Ralink wifi driver WPA四次握手可能的问题

测试在MT7620A上跑openwrt；router模式下，手机连接MT7620A板子就是失败。

 

经过分析发现：

在ralink的wifi driver中WPA成对密钥的四次握手，以及组密钥协商信令过程，

如果AP未及时收到client回复的信令，可能会主动踢掉client，或者很快重发WPA成对密钥的第一个信令；

如果使用iwpriv ra0 set Debug=3  输出更多log信息的话，会看到client反复不停连接AP，log中有很多如下的信息

WPARetryExec---> ReTryCounter

因此确实因为某些原因处理速度慢的话，可以考虑修改AP这边的以下代码。 不过也可能是其他原因造成的wifi driver处理速度太慢，需要进一步深究。

 

VOID WPARetryExec(
    IN PVOID SystemSpecific1, 
    IN PVOID FunctionContext, 
    IN PVOID SystemSpecific2, 
    IN PVOID SystemSpecific3) 
{
    MAC_TABLE_ENTRY     *pEntry = (MAC_TABLE_ENTRY *)FunctionContext;

    if ((pEntry) && IS_ENTRY_CLIENT(pEntry))
    {
        PRTMP_ADAPTER pAd = (PRTMP_ADAPTER)pEntry->pAd;

        pEntry->ReTryCounter++;
        DBGPRINT(RT_DEBUG_TRACE, ("WPARetryExec---> ReTryCounter=%d, WpaState=%d \n", pEntry->ReTryCounter, pEntry->WpaState));

        switch (pEntry->AuthMode)
        {
            case Ndis802_11AuthModeWPA:
            case Ndis802_11AuthModeWPAPSK:
            case Ndis802_11AuthModeWPA2:
            case Ndis802_11AuthModeWPA2PSK:
                /* 1. GTK already retried, give up and disconnect client. */
                if (pEntry->ReTryCounter > (GROUP_MSG1_RETRY_TIMER_CTR + 1))
                {    
                    /* send wireless event - for group key handshaking timeout */
                    RTMPSendWirelessEvent(pAd, IW_GROUP_HS_TIMEOUT_EVENT_FLAG, pEntry->Addr, pEntry->apidx, 0); 

                    DBGPRINT(RT_DEBUG_TRACE, ("WPARetryExec::Group Key HS exceed retry count, Disassociate client, pEntry->ReTryCounter %d\n", pEntry->ReTryCounter));
                    MlmeDeAuthAction(pAd, pEntry, REASON_GROUP_KEY_HS_TIMEOUT, FALSE);
                }
                /* 2. Retry GTK. */
                else if (pEntry->ReTryCounter > GROUP_MSG1_RETRY_TIMER_CTR)
                {
                    DBGPRINT(RT_DEBUG_TRACE, ("WPARetryExec::ReTry 2-way group-key Handshake \n"));
                    if (pEntry->GTKState == REKEY_NEGOTIATING)
                    {
                        WPAStart2WayGroupHS(pAd, pEntry);
                        RTMPSetTimer(&pEntry->RetryTimer, PEER_MSG3_RETRY_EXEC_INTV);
                    }
                }
                /* 3. 4-way message 1 retried more than three times. Disconnect client */
                else if (pEntry->ReTryCounter > (PEER_MSG1_RETRY_TIMER_CTR + 3))
                {
                    /* send wireless event - for pairwise key handshaking timeout */
                    RTMPSendWirelessEvent(pAd, IW_PAIRWISE_HS_TIMEOUT_EVENT_FLAG, pEntry->Addr, pEntry->apidx, 0);

                    DBGPRINT(RT_DEBUG_TRACE, ("WPARetryExec::MSG1 timeout, pEntry->ReTryCounter = %d\n", pEntry->ReTryCounter));
                    MlmeDeAuthAction(pAd, pEntry, REASON_4_WAY_TIMEOUT, FALSE);
                }
                /* 4. Retry 4 way message 1, the last try, the timeout is 3 sec for EAPOL-Start */
                else if (pEntry->ReTryCounter == (PEER_MSG1_RETRY_TIMER_CTR + 3))                
                {
                    DBGPRINT(RT_DEBUG_TRACE, ("WPARetryExec::Retry MSG1, the last try\n"));
                    WPAStart4WayHS(pAd , pEntry, PEER_MSG3_RETRY_EXEC_INTV);
                }
                /* 4. Retry 4 way message 1 */
                else if (pEntry->ReTryCounter < (PEER_MSG1_RETRY_TIMER_CTR + 3))
                {
                    if ((pEntry->WpaState == AS_PTKSTART) || (pEntry->WpaState == AS_INITPSK) || (pEntry->WpaState == AS_INITPMK))
                    {
                        DBGPRINT(RT_DEBUG_TRACE, ("WPARetryExec::ReTry MSG1 of 4-way Handshake\n"));
                        WPAStart4WayHS(pAd, pEntry, PEER_MSG1_RETRY_EXEC_INTV);
                    }
                }
                break;

            default:
                break;
        }
    }

 

尝试做的一些修改，简单试了一下，可以解决一些问题，供参考：

 

/* 3. 4-way message 1 retried more than three times. Disconnect client */
                //else if (pEntry->ReTryCounter > (PEER_MSG1_RETRY_TIMER_CTR + 3))
                else if ( 
                    ( (pEntry->ReTryCounter > (PEER_MSG1_RETRY_TIMER_CTR + 3))
                    && (pEntry->ReTryCounter < PEER_MSG3_RETRY_TIMER_CTR) )
                    || 
                    ( (pEntry->ReTryCounter > (PEER_MSG3_RETRY_TIMER_CTR + 3))
                    && (pEntry->ReTryCounter < GROUP_MSG1_RETRY_TIMER_CTR) )
                    )
                {
                    /* send wireless event - for pairwise key handshaking timeout */
                    RTMPSendWirelessEvent(pAd, IW_PAIRWISE_HS_TIMEOUT_EVENT_FLAG, pEntry->Addr, pEntry->apidx, 0);

                    DBGPRINT(RT_DEBUG_TRACE, ("WPARetryExec::MSG1 or MSG3 timeout, pEntry->ReTryCounter = %d\n", pEntry->ReTryCounter));
                    MlmeDeAuthAction(pAd, pEntry, REASON_4_WAY_TIMEOUT, FALSE);
                }

 

/* 4. Retry 4 way message 1 */
                else if (pEntry->ReTryCounter < (PEER_MSG1_RETRY_TIMER_CTR + 3))
                {
                    if ((pEntry->WpaState == AS_PTKSTART) || (pEntry->WpaState == AS_INITPSK) || (pEntry->WpaState == AS_INITPMK))
                    {
                        //DBGPRINT(RT_DEBUG_TRACE, ("WPARetryExec::ReTry MSG1 of 4-way Handshake\n"));
                        //WPAStart4WayHS(pAd, pEntry, PEER_MSG1_RETRY_EXEC_INTV);
                    }
                }