ipcp.c

自己精简过的PPPD代码。在嵌入中应用可以更好的发挥。比原先的小了很多

    if (!sifaddr(u, wo->ouraddr, wo->hisaddr, GetMask(wo->ouraddr)))
	return 0;
    ipcp_script(_PATH_IPPREUP, 1);
    if (!sifup(u))
	return 0;
    if (!sifnpmode(u, PPP_IP, NPMODE_QUEUE))
	return 0;
    if (wo->default_route)
	if (sifdefaultroute(u, wo->ouraddr, wo->hisaddr))
	    default_route_set[u] = 1;
    if (wo->proxy_arp)
	if (sifproxyarp(u, wo->hisaddr))
	    proxy_arp_set[u] = 1;

    notice("local  IP address %I", wo->ouraddr);
    notice("remote IP address %I", wo->hisaddr);

    return 1;
}


/*
 * ipcp_up - IPCP has come UP.
 *
 * Configure the IP network interface appropriately and bring it up.
 */
static void
ipcp_up(f)
    fsm *f;
{
    u_int32_t mask;
    ipcp_options *ho = &ipcp_hisoptions[f->unit];
    ipcp_options *go = &ipcp_gotoptions[f->unit];
    ipcp_options *wo = &ipcp_wantoptions[f->unit];

    IPCPDEBUG(("ipcp: up"));

    /*
     * We must have a non-zero IP address for both ends of the link.
     */
    if (!ho->neg_addr && !ho->old_addrs)
	ho->hisaddr = wo->hisaddr;

    if (!(go->neg_addr || go->old_addrs) && (wo->neg_addr || wo->old_addrs)
	&& wo->ouraddr != 0) {
	error("Peer refused to agree to our IP address");
	ipcp_close(f->unit, "Refused our IP address");
	return;
    }
    if (go->ouraddr == 0) {
	error("Could not determine local IP address");
	ipcp_close(f->unit, "Could not determine local IP address");
	return;
    }
    if (ho->hisaddr == 0) {
	ho->hisaddr = htonl(0x0a404040 + ifunit);
	warn("Could not determine remote IP address: defaulting to %I",
	     ho->hisaddr);
    }
    script_setenv("IPLOCAL", ip_ntoa(go->ouraddr), 0);
    script_setenv("IPREMOTE", ip_ntoa(ho->hisaddr), 1);

    if (go->dnsaddr[0])
	script_setenv("DNS1", ip_ntoa(go->dnsaddr[0]), 0);
    if (go->dnsaddr[1])
	script_setenv("DNS2", ip_ntoa(go->dnsaddr[1]), 0);
    if (usepeerdns && (go->dnsaddr[0] || go->dnsaddr[1])) {
	script_setenv("USEPEERDNS", "1", 0);
	create_resolv(go->dnsaddr[0], go->dnsaddr[1]);
    }

    /*
     * Check that the peer is allowed to use the IP address it wants.
     */
    if (!auth_ip_addr(f->unit, ho->hisaddr)) {
	error("Peer is not authorized to use remote address %I", ho->hisaddr);
	ipcp_close(f->unit, "Unauthorized remote IP address");
	return;
    }

    /* set tcp compression */
    sifvjcomp(f->unit, ho->neg_vj, ho->cflag, ho->maxslotindex);

    /*
     * If we are doing dial-on-demand, the interface is already
     * configured, so we put out any saved-up packets, then set the
     * interface to pass IP packets.
     */
    if (demand) {
	if (go->ouraddr != wo->ouraddr || ho->hisaddr != wo->hisaddr) {
	    ipcp_clear_addrs(f->unit, wo->ouraddr, wo->hisaddr);
	    if (go->ouraddr != wo->ouraddr) {
		warn("Local IP address changed to %I", go->ouraddr);
		script_setenv("OLDIPLOCAL", ip_ntoa(wo->ouraddr), 0);
		wo->ouraddr = go->ouraddr;
	    } else
		script_unsetenv("OLDIPLOCAL");
	    if (ho->hisaddr != wo->hisaddr) {
		warn("Remote IP address changed to %I", ho->hisaddr);
		script_setenv("OLDIPREMOTE", ip_ntoa(wo->hisaddr), 0);
		wo->hisaddr = ho->hisaddr;
	    } else
		script_unsetenv("OLDIPREMOTE");

	    /* Set the interface to the new addresses */
	    mask = GetMask(go->ouraddr);
	    if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) {
		if (debug)
		    warn("Interface configuration failed");
		ipcp_close(f->unit, "Interface configuration failed");
		return;
	    }

	    /* assign a default route through the interface if required */
	    if (ipcp_wantoptions[f->unit].default_route) 
		if (sifdefaultroute(f->unit, go->ouraddr, ho->hisaddr))
		    default_route_set[f->unit] = 1;

	    /* Make a proxy ARP entry if requested. */
	    if (ipcp_wantoptions[f->unit].proxy_arp)
		if (sifproxyarp(f->unit, ho->hisaddr))
		    proxy_arp_set[f->unit] = 1;

	}
	demand_rexmit(PPP_IP);
	sifnpmode(f->unit, PPP_IP, NPMODE_PASS);

    } else {
	/*
	 * Set IP addresses and (if specified) netmask.
	 */
	mask = GetMask(go->ouraddr);

#if !(defined(SVR4) && (defined(SNI) || defined(__USLC__)))
	if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) {
	    if (debug)
		warn("Interface configuration failed");
	    ipcp_close(f->unit, "Interface configuration failed");
	    return;
	}
#endif

	/* run the pre-up script, if any, and wait for it to finish */
	ipcp_script(_PATH_IPPREUP, 1);

	/* bring the interface up for IP */
	if (!sifup(f->unit)) {
	    if (debug)
		warn("Interface failed to come up");
	    ipcp_close(f->unit, "Interface configuration failed");
	    return;
	}

#if (defined(SVR4) && (defined(SNI) || defined(__USLC__)))
	if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) {
	    if (debug)
		warn("Interface configuration failed");
	    ipcp_close(f->unit, "Interface configuration failed");
	    return;
	}
#endif
	sifnpmode(f->unit, PPP_IP, NPMODE_PASS);

	/* assign a default route through the interface if required */
	if (ipcp_wantoptions[f->unit].default_route) 
	    if (sifdefaultroute(f->unit, go->ouraddr, ho->hisaddr))
		default_route_set[f->unit] = 1;

	/* Make a proxy ARP entry if requested. */
	if (ipcp_wantoptions[f->unit].proxy_arp)
	    if (sifproxyarp(f->unit, ho->hisaddr))
		proxy_arp_set[f->unit] = 1;

	ipcp_wantoptions[0].ouraddr = go->ouraddr;

	notice("local  IP address %I", go->ouraddr);
	notice("remote IP address %I", ho->hisaddr);
	if (go->dnsaddr[0])
	    notice("primary   DNS address %I", go->dnsaddr[0]);
	if (go->dnsaddr[1])
	    notice("secondary DNS address %I", go->dnsaddr[1]);
    }

    reset_link_stats(f->unit);

    np_up(f->unit, PPP_IP);
    ipcp_is_up = 1;

    notify(ip_up_notifier, 0);
    if (ip_up_hook)
	ip_up_hook();

    /*
     * Execute the ip-up script, like this:
     *	/etc/ppp/ip-up interface tty speed local-IP remote-IP
     */
    if (ipcp_script_state == s_down && ipcp_script_pid == 0) {
	ipcp_script_state = s_up;
	ipcp_script(_PATH_IPUP, 0);
    }
}


/*
 * ipcp_down - IPCP has gone DOWN.
 *
 * Take the IP network interface down, clear its addresses
 * and delete routes through it.
 */
static void
ipcp_down(f)
    fsm *f;
{
    IPCPDEBUG(("ipcp: down"));
    /* XXX a bit IPv4-centric here, we only need to get the stats
     * before the interface is marked down. */
    /* XXX more correct: we must get the stats before running the notifiers,
     * at least for the radius plugin */
    update_link_stats(f->unit);
    notify(ip_down_notifier, 0);
    if (ip_down_hook)
	ip_down_hook();
    if (ipcp_is_up) {
	ipcp_is_up = 0;
	np_down(f->unit, PPP_IP);
    }
    sifvjcomp(f->unit, 0, 0, 0);

    print_link_stats(); /* _after_ running the notifiers and ip_down_hook(),
			 * because print_link_stats() sets link_stats_valid
			 * to 0 (zero) */

    /*
     * If we are doing dial-on-demand, set the interface
     * to queue up outgoing packets (for now).
     */
    if (demand) {
	sifnpmode(f->unit, PPP_IP, NPMODE_QUEUE);
    } else {
	sifnpmode(f->unit, PPP_IP, NPMODE_DROP);
	sifdown(f->unit);
	ipcp_clear_addrs(f->unit, ipcp_gotoptions[f->unit].ouraddr,
			 ipcp_hisoptions[f->unit].hisaddr);
    }

    /* Execute the ip-down script */
    if (ipcp_script_state == s_up && ipcp_script_pid == 0) {
	ipcp_script_state = s_down;
	ipcp_script(_PATH_IPDOWN, 0);
    }
}


/*
 * ipcp_clear_addrs() - clear the interface addresses, routes,
 * proxy arp entries, etc.
 */
static void
ipcp_clear_addrs(unit, ouraddr, hisaddr)
    int unit;
    u_int32_t ouraddr;  /* local address */
    u_int32_t hisaddr;  /* remote address */
{
    if (proxy_arp_set[unit]) {
	cifproxyarp(unit, hisaddr);
	proxy_arp_set[unit] = 0;
    }
    if (default_route_set[unit]) {
	cifdefaultroute(unit, ouraddr, hisaddr);
	default_route_set[unit] = 0;
    }
    cifaddr(unit, ouraddr, hisaddr);
}


/*
 * ipcp_finished - possibly shut down the lower layers.
 */
static void
ipcp_finished(f)
    fsm *f;
{
	if (ipcp_is_open) {
		ipcp_is_open = 0;
		np_finished(f->unit, PPP_IP);
	}
}


/*
 * ipcp_script_done - called when the ip-up or ip-down script
 * has finished.
 */
static void
ipcp_script_done(arg)
    void *arg;
{
    ipcp_script_pid = 0;
    switch (ipcp_script_state) {
    case s_up:
	if (ipcp_fsm[0].state != OPENED) {
	    ipcp_script_state = s_down;
	    ipcp_script(_PATH_IPDOWN, 0);
	}
	break;
    case s_down:
	if (ipcp_fsm[0].state == OPENED) {
	    ipcp_script_state = s_up;
	    ipcp_script(_PATH_IPUP, 0);
	}
	break;
    }
}


/*
 * ipcp_script - Execute a script with arguments
 * interface-name tty-name speed local-IP remote-IP.
 */
static void
ipcp_script(script, wait)
    char *script;
    int wait;
{
    char strspeed[32], strlocal[32], strremote[32];
    char *argv[8];

    slprintf(strspeed, sizeof(strspeed), "%d", baud_rate);
    slprintf(strlocal, sizeof(strlocal), "%I", ipcp_gotoptions[0].ouraddr);
    slprintf(strremote, sizeof(strremote), "%I", ipcp_hisoptions[0].hisaddr);

    argv[0] = script;
    argv[1] = ifname;
    argv[2] = devnam;
    argv[3] = strspeed;
    argv[4] = strlocal;
    argv[5] = strremote;
    argv[6] = ipparam;
    argv[7] = NULL;
    if (wait)
	run_program(script, argv, 0, NULL, NULL, 1);
    else
	ipcp_script_pid = run_program(script, argv, 0, ipcp_script_done,
				      NULL, 0);
}

/*
 * create_resolv - create the replacement resolv.conf file
 */
static void
create_resolv(peerdns1, peerdns2)
    u_int32_t peerdns1, peerdns2;
{
    FILE *f;

    f = fopen(_PATH_RESOLV, "w");
    if (f == NULL) {
	error("Failed to create %s: %m", _PATH_RESOLV);
	return;
    }

    if (peerdns1)
	fprintf(f, "nameserver %s\n", ip_ntoa(peerdns1));

    if (peerdns2)
	fprintf(f, "nameserver %s\n", ip_ntoa(peerdns2));

    if (ferror(f))
	error("Write failed to %s: %m", _PATH_RESOLV);

    fclose(f);
}

/*
 * ipcp_printpkt - print the contents of an IPCP packet.
 */
static char *ipcp_codenames[] = {
    "ConfReq", "ConfAck", "ConfNak", "ConfRej",
    "TermReq", "TermAck", "CodeRej"
};

static int
ipcp_printpkt(p, plen, printer, arg)
    u_char *p;
    int plen;
    void (*printer) __P((void *, char *, ...));
    void *arg;
{
    int code, id, len, olen;
    u_char *pstart, *optend;
    u_short cishort;
    u_int32_t cilong;

    if (plen < HEADERLEN)
	return 0;
    pstart = p;
    GETCHAR(code, p);
    GETCHAR(id, p);
    GETSHORT(len, p);
    if (len < HEADERLEN || len > plen)
	return 0;

    if (code >= 1 && code <= sizeof(ipcp_codenames) / sizeof(char *))
	printer(arg, " %s", ipcp_codenames[code-1]);
    else
	printer(arg, " code=0x%x", code);
    printer(arg, " id=0x%x", id);
    len -= HEADERLEN;
    switch (code) {
    case CONFREQ:
    case CONFACK:
    case CONFNAK:
    case CONFREJ:
	/* print option list */
	while (len >= 2) {
	    GETCHAR(code, p);
	    GETCHAR(olen, p);
	    p -= 2;
	    if (olen < 2 || olen > len) {
		break;
	    }
	    printer(arg, " <");
	    len -= olen;
	    optend = p + olen;
	    switch (code) {
	    case CI_ADDRS:
		if (olen == CILEN_ADDRS) {
		    p += 2;
		    GETLONG(cilong, p);
		    printer(arg, "addrs %I", htonl(cilong));
		    GETLONG(cilong, p);
		    printer(arg, " %I", htonl(cilong));
		}
		break;
	    case CI_COMPRESSTYPE:
		if (olen >= CILEN_COMPRESS) {
		    p += 2;
		    GETSHORT(cishort, p);
		    printer(arg, "compress ");
		    switch (cishort) {
		    case IPCP_VJ_COMP:
			printer(arg, "VJ");
			break;
		    case IPCP_VJ_COMP_OLD:
			printer(arg, "old-VJ");
			break;
		    default:
			printer(arg, "0x%x", cishort);
		    }
		}
		break;
	    case CI_ADDR:
		if (olen == CILEN_ADDR) {
		    p += 2;
		    GETLONG(cilong, p);
		    printer(arg, "addr %I", htonl(cilong));
		}
		break;
	    case CI_MS_DNS1:
	    case CI_MS_DNS2:
	        p += 2;
		GETLONG(cilong, p);
		printer(arg, "ms-dns%d %I", code - CI_MS_DNS1 + 1,
			htonl(cilong));
		break;
	    case CI_MS_WINS1:
	    case CI_MS_WINS2:
	        p += 2;
		GETLONG(cilong, p);
		printer(arg, "ms-wins %I", htonl(cilong));
		break;
	    }
	    while (p < optend) {
		GETCHAR(code, p);
		printer(arg, " %.2x", code);
	    }
	    printer(arg, ">");
	}
	break;

    case TERMACK:
    case TERMREQ:
	if (len > 0 && *p >= ' ' && *p < 0x7f) {
	    printer(arg, " ");
	    print_string((char *)p, len, printer, arg);
	    p += len;
	    len = 0;
	}
	break;
    }

    /* print the rest of the bytes in the packet */
    for (; len > 0; --len) {
	GETCHAR(code, p);
	printer(arg, " %.2x", code);
    }

    return p - pstart;
}

/*
 * ip_active_pkt - see if this IP packet is worth bringing the link up for.
 * We don't bring the link up for IP fragments or for TCP FIN packets
 * with no data.
 */
#define IP_HDRLEN	20	/* bytes */
#define IP_OFFMASK	0x1fff
#ifndef IPPROTO_TCP
#define IPPROTO_TCP	6
#endif
#define TCP_HDRLEN	20
#define TH_FIN		0x01

/*
 * We use these macros because the IP header may be at an odd address,
 * and some compilers might use word loads to get th_off or ip_hl.
 */

#define net_short(x)	(((x)[0] << 8) + (x)[1])
#define get_iphl(x)	(((unsigned char *)(x))[0] & 0xF)
#define get_ipoff(x)	net_short((unsigned char *)(x) + 6)
#define get_ipproto(x)	(((unsigned char *)(x))[9])
#define get_tcpoff(x)	(((unsigned char *)(x))[12] >> 4)
#define get_tcpflags(x)	(((unsigned char *)(x))[13])

static int
ip_active_pkt(pkt, len)
    u_char *pkt;
    int len;
{
    u_char *tcp;
    int hlen;

    len -= PPP_HDRLEN;
    pkt += PPP_HDRLEN;
    if (len < IP_HDRLEN)
	return 0;
    if ((get_ipoff(pkt) & IP_OFFMASK) != 0)
	return 0;
    if (get_ipproto(pkt) != IPPROTO_TCP)
	return 1;
    hlen = get_iphl(pkt) * 4;
    if (len < hlen + TCP_HDRLEN)
	return 0;
    tcp = pkt + hlen;
    if ((get_tcpflags(tcp) & TH_FIN) != 0 && len == hlen + get_tcpoff(tcp) * 4)
	return 0;
    return 1;
}