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Message-ID: <CAH3MdRUTO_Cg57WqJu8qji-mxpvvL5hiBzU4Wp_rYetEXiQNMQ@mail.gmail.com>
Date: Thu, 24 May 2018 19:30:33 -0700
From: Y Song <ys114321@...il.com>
To: Mathieu Xhonneux <m.xhonneux@...il.com>
Cc: netdev <netdev@...r.kernel.org>,
Daniel Borkmann <daniel@...earbox.net>, dlebrun@...gle.com,
Alexei Starovoitov <alexei.starovoitov@...il.com>
Subject: Re: [PATCH bpf-next v7 6/6] selftests/bpf: test for seg6local End.BPF action
When compiling latest bpf-next, I hit the following compilation error:
clang -I. -I./include/uapi -I../../../include/uapi -idirafter
/usr/local/include -idirafter
/data/users/yhs/work/llvm/build/install/lib/clang/7.0.0/include
-idirafter /usr/include -Wno-compare-distinct-pointer-types \
-O2 -target bpf -emit-llvm -c test_lwt_seg6local.c -o - | \
llc -march=bpf -mcpu=generic -filetype=obj -o
/data/users/yhs/work/net-next/tools/testing/selftests/bpf/test_lwt_seg6local.o
test_lwt_seg6local.c:4:10: fatal error: 'linux/seg6_local.h' file not found
#include <linux/seg6_local.h>
^~~~~~~~~~~~~~~~~~~~
1 error generated.
make: Leaving directory
`/data/users/yhs/work/net-next/tools/testing/selftests/bpf'
Should the seg6_local.h be copied to tools/ directory?
On Sun, May 20, 2018 at 6:58 AM, Mathieu Xhonneux <m.xhonneux@...il.com> wrote:
> Add a new test for the seg6local End.BPF action. The following helpers
> are also tested:
>
> - bpf_lwt_push_encap within the LWT BPF IN hook
> - bpf_lwt_seg6_action
> - bpf_lwt_seg6_adjust_srh
> - bpf_lwt_seg6_store_bytes
>
> A chain of End.BPF actions is built. The SRH is injected through a LWT
> BPF IN hook before entering this chain. Each End.BPF action validates
> the previous one, otherwise the packet is dropped. The test succeeds
> if the last node in the chain receives the packet and the UDP datagram
> contained can be retrieved from userspace.
>
> Signed-off-by: Mathieu Xhonneux <m.xhonneux@...il.com>
> ---
> tools/include/uapi/linux/bpf.h | 97 ++++-
> tools/testing/selftests/bpf/Makefile | 6 +-
> tools/testing/selftests/bpf/bpf_helpers.h | 12 +
> tools/testing/selftests/bpf/test_lwt_seg6local.c | 437 ++++++++++++++++++++++
> tools/testing/selftests/bpf/test_lwt_seg6local.sh | 140 +++++++
> 5 files changed, 689 insertions(+), 3 deletions(-)
> create mode 100644 tools/testing/selftests/bpf/test_lwt_seg6local.c
> create mode 100755 tools/testing/selftests/bpf/test_lwt_seg6local.sh
>
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 97446bbe2ca5..b217a33d80a4 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -141,6 +141,7 @@ enum bpf_prog_type {
> BPF_PROG_TYPE_SK_MSG,
> BPF_PROG_TYPE_RAW_TRACEPOINT,
> BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
> + BPF_PROG_TYPE_LWT_SEG6LOCAL,
> };
>
> enum bpf_attach_type {
> @@ -1902,6 +1903,90 @@ union bpf_attr {
> * egress otherwise). This is the only flag supported for now.
> * Return
> * **SK_PASS** on success, or **SK_DROP** on error.
> + *
> + * int bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
> + * Description
> + * Encapsulate the packet associated to *skb* within a Layer 3
> + * protocol header. This header is provided in the buffer at
> + * address *hdr*, with *len* its size in bytes. *type* indicates
> + * the protocol of the header and can be one of:
> + *
> + * **BPF_LWT_ENCAP_SEG6**
> + * IPv6 encapsulation with Segment Routing Header
> + * (**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
> + * the IPv6 header is computed by the kernel.
> + * **BPF_LWT_ENCAP_SEG6_INLINE**
> + * Only works if *skb* contains an IPv6 packet. Insert a
> + * Segment Routing Header (**struct ipv6_sr_hdr**) inside
> + * the IPv6 header.
> + *
> + * A call to this helper is susceptible to change the underlaying
> + * packet buffer. Therefore, at load time, all checks on pointers
> + * previously done by the verifier are invalidated and must be
> + * performed again, if the helper is used in combination with
> + * direct packet access.
> + * Return
> + * 0 on success, or a negative error in case of failure.
> + *
> + * int bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
> + * Description
> + * Store *len* bytes from address *from* into the packet
> + * associated to *skb*, at *offset*. Only the flags, tag and TLVs
> + * inside the outermost IPv6 Segment Routing Header can be
> + * modified through this helper.
> + *
> + * A call to this helper is susceptible to change the underlaying
> + * packet buffer. Therefore, at load time, all checks on pointers
> + * previously done by the verifier are invalidated and must be
> + * performed again, if the helper is used in combination with
> + * direct packet access.
> + * Return
> + * 0 on success, or a negative error in case of failure.
> + *
> + * int bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
> + * Description
> + * Adjust the size allocated to TLVs in the outermost IPv6
> + * Segment Routing Header contained in the packet associated to
> + * *skb*, at position *offset* by *delta* bytes. Only offsets
> + * after the segments are accepted. *delta* can be as well
> + * positive (growing) as negative (shrinking).
> + *
> + * A call to this helper is susceptible to change the underlaying
> + * packet buffer. Therefore, at load time, all checks on pointers
> + * previously done by the verifier are invalidated and must be
> + * performed again, if the helper is used in combination with
> + * direct packet access.
> + * Return
> + * 0 on success, or a negative error in case of failure.
> + *
> + * int bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
> + * Description
> + * Apply an IPv6 Segment Routing action of type *action* to the
> + * packet associated to *skb*. Each action takes a parameter
> + * contained at address *param*, and of length *param_len* bytes.
> + * *action* can be one of:
> + *
> + * **SEG6_LOCAL_ACTION_END_X**
> + * End.X action: Endpoint with Layer-3 cross-connect.
> + * Type of *param*: **struct in6_addr**.
> + * **SEG6_LOCAL_ACTION_END_T**
> + * End.T action: Endpoint with specific IPv6 table lookup.
> + * Type of *param*: **int**.
> + * **SEG6_LOCAL_ACTION_END_B6**
> + * End.B6 action: Endpoint bound to an SRv6 policy.
> + * Type of param: **struct ipv6_sr_hdr**.
> + * **SEG6_LOCAL_ACTION_END_B6_ENCAP**
> + * End.B6.Encap action: Endpoint bound to an SRv6
> + * encapsulation policy.
> + * Type of param: **struct ipv6_sr_hdr**.
> + *
> + * A call to this helper is susceptible to change the underlaying
> + * packet buffer. Therefore, at load time, all checks on pointers
> + * previously done by the verifier are invalidated and must be
> + * performed again, if the helper is used in combination with
> + * direct packet access.
> + * Return
> + * 0 on success, or a negative error in case of failure.
> */
> #define __BPF_FUNC_MAPPER(FN) \
> FN(unspec), \
> @@ -1976,7 +2061,11 @@ union bpf_attr {
> FN(fib_lookup), \
> FN(sock_hash_update), \
> FN(msg_redirect_hash), \
> - FN(sk_redirect_hash),
> + FN(sk_redirect_hash), \
> + FN(lwt_push_encap), \
> + FN(lwt_seg6_store_bytes), \
> + FN(lwt_seg6_adjust_srh), \
> + FN(lwt_seg6_action),
>
> /* integer value in 'imm' field of BPF_CALL instruction selects which helper
> * function eBPF program intends to call
> @@ -2043,6 +2132,12 @@ enum bpf_hdr_start_off {
> BPF_HDR_START_NET,
> };
>
> +/* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
> +enum bpf_lwt_encap_mode {
> + BPF_LWT_ENCAP_SEG6,
> + BPF_LWT_ENCAP_SEG6_INLINE
> +};
> +
> /* user accessible mirror of in-kernel sk_buff.
> * new fields can only be added to the end of this structure
> */
> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index 1eb0fa2aba92..b6222b3f8fab 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -33,7 +33,8 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
> sample_map_ret0.o test_tcpbpf_kern.o test_stacktrace_build_id.o \
> sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o test_adjust_tail.o \
> test_btf_haskv.o test_btf_nokv.o test_sockmap_kern.o test_tunnel_kern.o \
> - test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o
> + test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o \
> + test_lwt_seg6local.o
>
> # Order correspond to 'make run_tests' order
> TEST_PROGS := test_kmod.sh \
> @@ -42,7 +43,8 @@ TEST_PROGS := test_kmod.sh \
> test_xdp_meta.sh \
> test_offload.py \
> test_sock_addr.sh \
> - test_tunnel.sh
> + test_tunnel.sh \
> + test_lwt_seg6local.sh
>
> # Compile but not part of 'make run_tests'
> TEST_GEN_PROGS_EXTENDED = test_libbpf_open test_sock_addr
> diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
> index 8f143dfb3700..334d3e8c5e89 100644
> --- a/tools/testing/selftests/bpf/bpf_helpers.h
> +++ b/tools/testing/selftests/bpf/bpf_helpers.h
> @@ -114,6 +114,18 @@ static int (*bpf_get_stack)(void *ctx, void *buf, int size, int flags) =
> static int (*bpf_fib_lookup)(void *ctx, struct bpf_fib_lookup *params,
> int plen, __u32 flags) =
> (void *) BPF_FUNC_fib_lookup;
> +static int (*bpf_lwt_push_encap)(void *ctx, unsigned int type, void *hdr,
> + unsigned int len) =
> + (void *) BPF_FUNC_lwt_push_encap;
> +static int (*bpf_lwt_seg6_store_bytes)(void *ctx, unsigned int offset,
> + void *from, unsigned int len) =
> + (void *) BPF_FUNC_lwt_seg6_store_bytes;
> +static int (*bpf_lwt_seg6_action)(void *ctx, unsigned int action, void *param,
> + unsigned int param_len) =
> + (void *) BPF_FUNC_lwt_seg6_action;
> +static int (*bpf_lwt_seg6_adjust_srh)(void *ctx, unsigned int offset,
> + unsigned int len) =
> + (void *) BPF_FUNC_lwt_seg6_adjust_srh;
>
> /* llvm builtin functions that eBPF C program may use to
> * emit BPF_LD_ABS and BPF_LD_IND instructions
> diff --git a/tools/testing/selftests/bpf/test_lwt_seg6local.c b/tools/testing/selftests/bpf/test_lwt_seg6local.c
> new file mode 100644
> index 000000000000..0575751bc1bc
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/test_lwt_seg6local.c
> @@ -0,0 +1,437 @@
> +#include <stddef.h>
> +#include <inttypes.h>
> +#include <errno.h>
> +#include <linux/seg6_local.h>
> +#include <linux/bpf.h>
> +#include "bpf_helpers.h"
> +#include "bpf_endian.h"
> +
> +#define bpf_printk(fmt, ...) \
> +({ \
> + char ____fmt[] = fmt; \
> + bpf_trace_printk(____fmt, sizeof(____fmt), \
> + ##__VA_ARGS__); \
> +})
> +
> +/* Packet parsing state machine helpers. */
> +#define cursor_advance(_cursor, _len) \
> + ({ void *_tmp = _cursor; _cursor += _len; _tmp; })
> +
> +#define SR6_FLAG_ALERT (1 << 4)
> +
> +#define htonll(x) ((bpf_htonl(1)) == 1 ? (x) : ((uint64_t)bpf_htonl((x) & \
> + 0xFFFFFFFF) << 32) | bpf_htonl((x) >> 32))
> +#define ntohll(x) ((bpf_ntohl(1)) == 1 ? (x) : ((uint64_t)bpf_ntohl((x) & \
> + 0xFFFFFFFF) << 32) | bpf_ntohl((x) >> 32))
> +#define BPF_PACKET_HEADER __attribute__((packed))
> +
> +struct ip6_t {
> + unsigned int ver:4;
> + unsigned int priority:8;
> + unsigned int flow_label:20;
> + unsigned short payload_len;
> + unsigned char next_header;
> + unsigned char hop_limit;
> + unsigned long long src_hi;
> + unsigned long long src_lo;
> + unsigned long long dst_hi;
> + unsigned long long dst_lo;
> +} BPF_PACKET_HEADER;
> +
> +struct ip6_addr_t {
> + unsigned long long hi;
> + unsigned long long lo;
> +} BPF_PACKET_HEADER;
> +
> +struct ip6_srh_t {
> + unsigned char nexthdr;
> + unsigned char hdrlen;
> + unsigned char type;
> + unsigned char segments_left;
> + unsigned char first_segment;
> + unsigned char flags;
> + unsigned short tag;
> +
> + struct ip6_addr_t segments[0];
> +} BPF_PACKET_HEADER;
> +
> +struct sr6_tlv_t {
> + unsigned char type;
> + unsigned char len;
> + unsigned char value[0];
> +} BPF_PACKET_HEADER;
> +
> +__attribute__((always_inline)) struct ip6_srh_t *get_srh(struct __sk_buff *skb)
> +{
> + void *cursor, *data_end;
> + struct ip6_srh_t *srh;
> + struct ip6_t *ip;
> + uint8_t *ipver;
> +
> + data_end = (void *)(long)skb->data_end;
> + cursor = (void *)(long)skb->data;
> + ipver = (uint8_t *)cursor;
> +
> + if ((void *)ipver + sizeof(*ipver) > data_end)
> + return NULL;
> +
> + if ((*ipver >> 4) != 6)
> + return NULL;
> +
> + ip = cursor_advance(cursor, sizeof(*ip));
> + if ((void *)ip + sizeof(*ip) > data_end)
> + return NULL;
> +
> + if (ip->next_header != 43)
> + return NULL;
> +
> + srh = cursor_advance(cursor, sizeof(*srh));
> + if ((void *)srh + sizeof(*srh) > data_end)
> + return NULL;
> +
> + if (srh->type != 4)
> + return NULL;
> +
> + return srh;
> +}
> +
> +__attribute__((always_inline))
> +int update_tlv_pad(struct __sk_buff *skb, uint32_t new_pad,
> + uint32_t old_pad, uint32_t pad_off)
> +{
> + int err;
> +
> + if (new_pad != old_pad) {
> + err = bpf_lwt_seg6_adjust_srh(skb, pad_off,
> + (int) new_pad - (int) old_pad);
> + if (err)
> + return err;
> + }
> +
> + if (new_pad > 0) {
> + char pad_tlv_buf[16] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
> + 0, 0, 0};
> + struct sr6_tlv_t *pad_tlv = (struct sr6_tlv_t *) pad_tlv_buf;
> +
> + pad_tlv->type = SR6_TLV_PADDING;
> + pad_tlv->len = new_pad - 2;
> +
> + err = bpf_lwt_seg6_store_bytes(skb, pad_off,
> + (void *)pad_tlv_buf, new_pad);
> + if (err)
> + return err;
> + }
> +
> + return 0;
> +}
> +
> +__attribute__((always_inline))
> +int is_valid_tlv_boundary(struct __sk_buff *skb, struct ip6_srh_t *srh,
> + uint32_t *tlv_off, uint32_t *pad_size,
> + uint32_t *pad_off)
> +{
> + uint32_t srh_off, cur_off;
> + int offset_valid = 0;
> + int err;
> +
> + srh_off = (char *)srh - (char *)(long)skb->data;
> + // cur_off = end of segments, start of possible TLVs
> + cur_off = srh_off + sizeof(*srh) +
> + sizeof(struct ip6_addr_t) * (srh->first_segment + 1);
> +
> + *pad_off = 0;
> +
> + // we can only go as far as ~10 TLVs due to the BPF max stack size
> + #pragma clang loop unroll(full)
> + for (int i = 0; i < 10; i++) {
> + struct sr6_tlv_t tlv;
> +
> + if (cur_off == *tlv_off)
> + offset_valid = 1;
> +
> + if (cur_off >= srh_off + ((srh->hdrlen + 1) << 3))
> + break;
> +
> + err = bpf_skb_load_bytes(skb, cur_off, &tlv, sizeof(tlv));
> + if (err)
> + return err;
> +
> + if (tlv.type == SR6_TLV_PADDING) {
> + *pad_size = tlv.len + sizeof(tlv);
> + *pad_off = cur_off;
> +
> + if (*tlv_off == srh_off) {
> + *tlv_off = cur_off;
> + offset_valid = 1;
> + }
> + break;
> +
> + } else if (tlv.type == SR6_TLV_HMAC) {
> + break;
> + }
> +
> + cur_off += sizeof(tlv) + tlv.len;
> + } // we reached the padding or HMAC TLVs, or the end of the SRH
> +
> + if (*pad_off == 0)
> + *pad_off = cur_off;
> +
> + if (*tlv_off == -1)
> + *tlv_off = cur_off;
> + else if (!offset_valid)
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +__attribute__((always_inline))
> +int add_tlv(struct __sk_buff *skb, struct ip6_srh_t *srh, uint32_t tlv_off,
> + struct sr6_tlv_t *itlv, uint8_t tlv_size)
> +{
> + uint32_t srh_off = (char *)srh - (char *)(long)skb->data;
> + uint8_t len_remaining, new_pad;
> + uint32_t pad_off = 0;
> + uint32_t pad_size = 0;
> + uint32_t partial_srh_len;
> + int err;
> +
> + if (tlv_off != -1)
> + tlv_off += srh_off;
> +
> + if (itlv->type == SR6_TLV_PADDING || itlv->type == SR6_TLV_HMAC)
> + return -EINVAL;
> +
> + err = is_valid_tlv_boundary(skb, srh, &tlv_off, &pad_size, &pad_off);
> + if (err)
> + return err;
> +
> + err = bpf_lwt_seg6_adjust_srh(skb, tlv_off, sizeof(*itlv) + itlv->len);
> + if (err)
> + return err;
> +
> + err = bpf_lwt_seg6_store_bytes(skb, tlv_off, (void *)itlv, tlv_size);
> + if (err)
> + return err;
> +
> + // the following can't be moved inside update_tlv_pad because the
> + // bpf verifier has some issues with it
> + pad_off += sizeof(*itlv) + itlv->len;
> + partial_srh_len = pad_off - srh_off;
> + len_remaining = partial_srh_len % 8;
> + new_pad = 8 - len_remaining;
> +
> + if (new_pad == 1) // cannot pad for 1 byte only
> + new_pad = 9;
> + else if (new_pad == 8)
> + new_pad = 0;
> +
> + return update_tlv_pad(skb, new_pad, pad_size, pad_off);
> +}
> +
> +__attribute__((always_inline))
> +int delete_tlv(struct __sk_buff *skb, struct ip6_srh_t *srh,
> + uint32_t tlv_off)
> +{
> + uint32_t srh_off = (char *)srh - (char *)(long)skb->data;
> + uint8_t len_remaining, new_pad;
> + uint32_t partial_srh_len;
> + uint32_t pad_off = 0;
> + uint32_t pad_size = 0;
> + struct sr6_tlv_t tlv;
> + int err;
> +
> + tlv_off += srh_off;
> +
> + err = is_valid_tlv_boundary(skb, srh, &tlv_off, &pad_size, &pad_off);
> + if (err)
> + return err;
> +
> + err = bpf_skb_load_bytes(skb, tlv_off, &tlv, sizeof(tlv));
> + if (err)
> + return err;
> +
> + err = bpf_lwt_seg6_adjust_srh(skb, tlv_off, -(sizeof(tlv) + tlv.len));
> + if (err)
> + return err;
> +
> + pad_off -= sizeof(tlv) + tlv.len;
> + partial_srh_len = pad_off - srh_off;
> + len_remaining = partial_srh_len % 8;
> + new_pad = 8 - len_remaining;
> + if (new_pad == 1) // cannot pad for 1 byte only
> + new_pad = 9;
> + else if (new_pad == 8)
> + new_pad = 0;
> +
> + return update_tlv_pad(skb, new_pad, pad_size, pad_off);
> +}
> +
> +__attribute__((always_inline))
> +int has_egr_tlv(struct __sk_buff *skb, struct ip6_srh_t *srh)
> +{
> + int tlv_offset = sizeof(struct ip6_t) + sizeof(struct ip6_srh_t) +
> + ((srh->first_segment + 1) << 4);
> + struct sr6_tlv_t tlv;
> +
> + if (bpf_skb_load_bytes(skb, tlv_offset, &tlv, sizeof(struct sr6_tlv_t)))
> + return 0;
> +
> + if (tlv.type == SR6_TLV_EGRESS && tlv.len == 18) {
> + struct ip6_addr_t egr_addr;
> +
> + if (bpf_skb_load_bytes(skb, tlv_offset + 4, &egr_addr, 16))
> + return 0;
> +
> + // check if egress TLV value is correct
> + if (ntohll(egr_addr.hi) == 0xfd00000000000000 &&
> + ntohll(egr_addr.lo) == 0x4)
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +// This function will push a SRH with segments fd00::1, fd00::2, fd00::3,
> +// fd00::4
> +SEC("encap_srh")
> +int __encap_srh(struct __sk_buff *skb)
> +{
> + unsigned long long hi = 0xfd00000000000000;
> + struct ip6_addr_t *seg;
> + struct ip6_srh_t *srh;
> + char srh_buf[72]; // room for 4 segments
> + int err;
> +
> + srh = (struct ip6_srh_t *)srh_buf;
> + srh->nexthdr = 0;
> + srh->hdrlen = 8;
> + srh->type = 4;
> + srh->segments_left = 3;
> + srh->first_segment = 3;
> + srh->flags = 0;
> + srh->tag = 0;
> +
> + seg = (struct ip6_addr_t *)((char *)srh + sizeof(*srh));
> +
> + #pragma clang loop unroll(full)
> + for (unsigned long long lo = 0; lo < 4; lo++) {
> + seg->lo = htonll(4 - lo);
> + seg->hi = htonll(hi);
> + seg = (struct ip6_addr_t *)((char *)seg + sizeof(*seg));
> + }
> +
> + err = bpf_lwt_push_encap(skb, 0, (void *)srh, sizeof(srh_buf));
> + if (err)
> + return BPF_DROP;
> +
> + return BPF_REDIRECT;
> +}
> +
> +// Add an Egress TLV fc00::4, add the flag A,
> +// and apply End.X action to fc42::1
> +SEC("add_egr_x")
> +int __add_egr_x(struct __sk_buff *skb)
> +{
> + unsigned long long hi = 0xfc42000000000000;
> + unsigned long long lo = 0x1;
> + struct ip6_srh_t *srh = get_srh(skb);
> + uint8_t new_flags = SR6_FLAG_ALERT;
> + struct ip6_addr_t addr;
> + int err, offset;
> +
> + if (srh == NULL)
> + return BPF_DROP;
> +
> + uint8_t tlv[20] = {2, 18, 0, 0, 0xfd, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
> + 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x4};
> +
> + err = add_tlv(skb, srh, (srh->hdrlen+1) << 3,
> + (struct sr6_tlv_t *)&tlv, 20);
> + if (err)
> + return BPF_DROP;
> +
> + offset = sizeof(struct ip6_t) + offsetof(struct ip6_srh_t, flags);
> + err = bpf_lwt_seg6_store_bytes(skb, offset,
> + (void *)&new_flags, sizeof(new_flags));
> + if (err)
> + return BPF_DROP;
> +
> + addr.lo = htonll(lo);
> + addr.hi = htonll(hi);
> + err = bpf_lwt_seg6_action(skb, SEG6_LOCAL_ACTION_END_X,
> + (void *)&addr, sizeof(addr));
> + if (err)
> + return BPF_DROP;
> + return BPF_REDIRECT;
> +}
> +
> +// Pop the Egress TLV, reset the flags, change the tag 2442 and finally do a
> +// simple End action
> +SEC("pop_egr")
> +int __pop_egr(struct __sk_buff *skb)
> +{
> + struct ip6_srh_t *srh = get_srh(skb);
> + uint16_t new_tag = bpf_htons(2442);
> + uint8_t new_flags = 0;
> + int err, offset;
> +
> + if (srh == NULL)
> + return BPF_DROP;
> +
> + if (srh->flags != SR6_FLAG_ALERT)
> + return BPF_DROP;
> +
> + if (srh->hdrlen != 11) // 4 segments + Egress TLV + Padding TLV
> + return BPF_DROP;
> +
> + if (!has_egr_tlv(skb, srh))
> + return BPF_DROP;
> +
> + err = delete_tlv(skb, srh, 8 + (srh->first_segment + 1) * 16);
> + if (err)
> + return BPF_DROP;
> +
> + offset = sizeof(struct ip6_t) + offsetof(struct ip6_srh_t, flags);
> + if (bpf_lwt_seg6_store_bytes(skb, offset, (void *)&new_flags,
> + sizeof(new_flags)))
> + return BPF_DROP;
> +
> + offset = sizeof(struct ip6_t) + offsetof(struct ip6_srh_t, tag);
> + if (bpf_lwt_seg6_store_bytes(skb, offset, (void *)&new_tag,
> + sizeof(new_tag)))
> + return BPF_DROP;
> +
> + return BPF_OK;
> +}
> +
> +// Inspect if the Egress TLV and flag have been removed, if the tag is correct,
> +// then apply a End.T action to reach the last segment
> +SEC("inspect_t")
> +int __inspect_t(struct __sk_buff *skb)
> +{
> + struct ip6_srh_t *srh = get_srh(skb);
> + int table = 117;
> + int err;
> +
> + if (srh == NULL)
> + return BPF_DROP;
> +
> + if (srh->flags != 0)
> + return BPF_DROP;
> +
> + if (srh->tag != bpf_htons(2442))
> + return BPF_DROP;
> +
> + if (srh->hdrlen != 8) // 4 segments
> + return BPF_DROP;
> +
> + err = bpf_lwt_seg6_action(skb, SEG6_LOCAL_ACTION_END_T,
> + (void *)&table, sizeof(table));
> +
> + if (err)
> + return BPF_DROP;
> +
> + return BPF_REDIRECT;
> +}
> +
> +char __license[] SEC("license") = "GPL";
> diff --git a/tools/testing/selftests/bpf/test_lwt_seg6local.sh b/tools/testing/selftests/bpf/test_lwt_seg6local.sh
> new file mode 100755
> index 000000000000..1c77994b5e71
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/test_lwt_seg6local.sh
> @@ -0,0 +1,140 @@
> +#!/bin/bash
> +# Connects 6 network namespaces through veths.
> +# Each NS may have different IPv6 global scope addresses :
> +# NS1 ---- NS2 ---- NS3 ---- NS4 ---- NS5 ---- NS6
> +# fb00::1 fd00::1 fd00::2 fd00::3 fb00::6
> +# fc42::1 fd00::4
> +#
> +# All IPv6 packets going to fb00::/16 through NS2 will be encapsulated in a
> +# IPv6 header with a Segment Routing Header, with segments :
> +# fd00::1 -> fd00::2 -> fd00::3 -> fd00::4
> +#
> +# 3 fd00::/16 IPv6 addresses are binded to seg6local End.BPF actions :
> +# - fd00::1 : add a TLV, change the flags and apply a End.X action to fc42::1
> +# - fd00::2 : remove the TLV, change the flags, add a tag
> +# - fd00::3 : apply an End.T action to fd00::4, through routing table 117
> +#
> +# fd00::4 is a simple Segment Routing node decapsulating the inner IPv6 packet.
> +# Each End.BPF action will validate the operations applied on the SRH by the
> +# previous BPF program in the chain, otherwise the packet is dropped.
> +#
> +# An UDP datagram is sent from fb00::1 to fb00::6. The test succeeds if this
> +# datagram can be read on NS6 when binding to fb00::6.
> +
> +TMP_FILE="/tmp/selftest_lwt_seg6local.txt"
> +
> +cleanup()
> +{
> + if [ "$?" = "0" ]; then
> + echo "selftests: test_lwt_seg6local [PASS]";
> + else
> + echo "selftests: test_lwt_seg6local [FAILED]";
> + fi
> +
> + set +e
> + ip netns del ns1 2> /dev/null
> + ip netns del ns2 2> /dev/null
> + ip netns del ns3 2> /dev/null
> + ip netns del ns4 2> /dev/null
> + ip netns del ns5 2> /dev/null
> + ip netns del ns6 2> /dev/null
> + rm -f $TMP_FILE
> +}
> +
> +set -e
> +
> +ip netns add ns1
> +ip netns add ns2
> +ip netns add ns3
> +ip netns add ns4
> +ip netns add ns5
> +ip netns add ns6
> +
> +trap cleanup 0 2 3 6 9
> +
> +ip link add veth1 type veth peer name veth2
> +ip link add veth3 type veth peer name veth4
> +ip link add veth5 type veth peer name veth6
> +ip link add veth7 type veth peer name veth8
> +ip link add veth9 type veth peer name veth10
> +
> +ip link set veth1 netns ns1
> +ip link set veth2 netns ns2
> +ip link set veth3 netns ns2
> +ip link set veth4 netns ns3
> +ip link set veth5 netns ns3
> +ip link set veth6 netns ns4
> +ip link set veth7 netns ns4
> +ip link set veth8 netns ns5
> +ip link set veth9 netns ns5
> +ip link set veth10 netns ns6
> +
> +ip netns exec ns1 ip link set dev veth1 up
> +ip netns exec ns2 ip link set dev veth2 up
> +ip netns exec ns2 ip link set dev veth3 up
> +ip netns exec ns3 ip link set dev veth4 up
> +ip netns exec ns3 ip link set dev veth5 up
> +ip netns exec ns4 ip link set dev veth6 up
> +ip netns exec ns4 ip link set dev veth7 up
> +ip netns exec ns5 ip link set dev veth8 up
> +ip netns exec ns5 ip link set dev veth9 up
> +ip netns exec ns6 ip link set dev veth10 up
> +ip netns exec ns6 ip link set dev lo up
> +
> +# All link scope addresses and routes required between veths
> +ip netns exec ns1 ip -6 addr add fb00::12/16 dev veth1 scope link
> +ip netns exec ns1 ip -6 route add fb00::21 dev veth1 scope link
> +ip netns exec ns2 ip -6 addr add fb00::21/16 dev veth2 scope link
> +ip netns exec ns2 ip -6 addr add fb00::34/16 dev veth3 scope link
> +ip netns exec ns2 ip -6 route add fb00::43 dev veth3 scope link
> +ip netns exec ns3 ip -6 route add fb00::65 dev veth5 scope link
> +ip netns exec ns3 ip -6 addr add fb00::43/16 dev veth4 scope link
> +ip netns exec ns3 ip -6 addr add fb00::56/16 dev veth5 scope link
> +ip netns exec ns4 ip -6 addr add fb00::65/16 dev veth6 scope link
> +ip netns exec ns4 ip -6 addr add fb00::78/16 dev veth7 scope link
> +ip netns exec ns4 ip -6 route add fb00::87 dev veth7 scope link
> +ip netns exec ns5 ip -6 addr add fb00::87/16 dev veth8 scope link
> +ip netns exec ns5 ip -6 addr add fb00::910/16 dev veth9 scope link
> +ip netns exec ns5 ip -6 route add fb00::109 dev veth9 scope link
> +ip netns exec ns5 ip -6 route add fb00::109 table 117 dev veth9 scope link
> +ip netns exec ns6 ip -6 addr add fb00::109/16 dev veth10 scope link
> +
> +ip netns exec ns1 ip -6 addr add fb00::1/16 dev lo
> +ip netns exec ns1 ip -6 route add fb00::6 dev veth1 via fb00::21
> +
> +ip netns exec ns2 ip -6 route add fb00::6 encap bpf in obj test_lwt_seg6local.o sec encap_srh dev veth2
> +ip netns exec ns2 ip -6 route add fd00::1 dev veth3 via fb00::43 scope link
> +
> +ip netns exec ns3 ip -6 route add fc42::1 dev veth5 via fb00::65
> +ip netns exec ns3 ip -6 route add fd00::1 encap seg6local action End.BPF obj test_lwt_seg6local.o sec add_egr_x dev veth4
> +
> +ip netns exec ns4 ip -6 route add fd00::2 encap seg6local action End.BPF obj test_lwt_seg6local.o sec pop_egr dev veth6
> +ip netns exec ns4 ip -6 addr add fc42::1 dev lo
> +ip netns exec ns4 ip -6 route add fd00::3 dev veth7 via fb00::87
> +
> +ip netns exec ns5 ip -6 route add fd00::4 table 117 dev veth9 via fb00::109
> +ip netns exec ns5 ip -6 route add fd00::3 encap seg6local action End.BPF obj test_lwt_seg6local.o sec inspect_t dev veth8
> +
> +ip netns exec ns6 ip -6 addr add fb00::6/16 dev lo
> +ip netns exec ns6 ip -6 addr add fd00::4/16 dev lo
> +
> +ip netns exec ns1 sysctl net.ipv6.conf.all.forwarding=1 > /dev/null
> +ip netns exec ns2 sysctl net.ipv6.conf.all.forwarding=1 > /dev/null
> +ip netns exec ns3 sysctl net.ipv6.conf.all.forwarding=1 > /dev/null
> +ip netns exec ns4 sysctl net.ipv6.conf.all.forwarding=1 > /dev/null
> +ip netns exec ns5 sysctl net.ipv6.conf.all.forwarding=1 > /dev/null
> +
> +ip netns exec ns6 sysctl net.ipv6.conf.all.seg6_enabled=1 > /dev/null
> +ip netns exec ns6 sysctl net.ipv6.conf.lo.seg6_enabled=1 > /dev/null
> +ip netns exec ns6 sysctl net.ipv6.conf.veth10.seg6_enabled=1 > /dev/null
> +
> +ip netns exec ns6 nc -l -6 -u -d 7330 > $TMP_FILE &
> +ip netns exec ns1 bash -c "echo 'foobar' | nc -w0 -6 -u -p 2121 -s fb00::1 fb00::6 7330"
> +sleep 5 # wait enough time to ensure the UDP datagram arrived to the last segment
> +kill -INT $!
> +
> +if [[ $(< $TMP_FILE) != "foobar" ]]; then
> + exit 1
> +fi
> +
> +exit 0
> --
> 2.16.1
>
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