/* $OpenBSD: ipcp.c,v 1.17 2024/08/10 05:32:28 jsg Exp $ */ /* * ipcp.c - PPP IP Control Protocol. * * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The name "Carnegie Mellon University" must not be used to * endorse or promote products derived from this software without * prior written permission. For permission or any legal * details, please contact * Office of Technology Transfer * Carnegie Mellon University * 5000 Forbes Avenue * Pittsburgh, PA 15213-3890 * (412) 268-4387, fax: (412) 268-7395 * tech-transfer@andrew.cmu.edu * * 4. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by Computing Services * at Carnegie Mellon University (http://www.cmu.edu/computing/)." * * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /* * TODO: */ #include #include #include #include #include #include #include #include #include "pppd.h" #include "fsm.h" #include "ipcp.h" #include "pathnames.h" /* global vars */ ipcp_options ipcp_wantoptions[NUM_PPP]; /* Options that we want to request */ ipcp_options ipcp_gotoptions[NUM_PPP]; /* Options that peer ack'd */ ipcp_options ipcp_allowoptions[NUM_PPP]; /* Options we allow peer to request */ ipcp_options ipcp_hisoptions[NUM_PPP]; /* Options that we ack'd */ /* local vars */ static int cis_received[NUM_PPP]; /* # Conf-Reqs received */ static int default_route_set[NUM_PPP]; /* Have set up a default route */ static int proxy_arp_set[NUM_PPP]; /* Have created proxy arp entry */ /* * Callbacks for fsm code. (CI = Configuration Information) */ static void ipcp_resetci(fsm *); /* Reset our CI */ static int ipcp_cilen(fsm *); /* Return length of our CI */ static void ipcp_addci(fsm *, u_char *, int *); /* Add our CI */ static int ipcp_ackci(fsm *, u_char *, int); /* Peer ack'd our CI */ static int ipcp_nakci(fsm *, u_char *, int); /* Peer nak'd our CI */ static int ipcp_rejci(fsm *, u_char *, int); /* Peer rej'd our CI */ static int ipcp_reqci(fsm *, u_char *, int *, int); /* Rcv CI */ static void ipcp_up(fsm *); /* We're UP */ static void ipcp_down(fsm *); /* We're DOWN */ static void ipcp_script(fsm *, char *); /* Run an up/down script */ static void ipcp_finished(fsm *); /* Don't need lower layer */ fsm ipcp_fsm[NUM_PPP]; /* IPCP fsm structure */ static fsm_callbacks ipcp_callbacks = { /* IPCP callback routines */ ipcp_resetci, /* Reset our Configuration Information */ ipcp_cilen, /* Length of our Configuration Information */ ipcp_addci, /* Add our Configuration Information */ ipcp_ackci, /* ACK our Configuration Information */ ipcp_nakci, /* NAK our Configuration Information */ ipcp_rejci, /* Reject our Configuration Information */ ipcp_reqci, /* Request peer's Configuration Information */ ipcp_up, /* Called when fsm reaches OPENED state */ ipcp_down, /* Called when fsm leaves OPENED state */ NULL, /* Called when we want the lower layer up */ ipcp_finished, /* Called when we want the lower layer down */ NULL, /* Called when Protocol-Reject received */ NULL, /* Retransmission is necessary */ NULL, /* Called to handle protocol-specific codes */ "IPCP" /* String name of protocol */ }; /* * Protocol entry points from main code. */ static void ipcp_init(int); static void ipcp_open(int); static void ipcp_close(int, char *); static void ipcp_lowerup(int); static void ipcp_lowerdown(int); static void ipcp_input(int, u_char *, int); static void ipcp_protrej(int); static int ipcp_printpkt(u_char *, int, void (*)(void *, char *, ...), void *); static void ip_check_options(void); static int ip_demand_conf(int); static int ip_active_pkt(u_char *, int); struct protent ipcp_protent = { PPP_IPCP, ipcp_init, ipcp_input, ipcp_protrej, ipcp_lowerup, ipcp_lowerdown, ipcp_open, ipcp_close, ipcp_printpkt, NULL, 1, "IPCP", ip_check_options, ip_demand_conf, ip_active_pkt }; static void ipcp_clear_addrs(int); /* * Lengths of configuration options. */ #define CILEN_VOID 2 #define CILEN_COMPRESS 4 /* min length for compression protocol opt. */ #define CILEN_VJ 6 /* length for RFC1332 Van-Jacobson opt. */ #define CILEN_ADDR 6 /* new-style single address option */ #define CILEN_ADDRS 10 /* old-style dual address option */ #define CODENAME(x) ((x) == CONFACK ? "ACK" : \ (x) == CONFNAK ? "NAK" : "REJ") /* * Make a string representation of a network IP address. */ char * ip_ntoa(u_int32_t ipaddr) { static char b[64]; ipaddr = ntohl(ipaddr); snprintf(b, sizeof b, "%d.%d.%d.%d", (u_char)(ipaddr >> 24), (u_char)(ipaddr >> 16), (u_char)(ipaddr >> 8), (u_char)(ipaddr)); return b; } /* * ipcp_init - Initialize IPCP. */ static void ipcp_init(int unit) { fsm *f = &ipcp_fsm[unit]; ipcp_options *wo = &ipcp_wantoptions[unit]; ipcp_options *ao = &ipcp_allowoptions[unit]; f->unit = unit; f->protocol = PPP_IPCP; f->callbacks = &ipcp_callbacks; fsm_init(&ipcp_fsm[unit]); memset(wo, 0, sizeof(*wo)); memset(ao, 0, sizeof(*ao)); wo->neg_addr = 1; wo->neg_vj = 1; wo->vj_protocol = IPCP_VJ_COMP; wo->maxslotindex = MAX_STATES - 1; /* really max index */ wo->cflag = 1; /* max slots and slot-id compression are currently hardwired in */ /* ppp_if.c to 16 and 1, this needs to be changed (among other */ /* things) gmc */ ao->neg_addr = 1; ao->neg_vj = 1; ao->maxslotindex = MAX_STATES - 1; ao->cflag = 1; /* * XXX These control whether the user may use the proxyarp * and defaultroute options. */ ao->proxy_arp = 1; ao->default_route = 1; } /* * ipcp_open - IPCP is allowed to come up. */ static void ipcp_open(int unit) { fsm_open(&ipcp_fsm[unit]); } /* * ipcp_close - Take IPCP down. */ static void ipcp_close(int unit, char *reason) { fsm_close(&ipcp_fsm[unit], reason); } /* * ipcp_lowerup - The lower layer is up. */ static void ipcp_lowerup(int unit) { fsm_lowerup(&ipcp_fsm[unit]); } /* * ipcp_lowerdown - The lower layer is down. */ static void ipcp_lowerdown(int unit) { fsm_lowerdown(&ipcp_fsm[unit]); } /* * ipcp_input - Input IPCP packet. */ static void ipcp_input(int unit, u_char *p, int len) { fsm_input(&ipcp_fsm[unit], p, len); } /* * ipcp_protrej - A Protocol-Reject was received for IPCP. * * Pretend the lower layer went down, so we shut up. */ static void ipcp_protrej(int unit) { fsm_lowerdown(&ipcp_fsm[unit]); } /* * ipcp_resetci - Reset our CI. */ static void ipcp_resetci(fsm *f) { ipcp_options *wo = &ipcp_wantoptions[f->unit]; wo->req_addr = wo->neg_addr && ipcp_allowoptions[f->unit].neg_addr; if (wo->ouraddr == 0) wo->accept_local = 1; if (wo->hisaddr == 0) wo->accept_remote = 1; ipcp_gotoptions[f->unit] = *wo; cis_received[f->unit] = 0; } /* * ipcp_cilen - Return length of our CI. */ static int ipcp_cilen(fsm *f) { ipcp_options *go = &ipcp_gotoptions[f->unit]; ipcp_options *wo = &ipcp_wantoptions[f->unit]; ipcp_options *ho = &ipcp_hisoptions[f->unit]; #define LENCIVJ(neg, old) (neg ? (old? CILEN_COMPRESS : CILEN_VJ) : 0) #define LENCIADDR(neg, old) (neg ? (old? CILEN_ADDRS : CILEN_ADDR) : 0) /* * First see if we want to change our options to the old * forms because we have received old forms from the peer. */ if (wo->neg_addr && !go->neg_addr && !go->old_addrs) { /* use the old style of address negotiation */ go->neg_addr = 1; go->old_addrs = 1; } if (wo->neg_vj && !go->neg_vj && !go->old_vj) { /* try an older style of VJ negotiation */ if (cis_received[f->unit] == 0) { /* keep trying the new style until we see some CI from the peer */ go->neg_vj = 1; } else { /* use the old style only if the peer did */ if (ho->neg_vj && ho->old_vj) { go->neg_vj = 1; go->old_vj = 1; go->vj_protocol = ho->vj_protocol; } } } return (LENCIADDR(go->neg_addr, go->old_addrs) + LENCIVJ(go->neg_vj, go->old_vj)); } /* * ipcp_addci - Add our desired CIs to a packet. */ static void ipcp_addci(fsm *f, u_char *ucp, int *lenp) { ipcp_options *go = &ipcp_gotoptions[f->unit]; int len = *lenp; #define ADDCIVJ(opt, neg, val, old, maxslotindex, cflag) \ if (neg) { \ int vjlen = old? CILEN_COMPRESS : CILEN_VJ; \ if (len >= vjlen) { \ PUTCHAR(opt, ucp); \ PUTCHAR(vjlen, ucp); \ PUTSHORT(val, ucp); \ if (!old) { \ PUTCHAR(maxslotindex, ucp); \ PUTCHAR(cflag, ucp); \ } \ len -= vjlen; \ } else \ neg = 0; \ } #define ADDCIADDR(opt, neg, old, val1, val2) \ if (neg) { \ int addrlen = (old? CILEN_ADDRS: CILEN_ADDR); \ if (len >= addrlen) { \ u_int32_t l; \ PUTCHAR(opt, ucp); \ PUTCHAR(addrlen, ucp); \ l = ntohl(val1); \ PUTLONG(l, ucp); \ if (old) { \ l = ntohl(val2); \ PUTLONG(l, ucp); \ } \ len -= addrlen; \ } else \ neg = 0; \ } ADDCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), go->neg_addr, go->old_addrs, go->ouraddr, go->hisaddr); ADDCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj, go->maxslotindex, go->cflag); *lenp -= len; } /* * ipcp_ackci - Ack our CIs. * * Returns: * 0 - Ack was bad. * 1 - Ack was good. */ static int ipcp_ackci(fsm *f, u_char *p, int len) { ipcp_options *go = &ipcp_gotoptions[f->unit]; u_short cilen, citype, cishort; u_int32_t cilong; u_char cimaxslotindex, cicflag; /* * 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 ACKCIVJ(opt, neg, val, old, maxslotindex, cflag) \ if (neg) { \ int vjlen = old? CILEN_COMPRESS : CILEN_VJ; \ if ((len -= vjlen) < 0) \ goto bad; \ GETCHAR(citype, p); \ GETCHAR(cilen, p); \ if (cilen != vjlen || \ citype != opt) \ goto bad; \ GETSHORT(cishort, p); \ if (cishort != val) \ goto bad; \ if (!old) { \ GETCHAR(cimaxslotindex, p); \ if (cimaxslotindex != maxslotindex) \ goto bad; \ GETCHAR(cicflag, p); \ if (cicflag != cflag) \ goto bad; \ } \ } #define ACKCIADDR(opt, neg, old, val1, val2) \ if (neg) { \ int addrlen = (old? CILEN_ADDRS: CILEN_ADDR); \ u_int32_t l; \ if ((len -= addrlen) < 0) \ goto bad; \ GETCHAR(citype, p); \ GETCHAR(cilen, p); \ if (cilen != addrlen || \ citype != opt) \ goto bad; \ GETLONG(l, p); \ cilong = htonl(l); \ if (val1 != cilong) \ goto bad; \ if (old) { \ GETLONG(l, p); \ cilong = htonl(l); \ if (val2 != cilong) \ goto bad; \ } \ } ACKCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), go->neg_addr, go->old_addrs, go->ouraddr, go->hisaddr); ACKCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj, go->maxslotindex, go->cflag); /* * If there are any remaining CIs, then this packet is bad. */ if (len != 0) goto bad; return (1); bad: IPCPDEBUG((LOG_INFO, "ipcp_ackci: received bad Ack!")); return (0); } /* * ipcp_nakci - Peer has sent a NAK for some of our CIs. * This should not modify any state if the Nak is bad * or if IPCP is in the OPENED state. * * Returns: * 0 - Nak was bad. * 1 - Nak was good. */ static int ipcp_nakci(fsm *f, u_char *p, int len) { ipcp_options *go = &ipcp_gotoptions[f->unit]; u_char cimaxslotindex, cicflag; u_char citype, cilen, *next; u_short cishort; u_int32_t ciaddr1, ciaddr2, l; ipcp_options no; /* options we've seen Naks for */ ipcp_options try; /* options to request next time */ 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 NAKCIADDR(opt, neg, old, code) \ if (go->neg && \ len >= (cilen = (old? CILEN_ADDRS: CILEN_ADDR)) && \ p[1] == cilen && \ p[0] == opt) { \ len -= cilen; \ INCPTR(2, p); \ GETLONG(l, p); \ ciaddr1 = htonl(l); \ if (old) { \ GETLONG(l, p); \ ciaddr2 = htonl(l); \ no.old_addrs = 1; \ } else \ ciaddr2 = 0; \ no.neg = 1; \ code \ } #define NAKCIVJ(opt, neg, code) \ if (go->neg && \ ((cilen = p[1]) == CILEN_COMPRESS || cilen == CILEN_VJ) && \ len >= cilen && \ p[0] == opt) { \ len -= cilen; \ INCPTR(2, p); \ GETSHORT(cishort, p); \ no.neg = 1; \ code \ } /* * Accept the peer's idea of {our,his} address, if different * from our idea, only if the accept_{local,remote} flag is set. */ NAKCIADDR((go->old_addrs? CI_ADDRS: 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) { GETCHAR(cimaxslotindex, p); GETCHAR(cicflag, p); 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.old_addrs = 0; GETLONG(l, p); ciaddr1 = htonl(l); if (ciaddr1 && go->accept_local) try.ouraddr = ciaddr1; if (try.ouraddr != 0) try.neg_addr = 1; no.neg_addr = 1; break; } 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; bad: IPCPDEBUG((LOG_INFO, "ipcp_nakci: received bad Nak!")); return 0; } /* * ipcp_rejci - Reject some of our CIs. */ static int ipcp_rejci(fsm *f, u_char *p, int len) { ipcp_options *go = &ipcp_gotoptions[f->unit]; u_char cimaxslotindex, ciflag, cilen; u_short cishort; u_int32_t cilong; ipcp_options try; /* options to request next time */ try = *go; /* * Any Rejected 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 REJCIADDR(opt, neg, old, val1, val2) \ if (go->neg && \ len >= (cilen = old? CILEN_ADDRS: CILEN_ADDR) && \ p[1] == cilen && \ p[0] == opt) { \ u_int32_t l; \ len -= cilen; \ INCPTR(2, p); \ GETLONG(l, p); \ cilong = htonl(l); \ /* Check rejected value. */ \ if (cilong != val1) \ goto bad; \ if (old) { \ GETLONG(l, p); \ cilong = htonl(l); \ /* Check rejected value. */ \ if (cilong != val2) \ goto bad; \ } \ try.neg = 0; \ } #define REJCIVJ(opt, neg, val, old, maxslot, cflag) \ if (go->neg && \ p[1] == (old? CILEN_COMPRESS : CILEN_VJ) && \ len >= p[1] && \ p[0] == opt) { \ len -= p[1]; \ INCPTR(2, p); \ GETSHORT(cishort, p); \ /* Check rejected value. */ \ if (cishort != val) \ goto bad; \ if (!old) { \ GETCHAR(cimaxslotindex, p); \ if (cimaxslotindex != maxslot) \ goto bad; \ GETCHAR(ciflag, p); \ if (ciflag != cflag) \ goto bad; \ } \ try.neg = 0; \ } REJCIADDR((go->old_addrs? CI_ADDRS: CI_ADDR), neg_addr, go->old_addrs, go->ouraddr, go->hisaddr); REJCIVJ(CI_COMPRESSTYPE, neg_vj, go->vj_protocol, go->old_vj, go->maxslotindex, go->cflag); /* * If there are any remaining CIs, then this packet is bad. */ if (len != 0) goto bad; /* * Now we can update state. */ if (f->state != OPENED) *go = try; return 1; bad: IPCPDEBUG((LOG_INFO, "ipcp_rejci: received bad Reject!")); return 0; } /* * ipcp_reqci - Check the peer's requested CIs and send appropriate response. * * Returns: CONFACK, CONFNAK or CONFREJ and input packet modified * appropriately. If reject_if_disagree is non-zero, doesn't return * CONFNAK; returns CONFREJ if it can't return CONFACK. */ static int ipcp_reqci(fsm *f, u_char *inp, int *len, int reject_if_disagree) { ipcp_options *wo = &ipcp_wantoptions[f->unit]; ipcp_options *ho = &ipcp_hisoptions[f->unit]; ipcp_options *ao = &ipcp_allowoptions[f->unit]; ipcp_options *go = &ipcp_gotoptions[f->unit]; u_char *cip, *next; /* Pointer to current and next CIs */ u_short cilen, citype; /* Parsed len, type */ u_short cishort; /* Parsed short value */ u_int32_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 */ u_char maxslotindex, cflag; int d; cis_received[f->unit] = 1; /* * Reset all his options. */ BZERO(ho, sizeof(*ho)); /* * Process all his options. */ next = inp; while (l) { orc = CONFACK; /* Assume success */ cip = p = next; /* Remember beginning 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((LOG_INFO, "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: IPCPDEBUG((LOG_INFO, "ipcp: received ADDRS ")); if (!ao->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 = htonl(tl); IPCPDEBUG((LOG_INFO, "(%s:", ip_ntoa(ciaddr1))); if (ciaddr1 != wo->hisaddr && (ciaddr1 == 0 || !wo->accept_remote)) { orc = CONFNAK; if (!reject_if_disagree) { DECPTR(sizeof(u_int32_t), p); tl = 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 destination address (ours) */ ciaddr2 = htonl(tl); IPCPDEBUG((LOG_INFO, "%s)", ip_ntoa(ciaddr2))); if (ciaddr2 != wo->ouraddr) { if (ciaddr2 == 0 || !wo->accept_local) { orc = CONFNAK; if (!reject_if_disagree) { DECPTR(sizeof(u_int32_t), p); tl = ntohl(wo->ouraddr); PUTLONG(tl, p); } } else { go->ouraddr = ciaddr2; /* accept peer's idea */ } } ho->neg_addr = 1; ho->old_addrs = 1; ho->hisaddr = ciaddr1; ho->ouraddr = ciaddr2; break; case CI_ADDR: IPCPDEBUG((LOG_INFO, "ipcp: received ADDR ")); if (!ao->neg_addr || 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 = htonl(tl); IPCPDEBUG((LOG_INFO, "(%s)", ip_ntoa(ciaddr1))); if (ciaddr1 != wo->hisaddr && (ciaddr1 == 0 || !wo->accept_remote)) { orc = CONFNAK; if (!reject_if_disagree) { DECPTR(sizeof(u_int32_t), p); tl = 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; case CI_MS_DNS1: case CI_MS_DNS2: /* Microsoft primary or secondary DNS request */ d = citype == CI_MS_DNS2; IPCPDEBUG((LOG_INFO, "ipcp: received DNS%d Request ", d+1)); /* 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 (htonl(tl) != ao->dnsaddr[d]) { DECPTR(sizeof(u_int32_t), p); tl = ntohl(ao->dnsaddr[d]); PUTLONG(tl, p); orc = CONFNAK; } break; case CI_MS_WINS1: case CI_MS_WINS2: /* Microsoft primary or secondary WINS request */ d = citype == CI_MS_WINS2; IPCPDEBUG((LOG_INFO, "ipcp: received WINS%d Request ", d+1)); /* 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 (htonl(tl) != ao->winsaddr[d]) { DECPTR(sizeof(u_int32_t), p); tl = ntohl(ao->winsaddr[d]); PUTLONG(tl, p); orc = CONFNAK; } break; case CI_COMPRESSTYPE: IPCPDEBUG((LOG_INFO, "ipcp: received COMPRESSTYPE ")); if (!ao->neg_vj || (cilen != CILEN_VJ && cilen != CILEN_COMPRESS)) { orc = CONFREJ; break; } GETSHORT(cishort, p); IPCPDEBUG((LOG_INFO, "(%d)", cishort)); 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; default: orc = CONFREJ; break; } endswitch: IPCPDEBUG((LOG_INFO, " (%s)\n", CODENAME(orc))); 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) BCOPY(cip, ucp, 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 && wo->req_addr && !reject_if_disagree) { 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 = ntohl(wo->hisaddr); PUTLONG(tl, ucp); } *len = ucp - inp; /* Compute output length */ IPCPDEBUG((LOG_INFO, "ipcp: returning Configure-%s", CODENAME(rc))); return (rc); /* Return final code */ } /* * ip_check_options - check that any IP-related options are OK, * and assign appropriate defaults. */ static void ip_check_options(void) { struct hostent *hp; u_int32_t local; ipcp_options *wo = &ipcp_wantoptions[0]; /* * Default our local IP address based on our hostname. * If local IP address already given, don't bother. */ if (wo->ouraddr == 0 && !disable_defaultip) { /* * Look up our hostname (possibly with domain name appended) * and take the first IP address as our local IP address. * If there isn't an IP address for our hostname, too bad. */ wo->accept_local = 1; /* don't insist on this default value */ if ((hp = gethostbyname(hostname)) != NULL) { local = *(u_int32_t *)hp->h_addr; if (local != 0 && !bad_ip_adrs(local)) wo->ouraddr = local; } } if (demand && wo->hisaddr == 0) { option_error("remote IP address required for demand-dialling\n"); exit(1); } #if 0 if (demand && wo->accept_remote) { option_error("ipcp-accept-remote is incompatible with demand\n"); exit(1); } #endif } /* * ip_demand_conf - configure the interface as though * IPCP were up, for use with dial-on-demand. */ static int ip_demand_conf(int u) { ipcp_options *wo = &ipcp_wantoptions[u]; if (!sifaddr(u, wo->ouraddr, wo->hisaddr, GetMask(wo->ouraddr))) return 0; 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; syslog(LOG_NOTICE, "local IP address %s", ip_ntoa(wo->ouraddr)); syslog(LOG_NOTICE, "remote IP address %s", ip_ntoa(wo->hisaddr)); return 1; } /* * ipcp_up - IPCP has come UP. * * Configure the IP network interface appropriately and bring it up. */ static void ipcp_up(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]; np_up(f->unit, PPP_IP); IPCPDEBUG((LOG_INFO, "ipcp: up")); /* * We must have a non-zero IP address for both ends of the link. */ if (!ho->neg_addr) ho->hisaddr = wo->hisaddr; if (ho->hisaddr == 0) { syslog(LOG_ERR, "Could not determine remote IP address"); ipcp_close(f->unit, "Could not determine remote IP address"); return; } if (go->ouraddr == 0) { syslog(LOG_ERR, "Could not determine local IP address"); ipcp_close(f->unit, "Could not determine local IP address"); return; } script_setenv("IPLOCAL", ip_ntoa(go->ouraddr)); script_setenv("IPREMOTE", ip_ntoa(ho->hisaddr)); /* * Check that the peer is allowed to use the IP address it wants. */ if (!auth_ip_addr(f->unit, ho->hisaddr)) { syslog(LOG_ERR, "Peer is not authorized to use remote address %s", ip_ntoa(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) { if (go->ouraddr != wo->ouraddr) syslog(LOG_WARNING, "Local IP address changed to %s", ip_ntoa(go->ouraddr)); if (ho->hisaddr != wo->hisaddr) syslog(LOG_WARNING, "Remote IP address changed to %s", ip_ntoa(ho->hisaddr)); ipcp_clear_addrs(f->unit); /* Set the interface to the new addresses */ mask = GetMask(go->ouraddr); if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) { IPCPDEBUG((LOG_WARNING, "sifaddr 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)) { IPCPDEBUG((LOG_WARNING, "sifaddr failed")); ipcp_close(f->unit, "Interface configuration failed"); return; } #endif /* bring the interface up for IP */ if (!sifup(f->unit)) { IPCPDEBUG((LOG_WARNING, "sifup failed")); ipcp_close(f->unit, "Interface configuration failed"); return; } #if (defined(SVR4) && (defined(SNI) || defined(__USLC__))) if (!sifaddr(f->unit, go->ouraddr, ho->hisaddr, mask)) { IPCPDEBUG((LOG_WARNING, "sifaddr 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; syslog(LOG_NOTICE, "local IP address %s", ip_ntoa(go->ouraddr)); syslog(LOG_NOTICE, "remote IP address %s", ip_ntoa(ho->hisaddr)); } /* * Execute the ip-up script, like this: * /etc/ppp/ip-up interface tty speed local-IP remote-IP */ ipcp_script(f, _PATH_IPUP); } /* * ipcp_down - IPCP has gone DOWN. * * Take the IP network interface down, clear its addresses * and delete routes through it. */ static void ipcp_down(fsm *f) { IPCPDEBUG((LOG_INFO, "ipcp: down")); np_down(f->unit, PPP_IP); sifvjcomp(f->unit, 0, 0, 0); /* * 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 { sifdown(f->unit); ipcp_clear_addrs(f->unit); } /* Execute the ip-down script */ ipcp_script(f, _PATH_IPDOWN); } /* * ipcp_clear_addrs() - clear the interface addresses, routes, * proxy arp entries, etc. */ static void ipcp_clear_addrs(int unit) { u_int32_t ouraddr, hisaddr; ouraddr = ipcp_gotoptions[unit].ouraddr; hisaddr = ipcp_hisoptions[unit].hisaddr; 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(fsm *f) { np_finished(f->unit, PPP_IP); } /* * ipcp_script - Execute a script with arguments * interface-name tty-name speed local-IP remote-IP. */ static void ipcp_script(fsm *f, char *script) { char strspeed[32], strlocal[32], strremote[32]; char *argv[8]; snprintf(strspeed, sizeof strspeed, "%d", baud_rate); strlcpy(strlocal, ip_ntoa(ipcp_gotoptions[f->unit].ouraddr), sizeof strlocal); strlcpy(strremote, ip_ntoa(ipcp_hisoptions[f->unit].hisaddr), sizeof strremote); argv[0] = script; argv[1] = ifname; argv[2] = devnam; argv[3] = strspeed; argv[4] = strlocal; argv[5] = strremote; argv[6] = ipparam; argv[7] = NULL; run_program(script, argv, 0); } /* * ipcp_printpkt - print the contents of an IPCP packet. */ static char *ipcp_codenames[] = { "ConfReq", "ConfAck", "ConfNak", "ConfRej", "TermReq", "TermAck", "CodeRej" }; static int ipcp_printpkt(u_char *p, int plen, void (*printer)(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 %I", 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(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 #define IPPROTO_TCP 6 #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(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; }