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Date: Tue, 02 Feb 2016 15:57:23 +0100
From: Paolo Abeni <pabeni@...hat.com>
To: Jiri Benc <jbenc@...hat.com>
Cc: netdev@...r.kernel.org
Subject: Re: [PATCH net-next 5/5] vxlan: consolidate vxlan_xmit_skb and
vxlan6_xmit_skb
On Tue, 2016-02-02 at 11:13 +0100, Jiri Benc wrote:
> There's a lot of code duplication. Factor out the duplicate code to a new
> function shared between IPv4 and IPv6 xmit path.
>
> Signed-off-by: Jiri Benc <jbenc@...hat.com>
> ---
> drivers/net/vxlan.c | 141 +++++++++++-----------------------------------------
> 1 file changed, 29 insertions(+), 112 deletions(-)
>
> diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
> index d0f7723fd776..cf7de95eccfc 100644
> --- a/drivers/net/vxlan.c
> +++ b/drivers/net/vxlan.c
> @@ -1684,98 +1684,9 @@ static void vxlan_build_gbp_hdr(struct vxlanhdr *vxh, u32 vxflags,
> gbp->policy_id = htons(md->gbp & VXLAN_GBP_ID_MASK);
> }
>
> -#if IS_ENABLED(CONFIG_IPV6)
> -static int vxlan6_xmit_skb(struct dst_entry *dst, struct sock *sk,
> - struct sk_buff *skb,
> - struct net_device *dev, struct in6_addr *saddr,
> - struct in6_addr *daddr, __u8 prio, __u8 ttl,
> - __be16 src_port, __be16 dst_port, __be32 vni,
> - struct vxlan_metadata *md, bool xnet, u32 vxflags)
> -{
> - struct vxlanhdr *vxh;
> - int min_headroom;
> - int err;
> - bool udp_sum = !(vxflags & VXLAN_F_UDP_ZERO_CSUM6_TX);
> - int type = udp_sum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
> - u16 hdrlen = sizeof(struct vxlanhdr);
> -
> - if ((vxflags & VXLAN_F_REMCSUM_TX) &&
> - skb->ip_summed == CHECKSUM_PARTIAL) {
> - int csum_start = skb_checksum_start_offset(skb);
> -
> - if (csum_start <= VXLAN_MAX_REMCSUM_START &&
> - !(csum_start & VXLAN_RCO_SHIFT_MASK) &&
> - (skb->csum_offset == offsetof(struct udphdr, check) ||
> - skb->csum_offset == offsetof(struct tcphdr, check))) {
> - udp_sum = false;
> - type |= SKB_GSO_TUNNEL_REMCSUM;
> - }
> - }
> -
> - skb_scrub_packet(skb, xnet);
> -
> - min_headroom = LL_RESERVED_SPACE(dst->dev) + dst->header_len
> - + VXLAN_HLEN + sizeof(struct ipv6hdr)
> - + (skb_vlan_tag_present(skb) ? VLAN_HLEN : 0);
> -
> - /* Need space for new headers (invalidates iph ptr) */
> - err = skb_cow_head(skb, min_headroom);
> - if (unlikely(err)) {
> - kfree_skb(skb);
> - goto err;
> - }
> -
> - skb = vlan_hwaccel_push_inside(skb);
> - if (WARN_ON(!skb)) {
> - err = -ENOMEM;
> - goto err;
> - }
> -
> - skb = iptunnel_handle_offloads(skb, udp_sum, type);
> - if (IS_ERR(skb)) {
> - err = -EINVAL;
> - goto err;
> - }
> -
> - vxh = (struct vxlanhdr *) __skb_push(skb, sizeof(*vxh));
> - vxh->vx_flags = htonl(VXLAN_HF_VNI);
> - vxh->vx_vni = vni;
> -
> - if (type & SKB_GSO_TUNNEL_REMCSUM) {
> - u32 data = (skb_checksum_start_offset(skb) - hdrlen) >>
> - VXLAN_RCO_SHIFT;
> -
> - if (skb->csum_offset == offsetof(struct udphdr, check))
> - data |= VXLAN_RCO_UDP;
> -
> - vxh->vx_vni |= htonl(data);
> - vxh->vx_flags |= htonl(VXLAN_HF_RCO);
> -
> - if (!skb_is_gso(skb)) {
> - skb->ip_summed = CHECKSUM_NONE;
> - skb->encapsulation = 0;
> - }
> - }
> -
> - if (vxflags & VXLAN_F_GBP)
> - vxlan_build_gbp_hdr(vxh, vxflags, md);
> -
> - skb_set_inner_protocol(skb, htons(ETH_P_TEB));
> -
> - udp_tunnel6_xmit_skb(dst, sk, skb, dev, saddr, daddr, prio,
> - ttl, src_port, dst_port,
> - !!(vxflags & VXLAN_F_UDP_ZERO_CSUM6_TX));
> - return 0;
> -err:
> - dst_release(dst);
> - return err;
> -}
> -#endif
> -
> -static int vxlan_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
> - __be32 src, __be32 dst, __u8 tos, __u8 ttl, __be16 df,
> - __be16 src_port, __be16 dst_port, __be32 vni,
> - struct vxlan_metadata *md, bool xnet, u32 vxflags)
> +static int vxlan_build_skb(struct sk_buff *skb, struct dst_entry *dst,
> + int iphdr_len, __be32 vni,
> + struct vxlan_metadata *md, u32 vxflags)
> {
> struct vxlanhdr *vxh;
> int min_headroom;
> @@ -1797,8 +1708,8 @@ static int vxlan_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *sk
> }
> }
>
> - min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
> - + VXLAN_HLEN + sizeof(struct iphdr)
> + min_headroom = LL_RESERVED_SPACE(dst->dev) + dst->header_len
> + + VXLAN_HLEN + iphdr_len
> + (skb_vlan_tag_present(skb) ? VLAN_HLEN : 0);
>
> /* Need space for new headers (invalidates iph ptr) */
> @@ -1840,10 +1751,6 @@ static int vxlan_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *sk
> vxlan_build_gbp_hdr(vxh, vxflags, md);
>
> skb_set_inner_protocol(skb, htons(ETH_P_TEB));
> -
> - udp_tunnel_xmit_skb(rt, sk, skb, src, dst, tos, ttl, df,
> - src_port, dst_port, xnet,
> - !(vxflags & VXLAN_F_UDP_CSUM));
> return 0;
> }
>
> @@ -1959,6 +1866,7 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
> __u8 tos, ttl;
> int err;
> u32 flags = vxlan->flags;
> + bool xnet = !net_eq(vxlan->net, dev_net(vxlan->dev));
>
> info = skb_tunnel_info(skb);
>
> @@ -2065,16 +1973,15 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
>
> tos = ip_tunnel_ecn_encap(tos, old_iph, skb);
> ttl = ttl ? : ip4_dst_hoplimit(&rt->dst);
> - err = vxlan_xmit_skb(rt, sk, skb, saddr,
> - dst->sin.sin_addr.s_addr, tos, ttl, df,
> - src_port, dst_port, htonl(vni << 8), md,
> - !net_eq(vxlan->net, dev_net(vxlan->dev)),
> - flags);
> - if (err < 0) {
> - /* skb is already freed. */
> - skb = NULL;
> - goto rt_tx_error;
> - }
> + err = vxlan_build_skb(skb, &rt->dst, sizeof(struct iphdr),
> + htonl(vni << 8), md, flags);
> + if (err < 0)
> + goto xmit_tx_error;
> +
> + udp_tunnel_xmit_skb(rt, sk, skb, saddr,
> + dst->sin.sin_addr.s_addr, tos, ttl, df,
> + src_port, dst_port, xnet,
> + !(flags & VXLAN_F_UDP_CSUM));
> #if IS_ENABLED(CONFIG_IPV6)
> } else {
> struct dst_entry *ndst;
> @@ -2127,10 +2034,17 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
> }
>
> ttl = ttl ? : ip6_dst_hoplimit(ndst);
> - err = vxlan6_xmit_skb(ndst, sk, skb, dev, &saddr, &dst->sin6.sin6_addr,
> - 0, ttl, src_port, dst_port, htonl(vni << 8), md,
> - !net_eq(vxlan->net, dev_net(vxlan->dev)),
> - flags);
> + skb_scrub_packet(skb, xnet);
> + err = vxlan_build_skb(skb, ndst, sizeof(struct ipv6hdr),
> + htonl(vni << 8), md, flags);
I think there is an issue here: in vxlan_build_skb(), 'flags' will be
always tested against VXLAN_F_UDP_CSUM, but when tunneling over ipv6 we
should check VXLAN_F_UDP_ZERO_CSUM6_TX instead.
Probably an explicit 'udp_sum' argument should be added to
vxlan_build_skb().
Paolo
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