From 42956e1602c569841f15f37ea83faf9af3bd1b25 Mon Sep 17 00:00:00 2001
From: lijia <lijia01@iie.ac.cn>
Date: Thu, 15 Nov 2018 11:25:34 +0800
Subject: [PATCH] =?UTF-8?q?=E5=A2=9E=E5=8A=A0-g=E5=8F=82=E6=95=B0,=20?=
 =?UTF-8?q?=E5=B9=B6=E9=80=9A=E8=BF=87=E6=8E=A7=E5=88=B6=E8=BF=9E=E6=8E=A5?=
 =?UTF-8?q?=E4=BC=A0=E8=BE=93=E7=BB=99sapp.?=
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---
 mesa_pkt_dump.h |  4 ++++
 tcpdump.c       | 30 +++++++++++++++++++++++++++---
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/mesa_pkt_dump.h b/mesa_pkt_dump.h
index 5abc7ff..7dedb4b 100644
--- a/mesa_pkt_dump.h
+++ b/mesa_pkt_dump.h
@@ -1,6 +1,9 @@
 #ifndef _MESA_PKT_DUMP_H_
 #define _MESA_PKT_DUMP_H_ 1
 
+#define MESA_PKT_DUM_H_VER (20181115)
+
+
 /* 
 	用于DPDK-3.0, PFRING模式下, 驱动独占网卡时, 通过平台实时捕包.
 */
@@ -14,6 +17,7 @@ enum pkt_dump_opt_t{
 	PKT_DUMP_OPT_THREAD_INDEX,
 	PKT_DUMP_OPT_ACK, /* sapp返回给tcpdump_mesa的ack包 */
 	PKT_DUMP_OPT_PERCEPTIVE, /* 明察秋毫模式, 可以发现丢包数量 */
+	PKT_DUMP_OPT_GREEDY_SEEK,  /* 偏移到最内层IP, 便于隧道模式下查找BUG */ 
 };
 
 /* 网络序, 便于以后在其他系统如ARM, PowerPC, MIPS上移植 */
diff --git a/tcpdump.c b/tcpdump.c
index 246805a..a890e07 100644
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -959,7 +959,11 @@ static int pkt_dump_recv_ack(int connfd)
 }
 
 #include <pthread.h>
-static void *detect_sapp_thread(void *arg)
+/*
+	此线程用于监测sapp的控制连接是否存活, 如果sapp退出了,
+	tcpdump_mesa也应该退出.
+*/
+static void *detect_sapp_alive_thread(void *arg)
 {
 	int tcp_cmd_fd = (int)arg;
 	int ret;
@@ -1020,9 +1024,17 @@ static int MESA_dump_start(unsigned short udp_rcv_port, unsigned short sapp_cmd_
 		opt_num++;
 	}
 
+	if(greedy_seek_flag != 0){
+		if(tcpdump_data_offset != 0){
+			printf("option -o and -g is exclusive, can't use at same time!\n");
+			exit(1);
+		}
+		opt_num++;
+	}
+
 	/************** pkt handshake *************/
 	pkt_hdr.magic = htonl(PKT_DUMP_HDR_MAGIC);
-	pkt_hdr.version = htonl(tcpdump_mesa_version_VERSION_20181114);
+	pkt_hdr.version = htonl(20180119); /* 之前sapp对20180119版本做了严格校验, 此处向后兼容, 先固定用此值, 以后更新sapp后, 不再校验版本 */
 	pkt_hdr.opt_num = htonl(opt_num);
 	ret = write(tcp_cmd_fd, &pkt_hdr, sizeof(pkt_hdr));
 	if(ret < 0){
@@ -1106,12 +1118,24 @@ static int MESA_dump_start(unsigned short udp_rcv_port, unsigned short sapp_cmd_
 		}
 	}
 
+	/************** greedy seek *************/
+	if(greedy_seek_flag != 0){
+		opt.opt_type = htons(PKT_DUMP_OPT_GREEDY_SEEK);
+		opt.opt_len = 0;
+		ret = write(tcp_cmd_fd, &opt, sizeof(opt));
+		if(ret < 0){
+			printf("connection down!\n");
+			exit(1);
+		}
+	}
+
+	/********** after send opt, start recv sapp ACK *******/
 	if(pkt_dump_recv_ack(tcp_cmd_fd) < 0){
 		printf("connection down!\n");
 		exit(1);
 	}
 
-	pthread_create(&pid, NULL, detect_sapp_thread, (void *)tcp_cmd_fd);
+	pthread_create(&pid, NULL, detect_sapp_alive_thread, (void *)tcp_cmd_fd);
 
 	return tcp_cmd_fd;
 }