[PATCH 9/9] epoll: Use different epoll types for passt and pasta tap fds

[David Gibson <david@gibson.dropbear.id.au>]

Currently we have a single epoll event type for the "tap" fd, which could
be either a handle on a /dev/net/tun device (pasta) or a connected Unix
socket (passt).  However for the two modes we call different handler
functions.  Simplify this a little by using different epoll types and
dispatching directly to the correct handler function.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 passt.c | 10 +++++++---
 passt.h |  6 ++++--
 tap.c   | 39 +++++++++++++++------------------------
 tap.h   |  5 ++++-
 4 files changed, 30 insertions(+), 30 deletions(-)

diff --git a/passt.c b/passt.c
index c60f346..c297de6 100644
--- a/passt.c
+++ b/passt.c
@@ -63,7 +63,8 @@ char *epoll_type_str[EPOLL_TYPE_MAX+1] = {
 	[EPOLL_TYPE_ICMP]	= "ICMP socket",
 	[EPOLL_TYPE_ICMPV6]	= "ICMPv6 socket",
 	[EPOLL_TYPE_NSQUIT]	= "namespace inotify",
-	[EPOLL_TYPE_TAP]	= "tap device",
+	[EPOLL_TYPE_TAP_PASTA]	= "/dev/net/tun device",
+	[EPOLL_TYPE_TAP_PASST]	= "connected qemu socket",
 	[EPOLL_TYPE_TAP_LISTEN]	= "listening qemu socket",
 };
 
@@ -317,8 +318,11 @@ loop:
 		      EPOLL_TYPE_STR(ref.type), ref.fd, events);
 
 		switch (ref.type) {
-		case EPOLL_TYPE_TAP:
-			tap_handler(&c, events[i].events, &now);
+		case EPOLL_TYPE_TAP_PASTA:
+			tap_handler_pasta(&c, eventmask, &now);
+			break;
+		case EPOLL_TYPE_TAP_PASST:
+			tap_handler_passt(&c, eventmask, &now);
 			break;
 		case EPOLL_TYPE_TAP_LISTEN:
 			tap_listen_handler(&c, eventmask);
diff --git a/passt.h b/passt.h
index 7dae08b..e13cf13 100644
--- a/passt.h
+++ b/passt.h
@@ -61,8 +61,10 @@ enum epoll_type {
 	EPOLL_TYPE_ICMPV6,
 	/* inotify fd watching for end of netns (pasta) */
 	EPOLL_TYPE_NSQUIT,
-	/* tap char device, or connected qemu socket fd */
-	EPOLL_TYPE_TAP,
+	/* tuntap character device */
+	EPOLL_TYPE_TAP_PASTA,
+	/* socket connected to qemu  */
+	EPOLL_TYPE_TAP_PASST,
 	/* socket listening for qemu socket connections */
 	EPOLL_TYPE_TAP_LISTEN,
 
diff --git a/tap.c b/tap.c
index 8468f86..3ce7e0b 100644
--- a/tap.c
+++ b/tap.c
@@ -914,8 +914,8 @@ static void tap_sock_reset(struct ctx *c)
  * @events:	epoll events
  * @now:	Current timestamp
  */
-static void tap_handler_passt(struct ctx *c, uint32_t events,
-			      const struct timespec *now)
+void tap_handler_passt(struct ctx *c, uint32_t events,
+		       const struct timespec *now)
 {
 	struct ethhdr *eh;
 	ssize_t n, rem;
@@ -1001,13 +1001,13 @@ next:
 }
 
 /**
- * tap_handler_pasta() - Packet handler for tuntap file descriptor
+ * tap_handler_pasta() - Packet handler for /dev/net/tun file descriptor
  * @c:		Execution context
  * @events:	epoll events
  * @now:	Current timestamp
  */
-static void tap_handler_pasta(struct ctx *c, uint32_t events,
-			      const struct timespec *now)
+void tap_handler_pasta(struct ctx *c, uint32_t events,
+		       const struct timespec *now)
 {
 	ssize_t n, len;
 	int ret;
@@ -1148,7 +1148,7 @@ static void tap_sock_unix_init(struct ctx *c)
  */
 void tap_listen_handler(struct ctx *c, uint32_t events)
 {
-	union epoll_ref ref = { .type = EPOLL_TYPE_TAP };
+	union epoll_ref ref = { .type = EPOLL_TYPE_TAP_PASST };
 	struct epoll_event ev = { 0 };
 	int v = INT_MAX / 2;
 	struct ucred ucred;
@@ -1230,12 +1230,12 @@ static int tap_ns_tun(void *arg)
 }
 
 /**
- * tap_sock_init_tun() - Set up tuntap file descriptor
+ * tap_sock_tun_init() - Set up /dev/net/tun file descriptor
  * @c:		Execution context
  */
 static void tap_sock_tun_init(struct ctx *c)
 {
-	union epoll_ref ref = { .type = EPOLL_TYPE_TAP };
+	union epoll_ref ref = { .type = EPOLL_TYPE_TAP_PASTA };
 	struct epoll_event ev = { 0 };
 
 	NS_CALL(tap_ns_tun, c);
@@ -1268,11 +1268,16 @@ void tap_sock_init(struct ctx *c)
 	}
 
 	if (c->fd_tap != -1) { /* Passed as --fd */
-		union epoll_ref ref = { .type = EPOLL_TYPE_TAP };
 		struct epoll_event ev = { 0 };
-		ASSERT(c->one_off);
+		union epoll_ref ref;
 
+		ASSERT(c->one_off);
 		ref.fd = c->fd_tap;
+		if (c->mode == MODE_PASST)
+			ref.type = EPOLL_TYPE_TAP_PASST;
+		else
+			ref.type = EPOLL_TYPE_TAP_PASTA;
+
 		ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 		ev.data.u64 = ref.u64;
 		epoll_ctl(c->epollfd, EPOLL_CTL_ADD, c->fd_tap, &ev);
@@ -1286,17 +1291,3 @@ void tap_sock_init(struct ctx *c)
 		tap_sock_tun_init(c);
 	}
 }
-
-/**
- * tap_handler() - Packet handler for AF_UNIX or tuntap file descriptor
- * @c:		Execution context
- * @events:	epoll events
- * @now:	Current timestamp, can be NULL on EPOLLERR
- */
-void tap_handler(struct ctx *c, uint32_t events, const struct timespec *now)
-{
-	if (c->mode == MODE_PASST)
-		tap_handler_passt(c, events, now);
-	else if (c->mode == MODE_PASTA)
-		tap_handler_pasta(c, events, now);
-}
diff --git a/tap.h b/tap.h
index dd6bfdd..021fb7c 100644
--- a/tap.h
+++ b/tap.h
@@ -77,7 +77,10 @@ void tap_send_frames(struct ctx *c, const struct iovec *iov, size_t n);
 void tap_update_mac(struct tap_hdr *taph,
 		    const unsigned char *eth_d, const unsigned char *eth_s);
 void tap_listen_handler(struct ctx *c, uint32_t events);
-void tap_handler(struct ctx *c, uint32_t events, const struct timespec *now);
+void tap_handler_pasta(struct ctx *c, uint32_t events,
+		       const struct timespec *now);
+void tap_handler_passt(struct ctx *c, uint32_t events,
+		       const struct timespec *now);
 void tap_sock_init(struct ctx *c);
 
 #endif /* TAP_H */
-- 
@@ -77,7 +77,10 @@ void tap_send_frames(struct ctx *c, const struct iovec *iov, size_t n);
 void tap_update_mac(struct tap_hdr *taph,
 		    const unsigned char *eth_d, const unsigned char *eth_s);
 void tap_listen_handler(struct ctx *c, uint32_t events);
-void tap_handler(struct ctx *c, uint32_t events, const struct timespec *now);
+void tap_handler_pasta(struct ctx *c, uint32_t events,
+		       const struct timespec *now);
+void tap_handler_passt(struct ctx *c, uint32_t events,
+		       const struct timespec *now);
 void tap_sock_init(struct ctx *c);
 
 #endif /* TAP_H */
-- 
2.41.0