in net/ip/lwip_base/src/netif/ppp/ipcp.c [1506:1795]
static int ipcp_reqci(fsm *f, u_char *inp, int *len, int reject_if_disagree) {
ppp_pcb *pcb = f->pcb;
ipcp_options *wo = &pcb->ipcp_wantoptions;
ipcp_options *ho = &pcb->ipcp_hisoptions;
ipcp_options *ao = &pcb->ipcp_allowoptions;
u_char *cip, *next; /* Pointer to current and next CIs */
u_short cilen, citype; /* Parsed len, type */
#if VJ_SUPPORT
u_short cishort; /* Parsed short value */
#endif /* VJ_SUPPORT */
u32_t tl, ciaddr1, ciaddr2;/* Parsed address values */
int rc = CONFACK; /* Final packet return code */
int orc; /* Individual option return code */
u_char *p; /* Pointer to next char to parse */
u_char *ucp = inp; /* Pointer to current output char */
int l = *len; /* Length left */
#if VJ_SUPPORT
u_char maxslotindex, cflag;
#endif /* VJ_SUPPORT */
#if LWIP_DNS
int d;
#endif /* LWIP_DNS */
/*
* Reset all his options.
*/
BZERO(ho, sizeof(*ho));
/*
* Process all his options.
*/
next = inp;
while (l) {
orc = CONFACK; /* Assume success */
cip = p = next; /* Remember begining of CI */
if (l < 2 || /* Not enough data for CI header or */
p[1] < 2 || /* CI length too small or */
p[1] > l) { /* CI length too big? */
IPCPDEBUG(("ipcp_reqci: bad CI length!"));
orc = CONFREJ; /* Reject bad CI */
cilen = l; /* Reject till end of packet */
l = 0; /* Don't loop again */
goto endswitch;
}
GETCHAR(citype, p); /* Parse CI type */
GETCHAR(cilen, p); /* Parse CI length */
l -= cilen; /* Adjust remaining length */
next += cilen; /* Step to next CI */
switch (citype) { /* Check CI type */
case CI_ADDRS:
if (!ao->old_addrs || ho->neg_addr ||
cilen != CILEN_ADDRS) { /* Check CI length */
orc = CONFREJ; /* Reject CI */
break;
}
/*
* If he has no address, or if we both have his address but
* disagree about it, then NAK it with our idea.
* In particular, if we don't know his address, but he does,
* then accept it.
*/
GETLONG(tl, p); /* Parse source address (his) */
ciaddr1 = lwip_htonl(tl);
if (ciaddr1 != wo->hisaddr
&& (ciaddr1 == 0 || !wo->accept_remote)) {
orc = CONFNAK;
if (!reject_if_disagree) {
DECPTR(sizeof(u32_t), p);
tl = lwip_ntohl(wo->hisaddr);
PUTLONG(tl, p);
}
} else if (ciaddr1 == 0 && wo->hisaddr == 0) {
/*
* If neither we nor he knows his address, reject the option.
*/
orc = CONFREJ;
wo->req_addr = 0; /* don't NAK with 0.0.0.0 later */
break;
}
/*
* If he doesn't know our address, or if we both have our address
* but disagree about it, then NAK it with our idea.
*/
GETLONG(tl, p); /* Parse desination address (ours) */
ciaddr2 = lwip_htonl(tl);
if (ciaddr2 != wo->ouraddr) {
if (ciaddr2 == 0 || !wo->accept_local) {
orc = CONFNAK;
if (!reject_if_disagree) {
DECPTR(sizeof(u32_t), p);
tl = lwip_ntohl(wo->ouraddr);
PUTLONG(tl, p);
}
} else {
wo->ouraddr = ciaddr2; /* accept peer's idea */
}
}
ho->old_addrs = 1;
ho->hisaddr = ciaddr1;
ho->ouraddr = ciaddr2;
break;
case CI_ADDR:
if (!ao->neg_addr || ho->old_addrs ||
cilen != CILEN_ADDR) { /* Check CI length */
orc = CONFREJ; /* Reject CI */
break;
}
/*
* If he has no address, or if we both have his address but
* disagree about it, then NAK it with our idea.
* In particular, if we don't know his address, but he does,
* then accept it.
*/
GETLONG(tl, p); /* Parse source address (his) */
ciaddr1 = lwip_htonl(tl);
if (ciaddr1 != wo->hisaddr
&& (ciaddr1 == 0 || !wo->accept_remote)) {
orc = CONFNAK;
if (!reject_if_disagree) {
DECPTR(sizeof(u32_t), p);
tl = lwip_ntohl(wo->hisaddr);
PUTLONG(tl, p);
}
} else if (ciaddr1 == 0 && wo->hisaddr == 0) {
/*
* Don't ACK an address of 0.0.0.0 - reject it instead.
*/
orc = CONFREJ;
wo->req_addr = 0; /* don't NAK with 0.0.0.0 later */
break;
}
ho->neg_addr = 1;
ho->hisaddr = ciaddr1;
break;
#if LWIP_DNS
case CI_MS_DNS1:
case CI_MS_DNS2:
/* Microsoft primary or secondary DNS request */
d = citype == CI_MS_DNS2;
/* If we do not have a DNS address then we cannot send it */
if (ao->dnsaddr[d] == 0 ||
cilen != CILEN_ADDR) { /* Check CI length */
orc = CONFREJ; /* Reject CI */
break;
}
GETLONG(tl, p);
if (lwip_htonl(tl) != ao->dnsaddr[d]) {
DECPTR(sizeof(u32_t), p);
tl = lwip_ntohl(ao->dnsaddr[d]);
PUTLONG(tl, p);
orc = CONFNAK;
}
break;
#endif /* LWIP_DNS */
#if 0 /* UNUSED - WINS */
case CI_MS_WINS1:
case CI_MS_WINS2:
/* Microsoft primary or secondary WINS request */
d = citype == CI_MS_WINS2;
/* If we do not have a DNS address then we cannot send it */
if (ao->winsaddr[d] == 0 ||
cilen != CILEN_ADDR) { /* Check CI length */
orc = CONFREJ; /* Reject CI */
break;
}
GETLONG(tl, p);
if (lwip_htonl(tl) != ao->winsaddr[d]) {
DECPTR(sizeof(u32_t), p);
tl = lwip_ntohl(ao->winsaddr[d]);
PUTLONG(tl, p);
orc = CONFNAK;
}
break;
#endif /* UNUSED - WINS */
#if VJ_SUPPORT
case CI_COMPRESSTYPE:
if (!ao->neg_vj ||
(cilen != CILEN_VJ && cilen != CILEN_COMPRESS)) {
orc = CONFREJ;
break;
}
GETSHORT(cishort, p);
if (!(cishort == IPCP_VJ_COMP ||
(cishort == IPCP_VJ_COMP_OLD && cilen == CILEN_COMPRESS))) {
orc = CONFREJ;
break;
}
ho->neg_vj = 1;
ho->vj_protocol = cishort;
if (cilen == CILEN_VJ) {
GETCHAR(maxslotindex, p);
if (maxslotindex > ao->maxslotindex) {
orc = CONFNAK;
if (!reject_if_disagree){
DECPTR(1, p);
PUTCHAR(ao->maxslotindex, p);
}
}
GETCHAR(cflag, p);
if (cflag && !ao->cflag) {
orc = CONFNAK;
if (!reject_if_disagree){
DECPTR(1, p);
PUTCHAR(wo->cflag, p);
}
}
ho->maxslotindex = maxslotindex;
ho->cflag = cflag;
} else {
ho->old_vj = 1;
ho->maxslotindex = MAX_STATES - 1;
ho->cflag = 1;
}
break;
#endif /* VJ_SUPPORT */
default:
orc = CONFREJ;
break;
}
endswitch:
if (orc == CONFACK && /* Good CI */
rc != CONFACK) /* but prior CI wasnt? */
continue; /* Don't send this one */
if (orc == CONFNAK) { /* Nak this CI? */
if (reject_if_disagree) /* Getting fed up with sending NAKs? */
orc = CONFREJ; /* Get tough if so */
else {
if (rc == CONFREJ) /* Rejecting prior CI? */
continue; /* Don't send this one */
if (rc == CONFACK) { /* Ack'd all prior CIs? */
rc = CONFNAK; /* Not anymore... */
ucp = inp; /* Backup */
}
}
}
if (orc == CONFREJ && /* Reject this CI */
rc != CONFREJ) { /* but no prior ones? */
rc = CONFREJ;
ucp = inp; /* Backup */
}
/* Need to move CI? */
if (ucp != cip)
MEMCPY(ucp, cip, cilen); /* Move it */
/* Update output pointer */
INCPTR(cilen, ucp);
}
/*
* If we aren't rejecting this packet, and we want to negotiate
* their address, and they didn't send their address, then we
* send a NAK with a CI_ADDR option appended. We assume the
* input buffer is long enough that we can append the extra
* option safely.
*/
if (rc != CONFREJ && !ho->neg_addr && !ho->old_addrs &&
wo->req_addr && !reject_if_disagree && !pcb->settings.noremoteip) {
if (rc == CONFACK) {
rc = CONFNAK;
ucp = inp; /* reset pointer */
wo->req_addr = 0; /* don't ask again */
}
PUTCHAR(CI_ADDR, ucp);
PUTCHAR(CILEN_ADDR, ucp);
tl = lwip_ntohl(wo->hisaddr);
PUTLONG(tl, ucp);
}
*len = ucp - inp; /* Compute output length */
IPCPDEBUG(("ipcp: returning Configure-%s", CODENAME(rc)));
return (rc); /* Return final code */
}