diff options
Diffstat (limited to 'sys/netinet/tcp_input.c')
| -rw-r--r-- | sys/netinet/tcp_input.c | 68 |
1 files changed, 64 insertions, 4 deletions
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c index fda53e3390331..6fc843a7bdc92 100644 --- a/sys/netinet/tcp_input.c +++ b/sys/netinet/tcp_input.c @@ -31,7 +31,7 @@ * SUCH DAMAGE. * * From: @(#)tcp_input.c 8.5 (Berkeley) 4/10/94 - * $Id: tcp_input.c,v 1.25.4.5 1996/09/19 08:18:28 pst Exp $ + * $Id: tcp_input.c,v 1.25.4.7 1996/11/20 18:25:30 pst Exp $ */ #ifndef TUBA_INCLUDE @@ -44,6 +44,7 @@ #include <sys/socketvar.h> #include <sys/errno.h> #include <sys/queue.h> +#include <sys/kernel.h> #include <net/if.h> #include <net/route.h> @@ -380,11 +381,65 @@ findpcb: #endif if (so->so_options & SO_ACCEPTCONN) { register struct tcpcb *tp0 = tp; - so = sonewconn(so, 0); - if (so == 0) { - tcpstat.tcps_listendrop++; + struct socket *so2; + if ((tiflags & (TH_RST|TH_ACK|TH_SYN)) != TH_SYN) { + /* + * Note: dropwithreset makes sure we don't + * send a RST in response to a RST. + */ + if (tiflags & TH_ACK) { + tcpstat.tcps_badsyn++; + goto dropwithreset; + } goto drop; } + so2 = sonewconn(so, 0); + if (so2 == 0) { + unsigned int i, j, qlen; + + static int rnd; + static long old_mono_secs; + static unsigned int cur_cnt, old_cnt; + + tcpstat.tcps_listendrop++; + + /* + * Keep a decaying average of the number + * of overruns we've been getting. + */ + if ((i = (mono_time.tv_sec - + old_mono_secs)) != 0) { + old_mono_secs = mono_time.tv_sec; + old_cnt = cur_cnt / i; + cur_cnt = 0; + } + + so2 = so->so_q0; + if (so2 == 0) + goto drop; + + /* + * If we've been getting a lot of hits, + * random drop an incomplete connection + * from the queue, otherwise, fall through + * so we head-drop from the queue. + */ + qlen = so->so_q0len; + if (++cur_cnt > qlen || old_cnt > qlen) { + rnd = (314159 * rnd + 66329) & 0xffff; + j = ((qlen + 1) * rnd) >> 16; + + while (j-- && so2) + so2 = so2->so_q0; + } + if (so2) { + tcp_drop(sototcpcb(so2), ETIMEDOUT); + so2 = sonewconn(so, 0); + } + if (!so2) + goto drop; + } + so = so2; /* * This is ugly, but .... * @@ -710,6 +765,8 @@ findpcb: } /* + * If the state is SYN_RECEIVED: + * do just the ack and RST checks from SYN_SENT state. * 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. @@ -721,6 +778,7 @@ findpcb: * arrange for segment to be acked (eventually) * continue processing rest of data/controls, beginning with URG */ + case TCPS_SYN_RECEIVED: case TCPS_SYN_SENT: if ((taop = tcp_gettaocache(inp)) == NULL) { taop = &tao_noncached; @@ -748,6 +806,8 @@ findpcb: tp = tcp_drop(tp, ECONNREFUSED); goto drop; } + if (tp->t_state == TCPS_SYN_RECEIVED) + break; if ((tiflags & TH_SYN) == 0) goto drop; tp->snd_wnd = ti->ti_win; /* initial send window */ |