📄 lcp.c
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fsm_sdata(&lcp_fsm[unit], PROTREJ, ++lcp_fsm[unit].id,
p, len);
}
/*
* lcp_resetci - Reset our CI.
*/
static void
lcp_resetci(f)
fsm *f;
{
lcp_wantoptions[f->unit].magicnumber = magic();
lcp_wantoptions[f->unit].numloops = 0;
lcp_gotoptions[f->unit] = lcp_wantoptions[f->unit];
peer_mru[f->unit] = PPP_MRU;
auth_reset(f->unit);
}
/*
* lcp_cilen - Return length of our CI.
*/
static int
lcp_cilen(f)
fsm *f;
{
lcp_options *go = &lcp_gotoptions[f->unit];
#define LENCIVOID(neg) ((neg) ? CILEN_VOID : 0)
#define LENCICHAP(neg) ((neg) ? CILEN_CHAP : 0)
#define LENCISHORT(neg) ((neg) ? CILEN_SHORT : 0)
#define LENCILONG(neg) ((neg) ? CILEN_LONG : 0)
#define LENCILQR(neg) ((neg) ? CILEN_LQR: 0)
#define LENCICBCP(neg) ((neg) ? CILEN_CBCP: 0)
/*
* NB: we only ask for one of CHAP and UPAP, even if we will
* accept either.
*/
return (LENCISHORT(go->neg_mru && go->mru != DEFMRU) +
LENCILONG(go->neg_asyncmap && go->asyncmap != 0xFFFFFFFF) +
LENCICHAP(go->neg_chap) +
LENCISHORT(!go->neg_chap && go->neg_upap) +
LENCILQR(go->neg_lqr) +
LENCICBCP(go->neg_cbcp) +
LENCILONG(go->neg_magicnumber) +
LENCIVOID(go->neg_pcompression) +
LENCIVOID(go->neg_accompression));
}
/*
* lcp_addci - Add our desired CIs to a packet.
*/
static void
lcp_addci(f, ucp, lenp)
fsm *f;
u_char *ucp;
int *lenp;
{
lcp_options *go = &lcp_gotoptions[f->unit];
u_char *start_ucp = ucp;
#define ADDCIVOID(opt, neg) \ if (neg) { \ PUTCHAR(opt, ucp); \ PUTCHAR(CILEN_VOID, ucp); \ }
#define ADDCISHORT(opt, neg, val) \ if (neg) { \ PUTCHAR(opt, ucp); \ PUTCHAR(CILEN_SHORT, ucp); \ PUTSHORT(val, ucp); \ }
#define ADDCICHAP(opt, neg, val, digest) \ if (neg) { \ PUTCHAR(opt, ucp); \ PUTCHAR(CILEN_CHAP, ucp); \ PUTSHORT(val, ucp); \ PUTCHAR(digest, ucp); \ }
#define ADDCILONG(opt, neg, val) \ if (neg) { \ PUTCHAR(opt, ucp); \ PUTCHAR(CILEN_LONG, ucp); \ PUTLONG(val, ucp); \ }
#define ADDCILQR(opt, neg, val) \ if (neg) { \ PUTCHAR(opt, ucp); \ PUTCHAR(CILEN_LQR, ucp); \ PUTSHORT(PPP_LQR, ucp); \ PUTLONG(val, ucp); \ }
#define ADDCICHAR(opt, neg, val) \ if (neg) { \ PUTCHAR(opt, ucp); \ PUTCHAR(CILEN_CHAR, ucp); \ PUTCHAR(val, ucp); \ }
ADDCISHORT(CI_MRU, go->neg_mru && go->mru != DEFMRU, go->mru);
ADDCILONG(CI_ASYNCMAP, go->neg_asyncmap && go->asyncmap != 0xFFFFFFFF,
go->asyncmap);
ADDCICHAP(CI_AUTHTYPE, go->neg_chap, PPP_CHAP, go->chap_mdtype);
ADDCISHORT(CI_AUTHTYPE, !go->neg_chap && go->neg_upap, PPP_PAP);
ADDCILQR(CI_QUALITY, go->neg_lqr, go->lqr_period);
ADDCICHAR(CI_CALLBACK, go->neg_cbcp, CBCP_OPT);
ADDCILONG(CI_MAGICNUMBER, go->neg_magicnumber, go->magicnumber);
ADDCIVOID(CI_PCOMPRESSION, go->neg_pcompression);
ADDCIVOID(CI_ACCOMPRESSION, go->neg_accompression);
if (ucp - start_ucp != *lenp) {
/* this should never happen, because peer_mtu should be 1500 */
syslog(LOG_ERR, "Bug in lcp_addci: wrong length");
}
}
/*
* lcp_ackci - Ack our CIs.
* This should not modify any state if the Ack is bad.
*
* Returns:
* 0 - Ack was bad.
* 1 - Ack was good.
*/
static int
lcp_ackci(f, p, len)
fsm *f;
u_char *p;
int len;
{
lcp_options *go = &lcp_gotoptions[f->unit];
u_char cilen, citype, cichar;
u_short cishort;
u_int32_t cilong;
/*
* CIs must be in exactly the same order that we sent.
* Check packet length and CI length at each step.
* If we find any deviations, then this packet is bad.
*/
#define ACKCIVOID(opt, neg) \ if (neg) { \ if ((len -= CILEN_VOID) < 0) \ goto bad; \ GETCHAR(citype, p); \ GETCHAR(cilen, p); \ if (cilen != CILEN_VOID || \ citype != opt) \ goto bad; \ }
#define ACKCISHORT(opt, neg, val) \ if (neg) { \ if ((len -= CILEN_SHORT) < 0) \ goto bad; \ GETCHAR(citype, p); \ GETCHAR(cilen, p); \ if (cilen != CILEN_SHORT || \ citype != opt) \ goto bad; \ GETSHORT(cishort, p); \ if (cishort != val) \ goto bad; \ }
#define ACKCICHAR(opt, neg, val) \ if (neg) { \ if ((len -= CILEN_CHAR) < 0) \ goto bad; \ GETCHAR(citype, p); \ GETCHAR(cilen, p); \ if (cilen != CILEN_CHAR || \ citype != opt) \ goto bad; \ GETCHAR(cichar, p); \ if (cichar != val) \ goto bad; \ }
#define ACKCICHAP(opt, neg, val, digest) \ if (neg) { \ if ((len -= CILEN_CHAP) < 0) \ goto bad; \ GETCHAR(citype, p); \ GETCHAR(cilen, p); \ if (cilen != CILEN_CHAP || \ citype != opt) \ goto bad; \ GETSHORT(cishort, p); \ if (cishort != val) \ goto bad; \ GETCHAR(cichar, p); \ if (cichar != digest) \ goto bad; \ }
#define ACKCILONG(opt, neg, val) \ if (neg) { \ if ((len -= CILEN_LONG) < 0) \ goto bad; \ GETCHAR(citype, p); \ GETCHAR(cilen, p); \ if (cilen != CILEN_LONG || \ citype != opt) \ goto bad; \ GETLONG(cilong, p); \ if (cilong != val) \ goto bad; \ }
#define ACKCILQR(opt, neg, val) \ if (neg) { \ if ((len -= CILEN_LQR) < 0) \ goto bad; \ GETCHAR(citype, p); \ GETCHAR(cilen, p); \ if (cilen != CILEN_LQR || \ citype != opt) \ goto bad; \ GETSHORT(cishort, p); \ if (cishort != PPP_LQR) \ goto bad; \ GETLONG(cilong, p); \ if (cilong != val) \ goto bad; \ }
ACKCISHORT(CI_MRU, go->neg_mru && go->mru != DEFMRU, go->mru);
ACKCILONG(CI_ASYNCMAP, go->neg_asyncmap && go->asyncmap != 0xFFFFFFFF,
go->asyncmap);
ACKCICHAP(CI_AUTHTYPE, go->neg_chap, PPP_CHAP, go->chap_mdtype);
ACKCISHORT(CI_AUTHTYPE, !go->neg_chap && go->neg_upap, PPP_PAP);
ACKCILQR(CI_QUALITY, go->neg_lqr, go->lqr_period);
ACKCICHAR(CI_CALLBACK, go->neg_cbcp, CBCP_OPT);
ACKCILONG(CI_MAGICNUMBER, go->neg_magicnumber, go->magicnumber);
ACKCIVOID(CI_PCOMPRESSION, go->neg_pcompression);
ACKCIVOID(CI_ACCOMPRESSION, go->neg_accompression);
/*
* If there are any remaining CIs, then this packet is bad.
*/
if (len != 0)
goto bad;
return (1);
bad:
LCPDEBUG((LOG_WARNING, "lcp_acki: received bad Ack!"));
return (0);
}
/*
* lcp_nakci - Peer has sent a NAK for some of our CIs.
* This should not modify any state if the Nak is bad
* or if LCP is in the OPENED state.
*
* Returns:
* 0 - Nak was bad.
* 1 - Nak was good.
*/
static int
lcp_nakci(f, p, len)
fsm *f;
u_char *p;
int len;
{
lcp_options *go = &lcp_gotoptions[f->unit];
lcp_options *wo = &lcp_wantoptions[f->unit];
u_char citype, cichar, *next;
u_short cishort;
u_int32_t cilong;
lcp_options no; /* options we've seen Naks for */
lcp_options try; /* options to request next time */
int looped_back = 0;
int cilen;
BZERO(&no, sizeof(no));
try = *go;
/*
* Any Nak'd CIs must be in exactly the same order that we sent.
* Check packet length and CI length at each step.
* If we find any deviations, then this packet is bad.
*/
#define NAKCIVOID(opt, neg, code) \ if (go->neg && \ len >= CILEN_VOID && \ p[1] == CILEN_VOID && \ p[0] == opt) { \ len -= CILEN_VOID; \ INCPTR(CILEN_VOID, p); \ no.neg = 1; \ code \ }
#define NAKCICHAP(opt, neg, code) \ if (go->neg && \ len >= CILEN_CHAP && \ p[1] == CILEN_CHAP && \ p[0] == opt) { \ len -= CILEN_CHAP; \ INCPTR(2, p); \ GETSHORT(cishort, p); \ GETCHAR(cichar, p); \ no.neg = 1; \ code \ }
#define NAKCICHAR(opt, neg, code) \ if (go->neg && \ len >= CILEN_CHAR && \ p[1] == CILEN_CHAR && \ p[0] == opt) { \ len -= CILEN_CHAR; \ INCPTR(2, p); \ GETCHAR(cichar, p); \ no.neg = 1; \ code \ }
#define NAKCISHORT(opt, neg, code) \ if (go->neg && \ len >= CILEN_SHORT && \ p[1] == CILEN_SHORT && \ p[0] == opt) { \ len -= CILEN_SHORT; \ INCPTR(2, p); \ GETSHORT(cishort, p); \ no.neg = 1; \ code \ }
#define NAKCILONG(opt, neg, code) \ if (go->neg && \ len >= CILEN_LONG && \ p[1] == CILEN_LONG && \ p[0] == opt) { \ len -= CILEN_LONG; \ INCPTR(2, p); \ GETLONG(cilong, p); \ no.neg = 1; \ code \ }
#define NAKCILQR(opt, neg, code) \ if (go->neg && \ len >= CILEN_LQR && \ p[1] == CILEN_LQR && \ p[0] == opt) { \ len -= CILEN_LQR; \ INCPTR(2, p); \ GETSHORT(cishort, p); \ GETLONG(cilong, p); \ no.neg = 1; \ code \ }
/*
* We don't care if they want to send us smaller packets than
* we want. Therefore, accept any MRU less than what we asked for,
* but then ignore the new value when setting the MRU in the kernel.
* If they send us a bigger MRU than what we asked, accept it, up to
* the limit of the default MRU we'd get if we didn't negotiate.
*/
if (go->neg_mru && go->mru != DEFMRU) {
NAKCISHORT(CI_MRU, neg_mru,
if (cishort <= wo->mru || cishort <= DEFMRU)
try.mru = cishort;
);
}
/*
* Add any characters they want to our (receive-side) asyncmap.
*/
if (go->neg_asyncmap && go->asyncmap != 0xFFFFFFFF) {
NAKCILONG(CI_ASYNCMAP, neg_asyncmap,
try.asyncmap = go->asyncmap | cilong;
);
}
/*
* If they've nak'd our authentication-protocol, check whether
* they are proposing a different protocol, or a different
* hash algorithm for CHAP.
*/
if ((go->neg_chap || go->neg_upap)
&& len >= CILEN_SHORT
&& p[0] == CI_AUTHTYPE && p[1] >= CILEN_SHORT && p[1] <= len) {
cilen = p[1];
len -= cilen;
no.neg_chap = go->neg_chap;
no.neg_upap = go->neg_upap;
INCPTR(2, p);
GETSHORT(cishort, p);
if (cishort == PPP_PAP && cilen == CILEN_SHORT) {
/*
* If we were asking for CHAP, they obviously don't want to do it.
* If we weren't asking for CHAP, then we were asking for PAP,
* in which case this Nak is bad.
*/
if (!go->neg_chap)
goto bad;
try.neg_chap = 0;
} else if (cishort == PPP_CHAP && cilen == CILEN_CHAP) {
GETCHAR(cichar, p);
if (go->neg_chap) {
/*
* We were asking for CHAP/MD5; they must want a different
* algorithm. If they can't do MD5, we'll have to stop
* asking for CHAP.
*/
if (cichar != go->chap_mdtype)
try.neg_chap = 0;
} else {
/*
* Stop asking for PAP if we were asking for it.
*/
try.neg_upap = 0;
}
} else {
/*
* We don't recognize what they're suggesting.
* Stop asking for what we were asking for.
*/
if (go->neg_chap)
try.neg_chap = 0;
else
try.neg_upap = 0;
p += cilen - CILEN_SHORT;
}
}
/*
* If they can't cope with our link quality protocol, we'll have
* to stop asking for LQR. We haven't got any other protocol.
* If they Nak the reporting period, take their value XXX ?
*/
NAKCILQR(CI_QUALITY, neg_lqr,
if (cishort != PPP_LQR)
try.neg_lqr = 0;
else
try.lqr_period = cilong;
);
/*
* Only implementing CBCP...not the rest of the callback options
*/
NAKCICHAR(CI_CALLBACK, neg_cbcp,
try.neg_cbcp = 0;
);
/*
* Check for a looped-back line.
*/
NAKCILONG(CI_MAGICNUMBER, neg_magicnumber,
try.magicnumber = magic();
looped_back = 1;
);
/*
* Peer shouldn't send Nak for protocol compression or
* address/control compression requests; they should send
* a Reject instead. If they send a Nak, treat it as a Reject.
*/
NAKCIVOID(CI_PCOMPRESSION, neg_pcompression,
try.neg_pcompression = 0;
);
NAKCIVOID(CI_ACCOMPRESSION, neg_accompression,
try.neg_accompression = 0;
);
/*
* There may be remaining CIs, if the peer is requesting negotiation
* on an option that we didn't include in our request packet.
* If we see an option that we requested, or one we've already seen
* in this packet, then this packet is bad.
* If we wanted to respond by starting to negotiate on the requested
* option(s), we could, but we don't, because except for the
* authentication type and quality protocol, if we are not negotiating
* an option, it is because we were told not to.
* For the authentication type, the Nak from the peer means
* `let me authenticate myself with you' which is a bit pointless.
* For the quality protocol, the Nak means `ask me to send you quality
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