[RFC PATCH 6/7] tun: populate hash in virtio-net header when needed
From: Yuri Benditovich <hidden>
Date: 2021-01-12 19:43:53
Also in:
bpf, kvm, lkml, virtualization
Subsystem:
networking drivers, the rest, tun/tap driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Willem de Bruijn, Jason Wang
If the BPF program populated the hash in the skb the tun propagates the hash value and hash report type to the respective fields of virtio-net header. Signed-off-by: Yuri Benditovich <redacted> --- drivers/net/tun.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 45f4f04a4a3e..214feb0b16fb 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c@@ -556,15 +556,20 @@ static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb) { struct tun_prog *prog; u32 numqueues; - u16 ret = 0; + u32 ret = 0; numqueues = READ_ONCE(tun->numqueues); if (!numqueues) return 0; prog = rcu_dereference(tun->steering_prog); - if (prog) + if (prog) { ret = bpf_prog_run_clear_cb(prog->prog, skb); + if (tun->bpf_populates_hash) { + *skb_hash_report_type(skb) = (__u8)(ret >> 16); + ret &= 0xffff; + } + } return ret % numqueues; }
@@ -2062,6 +2067,7 @@ static ssize_t tun_put_user(struct tun_struct *tun, if (vnet_hdr_sz) { struct virtio_net_hdr gso; + __u16 extra_copy = 0; if (iov_iter_count(iter) < vnet_hdr_sz) return -EINVAL;
@@ -2085,7 +2091,20 @@ static ssize_t tun_put_user(struct tun_struct *tun, if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso)) return -EFAULT; - iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso)); + if (tun->bpf_populates_hash && + vnet_hdr_sz >= sizeof(struct virtio_net_hdr_v1_hash)) { + struct virtio_net_hdr_v1_hash hdr; + + hdr.hdr.num_buffers = 0; + hdr.hash_value = cpu_to_le32(skb_get_hash(skb)); + hdr.hash_report = cpu_to_le16(*skb_hash_report_type(skb)); + hdr.padding = 0; + extra_copy = sizeof(hdr) - sizeof(gso); + if (copy_to_iter(&hdr.hdr.num_buffers, extra_copy, iter) != extra_copy) + return -EFAULT; + } + + iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso) - extra_copy); } if (vlan_hlen) {
--
2.17.1