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Message-ID: <20200727125653.31238-2-sameehj@amazon.com>
Date: Mon, 27 Jul 2020 12:56:52 +0000
From: <sameehj@...zon.com>
To: <davem@...emloft.net>, <netdev@...r.kernel.org>
CC: Sameeh Jubran <sameehj@...zon.com>, <dwmw@...zon.com>,
<zorik@...zon.com>, <matua@...zon.com>, <saeedb@...zon.com>,
<msw@...zon.com>, <aliguori@...zon.com>, <nafea@...zon.com>,
<gtzalik@...zon.com>, <netanel@...zon.com>, <alisaidi@...zon.com>,
<benh@...zon.com>, <akiyano@...zon.com>, <ndagan@...zon.com>,
<ast@...nel.org>, <daniel@...earbox.net>, <kafai@...com>,
<songliubraving@...com>, <yhs@...com>, <andriin@...com>,
<john.fastabend@...il.com>, <kpsingh@...omium.org>,
<kuba@...nel.org>, <hawk@...nel.org>, <shayagr@...zon.com>,
<lorenzo@...nel.org>
Subject: [PATCH RFC net-next 1/2] xdp: helpers: add multibuffer support
From: Sameeh Jubran <sameehj@...zon.com>
The implementation is based on this [0] draft by Jesper D. Brouer.
Provided two helpers:
* bpf_xdp_get_frag()
* bpf_xdp_get_frag_count()
[0] xdp mb design - https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org
Signed-off-by: Sameeh Jubran <sameehj@...zon.com>
---
include/uapi/linux/bpf.h | 13 +++++++++
net/core/filter.c | 60 ++++++++++++++++++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 13 +++++++++
3 files changed, 86 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 5e3863899..3484e481a 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3320,6 +3320,17 @@ union bpf_attr {
* A non-negative value equal to or less than *size* on success,
* or a negative error in case of failure.
*
+ * int bpf_xdp_get_frag(struct xdp_buff *xdp_md, u32 frag_index, u32 *size, u32 *offset)
+ * Description
+ * Get the offset from containing page and size of a given frag.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * int bpf_xdp_get_frag_count(struct xdp_buff *xdp_md)
+ * Description
+ * Get the total number of frags for a given packet.
+ * Return
+ * The number of frags
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -3464,6 +3475,8 @@ union bpf_attr {
FN(skc_to_tcp_request_sock), \
FN(skc_to_udp6_sock), \
FN(get_task_stack), \
+ FN(xdp_get_frag), \
+ FN(xdp_get_frag_count), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/net/core/filter.c b/net/core/filter.c
index bdd2382e6..93e790d7b 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3452,6 +3452,62 @@ static const struct bpf_func_proto bpf_xdp_adjust_head_proto = {
.arg2_type = ARG_ANYTHING,
};
+static inline bool __bpf_xdp_has_frags(struct xdp_buff *xdp)
+{
+ return xdp->mb != 0;
+}
+
+BPF_CALL_1(bpf_xdp_get_frag_count, struct xdp_buff*, xdp)
+{
+ return __bpf_xdp_has_frags(xdp) ?
+ ((struct skb_shared_info *)xdp->data_end)->nr_frags : 0;
+}
+
+const struct bpf_func_proto bpf_xdp_get_frag_count_proto = {
+ .func = bpf_xdp_get_frag_count,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+};
+
+BPF_CALL_4(bpf_xdp_get_frag, struct xdp_buff*, xdp, u32, frag_index,
+ u32*, size, u32*, offset)
+{
+ skb_frag_t *frags;
+ u32 frag_size;
+ u16 nr_frags;
+ struct skb_shared_info *skb_info;
+
+ if (!__bpf_xdp_has_frags(xdp))
+ return -EINVAL;
+
+ skb_info = xdp_data_hard_end(xdp);
+ frags = skb_info->frags;
+ nr_frags = skb_info->nr_frags;
+
+ if (frag_index >= nr_frags)
+ return -EINVAL;
+
+ frag_size = frags[frag_index].bv_len;
+
+ if (size)
+ memcpy(size, &frag_size, sizeof(frag_size));
+ if (offset)
+ memcpy(offset, &frags[frag_index].bv_offset, sizeof(frags[frag_index].bv_offset));
+
+ return 0;
+}
+
+const struct bpf_func_proto bpf_xdp_get_frag_proto = {
+ .func = bpf_xdp_get_frag,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+ .arg2_type = ARG_ANYTHING,
+ .arg3_type = ARG_PTR_TO_INT,
+ .arg4_type = ARG_PTR_TO_INT,
+};
+
BPF_CALL_2(bpf_xdp_adjust_tail, struct xdp_buff *, xdp, int, offset)
{
void *data_hard_end = xdp_data_hard_end(xdp); /* use xdp->frame_sz */
@@ -6475,6 +6531,10 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_xdp_redirect_map_proto;
case BPF_FUNC_xdp_adjust_tail:
return &bpf_xdp_adjust_tail_proto;
+ case BPF_FUNC_xdp_get_frag_count:
+ return &bpf_xdp_get_frag_count_proto;
+ case BPF_FUNC_xdp_get_frag:
+ return &bpf_xdp_get_frag_proto;
case BPF_FUNC_fib_lookup:
return &bpf_xdp_fib_lookup_proto;
#ifdef CONFIG_INET
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 5e3863899..3484e481a 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3320,6 +3320,17 @@ union bpf_attr {
* A non-negative value equal to or less than *size* on success,
* or a negative error in case of failure.
*
+ * int bpf_xdp_get_frag(struct xdp_buff *xdp_md, u32 frag_index, u32 *size, u32 *offset)
+ * Description
+ * Get the offset from containing page and size of a given frag.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * int bpf_xdp_get_frag_count(struct xdp_buff *xdp_md)
+ * Description
+ * Get the total number of frags for a given packet.
+ * Return
+ * The number of frags
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -3464,6 +3475,8 @@ union bpf_attr {
FN(skc_to_tcp_request_sock), \
FN(skc_to_udp6_sock), \
FN(get_task_stack), \
+ FN(xdp_get_frag), \
+ FN(xdp_get_frag_count), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
--
2.16.6
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