Add ping support

1 files changed, 84 insertions, 0 deletions

diff --git a/src/query.c b/src/query.c
new file mode 100644
index 0000000..5645271
--- /dev/null
+++ b/src/query.c
@@ -0,0 +1,84 @@
+#include "query.h"
+#include "benc.h"
+#include "log.h"
+
+#include <string.h>
+#include <errno.h>
+
+int handle_request(struct nodeid* self, const char* method, const char* packet, size_t packet_len, char** response, size_t response_len) {
+	if(strcmp(method, "ping") == 0) {
+		struct bcursor bcursor;
+		struct benc_node stream[256];
+		bcur_open(&bcursor, packet, packet+packet_len, stream, 256);
+
+		if(bcursor.readhead->type != BNT_DICT) {
+			err("Bad query: Packet is not a dict");
+			return QUERY_EBADQ;
+		}
+		if(bcur_next(&bcursor, 1) < 0) {
+			err("Bad query: No token after outer dict start");
+			return QUERY_EBADQ;
+		}
+
+		if(bcur_find_key(&bcursor, (const enum benc_nodetype[]){BNT_STRING}, (const char*[]){"a"}, (const size_t[]){1}, 1) != 0) {
+			err("Bad query: No arguments to request");
+			return QUERY_EBADQ;
+		}
+		bcur_next(&bcursor, 1);
+		if(bcursor.readhead->type != BNT_DICT) {
+			err("Bad query: Wrong value type for request");
+			return QUERY_EBADQ;
+		}
+		// Skip the dict element
+		bcur_next(&bcursor, 1);
+		bool source_set = false;
+		struct nodeid source_id;
+		while(bcursor.readhead->type != BNT_END) {
+			switch(bcur_find_key(&bcursor, (const enum benc_nodetype[]){BNT_STRING}, (const char*[]){"id"}, (const size_t[]){6}, 1)) {
+				case 0:
+					// Skip the key
+					bcur_next(&bcursor, 1);
+
+					if(bcursor.readhead->type != BNT_STRING) {
+						err("Bad query: Wrong value type for id");
+						return QUERY_EBADQ;
+					}
+
+					if(bcursor.readhead->size != 20) {
+						err("Bad query: Incorrect id length");
+						return QUERY_EBADQ;
+					}
+
+					source_set = true;
+					memcpy(&source_id, bcursor.readhead->loc, 20);
+
+					// Skip the value
+					bcur_next(&bcursor, 1);
+					break;
+			}
+		}
+
+		if(!source_set) {
+			err("Id argument not set");
+			return QUERY_EBADQ;
+		}
+
+		char* end = (*response) + response_len;
+
+		int rc = snprintf(*response, end-*response, "d2:id20:");
+		if(rc < 0)
+			return QUERY_EBADQ;
+		*response += rc;
+		memcpy(*response, self, sizeof(struct nodeid));
+		*response += sizeof(struct nodeid);
+		rc = snprintf(*response, end-*response, "ee");
+		if(rc < 0)
+			return QUERY_EBADQ;
+		*response += rc;
+	} else {
+		return QUERY_EUNK;
+	}
+
+	return 0;
+}
+