vhost-user: add vhost-user

add virtio and vhost-user functions to connect with QEMU.

  $ ./passt --vhost-user

and

  # qemu-system-x86_64 ... -m 4G \
        -object memory-backend-memfd,id=memfd0,share=on,size=4G \
        -numa node,memdev=memfd0 \
        -chardev socket,id=chr0,path=/tmp/passt_1.socket \
        -netdev vhost-user,id=netdev0,chardev=chr0 \
        -device virtio-net,mac=9a:2b:2c:2d:2e:2f,netdev=netdev0 \
        ...

Signed-off-by: Laurent Vivier <lvivier@redhat.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/udp.c b/udp.c
index de5313d..8c8f7c3 100644
--- a/udp.c
+++ b/udp.c
@@ -681,9 +681,12 @@ static size_t udp_update_hdr6(const struct ctx *c, struct ipv6hdr *ip6h,
 	uh->dest = htons(dstport);
 	uh->len = ip6h->payload_len;
 	uh->check = 0;
-	uh->check = csum(uh, payload_len,
-			 proto_ipv6_header_psum(payload_len, IPPROTO_UDP,
-						src, dst));
+	if (c->mode != MODE_VU || *c->pcap)
+		uh->check = csum(uh, payload_len,
+				 proto_ipv6_header_psum(payload_len, IPPROTO_UDP,
+							src, dst));
+	else
+		uh->check = 0xffff; /* zero checksum is invalid with IPv6 */
 
 	return ip_len;
 }