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Message-ID:
<AM6PR03MB58481BA6D59599AD7438B4EA99A42@AM6PR03MB5848.eurprd03.prod.outlook.com>
Date: Wed, 10 Jul 2024 19:40:54 +0100
From: Juntong Deng <juntong.deng@...look.com>
To: ast@...nel.org,
daniel@...earbox.net,
john.fastabend@...il.com,
martin.lau@...ux.dev,
eddyz87@...il.com,
song@...nel.org,
yonghong.song@...ux.dev,
kpsingh@...nel.org,
sdf@...ichev.me,
haoluo@...gle.com,
jolsa@...nel.org,
andrii@...nel.org,
avagin@...il.com,
snorcht@...il.com
Cc: bpf@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [RFC PATCH 10/16] bpf/crib: Add struct sk_buff related CRIB kfuncs
This patch adds struct sk_buff related CRIB kfuncs.
bpf_skb_peek_tail() is used to get a pointer to the skb at the tail of
the socket queue.
bpf_cal_skb_size() is used to calculate the overall size of the skb data
(starting from the head).
bpf_skb_acquire()/bpf_skb_release() are used to acquire/release
references on struct sk_buff.
Signed-off-by: Juntong Deng <juntong.deng@...look.com>
---
kernel/bpf/crib/bpf_checkpoint.c | 14 +++++++++
kernel/bpf/crib/bpf_crib.c | 50 ++++++++++++++++++++++++++++++++
2 files changed, 64 insertions(+)
diff --git a/kernel/bpf/crib/bpf_checkpoint.c b/kernel/bpf/crib/bpf_checkpoint.c
index 4d48f08324ef..d8cd4a1b73dc 100644
--- a/kernel/bpf/crib/bpf_checkpoint.c
+++ b/kernel/bpf/crib/bpf_checkpoint.c
@@ -10,6 +10,7 @@
#include <linux/fdtable.h>
#include <net/inet_common.h>
#include <net/ipv6.h>
+#include <linux/skbuff.h>
extern void bpf_file_release(struct file *file);
@@ -148,4 +149,17 @@ __bpf_kfunc int bpf_inet6_dst_addr_from_socket(struct socket *sock, struct socka
return inet6_getname(sock, (struct sockaddr *)addr, 1);
}
+/**
+ * bpf_cal_skb_size() - Calculate the overall size of the data of specified skb
+ * (starting from the head)
+ *
+ * @skb: specified skb
+ *
+ * @returns the overall size of the data
+ */
+__bpf_kfunc int bpf_cal_skb_size(struct sk_buff *skb)
+{
+ return skb_end_offset(skb) + skb->data_len;
+}
+
__bpf_kfunc_end_defs();
diff --git a/kernel/bpf/crib/bpf_crib.c b/kernel/bpf/crib/bpf_crib.c
index e33fa37f8f72..21889efa620c 100644
--- a/kernel/bpf/crib/bpf_crib.c
+++ b/kernel/bpf/crib/bpf_crib.c
@@ -13,6 +13,8 @@
#include <linux/net.h>
#include <linux/udp.h>
#include <linux/tcp.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
__bpf_kfunc_start_defs();
@@ -209,6 +211,49 @@ __bpf_kfunc struct sk_buff_head *bpf_reader_queue_from_udp_sock(struct udp_sock
return &up->reader_queue;
}
+/**
+ * bpf_skb_acquire() - Acquire a reference to struct sk_buff
+ *
+ * @skb: struct sk_buff that needs to acquire a reference
+ *
+ * @returns struct sk_buff that has acquired the reference
+ */
+__bpf_kfunc struct sk_buff *bpf_skb_acquire(struct sk_buff *skb)
+{
+ return skb_get(skb);
+}
+
+/**
+ * bpf_skb_release() - Release the reference acquired on struct sk_buff
+ *
+ * @skb: struct sk_buff that has acquired the reference
+ */
+__bpf_kfunc void bpf_skb_release(struct sk_buff *skb)
+{
+ consume_skb(skb);
+}
+
+/**
+ * bpf_skb_peek_tail() - peek at the tail of socket queue (sk_buff_head)
+ *
+ * Note that this function acquires a reference to struct sk_buff.
+ *
+ * @head: socket queue
+ *
+ * @returns pointer to the tail skb (sk_buff)
+ */
+__bpf_kfunc struct sk_buff *bpf_skb_peek_tail(struct sk_buff_head *head)
+{
+ struct sk_buff *skb;
+ unsigned long flags;
+
+ spin_lock_irqsave(&head->lock, flags);
+ skb = skb_peek_tail(head);
+ spin_unlock_irqrestore(&head->lock, flags);
+
+ return bpf_skb_acquire(skb);
+}
+
__bpf_kfunc_end_defs();
BTF_KFUNCS_START(bpf_crib_kfuncs)
@@ -239,6 +284,11 @@ BTF_ID_FLAGS(func, bpf_inet_dst_addr_from_socket, KF_TRUSTED_ARGS)
BTF_ID_FLAGS(func, bpf_inet6_src_addr_from_socket, KF_TRUSTED_ARGS)
BTF_ID_FLAGS(func, bpf_inet6_dst_addr_from_socket, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_skb_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_skb_release, KF_RELEASE)
+BTF_ID_FLAGS(func, bpf_cal_skb_size, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_skb_peek_tail, KF_ACQUIRE | KF_TRUSTED_ARGS | KF_RET_NULL)
+
BTF_KFUNCS_END(bpf_crib_kfuncs)
static int bpf_prog_run_crib(struct bpf_prog *prog,
--
2.39.2
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