-/* tcp_input.c 1.14 81/10/31 */
+/* tcp_input.c 1.68 82/06/20 */
#include "../h/param.h"
#include "../h/systm.h"
#include "../h/mbuf.h"
+#include "../h/protosw.h"
#include "../h/socket.h"
-#include "../inet/inet.h"
-#include "../inet/inet_systm.h"
-#include "../inet/imp.h"
-#include "../inet/inet_host.h"
-#include "../inet/ip.h"
-#include "../inet/tcp.h"
-#include "../inet/tcp_fsm.h"
-
+#include "../h/socketvar.h"
+#include "../net/in.h"
+#include "../net/route.h"
+#include "../net/in_pcb.h"
+#include "../net/in_systm.h"
+#include "../net/if.h"
+#include "../net/ip.h"
+#include "../net/ip_var.h"
+#include "../net/tcp.h"
+#include "../net/tcp_fsm.h"
+#include "../net/tcp_seq.h"
+#include "../net/tcp_timer.h"
+#include "../net/tcp_var.h"
+#include "../net/tcpip.h"
+#include "../net/tcp_debug.h"
+#include "../errno.h"
+
+int tcpprintfs = 0;
int tcpcksum = 1;
-
-tcp_input(mp)
- register struct mbuf *mp;
+struct sockaddr_in tcp_in = { AF_INET };
+struct tcpiphdr tcp_saveti;
+extern tcpnodelack;
+
+struct tcpcb *tcp_newtcpcb();
+/*
+ * TCP input routine, follows pages 65-76 of the
+ * protocol specification dated September, 1981 very closely.
+ */
+tcp_input(m0)
+ struct mbuf *m0;
{
- register struct th *n; /* known to be r10 */
- register int j; /* known to be r9 */
- register struct tcb *tp;
- int nstate;
- struct mbuf *m;
- struct ucb *up;
- int hlen, tlen;
- u_short lport, fport;
-#ifdef TCPDEBUG
- struct tcp_debug tdb;
-#endif
-COUNT(TCP_INPUT);
+ register struct tcpiphdr *ti;
+ struct inpcb *inp;
+ register struct mbuf *m;
+ struct mbuf *om = 0;
+ int len, tlen, off;
+ register struct tcpcb *tp = 0;
+ register int tiflags;
+ struct socket *so;
+ int todrop, acked;
+ short ostate;
+ struct in_addr laddr;
/*
- * Build extended tcp header
+ * Get IP and TCP header together in first mbuf.
+ * Note: IP leaves IP header in first mbuf.
*/
- n = (struct th *)((int)mp + mp->m_off);
- tlen = ((struct ip *)n)->ip_len;
- n->t_len = htons(tlen);
- n->t_next = NULL;
- n->t_prev = NULL;
- n->t_x1 = 0;
- lport = ntohs(n->t_dst);
- fport = ntohs(n->t_src);
-
- /* WONT BE POSSIBLE WHEN MBUFS ARE 256 BYTES */
- if ((hlen = n->t_off << 2) > mp->m_len)
- { printf("tcp header overflow\n"); m_freem(mp); return; }
+ m = m0;
+ ti = mtod(m, struct tcpiphdr *);
+ if (((struct ip *)ti)->ip_hl > (sizeof (struct ip) >> 2))
+ ip_stripoptions((struct ip *)ti, (struct mbuf *)0);
+ if (m->m_off > MMAXOFF || m->m_len < sizeof (struct tcpiphdr)) {
+ if ((m = m_pullup(m, sizeof (struct tcpiphdr))) == 0) {
+ tcpstat.tcps_hdrops++;
+ return;
+ }
+ ti = mtod(m, struct tcpiphdr *);
+ }
+ /*
+ * Checksum extended TCP header and data.
+ */
+ tlen = ((struct ip *)ti)->ip_len;
+ len = sizeof (struct ip) + tlen;
if (tcpcksum) {
- /*
- * Checksum extended header and data
- */
- j = n->t_sum; n->t_sum = 0;
-#ifdef vax
- if (tlen == 20) {
- asm("addl3 $8,r10,r0; movl (r0)+,r1; addl2 (r0)+,r1");
- asm("adwc (r0)+,r1; adwc (r0)+,r1; adwc (r0)+,r1");
- asm("adwc (r0)+,r1; adwc (r0)+,r1; adwc (r0)+,r1");
- asm("adwc $0,r1; ashl $-16,r1,r0; addw2 r0,r1");
- asm("adwc $0,r1"); /* ### */
- asm("mcoml r1,r1; movzwl r1,r1; subl2 r1,r9");
- } else
+ ti->ti_next = ti->ti_prev = 0;
+ ti->ti_x1 = 0;
+ ti->ti_len = (u_short)tlen;
+#if vax || pdp11
+ ti->ti_len = htons((u_short)ti->ti_len);
#endif
- j -= cksum(mp, sizeof (struct ip) + tlen);
- if (j != 0) {
- netstat.t_badsum++;
- m_freem(mp);
- return;
+ if (ti->ti_sum = in_cksum(m, len)) {
+ tcpstat.tcps_badsum++;
+ if (tcpprintfs)
+ printf("tcp cksum %x\n", ti->ti_sum);
+ goto drop;
}
}
/*
- * Find tcb for message (SHOULDN'T USE LINEAR SEARCH!)
+ * Check that TCP offset makes sense,
+ * pull out TCP options and adjust length.
*/
- for (tp = tcb.tcb_next; tp != (struct tcb *)&tcb; tp = tp->tcb_next)
- if (tp->t_lport == lport && tp->t_fport == fport &&
- tp->t_ucb->uc_host->h_addr.s_addr == n->t_s.s_addr)
- goto found;
- for (tp = tcb.tcb_next; tp != (struct tcb *)&tcb; tp = tp->tcb_next)
- if (tp->t_lport == lport &&
- (tp->t_fport==fport || tp->t_fport==0) &&
- (tp->t_ucb->uc_host->h_addr.s_addr == n->t_s.s_addr ||
- tp->t_ucb->uc_host->h_addr.s_addr == 0))
- goto found;
- goto notwanted;
-found:
+ off = ti->ti_off << 2;
+ if (off < sizeof (struct tcphdr) || off > tlen) {
+ tcpstat.tcps_badoff++;
+ goto drop;
+ }
+ tlen -= off;
+ ti->ti_len = tlen;
+ if (off > sizeof (struct tcphdr)) {
+ if ((m = m_pullup(m, sizeof (struct ip) + off)) == 0) {
+ tcpstat.tcps_hdrops++;
+ goto drop;
+ }
+ ti = mtod(m, struct tcpiphdr *);
+ om = m_get(M_DONTWAIT);
+ if (om == 0)
+ goto drop;
+ om->m_off = MMINOFF;
+ om->m_len = off - sizeof (struct tcphdr);
+ { caddr_t op = mtod(m, caddr_t) + sizeof (struct tcpiphdr);
+ bcopy(op, mtod(om, caddr_t), (unsigned)om->m_len);
+ m->m_len -= om->m_len;
+ bcopy(op+om->m_len, op,
+ (unsigned)(m->m_len-sizeof (struct tcpiphdr)));
+ }
+ }
+ tiflags = ti->ti_flags;
+
+ /*
+ * Drop TCP and IP headers.
+ */
+ off += sizeof (struct ip);
+ m->m_off += off;
+ m->m_len -= off;
+#if vax || pdp11
/*
- * Byte swap header
+ * Convert TCP protocol specific fields to host format.
*/
- n->t_len = tlen - hlen;
- n->t_src = fport;
- n->t_dst = lport;
- n->t_seq = ntohl(n->t_seq);
- n->t_ackno = ntohl(n->t_ackno);
- n->t_win = ntohs(n->t_win);
- n->t_urp = ntohs(n->t_urp);
+ ti->ti_seq = ntohl(ti->ti_seq);
+ ti->ti_ack = ntohl(ti->ti_ack);
+ ti->ti_win = ntohs(ti->ti_win);
+ ti->ti_urp = ntohs(ti->ti_urp);
+#endif
+
+ /*
+ * Locate pcb for segment. On match, update the local
+ * address stored in the block to reflect anchoring.
+ */
+ inp = in_pcblookup
+ (&tcb, ti->ti_src, ti->ti_sport, ti->ti_dst, ti->ti_dport,
+ INPLOOKUP_WILDCARD);
/*
- * Check segment seq # and do rst processing
+ * If the state is CLOSED (i.e., TCB does not exist) then
+ * all data in the incoming segment is discarded.
*/
+ if (inp == 0)
+ goto dropwithreset;
+ tp = intotcpcb(inp);
+ if (tp == 0)
+ goto dropwithreset;
+ so = inp->inp_socket;
+ if (so->so_options & SO_DEBUG) {
+ ostate = tp->t_state;
+ tcp_saveti = *ti;
+ }
+
+ /*
+ * Segment received on connection.
+ * Reset idle time and keep-alive timer.
+ */
+ tp->t_idle = 0;
+ tp->t_timer[TCPT_KEEP] = TCPTV_KEEP;
+
+ /*
+ * Process options.
+ */
+ if (om) {
+ tcp_dooptions(tp, om);
+ om = 0;
+ }
+
+ /*
+ * Calculate amount of space in receive window,
+ * and then do TCP input processing.
+ */
+ tp->rcv_wnd = sbspace(&so->so_rcv);
+ if (tp->rcv_wnd < 0)
+ tp->rcv_wnd = 0;
+
switch (tp->t_state) {
- case LISTEN:
- if ((n->th_flags&TH_ACK) || !syn_ok(tp, n)) {
- tcp_sndrst(tp, n);
- goto badseg;
- }
- if (n->th_flags&TH_RST)
- goto badseg;
- goto goodseg;
-
- case SYN_SENT:
- if (!ack_ok(tp, n) || !syn_ok(tp, n)) {
- tcp_sndrst(tp, n); /* 71,72,75 */
- goto badseg;
+ /*
+ * If the state is LISTEN then ignore segment if it contains an RST.
+ * If the segment contains an ACK then it is bad and send a RST.
+ * If it does not contain a SYN then it is not interesting; drop it.
+ * Otherwise initialize tp->rcv_nxt, and tp->irs, select an initial
+ * tp->iss, and send a segment:
+ * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK>
+ * Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss.
+ * Fill in remote peer address fields if not previously specified.
+ * Enter SYN_RECEIVED state, and process any other fields of this
+ * segment in this state.
+ */
+ case TCPS_LISTEN:
+ if (tiflags & TH_RST)
+ goto drop;
+ if (tiflags & TH_ACK)
+ goto dropwithreset;
+ if ((tiflags & TH_SYN) == 0)
+ goto drop;
+ tcp_in.sin_addr = ti->ti_src;
+ tcp_in.sin_port = ti->ti_sport;
+ laddr = inp->inp_laddr;
+ if (inp->inp_laddr.s_addr == 0)
+ inp->inp_laddr = ti->ti_dst;
+ if (in_pcbconnect(inp, (struct sockaddr_in *)&tcp_in)) {
+ inp->inp_laddr = laddr;
+ goto drop;
}
- if (n->th_flags&TH_RST) {
- tcp_close(tp, URESET); /* 70 */
- tp->t_state = CLOSED;
- goto badseg;
+ tp->t_template = tcp_template(tp);
+ if (tp->t_template == 0) {
+ in_pcbdisconnect(inp);
+ inp->inp_laddr = laddr;
+ tp = 0;
+ goto drop;
}
- goto goodseg;
-
- default:
- if ((n->th_flags&TH_RST) == 0)
- goto common;
- if (n->t_seq < tp->rcv_nxt) /* bad rst */
- goto badseg; /* 69 */
- switch (tp->t_state) {
+ tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2;
+ tp->irs = ti->ti_seq;
+ tcp_sendseqinit(tp);
+ tcp_rcvseqinit(tp);
+ tp->t_state = TCPS_SYN_RECEIVED;
+ tp->t_timer[TCPT_KEEP] = TCPTV_KEEP;
+ goto trimthenstep6;
- case L_SYN_RCVD:
- if (ack_ok(tp, n) == 0)
- goto badseg; /* 69 */
- tp->t_rexmt = 0;
- tp->t_rexmttl = 0;
- tp->t_persist = 0;
- h_free(tp->t_ucb->uc_host);
- tp->t_state = LISTEN;
- goto badseg;
+ /*
+ * If the state is SYN_SENT:
+ * if seg contains an ACK, but not for our SYN, drop the input.
+ * if seg contains a RST, then drop the connection.
+ * if seg does not contain SYN, then drop it.
+ * Otherwise this is an acceptable SYN segment
+ * initialize tp->rcv_nxt and tp->irs
+ * if seg contains ack then advance tp->snd_una
+ * if SYN has been acked change to ESTABLISHED else SYN_RCVD state
+ * arrange for segment to be acked (eventually)
+ * continue processing rest of data/controls, beginning with URG
+ */
+ case TCPS_SYN_SENT:
+ if ((tiflags & TH_ACK) &&
+/* this should be SEQ_LT; is SEQ_LEQ for BBN vax TCP only */
+ (SEQ_LT(ti->ti_ack, tp->iss) ||
+ SEQ_GT(ti->ti_ack, tp->snd_max)))
+ goto dropwithreset;
+ if (tiflags & TH_RST) {
+ if (tiflags & TH_ACK) {
+ tcp_drop(tp, ECONNREFUSED);
+ tp = 0;
+ }
+ goto drop;
+ }
+ if ((tiflags & TH_SYN) == 0)
+ goto drop;
+ tp->snd_una = ti->ti_ack;
+ if (SEQ_LT(tp->snd_nxt, tp->snd_una))
+ tp->snd_nxt = tp->snd_una;
+ tp->t_timer[TCPT_REXMT] = 0;
+ tp->irs = ti->ti_seq;
+ tcp_rcvseqinit(tp);
+ tp->t_flags |= TF_ACKNOW;
+ if (SEQ_GT(tp->snd_una, tp->iss)) {
+ if (so->so_options & SO_ACCEPTCONN)
+ so->so_state |= SS_CONNAWAITING;
+ soisconnected(so);
+ tp->t_state = TCPS_ESTABLISHED;
+ (void) tcp_reass(tp, (struct tcpiphdr *)0);
+ } else
+ tp->t_state = TCPS_SYN_RECEIVED;
+ goto trimthenstep6;
- default:
- tcp_close(tp, URESET); /* 66 */
- tp->t_state = CLOSED;
- goto badseg;
+trimthenstep6:
+ /*
+ * Advance ti->ti_seq to correspond to first data byte.
+ * If data, trim to stay within window,
+ * dropping FIN if necessary.
+ */
+ ti->ti_seq++;
+ if (ti->ti_len > tp->rcv_wnd) {
+ todrop = ti->ti_len - tp->rcv_wnd;
+ m_adj(m, -todrop);
+ ti->ti_len = tp->rcv_wnd;
+ ti->ti_flags &= ~TH_FIN;
}
- /*NOTREACHED*/
+ tp->snd_wl1 = ti->ti_seq - 1;
+ goto step6;
+ }
- case SYN_RCVD:
-common:
- if (ack_ok(tp, n) == 0) {
- tcp_sndrst(tp, n); /* 74 */
- goto badseg;
+ /*
+ * States other than LISTEN or SYN_SENT.
+ * First check that at least some bytes of segment are within
+ * receive window.
+ */
+ if (tp->rcv_wnd == 0) {
+ /*
+ * If window is closed can only take segments at
+ * window edge, and have to drop data and PUSH from
+ * incoming segments.
+ */
+ if (tp->rcv_nxt != ti->ti_seq)
+ goto dropafterack;
+ if (ti->ti_len > 0) {
+ m_adj(m, ti->ti_len);
+ ti->ti_len = 0;
+ ti->ti_flags &= ~(TH_PUSH|TH_FIN);
}
- if (syn_ok(tp, n) && n->t_seq != tp->irs) {
- tcp_sndnull(tp); /* 74 */
- goto badseg;
+ } else {
+ /*
+ * If segment begins before rcv_nxt, drop leading
+ * data (and SYN); if nothing left, just ack.
+ */
+ todrop = tp->rcv_nxt - ti->ti_seq;
+ if (todrop > 0) {
+ if (tiflags & TH_SYN) {
+ tiflags &= ~TH_SYN;
+ ti->ti_flags &= ~TH_SYN;
+ ti->ti_seq++;
+ if (ti->ti_urp > 1)
+ ti->ti_urp--;
+ else
+ tiflags &= ~TH_URG;
+ todrop--;
+ }
+ if (todrop > ti->ti_len ||
+ todrop == ti->ti_len && (tiflags&TH_FIN) == 0)
+ goto dropafterack;
+ m_adj(m, todrop);
+ ti->ti_seq += todrop;
+ ti->ti_len -= todrop;
+ if (ti->ti_urp > todrop)
+ ti->ti_urp -= todrop;
+ else {
+ tiflags &= ~TH_URG;
+ ti->ti_flags &= ~TH_URG;
+ ti->ti_urp = 0;
+ }
+ }
+ /*
+ * If segment ends after window, drop trailing data
+ * (and PUSH and FIN); if nothing left, just ACK.
+ */
+ todrop = (ti->ti_seq+ti->ti_len) - (tp->rcv_nxt+tp->rcv_wnd);
+ if (todrop > 0) {
+ if (todrop >= ti->ti_len)
+ goto dropafterack;
+ m_adj(m, -todrop);
+ ti->ti_len -= todrop;
+ ti->ti_flags &= ~(TH_PUSH|TH_FIN);
}
- goto goodseg;
}
-badseg:
- m_freem(mp);
- return;
-goodseg:
-#ifdef notdef
- /* DO SOMETHING ABOUT UNACK!!! */
/*
- * Defer processing if no buffer space for this connection.
+ * If a segment is received on a connection after the
+ * user processes are gone, then RST the other end.
*/
- up = tp->t_ucb;
- if (up->uc_rcc > up->uc_rhiwat &&
- && n->t_len != 0 && mbstat.m_bufs < mbstat.m_lowat) {
- mp->m_act = (struct mbuf *)0;
- if ((m = tp->t_rcv_unack) != NULL) {
- while (m->m_act != NULL)
- m = m->m_act;
- m->m_act = mp;
- } else
- tp->t_rcv_unack = mp;
- return;
+ if (so->so_state & SS_USERGONE) {
+ tcp_close(tp);
+ tp = 0;
+ goto dropwithreset;
}
-#endif
/*
- * Discard ip header, and do tcp input processing.
+ * If the RST bit is set examine the state:
+ * SYN_RECEIVED STATE:
+ * If passive open, return to LISTEN state.
+ * If active open, inform user that connection was refused.
+ * ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES:
+ * Inform user that connection was reset, and close tcb.
+ * CLOSING, LAST_ACK, TIME_WAIT STATES
+ * Close the tcb.
+ */
+ if (tiflags&TH_RST) switch (tp->t_state) {
+
+ case TCPS_SYN_RECEIVED:
+ if (inp->inp_socket->so_options & SO_ACCEPTCONN) {
+ /* a miniature tcp_close, but invisible to user */
+ (void) m_free(dtom(tp->t_template));
+ (void) m_free(dtom(tp));
+ inp->inp_ppcb = 0;
+ tp = tcp_newtcpcb(inp);
+ tp->t_state = TCPS_LISTEN;
+ inp->inp_faddr.s_addr = 0;
+ inp->inp_fport = 0;
+ inp->inp_laddr.s_addr = 0; /* not quite right */
+ tp = 0;
+ goto drop;
+ }
+ tcp_drop(tp, ECONNREFUSED);
+ tp = 0;
+ goto drop;
+
+ case TCPS_ESTABLISHED:
+ case TCPS_FIN_WAIT_1:
+ case TCPS_FIN_WAIT_2:
+ case TCPS_CLOSE_WAIT:
+ tcp_drop(tp, ECONNRESET);
+ tp = 0;
+ goto drop;
+
+ case TCPS_CLOSING:
+ case TCPS_LAST_ACK:
+ case TCPS_TIME_WAIT:
+ tcp_close(tp);
+ tp = 0;
+ goto drop;
+ }
+
+ /*
+ * If a SYN is in the window, then this is an
+ * error and we send an RST and drop the connection.
+ */
+ if (tiflags & TH_SYN) {
+ tcp_drop(tp, ECONNRESET);
+ tp = 0;
+ goto dropwithreset;
+ }
+
+ /*
+ * If the ACK bit is off we drop the segment and return.
+ */
+ if ((tiflags & TH_ACK) == 0)
+ goto drop;
+
+ /*
+ * Ack processing.
*/
- hlen += sizeof(struct ip);
- mp->m_off += hlen;
- mp->m_len -= hlen;
- nstate = tp->t_state;
- tp->tc_flags &= ~TC_NET_KEEP;
- acounts[tp->t_state][INRECV]++;
-#ifdef TCPDEBUG
- if ((tp->t_ucb->uc_flags & UDEBUG) || tcpconsdebug) {
- tdb_setup(tp, n, INRECV, &tdb);
- } else
- tdb.td_tod = 0;
-#endif
switch (tp->t_state) {
- case LISTEN:
- if (!syn_ok(tp, n) ||
- ((tp->t_ucb->uc_host = h_make(&n->t_s)) == 0)) {
- nstate = EFAILEC;
- goto done;
- }
- tp->t_fport = n->t_src;
- tp->t_ucb->uc_template = tcp_template(tp);
- tcp_ctldat(tp, n, 1);
- if (tp->tc_flags&TC_FIN_RCVD) {
- tp->t_finack = T_2ML; /* 3 */
- tp->tc_flags &= ~TC_WAITED_2_ML;
- nstate = CLOSE_WAIT;
- } else {
- tp->t_init = T_INIT / 2; /* 4 */
- nstate = L_SYN_RCVD;
- }
- goto done;
+ /*
+ * In SYN_RECEIVED state if the ack ACKs our SYN then enter
+ * ESTABLISHED state and continue processing, othewise
+ * send an RST.
+ */
+ case TCPS_SYN_RECEIVED:
+ if (SEQ_GT(tp->snd_una, ti->ti_ack) ||
+ SEQ_GT(ti->ti_ack, tp->snd_max))
+ goto dropwithreset;
+ tp->snd_una++; /* SYN acked */
+ if (SEQ_LT(tp->snd_nxt, tp->snd_una))
+ tp->snd_nxt = tp->snd_una;
+ tp->t_timer[TCPT_REXMT] = 0;
+ if (so->so_options & SO_ACCEPTCONN)
+ so->so_state |= SS_CONNAWAITING;
+ soisconnected(so);
+ tp->t_state = TCPS_ESTABLISHED;
+ (void) tcp_reass(tp, (struct tcpiphdr *)0);
+ tp->snd_wl1 = ti->ti_seq - 1;
+ /* fall into ... */
- case SYN_SENT:
- if (!syn_ok(tp, n)) {
- nstate = EFAILEC;
- goto done;
+ /*
+ * In ESTABLISHED state: drop duplicate ACKs; ACK out of range
+ * ACKs. If the ack is in the range
+ * tp->snd_una < ti->ti_ack <= tp->snd_max
+ * then advance tp->snd_una to ti->ti_ack and drop
+ * data from the retransmission queue. If this ACK reflects
+ * more up to date window information we update our window information.
+ */
+ case TCPS_ESTABLISHED:
+ case TCPS_FIN_WAIT_1:
+ case TCPS_FIN_WAIT_2:
+ case TCPS_CLOSE_WAIT:
+ case TCPS_CLOSING:
+ case TCPS_LAST_ACK:
+ case TCPS_TIME_WAIT:
+#define ourfinisacked (acked > 0)
+
+ if (SEQ_LEQ(ti->ti_ack, tp->snd_una))
+ break;
+ if (SEQ_GT(ti->ti_ack, tp->snd_max))
+ goto dropafterack;
+ acked = ti->ti_ack - tp->snd_una;
+
+ /*
+ * If transmit timer is running and timed sequence
+ * number was acked, update smoothed round trip time.
+ */
+ if (tp->t_rtt && SEQ_GT(ti->ti_ack, tp->t_rtseq)) {
+ if (tp->t_srtt == 0)
+ tp->t_srtt = tp->t_rtt;
+ else
+ tp->t_srtt =
+ tcp_alpha * tp->t_srtt +
+ (1 - tcp_alpha) * tp->t_rtt;
+/* printf("rtt %d srtt*100 now %d\n", tp->t_rtt, (int)(tp->t_srtt*100)); */
+ tp->t_rtt = 0;
}
- tcp_ctldat(tp, n, 1);
- if (tp->tc_flags&TC_FIN_RCVD) {
- if ((n->th_flags&TH_ACK) == 0) {
- tp->t_finack = T_2ML; /* 9 */
- tp->tc_flags &= ~TC_WAITED_2_ML;
- }
- nstate = CLOSE_WAIT;
- goto done;
+
+ if (ti->ti_ack == tp->snd_max)
+ tp->t_timer[TCPT_REXMT] = 0;
+ else {
+ TCPT_RANGESET(tp->t_timer[TCPT_REXMT],
+ tcp_beta * tp->t_srtt, TCPTV_MIN, TCPTV_MAX);
+ tp->t_rtt = 1;
+ tp->t_rxtshift = 0;
}
- nstate = (n->th_flags&TH_ACK) ? ESTAB : SYN_RCVD; /* 11:8 */
- goto done;
-
- case SYN_RCVD:
- case L_SYN_RCVD:
- if ((n->th_flags&TH_ACK) == 0 ||
- (n->th_flags&TH_ACK) && n->t_ackno <= tp->iss) {
- nstate = EFAILEC;
- goto done;
+ if (acked > so->so_snd.sb_cc) {
+ sbdrop(&so->so_snd, so->so_snd.sb_cc);
+ tp->snd_wnd -= so->so_snd.sb_cc;
+ } else {
+ sbdrop(&so->so_snd, acked);
+ tp->snd_wnd -= acked;
+ acked = 0;
}
- goto input;
-
- case ESTAB:
- case FIN_W1:
- case FIN_W2:
- case TIME_WAIT:
-input:
- tcp_ctldat(tp, n, 1); /* 39 */
- switch (tp->t_state) {
+ if ((so->so_snd.sb_flags & SB_WAIT) || so->so_snd.sb_sel)
+ sowwakeup(so);
+ tp->snd_una = ti->ti_ack;
+ if (SEQ_LT(tp->snd_nxt, tp->snd_una))
+ tp->snd_nxt = tp->snd_una;
- case ESTAB:
- if (tp->tc_flags&TC_FIN_RCVD)
- nstate = CLOSE_WAIT;
- break;
+ switch (tp->t_state) {
- case SYN_RCVD:
- case L_SYN_RCVD:
- nstate = (tp->tc_flags&TC_FIN_RCVD) ?
- CLOSE_WAIT : ESTAB; /* 33:5 */
+ /*
+ * In FIN_WAIT_1 STATE in addition to the processing
+ * for the ESTABLISHED state if our FIN is now acknowledged
+ * then enter FIN_WAIT_2.
+ */
+ case TCPS_FIN_WAIT_1:
+ if (ourfinisacked) {
+ /*
+ * If we can't receive any more
+ * data, then closing user can proceed.
+ */
+ if (so->so_state & SS_CANTRCVMORE)
+ soisdisconnected(so);
+ tp->t_state = TCPS_FIN_WAIT_2;
+ }
break;
- case FIN_W1:
- j = ack_fin(tp, n);
- if ((tp->tc_flags & TC_FIN_RCVD) == 0) {
- if (j)
- nstate = FIN_W2; /* 27 */
- break;
+ /*
+ * In CLOSING STATE in addition to the processing for
+ * the ESTABLISHED state if the ACK acknowledges our FIN
+ * then enter the TIME-WAIT state, otherwise ignore
+ * the segment.
+ */
+ case TCPS_CLOSING:
+ if (ourfinisacked) {
+ tp->t_state = TCPS_TIME_WAIT;
+ tcp_canceltimers(tp);
+ tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+ soisdisconnected(so);
}
- tp->t_finack = T_2ML;
- tp->tc_flags &= ~TC_WAITED_2_ML;
- nstate = j ? TIME_WAIT : CLOSING1; /* 28:26 */
break;
- case FIN_W2:
- if (tp->tc_flags&TC_FIN_RCVD) {
- tp->t_finack = T_2ML; /* 29 */
- tp->tc_flags &= ~TC_WAITED_2_ML;
- nstate = TIME_WAIT;
- break;
+ /*
+ * The only thing that can arrive in LAST_ACK state
+ * is an acknowledgment of our FIN. If our FIN is now
+ * acknowledged, delete the TCB, enter the closed state
+ * and return.
+ */
+ case TCPS_LAST_ACK:
+ if (ourfinisacked) {
+ tcp_close(tp);
+ tp = 0;
}
- break;
- }
- goto done;
-
- case CLOSE_WAIT:
- if (n->th_flags&TH_FIN) {
- if ((n->th_flags&TH_ACK) &&
- n->t_ackno <= tp->seq_fin) {
- tcp_ctldat(tp, n, 0); /* 30 */
- tp->t_finack = T_2ML;
- tp->tc_flags &= ~TC_WAITED_2_ML;
- } else
- tcp_sndctl(tp); /* 31 */
- goto done;
- }
- goto input;
-
- case CLOSING1:
- j = ack_fin(tp, n);
- if (n->th_flags&TH_FIN) {
- tcp_ctldat(tp, n, 0);
- tp->t_finack = T_2ML;
- tp->tc_flags &= ~TC_WAITED_2_ML;
- if (j)
- nstate = TIME_WAIT; /* 23 */
- goto done;
- }
- if (j) {
- if (tp->tc_flags&TC_WAITED_2_ML)
- if (rcv_empty(tp)) {
- tcp_close(tp, UCLOSED); /* 15 */
- nstate = CLOSED;
- } else
- nstate = RCV_WAIT; /* 18 */
- else
- nstate = TIME_WAIT;
- goto done;
- }
- goto input;
-
- case CLOSING2:
- if (ack_fin(tp, n)) {
- if (rcv_empty(tp)) { /* 16 */
- tcp_close(tp, UCLOSED);
- nstate = CLOSED;
- } else
- nstate = RCV_WAIT; /* 19 */
- goto done;
+ goto drop;
+
+ /*
+ * In TIME_WAIT state the only thing that should arrive
+ * is a retransmission of the remote FIN. Acknowledge
+ * it and restart the finack timer.
+ */
+ case TCPS_TIME_WAIT:
+ tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+ goto dropafterack;
}
- if (n->th_flags&TH_FIN) {
- tcp_sndctl(tp); /* 31 */
- goto done;
+#undef ourfinisacked
+ }
+
+step6:
+ /*
+ * Update window information.
+ */
+ if (SEQ_LT(tp->snd_wl1, ti->ti_seq) || tp->snd_wl1 == ti->ti_seq &&
+ (SEQ_LT(tp->snd_wl2, ti->ti_ack) ||
+ tp->snd_wl2 == ti->ti_ack && ti->ti_win > tp->snd_wnd)) {
+ tp->snd_wnd = ti->ti_win;
+ tp->snd_wl1 = ti->ti_seq;
+ tp->snd_wl2 = ti->ti_ack;
+ if (tp->snd_wnd > 0)
+ tp->t_timer[TCPT_PERSIST] = 0;
+ }
+
+ /*
+ * Process segments with URG.
+ */
+ if ((tiflags & TH_URG) && TCPS_HAVERCVDFIN(tp->t_state) == 0) {
+ /*
+ * If this segment advances the known urgent pointer,
+ * then mark the data stream. This should not happen
+ * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since
+ * a FIN has been received from the remote side.
+ * In these states we ignore the URG.
+ */
+ if (SEQ_GT(ti->ti_seq+ti->ti_urp, tp->rcv_up)) {
+ tp->rcv_up = ti->ti_seq + ti->ti_urp;
+ so->so_oobmark = so->so_rcv.sb_cc +
+ (tp->rcv_up - tp->rcv_nxt) - 1;
+ if (so->so_oobmark == 0)
+ so->so_state |= SS_RCVATMARK;
+#ifdef TCPTRUEOOB
+ if ((tp->t_flags & TF_DOOOB) == 0)
+#endif
+ sohasoutofband(so);
+ tp->t_oobflags &= ~TCPOOB_HAVEDATA;
}
- goto input;
-
- case RCV_WAIT:
- if ((n->th_flags&TH_FIN) && (n->th_flags&TH_ACK) &&
- n->t_ackno <= tp->seq_fin) {
- tcp_ctldat(tp, n, 0);
- tp->t_finack = T_2ML;
- tp->tc_flags &= ~TC_WAITED_2_ML; /* 30 */
+ /*
+ * Remove out of band data so doesn't get presented to user.
+ * This can happen independent of advancing the URG pointer,
+ * but if two URG's are pending at once, some out-of-band
+ * data may creep in... ick.
+ */
+ if (ti->ti_urp <= ti->ti_len) {
+ tcp_pulloutofband(so, ti);
}
- goto done;
}
- panic("tcp_input");
-done:
/*
- * Done with state*input specific processing.
- * Form trace records, free input if not needed,
- * and enter new state.
+ * Process the segment text, merging it into the TCP sequencing queue,
+ * and arranging for acknowledgment of receipt if necessary.
+ * This process logically involves adjusting tp->rcv_wnd as data
+ * is presented to the user (this happens in tcp_usrreq.c,
+ * case PRU_RCVD). If a FIN has already been received on this
+ * connection then we just ignore the text.
*/
-#ifdef TCPDEBUG
- if (tdb.td_tod)
- tdb_stuff(&tdb, nstate);
-#endif
- switch (nstate) {
+ if ((ti->ti_len || (tiflags&TH_FIN)) &&
+ TCPS_HAVERCVDFIN(tp->t_state) == 0) {
+ tiflags = tcp_reass(tp, ti);
+ if (tcpnodelack == 0)
+ tp->t_flags |= TF_DELACK;
+ else
+ tp->t_flags |= TF_ACKNOW;
+ } else {
+ m_freem(m);
+ tiflags &= ~TH_FIN;
+ }
- case EFAILEC:
- m_freem(mp);
- return;
+ /*
+ * If FIN is received ACK the FIN and let the user know
+ * that the connection is closing.
+ */
+ if (tiflags & TH_FIN) {
+ if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
+ socantrcvmore(so);
+ tp->t_flags |= TF_ACKNOW;
+ tp->rcv_nxt++;
+ }
+ switch (tp->t_state) {
- default:
- tp->t_state = nstate;
- /* fall into ... */
+ /*
+ * In SYN_RECEIVED and ESTABLISHED STATES
+ * enter the CLOSE_WAIT state.
+ */
+ case TCPS_SYN_RECEIVED:
+ case TCPS_ESTABLISHED:
+ tp->t_state = TCPS_CLOSE_WAIT;
+ break;
- case CLOSED:
- /* IF CLOSED CANT LOOK AT tc_flags */
- if ((tp->tc_flags&TC_NET_KEEP) == 0)
- /* inline expansion of m_freem */
- while (mp) {
- MFREE(mp, m);
- mp = m;
- }
- return;
+ /*
+ * If still in FIN_WAIT_1 STATE FIN has not been acked so
+ * enter the CLOSING state.
+ */
+ case TCPS_FIN_WAIT_1:
+ tp->t_state = TCPS_CLOSING;
+ break;
+
+ /*
+ * In FIN_WAIT_2 state enter the TIME_WAIT state,
+ * starting the time-wait timer, turning off the other
+ * standard timers.
+ */
+ case TCPS_FIN_WAIT_2:
+ tp->t_state = TCPS_TIME_WAIT;
+ tcp_canceltimers(tp);
+ tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+ soisdisconnected(so);
+ break;
+
+ /*
+ * In TIME_WAIT state restart the 2 MSL time_wait timer.
+ */
+ case TCPS_TIME_WAIT:
+ tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+ break;
+ }
}
- /* NOTREACHED */
+ if (so->so_options & SO_DEBUG)
+ tcp_trace(TA_INPUT, ostate, tp, &tcp_saveti, 0);
+
+ /*
+ * Return any desired output.
+ */
+ (void) tcp_output(tp);
+ return;
+
+dropafterack:
+ /*
+ * Generate an ACK dropping incoming segment if it occupies
+ * sequence space, where the ACK reflects our state.
+ */
+ if ((tiflags&TH_RST) ||
+ tlen == 0 && (tiflags&(TH_SYN|TH_FIN)) == 0)
+ goto drop;
+ if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)
+ tcp_trace(TA_RESPOND, ostate, tp, &tcp_saveti, 0);
+ tcp_respond(tp, ti, tp->rcv_nxt, tp->snd_nxt, TH_ACK);
+ return;
+dropwithreset:
+ if (om)
+ (void) m_free(om);
/*
- * Unwanted packed; free everything
- * but the header and return an rst.
+ * Generate a RST, dropping incoming segment.
+ * Make ACK acceptable to originator of segment.
*/
-notwanted:
- m_freem(mp->m_next);
- mp->m_next = NULL;
- mp->m_len = sizeof(struct th);
-#define xchg(a,b) j=a; a=b; b=j
- xchg(n->t_d.s_addr, n->t_s.s_addr); xchg(n->t_dst, n->t_src);
-#undef xchg
- if (n->th_flags&TH_ACK)
- n->t_seq = n->t_ackno;
+ if (tiflags & TH_RST)
+ goto drop;
+ if (tiflags & TH_ACK)
+ tcp_respond(tp, ti, (tcp_seq)0, ti->ti_ack, TH_RST);
else {
- n->t_ackno = htonl(ntohl(n->t_seq) + tlen - hlen);
- n->t_seq = 0;
+ if (tiflags & TH_SYN)
+ ti->ti_len++;
+ tcp_respond(tp, ti, ti->ti_seq+ti->ti_len, (tcp_seq)0,
+ TH_RST|TH_ACK);
}
- n->th_flags = TH_RST; /* not TH_FIN, TH_SYN */
- n->th_flags ^= TH_ACK;
- n->t_len = htons(TCPSIZE);
- n->t_off = 5;
- n->t_sum = cksum(mp, sizeof(struct th));
- ((struct ip *)n)->ip_len = sizeof(struct th);
- ip_output(mp);
- netstat.t_badsegs++;
+ return;
+
+drop:
+ /*
+ * Drop space held by incoming segment and return.
+ */
+ if (tp && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG))
+ tcp_trace(TA_DROP, ostate, tp, &tcp_saveti, 0);
+ m_freem(m);
+ return;
}
-tcp_ctldat(tp, n, dataok)
- register struct tcb *tp;
- register struct th *n;
+tcp_dooptions(tp, om)
+ struct tcpcb *tp;
+ struct mbuf *om;
{
- register struct mbuf *m;
- int sent;
-COUNT(TCP_CTLDAT);
-
- tp->tc_flags &= ~(TC_DROPPED_TXT|TC_ACK_DUE|TC_NEW_WINDOW);
-/* syn */
- if ((tp->tc_flags&TC_SYN_RCVD) == 0 && (n->th_flags&TH_SYN)) {
- tp->irs = n->t_seq;
- tp->rcv_nxt = n->t_seq + 1;
- tp->snd_wl = tp->rcv_urp = tp->irs;
- tp->tc_flags |= (TC_SYN_RCVD|TC_ACK_DUE);
- }
-/* ack */
- if ((n->th_flags&TH_ACK) && (tp->tc_flags&TC_SYN_RCVD) &&
- n->t_ackno > tp->snd_una) {
- register struct mbuf *mn;
- register struct ucb *up;
- int len;
-
- up = tp->t_ucb;
-
- /* update snd_una and snd_nxt */
- tp->snd_una = n->t_ackno;
- if (tp->snd_una > tp->snd_nxt)
- tp->snd_nxt = tp->snd_una;
- /* if timed msg acked, set retrans time value */
- if ((tp->tc_flags&TC_SYN_ACKED) &&
- tp->snd_una > tp->t_xmt_val) {
- tp->t_xmtime = (tp->t_xmt != 0 ? tp->t_xmt : T_REXMT);
- if (tp->t_xmtime > T_REMAX)
- tp->t_xmtime = T_REMAX;
+ register u_char *cp;
+ int opt, optlen, cnt;
+
+ cp = mtod(om, u_char *);
+ cnt = om->m_len;
+ for (; cnt > 0; cnt -= optlen, cp += optlen) {
+ opt = cp[0];
+ if (opt == TCPOPT_EOL)
+ break;
+ if (opt == TCPOPT_NOP)
+ optlen = 1;
+ else
+ optlen = cp[1];
+ switch (opt) {
+
+ default:
+ break;
+
+ case TCPOPT_MAXSEG:
+ if (optlen != 4)
+ continue;
+ tp->t_maxseg = *(u_short *)(cp + 2);
+#if vax || pdp11
+ tp->t_maxseg = ntohs((u_short)tp->t_maxseg);
+#endif
+ break;
+
+#ifdef TCPTRUEOOB
+ case TCPOPT_WILLOOB:
+ tp->t_flags |= TF_DOOOB;
+printf("tp %x dooob\n", tp);
+ break;
+
+ case TCPOPT_OOBDATA: {
+ int seq;
+ register struct socket *so = tp->t_inpcb->inp_socket;
+ tcp_seq mark;
+
+ if (optlen != 8)
+ continue;
+ seq = cp[2];
+ if (seq < tp->t_iobseq)
+ seq += 256;
+printf("oobdata cp[2] %d iobseq %d seq %d\n", cp[2], tp->t_iobseq, seq);
+ if (seq - tp->t_iobseq > 128) {
+printf("bad seq\n");
+ tp->t_oobflags |= TCPOOB_OWEACK;
+ break;
+ }
+ tp->t_iobseq = cp[2];
+ tp->t_iobc = cp[3];
+ mark = *(tcp_seq *)(cp + 4);
+#if vax || pdp11
+ mark = ntohl(mark);
+#endif
+ so->so_oobmark = so->so_rcv.sb_cc + (mark-tp->rcv_nxt);
+ if (so->so_oobmark == 0)
+ so->so_state |= SS_RCVATMARK;
+printf("take oob data %x input iobseq now %x\n", tp->t_iobc, tp->t_iobseq);
+ sohasoutofband(so);
+ break;
}
- /* remove acked data from send buf */
- len = tp->snd_una - tp->snd_off;
- m = up->uc_sbuf;
- while (len > 0 && m != NULL)
- if (m->m_len <= len) {
- len -= m->m_len;
- if (m->m_off > MMAXOFF)
- up->uc_ssize -= NMBPG;
- MFREE(m, mn);
- m = mn;
- up->uc_ssize--;
- } else {
- m->m_len -= len;
- m->m_off += len;
+ case TCPOPT_OOBACK: {
+ int seq;
+
+ if (optlen != 4)
+ continue;
+ if (tp->t_oobseq != cp[2]) {
+printf("wrong ack\n");
break;
}
- up->uc_sbuf = m;
- tp->snd_off = tp->snd_una;
- if ((tp->tc_flags&TC_SYN_ACKED) == 0 &&
- (tp->snd_una > tp->iss)) {
- tp->tc_flags |= TC_SYN_ACKED;
- tp->t_init = 0;
+printf("take oob ack %x and cancel rexmt\n", cp[2]);
+ tp->t_oobflags &= ~TCPOOB_NEEDACK;
+ tp->t_timer[TCPT_OOBREXMT] = 0;
+ break;
+ }
+#endif TCPTRUEOOB
}
- if (tp->seq_fin != tp->iss && tp->snd_una > tp->seq_fin)
- tp->tc_flags &= ~TC_SND_FIN;
- tp->t_rexmt = 0;
- tp->t_rexmttl = 0;
- tp->tc_flags |= TC_CANCELLED;
- netwakeup(tp->t_ucb); /* wasteful */
- }
-/* win */
- if ((tp->tc_flags & TC_SYN_RCVD) && n->t_seq >= tp->snd_wl) {
- tp->snd_wl = n->t_seq;
- tp->snd_wnd = n->t_win;
- tp->tc_flags |= TC_NEW_WINDOW;
- tp->t_persist = 0;
}
- if (dataok == 0)
- goto ctlonly;
-/* text */
- if (n->t_len == 0)
- goto notext;
- { register int i;
- register struct th *p, *q;
- register struct mbuf *m;
- int overage;
-
- /*
- * Discard duplicate data already passed to user.
- */
- if (SEQ_LT(n->t_seq, tp->rcv_nxt)) {
- i = tp->rcv_nxt - n->t_seq;
- if (i >= n->t_len)
- goto notext;
- n->t_seq += i;
- n->t_len -= i;
- m_adj(dtom(n), i);
+ (void) m_free(om);
+}
+
+/*
+ * Pull out of band byte out of a segment so
+ * it doesn't appear in the user's data queue.
+ * It is still reflected in the segment length for
+ * sequencing purposes.
+ */
+tcp_pulloutofband(so, ti)
+ struct socket *so;
+ struct tcpiphdr *ti;
+{
+ register struct mbuf *m;
+ int cnt = ti->ti_urp - 1;
+
+ m = dtom(ti);
+ while (cnt >= 0) {
+ if (m->m_len > cnt) {
+ char *cp = mtod(m, caddr_t) + cnt;
+ struct tcpcb *tp = sototcpcb(so);
+
+ tp->t_iobc = *cp;
+ tp->t_oobflags |= TCPOOB_HAVEDATA;
+ bcopy(cp+1, cp, (unsigned)(m->m_len - cnt - 1));
+ m->m_len--;
+ return;
+ }
+ cnt -= m->m_len;
+ m = m->m_next;
+ if (m == 0)
+ break;
}
+ panic("tcp_pulloutofband");
+}
+
+/*
+ * Insert segment ti into reassembly queue of tcp with
+ * control block tp. Return TH_FIN if reassembly now includes
+ * a segment with FIN.
+ */
+tcp_reass(tp, ti)
+ register struct tcpcb *tp;
+ register struct tcpiphdr *ti;
+{
+ register struct tcpiphdr *q;
+ struct socket *so = tp->t_inpcb->inp_socket;
+ struct mbuf *m;
+ int flags;
+
+ /*
+ * Call with ti==0 after become established to
+ * force pre-ESTABLISHED data up to user socket.
+ */
+ if (ti == 0)
+ goto present;
/*
* Find a segment which begins after this one does.
*/
- for (q = tp->t_rcv_next; q != (struct th *)tp; q = q->t_next)
- if (SEQ_GT(q->t_seq, n->t_seq))
+ for (q = tp->seg_next; q != (struct tcpiphdr *)tp;
+ q = (struct tcpiphdr *)q->ti_next)
+ if (SEQ_GT(q->ti_seq, ti->ti_seq))
break;
/*
* our data already. If so, drop the data from the incoming
* segment. If it provides all of our data, drop us.
*/
- if (q->t_prev != (struct th *)tp) {
+ if ((struct tcpiphdr *)q->ti_prev != (struct tcpiphdr *)tp) {
+ register int i;
+ q = (struct tcpiphdr *)q->ti_prev;
/* conversion to int (in i) handles seq wraparound */
- i = q->t_prev->t_seq + q->t_prev->t_len - n->t_seq;
+ i = q->ti_seq + q->ti_len - ti->ti_seq;
if (i > 0) {
- if (i >= n->t_len)
- goto notext; /* w/o setting TC_NET_KEEP */
+ if (i >= ti->ti_len)
+ goto drop;
m_adj(dtom(tp), i);
- n->t_len -= i;
- n->t_seq += i;
+ ti->ti_len -= i;
+ ti->ti_seq += i;
}
+ q = (struct tcpiphdr *)(q->ti_next);
}
/*
* While we overlap succeeding segments trim them or,
* if they are completely covered, dequeue them.
*/
- while (q != (struct th *)tp && SEQ_GT(n->t_seq + n->t_len, q->t_seq)) {
- i = (n->t_seq + n->t_len) - q->t_seq;
- if (i < q->t_len) {
- q->t_len -= i;
+ while (q != (struct tcpiphdr *)tp) {
+ register int i = (ti->ti_seq + ti->ti_len) - q->ti_seq;
+ if (i <= 0)
+ break;
+ if (i < q->ti_len) {
+ q->ti_seq += i;
+ q->ti_len -= i;
m_adj(dtom(q), i);
break;
}
- q = q->t_next;
- m_freem(dtom(q->t_prev));
- remque(q->t_prev);
+ q = (struct tcpiphdr *)q->ti_next;
+ m = dtom(q->ti_prev);
+ remque(q->ti_prev);
+ m_freem(m);
}
/*
* Stick new segment in its place.
*/
- insque(n, q->t_prev);
- tp->seqcnt += n->t_len;
-
-#ifdef notdef
- /*
- * Calculate available space and discard segments for
- * which there is too much.
- */
- q = tp->t_rcv_prev;
- overage =
- (tp->t_ucb->uc_rcc + tp->rcv_seqcnt) - tp->t_ucb->uc_rhiwat;
- if (overage > 0)
- for (;;) {
- i = MIN(q->t_len, overage);
- overage -= i;
- q->t_len -= i;
- m_adj(q, -i);
- if (q == n)
- tp->tc_flags |= TC_DROPPED_TXT;
- if (q->t_len)
- break;
- if (q == n)
- panic("tcp_text dropall");
- q = q->t_prev;
- remque(q->t_next);
- }
-#endif
+ insque(ti, q->ti_prev);
+present:
/*
- * Advance rcv_next through
- * newly completed sequence space
- * and return forcing an ack.
+ * Present data to user, advancing rcv_nxt through
+ * completed sequence space.
*/
- while (n->t_seq == tp->rcv_nxt) {
- /* present data belongs here */
- tp->rcv_nxt += n->t_len;
- n = n->t_next;
- if (n == (struct th *)tp)
- break;
- }
- tp->tc_flags |= (TC_ACK_DUE|TC_NET_KEEP);
- }
-notext:
-urgeolfin:
-/* urg */
- if (n->th_flags&TH_URG) {
- unsigned urgent;
-
- urgent = n->t_urp + n->t_seq;
- if (tp->rcv_nxt < urgent) {
- if (tp->rcv_urp <= tp->rcv_nxt)
- to_user(tp->t_ucb, UURGENT);
- tp->rcv_urp = urgent;
- }
- }
-/* eol */
- if ((n->th_flags&TH_EOL) &&
- (tp->tc_flags&TC_DROPPED_TXT) == 0 &&
- tp->t_rcv_prev != (struct th *)tp) {
- /* mark last mbuf */
- m = dtom(tp->t_rcv_prev);
- if (m != NULL) {
- while (m->m_next != NULL)
- m = m->m_next;
- m->m_act =
- (struct mbuf *)(m->m_off + m->m_len - 1);
- }
- }
-ctlonly:
-/* fin */
- if ((n->th_flags&TH_FIN) && (tp->tc_flags&TC_DROPPED_TXT) == 0) {
- seq_t last;
-
- if ((tp->tc_flags&TC_FIN_RCVD) == 0) {
- /* do we really have fin ? */
- last = firstempty(tp);
- if (tp->t_rcv_prev == (struct th *)tp ||
- last == t_end(tp->t_rcv_prev)) {
- tp->tc_flags |= TC_FIN_RCVD;
- netwakeup(tp->t_ucb); /* poke */
- }
- if ((tp->tc_flags&TC_FIN_RCVD) &&
- tp->rcv_nxt >= last) {
- tp->rcv_nxt = last + 1; /* fin seq */
- tp->tc_flags |= TC_ACK_DUE;
- }
- } else
- tp->tc_flags |= TC_ACK_DUE;
- }
-
-/* respond */
- sent = 0;
- if (tp->tc_flags&TC_ACK_DUE)
- sent = tcp_sndctl(tp);
- else if (tp->tc_flags&TC_NEW_WINDOW) {
- seq_t last = tp->snd_off;
- for (m = tp->t_ucb->uc_sbuf; m != NULL; m = m->m_next) /*###*/
- last += m->m_len; /*###*/
- if (tp->snd_nxt <= last || (tp->tc_flags&TC_SND_FIN))
- sent = tcp_send(tp);
- }
-
-/* set for retrans */
- if (!sent && tp->snd_una < tp->snd_nxt &&
- (tp->tc_flags&TC_CANCELLED)) {
- tp->t_rexmt = tp->t_xmtime;
- tp->t_rexmttl = T_REXMTTL;
- tp->t_rexmt_val = tp->t_rtl_val = tp->snd_lst;
- tp->tc_flags &= ~TC_CANCELLED;
- }
-/* present data to user */
- { register struct mbuf **mp;
- register struct ucb *up = tp->t_ucb;
- seq_t ready;
-
- /* connection must be synced and data available for user */
- if ((tp->tc_flags&TC_SYN_ACKED) == 0)
- return;
- up = tp->t_ucb;
- mp = &up->uc_rbuf;
- while (*mp)
- mp = &(*mp)->m_next;
- n = tp->t_rcv_next;
- /* SHOULD PACK DATA IN HERE */
- while (n != (struct th *)tp && n->t_seq < tp->rcv_nxt) {
- remque(n);
- m = dtom(n);
- up->uc_rcc += n->t_len;
- tp->seqcnt -= n->t_len;
- if (tp->seqcnt < 0) panic("present_data");
- n = n->t_next;
- while (m) {
- if (m->m_len == 0) {
- m = m_free(m);
- continue;
- }
- *mp = m;
- mp = &m->m_next;
- m = *mp;
- }
- }
- if (up->uc_rcc != 0)
- netwakeup(up);
- if ((tp->tc_flags&TC_FIN_RCVD) && /* ### */
- (tp->tc_flags&TC_USR_CLOSED) == 0 && /* ### */
- rcv_empty(tp)) /* ### */
- to_user(up, UCLOSED); /* ### */
- }
+ if (TCPS_HAVERCVDSYN(tp->t_state) == 0)
+ return (0);
+ ti = tp->seg_next;
+ if (ti == (struct tcpiphdr *)tp || ti->ti_seq != tp->rcv_nxt)
+ return (0);
+ if (tp->t_state == TCPS_SYN_RECEIVED && ti->ti_len)
+ return (0);
+ do {
+ tp->rcv_nxt += ti->ti_len;
+ flags = ti->ti_flags & TH_FIN;
+ remque(ti);
+ m = dtom(ti);
+ ti = (struct tcpiphdr *)ti->ti_next;
+ if (so->so_state & SS_CANTRCVMORE)
+ m_freem(m);
+ else
+ sbappend(&so->so_rcv, m);
+ } while (ti != (struct tcpiphdr *)tp && ti->ti_seq == tp->rcv_nxt);
+ sorwakeup(so);
+ return (flags);
+drop:
+ m_freem(dtom(ti));
+ return (0);
}