* [PATCH bpf-next,v3 1/2] bpf: add helper for getting xfrm states
2018-04-24 14:50 [PATCH bpf-next,v3 0/2] bpf: add helper for getting xfrm states Eyal Birger
@ 2018-04-24 14:50 ` Eyal Birger
2018-04-24 14:50 ` [PATCH bpf-next,v3 2/2] samples/bpf: extend test_tunnel_bpf.sh with xfrm state test Eyal Birger
2018-04-24 21:53 ` [PATCH bpf-next,v3 0/2] bpf: add helper for getting xfrm states Daniel Borkmann
2 siblings, 0 replies; 4+ messages in thread
From: Eyal Birger @ 2018-04-24 14:50 UTC (permalink / raw)
To: netdev; +Cc: shmulik, ast, daniel, Eyal Birger
This commit introduces a helper which allows fetching xfrm state
parameters by eBPF programs attached to TC.
Prototype:
bpf_skb_get_xfrm_state(skb, index, xfrm_state, size, flags)
skb: pointer to skb
index: the index in the skb xfrm_state secpath array
xfrm_state: pointer to 'struct bpf_xfrm_state'
size: size of 'struct bpf_xfrm_state'
flags: reserved for future extensions
The helper returns 0 on success. Non zero if no xfrm state at the index
is found - or non exists at all.
struct bpf_xfrm_state currently includes the SPI, peer IPv4/IPv6
address and the reqid; it can be further extended by adding elements to
its end - indicating the populated fields by the 'size' argument -
keeping backwards compatibility.
Typical usage:
struct bpf_xfrm_state x = {};
bpf_skb_get_xfrm_state(skb, 0, &x, sizeof(x), 0);
...
Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
---
include/uapi/linux/bpf.h | 25 ++++++++++++++++++++++++-
net/core/filter.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 72 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c8383a2..e667939 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -774,6 +774,15 @@ union bpf_attr {
* @xdp_md: pointer to xdp_md
* @delta: A negative integer to be added to xdp_md.data_end
* Return: 0 on success or negative on error
+ *
+ * int bpf_skb_get_xfrm_state(skb, index, xfrm_state, size, flags)
+ * retrieve XFRM state
+ * @skb: pointer to skb
+ * @index: index of the xfrm state in the secpath
+ * @key: pointer to 'struct bpf_xfrm_state'
+ * @size: size of 'struct bpf_xfrm_state'
+ * @flags: room for future extensions
+ * Return: 0 on success or negative error
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -841,7 +850,8 @@ union bpf_attr {
FN(msg_cork_bytes), \
FN(msg_pull_data), \
FN(bind), \
- FN(xdp_adjust_tail),
+ FN(xdp_adjust_tail), \
+ FN(skb_get_xfrm_state),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
@@ -947,6 +957,19 @@ struct bpf_tunnel_key {
__u32 tunnel_label;
};
+/* user accessible mirror of in-kernel xfrm_state.
+ * new fields can only be added to the end of this structure
+ */
+struct bpf_xfrm_state {
+ __u32 reqid;
+ __u32 spi; /* Stored in network byte order */
+ __u16 family;
+ union {
+ __u32 remote_ipv4; /* Stored in network byte order */
+ __u32 remote_ipv6[4]; /* Stored in network byte order */
+ };
+};
+
/* Generic BPF return codes which all BPF program types may support.
* The values are binary compatible with their TC_ACT_* counter-part to
* provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
diff --git a/net/core/filter.c b/net/core/filter.c
index e25bc4a..8e45c6c 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -57,6 +57,7 @@
#include <net/sock_reuseport.h>
#include <net/busy_poll.h>
#include <net/tcp.h>
+#include <net/xfrm.h>
#include <linux/bpf_trace.h>
/**
@@ -3743,6 +3744,49 @@ static const struct bpf_func_proto bpf_bind_proto = {
.arg3_type = ARG_CONST_SIZE,
};
+#ifdef CONFIG_XFRM
+BPF_CALL_5(bpf_skb_get_xfrm_state, struct sk_buff *, skb, u32, index,
+ struct bpf_xfrm_state *, to, u32, size, u64, flags)
+{
+ const struct sec_path *sp = skb_sec_path(skb);
+ const struct xfrm_state *x;
+
+ if (!sp || unlikely(index >= sp->len || flags))
+ goto err_clear;
+
+ x = sp->xvec[index];
+
+ if (unlikely(size != sizeof(struct bpf_xfrm_state)))
+ goto err_clear;
+
+ to->reqid = x->props.reqid;
+ to->spi = x->id.spi;
+ to->family = x->props.family;
+ if (to->family == AF_INET6) {
+ memcpy(to->remote_ipv6, x->props.saddr.a6,
+ sizeof(to->remote_ipv6));
+ } else {
+ to->remote_ipv4 = x->props.saddr.a4;
+ }
+
+ return 0;
+err_clear:
+ memset(to, 0, size);
+ return -EINVAL;
+}
+
+static const struct bpf_func_proto bpf_skb_get_xfrm_state_proto = {
+ .func = bpf_skb_get_xfrm_state,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+ .arg2_type = ARG_ANYTHING,
+ .arg3_type = ARG_PTR_TO_UNINIT_MEM,
+ .arg4_type = ARG_CONST_SIZE,
+ .arg5_type = ARG_ANYTHING,
+};
+#endif
+
static const struct bpf_func_proto *
bpf_base_func_proto(enum bpf_func_id func_id)
{
@@ -3884,6 +3928,10 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_get_socket_cookie_proto;
case BPF_FUNC_get_socket_uid:
return &bpf_get_socket_uid_proto;
+#ifdef CONFIG_XFRM
+ case BPF_FUNC_skb_get_xfrm_state:
+ return &bpf_skb_get_xfrm_state_proto;
+#endif
default:
return bpf_base_func_proto(func_id);
}
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH bpf-next,v3 2/2] samples/bpf: extend test_tunnel_bpf.sh with xfrm state test
2018-04-24 14:50 [PATCH bpf-next,v3 0/2] bpf: add helper for getting xfrm states Eyal Birger
2018-04-24 14:50 ` [PATCH bpf-next,v3 1/2] " Eyal Birger
@ 2018-04-24 14:50 ` Eyal Birger
2018-04-24 21:53 ` [PATCH bpf-next,v3 0/2] bpf: add helper for getting xfrm states Daniel Borkmann
2 siblings, 0 replies; 4+ messages in thread
From: Eyal Birger @ 2018-04-24 14:50 UTC (permalink / raw)
To: netdev; +Cc: shmulik, ast, daniel, Eyal Birger
Add a test for fetching xfrm state parameters from a tc program running
on ingress.
Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
---
samples/bpf/tcbpf2_kern.c | 16 +++++++
samples/bpf/test_tunnel_bpf.sh | 71 +++++++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 25 ++++++++++-
tools/testing/selftests/bpf/bpf_helpers.h | 4 +-
4 files changed, 114 insertions(+), 2 deletions(-)
diff --git a/samples/bpf/tcbpf2_kern.c b/samples/bpf/tcbpf2_kern.c
index 9a8db7bd..fa260c7 100644
--- a/samples/bpf/tcbpf2_kern.c
+++ b/samples/bpf/tcbpf2_kern.c
@@ -593,4 +593,20 @@ int _ip6ip6_get_tunnel(struct __sk_buff *skb)
return TC_ACT_OK;
}
+SEC("xfrm_get_state")
+int _xfrm_get_state(struct __sk_buff *skb)
+{
+ struct bpf_xfrm_state x;
+ char fmt[] = "reqid %d spi 0x%x remote ip 0x%x\n";
+ int ret;
+
+ ret = bpf_skb_get_xfrm_state(skb, 0, &x, sizeof(x), 0);
+ if (ret < 0)
+ return TC_ACT_OK;
+
+ bpf_trace_printk(fmt, sizeof(fmt), x.reqid, bpf_ntohl(x.spi),
+ bpf_ntohl(x.remote_ipv4));
+ return TC_ACT_OK;
+}
+
char _license[] SEC("license") = "GPL";
diff --git a/samples/bpf/test_tunnel_bpf.sh b/samples/bpf/test_tunnel_bpf.sh
index c265863..9c534dc 100755
--- a/samples/bpf/test_tunnel_bpf.sh
+++ b/samples/bpf/test_tunnel_bpf.sh
@@ -155,6 +155,57 @@ function add_ipip_tunnel {
ip addr add dev $DEV 10.1.1.200/24
}
+function setup_xfrm_tunnel {
+ auth=0x$(printf '1%.0s' {1..40})
+ enc=0x$(printf '2%.0s' {1..32})
+ spi_in_to_out=0x1
+ spi_out_to_in=0x2
+ # in namespace
+ # in -> out
+ ip netns exec at_ns0 \
+ ip xfrm state add src 172.16.1.100 dst 172.16.1.200 proto esp \
+ spi $spi_in_to_out reqid 1 mode tunnel \
+ auth-trunc 'hmac(sha1)' $auth 96 enc 'cbc(aes)' $enc
+ ip netns exec at_ns0 \
+ ip xfrm policy add src 10.1.1.100/32 dst 10.1.1.200/32 dir out \
+ tmpl src 172.16.1.100 dst 172.16.1.200 proto esp reqid 1 \
+ mode tunnel
+ # out -> in
+ ip netns exec at_ns0 \
+ ip xfrm state add src 172.16.1.200 dst 172.16.1.100 proto esp \
+ spi $spi_out_to_in reqid 2 mode tunnel \
+ auth-trunc 'hmac(sha1)' $auth 96 enc 'cbc(aes)' $enc
+ ip netns exec at_ns0 \
+ ip xfrm policy add src 10.1.1.200/32 dst 10.1.1.100/32 dir in \
+ tmpl src 172.16.1.200 dst 172.16.1.100 proto esp reqid 2 \
+ mode tunnel
+ # address & route
+ ip netns exec at_ns0 \
+ ip addr add dev veth0 10.1.1.100/32
+ ip netns exec at_ns0 \
+ ip route add 10.1.1.200 dev veth0 via 172.16.1.200 \
+ src 10.1.1.100
+
+ # out of namespace
+ # in -> out
+ ip xfrm state add src 172.16.1.100 dst 172.16.1.200 proto esp \
+ spi $spi_in_to_out reqid 1 mode tunnel \
+ auth-trunc 'hmac(sha1)' $auth 96 enc 'cbc(aes)' $enc
+ ip xfrm policy add src 10.1.1.100/32 dst 10.1.1.200/32 dir in \
+ tmpl src 172.16.1.100 dst 172.16.1.200 proto esp reqid 1 \
+ mode tunnel
+ # out -> in
+ ip xfrm state add src 172.16.1.200 dst 172.16.1.100 proto esp \
+ spi $spi_out_to_in reqid 2 mode tunnel \
+ auth-trunc 'hmac(sha1)' $auth 96 enc 'cbc(aes)' $enc
+ ip xfrm policy add src 10.1.1.200/32 dst 10.1.1.100/32 dir out \
+ tmpl src 172.16.1.200 dst 172.16.1.100 proto esp reqid 2 \
+ mode tunnel
+ # address & route
+ ip addr add dev veth1 10.1.1.200/32
+ ip route add 10.1.1.100 dev veth1 via 172.16.1.100 src 10.1.1.200
+}
+
function attach_bpf {
DEV=$1
SET_TUNNEL=$2
@@ -278,6 +329,22 @@ function test_ipip {
cleanup
}
+function test_xfrm_tunnel {
+ config_device
+ tcpdump -nei veth1 ip &
+ output=$(mktemp)
+ cat /sys/kernel/debug/tracing/trace_pipe | tee $output &
+ setup_xfrm_tunnel
+ tc qdisc add dev veth1 clsact
+ tc filter add dev veth1 proto ip ingress bpf da obj tcbpf2_kern.o \
+ sec xfrm_get_state
+ ip netns exec at_ns0 ping -c 1 10.1.1.200
+ grep "reqid 1" $output
+ grep "spi 0x1" $output
+ grep "remote ip 0xac100164" $output
+ cleanup
+}
+
function cleanup {
set +ex
pkill iperf
@@ -291,6 +358,8 @@ function cleanup {
ip link del geneve11
ip link del erspan11
ip link del ip6erspan11
+ ip x s flush
+ ip x p flush
pkill tcpdump
pkill cat
set -ex
@@ -316,4 +385,6 @@ echo "Testing GENEVE tunnel..."
test_geneve
echo "Testing IPIP tunnel..."
test_ipip
+echo "Testing IPSec tunnel..."
+test_xfrm_tunnel
echo "*** PASS ***"
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 7f7fbb9..5841ed4 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -774,6 +774,15 @@ union bpf_attr {
* @xdp_md: pointer to xdp_md
* @delta: A negative integer to be added to xdp_md.data_end
* Return: 0 on success or negative on error
+ *
+ * int bpf_skb_get_xfrm_state(skb, index, xfrm_state, size, flags)
+ * retrieve XFRM state
+ * @skb: pointer to skb
+ * @index: index of the xfrm state in the secpath
+ * @key: pointer to 'struct bpf_xfrm_state'
+ * @size: size of 'struct bpf_xfrm_state'
+ * @flags: room for future extensions
+ * Return: 0 on success or negative error
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -841,7 +850,8 @@ union bpf_attr {
FN(msg_cork_bytes), \
FN(msg_pull_data), \
FN(bind), \
- FN(xdp_adjust_tail),
+ FN(xdp_adjust_tail), \
+ FN(skb_get_xfrm_state),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
@@ -946,6 +956,19 @@ struct bpf_tunnel_key {
__u32 tunnel_label;
};
+/* user accessible mirror of in-kernel xfrm_state.
+ * new fields can only be added to the end of this structure
+ */
+struct bpf_xfrm_state {
+ __u32 reqid;
+ __u32 spi; /* Stored in network byte order */
+ __u16 family;
+ union {
+ __u32 remote_ipv4; /* Stored in network byte order */
+ __u32 remote_ipv6[4]; /* Stored in network byte order */
+ };
+};
+
/* Generic BPF return codes which all BPF program types may support.
* The values are binary compatible with their TC_ACT_* counter-part to
* provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
index 9271576..69d7b91 100644
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -98,7 +98,9 @@ static int (*bpf_bind)(void *ctx, void *addr, int addr_len) =
(void *) BPF_FUNC_bind;
static int (*bpf_xdp_adjust_tail)(void *ctx, int offset) =
(void *) BPF_FUNC_xdp_adjust_tail;
-
+static int (*bpf_skb_get_xfrm_state)(void *ctx, int index, void *state,
+ int size, int flags) =
+ (void *) BPF_FUNC_skb_get_xfrm_state;
/* llvm builtin functions that eBPF C program may use to
* emit BPF_LD_ABS and BPF_LD_IND instructions
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH bpf-next,v3 0/2] bpf: add helper for getting xfrm states
2018-04-24 14:50 [PATCH bpf-next,v3 0/2] bpf: add helper for getting xfrm states Eyal Birger
2018-04-24 14:50 ` [PATCH bpf-next,v3 1/2] " Eyal Birger
2018-04-24 14:50 ` [PATCH bpf-next,v3 2/2] samples/bpf: extend test_tunnel_bpf.sh with xfrm state test Eyal Birger
@ 2018-04-24 21:53 ` Daniel Borkmann
2 siblings, 0 replies; 4+ messages in thread
From: Daniel Borkmann @ 2018-04-24 21:53 UTC (permalink / raw)
To: Eyal Birger, netdev; +Cc: shmulik, ast
On 04/24/2018 04:50 PM, Eyal Birger wrote:
> This patchset adds support for fetching XFRM state information from
> an eBPF program called from TC.
>
> The first patch introduces a helper for fetching an XFRM state from the
> skb's secpath. The XFRM state is modeled using a new virtual struct which
> contains the SPI, peer address, and reqid values of the state; This struct
> can be extended in the future to provide additional state information.
>
> The second patch adds a test example in test_tunnel_bpf.sh. The sample
> validates the correct extraction of state information by the eBPF program.
>
> ---
> v3:
> - Kept SPI and peer IPv4 address in state in network byte order
> following suggestion from Alexei Starovoitov
> v2:
> - Fixed two comments by Daniel Borkmann:
> - disallow reserved flags in helper call
> - avoid compiling in helper code when CONFIG_XFRM is off
Applied to bpf-next, thanks Eyal!
^ permalink raw reply [flat|nested] 4+ messages in thread