feature impls + directories

1 files changed, 163 insertions, 0 deletions

diff --git a/src/plugin.c b/src/plugin.c
new file mode 100644
index 0000000..cfee5d4
--- /dev/null
+++ b/src/plugin.c
@@ -0,0 +1,163 @@
+#pragma once
+
+#include <dlfcn.h>
+#include <pthread.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+//
+#include "common.c"
+
+typedef uint8_t byte;
+
+// contracts
+
+void                               __init_plugin_func(void);
+typedef typeof(__init_plugin_func) init_plugin;
+
+struct relay_info;
+struct relay_neighbor;
+struct data_packet;
+
+// runs when the server wants to respond to a server audit request
+void __modify_server_stats_func(struct relay_info *server_stats);
+typedef typeof(__modify_server_stats_func) modify_server_stats;
+
+// runs when the server wants to decide whether to add a neighbor by request or not
+bool __decide_neighbor_registry_func(struct relay_neighbor new_neighbor);
+typedef typeof(__decide_neighbor_registry_func) decide_neighbor_registry;
+
+// runs when the server wants to decide whether to propagate
+bool __decide_packet_propogation_func(struct data_packet packet);
+typedef typeof(__decide_packet_propogation_func) decide_packet_propogation;
+
+// runs before the paste_server function performs any logic
+void __paste_server_start_func(
+    char   **ip_addr_ref,
+    size_t  *ip_size_ref,
+    byte   **in_ref,
+    size_t  *in_len_ref,
+    byte  ***out_ref,
+    size_t **out_len_ref);
+typedef typeof(__paste_server_start_func) paste_server_start;
+
+// runs when the server wants to decide whether to save the packet to disk
+bool __decide_packet_save_to_disk_func(struct data_packet packet);
+typedef typeof(__decide_packet_save_to_disk_func) decide_packet_save_to_disk;
+
+// runs when the server wants a plugin to modify a packet (e.g., keepalive, run PoW, etc)
+void                                 __modify_packet_func(struct data_packet *packet);
+typedef typeof(__modify_packet_func) modify_packet;
+
+// runs when the server wants to decide whether to wipe a packet
+bool __decide_packet_cleanup_func(struct data_packet packet);
+typedef typeof(__decide_packet_cleanup_func) decide_packet_cleanup;
+
+// runs when the server logs a message
+void                              __custom_log_func(int level, const char *msg);
+typedef typeof(__custom_log_func) custom_log;
+
+// runs when the server is shutting down
+void                                      __on_server_shutdown_func(void);
+typedef typeof(__on_server_shutdown_func) on_server_shutdown;
+
+// data
+
+enum plugin_handler_code_types {
+    code_modify_server_stats        = 1,
+    code_decide_neighbor_registry   = 2,
+    code_decide_packet_propogation  = 3,
+    code_paste_server_start         = 4,
+    code_decide_packet_save_to_disk = 5,
+    code_modify_packet              = 6,
+    code_decide_packet_cleanup      = 7,
+    code_on_server_shutdown         = 8,
+    code_custom_log                 = 9
+};
+
+void                       *plugin_handle                   = NULL;
+init_plugin                *init_plugin_func                = NULL;
+modify_server_stats        *modify_server_stats_func        = NULL;
+decide_neighbor_registry   *decide_neighbor_registry_func   = NULL;
+decide_packet_propogation  *decide_packet_propogation_func  = NULL;
+paste_server_start         *paste_server_start_func         = NULL;
+decide_packet_save_to_disk *decide_packet_save_to_disk_func = NULL;
+modify_packet              *modify_packet_func              = NULL;
+decide_packet_cleanup      *decide_packet_cleanup_func      = NULL;
+custom_log                 *custom_log_func                 = NULL;
+on_server_shutdown         *on_server_shutdown_func         = NULL; // unused for now
+
+pthread_mutex_t plugin_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+// implementation
+
+void load_plugins(const char *plugin_path) {
+    pthread_mutex_lock(&plugin_mutex);
+    if (plugin_handle) {
+        dlclose(plugin_handle);
+        plugin_handle                   = NULL;
+        init_plugin_func                = NULL;
+        modify_server_stats_func        = NULL;
+        decide_neighbor_registry_func   = NULL;
+        decide_packet_propogation_func  = NULL;
+        paste_server_start_func         = NULL;
+        decide_packet_save_to_disk_func = NULL;
+        modify_packet_func              = NULL;
+        decide_packet_cleanup_func      = NULL;
+        custom_log_func                 = NULL;
+        on_server_shutdown_func         = NULL;
+    }
+
+    plugin_handle = dlopen(plugin_path, RTLD_NOW);
+    if (!plugin_handle) {
+        fprintf(stderr, "%s\n", dlerror());
+        pthread_mutex_unlock(&plugin_mutex);
+        return;
+    }
+
+    if (init_plugin_func) {
+        init_plugin_func();
+        log(_info, "loaded %s\n", plugin_path);
+    } else {
+        log(_error, "%s has no MP_init_plugin", plugin_path);
+        dlclose(plugin_handle);
+        plugin_handle = NULL;
+        pthread_mutex_unlock(&plugin_mutex);
+        return;
+    }
+
+    init_plugin_func                = dlsym(plugin_handle, "MP_init_plugin");
+    modify_server_stats_func        = dlsym(plugin_handle, "MP_modify_server_stats");
+    decide_neighbor_registry_func   = dlsym(plugin_handle, "MP_decide_neighbor_registry");
+    decide_packet_propogation_func  = dlsym(plugin_handle, "MP_decide_packet_propogation");
+    paste_server_start_func         = dlsym(plugin_handle, "MP_paste_server_start");
+    decide_packet_save_to_disk_func = dlsym(plugin_handle, "MP_decide_packet_save_to_disk");
+    modify_packet_func              = dlsym(plugin_handle, "MP_modify_packet");
+    decide_packet_cleanup_func      = dlsym(plugin_handle, "MP_decide_packet_cleanup");
+    custom_log_func                 = dlsym(plugin_handle, "MP_custom_log");
+    on_server_shutdown_func         = dlsym(plugin_handle, "MP_on_server_shutdown");
+
+    pthread_mutex_unlock(&plugin_mutex);
+}
+
+void cleanup_plugins(void) {
+    pthread_mutex_lock(&plugin_mutex);
+    if (plugin_handle) {
+        if (on_server_shutdown_func) { on_server_shutdown_func(); }
+        dlclose(plugin_handle);
+        plugin_handle                   = NULL;
+        init_plugin_func                = NULL;
+        modify_server_stats_func        = NULL;
+        decide_neighbor_registry_func   = NULL;
+        decide_packet_propogation_func  = NULL;
+        paste_server_start_func         = NULL;
+        decide_packet_save_to_disk_func = NULL;
+        modify_packet_func              = NULL;
+        decide_packet_cleanup_func      = NULL;
+        custom_log_func                 = NULL;
+        on_server_shutdown_func         = NULL;
+    }
+    pthread_mutex_unlock(&plugin_mutex);
+}