Merge branch 'main' into 6-openwrt-compilation-issue

README.md

@@ -26,10 +26,17 @@ Here iptables serves every tcp packet, destinating port 443 for this userspace p
 
 Run an application with `youtubeUnblock 537` where `537` stands for the queue-num (must be the same as in the iptables rule).
 
-Systemd daemon is also available. Do `systemctl enable --now youtubeUnblock.service` after installation (uses queue-num `537`). Please, note that systemd will configure iptables manually. If you have troubles with it, delete ExecStartPre and ExecStop from youtubeUnblock.service and configure iptables manually (may be a useful case for nftables).
+Systemd daemon is also available. Do `systemctl enable --now youtubeUnblock.service` after installation (uses queue-num `537`). Please, note that systemd will configure iptables automatically. If you have troubles with it, delete ExecStartPre and ExecStop from youtubeUnblock.service and configure iptables manually (may be a useful case for nftables).
 
 Also DNS over HTTPS (DOH) is preferred for additional anonimity. 
 
+## Troubleshooting
+If you have any troubles with youtubeUnblock, here are some options to tune. If them don't work in your case, please, open an issue. You can pass these options in make CFLAGS (`make CFLAGS=...`) or edit CFLAGS variable in Makefile.
+Available flags:
+- -DUSE_SEG2_DELAY This flag forces youtubeUnblock to wait little bit before send the 2nd part of the split packet. You can tune the amount of time in `#define SEG2_DELAY 100` where 100 stands for milliseconds.
+- -DNO_FAKE_SNI This flag disables -DFAKE_SNI which forces youtubeUnblock to send at least three packets instead of one with TLS ClientHello: Fake ClientHello, 1st part of original ClientHello, 2nd part of original ClientHello. Use this flag if you got gen_fake_sni error. Track this issue in https://github.com/Waujito/youtubeUnblock/issues/17
+- -DNOUSE_GSO This flag disables fix for Google Chrome fat ClientHello. The GSO is well tested now, so this flag probably won't fix anything.
+
 ## OpenWRT case
 The package is also compatible with routers. The router should be running by free opensource linux-based system such as [OpenWRT](https://openwrt.org/). You should cross-compile it under your host machine. Be ready for compilation errors and a lot of googling about it. It is not such a trivial process! You can get crosscompilation toolsuite compatible with your router from OpenWRT repositories. For example, I have ramips/mt76x8 based router so for me the toolsuite is on https://downloads.openwrt.org/releases/23.05.3/targets/ramips/mt76x8/ and called `openwrt-toolchain-23.05.3-ramips-mt76x8_gcc-12.3.0_musl.Linux-x86_64.tar.xz`. You can find out more about your router model on it's openwrt page. When you download the toolsuite, untar it somewhere. Now we are ready for compilation. My cross gcc asked me to create a staging dir for it and pass it as an environment variable. Also you should notice toolsuite packages and replace my make command with yours. ```STAGING_DIR=temp make CC=/usr/bin/mipsel-openwrt-linux-gcc LD=/usr/bin/mipsel-openwrt-linux-ld AR=/usr/bin/mipsel-openwrt-linux-ar OBJDUMP=/usr/bin/mipsel-openwrt-linux-objdump NM=/usr/bin/mipsel-openwrt-linux-nm STRIP=/usr/bin/mipsel-openwrt-linux-strip CROSS_COMPILE_PLATFORM=mipsel-buildroot-linux-gnu```. Take a look at `CROSS_COMPILE_PLATFORM` It is required by autotools but I think it is not necessary. Anyways I put `mipsel-buildroot-linux-gnu` in here. For your model may be an [automake cross-compile manual](https://www.gnu.org/software/automake/manual/html_node/Cross_002dCompilation.html) will be helpful. When compilation is done, the binary file will be in build directory. Copy it to your router. Note that an 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`-ed and run.
 
@@ -37,8 +44,4 @@ Now let's talk about a router configuration. I installed a normal iptables user-
 
 Next step is to daemonize the application in openwrt. Copy youtubeUnblock.owrt to /etc/init.d/youtubeUnblock and put the program into /usr/bin/. (Don't forget to `chmod +x` both). Now run `/etc/init.d/youtubeUnblock start`. You can alo run `/etc/init.d/youtubeUnblock enable` to force OpenWRT autostart the program on boot. 
 
-
-## Further development
-Please note that the application needs in further development. Some googlevideo servers may still be unabailable, some may drop out hello packets on Firefox while some may do so on Chrome. If you got in trouble try to disable GSO (Pass -DNOUSE_GSO as CC_FLAGS). Also you may set the program to use IP fragmentation instead of TCP (-DUSE_IP_FRAGMENTATION).
-
 **If you have any questions/suggestions/problems feel free to open an issue.**

raw_replacements.h

@@ -0,0 +1,6 @@
+#ifndef RAW_REPLACEMENTS_H
+#define RAW_REPLACEMENTS_H
+
+const char fake_sni[] = "\276(\001\273\366\234|\335\213\222\023\330\200\030\001\366\350e\000\000\001\001\b\n}\355\267Hm/\217\347\026\003\001\004\316\001\000\004\312\003\003K+\272\314\340\306\374>dw%\f\223\346\225\270\270~\335\027\f\264\341H\267\357\303\216T\322[\371 \245\320\212V6\374\3706\232\0216B\325\273P\b\300>\0332>\362\323\033\322\301\204\022f8\223\214\000\"\023\001\023\003\023\002\300+\300/\314\251\314\250\300,\3000\300\n\300\t\300\023\300\024\000\234\000\235\000/\0005\001\000\004_\000\000\000\023\000\021\000\000\016www.google.com\000\027\000\000\377\001\000\001\000\000\n\000\016\000\f\000\035\000\027\000\030\000\031\001\000\001\001\000\v\000\002\001\000\000\020\000\v\000\t\bhttp/1.1\000\005\000\005\001\000\000\000\000\000\"\000\n\000\b\004\003\005\003\006\003\002\003\0003\000k\000i\000\035\000 \333C\212\234-\t\237#\202\\\231\311\022]\333\341t(\t\276U\373u\234\316J~,^|*Z\000\027\000A\004k\n\255\254\376X\226t\001;n~\033\034.\245\027\024\3762_\352$\374\346^f\fF,\201\275\263\336O\231\001\032\200\357dI\266y\031\323\311vR\232\004\r\366FT\004\335\326\356\256\230B\t\313\000*\000\000\000+\000\005\004\003\004\003\003\000\r\000\030\000\026\004\003\005\003\006\003\b\004\b\005\b\006\004\001\005\001\006\001\002\003\002\001\000-\000\002\001\001\000\034\000\002@\001\376\r\0029\000\000\001\000\003\344\000 \337\306\243\332Y\033\a\252\352\025\365Z\035\223\226\304\255\363\215G\356g\344%}7\217\033n\211^\201\002\017g\267\334\326OD}\336\341ZC\230\226'\225\313\357\211\\\242\273\030k\216\377U\315\206\2410\200\203\332Z\223\005\370\b\304\370f\017\200\023\241\223~?\270{\037b\312\001\270\227\366\356\352\002\314\351\006\237\241q\226\300\314\321o\247{\201\317\230}B\005T\3660\335\320\332r?S\217\tq\036\031\326I|\237]\311 c\f\024r\031\310W\373\257\314q)q\030\237\261\227\217Kd?\257'G\320\020\340\256ND\247\005\341\324\024OP>\370\350\270b\311wAj\t\311\213\365i\203\230x\207\354\245<\274\202\230c\v0Y\263\364\022\303a\200\022\031\314\271rl=\327\336\001\327\264\267\342\353\352=\354[u\224\260\257\034\004\232\023\226}\227\030e\221\"\350\207\027dId\324\305\362N:\035\307`\204\337\201;\221\320\266b\362hrH\345e\206\246%\006\020a4\3430\036\225\215\274\275\360Q&\271\237)\222uK\362\017o\220\226W\357\267#\357\v\023\354\213\2629\331\ad\005/~6k\000[\247\301\270\310qJ\004\303|m5\363\376Y\002\243}6\251x\024\331)GH\335\205rI\032\f\210\a\212\347]\271\030\347.\021\213\365\026\030\340/Ny\r\332\3577\3203\026iX}>\2507\327&XRXU!\017\270I\313\352\350^?\352Uss\017\266pF\222NI\245\307_\305#\361\352\243+-\266\317Q\036s\243\277\355{S&\023>\275\360\215\032V\237XOY\345u>\002\305\252T\354\035\327v{P\352M\233\366\221\270\377\251\261f+rF\201wL2W\266X\252\242X\2536I\337c\205uZ\254Fe\305h\t\371\376\216r\336Y\327h\347*\331\257-ZQ{(\336\226\206\017\037\036\021\341\027z\033\254\235\252\227\224\004?p\243\351\\\263\352\205\327#W\345\255\256\375\267bP\3047\363!*K\003t\212(\306\214P\215\3506j\025\375\213e\254s\000)\001\034\000\367\000\361\002\276W%\232?\326\223\277\211v\017\a\361\347\312N\226\024L\260v\210\271j\324[|\270\344\3773\321-\313b>~\310\253XIR\324)&;\033{g;)\344\255\226\370\347I\\y\020\324\360\211vC\310\226s\267|\273$\341\332\2045qh\245w\2255\214\316\030\255\301\326C\343\304=\245\231h`yd\000#s\002\370\374Z\0336\245\361\226\222\306\032k\2457\016h\314(R;\326T~EHH\352\307\023^\247\363\321`V\340\253Z\233\357\227I\373\337z\177\nv\261\252\371\017\226\223\345\005\315y4\b\236N0\2630\017\215c\305&L\260\346J\237\203Q(\335W\027|>\3553\275j\307?W5\3463kc\350\262C\361 \037w!\371}\214\"I\377|\331@a;\342\3566\312\272Z\327u7\204'\215YBLL\235\236\242\345\215\245T\211a\312\263\342\000! \221\202X$\302\317\203\246\207c{\231\330\264\324\\k\271\272\336\356\002|\261O\207\030+\367P\317\356";
+
+#endif /*RAW_REPLACEMENTS_H*/

youtubeUnblock.c

@@ -19,6 +19,9 @@
 #include <linux/netfilter.h>
 #include <linux/if_ether.h>
 #include <sys/socket.h>
+#include <pthread.h>
+
+#include "raw_replacements.h"
 
 #ifndef NOUSE_GSO
 #define USE_GSO
@@ -30,6 +33,15 @@
 
 #define RAWSOCKET_MARK 0xfc70
 
+#ifdef USE_SEG2_DELAY
+#define SEG2_DELAY 100
+#endif
+
+#ifndef NO_FAKE_SNI
+#define FAKE_SNI
+#endif
+
+
 static struct {
 	uint32_t queue_num;
 	struct mnl_socket *nl;
@@ -564,7 +576,67 @@ nextMessage:
 	return vrd;
 }
 
+static struct pkt_buff *gen_fake_sni(const struct iphdr *iph, const struct tcphdr *tcph) {
+	int ip_len = iph->ihl * 4;
+	int tcp_len = tcph->doff * 4;
 
+	size_t pkt_size = ip_len + sizeof(fake_sni);
+	struct pkt_buff *pkt = pktb_alloc(AF_INET, NULL, 0, pkt_size);
+	if (pkt == NULL) return NULL;
+
+	pktb_mangle(pkt, 0, 0, 0, (const char *)iph, ip_len);
+	pktb_mangle(pkt, ip_len, 0, 0, fake_sni, sizeof(fake_sni));
+
+	int ret = 0;
+	struct iphdr *niph = nfq_ip_get_hdr(pkt);
+	if (!niph) {
+		perror("gen_fake_sni: ip header is null");
+		goto err;
+	}
+
+	niph->protocol = IPPROTO_TCP;
+	niph->tot_len = htons(pkt_size);
+
+	ret = nfq_ip_set_transport_header(pkt, niph);
+	if (ret < 0) {
+		perror("gen_fake_sni: set transport header");
+		goto err;
+	}
+
+	struct tcphdr *ntcph = nfq_tcp_get_hdr(pkt);
+	if (!ntcph) { 
+		perror("gen_fake_sni: nfq_tcp_get_hdr");
+		goto err;
+	}
+
+	ntcph->th_dport = tcph->th_dport;
+	ntcph->th_sport = tcph->th_sport;
+	nfq_ip_set_checksum(niph);
+	nfq_tcp_compute_checksum_ipv4(ntcph, niph);
+
+	return pkt;
+err:
+	pktb_free(pkt);
+	return NULL;
+
+}
+struct dps_t {
+	struct pkt_buff *pkt;
+	// Time for the packet in milliseconds
+	uint32_t timer;
+};
+// Note that the thread will automatically release dps_t and pkt_buff
+void *delay_packet_send(void *data) {
+	struct dps_t *dpdt = data;
+	struct pkt_buff *pkt = dpdt->pkt;
+
+	usleep(dpdt->timer * 1000);
+	send_raw_socket(pkt);
+
+	pktb_free(pkt);
+	free(dpdt);
+	return NULL;
+}
 		     
 static int process_packet(const struct packet_data packet) {
 	char buf[MNL_SOCKET_BUFFER_SIZE];
@@ -629,6 +701,19 @@ static int process_packet(const struct packet_data packet) {
 
 
 #ifdef USE_TCP_SEGMENTATION
+		int ret = 0;
+#ifdef FAKE_SNI
+		struct pkt_buff *fake_sni = gen_fake_sni(ip_header, tcph);
+		if (fake_sni == NULL) goto fallback;
+
+		ret = send_raw_socket(fake_sni);
+		if (ret < 0) {
+			perror("send fake sni\n");
+			pktb_free(fake_sni);
+			goto fallback;
+		}
+#endif
+
 		size_t ipd_offset = vrd.sni_offset;
 		size_t mid_offset = ipd_offset + vrd.sni_len / 2;
 
@@ -638,19 +723,55 @@ static int process_packet(const struct packet_data packet) {
 			packet.payload_len,
 			0);
 
-		if (tcp4_frag(pktb, mid_offset, &frag1, &frag2) < 0) {
-			perror("tcp4_frag");
-			pktb_free(pktb);
+		if (pktb == NULL) {
+			perror("pktb_alloc of payload");
+#ifdef FAKE_SNI
+			pktb_free(fake_sni);
+#endif
 			goto fallback;
 		}
 		
-		if ((send_raw_socket(frag2) == -1) || (send_raw_socket(frag1) == -1)) {
-			perror("raw frags send");
+		if (tcp4_frag(pktb, mid_offset, &frag1, &frag2) < 0) {
+			perror("tcp4_frag");
+			pktb_free(pktb);
+#ifdef FAKE_SNI
+			pktb_free(fake_sni);
+#endif
+
+			goto fallback;
 		}
 
+		ret = send_raw_socket(frag2);
+		if (ret < 0) {
+			errno = ret;
+			perror("raw frags send: frag2");
 			pktb_free(frag1);
+			goto err;
+		}
+		
+#ifdef SEG2_DELAY
+		struct dps_t *dpdt = malloc(sizeof(struct dps_t));
+		dpdt->pkt = frag1;
+		dpdt->timer = SEG2_DELAY;
+		pthread_t thr;
+		pthread_create(&thr, NULL, delay_packet_send, dpdt); 
+		pthread_detach(thr);
+#else
+		ret = send_raw_socket(frag1);
+		if (ret < 0) {
+			errno = ret;
+			perror("raw frags send: frag1");
+			pktb_free(frag1);
+			goto err;
+		}
+		pktb_free(frag1);
+#endif
+err:
 		pktb_free(frag2);
 		pktb_free(pktb);
+#ifdef FAKE_SNI
+		pktb_free(fake_sni);
+#endif
 
 #else
 		// TODO: Implement compute of tcp checksum
@@ -754,9 +875,17 @@ int main(int argc, const char *argv[])
 	}
 
 #ifdef USE_TCP_SEGMENTATION
-	printf("Using TCP segmentation!\n");
+	printf("Using TCP segmentation\n");
 #else 
-	printf("Using IP fragmentation!\n");
+	printf("Using IP fragmentation\n");
+#endif 
+
+#ifdef SEG2_DELAY
+	printf("Some outgoing googlevideo request segments will be delayed for %d ms as of SEG2_DELAY define\n", SEG2_DELAY);
+#endif 
+
+#ifdef FAKE_SNI
+	printf("Fake SNI will be sent before each googlevideo request\n");
 #endif 
 
 	if (open_socket()) {
@@ -792,7 +921,7 @@ int main(int argc, const char *argv[])
 	nfq_nlmsg_cfg_put_params(nlh, NFQNL_COPY_PACKET, 0xffff);
 
 #ifdef USE_GSO
-	printf("GSO is enabled!\n");
+	printf("GSO is enabled\n");
 
         mnl_attr_put_u32(nlh, NFQA_CFG_FLAGS, htonl(NFQA_CFG_F_GSO));
         mnl_attr_put_u32(nlh, NFQA_CFG_MASK, htonl(NFQA_CFG_F_GSO));