epoll: Generalize epoll_ref to cover things other than sockets

The epoll_ref type includes fields for the IP protocol of a socket, and the
socket fd.  However, we already have a few things in the epoll which aren't
protocol sockets, and we may have more in future.  Rename these fields to
an abstract "fd type" and file descriptor for more generality.

Similarly, rather than using existing IP protocol numbers for the type,
introduce our own number space.  For now these just correspond to the
supported protocols, but we'll expand on that in future.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 29 insertions, 11 deletions

diff --git a/passt.h b/passt.h
index edc4841..2110781 100644
--- a/passt.h
+++ b/passt.h
@@ -42,9 +42,27 @@ union epoll_ref;
 #include "udp.h"
 
 /**
- * union epoll_ref - Breakdown of reference for epoll socket bookkeeping
- * @proto:	IP protocol number
- * @s:		Socket number (implies 2^24-1 limit on number of descriptors)
+ * enum epoll_type - Different types of fds we poll over
+ */
+enum epoll_type {
+	/* Special value to indicate an invalid type */
+	EPOLL_TYPE_NONE = 0,
+	/* Sockets and timerfds for TCP handling */
+	EPOLL_TYPE_TCP,
+	/* UDP sockets */
+	EPOLL_TYPE_UDP,
+	/* IPv4 ICMP sockets */
+	EPOLL_TYPE_ICMP,
+	/* ICMPv6 sockets */
+	EPOLL_TYPE_ICMPV6,
+
+	EPOLL_TYPE_MAX = EPOLL_TYPE_ICMPV6,
+};
+
+/**
+ * union epoll_ref - Breakdown of reference for epoll fd bookkeeping
+ * @type:	Type of fd (tells us what to do with events)
+ * @fd:		File descriptor number (implies < 2^24 total descriptors)
  * @tcp:	TCP-specific reference part
  * @udp:	UDP-specific reference part
  * @icmp:	ICMP-specific reference part
@@ -53,10 +71,10 @@ union epoll_ref;
  */
 union epoll_ref {
 	struct {
-		int32_t		proto:8,
-#define SOCKET_REF_BITS		24
-#define SOCKET_MAX		MAX_FROM_BITS(SOCKET_REF_BITS)
-				s:SOCKET_REF_BITS;
+		enum epoll_type type:8;
+#define FD_REF_BITS		24
+#define FD_REF_MAX		MAX_FROM_BITS(FD_REF_BITS)
+		int32_t		fd:FD_REF_BITS;
 		union {
 			union tcp_epoll_ref tcp;
 			union udp_epoll_ref udp;
@@ -78,10 +96,10 @@ static_assert(sizeof(union epoll_ref) <= sizeof(union epoll_data),
 #define PKT_BUF_BYTES		MAX(TAP_BUF_BYTES, 0)
 extern char pkt_buf		[PKT_BUF_BYTES];
 
-extern char *ip_proto_str[];
-#define IP_PROTO_STR(n)							\
-	(((uint8_t)(n) <= IPPROTO_SCTP && ip_proto_str[(n)]) ?		\
-			  ip_proto_str[(n)] : "?")
+extern char *epoll_type_str[];
+#define EPOLL_TYPE_STR(n)						\
+	(((uint8_t)(n) <= EPOLL_TYPE_MAX && epoll_type_str[(n)]) ?	\
+	                                    epoll_type_str[(n)] : "?")
 
 #include <resolv.h>	/* For MAXNS below */