ipcp.c

基于STM32F107的UDP服务器程序

    } \
    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); \
    u32_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; \
      } \
    } \
  }

#define ACKCIDNS(opt, neg, addr) \
  if (neg) { \
    u32_t l; \
    if ((len -= CILEN_ADDR) < 0) { \
      goto bad; \
    } \
    GETCHAR(citype, p); \
    GETCHAR(cilen, p); \
    if (cilen != CILEN_ADDR || \
        citype != opt) { \
      goto bad; \
    } \
    GETLONG(l, p); \
    cilong = htonl(l); \
    if (addr != 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);

  ACKCIDNS(CI_MS_DNS1, go->req_dns1, go->dnsaddr[0]);

  ACKCIDNS(CI_MS_DNS2, go->req_dns2, go->dnsaddr[1]);

  /*
   * 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!\n"));
  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 LS_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;
  u32_t ciaddr1, ciaddr2, l, cidnsaddr;
  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 \
  }
  
#define NAKCIDNS(opt, neg, code) \
  if (go->neg && \
      ((cilen = p[1]) == CILEN_ADDR) && \
      len >= cilen && \
      p[0] == opt) { \
    len -= cilen; \
    INCPTR(2, p); \
    GETLONG(l, p); \
    cidnsaddr = htonl(l); \
    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\n",
           inet_ntoa(ciaddr1)));
    }
    if (go->accept_remote && ciaddr2) { /* Does he know his? */
      try.hisaddr = ciaddr2;
      IPCPDEBUG((LOG_INFO, "remote IP address %s\n",
           inet_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;
      }
    }
  );

  NAKCIDNS(CI_MS_DNS1, req_dns1,
      try.dnsaddr[0] = cidnsaddr;
        IPCPDEBUG((LOG_INFO, "primary DNS address %s\n", inet_ntoa(cidnsaddr)));
      );

  NAKCIDNS(CI_MS_DNS2, req_dns2,
      try.dnsaddr[1] = cidnsaddr;
        IPCPDEBUG((LOG_INFO, "secondary DNS address %s\n", inet_ntoa(cidnsaddr)));
      );

  /*
  * 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 != LS_OPENED) {
    *go = try;
  }

  return 1;

bad:
  IPCPDEBUG((LOG_INFO, "ipcp_nakci: received bad Nak!\n"));
  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;
  u32_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) { \
    u32_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; \
  }

#define REJCIDNS(opt, neg, dnsaddr) \
  if (go->neg && \
      ((cilen = p[1]) == CILEN_ADDR) && \
      len >= cilen && \
      p[0] == opt) { \
    u32_t l; \
    len -= cilen; \
    INCPTR(2, p); \
    GETLONG(l, p); \
    cilong = htonl(l); \
    /* Check rejected value. */ \
    if (cilong != dnsaddr) { \
      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);

  REJCIDNS(CI_MS_DNS1, req_dns1, go->dnsaddr[0]);

  REJCIDNS(CI_MS_DNS2, req_dns2, go->dnsaddr[1]);

  /*
   * If there are any remaining CIs, then this packet is bad.
   */
  if (len != 0) {
    goto bad;
  }
  /*
   * Now we can update state.
   */
  if (f->state != LS_OPENED) {
    *go = try;
  }
  return 1;

bad:
  IPCPDEBUG((LOG_INFO, "ipcp_rejci: received bad Reject!\n"));
  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/* Requested CIs */,int *len/* Length of requested CIs */,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];
#ifdef OLD_CI_ADDRS
  ipcp_options *go = &ipcp_gotoptions[f->unit];
#endif
  u_char *cip, *next;     /* Pointer to current and next CIs */
  u_short cilen, citype;  /* Parsed len, type */
  u_short cishort;        /* Parsed short value */
  u32_t tl, ciaddr1;      /* Parsed address values */
#ifdef OLD_CI_ADDRS
  u32_t ciaddr2;          /* Parsed address values */
#endif
  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 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((LOG_INFO, "ipcp_reqci: bad CI length!\n"));
      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 */
#ifdef OLD_CI_ADDRS /* Need to save space... */
      case CI_ADDRS:
        IPCPDEBUG((LOG_INFO, "ipcp_reqci: received ADDRS\n"));
        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,