: ,

1.

. Internet 4.294.967.296 , IP . . 璺 .

- , . 璺 , , , .

, 4- Internet 8-, 䒺 4.294.967.296 , , Internet.

, -, IP . 㳺, . IP , . , , 璺 . , , 璺. , .

- , . : , . , point-to-point. , (IP) , . , .

. .

1 / ᒺ .

57
24
26
18
20
34
28

1 : / ᒺ

, , , Interior Gateway Protocols: OSPF (Open Shortest Path First), Dual IS-IS (Intermediate System to Intermediate System), RIP (Routing Information Protocol), GGP (Gateway to Gateway Protocol); Exterior Gateway Protocols: BGP (Border Gateway Protocol), EGP (Exterior Gateway Protocol), Inter-AS Routing without Exterior Gateway; Static Routing.

Internet .

, ' . , . ( , -) o 񳺿  , . , .

³ , , . , , , . , . , .

Routed, RIP .

2.

2.1. RIP :

. ᒺ ( ), , . , , ᒺ, . , ᒺ. ³ - , , . , . , ᒺ, . -:

: IP IP ;

: ;

: , , ;

: , -;

: .

. ᒺ, 䒺 . , . , . ᒺ, , , . ᒺ.

(- , ) . , i j , d(i,j) i j. ᒺ , d(i,j) ᒺ . , , . , . D(i,j) i j. . d(i,j) . , d(i,j) , i j. , i j . ( , d(i,i) - . , , 璺 ). , :

D(i,i) = 0, i

D(i,j) = min [d(i,k) + D(k,j)], k

, i k, d(i,k) + D(k,j) .

k, i. d(i,k) , . . ᒺ i k ᒺ j. i d(k,j) k, d(k,j) D(i,k). .

, . , . , . , ᒺ, , - . ᒺ . , ᒺ 30 . ᒺ, , 180 ( ), .

2.2. OSPF, Dual IS-IS:

2.2.1. .

IP, OSI . ³ (N2).

, PATHS , PATHS ( SELF ). TENT .

PATHS , , , . N PATHS, M N N. N NM. <M,*,*> TENT , . <M,*,*> TENT , . <M,*,*> TENT , TENT {Adj(M)} (, TENT) - {Adj(N)}. M TENT, TENT.

<N,x,{Adj(N)}> in TENT x.

2.2.2. DUAL IS-IS

0: TENT PATHS . tentlength 0.

(tentlength TENT.)

1) <SELF,0,W> PATHS, SELF , W , SELF , .

2) TENT ( TENT OSI, 2).

Adj(N) :

d(N) = , (N)

Adj(N) = N.

3) <N,x,{Adj(M)}> TENT,

x = d(N), {Adj(M)} := {Adj(M)} U {Adj(N)}.

4) N OSI, {Adj(M)} .

5) x < d(N), .

6) x > d(N), <N,x,{Adj(M)}> TENT <N,d(N),{Adj(N)}>.

7) <N,x,{Adj(M)}> TENT, <N,d(N),{Adj(N)}> TENT.

8) , , LSP. .

9) , LSP . , N, TENT, :

<N,d(N),{Adj(N)}> to TENT, where:

d(N) = .

Adj(N) = , .

10) 2.

1: PDU LSP , PATHS

1)dist(P,N) = d(P) + metric.k(P,N) N ( , ) P.

2) dist(P,N) > , .

3) <N,d(N),{Adj(N)}> PATHS, .

d(N) dist(P,N), N PATHS. d(N) dist(P,N).

4) <N,x,{Adj(N)}> TENT, :

a) x = dist(P,N) {Adj(N)}:= {Adj(N)} U {Adj(P)}.

b) N OSI, {Adj(M)}, .

c) x < dist(P,N), .

d) x > dist(P,N), <N,x,{Adj(N)}> TENT, <N,dist(P,N),{Adj(P)}>

5) <N,x,{Adj(N)}> TENT, <N,dist(P,N),{Adj(P)}> TENT.

2: TENT , . :

1) <P,x,{Adj(P)}>, x :

a) <*,tentlength,*> TENT tentlength, . , , , , . tentlength, tentlength 2.

b) <P,tentlength,{Adj(P)}> TENT.

c) <P,d(P),{Adj(P)}> PATHS.

d) PATHS , 2. : 1.

:

PATHS S. ³ <N,d(N),{Adj(N)}>, N . d(N) N S).

{Adj(N)} S, N. PATHS, , .

TENT <N,d(N),{Adj(N)}>, N, d(N) {Adj(N)} PATHS.

TENT PATHS. , <N,x,{A}> TENT , , N PATHS, d(N) x, N PATHS , , x .

<N,x,{A,B}> TENT , N PATHS, d(N) x , A B.

TENT d(N).

3.

. Routed RIP. OSI TCP/IP - TCP/IP .

OSI , ISO

IS Interautonomous system , , OSI

ES - End System- , , OSI

Router , ᒺ

Gateway , ,

RIP (Routing Information Protocol)

OSPF (Open Shortest Path First)

C.L. Hedrick. Routing Information Protocol. RFC 1058 Jun-01-1988.

D. Waitzman, C.Partridge, S.E. Deering. Distance Vector Multicast Routing Protocol. RFC 1075 Nov-01-1988.

R.W. Callon. Use of OSI IS-IS for routing in TCP/IP and dual environments.

RFC 1195 Dec-01-1990.

P. Almquist, F. Kastenholz. Towards Requirements for IP Routers. RFC 1716 November 1994.

J. Moy. , OSPF Version 2. RFC 2178 July 1997.

A. Ballardie. Core Based Trees (CBT) Multicast Routing Architecture. RFC 2201September 1997.

Bellman, R. E., "Dynamic Programming", Princeton University Press, Princeton, N.J., 1957.

Bertsekas, D. P., and Gallaher, R. G., "Data Networks",Prentice-Hall, Englewood Cliffs, N.J., 1987.

Braden, R., and Postel, J., "Requirements for Internet Gateways", USC/Information Sciences Institute, RFC-1009, June 1987.

Boggs, D. R., Shoch, J. F., Taft, E. A., and Metcalfe, R. M.,"Pup: An Internetwork Architecture", IEEE Transactions on Communications, April 1980.

Clark, D. D., "Fault Isolation and Recovery," MIT-LCS, RFC-816, July 1982.

Xerox Corp., "Internet Transport Protocols", Xerox System Integration Standard XSIS 028112, December 1981.

Ford, L.R. Jr., and Fulkerson, D.R.,"Flows in Networks", Princeton University Press, Princeton, N.J., 1962.

"Intermediate System to Intermediate System Intra-Domain Routeing Exchange Protocol for use in Conjunction with the Protocol for Providing the Connectionless-mode Network Service (ISO 8473)", ISO DP 10589, February 1990.

"Protocol for Providing the Connectionless-Mode Network Service", ISO 8473, March 1987.

End System to Intermediate System Routeing Exchange Protocol for Use in Conjunction with the Protocol for Providing the Connectionless-Mode Network Service (ISO 8473)", ISO 9542, March 1988.

Braden,R., and Postel,J., "Requirements for Internet Gateways", RFC 1009, June 1987.

Moy,J., "The OSPF Specification", RFC 1131, October 1989.

Postel,J., "Internetwork Protocol", RFC 791, September 1981.

Postel,J., "Internet Control Message Protocol", RFC 792, September 1981.

20. GOSIP Advanced Requirements Group, "Government Open Systems

Interconnection Profile (GOSIP) Version 2.0 [Final Text]", Federal Information Processing Standard, U.S. Department of Commerce, National Institute of Standards and Technology, Gaithersburg, MD, October 1990.

21. "Standard for Local Area Networks and Metropolitan Area Networks: Overview and Architecture of Network Standards",IEEE Standard 802.1a-1990.

#include "defs.h"

#include "pathnames.h"

#ifdef sgi

#include "math.h"

#endif

#include <signal.h>

#include <fcntl.h>

#include <sys/file.h>

pid_t mypid;

naddr myaddr; /* system address */

char myname[MAXHOSTNAMELEN+1];

int supplier; /* supply or broadcast updates */

int supplier_set;

int ipforwarding = 1; /* kernel forwarding on */

int default_gateway; /* 1=advertise default */

int background = 1;

int ridhosts; /* 1=reduce host routes */

int mhome; /* 1=want multi-homed host route */

int advertise_mhome; /* 1=must continue adverising it */

int auth_ok = 1; /* 1=ignore auth if we do not care */

struct timeval epoch; /* when started */

struct timeval clk, prev_clk;

struct timeval now; /* current idea of time */

time_t now_stale;

time_t now_expire;

time_t now_garbage;

struct timeval next_bcast; /* next general broadcast */

struct timeval no_flash = {EPOCH+SUPPLY_INTERVAL}; /* inhibit flash update */

fd_set fdbits;

int sock_max;

int rip_sock = -1; /* RIP socket */

struct interface *rip_sock_mcast; /* current multicast interface */

int rt_sock; /* routing socket */

int rt_sock_seqno;

static int get_rip_sock(naddr, int);

static void timevalsub(struct timeval *, struct timeval *, struct timeval *);

int

main(int argc,

char *argv[])

{

int n, mib[4], off;

size_t len;

char *p, *q;

struct timeval wtime, t2;

time_t dt;

fd_set ibits;

naddr p_net, p_mask;

struct interface *ifp;

struct parm parm;

char *tracename = 0;

/* Some shells are badly broken and send SIGHUP to backgrounded

* processes.

*/

signal(SIGHUP, SIG_IGN);

openlog("routed", LOG_PID | LOG_ODELAY, LOG_DAEMON);

ftrace = stdout;

gettimeofday(&clk, 0);

prev_clk = clk;

epoch = clk;

epoch.tv_sec -= EPOCH;

now.tv_sec = EPOCH;

now_stale = EPOCH - STALE_TIME;

now_expire = EPOCH - EXPIRE_TIME;

now_garbage = EPOCH - GARBAGE_TIME;

wtime.tv_sec = 0;

(void)gethostname(myname, sizeof(myname)-1);

(void)gethost(myname, &myaddr);

while ((n = getopt(argc, argv, "sqdghmAtT:F:P:")) != -1) {

switch (n) {

case 's':

supplier = 1;

supplier_set = 1;

break;

case 'q':

supplier = 0;

supplier_set = 1;

break;

case 'd':

background = 0;

break;

case 'g':

bzero(&parm, sizeof(parm));

parm.parm_d_metric = 1;

p = check_parms(&parm);

if (p != 0)

msglog("bad -g: %s", p);

else

default_gateway = 1;

break;

case 'h': /* suppress extra host routes */

ridhosts = 1;

break;

case 'm': /* advertise host route */

mhome = 1; /* on multi-homed hosts */

break;

case 'A':

/* Ignore authentication if we do not care.

* Crazy as it is, that is what RFC 1723 requires.

*/

auth_ok = 0;

break;

case 't':

new_tracelevel++;

break;

case 'T':

tracename = optarg;

break;

case 'F': /* minimal routes for SLIP */

n = FAKE_METRIC;

p = strchr(optarg,',');

if (p && *p != '\0') {

n = (int)strtoul(p+1, &q, 0);

if (*q == '\0'

&& n <= HOPCNT_INFINITY-1

&& n >= 1)

*p = '\0';

}

if (!getnet(optarg, &p_net, &p_mask)) {

msglog("bad network; \"-F %s\"",

optarg);

break;

}

bzero(&parm, sizeof(parm));

parm.parm_net = p_net;

parm.parm_mask = p_mask;

parm.parm_d_metric = n;

p = check_parms(&parm);

if (p != 0)

msglog("bad -F: %s", p);

break;

case 'P':

/* handle arbirary, (usually) per-interface

* parameters.

*/

p = parse_parms(optarg, 0);

if (p != 0) {

if (strcasecmp(p,optarg))

msglog("%s in \"%s\"", p, optarg);

else

msglog("bad \"-P %s\"", optarg);

}

break;

default:

goto usage;

}

}

argc -= optind;

argv += optind;

if (tracename == 0 && argc >= 1) {

tracename = *argv++;

argc--;

}

if (tracename != 0 && tracename[0] == '\0')

goto usage;

if (argc != 0) {

usage:

logbad(0, "usage: routed [-sqdghmAt] [-T tracefile]"

" [-F net[/mask[,metric]]] [-P parms]");

}

if (geteuid() != 0)

logbad(0, "requires UID 0");

mib[0] = CTL_NET;

mib[1] = PF_INET;

mib[2] = IPPROTO_IP;

mib[3] = IPCTL_FORWARDING;

len = sizeof(ipforwarding);

if (sysctl(mib, 4, &ipforwarding, &len, 0, 0) < 0)

LOGERR("sysctl(IPCTL_FORWARDING)");

if (!ipforwarding) {

if (supplier)

msglog("-s incompatible with ipforwarding=0");

if (default_gateway) {

msglog("-g incompatible with ipforwarding=0");

default_gateway = 0;

}

supplier = 0;

supplier_set = 1;

}

if (default_gateway) {

if (supplier_set && !supplier) {

msglog("-g and -q incompatible");

} else {

supplier = 1;

supplier_set = 1;

}

}

signal(SIGALRM, sigalrm);

if (!background)

signal(SIGHUP, sigterm); /* SIGHUP fatal during debugging */

signal(SIGTERM, sigterm);

signal(SIGINT, sigterm);

signal(SIGUSR1, sigtrace_on);

signal(SIGUSR2, sigtrace_off);

/* get into the background */

#ifdef sgi

if (0 > _daemonize(background ? 0 : (_DF_NOCHDIR|_DF_NOFORK),

new_tracelevel == 0 ? -1 : STDOUT_FILENO,

new_tracelevel == 0 ? -1 : STDERR_FILENO,

-1))

BADERR(0, "_daemonize()");

#else

if (background && daemon(0, new_tracelevel) < 0)

BADERR(0,"daemon()");

#endif

mypid = getpid();

srandom((int)(clk.tv_sec ^ clk.tv_usec ^ mypid));

/* prepare socket connected to the kernel.

*/

rt_sock = socket(AF_ROUTE, SOCK_RAW, 0);

if (rt_sock < 0)

BADERR(1,"rt_sock = socket()");

if (fcntl(rt_sock, F_SETFL, O_NONBLOCK) == -1)

logbad(1, "fcntl(rt_sock) O_NONBLOCK: %s", strerror(errno));

off = 0;

if (setsockopt(rt_sock, SOL_SOCKET,SO_USELOOPBACK,

&off,sizeof(off)) < 0)

LOGERR("setsockopt(SO_USELOOPBACK,0)");

fix_select();

if (background && new_tracelevel == 0)

ftrace = 0;

if (tracename != 0) {

strncpy(inittracename, tracename, sizeof(inittracename)-1);

set_tracefile(inittracename, "%s\n", -1);

} else {

tracelevel_msg("%s\n", -1); /* turn on tracing to stdio */

}

bufinit();

/* initialize radix tree */

rtinit();

/* Pick a random part of the second for our output to minimize

* collisions.

*

* Start broadcasting after hearing from other routers, and

* at a random time so a bunch of systems do not get synchronized

* after a power failure.

*/

intvl_random(&next_bcast, EPOCH+MIN_WAITTIME, EPOCH+SUPPLY_INTERVAL);

age_timer.tv_usec = next_bcast.tv_usec;

age_timer.tv_sec = EPOCH+MIN_WAITTIME;

rdisc_timer = next_bcast;

ifinit_timer.tv_usec = next_bcast.tv_usec;

/* Collect an initial view of the world by checking the interface

* configuration and the kludge file.

*/

gwkludge();

ifinit();

flush_kern();

/* Ask for routes */

rip_query();

rdisc_sol();

/* Loop forever, listening and broadcasting.

*/

for (;;) {

prev_clk = clk;

gettimeofday(&clk, 0);

timevalsub(&t2, &clk, &prev_clk);

if (t2.tv_sec < 0

|| t2.tv_sec > wtime.tv_sec + 5) {

/* Deal with time changes before other housekeeping to

* keep everything straight.

*/

dt = t2.tv_sec;

if (dt > 0)

dt -= wtime.tv_sec;

trace_act("time changed by %d sec", dt);

epoch.tv_sec += dt;

}

timevalsub(&now, &clk, &epoch);

now_stale = now.tv_sec - STALE_TIME;

now_expire = now.tv_sec - EXPIRE_TIME;

now_garbage = now.tv_sec - GARBAGE_TIME;

/* deal with signals that should affect tracing */

set_tracelevel();

if (stopint != 0) {

rip_bcast(0);

rdisc_adv();

trace_off("exiting with signal %d\n", stopint);

exit(stopint | 128);

}

/* look for new or dead interfaces */

timevalsub(&wtime, &ifinit_timer, &now);

if (wtime.tv_sec <= 0) {

wtime.tv_sec = 0;

ifinit();

rip_query();

continue;

}

/* If it is time, then broadcast our routes.

*/

if (supplier || advertise_mhome) {

timevalsub(&t2, &next_bcast, &now);

if (t2.tv_sec <= 0) {

/* Synchronize the aging and broadcast

* timers to minimize awakenings

*/

age(0);

rip_bcast(0);

/* It is desirable to send routing updates

* regularly. So schedule the next update

* 30 seconds after the previous one was

* secheduled, instead of 30 seconds after

* the previous update was finished.

* Even if we just started after discovering

* a 2nd interface or were otherwise delayed,

* pick a 30-second aniversary of the

* original broadcast time.

*/

n = 1 + (0-t2.tv_sec)/SUPPLY_INTERVAL;

next_bcast.tv_sec += n*SUPPLY_INTERVAL;

continue;

}

if (timercmp(&t2, &wtime, <))

wtime = t2;

}

/* If we need a flash update, either do it now or

* set the delay to end when it is time.

*

* If we are within MIN_WAITTIME seconds of a full update,

* do not bother.

*/

if (need_flash

&& supplier

&& no_flash.tv_sec+MIN_WAITTIME < next_bcast.tv_sec) {

/* accurate to the millisecond */

if (!timercmp(&no_flash, &now, >))

rip_bcast(1);

timevalsub(&t2, &no_flash, &now);

if (timercmp(&t2, &wtime, <))

wtime = t2;

}

/* trigger the main aging timer.

*/

timevalsub(&t2, &age_timer, &now);

if (t2.tv_sec <= 0) {

age(0);

continue;

}

if (timercmp(&t2, &wtime, <))

wtime = t2;

/* update the kernel routing table

*/

timevalsub(&t2, &need_kern, &now);

if (t2.tv_sec <= 0) {

age(0);

continue;

}

if (timercmp(&t2, &wtime, <))

wtime = t2;

/* take care of router discovery,

* but do it to the millisecond

*/

if (!timercmp(&rdisc_timer, &now, >)) {

rdisc_age(0);

continue;

}

timevalsub(&t2, &rdisc_timer, &now);

if (timercmp(&t2, &wtime, <))

wtime = t2;

/* wait for input or a timer to expire.

*/

trace_flush();

ibits = fdbits;

n = select(sock_max, &ibits, 0, 0, &wtime);

if (n <= 0) {

if (n < 0 && errno != EINTR && errno != EAGAIN)

BADERR(1,"select");

continue;

}

if (FD_ISSET(rt_sock, &ibits)) {

read_rt();

n--;

}

if (rdisc_sock >= 0 && FD_ISSET(rdisc_sock, &ibits)) {

read_d();

n--;

}

if (rip_sock >= 0 && FD_ISSET(rip_sock, &ibits)) {

read_rip(rip_sock, 0);

n--;

}

for (ifp = ifnet; n > 0 && 0 != ifp; ifp = ifp->int_next) {

if (ifp->int_rip_sock >= 0

&& FD_ISSET(ifp->int_rip_sock, &ibits)) {

read_rip(ifp->int_rip_sock, ifp);

n--;

}

}

}

}

/* ARGSUSED */

void

sigalrm(int s)

{

/* Historically, SIGALRM would cause the daemon to check for

* new and broken interfaces.

*/

ifinit_timer.tv_sec = now.tv_sec;

trace_act("SIGALRM");

}

/* watch for fatal signals */

void

sigterm(int sig)

{

stopint = sig;

(void)signal(sig, SIG_DFL); /* catch it only once */

}

void

fix_select(void)

{

struct interface *ifp;

FD_ZERO(&fdbits);

sock_max = 0;

FD_SET(rt_sock, &fdbits);

if (sock_max <= rt_sock)

sock_max = rt_sock+1;

if (rip_sock >= 0) {

FD_SET(rip_sock, &fdbits);

if (sock_max <= rip_sock)

sock_max = rip_sock+1;

}

for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next) {

if (ifp->int_rip_sock >= 0) {

FD_SET(ifp->int_rip_sock, &fdbits);

if (sock_max <= ifp->int_rip_sock)

sock_max = ifp->int_rip_sock+1;

}

}

if (rdisc_sock >= 0) {

FD_SET(rdisc_sock, &fdbits);

if (sock_max <= rdisc_sock)

sock_max = rdisc_sock+1;

}

}

void

fix_sock(int sock,

char *name)

{

int on;

#define MIN_SOCKBUF (4*1024)

static int rbuf;

if (fcntl(sock, F_SETFL, O_NONBLOCK) == -1)

logbad(1, "fcntl(%s) O_NONBLOCK: %s",

name, strerror(errno));

on = 1;

if (setsockopt(sock, SOL_SOCKET,SO_BROADCAST, &on,sizeof(on)) < 0)

msglog("setsockopt(%s,SO_BROADCAST): %s",

name, strerror(errno));

#ifdef USE_PASSIFNAME

on = 1;

if (setsockopt(sock, SOL_SOCKET, SO_PASSIFNAME, &on,sizeof(on)) < 0)

msglog("setsockopt(%s,SO_PASSIFNAME): %s",

name, strerror(errno));

#endif

if (rbuf >= MIN_SOCKBUF) {

if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF,

&rbuf, sizeof(rbuf)) < 0)

msglog("setsockopt(%s,SO_RCVBUF=%d): %s",

name, rbuf, strerror(errno));

} else {

for (rbuf = 60*1024; ; rbuf -= 4096) {

if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF,

&rbuf, sizeof(rbuf)) == 0) {

trace_act("RCVBUF=%d", rbuf);

break;

}

if (rbuf < MIN_SOCKBUF) {

msglog("setsockopt(%s,SO_RCVBUF = %d): %s",

name, rbuf, strerror(errno));

break;

}

}

}

}

/* get a rip socket

*/

static int /* <0 or file descriptor */

get_rip_sock(naddr addr,

int serious) /* 1=failure to bind is serious */

{

struct sockaddr_in sin;

unsigned char ttl;

int s;

if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)

BADERR(1,"rip_sock = socket()");

bzero(&sin,sizeof(sin));

#ifdef _HAVE_SIN_LEN

sin.sin_len = sizeof(sin);

#endif

sin.sin_family = AF_INET;

sin.sin_port = htons(RIP_PORT);

sin.sin_addr.s_addr = addr;

if (bind(s, (struct sockaddr *)&sin,sizeof(sin)) < 0) {

if (serious)

BADERR(errno != EADDRINUSE, "bind(rip_sock)");

return -1;

}

fix_sock(s,"rip_sock");

ttl = 1;

if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL,

&ttl, sizeof(ttl)) < 0)

DBGERR(1,"rip_sock setsockopt(IP_MULTICAST_TTL)");

return s;

}

/* turn off main RIP socket */

void

rip_off(void)

{

struct interface *ifp;

register naddr addr;

if (rip_sock >= 0 && !mhome) {

trace_act("turn off RIP");

(void)close(rip_sock);

rip_sock = -1;

/* get non-broadcast sockets to listen to queries.

*/

for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {

if (ifp->int_state & IS_REMOTE)

continue;

if (ifp->int_rip_sock < 0) {

addr = ((ifp->int_if_flags & IFF_POINTOPOINT)

? ifp->int_dstaddr

: ifp->int_addr);

ifp->int_rip_sock = get_rip_sock(addr, 0);

}

}

fix_select();

age(0);

}

}

/* turn on RIP multicast input via an interface

*/

static void

rip_mcast_on(struct interface *ifp)

{

struct ip_mreq m;

if (!IS_RIP_IN_OFF(ifp->int_state)

&& (ifp->int_if_flags & IFF_MULTICAST)

#ifdef MCAST_PPP_BUG

&& !(ifp->int_if_flags & IFF_POINTOPOINT)

#endif

&& !(ifp->int_state & IS_ALIAS)) {

m.imr_multiaddr.s_addr = htonl(INADDR_RIP_GROUP);

m.imr_interface.s_addr = ((ifp->int_if_flags & IFF_POINTOPOINT)

? ifp->int_dstaddr

: ifp->int_addr);

if (setsockopt(rip_sock,IPPROTO_IP, IP_ADD_MEMBERSHIP,

&m, sizeof(m)) < 0)

LOGERR("setsockopt(IP_ADD_MEMBERSHIP RIP)");

}

}

/* Prepare socket used for RIP.

*/

void

rip_on(struct interface *ifp)

{

/* If the main RIP socket is already alive, only start receiving

* multicasts for this interface.

*/

if (rip_sock >= 0) {

if (ifp != 0)

rip_mcast_on(ifp);

return;

}

/* If the main RIP socket is off and it makes sense to turn it on,

* then turn it on for all of the interfaces.

*/

if (rip_interfaces > 0 && !rdisc_ok) {

trace_act("turn on RIP");

/* Close all of the query sockets so that we can open

* the main socket. SO_REUSEPORT is not a solution,

* since that would let two daemons bind to the broadcast

* socket.

*/

for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {

if (ifp->int_rip_sock >= 0) {

(void)close(ifp->int_rip_sock);

ifp->int_rip_sock = -1;

}

}

rip_sock = get_rip_sock(INADDR_ANY, 1);

rip_sock_mcast = 0;

/* Do not advertise anything until we have heard something

*/

if (next_bcast.tv_sec < now.tv_sec+MIN_WAITTIME)

next_bcast.tv_sec = now.tv_sec+MIN_WAITTIME;

for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {

ifp->int_query_time = NEVER;

rip_mcast_on(ifp);

}

ifinit_timer.tv_sec = now.tv_sec;

} else if (ifp != 0

&& !(ifp->int_state & IS_REMOTE)

&& ifp->int_rip_sock < 0) {

/* RIP is off, so ensure there are sockets on which

* to listen for queries.

*/

ifp->int_rip_sock = get_rip_sock(ifp->int_addr, 0);

}

fix_select();

}

/* die if malloc(3) fails

*/

void *

rtmalloc(size_t size,

char *msg)

{

void *p = malloc(size);

if (p == 0)

logbad(1,"malloc() failed in %s", msg);

return p;

}

/* get a random instant in an interval

*/

void

intvl_random(struct timeval *tp, /* put value here */

u_long lo, /* value is after this second */

u_long hi) /* and before this */

{

tp->tv_sec = (time_t)(hi == lo

? lo

: (lo + random() % ((hi - lo))));

tp->tv_usec = random() % 1000000;

}

void

timevaladd(struct timeval *t1,

struct timeval *t2)

{

t1->tv_sec += t2->tv_sec;

if ((t1->tv_usec += t2->tv_usec) > 1000000) {

t1->tv_sec++;

t1->tv_usec -= 1000000;

}

}

/* t1 = t2 - t3

*/

static void

timevalsub(struct timeval *t1,

struct timeval *t2,

struct timeval *t3)

{

t1->tv_sec = t2->tv_sec - t3->tv_sec;

if ((t1->tv_usec = t2->tv_usec - t3->tv_usec) < 0) {

t1->tv_sec--;

t1->tv_usec += 1000000;

}

}

/* put a message into the system log

*/

void

msglog(char *p, ...)

{

va_list args;

trace_flush();

va_start(args, p);

vsyslog(LOG_ERR, p, args);

if (ftrace != 0) {

if (ftrace == stdout)

(void)fputs("routed: ", ftrace);

(void)vfprintf(ftrace, p, args);

(void)fputc('\n', ftrace);

}

}

/* Put a message about a bad system into the system log if

* we have not complained about it recently.

*

* It is desirable to complain about all bad systems, but not too often.

* In the worst case, it is not practical to keep track of all bad systems.

* For example, there can be many systems with the wrong password.

*/

void

msglim(struct msg_limit *lim, naddr addr, char *p, ...)

{

va_list args;

int i;

struct msg_sub *ms1, *ms;

char *p1;

va_start(args, p);

/* look for the oldest slot in the table

* or the slot for the bad router.

*/

ms = ms1 = lim->subs;

for (i = MSG_SUBJECT_N; ; i--, ms1++) {

if (i == 0) {

/* Reuse a slot at most once every 10 minutes.

*/

if (lim->reuse > now.tv_sec) {

ms = 0;

} else {

ms = ms1;

lim->reuse = now.tv_sec + 10*60;

}

break;

}

if (ms->addr == addr) {

/* Repeat a complaint about a given system at

* most once an hour.

*/

if (ms->until > now.tv_sec)

ms = 0;

break;

}

if (ms->until < ms1->until)

ms = ms1;

}

if (ms != 0) {

ms->addr = addr;

ms->until = now.tv_sec + 60*60; /* 60 minutes */

trace_flush();

for (p1 = p; *p1 == ' '; p1++)

continue;

vsyslog(LOG_ERR, p1, args);

}

/* always display the message if tracing */

if (ftrace != 0) {

(void)vfprintf(ftrace, p, args);

(void)fputc('\n', ftrace);

}

}

void

logbad(int dump, char *p, ...)

{

va_list args;

trace_flush();

va_start(args, p);

vsyslog(LOG_ERR, p, args);

(void)fputs("routed: ", stderr);

(void)vfprintf(stderr, p, args);

(void)fputs("; giving up\n",stderr);

(void)fflush(stderr);

if (dump)

abort();

exit(1);

}

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