doubango TURN Data Indication报文代码

Posted 2021-09-05 柳鲲鹏

　　朋友委托分析一下，吾让其抓了两个报文（成功与失败）对比。

• 第一步，看报文的差异

经过分析，流程上无明显差异，最大的不同是失败报文中没有Data Indication报文。

• 学习一下TURN

要想由TURN服务器转发，必须终端发Data Indication报文，服务器回一个Send Indication报文。这样看来，就是终端的报文有问题。

• 分析Data Indication

失败报文多了32字节。其中有内容：

IM-client/OMA1.0 doubango/v2.0.0

看看代码，哪里使用这个字串。

• 搜索字串

$ grep -rn "OMA1.0"
tinynet_config.h:124:#define TNET_SOFTWARE	"IM-client/OMA1.0 doubango/v2.0.0"

$ grep -rn TNET_SOFTWARE
stun/tnet_stun_types.h:78:#	define kStunSoftware TNET_SOFTWARE

$ grep -rn kStunSoftware

# stun
stun/tnet_stun_binding.c:74:                                  TNET_STUN_PKT_ATTR_ADD_SOFTWARE_ZT(kStunSoftware),

# turn
turn/tnet_turn_session.c:635:                                  TNET_STUN_PKT_ATTR_ADD_SOFTWARE_ZT(kStunSoftware), // recommended for Alloc and Refresh
turn/tnet_turn_session.c:1396:                                  TNET_STUN_PKT_ATTR_ADD_SOFTWARE_ZT(kStunSoftware),  // recommended for Alloc and Refresh

# ice
ice/tnet_ice_candidate.c:576:                                  TNET_STUN_PKT_ATTR_ADD_SOFTWARE_ZT(kStunSoftware),
ice/tnet_ice_pair.c:287:                                      TNET_STUN_PKT_ATTR_ADD_SOFTWARE_ZT(kStunSoftware),
ice/tnet_ice_pair.c:421:                                      TNET_STUN_PKT_ATTR_ADD_SOFTWARE_ZT(kStunSoftware),
ice/tnet_ice_ctx.c:620:            

已知服务器是TURN，自然就知道应该是tnet_net_session.c

• 再搜索ndication

$ grep -rn ndication

# send indication
tnet_turn_session.c:1054:    /*** Send indication ***/
tnet_turn_session.c:1056:        if ((ret = tnet_stun_pkt_create_empty(tnet_stun_pkt_type_send_indication, &pc_peer->p_pkt_sendind))) {
tnet_turn_session.c:1057:            TSK_DEBUG_ERROR("Failed to create TURN SendIndication request");

tnet_turn.c:211://tnet_stun_pkt_req_t* tnet_turn_create_request_sendindication(const tnet_nat_context_t* context, tnet_turn_allocation_t* allocation, va_list *app)
tnet_turn.c:213://	tnet_stun_pkt_req_t* request =  tnet_turn_create_request(context, allocation, stun_send_indication);
tnet_turn.c:221://			draft-ietf-behave-turn-16 - 10.1.  Forming a Send Indication
tnet_turn.c:223://			When forming a Send indication, the client MUST include a XOR-PEER-

tnet_turn.c:497://		if(indication)
tnet_turn.c:499://			if((ret = tnet_turn_send_request(nat_context, (tnet_turn_allocation_t*)channel_bind->allocation, tnet_turn_create_request_sendindication, channel_bind->xpeer, data, size)))
tnet_turn.c:501://				TSK_DEBUG_ERROR("TURN channel send indication failed with error code:%d.", ret);

# data indication
tnet_turn_session.c:1963:    case tnet_stun_pkt_type_data_indication: {
tnet_turn_session.c:2220:        if (p_pkt->e_type == tnet_stun_pkt_type_data_indication) {
tnet_turn.h:168://int tnet_turn_channel_senddata(const struct struct tnet_nat_ctx_s* nat_context, const tnet_turn_channel_binding_t * channel_bind, const void* data, tsk_size_t size, int indication);
tnet_turn.c:488://int tnet_turn_channel_senddata(const struct struct tnet_nat_ctx_s* nat_context, const tnet_turn_channel_binding_t * channel_bind, const void* data, tsk_size_t size, int indication)


# ignore
tnet_turn_session.c:157:        tsk_timer_id_t u_timer_id_refresh; // To refresh Alloc (Send Refresh Indication)
tnet_turn_session.c:1375:    // create RefreshIndication Request
tnet_turn_session.c:1379:        TSK_DEBUG_ERROR("Failed to create TURN RefreshIndication request");
tnet_turn_session.c:1949:    case tnet_stun_pkt_type_connectionattempt_indication: {
tnet_turn_session.c:1990:    if (pc_pkt->e_type != tnet_stun_pkt_type_connectionattempt_indication && !TNET_STUN_PKT_RESP_IS_SUCCESS(pc_pkt)) {