+/*
+ * ccp.c - PPP Compression Control Protocol.
+ */
+
+#ifndef lint
+static char rcsid[] = "$Id: ccp.c,v 1.1 1994/08/11 01:44:32 paulus Exp $";
+#endif
+
+#include <syslog.h>
+#include <sys/ioctl.h>
+
+#include "pppd.h"
+#include "ppp.h"
+#include "fsm.h"
+#include "ccp.h"
+
+fsm ccp_fsm[NPPP];
+ccp_options ccp_wantoptions[NPPP]; /* what to request the peer to use */
+ccp_options ccp_gotoptions[NPPP]; /* what the peer agreed to do */
+ccp_options ccp_allowoptions[NPPP]; /* what we'll agree to do */
+ccp_options ccp_hisoptions[NPPP]; /* what we agreed to do */
+
+/*
+ * Callbacks for fsm code.
+ */
+static void ccp_resetci __ARGS((fsm *));
+static int ccp_cilen __ARGS((fsm *));
+static void ccp_addci __ARGS((fsm *, u_char *, int *));
+static int ccp_ackci __ARGS((fsm *, u_char *, int));
+static int ccp_nakci __ARGS((fsm *, u_char *, int));
+static int ccp_rejci __ARGS((fsm *, u_char *, int));
+static int ccp_reqci __ARGS((fsm *, u_char *, int *, int));
+static void ccp_up __ARGS((fsm *));
+static void ccp_down __ARGS((fsm *));
+static int ccp_extcode __ARGS((fsm *, int, int, u_char *, int));
+static void ccp_rack_timeout __ARGS(());
+
+static fsm_callbacks ccp_callbacks = {
+ ccp_resetci,
+ ccp_cilen,
+ ccp_addci,
+ ccp_ackci,
+ ccp_nakci,
+ ccp_rejci,
+ ccp_reqci,
+ ccp_up,
+ ccp_down,
+ NULL,
+ NULL,
+ NULL,
+ NULL,
+ ccp_extcode,
+ "CCP"
+};
+
+/*
+ * Length of configuration options, which describe possible
+ * compression methods.
+ */
+#define CILEN_BSD 3
+
+/*
+ * Configuration option values for compression methods.
+ */
+#define CI_BSD_COMPRESS 0x21
+
+/*
+ * Local state (mainly for handling reset-reqs and reset-acks
+ */
+static int ccp_localstate[NPPP];
+#define RACK_PENDING 1 /* waiting for reset-ack */
+#define RREQ_REPEAT 2 /* send another reset-req if no reset-ack */
+
+#define RACKTIMEOUT 1 /* second */
+
+/*
+ * ccp_init - initialize CCP.
+ */
+void
+ccp_init(unit)
+ int unit;
+{
+ fsm *f = &ccp_fsm[unit];
+
+ f->unit = unit;
+ f->protocol = CCP;
+ f->callbacks = &ccp_callbacks;
+ fsm_init(f);
+
+ memset(&ccp_wantoptions[unit], 0, sizeof(ccp_options));
+ memset(&ccp_gotoptions[unit], 0, sizeof(ccp_options));
+ memset(&ccp_allowoptions[unit], 0, sizeof(ccp_options));
+ memset(&ccp_hisoptions[unit], 0, sizeof(ccp_options));
+
+ ccp_wantoptions[0].bsd_bits = 12; /* default value */
+
+ ccp_allowoptions[0].bsd_compress = 1;
+ ccp_allowoptions[0].bsd_bits = MAX_BSD_BITS;
+}
+
+/*
+ * ccp_open - CCP is allowed to come up.
+ */
+void
+ccp_open(unit)
+ int unit;
+{
+ fsm *f = &ccp_fsm[unit];
+
+ if (f->state != OPENED)
+ ccp_flags_set(unit, 1, 0);
+ fsm_open(f);
+}
+
+/*
+ * ccp_close - Terminate CCP.
+ */
+void
+ccp_close(unit)
+ int unit;
+{
+ ccp_flags_set(unit, 0, 0);
+ fsm_close(&ccp_fsm[unit]);
+}
+
+/*
+ * ccp_lowerup - we may now transmit CCP packets.
+ */
+void
+ccp_lowerup(unit)
+ int unit;
+{
+ fsm_lowerup(&ccp_fsm[unit]);
+}
+
+/*
+ * ccp_lowerdown - we may not transmit CCP packets.
+ */
+void
+ccp_lowerdown(unit)
+ int unit;
+{
+ fsm_lowerdown(&ccp_fsm[unit]);
+}
+
+/*
+ * ccp_input - process a received CCP packet.
+ */
+void
+ccp_input(unit, p, len)
+ int unit;
+ u_char *p;
+ int len;
+{
+ fsm_input(&ccp_fsm[unit], p, len);
+}
+
+/*
+ * Handle a CCP-specific code.
+ */
+static int
+ccp_extcode(f, code, id, p, len)
+ fsm *f;
+ int code, id;
+ u_char *p;
+ int len;
+{
+ switch (code) {
+ case RESETREQ:
+ if (f->state != OPENED)
+ break;
+ /* send a reset-ack, which the transmitter will see and
+ reset its compression state. */
+ fsm_sdata(f, RESETACK, id, NULL, 0);
+ break;
+
+ case RESETACK:
+ if (ccp_localstate[f->unit] & RACK_PENDING && id == f->reqid) {
+ ccp_localstate[f->unit] &= ~(RACK_PENDING | RREQ_REPEAT);
+ UNTIMEOUT(ccp_rack_timeout, (caddr_t) f);
+ }
+ break;
+
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * ccp_protrej - peer doesn't talk CCP.
+ */
+void
+ccp_protrej(unit)
+ int unit;
+{
+ ccp_flags_set(unit, 0, 0);
+ fsm_lowerdown(&ccp_fsm[unit]);
+}
+
+/*
+ * ccp_resetci - initialize at start of negotiation.
+ */
+static void
+ccp_resetci(f)
+ fsm *f;
+{
+ ccp_gotoptions[f->unit] = ccp_wantoptions[f->unit];
+}
+
+/*
+ * ccp_cilen - Return total length of our configuration info.
+ */
+static int
+ccp_cilen(f)
+ fsm *f;
+{
+ ccp_options *go = &ccp_gotoptions[f->unit];
+
+ return (go->bsd_compress? CILEN_BSD: 0);
+}
+
+/*
+ * ccp_addci - put our requests in a packet.
+ */
+static void
+ccp_addci(f, p, lenp)
+ fsm *f;
+ u_char *p;
+ int *lenp;
+{
+ ccp_options *go = &ccp_gotoptions[f->unit];
+ u_char *p0 = p;
+
+ if (go->bsd_compress) {
+ p[0] = CI_BSD_COMPRESS;
+ p[1] = CILEN_BSD;
+ p[2] = go->bsd_bits;
+ p += 3;
+ }
+ *lenp = p - p0;
+}
+
+/*
+ * ccp_ackci - process a received configure-ack, and return
+ * 1 iff the packet was OK.
+ */
+static int
+ccp_ackci(f, p, len)
+ fsm *f;
+ u_char *p;
+ int len;
+{
+ ccp_options *go = &ccp_gotoptions[f->unit];
+
+ if (go->bsd_compress) {
+ if (len != 3 || p[0] != CI_BSD_COMPRESS
+ || p[1] != CILEN_BSD || p[2] != go->bsd_bits)
+ return 0;
+ p += 3;
+ len -= 3;
+ }
+ if (len != 0)
+ return 0;
+ return 1;
+}
+
+/*
+ * ccp_nakci - process received configure-nak.
+ * Returns 1 iff the nak was OK.
+ */
+static int
+ccp_nakci(f, p, len)
+ fsm *f;
+ u_char *p;
+ int len;
+{
+ ccp_options *go = &ccp_gotoptions[f->unit];
+ ccp_options no; /* options we've seen already */
+ ccp_options try; /* options to ask for next time */
+
+ memset(&no, 0, sizeof(no));
+ try = *go;
+
+ if (go->bsd_compress && len >= CILEN_BSD && p[0] == CI_BSD_COMPRESS
+ && p[1] == CILEN_BSD) {
+ no.bsd_compress = 1;
+ /*
+ * Peer wants us to use a different number of bits.
+ */
+ if (p[2] < go->bsd_bits)
+ try.bsd_bits = p[2];
+ p += CILEN_BSD;
+ len -= CILEN_BSD;
+ }
+
+ /*
+ * Have a look at any remaining options...???
+ */
+
+ if (len != 0)
+ return 0;
+
+ if (f->state != OPENED)
+ *go = try;
+ return 1;
+}
+
+/*
+ * ccp_rejci - reject some of our suggested compression methods.
+ */
+static int
+ccp_rejci(f, p, len)
+ fsm *f;
+ u_char *p;
+ int len;
+{
+ ccp_options *go = &ccp_gotoptions[f->unit];
+ ccp_options try; /* options to request next time */
+
+ try = *go;
+
+ if (go->bsd_compress && len >= CILEN_BSD && p[0] == CI_BSD_COMPRESS
+ && p[1] == CILEN_BSD) {
+ if (p[2] != go->bsd_bits)
+ return 0;
+ try.bsd_compress = 0;
+ p += CILEN_BSD;
+ len -= CILEN_BSD;
+ }
+
+ if (len != 0)
+ return 0;
+
+ if (f->state != OPENED)
+ *go = try;
+
+ return 1;
+}
+
+/*
+ * ccp_reqci - processed a received configure-request.
+ * Returns CONFACK, CONFNAK or CONFREJ and the packet modified
+ * appropriately.
+ */
+static int
+ccp_reqci(f, p, lenp, dont_nak)
+ fsm *f;
+ u_char *p;
+ int *lenp;
+ int dont_nak;
+{
+ int ret, newret;
+ u_char *p0, *retp;
+ int len, clen, type;
+ ccp_options *ho = &ccp_hisoptions[f->unit];
+ ccp_options *ao = &ccp_allowoptions[f->unit];
+
+ ret = CONFACK;
+ p0 = p;
+ len = *lenp;
+
+ memset(ho, 0, sizeof(ccp_options));
+
+ while (len > 0) {
+ newret = CONFACK;
+ if (len < 2 || p[1] < 2 || p[1] > len) {
+ /* length is bad */
+ clen = len;
+ newret = CONFREJ;
+
+ } else {
+ type = p[0];
+ clen = p[1];
+
+ switch (type) {
+ case CI_BSD_COMPRESS:
+ if (!ao->bsd_compress || clen != CILEN_BSD) {
+ newret = CONFREJ;
+ break;
+ }
+
+ ho->bsd_compress = 1;
+ ho->bsd_bits = p[2];
+ if (ho->bsd_bits < MIN_BSD_BITS
+ || ho->bsd_bits > ao->bsd_bits) {
+ newret = CONFNAK;
+ if (!dont_nak)
+ p[2] = (ho->bsd_bits < MIN_BSD_BITS? MIN_BSD_BITS:
+ ao->bsd_bits);
+ }
+
+ break;
+
+ default:
+ newret = CONFREJ;
+ }
+ }
+
+ if (!(newret == CONFACK || newret == CONFNAK && ret == CONFREJ)) {
+ /* we're returning this option */
+ if (newret != ret) {
+ retp = p0;
+ ret = newret;
+ }
+ if (p != retp)
+ BCOPY(p, retp, clen);
+ retp += clen;
+ }
+
+ p += clen;
+ len -= clen;
+ }
+
+ if (ret != CONFACK)
+ *lenp = retp - p0;
+ return ret;
+}
+
+/*
+ * CCP has come up - inform the kernel driver.
+ */
+static void
+ccp_up(f)
+ fsm *f;
+{
+ ccp_flags_set(f->unit, 1, 1);
+}
+
+/*
+ * CCP has gone down - inform the kernel driver.
+ */
+static void
+ccp_down(f)
+ fsm *f;
+{
+ if (ccp_localstate[f->unit] & RACK_PENDING)
+ UNTIMEOUT(ccp_rack_timeout, (caddr_t) f);
+ ccp_localstate[f->unit] = 0;
+ ccp_flags_set(f->unit, 1, 0);
+}
+
+/*
+ * Print the contents of a CCP packet.
+ */
+char *ccp_codenames[] = {
+ "ConfReq", "ConfAck", "ConfNak", "ConfRej",
+ "TermReq", "TermAck", "CodeRej",
+ NULL, NULL, NULL, NULL, NULL, NULL,
+ "ResetReq", "ResetAck",
+};
+
+int
+ccp_printpkt(p, plen, printer, arg)
+ u_char *p;
+ int plen;
+ void (*printer) __ARGS((void *, char *, ...));
+ void *arg;
+{
+ u_char *p0, *optend;
+ int code, id, len;
+ int optlen;
+
+ p0 = p;
+ if (plen < HEADERLEN)
+ return 0;
+ code = p[0];
+ id = p[1];
+ len = (p[2] << 8) + p[3];
+ if (len < HEADERLEN || len > plen)
+ return 0;
+
+ if (code >= 1 && code <= sizeof(ccp_codenames) / sizeof(char *)
+ && ccp_codenames[code-1] != NULL)
+ printer(arg, " %s", ccp_codenames[code-1]);
+ else
+ printer(arg, " code=0x%x", code);
+ printer(arg, " id=0x%x", id);
+ len -= HEADERLEN;
+ p += HEADERLEN;
+
+ switch (code) {
+ case CONFREQ:
+ case CONFACK:
+ case CONFNAK:
+ case CONFREJ:
+ /* print list of possible compression methods */
+ while (len >= 2) {
+ code = p[0];
+ optlen = p[1];
+ if (optlen < 2 || optlen > len)
+ break;
+ printer(arg, " <");
+ len -= optlen;
+ optend = p + optlen;
+ switch (code) {
+ case CI_BSD_COMPRESS:
+ if (optlen >= CILEN_BSD) {
+ printer(arg, "bsd %d", p[2]);
+ p += CILEN_BSD;
+ }
+ break;
+ }
+ while (p < optend)
+ printer(arg, " %.2x", *p++);
+ printer(arg, ">");
+ }
+ break;
+ }
+
+ /* dump out the rest of the packet in hex */
+ while (--len >= 0)
+ printer(arg, " %.2x", *p++);
+
+ return p - p0;
+}
+
+/*
+ * We have received a packet that the decompressor failed to decompress.
+ * Issue a reset-req (if we haven't issued one recently).
+ */
+void
+ccp_datainput(unit, pkt, len)
+ int unit;
+ u_char *pkt;
+ int len;
+{
+ fsm *f;
+
+ f = &ccp_fsm[unit];
+ if (f->state == OPENED) {
+ if (!(ccp_localstate[unit] & RACK_PENDING)) {
+ fsm_sdata(f, RESETREQ, f->reqid = ++f->id, NULL, 0);
+ TIMEOUT(ccp_rack_timeout, (caddr_t) f, RACKTIMEOUT);
+ ccp_localstate[unit] |= RACK_PENDING;
+ } else
+ ccp_localstate[unit] |= RREQ_REPEAT;
+ }
+}
+
+/*
+ * Timeout waiting for reset-ack.
+ */
+static void
+ccp_rack_timeout(arg)
+ caddr_t arg;
+{
+ fsm *f = (fsm *) arg;
+
+ if (f->state == OPENED && ccp_localstate[f->unit] & RREQ_REPEAT) {
+ fsm_sdata(f, RESETREQ, f->reqid, NULL, 0);
+ TIMEOUT(ccp_rack_timeout, (caddr_t) f, RACKTIMEOUT);
+ ccp_localstate[f->unit] &= ~RREQ_REPEAT;
+ } else
+ ccp_localstate[f->unit] &= ~RACK_PENDING;
+}
+
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