@@ -228,7 +228,7 @@ struct tcp_sock {
unused:2;
u8 nonagle : 4,/* Disable Nagle algorithm? */
thin_lto : 1,/* Use linear timeouts for thin streams */
- unused1 : 1,
+ recvmsg_inq : 1,/* Indicate # of bytes in queue upon recvmsg */
repair : 1,
frto : 1;/* F-RTO (RFC5682) activated in CA_Loss */
u8 repair_queue;
@@ -1951,6 +1951,14 @@ static inline int tcp_inq(struct sock *sk)
return answ;
}
+static inline int tcp_inq_hint(const struct sock *sk)
+{
+ const struct tcp_sock *tp = tcp_sk(sk);
+
+ return max_t(int, 0,
+ READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq));
+}
+
int tcp_peek_len(struct socket *sock);
static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb)
@@ -122,6 +122,9 @@ enum {
#define TCP_MD5SIG_EXT 32 /* TCP MD5 Signature with extensions */
#define TCP_FASTOPEN_KEY 33 /* Set the key for Fast Open (cookie) */
#define TCP_FASTOPEN_NO_COOKIE 34 /* Enable TFO without a TFO cookie */
+#define TCP_INQ 35 /* Notify bytes available to read as a cmsg on read */
+
+#define TCP_CM_INQ TCP_INQ
struct tcp_repair_opt {
__u32 opt_code;
@@ -1910,13 +1910,14 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
u32 peek_seq;
u32 *seq;
unsigned long used;
- int err;
+ int err, inq;
int target; /* Read at least this many bytes */
long timeo;
struct sk_buff *skb, *last;
u32 urg_hole = 0;
struct scm_timestamping tss;
bool has_tss = false;
+ bool has_cmsg;
if (unlikely(flags & MSG_ERRQUEUE))
return inet_recv_error(sk, msg, len, addr_len);
@@ -1931,6 +1932,7 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
if (sk->sk_state == TCP_LISTEN)
goto out;
+ has_cmsg = tp->recvmsg_inq;
timeo = sock_rcvtimeo(sk, nonblock);
/* Urgent data needs to be handled specially. */
@@ -2117,6 +2119,7 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
if (TCP_SKB_CB(skb)->has_rxtstamp) {
tcp_update_recv_tstamps(skb, &tss);
has_tss = true;
+ has_cmsg = true;
}
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
goto found_fin_ok;
@@ -2136,13 +2139,20 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
* on connected socket. I was just happy when found this 8) --ANK
*/
- if (has_tss)
- tcp_recv_timestamp(msg, sk, &tss);
-
/* Clean up data we have read: This will do ACK frames. */
tcp_cleanup_rbuf(sk, copied);
release_sock(sk);
+
+ if (has_cmsg) {
+ if (has_tss)
+ tcp_recv_timestamp(msg, sk, &tss);
+ if (tp->recvmsg_inq) {
+ inq = tcp_inq_hint(sk);
+ put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq);
+ }
+ }
+
return copied;
out:
@@ -3011,6 +3021,12 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
tp->notsent_lowat = val;
sk->sk_write_space(sk);
break;
+ case TCP_INQ:
+ if (val > 1 || val < 0)
+ err = -EINVAL;
+ else
+ tp->recvmsg_inq = val;
+ break;
default:
err = -ENOPROTOOPT;
break;
@@ -3436,6 +3452,9 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
case TCP_NOTSENT_LOWAT:
val = tp->notsent_lowat;
break;
+ case TCP_INQ:
+ val = tp->recvmsg_inq;
+ break;
case TCP_SAVE_SYN:
val = tp->save_syn;
break;