tcp_debug.c

Go to the documentation of this file.

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1986, 1993
 *      The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)tcp_debug.c 8.1 (Berkeley) 6/10/93
 */
 
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
 
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_tcpdebug.h"
 
#ifdef TCPDEBUG
/* load symbolic names */
#define PRUREQUESTS
#define TCPSTATES
#define TCPTIMERS
#define TANAMES
#endif
 
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/protosw.h>
#include <sys/socket.h>
 
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#ifdef INET6
#include <netinet/ip6.h>
#endif
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/tcpip.h>
#include <netinet/tcp_debug.h>
 
#ifdef TCPDEBUG
static int              tcpconsdebug = 0;
#endif
 
/*
 * Global ring buffer of TCP debugging state.  Each entry captures a snapshot
 * of TCP connection state at any given moment.  tcp_debx addresses at the
 * next available slot.  There is no explicit export of this data structure;
 * it will be read via /dev/kmem by debugging tools.
 */
static struct tcp_debug tcp_debug[TCP_NDEBUG];
static int              tcp_debx;
 
/*
 * All global state is protected by tcp_debug_mtx; tcp_trace() is split into
 * two parts, one of which saves connection and other state into the global
 * array (locked by tcp_debug_mtx).
 */
struct mtx              tcp_debug_mtx;
MTX_SYSINIT(tcp_debug_mtx, &tcp_debug_mtx, "tcp_debug_mtx", MTX_DEF);
 
/*
 * Save TCP state at a given moment; optionally, both tcpcb and TCP packet
 * header state will be saved.
 */
void
tcp_trace(short act, short ostate, struct tcpcb *tp, void *ipgen,
    struct tcphdr *th, int req)
{
#ifdef INET6
        int isipv6;
#endif /* INET6 */
        tcp_seq seq, ack;
        int len, flags;
        struct tcp_debug *td;
 
        mtx_lock(&tcp_debug_mtx);
        td = &tcp_debug[tcp_debx++];
        if (tcp_debx == TCP_NDEBUG)
                tcp_debx = 0;
        bzero(td, sizeof(*td));
#ifdef INET6
        isipv6 = (ipgen != NULL && ((struct ip *)ipgen)->ip_v == 6) ? 1 : 0;
#endif /* INET6 */
        td->td_family =
#ifdef INET6
            (isipv6 != 0) ? AF_INET6 :
#endif
            AF_INET;
#ifdef INET
        td->td_time = iptime();
#endif
        td->td_act = act;
        td->td_ostate = ostate;
        td->td_tcb = (caddr_t)tp;
        if (tp != NULL)
                td->td_cb = *tp;
        if (ipgen != NULL) {
                switch (td->td_family) {
#ifdef INET
                case AF_INET:
                        bcopy(ipgen, &td->td_ti.ti_i, sizeof(td->td_ti.ti_i));
                        break;
#endif
#ifdef INET6
                case AF_INET6:
                        bcopy(ipgen, td->td_ip6buf, sizeof(td->td_ip6buf));
                        break;
#endif
                }
        }
        if (th != NULL) {
                switch (td->td_family) {
#ifdef INET
                case AF_INET:
                        td->td_ti.ti_t = *th;
                        break;
#endif
#ifdef INET6
                case AF_INET6:
                        td->td_ti6.th = *th;
                        break;
#endif
                }
        }
        td->td_req = req;
        mtx_unlock(&tcp_debug_mtx);
#ifdef TCPDEBUG
        if (tcpconsdebug == 0)
                return;
        if (tp != NULL)
                printf("%p %s:", tp, tcpstates[ostate]);
        else
                printf("???????? ");
        printf("%s ", tanames[act]);
        switch (act) {
        case TA_INPUT:
        case TA_OUTPUT:
        case TA_DROP:
                if (ipgen == NULL || th == NULL)
                        break;
                seq = th->th_seq;
                ack = th->th_ack;
                len =
#ifdef INET6
                    isipv6 ? ntohs(((struct ip6_hdr *)ipgen)->ip6_plen) :
#endif
                    ntohs(((struct ip *)ipgen)->ip_len);
                if (act == TA_OUTPUT) {
                        seq = ntohl(seq);
                        ack = ntohl(ack);
                }
                if (act == TA_OUTPUT)
                        len -= sizeof (struct tcphdr);
                if (len)
                        printf("[%x..%x)", seq, seq+len);
                else
                        printf("%x", seq);
                printf("@%x, urp=%x", ack, th->th_urp);
                flags = tcp_get_flags(th);
                if (flags) {
                        char *cp = "<";
#define pf(f) {                                 \
        if (tcp_get_flags(th) & TH_##f) {       \
                printf("%s%s", cp, #f);         \
                cp = ",";                       \
        }                                       \
}
                        pf(SYN); pf(ACK); pf(FIN); pf(RST); pf(PUSH); pf(URG);
                        printf(">");
                }
                break;
 
        case TA_USER:
                printf("%s", prurequests[req&0xff]);
                if ((req & 0xff) == PRU_SLOWTIMO)
                        printf("<%s>", tcptimers[req>>8]);
                break;
        }
        if (tp != NULL)
                printf(" -> %s", tcpstates[tp->t_state]);
        /* print out internal state of tp !?! */
        printf("\n");
        if (tp == NULL)
                return;
        printf(
        "\trcv_(nxt,wnd,up) (%lx,%lx,%lx) snd_(una,nxt,max) (%lx,%lx,%lx)\n",
            (u_long)tp->rcv_nxt, (u_long)tp->rcv_wnd, (u_long)tp->rcv_up,
            (u_long)tp->snd_una, (u_long)tp->snd_nxt, (u_long)tp->snd_max);
        printf("\tsnd_(wl1,wl2,wnd) (%lx,%lx,%lx)\n",
            (u_long)tp->snd_wl1, (u_long)tp->snd_wl2, (u_long)tp->snd_wnd);
#endif /* TCPDEBUG */
}