If you want to send and receive on the same socket from two different threads, you’ll need to enable LWIP_NETCONN_FULLDUPLEX in opt.h (by default it’s not supported and feature is in alpha state):
/** LWIP_NETCONN_FULLDUPLEX==1: Enable code that allows reading from one thread, * writing from a 2nd thread and closing from a 3rd thread at the same time. * ATTENTION: This is currently really alpha! Some requirements: * - LWIP_NETCONN_SEM_PER_THREAD==1 is required to use one socket/netconn from * multiple threads at once * - sys_mbox_free() has to unblock receive tasks waiting on recvmbox/acceptmbox * and prevent a task pending on this during/after deletion */ #if !defined LWIP_NETCONN_FULLDUPLEX || defined __DOXYGEN__ #define LWIP_NETCONN_FULLDUPLEX 0 #endif Joel > On Jan 25, 2017, at 1:02 AM, Neerav Patel <neeravpa...@hotmail.com> wrote: > > Hi, > > I read that same statement after I had posted and so I created another system > thread (been debugging the whole day): > > sys_thread_new("handle_thread", handle_thread, NULL, 400, 3); > > and tried to send from it, and it also hung in the same way, seems to not > return from a semaphore call deep in the bowls of lwip, still digging further > into it. > > Maybe this will do the same and call back from the tcpipthread. > > How would you propose structuring the code, I want one thread to receive > packets and another to send out? Is creating a system thread the right way > to go? Why would I be hanging with the code below? > > Thanks for all the help! > > void > handle_thread( ) > { > while ( 1 ) > { > if ( send_actual_pkt ) > { > send_actual_pkt = 0; > uint8_t pkt[576]; > // ... populate the pkt > uint16_t len = generate_pkt(); > if ( lwip_sendto( s, pkt, len, 0, (struct sockaddr *)&from, > sizeof(from) ) != len ) <---- hanging here!!!! > { > uart_printf( "Didnt send correctly %x\n", len ); > } > } > } > } > > > while( 1 ) > { > if ( (lwip_recvfrom(s, raw_buf, sizeof(raw_buf), 0, (struct > sockaddr*)&from, (socklen_t*)&fromlen)) > 0 ) > { > send_actual_pkt = 1; > } > } > > > > From: lwip-users <lwip-users-bounces+neeravpatel=hotmail....@nongnu.org > <mailto:lwip-users-bounces+neeravpatel=hotmail....@nongnu.org>> on behalf of > Dirk Ziegelmeier <d...@ziegelmeier.net <mailto:d...@ziegelmeier.net>> > Sent: January 25, 2017 6:48 AM > To: Mailing list for lwIP users > Subject: Re: [lwip-users] lwip_sendto hanging with lwip 2.0 > > Calling sys_timeout() results in send_actual_pkt being called back from TCPIP > thread. You must not call sequencial style functions from TCPIP thread. > > http://www.nongnu.org/lwip/2_0_0/group__sequential__api.html > <http://www.nongnu.org/lwip/2_0_0/group__sequential__api.html> says: "More > overhead, but can be called from any thread except TCPIP thread." > lwIP: Sequential-style APIs - nongnu.org > <http://www.nongnu.org/lwip/2_0_0/group__sequential__api.html> > www.nongnu.org <http://www.nongnu.org/> > Detailed Description. Sequential-style APIs, blocking functions. More > overhead, but can be called from any thread except TCPIP thread. > > > > Dirk > > _______________________________________________ > lwip-users mailing list > lwip-users@nongnu.org <mailto:lwip-users@nongnu.org> > https://lists.nongnu.org/mailman/listinfo/lwip-users > <https://lists.nongnu.org/mailman/listinfo/lwip-users>
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