prinet-proxy: Add keepalive module

Starts a separate thread that sends the keepalive packet to the
client in defined intervals

cmake/src/main/pumpnet/prinet-proxy/CMakeLists.txt

@@ -8,10 +8,11 @@ add_resources(PRI_PUBLIC_KEY ${SRC} prime.public.key)
 
 set(SOURCE_FILES
         ${SRC}/client.c
+        ${SRC}/keepalive.c
         ${SRC}/main.c
         ${SRC}/options.c
         ${SRC}/packet.c)
 
 add_executable(${PROJECT_NAME} ${SOURCE_FILES} ${PRI_PRIVATE_KEY} ${PRI_PUBLIC_KEY})
 
-target_link_libraries(${PROJECT_NAME} pumpnet-lib sec-prinet util)
+target_link_libraries(${PROJECT_NAME} pumpnet-lib sec-prinet util pthread)

src/main/pumpnet/prinet-proxy/keepalive.c

@@ -0,0 +1,84 @@
+#include <pthread.h>
+#include <stdatomic.h>
+
+#include "pumpnet/prinet-proxy/client.h"
+#include "pumpnet/prinet-proxy/keepalive.h"
+#include "pumpnet/prinet-proxy/packet.h"
+
+#include "util/log.h"
+#include "util/mem.h"
+#include "util/time.h"
+
+static struct pumpnet_prinet_proxy_client_connection* _pumpnet_prinet_proxy_client_connection;
+static uint32_t _pumpnet_prinet_proxy_keepalive_poll_ms;
+static pthread_t _pumpnet_prinet_proxy_keepalive_thread;
+static atomic_bool _pumpnet_prinet_proxy_keepalive_thread_run;
+
+static void* _pumpnet_prinet_proxy_keepalive_proc(void* ctx)
+{
+    struct pumpnet_prinet_proxy_packet* keepalive_packet;
+
+    log_debug("Keepalive thread started");
+
+    while (_pumpnet_prinet_proxy_keepalive_thread_run) {
+        // TODO we need to get the current CPU time and check if we have to do the below again
+        // reduce the sleep at the end of the loop to ensure this loop can exit easily
+
+        if (pumpnet_prinet_proxy_client_connection_is_active(_pumpnet_prinet_proxy_client_connection)) {
+            log_debug("Sending keepalive");
+
+            keepalive_packet = pumpnet_prinet_proxy_packet_create_keepalive();
+
+            size_t enc_data_len = sec_prinet_encrypt(
+                keepalive_packet->nounce,
+                sizeof(keepalive_packet->nounce),
+                keepalive_packet->data,
+                pumpnet_prinet_proxy_packet_get_data_len(keepalive_packet),
+                keepalive_packet->data);
+
+            keepalive_packet->length = pumpnet_prinet_proxy_packet_get_header_len() + enc_data_len;
+
+            if (!pumpnet_prinet_proxy_client_send_response(_pumpnet_prinet_proxy_client_connection, keepalive_packet)) {
+                log_error("Sending keepalive packet failed");
+            }
+
+            util_xfree((void**) &keepalive_packet);
+        } else {
+            log_debug("Skipped keepalive, no connection active");
+        }
+
+        //util_time_sleep_ms(500);
+        util_time_sleep_ms(_pumpnet_prinet_proxy_keepalive_poll_ms);
+    }
+
+    log_debug("Keep alive thread finished");
+
+    return NULL;
+}
+
+void pumpnet_prinet_proxy_keepalive_init(struct pumpnet_prinet_proxy_client_connection* connection, uint32_t poll_ms)
+{
+    _pumpnet_prinet_proxy_client_connection = connection;
+    _pumpnet_prinet_proxy_keepalive_poll_ms = poll_ms;
+
+    _pumpnet_prinet_proxy_keepalive_thread_run = true;
+
+    int result = pthread_create(
+        &_pumpnet_prinet_proxy_keepalive_thread,
+        NULL,
+        _pumpnet_prinet_proxy_keepalive_proc,
+        NULL);
+
+    if (result != 0) {
+        log_error("Creating keepalive thread failed: %s", strerror(result));
+    }
+
+    log_info("Started keepalive thread with polling every %d ms", poll_ms);
+}
+
+void pumpnet_prinet_proxy_keepalive_shutdown()
+{
+    _pumpnet_prinet_proxy_keepalive_thread_run = false;
+
+    pthread_join(_pumpnet_prinet_proxy_keepalive_thread, NULL);
+}

src/main/pumpnet/prinet-proxy/keepalive.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <stdint.h>
+
+#include "pumpnet/prinet-proxy/client.h"
+
+void pumpnet_prinet_proxy_keepalive_init(struct pumpnet_prinet_proxy_client_connection* connection, uint32_t poll_ms);
+
+void pumpnet_prinet_proxy_keepalive_shutdown();