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1/***********************************************************************
2*
3* ppp.c
4*
5* Implementation of user-space PPPoE redirector for Linux.
6*
7* Functions for talking to PPP daemon
8*
9* Copyright (C) 2000 by Roaring Penguin Software Inc.
10*
11* This program may be distributed according to the terms of the GNU
12* General Public License, version 2 or (at your option) any later version.
13*
14* LIC: GPL
15*
16***********************************************************************/
17
18static char const RCSID[] =
19"$Id$";
20
21#include "pppoe.h"
22
23#ifdef HAVE_SYSLOG_H
24#include <syslog.h>
25#include <android/log.h>
26#define syslog(prio, fmt...) \
27 __android_log_print(prio, "PPPOE", fmt)
28#endif
29
30#include <string.h>
31#include <errno.h>
32#include <stdlib.h>
33
34#ifdef HAVE_SYS_UIO_H
35#include <sys/uio.h>
36#endif
37
38#ifdef HAVE_UNISTD_H
39#include <unistd.h>
40#endif
41
42#ifdef HAVE_N_HDLC
43#ifndef N_HDLC
44#include <linux/termios.h>
45#endif
46#endif
47
48static int PPPState;
49static int PPPPacketSize;
50static unsigned char PPPXorValue;
51
52static UINT16_t const fcstab[256] = {
53 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
54 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
55 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
56 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
57 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
58 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
59 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
60 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
61 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
62 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
63 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
64 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
65 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
66 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
67 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
68 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
69 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
70 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
71 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
72 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
73 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
74 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
75 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
76 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
77 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
78 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
79 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
80 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
81 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
82 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
83 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
84 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
85};
86
87/**********************************************************************
88*%FUNCTION: syncReadFromPPP
89*%ARGUMENTS:
90* conn -- PPPoEConnection structure
91* packet -- buffer in which to place PPPoE packet
92*%RETURNS:
93* Nothing
94*%DESCRIPTION:
95* Reads from a synchronous PPP device and builds and transmits a PPPoE
96* packet
97***********************************************************************/
98void
99syncReadFromPPP(PPPoEConnection *conn, PPPoEPacket *packet)
100{
101 int r;
102#ifndef HAVE_N_HDLC
103 struct iovec vec[2];
104 unsigned char dummy[2];
105 vec[0].iov_base = (void *) dummy;
106 vec[0].iov_len = 2;
107 vec[1].iov_base = (void *) packet->payload;
108 vec[1].iov_len = ETH_DATA_LEN - PPPOE_OVERHEAD;
109
110 /* Use scatter-read to throw away the PPP frame address bytes */
111 r = readv(0, vec, 2);
112#else
113 /* Bloody hell... readv doesn't work with N_HDLC line discipline... GRR! */
114 unsigned char buf[ETH_DATA_LEN - PPPOE_OVERHEAD + 2];
115 r = read(0, buf, ETH_DATA_LEN - PPPOE_OVERHEAD + 2);
116 if (r >= 2) {
117 memcpy(packet->payload, buf+2, r-2);
118 }
119#endif
120 if (r < 0) {
121 /* Catch the Linux "select" bug */
122 if (errno == EAGAIN) {
123 rp_fatal("Linux select bug hit! This message is harmless, but please ask the Linux kernel developers to fix it.");
124 }
125 fatalSys("read (syncReadFromPPP)");
126 }
127 if (r == 0) {
128 syslog(LOG_INFO, "end-of-file in syncReadFromPPP");
129 sendPADT(conn, "RP-PPPoE: EOF in syncReadFromPPP");
130 exit(0);
131 }
132
133 if (r < 2) {
134 rp_fatal("too few characters read from PPP (syncReadFromPPP)");
135 }
136
137 sendSessionPacket(conn, packet, r-2);
138}
139
140/**********************************************************************
141*%FUNCTION: initPPP
142*%ARGUMENTS:
143* None
144*%RETURNS:
145* Nothing
146*%DESCRIPTION:
147* Initializes the PPP state machine
148***********************************************************************/
149void
150initPPP(void)
151{
152 PPPState = STATE_WAITFOR_FRAME_ADDR;
153 PPPPacketSize = 0;
154 PPPXorValue = 0;
155
156}
157/**********************************************************************
158*%FUNCTION: asyncReadFromPPP
159*%ARGUMENTS:
160* conn -- PPPoEConnection structure
161* packet -- buffer in which to place PPPoE packet
162*%RETURNS:
163* Nothing
164*%DESCRIPTION:
165* Reads from an async PPP device and builds a PPPoE packet to transmit
166***********************************************************************/
167void
168asyncReadFromPPP(PPPoEConnection *conn, PPPoEPacket *packet)
169{
170 unsigned char buf[READ_CHUNK];
171 unsigned char *ptr = buf;
172 unsigned char c;
173
174 int r;
175
176 r = read(0, buf, READ_CHUNK);
177 if (r < 0) {
178 fatalSys("read (asyncReadFromPPP)");
179 }
180
181 if (r == 0) {
182 syslog(LOG_INFO, "end-of-file in asyncReadFromPPP");
183 sendPADT(conn, "RP-PPPoE: EOF in asyncReadFromPPP");
184 exit(0);
185 }
186
187 while(r) {
188 if (PPPState == STATE_WAITFOR_FRAME_ADDR) {
189 while(r) {
190 --r;
191 if (*ptr++ == FRAME_ADDR) {
192 PPPState = STATE_DROP_PROTO;
193 break;
194 }
195 }
196 }
197
198 /* Still waiting... */
199 if (PPPState == STATE_WAITFOR_FRAME_ADDR) return;
200
201 while(r && PPPState == STATE_DROP_PROTO) {
202 --r;
203 if (*ptr++ == (FRAME_CTRL ^ FRAME_ENC)) {
204 PPPState = STATE_BUILDING_PACKET;
205 }
206 }
207
208 if (PPPState == STATE_DROP_PROTO) return;
209
210 /* Start building frame */
211 while(r && PPPState == STATE_BUILDING_PACKET) {
212 --r;
213 c = *ptr++;
214 switch(c) {
215 case FRAME_ESC:
216 PPPXorValue = FRAME_ENC;
217 break;
218 case FRAME_FLAG:
219 if (PPPPacketSize < 2) {
220 rp_fatal("Packet too short from PPP (asyncReadFromPPP)");
221 }
222 sendSessionPacket(conn, packet, PPPPacketSize-2);
223 PPPPacketSize = 0;
224 PPPXorValue = 0;
225 PPPState = STATE_WAITFOR_FRAME_ADDR;
226 break;
227 default:
228 if (PPPPacketSize >= ETH_DATA_LEN - 4) {
229 syslog(LOG_ERR, "Packet too big! Check MTU on PPP interface");
230 PPPPacketSize = 0;
231 PPPXorValue = 0;
232 PPPState = STATE_WAITFOR_FRAME_ADDR;
233 } else {
234 packet->payload[PPPPacketSize++] = c ^ PPPXorValue;
235 PPPXorValue = 0;
236 }
237 }
238 }
239 }
240}
241
242/**********************************************************************
243*%FUNCTION: pppFCS16
244*%ARGUMENTS:
245* fcs -- current fcs
246* cp -- a buffer's worth of data
247* len -- length of buffer "cp"
248*%RETURNS:
249* A new FCS
250*%DESCRIPTION:
251* Updates the PPP FCS.
252***********************************************************************/
253UINT16_t
254pppFCS16(UINT16_t fcs,
255 unsigned char * cp,
256 int len)
257{
258 while (len--)
259 fcs = (fcs >> 8) ^ fcstab[(fcs ^ *cp++) & 0xff];
260
261 return (fcs);
262}
263
generated by cgit at 2024-05-18 06:29:39 (GMT)