[d0950ad] | 1 | /* |
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| 2 | * demand.c - Support routines for demand-dialling. |
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| 3 | * |
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| 4 | * Copyright (c) 1993 The Australian National University. |
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| 5 | * All rights reserved. |
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| 6 | * |
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| 7 | * Redistribution and use in source and binary forms are permitted |
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| 8 | * provided that the above copyright notice and this paragraph are |
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| 9 | * duplicated in all such forms and that any documentation, |
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| 10 | * advertising materials, and other materials related to such |
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| 11 | * distribution and use acknowledge that the software was developed |
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| 12 | * by the Australian National University. The name of the University |
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| 13 | * may not be used to endorse or promote products derived from this |
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| 14 | * software without specific prior written permission. |
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| 15 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
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| 16 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
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| 17 | * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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| 18 | */ |
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| 19 | |
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| 20 | #ifndef lint |
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| 21 | /* static char rcsid[] = "$Id$"; */ |
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| 22 | #endif |
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| 23 | |
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| 24 | #include <stdio.h> |
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| 25 | #include <stdlib.h> |
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| 26 | #include <string.h> |
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| 27 | #include <errno.h> |
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| 28 | #include <fcntl.h> |
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| 29 | #include <syslog.h> |
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| 30 | #include <netdb.h> |
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| 31 | #include <sys/param.h> |
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| 32 | #include <sys/types.h> |
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| 33 | #include <sys/wait.h> |
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| 34 | #include <sys/time.h> |
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| 35 | #include <sys/resource.h> |
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| 36 | #include <sys/stat.h> |
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| 37 | #include <sys/socket.h> |
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| 38 | #ifdef PPP_FILTER |
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| 39 | #include <net/if.h> |
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| 40 | #include <net/bpf.h> |
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| 41 | #include <pcap.h> |
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| 42 | #endif |
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| 43 | |
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| 44 | #include "pppd.h" |
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| 45 | #include "fsm.h" |
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| 46 | #include "ipcp.h" |
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| 47 | #include "lcp.h" |
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| 48 | |
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| 49 | char *frame; |
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| 50 | int framelen; |
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| 51 | int framemax; |
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| 52 | int escape_flag; |
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| 53 | int flush_flag; |
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| 54 | int fcs; |
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| 55 | |
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| 56 | struct packet { |
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| 57 | int length; |
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| 58 | struct packet *next; |
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| 59 | unsigned char data[1]; |
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| 60 | }; |
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| 61 | |
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| 62 | struct packet *pend_q; |
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| 63 | struct packet *pend_qtail; |
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| 64 | |
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| 65 | static int active_packet __P((unsigned char *, int)); |
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| 66 | |
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| 67 | /* |
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| 68 | * demand_conf - configure the interface for doing dial-on-demand. |
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| 69 | */ |
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| 70 | void |
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| 71 | demand_conf() |
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| 72 | { |
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| 73 | int i; |
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| 74 | struct protent *protp; |
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| 75 | |
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| 76 | /* framemax = lcp_allowoptions[0].mru; |
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| 77 | if (framemax < PPP_MRU) */ |
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| 78 | framemax = PPP_MRU; |
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| 79 | framemax += PPP_HDRLEN + PPP_FCSLEN; |
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| 80 | frame = malloc(framemax); |
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| 81 | if (frame == NULL) |
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| 82 | novm("demand frame"); |
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| 83 | framelen = 0; |
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| 84 | pend_q = NULL; |
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| 85 | escape_flag = 0; |
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| 86 | flush_flag = 0; |
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| 87 | fcs = PPP_INITFCS; |
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| 88 | |
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| 89 | ppp_send_config(0, PPP_MRU, (u_int32_t) 0, 0, 0); |
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| 90 | ppp_recv_config(0, PPP_MRU, (u_int32_t) 0, 0, 0); |
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| 91 | |
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| 92 | #ifdef PPP_FILTER |
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| 93 | set_filters(&pass_filter, &active_filter); |
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| 94 | #endif |
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| 95 | |
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| 96 | /* |
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| 97 | * Call the demand_conf procedure for each protocol that's got one. |
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| 98 | */ |
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| 99 | for (i = 0; (protp = protocols[i]) != NULL; ++i) |
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| 100 | if (protp->enabled_flag && protp->demand_conf != NULL) |
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| 101 | if (!((*protp->demand_conf)(0))) |
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| 102 | die(1); |
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| 103 | } |
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| 104 | |
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| 105 | |
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| 106 | /* |
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| 107 | * demand_block - set each network protocol to block further packets. |
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| 108 | */ |
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| 109 | void |
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| 110 | demand_block() |
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| 111 | { |
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| 112 | int i; |
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| 113 | struct protent *protp; |
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| 114 | |
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| 115 | for (i = 0; (protp = protocols[i]) != NULL; ++i) |
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| 116 | if (protp->enabled_flag && protp->demand_conf != NULL) |
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| 117 | sifnpmode(0, protp->protocol & ~0x8000, NPMODE_QUEUE); |
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| 118 | get_loop_output(); |
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| 119 | } |
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| 120 | |
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| 121 | /* |
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| 122 | * demand_discard - set each network protocol to discard packets |
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| 123 | * with an error. |
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| 124 | */ |
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| 125 | void |
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| 126 | demand_discard() |
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| 127 | { |
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| 128 | struct packet *pkt, *nextpkt; |
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| 129 | int i; |
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| 130 | struct protent *protp; |
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| 131 | |
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| 132 | for (i = 0; (protp = protocols[i]) != NULL; ++i) |
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| 133 | if (protp->enabled_flag && protp->demand_conf != NULL) |
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| 134 | sifnpmode(0, protp->protocol & ~0x8000, NPMODE_ERROR); |
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| 135 | get_loop_output(); |
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| 136 | |
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| 137 | /* discard all saved packets */ |
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| 138 | for (pkt = pend_q; pkt != NULL; pkt = nextpkt) { |
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| 139 | nextpkt = pkt->next; |
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| 140 | free(pkt); |
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| 141 | } |
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| 142 | pend_q = NULL; |
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| 143 | framelen = 0; |
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| 144 | flush_flag = 0; |
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| 145 | escape_flag = 0; |
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| 146 | fcs = PPP_INITFCS; |
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| 147 | } |
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| 148 | |
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| 149 | /* |
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| 150 | * demand_unblock - set each enabled network protocol to pass packets. |
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| 151 | */ |
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| 152 | void |
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| 153 | demand_unblock() |
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| 154 | { |
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| 155 | int i; |
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| 156 | struct protent *protp; |
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| 157 | |
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| 158 | for (i = 0; (protp = protocols[i]) != NULL; ++i) |
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| 159 | if (protp->enabled_flag && protp->demand_conf != NULL) |
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| 160 | sifnpmode(0, protp->protocol & ~0x8000, NPMODE_PASS); |
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| 161 | } |
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| 162 | |
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| 163 | /* |
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| 164 | * FCS lookup table as calculated by genfcstab. |
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| 165 | */ |
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| 166 | static u_short fcstab[256] = { |
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| 167 | 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, |
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| 168 | 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7, |
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| 169 | 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, |
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| 170 | 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876, |
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| 171 | 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd, |
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| 172 | 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5, |
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| 173 | 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, |
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| 174 | 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974, |
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| 175 | 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, |
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| 176 | 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3, |
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| 177 | 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a, |
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| 178 | 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72, |
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| 179 | 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, |
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| 180 | 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1, |
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| 181 | 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738, |
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| 182 | 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70, |
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| 183 | 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7, |
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| 184 | 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff, |
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| 185 | 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, |
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| 186 | 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e, |
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| 187 | 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5, |
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| 188 | 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd, |
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| 189 | 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134, |
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| 190 | 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c, |
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| 191 | 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, |
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| 192 | 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb, |
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| 193 | 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, |
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| 194 | 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, |
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| 195 | 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1, |
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| 196 | 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9, |
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| 197 | 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, |
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| 198 | 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78 |
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| 199 | }; |
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| 200 | |
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| 201 | /* |
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| 202 | * loop_chars - process characters received from the loopback. |
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| 203 | * Calls loop_frame when a complete frame has been accumulated. |
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| 204 | * Return value is 1 if we need to bring up the link, 0 otherwise. |
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| 205 | */ |
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| 206 | int |
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| 207 | loop_chars(p, n) |
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| 208 | unsigned char *p; |
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| 209 | int n; |
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| 210 | { |
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| 211 | int c, rv; |
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| 212 | |
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| 213 | rv = 0; |
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| 214 | for (; n > 0; --n) { |
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| 215 | c = *p++; |
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| 216 | if (c == PPP_FLAG) { |
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| 217 | if (!escape_flag && !flush_flag |
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| 218 | && framelen > 2 && fcs == PPP_GOODFCS) { |
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| 219 | framelen -= 2; |
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| 220 | if (loop_frame(frame, framelen)) |
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| 221 | rv = 1; |
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| 222 | } |
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| 223 | framelen = 0; |
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| 224 | flush_flag = 0; |
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| 225 | escape_flag = 0; |
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| 226 | fcs = PPP_INITFCS; |
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| 227 | continue; |
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| 228 | } |
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| 229 | if (flush_flag) |
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| 230 | continue; |
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| 231 | if (escape_flag) { |
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| 232 | c ^= PPP_TRANS; |
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| 233 | escape_flag = 0; |
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| 234 | } else if (c == PPP_ESCAPE) { |
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| 235 | escape_flag = 1; |
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| 236 | continue; |
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| 237 | } |
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| 238 | if (framelen >= framemax) { |
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| 239 | flush_flag = 1; |
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| 240 | continue; |
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| 241 | } |
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| 242 | frame[framelen++] = c; |
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| 243 | fcs = PPP_FCS(fcs, c); |
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| 244 | } |
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| 245 | return rv; |
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| 246 | } |
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| 247 | |
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| 248 | /* |
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| 249 | * loop_frame - given a frame obtained from the loopback, |
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| 250 | * decide whether to bring up the link or not, and, if we want |
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| 251 | * to transmit this frame later, put it on the pending queue. |
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| 252 | * Return value is 1 if we need to bring up the link, 0 otherwise. |
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| 253 | * We assume that the kernel driver has already applied the |
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| 254 | * pass_filter, so we won't get packets it rejected. |
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| 255 | * We apply the active_filter to see if we want this packet to |
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| 256 | * bring up the link. |
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| 257 | */ |
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| 258 | int |
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| 259 | loop_frame(frame, len) |
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| 260 | unsigned char *frame; |
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| 261 | int len; |
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| 262 | { |
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| 263 | struct packet *pkt; |
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| 264 | |
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| 265 | /* log_packet(frame, len, "from loop: ", LOG_DEBUG); */ |
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| 266 | if (len < PPP_HDRLEN) |
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| 267 | return 0; |
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| 268 | if ((PPP_PROTOCOL(frame) & 0x8000) != 0) |
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| 269 | return 0; /* shouldn't get any of these anyway */ |
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| 270 | if (!active_packet(frame, len)) |
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| 271 | return 0; |
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| 272 | |
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| 273 | pkt = (struct packet *) malloc(sizeof(struct packet) + len); |
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| 274 | if (pkt != NULL) { |
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| 275 | pkt->length = len; |
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| 276 | pkt->next = NULL; |
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| 277 | memcpy(pkt->data, frame, len); |
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| 278 | if (pend_q == NULL) |
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| 279 | pend_q = pkt; |
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| 280 | else |
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| 281 | pend_qtail->next = pkt; |
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| 282 | pend_qtail = pkt; |
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| 283 | } |
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| 284 | return 1; |
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| 285 | } |
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| 286 | |
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| 287 | /* |
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| 288 | * demand_rexmit - Resend all those frames which we got via the |
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| 289 | * loopback, now that the real serial link is up. |
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| 290 | */ |
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| 291 | void |
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| 292 | demand_rexmit(proto) |
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| 293 | int proto; |
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| 294 | { |
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| 295 | struct packet *pkt, *prev, *nextpkt; |
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| 296 | |
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| 297 | prev = NULL; |
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| 298 | pkt = pend_q; |
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| 299 | pend_q = NULL; |
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| 300 | for (; pkt != NULL; pkt = nextpkt) { |
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| 301 | nextpkt = pkt->next; |
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| 302 | if (PPP_PROTOCOL(pkt->data) == proto) { |
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| 303 | output(0, pkt->data, pkt->length); |
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| 304 | free(pkt); |
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| 305 | } else { |
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| 306 | if (prev == NULL) |
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| 307 | pend_q = pkt; |
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| 308 | else |
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| 309 | prev->next = pkt; |
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| 310 | prev = pkt; |
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| 311 | } |
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| 312 | } |
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| 313 | pend_qtail = prev; |
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| 314 | if (prev != NULL) |
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| 315 | prev->next = NULL; |
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| 316 | } |
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| 317 | |
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| 318 | /* |
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| 319 | * Scan a packet to decide whether it is an "active" packet, |
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| 320 | * that is, whether it is worth bringing up the link for. |
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| 321 | */ |
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| 322 | static int |
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| 323 | active_packet(p, len) |
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| 324 | unsigned char *p; |
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| 325 | int len; |
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| 326 | { |
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| 327 | int proto, i; |
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| 328 | struct protent *protp; |
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| 329 | |
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| 330 | if (len < PPP_HDRLEN) |
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| 331 | return 0; |
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| 332 | proto = PPP_PROTOCOL(p); |
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| 333 | #ifdef PPP_FILTER |
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| 334 | if (active_filter.bf_len != 0 |
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| 335 | && bpf_filter(active_filter.bf_insns, frame, len, len) == 0) |
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| 336 | return 0; |
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| 337 | #endif |
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| 338 | for (i = 0; (protp = protocols[i]) != NULL; ++i) { |
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| 339 | if (protp->protocol < 0xC000 && (protp->protocol & ~0x8000) == proto) { |
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| 340 | if (!protp->enabled_flag) |
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| 341 | return 0; |
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| 342 | if (protp->active_pkt == NULL) |
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| 343 | return 1; |
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| 344 | return (*protp->active_pkt)(p, len); |
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| 345 | } |
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| 346 | } |
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| 347 | return 0; /* not a supported protocol !!?? */ |
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| 348 | } |
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