == EADDRNOTAVAIL) {
close(p->input.fd);
p->input.fd = -1;
return (SNMP_ERR_INCONS_NAME);
}
syslog(LOG_ERR, "bind: %s:%u %m", inet_ntoa(addr.sin_addr),
p->port);
close(p->input.fd);
p->input.fd = -1;
return (SNMP_ERR_GENERR);
}
if ((p->input.id = fd_select(p->input.fd, udp_input,
p, NULL)) == NULL) {
close(p->input.fd);
p->input.fd = -1;
return (SNMP_ERR_GENERR);
}
return (SNMP_ERR_NOERROR);
}
/*
* Create a new SNMP Port object and start it, if we are not
* in initialization mode. The arguments are in host byte order.
*/
static int
udp_open_port(u_int8_t *addr, u_int32_t udp_port, struct udp_port **pp)
{
struct udp_port *port;
int err;
if (udp_port > 0xffff)
return (SNMP_ERR_NO_CREATION);
if ((port = malloc(sizeof(*port))) == NULL)
return (SNMP_ERR_GENERR);
memset(port, 0, sizeof(*port));
/* initialize common part */
port->tport.index.len = 5;
port->tport.index.subs[0] = addr[0];
port->tport.index.subs[1] = addr[1];
port->tport.index.subs[2] = addr[2];
port->tport.index.subs[3] = addr[3];
port->tport.index.subs[4] = udp_port;
port->addr[0] = addr[0];
port->addr[1] = addr[1];
port->addr[2] = addr[2];
port->addr[3] = addr[3];
port->port = udp_port;
port->input.fd = -1;
port->input.id = NULL;
port->input.stream = 0;
port->input.cred = 0;
port->input.peer = (struct sockaddr *)&port->ret;
port->input.peerlen = sizeof(port->ret);
trans_insert_port(my_trans, &port->tport);
if (community != COMM_INITIALIZE &&
(err = udp_init_port(&port->tport)) != SNMP_ERR_NOERROR) {
udp_close_port(&port->tport);
return (err);
}
*pp = port;
return (SNMP_ERR_NOERROR);
}
/*
* Close an SNMP port
*/
static void
udp_close_port(struct tport *tp)
{
struct udp_port *port = (struct udp_port *)tp;
snmpd_input_close(&port->input);
trans_remove_port(tp);
free(port);
}
/*
* Send something
*/
static ssize_t
udp_send(struct tport *tp, const u_char *buf, size_t len,
const struct sockaddr *addr, size_t addrlen)
{
struct udp_port *p = (struct udp_port *)tp;
struct cmsghdr *cmsg;
struct msghdr msg;
char cbuf[CMSG_SPACE(sizeof(struct in_addr))];
struct iovec iov;
iov.iov_base = __DECONST(void*, buf);
iov.iov_len = len;
msg.msg_flags = 0;
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_name = __DECONST(void *, addr);
msg.msg_namelen = addrlen;
if (p->recvdstaddr) {
msg.msg_control = cbuf;
msg.msg_controllen = sizeof(cbuf);
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_level = IPPROTO_IP;
cmsg->cmsg_type = IP_SENDSRCADDR;
cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_addr));
memcpy(CMSG_DATA(cmsg), &p->dstaddr, sizeof(struct in_addr));
} else {
msg.msg_control = NULL;
msg.msg_controllen = 0;
}
return (sendmsg(p->input.fd, &msg, 0));
}
static void
check_priv_dgram(struct port_input *pi, struct sockcred *cred)
{
/* process explicitly sends credentials */
if (cred)
pi->priv = (cred->sc_euid == 0);
else
pi->priv = 0;
}
/*
* Input from a datagram socket.
* Each receive should return one datagram.
*/
static ssize_t
udp_recv(struct tport *tp, struct port_input *pi)
{
u_char embuf[1000];
char cbuf[CMSG_SPACE(SOCKCREDSIZE(CMGROUP_MAX)) +
CMSG_SPACE(sizeof(struct in_addr))];
struct udp_port *p = (struct udp_port *)tp;
struct msghdr msg;
struct iovec iov[1];
ssize_t len;
struct cmsghdr *cmsg;
struct sockcred *cred = NULL;
if (pi->buf == NULL) {
/* no buffer yet - allocate one */
if ((pi->buf = buf_alloc(0)) == NULL) {
/* ups - could not get buffer. Read away input
* and drop it */
(void)recvfrom(pi->fd, embuf, sizeof(embuf),
0, NULL, NULL);
/* return error */
return (-1);
}
pi->buflen = buf_size(0);
}
/* try to get a message */
msg.msg_name = pi->peer;
msg.msg_namelen = pi->peerlen;
msg.msg_iov = iov;
msg.msg_iovlen = 1;
memset(cbuf, 0, sizeof(cbuf));
msg.msg_control = cbuf;
msg.msg_controllen = sizeof(cbuf);
msg.msg_flags = 0;
iov[0].iov_base = pi->buf;
iov[0].iov_len = pi->buflen;
len = recvmsg(pi->fd, &msg, 0);
if (len == -1 || len == 0)
/* receive error */
return (-1);
if (msg.msg_flags & MSG_TRUNC) {
/* truncated - drop */
snmpd_stats.silentDrops++;
snmpd_stats.inTooLong++;
return (-1);
}
pi->length = (size_t)len;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == IPPROTO_IP &&
cmsg->cmsg_type == IP_RECVDSTADDR)
memcpy(&p->dstaddr, CMSG_DATA(cmsg),
sizeof(struct in_addr));
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_CREDS)
cred = (struct sockcred *)(void *)CMSG_DATA(cmsg);
}
if (pi->cred)
check_priv_dgram(pi, cred);
return (0);
}
/*
* Port table
*/
int
op_snmp_port(struct snmp_context *ctx, struct snmp_value *value,
u_int sub, u_int iidx, enum snmp_op op)
{
asn_subid_t which = value->var.subs[sub-1];
struct udp_port *p;
u_int8_t addr[4];
u_int32_t port;
switch (op) {
case SNMP_OP_GETNEXT:
if ((p = (struct udp_port *)trans_next_port(my_trans,
&value->var, sub)) == NULL)
return (SNMP_ERR_NOSUCHNAME);
index_append(&value->var, sub, &p->tport.index);
break;
case SNMP_OP_GET:
if ((p = (struct udp_port *)trans_find_port(my_trans,
&value->var, sub)) == NULL)
return (SNMP_ERR_NOSUCHNAME);
break;
case SNMP_OP_SET:
p = (struct udp_port *)trans_find_port(my_trans,
&value->var, sub);
ctx->scratch->int1 = (p != NULL);
if (which != LEAF_begemotSnmpdPortStatus)
abort();
if (!TRUTH_OK(value->v.integer))
return (SNMP_ERR_WRONG_VALUE);
ctx->scratch->int2 = TRUTH_GET(value->v.integer);
if (ctx->scratch->int2) {
/* open an SNMP port */
if (p != NULL)
/* already open - do nothing */
return (SNMP_ERR_NOERROR);
if (index_decode(&value->var, sub, iidx, addr, &port))
return (SNMP_ERR_NO_CREATION);
return (udp_open_port(addr, port, &p));
} else {
/* close SNMP port - do in commit */
}
return (SNMP_ERR_NOERROR);
case SNMP_OP_ROLLBACK:
p = (struct udp_port *)trans_find_port(my_trans,
&value->var, sub);
if (ctx->scratch->int1 == 0) {
/* did not exist */
if (ctx->scratch->int2 == 1) {
/* created */
if (p != NULL)
udp_close_port(&p->tport);
}
}
return (SNMP_ERR_NOERROR);
case SNMP_OP_COMMIT:
p = (struct udp_port *)trans_find_port(my_trans,
&value->var, sub);
if (ctx->scratch->int1 == 1) {
/* did exist */
if (ctx->scratch->int2 == 0) {
/* delete */
if (p != NULL)
udp_close_port(&p->tport);
}
}
return (SNMP_ERR_NOERROR);
default:
abort();
}
/*
* Come here to fetch the value
*/
switch (which) {
case LEAF_begemotSnmpdPortStatus:
value->v.integer = 1;
break;
default:
abort();
}
return (SNMP_ERR_NOERROR);
}