From 1a66a836da630cd70f3639208da549b549ce576b Mon Sep 17 00:00:00 2001 From: William Tu Date: Fri, 25 Aug 2017 09:21:28 -0700 Subject: [PATCH] gre: add collect_md mode to ERSPAN tunnel Similar to gre, vxlan, geneve, ipip tunnels, allow ERSPAN tunnels to operate in 'collect metadata' mode. bpf_skb_[gs]et_tunnel_key() helpers can make use of it right away. OVS can use it as well in the future. Signed-off-by: William Tu Signed-off-by: David S. Miller --- include/net/ip_tunnels.h | 4 +- net/ipv4/ip_gre.c | 102 +++++++++++++++++++++++++++++++++++++-- 2 files changed, 101 insertions(+), 5 deletions(-) diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h index 625c29329372..992652856fe8 100644 --- a/include/net/ip_tunnels.h +++ b/include/net/ip_tunnels.h @@ -154,8 +154,10 @@ struct ip_tunnel { #define TUNNEL_GENEVE_OPT __cpu_to_be16(0x0800) #define TUNNEL_VXLAN_OPT __cpu_to_be16(0x1000) #define TUNNEL_NOCACHE __cpu_to_be16(0x2000) +#define TUNNEL_ERSPAN_OPT __cpu_to_be16(0x4000) -#define TUNNEL_OPTIONS_PRESENT (TUNNEL_GENEVE_OPT | TUNNEL_VXLAN_OPT) +#define TUNNEL_OPTIONS_PRESENT \ + (TUNNEL_GENEVE_OPT | TUNNEL_VXLAN_OPT | TUNNEL_ERSPAN_OPT) struct tnl_ptk_info { __be16 flags; diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 453b7925b940..0162fb955b33 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -113,6 +113,8 @@ MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN"); static struct rtnl_link_ops ipgre_link_ops __read_mostly; static int ipgre_tunnel_init(struct net_device *dev); +static void erspan_build_header(struct sk_buff *skb, + __be32 id, u32 index, bool truncate); static unsigned int ipgre_net_id __read_mostly; static unsigned int gre_tap_net_id __read_mostly; @@ -287,7 +289,33 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi, false, false) < 0) goto drop; - tunnel->index = ntohl(index); + if (tunnel->collect_md) { + struct ip_tunnel_info *info; + struct erspan_metadata *md; + __be64 tun_id; + __be16 flags; + + tpi->flags |= TUNNEL_KEY; + flags = tpi->flags; + tun_id = key32_to_tunnel_id(tpi->key); + + tun_dst = ip_tun_rx_dst(skb, flags, + tun_id, sizeof(*md)); + if (!tun_dst) + return PACKET_REJECT; + + md = ip_tunnel_info_opts(&tun_dst->u.tun_info); + if (!md) + return PACKET_REJECT; + + md->index = index; + info = &tun_dst->u.tun_info; + info->key.tun_flags |= TUNNEL_ERSPAN_OPT; + info->options_len = sizeof(*md); + } else { + tunnel->index = ntohl(index); + } + skb_reset_mac_header(skb); ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error); return PACKET_RCVD; @@ -523,6 +551,64 @@ err_free_skb: dev->stats.tx_dropped++; } +static void erspan_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 erspan_metadata *md; + struct rtable *rt = NULL; + bool truncate = false; + struct flowi4 fl; + int tunnel_hlen; + __be16 df; + + tun_info = skb_tunnel_info(skb); + if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) || + ip_tunnel_info_af(tun_info) != AF_INET)) + goto err_free_skb; + + key = &tun_info->key; + + /* ERSPAN has fixed 8 byte GRE header */ + tunnel_hlen = 8 + sizeof(struct erspanhdr); + + rt = prepare_fb_xmit(skb, dev, &fl, tunnel_hlen); + if (!rt) + return; + + if (gre_handle_offloads(skb, false)) + goto err_free_rt; + + if (skb->len > dev->mtu) { + pskb_trim(skb, dev->mtu); + truncate = true; + } + + md = ip_tunnel_info_opts(tun_info); + if (!md) + goto err_free_rt; + + erspan_build_header(skb, tunnel_id_to_key32(key->tun_id), + ntohl(md->index), truncate); + + gre_build_header(skb, 8, TUNNEL_SEQ, + htons(ETH_P_ERSPAN), 0, htonl(tunnel->o_seqno++)); + + df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0; + + iptunnel_xmit(skb->sk, rt, skb, fl.saddr, key->u.ipv4.dst, IPPROTO_GRE, + key->tos, key->ttl, df, false); + return; + +err_free_rt: + ip_rt_put(rt); +err_free_skb: + kfree_skb(skb); + dev->stats.tx_dropped++; +} + static int gre_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb) { struct ip_tunnel_info *info = skb_tunnel_info(skb); @@ -636,6 +722,11 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb, struct ip_tunnel *tunnel = netdev_priv(dev); bool truncate = false; + if (tunnel->collect_md) { + erspan_fb_xmit(skb, dev, skb->protocol); + return NETDEV_TX_OK; + } + if (gre_handle_offloads(skb, false)) goto free_skb; @@ -998,9 +1089,12 @@ static int erspan_validate(struct nlattr *tb[], struct nlattr *data[], return ret; /* ERSPAN should only have GRE sequence and key flag */ - flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]); - flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]); - if (flags != (GRE_SEQ | GRE_KEY)) + if (data[IFLA_GRE_OFLAGS]) + flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]); + if (data[IFLA_GRE_IFLAGS]) + flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]); + if (!data[IFLA_GRE_COLLECT_METADATA] && + flags != (GRE_SEQ | GRE_KEY)) return -EINVAL; /* ERSPAN Session ID only has 10-bit. Since we reuse