TSG-13175 Decrypted Traffic Steering构造的SYN/SYN ACK支持MSS选项

1 files changed, 31 insertions, 3 deletions

diff --git a/platform/src/acceptor_kni_v3.cpp b/platform/src/acceptor_kni_v3.cpp
index 05628d9..03f19ad 100644
--- a/platform/src/acceptor_kni_v3.cpp
+++ b/platform/src/acceptor_kni_v3.cpp
@@ -278,13 +278,19 @@ static void tcp_restore_info_parse_from_pkt(struct pkt_info *pktinfo, struct tcp
 	}
 }
 
-struct tcp_option_window_scale{
+struct tcp_option_mss {
+	uint8_t kind;
+	uint8_t length;
+	uint16_t mss_value;
+};
+
+struct tcp_option_window_scale {
 	uint8_t kind;
 	uint8_t length;
 	uint8_t shift_count;
 };
 
-struct tcp_option_sack{
+struct tcp_option_sack {
 	uint8_t kind;
 	uint8_t length;
 };
@@ -316,7 +322,29 @@ static int fake_tcp_handshake(struct tfe_proxy *proxy, struct tcp_restore_info *
 	uint32_t s_seq = server->seq - 1;
 
 	/*
-	 * Window Scale option (WSopt): Kind: 3, Length: 3
+	 * Maximum segment size: Kind: 2, Length: 4
+	 * +---------+---------+---------+
+	 * | Kind=2  |Length=4 |mss.value|
+	 * +---------+---------+---------+
+	 *      1         1         2
+	 */
+	if (client->mss && server->mss)
+	{
+		struct tcp_option_mss *option_c = (struct tcp_option_mss *)(tcp_option_buffer_c + tcp_option_length_c);
+		option_c->kind = 2;
+		option_c->length = 4;
+		option_c->mss_value = htons(client->mss);
+		tcp_option_length_c += sizeof(struct tcp_option_mss);
+
+		struct tcp_option_mss *option_s = (struct tcp_option_mss *)(tcp_option_buffer_s + tcp_option_length_s);
+		option_s->kind = 2;
+		option_s->length = 4;
+		option_s->mss_value = htons(server->mss);
+		tcp_option_length_s += sizeof(struct tcp_option_mss);
+	}
+
+	/*
+	 * Window Scale option: Kind: 3, Length: 3
 	 * +---------+---------+---------+
 	 * | Kind=3  |Length=3 |shift.cnt|
 	 * +---------+---------+---------+