mirror of
https://github.com/ValdikSS/GoodbyeDPI.git
synced 2024-12-22 06:15:27 +00:00
Serious refactoring
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ValdikSS
parent
87c354addf
commit
da1e2e8aac
127
goodbyedpi.c
127
goodbyedpi.c
@ -4,6 +4,7 @@
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#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <signal.h>
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#include <unistd.h>
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#include <string.h>
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@ -15,7 +16,7 @@
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sleep(10); exit(EXIT_FAILURE); } while (0)
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#define MAX_FILTERS 4
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#define MAX_PACKET_SIZE 1516
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#define MAX_PACKET_SIZE 9016
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#define IPV4_HDR_LEN 20
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#define TCP_HDR_LEN 20
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#define IPV4_TOTALLEN_OFFSET 2
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@ -57,7 +58,7 @@ static const char *http_methods[] = {
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static char* dumb_memmem(const char* haystack, int hlen, const char* needle, int nlen) {
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// naive implementation
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if (nlen > hlen) return 0;
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if (nlen > hlen) return NULL;
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int i;
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for (i=0; i<hlen-nlen+1; i++) {
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if (memcmp(haystack+i,needle,nlen)==0) {
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@ -83,9 +84,9 @@ static HANDLE init(char *filter, UINT64 flags) {
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static int deinit(HANDLE handle) {
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if (handle) {
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WinDivertClose(handle);
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return 1;
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return TRUE;
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}
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return 0;
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return FALSE;
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}
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static void deinit_all() {
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@ -107,26 +108,49 @@ static int is_passivedpi_redirect(const char *pktdata, int pktlen) {
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/* Then check if this is a redirect to new http site with Connection: close */
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if (dumb_memmem(pktdata, pktlen, location_http, strlen(location_http)) &&
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dumb_memmem(pktdata, pktlen, connection_close, strlen(connection_close))) {
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return 1;
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return TRUE;
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}
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}
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return 0;
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return FALSE;
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}
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/* Finds Host header with \r\n before it */
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static PVOID find_host_header(const char *pktdata, int pktlen) {
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return dumb_memmem(pktdata, pktlen,
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http_host_find, strlen(http_host_find));
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}
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static int find_header_and_get_info(const char *pktdata, int pktlen,
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const char *hdrname,
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char **hdrnameaddr,
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char **hdrvalueaddr, int *hdrvaluelen) {
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char *data_addr_rn;
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char *hdr_begin;
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/* Finds User-Agent header with \r\n before it */
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static PVOID find_useragent_header(const char *pktdata, int pktlen) {
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return dumb_memmem(pktdata, pktlen,
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http_useragent_find, strlen(http_useragent_find));
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*hdrvaluelen = 0;
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*hdrnameaddr = NULL;
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*hdrvalueaddr = NULL;
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/* Search for the header */
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hdr_begin = dumb_memmem(pktdata, pktlen,
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hdrname, strlen(hdrname));
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if (!hdr_begin) return FALSE;
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if ((PVOID)pktdata > (PVOID)hdr_begin) return FALSE;
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/* Set header address */
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*hdrnameaddr = hdr_begin;
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*hdrvalueaddr = (PVOID)hdr_begin + strlen(hdrname);
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/* Search for header end (\r\n) */
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data_addr_rn = dumb_memmem(*hdrvalueaddr,
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pktlen - ((PVOID)*hdrvalueaddr - (PVOID)pktdata),
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"\r\n", 2);
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if (data_addr_rn) {
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*hdrvaluelen = (PVOID)data_addr_rn - (PVOID)*hdrvalueaddr;
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if (*hdrvaluelen > 0 && *hdrvaluelen <= 512)
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return TRUE;
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}
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return FALSE;
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}
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static void change_window_size(const char *pkt, int size) {
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if (size >= 1 && size <= 65535) {
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*(uint16_t*)(pkt + IPV4_HDR_LEN + TCP_WINDOWSIZE_OFFSET) = htons(size);
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}
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}
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/* HTTP method end without trailing space */
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@ -167,8 +191,11 @@ int main(int argc, char *argv[]) {
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do_host_removespace = 0, do_additional_space = 0;
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int http_fragment_size = 2;
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int https_fragment_size = 2;
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char *data_addr, *data_addr_rn, *host_addr, *useragent_addr, *method_addr;
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int data_len, host_len;
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char *host_addr, *useragent_addr, *method_addr;
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int host_len, useragent_len;
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char *hdr_name_addr = NULL, *hdr_value_addr = NULL;
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int hdr_value_len;
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printf("GoodbyeDPI: Passive DPI blocker and Active DPI circumvention utility\n");
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@ -316,7 +343,7 @@ int main(int argc, char *argv[]) {
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should_reinject = 0;
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}
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}
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/* Handle OUTBOUND packet, search for Host header */
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/* Handle OUTBOUND packet on port 80, search for Host header */
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else if (addr.Direction == WINDIVERT_DIRECTION_OUTBOUND &&
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packet_dataLen > 16 && ppTcpHdr->DstPort == htons(80) &&
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find_http_method_end(packet_data,
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@ -324,34 +351,42 @@ int main(int argc, char *argv[]) {
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(do_host || do_host_removespace))
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{
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data_addr = find_host_header(packet_data, packet_dataLen);
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if (data_addr) {
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/* Find Host header */
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if (find_header_and_get_info(packet_data, packet_dataLen,
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http_host_find, &hdr_name_addr, &hdr_value_addr, &hdr_value_len)) {
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host_addr = hdr_value_addr;
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host_len = hdr_value_len;
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if (do_host) {
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/* Replace "Host: " with "hoSt: " */
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memcpy(data_addr, http_host_replace, strlen(http_host_replace));
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memcpy(hdr_name_addr, http_host_replace, strlen(http_host_replace));
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should_recalc_checksum = 1;
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//printf("Replaced Host header!\n");
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}
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/* If removing space between host header and its value
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* and adding additional space between Method and Request-URI */
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if (do_additional_space && do_host_removespace) {
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/* End of "Host:" without trailing space */
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host_addr = data_addr + strlen(http_host_find) - 1;
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method_addr = find_http_method_end(packet_data,
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(do_fragment_http ? http_fragment_size : 0));
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if (method_addr) {
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memmove(method_addr + 1, method_addr, (PVOID)host_addr - (PVOID)method_addr);
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memmove(method_addr + 1, method_addr,
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(PVOID)host_addr - (PVOID)method_addr - 1);
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should_recalc_checksum = 1;
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}
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}
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/* If just removing space between host header and its value */
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else if (do_host_removespace) {
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host_addr = data_addr + strlen(http_host_find);
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if (find_header_and_get_info(packet_data, packet_dataLen,
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http_useragent_find, &hdr_name_addr,
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&hdr_value_addr, &hdr_value_len))
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{
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useragent_addr = hdr_value_addr;
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useragent_len = hdr_value_len;
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data_addr_rn = dumb_memmem(host_addr,
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packet_dataLen - ((PVOID)host_addr - packet_data),
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"\r\n", 2);
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if (data_addr_rn) {
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/* We move Host header value by one byte to the left and then
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* "insert" stolen space to the end of User-Agent value because
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* some web servers are not tolerant to additional space in the
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@ -359,58 +394,48 @@ int main(int argc, char *argv[]) {
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*
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* Nothing is done if User-Agent header is missing.
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*/
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host_len = data_addr_rn - host_addr;
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useragent_addr = find_useragent_header(packet_data, packet_dataLen);
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if (host_len <= 253 && useragent_addr) {
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useragent_addr += strlen(http_useragent_find);
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if (host_len > 0 && host_len <= 253 &&
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useragent_addr && useragent_len > 0) {
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/* useragent_addr is in the beginning of User-Agent value */
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data_len = packet_dataLen - ((PVOID)useragent_addr - packet_data);
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data_addr_rn = dumb_memmem(useragent_addr,
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data_len, "\r\n", 2);
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/* data_addr_rn is in the end of User-Agent value */
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if (data_addr_rn) {
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if (useragent_addr > host_addr) {
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/* User-Agent goes AFTER Host header */
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data_len = (PVOID)data_addr_rn - (PVOID)host_addr;
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/* Move one byte to the LEFT from "Host:"
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* to the end of User-Agent
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*/
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memmove(host_addr - 1, host_addr, data_len);
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memmove(host_addr - 1, host_addr, useragent_len);
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host_addr -= 1;
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/* Put space in the end of User-Agent header */
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*(char*)(data_addr_rn - 1) = ' ';
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*(char*)((PVOID)useragent_addr + useragent_len - 1) = ' ';
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should_recalc_checksum = 1;
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//printf("Replaced Host header!\n");
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}
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else {
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/* User-Agent goes BEFORE Host header */
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data_len = (PVOID)host_addr - (PVOID)data_addr_rn - 1;
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/* Move one byte to the RIGHT from the end of User-Agent
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* to the "Host:"
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*/
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memmove(data_addr_rn + 1, data_addr_rn, data_len);
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memmove((PVOID)useragent_addr + useragent_len + 1,
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(PVOID)useragent_addr + useragent_len,
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useragent_len - 1);
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/* Put space in the end of User-Agent header */
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*(char*)(data_addr_rn) = ' ';
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*(char*)((PVOID)useragent_addr + useragent_len) = ' ';
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should_recalc_checksum = 1;
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//printf("Replaced Host header!\n");
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}
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} /* if (dara_addr_rn) */
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} /* if (host_len <= 253 && useragent_addr) */
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} /* if (data_addr_rn) */
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} /* if (find_header_and_get_info http_useragent) */
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} /* else if (do_host_removespace) */
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} /* if (data_addr) */
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} /* if (find_header_and_get_info http_host) */
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} /* Handle OUTBOUND packet with data */
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} /* Handle packet with data */
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/* Else if we got TCP packet without data */
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else if (WinDivertHelperParsePacket(packet, packetLen, &ppIpHdr,
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NULL, NULL, NULL, &ppTcpHdr, NULL, NULL, NULL)) {
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/* If we got SYN+ACK packet */
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/* If we got INBOUND SYN+ACK packet */
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if (addr.Direction == WINDIVERT_DIRECTION_INBOUND &&
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ppTcpHdr->Syn == 1) {
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ppTcpHdr->Syn == 1 && ppTcpHdr->Ack == 1) {
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//printf("Changing Window Size!\n");
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if (do_fragment_http && ppTcpHdr->SrcPort == htons(80)) {
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change_window_size(packet, http_fragment_size);
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