UDP transmission mode not stable

[MuNianCi]

Describe the bug
When conducting long-term send and receive tests using the UDP transmission mode of the NNG protocol, after node A receives a message from node B, it sends it back to A unchanged. After sending and receiving approximately 30,000,000 packets of data, each 1024 bytes in size, the sender stops sending application layer data. Packet capture reveals that only messages like CREQ are still being transmitted.

When using the pipeline mode, if the pull end terminates the process using Ctrl + C, and then multiple restarts are performed, a core dump issue may occur.

I'll provide source code of my demos later.

[xiebingjun777]

hi, could you provide your demo code for me. i need to use UDP mode recently. Thank!

[gdamore]

UDP mode is experimental, and I'm going to make some rather significant simplifications to it soon. The net result of those will be that some protections against replays and reorders will be lost, but that's what you get with UDP.

[MuNianCi]

Here's my demo. When I send messages without adding a delay, the push end experiences a coredump after the pull end terminates its process.
PUSH

#include <stdlib.h>
#include <string.h>
#include <nng/nng.h>
#include <unistd.h>

int main(int argc, char **argv)
{
if(argc < 2){
fprintf(stderr, "%s \n", argv[0]);
return 0;
}
char *URL = argv[1];
nng_socket sock;
int rv;
nng_init(NULL);
if ((rv = nng_push0_open(&sock)) != 0) {
fprintf(stderr, "nng_push0_open: %s\n", nng_strerror(rv));
return 1;
}

if ((rv = nng_listen(sock, URL, NULL, 0)) != 0) {
    fprintf(stderr, "nng_listen: %s\n", nng_strerror(rv));
    return 1;
}

for (int i = 0; i < 5000000; i++) {
    char msg[128];
    memset(msg, 'A', sizeof(msg) -1);

    if ((rv = nng_send(sock, msg, strlen(msg) + 1, 0)) != 0) {
        fprintf(stderr, "nng_send: %s\n", nng_strerror(rv));
    } else {
        printf("Sent: %s\n", msg);
    }
    //When I comment out the following line and restart 
    //the pull-side demo several times, a coredump occurs.
    usleep(100); 
}

nng_socket_close(sock);
return 0;

}

PULL
#include <stdio.h>
#include <stdlib.h>
#include <nng/nng.h>

int main(int argc, char **argv)
{
if(argc < 2){
fprintf(stderr, "%s \n", argv[0]);
return 0;
}

char *URL = argv[1];

nng_socket sock;
int rv;
            nng_init(NULL);
if ((rv = nng_pull0_open(&sock)) != 0) {
    fprintf(stderr, "nng_pull0_open: %s\n", nng_strerror(rv));
    return 1;
}

if ((rv = nng_dial(sock, URL, NULL, 0)) != 0) {
    fprintf(stderr, "nng_dial: %s\n", nng_strerror(rv));
    return 1;
}

for (int i = 0; i < 50000; i++) {
    char buf[1024] = {0};
    size_t sz;

    if ((rv = nng_recv(sock, &buf, &sz, 0)) != 0) {
        fprintf(stderr, "nng_recv: %s\n", nng_strerror(rv));
    } else {
        printf("Received: %s\n", buf);
    }
}

nng_socket_close(sock);
return 0;

}

coredump notice
panic: pthread_mutex_lock: Invalid argument
This message is indicative of a BUG.
Report this at https://github.com/nanomsg/nng/issues
/usr/local/lib/libnng.so.1(+0x206c3) [0x7fd6e00756c3]
/usr/local/lib/libnng.so.1(+0x341c1) [0x7fd6e00891c1]
/usr/local/lib/libnng.so.1(+0x3439e) [0x7fd6e008939e]
/usr/local/lib/libnng.so.1(+0x28a7b) [0x7fd6e007da7b]
/usr/local/lib/libnng.so.1(+0x27ce3) [0x7fd6e007cce3]
/usr/local/lib/libnng.so.1(+0x17057) [0x7fd6e006c057]
/usr/local/lib/libnng.so.1(+0x1708f) [0x7fd6e006c08f]
/usr/local/lib/libnng.so.1(+0x5190d) [0x7fd6e00a690d]
/usr/local/lib/libnng.so.1(+0x2097d) [0x7fd6e007597d]
/usr/local/lib/libnng.so.1(+0x3b2af) [0x7fd6e00902af]
/usr/local/lib/libnng.so.1(+0x23456) [0x7fd6e0078456]
/usr/local/lib/libnng.so.1(nng_sendmsg+0xf8) [0x7fd6e0066e2f]
/usr/local/lib/libnng.so.1(nng_send+0x80) [0x7fd6e0066d09]
./a.out(+0x1411) [0x5557875a3411]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf3) [0x7fd6dfe87083]
./a.out(+0x11ce) [0x5557875a31ce]
Aborted

[MuNianCi]

hi, could you provide your demo code for me. i need to use UDP mode recently. Thank!
Here are my demo and the coredump prompt.
#2127 (comment)

[gdamore]

Can you please try again with what is in the main branch. I've refactored it quite a lot.