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/* |
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ROHC Project 2003 at Lulea University of Technology, Sweden. |
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Authors: Andreas Vernersson <andver-8@student.luth.se> |
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Daniel Pettersson <danpet-7@student.luth.se> |
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Erik Soderstrom <soderstrom@yahoo.com> |
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Fredrik Lindstrom <frelin-9@student.luth.se> |
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Johan Stenmark <johste-8@student.luth.se> |
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Martin Juhlin <juhlin@users.sourceforge.net> |
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Mikael Larsson <larmik-9@student.luth.se> |
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Robert Maxe <robmax-1@student.luth.se> |
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|
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Copyright (C) 2003 Andreas Vernersson, Daniel Pettersson, |
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Erik Soderström, Fredrik Lindström, Johan Stenmark, |
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Martin Juhlin, Mikael Larsson, Robert Maxe. |
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|
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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|
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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/* |
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* Implementation of the uncompressed profile (compressor) |
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*/ |
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|
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#include <linux/ip.h> |
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|
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#include "rohc.h" |
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#include "comp.h" |
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#include "c_util.h" |
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|
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|
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/* |
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Structure that contain counters, flags and structures that need to saved between different |
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packages. Every context have one of these |
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*/ |
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struct sc_uncompressed_context { |
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int ir_count, normal_count; |
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int go_back_ir_count; |
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|
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|
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}; |
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|
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static void uncompressed_decide_state(struct sc_context *context); |
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|
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static void uncompressed_periodic_down_transition(struct sc_context *context); |
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|
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static void uncompressed_change_mode(struct sc_context *c, C_MODE new_mode); |
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|
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static void uncompressed_change_state(struct sc_context *c, C_STATE new_state); |
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|
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static int uncompressed_code_packet(struct sc_context *context, |
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const struct iphdr *ip, |
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unsigned char *dest, |
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int *payload_offset, |
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int max_size); |
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|
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static int uncompressed_code_IR_packet(struct sc_context *context, |
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const struct iphdr *ip, |
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unsigned char *dest, |
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int *payload_offset, |
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int max_size); |
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|
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static int uncompressed_code_normal_packet(struct sc_context *context, |
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const struct iphdr *ip, |
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unsigned char *dest, |
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int *payload_offset, |
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int max_size); |
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|
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/* |
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Function to allocate for a new context, it aslo initilize alot of variables. |
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|
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This function is one of the functions that must exist for the framework to |
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work. Please notice that a pointer to this function has to exist in the |
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sc_profile struct thatwe have in the bottom of this file. |
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*/ |
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int c_uncompressed_create(struct sc_context *context, const struct iphdr *ip) |
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{ |
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struct sc_uncompressed_context *uncompressed_profile; |
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|
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context->profile_context = kmalloc(sizeof(struct sc_uncompressed_context),GFP_ATOMIC); |
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if (context->profile_context == 0) { |
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rohc_debugf(0,"c_ip_create(): no mem for profile context\n"); |
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return 0; |
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} |
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uncompressed_profile = (struct sc_uncompressed_context *)context->profile_context; |
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|
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uncompressed_profile->ir_count = 0; |
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uncompressed_profile->normal_count = 0; |
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|
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uncompressed_profile->go_back_ir_count = 0; |
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return 1; |
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|
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} |
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|
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|
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/* |
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Function to deallocate a context. |
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|
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This function is one of the functions that must exist for the framework to |
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work. Please notice that a pointer to this function has to exist in the |
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sc_profile struct thatwe have in the bottom of this file. |
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*/ |
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void c_uncompressed_destroy(struct sc_context *context){ |
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|
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if (context->profile_context != 0) |
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kfree(context->profile_context); |
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|
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} |
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|
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/* |
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A package can always be sent uncompressed |
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|
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This function is one of the functions that must exist for the framework to |
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work. Please notice that a pointer to this function has to exist in the |
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sc_profile struct that we have in the bottom of this file. |
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*/ |
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int c_uncompressed_check_context(struct sc_context *context, const struct iphdr *ip){ |
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return 1; |
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} |
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|
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/* |
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Encode packages to a pattern decided by two different factors. |
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1. Decide state |
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2. Code packet |
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|
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This function is one of the functions that must exist for the framework to |
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work. Please notice that a pointer to this function has to exist in the |
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sc_profile struct that we have in the bottom of this file. |
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*/ |
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int c_uncompressed_encode(struct sc_context *context, |
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const struct iphdr *ip, |
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int packet_size, |
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unsigned char *dest, |
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int max_size, |
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int *payload_offset) |
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|
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{ |
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int size; |
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|
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// 1 |
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uncompressed_decide_state(context); |
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|
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//2 |
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size = uncompressed_code_packet(context,ip,dest,payload_offset,max_size); |
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|
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return size; |
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} |
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|
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/* |
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Function that update the profile when feedback has arrived. |
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|
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This function is one of the functions that must exist for the framework to |
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work. Please notice that a pointer to this function has to exist in the |
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sc_profile struct that we have in the bottom of this file. |
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*/ |
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void c_uncompressed_feedback(struct sc_context *context, struct sc_feedback *feedback) |
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{ |
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//struct sc_uncompressed_context *uncompressed_context = (struct sc_uncompressed_context *)context->profile_context; |
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unsigned char *p = feedback->data + feedback->specific_offset; |
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|
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if (feedback->type == 1) { // ack |
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|
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} else if (feedback->type == 2) { // FEEDBACK-2 |
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unsigned int crc = 0, crc_used=0; |
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|
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int sn_not_valid = 0; |
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unsigned char mode = (p[0]>>4) & 3; |
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unsigned int sn = ((p[0] & 15) << 8) + p[1]; |
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int remaining = feedback->specific_size-2; |
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p+=2; |
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|
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|
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while (remaining > 0) { |
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int opt = p[0]>>4; |
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int optlen = p[0] & 0x0f; |
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|
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switch (opt) { |
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case 1: // CRC |
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crc = p[1]; |
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crc_used = 1; |
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p[1] = 0; // set to zero for crc computation.. |
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break; |
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//case 2: // Reject |
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//break; |
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case 3: // SN-Not-Valid |
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sn_not_valid=1; |
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break; |
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case 4: // SN -- TODO: how is several SN options combined? |
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sn = (sn<<8) + p[1]; |
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break; |
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//case 7: // Loss |
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//break; |
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default: |
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rohc_debugf(0,"c_ip_feedback(): Unknown feedback type: %d\n", opt); |
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break; |
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} |
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|
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remaining -= 1 + optlen; |
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p += 1 + optlen; |
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} |
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|
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if (crc_used) { // check crc.. |
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if (crc_calculate(CRC_TYPE_8, feedback->data, feedback->size ) != crc) { |
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rohc_debugf(0,"c_ip_feedback(): crc check failed..(size=%d)\n", feedback->size); |
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return; |
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} |
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} |
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|
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if (mode != 0) { |
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if (crc_used) { |
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uncompressed_change_mode(context, mode); |
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rohc_debugf(1,"c_ip_feedback(): changing mode to %d\n", mode); |
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} else { |
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rohc_debugf(0,"c_ip_feedback(): mode change requested but no crc was given..\n"); |
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} |
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} |
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|
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switch (feedback->acktype) { |
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case ACK: |
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|
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break; |
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|
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case NACK: |
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|
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|
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break; |
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|
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case STATIC_NACK: |
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uncompressed_change_state(context, IR); |
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break; |
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|
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case RESERVED: |
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rohc_debugf(0, "c_ip_feedback(): reserved field used\n"); |
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break; |
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} |
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|
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} else { |
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rohc_debugf(0,"c_ip_feedback(): Feedback type not implemented (%d)\n", feedback->type); |
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} |
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|
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} |
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|
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/* Decide the state we will work in. Observe that RFC3095 defines the states as ir and normal, but here |
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we call normal state FO instead*/ |
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void uncompressed_decide_state(struct sc_context *context) |
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{ |
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struct sc_uncompressed_context *uncompressed_profile = (struct sc_uncompressed_context *)context->profile_context; |
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|
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if(context->c_state == IR && uncompressed_profile->ir_count >= MAX_IR_COUNT){ |
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uncompressed_change_state(context, FO); |
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} |
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if(context->c_mode == U){ |
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uncompressed_periodic_down_transition(context); |
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} |
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} |
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|
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/*Function that change state periodicly after a certain number of packets */ |
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void uncompressed_periodic_down_transition(struct sc_context *context) |
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{ |
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struct sc_uncompressed_context *uncompressed_profile = (struct sc_uncompressed_context *)context->profile_context; |
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if(uncompressed_profile->go_back_ir_count == CHANGE_TO_IR_COUNT){ |
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uncompressed_profile->go_back_ir_count = 0; |
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uncompressed_change_state(context, IR); |
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} |
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if (context->c_state == FO) |
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uncompressed_profile->go_back_ir_count++; |
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|
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} |
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|
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// Change the mode of this context |
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void uncompressed_change_mode(struct sc_context *c, C_MODE new_mode) { |
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if(c->c_mode != new_mode){ |
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c->c_mode = new_mode; |
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uncompressed_change_state(c, IR); |
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} |
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} |
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|
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// Change the state of this context |
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void uncompressed_change_state(struct sc_context *context, C_STATE new_state) |
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{ |
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|
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struct sc_uncompressed_context *uncompressed_profile = (struct sc_uncompressed_context *)context->profile_context; |
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// Reset counters only if different state |
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if (context->c_state != new_state) { |
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uncompressed_profile->ir_count = 0; |
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uncompressed_profile->normal_count = 0; |
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|
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} |
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|
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context->c_state = new_state; |
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} |
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|
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/* |
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Code the packet, it is eiter IR or normal |
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*/ |
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int uncompressed_code_packet(struct sc_context *context, |
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const struct iphdr *ip, |
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unsigned char *dest, |
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int *payload_offset, |
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int max_size){ |
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|
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struct sc_uncompressed_context *uncompressed_profile = (struct sc_uncompressed_context *)context->profile_context; |
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switch(context->c_state){ |
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case IR: |
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rohc_debugf(1,"uncompressed_code_packet(): IR packet uncomp..\n"); |
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uncompressed_profile->ir_count++; |
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return uncompressed_code_IR_packet(context,ip,dest,payload_offset,max_size); |
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break; |
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case FO: |
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rohc_debugf(1,"uncompressed_code_packet(): normal packet uncomp..\n"); |
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uncompressed_profile->normal_count++; |
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return uncompressed_code_normal_packet(context,ip,dest,payload_offset,max_size); |
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break; |
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default: |
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rohc_debugf(0,"uncompressed_code_packet(): Unknown packet..\n"); |
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return -1; |
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} |
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} |
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/* |
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|
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IR packet (5.10.1) |
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|
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0 1 2 3 4 5 6 7 |
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--- --- --- --- --- --- --- --- |
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1 : Add-CID octet : if for small CIDs and (CID != 0) |
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+---+---+---+---+---+---+---+---+ |
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2 | 1 1 1 1 1 1 0 |res| |
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+---+---+---+---+---+---+---+---+ |
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: : |
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3 / 0-2 octets of CID info / 1-2 octets if for large CIDs |
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: : |
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+---+---+---+---+---+---+---+---+ |
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4 | Profile = 0 | 1 octet |
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+---+---+---+---+---+---+---+---+ |
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5 | CRC | 1 octet |
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+---+---+---+---+---+---+---+---+ |
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: : (optional) |
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/ IP packet / variable length |
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: : |
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--- --- --- --- --- --- --- --- |
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|
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*/ |
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int uncompressed_code_IR_packet(struct sc_context *context, |
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const struct iphdr *ip, |
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unsigned char *dest, |
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int *payload_offset, |
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int max_size){ |
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|
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int counter = 0; |
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int first_position; |
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|
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rohc_debugf(2,"Coding IR packet (cid=%d)\n", context->cid); |
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//Both 1 and 3, 2 will be placed in dest[first_position] |
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counter = code_cid_values(context,dest,max_size,&first_position); |
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|
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// 2 |
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dest[first_position] = 0xfc; |
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|
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// 4 |
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dest[counter] = 0; |
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counter++; |
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|
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// 5 |
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dest[counter]= crc_calculate(CRC_TYPE_8,dest,counter); |
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counter++; |
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*payload_offset = 0; |
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return counter; |
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} |
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/* |
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|
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Normal packet (5.10.2) |
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|
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0 1 2 3 4 5 6 7 |
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--- --- --- --- --- --- --- --- |
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1 : Add-CID octet : if for small CIDs and (CID != 0) |
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+---+---+---+---+---+---+---+---+ |
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2 | first octet of IP packet | |
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+---+---+---+---+---+---+---+---+ |
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: : |
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3 / 0-2 octets of CID info / 1-2 octets if for large CIDs |
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: : |
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+---+---+---+---+---+---+---+---+ |
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| | |
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/ rest of IP packet / variable length |
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| | |
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+---+---+---+---+---+---+---+---+ |
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|
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*/ |
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int uncompressed_code_normal_packet(struct sc_context *context, |
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const struct iphdr *ip, |
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unsigned char *dest, |
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int *payload_offset, |
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int max_size) |
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{ |
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|
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int counter = 0; |
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int first_position; |
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|
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|
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rohc_debugf(2,"Coding normal packet (cid=%d)\n", context->cid); |
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//Both 1 and 3, 2 will be placed in dest[first_position] |
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counter = code_cid_values(context,dest,max_size,&first_position); |
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|
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// 2 |
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|
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dest[first_position] = ((unsigned char *)ip)[0]; |
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|
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*payload_offset = 1; |
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return counter; |
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} |
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|
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/* |
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A struct thate every function must have the first fieldtell what protocol this profile has. |
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The second row is the profile id-number, Then two strings that is for printing version and |
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description. And finaly pointers to functions that have to exist in every profile. |
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*/ |
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struct sc_profile c_uncompressed_profile = { |
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0, // IP-Protocol |
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0, // Profile ID |
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"1.0b", // Version |
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"Uncompressed / Compressor", // Description |
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c_uncompressed_create, |
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c_uncompressed_destroy, |
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c_uncompressed_check_context, |
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c_uncompressed_encode, |
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c_uncompressed_feedback |
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}; |