Header file reorganization and cleaning up the public API for pppd version 2.5.0 (#379)

This commit does several things, being a squash-and-merge of a series
of changes; squashed in order not to break bisection.

* Clean up pppd.h, moving declarations that should only be accessed by
  pppd code (not by users of pppd) to a new pppd-private.h.  Also,
  other parts of pppd.h were moved to multilink.h, chap.h, eap.h,
  eui64.h, and a new options.h.

* Provide an API for access to data that is needed by plugins (in no
  particular order):
  - ifname
  - ifunit
  - remote_name
  - remote_number
  - peer_authname
  - status (now called "code" internally)
  - phase
  - doing_multilink
  - multilink_master
  - idle_time_limit
  - link_connect_time
  - max_connect_time
  - link_stats
  - ipparam
  - hostname
  - got_sigterm
  - got_sigusr2
  - got_sighup
  - session_number
  - maxoctets
  - maxoctets_dir
  - debug
  - persist
  - devnam
  - modem
  - peer_authname
  - sync_serial

* Update the version number to 2.5.0.

* Detect availability of stddef.h and stdarg.h.

* Rename some headers:
  - pppcrypt.c/h to crypto_ms.c/h
  - ppp-crypto.c/h to crypto.c/h
  - ppp-crypto-priv.h to crypto-priv.h
  - chap-new.c/h to chap.c/h

* Remove chap-md5.h, crypto-priv.h, eap-tls.h, etc. from the list of
  header files to be installed.

* Provide typedefs for the hook functions.

* Provide a typedef for the "phase" variable.

* Provide a typedef for the link statistics array.

* Remove the option_t typedef.

* Rename the following functions by adding a "ppp_" prefix (with the
  intention that these are a "public" API for use by plugins):
  - option_error
  - add_options
  - int_option,
  - options_from_file
  - script_setenv
  - bad_ip_adrs,
  - netif_get/set_mtu (renamed to ppp_get/set_mtu)
  - get_time
  - timeout
  - untimeout
  - safe_fork
  - sys_close
  - set_session_number
  - update_link_stats (renamed to ppp_get_link_stats)
  - add_notifier (renamed to ppp_add_notify)
  - remove_notifier (renamed to ppp_del_notify)
  - generic_[dis]establish_ppp (to ppp_generic_[dis]establish)

* Rename ppp_devnam to ppp_devname.

* Rename ppp_available() to ppp_check_kernel_support().

* Use unsigned char instead of u_char, unsigned short instead of
  u_short, uint32_t instead of u_int32_t.

* Add const to some declarations

* Update comments

* Change the interface for notifiers to use an enum to identify which
  notifier is to be modified.

* Provide an API for getting the path to a file, with an enum to
  identify different types of file.

* Link plugins with the -DPLUGIN flag

[paulus@ozlabs.org - wrote commit message]

Signed-off-by: Eivind Næss <eivnaes@yahoo.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

1 files changed, 168 insertions, 0 deletions

diff --git a/pppd/chap.h b/pppd/chap.h
new file mode 100644
index 0000000..e693fc9
--- /dev/null
+++ b/pppd/chap.h
@@ -0,0 +1,168 @@
+/*
+ * chap-new.c - New CHAP implementation.
+ *
+ * Copyright (c) 2003 Paul Mackerras. 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. The name(s) of the authors of this software must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission.
+ *
+ * 3. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by Paul Mackerras
+ *     <paulus@samba.org>".
+ *
+ * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
+ * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS, IN NO EVENT SHALL THE AUTHORS 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.
+ */
+
+#ifndef PPP_CHAP_NEW_H
+#define PPP_CHAP_NEW_H
+
+#include "pppdconf.h"
+
+/*
+ * CHAP packets begin with a standard header with code, id, len (2 bytes).
+ */
+#define CHAP_HDRLEN	4
+
+/*
+ * Values for the code field.
+ */
+#define CHAP_CHALLENGE	1
+#define CHAP_RESPONSE	2
+#define CHAP_SUCCESS	3
+#define CHAP_FAILURE	4
+
+/*
+ * CHAP digest codes.
+ */
+#define CHAP_MD5		5
+#define CHAP_MICROSOFT		0x80
+#define CHAP_MICROSOFT_V2	0x81
+
+/*
+ * Semi-arbitrary limits on challenge and response fields.
+ */
+#define MAX_CHALLENGE_LEN	64
+#define MAX_RESPONSE_LEN	64
+
+/* bitmask of supported algorithms */
+#define MDTYPE_MICROSOFT_V2	0x1
+#define MDTYPE_MICROSOFT	0x2
+#define MDTYPE_MD5		0x4
+#define MDTYPE_NONE		0
+
+/* hashes supported by this instance of pppd */
+extern int chap_mdtype_all;
+
+/* Return the digest alg. ID for the most preferred digest type. */
+#define CHAP_DIGEST(mdtype) \
+    ((mdtype) & MDTYPE_MD5)? CHAP_MD5: \
+    ((mdtype) & MDTYPE_MICROSOFT_V2)? CHAP_MICROSOFT_V2: \
+    ((mdtype) & MDTYPE_MICROSOFT)? CHAP_MICROSOFT: \
+    0
+
+/* Return the bit flag (lsb set) for our most preferred digest type. */
+#define CHAP_MDTYPE(mdtype) ((mdtype) ^ ((mdtype) - 1)) & (mdtype)
+
+/* Return the bit flag for a given digest algorithm ID. */
+#define CHAP_MDTYPE_D(digest) \
+    ((digest) == CHAP_MICROSOFT_V2)? MDTYPE_MICROSOFT_V2: \
+    ((digest) == CHAP_MICROSOFT)? MDTYPE_MICROSOFT: \
+    ((digest) == CHAP_MD5)? MDTYPE_MD5: \
+    0
+
+/* Can we do the requested digest? */
+#define CHAP_CANDIGEST(mdtype, digest) \
+    ((digest) == CHAP_MICROSOFT_V2)? (mdtype) & MDTYPE_MICROSOFT_V2: \
+    ((digest) == CHAP_MICROSOFT)? (mdtype) & MDTYPE_MICROSOFT: \
+    ((digest) == CHAP_MD5)? (mdtype) & MDTYPE_MD5: \
+    0
+
+
+/*
+ * The code for each digest type has to supply one of these.
+ */
+struct chap_digest_type {
+	int code;
+
+	/*
+	 * Note: challenge and response arguments below are formatted as
+	 * a length byte followed by the actual challenge/response data.
+	 */
+	void (*generate_challenge)(unsigned char *challenge);
+	int (*verify_response)(int id, char *name,
+		unsigned char *secret, int secret_len,
+		unsigned char *challenge, unsigned char *response,
+		char *message, int message_space);
+	void (*make_response)(unsigned char *response, int id, char *our_name,
+		unsigned char *challenge, char *secret, int secret_len,
+		unsigned char *priv);
+	int (*check_success)(int id, unsigned char *pkt, int len);
+	void (*handle_failure)(unsigned char *pkt, int len);
+
+	struct chap_digest_type *next;
+};
+
+/*
+ * This function will return a value of 1 to indicate that a plugin intend to supply
+ *   a username or a password to pppd through the chap_passwd_hook callback.
+ *
+ * Return a value > 0 to avoid parsing the chap-secrets file.
+ */
+typedef int (chap_check_hook_fn)(void);
+extern chap_check_hook_fn *chap_check_hook;
+
+/*
+ * A plugin can chose to supply its own user and password overriding whatever
+ *   has been provided by the configuration. Hook is only valid when pppd is
+ *   acting as a client.
+ *
+ * The maximum size of the user argument is always MAXNAMELEN
+ * The length of the password is always MAXWORDLEN, however; secrets can't be
+ *   longer than MAXSECRETLEN
+ *
+ * Return a value < 0 to fail the connection.
+ */
+typedef int (chap_passwd_hook_fn)(char *user, char *password);
+extern chap_passwd_hook_fn *chap_passwd_hook;
+
+/*
+ * A plugin can chose to replace the default chap_verify_response function with
+ *   one of their own.
+ */
+typedef int (chap_verify_hook_fn)(char *name, char *ourname, int id,
+			struct chap_digest_type *digest,
+			unsigned char *challenge, unsigned char *response,
+			char *message, int message_space);
+extern chap_verify_hook_fn *chap_verify_hook;
+
+/* Called by digest code to register a digest type */
+extern void chap_register_digest(struct chap_digest_type *);
+
+/* Lookup a digest handler by type */
+extern struct chap_digest_type *chap_find_digest(int digest_code);
+
+/* Called by authentication code to start authenticating the peer. */
+extern void chap_auth_peer(int unit, char *our_name, int digest_code);
+
+/* Called by auth. code to start authenticating us to the peer. */
+extern void chap_auth_with_peer(int unit, char *our_name, int digest_code);
+
+/* Represents the CHAP protocol to the main pppd code */
+extern struct protent chap_protent;
+
+#endif