From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751716AbeAEDzQ (ORCPT + 1 other); Thu, 4 Jan 2018 22:55:16 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57946 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751662AbeAEDzN (ORCPT ); Thu, 4 Jan 2018 22:55:13 -0500 From: Jason Wang To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: mst@redhat.com, willemb@google.com, Jason Wang Subject: [PATCH net-next V2 2/2] tun: allow to attach ebpf socket filter Date: Fri, 5 Jan 2018 11:54:48 +0800 Message-Id: <1515124488-396-3-git-send-email-jasowang@redhat.com> In-Reply-To: <1515124488-396-1-git-send-email-jasowang@redhat.com> References: <1515124488-396-1-git-send-email-jasowang@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 05 Jan 2018 03:55:13 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: This patch allows userspace to attach eBPF filter to tun. This will allow to implement VM dataplane filtering in a more efficient way compared to cBPF filter by allowing either qemu or libvirt to attach eBPF filter to tun. Signed-off-by: Jason Wang --- drivers/net/tun.c | 39 +++++++++++++++++++++++++++++++++++---- include/uapi/linux/if_tun.h | 1 + 2 files changed, 36 insertions(+), 4 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 0853829..9fc8b70 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -238,6 +238,12 @@ struct tun_struct { struct tun_pcpu_stats __percpu *pcpu_stats; struct bpf_prog __rcu *xdp_prog; struct tun_prog __rcu *steering_prog; + struct tun_prog __rcu *filter_prog; +}; + +struct veth { + __be16 h_vlan_proto; + __be16 h_vlan_TCI; }; static int tun_napi_receive(struct napi_struct *napi, int budget) @@ -984,12 +990,25 @@ static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb) #endif } +static unsigned int run_ebpf_filter(struct tun_struct *tun, + struct sk_buff *skb, + int len) +{ + struct tun_prog *prog = rcu_dereference(tun->filter_prog); + + if (prog) + len = bpf_prog_run_clear_cb(prog->prog, skb); + + return len; +} + /* Net device start xmit */ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) { struct tun_struct *tun = netdev_priv(dev); int txq = skb->queue_mapping; struct tun_file *tfile; + int len = skb->len; rcu_read_lock(); tfile = rcu_dereference(tun->tfiles[txq]); @@ -1015,6 +1034,16 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) sk_filter(tfile->socket.sk, skb)) goto drop; + len = run_ebpf_filter(tun, skb, len); + + /* Trim extra bytes since we may inster vlan proto & TCI + * in tun_put_user(). + */ + if (skb_vlan_tag_present(skb)) + len -= skb_vlan_tag_present(skb) ? sizeof(struct veth) : 0; + if (len <= 0 || pskb_trim(skb, len)) + goto drop; + if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) goto drop; @@ -1904,10 +1933,7 @@ static ssize_t tun_put_user(struct tun_struct *tun, if (vlan_hlen) { int ret; - struct { - __be16 h_vlan_proto; - __be16 h_vlan_TCI; - } veth; + struct veth veth; veth.h_vlan_proto = skb->vlan_proto; veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb)); @@ -2068,6 +2094,7 @@ static void tun_free_netdev(struct net_device *dev) tun_flow_uninit(tun); security_tun_dev_free_security(tun->security); __tun_set_ebpf(tun, &tun->steering_prog, NULL); + __tun_set_ebpf(tun, &tun->filter_prog, NULL); } static void tun_setup(struct net_device *dev) @@ -2849,6 +2876,10 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, ret = tun_set_ebpf(tun, &tun->steering_prog, argp); break; + case TUNSETFILTEREBPF: + ret = tun_set_ebpf(tun, &tun->filter_prog, argp); + break; + default: ret = -EINVAL; break; diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h index fb38c17..ee432cd 100644 --- a/include/uapi/linux/if_tun.h +++ b/include/uapi/linux/if_tun.h @@ -58,6 +58,7 @@ #define TUNSETVNETBE _IOW('T', 222, int) #define TUNGETVNETBE _IOR('T', 223, int) #define TUNSETSTEERINGEBPF _IOR('T', 224, int) +#define TUNSETFILTEREBPF _IOR('T', 225, int) /* TUNSETIFF ifr flags */ #define IFF_TUN 0x0001 -- 2.7.4