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tcp: introduce TCP_SKB_CB(skb)->tcp_tw_isn

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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>
This commit is contained in:
Eric Dumazet 2014-09-05 15:33:32 -07:00 committed by David S. Miller
parent 2ba38943ba
commit 04317dafd1
5 changed files with 11 additions and 6 deletions
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7
include/net/tcp.h
View file

@ -698,7 +698,12 @@ struct tcp_skb_cb {
} header; /* For incoming frames */
__u32 seq; /* Starting sequence number */
__u32 end_seq; /* SEQ + FIN + SYN + datalen */
__u32 when; /* used to compute rtt's */
union {
/* used in output path */
__u32 when; /* used to compute rtt's */
/* used in input path */
__u32 tcp_tw_isn; /* isn chosen by tcp_timewait_state_process() */
};
__u8 tcp_flags; /* TCP header flags. (tcp[13]) */
__u8 sacked; /* State flags for SACK/FACK. */

2
net/ipv4/tcp_input.c
View file

@ -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 };

2
net/ipv4/tcp_ipv4.c
View file

@ -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;

2
net/ipv4/tcp_minisocks.c
View file

@ -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;
}

4
net/ipv6/tcp_ipv6.c
View file

@ -738,7 +738,7 @@ static void tcp_v6_init_req(struct request_sock *req, struct sock *sk,
ipv6_addr_type(&ireq->ir_v6_rmt_addr) & IPV6_ADDR_LINKLOCAL)
ireq->ir_iif = inet6_iif(skb);
if (!TCP_SKB_CB(skb)->when &&
if (!TCP_SKB_CB(skb)->tcp_tw_isn &&
(ipv6_opt_accepted(sk, skb) || np->rxopt.bits.rxinfo ||
np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
np->rxopt.bits.rxohlim || np->repflow)) {
@ -1412,7 +1412,7 @@ static int tcp_v6_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 = ipv6_get_dsfield(hdr);
TCP_SKB_CB(skb)->sacked = 0;