implement receiving and parsing NG protocol packets

daemon/aux.h

@@ -146,6 +146,14 @@ static inline int smart_pton(int af, char *src, void *dst) {
 	return inet_pton(af, src, dst);
 }
 
+static inline int strmemcmp(const void *mem, int len, const char *str) {
+	if (strlen(str) < len)
+		return 1;
+	if (strlen(str) > len)
+		return -1;
+	return memcmp(mem, str, len);
+}
+
 
 
 typedef pthread_mutex_t mutex_t;

daemon/control_ng.c

@@ -2,11 +2,105 @@
 #include "obj.h"
 #include "poller.h"
 #include "bencode.h"
+#include "log.h"
+#include "cookie_cache.h"
 
 
-static void control_ng_incoming(struct obj *obj, char *buf, int len, struct sockaddr_in6 *sin, char *addr) {
+static void control_ng_incoming(struct obj *obj, char *buf, int buf_len, struct sockaddr_in6 *sin, char *addr) {
+	struct control_ng *c = (void *) obj;
+	char *data;
+	bencode_buffer_t bencbuf;
+	bencode_item_t *dict, *resp;
+	char *reply;
+	const char *cmd, *errstr, *cookie;
+	int cmd_len, cookie_len, data_len, reply_len;
+	struct msghdr mh;
+	struct iovec iov[3];
+
+	data = memchr(buf, ' ', buf_len);
+	if (!data || data == buf) {
+		mylog(LOG_WARNING, "Received invalid data on NG port (no cookie) from %s:%u: %.*s", addr, ntohs(sin->sin6_port), buf_len, buf);
+		return;
+	}
+
+	bencode_buffer_init(&bencbuf);
+	resp = bencode_dictionary(&bencbuf);
+
+	cookie = buf;
+	cookie_len = data - buf;
+	*data++ = '\0';
+	data_len = buf_len - cookie_len - 1;
+
+	errstr = "Invalid data (no payload)";
+	if (data_len <= 0)
+		goto err_send;
+
+	reply = cookie_cache_lookup(&c->cookie_cache, cookie);
+	if (reply) {
+		mylog(LOG_INFO, "Detected command from %s:%u as a duplicate", addr, ntohs(sin->sin6_port));
+		reply_len = strlen(reply);
+		resp = NULL;
+		goto send_only;
+	}
+
+	dict = bencode_decode_expect(&bencbuf, data, data_len, BENCODE_DICTIONARY);
+	errstr = "Could not decode dictionary";
+	if (!dict)
+		goto err_send;
+
+	cmd = bencode_dictionary_get_string(dict, "command", &cmd_len);
+	errstr = "Dictionary contains no key \"command\"";
+	if (!cmd)
+		goto err_send;
+
+	mylog(LOG_INFO, "Got valid command from %s:%u: %.*s [%.*s]", addr, ntohs(sin->sin6_port), cmd_len, cmd, data_len, data);
+
+	if (!strmemcmp(cmd, cmd_len, "ping"))
+		bencode_dictionary_add_string(resp, "result", "pong");
+	else {
+		errstr = "Unrecognized command";
+		goto err_send;
+	}
+
+	goto send_out;
+
+err_send:
+	mylog(LOG_WARNING, "Protocol error in packet from %s:%u: %s [%.*s]", addr, ntohs(sin->sin6_port), errstr, data_len, data);
+	bencode_dictionary_add_string(resp, "result", "error");
+	bencode_dictionary_add_string(resp, "error-reason", errstr);
+	goto send_out;
+
+send_out:
+	reply = bencode_collapse(resp, &reply_len);
+
+send_only:
+	ZERO(mh);
+	mh.msg_name = sin;
+	mh.msg_namelen = sizeof(*sin);
+	mh.msg_iov = iov;
+	mh.msg_iovlen = 3;
+
+	iov[0].iov_base = (void *) cookie;
+	iov[0].iov_len = cookie_len;
+	iov[1].iov_base = " ";
+	iov[1].iov_len = 1;
+	iov[2].iov_base = reply;
+	iov[2].iov_len = reply_len;
+
+	sendmsg(c->udp_listener.fd, &mh, 0);
+
+	if (resp)
+		cookie_cache_insert(&c->cookie_cache, cookie, reply, reply_len);
+
+	goto out;
+
+	cookie_cache_remove(&c->cookie_cache, cookie);
+out:
+	bencode_buffer_free(&bencbuf);
 }
 
+
+
 struct control_ng *control_ng_new(struct poller *p, struct in6_addr ip, u_int16_t port, struct callmaster *m) {
 	struct control_ng *c;