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[src/trunk]: src/sys/netinet Minor changes: style, improve comments (and put ...
details: https://anonhg.NetBSD.org/src/rev/1747dc8b2590
branches: trunk
changeset: 831382:1747dc8b2590
user: maxv <maxv%NetBSD.org@localhost>
date: Wed Mar 28 13:50:14 2018 +0000
description:
Minor changes: style, improve comments (and put them at the correct place),
use NULL for pointers, and add {}s to prevent confusion.
diffstat:
sys/netinet/tcp_input.c | 246 ++++++++++++++++++++++++-----------------------
1 files changed, 127 insertions(+), 119 deletions(-)
diffs (truncated from 724 to 300 lines):
diff -r 0ccde89b12b8 -r 1747dc8b2590 sys/netinet/tcp_input.c
--- a/sys/netinet/tcp_input.c Wed Mar 28 06:48:55 2018 +0000
+++ b/sys/netinet/tcp_input.c Wed Mar 28 13:50:14 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: tcp_input.c,v 1.388 2018/03/23 09:30:55 maxv Exp $ */
+/* $NetBSD: tcp_input.c,v 1.389 2018/03/28 13:50:14 maxv Exp $ */
/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -148,7 +148,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tcp_input.c,v 1.388 2018/03/23 09:30:55 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tcp_input.c,v 1.389 2018/03/28 13:50:14 maxv Exp $");
#ifdef _KERNEL_OPT
#include "opt_inet.h"
@@ -458,10 +458,10 @@
TCP_REASS_LOCK_CHECK(tp);
/*
- * Call with th==0 after become established to
+ * Call with th==NULL after become established to
* force pre-ESTABLISHED data up to user socket.
*/
- if (th == 0)
+ if (th == NULL)
goto present;
m_claimm(m, &tcp_reass_mowner);
@@ -847,8 +847,7 @@
if (ip) {
in_print(src, sizeof(src), &ip->ip_src);
in_print(dst, sizeof(dst), &ip->ip_dst);
- }
- else {
+ } else {
strlcpy(src, "(unknown)", sizeof(src));
strlcpy(dst, "(unknown)", sizeof(dst));
}
@@ -868,8 +867,7 @@
if (ip6) {
in6_print(src, sizeof(src), &ip6->ip6_src);
in6_print(dst, sizeof(dst), &ip6->ip6_dst);
- }
- else {
+ } else {
strlcpy(src, "(unknown v6)", sizeof(src));
strlcpy(dst, "(unknown v6)", sizeof(dst));
}
@@ -990,16 +988,19 @@
return -1;
}
-/* When a packet arrives addressed to a vestigial tcpbp, we
+/*
+ * When a packet arrives addressed to a vestigial tcpbp, we
* nevertheless have to respond to it per the spec.
+ *
+ * This code is duplicated from the one in tcp_input().
*/
static void tcp_vtw_input(struct tcphdr *th, vestigial_inpcb_t *vp,
struct mbuf *m, int tlen)
{
- int tiflags;
- int todrop;
- uint32_t t_flags = 0;
- uint64_t *tcps;
+ int tiflags;
+ int todrop;
+ uint32_t t_flags = 0;
+ uint64_t *tcps;
tiflags = th->th_flags;
todrop = vp->rcv_nxt - th->th_seq;
@@ -1026,6 +1027,7 @@
if (tiflags & TH_RST)
goto drop;
tiflags &= ~(TH_FIN|TH_RST);
+
/*
* Send an ACK to resynchronize and drop any data.
* But keep on processing for RST or ACK.
@@ -1036,8 +1038,8 @@
tcps[TCP_STAT_RCVDUPPACK] += 1;
tcps[TCP_STAT_RCVDUPBYTE] += todrop;
TCP_STAT_PUTREF();
- } else if ((tiflags & TH_RST)
- && th->th_seq != vp->rcv_nxt) {
+ } else if ((tiflags & TH_RST) &&
+ th->th_seq != vp->rcv_nxt) {
/*
* Test for reset before adjusting the sequence
* number for overlapping data.
@@ -1077,7 +1079,7 @@
* If segment ends after window, drop trailing data
* (and PUSH and FIN); if nothing left, just ACK.
*/
- todrop = (th->th_seq + tlen) - (vp->rcv_nxt+vp->rcv_wnd);
+ todrop = (th->th_seq + tlen) - (vp->rcv_nxt + vp->rcv_wnd);
if (todrop > 0) {
TCP_STATINC(TCP_STAT_RCVPACKAFTERWIN);
@@ -1089,19 +1091,22 @@
* th->th_seq >= vp->rcv_nxt + vp->rcv_wnd
*/
TCP_STATADD(TCP_STAT_RCVBYTEAFTERWIN, tlen);
+
/*
* If a new connection request is received
* while in TIME_WAIT, drop the old connection
* and start over if the sequence numbers
* are above the previous ones.
*/
- if ((tiflags & TH_SYN)
- && SEQ_GT(th->th_seq, vp->rcv_nxt)) {
- /* We only support this in the !NOFDREF case, which
+ if ((tiflags & TH_SYN) &&
+ SEQ_GT(th->th_seq, vp->rcv_nxt)) {
+ /*
+ * We only support this in the !NOFDREF case, which
* is to say: not here.
*/
goto dropwithreset;
}
+
/*
* If window is closed can only take segments at
* window edge, and have to drop data and PUSH from
@@ -1112,10 +1117,12 @@
if (vp->rcv_wnd == 0 && th->th_seq == vp->rcv_nxt) {
t_flags |= TF_ACKNOW;
TCP_STATINC(TCP_STAT_RCVWINPROBE);
- } else
+ } else {
goto dropafterack;
- } else
+ }
+ } else {
TCP_STATADD(TCP_STAT_RCVBYTEAFTERWIN, todrop);
+ }
m_adj(m, -todrop);
tlen -= todrop;
tiflags &= ~(TH_PUSH|TH_FIN);
@@ -1161,15 +1168,14 @@
* We may want to rate-limit ACKs against SYN/RST attack.
*/
if (ppsratecheck(&tcp_ackdrop_ppslim_last, &tcp_ackdrop_ppslim_count,
- tcp_ackdrop_ppslim) == 0) {
+ tcp_ackdrop_ppslim) == 0) {
/* XXX stat */
goto drop;
}
/* ...fall into dropafterack2... */
dropafterack2:
- (void)tcp_respond(0, m, m, th, th->th_seq + tlen, th->th_ack,
- TH_ACK);
+ (void)tcp_respond(0, m, m, th, th->th_seq + tlen, th->th_ack, TH_ACK);
return;
dropwithreset:
@@ -1180,13 +1186,13 @@
if (tiflags & TH_RST)
goto drop;
- if (tiflags & TH_ACK)
+ if (tiflags & TH_ACK) {
tcp_respond(0, m, m, th, (tcp_seq)0, th->th_ack, TH_RST);
- else {
+ } else {
if (tiflags & TH_SYN)
++tlen;
(void)tcp_respond(0, m, m, th, th->th_seq + tlen, (tcp_seq)0,
- TH_RST|TH_ACK);
+ TH_RST|TH_ACK);
}
return;
drop:
@@ -1858,18 +1864,24 @@
}
/*
- * Header prediction: check for the two common cases
- * of a uni-directional data xfer. If the packet has
- * no control flags, is in-sequence, the window didn't
- * change and we're not retransmitting, it's a
- * candidate. If the length is zero and the ack moved
- * forward, we're the sender side of the xfer. Just
- * free the data acked & wake any higher level process
- * that was blocked waiting for space. If the length
- * is non-zero and the ack didn't move, we're the
- * receiver side. If we're getting packets in-order
- * (the reassembly queue is empty), add the data to
- * the socket buffer and note that we need a delayed ack.
+ * Fast path: check for the two common cases of a uni-directional
+ * data transfer. If:
+ * o We are in the ESTABLISHED state, and
+ * o The packet has no control flags, and
+ * o The packet is in-sequence, and
+ * o The window didn't change, and
+ * o We are not retransmitting
+ * It's a candidate.
+ *
+ * If the length (tlen) is zero and the ack moved forward, we're
+ * the sender side of the transfer. Just free the data acked and
+ * wake any higher level process that was blocked waiting for
+ * space.
+ *
+ * If the length is non-zero and the ack didn't move, we're the
+ * receiver side. If we're getting packets in-order (the reassembly
+ * queue is empty), add the data to the socket buffer and note
+ * that we need a delayed ack.
*/
if (tp->t_state == TCPS_ESTABLISHED &&
(tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ECE|TH_CWR|TH_ACK))
@@ -1888,8 +1900,7 @@
* note that we already know
* TSTMP_GEQ(opti.ts_val, tp->ts_recent)
*/
- if (opti.ts_present &&
- SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
+ if (opti.ts_present && SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
tp->ts_recent_age = tcp_now;
tp->ts_recent = opti.ts_val;
}
@@ -1949,7 +1960,7 @@
sowwakeup(so);
if (so->so_snd.sb_cc) {
KERNEL_LOCK(1, NULL);
- (void) tcp_output(tp);
+ (void)tcp_output(tp);
KERNEL_UNLOCK_ONE(NULL);
}
if (tcp_saveti)
@@ -1959,7 +1970,7 @@
} else if (th->th_ack == tp->snd_una &&
TAILQ_FIRST(&tp->segq) == NULL &&
tlen <= sbspace(&so->so_rcv)) {
- int newsize = 0; /* automatic sockbuf scaling */
+ int newsize = 0;
/*
* this is a pure, in-sequence data packet
@@ -2030,9 +2041,9 @@
* Drop TCP, IP headers and TCP options then add data
* to socket buffer.
*/
- if (so->so_state & SS_CANTRCVMORE)
+ if (so->so_state & SS_CANTRCVMORE) {
m_freem(m);
- else {
+ } else {
/*
* Set new socket buffer size.
* Give up when limit is reached.
@@ -2048,7 +2059,7 @@
tcp_setup_ack(tp, th);
if (tp->t_flags & TF_ACKNOW) {
KERNEL_LOCK(1, NULL);
- (void) tcp_output(tp);
+ (void)tcp_output(tp);
KERNEL_UNLOCK_ONE(NULL);
}
if (tcp_saveti)
@@ -2118,7 +2129,6 @@
tp->t_flags |= TF_ECN_PERMIT;
TCP_STATINC(TCP_STAT_ECN_SHS);
}
-
}
tp->irs = th->th_seq;
tcp_rcvseqinit(tp);
@@ -2169,8 +2179,9 @@
*/
if (tp->t_rtttime)
tcp_xmit_timer(tp, tcp_now - tp->t_rtttime);
- } else
+ } else {
tp->t_state = TCPS_SYN_RECEIVED;
+ }
/*
* Advance th->th_seq to correspond to first data byte.
@@ -2212,13 +2223,8 @@
tp->t_state != TCPS_SYN_SENT);
/*
- * First check timestamp, if present.
- * Then check that at least some bytes of segment are within
- * receive window. If segment begins before rcv_nxt,
- * drop leading data (and SYN); if nothing left, just ack.
- *
- * RFC 1323 PAWS: If we have a timestamp reply on this segment
- * and it's less than ts_recent, drop it.
+ * RFC1323 PAWS: if we have a timestamp reply on this segment and
+ * it's less than ts_recent, drop it.
*/
if (opti.ts_present && (tiflags & TH_RST) == 0 && tp->ts_recent &&
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