start merging common and docs #76

src/common.c

@@ -333,3 +333,18 @@ errx(int eval, const char *fmt, ...)
 }
 #endif
 
+
+int recent_seqno(int ourseqno, int gotseqno)
+/* Return 1 if we've seen gotseqno recently (current or up to 3 back).
+   Return 0 if gotseqno is new (or very old).
+*/
+{
+	int i;
+	for (i = 0; i < 4; i++, ourseqno--) {
+		if (ourseqno < 0)
+			ourseqno = 7;
+		if (gotseqno == ourseqno)
+			return 1;
+	}
+	return 0;
+}