net: psample: Add tunnel support

Currently, psample can only send the packet bits after decapsulation.
The tunnel information is lost. Add the tunnel support.

If the sampled packet has no tunnel info, the behavior is the same as
before. If it has, add a nested metadata field named PSAMPLE_ATTR_TUNNEL
and include the tunnel subfields if applicable.

Increase the metadata length for sampled packet with the tunnel info.
If new subfields of tunnel info should be included, update the metadata
length accordingly.

Signed-off-by: Chris Mi <chrism@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 157 insertions, 0 deletions

diff --git a/net/psample/psample.c b/net/psample/psample.c
index 6f2fbc6b9eb2..34a74043840b 100644
--- a/net/psample/psample.c
+++ b/net/psample/psample.c
@@ -14,6 +14,8 @@
 #include <net/genetlink.h>
 #include <net/psample.h>
 #include <linux/spinlock.h>
+#include <net/ip_tunnels.h>
+#include <net/dst_metadata.h>
 
 #define PSAMPLE_MAX_PACKET_SIZE 0xffff
 
@@ -207,10 +209,155 @@ void psample_group_put(struct psample_group *group)
 }
 EXPORT_SYMBOL_GPL(psample_group_put);
 
+static int __psample_ip_tun_to_nlattr(struct sk_buff *skb,
+			      struct ip_tunnel_info *tun_info)
+{
+	unsigned short tun_proto = ip_tunnel_info_af(tun_info);
+	const void *tun_opts = ip_tunnel_info_opts(tun_info);
+	const struct ip_tunnel_key *tun_key = &tun_info->key;
+	int tun_opts_len = tun_info->options_len;
+
+	if (tun_key->tun_flags & TUNNEL_KEY &&
+	    nla_put_be64(skb, PSAMPLE_TUNNEL_KEY_ATTR_ID, tun_key->tun_id,
+			 PSAMPLE_TUNNEL_KEY_ATTR_PAD))
+		return -EMSGSIZE;
+
+	if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE &&
+	    nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE))
+		return -EMSGSIZE;
+
+	switch (tun_proto) {
+	case AF_INET:
+		if (tun_key->u.ipv4.src &&
+		    nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_SRC,
+				    tun_key->u.ipv4.src))
+			return -EMSGSIZE;
+		if (tun_key->u.ipv4.dst &&
+		    nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_DST,
+				    tun_key->u.ipv4.dst))
+			return -EMSGSIZE;
+		break;
+	case AF_INET6:
+		if (!ipv6_addr_any(&tun_key->u.ipv6.src) &&
+		    nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_SRC,
+				     &tun_key->u.ipv6.src))
+			return -EMSGSIZE;
+		if (!ipv6_addr_any(&tun_key->u.ipv6.dst) &&
+		    nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_DST,
+				     &tun_key->u.ipv6.dst))
+			return -EMSGSIZE;
+		break;
+	}
+	if (tun_key->tos &&
+	    nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TOS, tun_key->tos))
+		return -EMSGSIZE;
+	if (nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TTL, tun_key->ttl))
+		return -EMSGSIZE;
+	if ((tun_key->tun_flags & TUNNEL_DONT_FRAGMENT) &&
+	    nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_DONT_FRAGMENT))
+		return -EMSGSIZE;
+	if ((tun_key->tun_flags & TUNNEL_CSUM) &&
+	    nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_CSUM))
+		return -EMSGSIZE;
+	if (tun_key->tp_src &&
+	    nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_SRC, tun_key->tp_src))
+		return -EMSGSIZE;
+	if (tun_key->tp_dst &&
+	    nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_DST, tun_key->tp_dst))
+		return -EMSGSIZE;
+	if ((tun_key->tun_flags & TUNNEL_OAM) &&
+	    nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_OAM))
+		return -EMSGSIZE;
+	if (tun_opts_len) {
+		if (tun_key->tun_flags & TUNNEL_GENEVE_OPT &&
+		    nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_GENEVE_OPTS,
+			    tun_opts_len, tun_opts))
+			return -EMSGSIZE;
+		else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT &&
+			 nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_ERSPAN_OPTS,
+				 tun_opts_len, tun_opts))
+			return -EMSGSIZE;
+	}
+
+	return 0;
+}
+
+static int psample_ip_tun_to_nlattr(struct sk_buff *skb,
+			    struct ip_tunnel_info *tun_info)
+{
+	struct nlattr *nla;
+	int err;
+
+	nla = nla_nest_start_noflag(skb, PSAMPLE_ATTR_TUNNEL);
+	if (!nla)
+		return -EMSGSIZE;
+
+	err = __psample_ip_tun_to_nlattr(skb, tun_info);
+	if (err) {
+		nla_nest_cancel(skb, nla);
+		return err;
+	}
+
+	nla_nest_end(skb, nla);
+
+	return 0;
+}
+
+static int psample_tunnel_meta_len(struct ip_tunnel_info *tun_info)
+{
+	unsigned short tun_proto = ip_tunnel_info_af(tun_info);
+	const struct ip_tunnel_key *tun_key = &tun_info->key;
+	int tun_opts_len = tun_info->options_len;
+	int sum = 0;
+
+	if (tun_key->tun_flags & TUNNEL_KEY)
+		sum += nla_total_size(sizeof(u64));
+
+	if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE)
+		sum += nla_total_size(0);
+
+	switch (tun_proto) {
+	case AF_INET:
+		if (tun_key->u.ipv4.src)
+			sum += nla_total_size(sizeof(u32));
+		if (tun_key->u.ipv4.dst)
+			sum += nla_total_size(sizeof(u32));
+		break;
+	case AF_INET6:
+		if (!ipv6_addr_any(&tun_key->u.ipv6.src))
+			sum += nla_total_size(sizeof(struct in6_addr));
+		if (!ipv6_addr_any(&tun_key->u.ipv6.dst))
+			sum += nla_total_size(sizeof(struct in6_addr));
+		break;
+	}
+	if (tun_key->tos)
+		sum += nla_total_size(sizeof(u8));
+	sum += nla_total_size(sizeof(u8));	/* TTL */
+	if (tun_key->tun_flags & TUNNEL_DONT_FRAGMENT)
+		sum += nla_total_size(0);
+	if (tun_key->tun_flags & TUNNEL_CSUM)
+		sum += nla_total_size(0);
+	if (tun_key->tp_src)
+		sum += nla_total_size(sizeof(u16));
+	if (tun_key->tp_dst)
+		sum += nla_total_size(sizeof(u16));
+	if (tun_key->tun_flags & TUNNEL_OAM)
+		sum += nla_total_size(0);
+	if (tun_opts_len) {
+		if (tun_key->tun_flags & TUNNEL_GENEVE_OPT)
+			sum += nla_total_size(tun_opts_len);
+		else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT)
+			sum += nla_total_size(tun_opts_len);
+	}
+
+	return sum;
+}
+
 void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
 			   u32 trunc_size, int in_ifindex, int out_ifindex,
 			   u32 sample_rate)
 {
+	struct ip_tunnel_info *tun_info;
 	struct sk_buff *nl_skb;
 	int data_len;
 	int meta_len;
@@ -224,6 +371,10 @@ void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
 		   nla_total_size(sizeof(u32)) +	/* group_num */
 		   nla_total_size(sizeof(u32));		/* seq */
 
+	tun_info = skb_tunnel_info(skb);
+	if (tun_info)
+		meta_len += psample_tunnel_meta_len(tun_info);
+
 	data_len = min(skb->len, trunc_size);
 	if (meta_len + nla_total_size(data_len) > PSAMPLE_MAX_PACKET_SIZE)
 		data_len = PSAMPLE_MAX_PACKET_SIZE - meta_len - NLA_HDRLEN
@@ -278,6 +429,12 @@ void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
 			goto error;
 	}
 
+	if (tun_info) {
+		ret = psample_ip_tun_to_nlattr(nl_skb, tun_info);
+		if (unlikely(ret < 0))
+			goto error;
+	}
+
 	genlmsg_end(nl_skb, data);
 	genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0,
 				PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC);