diff mbox series

[v8,bpf-next,09/14] bpd: add multi-buffer support to xdp copy helpers

Message ID cc517a20ac0908fa070ee6ba019936a8037a6d8c.1617885385.git.lorenzo@kernel.org (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series mvneta: introduce XDP multi-buffer support | expand

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Commit Message

Lorenzo Bianconi April 8, 2021, 12:51 p.m. UTC 
From: Eelco Chaudron <echaudro@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 <echaudro@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@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(-)

Comments

Vladimir Oltean April 8, 2021, 8:57 p.m. UTC | #1 
On Thu, Apr 08, 2021 at 02:51:01PM +0200, Lorenzo Bianconi wrote:
> From: Eelco Chaudron <echaudro@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 <echaudro@redhat.com>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
> 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;

This patch will not work without patch 10, so could you change the order?

>  } __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
>
Vladimir Oltean April 8, 2021, 9:04 p.m. UTC | #2 
On Thu, Apr 08, 2021 at 02:51:01PM +0200, Lorenzo Bianconi wrote:
> From: Eelco Chaudron <echaudro@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 <echaudro@redhat.com>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---

Also there is a typo in the commit message: bpd -> bpf.

>  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;

There is no need to cast a void pointer in C.

> +	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;

Would a static inline int xdp_buff_head_len() be useful?

> +	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;
>  }
Lorenzo Bianconi April 9, 2021, 6:19 p.m. UTC | #3 
> On Thu, Apr 08, 2021 at 02:51:01PM +0200, Lorenzo Bianconi wrote:
> > From: Eelco Chaudron <echaudro@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 <echaudro@redhat.com>
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > ---
> > 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;
> 
> This patch will not work without patch 10, so could you change the order?

ack, I will fix it in v9

Regards,
Lorenzo

> 
> >  } __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
> >
Eelco Chaudron April 14, 2021, 8:08 a.m. UTC | #4 
On 8 Apr 2021, at 23:04, Vladimir Oltean wrote:

> On Thu, Apr 08, 2021 at 02:51:01PM +0200, Lorenzo Bianconi wrote:
>> From: Eelco Chaudron <echaudro@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 <echaudro@redhat.com>
>> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
>> ---
>
> Also there is a typo in the commit message: bpd -> bpf.

ACK, will fix in next version.

>>  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;
>
> There is no need to cast a void pointer in C.

I added this as the void pointer is a const. However, looking at it 
again, we should probably change xdp_get_shared_info_from_buff() to also 
take a const pointer, i.e.:

    static inline struct xdp_shared_info *
   -xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
   +xdp_get_shared_info_from_buff(const struct xdp_buff *xdp)
    {
           BUILD_BUG_ON(sizeof(struct xdp_shared_info) >
                        sizeof(struct skb_shared_info));

What do you think Lorenzo?

>> +	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;
>
> Would a static inline int xdp_buff_head_len() be useful?

Guess everybody is using the xdp->data_end - xdp->data, in there code. 
But I guess we can add a static inline and change all code, but I 
don’t think we should do it as part of this patchset. I would also 
call it something like xdp_buff_data_len()?

>> +	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;
>>  }
diff mbox series

Patch

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,