msg.c

OpenSSH 是 SSH （Secure SHell） 协议的免费开源实现。它用安全、加密的网络连接工具代替了 telnet、ftp、 rlogin、rsh 和 rcp 工具。OpenSSH 支持

/*
 * Copyright (c) 2002 Markus Friedl.  All rights reserved.
 *
 * 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 THE AUTHOR ``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 THE AUTHOR 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.
 */
#include "includes.h"
RCSID("$OpenBSD: msg.c,v 1.7 2003/11/17 09:45:39 djm Exp $");

#include "buffer.h"
#include "getput.h"
#include "log.h"
#include "atomicio.h"
#include "msg.h"

int
ssh_msg_send(int fd, u_char type, Buffer *m)
{
	u_char buf[5];
	u_int mlen = buffer_len(m);

	debug3("ssh_msg_send: type %u", (unsigned int)type & 0xff);

	PUT_32BIT(buf, mlen + 1);
	buf[4] = type;		/* 1st byte of payload is mesg-type */
	if (atomicio(vwrite, fd, buf, sizeof(buf)) != sizeof(buf)) {
		error("ssh_msg_send: write");
		return (-1);
	}
	if (atomicio(vwrite, fd, buffer_ptr(m), mlen) != mlen) {
		error("ssh_msg_send: write");
		return (-1);
	}
	return (0);
}

int
ssh_msg_recv(int fd, Buffer *m)
{
	u_char buf[4];
	ssize_t res;
	u_int msg_len;

	debug3("ssh_msg_recv entering");

	res = atomicio(read, fd, buf, sizeof(buf));
	if (res != sizeof(buf)) {
		if (res != 0)
			error("ssh_msg_recv: read: header %ld", (long)res);
		return (-1);
	}
	msg_len = GET_32BIT(buf);
	if (msg_len > 256 * 1024) {
		error("ssh_msg_recv: read: bad msg_len %u", msg_len);
		return (-1);
	}
	buffer_clear(m);
	buffer_append_space(m, msg_len);
	res = atomicio(read, fd, buffer_ptr(m), msg_len);
	if (res != msg_len) {
		error("ssh_msg_recv: read: %ld != msg_len", (long)res);
		return (-1);
	}
	return (0);
}