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/* |
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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. 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 1.10 2015/09/13 15:44:47 guenther 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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/* |
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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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void * 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 * |
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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); |
125 |
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126 |
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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; |
131 |
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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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138 |
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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 |
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fwd_free(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(p); |
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} |
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156 |
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/* |
157 |
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* Initialise the RPC forwarder |
158 |
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*/ |
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int fwd_init() |
160 |
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{ |
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/* |
162 |
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* Create ping socket |
163 |
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*/ |
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fwd_sock = socket(AF_INET, SOCK_DGRAM | SOCK_NONBLOCK, 0); |
165 |
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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; |
168 |
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} |
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170 |
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/* |
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* Some things we talk to require a priv port - so make one here |
172 |
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*/ |
173 |
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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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return 0; |
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} |
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179 |
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/* |
180 |
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* Locate a packet in the forwarding list |
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*/ |
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static rpc_forward * |
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fwd_locate(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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195 |
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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 |
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fwd_packet(int type_id, void *pkt, int len, struct sockaddr_in *fwdto, |
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struct sockaddr_in *replyto, void *i, 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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211 |
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if ((int)amd_state >= (int)Finishing) |
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return ENOENT; |
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214 |
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/* |
215 |
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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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} |
228 |
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#endif /* DEBUG */ |
229 |
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230 |
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if (type_id & ~RPC_XID_MASK) { |
231 |
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#ifdef DEBUG |
232 |
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/*dlog("Fully qualified rpc type provided");*/ |
233 |
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#endif /* DEBUG */ |
234 |
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p = fwd_locate(type_id); |
235 |
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if (p) { |
236 |
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#ifdef DEBUG |
237 |
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dlog("Discarding earlier rpc fwd handle"); |
238 |
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#endif /* DEBUG */ |
239 |
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fwd_free(p); |
240 |
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} |
241 |
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} else { |
242 |
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#ifdef DEBUG |
243 |
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dlog("Allocating a new xid..."); |
244 |
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#endif /* DEBUG */ |
245 |
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type_id = MK_RPC_XID(type_id, XID_ALLOC()); |
246 |
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} |
247 |
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248 |
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p = fwd_alloc(); |
249 |
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if (!p) |
250 |
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return ENOBUFS; |
251 |
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252 |
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error = 0; |
253 |
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254 |
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pkt_int = (u_int *) pkt; |
255 |
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256 |
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/* |
257 |
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* Get the original packet id |
258 |
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*/ |
259 |
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p->rf_oldid = *pkt_int; |
260 |
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261 |
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/* |
262 |
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* Replace with newly allocated id |
263 |
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*/ |
264 |
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p->rf_xid = *pkt_int = type_id; |
265 |
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266 |
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/* |
267 |
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* The sendto may fail if, for example, the route |
268 |
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* to a remote host is lost because an intermediate |
269 |
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* gateway has gone down. Important to fill in the |
270 |
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* rest of "p" otherwise nasty things happen later... |
271 |
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*/ |
272 |
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#ifdef DEBUG |
273 |
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{ char dq[20]; |
274 |
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275 |
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dlog("Sending packet id %#x to %s.%d", p->rf_xid, |
276 |
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inet_dquad(dq, sizeof(dq), fwdto->sin_addr.s_addr), |
277 |
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ntohs(fwdto->sin_port)); |
278 |
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} |
279 |
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#endif /* DEBUG */ |
280 |
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if (sendto(fwd_sock, (char *) pkt, len, 0, |
281 |
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(struct sockaddr *) fwdto, sizeof(*fwdto)) < 0) |
282 |
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error = errno; |
283 |
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284 |
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/* |
285 |
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* Save callback function and return address |
286 |
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*/ |
287 |
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p->rf_fwd = cb; |
288 |
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if (replyto) |
289 |
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p->rf_sin = *replyto; |
290 |
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else |
291 |
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bzero(&p->rf_sin, sizeof(p->rf_sin)); |
292 |
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p->rf_ptr = i; |
293 |
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294 |
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return error; |
295 |
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} |
296 |
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297 |
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/* |
298 |
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* Called when some data arrives on the forwarding socket |
299 |
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*/ |
300 |
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void |
301 |
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fwd_reply() |
302 |
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{ |
303 |
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int len; |
304 |
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#ifdef DYNAMIC_BUFFERS |
305 |
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void *pkt; |
306 |
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#else |
307 |
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u_int pkt[MAX_PACKET_SIZE/sizeof(u_int)+1]; |
308 |
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#endif /* DYNAMIC_BUFFERS */ |
309 |
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u_int *pkt_int; |
310 |
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int rc; |
311 |
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rpc_forward *p; |
312 |
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struct sockaddr_in src_addr; |
313 |
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socklen_t src_addr_len; |
314 |
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|
315 |
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/* |
316 |
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* Determine the length of the packet |
317 |
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*/ |
318 |
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#ifdef DYNAMIC_BUFFERS |
319 |
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if (ioctl(fwd_sock, FIONREAD, &len) < 0 || len < 0) { |
320 |
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plog(XLOG_ERROR, "Error reading packet size: %m"); |
321 |
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return; |
322 |
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} |
323 |
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324 |
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/* |
325 |
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* Allocate a buffer |
326 |
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*/ |
327 |
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pkt = malloc(len); |
328 |
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if (!pkt) { |
329 |
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plog(XLOG_ERROR, "Out of buffers in fwd_reply"); |
330 |
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return; |
331 |
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} |
332 |
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#else |
333 |
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len = MAX_PACKET_SIZE; |
334 |
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#endif /* DYNAMIC_BUFFERS */ |
335 |
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|
336 |
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/* |
337 |
|
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* Read the packet and check for validity |
338 |
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*/ |
339 |
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again: |
340 |
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src_addr_len = sizeof(src_addr); |
341 |
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rc = recvfrom(fwd_sock, (char *) pkt, len, 0, |
342 |
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(struct sockaddr *) &src_addr, &src_addr_len); |
343 |
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if (rc < 0 || src_addr_len != sizeof(src_addr) || |
344 |
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src_addr.sin_family != AF_INET) { |
345 |
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if (rc < 0 && errno == EINTR) |
346 |
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goto again; |
347 |
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plog(XLOG_ERROR, "Error reading RPC reply: %m"); |
348 |
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goto out; |
349 |
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} |
350 |
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|
351 |
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#ifdef DYNAMIC_BUFFERS |
352 |
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if (rc != len) { |
353 |
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plog(XLOG_ERROR, "Short read in fwd_reply"); |
354 |
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goto out; |
355 |
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} |
356 |
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#endif /* DYNAMIC_BUFFERS */ |
357 |
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|
358 |
|
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/* |
359 |
|
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* Do no more work if finishing soon |
360 |
|
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*/ |
361 |
|
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if ((int)amd_state >= (int)Finishing) |
362 |
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goto out; |
363 |
|
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|
364 |
|
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/* |
365 |
|
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* Find packet reference |
366 |
|
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*/ |
367 |
|
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pkt_int = (u_int *) pkt; |
368 |
|
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|
369 |
|
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#ifdef DEBUG |
370 |
|
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switch (*pkt_int & RPC_XID_MASK) { |
371 |
|
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case RPC_XID_PORTMAP: dlog("Receiving PORTMAP reply"); break; |
372 |
|
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case RPC_XID_MOUNTD: dlog("Receiving MOUNTD reply %#x", *pkt_int); break; |
373 |
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case RPC_XID_NFSPING: dlog("Receiving NFS ping %#x", *pkt_int); break; |
374 |
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default: dlog("UNKNOWN RPC XID"); break; |
375 |
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} |
376 |
|
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#endif /* DEBUG */ |
377 |
|
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|
378 |
|
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p = fwd_locate(*pkt_int); |
379 |
|
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if (!p) { |
380 |
|
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#ifdef DEBUG |
381 |
|
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dlog("Can't forward reply id %#x", *pkt_int); |
382 |
|
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#endif /* DEBUG */ |
383 |
|
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goto out; |
384 |
|
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} |
385 |
|
|
|
386 |
|
|
if (p->rf_fwd) { |
387 |
|
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/* |
388 |
|
|
* Put the original message id back |
389 |
|
|
* into the packet. |
390 |
|
|
*/ |
391 |
|
|
*pkt_int = p->rf_oldid; |
392 |
|
|
|
393 |
|
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/* |
394 |
|
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* Call forwarding function |
395 |
|
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*/ |
396 |
|
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(*p->rf_fwd)(pkt, rc, &src_addr, &p->rf_sin, p->rf_ptr, TRUE); |
397 |
|
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} |
398 |
|
|
|
399 |
|
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/* |
400 |
|
|
* Free forwarding info |
401 |
|
|
*/ |
402 |
|
|
fwd_free(p); |
403 |
|
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|
404 |
|
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out:; |
405 |
|
|
#ifdef DYNAMIC_BUFFERS |
406 |
|
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/* |
407 |
|
|
* Free the packet |
408 |
|
|
*/ |
409 |
|
|
free(pkt); |
410 |
|
|
#endif /* DYNAMIC_BUFFERS */ |
411 |
|
|
} |