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/* $OpenBSD: demand.c,v 1.11 2015/01/16 06:40:19 deraadt Exp $ */ |
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/* |
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* demand.c - Support routines for demand-dialling. |
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* |
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* Copyright (c) 1989-2002 Paul Mackerras. All rights reserved. |
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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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* |
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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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* |
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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 |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* |
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* 3. The name(s) of the authors of this software must not be used to |
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* endorse or promote products derived from this software without |
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* prior written permission. |
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* |
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* 4. Redistributions of any form whatsoever must retain the following |
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* acknowledgment: |
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* "This product includes software developed by Paul Mackerras |
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* <paulus@samba.org>". |
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* |
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* THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO |
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* THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY |
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* AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY |
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* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN |
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* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING |
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* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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*/ |
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#include <sys/types.h> |
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#include <sys/wait.h> |
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#include <sys/time.h> |
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#include <sys/resource.h> |
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#include <sys/stat.h> |
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#include <sys/socket.h> |
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#ifdef PPP_FILTER |
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#include <net/if.h> |
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#include <net/bpf.h> |
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#include <pcap.h> |
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#endif |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <errno.h> |
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#include <fcntl.h> |
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#include <syslog.h> |
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#include "pppd.h" |
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#include "fsm.h" |
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#include "ipcp.h" |
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#include "lcp.h" |
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char *frame; |
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int framelen; |
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int framemax; |
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int escape_flag; |
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int flush_flag; |
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int fcs; |
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struct packet { |
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int length; |
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struct packet *next; |
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unsigned char data[1]; |
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}; |
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struct packet *pend_q; |
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struct packet *pend_qtail; |
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static int active_packet(unsigned char *, int); |
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/* |
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* demand_conf - configure the interface for doing dial-on-demand. |
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*/ |
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void |
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demand_conf() |
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{ |
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int i; |
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struct protent *protp; |
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/* framemax = lcp_allowoptions[0].mru; |
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if (framemax < PPP_MRU) */ |
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framemax = PPP_MRU; |
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framemax += PPP_HDRLEN + PPP_FCSLEN; |
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frame = malloc(framemax); |
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if (frame == NULL) |
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novm("demand frame"); |
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framelen = 0; |
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pend_q = NULL; |
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escape_flag = 0; |
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flush_flag = 0; |
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fcs = PPP_INITFCS; |
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ppp_send_config(0, PPP_MRU, (u_int32_t) 0, 0, 0); |
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ppp_recv_config(0, PPP_MRU, (u_int32_t) 0, 0, 0); |
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#ifdef PPP_FILTER |
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set_filters(&pass_filter, &active_filter); |
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#endif |
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/* |
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* Call the demand_conf procedure for each protocol that's got one. |
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*/ |
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for (i = 0; (protp = protocols[i]) != NULL; ++i) |
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if (protp->enabled_flag && protp->demand_conf != NULL) |
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if (!((*protp->demand_conf)(0))) |
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die(1); |
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} |
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/* |
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* demand_drop - set each network protocol to discard packets |
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* without an error. |
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*/ |
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void |
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demand_drop() |
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{ |
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struct packet *pkt, *nextpkt; |
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int i; |
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struct protent *protp; |
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for (i = 0; (protp = protocols[i]) != NULL; ++i) |
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if (protp->enabled_flag && protp->demand_conf != NULL) |
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sifnpmode(0, protp->protocol & ~0x8000, NPMODE_DROP); |
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get_loop_output(); |
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/* discard all saved packets */ |
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for (pkt = pend_q; pkt != NULL; pkt = nextpkt) { |
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nextpkt = pkt->next; |
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free(pkt); |
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} |
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pend_q = NULL; |
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framelen = 0; |
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flush_flag = 0; |
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escape_flag = 0; |
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fcs = PPP_INITFCS; |
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} |
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/* |
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* demand_unblock - set each enabled network protocol to pass packets. |
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*/ |
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void |
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demand_unblock() |
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{ |
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int i; |
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struct protent *protp; |
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for (i = 0; (protp = protocols[i]) != NULL; ++i) |
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if (protp->enabled_flag && protp->demand_conf != NULL) |
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sifnpmode(0, protp->protocol & ~0x8000, NPMODE_PASS); |
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} |
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/* |
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* FCS lookup table as calculated by genfcstab. |
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*/ |
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static u_short fcstab[256] = { |
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0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, |
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0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7, |
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0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, |
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0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876, |
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0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd, |
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0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5, |
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0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, |
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0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974, |
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0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, |
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0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3, |
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0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a, |
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0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72, |
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0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, |
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0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1, |
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0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738, |
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0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70, |
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0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7, |
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0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff, |
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0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, |
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0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e, |
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0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5, |
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0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd, |
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0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134, |
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0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c, |
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0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, |
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0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb, |
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0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, |
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0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, |
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0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1, |
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0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9, |
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0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, |
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0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78 |
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}; |
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/* |
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* loop_chars - process characters received from the loopback. |
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* Calls loop_frame when a complete frame has been accumulated. |
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* Return value is 1 if we need to bring up the link, 0 otherwise. |
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*/ |
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int |
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loop_chars(p, n) |
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unsigned char *p; |
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int n; |
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{ |
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int c, rv; |
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rv = 0; |
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for (; n > 0; --n) { |
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c = *p++; |
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if (c == PPP_FLAG) { |
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if (!escape_flag && !flush_flag |
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&& framelen > 2 && fcs == PPP_GOODFCS) { |
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framelen -= 2; |
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if (loop_frame(frame, framelen)) |
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rv = 1; |
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} |
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framelen = 0; |
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flush_flag = 0; |
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escape_flag = 0; |
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fcs = PPP_INITFCS; |
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continue; |
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} |
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if (flush_flag) |
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continue; |
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if (escape_flag) { |
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c ^= PPP_TRANS; |
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escape_flag = 0; |
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} else if (c == PPP_ESCAPE) { |
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escape_flag = 1; |
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continue; |
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} |
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if (framelen >= framemax) { |
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flush_flag = 1; |
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continue; |
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} |
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frame[framelen++] = c; |
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fcs = PPP_FCS(fcs, c); |
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} |
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return rv; |
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} |
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/* |
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* loop_frame - given a frame obtained from the loopback, |
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* decide whether to bring up the link or not, and, if we want |
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* to transmit this frame later, put it on the pending queue. |
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* Return value is 1 if we need to bring up the link, 0 otherwise. |
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* We assume that the kernel driver has already applied the |
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* pass_filter, so we won't get packets it rejected. |
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* We apply the active_filter to see if we want this packet to |
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* bring up the link. |
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*/ |
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int |
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loop_frame(frame, len) |
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unsigned char *frame; |
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int len; |
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{ |
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struct packet *pkt; |
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/* log_packet(frame, len, "from loop: ", LOG_DEBUG); */ |
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if (len < PPP_HDRLEN) |
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return 0; |
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if ((PPP_PROTOCOL(frame) & 0x8000) != 0) |
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return 0; /* shouldn't get any of these anyway */ |
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if (!active_packet(frame, len)) |
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return 0; |
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pkt = (struct packet *) malloc(sizeof(struct packet) + len); |
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if (pkt != NULL) { |
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pkt->length = len; |
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pkt->next = NULL; |
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memcpy(pkt->data, frame, len); |
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if (pend_q == NULL) |
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pend_q = pkt; |
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else |
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pend_qtail->next = pkt; |
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pend_qtail = pkt; |
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} |
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return 1; |
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} |
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283 |
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/* |
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* demand_rexmit - Resend all those frames which we got via the |
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* loopback, now that the real serial link is up. |
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*/ |
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void |
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demand_rexmit(proto) |
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int proto; |
290 |
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{ |
291 |
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struct packet *pkt, *prev, *nextpkt; |
292 |
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293 |
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prev = NULL; |
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pkt = pend_q; |
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pend_q = NULL; |
296 |
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for (; pkt != NULL; pkt = nextpkt) { |
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nextpkt = pkt->next; |
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if (PPP_PROTOCOL(pkt->data) == proto) { |
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output(0, pkt->data, pkt->length); |
300 |
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free(pkt); |
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} else { |
302 |
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if (prev == NULL) |
303 |
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pend_q = pkt; |
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else |
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prev->next = pkt; |
306 |
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prev = pkt; |
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} |
308 |
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} |
309 |
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pend_qtail = prev; |
310 |
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if (prev != NULL) |
311 |
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prev->next = NULL; |
312 |
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} |
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314 |
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/* |
315 |
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* Scan a packet to decide whether it is an "active" packet, |
316 |
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* that is, whether it is worth bringing up the link for. |
317 |
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*/ |
318 |
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static int |
319 |
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active_packet(p, len) |
320 |
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unsigned char *p; |
321 |
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int len; |
322 |
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{ |
323 |
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int proto, i; |
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struct protent *protp; |
325 |
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326 |
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if (len < PPP_HDRLEN) |
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return 0; |
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proto = PPP_PROTOCOL(p); |
329 |
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#ifdef PPP_FILTER |
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if (active_filter.bf_len != 0 |
331 |
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&& bpf_filter(active_filter.bf_insns, frame, len, len) == 0) |
332 |
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return 0; |
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#endif |
334 |
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for (i = 0; (protp = protocols[i]) != NULL; ++i) { |
335 |
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if (protp->protocol < 0xC000 && (protp->protocol & ~0x8000) == proto) { |
336 |
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if (!protp->enabled_flag) |
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return 0; |
338 |
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if (protp->active_pkt == NULL) |
339 |
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return 1; |
340 |
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return (*protp->active_pkt)(p, len); |
341 |
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} |
342 |
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} |
343 |
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return 0; /* not a supported protocol !!?? */ |
344 |
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} |