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[TCP]: Move sack_ok access to obviously named funcs & cleanup
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Previously code had IsReno/IsFack defined as macros that were
local to tcp_input.c though sack_ok field has user elsewhere too
for the same purpose. This changes them to static inlines as
preferred according the current coding style and unifies the
access to sack_ok across multiple files. Magic bitops of sack_ok
for FACK and DSACK are also abstracted to functions with
appropriate names.

Note:
- One sack_ok = 1 remains but that's self explanary, i.e., it
  enables sack
- Couple of !IsReno cases are changed to tcp_is_sack
- There were no users for IsDSack => I dropped it

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored and David S. Miller committed Oct 10, 2007
1 parent b9c4595 commit e60402d
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Showing 6 changed files with 80 additions and 42 deletions.
28 changes: 28 additions & 0 deletions include/net/tcp.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -719,6 +719,34 @@ static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
icsk->icsk_ca_ops->cwnd_event(sk, event);
}

/* These functions determine how the current flow behaves in respect of SACK
* handling. SACK is negotiated with the peer, and therefore it can vary
* between different flows.
*
* tcp_is_sack - SACK enabled
* tcp_is_reno - No SACK
* tcp_is_fack - FACK enabled, implies SACK enabled
*/
static inline int tcp_is_sack(const struct tcp_sock *tp)
{
return tp->rx_opt.sack_ok;
}

static inline int tcp_is_reno(const struct tcp_sock *tp)
{
return !tcp_is_sack(tp);
}

static inline int tcp_is_fack(const struct tcp_sock *tp)
{
return tp->rx_opt.sack_ok & 2;
}

static inline void tcp_enable_fack(struct tcp_sock *tp)
{
tp->rx_opt.sack_ok |= 2;
}

static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
{
return tp->sacked_out + tp->lost_out;
Expand Down
2 changes: 1 addition & 1 deletion net/ipv4/tcp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2014,7 +2014,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)

if (tp->rx_opt.tstamp_ok)
info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
if (tp->rx_opt.sack_ok)
if (tcp_is_sack(tp))
info->tcpi_options |= TCPI_OPT_SACK;
if (tp->rx_opt.wscale_ok) {
info->tcpi_options |= TCPI_OPT_WSCALE;
Expand Down
82 changes: 46 additions & 36 deletions net/ipv4/tcp_input.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -111,10 +111,6 @@ int sysctl_tcp_abc __read_mostly;
#define FLAG_FORWARD_PROGRESS (FLAG_ACKED|FLAG_DATA_SACKED)
#define FLAG_ANY_PROGRESS (FLAG_FORWARD_PROGRESS|FLAG_SND_UNA_ADVANCED)

#define IsReno(tp) ((tp)->rx_opt.sack_ok == 0)
#define IsFack(tp) ((tp)->rx_opt.sack_ok & 2)
#define IsDSack(tp) ((tp)->rx_opt.sack_ok & 4)

#define IsSackFrto() (sysctl_tcp_frto == 0x2)

#define TCP_REMNANT (TCP_FLAG_FIN|TCP_FLAG_URG|TCP_FLAG_SYN|TCP_FLAG_PSH)
Expand Down Expand Up @@ -860,6 +856,21 @@ void tcp_enter_cwr(struct sock *sk, const int set_ssthresh)
}
}

/*
* Packet counting of FACK is based on in-order assumptions, therefore TCP
* disables it when reordering is detected
*/
static void tcp_disable_fack(struct tcp_sock *tp)
{
tp->rx_opt.sack_ok &= ~2;
}

/* Take a notice that peer is sending DSACKs */
static void tcp_dsack_seen(struct tcp_sock *tp)
{
tp->rx_opt.sack_ok |= 4;
}

/* Initialize metrics on socket. */

static void tcp_init_metrics(struct sock *sk)
Expand All @@ -881,7 +892,7 @@ static void tcp_init_metrics(struct sock *sk)
}
if (dst_metric(dst, RTAX_REORDERING) &&
tp->reordering != dst_metric(dst, RTAX_REORDERING)) {
tp->rx_opt.sack_ok &= ~2;
tcp_disable_fack(tp);
tp->reordering = dst_metric(dst, RTAX_REORDERING);
}

Expand Down Expand Up @@ -943,9 +954,9 @@ static void tcp_update_reordering(struct sock *sk, const int metric,
/* This exciting event is worth to be remembered. 8) */
if (ts)
NET_INC_STATS_BH(LINUX_MIB_TCPTSREORDER);
else if (IsReno(tp))
else if (tcp_is_reno(tp))
NET_INC_STATS_BH(LINUX_MIB_TCPRENOREORDER);
else if (IsFack(tp))
else if (tcp_is_fack(tp))
NET_INC_STATS_BH(LINUX_MIB_TCPFACKREORDER);
else
NET_INC_STATS_BH(LINUX_MIB_TCPSACKREORDER);
Expand All @@ -957,8 +968,7 @@ static void tcp_update_reordering(struct sock *sk, const int metric,
tp->sacked_out,
tp->undo_marker ? tp->undo_retrans : 0);
#endif
/* Disable FACK yet. */
tp->rx_opt.sack_ok &= ~2;
tcp_disable_fack(tp);
}
}

Expand Down Expand Up @@ -1020,7 +1030,7 @@ static int tcp_check_dsack(struct tcp_sock *tp, struct sk_buff *ack_skb,

if (before(start_seq_0, TCP_SKB_CB(ack_skb)->ack_seq)) {
dup_sack = 1;
tp->rx_opt.sack_ok |= 4;
tcp_dsack_seen(tp);
NET_INC_STATS_BH(LINUX_MIB_TCPDSACKRECV);
} else if (num_sacks > 1) {
u32 end_seq_1 = ntohl(get_unaligned(&sp[1].end_seq));
Expand All @@ -1029,7 +1039,7 @@ static int tcp_check_dsack(struct tcp_sock *tp, struct sk_buff *ack_skb,
if (!after(end_seq_0, end_seq_1) &&
!before(start_seq_0, start_seq_1)) {
dup_sack = 1;
tp->rx_opt.sack_ok |= 4;
tcp_dsack_seen(tp);
NET_INC_STATS_BH(LINUX_MIB_TCPDSACKOFORECV);
}
}
Expand Down Expand Up @@ -1326,7 +1336,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
continue;
if ((TCP_SKB_CB(skb)->sacked&TCPCB_SACKED_RETRANS) &&
after(lost_retrans, TCP_SKB_CB(skb)->ack_seq) &&
(IsFack(tp) ||
(tcp_is_fack(tp) ||
!before(lost_retrans,
TCP_SKB_CB(skb)->ack_seq + tp->reordering *
tp->mss_cache))) {
Expand Down Expand Up @@ -1526,7 +1536,7 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag)

tp->lost_out = 0;
tp->retrans_out = 0;
if (IsReno(tp))
if (tcp_is_reno(tp))
tcp_reset_reno_sack(tp);

tcp_for_write_queue(skb, sk) {
Expand Down Expand Up @@ -1668,7 +1678,7 @@ static int tcp_check_sack_reneging(struct sock *sk)

static inline int tcp_fackets_out(struct tcp_sock *tp)
{
return IsReno(tp) ? tp->sacked_out+1 : tp->fackets_out;
return tcp_is_reno(tp) ? tp->sacked_out+1 : tp->fackets_out;
}

static inline int tcp_skb_timedout(struct sock *sk, struct sk_buff *skb)
Expand Down Expand Up @@ -1872,7 +1882,7 @@ static void tcp_update_scoreboard(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);

if (IsFack(tp)) {
if (tcp_is_fack(tp)) {
int lost = tp->fackets_out - tp->reordering;
if (lost <= 0)
lost = 1;
Expand All @@ -1886,7 +1896,7 @@ static void tcp_update_scoreboard(struct sock *sk)
* Hence, we can detect timed out packets during fast
* retransmit without falling to slow start.
*/
if (!IsReno(tp) && tcp_head_timedout(sk)) {
if (!tcp_is_reno(tp) && tcp_head_timedout(sk)) {
struct sk_buff *skb;

skb = tp->scoreboard_skb_hint ? tp->scoreboard_skb_hint
Expand Down Expand Up @@ -1938,7 +1948,7 @@ static void tcp_cwnd_down(struct sock *sk, int flag)
int decr = tp->snd_cwnd_cnt + 1;

if ((flag&(FLAG_ANY_PROGRESS|FLAG_DSACKING_ACK)) ||
(IsReno(tp) && !(flag&FLAG_NOT_DUP))) {
(tcp_is_reno(tp) && !(flag&FLAG_NOT_DUP))) {
tp->snd_cwnd_cnt = decr&1;
decr >>= 1;

Expand Down Expand Up @@ -2029,7 +2039,7 @@ static int tcp_try_undo_recovery(struct sock *sk)
NET_INC_STATS_BH(LINUX_MIB_TCPFULLUNDO);
tp->undo_marker = 0;
}
if (tp->snd_una == tp->high_seq && IsReno(tp)) {
if (tp->snd_una == tp->high_seq && tcp_is_reno(tp)) {
/* Hold old state until something *above* high_seq
* is ACKed. For Reno it is MUST to prevent false
* fast retransmits (RFC2582). SACK TCP is safe. */
Expand Down Expand Up @@ -2059,7 +2069,7 @@ static int tcp_try_undo_partial(struct sock *sk, int acked)
{
struct tcp_sock *tp = tcp_sk(sk);
/* Partial ACK arrived. Force Hoe's retransmit. */
int failed = IsReno(tp) || tp->fackets_out>tp->reordering;
int failed = tcp_is_reno(tp) || tp->fackets_out>tp->reordering;

if (tcp_may_undo(tp)) {
/* Plain luck! Hole if filled with delayed
Expand Down Expand Up @@ -2104,7 +2114,7 @@ static int tcp_try_undo_loss(struct sock *sk)
NET_INC_STATS_BH(LINUX_MIB_TCPLOSSUNDO);
inet_csk(sk)->icsk_retransmits = 0;
tp->undo_marker = 0;
if (!IsReno(tp))
if (tcp_is_sack(tp))
tcp_set_ca_state(sk, TCP_CA_Open);
return 1;
}
Expand Down Expand Up @@ -2251,14 +2261,14 @@ tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag)
if (!tp->undo_marker ||
/* For SACK case do not Open to allow to undo
* catching for all duplicate ACKs. */
IsReno(tp) || tp->snd_una != tp->high_seq) {
tcp_is_reno(tp) || tp->snd_una != tp->high_seq) {
tp->undo_marker = 0;
tcp_set_ca_state(sk, TCP_CA_Open);
}
break;

case TCP_CA_Recovery:
if (IsReno(tp))
if (tcp_is_reno(tp))
tcp_reset_reno_sack(tp);
if (tcp_try_undo_recovery(sk))
return;
Expand All @@ -2271,7 +2281,7 @@ tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag)
switch (icsk->icsk_ca_state) {
case TCP_CA_Recovery:
if (!(flag & FLAG_SND_UNA_ADVANCED)) {
if (IsReno(tp) && is_dupack)
if (tcp_is_reno(tp) && is_dupack)
tcp_add_reno_sack(sk);
} else
do_lost = tcp_try_undo_partial(sk, pkts_acked);
Expand All @@ -2288,7 +2298,7 @@ tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag)
return;
/* Loss is undone; fall through to processing in Open state. */
default:
if (IsReno(tp)) {
if (tcp_is_reno(tp)) {
if (flag & FLAG_SND_UNA_ADVANCED)
tcp_reset_reno_sack(tp);
if (is_dupack)
Expand Down Expand Up @@ -2316,7 +2326,7 @@ tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag)

/* Otherwise enter Recovery state */

if (IsReno(tp))
if (tcp_is_reno(tp))
NET_INC_STATS_BH(LINUX_MIB_TCPRENORECOVERY);
else
NET_INC_STATS_BH(LINUX_MIB_TCPSACKRECOVERY);
Expand Down Expand Up @@ -2573,7 +2583,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
tcp_ack_update_rtt(sk, acked, seq_rtt);
tcp_ack_packets_out(sk);

if (IsReno(tp))
if (tcp_is_reno(tp))
tcp_remove_reno_sacks(sk, pkts_acked);

if (ca_ops->pkts_acked) {
Expand All @@ -2599,7 +2609,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
BUG_TRAP((int)tp->sacked_out >= 0);
BUG_TRAP((int)tp->lost_out >= 0);
BUG_TRAP((int)tp->retrans_out >= 0);
if (!tp->packets_out && tp->rx_opt.sack_ok) {
if (!tp->packets_out && tcp_is_sack(tp)) {
const struct inet_connection_sock *icsk = inet_csk(sk);
if (tp->lost_out) {
printk(KERN_DEBUG "Leak l=%u %d\n",
Expand Down Expand Up @@ -2779,7 +2789,7 @@ static int tcp_process_frto(struct sock *sk, int flag)
return 1;
}

if (!IsSackFrto() || IsReno(tp)) {
if (!IsSackFrto() || tcp_is_reno(tp)) {
/* RFC4138 shortcoming in step 2; should also have case c):
* ACK isn't duplicate nor advances window, e.g., opposite dir
* data, winupdate
Expand Down Expand Up @@ -3263,7 +3273,7 @@ static void tcp_fin(struct sk_buff *skb, struct sock *sk, struct tcphdr *th)
* Probably, we should reset in this case. For now drop them.
*/
__skb_queue_purge(&tp->out_of_order_queue);
if (tp->rx_opt.sack_ok)
if (tcp_is_sack(tp))
tcp_sack_reset(&tp->rx_opt);
sk_stream_mem_reclaim(sk);

Expand Down Expand Up @@ -3293,7 +3303,7 @@ static inline int tcp_sack_extend(struct tcp_sack_block *sp, u32 seq, u32 end_se

static void tcp_dsack_set(struct tcp_sock *tp, u32 seq, u32 end_seq)
{
if (tp->rx_opt.sack_ok && sysctl_tcp_dsack) {
if (tcp_is_sack(tp) && sysctl_tcp_dsack) {
if (before(seq, tp->rcv_nxt))
NET_INC_STATS_BH(LINUX_MIB_TCPDSACKOLDSENT);
else
Expand Down Expand Up @@ -3323,7 +3333,7 @@ static void tcp_send_dupack(struct sock *sk, struct sk_buff *skb)
NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKLOST);
tcp_enter_quickack_mode(sk);

if (tp->rx_opt.sack_ok && sysctl_tcp_dsack) {
if (tcp_is_sack(tp) && sysctl_tcp_dsack) {
u32 end_seq = TCP_SKB_CB(skb)->end_seq;

if (after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt))
Expand Down Expand Up @@ -3639,7 +3649,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)

if (!skb_peek(&tp->out_of_order_queue)) {
/* Initial out of order segment, build 1 SACK. */
if (tp->rx_opt.sack_ok) {
if (tcp_is_sack(tp)) {
tp->rx_opt.num_sacks = 1;
tp->rx_opt.dsack = 0;
tp->rx_opt.eff_sacks = 1;
Expand Down Expand Up @@ -3704,7 +3714,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
}

add_sack:
if (tp->rx_opt.sack_ok)
if (tcp_is_sack(tp))
tcp_sack_new_ofo_skb(sk, seq, end_seq);
}
}
Expand Down Expand Up @@ -3893,7 +3903,7 @@ static int tcp_prune_queue(struct sock *sk)
* is in a sad state like this, we care only about integrity
* of the connection not performance.
*/
if (tp->rx_opt.sack_ok)
if (tcp_is_sack(tp))
tcp_sack_reset(&tp->rx_opt);
sk_stream_mem_reclaim(sk);
}
Expand Down Expand Up @@ -4594,8 +4604,8 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
tp->tcp_header_len = sizeof(struct tcphdr);
}

if (tp->rx_opt.sack_ok && sysctl_tcp_fack)
tp->rx_opt.sack_ok |= 2;
if (tcp_is_sack(tp) && sysctl_tcp_fack)
tcp_enable_fack(tp);

tcp_mtup_init(sk);
tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
Expand Down
2 changes: 1 addition & 1 deletion net/ipv4/tcp_minisocks.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -445,7 +445,7 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req,
newtp->rx_opt.tstamp_ok = ireq->tstamp_ok;
if ((newtp->rx_opt.sack_ok = ireq->sack_ok) != 0) {
if (sysctl_tcp_fack)
newtp->rx_opt.sack_ok |= 2;
tcp_enable_fack(newtp);
}
newtp->window_clamp = req->window_clamp;
newtp->rcv_ssthresh = req->rcv_wnd;
Expand Down
6 changes: 3 additions & 3 deletions net/ipv4/tcp_output.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -737,7 +737,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, unsigned int mss

if (diff > 0) {
/* Adjust Reno SACK estimate. */
if (!tp->rx_opt.sack_ok) {
if (tcp_is_reno(tp)) {
tcp_dec_pcount_approx_int(&tp->sacked_out, diff);
tcp_verify_left_out(tp);
}
Expand Down Expand Up @@ -1728,7 +1728,7 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, int m
if (TCP_SKB_CB(next_skb)->sacked&TCPCB_LOST)
tp->lost_out -= tcp_skb_pcount(next_skb);
/* Reno case is special. Sigh... */
if (!tp->rx_opt.sack_ok && tp->sacked_out)
if (tcp_is_reno(tp) && tp->sacked_out)
tcp_dec_pcount_approx(&tp->sacked_out, next_skb);

/* Not quite right: it can be > snd.fack, but
Expand Down Expand Up @@ -1976,7 +1976,7 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
return;

/* No forward retransmissions in Reno are possible. */
if (!tp->rx_opt.sack_ok)
if (tcp_is_reno(tp))
return;

/* Yeah, we have to make difficult choice between forward transmission
Expand Down
2 changes: 1 addition & 1 deletion net/ipv4/tcp_timer.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -315,7 +315,7 @@ static void tcp_retransmit_timer(struct sock *sk)
if (icsk->icsk_retransmits == 0) {
if (icsk->icsk_ca_state == TCP_CA_Disorder ||
icsk->icsk_ca_state == TCP_CA_Recovery) {
if (tp->rx_opt.sack_ok) {
if (tcp_is_sack(tp)) {
if (icsk->icsk_ca_state == TCP_CA_Recovery)
NET_INC_STATS_BH(LINUX_MIB_TCPSACKRECOVERYFAIL);
else
Expand Down

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