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/*
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* iphelp.cpp - ip router
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*
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* Basilisk II (C) 1997-2001 Christian Bauer
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*
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* Windows platform specific code copyright (C) Lauri Pesonen
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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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#include "sysdeps.h"
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#include "cpu_emulation.h"
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#include "ether_windows.h"
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#include "ether.h"
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#include "router.h"
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#include "router_types.h"
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#include "tcp.h"
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#include "icmp.h"
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#include "udp.h"
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#include "iphelp.h"
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#include "dump.h"
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#if DEBUG
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#pragma optimize("",off)
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#endif
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#include "debug.h"
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void make_icmp_checksum( icmp_t *icmp, int len )
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{
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icmp->checksum = 0;
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uint16 sz = (len-sizeof(ip_t))/2;
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uint16 *p = (uint16 *)( (uint8 *)icmp + sizeof(ip_t) );
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uint32 sum32 = 0;
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for( int i=0; i<sz; i++ ) {
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sum32 += ntohs(p[i]);
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}
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while( HIWORD(sum32) ) {
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sum32 = HIWORD(sum32) + LOWORD(sum32);
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}
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sum32 = ~sum32;
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icmp->checksum = htons((uint16)sum32);
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}
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void make_tcp_checksum( tcp_t *tcp, int len )
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{
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tcp->checksum = 0;
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int tcp_len = len - sizeof(ip_t);
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uint16 sz = tcp_len/2;
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uint16 *p = (uint16 *)( (uint8 *)tcp + sizeof(ip_t) );
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uint32 sum32 = 0;
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for( int i=0; i<sz; i++ ) {
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sum32 += ntohs(p[i]);
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}
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if(len & 1) {
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uint8 *p8 = (uint8 *)p;
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sum32 += p8[tcp_len-1] << 8;
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}
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pseudo_ip_t pseudo;
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pseudo.src_lo = LOWORD(ntohl(tcp->ip.src));
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pseudo.src_hi = HIWORD(ntohl(tcp->ip.src));
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pseudo.dest_lo = LOWORD(ntohl(tcp->ip.dest));
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pseudo.dest_hi = HIWORD(ntohl(tcp->ip.dest));
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pseudo.proto = (uint16)tcp->ip.proto;
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pseudo.msg_len = tcp->header_len >> 2;
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int datalen = len - sizeof(tcp_t);
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pseudo.msg_len += datalen;
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p = (uint16 *)&pseudo;
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for( int i=0; i<sizeof(pseudo_ip_t)/2; i++ ) {
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sum32 += p[i];
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}
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while( HIWORD(sum32) ) {
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sum32 = HIWORD(sum32) + LOWORD(sum32);
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}
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sum32 = ~sum32;
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tcp->checksum = htons((uint16)sum32);
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}
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void make_ip4_checksum( ip_t *ip )
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{
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ip->checksum = 0;
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uint16 sz = ip->header_len * 2;
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uint16 *p = (uint16 *)( (uint8 *)ip + sizeof(mac_t) );
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uint32 sum32 = 0;
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for( int i=0; i<sz; i++ ) {
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sum32 += ntohs(p[i]);
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}
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while( HIWORD(sum32) ) {
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sum32 = HIWORD(sum32) + LOWORD(sum32);
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}
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sum32 = ~sum32;
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ip->checksum = htons((uint16)sum32);
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}
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void make_udp_checksum( udp_t *udp )
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{
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udp->checksum = 0;
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return;
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// UDP checksums are optional.
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/*
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uint16 sz = ntohs(udp->msg_len) / 2;
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uint16 *p = (uint16 *)( (uint8 *)udp + sizeof(ip_t) );
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uint32 sum32 = 0;
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for( int i=0; i<sz; i++ ) {
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sum32 += ntohs(p[i]);
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}
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// last byte??
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pseudo_ip_t pseudo;
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pseudo.src_lo = LOWORD(ntohl(udp->ip.src));
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pseudo.src_hi = HIWORD(ntohl(udp->ip.src));
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pseudo.dest_lo = LOWORD(ntohl(udp->ip.dest));
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pseudo.dest_hi = HIWORD(ntohl(udp->ip.dest));
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pseudo.proto = (uint16)udp->ip.proto;
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pseudo.msg_len = ntohs(udp->msg_len); // ???
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p = (uint16 *)&pseudo;
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for( i=0; i<sizeof(pseudo_ip_t)/2; i++ ) {
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sum32 += p[i];
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}
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while( HIWORD(sum32) ) {
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sum32 = HIWORD(sum32) + LOWORD(sum32);
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}
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sum32 = ~sum32;
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udp->checksum = htons((uint16)sum32);
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*/
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}
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void error_winsock_2_icmp( int err, ip_t *ip_err, int dlen_err )
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{
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int type = -1, code = -1, msg_size = 0;
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switch( err ) {
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case WSAEHOSTUNREACH:
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case WSAETIMEDOUT:
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type = icmp_Destination_unreachable;
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code = 1; // Host unreachable
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msg_size = (ip_err->header_len << 2) + 4 + 8; // ip header + unused + 64 msg bits
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break;
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case WSAENETDOWN:
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case WSAENETUNREACH:
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type = icmp_Destination_unreachable;
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code = 0; // Network unreachable
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msg_size = (ip_err->header_len << 2) + 4 + 8; // ip header + unused + 64 msg bits
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break;
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case WSAETTLEXCEEDED:
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type = icmp_Time_exceeded;
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code = 0; // Transit TTL exceeded
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msg_size = (ip_err->header_len << 2) + 4 + 8; // ip header + unused + 64 msg bits
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break;
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}
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if(type >= 0 && macos_ip_address != 0) {
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D(bug("sending icmp error reply. type=%d, code=%d, msg_size=%d\r\n", type, code, msg_size));
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int icmp_size = sizeof(icmp_t) + msg_size;
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icmp_t *icmp = (icmp_t *)malloc( icmp_size );
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if(icmp) {
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mac_t *mac = (mac_t *)icmp;
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ip_t *ip = (ip_t *)icmp;
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memcpy( mac->dest, ether_addr, 6 );
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memcpy( mac->src, router_mac_addr, 6 );
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mac->type = htons(mac_type_ip4);
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ip->version = 4;
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ip->header_len = 5;
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ip->tos = 0;
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ip->total_len = htons(sizeof(icmp_t) - sizeof(mac_t) + msg_size);
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ip->ident = htons(next_ip_ident_number++);
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ip->flags_n_frag_offset = 0;
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ip->ttl = 128;
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ip->proto = ip_proto_icmp;
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ip->src = htonl(router_ip_address);
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ip->dest = htonl(macos_ip_address);
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make_ip4_checksum( ip );
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icmp->type = type;
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icmp->code = code;
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// zero out the unused field
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memset( (char *)icmp + sizeof(icmp_t), 0, sizeof(uint32) );
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// copy 64 bits of original message
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memcpy(
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(char *)icmp + sizeof(icmp_t) + sizeof(uint32),
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(char *)ip_err + sizeof(mac_t),
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msg_size
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);
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make_icmp_checksum( icmp, icmp_size );
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dump_bytes( (uint8 *)icmp, icmp_size );
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enqueue_packet( (uint8 *)icmp, icmp_size );
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free(icmp);
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}
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}
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}
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