Start working on snmpd(8) and snmpctl(8), a lightweight SNMP implementation

for OpenBSD.  SNMP is a necessary evil.  This is work in progress, don't
expect too much from it yet.

ok deraadt@

1 files changed, 233 insertions, 0 deletions

diff --git a/usr.sbin/snmpd/imsg.c b/usr.sbin/snmpd/imsg.c
new file mode 100644
index 00000000000..83bb7262568
--- /dev/null
+++ b/usr.sbin/snmpd/imsg.c
@@ -0,0 +1,233 @@
+/*	$OpenBSD: imsg.c,v 1.1 2007/12/05 09:22:44 reyk Exp $	*/
+
+/*
+ * Copyright (c) 2003, 2004 Henning Brauer <henning@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/types.h>
+#include <sys/socket.h>
+#include <sys/queue.h>
+#include <sys/uio.h>
+#include <sys/param.h>
+#include <sys/tree.h>
+
+#include <net/if.h>
+
+#include <errno.h>
+#include <event.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "snmpd.h"
+
+void
+imsg_init(struct imsgbuf *ibuf, int fd, void (*handler)(int, short, void *))
+{
+	msgbuf_init(&ibuf->w);
+	bzero(&ibuf->r, sizeof(ibuf->r));
+	ibuf->fd = fd;
+	ibuf->w.fd = fd;
+	ibuf->pid = getpid();
+	ibuf->handler = handler;
+	TAILQ_INIT(&ibuf->fds);
+}
+
+ssize_t
+imsg_read(struct imsgbuf *ibuf)
+{
+	struct msghdr		 msg;
+	struct cmsghdr		*cmsg;
+	char			 cmsgbuf[CMSG_SPACE(sizeof(int) * 16)];
+	struct iovec		 iov;
+	ssize_t			 n;
+	int			 fd;
+	struct imsg_fd		*ifd;
+
+	bzero(&msg, sizeof(msg));
+
+	iov.iov_base = ibuf->r.buf + ibuf->r.wpos;
+	iov.iov_len = sizeof(ibuf->r.buf) - ibuf->r.wpos;
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+	msg.msg_control = cmsgbuf;
+	msg.msg_controllen = sizeof(cmsgbuf);
+
+	if ((n = recvmsg(ibuf->fd, &msg, 0)) == -1) {
+		if (errno != EINTR && errno != EAGAIN) {
+			log_warn("imsg_read: pipe read error");
+			return (-1);
+		}
+		return (-2);
+	}
+
+	ibuf->r.wpos += n;
+
+	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
+	    cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+		if (cmsg->cmsg_level == SOL_SOCKET &&
+		    cmsg->cmsg_type == SCM_RIGHTS) {
+			fd = (*(int *)CMSG_DATA(cmsg));
+			if ((ifd = calloc(1, sizeof(struct imsg_fd))) == NULL)
+				fatal("imsg_read calloc");
+			ifd->fd = fd;
+			TAILQ_INSERT_TAIL(&ibuf->fds, ifd, entry);
+		} else
+			log_warn("imsg_read: got unexpected ctl data level %d "
+			    "type %d", cmsg->cmsg_level, cmsg->cmsg_type);
+	}
+
+	return (n);
+}
+
+ssize_t
+imsg_get(struct imsgbuf *ibuf, struct imsg *imsg)
+{
+	size_t			 av, left, datalen;
+
+	av = ibuf->r.wpos;
+
+	if (IMSG_HEADER_SIZE > av)
+		return (0);
+
+	memcpy(&imsg->hdr, ibuf->r.buf, sizeof(imsg->hdr));
+	if (imsg->hdr.len < IMSG_HEADER_SIZE ||
+	    imsg->hdr.len > MAX_IMSGSIZE) {
+		log_warnx("imsg_get: imsg hdr len %u out of bounds, type=%u",
+		    imsg->hdr.len, imsg->hdr.type);
+		return (-1);
+	}
+	if (imsg->hdr.len > av)
+		return (0);
+	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
+	ibuf->r.rptr = ibuf->r.buf + IMSG_HEADER_SIZE;
+	if ((imsg->data = malloc(datalen)) == NULL) {
+		log_warn("imsg_get");
+		return (-1);
+	}
+	memcpy(imsg->data, ibuf->r.rptr, datalen);
+
+	if (imsg->hdr.len < av) {
+		left = av - imsg->hdr.len;
+		memmove(&ibuf->r.buf, ibuf->r.buf + imsg->hdr.len, left);
+		ibuf->r.wpos = left;
+	} else
+		ibuf->r.wpos = 0;
+
+	return (datalen + IMSG_HEADER_SIZE);
+}
+
+int
+imsg_compose(struct imsgbuf *ibuf, enum imsg_type type, u_int32_t peerid,
+    pid_t pid, int fd, void *data, u_int16_t datalen)
+{
+	struct buf	*wbuf;
+	int		 n;
+
+	if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL)
+		return (-1);
+
+	if (imsg_add(wbuf, data, datalen) == -1)
+		return (-1);
+
+	wbuf->fd = fd;
+
+	if ((n = imsg_close(ibuf, wbuf)) < 0)
+		return (-1);
+
+	return (n);
+}
+
+/* ARGSUSED */
+struct buf *
+imsg_create(struct imsgbuf *ibuf, enum imsg_type type, u_int32_t peerid,
+    pid_t pid, u_int16_t datalen)
+{
+	struct buf	*wbuf;
+	struct imsg_hdr	 hdr;
+
+	datalen += IMSG_HEADER_SIZE;
+	if (datalen > MAX_IMSGSIZE) {
+		log_warnx("imsg_create: len %u > MAX_IMSGSIZE; "
+		    "type %u peerid %lu", datalen + IMSG_HEADER_SIZE,
+		    type, peerid);
+		return (NULL);
+	}
+
+	hdr.type = type;
+	hdr.peerid = peerid;
+	if ((hdr.pid = pid) == 0)
+		hdr.pid = ibuf->pid;
+	if ((wbuf = buf_dynamic(datalen, MAX_IMSGSIZE)) == NULL) {
+		log_warn("imsg_create: buf_open");
+		return (NULL);
+	}
+	if (imsg_add(wbuf, &hdr, sizeof(hdr)) == -1)
+		return (NULL);
+
+	return (wbuf);
+}
+
+int
+imsg_add(struct buf *msg, void *data, u_int16_t datalen)
+{
+	if (datalen)
+		if (buf_add(msg, data, datalen) == -1) {
+			log_warnx("imsg_add: buf_add error");
+			buf_free(msg);
+			return (-1);
+		}
+	return (datalen);
+}
+
+int
+imsg_close(struct imsgbuf *ibuf, struct buf *msg)
+{
+	int		 n;
+	struct imsg_hdr	*hdr;
+
+	hdr = (struct imsg_hdr *)msg->buf;
+	hdr->len = (u_int16_t)msg->wpos;
+	if ((n = buf_close(&ibuf->w, msg)) < 0) {
+			log_warnx("imsg_close: buf_close error");
+			buf_free(msg);
+			return (-1);
+	}
+	imsg_event_add(ibuf);
+
+	return (n);
+}
+
+void
+imsg_free(struct imsg *imsg)
+{
+	free(imsg->data);
+}
+
+int
+imsg_get_fd(struct imsgbuf *ibuf)
+{
+	int		 fd;
+	struct imsg_fd	*ifd;
+
+	if ((ifd = TAILQ_FIRST(&ibuf->fds)) == NULL)
+		return (-1);
+
+	fd = ifd->fd;
+	TAILQ_REMOVE(&ibuf->fds, ifd, entry);
+	free(ifd);
+
+	return (fd);
+}