From 105b916361ca6e9e63112444c323cc193303120c Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Tue, 16 Feb 2021 07:25:09 +0100 Subject: passt: New design and implementation with native Layer 4 sockets This is a reimplementation, partially building on the earlier draft, that uses L4 sockets (SOCK_DGRAM, SOCK_STREAM) instead of SOCK_RAW, providing L4-L2 translation functionality without requiring any security capability. Conceptually, this follows the design presented at: https://gitlab.com/abologna/kubevirt-and-kvm/-/blob/master/Networking.md The most significant novelty here comes from TCP and UDP translation layers. In particular, the TCP state and translation logic follows the intent of being minimalistic, without reimplementing a full TCP stack in either direction, and synchronising as much as possible the TCP dynamic and flows between guest and host kernel. Another important introduction concerns addressing, port translation and forwarding. The Layer 4 implementations now attempt to bind on all unbound ports, in order to forward connections in a transparent way. While at it: - the qemu 'tap' back-end can't be used as-is by qrap anymore, because of explicit checks now introduced in qemu to ensure that the corresponding file descriptor is actually a tap device. For this reason, qrap now operates on a 'socket' back-end type, accounting for and building the additional header reporting frame length - provide a demo script that sets up namespaces, addresses and routes, and starts the daemon. A virtual machine started in the network namespace, wrapped by qrap, will now directly interface with passt and communicate using Layer 4 sockets provided by the host kernel. Signed-off-by: Stefano Brivio --- tap.h | 3 +++ 1 file changed, 3 insertions(+) create mode 100644 tap.h (limited to 'tap.h') diff --git a/tap.h b/tap.h new file mode 100644 index 0000000..ecea936 --- /dev/null +++ b/tap.h @@ -0,0 +1,3 @@ +void tap_ip_send(struct ctx *c, struct in6_addr *src, uint8_t proto, + char *in, size_t len); +int tap_send(int fd, void *data, size_t len, int flags); -- cgit v1.2.3