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Refactor transport sources a bit to facilitate changes coming down pipeline

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Add recv callback to transport layer to better facilitate code reuse and
readability and for symmetry with send callback. Move recv_dgram and
recv_stream to udp_recv and lsock_recv, respectively, and make the
beforementioned functions recv callbacks for the udp and lsock transports,
respectively.

Consolidate the check_priv* functions in their relevant trans*.c source to
limit scope/use.

Note: this code is roughly based content from the submitter, although this
was modified to be more of a direct move from snmpd/main.c to the trans_*.c
sources, and to reduce unnecessary static function declarations.

MFC after:	2 weeks
Submitted by:	Thor Steingrimsson <thor.steingrimsson@isilon.com>
Sponsored by:	Dell EMC Isilon
This commit is contained in:
Enji Cooper 2016-12-26 10:17:22 +00:00
parent 70a3cc597a
commit 0ba351ef58
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=310586
4 changed files with 194 additions and 178 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

177
contrib/bsnmp/snmpd/main.c
View File

@ -1024,154 +1024,6 @@ snmp_input_consume(struct port_input *pi)
pi->length -= pi->consumed;
}
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;
}
static void
check_priv_stream(struct port_input *pi)
{
struct xucred ucred;
socklen_t ucredlen;
/* obtain the accept time credentials */
ucredlen = sizeof(ucred);
if (getsockopt(pi->fd, 0, LOCAL_PEERCRED, &ucred, &ucredlen) == 0 &&
ucredlen >= sizeof(ucred) && ucred.cr_version == XUCRED_VERSION)
pi->priv = (ucred.cr_uid == 0);
else
pi->priv = 0;
}
/*
* Input from a stream socket.
*/
static int
recv_stream(struct port_input *pi)
{
struct msghdr msg;
struct iovec iov[1];
ssize_t len;
if (pi->buf == NULL) {
/* no buffer yet - allocate one */
if ((pi->buf = buf_alloc(0)) == NULL) {
/* ups - could not get buffer. Return an error
* the caller must close the transport. */
return (-1);
}
pi->buflen = buf_size(0);
pi->consumed = 0;
pi->length = 0;
}
/* try to get a message */
msg.msg_name = pi->peer;
msg.msg_namelen = pi->peerlen;
msg.msg_iov = iov;
msg.msg_iovlen = 1;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
iov[0].iov_base = pi->buf + pi->length;
iov[0].iov_len = pi->buflen - pi->length;
len = recvmsg(pi->fd, &msg, 0);
if (len == -1 || len == 0)
/* receive error */
return (-1);
pi->length += len;
if (pi->cred)
check_priv_stream(pi);
return (0);
}
/*
* Input from a datagram socket.
* Each receive should return one datagram.
*/
static int
recv_dgram(struct port_input *pi, struct in_addr *laddr)
{
u_char embuf[1000];
char cbuf[CMSG_SPACE(SOCKCREDSIZE(CMGROUP_MAX)) +
CMSG_SPACE(sizeof(struct in_addr))];
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(laddr, CMSG_DATA(cmsg), sizeof(struct in_addr));
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_CREDS)
cred = (struct sockcred *)CMSG_DATA(cmsg);
}
if (pi->cred)
check_priv_dgram(pi, cred);
return (0);
}
/*
* Input from a socket
*/
@ -1191,35 +1043,8 @@ snmpd_input(struct port_input *pi, struct tport *tport)
#endif
struct msghdr msg;
struct iovec iov[1];
char cbuf[CMSG_SPACE(sizeof(struct in_addr))];
struct cmsghdr *cmsgp;
/* get input depending on the transport */
if (pi->stream) {
msg.msg_control = NULL;
msg.msg_controllen = 0;
ret = recv_stream(pi);
} else {
struct in_addr *laddr;
memset(cbuf, 0, CMSG_SPACE(sizeof(struct in_addr)));
msg.msg_control = cbuf;
msg.msg_controllen = CMSG_SPACE(sizeof(struct in_addr));
cmsgp = CMSG_FIRSTHDR(&msg);
cmsgp->cmsg_len = CMSG_LEN(sizeof(struct in_addr));
cmsgp->cmsg_level = IPPROTO_IP;
cmsgp->cmsg_type = IP_SENDSRCADDR;
laddr = (struct in_addr *)CMSG_DATA(cmsgp);
ret = recv_dgram(pi, laddr);
if (laddr->s_addr == 0) {
msg.msg_control = NULL;
msg.msg_controllen = 0;
}
}
ret = tport->transport->vtab->recv(pi);
if (ret == -1)
return (-1);

1
contrib/bsnmp/snmpd/snmpd.h
View File

@ -193,6 +193,7 @@ struct transport_def {
ssize_t (*send)(struct tport *, const u_char *, size_t,
const struct sockaddr *, size_t);
ssize_t (*recv)(struct port_input *);
};
struct transport {
struct asn_oid index; /* transport table index */

72
contrib/bsnmp/snmpd/trans_lsock.c
View File

@ -33,6 +33,7 @@
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/stat.h>
#include <sys/ucred.h>
#include <sys/un.h>
#include <errno.h>
@ -58,6 +59,7 @@ static void lsock_close_port(struct tport *);
static int lsock_init_port(struct tport *);
static ssize_t lsock_send(struct tport *, const u_char *, size_t,
const struct sockaddr *, size_t);
static ssize_t lsock_recv(struct port_input *);
/* exported */
const struct transport_def lsock_trans = {
@ -67,7 +69,8 @@ const struct transport_def lsock_trans = {
lsock_stop,
lsock_close_port,
lsock_init_port,
lsock_send
lsock_send,
lsock_recv
};
static struct transport *my_trans;
@ -421,6 +424,73 @@ lsock_send(struct tport *tp, const u_char *buf, size_t len,
return (sendto(peer->input.fd, buf, len, 0, addr, addrlen));
}
static void
check_priv_stream(struct port_input *pi)
{
struct xucred ucred;
socklen_t ucredlen;
/* obtain the accept time credentials */
ucredlen = sizeof(ucred);
if (getsockopt(pi->fd, 0, LOCAL_PEERCRED, &ucred, &ucredlen) == 0 &&
ucredlen >= sizeof(ucred) && ucred.cr_version == XUCRED_VERSION)
pi->priv = (ucred.cr_uid == 0);
else
pi->priv = 0;
}
/*
* Receive something
*/
static ssize_t
lsock_recv(struct port_input *pi)
{
struct msghdr msg;
struct iovec iov[1];
ssize_t len;
msg.msg_control = NULL;
msg.msg_controllen = 0;
if (pi->buf == NULL) {
/* no buffer yet - allocate one */
if ((pi->buf = buf_alloc(0)) == NULL) {
/* ups - could not get buffer. Return an error
* the caller must close the transport. */
return (-1);
}
pi->buflen = buf_size(0);
pi->consumed = 0;
pi->length = 0;
}
/* try to get a message */
msg.msg_name = pi->peer;
msg.msg_namelen = pi->peerlen;
msg.msg_iov = iov;
msg.msg_iovlen = 1;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
iov[0].iov_base = pi->buf + pi->length;
iov[0].iov_len = pi->buflen - pi->length;
len = recvmsg(pi->fd, &msg, 0);
if (len == -1 || len == 0)
/* receive error */
return (-1);
pi->length += len;
if (pi->cred)
check_priv_stream(pi);
return (0);
}
/*
* Dependency to create a lsock port
*/

122
contrib/bsnmp/snmpd/trans_udp.c
View File

@ -32,6 +32,7 @@
*/
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/ucred.h>
#include <stdlib.h>
#include <syslog.h>
@ -54,6 +55,7 @@ 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 port_input *);
/* exported */
const struct transport_def udp_trans = {
@ -63,7 +65,8 @@ const struct transport_def udp_trans = {
udp_stop,
udp_close_port,
udp_init_port,
udp_send
udp_send,
udp_recv
};
static struct transport *my_trans;
@ -218,6 +221,123 @@ udp_send(struct tport *tp, const u_char *buf, size_t len,
return (sendto(p->input.fd, buf, len, 0, addr, addrlen));
}
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 int
recv_dgram(struct port_input *pi, struct in_addr *laddr)
{
u_char embuf[1000];
char cbuf[CMSG_SPACE(SOCKCREDSIZE(CMGROUP_MAX)) +
CMSG_SPACE(sizeof(struct in_addr))];
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(laddr, CMSG_DATA(cmsg), sizeof(struct in_addr));
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_CREDS)
cred = (struct sockcred *)CMSG_DATA(cmsg);
}
if (pi->cred)
check_priv_dgram(pi, cred);
return (0);
}
/*
* Receive something
*/
static ssize_t
udp_recv(struct port_input *pi)
{
struct in_addr *laddr;
struct msghdr msg;
char cbuf[CMSG_SPACE(sizeof(struct in_addr))];
struct cmsghdr *cmsgp;
ssize_t ret;
memset(cbuf, 0, sizeof(cbuf));
msg.msg_control = cbuf;
msg.msg_controllen = sizeof(cbuf);
cmsgp = CMSG_FIRSTHDR(&msg);
cmsgp->cmsg_len = CMSG_LEN(sizeof(struct in_addr));
cmsgp->cmsg_level = IPPROTO_IP;
cmsgp->cmsg_type = IP_SENDSRCADDR;
laddr = (struct in_addr *)CMSG_DATA(cmsgp);
ret = recv_dgram(pi, laddr);
if (laddr->s_addr == INADDR_ANY) {
msg.msg_control = NULL;
msg.msg_controllen = 0;
}
return (ret);
}
/*
* Port table
*/