[PATCH bpf-next v2] selftests/bpf: add options and frags to xdp_hw_metadata

From: Larysa Zaremba
Date: Tue Oct 17 2023 - 12:35:46 EST

This is a follow-up to the commit 9b2b86332a9b ("bpf: Allow to use kfunc
XDP hints and frags together").

The are some possible implementations problems that may arise when
providing metadata specifically for multi-buffer packets, therefore there
must be a possibility to test such option separately.

Add an option to use multi-buffer AF_XDP xdp_hw_metadata and mark used XDP
program as capable to use frags.

As for now, xdp_hw_metadata accepts no options, so add simple option
parsing logic and a help message.

For quick reference, also add an ingress packet generation command to the
help message. The command comes from [0].

Example of output for multi-buffer packet:

xsk_ring_cons__peek: 1
0xead018: rx_desc[15]->addr=10000000000f000 addr=f100 comp_addr=f000
rx_hash: 0x5789FCBB with RSS type:0x29
rx_timestamp: 1696856851535324697 (sec:1696856851.5353)
XDP RX-time: 1696856843158256391 (sec:1696856843.1583)
delta sec:-8.3771 (-8377068.306 usec)
AF_XDP time: 1696856843158413078 (sec:1696856843.1584)
delta sec:0.0002 (156.687 usec)
0xead018: complete idx=23 addr=f000
xsk_ring_cons__peek: 1
0xead018: rx_desc[16]->addr=100000000008000 addr=8100 comp_addr=8000
0xead018: complete idx=24 addr=8000
xsk_ring_cons__peek: 1
0xead018: rx_desc[17]->addr=100000000009000 addr=9100 comp_addr=9000 EoP
0xead018: complete idx=25 addr=9000

Metadata is printed for the first packet only.

[0] https://lore.kernel.org/all/20230119221536.3349901-18-sdf@xxxxxxxxxx/

Signed-off-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx>
---
V1 -> V2: drop gen_socket_config(), remove extra spaces in help message

.../selftests/bpf/progs/xdp_hw_metadata.c | 2 +-
tools/testing/selftests/bpf/xdp_hw_metadata.c | 78 ++++++++++++++++---
2 files changed, 67 insertions(+), 13 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
index 63d7de6c6bbb..8767d919c881 100644
--- a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
+++ b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
@@ -21,7 +21,7 @@ extern int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx,
extern int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, __u32 *hash,
enum xdp_rss_hash_type *rss_type) __ksym;

-SEC("xdp")
+SEC("xdp.frags")
int rx(struct xdp_md *ctx)
{
void *data, *data_meta, *data_end;
diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c b/tools/testing/selftests/bpf/xdp_hw_metadata.c
index 17c980138796..17c0f92ff160 100644
--- a/tools/testing/selftests/bpf/xdp_hw_metadata.c
+++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
@@ -26,6 +26,7 @@
#include <linux/sockios.h>
#include <sys/mman.h>
#include <net/if.h>
+#include <ctype.h>
#include <poll.h>
#include <time.h>

@@ -47,6 +48,7 @@ struct xsk {
};

struct xdp_hw_metadata *bpf_obj;
+__u16 bind_flags = XDP_COPY;
struct xsk *rx_xsk;
const char *ifname;
int ifindex;
@@ -60,7 +62,7 @@ static int open_xsk(int ifindex, struct xsk *xsk, __u32 queue_id)
const struct xsk_socket_config socket_config = {
.rx_size = XSK_RING_PROD__DEFAULT_NUM_DESCS,
.tx_size = XSK_RING_PROD__DEFAULT_NUM_DESCS,
- .bind_flags = XDP_COPY,
+ .bind_flags = bind_flags,
};
const struct xsk_umem_config umem_config = {
.fill_size = XSK_RING_PROD__DEFAULT_NUM_DESCS,
@@ -263,11 +265,14 @@ static int verify_metadata(struct xsk *rx_xsk, int rxq, int server_fd, clockid_t
verify_skb_metadata(server_fd);

for (i = 0; i < rxq; i++) {
+ bool first_seg = true;
+ bool is_eop = true;
+
if (fds[i].revents == 0)
continue;

struct xsk *xsk = &rx_xsk[i];
-
+peek:
ret = xsk_ring_cons__peek(&xsk->rx, 1, &idx);
printf("xsk_ring_cons__peek: %d\n", ret);
if (ret != 1)
@@ -276,12 +281,19 @@ static int verify_metadata(struct xsk *rx_xsk, int rxq, int server_fd, clockid_t
rx_desc = xsk_ring_cons__rx_desc(&xsk->rx, idx);
comp_addr = xsk_umem__extract_addr(rx_desc->addr);
addr = xsk_umem__add_offset_to_addr(rx_desc->addr);
- printf("%p: rx_desc[%u]->addr=%llx addr=%llx comp_addr=%llx\n",
- xsk, idx, rx_desc->addr, addr, comp_addr);
- verify_xdp_metadata(xsk_umem__get_data(xsk->umem_area, addr),
- clock_id);
+ is_eop = !(rx_desc->options & XDP_PKT_CONTD);
+ printf("%p: rx_desc[%u]->addr=%llx addr=%llx comp_addr=%llx%s\n",
+ xsk, idx, rx_desc->addr, addr, comp_addr, is_eop ? " EoP" : "");
+ if (first_seg) {
+ verify_xdp_metadata(xsk_umem__get_data(xsk->umem_area, addr),
+ clock_id);
+ first_seg = false;
+ }
+
xsk_ring_cons__release(&xsk->rx, 1);
refill_rx(xsk, comp_addr);
+ if (!is_eop)
+ goto peek;
}
}

@@ -404,6 +416,53 @@ static void timestamping_enable(int fd, int val)
error(1, errno, "setsockopt(SO_TIMESTAMPING)");
}

+static void print_usage(void)
+{
+ const char *usage =
+ "Usage: xdp_hw_metadata [OPTIONS] [IFNAME]\n"
+ " -m Enable multi-buffer XDP for larger MTU\n"
+ " -h Display this help and exit\n\n"
+ "Generate test packets on the other machine with:\n"
+ " echo -n xdp | nc -u -q1 <dst_ip> 9091\n";
+
+ printf("%s", usage);
+}
+
+static void read_args(int argc, char *argv[])
+{
+ char opt;
+
+ while ((opt = getopt(argc, argv, "mh")) != -1) {
+ switch (opt) {
+ case 'm':
+ bind_flags |= XDP_USE_SG;
+ break;
+ case 'h':
+ print_usage();
+ exit(0);
+ case '?':
+ if (isprint(optopt))
+ fprintf(stderr, "Unknown option: -%c\n", optopt);
+ fallthrough;
+ default:
+ print_usage();
+ error(-1, opterr, "Command line options error");
+ }
+ }
+
+ if (optind >= argc) {
+ fprintf(stderr, "No device name provided\n");
+ print_usage();
+ exit(-1);
+ }
+
+ ifname = argv[optind];
+ ifindex = if_nametoindex(ifname);
+
+ if (!ifname)
+ error(-1, errno, "Invalid interface name");
+}
+
int main(int argc, char *argv[])
{
clockid_t clock_id = CLOCK_TAI;
@@ -413,13 +472,8 @@ int main(int argc, char *argv[])

struct bpf_program *prog;

- if (argc != 2) {
- fprintf(stderr, "pass device name\n");
- return -1;
- }
+ read_args(argc, argv);

- ifname = argv[1];
- ifindex = if_nametoindex(ifname);
rxq = rxq_num(ifname);

printf("rxq: %d\n", rxq);
--
2.41.0