Some Congestion Control modules can provide per flow information,
but current way to get this information is to use netlink.
Like TCP_INFO, let's add TCP_CC_INFO so that applications can
issue a getsockopt() if they have a socket file descriptor,
instead of playing complex netlink games.
Sample usage would be :
union tcp_cc_info info;
socklen_t len = sizeof(info);
if (getsockopt(fd, SOL_TCP, TCP_CC_INFO, &info, &len) == -1)
Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Yuchung Cheng <ych...@google.com>
Cc: Neal Cardwell <ncardw...@google.com>
---
include/uapi/linux/tcp.h | 1 +
net/ipv4/tcp.c | 21 +++++++++++++++++++++
2 files changed, 22 insertions(+)
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index 3b9718328d8b..937ec387276f 100644
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -112,6 +112,7 @@ enum {
#define TCP_FASTOPEN 23 /* Enable FastOpen on listeners */
#define TCP_TIMESTAMP 24
#define TCP_NOTSENT_LOWAT 25 /* limit number of unsent bytes in
write queue */
+#define TCP_CC_INFO 26 /* Get Congestion Control (optional)
info */
struct tcp_repair_opt {
__u32 opt_code;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 8c5cd9efebbc..1e06c75a6837 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -252,6 +252,7 @@
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/poll.h>
+#include <linux/inet_diag.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/skbuff.h>
@@ -2734,6 +2735,26 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
return -EFAULT;
return 0;
}
+ case TCP_CC_INFO: {
+ const struct tcp_congestion_ops *ca_ops;
+ union tcp_cc_info info;
+ size_t sz = 0;
+ int attr;
+
+ if (get_user(len, optlen))
+ return -EFAULT;
+
+ ca_ops = icsk->icsk_ca_ops;
+ if (ca_ops && ca_ops->get_info)
+ sz = ca_ops->get_info(sk, ~0U, &attr, &info);
+
+ len = min_t(unsigned int, len, sz);
+ if (put_user(len, optlen))
+ return -EFAULT;
+ if (copy_to_user(optval, &info, len))
+ return -EFAULT;
+ return 0;
+ }
case TCP_QUICKACK:
val = !icsk->icsk_ack.pingpong;
break;
--
2.2.0.rc0.207.ga3a616c
--
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