Whit this patch, the netmap backend supports TSO/UFO/CSUM
offloadings, and accepts the virtio-net header, similarly to what
happens with TAP. The offloading callbacks in the NetClientInfo
interface have been implemented.
Signed-off-by: Vincenzo Maffione <v.maffi...@gmail.com>
---
net/netmap.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 63 insertions(+), 1 deletion(-)
diff --git a/net/netmap.c b/net/netmap.c
index 0ccc497..f02a574 100644
--- a/net/netmap.c
+++ b/net/netmap.c
@@ -54,6 +54,7 @@ typedef struct NetmapState {
bool read_poll;
bool write_poll;
struct iovec iov[IOV_MAX];
+ int vnet_hdr_len; /* Current virtio-net header length. */
} NetmapState;
#define D(format, ...) \
@@ -274,7 +275,7 @@ static ssize_t netmap_receive_iov(NetClientState *nc,
return iov_size(iov, iovcnt);
}
- i = ring->cur;
+ last = i = ring->cur;
avail = ring->avail;
if (avail < iovcnt) {
@@ -394,6 +395,60 @@ static void netmap_cleanup(NetClientState *nc)
s->me.fd = -1;
}
+/* Offloading manipulation support callbacks.
+ *
+ * Currently we are simply able to pass the virtio-net header
+ * throughout the VALE switch, without modifying it or interpreting it.
+ * For this reason we are always able to support TSO/UFO/CSUM and
+ * different header lengths as long as two virtio-net-header-capable
+ * VMs are attached to the bridge.
+ */
+static bool netmap_has_ufo(NetClientState *nc)
+{
+ return true;
+}
+
+static int netmap_has_vnet_hdr(NetClientState *nc)
+{
+ return true;
+}
+
+static int netmap_has_vnet_hdr_len(NetClientState *nc, int len)
+{
+ return len >= 0 && len <= NETMAP_BDG_MAX_OFFSET;
+}
+
+static void netmap_using_vnet_hdr(NetClientState *nc, bool enable)
+{
+}
+
+static void netmap_set_offload(NetClientState *nc, int csum, int tso4, int
tso6,
+ int ecn, int ufo)
+{
+}
+
+static void netmap_set_vnet_hdr_len(NetClientState *nc, int len)
+{
+ NetmapState *s = DO_UPCAST(NetmapState, nc, nc);
+ int err;
+ struct nmreq req;
+
+ /* Issue a NETMAP_BDG_OFFSET command to change the netmap adapter
+ offset of 'me->ifname'. */
+ memset(&req, 0, sizeof(req));
+ pstrcpy(req.nr_name, sizeof(req.nr_name), s->me.ifname);
+ req.nr_version = NETMAP_API;
+ req.nr_cmd = NETMAP_BDG_OFFSET;
+ req.nr_arg1 = len;
+ err = ioctl(s->me.fd, NIOCREGIF, &req);
+ if (err) {
+ error_report("Unable to execute NETMAP_BDG_OFFSET on %s: %s",
+ s->me.ifname, strerror(errno));
+ } else {
+ /* Keep track of the current length, may be usefule in the future. */
+ s->vnet_hdr_len = len;
+ }
+}
/* NetClientInfo methods */
static NetClientInfo net_netmap_info = {
@@ -403,6 +458,12 @@ static NetClientInfo net_netmap_info = {
.receive_iov = netmap_receive_iov,
.poll = netmap_poll,
.cleanup = netmap_cleanup,
+ .has_ufo = netmap_has_ufo,
+ .has_vnet_hdr = netmap_has_vnet_hdr,
+ .has_vnet_hdr_len = netmap_has_vnet_hdr_len,
+ .using_vnet_hdr = netmap_using_vnet_hdr,
+ .set_offload = netmap_set_offload,
+ .set_vnet_hdr_len = netmap_set_vnet_hdr_len,
};
/* The exported init function
@@ -428,6 +489,7 @@ int net_init_netmap(const NetClientOptions *opts,
nc = qemu_new_net_client(&net_netmap_info, peer, "netmap", name);
s = DO_UPCAST(NetmapState, nc, nc);
s->me = me;
+ s->vnet_hdr_len = 0;
netmap_read_poll(s, true); /* Initially only poll for reads. */
return 0;
--
1.8.5.1
