Merge pull request #98 from Waujito/kmod

Kernel module
2024-12-22 06:15:31 +00:00 · 2024-09-21 08:11:01 -07:00 · 2024-09-21 08:11:01 -07:00 · cdb26833ba
commit cdb26833ba
parent edbfe120c5 c786a44dd5
21 changed files with 1357 additions and 518 deletions
--- a/.github/workflows/build-ci.yml
+++ b/.github/workflows/build-ci.yml
@ -93,7 +93,7 @@ jobs:
        if: steps.build.outcome == 'success'
        uses: actions/upload-artifact@v4
        with:
-          name: static-${{ matrix.arch }}
+          name: youtubeUnblock-static-${{ matrix.arch }}
          path: ./**/youtubeUnblock*.tar.gz

  build-static-cross:
@ -225,10 +225,108 @@ jobs:
        if: steps.build.outcome == 'success'
        uses: actions/upload-artifact@v4
        with:
-          name: ${{ matrix.branch }}-${{ matrix.arch }}
+          name: youtubeUnblock-${{ matrix.branch }}-${{ matrix.arch }}
          path: /builder/youtubeUnblock*.ipk
          if-no-files-found: error

+
+  build-openwrt-kmod:
+    needs: prepare
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        branch:
+          - openwrt-23.05
+          - openwrt-22.03
+          - openwrt-21.02
+          - openwrt-19.07
+        include:
+          - branch: openwrt-23.05
+            wd_path: /builder
+          - branch: openwrt-22.03
+            wd_path: /builder
+          - branch: openwrt-21.02
+            wd_path: /builder
+          - branch: openwrt-19.07
+            wd_path: /home/build/openwrt
+        arch:
+          - aarch64_cortex-a53
+          - aarch64_cortex-a72
+          - aarch64_generic
+          - arm_arm1176jzf-s_vfp
+          - arm_arm926ej-s
+          - arm_cortex-a15_neon-vfpv4
+          - arm_cortex-a5_vfpv4
+          - arm_cortex-a7
+          - arm_cortex-a7_neon-vfpv4
+          - arm_cortex-a7_vfpv4
+          - arm_cortex-a8_vfpv3
+          - arm_cortex-a9
+          - arm_cortex-a9_neon
+          - arm_cortex-a9_vfpv3-d16
+          - arm_fa526
+          - arm_mpcore
+          - arm_xscale
+          - mips64_octeonplus
+          - mips_24kc
+          - mips_4kec
+          - mips_mips32
+          - mipsel_24kc
+          - mipsel_24kc_24kf
+          - mipsel_74kc
+          - mipsel_mips32
+          - ramips-mt76x8
+          - x86_64
+        exclude:
+          - branch: openwrt-19.07
+            arch: arm_cortex-a7
+          - branch: openwrt-19.07
+            arch: mips_4kec
+          - branch: openwrt-19.07
+            arch: ramips-mt76x8
+          - branch: openwrt-19.07
+            arch: arm_cortex-a7_vfpv4
+          - branch: openwrt-21.02
+            arch: arm_cortex-a7_vfpv4
+
+    container:
+      image: openwrt/sdk:${{ matrix.arch }}-${{ matrix.branch }}
+      options: --user root
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          ref: 'openwrt'
+
+      - name: Prepare build
+        env:
+          VERSION: ${{ needs.prepare.outputs.version }}
+          SHA: ${{ needs.prepare.outputs.sha }}
+        run: |
+          sed -i "s/PKG_REV:=.*$/PKG_REV:=$SHA/;s/PKG_VERSION:=.*$/PKG_VERSION:=$VERSION-$SHA/" kyoutubeUnblock/Makefile
+      - name: Build packages
+        id: build
+        env:
+          VERSION: ${{ needs.prepare.outputs.version }}
+          SHA: ${{ needs.prepare.outputs.sha }}
+        working-directory: ${{ matrix.wd_path }}
+        run: |
+          pwd
+          echo "src-link youtubeUnblock $GITHUB_WORKSPACE" >> feeds.conf
+          cat feeds.conf
+          ./scripts/feeds update youtubeUnblock
+          ./scripts/feeds install -a -p youtubeUnblock
+          make defconfig
+          make package/kyoutubeUnblock/compile V=s
+          cp $(find ./bin -type f -name 'kmod-youtubeUnblock*.ipk') ./
+      - name: Upload packages
+        if: steps.build.outcome == 'success'
+        uses: actions/upload-artifact@v4
+        with:
+          name: kmod-youtubeUnblock-${{ matrix.branch }}-${{ matrix.arch }}
+          path: ${{ matrix.wd_path }}/kmod-youtubeUnblock*.ipk
+          if-no-files-found: error
+
  build-entware:
    needs: prepare
    runs-on: ubuntu-latest
@ -317,13 +415,13 @@ jobs:
        if: steps.build.outcome == 'success'
        uses: actions/upload-artifact@v4
        with:
-          name: entware-${{ matrix.arch }}
+          name: youtubeUnblock-entware-${{ matrix.arch }}
          path: ./**/youtubeUnblock*-entware.tar.gz
          if-no-files-found: error

  pre-release:
    if: github.event_name != 'pull_request' && github.ref_name == 'main'
-    needs: [build-static, build-static-cross, build-openwrt, build-entware]
+    needs: [build-static, build-static-cross, build-openwrt, build-entware, build-openwrt-kmod]
    permissions:
      contents: write
    runs-on: ubuntu-latest
@ -340,4 +438,5 @@ jobs:
          title: 'Development build'
          files: |
            ./**/youtubeUnblock*.ipk
+            ./**/kmod-youtubeUnblock*.ipk
            ./**/youtubeUnblock*.tar.gz
--- a/6
+++ b/6
@ -1,3 +1,3 @@
-obj-m := ipt_YTUNBLOCK.o
-ipt_YTUNBLOCK-objs := iptk_YTUNBLOCK.o mangle.o
-ccflags-y := -std=gnu11 -Wno-unused-variable -DKERNEL_SPACE -DDEBUG
+obj-m := kyoutubeUnblock.o
+kyoutubeUnblock-objs := kytunblock.o mangle.o quic.o utils.o kmod_utils.o kargs.o
+ccflags-y := -std=gnu99 -DKERNEL_SPACE -Wno-error -Wno-declaration-after-statement
--- a/README.md
+++ b/README.md
@ -16,6 +16,11 @@
  - [OpenWRT case](#openwrt-case)
    - [Building OpenWRT .ipk package](#building-openwrt-ipk-package)
    - [Building with toolchain](#building-with-toolchain)
+  - [Kernel module](#kernel-module)
+    - [Building kernel module](#building-kernel-module)
+      - [Building on host system](#building-on-host-system)
+      - [Building on any kernel](#building-on-any-kernel)
+      - [Building with openwrt SDK](#building-with-openwrt-sdk)


 # youtubeUnblock
@ -35,6 +40,10 @@ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 ```

+The program is distributed in two version:
+- A userspace application works on top of nfnetlink queue which requires nfnetlink modules in the kernel and firewall rules. This approach is default and normally should be used but it has some limitations on embedded devices which may have no nfnetlink support. Also this solution may break down the internet speed and CPU load on your device because of jumps between userspace and kernelspace for each packet (this behavior may be fixed with connbytes but it also requires conntrack kernel module).
+- A kernel module which integrates deeply within the netfilter stack and does not interact with the userspace firewall. The module requires only netfilter kernel support but it definetly present on every device connected to the Internet. The only difficulity is how to build it. I cannot provide modules within Github Actions for each single one kernel, even if we talk only about OpenWRT versions. If you want to learn more about the module, jump on [its section in the README](#kernel-module)
+
 The program is compatible with routers based on OpenWRT, Entware(Keenetic/ASUS) and host machines. The program offers binaries via Github Actions. The binaries of main branch are published in the [development pre-release](https://github.com/Waujito/youtubeUnblock/releases/tag/continuous). Check out [Github Actions](https://github.com/Waujito/youtubeUnblock/actions/workflows/build-ci.yml) if you want to see all the binaries compiled ever. You should know the arcitecture of your hardware to use binaries. On OpenWRT you can check it with command `grep ARCH /etc/openwrt_release`.

 On both OpenWRT and Entware install the program with opkg. If you got read-only filesystem error you may unpack the binary manually or specify opkg path `opkg -o <destdir>`.
@ -301,5 +310,64 @@ Take a look at `CROSS_COMPILE_PLATFORM` It is required by autotools but I think

 When compilation is done, the binary file will be in build directory. Copy it to your router. Note that a ssh access is likely to be required to proceed. *sshfs* don't work on my model so I injected the application to the router via *Software Upload Package* page. It has given me an error, but also a `/tmp/upload.ipk` file which I copied in root directory, `chmod +x` it and run.

+## Kernel module
+
+This section describes the kernel module version of youtubeUnblock. The kernel module operates as a normal module inside the kernel and integrates within the netfilter stack to statelessly mangle the packets sent over the Internet.
+
+You can configure the module with its flags in insmod:
+```
+insmod kyoutubeUnblock.ko fake_sni=1 exclude_domains=.ru quic_drop=1
+```
+
+Note that the flags names are different from ones used for the regular youtubeUnblock(right like in UCI configuration for OpenWRT): replace `-` with `_` and no leading `--`. Also to configure togglers you should set them to `1` (`silent=1 quic_drop=1`)
+
+Also a drop in replacement is supported for all the parameters excluding packet mark. A drop in replacement does not require module restart if you want to change the parameters. You can specify and check the parameters within module's directory inside the sysfs: `/sys/module/kyoutubeUnblock/parameters/`. For example, to set quic_drop to true you may use next command:
+```sh
+echo 1 | sudo tee /sys/module/kyoutubeUnblock/parameters/quic_drop
+```
+and 
+```sh
+cat /sys/module/kyoutubeUnblock/parameters/quic_drop
+```
+to check the parameter.
+
+### Building kernel module
+
+#### Building on host system
+
+To build the kernel module on your host system you should install `linux-headers` which will provide build essential tools and `gcc` compiler suite. On host system you may build the module with 
+```sh
+make kmake
+```
+
+#### Building on any kernel
+
+To build the module for external kernel you should build that kernel locally and point make to it. Use `KERNEL_BUILDER_MAKEDIR=~/linux` flag for make, for example:
+```
+make kmake KERNEL_BUILDER_MAKEDIR=~/linux
+```
+Note, that the kernel should be already configured and built. See linux kernel building manuals for more information about your specific case.
+
+#### Building with openwrt SDK
+
+Building with openwrt SDK is not such a hard thing. The only thing you should do is to obtain the sdk. You can find it by looking to your architecture and version of the openwrt currently used. You should use the exactly your version of openwrt since kernels there change often. You can find the sdk in two ways: by downloading it from their site or by using the openwrt sdk docker container (recommended).
+
+If you decide to download the tar archive, follow next steps:
+For me the archive lives in https://downloads.openwrt.org/releases/23.05.3/targets/ramips/mt76x8/ and called `openwrt-sdk-23.05.3-ramips-mt76x8_gcc-12.3.0_musl.Linux-x86_64`. You will need to [install sdk requirements on your system](https://openwrt.org/docs/guide-developer/toolchain/install-buildsystem) If you have any problems, use docker ubuntu:24.04 image. Make sure to be a non-root user since some makesystem fails with it. Next, untar the SDK and cd into it. 
+
+Or you can obtain the docker image with sdk built-in: [https://hub.docker.com/u/openwrt/sdk](https://hub.docker.com/u/openwrt/sdk). In my case the image has tag `ramips-mt76x8-23.05.3`. A good thing here is that you don't need to install any dependencies inside the docker container. Also docker hub has a perfect search around tags if you don't sure which one corresponds to your device.
+
+When you unpacked/installed the sdk, you is ready to start with building the kernel module.
+
+Do
+```sh
+echo "src-git youtubeUnblock https://github.com/Waujito/youtubeUnblock.git;openwrt" >> feeds.conf
+./scripts/feeds update youtubeUnblock
+./scripts/feeds install -a -p youtubeUnblock
+make defconfig
+make package/kyoutubeUnblock/compile V=s
+```
+
+When the commands finish, the module is ready. Find it with `find bin -name "kmod-youtubeUnblock*.ipk"`, copy to your host and install to the router via gui software interface. The module should start immediately. If not, do `modprobe kyoutubeUnblock`.

 >If you have any questions/suggestions/problems feel free to open an [issue](https://github.com/Waujito/youtubeUnblock/issues).
--- a/config.h
+++ b/config.h
@ -1,6 +1,10 @@
 #ifndef YTB_CONFIG_H
 #define YTB_CONFIG_H

+#ifndef KERNEL_SPACE
+#define USER_SPACE
+#endif
+
 typedef int (*raw_send_t)(const unsigned char *data, unsigned int data_len);
 /**
 * Sends the packet after delay_ms. The function should schedule send and return immediately
@ -110,6 +114,8 @@ extern struct config_t config;

 #define MAX_PACKET_SIZE 8192

-static const char defaul_snistr[] = "googlevideo.com,ggpht.com,ytimg.com,youtube.com,play.google.com,youtu.be,googleapis.com,googleusercontent.com,gstatic.com,l.google.com";
+#define DEFAULT_SNISTR "googlevideo.com,ggpht.com,ytimg.com,youtube.com,play.google.com,youtu.be,googleapis.com,googleusercontent.com,gstatic.com,l.google.com"
+
+static const char defaul_snistr[] = DEFAULT_SNISTR;

 #endif /* YTB_CONFIG_H */
--- a/ipt_YTUNBLOCK.h
+++ b/ipt_YTUNBLOCK.h
@ -1,6 +0,0 @@
-#ifndef IPT_YTUNBLOCK_H
-#define IPT_YTUNBLOCK_H
-
-struct xt_ytunblock_tginfo {};
-
-#endif /* IPT_YTUNBLOCK_H */
--- a/iptk_YTUNBLOCK.c
+++ b/iptk_YTUNBLOCK.c
@ -1,341 +0,0 @@
-#define _GNU_SOURCE
-// Kernel module for youtubeUnblock.
-// Make with make kmake && sudo iptables -t mangle -D OUTPUT 1 && sudo make kreload && sudo iptables -t mangle -I OUTPUT -p tcp -j YTUNBLOCK
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/printk.h>
-#include <linux/mutex.h>
-#include <linux/socket.h>
-#include <linux/net.h>
-#include <linux/netfilter/x_tables.h>
-#include "ipt_YTUNBLOCK.h"
-
-#include "mangle.h"
-#include "config.h"
-#include "raw_replacements.h"
-
-MODULE_LICENSE("GPL");
-MODULE_VERSION("0.1");
-MODULE_AUTHOR("Vadim Vetrov <vetrovvd@gmail.com>");
-MODULE_DESCRIPTION("Linux kernel module for youtube unblock");
-
-static int rsfd;
-static struct socket *rawsocket;
-DEFINE_MUTEX(rslock);
-
-static int open_raw_socket(void) {
-	int ret = 0;
-	ret = sock_create(AF_INET, SOCK_RAW, IPPROTO_RAW, &rawsocket);
-
-	if (ret < 0) {
-		pr_alert("Unable to create raw socket\n");
-		goto err;
-	}
-
-	sockptr_t optval = {
-		.kernel = NULL,
-		.is_kernel = 1
-	};
-
-	int mark = RAWSOCKET_MARK;
-	optval.kernel = &mark;
-	ret = sock_setsockopt(rawsocket, SOL_SOCKET, SO_MARK, optval, sizeof(mark));
-	if (ret < 0)
-	{
-		pr_alert("setsockopt(SO_MARK, %d) failed\n", mark);
-		goto sr_err;
-	}
-	int one = 1;
-	optval.kernel = &one;
-
-	return 0;
-sr_err:
-	sock_release(rawsocket);
-err:
-	return ret;
-}
-
-static void close_raw_socket(void) {
-	sock_release(rawsocket);
-}
-
-#define AVAILABLE_MTU 1384
-
-static int send_raw_socket(const uint8_t *pkt, uint32_t pktlen) {
-	
-	if (pktlen > AVAILABLE_MTU) {
-		pr_warn("The packet is too big and may cause issues!");
-
-		__u32 buff1_size = pktlen;
-		__u32 buff2_size = pktlen;
-		__u8 *buff1 = kmalloc(pktlen, GFP_ATOMIC);
-		if (buff1 == NULL) return -1;
-		__u8 *buff2 = kmalloc(pktlen, GFP_ATOMIC);
-		if (buff2 == NULL) {
-			kfree(buff1);
-			return -1;
-		}
-
-		int ret;
-
-#if defined(USE_TCP_SEGMENTATION) || defined(RAWSOCK_TCP_FSTRAT)
-		if ((ret = tcp4_frag(pkt, pktlen, AVAILABLE_MTU-128, 
-			buff1, &buff1_size, buff2, &buff2_size)) < 0)
-			return ret;
-#elif defined(USE_IP_FRAGMENTATION) || defined(RAWSOCK_IP_FSTRAT)
-		if ((ret = ip4_frag(pkt, pktlen, AVAILABLE_MTU-128, 
-			buff1, &buff1_size, buff2, &buff2_size)) < 0)
-			return ret;
-#else
-		pr_warn("send_raw_socket: Packet is too big but fragmentation is disabled! "
-			"Pass -DRAWSOCK_TCP_FSTRAT or -DRAWSOCK_IP_FSTRAT as CFLAGS "
-			"To enable it only for raw socket\n");
-		return -EINVAL;
-#endif
-
-		int sent = 0;
-		ret = send_raw_socket(buff1, buff1_size);
-
-		if (ret >= 0) sent += ret;
-		else {
-			kfree(buff1);
-			kfree(buff2);
-			return ret;
-		}
-
-		kfree(buff1);
-
-		ret = send_raw_socket(buff2, buff2_size);
-		if (ret >= 0) sent += ret;
-		else {
-			kfree(buff2);
-			return ret;
-		}
-
-		kfree(buff2);
-
-		return sent;
-	}
-
-	struct iphdr *iph;
-
-	int ret;
-	if ((ret = ip4_payload_split(
-	(uint8_t *)pkt, pktlen, &iph, NULL, NULL, NULL)) < 0) {
-		return ret;
-	}
-
-	struct sockaddr_in daddr = {
-		.sin_family = AF_INET,
-		.sin_port = 0,
-		.sin_addr = {
-			.s_addr = iph->daddr
-		}
-	};
-
-	struct msghdr msg;
-	struct kvec iov;
-	iov.iov_base = (__u8 *)pkt;
-	iov.iov_len = pktlen;
-	iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, 1);
-
-	msg.msg_flags = 0;
-	msg.msg_name = &daddr;
-	msg.msg_namelen = sizeof(struct sockaddr_in);
-	msg.msg_control = NULL;
-	msg.msg_controllen = 0;
-
-	mutex_lock(&rslock);
-	ret = kernel_sendmsg(rawsocket, &msg, &iov, 1, pktlen);
-	mutex_unlock(&rslock);
-
-	return ret;
-}
-static unsigned int ykb_tg(struct sk_buff *skb, const struct xt_action_param *par) 
-{
-	if ((skb->mark & RAWSOCKET_MARK) == RAWSOCKET_MARK) 
-		return XT_CONTINUE;
-	
-	if (skb->head == NULL) return XT_CONTINUE;
-	
-	// TODO: Mallocs are bad!
-	uint32_t buflen = skb->len;
-	__u8 *buf = kmalloc(skb->len, GFP_ATOMIC);
-	if (buf == NULL) {
-		pr_err("Cannot alloc enough buffer space");
-		goto accept;
-	}
-	if (skb_copy_bits(skb, 0, buf, skb->len) < 0) {
-		pr_err("Unable copy bits\n");
-		goto ac_fkb;
-	}
-	struct iphdr *iph;
-	uint32_t iph_len;
-	struct tcphdr *tcph;
-	uint32_t tcph_len;
-	__u8 *payload;
-	uint32_t plen;
-
-	int ret = tcp4_payload_split(buf, buflen, &iph, &iph_len, 
-		    &tcph, &tcph_len, &payload, &plen);
-
-	if (ret < 0) 
-		goto ac_fkb;
-
-	struct verdict vrd = analyze_tls_data(payload, plen);
-
-	if (vrd.gvideo_hello) {
-		int ret;
-		pr_info("Googlevideo detected\n");
-
-		ip4_set_checksum(iph);
-		tcp4_set_checksum(tcph, iph);
-
-		uint32_t f1len = skb->len;
-		uint32_t f2len = skb->len;
-		__u8 *frag1 = kmalloc(f1len, GFP_ATOMIC);
-		if (!frag1) {
-			pr_err("Cannot alloc enough gv frag1 buffer space");
-			goto ac_fkb;
-		}
-		__u8 *frag2 = kmalloc(f2len, GFP_ATOMIC);
-		if (!frag2) {
-			pr_err("Cannot alloc enough gv frag1 buffer space");
-			kfree(frag1);
-			goto ac_fkb;
-		}
-
-
-#ifdef FAKE_SNI
-		uint32_t fksn_len = FAKE_SNI_MAXLEN;
-		__u8 *fksn_buf = kmalloc(fksn_len, GFP_ATOMIC);
-		if (!fksn_buf) {
-			pr_err("Cannot alloc enough gksn buffer space");
-			goto fallback;
-		}
-		
-		ret = gen_fake_sni(iph, tcph, fksn_buf, &fksn_len);
-		if (ret < 0) {
-			pr_err("Cannot alloc enough gksn buffer space");
-			goto fksn_fb;
-		}
-#endif
-
-#if defined(USE_TCP_SEGMENTATION)
-		size_t ipd_offset = vrd.sni_offset;
-		size_t mid_offset = ipd_offset + vrd.sni_len / 2;
-
-
-		if ((ret = tcp4_frag(buf, skb->len, 
-			 mid_offset, frag1, &f1len, frag2, &f2len)) < 0) {
-			pr_err("tcp4_frag: %d", ret);
-			goto fksn_fb;
-		}
-#elif defined(USE_IP_FRAGMENTATION)
-		size_t ipd_offset = tcph_len + vrd.sni_offset;
-		size_t mid_offset = ipd_offset + vrd.sni_len / 2;
-		mid_offset += 8 - mid_offset % 8;
-
-		if ((ret = ip4_frag(buf, skb->len, 
-			 mid_offset, frag1, &f1len, frag2, &f2len)) < 0) {
-			pr_err("ip4_frag: %d", ret);
-			goto fksn_fb;
-		}
-#endif
-
-#ifdef FAKE_SNI
-		ret = send_raw_socket(fksn_buf, fksn_len);
-		if (ret < 0) {
-			pr_err("fksn_send: %d", ret);
-			goto fksn_fb;
-		}
-#endif
-
-#if defined(USE_NO_FRAGMENTATION)
-#ifdef SEG2_DELAY
-#error "SEG2_DELAY is incompatible with NO FRAGMENTATION"
-#endif
-		ret = send_raw_socket(buf, buflen);
-		if (ret < 0) {
-			pr_err("nofrag_send: %d", ret);
-		}
-		goto fksn_fb;
-#endif
-
-		ret = send_raw_socket(frag2, f2len);
-		if (ret < 0) {
-			pr_err("raw frag2 send: %d", ret);
-			goto fksn_fb;
-		}
-
-#ifdef SEG2_DELAY
-#error "Seg2 delay is unsupported yet for kmod"
-#else
-		ret = send_raw_socket(frag1, f1len);
-		if (ret < 0) {
-			pr_err("raw frag1 send: %d", ret);
-			goto fksn_fb;
-		}
-#endif
-
-fksn_fb:
-#ifdef FAKE_SNI
-		kfree(fksn_buf);
-#endif 
-fallback:
-#ifndef SEG2_DELAY
-		kfree(frag1);
-#endif
-		kfree(frag2);
-		kfree(buf);
-		kfree_skb(skb);
-		return NF_STOLEN;
-	}
-ac_fkb:
-	kfree(buf);
-accept:
-	return XT_CONTINUE;
-}
-
-static int ykb_chk(const struct xt_tgchk_param *par) {
-	return 0;
-}
-
-
-static struct xt_target ykb_tg_reg __read_mostly = {
-	.name		= "YTUNBLOCK",
-	.target		= ykb_tg,
-	.table		= "mangle",
-	.hooks		= (1 << NF_INET_LOCAL_OUT) | (1 << NF_INET_FORWARD), 
-	.targetsize	= sizeof(struct xt_ytunblock_tginfo),
-	.proto		= IPPROTO_TCP,
-	.family		= NFPROTO_IPV4,
-	.checkentry	= ykb_chk,
-	.me		= THIS_MODULE,
-};
-
-static int __init ykb_init(void) {
-	int ret = 0;
-
-	ret = open_raw_socket();
-	if (ret < 0) goto err;
-
-	ret = xt_register_target(&ykb_tg_reg);
-	if (ret < 0) goto close_rawsocket;
-
-	pr_info("youtubeUnblock kernel module started.\n");
-	return 0;
-close_rawsocket:
-	close_raw_socket();
-err:
-	return ret;
-}
-
-static void __exit ykb_destroy(void) {
-	xt_unregister_target(&ykb_tg_reg);
-	close_raw_socket();
-	pr_info("youtubeUnblock kernel module destroyed.\n");
-}
-
-module_init(ykb_init);
-module_exit(ykb_destroy);
--- a/kargs.c
+++ b/kargs.c
@ -0,0 +1,374 @@
+#include "config.h"
+#include "raw_replacements.h"
+#include "types.h"
+#include <linux/moduleparam.h>
+
+#define STR_MAXLEN 2048
+
+struct config_t config = {
+	.frag_sni_reverse = 1,
+	.frag_sni_faked = 0,
+	.fragmentation_strategy = FRAGMENTATION_STRATEGY,
+	.faking_strategy = FAKING_STRATEGY,
+	.faking_ttl = FAKE_TTL,
+	.fake_sni = 1,
+	.fake_sni_seq_len = 1,
+	.frag_middle_sni = 1,
+	.frag_sni_pos = 1,
+	.use_ipv6 = 1,
+	.fakeseq_offset = 10000,
+	.mark = DEFAULT_RAWSOCKET_MARK,
+	.synfake = 0,
+	.synfake_len = 0,
+
+	.sni_detection = SNI_DETECTION_PARSE,
+
+#ifdef SEG2_DELAY
+	.seg2_delay = SEG2_DELAY,
+#else
+	.seg2_delay = 0,
+#endif
+
+#ifdef USE_GSO
+	.use_gso = 1,
+#else
+	.use_gso = false,
+#endif
+
+#ifdef DEBUG
+	.verbose = 2,
+#else
+	.verbose = 1,
+#endif
+
+	.domains_str = defaul_snistr,
+	.domains_strlen = sizeof(defaul_snistr),
+
+	.queue_start_num = DEFAULT_QUEUE_NUM,
+	.fake_sni_pkt = fake_sni_old,
+	.fake_sni_pkt_sz = sizeof(fake_sni_old) - 1, // - 1 for null-terminator
+};
+
+static int unumeric_set(const char *val, const struct kernel_param *kp) {
+	int n = 0, ret;
+	ret = kstrtoint(val, 10, &n);
+	if (ret != 0 || n < 0)
+		return -EINVAL;
+
+
+	return param_set_int(val, kp);
+}
+
+static int boolean_set(const char *val, const struct kernel_param *kp) {
+	int n = 0, ret;
+	ret = kstrtoint(val, 10, &n);
+	if (ret != 0 || (n != 0 && n != 1))
+		return -EINVAL;
+
+	return param_set_int(val, kp);
+}
+
+static int inverse_boolean_set(const char *val, const struct kernel_param *kp) {
+	int n = 0, ret;
+	ret = kstrtoint(val, 10, &n);
+	if (ret != 0 || (n != 0 && n != 1))
+		return -EINVAL;
+
+	n = !n;
+	if (kp->arg == NULL) 
+		return -EINVAL;
+
+	*(int *)kp->arg = n;
+	return 0;
+}
+
+static int inverse_boolean_get(char *buffer, const struct kernel_param *kp) {
+	if (*(int *)kp->arg == 0) {
+		buffer[0] = '1';
+	} else {
+		buffer[0] = '0';
+	}
+	buffer[1] = '\0';
+	return strlen(buffer);
+}
+
+static const struct kernel_param_ops unumeric_parameter_ops = {
+	.set = unumeric_set,
+	.get = param_get_int
+};
+
+static const struct kernel_param_ops boolean_parameter_ops = {
+	.set = boolean_set,
+	.get = param_get_int
+};
+
+static const struct kernel_param_ops inverse_boolean_ops = {
+	.set = inverse_boolean_set,
+	.get = inverse_boolean_get,
+};
+
+module_param_cb(fake_sni, &boolean_parameter_ops, &config.fake_sni, 0664);
+module_param_cb(fake_sni_seq_len, &unumeric_parameter_ops, &config.fake_sni_seq_len, 0664);
+module_param_cb(faking_ttl, &unumeric_parameter_ops, &config.faking_ttl, 0664);
+module_param_cb(fake_seq_offset, &unumeric_parameter_ops, &config.fakeseq_offset, 0664);
+module_param_cb(frag_sni_reverse, &unumeric_parameter_ops, &config.frag_sni_reverse, 0664);
+module_param_cb(frag_sni_faked, &boolean_parameter_ops, &config.frag_sni_faked, 0664);
+module_param_cb(frag_middle_sni, &boolean_parameter_ops, &config.frag_middle_sni, 0664);
+module_param_cb(frag_sni_pos, &unumeric_parameter_ops, &config.frag_sni_pos, 0664);
+module_param_cb(fk_winsize, &unumeric_parameter_ops, &config.fk_winsize, 0664);
+module_param_cb(synfake, &boolean_parameter_ops, &config.synfake, 0664);
+module_param_cb(synfake_len, &unumeric_parameter_ops, &config.synfake_len, 0664);
+module_param_cb(packet_mark, &unumeric_parameter_ops, &config.mark, 0664);
+
+static int sni_domains_set(const char *val, const struct kernel_param *kp) {
+	size_t len;
+	int ret;
+
+	len = strnlen(val, STR_MAXLEN + 1);
+	if (len == STR_MAXLEN + 1) {
+		pr_err("%s: string parameter too long\n", kp->name);
+		return -ENOSPC;
+	}
+
+	if (len >= 1 && val[len - 1] == '\n') {
+		len--;
+	}
+
+	ret = param_set_charp(val, kp);
+
+	if (ret < 0) {
+		config.domains_strlen = 0;
+	} else {
+		config.domains_strlen = len;
+		if (len == 3 && !strncmp(val, "all", len)) {
+			config.all_domains = 1;
+		} else {
+			config.all_domains = 0;
+		}
+	}
+
+
+	return ret;
+}
+
+static const struct kernel_param_ops sni_domains_ops = {
+	.set = sni_domains_set,
+	.get = param_get_charp,
+};
+
+module_param_cb(sni_domains, &sni_domains_ops, &config.domains_str, 0664);
+
+static int exclude_domains_set(const char *val, const struct kernel_param *kp) {
+	size_t len;
+	int ret;
+
+	len = strnlen(val, STR_MAXLEN + 1);
+	if (len == STR_MAXLEN + 1) {
+		pr_err("%s: string parameter too long\n", kp->name);
+		return -ENOSPC;
+	}
+
+	ret = param_set_charp(val, kp);
+
+	if (ret < 0) {
+		config.exclude_domains_strlen = 0;
+	} else {
+		config.exclude_domains_strlen = len;
+	}
+
+	return ret;
+}
+
+static const struct kernel_param_ops exclude_domains_ops = {
+	.set = exclude_domains_set,
+	.get = param_get_charp,
+};
+
+module_param_cb(exclude_domains, &exclude_domains_ops, &config.exclude_domains_str, 0664);
+
+module_param_cb(no_ipv6, &inverse_boolean_ops, &config.use_ipv6, 0664);
+module_param_cb(silent, &inverse_boolean_ops, &config.verbose, 0664);
+module_param_cb(quic_drop, &boolean_parameter_ops, &config.quic_drop, 0664);
+
+static int verbose_trace_set(const char *val, const struct kernel_param *kp) {
+	int n = 0, ret;
+	ret = kstrtoint(val, 10, &n);
+	if (ret != 0 || (n != 0 && n != 1))
+		return -EINVAL;
+
+	if (n) {
+		n = VERBOSE_TRACE;
+	} else {
+		n = VERBOSE_DEBUG;
+	}
+	if (kp->arg == NULL) 
+		return -EINVAL;
+
+	*(int *)kp->arg = n;
+	return 0;
+}
+
+static const struct kernel_param_ops verbose_trace_ops = {
+	.set = verbose_trace_set,
+	.get = param_get_int,
+};
+
+module_param_cb(trace, &verbose_trace_ops, &config.verbose, 0664);
+
+static int frag_strat_set(const char *val, const struct kernel_param *kp) {
+	size_t len;
+
+	len = strnlen(val, STR_MAXLEN + 1);
+	if (len == STR_MAXLEN + 1) {
+		pr_err("%s: string parameter too long\n", kp->name);
+		return -ENOSPC;
+	}
+
+	if (len >= 1 && val[len - 1] == '\n') {
+		len--;
+	}
+
+	if (strncmp(val, "tcp", len) == 0) {
+		*(int *)kp->arg = FRAG_STRAT_TCP;
+	} else if (strncmp(val, "ip", len) == 0) {
+		*(int *)kp->arg = FRAG_STRAT_IP;
+	} else if (strncmp(val, "none", len) == 0) {
+		*(int *)kp->arg = FRAG_STRAT_NONE;
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int frag_strat_get(char *buffer, const struct kernel_param *kp) {
+	switch (*(int *)kp->arg) {
+		case FRAG_STRAT_TCP:
+			strcpy(buffer, "tcp\n");
+			break;
+		case FRAG_STRAT_IP:
+			strcpy(buffer, "ip\n");
+			break;
+		case FRAG_STRAT_NONE:
+			strcpy(buffer, "none\n");
+			break;
+		default:
+			strcpy(buffer, "unknown\n");
+	}
+
+	return strlen(buffer);
+}
+
+static const struct kernel_param_ops frag_strat_ops = {
+	.set = frag_strat_set,
+	.get = frag_strat_get,
+};
+
+module_param_cb(fragmentation_strategy, &frag_strat_ops, &config.fragmentation_strategy, 0664);
+
+static int fake_strat_set(const char *val, const struct kernel_param *kp) {
+	size_t len;
+
+	len = strnlen(val, STR_MAXLEN + 1);
+	if (len == STR_MAXLEN + 1) {
+		pr_err("%s: string parameter too long\n", kp->name);
+		return -ENOSPC;
+	}
+
+	if (len >= 1 && val[len - 1] == '\n') {
+		len--;
+	}
+
+	if (strncmp(val, "randseq", len) == 0) {
+		*(int *)kp->arg = FAKE_STRAT_RAND_SEQ;
+	} else if (strncmp(val, "ttl", len) == 0) {
+		*(int *)kp->arg = FAKE_STRAT_TTL;
+	} else if (strncmp(val, "tcp_check", len) == 0) {
+		*(int *)kp->arg = FAKE_STRAT_TCP_CHECK;
+	} else if (strncmp(val, "pastseq", len) == 0) {
+		*(int *)kp->arg = FAKE_STRAT_PAST_SEQ;
+	} else if (strncmp(val, "md5sum", len) == 0) {
+		*(int *)kp->arg = FAKE_STRAT_TCP_MD5SUM;
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int fake_strat_get(char *buffer, const struct kernel_param *kp) {
+	switch (*(int *)kp->arg) {
+		case FAKE_STRAT_RAND_SEQ:
+			strcpy(buffer, "randseq\n");
+			break;
+		case FAKE_STRAT_TTL:
+			strcpy(buffer, "ttl\n");
+			break;
+		case FAKE_STRAT_TCP_CHECK:
+			strcpy(buffer, "tcp_check\n");
+			break;
+		case FAKE_STRAT_PAST_SEQ:
+			strcpy(buffer, "pastseq\n");
+			break;
+		case FAKE_STRAT_TCP_MD5SUM:
+			strcpy(buffer, "md5sum\n");
+			break;
+		default:
+			strcpy(buffer, "unknown\n");
+	}
+
+	return strlen(buffer);
+}
+
+static const struct kernel_param_ops fake_strat_ops = {
+	.set = fake_strat_set,
+	.get = fake_strat_get,
+};
+
+module_param_cb(faking_strategy, &fake_strat_ops, &config.faking_strategy, 0664);
+
+static int sni_detection_set(const char *val, const struct kernel_param *kp) {
+	size_t len;
+
+	len = strnlen(val, STR_MAXLEN + 1);
+	if (len == STR_MAXLEN + 1) {
+		pr_err("%s: string parameter too long\n", kp->name);
+		return -ENOSPC;
+	}
+
+	if (len >= 1 && val[len - 1] == '\n') {
+		len--;
+	}
+
+	if (strncmp(val, "parse", len) == 0) {
+		*(int *)kp->arg = SNI_DETECTION_PARSE;
+	} else if (strncmp(val, "brute", len) == 0) {
+		*(int *)kp->arg = SNI_DETECTION_BRUTE;
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int sni_detection_get(char *buffer, const struct kernel_param *kp) {
+	switch (*(int *)kp->arg) {
+		case SNI_DETECTION_PARSE:
+			strcpy(buffer, "parse\n");
+			break;
+		case SNI_DETECTION_BRUTE:
+			strcpy(buffer, "brute\n");
+			break;
+		default:
+			strcpy(buffer, "unknown\n");
+	}
+
+	return strlen(buffer);
+}
+
+static const struct kernel_param_ops sni_detection_ops = {
+	.set = sni_detection_set,
+	.get = sni_detection_get,
+};
+
+module_param_cb(sni_detection, &sni_detection_ops, &config.sni_detection, 0664);
--- a/kmake.mk
+++ b/kmake.mk
@ -7,36 +7,23 @@ LD	:= ld
 CFLAGS	:=
 LDFLAGS	:=

-IPT_CFLAGS := -Wall -Wpedantic -O2
+KERNEL_BUILDER_MAKEDIR:=/lib/modules/$(shell uname -r)/build

 .PHONY: kmake kload kunload kreload kclean kmclean xclean
-kmake: kmod xmod
+kmake: kmod

 kmod:
-	$(MAKE) -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
-
-xmod: libipt_YTUNBLOCK.so
-
-libipt_YTUNBLOCK.so: libipt_YTUNBLOCK.o
-	$(CCLD) -shared -fPIC ${IPT_CFLAGS} -o $@ $^;
-
-libipt_YTUNBLOCK.o: libipt_YTUNBLOCK.c
-	$(CC) ${IPT_CFLAGS} -D_INIT=lib$*_init -fPIC -c -o $@ $<;
+	$(MAKE) -C $(KERNEL_BUILDER_MAKEDIR) M=$(PWD) modules

 kload:
-	insmod ipt_YTUNBLOCK.ko
-	cp ./libipt_YTUNBLOCK.so /usr/lib/xtables/
+	insmod kyoutubeUnblock.ko

 kunload:
-	-rmmod ipt_YTUNBLOCK
-	-/bin/rm /usr/lib/xtables/libipt_YTUNBLOCK.so
+	-rmmod kyoutubeUnblock

 kreload: kunload kload

-kclean: xtclean kmclean
+kclean: kmclean

 kmclean:
-	-$(MAKE) -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
-
-xtclean:
-	-/bin/rm -f libipt_YTUNBLOCK.so libipt_YTUNBLOCK.o
+	-$(MAKE) -C $(KERNEL_BUILDER_MAKEDIR) M=$(PWD) clean
--- a/kmod_utils.c
+++ b/kmod_utils.c
@ -0,0 +1,226 @@
+#ifndef KERNEL_SPACE
+#error "You are trying to compile the kernel module not in the kernel space"
+#endif
+#include "kmod_utils.h"
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/socket.h>
+#include <linux/net.h>
+
+#include "config.h"
+#include "utils.h"
+#include "logging.h"
+
+static struct socket *rawsocket;
+
+static struct socket *raw6socket;
+
+
+int open_raw_socket(void) {
+	int ret = 0;
+	ret = sock_create(AF_INET, SOCK_RAW, IPPROTO_RAW, &rawsocket);
+
+	if (ret < 0) {
+		pr_alert("Unable to create raw socket\n");
+		goto err;
+	}
+
+	// That's funny, but this is how it is done in the kernel
+	// https://elixir.bootlin.com/linux/v3.17.7/source/net/core/sock.c#L916
+	rawsocket->sk->sk_mark=config.mark;
+
+	return 0;
+
+err:
+	return ret;
+}
+
+void close_raw_socket(void) {
+	sock_release(rawsocket);
+}
+
+static int send_raw_ipv4(const uint8_t *pkt, uint32_t pktlen) {
+	int ret = 0;
+	if (pktlen > AVAILABLE_MTU) return -ENOMEM;
+
+	struct iphdr *iph;
+
+	if ((ret = ip4_payload_split(
+	(uint8_t *)pkt, pktlen, &iph, NULL, NULL, NULL)) < 0) {
+		return ret;
+	}
+
+	struct sockaddr_in daddr = {
+		.sin_family = AF_INET,
+		.sin_port = 0,
+		.sin_addr = {
+			.s_addr = iph->daddr
+		}
+	};
+
+	struct msghdr msg;
+	struct kvec iov;
+
+	memset(&msg, 0, sizeof(msg));
+
+	iov.iov_base = (__u8 *)pkt;
+	iov.iov_len = pktlen;
+
+	msg.msg_flags = 0;
+	msg.msg_name = &daddr;
+	msg.msg_namelen = sizeof(struct sockaddr_in);
+	msg.msg_control = NULL;
+	msg.msg_controllen = 0;
+
+
+	ret = kernel_sendmsg(rawsocket, &msg, &iov, 1, pktlen);
+
+	return ret;
+}
+
+int open_raw6_socket(void) {
+	int ret = 0;
+	ret = sock_create(AF_INET6, SOCK_RAW, IPPROTO_RAW, &raw6socket);
+
+	if (ret < 0) {
+		pr_alert("Unable to create raw socket\n");
+		goto err;
+	}
+
+	// That's funny, but this is how it is done in the kernel
+	// https://elixir.bootlin.com/linux/v3.17.7/source/net/core/sock.c#L916
+	raw6socket->sk->sk_mark=config.mark;
+
+	return 0;
+
+err:
+	return ret;
+}
+
+void close_raw6_socket(void) {
+	sock_release(raw6socket);
+}
+
+int send_raw_ipv6(const uint8_t *pkt, uint32_t pktlen) {
+	int ret = 0;
+	if (pktlen > AVAILABLE_MTU) return -ENOMEM;
+
+	struct ip6_hdr *iph;
+
+	if ((ret = ip6_payload_split(
+	(uint8_t *)pkt, pktlen, &iph, NULL, NULL, NULL)) < 0) {
+		return ret;
+	}
+
+	struct sockaddr_in6 daddr = {
+		.sin6_family = AF_INET6,
+		/* Always 0 for raw socket */
+		.sin6_port = 0,
+		.sin6_addr = iph->ip6_dst
+	};
+
+	struct kvec iov;
+	struct msghdr msg;
+	memset(&msg, 0, sizeof(msg));
+
+	iov.iov_base = (__u8 *)pkt;
+	iov.iov_len = pktlen;
+
+	msg.msg_flags = 0;
+	msg.msg_name = &daddr;
+	msg.msg_namelen = sizeof(struct sockaddr_in6);
+	msg.msg_control = NULL;
+	msg.msg_controllen = 0;
+
+	ret = kernel_sendmsg(raw6socket, &msg, &iov, 1, pktlen);
+
+	return ret;
+}
+
+int send_raw_socket(const uint8_t *pkt, uint32_t pktlen) {
+	int ret;
+
+	if (pktlen > AVAILABLE_MTU) {
+		lgdebug("The packet is too big and may cause issues!");
+
+		NETBUF_ALLOC(buff1, MAX_PACKET_SIZE);
+		if (!NETBUF_CHECK(buff1)) {
+			lgerror("Allocation error", -ENOMEM);
+			return -ENOMEM;
+		}
+		NETBUF_ALLOC(buff2, MAX_PACKET_SIZE);
+		if (!NETBUF_CHECK(buff2)) {
+			lgerror("Allocation error", -ENOMEM);
+			NETBUF_FREE(buff2);
+			return -ENOMEM;
+		}
+		uint32_t buff1_size = MAX_PACKET_SIZE;
+		uint32_t buff2_size = MAX_PACKET_SIZE;
+
+		switch (config.fragmentation_strategy) {
+			case FRAG_STRAT_TCP:
+				if ((ret = tcp_frag(pkt, pktlen, AVAILABLE_MTU-128,
+					buff1, &buff1_size, buff2, &buff2_size)) < 0) {
+
+					goto erret_lc;
+				}
+				break;
+			case FRAG_STRAT_IP:
+				if ((ret = ip4_frag(pkt, pktlen, AVAILABLE_MTU-128,
+					buff1, &buff1_size, buff2, &buff2_size)) < 0) {
+
+					goto erret_lc;
+				}
+				break;
+			default:
+				pr_info("send_raw_socket: Packet is too big but fragmentation is disabled!");
+				ret = -EINVAL;
+				goto erret_lc;
+		}
+
+		int sent = 0;
+		ret = send_raw_socket(buff1, buff1_size);
+
+		if (ret >= 0) sent += ret;
+		else {
+			goto erret_lc;
+		}
+
+		ret = send_raw_socket(buff2, buff2_size);
+		if (ret >= 0) sent += ret;
+		else {
+			goto erret_lc;
+		}
+
+		NETBUF_FREE(buff1);
+		NETBUF_FREE(buff2);
+		return sent;
+erret_lc:
+		NETBUF_FREE(buff1);
+		NETBUF_FREE(buff2);
+		return ret;
+	}
+	
+	int ipvx = netproto_version(pkt, pktlen);
+
+	if (ipvx == IP4VERSION) 
+		return send_raw_ipv4(pkt, pktlen);
+
+	else if (ipvx == IP6VERSION) 
+		return send_raw_ipv6(pkt, pktlen);
+
+	printf("proto version %d is unsupported\n", ipvx);
+	return -EINVAL;
+}
+
+void delay_packet_send(const unsigned char *data, unsigned int data_len, unsigned int delay_ms) {
+	pr_info("delay_packet_send won't work on current youtubeUnblock version");
+	send_raw_socket(data, data_len);
+}
+
+struct instance_config_t instance_config = {
+	.send_raw_packet = send_raw_socket,
+	.send_delayed_packet = delay_packet_send,
+};
--- a/kmod_utils.h
+++ b/kmod_utils.h
@ -0,0 +1,14 @@
+#include "types.h"
+
+#ifndef KMOD_UTILS_H
+#define KMOD_UTILS_H
+
+int open_raw_socket(void);
+void close_raw_socket(void);
+int open_raw6_socket(void);
+void close_raw6_socket(void);
+int send_raw_ipv6(const uint8_t *pkt, uint32_t pktlen);
+int send_raw_socket(const uint8_t *pkt, uint32_t pktlen);
+void delay_packet_send(const unsigned char *data, unsigned int data_len, unsigned int delay_ms);
+
+#endif /* KMOD_UTILS_H */
--- a/kytunblock.c
+++ b/kytunblock.c
@ -0,0 +1,147 @@
+#include "nf_wrapper.h"
+#ifndef KERNEL_SPACE
+#error "You are trying to compile the kernel module not in the kernel space"
+#endif
+// Kernel module for youtubeUnblock.
+// Make with make kmake && sudo iptables -t mangle -D OUTPUT 1 && sudo make kreload && sudo iptables -t mangle -I OUTPUT -p tcp -j YTUNBLOCK
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/socket.h>
+#include <linux/net.h>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter_ipv6.h>
+
+#include "mangle.h"
+#include "config.h"
+#include "utils.h"
+#include "logging.h"
+#include "kmod_utils.h"
+
+MODULE_LICENSE("GPL");
+MODULE_VERSION("0.3.2");
+MODULE_AUTHOR("Vadim Vetrov <vetrovvd@gmail.com>");
+MODULE_DESCRIPTION("Linux kernel module for youtube unblock");
+
+static NF_CALLBACK(ykb_nf_hook, skb) {
+	int ret;
+
+	if ((skb->mark & config.mark) == config.mark) 
+		goto accept;
+	
+	if (skb->head == NULL) 
+		goto accept;
+	
+	if (skb->len > MAX_PACKET_SIZE)
+		goto accept;
+
+	ret = skb_linearize(skb);
+	if (ret < 0) {
+		lgerror("Cannot linearize", ret);
+		goto accept;
+	}
+
+	int vrd = process_packet(skb->data, skb->len);
+
+	switch(vrd) {
+		case PKT_ACCEPT:
+			goto accept;
+		case PKT_DROP:
+			goto drop;
+	}
+
+accept:
+	return NF_ACCEPT;
+drop:
+	kfree_skb(skb);
+	return NF_STOLEN;
+}
+
+
+static struct nf_hook_ops ykb_nf_reg __read_mostly = {
+	.hook		= ykb_nf_hook,
+	.pf		= NFPROTO_IPV4,
+	.hooknum	= NF_INET_POST_ROUTING,
+	.priority	= NF_IP_PRI_MANGLE,
+};
+
+static struct nf_hook_ops ykb6_nf_reg __read_mostly = {
+	.hook		= ykb_nf_hook,
+	.pf		= NFPROTO_IPV6,
+	.hooknum	= NF_INET_POST_ROUTING,
+	.priority	= NF_IP6_PRI_MANGLE,
+};
+
+static int __init ykb_init(void) {
+	int ret = 0;
+
+	ret = open_raw_socket();
+	if (ret < 0) goto err;
+
+
+	if (config.use_ipv6) {
+		ret = open_raw6_socket();
+		if (ret < 0) goto close_rawsocket;
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,13,0)
+		struct net *n;
+		for_each_net(n) {
+			ret = nf_register_net_hook(n, &ykb6_nf_reg);
+			if (ret < 0) 
+				lgerror("bad rat",ret);
+		}
+#else
+		nf_register_hook(&ykb6_nf_reg);
+#endif
+	}
+
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,13,0)
+	struct net *n;
+
+	for_each_net(n) {
+		ret = nf_register_net_hook(n, &ykb_nf_reg);
+		if (ret < 0) 
+			lgerror("bad rat",ret);
+	}
+#else
+	nf_register_hook(&ykb_nf_reg);
+#endif
+
+	pr_info("youtubeUnblock kernel module started.\n");
+	return 0;
+
+close_rawsocket:
+	close_raw_socket();
+err:
+	return ret;
+}
+
+static void __exit ykb_destroy(void) {
+	if (config.use_ipv6) {
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,13,0)
+		struct net *n;
+		for_each_net(n)
+			nf_unregister_net_hook(n, &ykb6_nf_reg);
+#else
+		nf_unregister_hook(&ykb6_nf_reg);
+#endif
+		close_raw6_socket();
+	}
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,13,0)
+	struct net *n;
+	for_each_net(n)
+		nf_unregister_net_hook(n, &ykb_nf_reg);
+#else
+	nf_unregister_hook(&ykb_nf_reg);
+#endif
+
+	close_raw_socket();
+	pr_info("youtubeUnblock kernel module destroyed.\n");
+}
+
+module_init(ykb_init);
+module_exit(ykb_destroy);
--- a/libipt_YTUNBLOCK.c
+++ b/libipt_YTUNBLOCK.c
@ -1,26 +0,0 @@
-// Used to register target in iptables
-#include <stdio.h>
-#include <xtables.h>
-
-#include <linux/netfilter_ipv4/ip_tables.h>
-#include "ipt_YTUNBLOCK.h"
-
-#define _init __attribute__((constructor)) _INIT
-#define __maybe_unused __attribute__((__unused__))
-
-static void YTKB_help(void) {
-	printf("Youtube Unblock - bypass youtube slowdown DPI in Russia\n");
-}
-
-static struct xtables_target ykb_tg_reg = {
-	.name           = "YTUNBLOCK",
-	.version        = XTABLES_VERSION,
-	.family         = NFPROTO_IPV4,
-	.size           = XT_ALIGN(sizeof(struct xt_ytunblock_tginfo)),
-	.userspacesize  = XT_ALIGN(sizeof(struct xt_ytunblock_tginfo)),
-	.help           = YTKB_help,
-};
-
-void _init(void) {
-    xtables_register_target(&ykb_tg_reg);
-}
--- a/logging.h
+++ b/logging.h
@ -5,11 +5,12 @@
 #define LOG_LEVEL (config.verbose)

 #ifdef KERNEL_SPACE
-#include <linux/printk.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
 #define printf pr_info
 #define perror pr_err
 #define lgerror(msg, ret, ...) __extension__ ({		\
-	printf(msg ": %d\n", ##__VA_ARGS__, ret);	\
+	pr_err(msg ": %d\n", ##__VA_ARGS__, ret);	\
 })
 #else
 #include <stdio.h> // IWYU pragma: export
--- a/mangle.c
+++ b/mangle.c
@ -6,7 +6,7 @@
 #include "quic.h"
 #include "logging.h"

-#ifndef KERNEL_SCOPE
+#ifndef KERNEL_SPACE
 #include <stdlib.h>
 #endif

@ -25,6 +25,7 @@ int process_packet(const uint8_t *raw_payload, uint32_t raw_payload_len) {
 	int ipver = netproto_version(raw_payload, raw_payload_len);
 	int ret;

+
 	if (ipver == IP4VERSION) {
 		ret = ip4_payload_split((uint8_t *)raw_payload, raw_payload_len,
 			 (struct iphdr **)&iph, &iph_len, 
@ -33,7 +34,7 @@ int process_packet(const uint8_t *raw_payload, uint32_t raw_payload_len) {
 		if (ret < 0)
 			goto accept;

-		transport_proto = iph ->protocol;
+		transport_proto = iph->protocol;

 	} else if (ipver == IP6VERSION && config.use_ipv6) {
 		ret = ip6_payload_split((uint8_t *)raw_payload, raw_payload_len,
@ -43,7 +44,7 @@ int process_packet(const uint8_t *raw_payload, uint32_t raw_payload_len) {
 		if (ret < 0)
 			goto accept;

-		transport_proto = ip6h->ip6_ctlun.ip6_un1.ip6_un1_nxt;
+		transport_proto = ip6h->ip6_nxt;

 	} else {
 		lgtracemsg("Unknown layer 3 protocol version: %d", ipver);
@ -55,15 +56,13 @@ int process_packet(const uint8_t *raw_payload, uint32_t raw_payload_len) {
 	case IPPROTO_TCP:
 		return process_tcp_packet(raw_payload, raw_payload_len);
 	case IPPROTO_UDP:
-		return process_udp4_packet(raw_payload, raw_payload_len);
+		return process_udp_packet(raw_payload, raw_payload_len);
 	default:
 		goto accept;
 	}
 	
 accept:
 	return PKT_ACCEPT;
-drop:
-	return PKT_DROP;
 }

 int process_tcp_packet(const uint8_t *raw_payload, uint32_t raw_payload_len) {
@ -74,6 +73,7 @@ int process_tcp_packet(const uint8_t *raw_payload, uint32_t raw_payload_len) {
 	const uint8_t *data;
 	uint32_t dlen;

+
 	int ipxv = netproto_version(raw_payload, raw_payload_len);

 	lgtrace_start("TCP");
@ -91,7 +91,13 @@ int process_tcp_packet(const uint8_t *raw_payload, uint32_t raw_payload_len) {

 	if (tcph->syn && config.synfake) {
 		lgtrace_addp("TCP syn alter");
-		uint8_t payload[MAX_PACKET_SIZE];
+
+		NETBUF_ALLOC(payload, MAX_PACKET_SIZE);
+		if (!NETBUF_CHECK(payload)) {
+			lgerror("Allocation error", -ENOMEM);
+			goto accept;
+		}
+
 		memcpy(payload, ipxh, iph_len);
 		memcpy(payload + iph_len, tcph, tcph_len);
 		uint32_t fake_len = config.fake_sni_pkt_sz;
@ -110,32 +116,40 @@ int process_tcp_packet(const uint8_t *raw_payload, uint32_t raw_payload_len) {
 			set_tcp_checksum(tcph, iph, iph_len);
 		} else if (ipxv == IP6VERSION) {
 			struct ip6_hdr *ip6h = (struct ip6_hdr *)payload;
-			ip6h->ip6_ctlun.ip6_un1.ip6_un1_plen = 
-				ntohs(tcph_len + fake_len);
+			ip6h->ip6_plen = ntohs(tcph_len + fake_len);
 			set_ip_checksum(ip6h, iph_len);
 			set_tcp_checksum(tcph, ip6h, iph_len);
 		}


-
 		ret = instance_config.send_raw_packet(payload, iph_len + tcph_len + fake_len);
 		if (ret < 0) {
 			lgerror("send_syn_altered", ret);
+
+			NETBUF_FREE(payload);
 			goto accept;
 		}
 		lgtrace_addp("rawsocket sent %d", ret);
+
+		NETBUF_FREE(payload);
 		goto drop;
 	}

 	if (tcph->syn) goto accept;

 	struct tls_verdict vrd = analyze_tls_data(data, dlen);
+	lgtrace_addp("Analyzed, %d", vrd.target_sni);

 	if (vrd.target_sni) {
 		lgdebugmsg("Target SNI detected: %.*s", vrd.sni_len, data + vrd.sni_offset);

-		uint8_t payload[MAX_PACKET_SIZE];
 		uint32_t payload_len = raw_payload_len;
+		NETBUF_ALLOC(payload, MAX_PACKET_SIZE);
+		if (!NETBUF_CHECK(payload)) {
+			lgerror("Allocation error", -ENOMEM);
+			goto accept; 
+		}
+
 		memcpy(payload, raw_payload, raw_payload_len);

 		void *iph;
@ -151,7 +165,7 @@ int process_tcp_packet(const uint8_t *raw_payload, uint32_t raw_payload_len) {

 		if (ret < 0) {
 			lgerror("tcp_payload_split in targ_sni", ret);
-			goto accept;
+			goto accept_lc;
 		}

 		if (config.fk_winsize) {
@ -198,14 +212,14 @@ int process_tcp_packet(const uint8_t *raw_payload, uint32_t raw_payload_len) {
 				ret = send_tcp_frags(payload, payload_len, poses, cnt, 0);
 				if (ret < 0) {
 					lgerror("tcp4 send frags", ret);
-					goto accept;
+					goto accept_lc;
 				}

-				goto drop;
+				goto drop_lc;
 			}
 			break;
 			case FRAG_STRAT_IP: 
-			if (ipxv != IP4VERSION) {
+			if (ipxv == IP4VERSION) {
 				ipd_offset = ((char *)data - (char *)tcph) + vrd.sni_offset;
 				mid_offset = ipd_offset + vrd.sni_len / 2;
 				mid_offset += 8 - mid_offset % 8;
@ -232,27 +246,36 @@ int process_tcp_packet(const uint8_t *raw_payload, uint32_t raw_payload_len) {
 				ret = send_ip4_frags(payload, payload_len, poses, cnt, 0);
 				if (ret < 0) {
 					lgerror("ip4 send frags", ret);
-					goto accept;
+					goto accept_lc;
 				}

-				goto drop;
-				break;
+				goto drop_lc;
 			} else {
 				printf("WARNING: IP fragmentation is supported only for IPv4\n");	
+				goto default_send;
 			}
 			default:
+			default_send:
 				ret = instance_config.send_raw_packet(payload, payload_len);
 				if (ret < 0) {
 					lgerror("raw pack send", ret);
-					goto accept;
+					goto accept_lc;
 				}

-				goto drop;
+				goto drop_lc;
 		}



+		goto drop_lc;
+
+accept_lc:
+		NETBUF_FREE(payload);
+		goto accept;
+drop_lc:
+		NETBUF_FREE(payload);
 		goto drop;
+
 	}

 accept:
@ -267,8 +290,8 @@ drop:
 	return PKT_DROP;
 }

-int process_udp4_packet(const uint8_t *pkt, uint32_t pktlen) {
-	const struct iphdr *iph;
+int process_udp_packet(const uint8_t *pkt, uint32_t pktlen) {
+	const void *iph;
 	uint32_t iph_len;
 	const struct udphdr *udph;
 	const uint8_t *data;
@ -277,8 +300,8 @@ int process_udp4_packet(const uint8_t *pkt, uint32_t pktlen) {
 	lgtrace_start("Got udp packet");
 	lgtrace_addp("IPv%d", ipver);

-	int ret = udp4_payload_split((uint8_t *)pkt, pktlen,
-			      (struct iphdr **)&iph, &iph_len, 
+	int ret = udp_payload_split((uint8_t *)pkt, pktlen,
+			      (void **)&iph, &iph_len, 
 			      (struct udphdr **)&udph,
 			      (uint8_t **)&data, &dlen);

@ -358,8 +381,19 @@ int send_ip4_frags(const uint8_t *packet, uint32_t pktlen, const uint32_t *poses
 				packet, pktlen);
 		}
 	} else {
-		uint8_t frag1[MAX_PACKET_SIZE];
-		uint8_t frag2[MAX_PACKET_SIZE];
+		NETBUF_ALLOC(frag1, MAX_PACKET_SIZE);
+		if (!NETBUF_CHECK(frag1)) {
+			lgerror("Allocation error", -ENOMEM);
+			return -ENOMEM;
+		}
+
+		NETBUF_ALLOC(frag2, MAX_PACKET_SIZE);
+		if (!NETBUF_CHECK(frag2)) {
+			lgerror("Allocation error", -ENOMEM);
+			NETBUF_FREE(frag1);
+			return -ENOMEM;
+		}
+
 		uint32_t f1len = MAX_PACKET_SIZE;
 		uint32_t f2len = MAX_PACKET_SIZE;

@ -367,7 +401,8 @@ int send_ip4_frags(const uint8_t *packet, uint32_t pktlen, const uint32_t *poses

 		if (dvs > poses[0]) {
 			lgerror("send_frags: Recursive dvs(%d) is more than poses0(%d)", -EINVAL, dvs, poses[0]);
-			return -EINVAL;
+			ret = -EINVAL;
+			goto erret_lc;
 		}

 		ret = ip4_frag(packet, pktlen, poses[0] - dvs, 
@ -375,7 +410,7 @@ int send_ip4_frags(const uint8_t *packet, uint32_t pktlen, const uint32_t *poses

 		if (ret < 0) {
 			lgerror("send_frags: frag: with context packet with size %d, position: %d, recursive dvs: %d", ret, pktlen, poses[0], dvs);
-			return ret;
+			goto erret_lc;
 		}

 		if (config.frag_sni_reverse)
@ -383,21 +418,30 @@ int send_ip4_frags(const uint8_t *packet, uint32_t pktlen, const uint32_t *poses
 send_frag1:
 		ret = send_ip4_frags(frag1, f1len, NULL, 0, 0);
 		if (ret < 0) {
-			return ret;
+			goto erret_lc;
 		}

 		if (config.frag_sni_reverse)
-			goto out;
+			goto out_lc;

 send_frag2:
 		dvs += poses[0];
 		ret = send_ip4_frags(frag2, f2len, poses + 1, poses_sz - 1, dvs);
 		if (ret < 0) {
-			return ret;
+			goto erret_lc;
 		}

 		if (config.frag_sni_reverse)
 			goto send_frag1;
+
+out_lc:
+		NETBUF_FREE(frag1);
+		NETBUF_FREE(frag2);
+		goto out;
+erret_lc:
+		NETBUF_FREE(frag1);
+		NETBUF_FREE(frag2);
+		return ret;
 	}

 out:
@ -421,9 +465,28 @@ int send_tcp_frags(const uint8_t *packet, uint32_t pktlen, const uint32_t *poses
 				packet, pktlen);
 		}
 	} else {
-		uint8_t frag1[MAX_PACKET_SIZE];
-		uint8_t frag2[MAX_PACKET_SIZE];
-		uint8_t fake_pad[MAX_PACKET_SIZE];
+		NETBUF_ALLOC(frag1, MAX_PACKET_SIZE);
+		if (!NETBUF_CHECK(frag1)) {
+			lgerror("Allocation error", -ENOMEM);
+			return -ENOMEM;
+		}
+
+		NETBUF_ALLOC(frag2, MAX_PACKET_SIZE);
+		if (!NETBUF_CHECK(frag2)) {
+			lgerror("Allocation error", -ENOMEM);
+			NETBUF_FREE(frag1);
+			return -ENOMEM;
+		}
+
+		NETBUF_ALLOC(fake_pad, MAX_PACKET_SIZE);
+		if (!NETBUF_CHECK(fake_pad)) {
+			lgerror("Allocation error", -ENOMEM);
+			NETBUF_FREE(frag1);
+			NETBUF_FREE(frag2);
+			return -ENOMEM;
+		}
+
+
 		uint32_t f1len = MAX_PACKET_SIZE;
 		uint32_t f2len = MAX_PACKET_SIZE;
 		uint32_t fake_pad_len = MAX_PACKET_SIZE;
@ -432,7 +495,8 @@ int send_tcp_frags(const uint8_t *packet, uint32_t pktlen, const uint32_t *poses

 		if (dvs > poses[0]) {
 			lgerror("send_frags: Recursive dvs(%d) is more than poses0(%d)", -EINVAL, dvs, poses[0]);
-			return -EINVAL;
+			ret = -EINVAL;
+			goto erret_lc;
 		}


@ -443,7 +507,7 @@ int send_tcp_frags(const uint8_t *packet, uint32_t pktlen, const uint32_t *poses

 		if (ret < 0) {
 			lgerror("send_frags: tcp_frag: with context packet with size %d, position: %d, recursive dvs: %d", ret, pktlen, poses[0], dvs);
-			return ret;
+			goto erret_lc;
 		}


@ -454,11 +518,11 @@ send_frag1:
 		{
 			ret = send_tcp_frags(frag1, f1len, NULL, 0, 0);
 			if (ret < 0) {
-				return ret;
+				goto erret_lc;
 			}

 			if (config.frag_sni_reverse) 
-				goto out;
+				goto out_lc;
 		}

 send_fake:
@ -468,7 +532,7 @@ send_fake:
 			ret = tcp_payload_split(frag2, f2len, NULL, &iphfl, NULL, &tcphfl, NULL, NULL);
 			if (ret < 0) {
 				lgerror("Invalid frag2", ret);
-				return ret;
+				goto erret_lc;
 			}
 			memcpy(fake_pad, frag2, iphfl + tcphfl);
 			memset(fake_pad + iphfl + tcphfl, 0, f2len - iphfl - tcphfl);
@ -481,11 +545,11 @@ send_fake:
 			ret = fail_packet(fake_pad, &fake_pad_len, MAX_PACKET_SIZE);
 			if (ret < 0) {
 				lgerror("Failed to fail packet", ret);
-				return ret;
+				goto erret_lc;
 			}
 			ret = send_tcp_frags(fake_pad, fake_pad_len, NULL, 0, 0);
 			if (ret < 0) {
-				return ret;
+				goto erret_lc;
 			}

 		}
@ -498,12 +562,22 @@ send_frag2:
 			dvs += poses[0];
 			ret = send_tcp_frags(frag2, f2len, poses + 1, poses_sz - 1, dvs);
 			if (ret < 0) {
-				return ret;
+				goto erret_lc;
 			}

 			if (config.frag_sni_reverse)
 				goto send_fake;
 		}
+out_lc:
+		NETBUF_FREE(frag1);
+		NETBUF_FREE(frag2);
+		NETBUF_FREE(fake_pad);
+		goto out;
+erret_lc:
+		NETBUF_FREE(frag1);
+		NETBUF_FREE(frag2);
+		NETBUF_FREE(fake_pad);
+		return ret;
 	}
 out:
 	return 0;
@ -523,20 +597,25 @@ int post_fake_sni(const void *iph, unsigned int iph_len,
 	struct tcphdr *fstcph = (void *)rfstcph;

 	for (int i = 0; i < sequence_len; i++) {
-		uint8_t fake_sni[MAX_PACKET_SIZE];
+		NETBUF_ALLOC(fake_sni, MAX_PACKET_SIZE);
+		if (!NETBUF_CHECK(fake_sni)) {
+			lgerror("Allocation error", -ENOMEM);
+			return -ENOMEM;
+		}
 		uint32_t fsn_len = MAX_PACKET_SIZE;
 		ret = gen_fake_sni(fsiph, iph_len, fstcph, tcph_len, 
 		     fake_sni, &fsn_len);
 		if (ret < 0) {
 			lgerror("gen_fake_sni", ret);
-			return ret;
+			goto erret_lc;
 		}

 		lgtrace_addp("post fake sni #%d", i + 1);
+		lgtrace_addp("post with %d", fsn_len);
 		ret = instance_config.send_raw_packet(fake_sni, fsn_len);
 		if (ret < 0) {
 			lgerror("send fake sni", ret);
-			return ret;
+			goto erret_lc;
 		}

 		uint32_t iph_len;
@ -555,40 +634,21 @@ int post_fake_sni(const void *iph, unsigned int iph_len,
 		fsiph = (void *)rfsiph;
 		fstcph = (void *)rfstcph;

+		NETBUF_FREE(fake_sni);
+		continue;
+erret_lc:
+		NETBUF_FREE(fake_sni);
+		return ret;
 	}

 	return 0;
 }

-void z_function(const char *str, int *zbuf, size_t len) {
-	zbuf[0] = len;
-
-	ssize_t lh = 0, rh = 1;
-	for (ssize_t i = 1; i < len; i++) {
-		zbuf[i] = 0;
-		if (i < rh) {
-			zbuf[i] = min(zbuf[i - lh], rh - i);
-		}
-
-		while (i + zbuf[i] < len && str[zbuf[i]] == str[i + zbuf[i]])
-			zbuf[i]++;
-
-		if (i + zbuf[i] > rh) {
-			lh = i;
-			rh = i + zbuf[i];
-		}
-	}
-}
-
 #define TLS_CONTENT_TYPE_HANDSHAKE 0x16
 #define TLS_HANDSHAKE_TYPE_CLIENT_HELLO 0x01
 #define TLS_EXTENSION_SNI 0x0000
 #define TLS_EXTENSION_CLIENT_HELLO_ENCRYPTED 0xfe0d

-typedef uint8_t uint8_t;
-typedef uint32_t uint32_t;
-typedef uint16_t uint16_t;
-
 /**
 * Processes tls payload of the tcp request.
 * 
@ -609,9 +669,7 @@ struct tls_verdict analyze_tls_data(

 		uint8_t tls_content_type = *msgData;
 		uint8_t tls_vmajor = *(msgData + 1);
-		uint8_t tls_vminor = *(msgData + 2);
 		uint16_t message_length = ntohs(*(uint16_t *)(msgData + 3));
-		const uint8_t *message_length_ptr = msgData + 3;

 		if (tls_vmajor != 0x03) goto nextMessage;

@ -635,7 +693,6 @@ struct tls_verdict analyze_tls_data(

 		const uint8_t *msgPtr = handshakeProto;
 		msgPtr += 1; 
-		const uint8_t *handshakeProto_length_ptr = msgPtr + 1;
 		msgPtr += 3 + 2 + 32;

 		if (msgPtr + 1 >= data_end) break;
@ -655,7 +712,6 @@ struct tls_verdict analyze_tls_data(

 		if (msgPtr + 2 >= data_end) break;
 		uint16_t extensionsLen = ntohs(*(uint16_t *)msgPtr);
-		const uint8_t *extensionsLen_ptr = msgPtr;
 		msgPtr += 2;

 		const uint8_t *extensionsPtr = msgPtr;
@ -672,7 +728,6 @@ struct tls_verdict analyze_tls_data(

 			uint16_t extensionLen = 
 				ntohs(*(uint16_t *)extensionPtr);
-			const uint8_t *extensionLen_ptr = extensionPtr;
 			extensionPtr += 2;


@ -687,14 +742,13 @@ struct tls_verdict analyze_tls_data(
 			if (sni_ext_ptr + 2 >= extensions_end) break;
 			uint16_t sni_ext_dlen = ntohs(*(uint16_t *)sni_ext_ptr);

-			const uint8_t *sni_ext_dlen_ptr = sni_ext_ptr;
 			sni_ext_ptr += 2;

 			const uint8_t *sni_ext_end = sni_ext_ptr + sni_ext_dlen;
 			if (sni_ext_end >= extensions_end) break;
 			
 			if (sni_ext_ptr + 3 >= sni_ext_end) break;
-			uint8_t sni_type = *sni_ext_ptr++;
+			sni_ext_ptr++;
 			uint16_t sni_len = ntohs(*(uint16_t *)sni_ext_ptr);
 			sni_ext_ptr += 2;

@ -796,12 +850,26 @@ brute:
 			config.domains_str[i] == ','	|| 
 			config.domains_str[i] == '\n'	)) {

-			uint8_t buf[MAX_PACKET_SIZE]; 
-			int zbuf[MAX_PACKET_SIZE]; 
 			unsigned int domain_len = (i - j);
 			const char *domain_startp = config.domains_str + j;

-			if (domain_len + dlen + 1> MAX_PACKET_SIZE) continue;
+			if (domain_len + dlen + 1> MAX_PACKET_SIZE) { 
+				continue;
+			}
+
+			NETBUF_ALLOC(buf, MAX_PACKET_SIZE);
+			if (!NETBUF_CHECK(buf)) {
+				lgerror("Allocation error", -ENOMEM);
+				goto out;
+			}
+			NETBUF_ALLOC(nzbuf, MAX_PACKET_SIZE * sizeof(int));
+			if (!NETBUF_CHECK(nzbuf)) {
+				lgerror("Allocation error", -ENOMEM);
+				NETBUF_FREE(buf);
+				goto out;
+			}
+
+			int *zbuf = (void *)nzbuf;

 			memcpy(buf, domain_startp, domain_len);
 			memcpy(buf + domain_len, "#", 1);
@ -814,12 +882,17 @@ brute:
 					vrd.target_sni = 1;
 					vrd.sni_len = domain_len;
 					vrd.sni_offset = (k - domain_len - 1);
+					NETBUF_FREE(buf);
+					NETBUF_FREE(nzbuf);
 					goto out;
 				}
 			}


 			j = i + 1;
+
+			NETBUF_FREE(buf);
+			NETBUF_FREE(nzbuf);
 		}
 	}

@ -849,7 +922,7 @@ int gen_fake_sni(const void *ipxh, uint32_t iph_len,
 		memcpy(buf, iph, iph_len);
 		struct ip6_hdr *niph = (struct ip6_hdr *)buf;

-		niph->ip6_ctlun.ip6_un1.ip6_un1_nxt = IPPROTO_TCP;
+		niph->ip6_nxt = IPPROTO_TCP;
 	} else {
 		return -EINVAL;
 	}
@ -865,14 +938,13 @@ int gen_fake_sni(const void *ipxh, uint32_t iph_len,
 	memcpy(buf + iph_len, tcph, tcph_len);
 	memcpy(buf + iph_len + tcph_len, data, data_len);

-	struct tcphdr *ntcph = (struct tcphdr *)(buf + iph_len);

 	if (ipxv == IP4VERSION) {
 		struct iphdr *niph = (struct iphdr *)buf;
 		niph->tot_len = htons(dlen);
 	} else if (ipxv == IP6VERSION) {
 		struct ip6_hdr *niph = (struct ip6_hdr *)buf;
-		niph->ip6_ctlun.ip6_un1.ip6_un1_plen = htons(dlen - iph_len);
+		niph->ip6_plen = htons(dlen - iph_len);
 	}

 	fail_packet(buf, &dlen, *buflen);
@ -911,8 +983,6 @@ int fail_packet(uint8_t *payload, uint32_t *plen, uint32_t avail_buflen) {
 		return ret;
 	}

-	int sizedelta = 0;
-

 	if (config.faking_strategy == FAKE_STRAT_RAND_SEQ) {
 		lgtrace("fake seq: %u -> ", ntohl(tcph->seq));
@ -920,7 +990,7 @@ int fail_packet(uint8_t *payload, uint32_t *plen, uint32_t avail_buflen) {
 		if (config.fakeseq_offset) {
 			tcph->seq = htonl(ntohl(tcph->seq) - config.fakeseq_offset);
 		} else {
-#ifdef KERNEL_SCOPE
+#ifdef KERNEL_SPACE
 			tcph->seq = 124;
 #else
 			tcph->seq = random();
@ -940,7 +1010,7 @@ int fail_packet(uint8_t *payload, uint32_t *plen, uint32_t avail_buflen) {
 		if (ipxv == IP4VERSION) {
 			((struct iphdr *)iph)->ttl = config.faking_ttl;
 		} else if (ipxv == IP6VERSION) {
-			((struct ip6_hdr *)iph)->ip6_ctlun.ip6_un1.ip6_un1_hlim = config.faking_ttl;
+			((struct ip6_hdr *)iph)->ip6_hops = config.faking_ttl;
 		} else {
 			lgerror("fail_packet: IP version is unsupported", -EINVAL);
 			return -EINVAL;
@ -955,7 +1025,12 @@ int fail_packet(uint8_t *payload, uint32_t *plen, uint32_t avail_buflen) {
 				return -1;
 			}
 			uint8_t *ndata = data + delta;
-			memcpy(ndata, data, dlen);
+			uint8_t *ndptr = ndata + dlen;
+			uint8_t *dptr = data + dlen;
+			for (size_t i = dlen + 1; i > 0; i--) {
+				*ndptr = *dptr;
+				--ndptr, --dptr;
+			}
 			data = ndata;
 			tcph_len = tcph_len + delta;
 			tcph->doff = tcph_len >> 2;
--- a/mangle.h
+++ b/mangle.h
@ -53,7 +53,7 @@ int process_tcp_packet(const uint8_t *raw_payload, uint32_t raw_payload_len);
 * Processes the UDP packet.
 * Returns verdict.
 */
-int process_udp4_packet(const uint8_t *pkt, uint32_t pktlen);
+int process_udp_packet(const uint8_t *pkt, uint32_t pktlen);

 /**
 * Sends fake client hello.
--- a/nf_wrapper.h
+++ b/nf_wrapper.h
@ -0,0 +1,84 @@
+/**
+ * Thanks https://github.com/NICMx/Jool/blob/5f60dcda5944b01cc43c3be342aad26af8161bcb/include/nat64/mod/common/nf_wrapper.h for mapped kernel versions
+ */
+#ifndef _JOOL_MOD_NF_WRAPPER_H
+#define _JOOL_MOD_NF_WRAPPER_H
+
+/**
+ * @file
+ * The kernel API is far from static. In particular, the Netfilter packet entry
+ * function keeps changing. nf_hook.c, the file where we declare our packet
+ * entry function, has been quite difficult to read for a while now. It's pretty
+ * amusing, because we don't even use any of the noisy arguments.
+ *
+ * This file declares a usable function header that abstracts away all those
+ * useless arguments.
+ */
+
+#include <linux/version.h>
+
+/* If this is a Red Hat-based kernel (Red Hat, CentOS, Fedora, etc)... */
+#ifdef RHEL_RELEASE_CODE
+
+#if RHEL_RELEASE_CODE >= RHEL_RELEASE_VERSION(7, 2)
+#define NF_CALLBACK(name, skb) unsigned int name( \
+		const struct nf_hook_ops *ops, \
+		struct sk_buff *skb, \
+		const struct net_device *in, \
+		const struct net_device *out, \
+		const struct nf_hook_state *state) \
+
+#elif RHEL_RELEASE_CODE >= RHEL_RELEASE_VERSION(7, 0)
+#define NF_CALLBACK(name, skb) unsigned int name( \
+		const struct nf_hook_ops *ops, \
+		struct sk_buff *skb, \
+		const struct net_device *in, \
+		const struct net_device *out, \
+		int (*okfn)(struct sk_buff *))
+
+#else
+
+#error "Sorry; this version of RHEL is not supported because it's kind of old."
+
+#endif /* RHEL_RELEASE_CODE >= x */
+
+
+/* If this NOT a RedHat-based kernel (Ubuntu, Debian, SuSE, etc)... */
+#else
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 4, 0)
+#define NF_CALLBACK(name, skb) unsigned int name( \
+		void *priv, \
+		struct sk_buff *skb, \
+		const struct nf_hook_state *state)
+
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 1, 0)
+#define NF_CALLBACK(name, skb) unsigned int name( \
+		const struct nf_hook_ops *ops, \
+		struct sk_buff *skb, \
+		const struct nf_hook_state *state)
+
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(3, 13, 0)
+#define NF_CALLBACK(name, skb) unsigned int name( \
+		const struct nf_hook_ops *ops, \
+		struct sk_buff *skb, \
+		const struct net_device *in, \
+		const struct net_device *out, \
+		int (*okfn)(struct sk_buff *))
+
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(3, 0, 0)
+#define NF_CALLBACK(name, skb) unsigned int name( \
+		unsigned int hooknum, \
+		struct sk_buff *skb, \
+		const struct net_device *in, \
+		const struct net_device *out, \
+		int (*okfn)(struct sk_buff *))
+
+#else
+#error "Linux < 3.0 isn't supported at all."
+
+#endif /* LINUX_VERSION_CODE > n */
+
+#endif /* RHEL or not RHEL */
+
+#endif /* _JOOL_MOD_NF_WRAPPER_H */
--- a/quic.c
+++ b/quic.c
@ -48,7 +48,7 @@ int quic_parse_data(uint8_t *raw_payload, uint32_t raw_payload_len,
 	}

 	uint8_t found = 0;
-	for (uint8_t i = 0; i < sizeof(supported_versions); i++) {
+	for (uint8_t i = 0; i < 2; i++) {
 		if (ntohl(nqch->version) == supported_versions[i]) {
 			found = 1;
 		}
--- a/types.h
+++ b/types.h
@ -3,26 +3,18 @@
 #define TYPES_H
 #include <asm/byteorder.h>

-#ifdef KERNEL_SCOPE
+#ifdef KERNEL_SPACE
 #include <linux/errno.h> // IWYU pragma: export
 #include <linux/string.h> // IWYU pragma: export

 #include <linux/types.h>
-typedef __u8	uint8_t;
-typedef __u16	uint16_t;
-typedef __u32 	uint32_t;
-typedef __u64 	uint64_t;
-typedef __i8	int8_t;
-typedef __i16	int16_t;
-typedef __i32	int32_t;
-typedef __i64	int64_t;
-#else /* USERSPACE_SCOPE */
+#else /* USER_SPACE */

 #include <errno.h>  // IWYU pragma: export
 #include <stdint.h> // IWYU pragma: export
 #include <string.h> // IWYU pragma: export

-#endif /* SCOPES */
+#endif /* SPACES */

 // Network specific structures
 #ifdef KERNEL_SPACE
@ -30,15 +22,36 @@ typedef __i64	int64_t;
 #include <linux/net.h> // IWYU pragma: export
 #include <linux/in.h> // IWYU pragma: export
 #include <linux/ip.h> // IWYU pragma: export
+#include <linux/ipv6.h> // IWYU pragma: export
 #include <linux/tcp.h> // IWYU pragma: export
+#include <linux/version.h>
+
+#define ip6_hdr ipv6hdr

 /* from <netinet/ip.h> */
 #define	IP_RF 0x8000			/* reserved fragment flag */
 #define	IP_DF 0x4000			/* dont fragment flag */
 #define	IP_MF 0x2000			/* more fragments flag */
 #define	IP_OFFMASK 0x1fff		/* mask for fragmenting bits */
+
+#ifdef __LITTLE_ENDIAN
+#define __BIG_ENDIAN 4321
+#define __BYTE_ORDER __LITTLE_ENDIAN
+#elif defined(__BIG_ENDIAN)
+#define __LITTLE_ENDIAN 1234
+#define __BYTE_ORDER __BIG_ENDIAN
 #else
-#define USER_SPACE
+#error "Unsupported endian"
+#endif
+
+#define ip6_plen payload_len
+#define ip6_nxt nexthdr
+#define ip6_hops hop_limit
+#define ip6_hlim hop_limit
+#define ip6_src saddr
+#define ip6_dst daddr
+
+#else /* USER_SPACE */
 #include <arpa/inet.h>		// IWYU pragma: export
 #include <netinet/ip.h>		// IWYU pragma: export
 #include <netinet/ip6.h>	// IWYU pragma: export
@ -46,6 +59,8 @@ typedef __i64	int64_t;
 #include <netinet/udp.h>	// IWYU pragma: export
 #endif

+#ifndef KERNEL_SPACE
+
 #define max(a,b)__extension__\
 ({                           \
    __typeof__ (a) _a = (a); \
@ -60,4 +75,28 @@ typedef __i64	int64_t;
    _a < _b ? _a : _b;       \
 })

+#endif /* not a KERNEL_SPACE */
+
+/**
+ * Use NETBUF_ALLOC and NETBUF_FREE as an abstraction of memory allocation.
+ * Do not use it within expressions, consider these defines as separate statements.
+ *
+ * Use NETBUF_CHECK to check that buffer was properly allocated.
+ */
+#ifdef KERNEL_SPACE
+#include <linux/gfp.h>
+#define NETBUF_ALLOC(buf, buf_len) __u8* buf = kmalloc(buf_len, GFP_KERNEL);
+#define NETBUF_CHECK(buf) ((buf) != NULL)
+#define NETBUF_FREE(buf) kfree(buf);
+#elif defined(ALLOC_MALLOC)
+#include <stdlib.h>
+#define NETBUF_ALLOC(buf, buf_len) __u8* buf = malloc(buf_len);
+#define NETBUF_CHECK(buf) ((buf) != NULL)
+#define NETBUF_FREE(buf) free(buf);
+#else
+#define NETBUF_ALLOC(buf, buf_len) __u8 buf[buf_len];
+#define NETBUF_CHECK(buf) (1)
+#define NETBUF_FREE(buf) ;
+#endif
+
 #endif /* TYPES_H */
--- a/utils.c
+++ b/utils.c
@ -1,14 +1,19 @@
 #include "utils.h"
 #include "logging.h"
-#include <netinet/in.h>
+#include "types.h"

-#ifdef KERNEL_SPACE
-#include <linux/ip.h>
-#else 
+#ifndef KERNEL_SPACE 
 #include <stdlib.h>
 #include <libnetfilter_queue/libnetfilter_queue_ipv4.h>
 #include <libnetfilter_queue/libnetfilter_queue_ipv6.h>
 #include <libnetfilter_queue/libnetfilter_queue_tcp.h>
+#else
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 24))
+	#include <net/ip6_checksum.h>
+	#include <net/checksum.h>
+#else
+	#include <net/checksum.h>
+#endif
 #endif


@ -37,9 +42,14 @@ void ip4_set_checksum(struct iphdr *iph)
 }

 void tcp6_set_checksum(struct tcphdr *tcph, struct ip6_hdr *iph) {
-	uint16_t old_check = ntohs(tcph->check);
-
+#ifdef KERNEL_SPACE
+	tcph->check = 0;
+	tcph->check = csum_ipv6_magic(&iph->saddr, &iph->daddr, 
+		 ntohs(iph->ip6_plen), IPPROTO_TCP, 
+		 csum_partial(tcph, ntohs(iph->ip6_plen), 0));
+#else
 	nfq_tcp_compute_checksum_ipv6(tcph, iph);
+#endif
 }

 int set_ip_checksum(void *iph, uint32_t iphb_len) {
@ -157,7 +167,7 @@ int ip6_payload_split(uint8_t *pkt, uint32_t buflen,
 	}

 	uint32_t hdr_len = sizeof(struct ip6_hdr);
-	uint32_t pktlen = ntohs(hdr->ip6_ctlun.ip6_un1.ip6_un1_plen);
+	uint32_t pktlen = ntohs(hdr->ip6_plen);
 	if (buflen < pktlen) {
 		lgerror("ip6_payload_split: buflen cmp pktlen: %d %d", -EINVAL, buflen, pktlen);
 		return -EINVAL;
@ -194,7 +204,7 @@ int tcp6_payload_split(uint8_t *pkt, uint32_t buflen,


 	if (
-		hdr->ip6_ctlun.ip6_un1.ip6_un1_nxt != IPPROTO_TCP || 
+		hdr->ip6_nxt != IPPROTO_TCP || 
 		tcph_plen < sizeof(struct tcphdr)) {
 		return -EINVAL;
 	}
@ -240,7 +250,6 @@ int udp4_payload_split(uint8_t *pkt, uint32_t buflen,
 	struct iphdr *hdr;
 	uint32_t hdr_len;
 	struct udphdr *uhdr;
-	uint32_t uhdr_len;
 	
 	uint8_t *ip_ph;
 	uint32_t ip_phlen;
@ -272,6 +281,59 @@ int udp4_payload_split(uint8_t *pkt, uint32_t buflen,
 	return 0;
 }

+int udp6_payload_split(uint8_t *pkt, uint32_t buflen,
+		       struct ip6_hdr **iph, uint32_t *iph_len,
+		       struct udphdr **udph,
+		       uint8_t **payload, uint32_t *plen) {
+	struct ip6_hdr *hdr;
+	uint32_t hdr_len;
+	struct udphdr *uhdr;
+	
+	uint8_t *ip_ph;
+	uint32_t ip_phlen;
+
+	if (ip6_payload_split(pkt, buflen, &hdr, &hdr_len, 
+			&ip_ph, &ip_phlen)){
+		return -EINVAL;
+	}
+
+
+	if (
+		hdr->ip6_nxt != IPPROTO_UDP || 
+		ip_phlen < sizeof(struct udphdr)) {
+		return -EINVAL;
+	}
+
+
+	uhdr = (struct udphdr *)(ip_ph);
+	if (uhdr->len != 0 && ntohs(uhdr->len) != ip_phlen) {
+		return -EINVAL;
+	}
+
+	if (iph) *iph = hdr;
+	if (iph_len) *iph_len = hdr_len;
+	if (udph) *udph = uhdr;
+	if (payload) *payload = ip_ph + sizeof(struct udphdr);
+	if (plen) *plen = ip_phlen - sizeof(struct udphdr);
+
+	return 0;
+}
+
+int udp_payload_split(uint8_t *pkt, uint32_t buflen,
+		      void **iph, uint32_t *iph_len,
+		      struct udphdr **udph,
+		      uint8_t **payload, uint32_t *plen) {
+	int netvers = netproto_version(pkt, buflen);
+	if (netvers == IP4VERSION) {
+		return udp4_payload_split(pkt, buflen, (struct iphdr **)iph, iph_len, udph, payload, plen);
+	} else if (netvers == IP6VERSION) {
+		return udp6_payload_split(pkt, buflen, (struct ip6_hdr **)iph, iph_len, udph, payload, plen);
+	} else {
+		lgerror("Internet Protocol version is unsupported", -EINVAL);
+		return -EINVAL;
+	}
+}
+
 // split packet to two ipv4 fragments.
 int ip4_frag(const uint8_t *pkt, uint32_t buflen, uint32_t payload_offset, 
 			uint8_t *frag1, uint32_t *f1len, 
@ -426,8 +488,8 @@ int tcp_frag(const uint8_t *pkt, uint32_t buflen, uint32_t payload_offset,
 	} else {
 		struct ip6_hdr *s1_hdr = (void *)seg1;
 		struct ip6_hdr *s2_hdr = (void *)seg2;
-		s1_hdr->ip6_ctlun.ip6_un1.ip6_un1_plen = htons(s1_dlen - hdr_len);
-		s2_hdr->ip6_ctlun.ip6_un1.ip6_un1_plen = htons(s2_dlen - hdr_len);
+		s1_hdr->ip6_plen = htons(s1_dlen - hdr_len);
+		s2_hdr->ip6_plen = htons(s2_dlen - hdr_len);
 	}

 	struct tcphdr *s1_tcph = (void *)(seg1 + hdr_len);
@ -440,3 +502,24 @@ int tcp_frag(const uint8_t *pkt, uint32_t buflen, uint32_t payload_offset,

 	return 0;
 }
+
+void z_function(const char *str, int *zbuf, size_t len) {
+	zbuf[0] = len;
+
+	int lh = 0, rh = 1;
+	for (int i = 1; i < (int)len; i++) {
+		zbuf[i] = 0;
+		if (i < rh) {
+			zbuf[i] = min(zbuf[i - lh], rh - i);
+		}
+
+		while (i + zbuf[i] < len && str[zbuf[i]] == str[i + zbuf[i]])
+			zbuf[i]++;
+
+		if (i + zbuf[i] > rh) {
+			lh = i;
+			rh = i + zbuf[i];
+		}
+	}
+}
+
--- a/utils.h
+++ b/utils.h
@ -81,6 +81,16 @@ int udp4_payload_split(uint8_t *pkt, uint32_t buflen,
 		       struct udphdr **udph,
 		       uint8_t **payload, uint32_t *plen);

+int udp6_payload_split(uint8_t *pkt, uint32_t buflen,
+		       struct ip6_hdr **iph, uint32_t *iph_len,
+		       struct udphdr **udph,
+		       uint8_t **payload, uint32_t *plen);
+
+int udp_payload_split(uint8_t *pkt, uint32_t buflen,
+		      void **iph, uint32_t *iph_len,
+		      struct udphdr **udph,
+		      uint8_t **payload, uint32_t *plen);
+
 void tcp4_set_checksum(struct tcphdr *tcph, struct iphdr *iph);
 void ip4_set_checksum(struct iphdr *iph);
 void ip6_set_checksum(struct ip6_hdr *iph);
@ -89,4 +99,6 @@ void tcp6_set_checksum(struct tcphdr *tcph, struct ip6_hdr *iph);
 int  set_ip_checksum(void *iph, uint32_t iphb_len);
 int  set_tcp_checksum(struct tcphdr *tcph, void *iph, uint32_t iphb_len);

+void z_function(const char *str, int *zbuf, size_t len);
+
 #endif /* UTILS_H */
--- a/youtubeUnblock.c
+++ b/youtubeUnblock.c
@ -234,9 +234,6 @@ static int send_raw_ipv6(const uint8_t *pkt, uint32_t pktlen) {
 		.sin6_addr = iph->ip6_dst
 	};

-	tcp6_set_checksum((void *)(uint8_t *)pkt + sizeof(struct ip6_hdr), (void *)pkt);
-
-
 	if (config.threads != 1)
 		pthread_mutex_lock(&rawsocket_lock);