tcp: introduce TCP_SKB_CB(skb)->tcp_tw_isn

TCP_SKB_CB(skb)->when has different meaning in output and input paths.

In output path, it contains a timestamp.
In input path, it contains an ISN, chosen by tcp_timewait_state_process()

Lets add a different name to ease code comprehension.

Note that 'when' field will disappear in following patch,
as skb_mstamp already contains timestamp, the anonymous
union will promptly disappear as well.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 3 insertions, 3 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index aba4926ca095..9c8b9f1dcf69 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5906,7 +5906,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
         struct request_sock *req;
         struct tcp_sock *tp = tcp_sk(sk);
         struct dst_entry *dst = NULL;
-        __u32 isn = TCP_SKB_CB(skb)->when;
+        __u32 isn = TCP_SKB_CB(skb)->tcp_tw_isn;
         bool want_cookie = false, fastopen;
         struct flowi fl;
         struct tcp_fastopen_cookie foc = { .len = -1 };
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 487e2a41667f..02e6cd29ebf1 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1627,7 +1627,7 @@ int tcp_v4_rcv(struct sk_buff *skb)
         TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
                                     skb->len - th->doff * 4);
         TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
-        TCP_SKB_CB(skb)->when    = 0;
+        TCP_SKB_CB(skb)->tcp_tw_isn = 0;
         TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
         TCP_SKB_CB(skb)->sacked  = 0;
 
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 1649988bd1b6..a058f411d3a6 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -232,7 +232,7 @@ kill:
                 u32 isn = tcptw->tw_snd_nxt + 65535 + 2;
                 if (isn == 0)
                         isn++;
-                TCP_SKB_CB(skb)->when = isn;
+                TCP_SKB_CB(skb)->tcp_tw_isn = isn;
                 return TCP_TW_SYN;
         }