tcp: add data bytes retransmitted stats

Introduce a new TCP stat to record the number of bytes retransmitted
(RFC4898 tcpEStatsPerfOctetsRetrans) and expose it in both tcp_info
(TCP_INFO) and opt_stats (SOF_TIMESTAMPING_OPT_STATS).

Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 873cb9968ff5..5ed1be88e922 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2595,6 +2595,7 @@ int tcp_disconnect(struct sock *sk, int flags)
         tcp_saved_syn_free(tp);
         tp->compressed_ack = 0;
         tp->bytes_sent = 0;
+        tp->bytes_retrans = 0;
 
         /* Clean up fastopen related fields */
         tcp_free_fastopen_req(tp);
@@ -3203,6 +3204,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
         info->tcpi_delivered = tp->delivered;
         info->tcpi_delivered_ce = tp->delivered_ce;
         info->tcpi_bytes_sent = tp->bytes_sent;
+        info->tcpi_bytes_retrans = tp->bytes_retrans;
         unlock_sock_fast(sk, slow);
 }
 EXPORT_SYMBOL_GPL(tcp_get_info);
@@ -3228,6 +3230,7 @@ static size_t tcp_opt_stats_get_size(void)
                 nla_total_size(sizeof(u32)) + /* TCP_NLA_DELIVERED */
                 nla_total_size(sizeof(u32)) + /* TCP_NLA_DELIVERED_CE */
                 nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_SENT */
+                nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_RETRANS */
                 0;
 }
 
@@ -3277,6 +3280,8 @@ struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk)
 
         nla_put_u64_64bit(stats, TCP_NLA_BYTES_SENT, tp->bytes_sent,
                           TCP_NLA_PAD);
+        nla_put_u64_64bit(stats, TCP_NLA_BYTES_RETRANS, tp->bytes_retrans,
+                          TCP_NLA_PAD);
 
         return stats;
 }