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755 lines
19 KiB
755 lines
19 KiB
/* |
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* Routines to compress and uncompress tcp packets (for transmission |
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* over low speed serial lines). |
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* |
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* Copyright (c) 1989 Regents of the University of California. |
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* All rights reserved. |
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* |
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* Redistribution and use in source and binary forms are permitted |
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* provided that the above copyright notice and this paragraph are |
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* duplicated in all such forms and that any documentation, |
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* advertising materials, and other materials related to such |
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* distribution and use acknowledge that the software was developed |
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* by the University of California, Berkeley. The name of the |
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* University may not be used to endorse or promote products derived |
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* from this software without specific prior written permission. |
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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* |
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* Van Jacobson ([email protected]), Dec 31, 1989: |
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* - Initial distribution. |
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* |
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* |
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* modified for KA9Q Internet Software Package by |
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* Katie Stevens ([email protected]) |
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* University of California, Davis |
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* Computing Services |
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* - 01-31-90 initial adaptation (from 1.19) |
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* PPP.05 02-15-90 [ks] |
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* PPP.08 05-02-90 [ks] use PPP protocol field to signal compression |
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* PPP.15 09-90 [ks] improve mbuf handling |
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* PPP.16 11-02 [karn] substantially rewritten to use NOS facilities |
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* |
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* - Feb 1991 [email protected] |
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* variable number of conversation slots |
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* allow zero or one slots |
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* separate routines |
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* status display |
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* - Jul 1994 Dmitry Gorodchanin |
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* Fixes for memory leaks. |
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* - Oct 1994 Dmitry Gorodchanin |
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* Modularization. |
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* - Jan 1995 Bjorn Ekwall |
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* Use ip_fast_csum from ip.h |
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* - July 1995 Christos A. Polyzols |
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* Spotted bug in tcp option checking |
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* |
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* |
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* This module is a difficult issue. It's clearly inet code but it's also clearly |
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* driver code belonging close to PPP and SLIP |
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*/ |
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|
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/types.h> |
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#include <linux/string.h> |
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#include <linux/errno.h> |
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#include <linux/kernel.h> |
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#include <net/slhc_vj.h> |
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|
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#ifdef CONFIG_INET |
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/* Entire module is for IP only */ |
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#include <linux/mm.h> |
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#include <linux/socket.h> |
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#include <linux/sockios.h> |
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#include <linux/termios.h> |
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#include <linux/in.h> |
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#include <linux/fcntl.h> |
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#include <linux/inet.h> |
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#include <linux/netdevice.h> |
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#include <net/ip.h> |
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#include <net/protocol.h> |
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#include <net/icmp.h> |
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#include <net/tcp.h> |
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#include <linux/skbuff.h> |
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#include <net/sock.h> |
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#include <linux/timer.h> |
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#include <linux/uaccess.h> |
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#include <net/checksum.h> |
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#include <asm/unaligned.h> |
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|
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static unsigned char *encode(unsigned char *cp, unsigned short n); |
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static long decode(unsigned char **cpp); |
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static unsigned char * put16(unsigned char *cp, unsigned short x); |
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static unsigned short pull16(unsigned char **cpp); |
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|
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/* Allocate compression data structure |
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* slots must be in range 0 to 255 (zero meaning no compression) |
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* Returns pointer to structure or ERR_PTR() on error. |
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*/ |
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struct slcompress * |
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slhc_init(int rslots, int tslots) |
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{ |
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short i; |
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struct cstate *ts; |
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struct slcompress *comp; |
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|
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if (rslots < 0 || rslots > 255 || tslots < 0 || tslots > 255) |
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return ERR_PTR(-EINVAL); |
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|
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comp = kzalloc(sizeof(struct slcompress), GFP_KERNEL); |
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if (! comp) |
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goto out_fail; |
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|
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if (rslots > 0) { |
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size_t rsize = rslots * sizeof(struct cstate); |
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comp->rstate = kzalloc(rsize, GFP_KERNEL); |
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if (! comp->rstate) |
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goto out_free; |
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comp->rslot_limit = rslots - 1; |
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} |
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|
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if (tslots > 0) { |
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size_t tsize = tslots * sizeof(struct cstate); |
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comp->tstate = kzalloc(tsize, GFP_KERNEL); |
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if (! comp->tstate) |
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goto out_free2; |
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comp->tslot_limit = tslots - 1; |
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} |
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|
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comp->xmit_oldest = 0; |
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comp->xmit_current = 255; |
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comp->recv_current = 255; |
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/* |
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* don't accept any packets with implicit index until we get |
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* one with an explicit index. Otherwise the uncompress code |
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* will try to use connection 255, which is almost certainly |
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* out of range |
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*/ |
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comp->flags |= SLF_TOSS; |
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|
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if ( tslots > 0 ) { |
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ts = comp->tstate; |
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for(i = comp->tslot_limit; i > 0; --i){ |
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ts[i].cs_this = i; |
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ts[i].next = &(ts[i - 1]); |
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} |
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ts[0].next = &(ts[comp->tslot_limit]); |
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ts[0].cs_this = 0; |
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} |
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return comp; |
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|
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out_free2: |
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kfree(comp->rstate); |
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out_free: |
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kfree(comp); |
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out_fail: |
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return ERR_PTR(-ENOMEM); |
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} |
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|
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|
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/* Free a compression data structure */ |
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void |
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slhc_free(struct slcompress *comp) |
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{ |
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if ( IS_ERR_OR_NULL(comp) ) |
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return; |
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|
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if ( comp->tstate != NULLSLSTATE ) |
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kfree( comp->tstate ); |
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|
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if ( comp->rstate != NULLSLSTATE ) |
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kfree( comp->rstate ); |
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|
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kfree( comp ); |
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} |
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|
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|
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/* Put a short in host order into a char array in network order */ |
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static inline unsigned char * |
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put16(unsigned char *cp, unsigned short x) |
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{ |
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*cp++ = x >> 8; |
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*cp++ = x; |
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|
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return cp; |
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} |
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|
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/* Encode a number */ |
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static unsigned char * |
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encode(unsigned char *cp, unsigned short n) |
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{ |
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if(n >= 256 || n == 0){ |
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*cp++ = 0; |
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cp = put16(cp,n); |
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} else { |
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*cp++ = n; |
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} |
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return cp; |
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} |
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|
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/* Pull a 16-bit integer in host order from buffer in network byte order */ |
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static unsigned short |
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pull16(unsigned char **cpp) |
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{ |
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short rval; |
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|
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rval = *(*cpp)++; |
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rval <<= 8; |
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rval |= *(*cpp)++; |
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return rval; |
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} |
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|
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/* Decode a number */ |
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static long |
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decode(unsigned char **cpp) |
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{ |
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int x; |
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|
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x = *(*cpp)++; |
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if(x == 0){ |
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return pull16(cpp) & 0xffff; /* pull16 returns -1 on error */ |
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} else { |
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return x & 0xff; /* -1 if PULLCHAR returned error */ |
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} |
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} |
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/* |
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* icp and isize are the original packet. |
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* ocp is a place to put a copy if necessary. |
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* cpp is initially a pointer to icp. If the copy is used, |
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* change it to ocp. |
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*/ |
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|
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int |
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slhc_compress(struct slcompress *comp, unsigned char *icp, int isize, |
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unsigned char *ocp, unsigned char **cpp, int compress_cid) |
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{ |
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struct cstate *ocs = &(comp->tstate[comp->xmit_oldest]); |
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struct cstate *lcs = ocs; |
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struct cstate *cs = lcs->next; |
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unsigned long deltaS, deltaA; |
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short changes = 0; |
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int nlen, hlen; |
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unsigned char new_seq[16]; |
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unsigned char *cp = new_seq; |
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struct iphdr *ip; |
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struct tcphdr *th, *oth; |
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__sum16 csum; |
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|
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/* |
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* Don't play with runt packets. |
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*/ |
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|
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if(isize<sizeof(struct iphdr)) |
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return isize; |
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|
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ip = (struct iphdr *) icp; |
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if (ip->version != 4 || ip->ihl < 5) |
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return isize; |
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|
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/* Bail if this packet isn't TCP, or is an IP fragment */ |
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if (ip->protocol != IPPROTO_TCP || (ntohs(ip->frag_off) & 0x3fff)) { |
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/* Send as regular IP */ |
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if(ip->protocol != IPPROTO_TCP) |
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comp->sls_o_nontcp++; |
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else |
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comp->sls_o_tcp++; |
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return isize; |
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} |
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nlen = ip->ihl * 4; |
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if (isize < nlen + sizeof(*th)) |
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return isize; |
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|
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th = (struct tcphdr *)(icp + nlen); |
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if (th->doff < sizeof(struct tcphdr) / 4) |
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return isize; |
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hlen = nlen + th->doff * 4; |
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|
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/* Bail if the TCP packet isn't `compressible' (i.e., ACK isn't set or |
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* some other control bit is set). Also uncompressible if |
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* it's a runt. |
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*/ |
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if(hlen > isize || th->syn || th->fin || th->rst || |
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! (th->ack)){ |
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/* TCP connection stuff; send as regular IP */ |
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comp->sls_o_tcp++; |
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return isize; |
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} |
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/* |
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* Packet is compressible -- we're going to send either a |
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* COMPRESSED_TCP or UNCOMPRESSED_TCP packet. Either way, |
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* we need to locate (or create) the connection state. |
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* |
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* States are kept in a circularly linked list with |
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* xmit_oldest pointing to the end of the list. The |
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* list is kept in lru order by moving a state to the |
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* head of the list whenever it is referenced. Since |
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* the list is short and, empirically, the connection |
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* we want is almost always near the front, we locate |
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* states via linear search. If we don't find a state |
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* for the datagram, the oldest state is (re-)used. |
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*/ |
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for ( ; ; ) { |
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if( ip->saddr == cs->cs_ip.saddr |
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&& ip->daddr == cs->cs_ip.daddr |
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&& th->source == cs->cs_tcp.source |
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&& th->dest == cs->cs_tcp.dest) |
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goto found; |
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/* if current equal oldest, at end of list */ |
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if ( cs == ocs ) |
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break; |
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lcs = cs; |
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cs = cs->next; |
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comp->sls_o_searches++; |
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} |
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/* |
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* Didn't find it -- re-use oldest cstate. Send an |
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* uncompressed packet that tells the other side what |
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* connection number we're using for this conversation. |
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* |
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* Note that since the state list is circular, the oldest |
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* state points to the newest and we only need to set |
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* xmit_oldest to update the lru linkage. |
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*/ |
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comp->sls_o_misses++; |
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comp->xmit_oldest = lcs->cs_this; |
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goto uncompressed; |
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found: |
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/* |
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* Found it -- move to the front on the connection list. |
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*/ |
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if(lcs == ocs) { |
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/* found at most recently used */ |
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} else if (cs == ocs) { |
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/* found at least recently used */ |
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comp->xmit_oldest = lcs->cs_this; |
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} else { |
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/* more than 2 elements */ |
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lcs->next = cs->next; |
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cs->next = ocs->next; |
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ocs->next = cs; |
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} |
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|
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/* |
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* Make sure that only what we expect to change changed. |
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* Check the following: |
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* IP protocol version, header length & type of service. |
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* The "Don't fragment" bit. |
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* The time-to-live field. |
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* The TCP header length. |
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* IP options, if any. |
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* TCP options, if any. |
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* If any of these things are different between the previous & |
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* current datagram, we send the current datagram `uncompressed'. |
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*/ |
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oth = &cs->cs_tcp; |
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|
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if(ip->version != cs->cs_ip.version || ip->ihl != cs->cs_ip.ihl |
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|| ip->tos != cs->cs_ip.tos |
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|| (ip->frag_off & htons(0x4000)) != (cs->cs_ip.frag_off & htons(0x4000)) |
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|| ip->ttl != cs->cs_ip.ttl |
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|| th->doff != cs->cs_tcp.doff |
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|| (ip->ihl > 5 && memcmp(ip+1,cs->cs_ipopt,((ip->ihl)-5)*4) != 0) |
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|| (th->doff > 5 && memcmp(th+1,cs->cs_tcpopt,((th->doff)-5)*4) != 0)){ |
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goto uncompressed; |
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} |
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|
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/* |
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* Figure out which of the changing fields changed. The |
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* receiver expects changes in the order: urgent, window, |
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* ack, seq (the order minimizes the number of temporaries |
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* needed in this section of code). |
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*/ |
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if(th->urg){ |
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deltaS = ntohs(th->urg_ptr); |
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cp = encode(cp,deltaS); |
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changes |= NEW_U; |
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} else if(th->urg_ptr != oth->urg_ptr){ |
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/* argh! URG not set but urp changed -- a sensible |
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* implementation should never do this but RFC793 |
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* doesn't prohibit the change so we have to deal |
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* with it. */ |
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goto uncompressed; |
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} |
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if((deltaS = ntohs(th->window) - ntohs(oth->window)) != 0){ |
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cp = encode(cp,deltaS); |
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changes |= NEW_W; |
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} |
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if((deltaA = ntohl(th->ack_seq) - ntohl(oth->ack_seq)) != 0L){ |
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if(deltaA > 0x0000ffff) |
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goto uncompressed; |
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cp = encode(cp,deltaA); |
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changes |= NEW_A; |
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} |
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if((deltaS = ntohl(th->seq) - ntohl(oth->seq)) != 0L){ |
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if(deltaS > 0x0000ffff) |
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goto uncompressed; |
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cp = encode(cp,deltaS); |
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changes |= NEW_S; |
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} |
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|
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switch(changes){ |
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case 0: /* Nothing changed. If this packet contains data and the |
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* last one didn't, this is probably a data packet following |
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* an ack (normal on an interactive connection) and we send |
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* it compressed. Otherwise it's probably a retransmit, |
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* retransmitted ack or window probe. Send it uncompressed |
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* in case the other side missed the compressed version. |
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*/ |
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if(ip->tot_len != cs->cs_ip.tot_len && |
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ntohs(cs->cs_ip.tot_len) == hlen) |
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break; |
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goto uncompressed; |
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case SPECIAL_I: |
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case SPECIAL_D: |
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/* actual changes match one of our special case encodings -- |
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* send packet uncompressed. |
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*/ |
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goto uncompressed; |
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case NEW_S|NEW_A: |
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if(deltaS == deltaA && |
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deltaS == ntohs(cs->cs_ip.tot_len) - hlen){ |
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/* special case for echoed terminal traffic */ |
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changes = SPECIAL_I; |
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cp = new_seq; |
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} |
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break; |
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case NEW_S: |
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if(deltaS == ntohs(cs->cs_ip.tot_len) - hlen){ |
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/* special case for data xfer */ |
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changes = SPECIAL_D; |
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cp = new_seq; |
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} |
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break; |
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} |
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deltaS = ntohs(ip->id) - ntohs(cs->cs_ip.id); |
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if(deltaS != 1){ |
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cp = encode(cp,deltaS); |
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changes |= NEW_I; |
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} |
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if(th->psh) |
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changes |= TCP_PUSH_BIT; |
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/* Grab the cksum before we overwrite it below. Then update our |
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* state with this packet's header. |
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*/ |
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csum = th->check; |
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memcpy(&cs->cs_ip,ip,20); |
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memcpy(&cs->cs_tcp,th,20); |
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/* We want to use the original packet as our compressed packet. |
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* (cp - new_seq) is the number of bytes we need for compressed |
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* sequence numbers. In addition we need one byte for the change |
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* mask, one for the connection id and two for the tcp checksum. |
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* So, (cp - new_seq) + 4 bytes of header are needed. |
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*/ |
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deltaS = cp - new_seq; |
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if(compress_cid == 0 || comp->xmit_current != cs->cs_this){ |
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cp = ocp; |
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*cpp = ocp; |
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*cp++ = changes | NEW_C; |
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*cp++ = cs->cs_this; |
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comp->xmit_current = cs->cs_this; |
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} else { |
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cp = ocp; |
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*cpp = ocp; |
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*cp++ = changes; |
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} |
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*(__sum16 *)cp = csum; |
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cp += 2; |
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/* deltaS is now the size of the change section of the compressed header */ |
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memcpy(cp,new_seq,deltaS); /* Write list of deltas */ |
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memcpy(cp+deltaS,icp+hlen,isize-hlen); |
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comp->sls_o_compressed++; |
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ocp[0] |= SL_TYPE_COMPRESSED_TCP; |
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return isize - hlen + deltaS + (cp - ocp); |
|
|
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/* Update connection state cs & send uncompressed packet (i.e., |
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* a regular ip/tcp packet but with the 'conversation id' we hope |
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* to use on future compressed packets in the protocol field). |
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*/ |
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uncompressed: |
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memcpy(&cs->cs_ip,ip,20); |
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memcpy(&cs->cs_tcp,th,20); |
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if (ip->ihl > 5) |
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memcpy(cs->cs_ipopt, ip+1, ((ip->ihl) - 5) * 4); |
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if (th->doff > 5) |
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memcpy(cs->cs_tcpopt, th+1, ((th->doff) - 5) * 4); |
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comp->xmit_current = cs->cs_this; |
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comp->sls_o_uncompressed++; |
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memcpy(ocp, icp, isize); |
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*cpp = ocp; |
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ocp[9] = cs->cs_this; |
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ocp[0] |= SL_TYPE_UNCOMPRESSED_TCP; |
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return isize; |
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} |
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|
|
|
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int |
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slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize) |
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{ |
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int changes; |
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long x; |
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struct tcphdr *thp; |
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struct iphdr *ip; |
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struct cstate *cs; |
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int len, hdrlen; |
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unsigned char *cp = icp; |
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|
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/* We've got a compressed packet; read the change byte */ |
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comp->sls_i_compressed++; |
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if(isize < 3){ |
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comp->sls_i_error++; |
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return 0; |
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} |
|
changes = *cp++; |
|
if(changes & NEW_C){ |
|
/* Make sure the state index is in range, then grab the state. |
|
* If we have a good state index, clear the 'discard' flag. |
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*/ |
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x = *cp++; /* Read conn index */ |
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if(x < 0 || x > comp->rslot_limit) |
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goto bad; |
|
|
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/* Check if the cstate is initialized */ |
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if (!comp->rstate[x].initialized) |
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goto bad; |
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|
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comp->flags &=~ SLF_TOSS; |
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comp->recv_current = x; |
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} else { |
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/* this packet has an implicit state index. If we've |
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* had a line error since the last time we got an |
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* explicit state index, we have to toss the packet. */ |
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if(comp->flags & SLF_TOSS){ |
|
comp->sls_i_tossed++; |
|
return 0; |
|
} |
|
} |
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cs = &comp->rstate[comp->recv_current]; |
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thp = &cs->cs_tcp; |
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ip = &cs->cs_ip; |
|
|
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thp->check = *(__sum16 *)cp; |
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cp += 2; |
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|
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thp->psh = (changes & TCP_PUSH_BIT) ? 1 : 0; |
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/* |
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* we can use the same number for the length of the saved header and |
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* the current one, because the packet wouldn't have been sent |
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* as compressed unless the options were the same as the previous one |
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*/ |
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|
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hdrlen = ip->ihl * 4 + thp->doff * 4; |
|
|
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switch(changes & SPECIALS_MASK){ |
|
case SPECIAL_I: /* Echoed terminal traffic */ |
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{ |
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short i; |
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i = ntohs(ip->tot_len) - hdrlen; |
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thp->ack_seq = htonl( ntohl(thp->ack_seq) + i); |
|
thp->seq = htonl( ntohl(thp->seq) + i); |
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} |
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break; |
|
|
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case SPECIAL_D: /* Unidirectional data */ |
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thp->seq = htonl( ntohl(thp->seq) + |
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ntohs(ip->tot_len) - hdrlen); |
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break; |
|
|
|
default: |
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if(changes & NEW_U){ |
|
thp->urg = 1; |
|
if((x = decode(&cp)) == -1) { |
|
goto bad; |
|
} |
|
thp->urg_ptr = htons(x); |
|
} else |
|
thp->urg = 0; |
|
if(changes & NEW_W){ |
|
if((x = decode(&cp)) == -1) { |
|
goto bad; |
|
} |
|
thp->window = htons( ntohs(thp->window) + x); |
|
} |
|
if(changes & NEW_A){ |
|
if((x = decode(&cp)) == -1) { |
|
goto bad; |
|
} |
|
thp->ack_seq = htonl( ntohl(thp->ack_seq) + x); |
|
} |
|
if(changes & NEW_S){ |
|
if((x = decode(&cp)) == -1) { |
|
goto bad; |
|
} |
|
thp->seq = htonl( ntohl(thp->seq) + x); |
|
} |
|
break; |
|
} |
|
if(changes & NEW_I){ |
|
if((x = decode(&cp)) == -1) { |
|
goto bad; |
|
} |
|
ip->id = htons (ntohs (ip->id) + x); |
|
} else |
|
ip->id = htons (ntohs (ip->id) + 1); |
|
|
|
/* |
|
* At this point, cp points to the first byte of data in the |
|
* packet. Put the reconstructed TCP and IP headers back on the |
|
* packet. Recalculate IP checksum (but not TCP checksum). |
|
*/ |
|
|
|
len = isize - (cp - icp); |
|
if (len < 0) |
|
goto bad; |
|
len += hdrlen; |
|
ip->tot_len = htons(len); |
|
ip->check = 0; |
|
|
|
memmove(icp + hdrlen, cp, len - hdrlen); |
|
|
|
cp = icp; |
|
memcpy(cp, ip, 20); |
|
cp += 20; |
|
|
|
if (ip->ihl > 5) { |
|
memcpy(cp, cs->cs_ipopt, (ip->ihl - 5) * 4); |
|
cp += (ip->ihl - 5) * 4; |
|
} |
|
|
|
put_unaligned(ip_fast_csum(icp, ip->ihl), |
|
&((struct iphdr *)icp)->check); |
|
|
|
memcpy(cp, thp, 20); |
|
cp += 20; |
|
|
|
if (thp->doff > 5) { |
|
memcpy(cp, cs->cs_tcpopt, ((thp->doff) - 5) * 4); |
|
cp += ((thp->doff) - 5) * 4; |
|
} |
|
|
|
return len; |
|
bad: |
|
comp->sls_i_error++; |
|
return slhc_toss( comp ); |
|
} |
|
|
|
|
|
int |
|
slhc_remember(struct slcompress *comp, unsigned char *icp, int isize) |
|
{ |
|
struct cstate *cs; |
|
unsigned ihl; |
|
|
|
unsigned char index; |
|
|
|
if(isize < 20) { |
|
/* The packet is shorter than a legal IP header */ |
|
comp->sls_i_runt++; |
|
return slhc_toss( comp ); |
|
} |
|
/* Peek at the IP header's IHL field to find its length */ |
|
ihl = icp[0] & 0xf; |
|
if(ihl < 20 / 4){ |
|
/* The IP header length field is too small */ |
|
comp->sls_i_runt++; |
|
return slhc_toss( comp ); |
|
} |
|
index = icp[9]; |
|
icp[9] = IPPROTO_TCP; |
|
|
|
if (ip_fast_csum(icp, ihl)) { |
|
/* Bad IP header checksum; discard */ |
|
comp->sls_i_badcheck++; |
|
return slhc_toss( comp ); |
|
} |
|
if(index > comp->rslot_limit) { |
|
comp->sls_i_error++; |
|
return slhc_toss(comp); |
|
} |
|
|
|
/* Update local state */ |
|
cs = &comp->rstate[comp->recv_current = index]; |
|
comp->flags &=~ SLF_TOSS; |
|
memcpy(&cs->cs_ip,icp,20); |
|
memcpy(&cs->cs_tcp,icp + ihl*4,20); |
|
if (ihl > 5) |
|
memcpy(cs->cs_ipopt, icp + sizeof(struct iphdr), (ihl - 5) * 4); |
|
if (cs->cs_tcp.doff > 5) |
|
memcpy(cs->cs_tcpopt, icp + ihl*4 + sizeof(struct tcphdr), (cs->cs_tcp.doff - 5) * 4); |
|
cs->cs_hsize = ihl*2 + cs->cs_tcp.doff*2; |
|
cs->initialized = true; |
|
/* Put headers back on packet |
|
* Neither header checksum is recalculated |
|
*/ |
|
comp->sls_i_uncompressed++; |
|
return isize; |
|
} |
|
|
|
int |
|
slhc_toss(struct slcompress *comp) |
|
{ |
|
if ( comp == NULLSLCOMPR ) |
|
return 0; |
|
|
|
comp->flags |= SLF_TOSS; |
|
return 0; |
|
} |
|
|
|
#else /* CONFIG_INET */ |
|
|
|
int |
|
slhc_toss(struct slcompress *comp) |
|
{ |
|
printk(KERN_DEBUG "Called IP function on non IP-system: slhc_toss"); |
|
return -EINVAL; |
|
} |
|
int |
|
slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize) |
|
{ |
|
printk(KERN_DEBUG "Called IP function on non IP-system: slhc_uncompress"); |
|
return -EINVAL; |
|
} |
|
int |
|
slhc_compress(struct slcompress *comp, unsigned char *icp, int isize, |
|
unsigned char *ocp, unsigned char **cpp, int compress_cid) |
|
{ |
|
printk(KERN_DEBUG "Called IP function on non IP-system: slhc_compress"); |
|
return -EINVAL; |
|
} |
|
|
|
int |
|
slhc_remember(struct slcompress *comp, unsigned char *icp, int isize) |
|
{ |
|
printk(KERN_DEBUG "Called IP function on non IP-system: slhc_remember"); |
|
return -EINVAL; |
|
} |
|
|
|
void |
|
slhc_free(struct slcompress *comp) |
|
{ |
|
printk(KERN_DEBUG "Called IP function on non IP-system: slhc_free"); |
|
} |
|
struct slcompress * |
|
slhc_init(int rslots, int tslots) |
|
{ |
|
printk(KERN_DEBUG "Called IP function on non IP-system: slhc_init"); |
|
return NULL; |
|
} |
|
|
|
#endif /* CONFIG_INET */ |
|
|
|
/* VJ header compression */ |
|
EXPORT_SYMBOL(slhc_init); |
|
EXPORT_SYMBOL(slhc_free); |
|
EXPORT_SYMBOL(slhc_remember); |
|
EXPORT_SYMBOL(slhc_compress); |
|
EXPORT_SYMBOL(slhc_uncompress); |
|
EXPORT_SYMBOL(slhc_toss); |
|
|
|
MODULE_LICENSE("Dual BSD/GPL");
|
|
|