Commit 81bbbb69 authored by Martin KaFai Lau's avatar Martin KaFai Lau
Browse files

Merge branch 'bpf: Add ipip6 and ip6ip decap support for bpf_skb_adjust_room()' 



Ziyang Xuan says:

====================

Add ipip6 and ip6ip decap support for bpf_skb_adjust_room().
Main use case is for using cls_bpf on ingress hook to decapsulate
IPv4 over IPv6 and IPv6 over IPv4 tunnel packets.

And add ipip6 and ip6ip decap testcases to verify that
bpf_skb_adjust_room() correctly decapsulate ipip6 and ip6ip
tunnel packets.

$./test_tc_tunnel.sh
ipip
encap 192.168.1.1 to 192.168.1.2, type ipip, mac none len 100
test basic connectivity
0
test bpf encap without decap (expect failure)
Ncat: TIMEOUT.
1
test bpf encap with tunnel device decap
0
test bpf encap with bpf decap
0
OK
ipip6
encap 192.168.1.1 to 192.168.1.2, type ipip6, mac none len 100
test basic connectivity
0
test bpf encap without decap (expect failure)
Ncat: TIMEOUT.
1
test bpf encap with tunnel device decap
0
test bpf encap with bpf decap
0
OK
ip6ip6
encap fd::1 to fd::2, type ip6tnl, mac none len 100
test basic connectivity
0
test bpf encap without decap (expect failure)
Ncat: TIMEOUT.
1
test bpf encap with tunnel device decap
0
test bpf encap with bpf decap
0
OK
sit
encap fd::1 to fd::2, type sit, mac none len 100
test basic connectivity
0
test bpf encap without decap (expect failure)
Ncat: TIMEOUT.
1
test bpf encap with tunnel device decap
0
test bpf encap with bpf decap
0
OK
...
OK. All tests passed

v3:
  - Fix compilation failure of selftests/bpf.
  - Combine two new branches in bpf_skb_adjust_room().
  - Simplify description for new flags BPF_F_ADJ_ROOM_DECAP_L3_IP*.

v2:
  - Use decap flags to indicate the new IP header.
    Do not rely on skb->encapsulation.
====================

Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
parents 1c48391b 7105f76f

include/uapi/linux/bpf.h

+7 −0
Original line number Diff line number Diff line
@@ -2647,6 +2647,11 @@ union bpf_attr { 
 *		  Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the

 *		  L2 type as Ethernet.

 *

 *		* **BPF_F_ADJ_ROOM_DECAP_L3_IPV4**,

 *		  **BPF_F_ADJ_ROOM_DECAP_L3_IPV6**:

 *		  Indicate the new IP header version after decapsulating the outer

 *		  IP header. Used when the inner and outer IP versions are different.

 *

 * 		A call to this helper is susceptible to change the underlying

 * 		packet buffer. Therefore, at load time, all checks on pointers

 * 		previously done by the verifier are invalidated and must be
@@ -5807,6 +5812,8 @@ enum { 
	BPF_F_ADJ_ROOM_ENCAP_L4_UDP	= (1ULL << 4),

	BPF_F_ADJ_ROOM_NO_CSUM_RESET	= (1ULL << 5),

	BPF_F_ADJ_ROOM_ENCAP_L2_ETH	= (1ULL << 6),

	BPF_F_ADJ_ROOM_DECAP_L3_IPV4	= (1ULL << 7),

	BPF_F_ADJ_ROOM_DECAP_L3_IPV6	= (1ULL << 8),

};



enum {

net/core/filter.c

+30 −1
Original line number Diff line number Diff line
@@ -3381,13 +3381,17 @@ static u32 bpf_skb_net_base_len(const struct sk_buff *skb) 
#define BPF_F_ADJ_ROOM_ENCAP_L3_MASK	(BPF_F_ADJ_ROOM_ENCAP_L3_IPV4 | \

					 BPF_F_ADJ_ROOM_ENCAP_L3_IPV6)



#define BPF_F_ADJ_ROOM_DECAP_L3_MASK	(BPF_F_ADJ_ROOM_DECAP_L3_IPV4 | \

					 BPF_F_ADJ_ROOM_DECAP_L3_IPV6)



#define BPF_F_ADJ_ROOM_MASK		(BPF_F_ADJ_ROOM_FIXED_GSO | \

					 BPF_F_ADJ_ROOM_ENCAP_L3_MASK | \

					 BPF_F_ADJ_ROOM_ENCAP_L4_GRE | \

					 BPF_F_ADJ_ROOM_ENCAP_L4_UDP | \

					 BPF_F_ADJ_ROOM_ENCAP_L2_ETH | \

					 BPF_F_ADJ_ROOM_ENCAP_L2( \

					  BPF_ADJ_ROOM_ENCAP_L2_MASK))

					  BPF_ADJ_ROOM_ENCAP_L2_MASK) | \

					 BPF_F_ADJ_ROOM_DECAP_L3_MASK)



static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff,

			    u64 flags)
@@ -3501,6 +3505,7 @@ static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff, 
	int ret;



	if (unlikely(flags & ~(BPF_F_ADJ_ROOM_FIXED_GSO |

			       BPF_F_ADJ_ROOM_DECAP_L3_MASK |

			       BPF_F_ADJ_ROOM_NO_CSUM_RESET)))

		return -EINVAL;
@@ -3519,6 +3524,14 @@ static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff, 
	if (unlikely(ret < 0))

		return ret;



	/* Match skb->protocol to new outer l3 protocol */

	if (skb->protocol == htons(ETH_P_IP) &&

	    flags & BPF_F_ADJ_ROOM_DECAP_L3_IPV6)

		skb->protocol = htons(ETH_P_IPV6);

	else if (skb->protocol == htons(ETH_P_IPV6) &&

		 flags & BPF_F_ADJ_ROOM_DECAP_L3_IPV4)

		skb->protocol = htons(ETH_P_IP);



	if (skb_is_gso(skb)) {

		struct skb_shared_info *shinfo = skb_shinfo(skb);
@@ -3608,6 +3621,22 @@ BPF_CALL_4(bpf_skb_adjust_room, struct sk_buff *, skb, s32, len_diff, 
		return -ENOTSUPP;

	}



	if (flags & BPF_F_ADJ_ROOM_DECAP_L3_MASK) {

		if (!shrink)

			return -EINVAL;



		switch (flags & BPF_F_ADJ_ROOM_DECAP_L3_MASK) {

		case BPF_F_ADJ_ROOM_DECAP_L3_IPV4:

			len_min = sizeof(struct iphdr);

			break;

		case BPF_F_ADJ_ROOM_DECAP_L3_IPV6:

			len_min = sizeof(struct ipv6hdr);

			break;

		default:

			return -EINVAL;

		}

	}



	len_cur = skb->len - skb_network_offset(skb);

	if ((shrink && (len_diff_abs >= len_cur ||

			len_cur - len_diff_abs < len_min)) ||

tools/include/uapi/linux/bpf.h

+7 −0
Original line number Diff line number Diff line
@@ -2647,6 +2647,11 @@ union bpf_attr { 
 *		  Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the

 *		  L2 type as Ethernet.

 *

 *		* **BPF_F_ADJ_ROOM_DECAP_L3_IPV4**,

 *		  **BPF_F_ADJ_ROOM_DECAP_L3_IPV6**:

 *		  Indicate the new IP header version after decapsulating the outer

 *		  IP header. Used when the inner and outer IP versions are different.

 *

 * 		A call to this helper is susceptible to change the underlying

 * 		packet buffer. Therefore, at load time, all checks on pointers

 * 		previously done by the verifier are invalidated and must be
@@ -5807,6 +5812,8 @@ enum { 
	BPF_F_ADJ_ROOM_ENCAP_L4_UDP	= (1ULL << 4),

	BPF_F_ADJ_ROOM_NO_CSUM_RESET	= (1ULL << 5),

	BPF_F_ADJ_ROOM_ENCAP_L2_ETH	= (1ULL << 6),

	BPF_F_ADJ_ROOM_DECAP_L3_IPV4    = (1ULL << 7),

	BPF_F_ADJ_ROOM_DECAP_L3_IPV6    = (1ULL << 8),

};



enum {

tools/testing/selftests/bpf/progs/test_tc_tunnel.c

+89 −2
Original line number Diff line number Diff line
@@ -38,6 +38,10 @@ static const int cfg_udp_src = 20000; 
#define	VXLAN_FLAGS     0x8

#define	VXLAN_VNI       1



#ifndef NEXTHDR_DEST

#define NEXTHDR_DEST	60

#endif



/* MPLS label 1000 with S bit (last label) set and ttl of 255. */

static const __u32 mpls_label = __bpf_constant_htonl(1000 << 12 |

						     MPLS_LS_S_MASK | 0xff);
@@ -363,6 +367,61 @@ static __always_inline int __encap_ipv6(struct __sk_buff *skb, __u8 encap_proto, 
	return TC_ACT_OK;

}



static int encap_ipv6_ipip6(struct __sk_buff *skb)

{

	struct iphdr iph_inner;

	struct v6hdr h_outer;

	struct tcphdr tcph;

	struct ethhdr eth;

	__u64 flags;

	int olen;



	if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,

			       sizeof(iph_inner)) < 0)

		return TC_ACT_OK;



	/* filter only packets we want */

	if (bpf_skb_load_bytes(skb, ETH_HLEN + (iph_inner.ihl << 2),

			       &tcph, sizeof(tcph)) < 0)

		return TC_ACT_OK;



	if (tcph.dest != __bpf_constant_htons(cfg_port))

		return TC_ACT_OK;



	olen = sizeof(h_outer.ip);



	flags = BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_ENCAP_L3_IPV6;



	/* add room between mac and network header */

	if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, flags))

		return TC_ACT_SHOT;



	/* prepare new outer network header */

	memset(&h_outer.ip, 0, sizeof(h_outer.ip));

	h_outer.ip.version = 6;

	h_outer.ip.hop_limit = iph_inner.ttl;

	h_outer.ip.saddr.s6_addr[1] = 0xfd;

	h_outer.ip.saddr.s6_addr[15] = 1;

	h_outer.ip.daddr.s6_addr[1] = 0xfd;

	h_outer.ip.daddr.s6_addr[15] = 2;

	h_outer.ip.payload_len = iph_inner.tot_len;

	h_outer.ip.nexthdr = IPPROTO_IPIP;



	/* store new outer network header */

	if (bpf_skb_store_bytes(skb, ETH_HLEN, &h_outer, olen,

				BPF_F_INVALIDATE_HASH) < 0)

		return TC_ACT_SHOT;



	/* update eth->h_proto */

	if (bpf_skb_load_bytes(skb, 0, &eth, sizeof(eth)) < 0)

		return TC_ACT_SHOT;

	eth.h_proto = bpf_htons(ETH_P_IPV6);

	if (bpf_skb_store_bytes(skb, 0, &eth, sizeof(eth), 0) < 0)

		return TC_ACT_SHOT;



	return TC_ACT_OK;

}



static __always_inline int encap_ipv6(struct __sk_buff *skb, __u8 encap_proto,

				      __u16 l2_proto)

{
@@ -461,6 +520,15 @@ int __encap_ip6tnl_none(struct __sk_buff *skb) 
		return TC_ACT_OK;

}



SEC("encap_ipip6_none")

int __encap_ipip6_none(struct __sk_buff *skb)

{

	if (skb->protocol == __bpf_constant_htons(ETH_P_IP))

		return encap_ipv6_ipip6(skb);

	else

		return TC_ACT_OK;

}



SEC("encap_ip6gre_none")

int __encap_ip6gre_none(struct __sk_buff *skb)

{
@@ -528,13 +596,33 @@ int __encap_ip6vxlan_eth(struct __sk_buff *skb) 


static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)

{

	__u64 flags = BPF_F_ADJ_ROOM_FIXED_GSO;

	struct ipv6_opt_hdr ip6_opt_hdr;

	struct gre_hdr greh;

	struct udphdr udph;

	int olen = len;



	switch (proto) {

	case IPPROTO_IPIP:

		flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV4;

		break;

	case IPPROTO_IPV6:

		flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV6;

		break;

	case NEXTHDR_DEST:

		if (bpf_skb_load_bytes(skb, off + len, &ip6_opt_hdr,

				       sizeof(ip6_opt_hdr)) < 0)

			return TC_ACT_OK;

		switch (ip6_opt_hdr.nexthdr) {

		case IPPROTO_IPIP:

			flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV4;

			break;

		case IPPROTO_IPV6:

			flags |= BPF_F_ADJ_ROOM_DECAP_L3_IPV6;

			break;

		default:

			return TC_ACT_OK;

		}

		break;

	case IPPROTO_GRE:

		olen += sizeof(struct gre_hdr);
@@ -569,8 +657,7 @@ static int decap_internal(struct __sk_buff *skb, int off, int len, char proto) 
		return TC_ACT_OK;

	}



	if (bpf_skb_adjust_room(skb, -olen, BPF_ADJ_ROOM_MAC,

				BPF_F_ADJ_ROOM_FIXED_GSO))

	if (bpf_skb_adjust_room(skb, -olen, BPF_ADJ_ROOM_MAC, flags))

		return TC_ACT_SHOT;



	return TC_ACT_OK;

tools/testing/selftests/bpf/test_tc_tunnel.sh

+9 −6
Original line number Diff line number Diff line
@@ -100,6 +100,9 @@ if [[ "$#" -eq "0" ]]; then 
	echo "ipip"

	$0 ipv4 ipip none 100



	echo "ipip6"

	$0 ipv4 ipip6 none 100



	echo "ip6ip6"

	$0 ipv6 ip6tnl none 100
@@ -224,6 +227,9 @@ elif [[ "$tuntype" =~ "gre" && "$mac" == "eth" ]]; then 
elif [[ "$tuntype" =~ "vxlan" && "$mac" == "eth" ]]; then

	ttype="vxlan"

	targs="id 1 dstport 8472 udp6zerocsumrx"

elif [[ "$tuntype" == "ipip6" ]]; then

	ttype="ip6tnl"

	targs=""

else

	ttype=$tuntype

	targs=""
@@ -233,6 +239,9 @@ fi 
if [[ "${tuntype}" == "sit" ]]; then

	link_addr1="${ns1_v4}"

	link_addr2="${ns2_v4}"

elif [[ "${tuntype}" == "ipip6" ]]; then

	link_addr1="${ns1_v6}"

	link_addr2="${ns2_v6}"

else

	link_addr1="${addr1}"

	link_addr2="${addr2}"
@@ -287,12 +296,6 @@ else 
	server_listen

fi



# bpf_skb_net_shrink does not take tunnel flags yet, cannot update L3.

if [[ "${tuntype}" == "sit" ]]; then

	echo OK

	exit 0

fi



# serverside, use BPF for decap

ip netns exec "${ns2}" ip link del dev testtun0

ip netns exec "${ns2}" tc qdisc add dev veth2 clsact