Merge pull request #207 from Waujito/udp_update

Add none strategy to udp-faking-strategy

Makefile

@@ -2,7 +2,7 @@ USPACE_TARGETS := default all install uninstall dev run_dev
 KMAKE_TARGETS := kmake kload kunload kreload xmod xtclean
 
 PKG_VERSION := 1.0.0
-PKG_RELEASE := 5
+PKG_RELEASE := 6
 
 PKG_FULLVERSION := $(PKG_VERSION)-$(PKG_RELEASE)
 

README.md

@@ -268,6 +268,8 @@ Flags that do not scoped to a specific section, used over all the youtubeUnblock
 
 - `--udp-dport-filter=<5,6,200-500>` Filter the UDP destination ports. Defaults to no ports. Specifie the ports you want to be handled by youtubeUnblock.
 
+- `--udp-faking-strategy={checksum|ttl|none}` Faking strategy for udp. `checksum` will fake UDP checksum, `ttl` won't fake but will make UDP content relatively small, `none` is no faking. Defaults to none.
+
 - `--udp-filter-quic={disabled|all}` Enables QUIC filtering for UDP handler. If disabled, quic won't be processed, if all, all quic initial packets will be handled. Defaults to disabled.
 
 - `--quic-drop` Drop all QUIC packets which goes to youtubeUnblock. Won't affect any other UDP packets. Just an alias for `--udp-filter-quic=all --udp-mode=drop`.

args.c

@@ -347,7 +347,7 @@ void print_usage(const char *argv0) {
 	printf("\t--udp-mode={drop|fake}\n");
 	printf("\t--udp-fake-seq-len=<amount of faking packets sent>\n");
 	printf("\t--udp-fake-len=<size of upd fake>\n");
-	printf("\t--udp-faking-strategy={checksum|ttl}\n");
+	printf("\t--udp-faking-strategy={checksum|ttl|none}\n");
 	printf("\t--udp-dport-filter=<5,6,200-500>\n");
 	printf("\t--udp-filter-quic={disabled|all}\n");
 	printf("\t--threads=<threads number>\n");
@@ -709,6 +709,8 @@ int yparse_args(int argc, char *argv[]) {
 				sect_config->udp_faking_strategy = FAKE_STRAT_UDP_CHECK;
 			} else if (strcmp(optarg, "ttl") == 0) {
 				sect_config->udp_faking_strategy = FAKE_STRAT_TTL;
+			} else if (strcmp(optarg, "none") == 0) {
+				sect_config->udp_faking_strategy = FAKE_STRAT_NONE;
 			} else {
 				goto invalid_opt;
 			}
@@ -938,6 +940,11 @@ static size_t print_config_section(const struct section_config_t *section, char
 					break;
 				case FAKE_STRAT_TTL:
 					print_cnf_buf("--udp-faking-strategy=ttl");
+					print_cnf_buf("--faking-ttl=%d", section->faking_ttl);
+					break;
+				case 0:
+					print_cnf_buf("--udp-faking-strategy=none");
+					break;
 				}
 			}
 			break;

config.h

@@ -148,6 +148,7 @@ for (struct section_config_t *section = (config)->last_section; section != NULL;
 
 #define FAKE_TTL 8
 
+#define FAKE_STRAT_NONE		0
 // Will invalidate fake packets by out-of-ack_seq out-of-seq request
 #define FAKE_STRAT_RAND_SEQ	(1 << 0)
 // Will assume that GGC server is located further than FAKE_TTL
@@ -228,7 +229,7 @@ enum {
 	.udp_mode = UDP_MODE_FAKE,				\
 	.udp_fake_seq_len = 6,					\
 	.udp_fake_len = 64,					\
-	.udp_faking_strategy = FAKE_STRAT_UDP_CHECK,		\
+	.udp_faking_strategy = FAKE_STRAT_NONE,			\
 	.udp_dport_range = NULL,				\
 	.udp_dport_range_len = 0,				\
 	.udp_filter_quic = UDP_FILTER_QUIC_DISABLED,		\

mangle.c

@@ -383,6 +383,7 @@ int process_udp_packet(const struct section_config_t *section, const uint8_t *pk
 				.fake_len = section->udp_fake_len,
 				.strategy = {
 					.strategy = section->udp_faking_strategy,
+					.faking_ttl = section->faking_ttl,
 				},
 			};
 			ret = gen_fake_udp(fake_type, iph, iph_len, udph, fake_udp, &fsn_len);

quic.c

@@ -159,7 +159,7 @@ int udp_fail_packet(struct udp_failing_strategy strategy, uint8_t *payload, uint
 
 
 	if (strategy.strategy == FAKE_STRAT_TTL) {
-		lgtrace_addp("set fake ttl to %d", strategy.faking_ttl);
+		lgtrace_addp("Set fake ttl to %d", strategy.faking_ttl);
 
 		if (ipxv == IP4VERSION) {
 			((struct iphdr *)iph)->ttl = strategy.faking_ttl;
@@ -237,7 +237,8 @@ int gen_fake_udp(struct udp_fake_type type,
 
 	struct udphdr *nudph = (struct udphdr *)(buf + iph_len);
 	nudph->len = htons(sizeof(struct udphdr) + data_len);
-
+	
+	set_udp_checksum(nudph, buf, iph_len);
 
 	udp_fail_packet(type.strategy, buf, &dlen, *buflen);
 

utils.c

@@ -7,6 +7,7 @@
 #include <libnetfilter_queue/libnetfilter_queue_ipv4.h>
 #include <libnetfilter_queue/libnetfilter_queue_ipv6.h>
 #include <libnetfilter_queue/libnetfilter_queue_tcp.h>
+#include <libnetfilter_queue/libnetfilter_queue_udp.h>
 #else
 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 24))
 	#include <net/ip6_checksum.h>
@@ -31,6 +32,20 @@ void tcp4_set_checksum(struct tcphdr *tcph, struct iphdr *iph)
 #endif
 }
 
+void udp4_set_checksum(struct udphdr *udph, struct iphdr *iph) 
+{
+#ifdef KERNEL_SPACE
+	uint32_t udp_packet_len = ntohs(iph->tot_len) - (iph->ihl << 2);
+	udph->check = 0;
+	udph->check = csum_tcpudp_magic(
+		iph->saddr, iph->daddr, udp_packet_len,
+		IPPROTO_UDP, 
+		csum_partial(udph, udp_packet_len, 0));
+#else
+	nfq_udp_compute_checksum_ipv4(udph, iph);
+#endif
+}
+
 void ip4_set_checksum(struct iphdr *iph) 
 {
 #ifdef KERNEL_SPACE
@@ -52,6 +67,17 @@ void tcp6_set_checksum(struct tcphdr *tcph, struct ip6_hdr *iph) {
 #endif
 }
 
+void udp6_set_checksum(struct udphdr *udph, struct ip6_hdr *iph) {
+#ifdef KERNEL_SPACE
+	udph->check = 0;
+	udph->check = csum_ipv6_magic(&iph->saddr, &iph->daddr, 
+		 ntohs(iph->ip6_plen), IPPROTO_UDP, 
+		 csum_partial(udph, ntohs(iph->ip6_plen), 0));
+#else
+	nfq_udp_compute_checksum_ipv6(udph, iph);
+#endif
+}
+
 int set_ip_checksum(void *iph, uint32_t iphb_len) {
 	int ipvx = netproto_version(iph, iphb_len);
 
@@ -77,6 +103,21 @@ int set_tcp_checksum(struct tcphdr *tcph, void *iph, uint32_t iphb_len) {
 	return 0;
 }
 
+int set_udp_checksum(struct udphdr *udph, void *iph, uint32_t iphb_len) {
+	int ipvx = netproto_version(iph, iphb_len);
+
+	if (ipvx == IP4VERSION) {
+		udp4_set_checksum(udph, iph);
+	} else if (ipvx == IP6VERSION) {
+		udp6_set_checksum(udph, iph);
+	} else {
+		return -1;
+	}
+
+	return 0;
+}
+
+
 int ip4_payload_split(uint8_t *pkt, uint32_t buflen,
 		       struct iphdr **iph, uint32_t *iph_len, 
 		       uint8_t **payload, uint32_t *plen) {

utils.h

@@ -96,9 +96,12 @@ 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);
 void tcp6_set_checksum(struct tcphdr *tcph, struct ip6_hdr *iph);
+void udp4_set_checksum(struct udphdr *udph, struct iphdr *iph);
+void udp6_set_checksum(struct udphdr *udph, 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);
+int  set_udp_checksum(struct udphdr *udph, void *iph, uint32_t iphb_len);
 
 void z_function(const char *str, int *zbuf, size_t len);