raspi/linux
1
0
Fork 1
mirror of https://github.com/raspberrypi/linux.git synced 2025-12-25 03:22:39 +00:00
Code Issues Projects Releases Wiki Activity

tcp_bpf: Add sk_rmem_alloc related logic for tcp_bpf ingress redirection

Browse Source 
When we do sk_psock_verdict_apply->sk_psock_skb_ingress, an sk_msg will
be created out of the skb, and the rmem accounting of the sk_msg will be
handled by the skb.

For skmsgs in __SK_REDIRECT case of tcp_bpf_send_verdict, when redirecting
to the ingress of a socket, although we sk_rmem_schedule and add sk_msg to
the ingress_msg of sk_redir, we do not update sk_rmem_alloc. As a result,
except for the global memory limit, the rmem of sk_redir is nearly
unlimited. Thus, add sk_rmem_alloc related logic to limit the recv buffer.

Since the function sk_msg_recvmsg and __sk_psock_purge_ingress_msg are
used in these two paths. We use "msg->skb" to test whether the sk_msg is
skb backed up. If it's not, we shall do the memory accounting explicitly.

Fixes: 604326b41a ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Zijian Zhang <zijianzhang@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20241210012039.1669389-3-zijianzhang@bytedance.com
This commit is contained in:
Zijian Zhang
2024-12-10 01:20:39 +00:00
committed by Daniel Borkmann
parent 54f89b3178
commit d888b7af7c
3 changed files with 16 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
net/ipv4/tcp_bpf.c
View File

@@ -56,6 +56,7 @@ static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
}
sk_mem_charge(sk, size);
atomic_add(size, &sk->sk_rmem_alloc);
sk_msg_xfer(tmp, msg, i, size);
copied += size;
if (sge->length)
@@ -74,7 +75,8 @@ static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
if (!ret) {
msg->sg.start = i;
sk_psock_queue_msg(psock, tmp);
if (!sk_psock_queue_msg(psock, tmp))
atomic_sub(copied, &sk->sk_rmem_alloc);
sk_psock_data_ready(sk, psock);
} else {
sk_msg_free(sk, tmp);