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authorJohn Fastabend <john.fastabend@gmail.com>2018-04-23 15:39:28 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2018-04-24 00:49:45 +0200
commite20f7334837ae47341d8ec4e3170d0b4336a3676 (patch)
tree79f30f5474ae45cc9b5663316b6a5f0e1bedd028
parentba6b8de423f8d0dee48d6030288ed81c03ddf9f0 (diff)
downloadlinux-e20f7334837ae47341d8ec4e3170d0b4336a3676.tar.bz2
bpf: sockmap, sk_wait_event needed to handle blocking cases
In the recvmsg handler we need to add a wait event to support the blocking use cases. Without this we return zero and may confuse user applications. In the wait event any data received on the sk either via sk_receive_queue or the psock ingress list will wake up the sock. Fixes: fa246693a111 ("bpf: sockmap, BPF_F_INGRESS flag for BPF_SK_SKB_STREAM_VERDICT") Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
-rw-r--r--kernel/bpf/sockmap.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index a73d484b6e4c..aaf50ec77c94 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -43,6 +43,7 @@
#include <net/tcp.h>
#include <linux/ptr_ring.h>
#include <net/inet_common.h>
+#include <linux/sched/signal.h>
#define SOCK_CREATE_FLAG_MASK \
(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
@@ -732,6 +733,26 @@ out_err:
return err;
}
+static int bpf_wait_data(struct sock *sk,
+ struct smap_psock *psk, int flags,
+ long timeo, int *err)
+{
+ int rc;
+
+ DEFINE_WAIT_FUNC(wait, woken_wake_function);
+
+ add_wait_queue(sk_sleep(sk), &wait);
+ sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+ rc = sk_wait_event(sk, &timeo,
+ !list_empty(&psk->ingress) ||
+ !skb_queue_empty(&sk->sk_receive_queue),
+ &wait);
+ sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+ remove_wait_queue(sk_sleep(sk), &wait);
+
+ return rc;
+}
+
static int bpf_tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
int nonblock, int flags, int *addr_len)
{
@@ -755,6 +776,7 @@ static int bpf_tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
lock_sock(sk);
+bytes_ready:
while (copied != len) {
struct scatterlist *sg;
struct sk_msg_buff *md;
@@ -809,6 +831,28 @@ static int bpf_tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
}
}
+ if (!copied) {
+ long timeo;
+ int data;
+ int err = 0;
+
+ timeo = sock_rcvtimeo(sk, nonblock);
+ data = bpf_wait_data(sk, psock, flags, timeo, &err);
+
+ if (data) {
+ if (!skb_queue_empty(&sk->sk_receive_queue)) {
+ release_sock(sk);
+ smap_release_sock(psock, sk);
+ copied = tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
+ return copied;
+ }
+ goto bytes_ready;
+ }
+
+ if (err)
+ copied = err;
+ }
+
release_sock(sk);
smap_release_sock(psock, sk);
return copied;