429 lines
9.9 KiB
C
429 lines
9.9 KiB
C
/*
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* Copyright (c) 1989 Jan-Simon Pendry
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* Copyright (c) 1989 Imperial College of Science, Technology & Medicine
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Jan-Simon Pendry at Imperial College, London.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)rpc_fwd.c 8.1 (Berkeley) 6/6/93
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* $Id: rpc_fwd.c,v 1.3 1994/06/13 20:47:58 mycroft Exp $
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*/
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/*
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* RPC packet forwarding
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*/
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#include "am.h"
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#include <sys/ioctl.h>
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#ifndef F_SETFL
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#include <fcntl.h>
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#endif /* F_SETFL */
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#ifndef FNDELAY
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#include <sys/file.h>
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#endif /* FNDELAY */
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/*
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* Note that the ID field in the external packet is only
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* ever treated as a 32 bit opaque data object, so there
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* is no need to convert to and from network byte ordering.
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*/
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/*
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* Each pending reply has an rpc_forward structure
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* associated with it. These have a 15 second lifespan.
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* If a new structure is required, then an expired
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* one will be re-allocated if available, otherwise a fresh
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* one is allocated. Whenever a reply is received the
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* structure is discarded.
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*/
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typedef struct rpc_forward rpc_forward;
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struct rpc_forward {
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qelem rf_q; /* Linked list */
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time_t rf_ttl; /* Time to live */
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u_int rf_xid; /* Packet id */
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u_int rf_oldid; /* Original packet id */
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fwd_fun rf_fwd; /* Forwarding function */
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voidp rf_ptr;
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struct sockaddr_in rf_sin;
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};
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/*
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* Head of list of pending replies
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*/
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extern qelem rpc_head;
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qelem rpc_head = { &rpc_head, &rpc_head };
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static u_int xid;
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#define XID_ALLOC() (xid++)
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#define MAX_PACKET_SIZE 8192 /* Maximum UDP packet size */
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int fwd_sock;
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/*
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* Allocate a rely structure
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*/
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static rpc_forward *fwd_alloc()
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{
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time_t now = clocktime();
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rpc_forward *p = 0, *p2;
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#ifdef DEBUG
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/*dlog("fwd_alloca: rpc_head = %#x", rpc_head.q_forw);*/
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#endif /* DEBUG */
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/*
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* First search for an existing expired one.
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*/
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ITER(p2, rpc_forward, &rpc_head) {
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if (p2->rf_ttl <= now) {
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p = p2;
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break;
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}
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}
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/*
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* If one couldn't be found then allocate
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* a new structure and link it at the
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* head of the list.
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*/
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if (p) {
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/*
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* Call forwarding function to say that
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* this message was junked.
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*/
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#ifdef DEBUG
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dlog("Re-using packet forwarding slot - id %#x", p->rf_xid);
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#endif /* DEBUG */
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if (p->rf_fwd)
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(*p->rf_fwd)(0, 0, 0, &p->rf_sin, p->rf_ptr, FALSE);
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rem_que(&p->rf_q);
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} else {
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p = ALLOC(rpc_forward);
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}
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ins_que(&p->rf_q, &rpc_head);
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/*
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* Set the time to live field
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* Timeout in 43 seconds
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*/
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p->rf_ttl = now + 43;
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#ifdef DEBUG
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/*dlog("fwd_alloca: rpc_head = %#x", rpc_head.q_forw);*/
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#endif /* DEBUG */
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return p;
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}
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/*
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* Free an allocated reply structure.
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* First unlink it from the list, then
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* discard it.
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*/
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static void fwd_free(p)
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rpc_forward *p;
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{
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#ifdef DEBUG
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/*dlog("fwd_free: rpc_head = %#x", rpc_head.q_forw);*/
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#endif /* DEBUG */
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rem_que(&p->rf_q);
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#ifdef DEBUG
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/*dlog("fwd_free: rpc_head = %#x", rpc_head.q_forw);*/
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#endif /* DEBUG */
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free((voidp) p);
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}
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/*
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* Initialise the RPC forwarder
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*/
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int fwd_init()
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{
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int on = 1;
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/*
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* Create ping socket
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*/
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fwd_sock = socket(AF_INET, SOCK_DGRAM, 0);
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if (fwd_sock < 0) {
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plog(XLOG_ERROR, "Unable to create RPC forwarding socket: %m");
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return errno;
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}
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/*
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* Some things we talk to require a priv port - so make one here
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*/
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if (bind_resv_port(fwd_sock, (unsigned short *) 0) < 0)
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plog(XLOG_ERROR, "can't bind privileged port");
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if (fcntl(fwd_sock, F_SETFL, FNDELAY) < 0 &&
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ioctl(fwd_sock, FIONBIO, &on) < 0) {
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plog(XLOG_ERROR, "Can't set non-block on forwarding socket: %m");
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return errno;
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}
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return 0;
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}
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/*
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* Locate a packet in the forwarding list
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*/
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static rpc_forward *fwd_locate(id)
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u_int id;
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{
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rpc_forward *p;
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ITER(p, rpc_forward, &rpc_head) {
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if (p->rf_xid == id)
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return p;
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}
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return 0;
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}
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/*
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* This is called to forward a packet to another
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* RPC server. The message id is changed and noted
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* so that when a reply appears we can tie it up
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* correctly. Just matching the reply's source address
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* would not work because it might come from a
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* different address.
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*/
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int fwd_packet(type_id, pkt, len, fwdto, replyto, i, cb)
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int type_id;
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voidp pkt;
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int len;
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struct sockaddr_in *fwdto, *replyto;
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voidp i;
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fwd_fun cb;
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{
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rpc_forward *p;
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u_int *pkt_int;
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int error;
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if ((int)amd_state >= (int)Finishing)
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return ENOENT;
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/*
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* See if the type_id is fully specified.
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* If so, then discard any old entries
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* for this id.
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* Otherwise make sure the type_id is
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* fully qualified by allocating an id here.
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*/
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#ifdef DEBUG
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switch (type_id & RPC_XID_MASK) {
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case RPC_XID_PORTMAP: dlog("Sending PORTMAP request"); break;
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case RPC_XID_MOUNTD: dlog("Sending MOUNTD request %#x", type_id); break;
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case RPC_XID_NFSPING: dlog("Sending NFS ping"); break;
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default: dlog("UNKNOWN RPC XID"); break;
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}
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#endif /* DEBUG */
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if (type_id & ~RPC_XID_MASK) {
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#ifdef DEBUG
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/*dlog("Fully qualified rpc type provided");*/
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#endif /* DEBUG */
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p = fwd_locate(type_id);
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if (p) {
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#ifdef DEBUG
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dlog("Discarding earlier rpc fwd handle");
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#endif /* DEBUG */
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fwd_free(p);
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}
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} else {
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#ifdef DEBUG
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dlog("Allocating a new xid...");
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#endif /* DEBUG */
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type_id = MK_RPC_XID(type_id, XID_ALLOC());
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}
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p = fwd_alloc();
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if (!p)
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return ENOBUFS;
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error = 0;
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pkt_int = (u_int *) pkt;
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/*
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* Get the original packet id
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*/
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p->rf_oldid = *pkt_int;
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/*
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* Replace with newly allocated id
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*/
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p->rf_xid = *pkt_int = type_id;
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/*
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* The sendto may fail if, for example, the route
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* to a remote host is lost because an intermediate
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* gateway has gone down. Important to fill in the
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* rest of "p" otherwise nasty things happen later...
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*/
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#ifdef DEBUG
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{ char dq[20];
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dlog("Sending packet id %#x to %s.%d", p->rf_xid, inet_dquad(dq, fwdto->sin_addr.s_addr), ntohs(fwdto->sin_port));
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}
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#endif /* DEBUG */
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if (sendto(fwd_sock, (char *) pkt, len, 0,
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(struct sockaddr *) fwdto, sizeof(*fwdto)) < 0)
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error = errno;
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/*
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* Save callback function and return address
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*/
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p->rf_fwd = cb;
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if (replyto)
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p->rf_sin = *replyto;
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else
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bzero((voidp) &p->rf_sin, sizeof(p->rf_sin));
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p->rf_ptr = i;
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return error;
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}
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/*
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* Called when some data arrives on the forwarding socket
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*/
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void fwd_reply()
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{
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int len;
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#ifdef DYNAMIC_BUFFERS
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voidp pkt;
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#else
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u_int pkt[MAX_PACKET_SIZE/sizeof(u_int)+1];
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#endif /* DYNAMIC_BUFFERS */
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u_int *pkt_int;
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int rc;
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rpc_forward *p;
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struct sockaddr_in src_addr;
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int src_addr_len;
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/*
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* Determine the length of the packet
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*/
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#ifdef DYNAMIC_BUFFERS
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if (ioctl(fwd_sock, FIONREAD, &len) < 0) {
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plog(XLOG_ERROR, "Error reading packet size: %m");
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return;
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}
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/*
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* Allocate a buffer
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*/
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pkt = (voidp) malloc((unsigned) len);
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if (!pkt) {
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plog(XLOG_ERROR, "Out of buffers in fwd_reply");
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return;
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}
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#else
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len = MAX_PACKET_SIZE;
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#endif /* DYNAMIC_BUFFERS */
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/*
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* Read the packet and check for validity
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*/
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again:
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src_addr_len = sizeof(src_addr);
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rc = recvfrom(fwd_sock, (char *) pkt, len, 0,
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(struct sockaddr *) &src_addr, &src_addr_len);
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if (rc < 0 || src_addr_len != sizeof(src_addr) ||
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src_addr.sin_family != AF_INET) {
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if (rc < 0 && errno == EINTR)
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goto again;
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plog(XLOG_ERROR, "Error reading RPC reply: %m");
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goto out;
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}
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#ifdef DYNAMIC_BUFFERS
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if (rc != len) {
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plog(XLOG_ERROR, "Short read in fwd_reply");
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goto out;
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}
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#endif /* DYNAMIC_BUFFERS */
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/*
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* Do no more work if finishing soon
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*/
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if ((int)amd_state >= (int)Finishing)
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goto out;
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/*
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* Find packet reference
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*/
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pkt_int = (u_int *) pkt;
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#ifdef DEBUG
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switch (*pkt_int & RPC_XID_MASK) {
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case RPC_XID_PORTMAP: dlog("Receiving PORTMAP reply"); break;
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case RPC_XID_MOUNTD: dlog("Receiving MOUNTD reply %#x", *pkt_int); break;
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case RPC_XID_NFSPING: dlog("Receiving NFS ping %#x", *pkt_int); break;
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default: dlog("UNKNOWN RPC XID"); break;
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}
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#endif /* DEBUG */
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p = fwd_locate(*pkt_int);
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if (!p) {
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#ifdef DEBUG
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dlog("Can't forward reply id %#x", *pkt_int);
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#endif /* DEBUG */
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goto out;
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}
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if (p->rf_fwd) {
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/*
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* Put the original message id back
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* into the packet.
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*/
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*pkt_int = p->rf_oldid;
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/*
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* Call forwarding function
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*/
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(*p->rf_fwd)((voidp) pkt, rc, &src_addr, &p->rf_sin, p->rf_ptr, TRUE);
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}
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/*
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* Free forwarding info
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*/
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fwd_free(p);
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out:;
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#ifdef DYNAMIC_BUFFERS
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/*
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* Free the packet
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*/
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free((voidp) pkt);
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#endif /* DYNAMIC_BUFFERS */
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}
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