From: Eelco Chaudron <echau...@redhat.com>

This patch adds support for multi-buffer for the following helpers:
  - bpf_xdp_output()
  - bpf_perf_event_output()

Signed-off-by: Eelco Chaudron <echau...@redhat.com>
Signed-off-by: Lorenzo Bianconi <lore...@kernel.org>
---
 net/core/filter.c                             |  63 ++++++++-
 .../selftests/bpf/prog_tests/xdp_bpf2bpf.c    | 127 ++++++++++++------
 .../selftests/bpf/progs/test_xdp_bpf2bpf.c    |   3 +-
 3 files changed, 149 insertions(+), 44 deletions(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index c4eb1392f88e..c00f52ab2532 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4549,10 +4549,56 @@ static const struct bpf_func_proto 
bpf_sk_ancestor_cgroup_id_proto = {
 };
 #endif
 
-static unsigned long bpf_xdp_copy(void *dst_buff, const void *src_buff,
+static unsigned long bpf_xdp_copy(void *dst_buff, const void *ctx,
                                  unsigned long off, unsigned long len)
 {
-       memcpy(dst_buff, src_buff + off, len);
+       struct xdp_buff *xdp = (struct xdp_buff *)ctx;
+       struct xdp_shared_info *xdp_sinfo;
+       unsigned long base_len;
+
+       if (likely(!xdp->mb)) {
+               memcpy(dst_buff, xdp->data + off, len);
+               return 0;
+       }
+
+       base_len = xdp->data_end - xdp->data;
+       xdp_sinfo = xdp_get_shared_info_from_buff(xdp);
+       do {
+               const void *src_buff = NULL;
+               unsigned long copy_len = 0;
+
+               if (off < base_len) {
+                       src_buff = xdp->data + off;
+                       copy_len = min(len, base_len - off);
+               } else {
+                       unsigned long frag_off_total = base_len;
+                       int i;
+
+                       for (i = 0; i < xdp_sinfo->nr_frags; i++) {
+                               skb_frag_t *frag = &xdp_sinfo->frags[i];
+                               unsigned long frag_len, frag_off;
+
+                               frag_len = xdp_get_frag_size(frag);
+                               frag_off = off - frag_off_total;
+                               if (frag_off < frag_len) {
+                                       src_buff = xdp_get_frag_address(frag) +
+                                                  frag_off;
+                                       copy_len = min(len,
+                                                      frag_len - frag_off);
+                                       break;
+                               }
+                               frag_off_total += frag_len;
+                       }
+               }
+               if (!src_buff)
+                       break;
+
+               memcpy(dst_buff, src_buff, copy_len);
+               off += copy_len;
+               len -= copy_len;
+               dst_buff += copy_len;
+       } while (len);
+
        return 0;
 }
 
@@ -4564,10 +4610,19 @@ BPF_CALL_5(bpf_xdp_event_output, struct xdp_buff *, 
xdp, struct bpf_map *, map,
        if (unlikely(flags & ~(BPF_F_CTXLEN_MASK | BPF_F_INDEX_MASK)))
                return -EINVAL;
        if (unlikely(!xdp ||
-                    xdp_size > (unsigned long)(xdp->data_end - xdp->data)))
+                    (likely(!xdp->mb) &&
+                     xdp_size > (unsigned long)(xdp->data_end - xdp->data))))
                return -EFAULT;
+       if (unlikely(xdp->mb)) {
+               struct xdp_shared_info *xdp_sinfo;
+
+               xdp_sinfo = xdp_get_shared_info_from_buff(xdp);
+               if (unlikely(xdp_size > ((int)(xdp->data_end - xdp->data) +
+                                        xdp_sinfo->data_length)))
+                       return -EFAULT;
+       }
 
-       return bpf_event_output(map, flags, meta, meta_size, xdp->data,
+       return bpf_event_output(map, flags, meta, meta_size, xdp,
                                xdp_size, bpf_xdp_copy);
 }
 
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c 
b/tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c
index 2c6c570b21f8..355e64526f3f 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c
@@ -10,11 +10,20 @@ struct meta {
        int pkt_len;
 };
 
+struct test_ctx_s {
+       bool passed;
+       int pkt_size;
+};
+
+struct test_ctx_s test_ctx;
+
 static void on_sample(void *ctx, int cpu, void *data, __u32 size)
 {
-       int duration = 0;
        struct meta *meta = (struct meta *)data;
        struct ipv4_packet *trace_pkt_v4 = data + sizeof(*meta);
+       unsigned char *raw_pkt = data + sizeof(*meta);
+       struct test_ctx_s *tst_ctx = ctx;
+       int duration = 0;
 
        if (CHECK(size < sizeof(pkt_v4) + sizeof(*meta),
                  "check_size", "size %u < %zu\n",
@@ -25,25 +34,90 @@ static void on_sample(void *ctx, int cpu, void *data, __u32 
size)
                  "meta->ifindex = %d\n", meta->ifindex))
                return;
 
-       if (CHECK(meta->pkt_len != sizeof(pkt_v4), "check_meta_pkt_len",
-                 "meta->pkt_len = %zd\n", sizeof(pkt_v4)))
+       if (CHECK(meta->pkt_len != tst_ctx->pkt_size, "check_meta_pkt_len",
+                 "meta->pkt_len = %d\n", tst_ctx->pkt_size))
                return;
 
        if (CHECK(memcmp(trace_pkt_v4, &pkt_v4, sizeof(pkt_v4)),
                  "check_packet_content", "content not the same\n"))
                return;
 
-       *(bool *)ctx = true;
+       if (meta->pkt_len > sizeof(pkt_v4)) {
+               for (int i = 0; i < (meta->pkt_len - sizeof(pkt_v4)); i++) {
+                       if (raw_pkt[i + sizeof(pkt_v4)] != (unsigned char)i) {
+                               CHECK(true, "check_packet_content",
+                                     "byte %zu does not match %u != %u\n",
+                                     i + sizeof(pkt_v4),
+                                     raw_pkt[i + sizeof(pkt_v4)],
+                                     (unsigned char)i);
+                               break;
+                       }
+               }
+       }
+
+       tst_ctx->passed = true;
 }
 
-void test_xdp_bpf2bpf(void)
+static int run_xdp_bpf2bpf_pkt_size(int pkt_fd, struct perf_buffer *pb,
+                                   struct test_xdp_bpf2bpf *ftrace_skel,
+                                   int pkt_size)
 {
        __u32 duration = 0, retval, size;
-       char buf[128];
+       unsigned char buf_in[9000];
+       unsigned char buf[9000];
+       int err;
+
+       if (pkt_size > sizeof(buf_in) || pkt_size < sizeof(pkt_v4))
+               return -EINVAL;
+
+       test_ctx.passed = false;
+       test_ctx.pkt_size = pkt_size;
+
+       memcpy(buf_in, &pkt_v4, sizeof(pkt_v4));
+       if (pkt_size > sizeof(pkt_v4)) {
+               for (int i = 0; i < (pkt_size - sizeof(pkt_v4)); i++)
+                       buf_in[i + sizeof(pkt_v4)] = i;
+       }
+
+       /* Run test program */
+       err = bpf_prog_test_run(pkt_fd, 1, buf_in, pkt_size,
+                               buf, &size, &retval, &duration);
+
+       if (CHECK(err || retval != XDP_PASS || size != pkt_size,
+                 "ipv4", "err %d errno %d retval %d size %d\n",
+                 err, errno, retval, size))
+               return -1;
+
+       /* Make sure bpf_xdp_output() was triggered and it sent the expected
+        * data to the perf ring buffer.
+        */
+       err = perf_buffer__poll(pb, 100);
+       if (CHECK(err <= 0, "perf_buffer__poll", "err %d\n", err))
+               return -1;
+
+       if (CHECK_FAIL(!test_ctx.passed))
+               return -1;
+
+       /* Verify test results */
+       if (CHECK(ftrace_skel->bss->test_result_fentry != if_nametoindex("lo"),
+                 "result", "fentry failed err %llu\n",
+                 ftrace_skel->bss->test_result_fentry))
+               return -1;
+
+       if (CHECK(ftrace_skel->bss->test_result_fexit != XDP_PASS, "result",
+                 "fexit failed err %llu\n",
+                 ftrace_skel->bss->test_result_fexit))
+               return -1;
+
+       return 0;
+}
+
+void test_xdp_bpf2bpf(void)
+{
        int err, pkt_fd, map_fd;
-       bool passed = false;
-       struct iphdr *iph = (void *)buf + sizeof(struct ethhdr);
-       struct iptnl_info value4 = {.family = AF_INET};
+       __u32 duration = 0;
+       int pkt_sizes[] = {sizeof(pkt_v4), 1024, 4100, 8200};
+       struct iptnl_info value4 = {.family = AF_INET6};
        struct test_xdp *pkt_skel = NULL;
        struct test_xdp_bpf2bpf *ftrace_skel = NULL;
        struct vip key4 = {.protocol = 6, .family = AF_INET};
@@ -87,40 +161,15 @@ void test_xdp_bpf2bpf(void)
 
        /* Set up perf buffer */
        pb_opts.sample_cb = on_sample;
-       pb_opts.ctx = &passed;
+       pb_opts.ctx = &test_ctx;
        pb = perf_buffer__new(bpf_map__fd(ftrace_skel->maps.perf_buf_map),
-                             1, &pb_opts);
+                             8, &pb_opts);
        if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb)))
                goto out;
 
-       /* Run test program */
-       err = bpf_prog_test_run(pkt_fd, 1, &pkt_v4, sizeof(pkt_v4),
-                               buf, &size, &retval, &duration);
-
-       if (CHECK(err || retval != XDP_TX || size != 74 ||
-                 iph->protocol != IPPROTO_IPIP, "ipv4",
-                 "err %d errno %d retval %d size %d\n",
-                 err, errno, retval, size))
-               goto out;
-
-       /* Make sure bpf_xdp_output() was triggered and it sent the expected
-        * data to the perf ring buffer.
-        */
-       err = perf_buffer__poll(pb, 100);
-       if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
-               goto out;
-
-       CHECK_FAIL(!passed);
-
-       /* Verify test results */
-       if (CHECK(ftrace_skel->bss->test_result_fentry != if_nametoindex("lo"),
-                 "result", "fentry failed err %llu\n",
-                 ftrace_skel->bss->test_result_fentry))
-               goto out;
-
-       CHECK(ftrace_skel->bss->test_result_fexit != XDP_TX, "result",
-             "fexit failed err %llu\n", ftrace_skel->bss->test_result_fexit);
-
+       for (int i = 0; i < ARRAY_SIZE(pkt_sizes); i++)
+               run_xdp_bpf2bpf_pkt_size(pkt_fd, pb, ftrace_skel,
+                                        pkt_sizes[i]);
 out:
        if (pb)
                perf_buffer__free(pb);
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c 
b/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
index a038e827f850..d5a5f603d252 100644
--- a/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
+++ b/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
@@ -27,6 +27,7 @@ struct xdp_buff {
        void *data_hard_start;
        unsigned long handle;
        struct xdp_rxq_info *rxq;
+       __u32 frame_length;
 } __attribute__((preserve_access_index));
 
 struct meta {
@@ -49,7 +50,7 @@ int BPF_PROG(trace_on_entry, struct xdp_buff *xdp)
        void *data = (void *)(long)xdp->data;
 
        meta.ifindex = xdp->rxq->dev->ifindex;
-       meta.pkt_len = data_end - data;
+       meta.pkt_len = xdp->frame_length;
        bpf_xdp_output(xdp, &perf_buf_map,
                       ((__u64) meta.pkt_len << 32) |
                       BPF_F_CURRENT_CPU,
-- 
2.30.2

Reply via email to