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982 lines
23 KiB
982 lines
23 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* |
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* Copyright (C) Hans Alblas PE1AYX <[email protected]> |
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* Copyright (C) 2004, 05 Ralf Baechle DL5RB <[email protected]> |
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* Copyright (C) 2004, 05 Thomas Osterried DL9SAU <[email protected]> |
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*/ |
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#include <linux/module.h> |
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#include <linux/bitops.h> |
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#include <linux/uaccess.h> |
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#include <linux/crc16.h> |
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#include <linux/string.h> |
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#include <linux/mm.h> |
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#include <linux/interrupt.h> |
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#include <linux/in.h> |
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#include <linux/inet.h> |
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#include <linux/slab.h> |
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#include <linux/tty.h> |
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#include <linux/errno.h> |
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#include <linux/netdevice.h> |
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#include <linux/major.h> |
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#include <linux/init.h> |
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#include <linux/rtnetlink.h> |
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#include <linux/etherdevice.h> |
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#include <linux/skbuff.h> |
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#include <linux/if_arp.h> |
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#include <linux/jiffies.h> |
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#include <linux/refcount.h> |
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#include <net/ax25.h> |
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#define AX_MTU 236 |
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/* SLIP/KISS protocol characters. */ |
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#define END 0300 /* indicates end of frame */ |
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#define ESC 0333 /* indicates byte stuffing */ |
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#define ESC_END 0334 /* ESC ESC_END means END 'data' */ |
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#define ESC_ESC 0335 /* ESC ESC_ESC means ESC 'data' */ |
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struct mkiss { |
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struct tty_struct *tty; /* ptr to TTY structure */ |
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struct net_device *dev; /* easy for intr handling */ |
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/* These are pointers to the malloc()ed frame buffers. */ |
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spinlock_t buflock;/* lock for rbuf and xbuf */ |
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unsigned char *rbuff; /* receiver buffer */ |
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int rcount; /* received chars counter */ |
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unsigned char *xbuff; /* transmitter buffer */ |
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unsigned char *xhead; /* pointer to next byte to XMIT */ |
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int xleft; /* bytes left in XMIT queue */ |
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/* Detailed SLIP statistics. */ |
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int mtu; /* Our mtu (to spot changes!) */ |
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int buffsize; /* Max buffers sizes */ |
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unsigned long flags; /* Flag values/ mode etc */ |
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/* long req'd: used by set_bit --RR */ |
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#define AXF_INUSE 0 /* Channel in use */ |
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#define AXF_ESCAPE 1 /* ESC received */ |
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#define AXF_ERROR 2 /* Parity, etc. error */ |
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#define AXF_KEEPTEST 3 /* Keepalive test flag */ |
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#define AXF_OUTWAIT 4 /* is outpacket was flag */ |
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int mode; |
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int crcmode; /* MW: for FlexNet, SMACK etc. */ |
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int crcauto; /* CRC auto mode */ |
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#define CRC_MODE_NONE 0 |
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#define CRC_MODE_FLEX 1 |
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#define CRC_MODE_SMACK 2 |
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#define CRC_MODE_FLEX_TEST 3 |
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#define CRC_MODE_SMACK_TEST 4 |
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refcount_t refcnt; |
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struct completion dead; |
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}; |
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/*---------------------------------------------------------------------------*/ |
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static const unsigned short crc_flex_table[] = { |
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0x0f87, 0x1e0e, 0x2c95, 0x3d1c, 0x49a3, 0x582a, 0x6ab1, 0x7b38, |
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0x83cf, 0x9246, 0xa0dd, 0xb154, 0xc5eb, 0xd462, 0xe6f9, 0xf770, |
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0x1f06, 0x0e8f, 0x3c14, 0x2d9d, 0x5922, 0x48ab, 0x7a30, 0x6bb9, |
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0x934e, 0x82c7, 0xb05c, 0xa1d5, 0xd56a, 0xc4e3, 0xf678, 0xe7f1, |
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0x2e85, 0x3f0c, 0x0d97, 0x1c1e, 0x68a1, 0x7928, 0x4bb3, 0x5a3a, |
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0xa2cd, 0xb344, 0x81df, 0x9056, 0xe4e9, 0xf560, 0xc7fb, 0xd672, |
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0x3e04, 0x2f8d, 0x1d16, 0x0c9f, 0x7820, 0x69a9, 0x5b32, 0x4abb, |
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0xb24c, 0xa3c5, 0x915e, 0x80d7, 0xf468, 0xe5e1, 0xd77a, 0xc6f3, |
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0x4d83, 0x5c0a, 0x6e91, 0x7f18, 0x0ba7, 0x1a2e, 0x28b5, 0x393c, |
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0xc1cb, 0xd042, 0xe2d9, 0xf350, 0x87ef, 0x9666, 0xa4fd, 0xb574, |
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0x5d02, 0x4c8b, 0x7e10, 0x6f99, 0x1b26, 0x0aaf, 0x3834, 0x29bd, |
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0xd14a, 0xc0c3, 0xf258, 0xe3d1, 0x976e, 0x86e7, 0xb47c, 0xa5f5, |
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0x6c81, 0x7d08, 0x4f93, 0x5e1a, 0x2aa5, 0x3b2c, 0x09b7, 0x183e, |
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0xe0c9, 0xf140, 0xc3db, 0xd252, 0xa6ed, 0xb764, 0x85ff, 0x9476, |
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0x7c00, 0x6d89, 0x5f12, 0x4e9b, 0x3a24, 0x2bad, 0x1936, 0x08bf, |
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0xf048, 0xe1c1, 0xd35a, 0xc2d3, 0xb66c, 0xa7e5, 0x957e, 0x84f7, |
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0x8b8f, 0x9a06, 0xa89d, 0xb914, 0xcdab, 0xdc22, 0xeeb9, 0xff30, |
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0x07c7, 0x164e, 0x24d5, 0x355c, 0x41e3, 0x506a, 0x62f1, 0x7378, |
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0x9b0e, 0x8a87, 0xb81c, 0xa995, 0xdd2a, 0xcca3, 0xfe38, 0xefb1, |
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0x1746, 0x06cf, 0x3454, 0x25dd, 0x5162, 0x40eb, 0x7270, 0x63f9, |
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0xaa8d, 0xbb04, 0x899f, 0x9816, 0xeca9, 0xfd20, 0xcfbb, 0xde32, |
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0x26c5, 0x374c, 0x05d7, 0x145e, 0x60e1, 0x7168, 0x43f3, 0x527a, |
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0xba0c, 0xab85, 0x991e, 0x8897, 0xfc28, 0xeda1, 0xdf3a, 0xceb3, |
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0x3644, 0x27cd, 0x1556, 0x04df, 0x7060, 0x61e9, 0x5372, 0x42fb, |
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0xc98b, 0xd802, 0xea99, 0xfb10, 0x8faf, 0x9e26, 0xacbd, 0xbd34, |
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0x45c3, 0x544a, 0x66d1, 0x7758, 0x03e7, 0x126e, 0x20f5, 0x317c, |
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0xd90a, 0xc883, 0xfa18, 0xeb91, 0x9f2e, 0x8ea7, 0xbc3c, 0xadb5, |
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0x5542, 0x44cb, 0x7650, 0x67d9, 0x1366, 0x02ef, 0x3074, 0x21fd, |
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0xe889, 0xf900, 0xcb9b, 0xda12, 0xaead, 0xbf24, 0x8dbf, 0x9c36, |
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0x64c1, 0x7548, 0x47d3, 0x565a, 0x22e5, 0x336c, 0x01f7, 0x107e, |
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0xf808, 0xe981, 0xdb1a, 0xca93, 0xbe2c, 0xafa5, 0x9d3e, 0x8cb7, |
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0x7440, 0x65c9, 0x5752, 0x46db, 0x3264, 0x23ed, 0x1176, 0x00ff |
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}; |
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static unsigned short calc_crc_flex(unsigned char *cp, int size) |
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{ |
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unsigned short crc = 0xffff; |
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while (size--) |
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crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff]; |
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return crc; |
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} |
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static int check_crc_flex(unsigned char *cp, int size) |
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{ |
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unsigned short crc = 0xffff; |
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if (size < 3) |
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return -1; |
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while (size--) |
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crc = (crc << 8) ^ crc_flex_table[((crc >> 8) ^ *cp++) & 0xff]; |
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if ((crc & 0xffff) != 0x7070) |
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return -1; |
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return 0; |
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} |
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static int check_crc_16(unsigned char *cp, int size) |
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{ |
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unsigned short crc = 0x0000; |
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if (size < 3) |
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return -1; |
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crc = crc16(0, cp, size); |
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if (crc != 0x0000) |
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return -1; |
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return 0; |
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} |
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/* |
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* Standard encapsulation |
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*/ |
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static int kiss_esc(unsigned char *s, unsigned char *d, int len) |
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{ |
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unsigned char *ptr = d; |
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unsigned char c; |
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/* |
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* Send an initial END character to flush out any data that may have |
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* accumulated in the receiver due to line noise. |
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*/ |
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*ptr++ = END; |
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while (len-- > 0) { |
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switch (c = *s++) { |
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case END: |
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*ptr++ = ESC; |
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*ptr++ = ESC_END; |
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break; |
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case ESC: |
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*ptr++ = ESC; |
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*ptr++ = ESC_ESC; |
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break; |
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default: |
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*ptr++ = c; |
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break; |
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} |
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} |
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*ptr++ = END; |
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return ptr - d; |
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} |
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/* |
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* MW: |
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* OK its ugly, but tell me a better solution without copying the |
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* packet to a temporary buffer :-) |
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*/ |
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static int kiss_esc_crc(unsigned char *s, unsigned char *d, unsigned short crc, |
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int len) |
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{ |
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unsigned char *ptr = d; |
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unsigned char c=0; |
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*ptr++ = END; |
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while (len > 0) { |
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if (len > 2) |
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c = *s++; |
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else if (len > 1) |
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c = crc >> 8; |
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else |
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c = crc & 0xff; |
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len--; |
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switch (c) { |
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case END: |
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*ptr++ = ESC; |
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*ptr++ = ESC_END; |
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break; |
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case ESC: |
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*ptr++ = ESC; |
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*ptr++ = ESC_ESC; |
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break; |
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default: |
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*ptr++ = c; |
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break; |
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} |
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} |
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*ptr++ = END; |
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return ptr - d; |
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} |
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/* Send one completely decapsulated AX.25 packet to the AX.25 layer. */ |
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static void ax_bump(struct mkiss *ax) |
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{ |
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struct sk_buff *skb; |
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int count; |
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spin_lock_bh(&ax->buflock); |
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if (ax->rbuff[0] > 0x0f) { |
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if (ax->rbuff[0] & 0x80) { |
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if (check_crc_16(ax->rbuff, ax->rcount) < 0) { |
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ax->dev->stats.rx_errors++; |
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spin_unlock_bh(&ax->buflock); |
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return; |
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} |
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if (ax->crcmode != CRC_MODE_SMACK && ax->crcauto) { |
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printk(KERN_INFO |
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"mkiss: %s: Switching to crc-smack\n", |
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ax->dev->name); |
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ax->crcmode = CRC_MODE_SMACK; |
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} |
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ax->rcount -= 2; |
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*ax->rbuff &= ~0x80; |
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} else if (ax->rbuff[0] & 0x20) { |
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if (check_crc_flex(ax->rbuff, ax->rcount) < 0) { |
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ax->dev->stats.rx_errors++; |
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spin_unlock_bh(&ax->buflock); |
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return; |
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} |
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if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) { |
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printk(KERN_INFO |
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"mkiss: %s: Switching to crc-flexnet\n", |
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ax->dev->name); |
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ax->crcmode = CRC_MODE_FLEX; |
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} |
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ax->rcount -= 2; |
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/* |
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* dl9sau bugfix: the trailling two bytes flexnet crc |
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* will not be passed to the kernel. thus we have to |
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* correct the kissparm signature, because it indicates |
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* a crc but there's none |
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*/ |
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*ax->rbuff &= ~0x20; |
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} |
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} |
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count = ax->rcount; |
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if ((skb = dev_alloc_skb(count)) == NULL) { |
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printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n", |
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ax->dev->name); |
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ax->dev->stats.rx_dropped++; |
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spin_unlock_bh(&ax->buflock); |
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return; |
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} |
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skb_put_data(skb, ax->rbuff, count); |
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skb->protocol = ax25_type_trans(skb, ax->dev); |
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netif_rx(skb); |
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ax->dev->stats.rx_packets++; |
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ax->dev->stats.rx_bytes += count; |
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spin_unlock_bh(&ax->buflock); |
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} |
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static void kiss_unesc(struct mkiss *ax, unsigned char s) |
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{ |
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switch (s) { |
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case END: |
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/* drop keeptest bit = VSV */ |
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if (test_bit(AXF_KEEPTEST, &ax->flags)) |
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clear_bit(AXF_KEEPTEST, &ax->flags); |
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if (!test_and_clear_bit(AXF_ERROR, &ax->flags) && (ax->rcount > 2)) |
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ax_bump(ax); |
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clear_bit(AXF_ESCAPE, &ax->flags); |
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ax->rcount = 0; |
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return; |
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case ESC: |
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set_bit(AXF_ESCAPE, &ax->flags); |
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return; |
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case ESC_ESC: |
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if (test_and_clear_bit(AXF_ESCAPE, &ax->flags)) |
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s = ESC; |
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break; |
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case ESC_END: |
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if (test_and_clear_bit(AXF_ESCAPE, &ax->flags)) |
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s = END; |
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break; |
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} |
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spin_lock_bh(&ax->buflock); |
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if (!test_bit(AXF_ERROR, &ax->flags)) { |
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if (ax->rcount < ax->buffsize) { |
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ax->rbuff[ax->rcount++] = s; |
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spin_unlock_bh(&ax->buflock); |
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return; |
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} |
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ax->dev->stats.rx_over_errors++; |
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set_bit(AXF_ERROR, &ax->flags); |
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} |
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spin_unlock_bh(&ax->buflock); |
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} |
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static int ax_set_mac_address(struct net_device *dev, void *addr) |
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{ |
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struct sockaddr_ax25 *sa = addr; |
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netif_tx_lock_bh(dev); |
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netif_addr_lock(dev); |
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memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN); |
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netif_addr_unlock(dev); |
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netif_tx_unlock_bh(dev); |
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return 0; |
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} |
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/*---------------------------------------------------------------------------*/ |
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static void ax_changedmtu(struct mkiss *ax) |
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{ |
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struct net_device *dev = ax->dev; |
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unsigned char *xbuff, *rbuff, *oxbuff, *orbuff; |
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int len; |
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len = dev->mtu * 2; |
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/* |
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* allow for arrival of larger UDP packets, even if we say not to |
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* also fixes a bug in which SunOS sends 512-byte packets even with |
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* an MSS of 128 |
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*/ |
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if (len < 576 * 2) |
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len = 576 * 2; |
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xbuff = kmalloc(len + 4, GFP_ATOMIC); |
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rbuff = kmalloc(len + 4, GFP_ATOMIC); |
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if (xbuff == NULL || rbuff == NULL) { |
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printk(KERN_ERR "mkiss: %s: unable to grow ax25 buffers, " |
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"MTU change cancelled.\n", |
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ax->dev->name); |
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dev->mtu = ax->mtu; |
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kfree(xbuff); |
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kfree(rbuff); |
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return; |
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} |
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spin_lock_bh(&ax->buflock); |
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oxbuff = ax->xbuff; |
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ax->xbuff = xbuff; |
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orbuff = ax->rbuff; |
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ax->rbuff = rbuff; |
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if (ax->xleft) { |
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if (ax->xleft <= len) { |
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memcpy(ax->xbuff, ax->xhead, ax->xleft); |
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} else { |
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ax->xleft = 0; |
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dev->stats.tx_dropped++; |
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} |
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} |
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ax->xhead = ax->xbuff; |
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if (ax->rcount) { |
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if (ax->rcount <= len) { |
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memcpy(ax->rbuff, orbuff, ax->rcount); |
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} else { |
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ax->rcount = 0; |
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dev->stats.rx_over_errors++; |
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set_bit(AXF_ERROR, &ax->flags); |
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} |
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} |
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ax->mtu = dev->mtu + 73; |
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ax->buffsize = len; |
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spin_unlock_bh(&ax->buflock); |
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kfree(oxbuff); |
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kfree(orbuff); |
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} |
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/* Encapsulate one AX.25 packet and stuff into a TTY queue. */ |
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static void ax_encaps(struct net_device *dev, unsigned char *icp, int len) |
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{ |
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struct mkiss *ax = netdev_priv(dev); |
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unsigned char *p; |
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int actual, count; |
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if (ax->mtu != ax->dev->mtu + 73) /* Someone has been ifconfigging */ |
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ax_changedmtu(ax); |
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if (len > ax->mtu) { /* Sigh, shouldn't occur BUT ... */ |
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printk(KERN_ERR "mkiss: %s: truncating oversized transmit packet!\n", ax->dev->name); |
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dev->stats.tx_dropped++; |
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netif_start_queue(dev); |
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return; |
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} |
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p = icp; |
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spin_lock_bh(&ax->buflock); |
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if ((*p & 0x0f) != 0) { |
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/* Configuration Command (kissparms(1). |
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* Protocol spec says: never append CRC. |
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* This fixes a very old bug in the linux |
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* kiss driver. -- dl9sau */ |
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switch (*p & 0xff) { |
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case 0x85: |
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/* command from userspace especially for us, |
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* not for delivery to the tnc */ |
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if (len > 1) { |
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int cmd = (p[1] & 0xff); |
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switch(cmd) { |
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case 3: |
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ax->crcmode = CRC_MODE_SMACK; |
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break; |
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case 2: |
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ax->crcmode = CRC_MODE_FLEX; |
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break; |
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case 1: |
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ax->crcmode = CRC_MODE_NONE; |
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break; |
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case 0: |
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default: |
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ax->crcmode = CRC_MODE_SMACK_TEST; |
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cmd = 0; |
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} |
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ax->crcauto = (cmd ? 0 : 1); |
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printk(KERN_INFO "mkiss: %s: crc mode set to %d\n", |
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ax->dev->name, cmd); |
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} |
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spin_unlock_bh(&ax->buflock); |
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netif_start_queue(dev); |
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|
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return; |
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default: |
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count = kiss_esc(p, ax->xbuff, len); |
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} |
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} else { |
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unsigned short crc; |
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switch (ax->crcmode) { |
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case CRC_MODE_SMACK_TEST: |
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ax->crcmode = CRC_MODE_FLEX_TEST; |
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printk(KERN_INFO "mkiss: %s: Trying crc-smack\n", ax->dev->name); |
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fallthrough; |
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case CRC_MODE_SMACK: |
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*p |= 0x80; |
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crc = swab16(crc16(0, p, len)); |
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count = kiss_esc_crc(p, ax->xbuff, crc, len+2); |
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break; |
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case CRC_MODE_FLEX_TEST: |
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ax->crcmode = CRC_MODE_NONE; |
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printk(KERN_INFO "mkiss: %s: Trying crc-flexnet\n", ax->dev->name); |
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fallthrough; |
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case CRC_MODE_FLEX: |
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*p |= 0x20; |
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crc = calc_crc_flex(p, len); |
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count = kiss_esc_crc(p, ax->xbuff, crc, len+2); |
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break; |
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|
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default: |
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count = kiss_esc(p, ax->xbuff, len); |
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} |
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} |
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spin_unlock_bh(&ax->buflock); |
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|
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set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); |
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actual = ax->tty->ops->write(ax->tty, ax->xbuff, count); |
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dev->stats.tx_packets++; |
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dev->stats.tx_bytes += actual; |
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|
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netif_trans_update(ax->dev); |
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ax->xleft = count - actual; |
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ax->xhead = ax->xbuff + actual; |
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} |
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|
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/* Encapsulate an AX.25 packet and kick it into a TTY queue. */ |
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static netdev_tx_t ax_xmit(struct sk_buff *skb, struct net_device *dev) |
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{ |
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struct mkiss *ax = netdev_priv(dev); |
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|
|
if (skb->protocol == htons(ETH_P_IP)) |
|
return ax25_ip_xmit(skb); |
|
|
|
if (!netif_running(dev)) { |
|
printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name); |
|
return NETDEV_TX_BUSY; |
|
} |
|
|
|
if (netif_queue_stopped(dev)) { |
|
/* |
|
* May be we must check transmitter timeout here ? |
|
* 14 Oct 1994 Dmitry Gorodchanin. |
|
*/ |
|
if (time_before(jiffies, dev_trans_start(dev) + 20 * HZ)) { |
|
/* 20 sec timeout not reached */ |
|
return NETDEV_TX_BUSY; |
|
} |
|
|
|
printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name, |
|
(tty_chars_in_buffer(ax->tty) || ax->xleft) ? |
|
"bad line quality" : "driver error"); |
|
|
|
ax->xleft = 0; |
|
clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); |
|
netif_start_queue(dev); |
|
} |
|
|
|
/* We were not busy, so we are now... :-) */ |
|
netif_stop_queue(dev); |
|
ax_encaps(dev, skb->data, skb->len); |
|
kfree_skb(skb); |
|
|
|
return NETDEV_TX_OK; |
|
} |
|
|
|
static int ax_open_dev(struct net_device *dev) |
|
{ |
|
struct mkiss *ax = netdev_priv(dev); |
|
|
|
if (ax->tty == NULL) |
|
return -ENODEV; |
|
|
|
return 0; |
|
} |
|
|
|
/* Open the low-level part of the AX25 channel. Easy! */ |
|
static int ax_open(struct net_device *dev) |
|
{ |
|
struct mkiss *ax = netdev_priv(dev); |
|
unsigned long len; |
|
|
|
if (ax->tty == NULL) |
|
return -ENODEV; |
|
|
|
/* |
|
* Allocate the frame buffers: |
|
* |
|
* rbuff Receive buffer. |
|
* xbuff Transmit buffer. |
|
*/ |
|
len = dev->mtu * 2; |
|
|
|
/* |
|
* allow for arrival of larger UDP packets, even if we say not to |
|
* also fixes a bug in which SunOS sends 512-byte packets even with |
|
* an MSS of 128 |
|
*/ |
|
if (len < 576 * 2) |
|
len = 576 * 2; |
|
|
|
if ((ax->rbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL) |
|
goto norbuff; |
|
|
|
if ((ax->xbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL) |
|
goto noxbuff; |
|
|
|
ax->mtu = dev->mtu + 73; |
|
ax->buffsize = len; |
|
ax->rcount = 0; |
|
ax->xleft = 0; |
|
|
|
ax->flags &= (1 << AXF_INUSE); /* Clear ESCAPE & ERROR flags */ |
|
|
|
spin_lock_init(&ax->buflock); |
|
|
|
return 0; |
|
|
|
noxbuff: |
|
kfree(ax->rbuff); |
|
|
|
norbuff: |
|
return -ENOMEM; |
|
} |
|
|
|
|
|
/* Close the low-level part of the AX25 channel. Easy! */ |
|
static int ax_close(struct net_device *dev) |
|
{ |
|
struct mkiss *ax = netdev_priv(dev); |
|
|
|
if (ax->tty) |
|
clear_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags); |
|
|
|
netif_stop_queue(dev); |
|
|
|
return 0; |
|
} |
|
|
|
static const struct net_device_ops ax_netdev_ops = { |
|
.ndo_open = ax_open_dev, |
|
.ndo_stop = ax_close, |
|
.ndo_start_xmit = ax_xmit, |
|
.ndo_set_mac_address = ax_set_mac_address, |
|
}; |
|
|
|
static void ax_setup(struct net_device *dev) |
|
{ |
|
/* Finish setting up the DEVICE info. */ |
|
dev->mtu = AX_MTU; |
|
dev->hard_header_len = AX25_MAX_HEADER_LEN; |
|
dev->addr_len = AX25_ADDR_LEN; |
|
dev->type = ARPHRD_AX25; |
|
dev->tx_queue_len = 10; |
|
dev->header_ops = &ax25_header_ops; |
|
dev->netdev_ops = &ax_netdev_ops; |
|
|
|
|
|
memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); |
|
memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); |
|
|
|
dev->flags = IFF_BROADCAST | IFF_MULTICAST; |
|
} |
|
|
|
/* |
|
* We have a potential race on dereferencing tty->disc_data, because the tty |
|
* layer provides no locking at all - thus one cpu could be running |
|
* sixpack_receive_buf while another calls sixpack_close, which zeroes |
|
* tty->disc_data and frees the memory that sixpack_receive_buf is using. The |
|
* best way to fix this is to use a rwlock in the tty struct, but for now we |
|
* use a single global rwlock for all ttys in ppp line discipline. |
|
*/ |
|
static DEFINE_RWLOCK(disc_data_lock); |
|
|
|
static struct mkiss *mkiss_get(struct tty_struct *tty) |
|
{ |
|
struct mkiss *ax; |
|
|
|
read_lock(&disc_data_lock); |
|
ax = tty->disc_data; |
|
if (ax) |
|
refcount_inc(&ax->refcnt); |
|
read_unlock(&disc_data_lock); |
|
|
|
return ax; |
|
} |
|
|
|
static void mkiss_put(struct mkiss *ax) |
|
{ |
|
if (refcount_dec_and_test(&ax->refcnt)) |
|
complete(&ax->dead); |
|
} |
|
|
|
static int crc_force = 0; /* Can be overridden with insmod */ |
|
|
|
static int mkiss_open(struct tty_struct *tty) |
|
{ |
|
struct net_device *dev; |
|
struct mkiss *ax; |
|
int err; |
|
|
|
if (!capable(CAP_NET_ADMIN)) |
|
return -EPERM; |
|
if (tty->ops->write == NULL) |
|
return -EOPNOTSUPP; |
|
|
|
dev = alloc_netdev(sizeof(struct mkiss), "ax%d", NET_NAME_UNKNOWN, |
|
ax_setup); |
|
if (!dev) { |
|
err = -ENOMEM; |
|
goto out; |
|
} |
|
|
|
ax = netdev_priv(dev); |
|
ax->dev = dev; |
|
|
|
spin_lock_init(&ax->buflock); |
|
refcount_set(&ax->refcnt, 1); |
|
init_completion(&ax->dead); |
|
|
|
ax->tty = tty; |
|
tty->disc_data = ax; |
|
tty->receive_room = 65535; |
|
|
|
tty_driver_flush_buffer(tty); |
|
|
|
/* Restore default settings */ |
|
dev->type = ARPHRD_AX25; |
|
|
|
/* Perform the low-level AX25 initialization. */ |
|
err = ax_open(ax->dev); |
|
if (err) |
|
goto out_free_netdev; |
|
|
|
err = register_netdev(dev); |
|
if (err) |
|
goto out_free_buffers; |
|
|
|
/* after register_netdev() - because else printk smashes the kernel */ |
|
switch (crc_force) { |
|
case 3: |
|
ax->crcmode = CRC_MODE_SMACK; |
|
printk(KERN_INFO "mkiss: %s: crc mode smack forced.\n", |
|
ax->dev->name); |
|
break; |
|
case 2: |
|
ax->crcmode = CRC_MODE_FLEX; |
|
printk(KERN_INFO "mkiss: %s: crc mode flexnet forced.\n", |
|
ax->dev->name); |
|
break; |
|
case 1: |
|
ax->crcmode = CRC_MODE_NONE; |
|
printk(KERN_INFO "mkiss: %s: crc mode disabled.\n", |
|
ax->dev->name); |
|
break; |
|
case 0: |
|
default: |
|
crc_force = 0; |
|
printk(KERN_INFO "mkiss: %s: crc mode is auto.\n", |
|
ax->dev->name); |
|
ax->crcmode = CRC_MODE_SMACK_TEST; |
|
} |
|
ax->crcauto = (crc_force ? 0 : 1); |
|
|
|
netif_start_queue(dev); |
|
|
|
/* Done. We have linked the TTY line to a channel. */ |
|
return 0; |
|
|
|
out_free_buffers: |
|
kfree(ax->rbuff); |
|
kfree(ax->xbuff); |
|
|
|
out_free_netdev: |
|
free_netdev(dev); |
|
|
|
out: |
|
return err; |
|
} |
|
|
|
static void mkiss_close(struct tty_struct *tty) |
|
{ |
|
struct mkiss *ax; |
|
|
|
write_lock_irq(&disc_data_lock); |
|
ax = tty->disc_data; |
|
tty->disc_data = NULL; |
|
write_unlock_irq(&disc_data_lock); |
|
|
|
if (!ax) |
|
return; |
|
|
|
/* |
|
* We have now ensured that nobody can start using ap from now on, but |
|
* we have to wait for all existing users to finish. |
|
*/ |
|
if (!refcount_dec_and_test(&ax->refcnt)) |
|
wait_for_completion(&ax->dead); |
|
/* |
|
* Halt the transmit queue so that a new transmit cannot scribble |
|
* on our buffers |
|
*/ |
|
netif_stop_queue(ax->dev); |
|
|
|
/* Free all AX25 frame buffers. */ |
|
kfree(ax->rbuff); |
|
kfree(ax->xbuff); |
|
|
|
ax->tty = NULL; |
|
|
|
unregister_netdev(ax->dev); |
|
} |
|
|
|
/* Perform I/O control on an active ax25 channel. */ |
|
static int mkiss_ioctl(struct tty_struct *tty, struct file *file, |
|
unsigned int cmd, unsigned long arg) |
|
{ |
|
struct mkiss *ax = mkiss_get(tty); |
|
struct net_device *dev; |
|
unsigned int tmp, err; |
|
|
|
/* First make sure we're connected. */ |
|
if (ax == NULL) |
|
return -ENXIO; |
|
dev = ax->dev; |
|
|
|
switch (cmd) { |
|
case SIOCGIFNAME: |
|
err = copy_to_user((void __user *) arg, ax->dev->name, |
|
strlen(ax->dev->name) + 1) ? -EFAULT : 0; |
|
break; |
|
|
|
case SIOCGIFENCAP: |
|
err = put_user(4, (int __user *) arg); |
|
break; |
|
|
|
case SIOCSIFENCAP: |
|
if (get_user(tmp, (int __user *) arg)) { |
|
err = -EFAULT; |
|
break; |
|
} |
|
|
|
ax->mode = tmp; |
|
dev->addr_len = AX25_ADDR_LEN; |
|
dev->hard_header_len = AX25_KISS_HEADER_LEN + |
|
AX25_MAX_HEADER_LEN + 3; |
|
dev->type = ARPHRD_AX25; |
|
|
|
err = 0; |
|
break; |
|
|
|
case SIOCSIFHWADDR: { |
|
char addr[AX25_ADDR_LEN]; |
|
|
|
if (copy_from_user(&addr, |
|
(void __user *) arg, AX25_ADDR_LEN)) { |
|
err = -EFAULT; |
|
break; |
|
} |
|
|
|
netif_tx_lock_bh(dev); |
|
memcpy(dev->dev_addr, addr, AX25_ADDR_LEN); |
|
netif_tx_unlock_bh(dev); |
|
|
|
err = 0; |
|
break; |
|
} |
|
default: |
|
err = -ENOIOCTLCMD; |
|
} |
|
|
|
mkiss_put(ax); |
|
|
|
return err; |
|
} |
|
|
|
/* |
|
* Handle the 'receiver data ready' interrupt. |
|
* This function is called by the 'tty_io' module in the kernel when |
|
* a block of data has been received, which can now be decapsulated |
|
* and sent on to the AX.25 layer for further processing. |
|
*/ |
|
static void mkiss_receive_buf(struct tty_struct *tty, const unsigned char *cp, |
|
char *fp, int count) |
|
{ |
|
struct mkiss *ax = mkiss_get(tty); |
|
|
|
if (!ax) |
|
return; |
|
|
|
/* |
|
* Argh! mtu change time! - costs us the packet part received |
|
* at the change |
|
*/ |
|
if (ax->mtu != ax->dev->mtu + 73) |
|
ax_changedmtu(ax); |
|
|
|
/* Read the characters out of the buffer */ |
|
while (count--) { |
|
if (fp != NULL && *fp++) { |
|
if (!test_and_set_bit(AXF_ERROR, &ax->flags)) |
|
ax->dev->stats.rx_errors++; |
|
cp++; |
|
continue; |
|
} |
|
|
|
kiss_unesc(ax, *cp++); |
|
} |
|
|
|
mkiss_put(ax); |
|
tty_unthrottle(tty); |
|
} |
|
|
|
/* |
|
* Called by the driver when there's room for more data. If we have |
|
* more packets to send, we send them here. |
|
*/ |
|
static void mkiss_write_wakeup(struct tty_struct *tty) |
|
{ |
|
struct mkiss *ax = mkiss_get(tty); |
|
int actual; |
|
|
|
if (!ax) |
|
return; |
|
|
|
if (ax->xleft <= 0) { |
|
/* Now serial buffer is almost free & we can start |
|
* transmission of another packet |
|
*/ |
|
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
|
|
|
netif_wake_queue(ax->dev); |
|
goto out; |
|
} |
|
|
|
actual = tty->ops->write(tty, ax->xhead, ax->xleft); |
|
ax->xleft -= actual; |
|
ax->xhead += actual; |
|
|
|
out: |
|
mkiss_put(ax); |
|
} |
|
|
|
static struct tty_ldisc_ops ax_ldisc = { |
|
.owner = THIS_MODULE, |
|
.magic = TTY_LDISC_MAGIC, |
|
.name = "mkiss", |
|
.open = mkiss_open, |
|
.close = mkiss_close, |
|
.ioctl = mkiss_ioctl, |
|
.receive_buf = mkiss_receive_buf, |
|
.write_wakeup = mkiss_write_wakeup |
|
}; |
|
|
|
static const char banner[] __initconst = KERN_INFO \ |
|
"mkiss: AX.25 Multikiss, Hans Albas PE1AYX\n"; |
|
static const char msg_regfail[] __initconst = KERN_ERR \ |
|
"mkiss: can't register line discipline (err = %d)\n"; |
|
|
|
static int __init mkiss_init_driver(void) |
|
{ |
|
int status; |
|
|
|
printk(banner); |
|
|
|
status = tty_register_ldisc(N_AX25, &ax_ldisc); |
|
if (status != 0) |
|
printk(msg_regfail, status); |
|
|
|
return status; |
|
} |
|
|
|
static const char msg_unregfail[] = KERN_ERR \ |
|
"mkiss: can't unregister line discipline (err = %d)\n"; |
|
|
|
static void __exit mkiss_exit_driver(void) |
|
{ |
|
int ret; |
|
|
|
if ((ret = tty_unregister_ldisc(N_AX25))) |
|
printk(msg_unregfail, ret); |
|
} |
|
|
|
MODULE_AUTHOR("Ralf Baechle DL5RB <[email protected]>"); |
|
MODULE_DESCRIPTION("KISS driver for AX.25 over TTYs"); |
|
module_param(crc_force, int, 0); |
|
MODULE_PARM_DESC(crc_force, "crc [0 = auto | 1 = none | 2 = flexnet | 3 = smack]"); |
|
MODULE_LICENSE("GPL"); |
|
MODULE_ALIAS_LDISC(N_AX25); |
|
|
|
module_init(mkiss_init_driver); |
|
module_exit(mkiss_exit_driver);
|
|
|