+ NAKCIADDR(CI_ADDR, neg_addr, go->old_addrs,
+ if (go->accept_local && ciaddr1) { /* Do we know our address? */
+ try.ouraddr = ciaddr1;
+ IPCPDEBUG((LOG_INFO, "local IP address %s",
+ ip_ntoa(ciaddr1)));
+ }
+ if (go->accept_remote && ciaddr2) { /* Does he know his? */
+ try.hisaddr = ciaddr2;
+ IPCPDEBUG((LOG_INFO, "remote IP address %s",
+ ip_ntoa(ciaddr2)));
+ }
+ );
+
+ /*
+ * Accept the peer's value of maxslotindex provided that it
+ * is less than what we asked for. Turn off slot-ID compression
+ * if the peer wants. Send old-style compress-type option if
+ * the peer wants.
+ */
+ NAKCIVJ(CI_COMPRESSTYPE, neg_vj,
+ if (cilen == CILEN_VJ) {
+ if (cishort == IPCP_VJ_COMP) {
+ try.old_vj = 0;
+ if (cimaxslotindex < go->maxslotindex)
+ try.maxslotindex = cimaxslotindex;
+ if (!cicflag)
+ try.cflag = 0;
+ } else {
+ try.neg_vj = 0;
+ }
+ } else {
+ if (cishort == IPCP_VJ_COMP || cishort == IPCP_VJ_COMP_OLD) {
+ try.old_vj = 1;
+ try.vj_protocol = cishort;
+ } else {
+ try.neg_vj = 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 they want to negotiate about IP addresses, we comply.
+ * If they want us to ask for compression, we refuse.
+ */
+ while (len > CILEN_VOID) {
+ GETCHAR(citype, p);
+ GETCHAR(cilen, p);
+ if( (len -= cilen) < 0 )
+ goto bad;
+ next = p + cilen - 2;
+
+ switch (citype) {
+ case CI_COMPRESSTYPE:
+ if (go->neg_vj || no.neg_vj ||
+ (cilen != CILEN_VJ && cilen != CILEN_COMPRESS))
+ goto bad;
+ no.neg_vj = 1;
+ break;
+ case CI_ADDRS:
+ if (go->neg_addr && go->old_addrs || no.old_addrs
+ || cilen != CILEN_ADDRS)
+ goto bad;
+ try.neg_addr = 1;
+ try.old_addrs = 1;
+ GETLONG(l, p);
+ ciaddr1 = htonl(l);
+ if (ciaddr1 && go->accept_local)
+ try.ouraddr = ciaddr1;
+ GETLONG(l, p);
+ ciaddr2 = htonl(l);
+ if (ciaddr2 && go->accept_remote)
+ try.hisaddr = ciaddr2;
+ no.old_addrs = 1;
+ break;
+ case CI_ADDR:
+ if (go->neg_addr || no.neg_addr || cilen != CILEN_ADDR)
+ goto bad;
+ try.neg_addr = 1;
+ try.old_addrs = 0;
+ GETLONG(l, p);
+ ciaddr1 = htonl(l);
+ if (ciaddr1 && go->accept_local)
+ try.ouraddr = ciaddr1;
+ no.neg_addr = 1;
+ break;
+ default:
+ goto bad;
+ }
+ p = next;
+ }
+
+ /* If there is still anything left, this packet is bad. */
+ if (len != 0)
+ goto bad;
+
+ /*
+ * OK, the Nak is good. Now we can update state.
+ */
+ if (f->state != OPENED)
+ *go = try;
+
+ return 1;
+