On 03/01/2018 01:11 AM, William Tu wrote:
> Currently GRE sequence number can only be used in native
> tunnel mode. This patch adds sequence number support for
> gre collect metadata mode. RFC2890 defines GRE sequence
> number to be specific to the traffic flow identified by the
> key. However, this patch does not implement per-key seqno.
> The sequence number is shared in the same tunnel device.
> That is, different tunnel keys using the same collect_md
> tunnel share single sequence number.
>
> Signed-off-by: William Tu <u9012...@gmail.com>
> ---
> include/uapi/linux/bpf.h | 1 +
> net/core/filter.c | 4 +++-
> net/ipv4/ip_gre.c | 7 +++++--
> net/ipv6/ip6_gre.c | 13 ++++++++-----
> 4 files changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index db6bdc375126..2c6dd942953d 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -800,6 +800,7 @@ enum bpf_func_id {
> /* BPF_FUNC_skb_set_tunnel_key flags. */
> #define BPF_F_ZERO_CSUM_TX (1ULL << 1)
> #define BPF_F_DONT_FRAGMENT (1ULL << 2)
> +#define BPF_F_GRE_SEQ (1ULL << 3)
>
> /* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
> * BPF_FUNC_perf_event_read_value flags.
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 0c121adbdbaa..010305e0791a 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -2991,7 +2991,7 @@ BPF_CALL_4(bpf_skb_set_tunnel_key, struct sk_buff *,
> skb,
> struct ip_tunnel_info *info;
>
> if (unlikely(flags & ~(BPF_F_TUNINFO_IPV6 | BPF_F_ZERO_CSUM_TX |
> - BPF_F_DONT_FRAGMENT)))
> + BPF_F_DONT_FRAGMENT | BPF_F_GRE_SEQ)))
> return -EINVAL;
> if (unlikely(size != sizeof(struct bpf_tunnel_key))) {
> switch (size) {
> @@ -3025,6 +3025,8 @@ BPF_CALL_4(bpf_skb_set_tunnel_key, struct sk_buff *,
> skb,
> info->key.tun_flags |= TUNNEL_DONT_FRAGMENT;
> if (flags & BPF_F_ZERO_CSUM_TX)
> info->key.tun_flags &= ~TUNNEL_CSUM;
> + if (flags & BPF_F_GRE_SEQ)
> + info->key.tun_flags |= TUNNEL_SEQ;
Ok, looks fine. My only minor request would be to rename BPF_F_GRE_SEQ
into e.g. BPF_F_SEQ_NUMBER to at least not have something GRE specific
in the name in case we could later on reuse it elsewhere as well, and
the bpf_skb_set_tunnel_key() is unaware of the underlying encap anyway.
> info->key.tun_id = cpu_to_be64(from->tunnel_id);
> info->key.tos = from->tunnel_tos;
> diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
> index 0fe1d69b5df4..95fd225f402e 100644
> --- a/net/ipv4/ip_gre.c
> +++ b/net/ipv4/ip_gre.c
> @@ -522,6 +522,7 @@ static struct rtable *prepare_fb_xmit(struct sk_buff *skb,
> static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
> __be16 proto)
> {
> + struct ip_tunnel *tunnel = netdev_priv(dev);
> struct ip_tunnel_info *tun_info;
> const struct ip_tunnel_key *key;
> struct rtable *rt = NULL;
> @@ -545,9 +546,11 @@ static void gre_fb_xmit(struct sk_buff *skb, struct
> net_device *dev,
> if (gre_handle_offloads(skb, !!(tun_info->key.tun_flags & TUNNEL_CSUM)))
> goto err_free_rt;
>
> - flags = tun_info->key.tun_flags & (TUNNEL_CSUM | TUNNEL_KEY);
> + flags = tun_info->key.tun_flags &
> + (TUNNEL_CSUM | TUNNEL_KEY | TUNNEL_SEQ);
> gre_build_header(skb, tunnel_hlen, flags, proto,
> - tunnel_id_to_key32(tun_info->key.tun_id), 0);
> + tunnel_id_to_key32(tun_info->key.tun_id),
> + (flags | TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0);
>
> df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0;
>
> diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
> index 4f150a394387..16c5dfcbd195 100644
> --- a/net/ipv6/ip6_gre.c
> +++ b/net/ipv6/ip6_gre.c
> @@ -695,9 +695,6 @@ static netdev_tx_t __gre6_xmit(struct sk_buff *skb,
> else
> fl6->daddr = tunnel->parms.raddr;
>
> - if (tunnel->parms.o_flags & TUNNEL_SEQ)
> - tunnel->o_seqno++;
> -
> /* Push GRE header. */
> protocol = (dev->type == ARPHRD_ETHER) ? htons(ETH_P_TEB) : proto;
>
> @@ -720,14 +717,20 @@ static netdev_tx_t __gre6_xmit(struct sk_buff *skb,
> fl6->flowi6_uid = sock_net_uid(dev_net(dev), NULL);
>
> dsfield = key->tos;
> - flags = key->tun_flags & (TUNNEL_CSUM | TUNNEL_KEY);
> + flags = key->tun_flags &
> + (TUNNEL_CSUM | TUNNEL_KEY | TUNNEL_SEQ);
> tunnel->tun_hlen = gre_calc_hlen(flags);
>
> gre_build_header(skb, tunnel->tun_hlen,
> flags, protocol,
> - tunnel_id_to_key32(tun_info->key.tun_id), 0);
> + tunnel_id_to_key32(tun_info->key.tun_id),
> + (flags | TUNNEL_SEQ) ? htonl(tunnel->o_seqno++)
> + : 0);
>
> } else {
> + if (tunnel->parms.o_flags & TUNNEL_SEQ)
> + tunnel->o_seqno++;
> +
> gre_build_header(skb, tunnel->tun_hlen, tunnel->parms.o_flags,
> protocol, tunnel->parms.o_key,
> htonl(tunnel->o_seqno));
>
