tap: Implement tap_send() "slow path" in terms of fast path

Most times we send frames to the guest it goes via tap_send_frames().
However "slow path" protocols - ARP, ICMP, ICMPv6, DHCP and DHCPv6 - go
via tap_send().

As well as being a semantic duplication, tap_send() contains at least one
serious problem: it doesn't properly handle short sends, which can be fatal
on the qemu socket connection, since frame boundaries will get out of sync.

Rewrite tap_send() to call tap_send_frames().  While we're there, rename it
tap_send_single() for clarity.

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

1 files changed, 1 insertions, 3 deletions

diff --git a/arp.c b/arp.c
index a35c1b6..113cda2 100644
--- a/arp.c
+++ b/arp.c
@@ -44,7 +44,6 @@ int arp(const struct ctx *c, const struct pool *p)
 	struct arphdr *ah;
 	struct arpmsg *am;
 	size_t len;
-	int ret;
 
 	eh = packet_get(p, 0, 0,			 sizeof(*eh), NULL);
 	ah = packet_get(p, 0, sizeof(*eh),		 sizeof(*ah), NULL);
@@ -83,8 +82,7 @@ int arp(const struct ctx *c, const struct pool *p)
 	memcpy(eh->h_dest,	eh->h_source,	sizeof(eh->h_dest));
 	memcpy(eh->h_source,	c->mac,		sizeof(eh->h_source));
 
-	if ((ret = tap_send(c, eh, len)) < 0)
-		warn("ARP: send: %s", strerror(ret));
+	tap_send_single(c, eh, len);
 
 	return 1;
 }